OECD국가들의 수출성과에 관한 동태적 분석

조상섭,서청석,강신원 한국무역학회 2009 貿易學會誌 Vol.34 No.5

The change in dynamic structure and its long-term trend in terms of the export performance of 24 OECD countries from 1995-2004 is examined. To analyze the export structure, we first apply an entropy index to export performance to measure the total export concentration index of the 24 OECD countries, and then decompose the total export concentration index into the concentration degree between countries, and the product specialization degree within each. Then, using the decomposed related entropy index, the transition probability of degree of change and possibility of variation in the two entropy indices is calculated according to the conditional stochastic kernel function estimation on the basis of a stochastic difference equation and the Markov Chain analysis. The outcome of the analysis is outlined as follows. First, on average, regarding the export structure of the 24 OECD countries, the export concentration degree for 2004 was found to be lower than that for 1995, and the export product specialization degree was found to have increased. Compared with the USA and Japan, among other advanced countries, Korea weakened its export concentration in the OECD territory and strove to increase the diversity of its export products, thus changing its export structure in this region. Second, as regards the trend in the export concentration index, groups with a high export concentration showed a more unstable export structure; in the case of the between index of countries with a high export concentration degree in the OECD territory, the probability of transition, which shows the continuity of the current state, was found to be lower than the within index. Thus, OECD countries with a high total export entropy index are forecast to develop an export structure where export concentration and product specialization in the OECD region are bolstered.

잠재전이분석에서 종단측정동일성 검증을 위한 적합도 지수 수행력 탐색: 모의실험 연구

김재욱,손원숙 한국교육평가학회 2023 교육평가연구 Vol.36 No.3

잠재전이분석(Latent Transition analysis, LTA)에서 종단측정동일성(Longitudinal Measurement Invariance, LMI) 가정은 전이확률에 대한 해석을 간명하게 해주고, 모형 식별에 도움을 주며, 모수 추정의 편파를 줄여주는 등 개념적이고 통계적인 측면에서 이점을 가진다. 따라서 LTA에서 LMI 가정을 위한 동일성 검증이 필요하나, 이에 대한 인식과 실제적 방법론에 대한 논의가 부족했던 것이 사실이다. 이에 본 연구는 다양한 LMI 유형 중 구조동일성 수준에 초점을 맞춰 연구자들이 LTA에서 LMI 검증을 하는데 필요한 적합도 지수의 수행력 분석을 주요 연구문제로 다루고자 한다. 이를 위해 몬테카를로 시뮬레이션 방법에 따라 모의실험 연구를 설계하고 다양한 모의조건에서 LMI 검증 기준으로 흔히 활용되는 네 가지 적합도 지수의 수행력을 탐색하고 비교했다. 연구 결과 첫째, 구조동일성 모형 검증을 위한 적합도 지수의 수행력은 완전동일 및 부분동일 조건에 비해 비동일 조건에서 낮은 양상을 보였다. 둘째, 비동일 조건 중에서도 표본크기가 작고 탐지해야 하는 구조비동일성 정도가 작을 때 적합도 지수의 검증 수행력이 좋지 못했다. 셋째, 적합도 지수별로 수행력의 차이가 확인되었다. 마지막으로 본 연구를 논의하고 추후 연구를 위한 제언을 추가하였다.

실시간 IoT 데이터를 활용한 고객 관계 관리 방안에 관한 연구

배지원(Ji Won Bae),백동현(Dong Hyun Baek) 한국산업경영시스템학회 2019 한국산업경영시스템학회지 Vol.42 No.2

As information technology advances, the penetration of smart devices connected to the Internet, such as smart phone and tablet PC, has rapidly expanded, and as sensor prices have fallen the Internet of Things has begun to be introduced in the industry. Today s industry is rapidly changing and evolving, requiring companies to respond to the new paradigm of business. In this situation, companies need to actively manage and maintain customer relationships in order to acquire loyal customers who bring them a high return. The purpose of this study is to suggest a method to manage customer relationship using real time IoT data including IoT product usage data, customer characteristics and transaction data. This study proposes a method of segmenting customers through RFM analysis and transition index analysis. In addition, a real-time monitoring through control charts is used to identify abnormalities in product use and suggest ways of differentiating marketing for each group. In the study, 44 samples were classified as 9 churn customers, 10 potential customers, and 25 active customers. This study suggested ways to induce active customers by providing after-sales benefit for product reuse to a group of churn customers and to promote the advantages or necessity of using the product by setting the goal of increasing the frequency of use to a group of potential customers. Finally, since the active customer group is a loyal customer, this study proposed an one-on-one marketing to improve product satisfaction.

협착된 경동맥 내부 난류 천이 유동 직접수치모사를 통한 벽면전단응력 분석

김동민(Dongmin Kim),황진율(Jinyul Hwang),민두재(Too-Jae Min),조원민(Won-Min Jo) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

Blood flow in carotid arteries becomes unstable when stenosis is severe. The stenosed carotid artery induces the onset of turbulence in the post-stenotic region, which may significantly damage the endothelial cells. Here, we conduct a direct numerical simulation in a stenosed carotid artery to explore the transitional flow in the post-stenotic region. The pulsatile boundary condition is applied at the inlet of the stenosed carotid artery. The results demonstrate that transitional behavior happens between the acceleration and deceleration phases. It is shown that negative wall-shear stress (WSS) frequently occurs in this section. To quantify this behavior, we examine the probability density function of the WSS event. We further analyze the relationship between the negative WSS and the oscillatory shear stress index.

협착된 경동맥 내부 난류 천이 유동 직접수치모사를 통한 벽면전단응력 분석

김동민(Dongmin Kim),황진율(Jinyul Hwang),민두재(Too-Jae Min),조원민(Won-Min Jo) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

Blood flow in carotid arteries becomes unstable when stenosis is severe. The stenosed carotid artery induces the onset of turbulence in the post-stenotic region, which may significantly damage the endothelial cells. Here, we conduct a direct numerical simulation in a stenosed carotid artery to explore the transitional flow in the post-stenotic region. The pulsatile boundary condition is applied at the inlet of the stenosed carotid artery. The results demonstrate that transitional behavior happens between the acceleration and deceleration phases. It is shown that negative wall-shear stress (WSS) frequently occurs in this section. To quantify this behavior, we examine the probability density function of the WSS event. We further analyze the relationship between the negative WSS and the oscillatory shear stress index.

장애인을 위한 수요응답형 교통서비스의 효율성과 생산성 변화 분석

안성관,곽춘종 한국산업경제학회 2022 산업경제연구 Vol.35 No.6

The demand for Demand-Responsive Transit (DRT) services has increased for persons with disabilities and/or elderly people. Despite the importance and uniqueness of the DRT services, little work has been done for this area. The main objective of this paper is to evaluate the operating efficiencies and productivity changes of DRT services. The results indicate that the variations of the efficiency scores are getting smaller among DRT operators over several years, while those of input and output variables become bigger. Another interesting finding is that DRT service providers achieved increases in productivity by improvements in efficiency, not by technological progress. 장애인이나 노년층을 위한 수요응답형 교통서비스에 대한 수요는 꾸준히 증가해왔다. 수요응답형 교통서비스의 중요성과 고유한 특성에도 불구하고, 이 분야에 대한연구는 많지 않다. 본 논문의 목적은 국내 수요응답형 교통서비스의 운영 효율성과 생산성 변화를 평가하는 것이다. 연구 결과는 투입 변수와 산출 변수의 변동폭이 분석 기간에 걸쳐 점차 증가하는 반면, 수요응답형 교통서비스 운영자의 효율성 변동 폭은 분석 기간에 걸쳐 점차 줄어듬을 보여준다. 또 다른 흥미로운 점은 해당 분석 기간 동안 국내 수요응답형 교통서비스 운영자들의 생산성이 기술적인 진보보다는 효율성 증가에 의해 향상되었다는 것이다.

OECD국가들의 수출성과에 관한 동태적 분석

조상섭(Cho Sang Sup),서청석(Suh Chung-Suk),강신원(Kang Shin-Won) 한국무역학회 2009 貿易學會誌 Vol.34 No.5