• Communications for Statistical Applications and Methods
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• 제25권1호
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• pp.15-27
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• 2018

Parametric method of flood frequency analysis involves fitting of a probability distribution to observed flood data. When record length at a given site is relatively shorter and hard to apply the asymptotic theory, an alternative distribution to the generalized extreme value (GEV) distribution is often used. In this study, we consider the beta-P distribution (BPD) as an alternative to the GEV and other well-known distributions for modeling extreme events of small or moderate samples as well as highly skewed or heavy tailed data. The L-moments ratio diagram shows that special cases of the BPD include the generalized logistic, three-parameter log-normal, and GEV distributions. To estimate the parameters in the distribution, the method of moments, L-moments, and maximum likelihood estimation methods are considered. A Monte-Carlo study is then conducted to compare these three estimation methods. Our result suggests that the L-moments estimator works better than the other estimators for this model of small or moderate samples. Two applications to the annual maximum stream flow of Colorado and the rainfall data from cloud seeding experiments in Southern Florida are reported to show the usefulness of the BPD for modeling hydrologic events. In these examples, BPD turns out to work better than $beta-{\kappa}$, Gumbel, and GEV distributions.

• 대한한의학회지
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• 제38권4호
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• pp.104-109
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• 2017

Objectives: Epicardial fat is true visceral fat that is known to be associated with metabolic syndrome, high abdominal fat, insulin resistance, coronary artery diseases, low coronary flow reserve and subclinical atherosclerosis. Dampness-Phlegm pattern is one of the pattern diagnosis of traditional Korean medicine. Previous studies showed that Dampness-Phlegm pattern is associated with hypertension, dyslipidemia, metabolic syndrome. This study is intended to find association between Dampness-Phlegm pattern and epicardial fat thickness. Methods: This study was a community-based single center trial. Ischemic stroke patients within 30 days after their ictus were enrolled. Epicardial fat thickness was measured using transthoracic echocardiography. Other measured and obtained variables are medical history, weight, height, body mass index, fasting blood glucose, cholesterol, triglycerol, high density lipoprotein, lipid and low density lipoprotein. Results: Three hundred sixty six were enlisted, and one hundred forty were diagnosed with the Dampness-Phlegm pattern. Dampness-Phlegm pattern group had significantly thicker epicardial fat. Binary logistic regression also showed statistically significant result. Conclusions: This study showed close association between epicardial fat and Dampness-Phlegm pattern. This result suggests a clue to standardization of pattern identification.

• Wind and Structures
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• 제7권1호
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• pp.29-40
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• 2004

This study has focused on aerodynamics for a wind-resistance design about the single and tandem box girder sections to realize a super-long span bridge in the near future. Three-dimensional static analysis of flows around the fundamental single and tandem box girder sections with fairing is carried out by means of the IBTD/FS finite element technique with LES turbulence model. As the results of the analysis, computations have verified aerodynamic characteristics of both sections by the histories of aerodynamic forces, the separation and reattachment flow patterns and the surface pressure distributions. The relationship between the section shapes and the aerodynamic characteristics is also investigated in both sections. And the mechanism about the generation of fluctuating aerodynamic forces is discussed.

• 산업경영시스템학회지
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• 제32권4호
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• pp.72-78
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• 2009

Reverse logistics is the process of planning and controlling the recovery flow of end of life products. Industry is increasingly being confronted with the need to solve several reverse logistics issues because of not only stringent environmental legislations but also economic reasons. Recently, thanks to the advent of emerging technologies, such as RFID, enhancing the productivity of reverse logistics operations has been highlighted. The application of RFID technology is going beyond forward logistics, which is the delivery of manufactured goods to consumers, and being expanded, though not frequently yet, to reverse logistics, which includes return, recovery, reuse, reproduction and disposal. However, it requires a deep insight for the research of reverse logistics and new environment. In this regard, we studied effectiveness by applying RFID middleware technology to reverse logistics.

• 한국항만경제학회지
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• 제18권2호
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• pp.91-108
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• 2002

The World has been rapidly changing into either technological aspects or perception of those who has utilised to the corresponding informational impact. Whatever areas we have actually been involved in are strongly connected with this evolution of informational technology in one way or another. Logistics is not a exception as well as trade. Two main routes in distribution channel such as commercial and physical flow of goods, have been operating in terms of I-business. In order to activate E-trade with E-commerce, E-logistics should be utilised and emphasized in more efficient and effective manner of doing job as a facilitator. So, in this paper, it studied the role of E-logistics to make E-trade better work as well as to look into present situations in E-commerce. Then, it was identified that some facilities as 3PL or shipping company have to adopt information in their business process with a view of valued add service providers. This means those who have implemented E-Logistics activities, should be more competitive in the market, only when they provide the value-added total logistics services.

• 한국산업융합학회 논문집
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• 제24권2_1호
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• pp.79-89
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• 2021

Poly(lactic acid) (PLA) is considered as one of the most promising bio-based polymers due to its high strength, high modulus, good processability, transparency after processing, and commercial availability. This study aimed to investigate the mechanical, thermal, and migration properties of poly(lactic acid)/zeolite (10 phr) composites prepared with various biocompatible plasticizers, such as triethyl citrate(TEC), tributyl citrate(TBC), and poly(ethylene glycol)(PEG400), through differential scanning calorimetry(DSC), thermo-gravimetric analysis(TGA) and standard tensile testing. The incorporation of PEG400 significantly increased the elongation at break, and DSC results showed that the addition of plasticizers drastically decreased the T_g of PLA/zeolite composites and improved the melt flow and processability. Besides, it was found from TGA results that PLA/zeolites composites plasticized by TEC and TBC were more easily to be thermally degraded than the composites plasticized by PEG400.

• 융합경영연구
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• 제6권1호
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• pp.25-30
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• 2018

Purpose - This paper mainly studied the role of the logistics legal system in promoting international transport logistics, building marine economy international cooperation demonstration zone and deepening the economic and financial cooperation etc between China and Korea. Research design, data, and methodology - The study conducted a survey on China and Korea's 2012-2017 years data. After empirically analyzing the data, we believe that cultural industry in Korea and China will maintain its growth momentum. Results - This study explored the way to establish an integrated logistics system between China and Korea to match the e-commerce certification system, online payment system and logistic distribution, thereby gradually promoting economic development and logistics integration in Asia. Conclusions- China-Korea FTA can encourage private flow to take on enterprises. In terms of improving logistics efficiency, reducing logistics costs and establishing a unified logistics industry standardization system. This will accelerate logistics industry integration in Northeast Asia, build a unified logistics management center in Northeast Asia, and promote a new model of integrated logistics cooperation in Northeast Asia. Therefore, it has a practical and reference significance.

• 대한교통학회지
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• 제29권3호
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• pp.73-82
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• 2011

최근 교통상황을 정확하게 관측할 수 있는 교통류 검지에 관한 기술개발과 더불어 개별차량 주행궤적을 이용한 교통안전도 평가기법에 대한 관심이 높아지고 있다. 본 연구에서는 개별차량의 주행궤적을 이용하여 다음시점(t+1) 의 후미추돌 확률을 산출하는 방법론을 제시하였다. 신뢰성 있는 예측 기법인 칼만 필터링(Kalman Filtering)을 이용하여 주행궤적을 예측하고, 예측된 시점에 대한 개별차량의 후미추돌 확률을 산출하였다. 안전도를 평가하는 확률모형을 수립하기 위해서 서해안 고속도로의 동영상 자료로부터 개별차량의 주행궤적을 추출하였다. 추출한 개별차량의 주행궤적 자료를 이항 로지스틱 회귀분석(Binary logistic regression)을 이용하여 차량의 차로변경 결정 확률 모형을 생성하였고, exponential decay function을 이용하여 surrogate safety measure(SSM)의 하나인 time-to-collision(TTC)기반의 추돌확률 모형을 생성하였다. 미시적 교통류 시뮬레이터인 VISSIM에서 추출한 개별차량의 주행궤적 데이터를 이용하여 제안된 방법론을 평가하였다. 본 연구의 결과는 교통류 감시, 제어 및 정보 시스템에 효과적으로 적용될 수 있으며, 나아가 교통사고 예방에 효율적인 대안이 될 수 있을 것으로 판단된다.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.45-52
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• 2021

The article proves the relevance of developing conceptual frameworks for managing the quality assurance of logistics activities in the context of socio-economic interaction of their participants. It is established that the fundamental difference of the logistic approach in management from traditional approaches is the allocation of a single management function of previously separated, disparate material flows, as well as economic, technological, information integration of chain links into a single system capable of effective management of these flows. It is substantiated that the functioning of the enterprise as a logistics system can be represented in the form of a triad of logistics components, namely: supply logistics, production logistics, sales logistics. Management of quality assurance processes of logistics activities in the context of socio-economic interaction of their participants is a functional component of the entire logistics system due to the quality of work and interaction of all participants in the implementation of certain activities. The quality of logistics activities will affect the level of economic potential, rationalization and optimization of all logistics flows. It is proved that the management of quality assurance processes of logistics activities in the context of socio-economic interaction of their participants involves the following main areas: the introduction of a quality system of logistics processes; development and implementation of the general strategy of quality improvement at the enterprise; internal integration; controlling. Management of quality assurance processes of logistics activities in the context of socio-economic interaction of its participants requires compliance with the following requirements: systematic and comprehensive management of all flow processes; coordination of criteria and indicators for assessing the effectiveness of the entire logistics system; dissemination of the use and application of information technology; ensuring partnerships and close interaction of all participants in sales networks.

• 한국전산유체공학회지
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• 제19권4호
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• pp.80-85
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• 2014

High-volume low-speed (HVLS) fans are one category of ceiling fan installed in large enclosings such as warehouses, large barns and health clubs in order to generate comfortable air circulation. As a rotary blade, aerodynamic performance of a HVLS fan is predominantly related to its airfoil(s), and the pitch and twist angles. This paper first, investigates the effects of airfoil on the performances of three different HVLS fans with NACA 5414, 6413 and 7415 airfoils. The fans have six untwisted blades with the diameter of 6 m and rotate at 60 RPM. The blades pitch angels are $12^{\circ}$, $12^{\circ}$ and $13^{\circ}$, respectively. The results are presented in the form of the aerodynamic forces and moments, volumetric flow rate and streamlines. Regarding the volumetric flow of air, the results show that the model with NACA 7415 has the best performance. Hence, two other HVLS fans with the same airfoil but, with four and five blades are studied in order to investigate the effects of number of blades. From the point of view of air circulation still the six-bladed fan is the best one; however, the five-bladed fan is more efficient in power consumption.