• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1479-1482
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• 2003

The shock absorber is a part having a direct influence on the ride comfort, stability and dynamic load prediction of a vehicle. Thus, a rationally modeled shock absorber should be required in the dynamic analysis of vehicles. This thesis presents a modified model, based on Worden's hyperbolic tangent function, in order to fit experimental data on the velocity-damping force of a shock absorber. The hyperbolic tangent function correctly indicates the characteristics of a shock absorber. and has the advantage of containing physical causality. To evaluate the method, comparative evaluations of the linear model. the 5th polynomial model and Worden's model were carried out. The function presented in this paper is not only simple but also makes it possible to estimate the function coefficients easily and visually. In addition, it has the advantage of containing physical causality. Lastly, it effectively models the damping force of a shock absorber.

• 전자공학회논문지A
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• 제30A권10호
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• pp.20-26
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• 1993

The base-collector capacitance of an npn bipolar transistor in bipolar or BiCMOS technology has significant influence on the switching performances, and comprises pnjunction component and MOS component. Both components have complicated dependences on the isolation oxide structure, epitaxial doping density, and bias voltage. Analytical/empirical formulas for both components are derived in this paper for a generic isolation structure as a function of epitaxial doping density and bias voltage based on some theoretical understanding and two-dimensional device simulations. These formulas are useful in estimating the effect of device isoation schemes on the switching speed of bipolar transistors.

• 지식경영연구
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• 제12권2호
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• pp.56-68
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• 2011

The rapid changes in business environments are also applicable to the delivery service field. Numerous companies are using smart phones in order to perform work of the delivery service field that is rapidly developing every year. Smart phones established ubiquitous work environments where access to the server of the head office is possible through telephones, scanners, and the internet anywhere and anytime. However, although smart appliances including smart phones have been diffused, empirical analysis of use of them in actual has not been attempted much. In this regard, current study empirically analyzes how connectivity and context-awareness function of smart phones based on the TAM(Technology Acceptance Model) influence the continuous intention to use through trust, usefulness, and ease of use. The results indicate that the connectivity and context-awareness function, which are natures of smart phones, had impacts on the ease of use and trust, but not on the usefulness. Based on these results, this study suggests implications and future research directions regarding the planning and realization of smart appliances.

• 한국정보시스템학회지:정보시스템연구
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• 제26권1호
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• pp.143-169
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• 2017

Purpose With the increase of the elderly population, the growth of its information system related market is increasing. However, empirical studies for the usage of elderly people's smartphones are still limited. This study aims to investigate the factors that affect the seniors' smartphone usage behaviors. Design/Methodology/Approach First, a preliminary study was conducted with targeting seniors who have visited Gwangju Senior Technology Center(GSTC) in order to understand the factors that affect the intention of utilizing smartphones. Next, based on the preliminary study results and literature reviews including the UTAUT model, performance expectancy, effort expectancy and social influence were considered for the major factors affecting the usage of elderly people's smartphones. Also, the moderate effects of personal innovativeness and usage function were discussed. A questionnaire survey of 181 seniors visiting GSTC was analyzed to empirically test the research model. Findings By the empirical tests, the performance expectancy and the effort expectancy of the seniors had significant impacts on their smartphone usage behavior. While the moderating effect of personal innovativeness was not significant, the moderating effect of the usage function was significant in the relationship between performance expectancy and the smartphone usage behavior. The results of this study are expected to provide guidelines to excavate the technical development and the niche market targeting the elderly people.

• 한국환경과학회지
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• 제29권11호
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• pp.1141-1151
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• 2020

The impact of sound speed variability in the sea is the very important on acoustic propagation for the underwater acoustic systems. Understanding of the temporal and spatial variability of ocean sound speed in the sea around the Ieodo were obtained using oceanographic data (temperature, salinity). from the Korea Oceanographic Data Center, collected by season for 17 years. The vertical distributions of sound speed are mainly related to seasonal variations and various current such as Chinese coastal water, Yellow Sea Cold Water (YSCW), Kuroshio source water. The standard deviations show that great variations of sound speed exist in the upper layer and observation station between 16 and 18. In order to quantitatively explain the reason for sound speed variations, Empirical Orthogonal Function (EOF) analysis was performed on sound speed data at the Line 316 covering 68 cruises between 2002 and 2018. Three main modes of EOFs respectively revealed 55, 29, and 5% the total variance of sound speed. The first mode of the EOFs was associated with influence of surface heating. The second EOFs pattern shows that contributions of YSCW and surface heating. The first and second modes had seasonal and inter-annul variations.

• 한국분무공학회지
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• 제14권3호
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• pp.122-130
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• 2009

Vegetable oil and its derivatives as an alternative diesel fuel have become more attractive recently because of its environmental benefits and the fact that they are made from renewable resources. Viscosity is the most significant property to affect the utilization of vegetable oil and its derivatives in the compression ignition engines. This paper presents the existing correlations for predicting the viscosity of vegetable oil and its derivatives for compression ignition engines. According to the parameter considered in the correlations, the empirical correlations can be divided into six groups: correlations as a function of temperature, of proportion, of composition, of temperature and composition, of temperature and proportion, and of fuel properties. Out of physical properties of fuel, there exist in the literature several parameters for giving the influence on kinematic viscosity such as density, specific gravity, the ratio of iodine value over the saponification value, higher heating value, flash point and pressure. The study for the verification of applicability of existing correlations to non-edible vegetable oil and its derivatives is required.

• Asia pacific journal of information systems
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• 제11권4호
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• pp.135-153
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• 2001

Internet business is transforming the current structure and way of shopping behaviors. As a frontier area of internet business, internet shopping mall industry is influenced by this trend. In this shopping situation, shopping objects and information on the object are separated, which makes consumers to decide on the contents and marketing function offered by the shopping mall. This study proposes an integrated model including the influencing factors on customer royalty in Internet shopping environments. Eight hypotheses are proposed based on previous research in Internet marketing and information systems. The results are quite supporting the model and hypotheses. The contents structure, marketing activities, and customer satisfaction in the internet shopping environment influence shopping experience, next purchases and reference to other people. The proposed model and empirical results would contribute to setting up strategy of Internet shopping mall industry, and also to future research in information systems and Internet marketing.

• Journal of Information Processing Systems
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• 제20권1호
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• pp.76-84
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• 2024

This study constructed a VAR model with cotton futures and spot price data from April 30, 2009 to November 16, 2022, for empirical analysis utilizing the Granger causality test to analyze the dynamic relationship between cotton futures and spot market prices in China. The impulse response function and variance decomposition analysis showed that the cotton spot prices at flowering have a causal relationship with each other; in terms of mutual influence and impact, futures prices are higher than spot prices. Finally, it proposed countermeasures and suggestions from the perspective of establishing a standardized cotton spot market, improving the laws and regulations of the cotton futures market and trading system, and optimizing the structure of investment subjects.

• 유통과학연구
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• 제13권6호
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• pp.71-78
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• 2015

Purpose - This study attempts to analyze whether or not there are characteristics among the top management of companies that promote corporate performance at venture companies. It investigates the characteristics of the human and social capital that are inherent in top management at a venture company and conducts an empirical analysis of hypotheses examining if these characteristics will affect utilization of the governmental R&D support system as well as affect the firm's initial success. Research design, data, and methodology - This study conducted theoretical and empirical research together to accomplish the goal of the study. The pilot study researched human capital and social capital as the independent variables; the governmental R&D support system as the parameter; and, the initial success as the dependent variable. The empirical study carried out research on the model, establishment of hypotheses, and the statistical treatment. A survey was conducted targeting top management of high-tech venture companies in Daedeok Innopolis; 500 questionnaires were distributed; and, 222 were collected. Results - The human and social capital inherent in top management at venture companies in the early stages of their existence become good evaluation data for those who are invested in similar resources. If top management includes strong human and social capital, access to external resources will be easier; these will have a positive influence on the selection of overnmental support systems; and, this proper support will also have a positive influence on the initial success of the venture company. The results revealed the following. First, it was found that when the educational level and functional background, (the top management human capital), are the output function, top management human capital had a significant influence on selection of governmental R&D support funds. Second, it was found that the internal social capital and external social capital, (the top management social capital), had a significant influence on selection of governmental R&D support tasks. Third, it was found that selection of the governmental R&D support tasks at the start of the venture company had a positive influence on the corporate financial performance such as sales, business profits, and the increase in workers; and, had a significant influence on nonfinancial performance such as market share, competitive position, product competitiveness, and the future product development. Conclusions - Selection of the governmental R&D support system is not recognized as part of the direct sales of a venture company in its early stages, but as it can reduce costs for technical development and helps significantly in creating test products and mass production, it has a positive influence on the company's financial performance and nonfinancial performance as a result. Therefore, companies should take great efforts to frequently be selected as a candidate in the governmental R&D support system, as it can help facilitate R&D that requires extensive funds. As a result, companies can expect effects such as job creation and patent applications and they can advance future product sales.

• 한국정보시스템학회지:정보시스템연구
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• 제7권1호
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• pp.99-128
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• 1998

The increasing importance of IT rose to the top of list of marketing managers' key concerns and IT has been used widely in performing various marketing activities and decisions. However, little was known about how to employ IT in various marketing activities and how to use IT as a strategic marketing means. Also, comprehensive empirical studies have rarely been conducted. This study examines the effectiveness of integrative use of marketing and IT. More specifically, this study attempts to identify the factors that influence the effectiveness of marketing information systems. The manufacturing firms listed in the Korean Stock Market were surveyed. the major findings of this study are as follows. First, the variables of organizational characteristics such as formalization of decision making cooperation between marketing function and IS function, and degree of decentralization were significantly related to the success of marketing information systems. The variables of user highly associated with the success of marketing information systems. Second, it was also found that the support capability of marketing information systems is the major factor of the effectiveness of marketing information systems. Third, the variables marketing function and IS function, and ratio of export sales to total sales were three variables such as marketing knowledge of marketing managers, cooperation were the main factors to affect the users' satisfaction with the information system. These results imply that, in order to increase the effectiveness of marketing information systems, a firm should enhance a cooperation between marketing function and IS function, diversify the support capability of IS, and strengthen the computer mind and computer knowledge of end-uses.