• ETRI Journal
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• 제25권2호
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• pp.65-72
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• 2003

To achieve cost and size reductions, we developed a low cost manufacturing technology for RF substrates and a high performance passive process technology for RF integrated passive devices (IPDs). The fabricated substrate is a conventional 6" Si wafer with a 25${\mu}m$ thick $SiO_2$ surface. This substrate showed a very good insertion loss of 0.03 dB/mm at 4 GHz, including the conductive metal loss, with a 50 ${\Omega}$ coplanar transmission line (W=50${\mu}m$, G=20${\mu}m$). Using benzo cyclo butene (BCB) interlayers and a 10 ${\mu}m$ Cu plating process, we made high Q rectangular and circular spiral inductors on Si that had record maximum quality factors of more than 100. The fabricated inductor library showed a maximum quality factor range of 30-120, depending on geometrical parameters and inductance values of 0.35-35 nH. We also fabricated small RF IPDs on a thick oxide Si substrate for use in handheld phone applications, such as antenna switch modules or front end modules, and high-speed wireless LAN applications. The chip sizes of the wafer-level-packaged RF IPDs and wire-bondable RF IPDs were 1.0-1.5$mm^2$ and 0.8-1.0$mm^2$, respectively. They showed very good insertion loss and RF performances. These substrate and passive process technologies will be widely utilized in hand-held RF modules and systems requiring low cost solutions and strict volumetric efficiencies.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2008년도 춘계학술대회
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• pp.590-594
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• 2008

산업의 융합화 추세는 IT서비스 산업이 복잡한 서비스 시스템 통합과 더불어, 제품과 서비스의 융/복합화를 위한 PSS(Product Service System) 구현에 많은 노력을 요구하는 동인으로 작용하고 있다. 이는 제품의 서비스화(product servicize)와 서비스의 제품화(service productize) 현상의 가속화로 인해 제품과 서비스의 구분이 모호해지고 있는 산업변화에 대응하려는 산업의 노력으로 판단된다. 고객 가치 향상을 위해 IT서비스 제조산업(IT Service manufacturing)에서는 제품과 서비스의 모호한 경계를 극복하고, 서비스중심의 신규 IT서비스를 개발할 수 있는 무형의 프로세스 정립이 요구된다. 본 연구에서는 서비스 사이언스 측면에서 제공되는 기법들(PSS, NPD, NSD, UCD, Contingency theory)을 검토하여, IT서비스 제조산업의 특성이 반영된 마케팅 지원 process tool을 개발하는 데에 목적이 있다. 제안된 tool은 목표시장 및 기술환경의 분석과 동시에 IT서비스 제품 분석을 통해 IT서비스 사업 마케팅 기회를 전략적으로 탐색할 수 있는 도구가 될 수 있을 것으로 판단된다.

• Journal of Welding and Joining
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• 제33권4호
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• pp.1-6
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• 2015

Advances in laser technology have yielded a multitude of innovative processes and applications in various industries. Laser peening is a typical example invented in the mid-1990s as a surface technology, which converted residual stress from tension to compression by just irradiating successive laser pulses to metallic materials under aqueous environment without any surface preparation. The effects of laser peening have been experimentally studied on residual stress, stress corrosion cracking(SCC) susceptibility and fatigue properties with water-penetrable frequency-doubled Nd:YAG laser. In addition, laser peening has been widely used in aviation and aerospace industries, automobile manufacturing and nuclear plant. One of the most important causes to improve the above-mentioned properties is the deeper compressive residual stress induced by laser peening. Taking advantage of the process without reacting force against laser irradiation, a remote operating system was developed to apply laser peening to nuclear power reactors as a preventive maintenance measure against SCC.

• 경영과학
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• 제32권1호
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• pp.35-47
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• 2015

The purpose of this paper is to find an optimal weaving connection method of sweater threads while weaving intarsia sweater by the genetic algorithm. The objective function was devised to minimize labor cost and lessen the amount of thread usage. In order to create the parental population group in the genetic algorithm, we developed five thread connection methods. Besides, elite chromosome screening methods for the offspring group was selected both to the whole chromosome thread elite and to a color-coded elite thread chromosome. Commonly used diamond pattern in Intarsia sweater manufacturing was applied to the experiments. The experimental results showed that thread system saved the labor and material costs than woven method under the existing software. When weaving Intarsia sweater in the field, we can apply the developed genetic algorithm to improve productivity of weaving connection method.

• 품질경영학회지
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• 제47권4호
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• pp.823-835
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• 2019

Purpose: This study deals with a production planning and scheduling problem to minimize the total weighted tardiness on hybrid flow shop with sets of non-identical parallel machines on stages, where parallel machines in the set are dedicated to perform specific subsets of jobs and sequence-dependent setup times are also considered. Methods: A two-stage approach, that applies MILP model in the 1st stage and dispatching rules in the 2nd stage, is proposed in this paper. The MILP model is used to assign jobs to a specific machine in order to equalize the workload of the machines at each stage, while new dispatching rules are proposed and applied to sequence jobs in the queue at each stage. Results: The proposed two-stage approach was implemented by using a commercial MILP solver and a commercial simulation software and a case study was developed based on the spark plug manufacturing process, which is an automotive component, and verified using the company's actual production history. The computational experiment shows that it can reduce the tardiness when used in conjunction with the dispatching rule. Conclusion: This proposed two-stage approach can be used for HFS systems with dedicated machines, which can be evaluated in terms of tardiness and makespan. The method is expected to be used for the aggregated production planning or shop floor-level production scheduling.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.44-55
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• 2004

In order to meet the requirement for higher thickness accuracy in tandem cold rolling processes, it is strongly necessary to have good performance in control units. To meet this requirement, this paper suggested an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation and roll eccentricity simultaneously as the major disturbances, a synthesis of multivariable control systems was presented based on H$\infty$ control theory, which could reflect the knowledge of input direction and spectrum of disturbance signals on design. Then, to effectively reject roll eccentricity, a weight function having some poles on the imaginary axis was introduced. This lead to a non-standard H$\infty$ control problem, and the design procedures for solving this problem were analytically presented. The effectiveness of the proposed control method was evaluated through computer simulations and compared to that of the conventional linear quardratic control and feedforward control methods for roll eccentricity.

• 한국경영과학회지
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• 제22권2호
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• pp.79-97
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• 1997

Many dispatching rules have been developed for the on-line control of product flow in a job shop. The introduction of a flexible manufacturing system (FMS) has added a new requirement to classical job shop control problem : the selection of machines by parts of different types. An FMS can keep a great deal of information on the status of the system, such as information on what is scheduled in the near future, with great accuracy. For example, the knowledge of the time when the next part will arrive at each machine can be neneficial for the routing. This paper tests the effects of the use of this knowledge for part routing on the parts flow time (sum of the time for waiting and service) under a simple routing procedure- a look-ahead routing procedure. A test under many operating conditions shows that the reduction of part flow time from the cases without using this information is between 1% and 11%, which justifies more study on this routing procedure at real production sites when machine capacity is a critical issue. The test results of this paper are also valid for other highly automated systems such as the semi-conductor fabrication plants for routing when the arrivals of parts in the near future are known.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 춘계종합학술대회
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• pp.340-347
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• 1999

최근 산업화로 인하여 물류 자동화에 많은 관심이 집중되고 있다. 지금까지는 컨베이어 벨트가 물류 자동화에 있어서 가장 많이 사용되었지만 이 시스템은 공간을 많이 차지하고, 비용이 많이 든다는 단점을 가지고 있다. 본 논문은 퍼지를 이용한 새로운 자율 주행 제어 알고리즘을 소개한다. 이 이동로봇은 바닥 위에 설치된 선을 따라가도록 되어있다. 그리고 3개의 근접센서로부터 정보가 입력된다. 이러한 획득된 정보를 자율 주행을 위하여 퍼지로 제어하였다. 그러므로 현존하는 시스템과는 달리, 열악한 환경 조건하에서도 높은 신뢰성을 보증하고, 라인의 유지 보수를 낮은 비용으로 쉽게 설치할 수 있다. 이 자율이동로봇의 이용은 공장이나 병원 내의 물류자동화를 실현시키고, 사무실 내에서 서류배달 등의 여러분야에 응용되어 질 수 있다.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.134-143
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• 2010

We studied the hydrogen-bonded $TlH_2PO_4$ (TDP) ferroelectrics treated with the proton-beam bombardment. The TDP material was irradiated with 1-MeV proton beam at a dose of $10^{15}/cm^2$. In order to analyze the hydrogen environment in TDP, we carried out the $^1H$ high resolution nuclear magnetic resonance (NMR) - i.e., Combined Rotation And Multiple Pulse Spectroscopy (CRAMPS) measurement. The isotropic chemical shift of hydrogen indicates its displacive property is related to the $PO_4$ lattice deformation which occurs throughout the antiferroelectric-, the ferroelastic- and the paraelastic-phase transitions. The temperature dependence of $\sigma_{iso}$ reveals the electronic charge redistribution is induced by the proton-beam irradiation and the elastic property.

• 품질경영학회지
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• 제42권4호
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• pp.701-716
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• 2014

Purpose: In the paper, I studied success factors and measures for win-win quality management for boosting corporate competitiveness through the achievement of high quality. Methods: As such, to that end, data of companies' win-win quality management activities and Cooperation performance were gathered. Also, I had a literature review and working staffs'opinions were gathered to develop items related to trade dependence, quality cooperation, and mutual trust and cooperation. To develop the questionnaire, sufficient literature survey was conducted, and advice was sought from experts of manufacturing companies which practice Win-Win Cooperation. Results: Based on these previous researches and analysis by structural equation modeling, among trade dependence factors, overall, other factors except financial dependence and some detailed factors were found to have a relatively significant influence relation. Conclusion: The findings of this study suggest that if individual organizations can construct an effective quality improvement system and positively pursue win-win activities, it will contribute greatly to achieving high quality and improving financial performance. However, given the time and regional limits of this study, more in-depth studies need to be conducted on measures for boosting quality competitiveness through Win-Win Cooperation.