• Journal of the Korea Society for Simulation
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• v.21 no.1
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• pp.69-79
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• 2012

One of the goals of mass customization is to permit changes in the product to meet specific customer requirements without substantially impacting the cost or delivery schedule. In large assembly manufacturing industries, such as shipbuilding and commercial airplane production, customization takes place by changing components and/or modules, sometimes called interim products. Using shipbuilding as a case study, it is possible to study the impact of such changes using mass customization principles on the schedule. In large assembly manufacturing, mass customization changes would cause changes in engineering time and production time, based on the amount of change required by the customization. This work first proposes a structure for implementing mass customization in shipbuilding and then uses simulation of a simplified, theoretical shipbuilding process to evaluate the impacts of various levels of change on delivery performance.

• International Area Studies Review
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• v.13 no.3
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• pp.759-780
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• 2009

The purpose of this paper is to analyse the effect of Korean FDI(1990-2008) in China by industries on exports and imports between two countries. We use time series regression, Vector Error Correction Model and Impulse Response Function as methodologies. Our findings through empirical tests are as follows. First Korean FDI in China increases Korean exports with China but shows a tendency to decrease due to the local content of China. Second Korean FDI in China increases Korean imports in SITC 8 with China. Finally Korean trade surplus caused by Korean FDI in China shrinks due to the decreasing of exports and increasing of imports in Korea. Korean FDI in China should be oriented host country's market oriented rather than production efficiency oriented because of unfriendly foreign investment environments in China.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.3
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• pp.31-38
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• 2019

In this paper, we design a green supply chain (gSC) network model. For constructing the gSC network model, environmental and economic factors are taken into consideration in it. Environmental factor is to minimize the $CO_2$ emission amount emitted when transporting products or materials between each stage. For economic factor, the total cost which is composed of total transportation cost, total handling cost and total fixed cost is minimized. To minimize the environmental and economic factors simultaneously, a mathematical formulation is proposed and it is implemented in a genetic algorithm (GA) approach. In numerical experiment, some scales of the gSC network model is presented and its performance is analyzed using the GA approach. Finally, the efficiencies of the gSC network model and the GA approach are proved.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.20 no.4
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• pp.191-204
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• 2009

It is essential to estimate and evaluate for user satisfaction and quality management of database system, understanding of user needs and quality characteristics. Based on ISO 25000 series, it was suggested, the first research, that 5 main quality characteristics, 21 sub quality characteristics and 48 internal quality characteristics. There are comparative significance methods of main quality characteristics, sub quality characteristics and internal quality characteristics but it is not easy to use directly quality model in database system industry field. Also, Considering time and cost in quality evaluation, it is impossible to evaluate 48 internal quality characteristics and its level of quality evaluation is not equal in accordance with integrity level of database system. By using AHP, this study presents selection method of quality characteristics in weight and possibility of application quality model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.12
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• pp.1150-1159
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• 2011

Reliability is defined as a probability that a system will operate properly for a specified period of time under the design operating conditions without failure. Reliability-Redundancy Optimization Problem(RROP) involves selection of components with multiple choices, redundancy levels and redundancy strategy(Active or Standby) for maximizing system reliability with constraints such as cost, weight, etc. Based on the design configuration of Multi-Spectral Camera(MSC) system of KOMPSAT-2, the mathematical programming model for RROP is suggested in this study. Due to the nature of RROP, i.e. NP-hard problem, Parallel Particle Swarm Optimization(PPSO) algorithm is proposed to solve it. The result of the numerical experiment for RROP is presented as instance of recommended design configuration at some mission time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.740-743
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• 2010

본 논문에서는 홀 효과를 이용하여 차축(Tone Wheel) 회전에 따른 자속밀도의 변화를 감지하여 속도를 검출하는 자동차용 차륜 속도센서를 개발 제작하였다. 개발된 센서는 능동형 차속센서로서 마그네트 내장형 2-wire 홀 IC와 케이블 연결부를 ABS를 이용 하우징한 모형 구조로 제작 실험하였다. 기존의 능동형 차속센서 중 1개사의 자동차용 차속센서 부품의 특성을 분석하여 본 논문에서 제작한 센서와 각 특성을 비교하였다. 본 논문에서 개발된 차속센서는 12km/h 이하에서의 최소 감지스피드 성능, $80^{\circ}C$이하의 작동온도, 49% ~ 51%의 듀티 사이클$[T_{on}/(T_{on}+T_{off})]$ 동작 특성을 보였다. 본 논문에서 제작한 능동형 차속센서는 수동형과 비교하여 부품수가 적고 소형화 및 경량화, 에어 갭(Air Gap) 변화에도 민감하지 않으며 듀티 사이클과 저속에서의 검출능력이 우수한 특성을 지닌다.

• Journal of Korean Society for Quality Management
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• v.39 no.4
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• pp.507-515
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• 2011

MIL-HDBK-217 has played a pivotal role in reliability prediction of electronic equipments for more than 30 years. Recently, RIAC developed a new methodology $217Plus^{TM}$which officially replaces MIL-HDBK-217. Sensitivity analysis of the 217Plus component models to various parameters has been performed and meaningful observations have been drawn in this study. We first briefly reviewed the $217Plus^{TM}$ methodolog and compared it with the conventional model, MIL-HDBK-217. We then performed sensitivity analysis $217Plus^{TM}$ component models to various parameters. Based on the six parameters and an orthogonal array selected, we have performed indepth analyses concerning parameter effects on the model. Our result indicates that, among various parameters, operating temperature and temperature rise during operation have the most significant impacts on the life of a component, and thus a design robust to high temperature is the most importantly required. Next, year of manufacture, duty cycle, and voltage stress are weaker but may be significant when they are in heavy load conditions. Although our study is restricted to a specific type of diodes, the results are still valid to other cases. The results in this study not only figure out the behavior of the predicted failure rate as a function of parameters but provide meaningful guidelines for practical applications.

• Composites Research
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• v.15 no.6
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• pp.38-43
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• 2002

Rapid Prototyping(RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys' Fused Deposition Modeling(FDM) is a typical RP process that can fabricate prototypes out of plastic materials, and the parts made from FDM were often used as load-carrying elements. Because FDM deposits materials in about 300$\mu$m thin filament with designated orientation, parts made from FDM show anisotropic material properties. In this paper an analytic model was proposed to predict the tensile strength of FDM parts. Applying the Classical Lamination Theory, which was developed for laminated composite materials, a computer code was implemented. Tsai-Wu failure criterion was added to the code to predict the failure of the FDM parts. The tensile strengths predicted by the analytic model were compared with experimental data. The data and prediction agreed reasonably well to prove the validity of the model. In addition, a web-based advisory service(FDMAS) was developed to provide strength prediction and design rules for FDM parts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1113-1118
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• 2010

It is requested that the interior compartment of a passenger vehicle must be satisfied with the FMVSS201U regulation, FMH impact test. It is needed the design methodology to find the appropriate structure about the FMH impact. When designing the impact-absorbing structure for the FMH impact test, it is to be noted that the impact absorber must have different performance considering the stiffness of the vehicle as the impact position and approach angle of FMH. In this study, an efficient design methodology was developed by using subcomponent collapse simulation instead of conducting full-vehicle simulation, thereby reducing the time and resources spent. Further, this unit-model simulation helps optimize the impact absorbing structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1243-1248
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• 2018

Metal Powder Metallurgy is a manufacturing technology that makes unique model parts or a certain type of product by using a hardening phenomenon when a powder of metal or metal oxide is put it into a mold and compression-molded by a press and then heated and sintered at a high temperature. Powder metallurgical press equipment is mainly used to make the parts of automobile, electronic parts and so on, and most of them are manufactured using precise servo motor. The intelligent precision servo control powder molding press system which is designed and implemented in this paper has advantages of lowering the price and maintaining the precision by using the mechanical camshaft for the upper ram part and precisely controlling the lower ram part using the high precision servo system. In addition, OPC-based monitoring and process data collection systems are designed and implemented to provide scalability that can be applied to smart manufacturing management systems that utilize Big Data in the future.