• 제목/요약/키워드: 모형효율

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The Study of Hydraulic Channel Routing Model Considering Tide Influence on the Downstream of the Nakdong River (조위를 고려한 낙동강 하류부 수리학적 홍수추적 모형의 연구)

  • Lee, Eul-Rae;Kim, Jong-Rae;Shin, Cheol-Kyun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.1006-1010
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    • 2005
  • 본 연구는 1차원 부정류 해석모형인 FLDWAV 모형을 이용하여 댐방류 또는 상류지점의 지류유입유량과 하류단의 조위에 따른 영향이 낙동강 하류 홍수위에 미치는 영향을 해석하고, 이를 GUI 시스템과의 연계를 통한 효율적인 홍수관리시스템을 구축하는데 있다. 또한 수리학적 모형수행을 위한 입력자료가 될 수 있는 수문학적 모형과의 연계방법을 제시하였으며 예측조위와 하구둑 방류량을 고려한 합리적인 하류경계조건을 지정하기 위해 회귀방정식에 의한 하류부 예측조위산정방법을 제시하였다. 본 연구에서는 적포교 수위관측소를 기점으로 하여 낙동강 하구둑까지 110km를 대상구간으로 설정하였다. 상류경계조건으로는 적포교지점의 유입량과 남강, 밀양강, 양산천 등의 지류유입량 등을 현재 한국수자원공사에서 적용하고 있는 KOWACO 홍수분석모형에 의해서 산정하였다. 또한 하류경계조건은 하구둑 내수위의 실측자료를 이용하였으며 향후 예측을 위한 적용성을 위해서 하구둑의 유입량과 예측조위조건의 상관성을 이용하여 회귀식을 산정하였다. 또한 해석결과의 효율적인 도시를 위해서 홍수추적 모형과 연계한 GUI 시스템을 구축하였다. 과거 발생한 홍수사상에 대해서 적용한 결과 실측치와 관측치가 유사한 수위 거동을 나타내고 있었다. 본 연구의 결과를 이용하여 다른 수계에서도 홍수예경보시스템의 구축을 위한 수리학적 모형과 수문학적 모형의 연계를 통한 좀더 신뢰성있고 정확한 해석결과를 제시할 수 있을것으로 판단된다.

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The Comparative Study for ENHPP Software Reliability Growth Model based on Modified Coverage Function (변형 커버리지 함수를 고려한 ENHPP 소프트웨어 신뢰성장 모형에 관한 비교 연구)

  • Kim, Hee-Cheul;Kim, Pyong-Koo
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.6
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    • pp.89-96
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    • 2007
  • Finite failure NHPP models presented in the literature exhibit either constant. monotonic increasing or monotonic decreasing failure occurrence rates per fault. Accurate predictions of software release times. and estimation of the reliability and availability of a software product require quality of a critical element of the software testing process : test coverage. This model called Enhanced non-homogeneous Poission process(ENHPP). In this paper, exponential coverage and S-type model was reviewed, proposes modified(the superosition and mixture) model, which make out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method. model selection based on SSE statistics for the sake of efficient model, was employed.

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Three-Stage Strati ed Randomize Response Model (3단계 층화확률화응답모형)

  • Kim, Jong-Min;Chae, Seong-S.
    • The Korean Journal of Applied Statistics
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    • v.23 no.3
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    • pp.533-543
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    • 2010
  • Asking sensitive questions by a direct survey method causes non-response bias and response bias. Non-response bias arises from interviewees refusal to respond and response bias arises from giving incorrect responses. To rectify these biases, Warner (1965) introduced a randomized response model which is an alternative survey method for socially undesirable or incriminating behavior questions. The randomized response model is a procedure for collecting the information on sensitive characteristics without exposing the identity of the respondent. Many survey researchers have proposed diverse variants of the Warner randomized response model and applied their model to collect the information of sensitive questions. Using an optimal allocation, we proposed three-stage stratified randomized response technique which is an extension of the Kim and Elam (2005) two-stage stratified randomized response technique. In this study, we showed that the estimator based on the proposed response model is more efficient than Kim and Elam (2005). But by adding one more survey step to the Kim and Elam (2005), our proposed model may have relatively less privacy protection compared to the Kim and Elam (2005) model.

A Comparative Study of the Relationship between Port Effeciency and Ownership Structure (항만 소유구조에 따른 효율성 모형 비교연구)

  • Hwang, Jin-Soo;Jorn, Hong-Suk;Kan, Sung-Chan
    • The Korean Journal of Applied Statistics
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    • v.22 no.6
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    • pp.1167-1176
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    • 2009
  • Few studies have investigated the quantitative relationship between port ownership structure and port efficiency with mixed results. This paper therefore contributes to the empirical literature by investigating the impact of port privatization on port efficiency using sample data drawn from the world's major ports. Moreover, this study applies the Bayesian approach to estimate the impact of port ownership on port efficiency. We fit Bayesian stochastic frontier model which is introduced by Griffin and Steel (2007) by WinBUGS. World's 25 main ports data are used for analysis. Based on MCMC sampling, we estimate parameters of the model and efficiency index of each ports. Moreover, we add estimates from package Frontier 4.1c in order to compare them with Bayesian results.

Efficient Bayesian Inference on Asymmetric Jump-Diffusion Models (비대칭적 점프확산 모형의 효율적인 베이지안 추론)

  • Park, Taeyoung;Lee, Youngeun
    • The Korean Journal of Applied Statistics
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    • v.27 no.6
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    • pp.959-973
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    • 2014
  • Asset pricing models that account for asymmetric volatility in asset prices have been recently proposed. This article presents an efficient Bayesian method to analyze asset-pricing models. The method is developed by devising a partially collapsed Gibbs sampler that capitalizes on the functional incompatibility of conditional distributions without complicating the updates of model components. The proposed method is illustrated using simulated data and applied to daily S&P 500 data observed from September 1980 to August 2014.

A Study on the Asia Container Ports Clustering Using Hierarchical Clustering(Single, Complete, Average, Centroid Linkages) Methods with Empirical Verification of Clustering Using the Silhouette Method and the Second Stage(Type II) Cross-Efficiency Matrix Clustering Model (계층적 군집분석(최단, 최장, 평균, 중앙연결)방법에 의한 아시아 컨테이너 항만의 클러스터링 측정 및 실루엣방법과 2단계(Type II) 교차효율성 메트릭스 군집모형을 이용한 실증적 검증에 관한 연구)

  • Park, Ro-Kyung
    • Journal of Korea Port Economic Association
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    • v.37 no.1
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    • pp.31-70
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    • 2021
  • The purpose of this paper is to measure the clustering change and analyze empirical results, and choose the clustering ports for Busan, Incheon, and Gwangyang ports by using Hierarchical clustering(single, complete, average, and centroid), Silhouette, and 2SCE[the Second Stage(Type II) cross-efficiency] matrix clustering models on Asian container ports over the period 2009-2018. The models have chosen number of cranes, depth, birth length, and total area as inputs and container TEU as output. The main empirical results are as follows. First, ranking order according to the efficiency increasing ratio during the 10 years analysis shows Silhouette(0.4052 up), Hierarchical clustering(0.3097 up), and 2SCE(0.1057 up). Second, according to empirical verification of the Silhouette and 2SCE models, 3 Korean ports should be clustered with ports like Busan Port[ Dubai, Hong Kong, and Tanjung Priok], and Incheon Port and Gwangyang Port are required to cluster with most ports. Third, in terms of the ASEAN, it would be good to cluster like Busan (Singapore), Incheon Port (Tanjung Priok, Tanjung Perak, Manila, Tanjung Pelpas, Leam Chanbang, and Bangkok), and Gwangyang Port(Tanjung Priok, Tanjung Perak, Port Kang, Tanjung Pelpas, Leam Chanbang, and Bangkok). Third, Wilcoxon's signed-ranks test of models shows that all P values are significant at an average level of 0.852. It means that the average efficiency figures and ranking orders of the models are matched each other. The policy implication is that port policy makers and port operation managers should select benchmarking ports by introducing the models used in this study into the clustering of ports, compare and analyze the port development and operation plans of their ports, and introduce and implement the parts which required benchmarking quickly.

A Study on Discrimination Evaluation of DEA Models (DEA 모형의 변별력 평가에 관한 연구)

  • Park, Man Hee
    • The Journal of the Korea Contents Association
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    • v.17 no.1
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    • pp.201-212
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    • 2017
  • This study presented the new evaluation index which can evaluate the discrimination of DEA models. To evaluate the discrimination of DEA models, data were analyzed using importance index as suggested in previous study and the coefficient of variation as suggested in this study for the discrimination evaluation. This study selected the CCR-DEA, BCC-DEA, entropy, bootstrap, super efficiency, and cross efficiency DEA model for the discrimination evaluation and accomplished empirical analysis. In order to grasp the rank correlation of the models, this study implemented the rank correlation analysis between the efficiency of CCR model and BCC model and entropy, bootstrap, super efficiency, and efficiency of the cross efficiency model. The obtained results of this study are as follows. First, the discrimination rank of models using the importance index and the coefficient of variation was shown to be identical. Therefore, the coefficient of variation can be used the discrimination evaluation index of DEA model. Second, the discrimination of the super efficiency model was found to be the highest rank among 4 models according to the analysis of this present study. Third, the highest rank correlation with CCR model was the super efficiency model. In addition, the super efficiency model was found to be the highest rank correlation with BCC model.

Trend in Fuzzy Regression Model

  • 최승회;김해경;정은경
    • Proceedings of the Korean Statistical Society Conference
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    • 2004.11a
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    • pp.73-77
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    • 2004
  • 종속변수와 독립변수 사이의 통계적인 관계를 설명하기 위해 사용되는 회귀모형을 분석하는 방법을 회귀분석이라 한다. 독립변수와 종속변수가 퍼지수인 퍼지회귀모형을 추정하기 위해 최소전대편차추정량을 제시하고. 예제를 이용하여 퍼지최소절대편차회귀모형과 퍼지최소자 승회귀모형의 효율성을 평가한다.

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Analysis on the Relative Efficiency based on Data Envelopment Analysis for Colleges in South Korea - Focused on Evaluation of Basic Competency in College - (DEA분석을 기반으로 하는 한국 전문대학의 상대적 효율성 분석 -대학기본역량진단을 중심으로-)

  • Kim, Do-Jin;Lee, Yong-Gyoo
    • The Journal of the Korea Contents Association
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    • v.19 no.2
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    • pp.491-507
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    • 2019
  • The result of this study was to measure the relative efficiency of 133 colleges in south korea and to investigate the differences in the results of college basic competency evaluation. As a result of the study showed that the average difference of efficiency according to the background variables was no significant according to the scale, location, and college evaluation. but differences in the type of establishment were found to vary significantly in S.E model. In addition, it was analyzed that the efficiency of the college with limited funding for the efficiency distribution is highly distributed, which indicates that it is necessary to continuously improve the existing university methods and to assess whether they are being managed effectively. Finally, the limitations of this study are that it used only quantitative data and that additional indicators could result in different outcomes from the results of this study.

A Study on the Efficiency Analysis for the Domestic Container Terminals Considering Carbon Dioxide Emissions (이산화탄소 배출량을 고려한 국내 컨테이너터미널 효율성 분석)

  • Min-Seop Sim;Yul-Seong Kim
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.11a
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    • pp.68-69
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    • 2023
  • Recently, decarbonization has been emphasized worldwide to cope with climate change, and carbon neutrality by 2050 has emerged as a global agenda. The domestic port authorities have been participating in the global agenda in line with the government regulations. Since 2010, when decarbonization has been regarded as an important assignment in ports, container terminal efficiency considering undesirable outputs such as Carbon dioxide has been analyzed. However, most previous studies measured carbon dioxide emissions according to the Tier 1 and it is a first time to analyze container terminal efficiency based on the Tier 3 presented in the IPCC guidelines. 17 domestic container terminal operators were considered as decision making units and DEA-SBM Model was used. Subsequently, Undesirable outputs model was conducted to calculate the environmental efficiency.

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