• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.909-915
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• 2009

In this paper, a study of performance improvement for a centrifugal vertical pump having specific speed of 330 is introduced. The existing model has high efficiency but needs better NPSH required performance. Such that new pump model is designed to obtain larger suction specific speed. 6 design parameters considered to affect pump performance are selected for impeller design. Key design parameters are investigated using by design of experiments and CFD, and impeller inlet diameter is increased to get better suction performance. The amount of inlet diameter increase is determined by using cavitation analysis. The results show that new design model has higher efficiency and better NPSH required performance than the existing model.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.63-79
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• 2002

During the last decade many enterprises spent a huge amount of money for investment on Information Technology (IT) & Information System (IS) to attain competitive advantage and to maximize their business performance by satisfying the various requirements of customers. Under such circumstances, methodologies for evaluating IT impact on business performance are very important issues for strategic decision making on investment. In this study, we propose a performance evaluation model that adopts the concept of the Balanced Scorecard (BSC) and the Value Chain to analyze the financial impact and non-financial impact of IT & IS at each critical work area. This model combines the 4 evaluation areas from BSC and 6 critical work areas from Value Chain and measures the Key Performance Indicator (HPI) and the effect of KPI. Also, we present a case study of which the evaluation model has been conducted on a major manufacturing company. finally. we address some important notes to improve the IT & IS performances in the real-world.

• The Journal of Information Systems
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• v.29 no.1
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• pp.137-158
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• 2020

Purpose This study aims to analyze how entrepreneurs' morality affects entrepreneurship and social responsibility. The purpose of this study is to analyze the differences of entrepreneurship and social responsibility on corporate financial performance and social performance by measuring entrepreneurial morality index. Design/methodology/approach The research model is based on the existing literature related to morality, entrepreneurship, social responsibility, and corporate performance. In order to verify the research model, empirical analysis was conducted. The collected data were analyzed by Smart-pls 2.0 based on the structural equation model based measurement model verification and the structural model verification two - step approach. Using the bootstrapping method of PLS, 500 samples were constructed and hypothesis verification was performed. Findings The results of this study are as follows. In the case of general manufacturing companies, business people are more focused on improving corporate performance than morality, and have a somewhat consistent effect with entrepreneurial spirit that does not have a space of morality. When entrepreneurship is strengthened, financial performance and social performance. Business entrepreneurs in social enterprises are more aware of social responsibility than entrepreneurship, so they achieve both financial performance and social performance at the same time. As a result of this study, it was found that there is a difference in perception depending on the morality of the business people, entrepreneurship, social bookkeeping, and management performance according to the type of company.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.1
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• pp.161-177
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• 2013

High-speed vessels require good resistance and seakeeping performance for safe operations in rough seas. The resistance and seakeeping performance of high-speed vessels varies significantly depending on their hull forms. In this study, three planing hulls that have almost the same displacement and principal dimension are designed and the hydrodynamic characteristics of those hulls are estimated by high-speed model tests. All model ships are deep-V type planing hulls. The bows of no.2 and no.3 model ships are designed to be advantageous for wave-piercing in rough water. No.2 and no.3 model ships have concave and straight forebody cross-sections, respectively. And length-to-beam ratios of no.2 and no.3 models are larger than that of no.1 model. In calm water tests, running attitude and resistance of model ships are measured at various speeds. And motion tests in regular waves are performed to measure the heave and pitch motion responses of the model ships. The required power of no.1 (VPS) model is smallest, but its vertical motion amplitudes in waves are the largest. No.2 (VWC) model shows the smallest motion amplitudes in waves, but needs the greatest power at high speed. The resistance and seakeeping performance of no.3 (VWS) model ship are the middle of three model ships, respectively. And in regular waves, no.1 model ship experiences 'fly over' phenomena around its resonant frequency. Vertical accelerations at specific locations such as F.P., center of gravity of model ships are measured at their resonant frequency. It is necessary to measure accelerations by accelerometers or other devices in model tests for the accurate prediction of vertical accelerations in real ships.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.413-418
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• 2020

It is necessary to manage the prediction accuracy of the machine learning model to prevent the decrease in the performance of the grid network condition prediction model due to overfitting of the initial training data and to continuously utilize the prediction model in the field by maintaining the prediction accuracy. In this paper, we propose an automation technique for maintaining the performance of the model, which increases the accuracy and reliability of the prediction model by considering the characteristics of the power grid state data that constantly changes due to various factors, and enables quality maintenance at a level applicable to the field. The proposed technique modeled a series of tasks for maintaining the performance of the power grid condition prediction model through the application of the workflow management technology in the form of a workflow, and then automated it to make the work more efficient. In addition, the reliability of the performance result is secured by evaluating the performance of the prediction model taking into account both the degree of change in the statistical characteristics of the data and the level of generalization of the prediction, which has not been attempted in the existing technology. Through this, the accuracy of the prediction model is maintained at a certain level, and further new development of predictive models with excellent performance is possible. As a result, the proposed technique not only solves the problem of performance degradation of the predictive model, but also improves the field utilization of the condition prediction model in a complex power grid system.

• Journal of the Korean Society for Library and Information Science
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• v.41 no.1
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• pp.85-103
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• 2007

Information literacy which is related various forms of literacy can be defined as a vital competency of individuals in digital based knowledge information society. This basic survey research is aimed to assess information literacy level of the undergraduate students. For this study a proper model of information literacy is used which based 5 Performance processes and 12 performance abilities. The result of this survey is as follows: 1) Among the S performance process elements.'result evaluation' element showed high level competency than other elements. 2) There were high correlations within performance Process elements and performance ability elements. 3) Those items such as academic grade, first experience of information retrieval, and experience of information literacy instruction affect the difference in the level of information literacy.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.165-172
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• 2011

In this paper, we introduce an integrated performance evaluation model defined by the three indices (evaluation index for each evaluation stage, performance viewpoint, and performance type) and analyze the utilization and satisfaction of the seven public u-IT services implemented from 2008 to 2009 using the proposed model. From the performance results of the public u-IT services, it was found out that most of the research goals initially set by the public u-IT service support projects were satisfied. Furthermore, we suggest improvement directions and promotion strategies of future projects.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.578-585
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• 2012

Reciprocating engine is widely used for small propeller driven aircraft. because it is the superior efficiency and low price. Currently, reciprocating engine is used for the development of KC-100, LSA, PAV, UAV in domestic. In this study, Naturally aspirated engine and turbocharger engine performance model is developed. The propeller is designed and analyzed at cruise condition of reciprocating engine aircraft using optimum method, the propeller performance model is developed. The Integrated propulsion performance model is developed, through the matching with engine and propeller performance model, for small reciprocating engine aircraft performance analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.12-16
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• 2007

A dynamic model of proton exchange membrane fuel cell(PEMFC) system is designed to understand the performance of the PEMFC in residential power generator(RPG) over various balance of plant(BOP) options. In particular, since the performance of PEMFC system should be optimized for given operating ranges, it is necessary to design suitable BDP components which can support the operating ranges. The objective of this study is to develop a dynamic system model for the study of PEMFC performance over various BOP options. Therefore, a dynamic model is composed of a PEMFC stack model, a water management system model, a thermal management system model and a fuel/air supply model and the model is integrated under SIMULINK(R)environment. Basic simulation results will be presented.

• Korean Management Science Review
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• v.23 no.2
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• pp.93-107
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• 2006

This paper attempts to improve the typical DEA model that is often used as a performance evaluation method for service firms. The after-sales service system in a Korean electronic company is chosen as a sample case. The performance evaluation method currently practiced in the firm was reviewed and some critical issues of the current method were discussed. DEA model would be considered a solution for solving those Issues. However, typical DEA models has various drawbacks in determining the weights over evaluation criteria. Proposed is the priority-constrained DEA model that accommodates the strategic Importance of each evaluation criterion. The results of the proposed model are compared with those of typical DEA models. It is shown that the priority-constrained DEA model is superior to the others in terms of evaluation quality.