Rationalization in Korea container terminal using DEA cross-efficiency and cluster analysis

Kim Sungki,Kim Chanho,Kim Sangyoul,Choi Sanggyun 한국해운물류학회 2022 The Asian journal of shipping and Logistics Vol.38 No.2

Ports and container terminals today are interchanges for maritime and land transport as well as important facilities that serve as communication channels for nations, regional economies, and forelands. They also act as suppliers providing cargo handling and international logistics services at the national level. Traditionally, the port industry was less competitive than other industries. However, competition among terminals is intensifying due to recent environmental changes, and the excessive competition between Korean container terminals has produced negative effects. Therefore, it is necessary to establish terminal rationalization plans to resolve excessive competition among container terminals at the national level. This study examined the direction for terminal rationalization at the national level to alleviate excessive competition among container terminals based on the theory of supply base rationalization. Data envelopment analysis (DEA) cross-efficiency and cluster analysis were combined to provide rationalization plans based on efficiency measurement. This study is significant as it presents a strategic analytical tool to establish terminal rationalization plans at the national level and also proves its applicability. © 2022 The Authors. Production and hosting by Elsevier B.V. on behalf of The Korean Association of Shipping and Logistics, Inc. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). CC_BY_NC_ND_4.0

An Analysis of Science Teachers’ Stages of Concern and Levels of Use on Descriptive Assessment

Kim, Sungki,Paik, Seounghey Korean Chemical Society 2016 대한화학회지 Vol.60 No.5

The goal of this study was to examine the current status of science teachers’ stage of concern (SOC) and level of use (LoU) on descriptive assessment and determine the relationship between SoC and LoU. To achieve this, concerns-based adoption model (CBAM) was used, and a survey was conducted on 138 science teachers. The data from this study were analyzed by frequency analysis, percentile analysis based on CBAM, χ² test, and Spearman correlation analysis. SoC and LoU of the science teachers observed in this study are as follows. First, the science teachers’ overall SoC for the descriptive assessment was low and showed a typical pattern of the initial stage when the program was introduced. Second, LoU analysis on descriptive assessment showed that the “mechanical Use” (N=49, 35.5%) or “routine” (N=48, 34.8%) accounted for the majority. Third, the Spearman correlation between SoC and LoU on descriptive assessment was .299(p<.01). This suggests that teachers’ SoC needs to be increased in order to promote higher LoU on descriptive assessment, which requires new alternative measures.

THE EFFECTS OF MESH STYLE ON THE FINITE ELEMENT ANALYSIS FOR ARTIFICIAL HIP JOINT

Sungki Kim,Junseok Kim 한국산업응용수학회 2011 한국산업응용수학회 학술대회 논문집 Vol.6 No.1

In this paper, a good quality mesh generation for the finite element method is investigated for artificial hip joint simulations. In general, bad meshes with a large aspect ratio or mixed elements can give rise to excessively long computational running times and extremely high errors. Typically, hexahedral elements outperform tetrahedral elements during three-dimensional contact analysis using the finite element method. Therefore, it is essential to mesh biologic structures with hexahedral elements. Four meshing schemes for the finite element analysis of an artificial hip joint are presented and compared: (1) tetrahedral elements, (2) wedge and hexahedral elements, (3) open cubic box hexahedral elements, and (4) proposed hexahedral elements. The proposed meshing scheme is to partition a part before seeding so that we have a high quality three-dimensional mesh which consists of only hexahedral elements. The von Mises stress distributions were obtained and analyzed. We also performed mesh refinement convergence tests for all four cases.

Effects of Revenue-Sharing Contracts on the Profits of Competing Manufacturers and a Retailer

Sungki Kim(김성기),Nina Shin(신니나),Sangwook Park(박상욱) 한국경영과학회 2018 한국경영과학회지 Vol.43 No.2

This study investigates the effect of revenue-sharing contracts in two competing manufacturers and one common retailer model under game theoretic settings. One manufacturer uses a revenue-sharing contract (RSC) and the competitor a wholesale price contract (WPC). We study whether the adoption of an RSC coordinates the supply chain of the RSC-adopting manufacturer and the retailer and how it affects two manufacturers’ profits under two game scenarios : two-stage and one-stage game. We analyze the effects of demand parameters which represent product characteristic, such as price sensitivity and product substitutability on supply chain members’ profits. We find that the RSC in the two-stage game does not coordinate the supply chain. Conversely, the RSC in the one-stage game coordinates the corresponding supply chain for some sets of demand parameters values, and that for others, the competing manufacturer experience greater profit increase than the RSC-adopting one.

NUMERICAL SIMULATION OF TURBULENT FLOW THROUGH A DENTAL HANDPIECE

Sungki Kim 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.4 No.2

A turbulent flow through a dental handpiece is numerically simulated using a commercial computational fluid dynamics software package. The dental high-speed handpiece is one of devices used in making holes, cutting, and polishing tooth structure in dentistry. The high-speed handpiece usually rotates at more than 400,000 rpm (rotation per minute). The simulation uses the standard κ-ε model and a multiple reference frame. We investigate the flow field inside handpiece device to find an optimal design of the structure to increase the torque.

An indentation method for evaluation of residual stress: ESTIMATION of stress-free indentation curve using stress-independent indentation parameters

Kim, Jong-hyoung,Choi, Sungki,Lee, Junsang,Ahn, Hee-Jun,Kim, Young-Cheon,Choi, Min-Jae,Kwon, Dongil Cambridge University Press (Materials Research Soc 2019 Journal of materials research Vol.34 No.7

<▼1><B>Abstract</B><P/></▼1><▼2><P>Residual stress is generally evaluated using indentation by comparing the indentation curves of stressed and stress-free states. Here, we suggest a new method that can evaluate surface residual stress without indentation testing on stress-free specimen using stress-independent indentation parameters and an analysis of indentation contact morphology for the stress-free state. We found that several indentation parameters are independent of the stress by Vickers indentation testing on various stress states. The indentation contact morphology can be represented by indentation parameters including stress-independent ones, and by applying the stress-independent parameters obtained from the stressed state to the indentation contact depth function, we can estimate an indentation curve for stress-free state. The estimated curve matches well with the experimental stress-free indentation curve, and it was also confirmed that the applied stress values evaluated by comparing the estimated curve with the stressed indentation curve agree well with the reference values obtained from strain gauge.</P></▼2>

Prerequisite Items of Spent Fuel Evaluation during Transportation and Interim Storage

Soyoung Kim,Yoonhee Lee,Sungki Lee,Yilsup Jung,Jinkyoung Kim,Sangjin Lee 한국방사성폐기물학회 2013 한국방사성폐기물학회 학술논문요약집 Vol.11 No.2

연합대학 설립‧운영의 법제화 방안

김성기(Sungki Kim),김병주(Byoungjoo Kim) 대한교육법학회 2023 敎育 法學 硏究 Vol.35 No.1

이 연구에서는 연합대학의 필요성과 개념, 형태, 사례 및 연합대학 설립‧운영을 법제화하기 위한 방안을 제시하였다. 대학별 강점분야를 연계한 대학간 협력체계가 필요하다. 지금까지는 단순히 학점교류에 머물러 있었다. 교육부는 2021년에 디지털 신기술 인재양성 혁신공유대학 기본계획을 발표하였다. 그러나 연합대학이 명시적으로 법적 근거를 갖추고 있지 못하다. 이에 이 연구에서는 연합대학의 법적 개념과 설립인가, 공유범위, 규약, 의사결정체제, 총장 등 교직원 구성, 경비 부담, 참여 및 탈퇴, 허용범위 등과 관련하여 법적 근거를 마련하고자 하였다. In this study, the necessity, concept, form, case, and method of legislating the establishment and operation of the union university were presented. A cooperative system between universities that links the strengths of each university is needed. So far, it has simply been limited to credit exchange. In 2021, the Ministry of Education announced the Basic Plan for Innovation Sharing University to Foster Digital New Technology Talents. However, the union university does not have an explicit legal basis. Therefore, in this study, we tried to establish a legal basis for the legal concept of the union university, authorization for establishment, scope of sharing, regulations, decision-making system, composition of faculty members such as the president, burden of expenses, participation and withdrawal, and scope of permissibility.

보행자 하지 보호를 위한 SUV차량의 최소인입량 및 Upper Leg 임팩터의 분석

민성기(Sungki Min),고은영(Eunyoung Ko),홍정화(Junghwa Hong),안이문(Leemoon Ahn),김동석(Dongseok Kim),김형일(Hyungil Kim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

There are many researches about design change of car in order to satisfy regulations of pedestrian protection like EEVC WG-17 in Europe. But these researches give insufficient understanding of impactors being used in the impact test because they attach importance to design change of car. So this study gave a description of impactor stiffness and moment through change about shape of impact object, impact position and impact angle. By using result, we suggested a method to estimate intrusion of car which required to satisfy the regulations of pedestrian protection.

뜨고 가라앉는 현상에 대한 과정적 관점 설명방식에 대한 교사들의 인식

김성기 ( Sungki Kim ),백성혜 ( Seoung-hye Paik ) 한국과학교육학회 2020 한국과학교육학회지 Vol.40 No.6

본 연구는 기존의 밀도라는 개념은 현상에 대한 원인자를 제공하는데 한계점이 있으며, 부력이라는 개념은 많은 오개념을 갖고 있고 정량적 계산을 이해하기 위해 지나치게 어려운 개념이 필요함에 문제를 제기하여 지레의 원리를 적용한 과정적 관점의 새로운 설명방식을 제안하였다. 새로운 설명방식은 중력이라는 근본원리와 과정적 관점이 드러나도록 지레라는 가시적 도구를 활용하여 제안되었다. 연구결과, 교사들은 많은 대안개념에 머물러 있었으며 밀도가 중력과 관련됨을 인식하는 교사는 절반이상 되지 않았다. 뿐만 아니라 이 현상을 물질적 관점으로 이해하면서 관점과 불일치하게 인식하였으나 수업처치 후 유의미한 개념 변화를 하였다(p<.000). 또한, 기존의 설명방식에 비해 원리와 과정적 관점을 잘 인식할 수 있다는 평가를 하였다. 이를 통해 지레의 원리를 도입한 과정적 과점의 설명방식에 대한 교육적 가치를 확인할 수 있었다. In this study, the existing concept of density has a limitation in providing the cause of phenomena, and the concept of buoyancy poses a problem because it has many misconceptions and requires an overly difficult concept to understand quantitative calculation, so we suggest an explaining method as process viewpoint introducing the principle of lever. The new method of explanation has been proposed using the lever as visual tool to reveal the gravity as the fundamental principle and process viewpoint. As a result, teachers stayed on many alternative concepts and less than half of the teachers were aware that density was related to gravity. In addition, they recognized it as matter viewpoints, but there is a meaningful conceptual change after intervention(p<.000). Also, they evaluated that the new method is better able to recognize the principle and process viewpoint than the existing description method. Through this, we can confirm the educational value of explaining method as process viewpoint introducing the principle of lever.