• Title/Summary/Keyword: distributed programming

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A Database Schema Integration Method Using XML Schema (XML Schema를 이용한 이질의 데이터베이스 스키마 통합)

  • 박우창
    • Journal of Internet Computing and Services
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    • v.3 no.2
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    • pp.39-56
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    • 2002
  • In distributed computing environments, there are many database applications that should share data each other such as data warehousing and data mining with autonomy on local databases. The first step to such applications is the integration of heterogeneous database schema, but there is no accepted common data model for the integration and also are difficulties on the construction of integration program. In this paper, we use the XML Schema for the representation of common data model and exploit XSLT for reducing the programming difficulties. We define the schema integration operations and develop a methodology for the semi-automatic schema integration according to schema conflicts types. Our integration method has benefits on standardization, extendibility on schema integration process comparing to existing methodologies.

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A Model Management Framework for Supporting Departmental Collaborative Work (부서간 협동적 작업을 지원하는 모형관리 체계의 개발)

  • Huh, Soon-Young;Kim, Hyung-Min
    • Asia pacific journal of information systems
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    • v.10 no.2
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    • pp.51-69
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    • 2000
  • Recently, as business problems become more complicated and require more precise quantitative results, large-scale model management systems are increasingly in demand for supporting the decision-making activities. In addition, as distributed computing over networks gains popularity, departmental computing systems are gradually adopted in an organization to facilitate collaboration of geographically dispersed multiple departments. In departmental collaborative model management systems, multiple departments share common models but approach them with different user-views depending on their departmental needs. Moreover, the shared models become evolved as their structures and the corresponding data sets change due to the dynamic nature of the operating environment and the inherent uncertainty associated with the problems. In such capacity, providing the multiple departmental users with synchronized and consistent views of the models is important to improve the overall productivity. In this paper, we propose a collaborative model management framework for coordinating model change and automatic user-view update in a departmental computing environment. To do so, we describes changes in the model and their effects occurred in departmental model management environments and identifies the constructs and processes for maintaining the consistency between a shared model and its departmental user-views. Especially, in this framework, generic model concept was adopted for accommodating diverse mathematical models in a uniform way in a modelbase and object-oriented database management systems(ODBMS) for combining the model management constructs and automatic user-view update mechanisms in a single formalism. A prototype object-oriented modeling environment was developed using an ODBMS called ObjectStore and $C^{++}$ programming language on Windows NT.

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SecureJMoblet : Secure Mobile Agent System based on Jini2.0 (SecureJMoblet : Jini2.0 기반의 안전한 이동에이전트 시스템)

  • Yu Yang-Woo;Moon Nam-Doo;Lee Myung-Joon
    • The KIPS Transactions:PartA
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    • v.11A no.6
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    • pp.439-450
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    • 2004
  • Mobile agents are autonomous and dynamic entities that can migrate among various nodes in the network. Java's Jini framework facilitates mobile agent system development, providing hey features for distributed network programming. However, due to the security weakness, Jinil.0 service has a fundamental limitation on developing mobile agent systems which support secure remote communications. In this paper, we describe a Jini2.0-based secure mobile agent system named SecureJMoblet. On the top of Jini2.0, the system provides basic functionalities of a mobile agent system such as creation, transfer and control. In addition, with the SeureJS developed for secure JavaSpace service, SecureJMoblet supports a secure object repository and a reliable communication among mobile agents.

Optimal placement and tuning of multiple tuned mass dampers for suppressing multi-mode structural response

  • Warnitchai, Pennung;Hoang, Nam
    • Smart Structures and Systems
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    • v.2 no.1
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    • pp.1-24
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    • 2006
  • The optimal design of multiple tuned mass dampers (multiple TMD's) to suppress multi-mode structural response of beams and floor structures was investigated. A new method using a numerical optimizer, which can effectively handle a large number of design variables, was employed to search for both optimal placement and tuning of TMD's for these structures under wide-band loading. The first design problem considered was vibration control of a simple beam using 10 TMD's. The results confirmed that for structures with widelyspaced natural frequencies, multiple TMD's can be adequately designed by treating each structural vibration mode as an equivalent SDOF system. Next, the control of a beam structure with two closely-spaced natural frequencies was investigated. The results showed that the most effective multiple TMD's have their natural frequencies distributed over a range covering the two controlled structural frequencies and have low damping ratios. Moreover, a single TMD can also be made effective in controlling two modes with closely spaced frequencies by a newly identified control mechanism, but the effectiveness can be greatly impaired when the loading position changes. Finally, a realistic problem of a large floor structure with 5 closely spaced frequencies was presented. The acceleration responses at 5 positions on the floor excited by 3 wide-band forces were simultaneously suppressed using 10 TMD's. The obtained multiple TMD's were shown to be very effective and robust.

Research on Big Data Integration Method

  • Kim, Jee-Hyun;Cho, Young-Im
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.1
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    • pp.49-56
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    • 2017
  • In this paper we propose the approach for big data integration so as to analyze, visualize and predict the future of the trend of the market, and that is to get the integration data model using the R language which is the future of the statistics and the Hadoop which is a parallel processing for the data. As four approaching methods using R and Hadoop, ff package in R, R and Streaming as Hadoop utility, and Rhipe and RHadoop as R and Hadoop interface packages are used, and the strength and weakness of four methods are described and analyzed, so Rhipe and RHadoop are proposed as a complete set of data integration model. The integration of R, which is popular for processing statistical algorithm and Hadoop contains Distributed File System and resource management platform and can implement the MapReduce programming model gives us a new environment where in R code can be written and deployed in Hadoop without any data movement. This model allows us to predictive analysis with high performance and deep understand over the big data.

Comparing Energy Efficiency of MPI and MapReduce on ARM based Cluster (ARM 클러스터에서 에너지 효율 향상을 위한 MPI와 MapReduce 모델 비교)

  • Maqbool, Jahanzeb;Rizki, Permata Nur;Oh, Sangyoon
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2014.01a
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    • pp.9-13
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    • 2014
  • The performance of large scale software applications has been automatically increasing for last few decades under the influence of Moore's law - the number of transistors on a microprocessor roughly doubled every eighteen months. However, on-chip transistors limitations and heating issues led to the emergence of multicore processors. The energy efficient ARM based System-on-Chip (SoC) processors are being considered for future high performance computing systems. In this paper, we present a case study of two widely used parallel programming models i.e. MPI and MapReduce on distributed memory cluster of ARM SoC development boards. The case study application, Black-Scholes option pricing equation, was parallelized and evaluated in terms of power consumption and throughput. The results show that the Hadoop implementation has low instantaneous power consumption that of MPI, but MPI outperforms Hadoop implementation by a factor of 1.46 in terms of total power consumption to execution time ratio.

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Distributed Hybrid Simulation and Testing System using General-Purpose Finite Element Analysis Program (범용 유한요소해석 프로그램을 이용한 분산 공유 하이브리드 해석 및 실험 시스템)

  • Yun, Gun-Jin;Han, Bong-Koo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.1
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    • pp.59-71
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    • 2008
  • In this paper, a software framework that integrates computational and experimental simulation has been developed to simulate and test a large-scale structural system under earthquake loading. The proposed software framework does not need development of the computer codes for both dynamic and static simulations. Any general-purpose software can be utilized with a main control module and interface APIs. This opens up a new opportunity to facilitate use of sophisticated finite elements into hybrid simulation regime to enhance accuracy and efficiency of simulations. The software framework described in the paper is modular and uses object oriented programming concepts. A series of illustrative examples demonstrate that the system is fully-functional and is capable of running any number of experimental and/or analytical components.

Extending Caffe for Machine Learning of Large Neural Networks Distributed on GPUs (대규모 신경회로망 분산 GPU 기계 학습을 위한 Caffe 확장)

  • Oh, Jong-soo;Lee, Dongho
    • KIPS Transactions on Computer and Communication Systems
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    • v.7 no.4
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    • pp.99-102
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    • 2018
  • Caffe is a neural net learning software which is widely used in academic researches. The GPU memory capacity is one of the most important aspects of designing neural net architectures. For example, many object detection systems require to use less than 12GB to fit a single GPU. In this paper, we extended Caffe to allow to use more than 12GB GPU memory. To verify the effectiveness of the extended software, we executed some training experiments to determine the learning efficiency of the object detection neural net software using a PC with three GPUs.

Extracting Information from XML Documents by Reverse Generating DTDs (DTD 역 구성을 통한 XML문서에서의 정보추출)

  • 정종석;오동익
    • Journal of Korea Multimedia Society
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    • v.6 no.2
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    • pp.309-318
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    • 2003
  • XML documents are widely used for exchanging information in the distributed computing environment. Here, actual information contained in the document can only be interpreted with the provision of a proper DTD. However, XML documents collected from the web nay not always be accompanied by corresponding DTD, so that it may not be easy to extract information from such sources. In this study, we reverse construct a DTD from DTU-unknown XML sources. We then use the DTD to extract information from XML inputs and to store it into the underlying DB. The DTD construction module developed is designed in such a way that, it scans input XML files in 1-path, where most other implementations use 2-path approach. The information extraction module provides clean Java programming interfaces as well, so that it can be easily integrated with other web applications.

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Causal Replay for Cyclic Debugging of MPI Parallel Programs (MPI 병렬 프로그램의 순환 디버깅을 위한 인과관계 재실행)

  • Hong, Cheol-Eui;Kim, Yeong-Joon
    • Journal of KIISE:Computer Systems and Theory
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    • v.28 no.9
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    • pp.424-433
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    • 2001
  • The cyclic debugging approach often fails for message passing parallel programs because they non-deterministic characteristics due to message race conditions. This paper identifies the MPI events that affect non-deterministic executions, and then converts the concurrent execution to the sequential one that is controlled in order to make it equivalent to a reference execution by keeping their orders of events in two executions identical. This paper also presents an efficient algorithm for the causal distributed breakpoint which is initiated by any sequential breakpoint in one process, and restores each process to the earliest state that reflects all events that happened causally before the sequential breakpoint. So a cyclic debugging approach can be used in debugging MPI parallel programs as like as in debugging sequential programming environments.

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