• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.481-504
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• 2006

VaR, a tail-related risk measure is now widely used as a tool for a measurement and a management of financial risks. For more accurate measurement of VaR, recently we are particularly concerned about the approach based on extreme value theory rather than the traditional method based on the assumption of normal distribution. However, many studies about the approaches using extreme value theory was done only for the univariate case. In this paper, we discuss portfolio risk measurements with modelling multivariate extreme value distributions by combining copulas and extreme value theory. We also discuss the estimation of ES together with VaR as portfolio risk measures. Finally, we investigate the relative superiority of EVT-copula approach than variance-covariance method through the back-testing of an empirical data.

• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.859-873
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• 2008

Job satisfaction impacts on the turnover intention of employee, which affects the turnover behavior. This paper concerns with the impact of job satisfaction on the turn over behavior. Since turnover intention is highly correlated with job satisfaction, salary, employment status and etc, we should pay careful attention for modelling of those variables as independent variables and the turnover behavior as a dependent variable in the empirical study for the impact of factors on turnover behavior. We detect significant variables which effect the turnover behavior using 2-stage logistic regression inserting the turnover intention, an independent variable, with the chance estimates derived from the instrumental variables in Graduates Occupational Mobility Survey.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.230-238
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• 1999

This paper describes a research work of developing computer-aided design of lead frame, semiconductor, with blanking operation which is very precise for progressive working. Approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. This system has been written in AutoLISP on the AutoCAD using a personal computer and in I-DEAS Drafting Programming Language on the I-DEAS Master Series Drafting with Workstation, HP9000/715(64) and tool kit on the ESPRIT. Transference of data among AutoCAD, I-DEAS Master Series Drafting, and ESPRIT is accomplished by DXF(drawing exchange format) and IGES(initial graphics exchange specification) methods. This system is composed of six modules, which are input and shape treatment, production feasibility check, strip-layout, die-layout, modelling, and post-processor modules. The system can design process planning and Die design considering several factors and generate NC data automatically according to drawings of die-layout module. As forming process of high precision product and die design system using 2-D geometry recognition are integrated with technology of process planning, die design, and CAE analysis, standardization of die part in die design and process planning of high pression product for semiconductor lead frame is possible to set. Results carried out in each module will provide efficiencies to the designer and the manufacturer of lead frame, semiconductor.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.4
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• pp.61-72
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• 2013

The relationship between export growth and economic growth in developing countries has been one of the main issues in the growth theory field. Many of empirical studies have been done during the last three decades in order to investigate the export-led growth hypothesis using either time-series or cross-sectional data mainly in developing countries. This paper applies cointegration and error correction models to test causal relationship between export growth and economic growth in the Korean 8 manufacturing industries using the industrial time-series quarterly data over 1975-2010. The export-output relationship is tested by including industrial capital stock and the industrial labor force as exogenous variables. The cointegration and error-correction modelling technique with industrial export and output data have showed the strong evidence that there is a bi-directional causality between industrial export and industrial output in 6 manufacturing industries except wood & pulp and nonmetallic industries.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.131-145
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• 2014

This study is an empirical analysis on the relationship between social presence and online community users' continuance intention. Based on Bhattacherjee(2001)'s expectation-confirmation model (ECM) of IT continuance model, we test the influence of social presence on one's intention to continue using online communities. This study sampled 132 online community users. Research hypotheses are tested using the structural equation modelling(SEM) approach. The results of this study demonstrate that user satisfaction is influenced by perceived usefulness and perceived enjoyment. But, the confirmation of expectation did not affect user satisfaction. And, social presence has direct effects on perceived usefulness and perceived enjoyment. Further, social presence has a positive effect on users' continuance intention through mediating effect of perceived usefulness. This study suggests that perceived usefulness should be taken into account when carrying out the operating strategy of online communities.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.80-91
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• 2017

The purpose of paper is to confirm the role of E-WOM(Electronic Worth of Mouth) in decision making of selecting the mobile application via smart-phone or tablet pc. Particularly i wished to confirm the effects of others' positive or negative reviews in purchasing(free downloading) mobile applications. To resolve these research questions, the secondary data or previous research were collected and arranged theoretically. From literature research, i made out the proposed model to explain the relationships between the variables, executed the operational definitions and 14 Hypotheses were established, collected the survey data of 228 mobile application users. Using the empirical test analysis, previous performances to confirm the construct validity and internal consistency and PLS(Partial Least Square) modelling method was executed. The test result showed that proposed relations of variables was empirically identified, therefore, i got the conclusion as followings; First, attributes of mobile application users' reviews have the effects positively to usefulness perception and expected performance. Second, it was significantly tested Usefulness of Online Review and Expected Performance. Second, Usefulness of Online Review, Source Credibility and Expected Performance have effect positively to Intention of Review Adoption.

• Tunnel and Underground Space
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• v.17 no.6
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• pp.438-447
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• 2007

This technical report is to introduce the research on SRM (Synthetic Rock Mass) which was presented in 2007 ISRM Congress at Lisbon by Prof, Fairhurst who speak with emphasis on its importance and potential in rock engineering. The Synthetic Rock Mass approach to jointed rock mass characterization (Pierce et al. 2007) is reviewed relative to existing empirical approaches and current understanding of jointed rock mass behaviour. The review illustrates how the key factors affecting the mechanical behaviour of jointed rock masses may be considered and demonstrates that the SRM approach constitutes a significant step forward in this field. This technique, based on two well-established methods, Bonded Particle Modelling in PFC-3D (Potyondy and Cundall, 2004) and Discrete Fracture Network simulation, employs a new sliding joint model that allows for large rock volumes containing thousands of pre-existing joints to be subjected to any non-trivial stress path. Output from SRM testing includes rock mass brittleness and strength, evolution of the full compliance matrix and primary fragmentation.

• Journal of Korea Port Economic Association
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• v.34 no.1
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• pp.99-110
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• 2018

This study empirically examines simple methodology to quantify the risk resulted from the uncertainty of bunker price and foreign exchange rate, which cause main resources of the cost in shipping industry during the periods between $1^{st}$ of January 2010 and $31^{st}$ of January 2018. To shed light on the risk measurement in cash flows we tested GBM(Geometric Brownian Motion) frameworks such as the model with conditional heteroskedasticity and jump diffusion process. The main contribution based on empirical results are summarized as following three: first, the risk analysis, which is dependent on a single variable such as freight yield, is extended to analyze the effects of multiple factors such as bunker price and exchange rate return volatility. Second, at the individual firm level, the need for risk management in bunker price and exchange rate is presented as cash flow. Finally, based on the scale of the risk presented by the analysis results, the shipping companies are required that there is a need to consider what is appropriate as a means of risk management.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.3
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• pp.137-147
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• 2011

In this study, an analysis was conducted to investigate the process how information technology(IT) quality affects organizational performance. Acquisition of IT by itself is not sufficient for the improvement of organizational performance, which additionally requires the operations activity using IT to meditate between IT and organizational performance. This study classified the IT quality into functional quality and operational quality. The functional quality is defined as intrinsic characteristics of IT itself while the operational quality is defined as effective support of IT for organizational management activities. Our research model proposed that the functional quality has indirect effect meditated by the operational quality on organizational performance. The statistical test using structural equation modelling in empirical research showed insignificant direct effect and significant indirect meditation effect of the functional quality on organizational performance via the operational quality. This paper concludes with contribution of this study, managerial implication of the research findings and further research issues.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.9-14
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• 2011

This Paper proposed the prediction method of fuel consumption from vehicle informations through OBD-II Interface. We assumed RPM, TPS had a relationship with fuel consumption. We got the output as fuel-consumption from a vehicle RPM, TPS as input by using polynomial equation. We had modelling as quadric function with OBD-II data and fuel consumption data supported by automotive company in real. In order to verify the effectiveness of proposed method, 5 km real road-test was performed. The results showed that the proposed method can estimate precisely the fuel consumption from vehicle multi-data.