• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.357-360
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• 2007

An asset tracking using wireless sensor network is concerned with geographical locations of sensor nodes. The limited size of sensor nodes makes them attractable for tracking service, at the same time their size causes power restrictions, limited computation power, and storage restrictions. Due to such constrained capabilities, the wireless sensor network basically assumes the failure of sensor nodes. This causes a set of concerns in designing asset tracking system on wireless sensor network and one of the most critical factors is location uncertainty of sensor nodes. In this paper, we classify the location uncertainty problem in asset tracking system into following cases. First, sensor node isn't read at all because of sensor node failure, leading to misunderstanding that asset is not present. Second, incorrect location is read due to interference of RSSI, providing unreliable location of asset. We implemented and installed our asset tracking system in a real environment and continuously monitored the status of asset and measured error rate of location of sensor nodes. We present experimental results that demonstrate the location uncertainty problem in asset tracking system using wireless sensor network.

• 산업경영시스템학회지
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• 제29권1호
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• pp.1-8
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• 2006

This paper proposes a real-time resource allocation algorithm for minimizing the completion time of overall workflow process. The jobs in a workflow process are interrelated through the precedence graph including Sequence, AND, OR and Loop control structure. A resource should be allocated for the processing of each job, and the required processing time of the job can be varied by the resource allocation decision. Each resource has several inherent restrictions such as the functional, geographical, positional and other operational characteristics. The algorithm suggested in this paper selects an effective resource for each job by considering the precedence constraint and the resource characteristics such as processing time and the inherent restrictions. To investigate the performance of the proposed algorithm, several numerical tests are performed for four different workflow graphs including standard, parallel and two series-parallel structures. In the tests, the solutions by the proposed algorithm are compared with random and optimal solutions which are obtained by a random selection rule and a full enumeration method respectively.

• 지적과 국토정보
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• 제45권1호
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• pp.193-205
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• 2015

입체공간에 대한 이용이 증가하면서 기존의 2차원 지적으로는 입체공간에 대한 정보를 관리하는데 한계가 있어 입체공간의 물리적 현황 및 사용권에 대한 정보를 등록 관리할 수 있는 3D 지적이 요구되고 있다. 이번 연구는 입체공간의 이용 현황 분석을 통해 3D 지적에 포함될 수 있는 데이터의 범위를 설정하고, 국제표준인 토지행정도메인모델(LADM)을 기반으로 3D 지적을 이해할 수 있는 개념모델을 설계함으로써 3D 지적시스템의 개발을 위한 기반을 마련하고자 한다.

• 한국정보처리학회논문지
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• 제2권5호
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• pp.634-644
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• 1995

본 논문에서는 세 가지 종류의 지식을 적절하게 표현하여 데이타베이스 시스템에 저장하고 이를 사용하여 질의를 의미적으로 등가이며 보다 처리 효율이 뛰어난 질의로 변환하는 기법을 제시하였다. 또한 제안된 지식을 사용하여 필수적인 성분이나 연산이 부분적으로 생략된 단순화된 질의를 완전한 질의로 변환할 수 있는 기법을 제시하여 사용자로 하여금 보다 단순화된 질의를 사용할 수 있는 환경을 제공하였다. 단순화된 질의로부터 변환과 최적화를 위해 다루는 지식은 크게 세 가지로 대별되는데, 의미적 무결성 규정과 도메인 무결성 규정을 포함하는 의미적 지식과 관계형 데이타베이스 에서의 릴레이션간의 물리적 관계를 표현하는 구조적 지식 그리고 속성의 도메인 정보 를 유지하는 도메인 정의이다. 제안된 시스템에서는 이들 지식을 사용하여 질의어의 조건 절에 있는 불필요하거나 중복적인 제한연산(restrictions)이나 조인연산(join) 을 제거하거나 다른 효율적인 연산으로의 대체, 혹은 보다 나은 효율을 위해 부가적인 제한연산이나 조인연산을 추가하여 질의 최적화를 이루게 된다.

• 정보처리학회논문지D
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• 제18D권5호
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• pp.313-316
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• 2011

다차원 데이터 집합에서 서로 지배되지 않는 데이터로 구성된 부분 집합을 스카이라인이라고 한다. 스카이라인 계산은 다차원 데이터를 대상으로 한 의사결정에 유용한 연산이다. 그러나 스카이라인이 지나치게 큰 경우 이를 의사결정에 활용하기 어려울 수 있다. 본 연구에서는 사용자가 제시하는 원점의 이동, 원점으로부터의 각도와 거리 정보를 반영하여 스카이라인의 일부를 효율적으로 구하는 방법을 모색하였다. 제안한 알고리즘은 스카이라인에 속하지 않는 데이터를 신속하게 제거해가며, 사용자의 요구를 점진적으로 반영할 수 있다는 특징을 갖는다. 알고리즘의 효율성은 실험을 통해 검증하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.293-303
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• 2011

Reliability Prediction using MIL-HDBK-217F has some restrictions due to its one modeling basis. One of the restrictions is caused by selecting one operating environment of a system, which is chosen regardless of its detailed conditions, e.g., external impact and vibration. Especially, an equipment, which is installed on a mobile vehicle though its movement is quasi-static, is controversial to designate its environment as ground mobile($G_M$), rather than ground fixed($G_F$). In this paper, failure rates were compared, which are computed using several moving time rates to total operating time. RiAC-HDBK-217Plus was used as the basic calculation model. In addition, $G_F$ conditioned failure rate was evaluated by comparing with that under $G_M$ environment but fixed state.

• 한국인터넷방송통신학회논문지
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• 제11권1호
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• pp.67-73
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• 2011

최근 스마트 폰 기술의 급속한 발전에 힘입어 모바일 컴퓨팅 환경에서의 온라인 게임의 설계에 대한 관심이 높아지고 있다. 그러나 모바일 단말인 스마트 폰은 비교적 낮은 성능의 프로세서, 저해상도의 GUI, 작은 메모리 공간과 짧은 배터리 파워 등의 제한으로 온라인 게임 구현에 많은 제약이 따른다. 따라서 대부분의 게임은 온라인이나 멀티 플레이 기능이 매우 제한적이다. 본 논문에서는 이러한 모바일 환경의 제약을 극복할 수 있는 컴포넌트 기반 스마트 폰 환경에서의 효율적인 모바일 온라인 게임 앱을 설계하고 구현하였다. 특히 본 논문에서 구현한 모바일 게임은 Wi-Fi를 기반으로 게임 서버와 다른 스마트 폰 간의 온라인 게임이 가능하도록 구현하였다.

• 약학회지
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• 제49권1호
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• pp.74-79
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• 2005

Metabonomic analysis has been recognized as a powerful approach for characterizing metabolic changes in biofluids due to toxicity, disease process or environmental influences. To investigate the possibility of relating metabolic changes with $^{1}H-NMR$ spectra, urine samples from Sprague-Dawley rats treated with various dietary restrictions or toxic substances (nicotine) were analysed using $^{1}H-NMR$ spectroscopy and pattern recognition techniques. Dietary restrictions-given to male rats were normal diet and high fat diet and fasting. The nicotine urine samples were collected from SD rats administered with nicotine (25 mg/kg) at the various time intervals. $^{1}H-NMR$ spectra of all urine samples were acquired at 400 MHz on a VARIAN spectrometer. To establish the presence of any intrinsic class-related patterns or clusters in each NMR data, methods of PCA (principal component analysis) and soft independent modeling of class analogy (SIMCA) analysis were used, and the results from these analyses were compared to each other. In all cases of dietary conditions and nicotine treatment, SIMCA analysis gave better results for the discrimination of NMR spectra of urine samples than PCA.

• 산업공학
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• 제18권2호
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• pp.136-147
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• 2005

This paper introduces a simulation study regarding the operation of the Painted Body Storage (PBS) in an automobile factory. In the paint shop of the factory, same colored bodies are grouped together in order to increase the effectiveness of process, for example decrease the loss of cleaning the painting-gun when the color of body changes from one to another. However the production of automobiles in the assembly shop is a typical example of the mixed model assembly production. Therefore PBS locates between the paint shop and the assembly shop for control the input sequence of bodies to the assembly shop, and it enables to meet the smoothing requirement of assembly sequence. There are highly restricted constraints on the assembly sequence in a assembly shop. Those are spacing restriction and smoothing restriction. If such restrictions are violated, conveyor-stop or utility work will be necessary. Thus the major objective of PBS is to control the assembly sequence in a way to meet the two restrictions. In this paper a case study of PBS in an automotive factory is introduced. The storage/retrieval algorithms are suggested and the proposed system is verified using simulation models. Sensitivity analysis for operating factors is also conducted.

• 한국군사과학기술학회지
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• 제17권4호
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• pp.544-550
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• 2014

In this paper, we have proposed a novel method which can analysis the direction finding ambiguity analysis for array geometry in 3 channel and 4 channel multiple baseline direction finding system. Generally, the direction finding ambiguity in the 3 element and 4 element phase interferometer direction finding system is calculated by the simulation for the array spacing or by the probability with the selected antenna array spacing. There are some restrictions to obtain the ambiguity of direction finding system in these methods. The former performs a simulation with every antenna array spacing and the latter calculates the ambiguity with the selected antenna array spacing. To overcome those restrictions, This paper proposed the novel method to calculate the ambiguity using the imaginary antenna array spacing and the phase difference prior to the modular operation in direction finder. Using the proposed method, we obtain the ambiguity probability for each of array geometry composed of multiple baseline. After performing the simulation with the selected antenna array spacing to verify the proposed method, we compared the calculated result data with the simulation data.