• 한국전산구조공학회논문집
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• 제28권3호
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• pp.229-239
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• 2015

국내 수출입 물동량의 증가와 해운산업의 발달에 따라 항만시설물의 사용빈도 또한 증가 추세에 있으나, SOC의 해운항만부문의 투입 정부예산은 감축되어 왔다. 증가하는 사용빈도에 반하여 줄고 있는 예산으로 인해 항만시설물의 체계적이고 효율적인 유지관리 및 운영이 필요하다. 효율적인 유지관리 시스템 구축을 위해서 항만시설물이 위치한 지역, 구조물의 형태 및 취급화종, 시공 및 유지관리 수준과 같은 특성을 고려한 열화모델 개발이 필요하다. 항만시설물의 열화모델 개발은 시설물의 열화요인 분석과 열화데이터 수집 및 열화 모델 개발의 과정으로 수행하였다. 열화 모델 개발기법은 변수 특성에 따른 시간 의존적 상태변화를 반영할 수 있는 결정론적 방법인 다중 회귀분석과 변동성이 큰 자료들의 상태이력을 반영할 수 있는 확률론적 방법인 마코브 체인 이론을 이용하였다. 각 방법을 통해 잔교식 구조물과 블록식 구조물의 Project level의 상태 열화모델을 제시하였다.

• Journal of Korea Trade
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• 제25권3호
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• pp.65-86
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• 2021

Purpose - This paper empirically investigates the relationship between the corporate value chain and performance of non- financial businesses of South Korean stock market companies. It aims to explore the evidence that can be used to infer the relationship between value chains and corporate performance in the case of firms forming a value chain with other companies with the means of an equity investment or a special business relationship. Design/methodology - Non-financial corporations listed from 2011 to 2017 on the securities market of South Korea are analyzed. The data used for analysis are found for transactions with the related party by year for all the corporations of non-financial industries in the securities market. Multiple analysis attempts are conducted including the relationship between the value chain and productivity, corporate value, risk-adjusted corporate value, and mediation effects of productivity. The empirical model employs sixteen variables including the value chain index which identifies its impact on various aspects of business performances. Findings - The results of this study clearly supports the phenomenon that corporate productivity and value are enhanced when the corporation expands its value chain established with domestic related firms and overseas companies. Such a positive effect is statistically significant even after the possible risk factors that accompany the expansion of value chain were considered, and productivity plays the role as a medicating variable in the effect of the value chain on the corporation values. Originality/value - The findings of this study confirms that domestic companies' expansion of their value chain centered on the related firms overseas that helped them in terms of the maximization of their productivity and corporate values. This study shows that Korean government's policy on expanding the corporate GVC can enhance the productivity and value of firms. The expansion of value chain and its impact on business performance has not been explored thoroughly, although it is getting more and more important in the global trade operation.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.427-434
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• 2001

In this paper, we consider the nonparametric Bayesian approach to the multiple comparisons problem for I Poisson populations using Dirichlet process priors. We describe Gibbs sampling algorithm for calculating posterior probabilities for the hypotheses and calculate posterior probabilities for the hypotheses using Markov chain Monte Carlo. Also we provide a numerical example to illustrate the developed numerical technique.

• 한국통신학회논문지
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• 제38A권12호
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• pp.1061-1068
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• 2013

본 논문에서는 ESPAR(Electronically Steerable Parasitic Array Radiator) 안테나를 이용한 $M{\times}M$ BS-MIMO(beam space multiple input multiple output) 시스템을 제안한다. 기존 MIMO 시스템은 전송 데이터 신호를 다수의 안테나에 맵핑시켜 전송하기 때문에 다수의 RF 체인이 필요한 문제점이 있다. 다수의 RF 체인은 하드웨어의 비용을 및 RF 회로의 전력 소모를 증가 시킨다. 또한, 휴대폰과 같이 공간적인 제약이 큰 모바일 장비에서 MIMO 시스템을 사용하기 어렵다. 이러한 문제를 해결하기 위해서 단일 RF 체인을 가지는 ESPAR 안테나를 사용하여 빔 공간에서 신호를 맵핑시키는 BS-MIMO 시스템이 제안되었다. 본 논문에서는 BS-MIMO 시스템 기법에 대해서 설명하고 이를 확장한 $M{\times}M$ BS-MIMO 전송 기법의 설계 및 성능을 분석한다. 컴퓨터 모의실험을 통한 성능 확인 결과 제안된 BS-MIMO 전송기법은 기존 MIMO 기법과 비교하여 거의 동일한 수신 BER 성능을 얻는다. 따라서 다수의 RF 체인을 가지는 기존 MIMO 시스템과 비교하여 BS-MIMO 시스템은 단일 RF 체인을 가지고 MIMO 전송이 가능하며, 이로 인해서 하드웨어 비용 및 RF 회로의 전력 소모를 획기적으로 줄일 것으로 예상된다.

• 한국치위생학회지
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• 제15권6호
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• pp.1063-1071
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• 2015

Objectives: The purpose of the study is to investigate the quantitative detection of periodontal pathogens before and after scaling by real-time polymerase chain reaction. Methods: Participants were voluntarily recruited at D university, and saliva samples were extracted before and after scaling. Multiple real-time polymerase chain reactions were used to analyze characteristics and the amount of nine kinds of periodontal pathogens; Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Campylobacter rectus, and Eikenella corrodens. Results: After scaling, most periodontal pathogens except Eikenella corrodens were significantly decreased in all subjects(p<0.05). In addition, the percentage of microorganisms associated with disease, the microorganism risk index of periodontitis and the prevalence of red complex, orange complex, and Aggregatibacter actinomycetemcomitans was also significantly reduced after scaling(p<0.05). Conclusions: Scaling decreased in the amount of major periodontal pathogens and periodontitis prevalence rate.

• 한국경영과학회지
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• 제31권2호
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• pp.113-127
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• 2006

We consider an integrated supply chain model in which multiple suppliers replenish items for a single buyer's demand. Also the buyer specifies a basic replenishment cycle and the suppliers replenish the items only at those time intervals. Namely, we propose a model to study and analyze the benefit by coordinating supply chain inventories through the basic replenishment cycle time. The objective of this model is to minimize the total relevant annual cost of the integrated inventory model. After developing proposed coordinated models, we suggest heuristics for searching the solutions of our models. Finally, numerical and computational experiments for each policy are carried out to evaluate the benefits of those models and the compensation policy is addressed to share the benefits.

• 대한가정학회지
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• 제38권2호
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• pp.27-40
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• 2000

The purpose of this study was to determine the consumption patterns of fast food chain stores according to their parents'social demographic factors in using fast food chain stores. The data of this research were composed of 599 college students in Taegu$.$Kyungbuk region. Obtained data were analyzed by X$^2$-test, t-test, oneway ANOVA and Duncan's multiple range test with SPSS PC+ program. The findings of this study are as follows; First, mother's academic background and father's occupations, family income level of the respondents were statistically significant in using fast food chain stores. Secondly, 19% of the respondents answered that they 'hardly'used fast food chain stoles, 65.4% of them 'sometimes', and 16% of them 'frequently'. Most of the respondents answered that they visit 'with their friends'. They prefer fast food because the flood is convenient to eat and the services are fast. The frequency of eating out was increased and their taste was apt to westernize.

• 전기전자학회논문지
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• 제3권1호
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• pp.50-56
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• 1999

본 논문은 정밀한 클락 지연을 발생하는 회로 기법을 제안하였다. 이 기법은 지연 체인을 다중 클락 주기에 록킹(Locking)시켜서 개별 지연단(Delay Stage)의 지연보다 작은 지연 해상도를 갖도록 하는 것이다. 이 기법으로 단위 셀이 750ps의 지연시간을 갖는 지연체인에서 DLL(Delay Locked Loop)을 이용하여 250ps의 지연간격을 갖는 지연 발생회로를 설계하였다. 제안한 회로는 지연체인이 클락 신호 주기의 3배에 록킹이 되도록 하였으며, 1.5um CMOS공정의 모의 실험을 통해 단위지연셀 지연시간의 1/3인 250ps의 지연간격을 발생함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.704-708
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• 2015

For the analysis of multiple-reaction intermediates for long-chain dicarboxylic acid biotransformation, simple and reproducible methods of extraction and derivatization were developed on the basis of gas chromatography with flame ionization detector (GC-FID) instead of mass spectrometry. In the derivatization step, change of the ratio of pyridine to MSTFA from 1:3 to 9:1 resulted in higher peak intensity (p = 0.021) and reproducibility (0.6%CV) when analyzing 32 g/l ricinoleic acid (RA). Extraction of RA and ω-hydroxyundec-9-enoic acid with water containing 100 mM Tween 80 showed 90.4-99.9% relative extraction efficiency and 2-7%CV compared with those with hydrophobic ethyl acetate. In conclusion, reduction of the pyridine content and change of the extraction solvent to water with Tween 80 provided compatible derivatization and extraction methods to GC-FID-based analysis of longchain carboxylic acids.

• Management Science and Financial Engineering
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• 제22권1호
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• pp.5-12
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• 2016

We consider a time-cost tradeoff problem with multiple milestones under a chain precedence graph. In the problem, some penalty occurs unless a milestone is completed before its appointed date. This can be avoided through compressing the processing time of the jobs with additional costs. We describe the compression cost as the convex or the concave function. The objective is to minimize the sum of the total penalty cost and the total compression cost. It has been known that the problems with the concave and the convex cost functions for the compression are NP-hard and polynomially solvable, respectively. Thus, we consider the special cases such that the cost functions or maximal compression amounts of each job are identical. When the cost functions are convex, we show that the problem with the identical costs functions can be solved in strongly polynomial time. When the cost functions are concave, we show that the problem remains NP-hard even if the cost functions are identical, and develop the strongly polynomial approach for the case with the identical maximal compression amounts.