• Journal of Information Processing Systems
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• v.1 no.1 s.1
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• pp.62-69
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• 2005

This paper presents a queuing analysis model of a PC-based software router supporting IPv6-IPv4 translation for residential gateway. The proposed models are M/G/1/K or MMPP-2/G/1/K by arrival process of the software PC router. M/G/1/K is a model of normal traffic and MMPP-2/G/1/K is a model of burst traffic. In M/G/1/K, the arriving process is assumed to be a Poisson process, which is independent and identically distributed. In MMPP-2/G/1/K, the arriving process is assumed to be two-state Markov Modulated Poisson Process (MMPP) which is changed from one state to another state with intensity. The service time distribution is general distribution and the service discipline of the server is processor sharing. Also, the total number of packets that can be processed at one time is limited to K. We obtain performance metrics of PC-based software router for residential gateway such as system sojourn time blocking probability and throughput based on the proposed model. Compared to other models, our model is simpler and it is easier to estimate model parameters. Validation results show that the model estimates the performance of the target system.

• The Journal of Information Systems
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• v.28 no.3
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• pp.203-225
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• 2019

Purpose The purpose of this study is to empirically verify an ePortfolio success model which shows the structural causal relationships among the basic modeling constructs. We developed the success model based on DeLone and Mclean(2003) from IS perspective and on Balaban et al(2013) from ePortfolio perspective. And we are focused on the success of ePortfolio system designed for college students and professors. Design/methodology/approach Structural equation modeling techniques were applied to data collected 375 users of the ePortfolio system, K-Folio, at least one semester during one academic year. The structural model was analyzed using a Lisrel 8.54 statistical program. Findings The followings are the findings of the study. First, the constructs of IS success model are well applied to ePortfolio for college education. Second, the proposed model which has direct causal relationships from ePortfolio's quality to performance is more significant than the D&M and Balaban's model(2013). Third, the information quality among ePortfolio quality constructs does not have effect on system usability and performance. It means that information contents' quality issued by professor or system manager is not satisfied with the students yet. Finally, by using indirect analysis of structural equation model, we found that the ePortfolio operation manager should focus on ensuring system maintenance activities and providing fast and accurate services for improving ePortfolio performance.

• Journal of the Ergonomics Society of Korea
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• v.35 no.4
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• pp.277-291
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• 2016

Objective: The aim of this study is to propose a unit touch gesture model, which would be useful to predict the performance time on mobile devices. Background: When estimating usability based on Model-based Evaluation (MBE) in interfaces, the GOMS model measured 'operators' to predict the execution time in the desktop environment. Therefore, this study used the concept of operator in GOMS for touch gestures. Since the touch gestures are comprised of possible unit touch gestures, these unit touch gestures can predict to performance time with unit touch gestures on mobile devices. Method: In order to extract unit touch gestures, manual movements of subjects were recorded in the 120 fps with pixel coordinates. Touch gestures are classified with 'out of range', 'registration', 'continuation' and 'termination' of gesture. Results: As a results, six unit touch gestures were extracted, which are hold down (H), Release (R), Slip (S), Curved-stroke (Cs), Path-stroke (Ps) and Out of range (Or). The movement time predicted by the unit touch gesture model is not significantly different from the participants' execution time. The measured six unit touch gestures can predict movement time of undefined touch gestures like user-defined gestures. Conclusion: In conclusion, touch gestures could be subdivided into six unit touch gestures. Six unit touch gestures can explain almost all the current touch gestures including user-defined gestures. So, this model provided in this study has a high predictive power. The model presented in the study could be utilized to predict the performance time of touch gestures. Application: The unit touch gestures could be simply added up to predict the performance time without measuring the performance time of a new gesture.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.2
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• pp.1-17
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• 2015

In this paper, we propose a portfolio selection model utilizing a Markov chain for investing in the foreign exchange market based on market forecasts and exchange rate movement predictions. The proposed model is utilized to compute optimum investment portfolio weights for investing in margin-based markets such as the FX margin market. We further present an objective investment algorithm for applying the proposed model in real-life investments. Empirical performance of the proposed model and investment algorithm is evaluated by conducting an experiment in the FX market consisting of the 7 most traded currency pairs, for a period of 9 years, from the beginning of 2005 to the end of 2013. We compare performance with 1) the Dollar Index, 2) a 1/N Portfolio that invests the equal amount in the N target assets, and 3) the Barclay BTOP FX Index. Performance is compared in terms of cumulated returns and Sharpe ratios. The results suggest that the proposed model outperforms all benchmarks during the period of our experiment, for both performance measures. Even when compared in terms of pre- and post-financial crisis, the proposed model outperformed all other benchmarks, showing that the model based on objective data and mathematical optimization achieves superior performance empirically.

• International Commerce and Information Review
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• v.9 no.2
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• pp.231-253
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• 2007

This paper intends to develop an performance evaluation framework of e-trade. The Korea e-trade has been largely attracting many research communities because it brings about e-trade platform which is happening at the early stage of information system maturity. It is true that many research works have been focusing on development issues in e-trade but not much works have been done in e-trade performance study. This paper suggests an e-trade performance framework based on both field and literatures surveys. In addition, an factor analysis model has been introduced to determine that the suggested factors are empirically supporting the hypotheses in the model. Since this paper is opening up many research issues in e-trade performance study many research group could participate in this research area.

• Asia pacific journal of information systems
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• v.13 no.1
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• pp.119-140
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• 2003

The business value of IT has been the focus of the academic and business field in recent years, along with the massive IT investment. Unfortunately, those studies have not been able to demonstrate strong linkages between the IT investment and performance. The impact of IT investment on performance is an important research topic that needs to consider the role of key contextual factors and intermediate factors. This study develops an integrated model for IT investment, with the mediating effects of production/coordination performance towards firm performance. In addition, the model is moderated by some factors like ISP(Information Systems Planning), Business Planning alignment, top management support, IT education and training, and process innovation. The empirical result, based on the moderating regression analysis, indicates that the relationship between IT Investment and production/coordination performance is significantly positive depending on moderating factors. However, production/coordination performance is partially related to firm performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.3
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• pp.115-122
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• 2011

The critical role played by manufacturing performance measurement systems in achieving competitive success is increasingly recognized. Developing an integrated performance measurement model is significant for strategic management. This study consist of several principal steps. Performance criteria from the literature and an questionnaire were utilized prior to building the performance model. The AHP(Analytic Hierarchy Process) is utilized to evaluate the weight of each criterion when generating the performance measurement model for Korea automobile parts manufacturing company. AHP analysis showed clear difference in the priority between 5 criteria and 24 sub-criteria in terms of manufacturing performance of Korean automobile parts manufacturing company. The result of priority evaluation in the 5 criteria of 2nd level was ranked quality, cost, delivery, employee, flexibility. And the critical sub-criteria in the 24 sub-criteria of 3rd level was ranked claim rate, process defect rate, outsourcing parts defect rate, ability to quality management innovation, claim cost, etc.

• ETRI Journal
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• v.45 no.6
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• pp.929-938
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• 2023

The detection of all the symbols transmitted simultaneously in multiuser systems using limited wireless resources is challenging. Traditional model-based methods show high performance with perfect channel state information (CSI); however, severe performance degradation will occur if perfect CSI cannot be acquired. In contrast, data-driven methods perform slightly worse than model-based methods in terms of symbol error ratio performance in perfect CSI states; however, they are also able to overcome extreme performance degradation in imperfect CSI states. This study proposes a novel deep learning-based method by improving a state-of-the-art data-driven technique called deep soft interference cancellation (DSIC). The enhanced DSIC (EDSIC) method detects multiuser symbols in a fully sequential manner and uses an efficient neural network structure to ensure high performance. Additionally, error-propagation mitigation techniques are used to ensure robustness against channel uncertainty. The EDSIC guarantees a performance that is very close to the optimal performance of the existing model-based methods in perfect CSI environments and the best performance in imperfect CSI environments.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.43-50
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• 2020

Many companies around the world are applying CMMI to improve the organization's ability to perform projects, and many others are pushing to obtain CMMI certification as more and more of them are offered as preconditions for participation in projects or supply product. Organizations with high maturity such as CMMI Level 4~5, analyze the accumulated R&D data of the organization and establish the performance management model so that R&D performance is continuously managed. So this paper shows the R&D performance management model made by LIGNex1 which is certificated with CMMI Level 5 organization and the case applied to the project, including its effectiveness.

• Journal of Korean Academy of Nursing Administration
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• v.8 no.2
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• pp.335-346
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• 2002

Purpose: This study is to analyze the relationship between leadership, empowerment, organizational commitment, and nursing performance. Method: The method of the study is the establishment of the analytical framework of the theoretical model and the hypotheses for the empirical survey, analysis of the data collected by the empirical survey, and the provision of a revised model explaining more clearly the causal relationship between variables. Result: Transformational leadership has greater influence on empowerment and nursing performance than transactional leadership. Self determination and impact of empowerment factors greatly influence on organizational commitment, competence and impact significantly influence on nursing performance, and organizational commitment is closely related to the general nursing affair, the human relationship, and the job as an organizational member. Transactional and transformational leadership, in provision of the revised model by verification of goodness-of-fit of the hypothetical model, affects all parts of nursing performance by intervening competence and self determination of empowerment factors. Especially, transactional leadership directly influences on nursing performance without intervening the empowerment factor. Conclusion: The conclusion of the study is transformational leadership exerts a more positive influence on empowerment, organizational commitment, and nursing performance than transactional leadership.