Optimal clock period FPGA technology mapping for sequential circuits

Abstract � In this paper � we study the technology mapping problem for sequential circuits for LUT� based FPGAs. Existing approaches map the combi� national logic between �ip��ops �FFs � while assum� ing the positions of the FFs are �xed. We study in this paper a new approach to the problem � in which retiming is integrated into the technology mapping process. We present a polynomial time technology mapping algorithm that can produce a mapping so� lution with the minimum clock period while assuming FFs can be arbitrarily repositioned by retiming. The algorithm has been implemented. Experimental re� sults on benchmark circuits clearly demonstrate the advantage of our approach. For many benchmark circuits � our algorithm produced mapping solutions with clock periods not attainable by a mapping al� gorithm based on existing approaches � even when it employs an optimal delay mapping algorithm for combinational circuits.

Partial Scan with Preselected Scan Signals

Abstract { A partial scan approach proposed recently selects scan signals without considering the availability of the ip-ops (FFs). Such a n approach can greatly reduce the number of scan signals since maximum freedom is allowed in scan signal selection. To actually scan the selected signals, we, however, must make them FF-driving signals. In this paper, we study the problem of modifying and retiming a circuit to make a pre-selected set of scan signals FF-driving signals while preserving the set of cycles being broken. We present a new approach for solving this problem. Based on the new approach w e design an ecient algorithm. Unlike a previous algorithm which inherently has no control over the area overhead incurred during the modication, our algorithm explicitly minimizes the area overhead. The algorithm has been implemented and encouraging results were obtained

Mobility and Privacy-Aware Offloading of AR Applications for Healthcare Cyber-Physical Systems in Edge Computing

Cyber-physical systems (CPSs) can be regarded as a new generation of systems which have been widely used for healthcare system. The introduction of Augmented Reality (AR) can further enhance the effectiveness of healthcare CPSs. AR applications can provide a better user experience in the health treatment process for both patients and clinicians. However, AR applications are computation-intensive, putting a substantial computational burden on AR devices. Fortunately, offloading AR applications to edge nodes can enable AR to be suitable for real-time applications. Nevertheless, AR applications deal with the patient’s private information; placing it on edge raises serious privacy concerns. Besides, the network structure of AR applications has spatio-temporal uncertainty. To tackle these issues, we jointly investigate the computation offloading for AR applications in the healthcare CPSs in edge computing considering user privacy protection and mobility. We propose a novel multi-objective meta-heuristic method based on the R2 indicator-II, which preserves privacy, and minimizes the Motion-to-photon latency, energy consumption, and maintain load balancing. Eventually, it verifies the efficiency and superiority of our proposed approach based on a certain scale of the experiments

Impedance Modeling and Stability Analysis of DFIG-Based Wind Energy Conversion System Considering Frequency Coupling

Impedance-based stability analysis is an effective method for addressing a new type of SSO accidents that have occurred in recent years, especially those caused by the control interaction between a DFIG and the power grid. However, the existing impedance modeling of DFIGs is mostly focused on a single converter, such as the GSC or RSC, and the influence between the RSC and GSC, as well as the frequency coupling effect inside the converter are usually overlooked, reducing the accuracy of DFIG stability analysis. Hence, the entire impedance is proposed in this paper for the DFIG-based WECS, taking coupling factors into account (e.g., DC bus voltage dynamics, asymmetric current regulation in the dq frame, and PLL). Numerical calculations and HIL simulations on RT-Lab were used to validate the proposed model. The results indicate that the entire impedance model with frequency coupling is more accurate, and it is capable of accurately predicting the system’s possible resonance points

Probability of detecting nematode infestations for quarantine sampling with imperfect extraction efficacy

For quarantine sampling, it is of fundamental importance to determine the probability of finding an infestation when a specified number of units are inspected. In general, current sampling procedures assume 100% probability (perfect) of detecting a pest if it is present within a unit. Ideally, a nematode extraction method should remove all stages of all species with 100% efficiency regardless of season, temperature, or other environmental conditions; in practice however, no method approaches these criteria. In this study we determined the probability of detecting nematode infestations for quarantine sampling with imperfect extraction efficacy. Also, the required sample and the risk involved in detecting nematode infestations with imperfect extraction efficacy are presented. Moreover, we developed a computer program to calculate confidence levels for different scenarios with varying proportions of infestation and efficacy of detection. In addition, a case study, presenting the extraction efficacy of the modified Baermann's Funnel method on Aphelenchoides besseyi, is used to exemplify the use of our program to calculate the probability of detecting nematode infestations in quarantine sampling with imperfect extraction efficacy. The result has important implications for quarantine programs and highlights the need for a very large number of samples if perfect extraction efficacy is not achieved in such programs. We believe that the results of the study will be useful for the determination of realistic goals in the implementation of quarantine sampling

The Instruction Separation Framework against Man-At-The-End Attacks:Protect What is Mattered On-the-Fly

Man-At-The-End (MATE) attack is constantly discussed in the information security research field. Though many detection and mitigation methods have been proposed in software protection (SP) industry, it is still considered as an open challenge in many aspects. For example, existing tools and consultation services are always costly and opaque. This lack of transparency raises concerns regarding whether the companies are adequately grasping the risks. In response to this kind of industry challenge, in this work, we aim to propose a new perspective of method to resolve multiple variations at a time – named The Instruction Separation Framework (ISF). It consists of four important techniques: the program instrumentation, the user mode monitor, kernel mode hooks, and the execution module. The aim of our framework is to provide foundational runtime software integrity against primary MATE attacks, such as binary patching, code injection, and memory hooking. More specifically, we first survey several state-of-the-art approaches on defending MATE attacks, and then demonstrate how our framework can achieve the goal by securing critical functions and data of the program on-the-fly. Finally, we discuss the trade-off between protection completeness and the runtime overhead

Deep-Learning-Based Trunk Perception with Depth Estimation and DWA for Robust Navigation of Robotics in Orchards

Agricultural robotics is a complex, challenging, and exciting research topic nowadays. However, orchard environments present harsh conditions for robotics operability, such as terrain irregularities, illumination, and inaccuracies in GPS signals. To overcome these challenges, reliable landmarks must be extracted from the environment. This study addresses the challenge of accurate, low-cost, and efficient landmark identification in orchards to enable robot row-following. First, deep learning, integrated with depth information, is used for real-time trunk detection and location. The in-house dataset used to train the models includes a total of 2453 manually annotated trunks. The results show that the trunk detection achieves an overall mAP of 81.6%, an inference time of 60 ms, and a location accuracy error of 9 mm at 2.8 m. Secondly, the environmental features obtained in the first step are fed into the DWA. The DWA performs reactive obstacle avoidance while attempting to reach the row-end destination. The final solution considers the limitations of the robot’s kinematics and dynamics, enabling it to maintain the row path and avoid obstacles. Simulations and field tests demonstrated that even with a certain initial deviation, the robot could automatically adjust its position and drive through the rows in the real orchard

Significant reduction in creep life of P91 steam pipe elbow caused by an aberrant microstructure after short-term service

Abstract P91 steel is an important steam pipe for ultra-supercritical power plants due to its excellent creep strength, which generally has a design life of 100,000 h. Here, we found a significant aberrant decrease in the creep rupture life of a main steam pipe elbow after only 20,000 h of service. The microstructure in the aberrant piece exhibited a decomposition of martensitic lath into blocky ferrite due to recrystallization and accumulation of M23C6 as well as formation of the Laves phase along the prior austenitic grain boundaries, resulting in the decrease of hardness that no long meet ASME standard requirement. The creep testing of the P91 piece at 550–600 °C and 85–140 MPa shows that the influence of temperature on the cavity formation and cracking is greater than that of the applied stress. The rupture life is nearly two orders of magnitude shorter than the normal P91, attributing to the creep damage of the subgrain growth, M23C6 and Laves phase coarsening (aggregation approaching 3.4 μm). The residual life of the aberrant piece was evaluated to be 53,353 h based on the Larson–Miller parameter, which is much shorter than the design life, suggesting the safety operation of the elbow area should be paid more attention during the afterward service periods. P91 steel, main steam pipe elbow, aberrant microstructure, service degradation, creep life predictio