• 한국수산과학회지
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• 제54권1호
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• pp.16-22
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• 2021

This study investigated the reduction in human norovirus (HNV) GII. 4 count in pacific oyster Crassostrea gigas using electron beam irradiation. Infectious HNV GII. 4 was detected using RT-qPCR (real time reverse transcription-quantitative polymerase chain reaction) with PMA (propidium monoazide)/sarkosyl. At electron beam doses 1, 5, 7, and 10 kGy, the count of HNV GII. 4 was 2.74, 2.37, 2.06, and 1.55 log copies/μL (control, 3.01 log copy/μL), respectively, confirming that as the irradiation dose increased, norovirus count reduced significantly (P<0.05). After PMA/sarkosyl treatment, the counts further reduced at the same irradiation dose, and 10 kGy showed significant differences between the non-treated and PMA/sarkosyl-treated samples (P<0.05). The Ed (decimal reduction dose of electron beam) value based on the first-order kinetic model was 7.33 kGy (R2=0.98). No significant difference was observed in the pH values of the control (6.2) and electron beam-irradiated samples at all doses (6.1). For sensory evaluation, the non-treated sample scored the highest in all categories (5.25-6.17), while the samples treated with 10 kGy showed the lowest score (4.67-5.33), although without statistical significance (P>0.05). Overall, our results suggest that 7 kGy electron beam is sufficient for the non-thermal sterilization of oysters without causing significant changes in quality.

• 경영과학
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• 제32권2호
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• pp.69-78
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• 2015

This paper considers a Bayesian Poisson model for multivariate count data using multiplicative rates. More specifically we compose the parameter for overall arrival rates by the product of two parameters, a common effect and an individual effect. The common effect is composed of autoregressive evolution of the parameter, which allows for analysis on seasonal effects on all multivariate time series. In addition, analysis on individual effects allows the researcher to differentiate the time series by whatevercharacterization of their choice. This type of model allows the researcher to specifically analyze two different forms of effects separately and produce a more robust result. We illustrate a simple MCMC generation combined with a Gibbs sampler step in estimating the posterior joint distribution of all parameters in the model. On the whole, the model presented in this study is an intuitive model which may handle complicated problems, and we highlight the properties and possible applications of the model with an example, analyzing real time series data involving customer arrivals to a large retail store.

• 지능정보연구
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• 제21권3호
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• pp.19-36
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• 2015

대표적 소셜미디어인 유튜브는 기존 폐쇄형 콘텐츠 서비스와는 다르게 개방형 콘텐츠 서비스로 이용자들의 참여와 공유를 통하여 많은 인기를 유지하고 있다. 콘텐츠 산업에서 중요한 위치를 차지하고 있는 유투브 상의 콘텐츠 확산 요인에 관한 기존의 연구들은 댓글 수 등과 같은 일반적 정보 특성 요인과 조회 수 간에 상관관계 등을 분석하는 것이 대부분이었다. 최근 네트워크 구조를 기반으로 한 연구들도 진행되었으나 대부분 콘텐츠를 이용하는 대상인 구독자나 지인 등을 중심으로 한 인적 관계 네트워크 구조 연구가 대부분이었다. 이에 본 연구에서는 실질적인 콘텐츠를 중심으로 한 네트워크 구조와 일반요인을 통합한 모델을 제시하고 확산요인을 분석하고자 한다. 이를 위해 통합 모델 인과관계 분석과 함께 21,307개의 유튜브 콘텐츠를 콘텐츠 기반 네트워크 구조로 분석하였다. 본 연구를 통해 기존에 알려진 일반적 요인과 네트워크 요인들이 모두 조회수에 영향을 주는 인과관계를 통계적으로 재검증하였으며 통합적으로는 등록자의 구독자 수, 경과시간, 매개 중심성, 댓글 수, 근접 중심성, 클러스터링 계수, 평균 평점 순으로 조회 수에 긍정적인 영향을 미치는 것으로 분석되었다. 하지만 네트워크 요인중 연결정도 중심성과 고유벡터 중심성은 부정적 영향을 주는 것으로 분석되었다. 본 연구를 통하여 유튜브 콘텐츠 확산에 대한 일반영향요인과 구조적인 현상을 함께 규명하였다. 본 연구는 기업들이 유튜브와 같은 콘텐츠 서비스를 통한 온라인 마케팅 활동 시 콘텐츠들의 구조적인 면을 고려할 수 있는 근거를 제공하였으며 음반산업의 수요예측이나 콘텐츠 제작 업체들의 원활한 서비스 제공을 위한 설명력있는 영향요인 및 모델이 될 수 있을 것이다.

• 한국도로학회논문집
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• 제20권2호
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• pp.119-126
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• 2018

PURPOSES : The purpose of this study is to develop a crash prediction model at signalized intersections, which can capture the randomness and uncertainty of traffic accident forecasting in order to provide more precise results. METHODS : The authors propose a random parameter (RP) approach to overcome the limitation of the Count model that cannot consider the heterogeneity of the assigned locations or road sections. For the model's development, 55 intersections located in the Daejeon metropolitan area were selected as the scope of the study, and panel data such as the number of crashes, traffic volume, and intersection geometry at each intersection were collected for the analysis. RESULTS : Based on the results of the RP negative binomial crash prediction model developed in this study, it was found that the independent variables such as the log form of average annual traffic volume, presence or absence of left-turn lanes on major roads, presence or absence of right-turn lanes on minor roads, and the number of crosswalks were statistically significant random parameters, and this showed that the variables have a heterogeneous influence on individual intersections. CONCLUSIONS : It was found that the RP model had a better fit to the data than the fixed parameters (FP) model since the RP model reflects the heterogeneity of the individual observations and captures the inconsistent and biased effects.

• 수산경영론집
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• 제43권2호
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• pp.41-49
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• 2012

This study aimed to estimate the economic value of the recreational fishing in the Jeonnam marine ranching area as a part of the total socioeconomic evaluation of the Jeonnam marine ranching program. A travel cost method was applied to the estimation of economic value of the recreational fishing in the Jeonnam marine ranching area and input variables included annual fishing trip days, average travel cost per trip, average catch amount, monthly income, marriage, age, and personal perception on the marine ranching program. In the analysis, due to its characteristic of count data, both poisson model and negative binomial model were used. Model results indicated that a negative binomial model was statistically more suitable than the poisson model as the overdispersion problem occurred in the poisson model. All signs of the estimated parameters were estimated as previous studies showed. Based on the results, the economic value per trip of the recreational fishing in the Jeonnam marine ranching area was estimated to be 145,000 won and the annual total economic value of the recreational fishing in the Jeonnam marine ranching area was analyzed to be 2,514,000 won. In addition, the change of total value by catch rate showed that the economic value could be increased by 180,900 won as the catch increased by one kilogram.

• 품질경영학회지
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• 제44권4호
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• pp.813-831
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• 2016

Purpose: The purpose of this study is to assess the service quality attributes of Korean airlines service for Chinese passengers and suggest revised model to count potential improvement. Methods: Using the Kano and Timko models based on survey questionnaire to classify the quality attributes and to calculate the customer satisfaction index for each service attributes. And the revised potential customers satisfaction index(R-PCSI) are used to access the improvement possibilities by Kano model's attributes. Results: The attributes by Kano model, the relative importance, and the priorities for improvement for 30 airline service quality characteristics are identified. The most important item for improvement is 'Loses and delays compensations service'. Conclusion: According to the PCSI calculation results, this paper can help for Korean Airlines to improve customer satisfaction for Chinese passengers. And R-PCSI model suggested by this paper can be used for other service quality analysis.

• 경영과정보연구
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• 제33권2호
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• pp.301-315
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• 2014

부산의 금정산은 도시 숲의 중요성이 부각되면서 시민들의 방문이 증가하고 있으며 이로 인해 생태계 보전을 위한 비용은 증가하고 있다. 도시 숲에 대한 보전과 이용의 양 측면을 고려하면서 지속가능한 환경자원으로서 금정산을 보호하기 위해서는 비용편익 관점에서 정책적 판단이 중요해지고 있다. 이와 관련하여 도시 숲의 편익을 화폐적 가치로 측정하여 환경정책의 경제적 효율성을 확보하자는 취지에서 금정산의 가치를 추정하였다. 본 연구에서는 금정산을 당일 방문한 20세 이상의 성인 남녀를 개인면접의 방식으로 설문을 조사하여 개인여행비용법(ITCM)으로 가치를 추정하였다. 종속변수인 여행횟수가 특성상 비음정수이므로 가산자료모형인 포아송 모형, 음이항 모형, 절단된 포아송 모형 및 절단된 음이항 모형을 사용하였다. 분석결과를 바탕으로 추정된 금정산의 1회 여행에서 얻은 경제적 가치는 60,669원이고, 총경제적 가치는 252,383원으로 계산되었다. 여행비용(COST)을 적용하였을 때 절단된 음이항 모형으로부터 관광수요모형을 추정하여 보니 예상했던 바와 같이 여행비용(COST)이 적을수록 여행 횟수가 증가하였고, 연령(AGE), 결혼여부(MAR), 그리고 경관 만족도(SATI)는 방문수요에 영향을 미치지 못하는 것으로 분석되었다.

• 산업공학
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• 제21권4호
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• pp.444-455
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• 2008

In the present manufacturing environment, the appropriate decision making strategy has a significance and it should count on the fast-changing demand of customers. This research derives the optimal levels of the decision variables affecting the inventory related performance in multi-stage supply chain by using simulation and genetic algorithm. Simulation model helps analyze the customer service level of the supply chain computationally and the genetic algorithm searches the optimal solutions by interaction with the simulation model. Our experiments show that the integration approach of the genetic algorithm with a simulation model is effective in finding the solutions that achieve predefined target service levels.

• Computers and Concrete
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• 제9권1호
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• pp.51-61
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• 2012

According to the results of three-point bending tests of rubberized concrete and plain concrete, the parameters such as total fracture energy ($G_F$), initial fracture energy ($G_f$), and tensile strength ($f_t$) are obtained for concrete material. Using ABAQUS software and a bilinear softening fictitious crack model, the crack propagation process was simulated and compared to the experimental results. It is found that the increase of AE hit count has a similar trend with the increase of energy dissipation in FEM simulation. For two types of concretes, both experimental results and numerical simulation indicate that the rubberized concrete has a better fracture resistance.

• 응용통계연구
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• 제25권5호
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• pp.865-875
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• 2012

In this study, we identify the variables that affect the number of crime and spatial correlation in the Seoul metropolitan area, in addition, we measure the relative risk on the incidence of crime by a Poisson regression model. We suggest a statistical methodology to make a risk map for crime based on relative risk instead of the total event of crime by region using the Geographic Information System. To demonstrate the use and advantages of this methodology, this study presents an analyses of the total crime count in 25 wards in the Seoul metropolitan area.