• 한국산학기술학회논문지
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• 제14권10호
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• pp.4719-4725
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• 2013

본 논문에서는 ASM을 이용하여 전기 이륜차 장치에 대한 모델기반 설계 기법을 제시하였다. 실제, 전기 이륜차의 시제품 제작 이전에 전기 이륜차의 최적화와 동력을 예측하기 위해서는 신뢰성을 갖는 해석이 필요하다. 과거의 전기 이륜차 연구는 미시적 관점보다는 거시적 관점에서 실시되었다. 그러나, 본 연구에서는 전기 이륜차 핵심 부품에 대한 상세 해석을 실시하였다. 본 논문에서는 이론과 실험해석의 에러 비율이 2.3%에 달하는 양호한 결과를 얻을 수 있었다. 이 같은 상세 해석을 통하여, 전기 이륜차의 해석 정확도를 향상시키고 설계인자 해석이 가능하게 되었다. 또한, 본 연구에서는 전기 이륜차가 직면하고 있는 Fail safety에 대한 효과적 방법을 제시하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.181-183
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• 2002

The accurate permeability for preform is critical to model and design the impregnation of fluid resin in the composite manufacturing process. In this study, the in-plane and transverse permeability for a woven fabric are predicted numerically through the coupled flow model which combines microscopic with macroscopic flow. The microscopic and macroscopic flow which are flows within the micro-unit and macro-unit cell, respectively, are calculated by using 3-D CVFEM(control volume finite element method). To avoid checker-board pressure field and improve the efficiency on numerical computation, A new interpolation function for velocity is proposed on the basis of analytic solutions. The permeability of plain woven fabric is measured through unidirectional flow experiment and compared with the permeability calculated numerically. Based on the good agreement of the results, the relationships between the permeability and the structures of preform such as the fiber volume fraction and stacking effect can be understood. The reverse and the simple stacking are taken in account. Unlike past literatures, this study is based on more realistic unit cell and the improved prediction of permeability can be achieved. It is observed that in-plane flow is more dominant than transverse flow in the real flow through preform and the stacking effect of multi-layered preform is negligible. Consequently, the proposed coupled flow model can be applied to modeling of real composite materials processing.

• 국제교류와 융합교육
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• 제4권2호
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• pp.43-61
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• 2024

이 연구는 한국의 교육과정 자율화 정책이 결정되고 학교 현장에 적용되는 교육과정 자율화 현상을 설명하는 모형으로서 '통합적 순환모형'을 제외하는데 목적을 두고 있다. 이를 위해 첫째, 교육과정 자율화의 의의와 한국의 교육과정 자율화에 대한 특징을 살펴보았다. 둘째, 정책결정 모형에 대한 비판적 분석을 토대로 대안적 교육과정 정책결정 모형의 필요성에 대해 논의하였다. 셋째, 통합적 순환 모형에 대해 탐색하였다. 여기서는 모형 정립의 조건 탐색과 모형의 기본 방향에 대해 제시하고 통합적 순환 모형을 구안하였다. 통합적 순환 모형은 거시 모형과 미시 모형으로 구분하여 살펴보고 이들을 통합한 모형으로 제시하였다. 논의 결과 우리나라 상황에 적합한 교육과정 정책 모형의 필요, 국가에서 부여한 자율성으로 인한 교육현장의 국가에 대한 자율 요청 행위의 촉진, 외적 개입의 배제와 내적 통제가 확립된 자율성의 개념화가 필요하였다. 이들 논의를 통해 모형 적용의 일반화, 교육과정 질 관리, 검증을 통한 보완 등의 제언을 하였다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2005년도 추계학술대회 및 정기총회
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• pp.321-333
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• 2005

With the limited frequency spectrum and an increasing demand for cellular communication services, the problem of channel assignment becomes increasingly important. However, finding a conflict free channel assignment with the minimum channel span is NP hard. As demand for services has expanded in the cellular segment, sever innovations have been made in order to increase the utilization of bandwidth. The innovations are cellular concept, dynamic channel assignment and hierarchical network design. Hierarchical network design holds the public eye because of increasing demand and quality of service to mobile users. We consider the frequency assignment problem and the base station placement simultaneously. Our model takes the candidate locations emanating from this process and the cost of assigning a frequency, operating and maintaining equipment as an input. In addition, we know the avenue and demand as an assumption. We propose the network about the profit maximization. This study can apply to GSM(Global System for Mobile Communication) which has 70% portion in the world. Hierarchical network design using GA(Genetic Algorithm) is the first three-tier (Macro, Micro, Pico) model, We increase the reality through applying to EMC (Electromagnetic Compatibility Constraints). Computational experiments on 72 problem instances which have 15${\sim}$40 candidate locations demonstrate the computational viability of our procedure. The result of experiments increases the reality and covers more than 90% of the demand.

• 한국산학기술학회논문지
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• 제8권1호
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• pp.73-81
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• 2007

본 논문에서는 마이크로 셀과 매크로 셀이 중첩된 구조를 갖는 이동통신 환경에서 핸드오버의 성능을 분석하였다. 제안한 모델에서는 고속으로 이동하는 가입자를 마이크로 셀로 핸드오버하지 않고 매크로 셀로 핸드오버하는 경우의 성능을 분석하였다. 분석의 용이함을 위해 마이크로 셀과 매크로 셀의 모양은 원형이라고 가정하였다. 마이크로 셀에는 저속의 핸드오버 호를 위하여 큐를 두는 방식과 매크로 셀에는 고속의 핸드오버 호를 위하여 예약채널 할당방식을 적용하였다 해석적인 분석결과, 제안한 방식에서 새로운 호의 블러킹 확률의 증가는 미비하면서 랜드오버 실패 확률은 중첩되지 않은 셀 구조를 갖는 시스템에 비해 상대적으로 낮음을 알 수 있었다.

• The Journal of Asian Finance, Economics and Business
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• 제8권12호
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• pp.19-29
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• 2021

This study aims to measure financial inclusion and examine its impact on income inequality in a panel of 18 Asian countries over the period 1997-2017. Two alternative approaches for developing financial inclusion index are used: one approach following the methodology of Sarma (2008), while the other is the Dynamic Factor Model (DFM)-based index. The impact of individual indicators and index of financial inclusion on inequality in income is analyzed. The Generalized Method of Moment (GMM) approach is used for empirical analysis. The results indicate that micro-level financial inclusion has a weak negative and statistically significant impact on income inequality. Macro-level index and all individual indicators of financial inclusion do not affect income inequality in the selected sample of economies. The income inequality issues have different natures and cannot be fixed by financial inclusion only. It needs holistic structural reforms to enable fair distribution of income and make an equitable financial system. Financial inclusion is a relatively less important intervention tool regarding fixing the issue of income inequality. This is one of the first studies that used the DFM method for financial inclusion indices construction.

• International Journal of Computer Science & Network Security
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• 제23권9호
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• pp.37-46
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• 2023

The main aim of the article is to solve the problem of automating price monitoring using marketing forecasting methods and Excel functionality under martial law. The study used the method of algorithms, trend analysis, correlation and regression analysis, ANOVA, extrapolation, index method, etc. The importance of monitoring consumer price developments in market pricing at the macro and micro levels is proved. The introduction of a Dummy variable to account for the influence of martial law in market pricing is proposed, both in linear multiple regression modelling and in forecasting the components of the Consumer Price Index. Experimentally, the high reliability of forecasting based on a five-factor linear regression model with a Dummy variable was proved in comparison with a linear trend equation and a four-factor linear regression model. Pessimistic, realistic and optimistic scenarios were developed for forecasting the Consumer Price Index for the situation of the end of the Russian-Ukrainian war until the end of 2023 and separately until the end of 2024.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.496-500
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• 2015

International construction projects are inherently more risky than domestic projects with multi-dimensional uncertainties that require complementary risk management at both the country and project levels. However, despite a growing need for systematic country evaluations, most studies have focused on project-level decisions and lack country-based approaches for firms in the construction industry. Accordingly, this study suggests data-driven approaches for evaluating countries using two quantitative models. The first is a two-stage country segmentation model that not only screens negative countries based on country attractiveness (macro-segmentation) but also identifies promising countries based on the level of past project performance in a given country (micro-segmentation). The second is a multi-criteria country segmentation model that combines a firm's business objective with the country evaluation process based on Kraljic's matrix and fuzzy preference relations (FPR). These models utilize not only secondary data from internationally reputable institutions but also performance data on Korean firms from 1990 to 2014 to evaluate 29 countries. The proposed approaches enable firms to enhance their decision-making capacity for evaluating and selecting countries at the early stage of corporate strategy development.

• 경영정보학연구
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• 제7권2호
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• pp.117-128
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• 2005

본 연구는 철강제조 분야에서 제품 생산 중 발생하는 모든 데이터를 실시간으로 수집하여 데이터베이스화하고, 웹 기반 시스템을 구축함으로써 시간과 장소의 제약 없이 필요 데이터를 조회, 분석할 수 있는 시스템 개발에 대한 연구이다. 본 시스템의 구축 결과, 실시간으로 데이터의 조회 및 분석이 가능하게 됨으로써 생산 제품에 대한 보다 효율적인 품질개선 활동이 가능하게 되었고, 제품의 신뢰도를 높일 수 있게 되었다. 또한 장기간 누적된 데이터를 데이터베이스화하고 그것을 통계적으로 분석 가능하게 함으로써 새로운 제어모델의 개발과 조업기술의 개발이 보다 용이하게 되었고, 신제품 개발의 기초자료로도 활용할 수 있게 되었다.

• Geomechanics and Engineering
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• 제7권2호
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• pp.183-200
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• 2014

The expansivity of clayey soils is a complicated phenomenon which may affect the stability of geotechnical structures and geo-environmental projects. In all common factors for the monitoring of soil expansion, less attention is given to anion type of pore space solutions. Therefore, this paper is concerned with the impact of various concentrations of different inorganic salts including NaCl, $Na_2SO_4$, and $Na_2CO_3$ on the macro and microstructure behavior of the expandable smectite clay. Comparison of the responses of the smectite/NaCl and smectite/$Na_2SO_4$ mixtures indicates that the effect of anion valance on the soil engineering properties is not very pronounced, regardless of the electrolyte concentration. However, at presence of carbonate as potential determining ions (PDIs) the swelling power increases up to 1.5 times compared to sulfate or chloride ions. The samples with $Na_2CO_3$ are also more deformable and show lower osmotic compressibility than the other mixtures. This demonstrates that the barrier performance of smectite greatly decreases in case of anions with the non-specific adsorption (e.g., $Cl^-$ and $SO{_4}^{2-}$) as the salinity of solution increases. Based on the results of the X-ray diffraction and sedimentation tests, the high soil volumetric changes upon exposure to carbonate is attributed to an increase in the repulsive forces between smectite basic unit layers due to the PDI effect of $CO{_3}^{2-}$ and increasing the pH level which enhance the buffering capacity of smectite. The study concluded that the nature of anion through its influence on the re-arrangement of soil microstructure and osmotic phenomena governs the hydro-mechanical parameters of expansive clays. It seems not coinciding with the double layer theory of the Gouy-Chapman double layer model.