BP-NUCA: Cache Pressure-Aware Migration for High-Performance Caching in CMPs

As the momentum behind Chip Multi-Processors (CMPs) continues to grow, Last Level Cache (LLC) management becomes a crucial issue to CMPs because off-chip accesses often involve a big latency. Private cache design is distinguished by smaller local access latency, good performance isolation and easy scalability, thus is becoming an attractive design alternative for LLC of CMPs. This paper proposes Balanced Private Non-Uniform Cache Architecture (BP-NUCA), a new LLC architecture that starts from private cache design for smaller local access latency and good performance isolation, then introduces a low cost mechanism to dynamically migrate private blocks among peer private caches of LLC to improve the overall space utilization. BP-NUCA achieves this by measuring the cache access pressure level that each cache set experiences at runtime and then using the information to guide block migration among different private caches of LLC. A heavily accessed set, namely a set with high access pressure level, is allowed to migrate its evicted blocks to peer private caches, replacing blocks of sets which are with the same index and have low access pressure level. By migrating blocks from heavily accessed cache sets to less accessed cache sets, BP-NUCA effectively balances space utilization of LLC among different cores. Experimental results using a full system CMP simulator show that BP-NUCA improves the overall throughput by as much as 20.3 %, 12.4 %, 14.5 % and 18.0 % (on average 7.7 %, 4.4 %, 4.0 % and 6.1 %) over private cache, shared cache, shared cache management scheme UCP and private cache organization CC respectively on a 4-core CMP for SPEC CPU2006 benchmarks

The feasibility and safety of sharp recanalization for superior vena cava occlusion in hemodialysis patients: A retrospective cohort study

Introduction: Hemodialysis catheter‐related superior vena cava (SVC) occlusions can cause considerable morbidity for patients and be challenging to treat if refractory to conventional guide wire transversal. This pilot study assessed the feasibility and safety of sharp recanalization of SVC occlusion in hemodialysis patients.Methods: This study retrospectively enrolled hemodialysis patients treated in West China Hospital diagnosed with SVC occlusion who failed traditional guide wire transversal from January 2014 to November 2017. In brief, a guide wire from the femoral approach was advanced to the lower end of the obstructive lesion to act as a target, while the stiff end of hydrophilic wire was advanced though a jugular approach. Under fluoroscopic guidance in biplane imaging, the occlusive SVC lesion was penetrated with the stiff wire that was snared and pulled through. Graded dilation of the SVC and subsequent tunneled‐cuffed catheter implantation were performed. Demographic information and clinical outcomes were recorded and evaluated.Findings: Sixteen patients with a mean age of 62 ± 13 years (13 females and 3 males) who received SVC sharp recanalization were included in this study. The sharp recanalization procedure was successfully performed in 14 patients (87.5%). Two patients were complicated with SVC laceration and hemopericardium but remained asymptomatic and required no surgical repair. One patient suffered ventricular fibrillation during procedure. Despite the return of spontaneous circulation, the patient unfortunately died of gastrointestinal tract bleeding after 3 days in ICU. Follow‐up suggested the 6‐month catheter patency to be 92.85% and 12‐month catheter patency to be 58.33%. No long‐term procedure‐related complications were recorded.Discussion: Sharp recanalization might be a feasible strategy in managing SVC occlusion in hemodialysis patients. The potential life‐threatening complications (cardiac arrhythmia and SVC laceration) necessitate strict eligibility screening, skillful operation, and avoidance of over‐dilation of SVC.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153765/1/hdi12804.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153765/2/hdi12804_am.pd

A Camera Stabilized Platform Based on the Feedforward Strap-Down Control with Approximate Dead-Zone Model and a Compensator with LESO

A feedforward strap-down control with a compensator base on the linear extended state observer (LESO) is proposed for a miniaturized camera stabilized platform, which reduces the influence of the dead zone in speed regulation and uncertainties in parameters to reduce the level of angular bias to the field of vision (FOV) in a low-cost stabilized platform. Firstly, the feedforward control is inspired by an approximate linear model proposed for the dead zone to improve the response velocity of the system when tracking the varying reference. Then, the compensator, combining the LESO and proportional differential (PD) law, is designed to eliminate the disturbances including the model bias in the dead zone, inaccuracy in the plant model, and external disturbance. Moreover, the observation performance of the LESO is improved by a preprocessor based on a tracking differentiator (TD) to deal with the time delay and nonlinearities in sampling the state variables. Meanwhile, the complex and uncertain control plant is also simplified by an approximate model combining a disturbance compensator for practical application. Finally, the feasibility of the proposed controller is verified and analyzed by the simulation, and its effectiveness is simultaneously validated by the 2-DOF camera stabilized platform

An LADRC Controller to Improve the Robustness of the Visual Tracking and Inertial Stabilized System in Luminance Variation Conditions

Disturbance from luminance variation in the identification of visual sensors causes instability in the control system of target tracking, which leads to field of vision (FOV) motion and even the target missing. To solve this problem, a linear active disturbance reject controller (LADRC) is adopted to the visual tracking and inertial stable platform (VTISP) for the first time to improve the system’s robustness. As a result, the random disturbance from identification can be smoothed by the tracking differentiator (TD).An improved linear extended state observer (LESO) modified by the TD is provided to obtain the high-order state variables for feedback. That makes the system avoid noise in a differential process from the MEMS gyroscope and enhances the response time and stability in tracking control. Finally, simulation and experimental studies are conducted, and the feasibility of the LADRC is verified. Moreover, compared with the other controller in the VTISP for remote sensing, the superiority of the LADRC in system response time and stability is proved by the experiments

A Camera Stabilized Platform Based on the Feedforward Strap-Down Control with Approximate Dead-Zone Model and a Compensator with LESO

A feedforward strap-down control with a compensator base on the linear extended state observer (LESO) is proposed for a miniaturized camera stabilized platform, which reduces the influence of the dead zone in speed regulation and uncertainties in parameters to reduce the level of angular bias to the field of vision (FOV) in a low-cost stabilized platform. Firstly, the feedforward control is inspired by an approximate linear model proposed for the dead zone to improve the response velocity of the system when tracking the varying reference. Then, the compensator, combining the LESO and proportional differential (PD) law, is designed to eliminate the disturbances including the model bias in the dead zone, inaccuracy in the plant model, and external disturbance. Moreover, the observation performance of the LESO is improved by a preprocessor based on a tracking differentiator (TD) to deal with the time delay and nonlinearities in sampling the state variables. Meanwhile, the complex and uncertain control plant is also simplified by an approximate model combining a disturbance compensator for practical application. Finally, the feasibility of the proposed controller is verified and analyzed by the simulation, and its effectiveness is simultaneously validated by the 2-DOF camera stabilized platform

An LADRC Controller to Improve the Robustness of the Visual Tracking and Inertial Stabilized System in Luminance Variation Conditions

Disturbance from luminance variation in the identification of visual sensors causes instability in the control system of target tracking, which leads to field of vision (FOV) motion and even the target missing. To solve this problem, a linear active disturbance reject controller (LADRC) is adopted to the visual tracking and inertial stable platform (VTISP) for the first time to improve the system’s robustness. As a result, the random disturbance from identification can be smoothed by the tracking differentiator (TD).An improved linear extended state observer (LESO) modified by the TD is provided to obtain the high-order state variables for feedback. That makes the system avoid noise in a differential process from the MEMS gyroscope and enhances the response time and stability in tracking control. Finally, simulation and experimental studies are conducted, and the feasibility of the LADRC is verified. Moreover, compared with the other controller in the VTISP for remote sensing, the superiority of the LADRC in system response time and stability is proved by the experiments

Harmonic Source Localization Approach Based on Fast Kernel Entropy Optimization ICA and Minimum Conditional Entropy

Based on the fast kernel entropy optimization independent component analysis and the minimum conditional entropy, this paper proposes a harmonic source localization method which aims at accurately estimating harmonic currents and identifying harmonic sources. The injected harmonic currents are estimated by the fast kernel entropy optimization independent component analysis (FKEO-ICA) in the absence of prior knowledge of harmonic impedances. Then, the minimum conditional entropy is applied to locate the harmonic sources based on the estimated harmonic currents. The proposed harmonic source localization method is validated on the IEEE 34-bus system. By applying the correlation coefficient and three error evaluation indicators, comparison has been made among the performances of the FKEO-ICA and three other ICA algorithms. The results show that the FKEO-ICA algorithm could achieve a significantly better accuracy of harmonic current estimation, while the minimum conditional entropy could determine the locations of harmonic sources precisely

An anti-windup method based on the modified linear extended state observer for actuators in the miniaturized inertial stabilized platform

This paper presents an anti-windup linear active disturbance rejection controller (LADRC) for a miniaturized inertial stabilized platform (MISP). To address the actuator saturation in acceleration during extreme external disturbance in the MISP, a modified linear extended state observer (MLESO) is proposed with a transition state compensator. Moreover, the proposed method is simple to implement in engineering, and the detailed process has been discussed. Simulation experiments are designed to verify the feasibility of the approach. Compared with the typical LESO during saturation, it effectively reduces the impact of accelerated saturation, which leads to high-frequency oscillations in the control process, and improves the stability of the line of sight (LOS)