• 대한수학회지
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• 제58권3호
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• pp.723-740
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• 2021

Design and maintenance of large span roof structures require an analysis of their static and dynamic behavior depending on the physical parameters defining the structures. Therefore, it is highly desirable to estimate the parameters from observations of the system. In this paper we study the parameter estimation problem for damped shallow arches. We discuss both symmetric and non-symmetric shapes and loads, and provide theoretical and numerical studies of the model behavior. Our study of the behavior of such structures shows that it is greatly affected by the existence of critical parameters. A small change in such parameters causes a significant change in the model behavior. The presence of the critical parameters makes it challenging to obtain good estimation. We overcome this difficulty by presenting the Parameter Estimation Algorithm that identifies the unknown parameters sequentially. It is shown numerically that the algorithm achieves a successful parameter estimation for models defined by arbitrary parameters, including the critical ones.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.125-130
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• 2021

Scaffold is used to produce bio sensor. Scaffold is required high dimensional accuracy. 3D printer is used to manufacture scaffold. 3D printer can't detect defect during printing. Defect detection is very important in scaffold printing. Real-time defect detection is very necessary on industry. In this paper, we proposed the method for real-time scaffold defect detection. Real-time defect detection model is produced using CNN(Convolution Neural Network) algorithm. Performance of the proposed model has been verified through evaluation. Real-time defect detection system are manufactured on hardware. Experiments were conducted to detect scaffold defects in real-time. As result of verification, the defect detection system detected scaffold defect well in real-time.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.981-984
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• 2009

본 논문에서는 수정된 유클리드 알고리즘을 이용하여 RS(255,239) 복호기를 설계하였다. 설계된 복호기는 수정된 유클리드 알고리즘에서 차수를 계산하는 대신, 다항식의 차수를 state machine으로 표현한다. 수정된 유클리드 알고리즘을 이용하여 복잡도를 감소시킬 수 있고, 고속의 리드-솔로몬 복호기를 구현할 수 있다. Xilinx FPGA인 XC4VLX60을 타겟으로 ISE9.1i에서 합성한 결과 동작주파수가 77.4MHz이며, gate count가 39,759로 나타났다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.873-875
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• 2008

센서 네트워크의 위치추정의 정밀도를 높이기 위해서는 NLOS신호의 제거가 필수적이다 따라서 본 논문에서는 위치추정의 정밀도를 높이는 방안으로 NLOS부터 수신한 신호로 추정한 좌표를 반복적으로 제거하는 알고리즘을 제안하였고 이를 시뮬레이션 하여 성능을 검증하였다. 제안한 알고리즘을 사용하였을 경우 10개의 LOS 신호로 추정한 좌표를 가지고 최대 약 3.5미터의 오차범위 내로 위치 추정을 할 수 있음을 확인하였고, NLOS 좌표의 감소에 따라서도 약 1.5미터의 위치추정 정밀도를 향상시킬 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.857-860
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• 2008

본 논문에서는 센서 노드의 위치를 추정하기 위해 서로 다른 센서노드의 신호세기를 기록한 RSS table을 활용하여 노드가 존재하는 영역을 추정하고, 해당 영역에 속하지 않는 공간을 순차적으로 제거하는 cooperative localization 알고리즘을 제안한다. 각각의 센서노드는 신호세기를 모니터링 하고, 신호세기의 범위에 따라 센서노드의 존재 가능 영역을 배제하게 되며 최종적으로 존재 가능 영역의 중심(centroid)을 노드의 위치로 추정하게 된다. 이러한 과정은 RSS table에 기록된 모든 노드들에 대해 반복적으로 적용되고 이를 통해 미지의 노드들에 대한 정밀한 위치추정이 가능하다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.65-68
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• 2001

Short shot is a molded part that is incomplete since insufficient material was injected into the mold. Remedial actions to solve short shot can be done by injection molding experts based on their empirical knowledge. Modifying mold and part, changing resin to less viscous one, and adjusting process conditions are general remedies. Experts of injection molding might try to adjust process conditions such as mold temperature, melt temperature, injection time based on their empirical knowledge as the first remedy because adjustment of process conditions is the most economic way in time and cost. However it is difficult to find appropriate process conditions as they are highly coupled and there are so many elements to be considered. In this paper, a fuzzy logic algorithm has been proposed to find an appropriate mold temperature. With the percentage of the insufficient Quantity of an injection molded part, an appropriate mold temperature can be obtained by the fuzzy logic algorithm.

• 컴퓨터교육학회논문지
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• 제14권4호
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• pp.43-51
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• 2011

IT기술의 발전으로 인해 언제 어디서나 다양한 정보를 제공 받을 수 있는 정보화 시대가 도래하였지만, 이에 대한 역기능으로 원하지 않는 개인정보 유출 피해가 증가하고 있다. 이러한 개인정보 유출 피해를 방지하기 위해서 사용되는 기본적인 학문이 암호학이다. 하지만 암호학은 복잡한 수학적 이론이 접목되어 있는 학문이기 때문에 많은 사람들이 학습에 많은 어려움을 겪고 있다. 따라서 본 논문에서는 암호학에 대한 이해를 개선하기 위해 일반적으로 전자 서명에서 주로 사용되고 있는 RSA 암호 알고리즘에 대한 지식을 향상 시키는데 도움을 줄 수 있는 소프트웨어를 개발하였다. 개발한 소프트웨어를 통해 RSA 암호 알고리즘의 동작 방식에 대한 이해를 돕고자 한다.

• 한국공간구조학회논문집
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• 제15권2호
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• pp.87-94
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• 2015

This paper aimed at modeling a fine triangular grid for network dome by using Harmony Search (HS) algorithm. For this purpose, an optimization process to find a fine regular triangular mesh on the curved surface was proposed and the analysis program was developed. An objective function was consist of areas and edge's length of each triangular and its standard deviations, and design variables were subject to the upper and lower boundary which was calculated on the nodal connectivity. Triangular network dome model, which was initially consist of randomly irregular triangular mesh, was selected for the target example and the numerical result was analyzed in accordance with the HS parameters. From the analysis results of adopted model, the fitness function has been converged and the optimized triangular grid could be obtained from the initially distorted network dome example.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3126-3145
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• 2014

Cloud computing is a computing paradigm in which users can rent computing resources from service providers according to their requirements. A spot instance in cloud computing helps a user to obtain resources at a lower cost. However, a crucial weakness of spot instances is that the resources can be unreliable anytime due to the fluctuation of instance prices, resulting in increasing the failure time of users' job. In this paper, we propose a Genetic Algorithm (GA)-based workflow scheduling scheme that can find the optimal task size of each instance in a spot instance-based cloud computing environment without increasing users' budgets. Our scheme reduces total task execution time even if an out-of-bid situation occurs in an instance. The simulation results, based on a before-and-after GA comparison, reveal that our scheme achieves performance improvements in terms of reducing the task execution time on average by 7.06%. Additionally, the cost in our scheme is similar to that when GA is not applied. Therefore, our scheme can achieve better performance than the existing scheme, by optimizing the task size allocated to each available instance throughout the evolutionary process of GA.

• Journal of Information Processing Systems
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• 제14권6호
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• pp.1347-1360
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• 2018

Owing to limited energy in wireless devices power saving is very critical to prolong the lifetime of the networks. In this regard, we designed a cross-layer optimization mechanism based on power control in which source node broadcasts a Route Request Packet (RREQ) containing information such as node id, image size, end to end bit error rate (BER) and residual battery energy to its neighbor nodes to initiate a multimedia session. Each intermediate node appends its remaining battery energy, link gain, node id and average noise power to the RREQ packet. Upon receiving the RREQ packets, the sink node finds node disjoint paths and calculates the optimal power vectors for each disjoint path using cross layer optimization algorithm. Sink based cross-layer maximal minimal residual energy (MMRE) algorithm finds the number of image packets that can be sent on each path and sends the Route Reply Packet (RREP) to the source on each disjoint path which contains the information such as optimal power vector, remaining battery energy vector and number of packets that can be sent on the path by the source. Simulation results indicate that considerable energy saving can be accomplished with the proposed cross layer power control algorithm.