Identification of redundancies and omissions among components of a web based architecture

A system, method and article of manufacture are provided for conveying redundancies and omissions among components of a network framework such as a web architecture framework. First, an area of an existing network framework is determined in which redundancies and omissions exist. Next, a pictorial representation of the existing network framework is presented along with a plurality of its components. The foregoing redundancies and the omissions are then highlighted by indicia coding the components of the existing network that reside in the area. As such, a diagnostic analysis of redundant efforts and gaps in a current implementation of the existing network framework is effectively conveyed.     

Adaptive air-fuel ratio control with MLP network

This paper presents an application of adaptive neural network model-based predictive control (MPC) to the air-fuel ratio of an engine simulation. A multi-layer perceptron (MLP) neural network is trained using two on-line training algorithms: a back propagation algorithm and a recursive least squares (RLS) algorithm. It is used to model parameter uncertainties in the nonlinear dynamics of internal combustion (IC) engines. Based on the adaptive model, an MPC strategy for controlling air-fuel ratio is realized, and its control performance compared with that of a traditional PI controller. A reduced Hessian method, a newly developed sequential quadratic programming (SQP) method for solving nonlinear programming (NLP) problems, is implemented to speed up nonlinear optimization in the MPC.     

基于跨层强化思想的传感网络多跳路由协议实验性研究

Lossy link is one of the unique characteristics in random-deployed sensor networks. We envision that robustness and reliability of routing cannot be ensured purely in network layer. Our idea is to enhance the performance of routing protocol by cross-layer interaction. We modified mint protocol, a routing protocol in TinyOS and proposed an enhanced version of mint called PA-mint. A transmission power control interface is added to network layer in PA-mint. When routing performance of the current network is not satisfied, PA-mint monotonically increases the transmission power via the interface we added. PA-mint is able to connect orphan nodes and robust to node mobility or key nodes failure. In the case that automatic request retransmission is employed, the number of retransmissions can be reduced by PA-mint. Results from experiments show that PA-mint increases the reliability and robustness of routing protocol by cross-layer interaction.     

AquaSee: Predict Load and Cooling System Faults of Supercomputers Using Chilled Water Data

An analysis of real-world operational data of Tianhe-1A(TH-1A)supercomputer system shows that chilled water data not only can reflect the status of a chiller system but also are related to supercomputer load.This study proposes AquaSee,a method that can predict the load and cooling system faults of supercomputers by using chilled water pressure and temperature data.This method is validated on the basis of real-world operational data of the TH-1A supercomputer system at the National Supercomputer Center in Tianjin.Datasets with various compositions are used to construct the prediction model,which is also established using different prediction sequence lengths.Experimental results show that the method that uses a combination of pressure and temperature data performs more effectively than that only consisting of either pressure or temperature data.The best inference sequence length is two points.Furthermore,an anomaly monitoring system is set up by using chilled water data to help engineers detect chiller system anomalies.     

Cross-layer Enhancement to Multi-hop Routing in Sensor Networks： an Empirical Study

Lossy link is one of the unique characteristics in random-deployed sensor networks. We envision that robustness and reliability of routing cannot be ensured purely in network layer. Our idea is to enhance the performance of routing protocol by cross-layer interaction. We modified mint protocol, a routing protocol in TinyOS and proposed an enhanced version of mint called PA-mint. A transmission power control interface is added to network layer in PA-mint. When routing performance of the current network is not satisfied, PA-mint monotonically increases the transmission power via the interface we added. PA-mint is able to connect orphan nodes and robust to node mobility or key nodes failure. In the case that automatic request retransmission is employed, the number of retransmissions can be reduced by PA-mint. Results from experiments show that PA-mint increases the reliability and robustness of routing protocol by cross-layer interaction.     

AHBP: An efficient broadcast protocol for mobile Ad hoc networks

Broadcast is an important operation in many netowkr protocols.It is utilized to discover routes to unknown nodes in mobile ad hoc networks(MANETs) and is the key factor in scaling on -demand routing protocols to large networks.This paper presents the Ad Hoc Broadcast Protocol(AHBP)and its performance is discussed.In the protocol,messages,are only rebroadcast by broadcast relay gateways that constitute a connected dominating set of the network.AHBP can efficiently reduce the redundant messages which make flookding-like protocols perform badly in large dense networks.Simulations are conducted to determine the performance characteristics of the protocol.The simulation results have shown excellent reduction of broadcast redundancy with AHBP.It also contributes to a reduced level of broadcast collision and congestion.     

Event-triggered H∞ consensus control for input-constrained multi-agent systems via reinforcement learning

This article presents an event-triggered H∞ consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H∞ consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network; meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.     

A practical interconnection network RP(k) and its routing algorithms

Based on Petersen graph, a new interconnection network, the RP(k) network, is devel-oped and the properties of the RP(k) network are investigated. The diameter of the RP(k) network is [ k/2] + 2 and its degree is 5. We prove that the diameter of the RP(k) network is much smaller than that of the 2-D Torus network when the number of nodes in interconnection networks is less than or equal to 300. In order to analyze the communication performance in a group of nodes, we propose the concepts of the optimal node groups and the diameter of the optimal node groups. We also show that the diameter of the optimal node groups in the RP(k) network is less than that in the 2-D Torus net-work. Especially when the number of nodes in an optimal node group is between 6 and 100, the diam-eter of the optimal node groups in the RP(k) network is half of that in the 2-D Torus network. Further-more based on the RP(k) network we design a set of routing algorithms which are point-to-point rout-ing, permutation routing, one-to-al     

Harmonic suppressed bandpass filter using composite right/left handed transmission line

A wideband composite right/left handed transmission line (CRLH TL) in conjunction with its corresponding equivalent circuit model is studied based on a cascaded complementary single split ring resonator (CCSSRR).The characterization is performed by theory analysis,circuit simulation,and full-wave electromagnetic (EM) simulation.The negative refractive index (NRI) and backward wave propagation performance of the CRLH TL are demonstrated.For application,a bandpass filter (BPF) with enhanced out-of-band selectivity and harmonic suppression operating at the wireless local area network (WLAN) band is designed,fabricated,and measured by combining the CRLH TL with a complementary electric inductive-capacitive resonator (CELC).Three CELC cells with wideband stopband performance in the conductor strip and ground plane,respectively,are utilized in terms of single negative permeability.The design concept has been verified by the measurement data.     

A non-blocking locking method and performance evaluation on network of workstations

A network of workstation(NOW) can act as a single and scalable powerful computer by building a paralle and distributed computing platform on top of it.WAKASHI is such a platform system that supports persitent object management and makes full use of resources of NOW for high perforance transaction processing,One of the main difficulties to overcome is the bottleneck caused by concurrency control mechanism.Therefore,a non-bloking locking method is designed,by adopting several novel techniques to make it outperform the other typical locking methods such as 2PL:1) an SDG (Semantic Dependency Graph)based non-blocking locking protocol for fast transaction scheduling;2) a nmassively virtual memory based backup-page undo algorithm for fast restart;and 3) a multi-processor and multi-thread based transaction manager for fast execution.The new mechanisms have been implemented in WAKASHI and the performance comparison experiments have been implemented in WAKASHI and the performance comparison experiments with 2PL and DWDL have been done.The results show that the new method can outperform 2PL and DWDL under certain conditons.This is meaningful for choosing effective concurrency control mechanisms for improving transaction-rpocessing performance in NOW environments.     

Gromacs在神威蓝光超级计算机上的部署及应用

Gromacs是一个大型的分子动力学模拟软件。国家超算济南中心拥有两套高性能计算系统,分别为基于Intel CPU构建的高性能计算集群(理论峰值超过100T),以及基于国产SW1600 CPU构建的MPP超级计算系统(理论峰值超过1P)。本文介绍了Gromacs软件包在两个高性能计算平台的移植、部署,并以生物大分子作为实例在两个平台上进行了分子动力学模拟测试。     

TH-1: China’s first petaflop supercomputer

In recent years, heterogeneous systems and cooperative computing have become popular research directions in the field of high performance computing. With fast scaling of the size of high performance computer systems, problems such as power consumption and reliability come to the forefront. The aim of high performance computing has thus shifted from merely seeking peak performance to comprehensively pursuing high efficiency, which takes into consideration many factors including performance, cost, power, reliability and so on. A heterogeneous computing system consisting of general-purpose CPU(s) and special-purpose accelerator(s) features high performance, lower power consumption and low cost, etc. Hence, it has already become the mainstream in the field of high performance computing. However, such systems still face many challenges and problems, for example, programmability and reliability. In this paper, we firstly analyze the main challenges facing heterogeneous computing systems. Then, we introduce the architecture of the first petaflop computing system in China, the Tianhe-1 (TH-1) heterogeneous system, including its hardware/software interface and interconnect network. During development of the TH-1 system, several challenges were encountered; research into the solutions of these challenges is subsequently presented.     

“天河一号”大规模科学与工程计算应用

安装在国家超级计算天津中心(以下简称天津超算中心)的"天河一号"超级计算机系统是目前世界上最快的超级计算机,已广泛应用于多个高性能计算领域,并取得了一系列具有国际影响力的应用成果。本文主要介绍了"天河一号"在石油勘探数据处理、生物信息与生物医药、环境科学、工程仿真、磁约束聚变领域的最新应用成果,其成果表明"天河一号"在上述领域具有良好的可扩展性和并行效率,对自主科技创新和产业技术提升给予了巨大支撑。     

“天河一号”在生命科学研究中的应用

本文首先对高性能计算和"天河一号"超级计算机进行了简要概述。随后详细描述了高性能计算在生命科学领域中的两大重要应用:一个是生物大分子的动力学模拟,介绍用户在"天河一号"取得的一些应用成果和进行的应用性能测试;另一个是生物信息学研究,重点介绍了华大基因在基于"天河一号"开展的GPU并行软件测试取得的良好结果。最后展望了高性能计算在生命科学领域中的发展趋势。     

NEMO模式系统基于“天河一号”的存储性能分析与优化

在“天河一号”超级计算机上测试NEMO模式系统,针对NEMO模式在进行大量进程并发存储时所导致的整体应用性能下降问题,提出了并发进程分组输出优化方法。通过将大量并发存储的进程进行合理分组并排队输出,以解决大量进程同时读写文件时对存储资源的竞争所导致的存储效率下降问题。测试表明,在使用分组输出优化方法后,NEMO模式GYRE012算例的存储性能最高可提升33%以上,总体时间性能最高可提升28%以上。     

基于计算缓存方法的分子动力学程序性能优化

分子动力学数值模拟程序在现代高性能计算机上的计算效率往往很低,只能发挥系统峰值性能的几个百分点。本文对并行分子动力学程序PMD3D在联想深腾6800超级计算机上进行性能优化。通过性能分析,我们发现粒子相互作用力计算中相互关联的浮点运算严重影响了处理器的指令级并行效率,为此我们应用计算缓存的方法,将大量不规则的浮点计算进行缓存,达到一定规模后再进行向量化计算。这样使得单机性能在优化后提升4倍多,达到处理器峰值性能5.2GFlops的32.3%。最后,在深腾6800的64个节点的256个CPU上进行了并行性能测试,达到峰值运算性能1.3万亿次的27%。     

提升大规模集群上并行计算软件系统可靠性和服务性的方法与实践

大规模集群上的并行计算软件需要具备处理部分节点、网络等失效的容错能力,也需要具有易于管理、维护、移植和可扩展的服务能力。针对星形计算模型,研究和开发了一套并行计算框架。利用调度节点内部的可变粒度分解器、相关队列等方法,实现了全系统容错,且具有较好的易用性、可移植性和可扩展性。系统目前可以实现300TFlops计算能力下连续运行超过150h,而且还具有进一步的可扩展能力。     

Interpolation oriented parallel communication to optimize coupling in earth system modeling

Complicated global climate problems trigger researchers from different scientific disciplines to link multiphysics simulations called models for integrated modeling of climate changes by using a software framework called earth system modeling (ESM). As its critical component, coupler is in charge of connections and interactions among models. With the advance of next-generation models, greater data transfer volume and higher coupling frequency are expected to put heavy performance burden on coupler. High efficient coupling techniques are required. In this paper, we propose the sub-domain mapping method to improve the parallel coupling consisted of data transfer and data transformation. By using one specific interpolation oriented communication routing, the communication operations that are originally decentralized in various steps can be combined together for execution. This can reduce the redundant communications and the entailed synchronization costs. The tests on the Tianhe-1A (TH-1A) supercomputer show that our method can achieve 1.1 to 4.9 fold performance improvements. We also present further optimization solution for the multi-interpolation cases. The test results show that our method can achieve up to 3.4 fold speedup over the original coupling execution of the current climate system.     

A formal approach to protocol performance testing

This paper proposes a formal approach to protocol performance testing based on the extended concurrent TTCN,To meet the needs of protocol performance testing,concurrent TTCN is extended,and the extended concurrent TTCN‘s operational semantics is defined in terms of Input-Output Labeled Transition System.An architecture design of protocol performance test system is described,and an example of test cases and its test result are given.     

Research on key technologies of edge cache in virtual data space across WAN

The authors of this paper have previously proposed the global virtual data space system (GVDS) to aggregate the scattered and autonomous storage resources in China’s national supercomputer grid (National Supercomputing Center in Guangzhou, National Supercomputing Center in Jinan, National Supercomputing Center in Changsha, Shanghai Supercomputing Center, and Computer Network Information Center in Chinese Academy of Sciences) into a storage system that spans the wide area network (WAN), which realizes the unified management of global storage resources in China. At present, the GVDS has been successfully deployed in the China National Grid environment. However, when accessing and sharing remote data in the WAN, the GVDS will cause redundant transmission of data and waste a lot of network bandwidth resources. In this paper, we propose an edge cache system as a supplementary system of the GVDS to improve the performance of upper-level applications accessing and sharing remote data. Specifically, we first designs the architecture of the edge cache system, and then study the key technologies of this architecture: the edge cache index mechanism based on double-layer hashing, the edge cache replacement strategy based on the GDSF algorithm, the request routing based on consistent hashing method, and the cluster member maintenance method based on the SWIM protocol. The experimental results show that the edge cache system has successfully implemented the relevant operation functions (read, write, deletion, modification, etc.) and is compatible with the POSIX interface in terms of function. Further, it can greatly reduce the amount of data transmission and increase the data access bandwidth when the accessed file is located at the edge cache system in terms of performance, i.e., its performance is close to the performance of the network file system in the local area network (LAN).