Cesar Zeferino - Academia.edu (original) (raw)
Papers by Cesar Zeferino
O filtro de difusao anisotropica e uma tecnica de filtragem de ruidos utilizada no pre-processame... more O filtro de difusao anisotropica e uma tecnica de filtragem de ruidos utilizada no pre-processamento de imagens digitais. Esse filtro utiliza operadores complexos e tem um alto custo computacional de forma que coprocessadores podem ser utilizados para acelerar a sua execucao. Nesse contexto, neste trabalho foi realizada a integracao de um coprocessador do filtro de difusao anisotropica implementado em um sistema integrado em FPGA. O sistema inclui ainda um coprocessador ARM com interface de comunicacao para um computador pessoal. Foi realizada a exploracao de paralelismo na implementacao do coprocessador, bem como a comparacao com o desempenho de implementacoes por software executadas no ARM e no computador pessoal. Os resultados demonstraram que o coprocessador consegue obter tempos de processamento menores que os dos demais processadores, mesmo trabalhando a frequencias de operacao bem inferiores.
Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement... more Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement with greater strength and endurance, being used in several application areas, such as industry and medicine. In this context, this paper presents the development of a hybrid control method for exoskeletons, combining admission and impedance control based on electromyographic input signals. A proof of concept of a robotic arm with two degrees of freedom, mimicking the functions of a human's upper limb, was built to evaluate the proposed control system. Through tests that measured the discrepancy between the angles of the human joint and the joint of the exoskeleton, it was possible to determine that the system remained within an acceptable error range. The average error is lower than 4.3%, and the robotic arm manages to mimic the movements of the upper limbs of a human in real-time.
The LEON processor is a softcore for space applications that was developed by the European Space ... more The LEON processor is a softcore for space applications that was developed by the European Space Agency (ESA). It is part of the GRLIB IP library, which allows the building of systems composed of IPs and custom components. The interconnection of components in a LEON3-based system is performed by means of the ARM AMBA 2.0 bus, using the AHB protocol for the high-performance cores and the APB protocol for peripherals. However, bus architecture does not meet the communication requirements of systems composed of dozens of cores, and the Network-on-Chip approach is used to overcome this limitation. In this context, this work describes the implementation of different LEON3-based systems and the necessary adaptations to integrate the processing cores to a Network-on-Chip.
The constant reduction in the size of components of integrated circuits, as well as the growing o... more The constant reduction in the size of components of integrated circuits, as well as the growing operating frequency, increases the vulnerability to internal and external noise sources. These noises can cause a failure in any component, affecting the functioning of the system as a whole. Future Systems-on-Chip with dozens of cores will be based on Networks-on-Chip (NoCs), and will require networks that are able to detect a failure and avoid that this failure leads to a system failure and an application malfunction. In this context, this work aims at evaluating solutions to increase the reliability and availability of a SoCIN NoC, implementing mechanisms for error detection and correction on that network. The implemented mechanisms added a silicon overhead of 35,47% and a power dissipation overhead of 6,46% when compared to the original router. Keywords— System-on-Chip, Network-on-Chip, Faulttolerance, Error model, Single-event Upset
IoT is an emerging area in which we expect to have billions of devices connected to the Internet ... more IoT is an emerging area in which we expect to have billions of devices connected to the Internet by 2020. IoT applications can offer many benefits to environments, society and the economy through the interconnection and cooperation of smart objects. However, there are many privacy challenges, such as authentication, authorization, and confidentiality of personal data. With this in mind, we have developed a solution for managing user profiles based on privacy and evolution. For that, we define the criteria and characteristics for each environment. The contribution of the work also applies to the evolution of the UbiPri Middleware, with a module implemented and tested according to the rules of environments so that they can modify the user's profile over time according to their frequency in the environment. The modified profile can be raised, reduced and blocked. This implementation has been validated using scripts that perform probabilistic simulation and user authentication. From...
As Redes-em-Chip sao a infraestrutura de comunicacao adotada nos sistemas many-core atuais e dive... more As Redes-em-Chip sao a infraestrutura de comunicacao adotada nos sistemas many-core atuais e diversos estudos tem comparado o desempenho de arquiteturas de rede. Porem, esses trabalhos carecem de analises quantitativas ou de abrangencia arquitetural. Para superar essas limitacoes, este artigo apresenta uma biblioteca de componentes de simulacao que possibilita a modelagem de diferentes alternativas arquiteturais e a coleta de dados para uma comparacao quantitativa. Um amplo conjunto de experimentos foi realizado para demonstrar a efetividade da biblioteca implementada. Os resultados obtidos permitem identificar as melhores alternativas de rede para diferentes cenarios de trafego.
... The recently released HA OSCAR software stack is an effort that makes inroads here.HA OSCAR d... more ... The recently released HA OSCAR software stack is an effort that makes inroads here.HA OSCAR deals with availability and fault issues at the master node with multi head failover architecture and service level fault tolerance mechanisms. ...
This work presents a simulation model for point-to-point transmission of encrypted data using the... more This work presents a simulation model for point-to-point transmission of encrypted data using the application layer of Open Smart Grid Protocol (OSGP). The simulation aims to verify the integrity of the data transmitted from one point to another using Power Line Communication (PLC). The simulation model was developed in MATLAB and uses RSA, AES, RC-6, and 3-DES cryptographies to encode data. Data transmission uses PLC technique with Gaussian Minimmum Shift Key (GMSK) modulation. Results demonstrate that it is possible to use the OSGP protocol in the application layer with different criteria, which can be used according to the data size. It was applied a Additive White Gaussian Noise (AWGN) in the transmission to simulate the effects that exist in a real network. The experiments demonstrate that RC-6 outperforms the other cryptographic algorithms, presenting the smallest execution time, with low memory requirements.
Systems for harsh environments often use embedded processors for tasks that require reliability. ... more Systems for harsh environments often use embedded processors for tasks that require reliability. However, harsh environments cause faulty behavior in electronics, which eventually lead to system failure. Therefore, embedded processors must use techniques to improve their reliability. In this context, this work presents the implementation and characterization of a RISC-V-based system-on-chip. We characterized our implementation by carrying out test campaigns at the ChipIr irradiation facility. This facility provides a beamline for testing electronics against neutrons, mimicking atmospheric-like environments. With this first test campaign, we identified the most critical parts of our system-on-chip and essential tips to improve the test effectiveness. In the second test campaign, we used an improved version of the system setup with higher reliability error observability features. The version embedding all the hardening techniques could correct or mitigate 98.1 % of the detected upsets...
2019 17th International Conference on Privacy, Security and Trust (PST)
Over the past decade, smart crime-fighting solutions have been adopted by the major cities around... more Over the past decade, smart crime-fighting solutions have been adopted by the major cities around the world. In this context, license plate recognition (LPR) systems have been used by public safety forces to monitor vehicle movement. However, current systems store vehicle location data indistinctly, without differentiating vehicles that are under criminal investigation from those that are not. This monitoring may be used to infer personal data about the owner of the vehicle, resulting in a violation of privacy by disregarding data protection laws. This paper presents a study about the use of technologies to ensure privacy in the Internet of Things and proposes a model to protect data collected by LPR systems. Our solution uses private blockchains regulated by smart contracts to ensure that the storage of data complies with current data protection laws.
IEEE Latin America Transactions
2020 15th Design & Technology of Integrated Systems in Nanoscale Era (DTIS)
Embedded processors have been used in a diversity of applications, such as consumer electronics, ... more Embedded processors have been used in a diversity of applications, such as consumer electronics, home appliances, and automation systems. Another area that embedded processors can be adopted is space systems, which demand faulttolerant components to deal with the environmental hostility. This work presents a low-cost fault-tolerant implementation of the RISC-V architecture, an emerging open industry standard for the building of embedded processors. The proposed implementation employs physical and information redundancy to reduce error propagation, with competitive silicon and power overheads when comparing with other RISC-V implementations.
Applied Sciences
Since the early 2000s, life in cities has changed significantly due to the Internet of Things (Io... more Since the early 2000s, life in cities has changed significantly due to the Internet of Things (IoT). This concept enables developers to integrate different devices collecting, storing, and processing a large amount of data, enabling new services to improve various professional and personal activities. However, privacy issues arise with a large amount of data generated, and solutions based on blockchain technology and smart contract have been developed to address these issues. Nevertheless, several issues must still be taken into account when developing blockchain architectures aimed at the IoT scenario because security flaws still exist in smart contracts, mainly due to the lack of ease when building the code. This article presents a blockchain storage architecture focused on license plate recognition (LPR) systems for smart cities focusing on privacy, performance, and security. The proposed architecture relies on the Ethereum platform. Each smart contract matches the privacy prefer...
Journal of Sensor and Actuator Networks
Cryptography is considered indispensable among security measures applied to data concerning insec... more Cryptography is considered indispensable among security measures applied to data concerning insecure means of transmission. Among various existent algorithms on asymmetric cryptography, we may cite Elliptic Curve Cryptography (ECC), which has been widely used due to its security level and reduced key sizes. When compared to Rivest, Shamir and Adleman (RSA), for example, ECC can maintain security levels with a shorter key. Elliptic Curve Point Multiplication (ECPM) is the main function in ECC, and is the component with the highest hardware cost. Lots of ECPM implementations have been applied on hardware targeting the acceleration of its calculus. This article presents a systematic review of literature on ECPM implementations on both Field-Programmable Gate Array (FPGA) and Application-Specific Integrated Circuit (ASIC). The obtained results show which methods and technologies have been used to implement ECPM on hardware and present some findings of the choices available to the hardwa...
Microelectronics Reliability
IEEE Latin America Transactions
Anais do XXXVI Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC 2018)
Este artigo descreve um mecanismo de verificação que aproveita os recursos do BIOS UEFI para ates... more Este artigo descreve um mecanismo de verificação que aproveita os recursos do BIOS UEFI para atestar a integridade de software de sistemas embarcados utilizados na Internet das Coisas. Este mecanismo tem como componente principal uma aplicação, chamada AVIS UEFI, executada na fase de Aplicativos de Pré-Boot da inicialização que utiliza assinatura digital e chaves armazenadas em um dispositivo criptográfico para verificar se o software foi adulterado. De acordo com o resultado da verificação de integridade, o sistema é inicializado ou desligado. Como prova de conceito, um protótipo foi desenvolvido e avaliado considerando um estudo de caso real. Os resultados obtidos demonstram a viabilidade técnica do mecanismo.
Anais do XII Computer on the Beach - COTB '21
ABSTRACTComputer processors provide an abstract model known as theinstruction set architecture, w... more ABSTRACTComputer processors provide an abstract model known as theinstruction set architecture, which serves as an interface betweenthe available hardware and the software. Application developersneed to communicate with these types of hardware, and having tolearn each computer specification is difficult and time-consuming.Operating systems provide an abstraction towards the availablecomputer hardware and user software. They manage computerresources to enable application programmers to communicate withthe available hardware. This work introduces an academic-orientedoperating system for the RISC-V architecture, a de facto instructionset architecture standard, and compares the solution with othersmall operating systems using the same architecture. As the maincontribution, this work provides an extensible operating system tointroduce students to operating system development.
Electronics
Smart environments are pervasive computing systems that provide higher comfort levels on daily ro... more Smart environments are pervasive computing systems that provide higher comfort levels on daily routines throughout interactions among smart sensors and embedded computers. The lack of privacy within these interactions can lead to the exposure of sensitive data. We present PRIPRO (PRIvacy PROfiles), a management tool that includes an Android application that acts on the user’s smartphone by allowing or blocking resources according to the context, in order to address this issue. Back-end web server processes and imposes a protocol according to the conditions that the user selected beforehand. The experimental results show that the proposed solution successfully communicates with the Android Device Administration framework, and the device appropriately reacts to the expected set of permissions imposed according to the user’s profile with low response time and resource usage.
O filtro de difusao anisotropica e uma tecnica de filtragem de ruidos utilizada no pre-processame... more O filtro de difusao anisotropica e uma tecnica de filtragem de ruidos utilizada no pre-processamento de imagens digitais. Esse filtro utiliza operadores complexos e tem um alto custo computacional de forma que coprocessadores podem ser utilizados para acelerar a sua execucao. Nesse contexto, neste trabalho foi realizada a integracao de um coprocessador do filtro de difusao anisotropica implementado em um sistema integrado em FPGA. O sistema inclui ainda um coprocessador ARM com interface de comunicacao para um computador pessoal. Foi realizada a exploracao de paralelismo na implementacao do coprocessador, bem como a comparacao com o desempenho de implementacoes por software executadas no ARM e no computador pessoal. Os resultados demonstraram que o coprocessador consegue obter tempos de processamento menores que os dos demais processadores, mesmo trabalhando a frequencias de operacao bem inferiores.
Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement... more Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement with greater strength and endurance, being used in several application areas, such as industry and medicine. In this context, this paper presents the development of a hybrid control method for exoskeletons, combining admission and impedance control based on electromyographic input signals. A proof of concept of a robotic arm with two degrees of freedom, mimicking the functions of a human's upper limb, was built to evaluate the proposed control system. Through tests that measured the discrepancy between the angles of the human joint and the joint of the exoskeleton, it was possible to determine that the system remained within an acceptable error range. The average error is lower than 4.3%, and the robotic arm manages to mimic the movements of the upper limbs of a human in real-time.
The LEON processor is a softcore for space applications that was developed by the European Space ... more The LEON processor is a softcore for space applications that was developed by the European Space Agency (ESA). It is part of the GRLIB IP library, which allows the building of systems composed of IPs and custom components. The interconnection of components in a LEON3-based system is performed by means of the ARM AMBA 2.0 bus, using the AHB protocol for the high-performance cores and the APB protocol for peripherals. However, bus architecture does not meet the communication requirements of systems composed of dozens of cores, and the Network-on-Chip approach is used to overcome this limitation. In this context, this work describes the implementation of different LEON3-based systems and the necessary adaptations to integrate the processing cores to a Network-on-Chip.
The constant reduction in the size of components of integrated circuits, as well as the growing o... more The constant reduction in the size of components of integrated circuits, as well as the growing operating frequency, increases the vulnerability to internal and external noise sources. These noises can cause a failure in any component, affecting the functioning of the system as a whole. Future Systems-on-Chip with dozens of cores will be based on Networks-on-Chip (NoCs), and will require networks that are able to detect a failure and avoid that this failure leads to a system failure and an application malfunction. In this context, this work aims at evaluating solutions to increase the reliability and availability of a SoCIN NoC, implementing mechanisms for error detection and correction on that network. The implemented mechanisms added a silicon overhead of 35,47% and a power dissipation overhead of 6,46% when compared to the original router. Keywords— System-on-Chip, Network-on-Chip, Faulttolerance, Error model, Single-event Upset
IoT is an emerging area in which we expect to have billions of devices connected to the Internet ... more IoT is an emerging area in which we expect to have billions of devices connected to the Internet by 2020. IoT applications can offer many benefits to environments, society and the economy through the interconnection and cooperation of smart objects. However, there are many privacy challenges, such as authentication, authorization, and confidentiality of personal data. With this in mind, we have developed a solution for managing user profiles based on privacy and evolution. For that, we define the criteria and characteristics for each environment. The contribution of the work also applies to the evolution of the UbiPri Middleware, with a module implemented and tested according to the rules of environments so that they can modify the user's profile over time according to their frequency in the environment. The modified profile can be raised, reduced and blocked. This implementation has been validated using scripts that perform probabilistic simulation and user authentication. From...
As Redes-em-Chip sao a infraestrutura de comunicacao adotada nos sistemas many-core atuais e dive... more As Redes-em-Chip sao a infraestrutura de comunicacao adotada nos sistemas many-core atuais e diversos estudos tem comparado o desempenho de arquiteturas de rede. Porem, esses trabalhos carecem de analises quantitativas ou de abrangencia arquitetural. Para superar essas limitacoes, este artigo apresenta uma biblioteca de componentes de simulacao que possibilita a modelagem de diferentes alternativas arquiteturais e a coleta de dados para uma comparacao quantitativa. Um amplo conjunto de experimentos foi realizado para demonstrar a efetividade da biblioteca implementada. Os resultados obtidos permitem identificar as melhores alternativas de rede para diferentes cenarios de trafego.
... The recently released HA OSCAR software stack is an effort that makes inroads here.HA OSCAR d... more ... The recently released HA OSCAR software stack is an effort that makes inroads here.HA OSCAR deals with availability and fault issues at the master node with multi head failover architecture and service level fault tolerance mechanisms. ...
This work presents a simulation model for point-to-point transmission of encrypted data using the... more This work presents a simulation model for point-to-point transmission of encrypted data using the application layer of Open Smart Grid Protocol (OSGP). The simulation aims to verify the integrity of the data transmitted from one point to another using Power Line Communication (PLC). The simulation model was developed in MATLAB and uses RSA, AES, RC-6, and 3-DES cryptographies to encode data. Data transmission uses PLC technique with Gaussian Minimmum Shift Key (GMSK) modulation. Results demonstrate that it is possible to use the OSGP protocol in the application layer with different criteria, which can be used according to the data size. It was applied a Additive White Gaussian Noise (AWGN) in the transmission to simulate the effects that exist in a real network. The experiments demonstrate that RC-6 outperforms the other cryptographic algorithms, presenting the smallest execution time, with low memory requirements.
Systems for harsh environments often use embedded processors for tasks that require reliability. ... more Systems for harsh environments often use embedded processors for tasks that require reliability. However, harsh environments cause faulty behavior in electronics, which eventually lead to system failure. Therefore, embedded processors must use techniques to improve their reliability. In this context, this work presents the implementation and characterization of a RISC-V-based system-on-chip. We characterized our implementation by carrying out test campaigns at the ChipIr irradiation facility. This facility provides a beamline for testing electronics against neutrons, mimicking atmospheric-like environments. With this first test campaign, we identified the most critical parts of our system-on-chip and essential tips to improve the test effectiveness. In the second test campaign, we used an improved version of the system setup with higher reliability error observability features. The version embedding all the hardening techniques could correct or mitigate 98.1 % of the detected upsets...
2019 17th International Conference on Privacy, Security and Trust (PST)
Over the past decade, smart crime-fighting solutions have been adopted by the major cities around... more Over the past decade, smart crime-fighting solutions have been adopted by the major cities around the world. In this context, license plate recognition (LPR) systems have been used by public safety forces to monitor vehicle movement. However, current systems store vehicle location data indistinctly, without differentiating vehicles that are under criminal investigation from those that are not. This monitoring may be used to infer personal data about the owner of the vehicle, resulting in a violation of privacy by disregarding data protection laws. This paper presents a study about the use of technologies to ensure privacy in the Internet of Things and proposes a model to protect data collected by LPR systems. Our solution uses private blockchains regulated by smart contracts to ensure that the storage of data complies with current data protection laws.
IEEE Latin America Transactions
2020 15th Design & Technology of Integrated Systems in Nanoscale Era (DTIS)
Embedded processors have been used in a diversity of applications, such as consumer electronics, ... more Embedded processors have been used in a diversity of applications, such as consumer electronics, home appliances, and automation systems. Another area that embedded processors can be adopted is space systems, which demand faulttolerant components to deal with the environmental hostility. This work presents a low-cost fault-tolerant implementation of the RISC-V architecture, an emerging open industry standard for the building of embedded processors. The proposed implementation employs physical and information redundancy to reduce error propagation, with competitive silicon and power overheads when comparing with other RISC-V implementations.
Applied Sciences
Since the early 2000s, life in cities has changed significantly due to the Internet of Things (Io... more Since the early 2000s, life in cities has changed significantly due to the Internet of Things (IoT). This concept enables developers to integrate different devices collecting, storing, and processing a large amount of data, enabling new services to improve various professional and personal activities. However, privacy issues arise with a large amount of data generated, and solutions based on blockchain technology and smart contract have been developed to address these issues. Nevertheless, several issues must still be taken into account when developing blockchain architectures aimed at the IoT scenario because security flaws still exist in smart contracts, mainly due to the lack of ease when building the code. This article presents a blockchain storage architecture focused on license plate recognition (LPR) systems for smart cities focusing on privacy, performance, and security. The proposed architecture relies on the Ethereum platform. Each smart contract matches the privacy prefer...
Journal of Sensor and Actuator Networks
Cryptography is considered indispensable among security measures applied to data concerning insec... more Cryptography is considered indispensable among security measures applied to data concerning insecure means of transmission. Among various existent algorithms on asymmetric cryptography, we may cite Elliptic Curve Cryptography (ECC), which has been widely used due to its security level and reduced key sizes. When compared to Rivest, Shamir and Adleman (RSA), for example, ECC can maintain security levels with a shorter key. Elliptic Curve Point Multiplication (ECPM) is the main function in ECC, and is the component with the highest hardware cost. Lots of ECPM implementations have been applied on hardware targeting the acceleration of its calculus. This article presents a systematic review of literature on ECPM implementations on both Field-Programmable Gate Array (FPGA) and Application-Specific Integrated Circuit (ASIC). The obtained results show which methods and technologies have been used to implement ECPM on hardware and present some findings of the choices available to the hardwa...
Microelectronics Reliability
IEEE Latin America Transactions
Anais do XXXVI Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC 2018)
Este artigo descreve um mecanismo de verificação que aproveita os recursos do BIOS UEFI para ates... more Este artigo descreve um mecanismo de verificação que aproveita os recursos do BIOS UEFI para atestar a integridade de software de sistemas embarcados utilizados na Internet das Coisas. Este mecanismo tem como componente principal uma aplicação, chamada AVIS UEFI, executada na fase de Aplicativos de Pré-Boot da inicialização que utiliza assinatura digital e chaves armazenadas em um dispositivo criptográfico para verificar se o software foi adulterado. De acordo com o resultado da verificação de integridade, o sistema é inicializado ou desligado. Como prova de conceito, um protótipo foi desenvolvido e avaliado considerando um estudo de caso real. Os resultados obtidos demonstram a viabilidade técnica do mecanismo.
Anais do XII Computer on the Beach - COTB '21
ABSTRACTComputer processors provide an abstract model known as theinstruction set architecture, w... more ABSTRACTComputer processors provide an abstract model known as theinstruction set architecture, which serves as an interface betweenthe available hardware and the software. Application developersneed to communicate with these types of hardware, and having tolearn each computer specification is difficult and time-consuming.Operating systems provide an abstraction towards the availablecomputer hardware and user software. They manage computerresources to enable application programmers to communicate withthe available hardware. This work introduces an academic-orientedoperating system for the RISC-V architecture, a de facto instructionset architecture standard, and compares the solution with othersmall operating systems using the same architecture. As the maincontribution, this work provides an extensible operating system tointroduce students to operating system development.
Electronics
Smart environments are pervasive computing systems that provide higher comfort levels on daily ro... more Smart environments are pervasive computing systems that provide higher comfort levels on daily routines throughout interactions among smart sensors and embedded computers. The lack of privacy within these interactions can lead to the exposure of sensitive data. We present PRIPRO (PRIvacy PROfiles), a management tool that includes an Android application that acts on the user’s smartphone by allowing or blocking resources according to the context, in order to address this issue. Back-end web server processes and imposes a protocol according to the conditions that the user selected beforehand. The experimental results show that the proposed solution successfully communicates with the Android Device Administration framework, and the device appropriately reacts to the expected set of permissions imposed according to the user’s profile with low response time and resource usage.