11.5 Smart Energy and Automotive Systems

Time	Label	Presentation Title Authors
14:00	11.5.1	(Best Paper Award Candidate) ON REDUCING BUSY WAITING IN AUTOSAR VIA TASK-RELEASE-DELTA-BASED RUNNABLE REORDERING Speaker: Robert Höttger, Dortmund University of Applied Sciences and Arts, DE Authors: Robert Höttger¹, Olaf Spinczyk² and Burkhard Igel¹ ¹FH-Dortmund, DE; ²TU-Dortmund, DE Abstract The increasing amount of innovative software technologies in the automotive domain comes with challenges regarding inevitable distributed multi-core and many-core methodologies. Approaches for general purpose solutions have been studied over decades but do not completely meet the specific constraints (e.g. timing, safety, reliability, affinity, etc.) for AUTOSAR compliant applications. AUTOSAR utilizes a spinlock mechanism in combination with the priority ceiling protocol in order to provide mutually exclusive access to shared resources. The essential disadvantages of spinlocks are unpredictable task response times on the one hand and wasted computation time caused by busy waiting periods on the other hand. In this paper, we propose a concept of task-release-delta-based runnable reordering for the purpose of sequentializing parallel accesses to shared resources, resulting in reduced task response times, improved timing predictability, and increased parallel efficiency respectively. To achieve this, runnables that represent smallest executable program parts in AUTOSAR are reordered based on precedence constraints. Our experiments among industrial use cases show that task response times can be reduced by up to 18,2%. Download Paper (PDF; Only available from the DATE venue WiFi)
14:30	11.5.2	POWER NEUTRAL PERFORMANCE SCALING FOR ENERGY HARVESTING MP-SOCS Speaker: Benjamin Fletcher, University of Southampton, GB Authors: Benjamin Fletcher, Domenico Balsamo and Geoff Merrett, University of Southampton, GB Abstract Using energy 'harvested' from the environment to power autonomous embedded systems is an attractive ideal, alleviating the burden of periodic battery replacement. However, such energy sources are typically low-current and transient, with high temporal and spatial variability. To overcome this, large energy buffers such as supercapacitors or batteries are typically incorporated to achieve energy neutral operation, where the energy consumed over a certain period of time is equal to the energy harvested. Large energy buffers, however, pose environmental issues in addition to increasing the size and cost of systems. In this paper we propose a novel power neutral performance scaling approach for multiprocessor system-on-chips (MP-SoCs) powered by energy harvesting. Under power neutral operation, the system's performance is dynamically scaled through DVFS and DPM such that the instantaneous power consumption is approximately equal to the instantaneous harvested power. Power neutrality means that large energy buffers are no longer required, while performance scaling ensures that available power is effectively utilised. The approach is experimentally validated using the Samsung Exynos5422 big.LITTLE SoC directly coupled to a monocrystalline photovoltaic array, with only 47mF of intermediate energy storage. Results show that the proposed approach is successful in tracking harvested power, stabilising the supply voltage to within 5% of the target value for over 93% of the test duration, resulting in the execution of 69% more instructions compared to existing static approaches. Download Paper (PDF; Only available from the DATE venue WiFi)
15:00	11.5.3	EFFICIENT DECENTRALIZED ACTIVE BALANCING STRATEGY FOR SMART BATTERY CELLS Speaker: Nitin Shivaraman, Nanyang Technological University, SG Authors: Nitin Shivaraman¹, Arvind Easwaran¹ and Sebastian Steinhorst² ¹Nanyang Technological University, SG; ²Technical University of Munich, DE Abstract Among series-connected cells in large battery packs, such as those found in electric vehicles, a charge imbalance develops over time due to manufacturing and temperature variations. Therefore, active balancing strategies can be employed in Battery Management Systems (BMSs) to attain a charge balance among cells by transferring charge between them, maximizing the usable capacity of the battery pack. Recently, decentralized BMS architectures with smart battery cells have been developed, in which balancing strategies can operate by local cooperation between the cells without requiring global coordination. In this paper, we propose a decentralized active balancing strategy for smart cells where we identify boundary cells having special properties. These boundary cells enable to divide the global balancing problem into independent subproblems, where local decisions on charge transfers eventually converge to a globally balanced battery pack. The proposed strategy is implemented in a simulator framework and compared with two decentralized stateof- the-art strategies. Our results show significantly improved performance and scalability of the proposed strategy in terms of charge transfer losses and communication overhead between cells, while maintaining a comparable time to balance. Download Paper (PDF; Only available from the DATE venue WiFi)
15:15	11.5.4	WULORA: AN ENERGY EFFICIENT IOT END-NODE FOR ENERGY HARVESTING AND HETEROGENEOUS COMMUNICATION Speaker: Michele Magno, ETH Zurich, CH Authors: Michele Magno¹, Fayçal Ait Aoudia², Matthieu Gautier³, Olivier Berder⁴ and Luca Benini⁵ ¹ETH Zurich, CH; ²Irisa - University of Rennes, FR; ³University of Rennes 1, IRISA, INRIA, FR; ⁴Irisa -University of Rennes, FR; ⁵Università di Bologna, IT Abstract Intelligent connected objects, which build the IoT, are electronic devices usually supplied by batteries that significantly limit their life-time. These devices are expected to be deployed in very large numbers, and manual replacement of their batteries will severely restrict their large-scale or widearea deployments. Therefore energy efficiency is of the utmost importance in the design of these devices. The wireless communication between the distributed sensor devices and the host stations can consume significant energy, even more when data needs to reach several kilometers of distance. In this paper, we present an energy-efficient multi-sensing platform that exploits energy harvesting, long-range communication and ultra-low-power shortrange wake-up radio to achieve self sustainability in a kilometer range network. The proposed platform is designed with power efficiency in mind and exploits the always-on wake-up radio as both receiver and a power management unit to significantly reduce the quiescent current even continuously listening the wireless channel. Moreover the platform allows the building of an heterogeneous long-short range network architecture to reduce the latency and reduce the power consumption in listening phase at only 4.6µW. Experimental results and simulations demonstrate the benefits of the proposed platform and heterogeneous network. Download Paper (PDF; Only available from the DATE venue WiFi)
15:30	IP5-12, 84	FORMAL TIMING ANALYSIS OF NON-SCHEDULED TRAFFIC IN AUTOMOTIVE SCHEDULED TSN NETWORKS Speaker: Jürgen Teich, Friedrich-Alexander-Universität Erlangen-Nürnberg, DE Authors: Fedor Smirnov¹, Michael Glaß², Felix Reimann³ and Jürgen Teich¹ ¹Friedrich-Alexander-Universität Erlangen-Nürnberg, DE; ²Ulm University, DE; ³Audi Electronics Venture GmbH, DE Abstract To cope with requirements for low latency, the upcoming Ethernet standard Time-Sensitive Networking (TSN) provides enhancements for scheduled traffic, enabling mixedcriticality networks where critical messages are sent according to a system-wide schedule. While these networks provide a completely predictable behavior of the scheduled traffic by construction, timing analysis of the critical non-scheduled traffic with hard deadlines remains an unsolved issue. State-of-the-art analysis approaches consider the interference that unscheduled messages impose on each other, but there is currently no approach to determine the worst-case interference that can be imposed by scheduled traffic, the so-called schedule interference (SI), without relying on restrictions of the shape of the schedule. Considering all possible interference scenarios during each calculation of the SI is impractical, as it results in an explosion of the computation time. As a remedy, this paper proposes a) an approach to integrate the analysis of the worst-case SI into state-of-the-art timing analysis approaches and b) preprocessing techniques that reduce the computation time of the SI-calculation by several orders of magnitude without introducing any pessimism. Download Paper (PDF; Only available from the DATE venue WiFi)
15:31	IP5-13, 368	ULTRA LOW-POWER VISUAL ODOMETRY FOR NANO-SCALE UNMANNED AERIAL VEHICLES Speaker: Daniele Palossi, ETH Zurich, CH Authors: Daniele Palossi¹, Andrea Marongiu² and Luca Benini³ ¹ETH - Zurich, CH; ²Swiss Federal Institute of Technology in Zurich (ETHZ), CH; ³Università di Bologna, IT Abstract One of the fundamental functionalities for autonomous navigation of Unmanned Aerial Vehicles (UAVs) is the hovering capability. State-of-the-art techniques for implementing hovering on standard-size UAVs process camera stream to determine position and orientation (visual odometry). Similar techniques are considered unaffordable in the context of nano-scale UAVs (i.e. few centimeters of diameter), where the ultra-constrained power-envelopes of tiny rotor-crafts limit the on-board computational capabilities to those of low-power microcontrollers. In this work we study how the emerging ultra-low-power parallel computing paradigm could enable the execution of complex hovering algorithmic flows onto nano-scale UAVs. We provide insight on the software pipeline, the parallelization opportunities and the impact of several algorithmic enhancements. Results demonstrate that the proposed software flow and architecture can deliver unprecedented GOPS/W, achieving 117 frame-per-second within a power envelope of 10 mW. Download Paper (PDF; Only available from the DATE venue WiFi)
15:32	IP5-14, 598	LONG RANGE WIRELESS SENSING POWERED BY PLANT-MICROBIAL FUEL CELL Speaker: Maurizio Rossi, University of Trento, IT Authors: Maurizio Rossi, Pietro Tosato, Luca Gemma, Luca Torquati, Cristian Catania, Sergio Camalò and Davide Brunelli, University of Trento, IT Abstract Going low power and having a low or neutral impact on the environment is key for embedded systems, as pervasive and wearable consumer electronics is growing. In this paper, we present a self-sustaining, ultra-low power device, supplied by a Plant-Microbial Fuel Cell (PMFC) and capable of smart sensing and long-range communication. The use of a PMFC as a power source is challenging but has many advantages like the only requirement of watering the plant. The system uses aggressive power management thanks to FRAM technology exploited to retain microcontroller status and to shutdown electronics without losing context information. Experimental results show that the proposed system paves the way to energy neutral sensors powered by biosystems available almost anywhere on Earth. Download Paper (PDF; Only available from the DATE venue WiFi)
15:33	IP5-15, 717	ON THE COOPERATIVE AUTOMATIC LANE CHANGE: SPEED SYNCHRONIZATION AND AUTOMATIC "COURTESY" Speaker: Alexandre Lombard, UTBM, FR Authors: Alexandre Lombard¹, Florent Perronet¹, Abdeljalil Abbas-Turki² and Abdellah El-Moudni¹ ¹UTBM, FR; ²Université de Technologie de Belfort-Montbéliard, FR Abstract The recent ability of some vehicles to handle autonomously the lane change maneuvers, and the progressive equipment of roads and vehicles with ITS-G5 units motivate this paper to consider the case of road narrowing that requires a lane change because one lane is occupied by road works for maintenance, incidents and so on. This paper extends the approaches of cooperative speed synchronization at intersections. Because of the complexity of the overall system, it considers each automatic lane change as a mobile (unfixed) intersection in which vehicles synchronize their velocities. The wireless communication allows each vehicle to increase its field of view to negotiate its merging with the other equipped vehicles. Hence, the proposed approach introduces a kind of automatic "courtesy" between equipped vehicles. The paper defines the intersection point between each pair of vehicles and the suited protocol to safely reach the new lane. The protocol can be handled by the new work item (NWI) that has been created at ETSI to realize platooning and cooperative adaptive cruise control. Besides enhancing safety, the simulation results show that the main advantage of the approach is the energy saving by smoothing the traffic. Download Paper (PDF; Only available from the DATE venue WiFi)
15:30		End of session Coffee Break in Exhibition Area On all conference days (Tuesday to Thursday), coffee and tea will be served during the coffee breaks at the below-mentioned times in the exhibition area. Tuesday, March 28, 2017 Coffee Break 10:30 - 11:30 Coffee Break 16:00 - 17:00 Wednesday, March 29, 2017 Coffee Break 10:00 - 11:00 Coffee Break 16:00 - 17:00 Thursday, March 30, 2017 Coffee Break 10:00 - 11:00 Coffee Break 15:30 - 16:00

Time

Label

Presentation Title
Authors

14:00

11.5.1

(Best Paper Award Candidate)
ON REDUCING BUSY WAITING IN AUTOSAR VIA TASK-RELEASE-DELTA-BASED RUNNABLE REORDERING
Speaker:
Robert Höttger, Dortmund University of Applied Sciences and Arts, DE
Authors:
Robert Höttger¹, Olaf Spinczyk² and Burkhard Igel¹
¹FH-Dortmund, DE; ²TU-Dortmund, DE
Abstract
The increasing amount of innovative software technologies in the automotive domain comes with challenges regarding inevitable distributed multi-core and many-core methodologies. Approaches for general purpose solutions have been studied over decades but do not completely meet the specific constraints (e.g. timing, safety, reliability, affinity, etc.) for AUTOSAR compliant applications. AUTOSAR utilizes a spinlock mechanism in combination with the priority ceiling protocol in order to provide mutually exclusive access to shared resources. The essential disadvantages of spinlocks are unpredictable task response times on the one hand and wasted computation time caused by busy waiting periods on the other hand. In this paper, we propose a concept of task-release-delta-based runnable reordering for the purpose of sequentializing parallel accesses to shared resources, resulting in reduced task response times, improved timing predictability, and increased parallel efficiency respectively. To achieve this, runnables that represent smallest executable program parts in AUTOSAR are reordered based on precedence constraints. Our experiments among industrial use cases show that task response times can be reduced by up to 18,2%.
Download Paper (PDF; Only available from the DATE venue WiFi)

14:30

11.5.2

POWER NEUTRAL PERFORMANCE SCALING FOR ENERGY HARVESTING MP-SOCS
Speaker:
Benjamin Fletcher, University of Southampton, GB
Authors:
Benjamin Fletcher, Domenico Balsamo and Geoff Merrett, University of Southampton, GB
Abstract
Using energy 'harvested' from the environment to power autonomous embedded systems is an attractive ideal, alleviating the burden of periodic battery replacement. However, such energy sources are typically low-current and transient, with high temporal and spatial variability. To overcome this, large energy buffers such as supercapacitors or batteries are typically incorporated to achieve energy neutral operation, where the energy consumed over a certain period of time is equal to the energy harvested. Large energy buffers, however, pose environmental issues in addition to increasing the size and cost of systems. In this paper we propose a novel power neutral performance scaling approach for multiprocessor system-on-chips (MP-SoCs) powered by energy harvesting. Under power neutral operation, the system's performance is dynamically scaled through DVFS and DPM such that the instantaneous power consumption is approximately equal to the instantaneous harvested power. Power neutrality means that large energy buffers are no longer required, while performance scaling ensures that available power is effectively utilised. The approach is experimentally validated using the Samsung Exynos5422 big.LITTLE SoC directly coupled to a monocrystalline photovoltaic array, with only 47mF of intermediate energy storage. Results show that the proposed approach is successful in tracking harvested power, stabilising the supply voltage to within 5% of the target value for over 93% of the test duration, resulting in the execution of 69% more instructions compared to existing static approaches.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:00

11.5.3

EFFICIENT DECENTRALIZED ACTIVE BALANCING STRATEGY FOR SMART BATTERY CELLS
Speaker:
Nitin Shivaraman, Nanyang Technological University, SG
Authors:
Nitin Shivaraman¹, Arvind Easwaran¹ and Sebastian Steinhorst²
¹Nanyang Technological University, SG; ²Technical University of Munich, DE
Abstract
Among series-connected cells in large battery packs, such as those found in electric vehicles, a charge imbalance develops over time due to manufacturing and temperature variations. Therefore, active balancing strategies can be employed in Battery Management Systems (BMSs) to attain a charge balance among cells by transferring charge between them, maximizing the usable capacity of the battery pack. Recently, decentralized BMS architectures with smart battery cells have been developed, in which balancing strategies can operate by local cooperation between the cells without requiring global coordination. In this paper, we propose a decentralized active balancing strategy for smart cells where we identify boundary cells having special properties. These boundary cells enable to divide the global balancing problem into independent subproblems, where local decisions on charge transfers eventually converge to a globally balanced battery pack. The proposed strategy is implemented in a simulator framework and compared with two decentralized stateof- the-art strategies. Our results show significantly improved performance and scalability of the proposed strategy in terms of charge transfer losses and communication overhead between cells, while maintaining a comparable time to balance.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:15

11.5.4

WULORA: AN ENERGY EFFICIENT IOT END-NODE FOR ENERGY HARVESTING AND HETEROGENEOUS COMMUNICATION
Speaker:
Michele Magno, ETH Zurich, CH
Authors:
Michele Magno¹, Fayçal Ait Aoudia², Matthieu Gautier³, Olivier Berder⁴ and Luca Benini⁵
¹ETH Zurich, CH; ²Irisa - University of Rennes, FR; ³University of Rennes 1, IRISA, INRIA, FR; ⁴Irisa -University of Rennes, FR; ⁵Università di Bologna, IT
Abstract
Intelligent connected objects, which build the IoT, are electronic devices usually supplied by batteries that significantly limit their life-time. These devices are expected to be deployed in very large numbers, and manual replacement of their batteries will severely restrict their large-scale or widearea deployments. Therefore energy efficiency is of the utmost importance in the design of these devices. The wireless communication between the distributed sensor devices and the host stations can consume significant energy, even more when data needs to reach several kilometers of distance. In this paper, we present an energy-efficient multi-sensing platform that exploits energy harvesting, long-range communication and ultra-low-power shortrange wake-up radio to achieve self sustainability in a kilometer range network. The proposed platform is designed with power efficiency in mind and exploits the always-on wake-up radio as both receiver and a power management unit to significantly reduce the quiescent current even continuously listening the wireless channel. Moreover the platform allows the building of an heterogeneous long-short range network architecture to reduce the latency and reduce the power consumption in listening phase at only 4.6µW. Experimental results and simulations demonstrate the benefits of the proposed platform and heterogeneous network.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:30

IP5-12, 84

FORMAL TIMING ANALYSIS OF NON-SCHEDULED TRAFFIC IN AUTOMOTIVE SCHEDULED TSN NETWORKS
Speaker:
Jürgen Teich, Friedrich-Alexander-Universität Erlangen-Nürnberg, DE
Authors:
Fedor Smirnov¹, Michael Glaß², Felix Reimann³ and Jürgen Teich¹
¹Friedrich-Alexander-Universität Erlangen-Nürnberg, DE; ²Ulm University, DE; ³Audi Electronics Venture GmbH, DE
Abstract
To cope with requirements for low latency, the upcoming Ethernet standard Time-Sensitive Networking (TSN) provides enhancements for scheduled traffic, enabling mixedcriticality networks where critical messages are sent according to a system-wide schedule. While these networks provide a completely predictable behavior of the scheduled traffic by construction, timing analysis of the critical non-scheduled traffic with hard deadlines remains an unsolved issue. State-of-the-art analysis approaches consider the interference that unscheduled messages impose on each other, but there is currently no approach to determine the worst-case interference that can be imposed by scheduled traffic, the so-called schedule interference (SI), without relying on restrictions of the shape of the schedule. Considering all possible interference scenarios during each calculation of the SI is impractical, as it results in an explosion of the computation time. As a remedy, this paper proposes a) an approach to integrate the analysis of the worst-case SI into state-of-the-art timing analysis approaches and b) preprocessing techniques that reduce the computation time of the SI-calculation by several orders of magnitude without introducing any pessimism.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:31

IP5-13, 368

ULTRA LOW-POWER VISUAL ODOMETRY FOR NANO-SCALE UNMANNED AERIAL VEHICLES
Speaker:
Daniele Palossi, ETH Zurich, CH
Authors:
Daniele Palossi¹, Andrea Marongiu² and Luca Benini³
¹ETH - Zurich, CH; ²Swiss Federal Institute of Technology in Zurich (ETHZ), CH; ³Università di Bologna, IT
Abstract
One of the fundamental functionalities for autonomous navigation of Unmanned Aerial Vehicles (UAVs) is the hovering capability. State-of-the-art techniques for implementing hovering on standard-size UAVs process camera stream to determine position and orientation (visual odometry). Similar techniques are considered unaffordable in the context of nano-scale UAVs (i.e. few centimeters of diameter), where the ultra-constrained power-envelopes of tiny rotor-crafts limit the on-board computational capabilities to those of low-power microcontrollers. In this work we study how the emerging ultra-low-power parallel computing paradigm could enable the execution of complex hovering algorithmic flows onto nano-scale UAVs. We provide insight on the software pipeline, the parallelization opportunities and the impact of several algorithmic enhancements. Results demonstrate that the proposed software flow and architecture can deliver unprecedented GOPS/W, achieving 117 frame-per-second within a power envelope of 10 mW.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:32

IP5-14, 598

LONG RANGE WIRELESS SENSING POWERED BY PLANT-MICROBIAL FUEL CELL
Speaker:
Maurizio Rossi, University of Trento, IT
Authors:
Maurizio Rossi, Pietro Tosato, Luca Gemma, Luca Torquati, Cristian Catania, Sergio Camalò and Davide Brunelli, University of Trento, IT
Abstract
Going low power and having a low or neutral impact on the environment is key for embedded systems, as pervasive and wearable consumer electronics is growing. In this paper, we present a self-sustaining, ultra-low power device, supplied by a Plant-Microbial Fuel Cell (PMFC) and capable of smart sensing and long-range communication. The use of a PMFC as a power source is challenging but has many advantages like the only requirement of watering the plant. The system uses aggressive power management thanks to FRAM technology exploited to retain microcontroller status and to shutdown electronics without losing context information. Experimental results show that the proposed system paves the way to energy neutral sensors powered by biosystems available almost anywhere on Earth.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:33

IP5-15, 717

ON THE COOPERATIVE AUTOMATIC LANE CHANGE: SPEED SYNCHRONIZATION AND AUTOMATIC "COURTESY"
Speaker:
Alexandre Lombard, UTBM, FR
Authors:
Alexandre Lombard¹, Florent Perronet¹, Abdeljalil Abbas-Turki² and Abdellah El-Moudni¹
¹UTBM, FR; ²Université de Technologie de Belfort-Montbéliard, FR
Abstract
The recent ability of some vehicles to handle autonomously the lane change maneuvers, and the progressive equipment of roads and vehicles with ITS-G5 units motivate this paper to consider the case of road narrowing that requires a lane change because one lane is occupied by road works for maintenance, incidents and so on. This paper extends the approaches of cooperative speed synchronization at intersections. Because of the complexity of the overall system, it considers each automatic lane change as a mobile (unfixed) intersection in which vehicles synchronize their velocities. The wireless communication allows each vehicle to increase its field of view to negotiate its merging with the other equipped vehicles. Hence, the proposed approach introduces a kind of automatic "courtesy" between equipped vehicles. The paper defines the intersection point between each pair of vehicles and the suited protocol to safely reach the new lane. The protocol can be handled by the new work item (NWI) that has been created at ETSI to realize platooning and cooperative adaptive cruise control. Besides enhancing safety, the simulation results show that the main advantage of the approach is the energy saving by smoothing the traffic.
Download Paper (PDF; Only available from the DATE venue WiFi)

15:30

End of session
Coffee Break in Exhibition Area

On all conference days (Tuesday to Thursday), coffee and tea will be served during the coffee breaks at the below-mentioned times in the exhibition area.

Tuesday, March 28, 2017