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M/S Controller Area Network(CAN) System Using Shared-Clock scheduler

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武汉理工大学学报 2006年第S1期28卷 284-288页

作者： LIU Jianxin1,TAN Ping2,LIU Yu1 (1.School of Mechanical Engineering & Automation,Xihua University,Chengdu 610039,China 2.School of Mathematical & Computer Science,Xihua University,ChengDu 610039,China) School of Mechanical Engineering & Automation Xihua UniversityChengdu 610039China School of Mathematical & Computer Science Xihua UniversityChengDu 610039China

The Controller Area Network (CAN) is a well established control network for automotive and automation control applications. Time-Triggered Controller Area Network (TTCAN) is a recent development which introduces a session layer,for message scheduling,to the existing CAN standard,which is a two layer standard comprising of a physical layer and a data link layer. TTCAN facilitates network communication in a time-triggered fashion,by introducing a Time Division Multiple Access style communication scheme. This allows deterministic network behavior,where maximum message latency times can be quantified and guaranteed. In order to solve the problem of determinate time latency and synchronization among several districted units in one auto panel CAN systems,this paper proposed a prototype design implementation for a shared-clock scheduler based on PIC18F458 MCU. This leads to improved CAN system performance and avoid the latency jitters and guarantee a deterministic communication pattern on the bus. The real runtime performance is satisfied.

关键词： time-triggered controller area network auto panel shared-clock scheduler embedded System

scheduler Algorithm for Multi-Class Switch with Priority Threshold

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International Journal of Communications, Network and System Sciences 2012年第6期5卷 313-320页

作者： Abdul Aziz Abdul Rahman Kamaruzzaman Seman Kamarudin Saadan Ahmad Kamsani Samingan Azreen Azman Faculty of Computer Science & IT Universiti Putra Malaysia (UPM) Selangor Malaysia Faculty of Science & Technology Universiti Sains Islam Malaysia (USIM) Negeri Sembilan Malaysia Next Generation Access Telekom Research & Development Selangor Malaysia

The requirement for guaranteed Quality of Service (QoS) have become very essential since there are numerous network base application is available such as video conferencing, data streaming, data transfer and many more. This has led to the multi-class switch architecture to cater for the needs for different QoS requirements. The introduction of threshold in multi-class switch to solve the starvation problems in loss sensitive class has increased the mean delay for delay sensitive class. In this research, a new scheduling architecture is introduced to improve mean delay in delay sensitive class when the threshold is active. The proposed architecture has been simulated under uniform and non-uniform traffic to show performance of the switch in terms of mean delay. The results show that the proposed architecture has achieved better performance as compared to Weighted Fair Queueing (WFQ) and Priority Queue (PQ).

关键词： scheduler Priority Thresholds Multi-Class Quality of Service (QOS)

Multiband scheduler for Future Communication Systems

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International Journal of Communications, Network and System Sciences 2008年第1期1卷 1-9页

作者： Klaus DOPPLER Carl WIJTING Tero HENTTONEN Kimmo VALKEALAHTI Klaus DOPPLER Carl WIJTING Tero HENTTONEN Kimmo VALKEALAHTI Radio Communications CTC Nokia Research Center Helsinki Finland

Operation in multiple frequency bands simultaneously is an important enabler for future wireless communication systems. This article presents a new concept for scheduling transmissions in a wireless radio system operating in multiple frequency bands: the Multiband scheduler (MBS). The MBS ensures that the operation in multiple bands is transparent to higher network layers. Special attention is paid to achieving low delay and latency when operating the system in the multiband mode. In particular, we propose additions to the ARQ procedures in order to achieve this. Deployment details and assessment results are presented for two multiband deployment scenarios. The first scenario is operation in a spectrum sharing context where multiple bands are used: one dedicated band for basic service and one shared extension band for extended services. In the second scenario we consider multiband operation in a relay environment, where the two bands have different propagation properties and relays provide extra coverage and capacity in the whole cell.

关键词： Multiband Operation Scheduling Multiband scheduler IMT-Advanced Relaying Dynamic Spectrum Use Flexible Spectrum Use Spectrum Sharing

Testing gridded NWS 1-day observed precipitation analysis in a daily irrigation scheduler

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Agricultural Sciences 2013年第12期4卷 621-627页

作者： Gretchen F. Sassenrath J. M. Schneider A. M. Schmidt J. Q. Corbitt J. M. Halloran R. Prabhu Biological Systems Engineering University of Nebraska Lincoln USA Department of Agricultural and Biological Engineering Mississippi State University Mississippi USA Southeast Agricultural Research Center Kansas State University Parsons USA USDA Agricultural Research Service Crop Production Systems Research Unit Stoneville USA USDA Agricultural Research Service Grazinglands Research Laboratory El Reno USA USDA Agricultural Research Service New England Plant Soil and Water Research Laboratory University of Maine Orono USA

One of the inputs required by daily decision support tools for scheduling irrigation is the amount of water supplied by rainfall. In-field measurements of daily precipitation are expensive or laborious, while measurements from gauges within a few kilometers are frequently not representative due to the high spatiotemporal variability of precipitation. Online radarbased precipitation analyses from NOAA’s National Weather Service (NWS) have obvious potential to provide the needed data, but are known to have varying degrees of accuracy with location and conditions. The NWS precipitation analysis is computed on a 4 km × 4 km grid, so differences should also be expected between the product and individual gauge measurements under each grid cell. In order to test the utility of the NWS precipitation analysis in a daily irrigation scheduler, daily data were gathered in July 2012 from 18 weather stations under 2 NWS precapitation analysis grid cells across instru-mented research and production fields in the Mississippi Delta. Differences between individual station measurements and the NWS precipitation analysis are examined, and root-zone daily soil water deficits computed using both station data and the NWS precipitation analysis. Sub-grid spatial variability between gauge locations, and differences in precipitation between gauges and the gridded NWS analysis, are found to be similar to those reported elsewhere. Differences between time series of soil water deficit computed using the two different precipitation data sources are noted, but prove to be of limited impact on the decision to irrigate or not to irrigate. It is also noted that profile-filling rainfalls limit the impact of accumulating error, resetting the modeled soil water to “full”. Given the Delta-local practice of irrigating to replace full evapotranspirational water used, use of the NWS daily precipitation analysis data as input for a daily irrigation scheduler is judged not only acceptable, but also preferabl

关键词： Irrigation Daily Precipitation scheduler Gridded Radar

基于NPV scheduler软件的国外某铅锌矿露天境界优化

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现代矿业 2014年第8期30卷 11-12,33页

作者：杨棋北京矿冶研究总院

基于地质块体模型,采用NPV scheduler软件对国外某铅锌矿露天境界进行优化,得到了该矿山的最优境界和采剥进度计划,为矿山露天开采和投资提供了技术方案和决策依据。

关键词： NPV scheduler 露天境界优化采剥进度计划

Job schedulers for Big data processing in Hadoop environment： testing real-life schedulers using benchmark programs

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Digital Communications and Networks 2017年第4期3卷 260-273页

作者： Mohd Usama Mengchen Liu Min Chen Embedded and Pervasive Computing(EPIC) Lab School of Computer Science and Technology Huazhong University of Science and Technology wuhon 430074 China

At present, big data is very popular, because it has proved to be much successful in many fields such as social media, E-commerce transactions, etc. Big data describes the tools and technologies needed to capture, manage, store, distribute, and analyze petabyte or larger-sized datasets having different structures with high speed. Big data can be structured, unstructured, or semi structured. Hadoop is an open source framework that is used to process large amounts of data in an inexpensive and efficient way, and job scheduling is a key factor for achieving high performance in big data processing. This paper gives an overview of big data and highlights the problems and challenges in big data. It then highlights Hadoop Distributed File System (HDFS), Hadoop MapReduce, and various parameters that affect the performance of job scheduling algorithms in big data such as Job Tracker, Task Tracker, Name Node, Data Node, etc. The primary purpose of this paper is to present a comparative study of job scheduling algorithms along with their experimental results in Hadoop environment. In addition, this paper describes the advantages, disadvantages, features, and drawbacks of various Hadoop job schedulers such as FIFO, Fair, capacity, Deadline Constraints, Delay, LATE, Resource Aware, etc, and provides a comparative study among these schedulers.

关键词： Big Data Hadoop MapReduce HDFS scheduler Classification Locality Benchmark

Pinpointing and scheduling access conflicts to improve internal resource utilization in solid-state drives

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Frontiers of Computer Science 2019年第1期13卷 35-50页

作者： Xuchao XIE Liquan XIAO Dengping WEI Qiong LI Zhenlong SONG Xiongzi GE College of Computer National University of Defense TechnologyChangsha 410073China Department of Computer Science University of MinnesotaMinneapolisMN 55455USA

Modern solid-state drives (SSDs)are integrating more internal resources to achieve higher *** accesses across internal resources can potentially enhance the performance of ***,exploiting parallelism inside SSDs is challenging owing to real-time access *** this paper,we propose a highly parallelizable I/O scheduler (PIOS)to improve internal resource utilization in SSDs from the perspective of I/O ***, we first pinpoint the conflicting flash requests with precision during the address translation in the Flash Translation Layer (FTL).Then,we introduce conflict eliminated requests (CERs)to reorganize the I/O requests in the device-level queue by dispatching conflicting flash requests to different *** to the significant performance discrepancy between flash read and write operations,PIOS employs differentiated scheduling schemes for read and write CER queues to always allocate internal resources to the conflicting CERs that are more *** small dominant size prioritized scheduling policy for the write queue significantly decreases the average write *** high parallelism density prioritized scheduling policy for the read queue better utilizes resources by exploiting internal parallelism *** evaluation results show that the paralle/izable I/O scheduler (PIOS)can accomplish better SSD performance than existing I/O schedulers implemented in both SSD devices and operating systems.

关键词： solid-state drive access conflict I/O scheduler internal resource utilization PIOS

Energy Guarantee Scheme for Real-time Systems with Energy Harvesting Constraints

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International Journal of Automation and computing 2019年第3期16卷 354-368页

作者： Hussein El Ghor Maryline Chetto Laboratory of Embedded and Networked Systems Faculty of TechnologyLebanese UniversityB.P.813 SaidaLebanon Laboratory of Numerical Sciences of Nantes University of Nantes2 Avenue of Professor Jean Rouxel4475 CarquefouFrance

The growth of environmental energy harvesting has been explosive in wireless computing systems especially when replacing or recharging batteries manually is *** work investigates the scheduling of periodic weekly hard real-time tasks under energy *** on this motivation,we proposed a real-time scheduling algorithm,namely energy guarantee dynamic voltage and frequency scaling(EG-DVFS),that utilizes the earliest deadline-harvesting(ED-H)scheduling algorithm combined with dynamic voltage and frequency *** one is qualified as real-time since tasks must satisfy their timing *** assume that the preemptable tasks receive dynamic priorities according to the earliest deadline first(EDF)***-DVFS adjusts the processor's behavior by characterizing the properties of the energy source module,capacity of the stored energy as well as the harvested energy in a future ***,tasks are executed at full processor speed if the amount of energy in the battery is enough to finish its ***,the processor slows down task execution to the lowest possible processor speed while still guaranteeing to meet all the timing ***-DVFS mainly depends on the on-line computation of the slack time and the slack energy with dynamic voltage and frequency selection in order to achieve an improved system *** results show that EG-DVFS can achieve capacity savings up of up to 33%when compared to ED-H.

关键词： Real-time systems energy harvesting embedded systems power management dynamic voltage and frequency selection(DVFS) ED-H scheduler

Analysis and Programming of Kernel for Embedded Systems

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Journal of Software Engineering and Applications 2014年第1期7卷 14-26页

作者： Kyumann Im Woonchul Ham Division of Electronics and Information Engineering of Chonbuk National University Duckjin-Dong Jeonju-city South Korea

In this study, we present a miniOS kernel implemented via analysis of the context switching, the scheduler, and the memory management of the original OS kernel for an embedded system based on ARM core. Since this is a large subject, we have limited our scope to them only that made up an embedded operating system. The implemented miniOS kernel is composed only by them, to the exclusion of all other functions of the original kernel. Our goal is to modify the OS kernel depending on the product function. The implementation method of the miniOS kernel can be applicable to any OS being mounted based on the ARM core. Modifying the kernel depending on the product function can improve the OS booting speed as well as save the system memory. The functions of the scheduler, the context switching, and the memory management are described with the source in each section. The miniOS kernel was implemented in the Assembly and C language and was verified through the build and the test. The results are shown in the Section 5.

关键词： Context Switching scheduler Kernel OS Timer Embedded System