Effcient Handling of Lock Hand-off in DSM Multiprocessors with Buffering Coherence Controllers

Synchronization in parallel programs is a major performance bottleneck in multiprocessor systems. Shared data is protected by locks and a lot of time is spent on the competition arising at the lock hand-off. In order to be serialized, requests to the same cache line can either be bounced (NACKed) or buffered in the coherence controller. In this paper, we focus mainly on systems whose coherence controllers buffer requests. In a lock hand-off, a burst of requests to the same line arrive at the coherence controller. During lock hand-off only the requests from the winning processor contribute to progress of the computation, since the winning processor is the only one that will advance the work. This key observation leads us to propose a hardware mechanism we call request bypassing, which allows requests from the winning processor to bypass the requests buffered in the coherence controller keeping the lock line. We present an inexpensive implementation of request bypassing that reduces the time spent on all the execution phases of a critical section (acquiring the lock, accessing shared data, and releasing the lock) and which, as a consequence, speeds up the whole parallel computation. This mechanism requires neither compiler or programmer support nor ISA or coherence protocol changes. By simulating a 32-processor system, we show that using request bypassing does not degrade but rather improves performance in three applications with low synchronization rates, while in those having a large amount of synchronization activity (the remaining four), we see reductions in execution time and in lock stall time ranging from 14% to 39% and from 52% to 71%, respectively. We compare request bypassing with a previously proposed technique called read combining and with a system that bounces requests, observing a significantly lower execution time with the bypassing scheme. Finally, we analyze the sensitivity of our results to some key hardware and software parameters.     

A semi-Markov model for post-earthquake emergency response in a smart city

An earthquake significant on the Richter scale occurring in an area with a high population density requires an effective and equitable emergency response plan. Emergency resources are usually located in so-called responding centers. One of the first problems faced by disaster-response management personnel in the rapidly degrading post-earthquake conditions is to gage the hazard rate to which the disaster-affected area is subjected, estimate the time taken to bring the situation under control, also called restoration time, and select the appropriate responding center for relief-and-rescue activities. In this paper, we propose an elaborate semi-Markov model to capture the stochastic dynamics of the events that follow an earthquake, which will be used to quantify the hazard rate to which people are exposed and estimate the restoration time. The model will be further used, via dynamic programming, to determine the appropriate responding center. Our proposed model can be employed in conjunction with a variety of hazard scales and by collecting data on a few parameters related to emergency management. The model will be particularly useful in a smart city, where historic data on events following an earthquake would be systematically and accurately recorded.     

Performance-driven assignment and mapping for reliable networks-on-chips

Network-on-chip （NoC） communication architectures present promising solutions for scalable communication requests in large system-on-chip （SoC） designs. Intellectual property （IP） core assignment and mapping are two key steps in NoC design, significantly affecting the quality of NoC systems. Both are NP-hard problems, so it is necessary to apply intelligent algorithms. In this paper, we propose improved intelligent algorithms for NoC assignment and mapping to overcome the draw-backs of traditional intelligent algorithms. The aim of our proposed algorithms is to minimize power consumption, time, area, and load balance. This work involves multiple conflicting objectives, so we combine multiple objective optimization with intelligent algorithms. In addition, we design a fault-tolerant routing algorithm and take account of reliability using comprehensive performance indices. The proposed algorithms were implemented on embedded system synthesis benchmarks suite （E3S）. Experimental results show the improved algorithms achieve good performance in NoC designs, with high reliability.     

I/O performance of an RAID-10 style parallel file system

Without any additional cost, all the disks on the nodes of a cluster can be connected together through CEFT-PVFS, an RAID-10 style parallel file system, to provide a multi-GB/s parallel I/O performance.I/O response time is one of the most important measures of quality of service for a client. When multiple clients submit data-intensive jobs at the same time, the response time experienced by the user is an indicator of the power of the cluster. In this paper, a queuing model is used to analyze in detail the average response time when multiple clients access CEFT-PVFS. The results reveal that response time is with a function of several operational parameters. The results show that I/O response time decreases with the increases in I/O buffer hit rate for read requests, write buffer size for write requests and the number of server nodes in the parallel file system, while the higher the I/O requests arrival rate, the longer the I/O response time. On the other hand, the collective power of a large cluster supported by CEFT-PVFS is shown to be able to sustain a steady and stable I/O response time for a relatively large range of the request arrival rate.     

THE LAND USE INVESTIGATION IN TIBET PLATEAU USING REMOTE SENSING TECHNOLOGY

Tibet Plateau is Known as "the Roof of the World" with the area of 1,220,000km~2, which is about 1/8 land area of China. Because of the high elevation, cold climate and it caused difficulties in regional economic planning and land resources management. Since 1985, the land use investigation in Tibet has been carried out, in which the basic data and thematic maps must be obtained and completed at county and township levels, in order to meet the needs of local administrations. In the investigation, remote sensing technology was comprehensively adopted. At present, the investigation in county level had been completed and the compilation is going to be carried out. Due to paying a great attention to studying on a series of key technical problems, the systematic methods of using remote sensing technology in the plateau land use investigation were formed and successfully put into application.     

Labeled Network Stack: A High-Concurrency and Low-Tail Latency Cloud Server Framework for Massive IoT Devices

Internet of Things(IoT)applications have massive client connections to cloud servers,and the number of networked IoT devices is remarkably increasing.IoT services require both low-tail latency and high concurrency in datacenters.This study aims to determine whether an order of magnitude improvement is possible in tail latency and concurrency in mainstream systems by proposing a hardware-software codesigned labeled network stack(LNS)for future datacenters.The key innovation is a cross-layered payload labeling mechanism that distinguishes different requests by payload across the full network stack,including application,TCP/IP,and Ethernet layers.This type of design enables prioritized data packet processing and forwarding along the full datapath,such that latency-insensitive requests cannot significantly interfere with high-priority requests.We build a prototype datacenter server to evaluate the LNS design against a commercial X86 server and the mTCP research,using a cloud-supported IoT application scenario.Experimental results show that the LNS design can provide an order of magnitude improvement in tail latency and concurrency.A single datacenter server node can support over 2 million concurrent long-living connections for IoT devices as a 99-percentile tail latency of 50 ms is maintained.In addition,the hardware-software codesign approach remarkably reduces the labeling and prioritization overhead and constrains the interference of high-priority requests to low-priority requests.     

Dynamic call and connection admission control in automatically switched optical network for grid computing applications

In recent years,Grid computing applications are becoming more and more important to the scientific and business communities and are likely to open to the consumer market and widely develop in the near future,which is a great challenge brought by the potentially large number of Grid users(perhaps millions)and high frequency of their job requests.Automatically switched optical network(ASON),which is a promising high capacity intelligent transport network infrastructure,has been already deployed in the world and regarded as a promising solution to foster the expansion of Grid computing from local area networks to wide area networks.However,by theoretical analysis and simulative evaluation of Grid job blocking in the distributed call and connection setup process of ASON,this paper verifies that ASON and the conventional admission control mechanism confront a problem in supporting future large-scale Grid computing.In order to address this issue,a novel dynamic call and connection admission control(DCCAC)scheme is proposed to improve the network performance and guarantee quality of service(QoS)of Grid applications.This scheme is applicable with complete network information,no network information and partial network information.Numerical results show that the DCCAC scheme can improve the efficiency of the network to a great extent.Moreover,all the analysis and algorithms in this paper are based on ITU-T ASON recommendations,which make the DCCAC scheme more applicable in network engineering for future Grid computing.     

A new sliding function for discrete predictive sliding mode control of time delay systems

The control of time delay systems is still an open area for research. This paper proposes an enhanced model predictive discrete-time sliding mode control with a new sliding function for a linear system with state delay. Firstly, a new sliding function including a present value and a past value of the state, called dynamic surface, is designed by means of linear matrix inequalities （LMIs）. Then, using this dynamic function and the rolling optimization method in the predictive control strategy, a discrete predictive sliding mode controller is synthesized. This new strategy is proposed to eliminate the undesirable effect of the delay term in the closed loop system. Also, the designed control strategy is more robust, and has a chattering reduction property and a faster convergence of the system s state. Finally, a numerical example is given to illustrate the effectiveness of the proposed control.     

Semi-Markov adaptive critic heuristics with application to airline revenue management

The adaptive critic heuristic has been a popular algorithm in reinforcement learning(RL) and approximate dynamic programming(ADP) alike.It is one of the first RL and ADP algorithms.RL and ADP algorithms are particularly useful for solving Markov decision processes(MDPs) that suffer from the curses of dimensionality and modeling.Many real-world problems,however,tend to be semi-Markov decision processes(SMDPs) in which the time spent in each transition of the underlying Markov chains is itself a random variable.Unfortunately for the average reward case,unlike the discounted reward case,the MDP does not have an easy extension to the SMDP.Examples of SMDPs can be found in the area of supply chain management,maintenance management,and airline revenue management.In this paper,we propose an adaptive critic heuristic for the SMDP under the long-run average reward criterion.We present the convergence analysis of the algorithm which shows that under certain mild conditions,which can be ensured within a simulator,the algorithm converges to an optimal solution with probability 1.We test the algorithm extensively on a problem of airline revenue management in which the manager has to set prices for airline tickets over the booking horizon.The problem has a large scale,suffering from the curse of dimensionality,and hence it is difficult to solve it via classical methods of dynamic programming.Our numerical results are encouraging and show that the algorithm outperforms an existing heuristic used widely in the airline industry.     

基于便携式智能设备的管理系统设计

以智能化住宅小区物业管理为应用背景,介绍了一种基于便携式智能设备的管理系统的设计.该系统由智能终端设备和PC机两部分组成.智能终端设备实现数据采集和存储,并通过高速接口与PC机通信;PC机部分由VB6.0实现与智能设备的通信及数据的分析和处理.     

网络音频会议系统的开发

简要介绍了VOIP和数据压缩等相关技术,具体阐述了如何应用Visual C＋＋和Windows SDK实现几个人利用PC通过网络进行语音会议的应用程序.着重分析了会议召开过程中成员加入、离开、状态通知等管理问题和数据包的保序、时延、网络断连等传输问题.详细介绍了会议管理、网络传输、录音和放音的设计和实现.最终实现了多个PC之间通过internet进行实时语音通讯的应用程序.     

Digital Rights Management Scheme for Mobile

A digital rights management scheme for mobile is proposed according to the characteristics of mobile terminal in this paper. The proposed scheme can offer an effective, flexible and most importantly-security way for owner to deliver digital content such as music, gaines and publications over the mobile network. Furthermore, the scheme can be not only compatible with mobile terminals from light power to weight power, but also compatible with mobile terminals from cellular handsets to PDAs and game machines, and the system can also be applied to communications via broadband networks and personal computers.     

基于物联网的机房环境综合监控系统设计与实现

机房环境动力、视频监控和门禁系统相互独立,没有融合统一的监控平台,存在信息无法共享等问题.针对地点分散的多个信息机房监控系统的设计,采用嵌入式数据采集主机、网络摄像机、网络门禁主机构成信息传感层,以有线和无线网络作为信息传输层,最后以机房环境综合监控平台和各种管理终端构建核心业务层,建立基于物联网的分布式联网机房环境综合监控系统.该系统融合了机房环境动力监控、视频监控、门禁管理,实现了互通互联,数据交换和信息共享.在这种物联网中,管理人员可以随时随地与机房设备进行信息交互,监控和管理整个机房环境,实现了多机房集中监控、分布管理的模式,提升了机房智能化管理水平.     

Use of simulation in the analysis of shop floor operations

The use of computers in actual system applications is increasing with the availability of intelligent terminals on the shop floor. These terminals can be used by management as tools in the decision making process of planning shop floor operation. This paper discusses a pilot simulation study in the use of conventional Fortran-based simulation programs by shop floor management to:

1. 1. Participate in the evaluation of proposed FMS systems,

2. 2. Assess the impact of FMS acquisition on existing facilities,

3. 3. Assist in the identification of operational alternatives in “bottle neck” situations.

The pilot study employs a batch-oriented MRP system to provide daily updates of outstanding production center loadings on a monthly planning horizon. Two intelligent terminals are used to access a mini computer facility that executes the simulation models. The terminals have AT-compatible capabilities and are also used as data acquisition devices that support the numerically controlled operations within each work center.

The simulation models represent the 13 work centers of the firm and provide information about the average utilization of each work center, the number of parts in each queue and the average delay of parts in the queues. Future extensions of the models are planned to utilize the terminals' graphic animation capabilities to display the flow of production orders through the manufacturing facility.     

基于SOPC的公共区域智能照明监控系统

提出了一种适用于公共区域的新型绿色照叫控制技术解决方案。首先采用SOPCBuilder搭建智能照明控制终端,实现了对灯具的多模式控制。然后使用VB设计出远程监控用户界面,再配合数据库,采用以太网方式进行通信,实现了对监控终端的实时临控与信息管理。     

基于体域网的个人健康监护系统设计

体域网(BSN,body sensor networks)是以人为中心,由分布在人体表、贴身衣物上,或身体内部检测人体生命体征的多个传感器节点以及个人智能终端组成的无线通信网络.介绍了一种基于ZigBee和蓝牙无线通信协议的个人健康监护体域网系统,该系统通过3G智能手机终端控制穿戴在人体上的传感器节点,实时采集人体血氧、心音、心电和血压等生命体征参数,并以无线通信方式依次传送至智能终端显示,进一步实现与社区医院或中心医院的远程数据交互.系统终端应用程序运行在Android操作系统下,界面设计友好,适用于所有Android操作系统的3G智能手机用户.     

A simple network interacting programs' executive (SNIPE)

A small operating system SNIPE has been developed to enable minicomputers on the National Physical Laboratory's Data Communication Network to be used from terminals anywhere on this network. The system allows users to load and run programs over the network and provides network input and output facilities (e.g. for file transfers) with terminals and other computers. SNIPE has been kept small enough to be readily used for many network-based minicomputer, microprocessor and intelligent terminal applications.     

基于LoRa协议的智能防溜系统多信道数据通信

设计了一种基于LoRa协议的多信道智能防溜系统,实现了对智能铁鞋业务数据的实时、可靠上传。通过无线数据终端构建多级、多信道通信网络、业务数据及心跳数据以多种信道方式传输,数据有序上传,对不同来源、优先级数据打包发送,优先发送智能铁鞋溜逸数据帧。该数据传输方法实现了智能铁鞋数据的快速、可靠传输,有利于提高对站场智能铁鞋的管理效率,具有很高的理论意义和实用价值。     

Serial communication

Serial datalinks are most commonly used by computers to communicate with both local and remote terminals. In this article, the simple serial datalinks that are most often used are described.