• 한국신뢰성학회지:신뢰성응용연구
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• 제17권2호
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• pp.112-121
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• 2017

Purpose: The most previous works on designing accelerated life tests (ALTs) are focused on the application of a single stress. Because of the difficulty to obtain the sufficient information in a reasonable duration using single stress only, there is needed in practice to use multiple-stress ALTs frequently. This paper presents new practical plans with two stresses for Weibull distribution. Methods: The four-level practical plans based on rectangle test region are proposed and compared with the corresponding three-level statistically optimal plans. Sensitivity analyses for assumed design parameters and life-stress relationship are conducted. Results: A procedure to choose practical ALT plans is illustrated with a numerical example and guidelines for planning two-stress ALTs are provided. Conclusion: The proposed two-stress ALT plans on practical constraints to assess a quantile of Weibull lifetime distribution at the use condition are efficient and robust.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.910-915
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• 2004

The objective of this study is to investigate the influence of process parameters, such as power of laser, travel speed of laser and material thickness, on the practical cutting region and the kerfwidth for the case of cutting of CSP 1N sheet using high power Nd:YAG laser with continuous wave(CW). In order to find the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and travel speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth for the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensional accuracy of the cut area.

• 한국정밀공학회지
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• 제22권7호
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• pp.19-26
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• 2005

The objective of this study is to investigate the influence of process parameters, such as power of laser, cutting speed of laser and material thickness, on the practical cutting region and the kerfwidth fer the case of cutting of CSP IN sheet using high power Nd:YAC laser in continuous wave(CW) mode. In order to obtain the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and cutting speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth fur the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensionalaccuracyofthecutarea.

• 전기전자학회논문지
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• 제23권1호
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• pp.302-305
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• 2019

Non-orthogonal multiple access (NOMA) has been considered for the fifth generation (5G) mobile networks to provide high system capacity and low latency. We calculate the channel capacity for the weak channel user in NOMA and the channel capacity region for NOMA. In this paper, Gaussian mixture channel is compared to the additive white Gaussian noise (AWGN) channel. Gaussian mixture channel is modeled when we assume the practical signal modulation for the inter user interference, such as the binary phase shift keying (BPSK) modulation. It is shown that the channel capacity with BPSK inter user interference is better than that with Gaussian inter user interference. We also show that the channel capacity region with BPSK inter user interference is larger than that with Gaussian inter user interference. As a result, NOMA could perform better in the practical environments.

• 한국인터넷방송통신학회논문지
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• 제12권6호
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• pp.155-164
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• 2012

개발인력을 투입하는 양에 상관없이 소프트웨어를 개발하는데 소요되는 일정 단축에는 한계가 있다. 그러나 획득되는 실제 개발된 소프트웨어 데이터들을 분석하여 보면 불가능한 단기간의 개발기간 또는 비현실적으로 장기간 개발기간 데이터들까지 포함하고 있다. 기존에 제안된 개발기간 추정 모델들은 이러한 제약사항을 고려하지 않고 실제 개발된 소프트웨어 모두를 대상으로 개발일정을 유도하고 있다. 본 논문은 개발 최소기간과 최적 개발기간(정상적인 개발기간)에 대한 기준을 제시한다. 제시된 기준은 실제 수행된 프로젝트를 대상으로 5개의 기준 중에서 가장 성능이 좋은 개발기간 추정 모델을 얻은 기준을 판단하였다. 또한, 이에 기반하여 개발기간을 추정하는 모델을 제시한다.

• 디지털융복합연구
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• 제15권12호
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• pp.13-23
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• 2017

오늘날 '정보화사회' 구축은 국가경쟁력 획득에 중요한 수단이 된다. 특히, 우리나라는 전 세계적으로 성공적인 정보화 구축 대표 사례로 평가 받고 있다. 이와는 반대로 북한은 심각한 '정보격차' 문제로 인해 그렇지 못한 실정이다. 이러한 정보격차의 발생원인으로는 세 가지 측면이 있다. 첫째, 매체접근성, 둘째, 정보동원력, 셋째, 정보의식이다. 이러한 세가지 측면을 바탕으로 통일 이후 북한지역의 정보화 구축 과정에 대해 설계 제안한다. 본 연구의 목적은 통일시대를 대비해 어떻게 북한 지역의 정보화 구축을 할 것인가에 대해 단계별 실행 전략을 도출하고자 한다. 이를 위해 우리나라와 북한의 정보화 구축 단계들을 각각 살펴보고 추진과정을 분석하였다. 본 연구에서 제시한 실행전략이 향후 연구에 있어서 거대한 담론을 일으키는 초석이 될 수 있을 것으로 기대한다.

• 한국지역사회생활과학회지
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• 제16권3호
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• pp.57-64
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• 2005

The purpose of this study was to compare clothing attitudes and the criteria for clothing selection between Korean and Korean-Chinese college female students in the Yanbian region of China. The subjects were selected as follows: 404 Korean female college students in the Choongchung area and 242 Korean-Chinese female college students in the Yanbian region of China. Questionnaires were used to collect the data and the data was analyzed by frequency, factor analysis, and t-test. The major results of this study were as follows: The clothing attitudes of the total respondents were classified into 5 factors: the fashion involving factor, the modesty involving factor, the economy conscious factor, the brand-name oriented factor, and the practical user factor. The modesty involving factor, the economy conscious factor, the brand-name oriented factor, and the practical user factor were significantly different between Korean and Korean-Chinese college female students. Korean consumers thought highly of the economy conscious factor and the practical user factor compared with Korean-Chinese college female students. However, Korean-Chinese college female students thought highly of the brand-name oriented factor and the modesty factor compared with Korean consumers.

• 대한기계학회논문집A
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• 제25권12호
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• pp.2009-2018
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• 2001

This paper presents a region offsetting algorithm for tool-path generation. The proposed region offsetting algorithm is developed by expanding the 'PWID offset algorithm [Choi and Park, 1999]'designed to offset a simple polygon. The PWID offset algorithm has three important steps; 1) remove 'local invalid ranges'by invoking a PWID test, 2) construct a raw offset owe and 3) remove 'global invalid ranges'by finding self-intersections of the raw offset cure. To develop a region offsetting algorithm, we modified the PWID offset algorithm by expanding the concept of the 'global invalid range'in the third step. The time complexity of the proposed algorithm is approximately Ο(n), where n is the number of points, and it is free of numerical errors for practical purposes. The proposed algorithm has been implemented and tested with various real regions obtained by intersecting a sculptured surface with a plane.

• 한국통신학회논문지
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• 제23권9A호
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• pp.2333-2344
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• 1998

We present a two step approach for estimating the motionand sturcture parameters from region orrespondences in two frames. Given four or more region corresondences on the same planar surface, the motion and planar orientation parameters are first linearly estimated based on second-order approximation of the displacement field of the image plane. Then, using this linear estimate as an initial guess, a nonlinear estimate is obtained by iteratively minimizing an objective function using the exact experession of the displacement field. The objective function involves the centroids of corresponding regions and relationships among low-order moments. Through simulations, we show that the two-step region-based approach gives robust estimates. The performance of nonlinear region-based estimation is compared with that of linear region-based and point-based methods. Experimental results for two image pairs, on esynthetic and one real, ar epresented to show the practical applicability of our approach.

• 한국조경학회지
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• 제27권5호
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• pp.57-65
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• 2000

Vernacular embodies a culture and economy that are unique to one particular region at a given period, expressed in the lifestyles of the ordinary people of the region. This study aims at interpreting Korean Vernacular Landscape by applying the analytical tool thus developed to the lifestyles of ordinary people found in their permanent dwellings (e. g., villages). By so doing, this study hopes to contribute to building a framework with which to understand the tradition of ordinary people by exploring the uniqueness and basic characteristics of Korean Vernacular Landscape. This study relies primarily on filed studies on, and publications relating to, the agrarian and residential landscapes. The Korean vernacular landscape has not only crude and simple generality, but also individuality derived from cultural circumstances and natural feature. Korean Vernacular Landscape may be characterized as the practical Vernacular Landscape, consisting of the raw materials that were only available in a particular region, shaped by the terrain, and maintained by the customs that varied from a region to a region.