Designing hybrid graph model and algorithmic analysis of workflow decomposition in mobile distributed systems

Ali, Ihtisham,Bagchi, Susmit North-Holland 2018 Future generations computer systems Vol.86 No.-

<P><B>Abstract</B></P> <P>The execution of data intensive workflow is challenging in the domain of mobile distributed systems due to the involvement of heterogeneous computing devices and dynamic network topology. Moreover, data intensive workflow execution requires frequent access to database servers for dataflow and control flow operations resulting in massive data transfer. The workflow decomposition and distribution are required to minimize data transfer and to reduce execution delay in mobile distributed systems. This paper proposes a hybrid graph model of workflow in mobile distributed systems relying on dynamic network topology and distributed database in order to facilitate workflow decomposition. The algebraic and numerical analysis of the hybrid graph model is represented providing inherent properties. Furthermore, we have presented an extensive analytical study of existing workflow decomposition approaches and have provided detailed analysis to determine the suitability of these approaches in mobile distributed systems. We have also proposed a novel framework and implementation directions for workflow decomposition based on multiple parameters for mobile distributed systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid graph model and algorithmic analysis of workflow decomposition in mobile distributed systems. </LI> <LI> Algebraic and numerical analysis of hybrid graph model and workflow decomposition in mobile distributed systems. </LI> <LI> Modeling workflow as hybrid graph and algorithmic analysis of workflow in mobile distributed systems. </LI> </UL> </P>

분산 시스템의 기능 및 비기능 검증을 위한 테스트 프레임워크 개발

윤상필 ( Sangpil Yun ),서용진 ( Yongjin Seo ),민법기 ( Bup-ki Min ),김현수 ( Hyeon Soo Kim ) 한국인터넷정보학회 2014 인터넷정보학회논문지 Vol.15 No.5

분산 시스템은 물리적으로 분산된 컴퓨터들이 네트워크에 의해 유기적으로 연결된 것을 의미한다. 유무선 인터넷의 보편적인 사용으로 인해 사용자는 언제 어디서나 분산 서비스의 이용이 가능하게 되었다. 분산 서비스의 폭발적인 증가는 서비스의 기능적 측면에서의 검증뿐만 아니라 서비스 품질과 관련된 비기능적 요소의 검증도 강하게 요구하고 있다. 분산 서비스를 검증하기 위해서는 분산 시스템에 맞는 테스트 환경을 구축해야 한다. 하지만 분산 시스템은 물리적으로 분산된 노드로 구성되기 때문에 테스트 환경을 구축함에 있어서 단일 시스템의 테스트 환경보다 많은 노력이 요구된다. 이 논문에서 우리는 분산 시스템의 기능 및 비기능 요소의 검증을 위한 테스트 프레임워크를 제안한다. 제안하는 테스트 프레임워크는 메시지 시퀀스 차트(Message Sequence Chart)를 기반으로 테스트 케이스를 자동 생성하며, 물리적으로 분산된 노드를 흉내 낼 수 있는 가상의 분산 노드로 구성된 테스트 드라이버를 포함 한다. 테스트 수행 결과는 다양한 그래프와 GUI를 통해서 쉽게 확인할 수 있다. 이 논문에서 제안하는 테스트 프레임워크를 통해 분산 시스템 테스트에 드는 노력을 감소할 수 있고 시스템의 신뢰성을 향상 시킬 수 있을 것이다. Distributed systems are collection of physically distributed computers linked by a network. General use of wired/wireless Internet enables users to make use of distributed service anytime and anywhere. The explosive growth of distributed services strongly requires functional verification of services as well as verification of non-functional elements such as service quality. In order to verify distributed services it is necessary to build a test environment for distributed systems. Because, however, distributed systems are composed of physically distributed nodes, efforts to construct a test environment are required more than those in a test environment for a monolithic system. In this paper we propose a test framework to verify functional and non-functional features of distributed systems. The suggested framework automatically generates test cases through the message sequence charts, and includes a test driver composed of the virtual nodes which can simulate the physically distributed nodes. The test result can be checked easily through the various graphs and the graphical user interface (GUI). The test framework can reduce testing efforts for a distributed system and can enhance the reliability of the system.

DEVS형식론을 적응한 HLA기반의 분산 실시간 시뮬레이션 시스템 개발

김호정,이재현,조길석,Kim, Ho-Jeong,Lee, Jae-Hyun,Cho, Kil-Seok 한국군사과학기술학회 2006 한국군사과학기술학회지 Vol.9 No.3

Weapon systems composed of several subsystems execute various engagement missions in distributed combat environments in cooperation with a large number of subordinate/adjacent weapon systems as well as higher echelons through tactical data links. Such distributed weapon systems require distributed real-time simulation test beds to integrate and test their operational software, analyze their performance and effects of cooperated engagement, and validate their requirement specifications. These demands present significant challenges in terms of real-time constraints, time synchronization, complexity and development cost of an engagement simulation test bed, thus necessitate the use of high-performance distributed real-time simulation architectures, and modeling and simulation techniques. In this paper, in order to meet these demands, we presented a distributed real-time simulation system based on High Level Architecture(HLA) and Discrete Event System Specification(DEVS). We validated its performance by using it as a test bed for developing the Engagement Control System(ECS) of a surface-to-air missile system. The proposed technique can be employed to design a prototype or model of engagement-level distributed real-time simulation systems.

A Study On Distributed Systems Management For OSI Environment

Park,Seung-Seob 釜山工業大學校 1994 論文集 Vol.36 No.-

情報 通信 네트워크의 大規模와 複雜性의 확대와 더불어 네트워크의 관리의 유연성, 고신뢰성등을 향상시키기 위해서 분산시스템 관리가 중요한 과제로 등장한다. 기존의 OSI 관리모델은 다음과 같은 여러가지 문제점이 있다. 1)分散 管理 環境에 적합한 시스템 構造設計 2)분산 관리 시스템을 支援하기 위한 통신 프로토콜 開發 3)管理 情報의 分類 등이다. 본 論文은 우에 서술한 첫번째 問題點을 해결하기 위해서, 效率的인 네트워크 관리를 위해서는 인텔리젼트 기능을 가진, 분산 네트워크 관리 시스템의 기본 구조를 提案하고, 그 중에서 중요한 要素인 시스템 관리 응용 프로세스의 具體的인 설계를 나타낸다. 두번째 문제점을 해결하기 위해서 분산 관리 시스템을 효율적으로 관리하기 위해서 비접속형 CMIP를 提案하고, 그 효율성을 제시한다. 이 프로토콜은 동적정보를 취급하기 위해서 관리하는 시스템사이의 交涉에 유용하다. 세번째 문제점을 극복하기위해서 관리 시스템의 階層的 構造에 있어서 접속기준을 나타내고, 종래의 집중식 시스템 관리와 제안된 분산 시스템 관리를 비교하며, 그리고 관리 시스템들 사이의 협조적인 교섭할 동한 제안된 프로토콜의 효율성에 의해 評價한다. As the size and complexty of network increase, Distributed Systems Management (DSM) will be singificant issue within information network in order to increase the high reliability and to improve the flexibility of network management. The OSI management model has several problems. The key problems are that it does not fully address the problem of how to define system architecture suitable for distributed management environment, how to develop communication protocol in support of DSM, and how to classify the management informations. In this paper, to solve first problem described above, we introduce the basic structure of distributed network management system(DNMS) with intelligent facilities for efficient network management, and also especially give the concrete design of system management application process the connectionless CMIP to accomplish for effectively managing the distributed management system, to handle the dynamic informations. To work out third problem, we introduce the connection criteria in the hierarchy of management systems, compare the conventional centralized systems management with the proposed distributed systems management, and finally evaluate the efficiency of a suggested protocol during cooperative negotiation among the manging systems.

Evaluation Algorithms for Multiple Function of Dispersed Electrical Energy Storage Systems

Joon-ho Son,Sung-Sik Choi,Dae-Seok Rho 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

With the increase of electrical consumption and the unbalance of power demand and supply, power reserve rate is getting smaller and also the reliability of the power supply is getting deteriorated. Under this circumstance, the electrical energy storage (EES) System is considered as one of essential countermeasure for demand side management. This paper proposes efficient evaluation algorithms of multiple functions for EES systems, especially the secondary battery energy storage systems, in the case where they are interconnected with the power distribution systems. It is important to perform the economic evaluation for the new energy storage systems in a quantitative manner, because they are very costly right now. In this paper, the multiple functions of EES systems such as load levelling, effective utilization of power distribution systems and uninterruptible power supply are classified, and then the quantitative evaluation methods for their functions are proposed. From the case studies, it is verified that EES systems installed at distribution systems in a dispersed manner have multiple functions involved with direct and indirect benefits and also they can be expected to introduce to distribution systems with respects to economical point of view.

Software architecture and algorithm for reliable RPC for geo-distributed mobile computing systems

Khan, Asmat Ullah,Bagchi, Susmit North-Holland 2018 Future generations computer systems Vol.86 No.-

<P><B>Abstract</B></P> <P>Remote Procedure Call (RPC) is a computing as well as communication model for distributed processes to execute client routines on remote servers in the distributed systems. Due to the evolution of geo-distributed mobile cloud computing systems, mobile devices are exposed to frequent disconnection due to limited battery lifetime, processing capacity and network bandwidth while roaming globally. The existing standard RPC and mobile RPC frameworks are not completely suitable for applications in geo-distributed mobile cloud computing. This paper proposes a novel software architecture and associated algorithms for realizing reliable RPC under global mobility of clients. The stateful server chaining and multiple authentication primitives are employed in the proposed design to achieve security as well as location transparency. The software architecture is implemented on heterogeneous testbed and evaluated with promising results. The heterogeneity of mobile cloud platform is considered in the design by employing specific XDR format enhancing portability. A detailed comparative analysis of the proposed design is included in the paper.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GMCC-RPC: Reliable mobile RPC for geo-distributed systems. </LI> <LI> Software architecture for mobile and reliable RPC for geo-distributed systems. </LI> <LI> Mobile and Reliable RPC using server chains in geo-distributed systems. </LI> </UL> </P>

Coq에서의 실시간 분산 시스템 검증을 위한 네트워크 및 운영체제 행동의 정형 모델 정의

김윤승,허충길 한국정보과학회 2020 정보과학회논문지 Vol.47 No.11

Improving the safety and reliability of distributed systems using formal verification methods is an urgent problem. As many of these distributed systems are safety-critical, such as medical or avionics systems, failures of these systems may cause catastrophic results. However, applying formal verification to distributed systems requires not only execution semantics in software, but also behavioral models of the environments, including the operating systems and network involved. We designed a formal abstract model of network and operating system behaviors with the Coq proof assistant. This model consists of local-site execution semantics that model a single computer, the composition of these local-site semantics along with a message exchange model constitutes the global system semantics. We applied and tested this model to verify its applicability when used in a simple server-client system. We expect this model to be used in the verification of practical systems. 정형 검증을 적용하여 분산 시스템의 안전성을 높이는 것은 중요한 과제이다. 분산 시스템 중 항공, 의료기기와 같은 안전 우선 시스템은 안전성의 위협이 큰 사고와 직결될 수 있다. 하지만 분산 시스템을 정형 검증하기 위해서는 소프트웨어의 실행 의미뿐만 아니라, 소프트웨어를 실행시키는 운영체제와 메시지를 전달하는 네트워크의 환경 등에 대한 기술이 필요하다. 우리는 Coq 증명 보조 도구 안에서 네트워크와 운영체제의 추상적인 행동에 대한 모델을 정의하였다. 이 모델은 단계적으로 네트워크 각 지역의 실행 규칙을 제시하고, 이로부터 전체 시스템의 행동을 구성한다. 우리는 이 모델이 실제로 분산 시스템 검증에 유용하게 사용될 수 있음을 보이기 위해 간단한 서버-클라이언트 시스템 검증을 수행하였으며, 이후 실용적인 소프트웨어 검증에 적용되기를 기대하고 있다.

분산 생산 시스템을 위한 에이전트 기반의 협업 시뮬레이션 체계

차영필,정무영 한국경영과학회 2003 한국경영과학회 학술대회논문집 Vol.- No.1

Maintaining agility and responsiveness in designing and manufacturing activities we the key issues for manufacturing companies to cope with global competition. Distributed design and control systems we regarded as an efficient solution for agility and responsiveness. However, distributed nature of a manufacturing system complicates production activities such as design, simulation, scheduling, and execution control. Especially, existing simulation systems have limited external integration capabilities, which make it difficult to implement complex control mechanisms for the distributed manufacturing systems. Moreover, integration and coupling of heterogeneous components and models are commonly required for the simulation of complex distributed systems. In this paper, a collaborative and adaptive simulation architecture is proposed as an open framework for simulation and analysis of the distributed manufacturing enterprises. By incorporating agents with their distributed characteristics of autonomy, intelligence, and goal-driven behavior, the proposed agent-based simulation architecture can be easily adapted to support the agile and distributed manufacturing systems. The architecture supports the coordination and cooperation relations, and provides a communication middleware among the participants in simulation.

Achieving Distributed Consensus in Networked Flexible-joint Manipulator Systems via Energy-shaping Scheme

Bin Zheng,Jin Zhou,Jinchen Ji,Zhonghua Miao 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

This paper deals with the distributed consensus problem for networked flexible-joint manipulator systems which are formulated by underactuated Euler-Lagrange (EL) dynamics. Based on the energy-shaping scheme of passivity-based control (PBC) with interconnection and damping assignment, a novel decentralized controller is proposed to solve the leaderless and the leader-follower consensus problems. The main feature of the present work is the systematical integration of the energy of the systems composed of underactuated and actuated components and the energy of the controller as a total energy. Then the total energy is formulated as a suitable Lyapunov function to solve distributed consensus problems for the networked underactuated EL systems. The proposed consensus scheme without the need of velocity measurement possesses a relatively simple structure and good robustness. It is shown that interconnection pattern and damping assignment of the PBC are two key factors to affect the cooperative behavior of networked flexible-joint manipulator systems, which will be used to regulate or improve the cooperative performance of networked flexible-joint manipulator systems in practice. Finally, two numerical examples of networked six flexible-joint manipulator systems are presented to validate the correctness of the proposed algorithms.

Analysis of the System Impact of Distributed Generation using EMTP

Yeo, Sang-Min,Kim, Il-Dong,Kim, Chul-Hwan,Aggarwal, Raj The Korean Institute of Electrical Engineers 2004 KIEE International Transactions on Power Engineeri Vol.a4 No.4

With the advent of distributed generation, power systems in general are impacted in regards to stability and power quality. Distributed generation has positive impacts on system restoration following a fault, higher reliability, and mitigation of effect due to voltage sag. However, distributed generation also has negative impacts on the decrease of reliability such as changes of protective device setting and mal-operation. Because bulk power systems consist of various sources and loads, it is complicated to analyze power systems that have distributed generation. The types of distributed generation usually are classified as the rotating machinery system and the inverter-based system. In this paper, distributed generation is designed as a synchronous generator, and the distribution system with its distributed generation model is simulated using EMTP. In addition, this paper shows the simulation results according to the types of distributed generation