• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5459-5473
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• 2017

Recently, a tracking algorithm called the spatial-temporal context model has been proposed to locate a target by using the contextual information around the target. This model has achieved excellent results when the target undergoes slight occlusion and appearance changes. However, the target location in the current frame is based on the location in the previous frame, which will lead to failure in the presence of fast motion because of the lack of a prediction mechanism. In addition, the spatial context model is updated frame by frame, which will undoubtedly result in drift once the target is occluded continuously. This paper proposes two improvements to solve the above two problems: First, four possible positions of the target in the current frame are predicted based on the displacement between the previous two frames, and then, we calculate four confidence maps at these four positions; the target position is located at the position that corresponds to the maximum value. Second, we propose a target reliability criterion and design an adaptive threshold to regulate the updating speed of the model. Specifically, we stop updating the model when the reliability is lower than the threshold. Experimental results show that the proposed algorithm achieves better tracking results than traditional STC and other algorithms.

• 에너지공학
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• 제24권1호
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• pp.17-23
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• 2015

전기식 출입문 시스템은 철도차량 영업운전에 영향을 주는 가장 중요한 시스템 중의 하나이다. 도시철도차량의 출입문은 승객들의 승하차를 담당하는 장치로써 고장이 발생할 경우 승객의 안전과 직접적인 영향을 미치기 때문에 열차운행에 영향을 미치는 중요한 장치이다. 최근에는 전기식 출입문 시스템의 신뢰도 목표값을 철도운영자가 철도차량 설계와 제작을 위한 발주사양 기술 요구조건에 포함하는 경향이 있으며, 차량 제작자는 제작시 발주사양기술 요구조건에서 철도운영자가 제시한 전기식 출입문 시스템의 신뢰도 목표값을 만족시켜야 하고, 철도운영자는 유지보수 데이터를 기반으로 공급자의 신뢰도 목표값 달성여부를 확인하고 승인하여야 한다. 본 연구에서는 전기식 출입문 시스템의 유지보수 현장 데이터를 수집하여 신뢰도를 미니탭 통계프로그램으로 분석하였다. 현장 데이터를 적용한 신뢰도 분석은 철도차량에 대한 새로운 유지보수 정책이나 유지보수 주기를 바꾸는데 매우 유용할 것이다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권3호
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• pp.162-168
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• 2014

This paper discusses the application of Bayesian techniques with test data on similar products for performing the Economical Reliability Test of new one-shot device. Using the test data on similar products, reliability test required lower sample size currently being spent in order to demonstrate a target reliability with a specified confidence level. Furthermore, lower sample size reduces cost, time and various resources on reliability test. In this paper, we use similarity as calculating weight of similar products and analyze similarity between new and similar product for comparison of the essential function.

• 산업기술연구
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• 제28권B호
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• pp.149-156
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• 2008

A reliability model of Level II AFDA is developed to analyze the stability of armor units on the sloped coastal structures. Additionally, the partial safety factors of random variables related to armor units can be straightforwardly evaluated by applying the inverse-reliability method in which influence coefficients and uncertainties of random variables, and target probability of failure are combined directly. In particular, a design equation for armor units is derived in terms of the same criteria as deterministic design method in order to apply the reliability-based design method of Level I without some understanding to the reliability analysis. Finally, it is confirmed that several results redesigned by the reliability-based design method of Level I have satisfactorily agreement with results of CEM as well as those of Level II AFDA.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 봄 학술발표회논문집
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• pp.135-140
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• 1993

The optimum weight design of structure is to determine the combination of structural members which minimize the weight of structures and satisfy design conditions as well. Since most of loads and design variables considered in structural design have uncertain natures, the reliability-based optimization techniques need to be developed. The aim of this study is to estabilish the general algorithm for the minimum weight design of transmission tower structure system with reliability constraints. The sequential linear programming method is used to solve non-linear minimization problems, which converts original non-linear programming problems to sequential linear programming problems. The optimal solutions are produced for various reliability levels such as reliability levels inherent in current standard transmission tower cross-section and optimal transmission tower cross-section obtained with constraints of current design criteria as well as selected target reliability index. The optimal transmission towers satisfying reliability constraints sustain consistent reliability levels on all members. Consequently, more balanced optimum designs are accomplished with less structural weight than traditional designs dealing with deterministic design criteria.

• 한국신뢰성학회지:신뢰성응용연구
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• 제3권1호
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• pp.41-58
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• 2003

Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability prediction methodologies that are applicable to machine tools. Especially ATC (Automatic Tool Changer) and Interface Card of PC-NC, which are core components of the machine tools, were chosen as the target of the reliability evaluation and analysis. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), and reliability for those components. It is expected that proposed methodologies will be applicable to evaluation of reliability for other industrial products.

• 한국정보통신학회논문지
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• 제13권3호
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• pp.445-450
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• 2009

소프트웨어를 개발하여 발행하기 전에 품질을 향상시키는 방법으로서 신뢰도를 향상시켜야 하는데, 이의 직접적인 방법으로서는 테스트에 의해 결함을 검출하고 수정해 가는 것이다. 신뢰도가 목표치에 도달하여 발행했을 때, 운영중의 신뢰도 문제가 발생하게 된다. 개발 발행된 소프트웨어 패키지소프트웨어라 불리는 범용소프트웨어냐, 아니면 특수목적을 가진 전용소프트웨어냐에 따라 운영 소프트웨어의 신뢰도가 달라진다. 본 논문에서는 범용소프트웨어와 전용소프트웨어의 운영중의 신뢰도를 산출하는 방법을 제안하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.677-680
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• 2003

Perceptual landmarks are an effective solution for a mobile robot realizing steady and reliable long distance navigation. But the prerequisite is those landmarks must be detected and recognized robustly at a higher speed under various lighting conditions. This made image processing more complicated so that its speed and reliability can not be both satisfied at the same time. Color based target detection technique can separate target color regions from non-target color regions in an image with a faster speed, and better results were obtained only under good lighting conditions. Moreover, in the case that there are other things with a target color, we have to consider other target features to tell apart the target from them. Such thing always happens when we detect a target with its single character. On the other hand, we can generally search for only one target for each time so that we can not make use of landmarks efficiently, especially when we want to make more landmarks work together. In this paper, by making use of the moment invariants of each landmark, we can not only search specified target from separated color region but also find multi-target at the same time if necessary. This made the finite landmarks carry on more functions. Because moment invariants were easily used with some low level image processing techniques, such as color based target detection and gradient runs based target detection etc, and moment invariants are more reliable features of each target, the ratio of target detection were improved. Some necessary experiments were carried on to verify its robustness and efficiency of this method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1525-1538
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• 2008

Currently, it has been a fashion to include RAMS of rolling stock in the order for purchasing the rolling stock. However, it's only to suggest a qualitative value or an ideal target without giving or demonstrating actual RAMS target, with only demonstrating passive RAMS by the data provided by the manufacturer. In the case of KTX project of 100 cars of KTX-II contracted in June 2006, their target has been suggested from the previous RAMS application standard and it aimed to achieve the reliability level of equivalent high speed rolling stock. Afterward, as actual KTX-II RAMS Plan and RAMS Demonstration Plan has been prepared and approved, it has been the first problem to secure the reliability and safety in order to introduce the new high speed rolling stock(KTX-II) successfully and we actually tried to apply overseas RAMS standard, KTX samples, electric railcar MTRC and rolling stock samples. This Report was dealt world trends of Railway RAMS standard, KTX-II RAMS Specifications, the present condition of KTX-II RAMS performance and development a way of KTX-II RAMS, We hope the "KTX-II RAMS Application Standard for Safety of Passenger Transportation Service" is served as an opportunity for the basic research for establishing and demonstrating RAMS target of components or parts composing the rolling stock system.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.90-97
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• 2016

Purpose: Majority of bridges and roads in Gangwon Province have been carrying loads associated with heavy materials such as rocks, mining products, and cement. This location-specific live loads have contributed to the present situation of overloading, compared to other provinces in Korea. However, the bridges in Gangwon province are designed by national bridge design specification, without considering the location-specific live load characteristics. Therefore, this study focuses on the real traffic data accumulated on regional weighing station to verify the live load characteristics, including actual live load gross vehicle weight, axle weight axle spacings, and number of trucks. Methods: In order to take into account the location specific live load, a governmental weigh station (38th national highway Miro) have been selected and the passing truck data are processed. Based on the truck survey, trucks are categorized into 3 different shapes, and each shape has been idealized into normal distribution. Then, the resulting survey data are processed to predict the target maximum live load values, including the axle loads and gross vehicle weights in 75 years service life span. Results: The results are compared to the nationally used DB-24 live loads, and the results show that nationally recognized DB-24 live load does not sufficiently represent real traffic in mountaineous region in Gangwon province. Conclusion: The comparison results in the recommendation of location-specific live load that should be taken into account for bridge design and evaluation.