I am an Assistant Professor at the Digital Metropolis Institute (IMD) of the Federal University of Rio Grande do Norte (UFRN). I received my Ph.D. in Informatics Engineering from the University of Coimbra, Portugal (2017). I was a visiting researcher at the University of California at Los Angeles, United States (UCLA) in 2016/2017 and a postdoctoral researcher at the Institute of Computing of the University of Campinas (UNICAMP) in 2018/2019.

My research interests are in Smart Cities, IoT, 5G, Quality of Experience, Security as well as Cloud and Fog computing.


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Google Scholar https://scholar.google.com.br/citations?user=DvWc9qAAAAAJ DBLP https://dblp.uni-trier.de/pers/hd/i/Immich:Roger SCOPUS https://www.scopus.com/authid/detail.uri?authorId=23990618900 ORCID http://orcid.org/0000-0003-2483-6382 ResearchGate https://www.researchgate.net/profile/Roger_Immich Lattes http://lattes.cnpq.br/0535777592588490 LinkedIn https://www.linkedin.com/in/immich/

Publications

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A Cluster Formation Algorithm for Fog Architectures Based on Mobility Parameters at a Geographically LAN Perspective
Martins VB, de Macedo DDJ, Pioli L and Immich R
Advances on P2P, Parallel, Grid, Cloud and Internet Computing. Springer International Publishing. 2023.
 
Abstract: As Internet of Things (IoT) becomes popular, different approaches to increasing its quality also so. One of the used paradigms to enhance these applications is fog computing. The fog intends to bring computational power closer to the users (edge). This paradigm is known to mitigate costs and energy consumption and also to benefit location-aware applications. As fog environments can cover small to medium areas, these can be used to increase location awareness. To make it possible, researchers have used cluster computing. However, in new scenarios, cluster formation can be a challenge since when manually set, geographical-location parameters can be biased. In this manner, this paper aimed to promote a cluster formation algorithm based on these geographical parameters. To evaluate our proposal, we compared our approach to the original using the standardized EUA dataset through iFogSim v2. The proposed algorithm was capable of creating clusters based on accepted node range and maximum nodes per cluster, operating similarly to the original dataset.
DECONN: Combining Minimum and Neutral Energy Consumption Strategies in IoT Networks
Barbosa L, Dalmazo BL, Cordeiro W, Immich R, Abelém A and Riker A
2022 14th IFIP Wireless and Mobile Networking Conference (WMNC). 2022.
 
Abstract: In Low-Power Internet-of-Things (IoT), energy provisioning is often heterogeneous, meaning that nodes with rechargeable and non-rechargeable batteries coexist and collaborate to support data communication. Non-rechargeable nodes pose the requirement of minimum energy consumption for maximizing their network lifetime. Nodes powered by rechargeable batteries, in turn, must foster neutral energy consumption to avoid battery depletion and overflow. In this context, keeping one subset of nodes in neutral consumption and another subset in minimum consumption while maintaining proper network operation is a complex challenge to solve. To tackle this problem, we propose in this paper the Dual Energy COnsumption for interNet-of-thiNgs (DECONN). DECONN is a distributed solution designed to combine minimum and neutral consumption for IoT networks with heterogeneous energy provision. Using DECONN, nodes with the lowest amount of energy determine the energy consumption of the nodes located in the communication path. We compare DECONN with current IoT low-power standard protocols, such as RPL and CoAP. The results achieved provide evidence that DECONN may outperform standard protocols regarding the amount of saved energy for non-rechargeable and time in neutral operation for rechargeable nodes.
Arquitetura para gerenciamento de dispositivos através de assistentes virtuais comandados por voz
Cesário H, Girão G, Riker A, Dalmazo B and Immich R
Anais do VI Workshop de Computação Urbana. SBC. 2022.
 
Abstract: O gerenciamento e configuração das redes domésticas tem se tornado cada vez mais complexa. Um dos motivos para isto é devido ao aumento no número de dispositivos conectados a sua infraestrutura. A grande variedade de fabricantes e falta de padronização nas funcionalidades disponibilizadas, podem levar os usuários a efetuar configurações equivocadas. Realizar essas configurações pode ser ainda mais desafiador para pessoas que apresentem algum tipo de deficiência. Diante disso, o presente trabalho propõe uma arquitetura em camadas, onde será possível mediante comandos por voz ou texto e utilizando linguagem natural, que configurações complexas sejam realizadas, sem que seja necessário conhecimento técnico avançado relativo a infraestrutura ou especificidades do dispositivo de rede.
Arquitetura para gerenciamento de dispositivos através de assistentes virtuais comandados por voz
Cesario HV, Girao G and Immich R
Thesis at: Universidade Federal do Rio Grande do Norte. 2022.
 
Characterization of the Mobile User Profile Based on Sentiments and Network Usage Attributes
Morais LPd, Immich R, Silva NF, Couto Rosa T and Borges VdCM
Journal of Internet Services and Applications. 2022.
 
Abstract: Providing resources to meet user needs in futuristic mobile networks is still challenging since the network resources like spectrum and base stations do not increase in the same proportion as the accelerated growth of network traffic. Because of this, human/user behavior attributes can assist resource management in dealing with these challenges, which pick up aspects of how the user impacts the usage of mobile networks, such as network usage, the content of interest, urban mobility routines, social networks, and sentiment. A user profile is a combination of user/human behavior attributes. Such profiles are expected to be a knowledge for softwarization enablers to improve the management of future wireless networks fully. Nevertheless, the correlation between human sentiment and wireless and mobile network usage has not been deeply investigated in the literature about the mobile user profile. This work aims to define the user profile using a transfer learning approach for the sentiment classification of WhatsApp messages. A real-life experiment was conducted to collect users’ attributes, namely the WhatsApp messages and network usage. <br />A new data analysis methodology is proposed that consists of a frequent item-set pattern mining (FP-Growth) based on Association Rules, the Chi-squared statistical test, and descriptive statistics. This methodology assesses the correlation between sentiment and network usage in a profound way. Results show that the users participating in the experiment form three groups. The first group, with 55.6% of the users, contains users who present a strong relation between negative sentiment and low network usage and also a strong relation between positive sentiment and high network usage. The second group contains 25.9% of the users and is composed of userswho present a strong relation between positive sentiment and high network usage. The third group contains 18.5% of the users for whom the correlation between sentiment and network usage is still statistical significant, but the strength of this relation is much more weak then in the other two groups. Thus, 81.5% of the users (the first two groups) present a strong relation between user sentiment captured from WhatsApp messages and the network traffic generated by them.
On the Performance of Machine Learning at the Network Edge to Detect Industrial IoT Faults
Santo Y, Dalmazo BL, Immich R and Riker A
2022 IEEE 21st International Symposium on Network Computing and Applications (NCA). 2022.
 
Abstract: Industrial Internet-of-Things (IoT) massively deploys intelligent computing in industrial production and manufacturing environments seeking automation, reliability, and control. Machine Learning models provide intelligent decisions to drive manufacturing systems to the next level of productivity, efficiency, and safety. One of the critical challenges that must be faced is the deployment of Machine Learning models at the network edge to detect data anomalies caused by Industrial IoT hardware failures, since industrial IoT devices are prone to errors and failures. These anomalies can harm the industrial IoT system by producing false alarms, consuming network resources, and affecting productivity. Because of that, it is critical to rely on low latency and high precision detection systems to verify the data received from industrial IoT devices. In light of this, we assessed key performance indicators of five machine learning models running at edge computing, to provide in-depth discussions. The performance results were obtained from an oil refinery scenario using a real industrial IoT dataset. The performance was measured in terms of (a) Accuracy, (b) Precision, (c) Recall, (d) F1 score, (e) Training time, and (f) Response time.
Multimedia services placement algorithm for cloud–fog hierarchical environments
Santos F, Immich R and Madeira ER
Computer Communications. 2022.
 
Abstract: With the rapid development of mobile communication, multimedia services have experienced explosive growth in the last few years. The high quantity of mobile users, both consuming and producing these services to and from the Cloud Computing (CC), can outpace the available bandwidth capacity. Fog Computing (FG) presents itself as a solution to improve on this and other issues. With a reduction in network latency, real-time applications benefit from improved response time and greater overall user experience. Taking this into account, the main goal of this work is threefold. Firstly, it is proposed a method to build an environment based on Cloud–Fog Computing (CFC). Secondly, it is designed two models based on Autoregressive Integrated Moving Average (ARIMA) and Long Short-Term Memory (LSTM). The goal is to predict demand and reserve the nodes’ storage capacity to improve the positioning of multimedia services. Later, an algorithm for the multimedia service placement problem which is aware of data traffic prediction is proposed. The goal is to select the minimum number of nodes, considering their hardware capacities for providing multimedia services in such a way that the latency for servicing all the demands is minimized. An evaluation with actual data showed that the proposed algorithm selects the nodes closer to the user to meet their demands. This improves the services delivered to end-users and enhances the deployed network to mitigate provider costs. Moreover, reduce the demand to Cloud allowing turning off servers in the data center not to waste energy.
MoHRiPA—An Architecture for Hybrid Resources Management of Private Cloud Environments
Andreazi GT, Estrella JC, Bruschi SM, Immich R, Guidoni D, Alves Pereira Júnior L and Meneguette RI
Sensors. 2021.
 
Abstract: The high demand for data processing in web applications has grown in recent years due to the increased computing infrastructure supply as a service in a cloud computing ecosystem. This ecosystem offers benefits such as broad network access, elasticity, and resource sharing, among others. However, properly exploiting these benefits requires optimized provisioning of computational resources in the target infrastructure. Several studies in the literature improve the quality of this management, which involves enhancing the scalability of the infrastructure, either through cost management policies or strategies aimed at resource scaling. However, few studies adequately explore performance evaluation mechanisms. In this context, we present the MoHRiPA—Management of Hybrid Resources in Private cloud Architecture. MoHRiPA has a modular design encompassing scheduling algorithms, virtualization tools, and monitoring tools. The proposed architecture solution allows assessing the overall system’s performance by using complete factorial planning to identify the general behavior of architecture under high demand of requests. It also evaluates workload behavior, the number of virtualized resources, and provides an elastic resource manager. A composite metric is also proposed and adopted as a criterion for resource scaling. This work presents a performance evaluation by using formal techniques, which analyses the scheduling algorithms of architecture and the experiment bottlenecks analysis, average response time, and latency. In summary, the proposed MoHRiPA mapping resources algorithm (HashRefresh) showed significant improvement results than the analyzed competitor, decreasing about 7% percent in the uniform average compared to ListSheduling (LS).
Representação e Aplicação de Políticas de Segurança em Firewalls de Redes Híbridas
Fiorenza M, Kreutz D, Mansilha R, Macedo D, Feitosa E and Immich R
Anais do XXXIX Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos. SBC. 2021.
 
Abstract: O gerenciamento de políticas de segurança em firewalls de redes híbridas é um processo desafiador, principalmente devido a diversidade de soluções e fabricantes (e.g., Cisco NGFW, Check Point, Fortigate, IPTables), cada um com suas linguagens, interfaces e modelos de operação. Neste trabalho é proposta uma linguagem genérica para representação de políticas de segurança utilizadas em firewalls, denominada FWlang. A linguagem foi especificada para representar os seis tipos de políticas de firewalls modernos, incluindo ACL, NAT 1to1, NAT Nto1, traffic shapping, roteamento estático e filtros de URL, e implementada e incorporada à solução de gerenciamento de firewalls FWunify. A avaliação demonstra o potencial de simplificação apresentado pela linguagem, chegando a uma redução de 72% no número de termos necessários para aplicar um determinado grupo de políticas a três firewall diferentes.
Video Streaming Analysis in Multi-tier Edge-Cloud Networks
Gama ES, De Araújo LON, Immich R and Bittencourt LF
2021 8th International Conference on Future Internet of Things and Cloud (FiCloud). 2021.
 
Abstract: Video streaming services represent most internet traffic, and according to Cisco forecasts, in 2022, 82% of all internet traffic will be dominated by video streaming. This includes current video services as well as innovative services such as Real-Time video Streaming and future cloud gaming, whereas, for mobile devices, this estimate represents 78% of all mobile data traffic. A good cloud architecture partially solves some issues related to the live stream and Video on Demand (VoD) services to accommodate video traffic. However, a centralized cloud service introduces some issues such as higher latency and core network congestion. Therefore, to improve video services, it is paramount to distribute video streams according to their requirements properly: a real-time video streaming infrastructure is an interactive service that needs reduced delays (a few milliseconds). At the same time, a non-interactive VoD delivery can tolerate higher delays without impairing the quality of experience. This work discusses and gives evidence for the need for proper management and orchestration of video delivery over the Internet as it is core to the smooth coexistence of video services in multi-tier edge/cloud environments. The results assessment corroborate that well-defined video management can considerably increase the end-user QoE.
Analysis of ML Algorithms to Support Elastic Service Chaining in eHealth Vertical Applications
Jardim S, Dantas Silva FS, Neto A, Bustos H, Immich R and Fontes R
2021 International Wireless Communications and Mobile Computing (IWCMC). 2021.
 
Abstract: The efficient design of SFC-enabled eHealth applications requires an accurate provision of the underlying infrastructure. This provision requires both computing and networking resources to meet stringent QoS requirements under any conditions of service demand. Cloud providers often offer automatic elasticity strategies based on monitoring specific metrics that lead to a waste of resources, time/energy consumption, and the problem of starvation with competing services. Our findings provide evidence that proactive-based elasticity overcomes these issues, when assisted by Machine Learning (ML) methods for predicting Internet traffic load. An optimal autoscaling algorithm depends on high precision and fast predictions to provide accurate results. Thus, this paper assesses ML algorithms to support SFC-enabled eHealth vertical applications. The experimental results suggest that the evaluated models achieved similar accuracy metrics, with an MLP architecture delivering the best performance in terms of time training and average prediction time.
TRIAD: Whale Optimization Algorithm for 5G-IoT Resource Allocation Decision in Edge Computing
Lieira DD, Quessada MS, Cristiani AL, Immich R and Meneguette RI
2021 16th Iberian Conference on Information Systems and Technologies (CISTI). 2021.
 
Abstract: The massive growth in the number of 5G-IoT devices circulating in the world has increased the demand for computing resources in recent years. That way, it is necessary to search for the development of new solutions or improvements to existing ones. Edge computing is one of the solutions that have been used to improve the care of these types of devices. In this work, we proposed a mechanism that uses the whale optimization algorithm for 5G-IoT resource allocation decision in edge computing (TRIAD). The TRIAD was compared with the Greedy and Reliable techniques, available in the literature. The results show that the proposed algorithm had excellent efficiency in the service of the devices, in addition to denying fewer requests and blocking fewer devices during the search. The TRIAD, in some situations of the simulation, served approximately 265% more services, denied 56% less requests and blocked 65% less services.
Seamless MANO of multi-vendor SDN controllers across federated multi-domains
Neto EP, Silva FSD, Schneider LM, Neto AV and Immich R
Computer Networks. 2021.
 
Abstract: The upcoming 5G networks promise to provide end-to-end network service delivery that spans across Cloud-Network federated multi-domains while providing monolithic service guarantees. By adopting a Cloud-Network federated multi-domain approach, heterogeneity raises a number of challenging Management and Orchestration (MANO) perspectives, especially concerning the need to deal with SDN controllers of multi-vendor approaches that lack a standard Northbound API. In this work, we tackle the issue of providing a seamless MANO of SDN Controllers running in Cloud-Network federated multi-domains. Owing to the weaknesses and limitations of the related works, we propose the WAN Infrastructure Manager Agnostic (WIMA) that enables a seamless and vendor-agnostic MANO abstraction to run on top of federated SDN multi-domains. The WIMA provides a common Northbound API for external triggering, maintains a global topology view of the federation as a whole, and deals with each SDN Controller directly by deploying an ontology-based scheme for efficient Northbound API mapping. The effectiveness and performance impact of WIMA was assessed in an emulated testbed with homogeneous (“Hom”) and heterogeneous (“Het”) multi-domain SDN control-planes, along with a varying density of active Tenants which simultaneously makes flow stress data connections during an experimental time of 900 s. The obtained results reveal that WIMA’s MANO abstraction system is able to connect around 52.66% (“Het”) and 86.87% (“Hom”) more end-to-end data flows across the federated SDN multi-domains while adding greater agility 52.72% (“Het”) and 85.27% (“Hom”) than the rival Baseline solution. Thus, the WIMA’s central logic has proven to be a suitable and feasible means of ensuring the MANO framework’s efficiency atop the multi-domain SDN Controllers within a Cloud-Network federation while optimizing the operation time.
dh-aes-p4: On-premise encryption and in-band key-exchange in P4 fully programmable data planes
Oliveira I, Neto E, Immich R, Fontes R, Neto A, Rodriguez F and Rothenberg CE
2021 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN). 2021.
 
Abstract: Software-Defined Networking (SDN) fostered unprecedented advances over legacy networks by employing a central-logic control plane to coordinate data-plane nodes in a net-programmable manner. From the security view, control applications that run atop the SDN controller are in charge of establishing secure data-plane connections between pairs of data-plane forwarding nodes. The Diffie–Hellman (DH) is a widely used solution for cryptographic key exchange between endpoints. However, traditional DH implementations impose high computational costs and key management hazards, leading to issues in the SDN central-logic control plane. This paper introduces the dh-aes-p4, which tackles the penalties of legacy SDN security solutions by turning the data plane into fully programmable P4 nodes. The proposed solution allows P4-enabled data plane nodes to establish secure channels between each other. In doing that, it is possible to harness in-band DH key exchange with AES encryption, enclosing on-site features to generate keys dynamically and enforcing them autonomously and high-agile without SDN controller central-logic intervention. A prototype was designed to validate the feasibility and estimate performance impacts of dh-aes-p4 concerning regular SDN central logic.
Mobile Edge Computing for Content Distribution and Mobility Support in Smart Cities
do Prado PF, Peixoto MLM, Araújo MC, Gama ES, Gonçalves DM, Silva MVS, Immich R, Madeira ERM and Bittencourt LF
Mobile Edge Computing. Springer International Publishing. 2021.
 
Abstract: The pervasiveness of mobile devices is a common phenomenon nowadays, and with the emergence of the Internet of Things (IoT), an increasing number of connected devices are being deployed. In Smart Cities, data collection, processing, and distribution play critical roles in everyday quality of life and city planning and development. The use of Cloud computing to support massive amounts of data generated and consumed in Smart Cities has some limitations, such as increased latency and substantial network traffic, hampering support for a variety of applications that need low response times. In this chapter, we introduce and discuss aspects of distributed multi-tiered Mobile Edge Computing (MEC) architectures, which offer data storage and processing capabilities closer to data sources and data consumers, taking into account how mobility impacts the management of such infrastructure. The main goal is to address topics on how such infrastructure can be used to support content distribution from and to mobile users, how to optimize the resource allocation in such infrastructure, as well as how an intelligent layer can be added to the MEC/Fog infrastructure. Furthermore, a multifaceted literature review is given, as well as the open issues and challenging aspects of resource and application management will also be discussed in this chapter.
Multimedia Microservice Placement in Hierarchical Multi-tier Cloud-to-Fog Networks
Santos F, Immich R and Madeira E
2021 IFIP/IEEE International Symposium on Integrated Network Management (IM). 2021.
 
Abstract: The demand for multimedia services in mobile networks has increased in the last years. The high quantity of users mobile, both consuming and producing multimedia content to and from the Cloud can outpace the available bandwidth capacity. Notwithstanding the many benefits of Cloud Computing (CC), it has been noticed that it does not provide adequate latency in areas with high demands for multimedia content. Furthermore, using Fog Computing (FG) it is possible to improve on the above-mentioned issues, being especially useful in latency-sensitive applications such nodes are physically much closer to devices if compared to centralized data centers. The main goal of this work is twofold, first, it proposed a method to design/create a hierarchical multi-tier Cloud-to-Fog network. Second, it introduced a novel multimedia microservices placement algorithm for multi-tier Fog nodes. The performance assessment was composed of two months of real-world mobile network traffic data from Milan, Italy. The obtained results showed that our algorithm selects the nodes closer to the user to meet their demands. This decision improves the services delivered to end-users, for example, a local Fog node can instead be responsible for the video stream and is far quicker than offloading the processing to a centralized cloud platform.
Towards the Categorization of Brazilian Financial Market Headlines
Schmitz M, Immich R, Pessin G and Pereira Rocha Filho G
IEEE Latin America Transactions. 2021.
 
Abstract: Financial market news portals are valuable sources of information as they hold great power over investors’ decision-making processes. Due to the vast amount of text data produced by news portals, several studies have been conducted to comprehend the behavioral variations of texts and automate the categorization of short texts. However, extracting useful information that influences investors’ decision-making process is not a trivial task, given that news portals use a heterogeneous and specific language for each content produced, making it challenging to generate a standard document format. This work proposes GOOSE, a solution for the cateGOrizatiOn of Short texts derived from multiple sources of information, to portray the financial market’s current situation. To this end, GOOSE is based on Bidirectional Long Short-Term Memory (Bi-LSTM) and GloVe Embeddings to increase reliability in the short texts classification process. That way, GOOSE obtains data from news portals, which, once combined with a word embedding mechanism, are used as input for the Bi-LSTM to classify financial market news texts. The results obtained showed that GOOSE’s efficiency in categorizing texts had an accuracy of 84% but also demonstrated the feasibility of its use in the extraction of information from financial market news portals.
Análise da Performance de Streaming de Vídeos Adaptativos em Redes Veiculares V2I
Abrahao P, Immich R and Goldman A
Anais Estendidos do XXXVIII Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos. SBC. 2020.
 
Abstract: O emprego de carros com equipamentos de vídeo, assim como veículos conectados e autônomos, tem experienciado um aumentando considerável. Os números de serviços e aplicações a disposição em Vehicular Ad-hoc Networks (VANETs) seguem a mesma tendência. Esse tipo de rede é contemplado com um componente central de sistemas de transporte inteligentes, que provê um suporte para uma grande variedade de aplicações, incluindo serviço de vídeo. Esses serviços permeiam a rede com conteúdo de vídeo diariamente. Com o objetivo de entender melhor o comportamento destes serviços, este trabalho realiza uma análise da performance de streaming de vídeos adaptativos em VANETs. Resultado das simulações comprovam, através de métricas de QoS e QoE, que o MPEG-DASH apresenta mais vantagens em cenários menos densos, ainda que estes apresentem características de movimentação acentuada.
Towards a distributed and infrastructure-less vehicular traffic management system
Akabane AT, Immich R, Bittencourt LF, Madeira ER and Villas LA
Computer Communications. 2020.
 
Abstract: In the past few years, several systems have been proposed to deal with issues related to the vehicular traffic management. Usually, their solutions include the integration of computational technologies such as vehicular networks, central servers, and roadside units. Most systems use a hybrid approach, which means they still need a central entity (central server or roadside unit) and Internet connection to find out an en-route event as well as alternative routes for vehicles. It is easy to understand the need for a central entity because selecting the most appropriate vehicle to perform aforementioned procedures is a difficult task. This is especially true in a highly dynamic network. In addition to that, as far as we know, there are very few systems that apply the altruistic approach (not selfish behavior) to routing decisions. Because of that, the issue addressed in this work is how to perform the vehicular traffic management, when an en-route event is detected, in a distributed, scalable, and cost-effective fashion. To deal with these issues, we proposed a distributed vehicle traffic management system, named as dEASY (distributed vEhicle trAffic management SYstem). The dEASY system was designed and implemented on a three-layer architecture, namely environment sensing and vehicle ranking, knowledge generation and distribution, and knowledge consumption. Each layer of the dEASY architecture is responsible for dealing with the main issues that were not addressed in related works or could be improved. The three-layer architecture is arranged as follows: the first layer deals with the task of selecting the most appropriate vehicle to perform data forwarding and/or knowledge generation, the second one addresses the knowledge generation and distribution, and the third layer applies an altruistic approach to choose an alternative route. Simulation results have shown that, compared with other systems from the literature, our proposed system has lower network overhead due to applied vehicle selection and broadcast suppression mechanisms. On average, dEASY also outperformed all other competitors in what regards to the travel time and time lost metrics. Through the analysis of results, it is possible to conclude that our infrastructure-less system is scalable and cost-effective.
ATRIP: Architecture for Traffic Classification Based on Image Processing
Cristiani AL, Immich R, Akabane AT, Madeira ERM, Villas LA and Meneguette RI
Vehicles. 2020.
 
Abstract: With the increase of vehicles in large urban centers, there is also an increase in the number of traffic jams and accidents on public roads. The development of a proper Intelligent Transport System (ITS) could help to alleviate these problems by assisting the drivers on route selections to avoid the most congested road sections. Therefore, to improve on this issue, this work proposes an architecture to aid an ITS to detect, analyze, and classify the traffic flow conditions in real time. This architecture also provides a control room dashboard to visualize the information and notify the users about the live traffic conditions. To this end, the proposed solution takes advantage of computer vision concepts to extract the maximum information about the roads to better assess and keep the drivers posted about the traffic conditions on selected highways. The main contribution of the proposed architecture is to perform the detection and classification of the flow of vehicles regardless of the luminosity conditions. In order to evaluate the efficiency of the proposed solution, a testbed was designed. The obtained results show that the accuracy of the traffic classification rate is up to 90% in daylight environments and up to 70% in low light environments when compared with the related literature.
S3AS: uma Solução de Autenticação e Autorização através de Aplicativos de Smartphones
Fernandes R, Paz G, Kretuz D, Mansilha R, Jenuario T and Immich R
Revista Eletrônica Argentina-Brasil de Tecnologias da Informação e da Comunicação. 2020.
 
Abstract: A crescente utilização de aplicativos, especialmente em dispositivosmóveis, como forma de autenticação de usuários está trazendo à tona novasoportunidades e desafios de segurança. Com o objetivo de modernizar suas formasde acesso, algumas instituições estão adotando QR Codes estáticos geradosa partir de informaçõoes simples e imutáveis, como o CPF dos seus associados.Esse procedimento possui implementação e verificação fáceis, mas representauma vulnerabilidade crítica sob a ótica da segurança. Com o objetivo de mitigaressa vulnerabilidade, este trabalho propõe uma Solução de Autenticaçãoe Autorização através de Aplicativos de Smartphones, denominada S3AS. Asolução proposta é composta de dois protocolos principais, um de vinculaçãode credenciais do usuário (i.e., identificação) ao dispositivo móvel e outro para a geração de códigos de autenticação descartáveis (OTACs). Ambos os protocolos foram formalmente verificados utilizando a ferramenta de verificação automática Scyther. Os resultados demonstram que os protocolos da S3AS são robustos e seguros segundo as an´alises automáticas realizadas com a ferramenta Scyther. Como forma de demonstrar o funcionamento e a viabilidade técnicada solução, foi implementado também um protótipo que simula o controle de acesso utilizando catracas eletrônicas.
Auth4App: Protocols for Identification and Authentication using Mobile Applications
Kreutz D, Fernandes R, Paz G, Jenuario T, Mansilha R, Immich R and Miers C
Anais do XX Simpósio Brasileiro em Segurança da Informação e de Sistemas Computacionais. SBC. 2020.
 
Fog Computing on Constrained Devices: Paving the Way for the Future IoT
Pisani F, de Oliveira F, Gama ES, Immich R, Bittencourt LF and Borin E
Advances in Edge Computing: Massive Parallel Processing and Applications. IOS Press. 2020.
 
Abstract: In the long term, the Internet of Things (IoT) is expected to become an integral part of people’s daily lives. In light of this technological advancement, an ever-growing number of objects with limited hardware may become connected to the Internet. In this chapter, we explore the importance of these constrained devices as well as how we can use them in conjunction with fog computing to change the future of the IoT. First, we present an overview of the concepts of constrained devices, IoT, and fog and mist computing, and then we present a classification of applications according to the amount of resources they require (e.g., processing power and memory). After that, we tie in these topics with a discussion of what can be expected in a future where constrained devices and fog computing are used to push the IoT to new limits. Lastly, we discuss some challenges and opportunities that these technologies may bring.
Towards Improved Vehicular Information-Centric Networks by Efficient Caching Discovery
Rondon LB, Immich R, Filho GPR, Venâncio Neto A, Leone Maciel Peixoto M and Villas LA
Vehicles. 2020.
 
Abstract: The number of connected cars and the massive consumption of digital content on the Internet have increased daily. However, the high mobility of the vehicles, coming from patterns’ variation over time, makes efficient large-scale content distribution quite challenging. In light of this, the emerging Vehicular Named Data Network (VNDN) architecture provides support for content-centric network communications and caching capabilities, which allows reliable and larger-scale content delivery over Vehicular Ad-Hoc Networks (VANETs). This notwithstanding, the high number of interest packets in VNDN tends to introduce broadcast storm occurrences during the cache discovery process. Thus, network performance degradation comes up for the influence of both increased packet loss rates and delays on content recovery during communication between vehicles. This work proposes a new cache discOVEry pRoTocol (OVERT VNDN), which combines the computational geometry and degree centrality concepts to tackle the VNDN performance degradation challenges and issues. The main idea behind OVERT VNDN is to choose the most appropriate relay vehicles to engage interest packets’ delivery within the VNDN, seeking to achieve higher network performance by optimizing broadcast storm incidence. The obtained results suggest that OVERT VNDN outperforms its competitor in the following key performance indicators: (i) improving the cache discovery process by 120.47%; (ii) enhancing the content delivery rate by 43%; and (iii) reducing the number of interest packets by 80.99%.
Aplicando Redes Sociais Veiculares para Aprimorar o Gerenciamento da Mobilidade Urbana
Akabane A, Immich R, Madeira E and Villas L
Anais do XXXVII Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC). SBC. 2019.
 
Abstract: O Sistema Avançado de Gerenciamento de Tráfego (ATMS) é cada vez mais utilizado por gestores de mobilidade urbana para aprimorar o gerenciamento de tráfego veicular. Muitos ATMS empregam soluções centralizadas devido à dificuldade de selecionar os veículos mais relevantes, em redes altamente dinâmicas, para detectar congestionamentos e sugerir rotas alternativas. Além disso, tais soluções nem sempre são escaláveis. Por outro lado, a solução distribuída necessita previamente segmentar todo o cenário para selecionar os veículos. Além disso, tal solução sugere rotas alternativas, de maneira egoísta, que podem levar ao congestionamento secundário. Com base nessas lacunas encontradas, foi proposto um sistema distribuído de gerenciamento de mobilidade urbana baseado no paradigma das redes sociais veiculares (VSNs) chamado MAESTRO. Tal paradigma surgiu a partir da integração dos dispositivos de comunicação sem-fio e das redes sociais no ambiente veicular. Assim duas diferentes abordagens podem ser exploradas em VSNs: Social Network Analysis (SNA) e Social Network Concepts (SNC). Ambas abordagens foram aplicadas no sistema MAESTRO. Os resultados das simulações mostraram que o uso dos SNA e SNC, no ambiente veicular, tem grande potencial em aumentar a escalabilidade do sistema e também aprimorar a eficiência no gerenciamento da mobilidade urbana.
Exploiting Vehicular Social Networks and Dynamic Clustering to Enhance Urban Mobility Management
Akabane AT, Immich R, Pazzi RW, Madeira ERM and Villas LA
Sensors. MDPI AG. 2019.
 
Abstract: Transport authorities are employing advanced traffic management system (ATMS) to improve vehicular traffic management efficiency. ATMS currently uses intelligent traffic lights and sensors distributed along the roads to achieve its goals. Furthermore, there are other promising technologies that can be applied more efficiently in place of the abovementioned ones, such as vehicular networks and 5G. In ATMS, the centralized approach to detect congestion and calculate alternative routes is one of the most adopted because of the difficulty of selecting the most appropriate vehicles in highly dynamic networks. The advantage of this approach is that it takes into consideration the scenario to its full extent at every execution. On the other hand, the distributed solution needs to previously segment the entire scenario to select the vehicles. Additionally, such solutions suggest alternative routes in a selfish fashion, which can lead to secondary congestions. These open issues have inspired the proposal of a distributed system of urban mobility management based on a collaborative approach in vehicular social networks (VSNs), named SOPHIA. The VSN paradigm has emerged from the integration of mobile communication devices and their social relationships in the vehicular environment. Therefore, social network analysis (SNA) and social network concepts (SNC) are two approaches that can be explored in VSNs. Our proposed solution adopts both SNA and SNC approaches for alternative route-planning in a collaborative way. Additionally, we used dynamic clustering to select the most appropriate vehicles in a distributed manner. Simulation results confirmed that the combined use of SNA, SNC, and dynamic clustering, in the vehicular environment, have great potential in increasing system scalability as well as improving urban mobility management efficiency.
SAAS: Uma Solução de Autenticação para Aplicativos de Smartphones
Fernandes R, Paz G, Kreutz D, Mansilha R and Immich R
4o Workshop Regional de Segurança da Informação e de Sistemas Computacionais. 2019.
 
Abstract: A crescente utilização de aplicativos em dispositivos móveis como forma de autenticação de usuários está trazendo à tona diferentes oportunidades e desafios de segurança. Por exemplo, o cartão virtual do SESC-RS utiliza um QR Code estático, contendo apenas o CPF do associado, como forma de autenticação, o que representa uma vulnerabilidade crítica sob a ótica da segurança. Neste trabalho é proposta uma solução de autenticação para aplicativos de dispositivos móveis, denominada SAAS, composta de dois protocolos principais, um de vinculação de credenciais do usuário (i.e. identificação) ao dispositivo móvel e outro para a geração de códigos de autenticação descartáveis, denominados OTACs. Como forma de demonstrar o funcionamento e a viabilidade da solução, foi implementado um protótipo que simula o controle de acesso utilizando catracas eletrônicas, uma das finalidades para as quais o cartão virtual do SESC-RS é utilizado.
Urnas Eletrônicas no Brasil: linha do tempo, evolução e falhas e desafios de segurança
Ferrao I, Chervinski JO, da Silva S, Kreutz D, Immich R, Kepler F and Righi R
Revista Brasileira de Computação Aplicada. 2019.
 
Abstract: Mesmo após anos de implantação e evolução do voto eletrônico, as urnas eletrônicas continuam sendo alvo crescente de críticas, tanto por parte de especialistas em segurança da informação quanto pela sociedade. Os principais desafios no uso desse tipo de urnas são garantir a transparência, a auditabilidade e a confiabilidade do sistema de votação, ao mesmo tempo em que garante-se também a integridade, a confidencialidade e a privacidade dos votos. No sistema brasileiro, entretanto, os principais pontos criticados são exatamente a pouca transparência e a restrita auditabilidade das urnas, que nos poucos casos em que foram concedidos à sociedade civil fora de períodos eleitorais, levaram a descobertas de falhas de segurança. Não é surpresa, portanto, que isso, somado à atual impossibilidade de se auditar os resultados eleitorais, coloque em cheque a confiabilidade no sistema. Neste survey, nós apresentamos e analisamos a evolução dos sistemas de votação eletrônica com o objetivo de criar uma linha do tempo e discutir falhas de seguranças e desafios em aberto. Também identificamos e discutimos questões importantes a serem respondidas para que um sistema baseado em urnas eletrônicas possa, de fato, ser um dos principais mecanismos de eleição de representantes em uma democracia.
Multi-tier Edge-to-Cloud Architecture for Adaptive Video Delivery
Immich R, Villas L, Bittencourt L and Madeira E
2019 7th International Conference on Future Internet of Things and Cloud (FiCloud). 2019.
 
Abstract: In the last few years, there has been a rapid proliferation of a wide range of real-time video services and applications. These technologies flood the wireless systems with video content on a daily basis. As a result of this sharp increase in video traffic, the prospect of errors due to network interference and congestion rises. Incidentally, the adoption of the 5th generation of wireless systems (5G) will allow this growth to be even greater due to its high bandwidth capacity and low latency. However, even with these improvements on the wireless capabilities, a reliable and high-quality video transmission still imposes several challenges, such as how to handle a large number of heterogeneous devices and how to better use the resource-richer Edge, Fog, and Cloud computing sources to meet the user's requirements. To overcome these issues, this work proposes a multi-tier video delivery architecture relying upon several technologies such as Multi-access Edge computing (MEC), 5G slices, and microservice placement/chaining. Furthermore, to assess the proposed idea an experimental proof-of-concept testbed of the multi-tier architecture was designed, implemented, and evaluated using real-world tools and actual video sequences. The results obtained supported our claim that a multi-tier video delivery system is feasible and can greatly benefit the end-users.
Computação Urbana da Teoria à Prática: Fundamentos, Aplicações e Desafios
Rodrigues DO, Santos FA, Filho GPR, Akabane AT, Cabral R, Immich R, Junior WL, Cunha FD, Guidoni DL, Silva TH, Rosario D, Cerqueira E, Loureiro AAF and Villas LA
Thesis at: Minicurso do Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC). 2019.
 
Abstract: The growing of cities has resulted in innumerable technical and managerial challenges for public administrators such as energy consumption, pollution, urban mobility and even supervision of private and public spaces in an appropriate way. Urban Computing emerges as a promising paradigm to solve such challenges, through the extraction of knowledge, from a large amount of heterogeneous data existing in urban space. Moreover, Urban Computing correlates urban sensing, data management, and analysis to provide services that have the potential to improve the quality of life of the citizens of large urban centers. Consider this context, this chapter aims to present the fundamentals of Urban Computing and the steps necessary to develop an application in this area. To achieve this goal, the following questions will be investigated, namely: (i) What are the main research problems of Urban Computing?; (ii) What are the technological challenges for the implementation of services in Urban Computing?; (iii) What are the main methodologies used for the development of services in Urban Computing?; and (iv) What are the representative applications in this field?
iMOB: An Intelligent Urban Mobility Management System Based on Vehicular Social Networks
Akabane AT, Immich R, Madeira ERM and Villas LA
IEEE Vehicular Networking Conference (VNC). 2018.
 
Abstract: The vehicular social networks (VSNs) paradigm is a special class of vehicular networks (VANETs), where features and social aspects are taken into account. Starting from this concept, two different approaches can be applied in VSNs, which are the social network analysis (SNA) measures and the social networking concepts (SNC). In the past few years, several systems have been proposed to deal with traffic congestion problems. They rely on integrating computational technologies such as VANETs, central server, and roadside units. A number of systems employ a hybrid approach, this means that they still need an infrastructure support (central server or roadside unit) to achieve the goals of the system. In order to surpass that, this work deals with the question of how to manage the urban mobility, when an en-route event is detected, in an infrastructure-less environment and scalable fashion. To achieve that, the main goal is to apply VSNs to investigate how SNA measures and SNC can help in the urban mobility management in a distributed fashion. To this end, it was proposed the iMOB system, which is an intelligent urban mobility management system. The system consists of the 3-tier: the environment sensing (bottom tier), the vehicle ranking mechanism (middle tier), and the altruistic rerouting decision (upper tier). The SNA egocentric betweenness measure is applied in the middle tier and SNCs such as social interactions and virtual community were utilized in the upper tier. iMOB was evaluated in simulation-based experiments being able to outperform all its competitors in all assessed metrics. The results obtained lead us to conclude that the application of concepts and analysis of social network, in a vehicular environment, have great potential to improve the reliability and efficiency of urban mobility management systems in a practical and cost-effective way.
Distributed egocentric betweenness measure as a vehicle selection mechanism in vanets: A performance evaluation study
Akabane AT, Immich R, Pazzi RW, Madeira ER and Villas LA
Sensors. Multidisciplinary Digital Publishing Institute. 2018.
 
Abstract: In the traditional approach for centrality measures, also known as sociocentric, a network node usually requires global knowledge of the network topology in order to evaluate its importance. Therefore, it becomes difficult to deploy such an approach in large-scale or highly dynamic networks. For this reason, another concept known as egocentric has been introduced, which analyses the social environment surrounding individuals (through the ego-network). In other words, this type of network has the benefit of using only locally available knowledge of the topology to evaluate the importance of a node. It is worth emphasizing that in this approach, each network node will have a sub-optimal accuracy. However, such accuracy may be enough for a given purpose, for instance, the vehicle selection mechanism (VSM) that is applied to find, in a distributed fashion, the best-ranked vehicles in the network after each topology change. In order to confirm that egocentric measures can be a viable alternative for implementing a VSM, in particular, a case study was carried out to validate the effectiveness and viability of that mechanism for a distributed information management system. To this end, we used the egocentric betweenness measure as a selection mechanism of the most appropriate vehicle to carry out the tasks of information aggregation and knowledge generation. Based on the analysis of the performance results, it was confirmed that a VSM is extremely useful for VANET applications, and two major contributions of this mechanism can be highlighted: (i) reduction of bandwidth consumption; and (ii) overcoming the issue of highly dynamic topologies. Another contribution of this work is a thorough study by implementing and evaluating how well egocentric betweenness performs in comparison to the sociocentric measure in VANETs. Evaluation results show that the use of the egocentric betweenness measure in highly dynamic topologies has demonstrated a high degree of similarity compared to the sociocentric approach.
TRUSTed: A Distributed System for Information Management and Knowledge Distribution in VANETs
Akabane AT, Immich R, Pazzi RW, Madeira ERM and Villas LA
2018 IEEE Symposium on Computers and Communications (ISCC). 2018.
 
Abstract: The constant sharing of information among vehicles is of vital importance to provide different types of service in Intelligent Transportation Systems (ITS). Typically, ITS apply the sharing benefit to carrying out tasks such as extracting knowledge of vehicle traffic conditions and its distribution. The ITS that use this approach are able to perform the knowledge distribution, however, they lack of mechanisms to select the most appropriate vehicles to do so. It is common, in these systems, such tasks are performed by all vehicles. Consequently, it could easily cause a network overhead because of the highly redundant knowledge about the traffic that is being transmitted. With this in mind, we propose a system for information management and knowledge distribution named TRUSTed. The proposed system applies the egocentric betweenness measure to select the most relevant vehicle to carry out such tasks. Simulation results have shown that TRUSTed outperforms other systems found in the literature in several requirements.
Transmissão de Vídeo em Tempo Real em Redes AD HOC
Andrei A, Abrahao P, Immich R and Goldman A
Anais do XXXVI Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (WTG SBRC). SBC. 2018.
 
Abstract: Nos próximos anos é esperado um grande crescimento da transmissão de vídeos em redes sem fio, especialmente em dispositivos móveis. Baseandose nesta crescente demanda, o principal objetivo deste trabalho é o de realizar uma análise quantitativa e qualitativa sobre a transmissão de vídeo em tempo real entre dispositivos móveis. Com isto, é esperado obter-se um melhor entendimento de alguns aspectos ligadosá transmissão de dados. Para tal, foram analisadas algumas formas de transmissão de pacotes na rede para vídeo ao vivo. Através de simulações foi possível realizar comparações entre as diversas formas afim de classificá-las quanto sua qualidade e a escalabilidade na rede. As comparações foram feitas entre os protocolos TCP, UDP e a técnica de transmissão DASH através de simulações feitas no OMNeT++ e o INET Framework. Assim, fizemos análises com as métricas de atraso na entrega dos pacotes, quantidade total de KiB recebidos pelo dispositivo destino e a taxa de pacote recebidos e requisitados.
The Internet of Things, Fog and Cloud continuum: Integration and challenges
Bittencourt L, Immich R, Sakellariou R, Fonseca N, Madeira E, Curado M, Villas L, DaSilva L, Lee C and Rana O
Internet of Things. 2018.
 
Abstract: The Internet of Things needs for computing power and storage are expected to remain on the rise in the next decade. Consequently, the amount of data generated by devices at the edge of the network will also grow. While cloud computing has been an established and effective way of acquiring computation and storage as a service to many applications, it may not be suitable to handle the myriad of data from IoT devices and fulfill largely heterogeneous application requirements. Fog computing has been developed to lie between IoT and the cloud, providing a hierarchy of computing power that can collect, aggregate, and process data from/to IoT devices. Combining fog and cloud may reduce data transfers and communication bottlenecks to the cloud and also contribute to reduced latencies, as fog computing resources exist closer to the edge. This work examines this IoT-Fog-Cloud ecosystem and provides a literature review from different facets of it: how it can be organized, how management is being addressed, and how applications can benefit from it. Lastly, we present challenging issues yet to be addressed in IoT-Fog-Cloud infrastructures.
Towards a Multi-Tier Fog/Cloud Architecture for Video Streaming
Gama ES, Immich R and Bittencourt LF
2018 IEEE/ACM International Conference on Utility and Cloud Computing Companion (UCC Companion). 2018.
 
Abstract: The video streaming services are already responsible for the majority of the Internet traffic. A good cloud-level architecture partially solves some issues related to the video streaming services. At the same time, however, it introduces new ones such as higher latency and core network congestion. In order to improve on this matter, this work proposes a multi-tier architecture composed of a set of services to video streaming in a fog computing environment. It also takes into consideration classified hierarchical tiers and the ETSI-NFV architecture. The main goal is to design and assess a reliable and high-quality multi-tier services architecture to be used in the Smart City environments. To this end, we introduced a set of video streaming services in the fog/cloud computing, and also proposed how these services may be used to improve the Quality of Experience (QoE) for end-users.
Efficient high-resolution video delivery over VANETs
Immich R, Cerqueira E and Curado M
Wireless Networks. 2018.
 
Abstract: The adoption of video-equipped vehicles in Vehicular ad-hoc networks (VANETs) is experiencing a rapid growth. It is also anticipated a substantial increase in the video content distribution with the arrival of self-driving cars as both passengers and vehicles will be able to produce and consume this type of media. This unveils a set of challenges, especially in VANETs where the network resources tend to be scarce and the connections suffer from time-varying error conditions. Taking everything into consideration, a Quality of Experience (QoE)-driven mechanism is desirable to enhance the video delivery over error-prone networks. To this end, the combined use of forward error correction and unequal error protection has proven its efficiency in delivering high-quality videos with low network overhead. The proposed intelligent quality-driven and network-aware mechanism (AntArmour) uses an ant colony optimization scheme to dynamically allocate a precise amount of redundancy. This allows AntArmour to safeguard, in real-time, the live transmission of high-resolution video streams. This operation is performed according to specific high efficiency video coding details and the actual network conditions such as the signal-to-noise ratio, the network density, the vehicle's position, and the current packet loss rate (PLR) as well as the prediction of future PLR. The experiments were performed using real map's clippings and actual video footage. The assessment was performed with the aid of two well-known objective QoE metrics, as well as the measure of the network overhead. The results showed that the proposed mechanism outperformed all its competitors in both video quality improvement and network overhead decrement.
Avaliação de sistema de streaming de vídeo com cache multi-nível
Omi L, Immich R and Madeira E
Thesis at: Relatório Técnico-IC-PFG UNICAMP. 2018.
 
Abstract: Este trabalho visa analisar os benefıcios da utilizaçao de caches em diferentes camadas da rede para um sistema de streaming de vıdeo. Aproximar o conteúdo ao dispositivo final traz vantagens, no entanto os custos e complexidade da implantaçao de caches podem ser altos, portanto uma análise dos efeitos do cache pode ser útil para a decisao de introduzir um sistema deste tipo. Além disso, a quantidade de dispositivos móveis continua crescendo e o consumo de vıdeo também. Assim, uma simulaçao de uma rede com dispositivos móveis utilizando LTE foi executada, consumindo um serviço de vıdeo com um servidor principal na Cloud e caches na Fog e na Edge e os resultados foram analisados com um foco na Quality of Experience.
Improving Video Delivery with QoE-driven Unequal Protection
Immich R, Cerqueira E and Curado M
Meeting with Science and Technology in Portugal,. 2017.
 
Abstract: The video delivery over wireless networks has risen in popularity in the recent years. However, in order to provide a high quality of experience (QoE) to the end users, it is necessary to deal with several challenges ranging from the fluctuating bandwidth and scarce resources to the high error rates. The use of these error-prone networks unveils the need for an adaptive mechanism to ensure the quality of the delivered video streams. Adaptive forward error correction (FEC) techniques with QoE assurance are desired to protect the stream, preserving the video quality. The adaptive FEC-based mechanism proposed in this article uses several video characteristics and packet loss rate prediction to shield real-time video transmission over static wireless mesh networks, improving both user experience and the usage of resources. This is possible through a combination of a random neural network, to categorise motion intensity of the videos, and an ant colony optimisation scheme, for dynamic redundancy allocation. The benefits and drawbacks are demonstrated through simulations and assessed with QoE metrics, showing that the proposed mechanism outperforms both adaptive and non-adaptive schemes.
Mechanisms for Resilient Video Transmission
Immich R, Cerqueira E and Curado M
Thesis at: University of Coimbra. 2017.
 
Abstract: Wireless networks are envisaged to be one of the most important technologies to provide cost-efficient content delivery, including for video applications. They will allow thousands of thousands of fixed and mobile users to access, produce, share, and consume video content in an ubiquitous way. Real-time video services over these networks are becoming a part of everyday life and have been used to spread information ranging from education to entertainment content. However, the challenge of dealing with the fluctuating bandwidth, scarce resources, and time-varying error rate of these networks, highlights the need for error-resilient video transmission. In this context, the combination of Forward Error Correction (FEC) and Unequal Error Protection (UEP) approaches is known to provide the distribution of video applications for wireless users with Quality of Experience (QoE) assurance. In order to correctly perform the UEP it is necessary to identify the most important parts in the video sequences. To tackle this issue, this thesis proposed a procedure to assess the video characteristics, such as the codec type, the frame type and size, the length and format of the group of pictures as well as the motion vectors, and their related impact on the perceived quality to end-users. Furthermore, as the video content plays an important role on the perceived quality, this thesis also proposes a method to characterise the video’s motion intensity. This involves conducting an exploratory data analysis in bootstrap time and then the use of several techniques in real-time to use the found results. The purpose of the above-mentioned proposals is to give support for the main goal of this thesis, which is to propose mechanisms for resilient video transmission. Taking everything into consideration, this thesis proposes a series of cross-layer video-aware and FEC-based mechanisms with UEP to enhance video transmission in several types of wireless networks. A number of methods to set an adaptive amount of redundancy were used in these mechanisms, such as heuristic techniques, random neural networks, ant colony optimisation, and fuzzy logic. In the first one, heuristic techniques, the mechanisms rely on human experience to define the best strategy. In addition, the aim is not to reach a perfect solution, but a practical one with satisfactory results. In the random neural networks methods, the neurones are trained and validated before run-time until they are able to perform an adequate numeric categorisation. The ant colony optimisation techniques use a defined metaheuristic based on the ant’s pheromones and pre-set rules to compute a precise amount of redundancy. The last one, fuzzy logic techniques, the mechanisms depend on fuzzy rules and sets to find an adequate redundancy ratio. The advantages and drawbacks of the proposed mechanisms were demonstrated in realistic simulations using real video sequences and actual network traces. The assessments were conducted with well-known QoE metrics. The results show that all the proposed mechanisms were able to outperform the competitors on both perceived video quality and network footprint.
Towards a QoE-driven mechanism for improved H.265 video delivery
Immich R, Cerqueira E and Curado M
Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net). 2016.
 
Abstract: The employment of video-equipped vehicles is growing apace. Following the same trend is the number of available applications and services place at disposal in Vehicular Ad-hoc Networks (VANETs). Conversely, video services are commonly referred as one of the most stringent applications, on the grounds that it requires a quality-aware steady and uninterrupted flow of information. Because of that, a number of challenges arose, including how to deal with the scarce network resources, the high-error rates and the time-varying channel conditions. This unveils the need for an adaptive video-aware and Quality of Experience (QoE)-driven mechanism to take care of these challenges and deliver video sequences with good quality. To this end, Forward Error Correction (FEC) techniques can be customized to support video transmissions with QoE assurance over high-mobility and error-prone networks. The adaptive QoE-driven mechanism proposed in this paper improves the resilience of real-time video transmissions against packet losses. It relies on the combination of VANETs characteristics and High Efficiency Video Coding (HEVC) details to provide a tailored amount of redundancy, which improves both the usage of resources and the user experience. The advantages and footprint of the mechanism are evidenced through extensive experiments and QoE assessments, proving that the proposed mechanism outperforms non-adaptive and also adaptive competitors.
QoE-driven video delivery improvement using packet loss prediction
Immich R, Borges P, Cerqueira E and Curado M
International Journal of Parallel, Emergent and Distributed Systems. Taylor & Francis. 2015.
 
Abstract: The video delivery over wireless networks has risen in popularity in the recent years. However, in order to provide a high quality of experience (QoE) to the end users, it is necessary to deal with several challenges ranging from the fluctuating bandwidth and scarce resources to the high error rates. The use of these error-prone networks unveils the need for an adaptive mechanism to ensure the quality of the delivered video streams. Adaptive forward error correction (FEC) techniques with QoE assurance are desired to protect the stream, preserving the video quality. The adaptive FEC-based mechanism proposed in this article uses several video characteristics and packet loss rate prediction to shield real-time video transmission over static wireless mesh networks, improving both user experience and the usage of resources. This is possible through a combination of a random neural network, to categorise motion intensity of the videos, and an ant colony optimisation scheme, for dynamic redundancy allocation. The benefits and drawbacks are demonstrated through simulations and assessed with QoE metrics, showing that the proposed mechanism outperforms both adaptive and non-adaptive schemes.
Adaptive QoE-driven video transmission over Vehicular Ad-hoc Networks
Immich R, Cerqueira E and Curado M
IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS). 2015.
 
Abstract: Vehicular Ad-hoc Networks (VANETs) are envisioned to offer support for a large variety of distributed applications that range from alerting drivers to autonomous driving features and video services. The use of video-equipped vehicles, with support for live transmission, unveils the need for an adaptive Quality of Experience (QoE)-driven mechanism to overcome several challenges and provide a good video quality. These challenges can range from the scarce network resources and vehicles movement to the time-varying channel conditions and high error rates. Adaptive Forward Error Correction (FEC) schemes can be tailored to shield the video transmission with QoE assurance. The adaptive QoE-driven and FEC-based mechanism proposed in the paper safeguard real-time video transmissions over high-mobility and error-prone networks, improving both the usage of resources and the user experience. Benefits and footprint are evidenced through experiments and QoE assessments. The results demonstrate that the proposed mechanism is able to outperform both non-adaptive and adaptive competitors.
Shielding video streaming against packet losses over VANETs
Immich R, Cerqueira E and Curado M
Wireless Networks. 2015.
 
Abstract: Vehicular ad-hoc networks (VANETs) are being widely adopted in the last few years. This type of network enables the utilization of a large diversity of distributed applications, such as road and traffic alerts, autonomous driving capabilities and video distribution. Video applications can be considered one of the most demanding services because it needs a steady and continuous flow of information. This presents a set of challenges to VANETs considering their scarce network resources due to the vehicle movement and time-varying wireless channels. Considering the above mentioned issues, an adaptive quality of experience (QoE)-driven mechanism is needed to provide live transmission capabilities to video-equipped vehicles. This mechanism has to overcome the challenges to grant a high-quality video transmission without adding any unnecessary network overhead. To this end, a forward error correction (FEC) technique can be adapted to enhance the video distribution, leading to higher QoE for end users. The proposed self-adaptive FEC-based mechanism (SHIELD) uses several video characteristics and specific VANETs details to safeguard real-time video streams against packet losses. One of the main contributions of this work is the combined used of network density, signal-to-noise ratio, packet loss rate, and the vehicle's position. This allows SHIELD to better protect the video sequences and enhance the QoE. In doing that, we are able to improve the user experience, while saving network resources. The advantages and drawbacks of the proposed mechanism are demonstrated through extensive experiments and assessed with QoE metrics, proving that it outperforms both adaptive and non-adaptive mechanisms.
Mechanisms for resilient video transmission in wireless networks: Adaptive FEC mechanism with random neural network classification and ant colony optimization
Borges P, Immich R, Cerqueira E and Curado M
Seminario Rede Tematica de Comunicacoes Moveis (RTCM). 2014.
 
Mechanisms for resilient video transmission in wireless networks
Borges PMF, Immich R and Curado M
Thesis at: University of Coimbra. 2014.
 
Abstract: Remote video viewing is largely growing, especially in wireless devices. Therefore, video transmission mechanisms such as retransmission and Forward Error Correction (FEC) are very important to ensure that the video arrives at its destination while retaining its quality. While some of these mechanisms can obtain good performance, this does not mean they provide an optimal situation. There are several factors that negatively impact Quality of Experience (QoE) in video transmission, such as network congestion, loss and type of video being transmitted. Adaptive Forward Error Correction schemes aim at providing protection against loss errors by analysing several relevant characteristics of the video and/or network, and using them to apply unequal error protection (UEP) to di erent parts of the video. Taking this into account, it is clear that an adaptive FEC mechanism is a viable option to achieve optimal error protection, thus increasing the video transmission's resilience against errors and losses, and therefore improving Quality of Experience for the end user. This work presents and examines the state-of-the-art mechanisms for retransmission, FEC, QoE, video classi cation and algorithm optimization. The assessment of the mechanisms presents an in-depth study of each concept and individually explores their advantages and disadvantages. Three mechanisms which provide adaptive FEC are developed in and evaluated in a simulation environment, with motion classi cation, error correction, adaptive redundancy allocation and loss feedback components. The capabilities of the adaptive FEC mechanisms are evaluated through a wireless network environment in order to assess their performance against other methods. The results obtained through the assessed mechanisms showed incremental improvements through each stage of development. They also showed that it is possible to accurately characterize the intensity of motion in video sequences according to their characteristics. Furthermore, the ndings highlight the importance of shielding sequences with higher amounts of motion intensity with greater quantities of redundancy due to david their higher degradation when subjected to error. The mechanisms achieved a considerable reduction in the amount of redundancy used to shield the data being transmitted, particularly the loss prediction mechanism. At the same time, the mechanisms maintained video quality which combined with the overhead reduction results in an overall improvement of QoE ultimately enhancing video transmission in wireless networks.
Adaptive motion-aware FEC-based mechanism to ensure video transmission
Immich R, Borges P, Cerqueira E and Curado M
IEEE Symposium on Computers and Communication (ISCC). 2014.
 
Abstract: Video transmission over wireless networks has shown a great increase in recent years and it is becoming part of our daily life. Meanwhile, several difficulties can impair the success of the transmission, such as limited network resources, high error rates and fluctuating signal strength that may lead to variable bandwidth. Therefore there is the need for adaptive mechanisms that can provide a good video transmission. Adaptive Forward Error Correction (FEC) techniques which assure Quality of Experience (QoE) are a convenient means of delivering video data to wireless users in dynamic and error prone networks, while taking into account the content of the transmitted data. This paper proposes an adaptive content-aware and Random Neural Network (RNN) based mechanism to provide protection of real-time video streams against packet loss in wireless networks, improving user experience and optimising network resources. The benefits of the proposed mechanism are demonstrated through simulations and assessed with QoE metrics.
AntMind: Enhancing error protection for video streaming in wireless networks
Immich R, Borges P, Cerqueira E and Curado M
2014 International Conference on Smart Communications in Network Technologies (SaCoNeT). 2014.
 
Abstract: On-line video services are becoming a large part of the daily routines of people all over the world, where most of the content is accessed through wireless networks. Therefore, it is of ever growing importance that the negative aspects of these types of error prone networks are lessened in order to ensure adequate quality of the delivered video streams. Forward Error Correction (FEC) techniques allow the stream to be protected with an amount of redundancy to preserve the video quality during transmission. Nevertheless, some FEC schemes do not make an efficient usage of the available network resources due to unnecessary use of redundancy as a result of video-unawareness. The adaptive FEC mechanism proposed in this paper uses the motion intensity characteristics of the video and the network loss state to deliver the video streaming with adequate Quality of Experience (QoE), while keeping the use of network resources to a minimum level. It does so from a combined use of a Random Neural Network (RNN) for motion intensity classification and an Ant Colony Optimization (ACO) scheme for dynamic redundancy allocation. QoE metrics are used to assess the performance of the mechanism showing its advantages over adaptive and nonadaptive protection schemes.
Ensuring QoE in wireless networks with adaptive FEC and Fuzzy Logic-based mechanisms
Immich R, Cerqueira E and Curado M
Communications (ICC), 2014 IEEE International Conference on. 2014.
 
Abstract: Online video transmissions over wireless networks are rising in popularity and have already become part of our daily life. In the meantime, it is necessary to address a number of challenges ranging from the scarce resources, time-varying, and high error rates, to the fluctuating bandwidth, unveiling the need for an adaptive mechanism to ensure a good video transmission. Adaptive Forward Error Correction (FEC) techniques with Quality of Experience (QoE) assurance are appropriate to deliver QoE-aware video data to wireless users in dynamic and high error rates networks. This paper proposes an adaptive Video-aware FEC and Fuzzy Logic-based mechanism to shield realtime video transmissions against packet loss in wireless networks, improving both user experience and the usage of resources. The benefits and drawbacks of the proposed mechanism compared with exiting work are demonstrated through simulations and assessed with QoE metrics.
Improving Video QoE in Unmanned Aerial Vehicles Using an Adaptive FEC Mechanism
Immich R, Cerqueira E and Curado M
Wireless Networking for Moving Objects: Protocols, Architectures, Tools, Services and Applications. Springer International Publishing. 2014.
 
Abstract: Unmanned aerial vehicles (UAV) are rising in popularity together with video applications for both military and civilian use. Because of that, it is necessary to address a set of challenges related to the device movement, scarce resources as well as high error rates, making evident the need for an adaptive mechanism to strengthen video transmissions. Adaptive Forward Error Correction (FEC) techniques are known to be suitable to enhance the Quality of Experience (QoE) of video transmitted over error-prone wireless networks with high mobility. This book chapter proposes an adaptive video-aware FEC mechanism that uses motion vectors details to improve real-time UAV video transmissions, providing both higher user experience and better usage of resources. The benefits and drawbacks of the proposed mechanism along with the related work are analysed and put up for test through simulations and evaluated using QoE metrics.
Towards the enhancement of UAV video transmission with motion intensity awareness
Immich R, Cerqueira E and Curado M
2014 IFIP Wireless Days (WD). 2014.
 
Abstract: The use of video-equipped Unmanned Aerial Vehicles (UAV) has been increasing recently, along with the number of available applications for military and civilian employment. This unveils the need for an adaptive video-aware mechanism capable of overcoming a number of challenges related to the scarce network resources, device movement, as well as high error rates, to ensure a good video quality delivery. Forward Error Correction (FEC) techniques can be tailored to provide adaptive protection with Quality of Experience (QoE) assurance over error-prone and high-mobility networks. Besides that, unique characteristics of each video sequence, such as the spatial complexity and the temporal intensity, strongly affect how the QoE will be impacted by the packet loss. This paper proposes an adaptive motion intensity and video-aware FEC mechanism with the aid of Fuzzy logic to safeguard UAV real-time video transmissions against packet loss, providing a better user experience, while saving resources. The advantages and drawbacks of the proposed mechanism in comparison to the related work are evidenced through experiments and assessed by using QoE metrics.
Adaptive video-aware FEC-based mechanism with unequal error protection scheme
Immich R, Cerqueira E and Curado M
Proceedings of the 28th Annual ACM Symposium on Applied Computing. 2013.
 
Abstract: Real-time video services over wireless networks are becoming a part of everyday life and have been used to spread information ranging from education to entertainment content. However, the challenge of dealing with the fluctuating bandwidth, scarce resources and the time-varying error rate of theses networks, unveils the need for an error-resilient video transport. In this context, Forward Error Correction (FEC) approaches are required to provide the distribution of video applications for wireless users with Quality of Experience (QoE) assurance. This work proposes an adaptive cross-layer Video-Aware FEC mechanism with Unequal Error Protection (UEP) scheme to enhance video transmission in wireless networks, while increasing the user satisfaction and improving the usage of wireless resources. The benefit and impact of the proposed mechanism are demonstrated by using simulation and assessed through objective and subjective QoE metrics.
Cross-Layer FEC-Based Mechanism for Packet Loss Resilient Video Transmission
Immich R, Cerqueira E and Curado M
Data Traffic Monitoring and Analysis: From Measurement, Classification, and Anomaly Detection to Quality of Experience. Springer Berlin Heidelberg. 2013.
 
Abstract: Real-time video transmission over wireless networks is now a part of the daily life of users, since it is the vehicle that delivers a wide range of information. The challenge of dealing with the fluctuating bandwidth, scarce resources and time-varying error levels of these networks, reveals the need for packet-loss resilient video transport. Given these conditions, Forward Error Correction (FEC) approaches are desired to ensure the delivery of video services for wireless users with Quality of Experience (QoE) assurance. This work proposes a Cross-layer Video-Aware FEC-based mechanism with Unequal Error Protection (UEP) scheme for packet loss resilient video transmission in wireless networks, which can increase user satisfaction and improve the use of resources. The advantages and disadvantages of the developed mechanism are highlighted through simulations and assessed by means of both subjective and objective QoE metrics.
A quality of experience handover system for heterogeneous multimedia wireless networks
Quadros C, Cerqueira E, Neto A, Pescape A, Riker A, Immich R and Curado M
2013 International Conference on Computing, Networking and Communications (ICNC). 2013.
 
Abstract: The convergence of emerging real-time multimedia services, the increasing coverage of wireless networks and the ever-growing popularity of mobile devices, are leading to an era of user-centric multimedia wireless services. In this scenario, heterogeneous communications will co-exist and ensure that the end-user is always best connected. However, the Quality of Experience (QoE) support for emerging video applications in multi-operator environments remains a significant challenge and is crucial for the success of wireless multimedia systems. This paper presents a Quality of Experience Handover Architecture for Converged Heterogeneous Wireless Networks, called QoEHand. QoEHand allows users of multimedia content to be always best connected in IEEE 802.11e and IEEE 802.16e environments. Simulation results show the impact and benefit of the proposed solution in multi-access and multi-operator wireless scenarios by using objective and subjective QoE metrics.
A QoE handover architecture for converged heterogeneous wireless networks
Rosario D, Cerqueira E, Neto A, Riker A, Immich R and Curado M
Wireless Networks. 2013.
 
Abstract: The convergence of real-time multimedia applications, the increasing coverage of heterogeneous wireless networks and the ever-growing popularity of mobile devices are leading to an era of mobile human-centric multimedia services. In this scenario, heterogeneous communications will co-exist and ensure that the end-user is always best connected. The rigorous networking demands of wireless multimedia systems, beyond quality-oriented control strategies, are necessary to guarantee the best user experience over time. Therefore, the Quality of Experience (QoE) support, especially for 2D or 3D videos in multi-operator environments, remains a significant challenge and is crucial for the success of multimedia systems. This work proposes a QoE Handover Architecture for Converged Heterogeneous Wireless Networks, called QoEHand. QoEHand extends the Media Independent Handover (MIH)/IEEE 802.21 with QoE-awareness, seamless mobility and video adaptation by integrating a set of QoE-based decision-making modules into MIH, namely a video quality estimator, a dynamic class of service mapping and content adaptation schemes. The QoEHand video estimator, mapping and adaptation components operate by coordinating information about video characteristics, available wireless resources in IEEE 802.11e and IEEE 802.16e service classes, and QoE-aware human experience. The video quality estimator works without the need for any decoding, which saves time and minimises processing overheads. Simulations were carried out to show the benefits of QoEHand and its impact on user perception by using objective and subjective QoE metrics.
A parametric QoE video quality estimator for Wireless Networks
Cerqueira E, Neto A, Curado M, Riker A, Immich R, Barros H, Aguiar E and Abelem A
IEEE Globecom Workshops. 2012.
 
Abstract: The development of real-time quality estimator schemes for emerging Internet videos with different content types remains a significant challenge and is crucial for the success of wireless multimedia systems. However, currently in-service assessment schemes fail in capturing subjective aspects of multimedia content related to the user perception. Therefore, this paper proposes an on-the-fly parametric video quality estimator approach (called MultiQoE) for real-time video streaming applications. Experiments in a Wireless Mesh Network (WMN) scenario were carried out to show the accuracy, benefit, and impact of MultiQoE compared to widely used Quality of Experience (QoE) subjective, objective and parametric methods.
A mobile QoE Architecture for Heterogeneous Multimedia Wireless Networks
Quadros C, Cerqueira E, Neto A, Riker A, Immich R and Curado M
2012 IEEE Globecom Workshops. 2012.
 
Abstract: One of the main requirements in this emerging wireless multimedia era is the Quality of Experience (QoE) assurance for 2D or 3D video applications in heterogeneous multi-operator environments. Therefore, this paper proposes a QoE Architecture for Heterogeneous Multimedia Wireless Networks, called QoEHand. QoEHand extends the Media Independent Handover (MIH)/IEEE 802.21 proposal with QoE-awareness, seamless mobility, dynamic class of service mapping and a set of content adaptation schemes. The proposed solution allows the best connection and considers the QoE needs of mobile clients and available wireless resources in IEEE 802.11e and IEEE 802.16e service classes. Simulation experiments were carried out to show the impact and benefits of QoEHand on the user's perception, by using objective and subjective QoE metrics.
QoE-aware FEC mechanism for intrusion detection in multi-tier Wireless Multimedia Sensor Networks
Zhao Z, Braun T, do Rosario D, Cerqueira E, Immich R and Curado M
IEEE 8th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob). 2012.
 
Abstract: Wireless Multimedia Sensor Networks (WMSNs) play an important role in pervasive and ubiquitous systems. The multimedia content in such networks has the potential of enhancing the level of information collected, enlarging the range of coverage, and enabling multi-view support. For WMSN applications, the multi-tier network architecture has proven to be more beneficial than a single-tier in terms of energy-efficiency, scalability, functionality and reliability. In this context, a multimedia intrusion detection application appears as a promising application of multi-tier WMSNs, where the lower tier can detect the intruder using scalar sensors, and the higher tier camera nodes will be woken up to send real time video sequences from the detected area. The transmission of multimedia content requires a certain quality level from the user perspective, while energy consumption and network overhead should be minimized. Among the existing mechanisms for improving video transmissions, Forward Error Correction (FEC) can be regarded as a suitable solution to improve video quality level from the user point-of-view. In this work, we propose a Quality of Experience (QoE)-aware FEC mechanism for WMSNs, which creates redundant packets based on impact of the frame on the user experience. According to the simulation results, our proposed mechanism achieved similar video quality level compared with standard FEC, while reducing the transmission of redundant packets, which will bring many benefits in a resource-constrained system.
Gerenciamento Eficiente de Recursos em Sistemas Embarcados
Immich R, Kreutz DL and Frohlich AA
Latin American Computing Conference (CLEI). 2006.
 
Abstract: Estratégias clássicas de gerenciamento de recursos em sistemas operacionais são complexas e inapropriadas para sistemas embarcados. Muitas vezes, as implementações utilizam métodos virtuais(polimorfismo), com o objetivo de alcançar transparência e reusabilidade de código, e/ou longas estruturas condicionais, que invariavelmente ocupam blocos de memória e processamento desnecessariamente, o que pode não ser aceitável em sistemas embarcados. O gerenciamento de recursos no EPOS(Embedded Parallel Operating System), é realizado de forma transparente a aplicação, flexível e sem adicionar sobrecarga desnecessária ao sistema. Através da utilização da técnica de metaprogramação estática é possível predizer em tempo de compilação se haverá necessidade da utilização de polimorfismo, ou se estes poderão ser substituídos por chamadas diretas. Dessa forma, somente serão utilizadas chamadas indiretas quando necessário, provendo economia de recursos. A utilização desta técnica mostrou-se uma alternativa viável para sistemas embarcados, provando que é possível utilizá-la isoladamente no sistema, continuando com a flexibilidade original e provendo as otimizações necessárias.
Resource management for embedded systems
Immich R, Kreutz DL and Frohlich AA
IEEE International Workshop on Factory Communication Systems. 2006.
 
Abstract: Classical strategies for resource management in operating systems are often complex and innapropriate for embedded systems. Implementations for these strategies may use either virtual function tables or long conditional structures to provide transparent access to different resources. This overhead is unacceptable for embedded systems. The EPOS operating system provides flexible and transparent access to resources for applications without incurring in unnecessary overhead. Metaprogrammed structures are used to predict, according to application usage and in compile time, whether a resource must use a polymorphic representation or may be accessed through direct calls. This way, virtual function tables are only used in the system when strictly necessary, and thus saving resources. In this article, we show that this strategy is a viable alternative for resource management in embedded systems.
Modelo de um Nucleo de Sistema Operacional Extensivel utilizando reflexao computacional
Immich R and Zancanella LC
Thesis at: Federal University of Santa Catarina. 2006.
 
Abstract: A concepção de computadores cada vez mais poderosos, com mais recursos e funcionalidades impulsionou uma significativa evolução no desenvolvimento de sistemas operacionais. Estes sistemas, com o objetivo de prover acesso aos dispositivos, implementam uma complexa abstração do hardware, permitindo que as aplicações sejam projetadas em uma camada de alto nível, facilitando o desenvolvimento e aumentando a portabilidade. Esta abordagem é eficiente nos casos citados acima, porém ela produz um gerenciador de recursos fortemente centralizado, que pode entrar em conflito com as necessidades específicas das aplicações, limitando-as tanto em performance quanto em flexibilidade, devido ao fato de que a aplicação precisa se adaptar ao ambiente de execução. De acordo com autores conceituados, a necessidade da adaptação do sistema operacional em relação a aplicação é cada vez mais evidente e somente desta forma será possível oferecer um ambiente especializado de acordo com as necessidades específicas de cada uma delas. O modelo proposto neste trabalho, visa suprir estas necessidades, oferecendo a possibilidade da modificação do ambiente de execução através de meta-informações passadas pelas aplicações no momento da sua inicialização ou dinamicamente durante a sua execução. Através das simulações realizadas, foi provado que é possível a concepção de tal arquitetura, contudo ainda é muito dependente de recursos que estão sendo desenvolvidos e aprimorados, como a máquina virtual Java.
Gerenciamento de Energia em Sistemas de Sensoriamento Remoto
Junior ASH, Wanner LF, de Oliveira AB, Immich R and Fröhlich AA
Third Brazilian Workshop on Operating System. 2006.
 
Abstract: Remote sensing systems usually are simple, battery-powered systems with resource limitations. In some situations, their batteries lifetime becomes a primordial factor for reliability. Because of this, it is very important to handle power consumption of such devices in a non-restrictive and low-overhead way. In this paper we propose a simplified interface for application-driven power management of software and hardware components in a hierarchically organized, component-based operating system. This method allowed power management of system components without the need for costly techniques or strategies. A case study which implements a thermometer for indoor environments showed energy savings of almost 40% by just allowing applications to express when certain components are not being used.
Created by JabRef on 08/03/2023.

Contact info

Roger Immich
Instituto Metrópole Digital (IMD)
CIVT - UFRN - Av. Senador Salgado Filho, 3000, Lagoa Nova
CEP 59078-970 - Natal/RN
5°49'54.2"S 35°12'19.9"W
-5.831725, -35.205538
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