• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.6
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• pp.616-625
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• 2011

Ensuring the designed prestress force is very important for the safety of prestressed concrete bridge. The loss of prestress force in tendon could significantly reduce load carrying capacity of the structure. In this study, an automated prestress-loss monitoring system for prestressed concrete girder using PZT-interface and wireless impedance sensor node is presented. The following approaches are carried out to achieve the objective. Firstly, wireless impedance sensor nodes are designed for automated impedance-based monitoring technique. The sensor node is mounted on the high-performance Imote2 sensor platform to fulfill high operating speed, low power requirement and large storage memory. Secondly, a smart PZT-interface designed for monitoring prestress force is described. A linear regression model is established to predict prestress-loss. Finally, a system of the PZT-interface interacted with the wireless sensor node is evaluated from a lab-scale tendon-anchorage connection of a prestressed concrete girder.

• 전기의세계
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• v.30 no.6
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• pp.375-385
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• 1981

New algorithms are derived for nonlinear programming problems which are characterized by their large variables and equality and inequality constraints. The algorithms are based upon the introduction of the Dependent-Variable-Elimination method, Independent-Variable-Reduction method, Optimally-Ordered-Triangular-Factorization method, Equality-Inequality-Sequential-Satisfaction method, etc. For a case study problem relating to the optimal determination of load flow in a 10-bus, 13-line sample power system, several approaches are undertaken, such as SUMT, Lagrange's Multiplier method, sequential applications of linear and quadratic programming method. For applying the linear programming method, the conventional simplex algorithm is modified to the large-system-oriented one by the introduction of the Two-Phase method and Variable-Upper-Bounding method, thus resulting in remarkable savings in memory requirements and computing time. The case study shows the validity and effectivity of the algorithms presented herein.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.135-136
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• 2018

CoAP을 사용하는 IoT 기기는 핸드오버를 시행하는 동안 주기적으로 보내야 하는 메시지를 보내지 않고 메모리에 저장한다. 그로 인한 경량 IoT 기기의 메모리 요구량의 감소를 위한 핸드오버 절차를 제안한다. 제안하는 절차에서는 센서 노드가 핸드오버 이전에 현재 기지국에 미리 핸드오버 요청을 보낸다. 따라서 센서 노드가 이웃한 기지국에게 핸드오버 요청을 했을 때, 이웃한 기지국은 현재 기지국에게 핸드오버 알림을 주지 않는다. 본 연구에서는 시뮬레이션을 통하여 제안하는 핸드오버 절차로 인한 observe 메시지의 메모리 점유율을 50%가량 줄인다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.27-36
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• 1993

This paper proposes a shortest path allocation algorithm over the processors on the hypercube system based on the message passing techniques with the optimized module allocation. On multiprocessor systems, how to divide one task into multiple tasks efficiently is an important issue due to the hardness of the life cycle estimation of each process. To solve the life cycle discrepancies, the appropriate task assignment to each processor and the flexible communications among the processors are indispensible. With the concurrent program execution on hypercube systems, each process communicaties to others with the method of message passing. And, each processor has its own memory. The proposed algorithm generates a callable tree out of the module, assigns the weight factors, constructs the allocation graph, finds the shortest path allocation tree, and maps them with hypercube.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.7
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• pp.1020-1027
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• 2000

A simple model for describing the non-spherical particle growth phenomena has been developed. In this model, we solve simultaneously particle volume and surface area conservation sectional equations that consider particles' non-sphericity. From the correlation between two conserved properties of sections, we can predict the evolution of the aggregates' morphology. This model was compared with a simple monodisperse-assumed model and more rigorous two-dimensional sectional model. For comparison, formation and growth of silica particles have been simulated in a constant temperature reactor environment. This new model showed good agreement with the detailed two-dimensional sectional model in total number concentration and primary particle size. The present model successfully predicted particle size distribution and morphology without costing very heavy computation load and memory needed for the analysis of two dimensional aerosol dynamics.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1489-1495
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• 1995

In this paper, we propose recurrent neural prediction models (RNPM), recurrent neural networks trained as a nonlinear predictor of speech, as a new connectionist model for speech recognition. RNPM modulates its mapping effectively by internal representation, and it requires no time alignment algorithm. Therefore, computational load at the recognition stage is reduced substantially compared with the well known predictive neural networks (PNN), and the size of the required memory is much smaller. And, RNPM does not suffer from the problem of deciding the time varying target function. In the speaker dependent and independent speech recognition experiments under the various conditions, the proposed model was comparable in recognition performance to the PNN, while retaining the above merits that PNN doesn't have.

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.901-911
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• 2015

The goal of this study is to investigate computational convergence of optimal solutions, with respect to optimality criteria (OC) method and methods of moving asymptotes (MMA) as optimization model for non-linear programming of material topology optimization using an acceleration method that makes design variables rapidly move toward almost 0 and 1 values. 99 line topology optimization MATLAB code uses loop vectorization and memory pre-allocation as properly exploiting the strengths of MATLAB and moves portions of code out of the optimization loop so that they are only executed once as restructuring the program. Numerical examples of a simple beam under a lateral load and a given material density limitation provide merits and demerits of the present OC and MMA for 99 line topology optimization code of continuous material topology optimization design.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.385-387
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• 2003

본 논문에서는 이질적인 클러스터 컴퓨팅시스템 에서 CPU와 메모리 자원을 효율적으로 사용하는 작업 부하 균등화 정책을 제안한다. 이 정책의 특징은 CPU부하 상태와 수행중인 작업의 메모리 요구량을 고려하여 작업을 동적으로 할당하는 것이다. 먼저 각 노드는 CPU와 메모리 사용량에 따라 과부하 상태가 아니면 작업을 할당받아 수행한다. 그리고 수행중인 작업의 메모리 요구량이 가용 메모리 크기를 초과하여 페이지 폴트가 발생하면 수행 중인 작업을 다른 노드로 이주시킴으로써 메모리 과부하에 따른 페이지 폴트 발생을 줄이고, 작업의 대기 시간과 수행시 간을 단축한다. 본 논문에서는 시뮬레이션을 통하여 제안한 작업부하 균등화 정책이 기존의 CPU 기반정책에 비해 시스템의 성능향상 면에서 유리함을 검증한다.

• Structural Engineering and Mechanics
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• v.22 no.1
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• pp.33-52
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• 2006

Three-dimensional description of building structure taking into consideration soil-structure interaction is a very complex problem and solution of this problem is often obtained by using finite element method. However, this method takes a significant amount of computational time and memory. Therefore, an efficient computational model based on subdivision of the structure into building elements such as wall and floor slab elements, plane and three-dimensional joints and lintels, that could provide accurate results with significantly reduced computational time, is proposed in this study for the analysis three-dimensional structures subjected to dynamic load. The examples prove the efficiency and the computing possibilities of the model.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.20-23
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• 2020

도커는 하드웨어 가상화를 지원하는 KVM과 달리 호스트의 커닐을 공유하기 때문에 보안적인 문제가 생길 수 있다. 또한, 도커는 호스트 OS에 종속적이기 때문에 다른 OS에 종속적인 컨테이너를 실행할 수 없다는 단점도 있다. 이를 보완하기 위해 KVM을 이용해 가상머신을 실행하고 가상머신에서 도커를 이용하면 도커와 KVM의 장점을 살린 시스템을 구성할 수 있다. 실제 이 시스템의 실효성과 안정성을 평가하기 위해 실험을 진행하였고, 호스트의 메모리만 충분하다면 실효성과 안정성이 보장됨을 확인하였다.