• 한국자동차공학회논문집
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• 제13권3호
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• pp.96-101
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• 2005

Cogeneration is an energy conversion process, where electricity and useful heat are produced simultaneously in one process. Also, carbon dioxide emissions can be reduced as well. The cogeneration process may be based on the use of steam, gas turbines or combustion engines. However, there have been few models with an output of less than 100 kilowatt. In the present study, a spark ignited gas engine with generation output of 10 kilowatts was developed for micro cogeneration package. The gas engine shows 29.2$\%$ of thermal efficiency under Stoichiometric combustion and 33.6$\%$ of thermal efficiency under lean combustion. NOx emission shows less than 10ppm at 13$\%$ oxygen under stoichiometric combustion and about 100ppm at 13$\%$ oxygen under lean combustion.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.8-16
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• 1999

In this study, a new type of laser-induced ignition using a conical cavity has been developed to utilize all the available incident laser energy. In the method, it is possibile to ignite combustible methane/air mixtures by directing a laser beam of a constant small diameter into a small conical cavity, without focusing the laser beam. Shadow graphs for the early stage of combustion process show that a hot gas jet is ejected from the cavity, especially with lean mixture. After a very show time, the hot gas jet finishes issuing and the flame behavior is quite similar to flame propagation initiated by a conventional spark ignition. The combustion process using the new method exhibits more rapid pressure increase and a higher maximum pressure rise than that of the center ignition using laser-induced spark, with significant decrease in the combustion time. Also, the new ignition method is numerically modeled to simulate the flame kernel development and subsequent combustion process using the KIVA-IIcode. The calculated results show satisfactory agreement with experimental results.

• Agricultural and Biosystems Engineering
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• 제4권1호
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• pp.16-21
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• 2003

In the agricultural field, a machine vision system has been widely used to automate most inspection processes especially in quality grading. Though machine vision system was very effective in quantifying geometrical quality factors, it had a deficiency in quantifying color information. This study was conducted to evaluate color of beef using machine vision system. Though measuring color of a beef using machine vision system had an advantage of covering whole lean tissue area at a time compared to a colorimeter, it revealed the problem of sensitivity depending on the system components such as types of camera, lighting conditions, and so on. The effect of color balancing control of a camera was investigated and multi-layer BP neural network based color calibration process was developed. Color calibration network model was trained using reference color patches and showed the high correlation with L*a*b* coordinates of a colorimeter. The proposed calibration process showed the successful adaptability to various measurement environments such as different types of cameras and light sources. Compared results with the proposed calibration process and MLR based calibration were also presented. Color calibration network was also successfully applied to measure the color of the beef. However, it was suggested that reflectance properties of reference materials for calibration and test materials should be considered to achieve more accurate color measurement.

• Journal of Construction Engineering and Project Management
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• 제6권1호
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• pp.11-19
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• 2016

Most of the Indian contractors are not well equipped to handle the growing demand of infrastructure development; hence construction projects frequently run in to time and cost overruns, disputes and quality issues. This study aims to improve the construction industry in India by implementing lean principles to eliminate non-value adding activities (wastes). The purpose of this study is to 1) identify the wastes and their sources affecting the construction process, and 2) to identify problems and document lessons by applying a Last Planner System (LPS) to a sample project. First, the researchers identified that Delays, Rework, and Interruptions were the most critical wastes affecting the construction process and Poor management control, Poor Planning and Shortage of Resources were the major sources of the above mentioned wastes. Second, the researchers report the Percent of Planned Complete (PPC) analysis results and experienced problems after implementation of LPS at the sample project. It was observed that much more improvement could have been achieved if there was consensus between the owners and the contractor on the implementation of the LPS in its entirety. Some of the problems experienced in the implementation of the LPS like lack of scheduling, resource and material shortage were found to be similar to those in developed countries.

• 벤처창업연구
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• 제7권1호
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• pp.189-206
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• 2012

최근 탈공업화와 산업의 서비스화로 서비스산업 뿐만 아니라 제조업 등 2차 산업에 있어서의 서비스 비중은 나날이 커지고 있어 금융 및 서비스업 그리고 제조업의 사무 서비스부문의 경영혁신이 절실한 실정이다. 급변하는 경영환경에 적극적으로 대처하기 위해 기업들은 여러 가지 경영혁신 방법을 도입하고 있다. 특히, 우리나라의 경우에는 선진기업의 혁신활동에 대해서는 유행적으로 도입하여 적용하고 있는 실정이다. 이러한 측면에서 1990년대 중반부터 6시그마(Six Sigma)가 도입되어 10년 이상을 경영혁신활동의 대명사가 되어 활발하게 추진하여 왔다. 그러나 6시그마는 도입 초기의 기대에 미치지 못하고 있다는 지적과 최근 들어 한국기업이 금융시장의 불안, 경기 침체 및 중국 등 후발 국가로부터 많은 도전을 받고 있는 상황에서 '린(Lean)' 이라는 혁신활동이 국내에 소개되고, 도요타자동차의 성장으로 린의 모태인 도요타 생산방식(Toyota Production System, TPS)이 다시 각광을 받으면서 린에 대한 관심이 집중되고 있다. 본 연구에서는 우선 린 경영의 진화과정 및 특징의 기존 연구를 고찰하고 제조부문과 사무 서비스부문과의 차이점을 비교 연구하였다. 다음으로 우리나라 기업의 혁신 담당자를 대상으로 설문조사를 실시한 다음, 사무 서비스부문에서의 린 적용에 대한 실행 모델을 제시하고 적용하였다. 그 동안 제조부문에서는 린에 대한 성공사례도 많고 이와 관련된 연구 또한 많이 수행되어 왔다. 그러나 사무 서비스부문에서의 린 적용에 대한 연구는 아직 그 활용이 초기 단계로 관련 연구가 많지 않은 상태이며 실증연구는 거의 찾아보기 어려운 실정이다. 본 연구는 린 경영의 이론적 고찰을 바탕으로 린 경영의 성공요인을 도출하고 기업에서 실질적으로 린을 추진하고 있는 추진자들을 대상으로 실증 연구를 하였다. 이는 린 경영이 최근 우리나라에 도입되고 있는 상황에서 어느 정도 향도로서의 역할을 할 수 있을 것으로 판단한다. 본 연구는 린을 적용하고 있는 기업 또는 경쟁력 강화를 위해 새롭게 린 경영 도입을 검토하고 있는 기업 및 동 주제에 대한 연구자들에 대하여 사무 서비스부문에서 효율적이고 성공적인 린 경영 추진을 위한 올바른 방향을 제시했다는데 의의가 있다 하겠다.

• Geomechanics and Engineering
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• 제21권5호
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• pp.413-422
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• 2020

The choice of eco-friendly materials for ground improvement is a necessary way forward for sustainable development. Adapting naturally available biopolymers will render the process of soil stabilization carbon neutral. An attempt has been made to use β-glucan, a natural biopolymer for the stabilization of lean clay as a sustainable alternative with specific emphasis on comprehending the effect of confining stresses on lean clay through triaxial compression tests. A sequence of laboratory experiments was performed to examine the various physical and mechanical characteristics of β-glucan treated soil (BGTS). Micro-analysis through micrographs were used to understand the strengthening mechanism. Results of the study show that the deviatoric stress of 2% BGTS is 12 times higher than untreated soil (UTS). The micrographs from Scanning Electron Microscopy (SEM) and the results of the Nitrogen-based Brunauer Emmett Teller (N₂-BET) analysis confirm the formation of new cementitious fibres and hydrogels within the soil matrix that tends to weld soil particles and reduce the pore spaces leading to an increase in strength. Hydraulic conductivity (HC) and compressibility reduced significantly with the biopolymer content and curing period. Results emphases that β-glucan is an efficient and sustainable alternative to the traditional stabilizers like cement, lime or bitumen.

• 대한안전경영과학회지
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• 제17권1호
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• pp.321-335
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• 2015

This study introduces the methods to apply and develop the integrated Cost of Quality (COQ) and Time-Driven Activity-Based Costing (TDABC) model for seeking not only quality improvement but also reduction of overhead cost. Inefficient and uneconomical COQ activities can be identified by using time driver which also maximizes the quality improvement for Prevention-Appraisal- Failure (PAF) quality costs. In contrast, reduction of the indirect cost of unused capacity resource using Quality Cost Capacity Ratio (QCCR) of TDABC minimizes overhead cost for COQ activities. In addition, linkage between Overall Equipment Effective (OEE) and Time Driver develops the integrated system of Total Productive Maintenance (TPM) and TDABC model. Lean OEE maximizes when an Unused Time (UT) of TDABC that are TPM losses and lean wastes reduces whereas the TPM Cost Capacity Ratio (TCCR) of TDABC minimizes indirect cost for non-value added TPM activities. Numerical examples are derived to better understand the proposed COQ/TDABC model and TPM/TDABC model from this paper. From the proposed model, process mapping and time driver of TDABC are known to lessen indirect cost from general ledger of comprehensive income statement with a better quality innovation and improvement of equipment.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.892-898
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• 2007

본 연구는 중소(지방)건설업체의 효율적인 공정관리와 국내 건설 산업의 성과관리를 위한 시스템 구축을 목적으로 한다. 린 건설의 공정관리 프로세스를 탑재한 시스템은 Web 2.0 플랫폼을 기반으로 프로젝트에 참여한 수많은 원도급업체와 협력업체의 클러스터를 생성하여 상호 유기적인 공정관리를 가능하게 할 것이다. 또한 프로젝트 진행 중 발생되는 수많은 데이터를 수집/축적하여 프로젝트가 진행 중이거나 종료 된 후 이를 분석하여 프로젝트의 성과관리에 대한 비교가 가능 할 것이다. 이러한 성과관리 사례들은 차후 실행되는 유사한 프로젝트의 공정계획에도 도움이 될 것이다. 본 연구의 기대효과는 Web을 통한 공정관리로 인해 국내 중소(지방)건설업체가 느끼는 복잡한 공정관리 및 시스템 구축에 따른 부담감을 조금이나마 덜어 줄 것이며, 데이터베이스에 축적되는 방대한 양의 신뢰도 높은 데이터로 보다 정확한 성과관리를 할 것으로 기대된다. 그리고 더 나아가 공정관리뿐만 아니라 설계, 감리, CM 등 폭 넓은 데이터베이스 구축을 통해 건설산업의 경쟁력 향상에도 기여 할 것이다.

• KEPCO Journal on Electric Power and Energy
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• 제4권1호
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• pp.33-38
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• 2018

This study applied upgrades to the processes of a 10 MW wet amine $CO_2$ capture pilot plant and conducted performance evaluation. The 10 MW $CO_2$ Capture Pilot Plant is a facility that applies 1/50 of the combustion flue gas produced from a 500 MW coal-fired power plant, and is capable of capturing up to 200 tons of $CO_2$. This study aimed to quantitatively measure efficiency improvements of post-combustion $CO_2$ capture facilities resulting from process upgrades to propose reliable data for the first time in Korea. The key components of the process upgrades involve absorber intercooling, lean/rich amine exchanger efficiency improvements, reboiler steam TVR (Thermal Vapor Recompression), and lean amine MVR (Mechanical Vapor Recompression). The components were sequentially applied to test the energy reduction effect of each component. In addition, the performance evaluation was conducted with the absorber $CO_2$ removal efficiency maintained at the performance evaluation standard value proposed by the IEA-GHG ($CO_2$ removal rate: 90%). The absorbent used in the study was the highly efficient KoSol-5 that was developed by KEPCO (Korea Electric Power Corporation). From the performance evaluation results, it was found that the steam consumption (regeneration energy) for the regeneration of the absorbent decreased by $0.38GJ/tonCO_2$ after applying the process upgrades: from $2.93GJ/ton\;CO_2$ to $2.55GJ/tonCO_2$. This study confirmed the excellent performance of the post-combustion wet $CO_2$ capture process developed by KEPCO Research Institute (KEPRI) within KEPCO, and the process upgrades validated in this study are expected to substantially reduce $CO_2$ capture costs when applied in demonstration $CO_2$ capture plants.

• Journal of Construction Engineering and Project Management
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• 제4권2호
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• pp.12-22
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• 2014

Over the last decade, Saudi Arabia has experienced significant economic increases as evidenced by the 30% growth in its gross domestic product; furthermore, the construction industry has increased 10% in the same time period. Due to this significant growth, the construction industry is encountering issues related to construction quality resulting in significant waste and associated environmental impacts. In this research, we applied our previously developed framework that integrates three different methods-Lean, Green, and Six-sigma - to a residential construction complex in Saudi Arabia. Our aim of this case study was to explore the application of the framework in practice to glean quantitative results and further validate the framework. In the case study, we used the developed framework to identify a significant issue related to quality and delays - final completion of 53 residential units was delayed because of failed exterior buildings surfaces. We then used the framework to define the causes behind the defects via a field investigation of the 53 units. Of the defect, construction execution was responsible for 43% of the defect, 31% untrained workers, 19% unfavorable construction weather condition, with 7% accounting for other issues. A procedure was developed in concert with the construction manager and overall developer reducing the amount of rework and waste causes revealed by the field examination and the framework. Although two steps were added to the original construction process to overcome waste causes, still save a lot of resources and reduces environmental impact. In summary, we found that the Lean, Green, Six-sigma framework increased productivity, quality, and reduced waste.