Recently there has been an increase of interest in implementing a new set of home energy manageme... more Recently there has been an increase of interest in implementing a new set of home energy management devices that integrate Information Technologies, the Internet of Things and the ability tocommunicatebetween several appliances. Such energy management devices constitute an important milestone on the path to the Smart Grid, by being able to perform load-scheduling, taking into consideration different variables, such as the forecasted power generation from renewable sources, different tariffs' rates, electric circuit constraints, user restrictions and correspondent comfort levels. To achieve it, they are required to maintain machine-to-machine communications with home appliances, while performing human-computer interaction through simple and intuitive solutions. In order to improve user experience when interacting with such devices, several depth and movement sensors are currently available thatenable humans to interact with machines in innovative ways. In this paper, a 3D gesture recognition solution is explored, showingthatwhen combined with 2D and 3D representations of building, objectsand menus, allow humans to interact intuitively with energy management devices, in a way that cannot be achieved with other interface paradigms.
The first major step in training an object detection model to different classes from the availabl... more The first major step in training an object detection model to different classes from the available datasets is the gathering of meaningful and properly annotated data. This recurring task will determine the length of any project, and, more importantly, the quality of the resulting models. This obstacle is amplified when the data available for the new classes are scarce or incompatible, as in the case of fish detection in the open sea. This issue was tackled using a mixed and reversed approach: a network is initiated with a noisy dataset of the same species as our classes (fish), although in different scenarios and conditions (fish from Australian marine fauna), and we gathered the target footage (fish from Portuguese marine fauna; Atlantic Ocean) for the application without annotations. Using the temporal information of the detected objects and augmented techniques during later training, it was possible to generate highly accurate labels from our targeted footage. Furthermore, the d...
2020 IEEE 14th International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), 2020
This paper presents and describes switched-capacitor DC-DC combination converters with a single i... more This paper presents and describes switched-capacitor DC-DC combination converters with a single input and multiple outputs, with step-down and step-up voltage ratios. The combination converters provide two or three different DC outputs (depending on the combination), with different conversion ratios. The main advantage of the proposed converters is the low number of components used in the combination (two-output configurations require two link capacitors, and three-output configurations require three link capacitors) and two complementary phase clocks, which may reduce size and manufacturing costs for many applications. The DC-DC combination converters are designed to be fully integrated, and were implemented in a 65nm CMOS technology. The analysis of the proposed configurations for different performance modes and load conditions is presented, and simulation results show that these combination converter topologies are suitable for multiple-output switched-capacitor DC-DC converters with multiple conversion ratios.
As the number of Plug-In Electric Vehicles continues to rise, existing electrical grids need to a... more As the number of Plug-In Electric Vehicles continues to rise, existing electrical grids need to adapt to support the expected charging demand of such vehicles. Fortunately, a growing number of renewable energy sources are also being introduced in current electrical grids, reducing the dependency on fossil fuels. Leveraged by the self-consumption legislation in several countries, the introduction of renewable energy sources continue to happen well beyond the end of the feed-in tariff rates. However, due to their variable nature, renewable energy sources are frequently characterized as intermittent resources, which cause mismatches in the required equilibrium between production and demand. In this scenario, the role of end users is very important, since they are not only required to participate in energy generation - becoming the so-called prosumers – but also they should allow the adjustment of the consumption, according with the generation levels. Plug-In Electric Vehicles, due to t...
In this paper a comparative analysis of the tracking efficiency reported by two tracking systems ... more In this paper a comparative analysis of the tracking efficiency reported by two tracking systems of the maximum power point (MPPT) of a photovoltaic (PV) generator is carried out.
The work developed consists in an aging-aware dynamic voltage or frequency scaling methodology, t... more The work developed consists in an aging-aware dynamic voltage or frequency scaling methodology, to be used in long-term operation, using global and local performance sensors. Methodology allows circuits to be dynamically optimized, during their lifetime , according with one of two possible needs: (1) restrict power consumption, by reducing power-supply voltage to the minimum value that prevents errors from happening; or (2) optimize performance, by increasing operating frequency to the maximum limit that prevents errors' occurrence. The dynamic optimization is achieved by using a cooperative work of global and local sensors. Moreover, a new local sensor is presented, to obtain an enhanced solution with additional tolerance to delayfaults, allowing to achieve higher improvement in power or frequency optimization, or to achieve a higher safety and control margin. Spice simulations in a 65nm CMOS technology demonstrate the results for an example of a dynamic frequency scaling strategy.
The low power quest in CMOS integrated circuits is pushing power-supply voltages to enter the sub... more The low power quest in CMOS integrated circuits is pushing power-supply voltages to enter the subthreshold levels. The drastic power savings obtained in subthreshold voltage operation makes this an important technique to be used in battery-operated devices. However, working at subthreshold power-supply voltages, frequency operation has to be reduced, making Dynamic Voltage and Frequency Scaling (DVFS) methodologies hard to implement. In fact, existing solutions use wide safety margins and DVFS are typically implemented with static and pre-defined steps, both for the supply-voltage or the clock frequency. But changes in VDD and in clock frequency impose additional challenges, as delay faults may arise, especially in nanometer technologies. Moreover, when a PVTA (Process, power-supply Voltage, Temperature and Aging) variation occurs, circuit performance is affected and circuits are more prone to have delay-faults, especially when cumulative degradations pile up. This paper presents an improved version of the Scout Flip-Flop, the Low-power version, a performance Sensor for tolerance and predictive detection of delay-faults in synchronous digital circuits, which now can operate at power-supply subthreshold voltage levels. The sensor is based on a master-slave Flip-Flop (FF), the Scout FF, with built-in sensor functionality to locally identify critical operations, denoted here as in the eminence of an error, a performance error. The novelty of this solution is on the new architecture for sensor functionality, which allows the operation at VDDs’ subthreshold voltage levels. This feature makes Scout FF a unique solution to control DVFS and avoid delay-fault errors, allowing optimizing circuit operation and performance. To accomplish this, two distinct guard-band windows are created: a tolerance window; and a detection window. Simulations using a SPICE tool allowed characterizing the new sensor and flip-flop to work at sub-threshold voltages, and results are presented for a 65 nm CMOS technology, which uses Predictive Technology Models (PTM). The results show that the improved Scout’s version is effective on tolerance and predictive error detection, working at subthreshold voltages.
Low-voltage bipolar-type DC microgrid is an emerging alternative for electric systems with high p... more Low-voltage bipolar-type DC microgrid is an emerging alternative for electric systems with high penetration of distributed generation (DG). The DG sources usually generate energy in DC form. This type of generation needs an interface to adapt the level of voltage from the source to the network. These interfaces usually consist of DC-DC converters. In this work, a new DC-DC converter is proposed for this application. This topology allows obtaining a DC bipolar output from a single DC input. The new converter consists of combining two basic converters, Zeta and Buck-Boost single inductor converter sharing the switch. It is possible because both converters have the same instantaneous duty cycle. For high power, various combined converters connected in parallel and operating in interleaved mode is proposed. This configuration gives high power with low ripple at the output and input currents. An analysis of the proposed configuration for different performance modes and load conditions is...
LATW 2011 - 12th IEEE Latin-American Test Workshop, 2011
In current nanometer technologies, aging effects (due for instance to Negative Bias Thermal Insta... more In current nanometer technologies, aging effects (due for instance to Negative Bias Thermal Instability) may appear after relatively short operating times, compared to the expected lifetime of circuits, even for relatively short-cycle consumer electronics. Therefore, there is an increasing need for on-chip aging monitoring. This paper presents a programmable aging sensor that can be embedded in FPGA-based designs, using standard resources available in those devices. The sensing principle is to monitor performance degradation over time. Depending on whether dynamic or static aging effects are dominant, the sensor can operate continuously or be only activated at some time intervals. Given the reduced amount of resources required by the sensor, it can be instantiated not only in the critical paths of a circuit, but also in those that may be identified to be more likely affected by aging affects. Experimental results are presented to demonstrate the performance of the proposed sensor.
RESUMO O presente texto tem o objectivo de introduzir os conceitos relacionados com a transmissão... more RESUMO O presente texto tem o objectivo de introduzir os conceitos relacionados com a transmissão de vídeo através da internet. Através da realização, implementação e estudo de uma plataforma de suporte ao serviço de vídeo a pedido, analisam-se os principais problemas inerentes ...
Multiple-output DC–DC converters are essential in a multitude of applications where different DC ... more Multiple-output DC–DC converters are essential in a multitude of applications where different DC output voltages are required. The interest and importance of this type of multiport configuration is also reflected in that many electronics manufacturers currently develop integrated solutions. Traditionally, the different output voltages required are obtained by means of a transformer with several windings, which are in addition to providing electrical isolation. However, the current trend in the development of multiple-output DC–DC converters follows general aspects, such as low losses, high-power density, and high efficiency, as well as the development of new architectures and control strategies. Certainly, simple structures with a reduced number of components and power switches will be one of the new trends, especially to reduce the size. In this sense, the incorporation of devices with a Wide Band Gap (WBG), particularly Gallium Nitride (GaN) and Silicon Carbide (SiC), will establi...
2021 XXXVI Conference on Design of Circuits and Integrated Systems (DCIS), 2021
As technology advances and becomes increasingly smaller in scale, it makes performance and reliab... more As technology advances and becomes increasingly smaller in scale, it makes performance and reliability a constant problem. Effects such as process variations (P), power-supply voltage variations (V), temperature variations (T) and aging (A) variations (PVTA - Process, Voltage, Temperature and Aging) are key parameters that affect circuit's performance and reliability. In today's SoC (System-on-Chip), the memory capacity is gaining importance, due to the need to store more and more data in the chips. The Complementary Metal Oxide Semiconductor (CMOS) memories are the most used in the integrated circuits, within the several types of memories. In this paper, a new performance sensor for SRAM memories is proposed. The purpose is to signalize when PVTA variations change performance above a certain threshold limit, jeopardizing memory operation and signal integrity. Sensor's sensibility to PVTA variations can be changed in run-time, which allows the sensor to be tuned during circuit's life time. Another important feature is that it can be applied locally in key locations, to monitor the online operation of the memory, or globally, by monitoring a dummy memory in pre-defined conditions.
Augmented reality (AR) nowadays is focused in two senses, sight and hearing. The work presented h... more Augmented reality (AR) nowadays is focused in two senses, sight and hearing. The work presented here is part of the Mobile Five Senses Augmented Reality system for Museums (M5SAR) project, which has the goal of developing an AR system to be a guide in cultural and historical events and museums, complementing or replacing traditional guides, directional signs or maps, while enhancing the user’s experience by adding multisensorial information to multiple museum objects. The existing solutions for this type of devices either lack portability or fail to implement all the human senses at the same time. This paper presents a new device capable of extending augmented reality experiences to all five human senses, through the use of a portable device that can reproduce stimulus of touch, taste and smell. The proposed apparatus is meant to be paired with a mobile application that controls which sensorial interface is activated and when, relaying that information to the portable device. The ap...
2015 16th Latin-American Test Symposium (LATS), 2015
The purpose of this paper is to present a Fault-Tolerance methodology for FPGA-based designs, foc... more The purpose of this paper is to present a Fault-Tolerance methodology for FPGA-based designs, focusing power reduction or performance enhancement during on-field operation. The methodology is based on a new performance sensor which predictively detects errors in critical paths, either allowing power-supply voltage (VDD) to be reduced, or clock frequency (fclk) to be raised, driving power reduction or performance increase. The HDL sensor's functionality is defined by the designer, according to the target circuit configuration in the FPGA structure. The adaptive scheme uses an Automatic Voltage and Frequency Controller (AVFC) to modify fclk and/or VDD, while still guaranteeing safe operation. The built-in sensors identify performance deviations in pre-identified critical paths during circuit operation and along product lifetime, caused by parametric variations and/or aging. The fclk increase is made possible by reducing the pessimistic safety-margins defined by standard simulation tools to account for variability. The sensors delay margins are programmable, so an adequate delay margin can guarantee safe operation. Conversely, the same performance can be achieved with lower VDD. Simulation and experimental results with Virtex 5 and Spartan 6 FPGAs show that significant performance improvements (typically, 30%) can be achieved with this methodology.
Product development economics and specs drive the need for on chip embedded test functionality. H... more Product development economics and specs drive the need for on chip embedded test functionality. However, optimal partitioning of test functionality between a tester and a SOC is a non-trivial task, which must be solved during the system analysis phase. Hence, at system level, a trade-off analysis must be performed, in order to evaluate the costs and benefits of different partitioning
ABSTRACT This paper presents a methodology to use global and local performance sensors, allowing ... more ABSTRACT This paper presents a methodology to use global and local performance sensors, allowing the circuits to be optimized for power and/or performance.
2016 Conference on Design of Circuits and Integrated Systems (DCIS), 2016
CMOS memories occupy a significant percentage of the Integrated Circuits footprint. With the deve... more CMOS memories occupy a significant percentage of the Integrated Circuits footprint. With the development of new manufacturing technologies to a smaller scale, performance and reliability challenges exist, namely caused by parametric variations such as Process variations (P), power supply Voltage (V) and Temperature (T), and Aging (A) or, in a general perspective, PVTA variations. The purpose of this paper is to present an aging and performance sensor, for CMOS memory cells, namely for SRAM cells, sensing and signaling performance degradation caused e.g. by PVTA variations. The detection strategy consists on the active monitoring on the bit lines the read and write operations performed by the memory cell. In the presence of PVTA degradations, read and write operations have slower transitions, which indicate performance degradation, thus increasing the probability of error occurrence. Hence, when transitions do not occur during the expected time frame, an error signal is flagged to th...
Proceedings of the 2007 IEEE Workshop on Design and Diagnostics of Electronic Circuits and Systems, DDECS, 2007
As IC technology scales down, power supply voltage and temperature variations play an increasing ... more As IC technology scales down, power supply voltage and temperature variations play an increasing role in signal integrity loss, which lead to performance degradation, reliability problems and functional errors. In this paper, we propose a new methodology to improve synchronous circuits' tolerance to power-supply voltage and temperature oscillations, without degrading its performance. The underlying principle of the proposed methodology is
The purpose of this work is to develop a non-intrusive low-cost system capable of detecting fault... more The purpose of this work is to develop a non-intrusive low-cost system capable of detecting faults and register working hours of Internal Combustion (IC) engines. The system should allow the monitoring of combustion engines usage, detect faults remotely, and is focused on IC engines for maritime applications. It consists of two parts, as explained in the following. The first part involves the development of the device, which should be capable of performing a continuous monitoring of an engine’s activity and register its working periods. This decision is made based on the vibration analysis. As a requirement, the developed device must be low-cost, portable and have a low energy consumption to provide at least two years of autonomy. The second part involves fault’s detection and, like the first part, it requires information from the engine’s vibrations. A low power accelerometer will be used to monitor the engine’s activity, and a piezoelectric polyvinylidene fluoride film is used to ...
Recently there has been an increase of interest in implementing a new set of home energy manageme... more Recently there has been an increase of interest in implementing a new set of home energy management devices that integrate Information Technologies, the Internet of Things and the ability tocommunicatebetween several appliances. Such energy management devices constitute an important milestone on the path to the Smart Grid, by being able to perform load-scheduling, taking into consideration different variables, such as the forecasted power generation from renewable sources, different tariffs' rates, electric circuit constraints, user restrictions and correspondent comfort levels. To achieve it, they are required to maintain machine-to-machine communications with home appliances, while performing human-computer interaction through simple and intuitive solutions. In order to improve user experience when interacting with such devices, several depth and movement sensors are currently available thatenable humans to interact with machines in innovative ways. In this paper, a 3D gesture recognition solution is explored, showingthatwhen combined with 2D and 3D representations of building, objectsand menus, allow humans to interact intuitively with energy management devices, in a way that cannot be achieved with other interface paradigms.
The first major step in training an object detection model to different classes from the availabl... more The first major step in training an object detection model to different classes from the available datasets is the gathering of meaningful and properly annotated data. This recurring task will determine the length of any project, and, more importantly, the quality of the resulting models. This obstacle is amplified when the data available for the new classes are scarce or incompatible, as in the case of fish detection in the open sea. This issue was tackled using a mixed and reversed approach: a network is initiated with a noisy dataset of the same species as our classes (fish), although in different scenarios and conditions (fish from Australian marine fauna), and we gathered the target footage (fish from Portuguese marine fauna; Atlantic Ocean) for the application without annotations. Using the temporal information of the detected objects and augmented techniques during later training, it was possible to generate highly accurate labels from our targeted footage. Furthermore, the d...
2020 IEEE 14th International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), 2020
This paper presents and describes switched-capacitor DC-DC combination converters with a single i... more This paper presents and describes switched-capacitor DC-DC combination converters with a single input and multiple outputs, with step-down and step-up voltage ratios. The combination converters provide two or three different DC outputs (depending on the combination), with different conversion ratios. The main advantage of the proposed converters is the low number of components used in the combination (two-output configurations require two link capacitors, and three-output configurations require three link capacitors) and two complementary phase clocks, which may reduce size and manufacturing costs for many applications. The DC-DC combination converters are designed to be fully integrated, and were implemented in a 65nm CMOS technology. The analysis of the proposed configurations for different performance modes and load conditions is presented, and simulation results show that these combination converter topologies are suitable for multiple-output switched-capacitor DC-DC converters with multiple conversion ratios.
As the number of Plug-In Electric Vehicles continues to rise, existing electrical grids need to a... more As the number of Plug-In Electric Vehicles continues to rise, existing electrical grids need to adapt to support the expected charging demand of such vehicles. Fortunately, a growing number of renewable energy sources are also being introduced in current electrical grids, reducing the dependency on fossil fuels. Leveraged by the self-consumption legislation in several countries, the introduction of renewable energy sources continue to happen well beyond the end of the feed-in tariff rates. However, due to their variable nature, renewable energy sources are frequently characterized as intermittent resources, which cause mismatches in the required equilibrium between production and demand. In this scenario, the role of end users is very important, since they are not only required to participate in energy generation - becoming the so-called prosumers – but also they should allow the adjustment of the consumption, according with the generation levels. Plug-In Electric Vehicles, due to t...
In this paper a comparative analysis of the tracking efficiency reported by two tracking systems ... more In this paper a comparative analysis of the tracking efficiency reported by two tracking systems of the maximum power point (MPPT) of a photovoltaic (PV) generator is carried out.
The work developed consists in an aging-aware dynamic voltage or frequency scaling methodology, t... more The work developed consists in an aging-aware dynamic voltage or frequency scaling methodology, to be used in long-term operation, using global and local performance sensors. Methodology allows circuits to be dynamically optimized, during their lifetime , according with one of two possible needs: (1) restrict power consumption, by reducing power-supply voltage to the minimum value that prevents errors from happening; or (2) optimize performance, by increasing operating frequency to the maximum limit that prevents errors' occurrence. The dynamic optimization is achieved by using a cooperative work of global and local sensors. Moreover, a new local sensor is presented, to obtain an enhanced solution with additional tolerance to delayfaults, allowing to achieve higher improvement in power or frequency optimization, or to achieve a higher safety and control margin. Spice simulations in a 65nm CMOS technology demonstrate the results for an example of a dynamic frequency scaling strategy.
The low power quest in CMOS integrated circuits is pushing power-supply voltages to enter the sub... more The low power quest in CMOS integrated circuits is pushing power-supply voltages to enter the subthreshold levels. The drastic power savings obtained in subthreshold voltage operation makes this an important technique to be used in battery-operated devices. However, working at subthreshold power-supply voltages, frequency operation has to be reduced, making Dynamic Voltage and Frequency Scaling (DVFS) methodologies hard to implement. In fact, existing solutions use wide safety margins and DVFS are typically implemented with static and pre-defined steps, both for the supply-voltage or the clock frequency. But changes in VDD and in clock frequency impose additional challenges, as delay faults may arise, especially in nanometer technologies. Moreover, when a PVTA (Process, power-supply Voltage, Temperature and Aging) variation occurs, circuit performance is affected and circuits are more prone to have delay-faults, especially when cumulative degradations pile up. This paper presents an improved version of the Scout Flip-Flop, the Low-power version, a performance Sensor for tolerance and predictive detection of delay-faults in synchronous digital circuits, which now can operate at power-supply subthreshold voltage levels. The sensor is based on a master-slave Flip-Flop (FF), the Scout FF, with built-in sensor functionality to locally identify critical operations, denoted here as in the eminence of an error, a performance error. The novelty of this solution is on the new architecture for sensor functionality, which allows the operation at VDDs’ subthreshold voltage levels. This feature makes Scout FF a unique solution to control DVFS and avoid delay-fault errors, allowing optimizing circuit operation and performance. To accomplish this, two distinct guard-band windows are created: a tolerance window; and a detection window. Simulations using a SPICE tool allowed characterizing the new sensor and flip-flop to work at sub-threshold voltages, and results are presented for a 65 nm CMOS technology, which uses Predictive Technology Models (PTM). The results show that the improved Scout’s version is effective on tolerance and predictive error detection, working at subthreshold voltages.
Low-voltage bipolar-type DC microgrid is an emerging alternative for electric systems with high p... more Low-voltage bipolar-type DC microgrid is an emerging alternative for electric systems with high penetration of distributed generation (DG). The DG sources usually generate energy in DC form. This type of generation needs an interface to adapt the level of voltage from the source to the network. These interfaces usually consist of DC-DC converters. In this work, a new DC-DC converter is proposed for this application. This topology allows obtaining a DC bipolar output from a single DC input. The new converter consists of combining two basic converters, Zeta and Buck-Boost single inductor converter sharing the switch. It is possible because both converters have the same instantaneous duty cycle. For high power, various combined converters connected in parallel and operating in interleaved mode is proposed. This configuration gives high power with low ripple at the output and input currents. An analysis of the proposed configuration for different performance modes and load conditions is...
LATW 2011 - 12th IEEE Latin-American Test Workshop, 2011
In current nanometer technologies, aging effects (due for instance to Negative Bias Thermal Insta... more In current nanometer technologies, aging effects (due for instance to Negative Bias Thermal Instability) may appear after relatively short operating times, compared to the expected lifetime of circuits, even for relatively short-cycle consumer electronics. Therefore, there is an increasing need for on-chip aging monitoring. This paper presents a programmable aging sensor that can be embedded in FPGA-based designs, using standard resources available in those devices. The sensing principle is to monitor performance degradation over time. Depending on whether dynamic or static aging effects are dominant, the sensor can operate continuously or be only activated at some time intervals. Given the reduced amount of resources required by the sensor, it can be instantiated not only in the critical paths of a circuit, but also in those that may be identified to be more likely affected by aging affects. Experimental results are presented to demonstrate the performance of the proposed sensor.
RESUMO O presente texto tem o objectivo de introduzir os conceitos relacionados com a transmissão... more RESUMO O presente texto tem o objectivo de introduzir os conceitos relacionados com a transmissão de vídeo através da internet. Através da realização, implementação e estudo de uma plataforma de suporte ao serviço de vídeo a pedido, analisam-se os principais problemas inerentes ...
Multiple-output DC–DC converters are essential in a multitude of applications where different DC ... more Multiple-output DC–DC converters are essential in a multitude of applications where different DC output voltages are required. The interest and importance of this type of multiport configuration is also reflected in that many electronics manufacturers currently develop integrated solutions. Traditionally, the different output voltages required are obtained by means of a transformer with several windings, which are in addition to providing electrical isolation. However, the current trend in the development of multiple-output DC–DC converters follows general aspects, such as low losses, high-power density, and high efficiency, as well as the development of new architectures and control strategies. Certainly, simple structures with a reduced number of components and power switches will be one of the new trends, especially to reduce the size. In this sense, the incorporation of devices with a Wide Band Gap (WBG), particularly Gallium Nitride (GaN) and Silicon Carbide (SiC), will establi...
2021 XXXVI Conference on Design of Circuits and Integrated Systems (DCIS), 2021
As technology advances and becomes increasingly smaller in scale, it makes performance and reliab... more As technology advances and becomes increasingly smaller in scale, it makes performance and reliability a constant problem. Effects such as process variations (P), power-supply voltage variations (V), temperature variations (T) and aging (A) variations (PVTA - Process, Voltage, Temperature and Aging) are key parameters that affect circuit's performance and reliability. In today's SoC (System-on-Chip), the memory capacity is gaining importance, due to the need to store more and more data in the chips. The Complementary Metal Oxide Semiconductor (CMOS) memories are the most used in the integrated circuits, within the several types of memories. In this paper, a new performance sensor for SRAM memories is proposed. The purpose is to signalize when PVTA variations change performance above a certain threshold limit, jeopardizing memory operation and signal integrity. Sensor's sensibility to PVTA variations can be changed in run-time, which allows the sensor to be tuned during circuit's life time. Another important feature is that it can be applied locally in key locations, to monitor the online operation of the memory, or globally, by monitoring a dummy memory in pre-defined conditions.
Augmented reality (AR) nowadays is focused in two senses, sight and hearing. The work presented h... more Augmented reality (AR) nowadays is focused in two senses, sight and hearing. The work presented here is part of the Mobile Five Senses Augmented Reality system for Museums (M5SAR) project, which has the goal of developing an AR system to be a guide in cultural and historical events and museums, complementing or replacing traditional guides, directional signs or maps, while enhancing the user’s experience by adding multisensorial information to multiple museum objects. The existing solutions for this type of devices either lack portability or fail to implement all the human senses at the same time. This paper presents a new device capable of extending augmented reality experiences to all five human senses, through the use of a portable device that can reproduce stimulus of touch, taste and smell. The proposed apparatus is meant to be paired with a mobile application that controls which sensorial interface is activated and when, relaying that information to the portable device. The ap...
2015 16th Latin-American Test Symposium (LATS), 2015
The purpose of this paper is to present a Fault-Tolerance methodology for FPGA-based designs, foc... more The purpose of this paper is to present a Fault-Tolerance methodology for FPGA-based designs, focusing power reduction or performance enhancement during on-field operation. The methodology is based on a new performance sensor which predictively detects errors in critical paths, either allowing power-supply voltage (VDD) to be reduced, or clock frequency (fclk) to be raised, driving power reduction or performance increase. The HDL sensor's functionality is defined by the designer, according to the target circuit configuration in the FPGA structure. The adaptive scheme uses an Automatic Voltage and Frequency Controller (AVFC) to modify fclk and/or VDD, while still guaranteeing safe operation. The built-in sensors identify performance deviations in pre-identified critical paths during circuit operation and along product lifetime, caused by parametric variations and/or aging. The fclk increase is made possible by reducing the pessimistic safety-margins defined by standard simulation tools to account for variability. The sensors delay margins are programmable, so an adequate delay margin can guarantee safe operation. Conversely, the same performance can be achieved with lower VDD. Simulation and experimental results with Virtex 5 and Spartan 6 FPGAs show that significant performance improvements (typically, 30%) can be achieved with this methodology.
Product development economics and specs drive the need for on chip embedded test functionality. H... more Product development economics and specs drive the need for on chip embedded test functionality. However, optimal partitioning of test functionality between a tester and a SOC is a non-trivial task, which must be solved during the system analysis phase. Hence, at system level, a trade-off analysis must be performed, in order to evaluate the costs and benefits of different partitioning
ABSTRACT This paper presents a methodology to use global and local performance sensors, allowing ... more ABSTRACT This paper presents a methodology to use global and local performance sensors, allowing the circuits to be optimized for power and/or performance.
2016 Conference on Design of Circuits and Integrated Systems (DCIS), 2016
CMOS memories occupy a significant percentage of the Integrated Circuits footprint. With the deve... more CMOS memories occupy a significant percentage of the Integrated Circuits footprint. With the development of new manufacturing technologies to a smaller scale, performance and reliability challenges exist, namely caused by parametric variations such as Process variations (P), power supply Voltage (V) and Temperature (T), and Aging (A) or, in a general perspective, PVTA variations. The purpose of this paper is to present an aging and performance sensor, for CMOS memory cells, namely for SRAM cells, sensing and signaling performance degradation caused e.g. by PVTA variations. The detection strategy consists on the active monitoring on the bit lines the read and write operations performed by the memory cell. In the presence of PVTA degradations, read and write operations have slower transitions, which indicate performance degradation, thus increasing the probability of error occurrence. Hence, when transitions do not occur during the expected time frame, an error signal is flagged to th...
Proceedings of the 2007 IEEE Workshop on Design and Diagnostics of Electronic Circuits and Systems, DDECS, 2007
As IC technology scales down, power supply voltage and temperature variations play an increasing ... more As IC technology scales down, power supply voltage and temperature variations play an increasing role in signal integrity loss, which lead to performance degradation, reliability problems and functional errors. In this paper, we propose a new methodology to improve synchronous circuits' tolerance to power-supply voltage and temperature oscillations, without degrading its performance. The underlying principle of the proposed methodology is
The purpose of this work is to develop a non-intrusive low-cost system capable of detecting fault... more The purpose of this work is to develop a non-intrusive low-cost system capable of detecting faults and register working hours of Internal Combustion (IC) engines. The system should allow the monitoring of combustion engines usage, detect faults remotely, and is focused on IC engines for maritime applications. It consists of two parts, as explained in the following. The first part involves the development of the device, which should be capable of performing a continuous monitoring of an engine’s activity and register its working periods. This decision is made based on the vibration analysis. As a requirement, the developed device must be low-cost, portable and have a low energy consumption to provide at least two years of autonomy. The second part involves fault’s detection and, like the first part, it requires information from the engine’s vibrations. A low power accelerometer will be used to monitor the engine’s activity, and a piezoelectric polyvinylidene fluoride film is used to ...
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Papers by Jorge Semião