• Title/Summary/Keyword: analysis and computation

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In-network Distributed Event Boundary Computation in Wireless Sensor Networks: Challenges, State of the art and Future Directions

  • Jabeen, Farhana;Nawaz, Sarfraz
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.11
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    • pp.2804-2823
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    • 2013
  • Wireless sensor network (WSN) is a promising technology for monitoring physical phenomena at fine-grained spatial and temporal resolution. However, the typical approach of sending each sensed measurement out of the network for detailed spatial analysis of transient physical phenomena may not be an efficient or scalable solution. This paper focuses on in-network physical phenomena detection schemes, particularly the distributed computation of the boundary of physical phenomena (i.e. event), to support energy efficient spatial analysis in wireless sensor networks. In-network processing approach reduces the amount of network traffic and thus achieves network scalability and lifetime longevity. This study investigates the recent advances in distributed event detection based on in-network processing and includes a concise comparison of various existing schemes. These boundary detection schemes identify not only those sensor nodes that lie on the boundary of the physical phenomena but also the interior nodes. This constitutes an event geometry which is a basic building block of many spatial queries. In this paper, we introduce the challenges and opportunities for research in the field of in-network distributed event geometry boundary detection as well as illustrate the current status of research in this field. We also present new areas where the event geometry boundary detection can be of significant importance.

Topology-Hiding Broadcast Based on NTRUEncrypt

  • Mi, Bo;Liu, Dongyan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.1
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    • pp.431-443
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    • 2016
  • Secure multi-party computation (MPC) has been a research focus of cryptography in resent studies. However, hiding the topology of the network in secure computation is a rather novel goal. Inspired by a seminal paper [1], we proposed a topology-hiding broadcast protocol based on NTRUEncrypt and secret sharing. The topology is concealed as long as any part of the network is corrupted. And we also illustrated the merits of our protocol by performance and security analysis.

Parallel Computation Algorithm of Gauss Elimination in Power system Analysis (전력계통해석을 위한 자코비안행렬 가우스소거의병렬계산 알고리즘)

  • 서의석;오태규
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.2
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    • pp.189-196
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    • 1994
  • This paper describes a parallel computing algorithm in Gauss elimination of Jacobian matrix to large-scale power system. The structure of Jacobian matrix becomes different according to ordering method of buses. In sequential computation buses are ordered to minimize the number of fill-in in the triangulation of the Jacobian matrix. The proposed method develops the parallelism in the Gauss elimination by using ND(nested dissection) ordering. In this procedure the level structure of the power system network is transformed to be long and narrow by using end buses which results in balance of computing load among processes and maximization of parallel computation. Each processor uses the sequential computation method to preserve the sqarsity of matrix.

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Domain Decomposition using Substructuring Method and Parallel Computation of the Rigid-Plastic Finite Element Analysis (부구조법에 의한 영역 분할 및 강소성 유한요소해석의 병렬 계산)

  • Park, Keun;Yang, Dong-Yol
    • Transactions of Materials Processing
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    • v.7 no.5
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    • pp.474-480
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    • 1998
  • In the present study a domain decomposition scheme using the substructuring method is developed for the computational efficiency of the finite element analysis of metal forming processes. in order to avoid calculation of an inverse matrix during the substructuring procedure, the modified Cholesky decomposition method is implemented. As obtaining the data independence by the substructuring method the program is easily paralleized using the Parallel Virtual machine(PVM) library on a work-station cluster connected on networks. A numerical example for a simple upsetting is calculated and the speed-up ratio with respect to various number of subdomains and number of processors. The efficiency of the parallel computation is discussed by comparing the results.

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The Development of Static-explicit Rigid-plastic Finite Element Method and Application to 2-dimension Sectional Analysis (2차원 단면해석을 위한 정적-외연적 강소성 유한요소법의 개발 및 적용)

  • Jung, Dong-Won;Lee, Seung-Hun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.2
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    • pp.91-97
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    • 2003
  • In rigid-plastic finite element method, there is a heavy computation time and convergence problem. In this study, revised rigid-plastic finite element method Will be introduced. This method is the way that restrict the convergence interval. In result, convergence problem and computation time due to large non-linearity in the existing numerical analysis method were no longer a critical problem. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.

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Sensitivity Analysis Using a Symbolic Computation Technique and Optimal Design of Suspension Hard Points (기호계산을 이용한 현가장치의 민감도 해석 및 설계점의 최적 설계)

  • Chun, Hung-Ho;Tak, Tae-Oh
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4 s.97
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    • pp.26-36
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    • 1999
  • A general procedure for determining the optimum location of suspension hard points with respect to kinematic design parametes is presented. Suspensions are modeled as connection of rigid bodies by ideal kinematic joints. Constraint equations of the kinematic joints are expressed in terms of the generalized coordinates and hard points. By directly differentiating the constraint equations with respect to the hard points, kinematic sencitivity equations are obtained. In order to cope with algebraic complexity associated with the differentiation process, a symbolic computation technique is used. A performance index is defined in terms of static design parameters such as camber, caster, toe, ect.. Gradient of the performance index can be analytically computed from the kinematic sensitivity equations. Optimization results show the effectiveness and validity of the procedure, which is applicable to any type of suspension if its kinematic configurations are given.

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A Study on the Static Sensitivity Analysis Algorithm Using the Transfer of Stiffness Coefficient (강성계수의 전달을 이용한 정적 감도해석 알고리즘에 관한 연구)

  • Choi, Myung-Soo
    • Journal of Power System Engineering
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    • v.5 no.4
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    • pp.82-89
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    • 2001
  • To design a structural or a mechanical system with the best performance, the main procedure of a typical design usually consists of repeated modifications of design parameters and the investigation of the system response for each set of these parameters. But this procedure requires much time, effort and experience. Sensitivity analysis can provide systematic information for improving performance of a system. The author has studied on the development of the structural analysis algorithm and suggested recently the transfer stiffness coefficient method(TSCM). This method is very suitable algorithm to a personal computer because the concept of the TSCM is based on the transfer of the nodal stiffness coefficients which are related to force and displacement vectors at each node. In this paper, a new sensitivity analysis algorithm using the concept of the TSCM is formulated for the computation of state variable sensitivity in static problems. The trust of the proposed algorithm is confirmed through the comparison with the computation results using existent sensitivity analysis algorithm and reanalysis for computation models.

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An Analysis of Assessment Item on the Fraction Computation Ability for Fifth Grade Student (초등학교 5학년 학생들의 분수 연산능력 평가 문항에 대한 분석)

  • Lee Kang Sup;Kim Kyou Sang
    • Education of Primary School Mathematics
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    • v.8 no.2 s.16
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    • pp.61-68
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    • 2004
  • The purpose of this study is to develope and analyze the assessment items which can be used in evaluation of the fraction computation ability for fifth grade students. The item development team consists of three elementary school teachers and three mathematics education expert. The developed items was analyzed item analysis after applying to 135 fifth grade students. As a results of item analysis, it shows meaningful over the level of a standard basis: reliability: 0.80; validity: item 1(1.05), item 2(1.10), item 3(.85), item 4(.90), item 5(1.08); item difficulty: item 1(-.22), item 2(-.41), item 3(.23), item 4(.40), item 5(-.01); item discrimination: item 1(.73), item 2(.73), item 3(.67), item 4(.51), item 5(.56). This means that the test tool could be useful in the evaluation of the fraction computation ability.

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A study on electric field computation of dielectric analysis model with the conductivity on its surface (표면에 도전율을 갖는 유전체 해석모델의 전계계산에 관한 연구)

  • Kim, Hyeong-Seok;Lee, Ki-Sik;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1995.07a
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    • pp.6-8
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    • 1995
  • In this paper, we study the computation of the electric field of dielectric analysis models with the conductivity on its surface. The finite element formulation describes a sinusoidal electrodynamic field computation. One term is added to this functional in order to take the conductivity on its surface into accounts. The electric field computations of the dielectric analysis model are done first with the surface conductivity and second with the volume conductivity. Also, it is shown that a surface conductor with sufficiently large conductivity can be substituted with a floating equipotential line. This method is applied to an insulator in arbitrary shape with the conductivity on its surface.

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Axial and Flexural Coupled Free Vibration Analysis of a Branched Structure (Formulation by the Transfer Influence Coefficient Method) (분지를 갖는 구조물의 종.굽힘 연성 자유진동해석 (전달영향계산법에 의한 정식화))

  • 문덕홍;최명수;공석조
    • Journal of Advanced Marine Engineering and Technology
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    • v.16 no.5
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    • pp.29-38
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    • 1992
  • This paper describes the general formulation for the in-plane longitudinal and flexural coupled free vibration analysis of a branched structure. The branched structure, which is mainly found in machine tools, pipeline systems and so on, has some crooked parts and subsystems. And it modeled as a distributed mass system. The superiority of the present method to the transfer matrix method in the computation accuracy and speed was confirmed by the numerical computation results. Moreover, we comfirmed that boundary and intermediate conditions have been controlled by the spring constants.

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