DELICIOUS: Deadline-Aware Approximate Computing in Cache-Conscious Multicore

Enhancing result-accuracy in approximate computing (AC) based real-time systems, without violating power constraints of the underlying hardware, is a challenging problem. Execution of such AC real-time applications can be split into two parts: (i) the mandatory part , execution of which provides a result of acceptable quality, followed by (ii) the optional part , that can be executed partially or fully to refine the initially obtained result in order to increase the result-accuracy, without violating the time-constraint. This paper introduces DELICIOUS , a novel hybrid offline-online scheduling strategy for AC real-time dependent tasks. By employing an efficient heuristic algorithm , DELICIOUS first generates a schedule for a task-set with an objective to maximize the results-accuracy, while respecting system-wide constraints. During execution, DELICIOUS then introduces a prudential cache resizing that reduces temperature of the adjacent cores, by generating thermal buffers at the turned off cache ways. DELICIOUS further trades off this thermal benefits by enhancing the processing speed of the cores for a stipulated duration, called V/F Spiking , without violating the power budget of the core, to shorten the execution length of the tasks. This reduced runtime is exploited either to enhance result-accuracy by dynamically adjusting the optional part, or to reduce temperature by enabling sleep mode at the cores. While surpassing the prior art, DELICIOUS offers 80% result-accuracy with its scheduling strategy, which is further enhanced by 8.3% in online, while reducing runtime peak temperature by 5.8 ∘C on average, as shown by benchmark based evaluation on a 4-core based multicore

Proxy Circuits for Fault-Tolerant Primitive Interfacing in Reconfigurable Devices Targeting Extreme Environments

Continuous interface access to device-level primitives in reconfigurable devices in extreme environments is key to reliable operation. However, it is possible for a primitive's interface controller, which is static to be rendered non-operational by a permanent damage in the controller's circuitry. In order to mitigate this, this paper proposes the use of relocatable proxy circuits to provide remote interfacing capability to primitives from anywhere on a reconfigurable device. A demonstration with device register read controller shows that an improvement in fault-tolerance can be achieved

Travel Mode Recognition from GPS Data Based on LSTM

A large amount of GPS data contains valuable hidden information. With GPS trajectory data, a Long Short-Term Memory model (LSTM) is used to identify passengers' travel modes, i.e., walking, riding buses, or driving cars. Moreover, the Quantum Genetic Algorithm (QGA) is used to optimize the LSTM model parameters, and the optimized model is used to identify the travel mode. Compared with the state-of-the-art studies, the contributions are: 1. We designed a method of data processing. We process the GPS data by pixelating, get grayscale images, and import them into the LSTM model. Finally, we use the QGA to optimize four parameters of the model, including the number of neurons and the number of hidden layers, the learning rate, and the number of iterations. LSTM is used as the classification method where QGA is adopted to optimize the parameters of the model. 2. Experimental results show that the proposed approach has higher accuracy than BP Neural Network, Random Forest and Convolutional Neural Networks (CNN), and the QGA parameter optimization method can further improve the recognition accuracy

Profi-Load: An FPGA-Based Solution for Generating Network Load in Profinet Communication

Industrial automation has received a considerable attention in the last few years with the rise of Internet of Things (IoT). Specifically, industrial communication network technology such as Profinet has proved to be a major game changer for such automation. However, industrial automation devices often have to exhibit robustness to dynamically changing network conditions and thus, demand a rigorous testing environment to avoid any safety-critical failures. Hence, in this paper, we have proposed an FPGA-based novel framework called “Profi-Load” to generate Profinet traffic with specific intensities for a specified duration of time. The proposed Profi-Load intends to facilitate the performance testing of the industrial automated devices under various network conditions. By using the advantage of inherent hardware parallelism and re-configurable features of FPGA, Profi-Load is able to generate Profinet traffic efficiently. Moreover, it can be reconfigured on the fly as per the specific requirements. We have developed our proposed Profi-Load framework by employing the Xilinx-based “NetJury” device which belongs to Zynq-7000 FPGA family. A series of experiments have been conducted to evaluate the effectiveness of Profi-Load and it has been observed that Profi-Load is able to generate precise load at a constant rate for stringent timing requirements. Furthermore, a suitable Human Machine Interface (HMI) has also been developed for quick access to our framework. The HMI at the client side can directly communicate with the NetJury device and parameters such as, required load amount, number of packet(s) to be sent or desired time duration can be selected using the HMI

Real-Time Application Processing for FPGA-Based Resilient Embedded Systems in Harsh Environments

Real-time embedded systems nowadays get employed in harsh environments such as space, nuclear sites to carry out critical operations. Along with the traditional software based (CPU) execution, FPGAs are now also emerging as a bright prospect to accomplish such routines. However, these platforms are often get plagued by faults generated due to the high radiations in such environments. As a result, the real-time applications running on the platform could also get jeopardized. Thus, efficient execution of a set of hard real-time applications on reconfigurable systems with anomaly detection and recovery mechanism is inevitable. This work aims at tackling such problem with a “healing” approach for extreme environments. Initially, the applications are intelligently partitioned for hardware and software execution, then attempts have been made to schedule hardware applications with intermittent preemption point. Upon detecting any abnormality on such distinct points, our approach orchestrates a healing mechanism to remediate the scenario without hampering the pre-determined schedule. Experimental validation of our proposed method reveals its effectiveness

RewardProfiler: A Reward Based Design Space Profiler on DVFS Enabled MPSoCs

Resource mapping on a heterogeneous multi-processor system-on-chip (MPSoC) imposes enormous challenges such as identifying important design points for appropriate resource mapping for improved efficiency or performance, time consumption of exploring all the important design points for each profiled applications, etc. Moreover, incorporating a profiler into integrated development environments (IDEs) in order to achieve more detailed and accurate profiling information? on the application being targeted during runtime such that improved efficiency or performance while executing the application is achieved, the runtime resource management decision to achieve such improved "reward" has to be utilized in a certain way. In this paper, we propose a hybrid approach of resource mapping technique on DVFS enabled MPSoC, which is suitable for IDE integration due to the reduced design points in our methodology resulting in significant reduction in profiling time. We coined our approach as "RewardProfiler" (a Reward based design space Profiler), which is well capable of reducing the design space exploration without losing most of the important design points based on our heuristic approach. In our strategy, an application has to be mapped onto the available resources in such a way so that the "reward" obtained can be maximized. Our approach can also be utilized to maximize multiple "rewards" (Multivariate Reward Maximization) while executing an application. Implementation of our RewardProfiler on the Exynos 5422 MPSoC reveals the efficacy of our proposed approach under various experimental test cases and has a potential of saving 170× more time in profiling for our chosen MPSoC compared to the state-of-the-art methodologies

SENAS: Security driven ENergy Aware Scheduler for Real Time Approximate Computing Tasks on Multi-Processor Systems

Present day real time approximate computing applications like image and video processing involves execution of a set of tasks before a certain amount of time or deadline. In addition to this, present day systems are associated with strict energy budget that cannot be changed post deployment. The tasks comprises of a mandatory and optional part. Completion of all mandatory portions of all tasks before deadline is much more important than result accuracy in such real time approximate computing applications. Based on the energy budget, the optional portions can be executed that determines the quality of service (QoS) of the system. In ideal scenario, sufficient energy budget is present that ensures completion of both mandatory and optional portions in a system with a pre-determined number of processors. However, if fault or malware attack occurs on one or more processors, then the system will cease to work and results may be fatal. In this work, we consider such a scenario where the processors may be faulty and stop functioning in post deployment phases or some malware may cause unexpected delays in processing or may cause unexpected power draining at runtime that will prevent the system from meeting its deadline. We propose a Security driven ENergy Aware Scheduler (SENAS) that works as a self aware agent. Initially, based on the available energy budget, SENAS determines which task is to be executed in which processor of a system. At runtime, SENAS constantly monitors the working of the processors and on detecting any anomaly in any of the processors, it reschedules its tasks at runtime by reducing execution of the optional portions of the tasks and ensuring completion before deadline with high QoS