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A Study on the Reliability Prediction for Space Systems (우주 시스템의 신뢰성 예측에 관한 연구)

  • Yu, Seung-U;Lee, Baek-Jun;Jin, Yeong-Gwon
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.227-239
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    • 2006
  • Reliability prediction provides a rational basis for design decisions such as the choice between alternative concepts, choice of part quality levels, derating factors to be applied, use of proven versus state-of-the-art techniques, and other factors. For this reasons, reliability prediction is essential functions in developing space systems. The worth of the quantitative expression lies in the information conveyed with the numerical value and the use which is made of that information and reliability prediction should be initiated early in the configuration definition stage to aid in the evaluation of the design and to provide a basis for item reliability allocation (apportionment) and establishing corrective action priorities. Reliability models and predictions are updated when there is a significant change in the item design availability of design details, environmental requirements, stress data, failure rate data, or service use profile. In this paper, the procedure, selection of reliability data and methods for space system reliability prediction is presented.

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Performance Modeling of an EPC Information Service System

  • Kim, So-Jung;Kang, Yong-Shin;Son, Kyung-Won;Lee, Yong-Han;Rhee, Jong-Tae;Hong, Sung-Jo
    • Industrial Engineering and Management Systems
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    • v.9 no.3
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    • pp.285-293
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    • 2010
  • To obtain visible and traceable information from the supply chain, HW/SW standards for the EPC global network, which process electronic product code (EPC) data read from Radio frequency identification (RFID) tags, are regarded as the de facto industry standard. Supply chain participants install information service systems and provide logistics information to partners by following the EPCglobal architecture framework. Although quality of service (QoS) is essential for providing dependable and scalable services as pointed out by Auto-ID Lab, only a few models for the performance analysis of QoS-related work have been developed in the context of EPC information service systems. Specifically, doing so allows alternative design choices to be tested in an easy and cost-effective manner and can highlight potential performance problems in designs long before any construction costs are incurred. Thus, in this study we construct a model of an EPC information service system for the purposes of performance analysis and designing a dependable system. We also develop a set of building blocks for analytical performance models. To illustrate how the model works, we determine the characteristics of an EPC information service system and then select a combination of these proven modeling concepts. We construct a performance model that considers the response time and shows how to derive meaningful performance values. Finally, we compare the analytical results to measurements of the EPC information service system.

Detection of Entry/Exit Zones for Visual Surveillance System using Graph Theoretic Clustering (그래프 이론 기반의 클러스터링을 이용한 영상 감시 시스템 시야 내의 출입 영역 검출)

  • Woo, Ha-Yong;Kim, Gyeong-Hwan
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.46 no.6
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    • pp.1-8
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    • 2009
  • Detecting entry and exit zones in a view covered by multiple cameras is an essential step to determine the topology of the camera setup, which is critical for achieving and sustaining the accuracy and efficiency of multi-camera surveillance system. In this paper, a graph theoretic clustering method is proposed to detect zones using data points which correspond to entry and exit events of objects in the camera view. The minimum spanning tree (MST) is constructed by associating the data points. Then a set of well-formed clusters is sought by removing inconsistent edges of the MST, based on the concepts of the cluster balance and the cluster density defined in the paper. Experimental results suggest that the proposed method is effective, even for sparsely elongated clusters which could be problematic for expectation-maximization (EM). In addition, comparing to the EM-based approaches, the number of data required to obtain stable outcome is relatively small, hence shorter learning period.

Investigation of Turbulence Structures and Development Turbulence Model Based upon a Higher Order Averaging Method (고차평균법에 의한 난류구조의 규명 및 난류모델의 개발)

  • 여운광;편종근
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.4 no.4
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    • pp.201-207
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    • 1992
  • The averaged non-linear term in the turbulence equations, suggested by Yeo (1987), is analyzed theoretically and experimentally. It was formulated by applying the filtering concepts to the convolution integral average definition with the Gaussian response function. This filtering approach seems to be superior to the conventional averaging methods in which all four terms at the doubly average vol must be defined separately, and it also gives a very useful tool in understanding the turbulence structures. By theoretically analyzing the newly derived description for the averaged non-linear terms, it is found that the vortex stretching can be explicitly accounted for. Furthermore, comparisons of the correlation coefficients based on the experimental data show that the vortex stretching acts most significantly on the turbulence residual stress. Thus, it strongly supports the claim that the vortex stretching is essential in the transfer of turbulence. In addition. a general form of turbulent energy models in LES is derived, by which it is recognized that the Smagorinsky, the vorticity and the SGS energy models are not distinctive.

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The Practice of Musical Stage Costume Production and the Role of the Stage Costume Designer - Focused on Case Studies of Domestic Small- and Medium-Sized Original Musical Productions - (뮤지컬 의상 제작의 실제와 의상 디자이너의 역할 - 국내 중소형 창작 뮤지컬 사례분석을 중심으로 -)

  • Park, Nae-Ri;Lee, Keum-Hee
    • The Research Journal of the Costume Culture
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    • v.20 no.1
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    • pp.18-35
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    • 2012
  • The purpose of this study is to offer a holistic description of the role demanded of costume designers to provide qualitative improvement of costume designs for small- and medium-sized musicals. The study accomplishes this by analyzing the relationship between the play and costume design in musicals and also by examining the process and environments in which costumes of small-sized theater companies' original musicals are produced. The methods of study are empirical research of literature related to dress, stage art, and culture & arts from both domestic and foreign publications; research of visual materials related to plays; and production and analysis of theatrical performances in which the researcher has participated as a costume designer. The results of the study are as follows. First, professionalism of the play and visual perfection of the work may be enhanced by costume designers actively participating in meetings with staff from each field of the play. Second, by taking advantage of the unique aspects of the work environment of small-sized theater companies' small- and medium-sized original musicals, such as harsh situations of regular and periodical meetings with all staff member, the designer may consider the director's intentions and concepts of the play, but should display more creative and autonomous design abilities. Third, because the costume designers of small- and medium-sized original musical plays are given a small budget and short production periods, the ability to systematically manage budget and production periods and the ability to flexibly handle unexpected incidents during the play is essential.

Public Administration Town Plan of Sejong-City based on Landscape Ecological Perspectives (경관생태학적 관점에서의 세종시 중심행정타운 조성계획)

  • Lee, Ai-Ran
    • Ecology and Resilient Infrastructure
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    • v.1 no.2
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    • pp.94-101
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    • 2014
  • This is the urban design master plan for the Public Administration Town. The project proposes a newly configured city, where environmental and democratic principles are expressed in the shape of the urban fabric. To achieve the goal, the concepts of 'Flat City, Link City, and Zero City' were introduced. These concept show "Space fabric arrange, connection and material circulation and flow from ecological landscape". 'Flat City' shaped the government buildings into an iconic plane, and democratic society. The iconic plane's surface extends across the whole city, creating an expansive public park, which is easily accessible, and open to nature. 'Link City' connects governmental agencies to enhance their function and interactions. Government facilities, parks and green spaces, cultural facilities, commercial zones, and residential districts areas create an interconnecting network. 'Zero City' has integrated infrastructure systems to reuse waste, reduce pollution, and provide essential city functions. It creates a new wildlife habitat, making 'Zero City' a good neighborhood. This proposal was made to integrate historical, regional, nature experiences with various approaches in architecture, city, and landscape architecture.

Valuation of Architecture-based Deterministic Plan for Software Evolution (아키텍처 기반의 결정적 소프트웨어 진화계획의 가치 평가)

  • Kang, Sung-Won;Garlan, David
    • The KIPS Transactions:PartD
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    • v.16D no.5
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    • pp.755-766
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    • 2009
  • Software architecture allows us to make many decisions about a software system and analyze it even before it exists in order to make systematic and planned development possible. Similarly, architecture-based software evolution planningmakes planned evolution possible by allowing us to make many decisions about evolution of a software system and analyze its evolution at the level of architecture design before software evolution is realized. In this paper, we develop a framework for architecture-based software evolution planning for the class of deterministic evolution plans by defining and relating various essential concepts and developing its valuationmechanism so that a plan with the greatest value among candidate plans can be selected as an optimal plan. A case study is conducted for explicating the framework and exemplifying its usage.

The Effects of Apartment Brand Image Characteristics on Purchase Intention (아파트 브랜드이미지 특성이 구매의도에 미치는 영향에 관한 실증연구)

  • Moon, Hyogon
    • Land and Housing Review
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    • v.4 no.3
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    • pp.235-241
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    • 2013
  • There have been a lot of previous studies that brand image has a positive impact on purchase as well as the value enhancement of the product with the spread of brand importance and the introduction of brand in the apartment. This study verified that brand image can be factorized and separated into two factors - basic characteristics and additional characteristics. The basic characteristics means essential parts that generally should be provided for housing and the additional characteristics are competitively developed concepts introduced by construction companies for sales promotion. The results of the empirical analysis that verified the effects of the two factors on purchase intention are as follows. The basic characteristics have the positive impact on purchase intention while the additional characteristics are otherwise. This result suggests that it is more important to be faithful to the basics than to be competitively differentiated by the additional characteristics in the apartment market.

Related Factors for the Initiation of Smoking in High School Students Based on the Transtheoretical Model (범이론적 모형에 근거한 고등학생의 흡연시작 관련요인)

  • Hong, Jee-Young;Na, Baeg-Ju;Kim, Keon-Yeop;Lee, Moo-Sik
    • Journal of Preventive Medicine and Public Health
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    • v.39 no.1
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    • pp.67-73
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    • 2006
  • Objective: This study was conducted to investigate the relationship between the intention of smoking and its related factors in high school students. Methods: Our study subjects were 1,203 high school students who resided in one city and in one county region. We conducted a self-administered questionnaire survey from June 7 to June 19, 2004. Both the decisional balance and temptation inventory showed high reliability estimates. We provided good fit for the 12-item decisional balance inventory and the 10-item temptation inventory by using a confirmatory factor analysis. We also used multiple logistic regression analysis to identify the major contributing factors for the intention to start smoking. Results: On the univariate analysis, the subjects who were female, the 2nd and 3rd grade students, the students in vocational high school, the ex-drinkers or current drinkers, and ex-smokers were found to be significantly more distributed in the groups with intention to start smoking. Except for the concept of the cons, the group with intention to start smoking showed significantly higher standardized T scores for the 7 concepts of decisional balance and temptations. On the multiple logistic regression analysis, the females, the 2nd and 3rd grade students, the students in vocational high school, the experience of cigarette smoking and low T score of the cons were significantly related to the intention to start smoking. Conclusions: The intention to start smoking in high school students was affected by various factors such as gender, the school grade and the experience of smoking. Therefore, further research should be conducted for providing the essential data for developing a brief instrument for selecting the groups with intention of starting smoking among adolescents.

Range Query Processing using Space and Time Filtering in Fixed Grid Indexing (고정 그리드 인덱싱에서 공간과 시간 필터링을 이용한 범위 질의 처리)

  • Jeon, Se-Gil;Nah, Yun-Mook
    • The KIPS Transactions:PartD
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    • v.11D no.4
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    • pp.835-844
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    • 2004
  • Recently, the location-based service for moving customers is becoming one of the most important service in mobile communication area. For moving object applications, there are lots of update operations and such update loads are concentrated on some particular area unevenly. Range queries, whose range can be window or circular, are the most essential query types in LBS. We need to distinguish completely contained cells from partially contained cells in those range queries. Also, it is necessary to consider temporal dimension to filter out qualifying objects correctly. In this paper, we adopt two-level index structures with fixed grid file structures in the second level, which are designed to minimize update operations. We propose a spatial ceil filtering method using VP filtering and a combined spatio-temporal filtering method using time gone concepts. Some experimental results are shown for various window queries and circular queries with different filtering combinations to show the performance tradeoffs of the proposed methods.