Cluster Based Real Time Scheduling for Distributed System

Real time tasks scheduling on a distributed system is a complex problem. The existing real time tasks scheduling techniques are primarily based on partitioned and global scheduling. In partitioned based scheduling the tasks are assigned on a dedicated processor. The advantages of partitioned based approach is existing uni-processor scheduling techniques can be used; no migration overheads but task assignment is NP hard problem and optimal utilization of processing nodes is not possible. In global scheduling all tasks are maintained in a single tasks queue and allocated to multiple processing nodes. The advantage of global scheduling is optimal utilization of processing nodes but suffer from high migration and preemption overheads. This paper proposed cluster based real time tasks scheduling on a distributed system which is a hybrid scheduling approach where processing nodes group into cluster and scheduling using global scheduling. The simulation result shows that the proposed scheduling increases the tasks acceptance ratio, resource utilization as compared to partitioned and global scheduling and reduces migration as well as preemption overheads

Proceedings of the 5th International Workshop on Reconfigurable Communication-centric Systems on Chip 2010 - ReCoSoC\u2710 - May 17-19, 2010 Karlsruhe, Germany. (KIT Scientific Reports ; 7551)

ReCoSoC is intended to be a periodic annual meeting to expose and discuss gathered expertise as well as state of the art research around SoC related topics through plenary invited papers and posters. The workshop aims to provide a prospective view of tomorrow\u27s challenges in the multibillion transistor era, taking into account the emerging techniques and architectures exploring the synergy between flexible on-chip communication and system reconfigurability

ROS기반의 오픈소스 자율주행 플랫폼 시스템 최적화

학위논문(석사) -- 서울대학교대학원 : 공과대학 컴퓨터공학부, 2022. 8. 이창건.The open-source robot operating system(ROS) is being studied in complex system such as autonomous driving. Many studies have made efforts to port real-time to ROS for complex systems based on ROS. However, these methods are not user- friendly because they are difficult to use and require complicated procedures. This paper focused on the response time to improve ROS performance without modifying the ROS structure or adding other complicated procedures. We found that one of the characteristics of ROS causes response time delay. In this paper, we describe a method to improve response time with user convenience by using the characteristics of ROS. Finally, We show the performance of the method presented in this paper through several experiments.오픈소스 로봇운영체제(ROS)는 자율주행과 같은 복잡한 시스템에서 연구되고 있다. ROS를 기반으로 하는 복잡한 시스템을 위해 ROS에 실시간 이식을 위한 많은 연구가 이루어졌다. 그러나 이러한 방법은 사용하기 어렵고 복잡한 절차가 필요하기 때문에 사용자 친화적이지 않다. 이를 위해 본 논문에서는 ROS의 구조를 수정하거나 다른복잡한 절차를 추가하지 않고 ROS의 성능을 높이기 위하여 응답시간에 주목하였으며, ROS의 특성 중 하나가 응답시간 지연을 발생시키는 것을 발견하였다. 본 논문에서는 ROS의 특성을 이용하여 사용자의 편의성을 갖춘 응답시간 향상 방법을 설명한다. 마지막으로 본 논문에서 제시하는 방법의 성능을 몇 가지 실험을 통해 보인다1 Introduction 1 2 Backgound 3 2.1 ROS Structure 4 2.2 Node 4 3 Problem Description 7 3.1 Critical Chain 7 3.2 Observation 9 4 Proposed Approach 12 4.1 Assumption 12 4.2 Objective Function 13 4.3 Proposed Algorithm 15 5 Evaluation 16 5.1 Objective Function Evaluation 16 5.2 Response Time Evaluation 17 5.3 Autonomous Driving Evaluation Setup 18 5.4 Autonomous Driving Evaluation Result 19 6 Conclusion 21 References 22석

Optimizing Sensor Network Reprogramming via In-situ Reconfigurable Components

International audienceWireless reprogramming of sensor nodes is a critical requirement in long-lived Wireless Sensor Networks (WSNs) for several concerns, such as fixing bugs, upgrading the operating system and applications, and adapting applications behavior according to the physical environment. In such resource-poor platforms, the ability to efficiently delimit and reconfigure the necessary portion of sensor software--instead of updating the full binary image--is of vital importance. However, most of existing approaches in this field have not been widely adopted to date due to the extensive use of WSN resources or lack of generality. In this article, we therefore consider WSN programming models and run-time reconfiguration models as two interrelated factors and we present an integrated approach for addressing efficient reprogramming in WSNs. The middleware solution we propose, RemoWare, is characterized by mitigating the cost of post-deployment software updates on sensor nodes via the notion of in-situ reconfigurability and providing a component-based programming abstraction to facilitate the development of dynamic WSN applications. Our evaluation results show that RemoWare imposes a very low energy overhead in code distribution and component reconfiguration, and consumes approximately 6% of the total code memory on a TelosB sensor platform