• 수산해양기술연구
• /
• 제55권3호
• /
• pp.264-272
• /
• 2019

The aim of this study is to analyze the relationship between international oil price as a fuel cost in overseas fisheries and skipjack tuna price as a part of main products in overseas fisheries using monthly time series data from 2008 to 2017. The study also tried to analyze the change of fishing profits by fuel cost. For a time series analysis, this study conducted both the unit-root test for stability of data and the Johansen cointegration test for long-term equilibrium relations among variables. In addition, it used not only the Granger causality test to examine interactions among variables, but also the Vector Auto Regressive (VAR) model to estimate statistical impacts among variables used in the model. Results of this study are as follows. First, each data on variables was not found to be stationary from the ADF unit-root test and long-term equilibrium relations among variables were not found from a Johansen cointegration test. Second, the Granger causality test showed that the international oil prices would directly cause changes in skipjack tuna prices. Third, the VAR model indicated that the posterior t-2 period change of international oil price would have an statistically significant effect on changes of skipjack tuna prices. Finally, fishing profits from skipjack would be decreased by 0.06% if the fuel cost increases by 1%.

• 한국가정과교육학회지
• /
• 제18권4호
• /
• pp.55-65
• /
• 2006

본 연구는 중학교 2학년에 재학 중인 남녀 청소년을 대상으로 하여 성별에 따른 인터넷 중독의 차이를 살펴보고 자아존중감, 부모와의 관계 친구관계가 청소년의 인터넷 중독에 미치는 영향을 파악하였다. 서울 시내의 중학교 2학년 학생 439명으로부터 수집된 자료를 분석한 결과를 요약하면 다음과 같다. 첫째, 성별에 따른 인터넷 중독의 차이를 분석한 결과, 남자 청소년이 여자 청소년에 비해 더 높은 수준의 인터넷 중독을 경험한 것으로 나타났다. 둘째, 남자 청소년의 인터넷 중독은 원만하지 못한 친구관계와 낮은 자아존중감에 의해 영향을 받는 것으로 나타났다. 여자 청소년의 경우에는 부모와의 관계와 친구관계가 인터넷 중독에 영향을 미치는 요인으로 나타났다. 본 연구의 결과는 청소년 개인의 긍정적 발달을 위한 가정과 교육의 기초 자료로 이용되고 청소년의 인터넷 중독 예방을 위한 교육 프로그램 및 청소년 프로그램 개발에 도움이 될 수 있다.

• 한국수자원학회논문집
• /
• 제45권1호
• /
• pp.39-52
• /
• 2012

유역내에서 발생하는 유출은 지표 유출과 지표하 유출이 있으며, 서로 상호작용 상태를 유지하게 된다. 일반적으로 지표와 지표하 둘 중 한 가지 알고리즘으로 해석이 힘든 유역에 대해 지표와 지표하 사이의 동적인 관계를 상세하게 모의해야 하는 경우 상호작용에 관한 요소를 고려하여야 한다. 동적인 상호작용 시스템의 구동에서는 시 공간적인 매개변수가 중요하며, 적절한 모의를 위해시 공간적인 매개변수는 시스템 상에서 지표와 지표하 항에 대한 복합적인 메카니즘으로 구성되어야 한다. 본 연구에서는 이러한 지표 및 지표하 유출의상호작용에 관한 알고리즘을 위해 2차원 확산파 방정식을 이용하여 지표 유출을 해석하고, Darcy의 법칙과 Dupuit-Forchheimer의 가정을 이용한 Boussinesq 방정식을 적용하여 포화상태의 지표하 유출의 알고리즘을 구성하였다. 커플링 방정식으로 공간에 대해서는 유한체적법을 사용하고, 시간에 대해서는 Crank-Nicolson 방법을 이용하였으며, 지표와 지표하 흐름의 상호작용에 대해서는 질량보존의 법칙에 기반하여 구성하였다. 이상의 과정을 통하여 지표 유출해석, 지표하 유출해석, 상호작용, 수치해석 부분의 4가지 주요 모듈을 만들었으며, 4가지 주요 모듈을 통합하여 복합유역의 지표 및 지표하 유출해석 모듈을 개발하였다.

• World Technopolis Review
• /
• 제3권1호
• /
• pp.39-54
• /
• 2014

Recently, investment to basic science has been increased and infrastructure of science and technology has been expanded in developed countries like U.S.A, UK and Japan to foster high-tech industries. Science and research parks are built and under operation to acquire national competitive power and to activate regional economy over the world today. It is argued that more synergy effects are generated when science and research parks are operated in cooperation with related organizations and facilities such as firms, universities, research institutes and governments than it is operated by one organization. The aim of this paper is to develop a governance model of science and research parks. One comprehensive model and three individual governance models were developed according to the structure and relations of industry-science/research park-supporting organization interactions. When governance model of science and research parks is established and properly managed, national development capacity would be greatly enhanced through the acceleration of technology transfer, industrial production rise and enhancement of efficiency in the area of R&D and supporting system etc. One of the key factors in building governance system for science and research parks is establishing a control tower that supervises governance system comprehensively and systematically.

• Asian Journal of Business Environment
• /
• 제11권4호
• /
• pp.17-29
• /
• 2021

Purpose: The aim of this study is to explore the dynamic linkage between conditional stock market volatility and macroeconomic uncertainty of Bangladesh. Research design, data, and methodology: This study uses monthly data covering the time period from January 2005 to December 2018. A comprehensive set of macroeconomic variables, namely industrial production index (IP), consumer price index (CPI), broad money supply (M2), 91-day treasury bill rate (TB), treasury bond yield (GB), exchange rate (EX), inflow of foreign remittance (RT) and stock market index of DSEX are used for analysis. Symmetric and asymmetric univariate GARCH family of models and multivariate VAR model, along with block exogeneity and impulse response functions, are implemented on conditional volatility series to discover the possible interactions and causal relations between macroeconomic forces and stock return. Results: The analysis of the study exhibits time-varying volatility and volatility persistence in all the variables of interest. Moreover, the asymmetric effect is found significant in the stock return and most of the growth series of macroeconomic fundamentals. Results from the multivariate VAR model indicate that only short-term interest rate significantly influence the stock market volatility, while conditional stock return volatility is significant in explaining the volatility of industrial production, inflation, and treasury bill rate. Conclusion: The findings suggest an increasing interdependence between the money market and equity market as well as the macroeconomic fundamentals of Bangladesh.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.764-769
• /
• 2007

This paper is studied the noise and vibration characteristics analysis of the three-phase induction AC motor of the electrical forklift. And we suggest the method which the reduction orders the noise and vibration to be the mechanical. In other to investigate these characteristics, we considered the mechanical characteristics, the electromagnetic effects, and these interactions. In mechanical, we studied the characteristic of the stator, the bearing supported condition of the rotor, and the sound radiation. In electronically, this paper is considered the harmonic effect which is related the magnetic motive force (mmf) with respect to the characteristic of the slot number of the rotor and the stator and the pole number of the motor. Finally we investigated the overall noise and vibration of the induction motor by relations between the electronically harmonic and the mechanical resonance of the stator. By the analysis of the generally three-phase induction motor, we suggest the design methodology to low noise and vibration.

• Journal of Information Technology Applications and Management
• /
• 제23권1호
• /
• pp.1-23
• /
• 2016

Social commerce (s-commerce) is a subset of e-commerce and uses social media for social interactions. Although s-commerce has been rapidly growing, disputes between some s-commerce firms and their consumers often occur over issues such as poor customer services, incorrect product information, and late refunds. In order for s-commerce to continuously grow, s-commerce firms need to build consumer-trust in their transaction process to minimize their consumers' uncertainty. The purpose of this study is to examine the relationships between the multidimensional trust (ability, integrity, benevolence) and the intention of continuous use of s-commerce. Moreover, this study presents antecedent factors needed for trust-building by applying the characteristics of s-commerce, and verifies the relations between the variables. We test and validate the research model and related hypotheses using structural equation modeling based on a survey done on 428 people who have previous experience with s-commerce. The result shows that trust has positive effect on the intention of continuous use, and verifies the necessity of the antecedent factors (social presence, assurance, informativeness, economic feasibility, and seller reputation) for trust-building. This study provides strategy for the continuous growth of s-commerce, and suggests theoretical implication that explains the relationship between the characteristics of s-commerce and consumers.

• 통상정보연구
• /
• 제10권1호
• /
• pp.51-72
• /
• 2008

Recently, CRM has been integrated with e-CRM based on information and technology and its introduction is increasing. In particular, as a-CRM effectively collects information of customers with low cost and consolidates relations with customers through interactions with them, it is easier to achieve the marketing goals of companies. This study examines theories of CRM and a-CRM, and discusses development plan for successful introduction of e-CRM based on case studies on its introductions. Political suggestions are presented as follows: First, the basic rule to manage customers in respect to e-CRM is customer-oriented management. For optimal customer management, various customer service channels that support customers in real world as well as online should be provided for the best e-CRM system. Second, of increasing online customers, important customers should be sorted out for which individualized services should be provided and if so, they can be faithful customers. It is believed to be a true development direction of e-CRM appropriate to current society. With introduction of e-CRM, values and needs of customers should be analysed through various sorts of communication and information activities, and segmental marketing activities should be developed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권3호
• /
• pp.792-812
• /
• 2022

Multi-agent systems often need to achieve the goal of learning more effectively for a task through coordination. Although the introduction of deep learning has addressed the state space problems, multi-agent learning remains infeasible because of the joint action spaces. Large-scale joint action spaces can be sparse according to implicit or explicit coordination structure, which can ensure reasonable coordination action through the coordination structure. In general, the multi-agent system is dynamic, which makes the relations among agents and the coordination structure are dynamic. Therefore, the explicit coordination structure can better represent the coordinative relationship among agents and achieve better coordination between agents. Inspired by the maximization of social group utility, we dynamically construct a factor graph as an explicit coordination structure to express the coordinative relationship according to the utility among agents and estimate the joint action values based on the local utility transfer among factor graphs. We present the application of such techniques in the scenario of multiple intelligent vehicle systems, where state space and action space are a problem and have too many interactions among agents. The results on the multiple intelligent vehicle systems demonstrate the efficiency and effectiveness of our proposed methods.

• 대한교통학회지
• /
• 제10권3호
• /
• pp.7-20
• /
• 1992

The common cycle time for the linded signals is usually determined for the critical intersecion, just because the cpacity of a signalized intersection depends on the cycle time. This may not be optimal since the interactions between the flow and the spatial structure of the route or the area are disregarded in this case. It is common to separate the total delay incurred at signals into two parts, a deterministic or uniform delay and a stochastic or random delay. The deterministic delays and the stochastic delays on the artery particularly related to signal cycle time. For this purpose a microscopic simulation technique is used to evaluate deterministic delays, and a macroscopic simulation technique based on the principles of Markov chains is used to evaluate stochastic delays with over flow queue. As a result of investigating the relations between deterministic delays and cycle time in the various circumstances of spacing of signals and traffic volume. As for stochastic delays the resalts of comparisons of the macroscopic simulation and Newell's approximation with the microscopic simulation indicate that the former is valid for the degree of saturation less than 0.95 and the latter is for that above 0.95. Newell's argument that the total stochastic delay on an arterial is dominated by that at or caused by critical intersection is certified by the simulation experiments. The comprehensive analyses of the values of optimal cycle time with various conditions lead to a model. The cycle time determined by this model shows to be approximately 70% of that calculated by Webster's.