• 한국건설관리학회논문집
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• 제17권3호
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• pp.116-124
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• 2016

건설현장의 주요 작업인 토공사의 경우, 토공 건설장비를 운용하는 개별 작업자에 의해서 작업의 효율성이 좌우되기 때문에 개별 작업자의 숙련도가 전체적인 공사일정에 큰 영향을 미칠 수 있다. 건설현장에는 그 특성상 현장 내 설치된 구조물이나 장비 혹은 움직이는 작업자들이나 장비 등으로 인해 시야가 가려져서 발생하게 되는 비가시 영역이 필연적으로 존재한다. 이와 같은 작업 관련 시각정보의 부재는 작업자가 건설장비를 효율적으로 운용하는데 있어서 결정적인 저해요소가 된다. 증강현실(AR, Augmented Reality)은 현실세계에 가상물체를 중첩시켜 보여주는 컴퓨터 기술이다. 이 기술의 특성을 이용하면 토공사를 수행하는 과정에서의 시각정보 부재 문제를 해결할 수 있고 이를 통한 건설장비의 작업 효율성 향상이 가능하다. 본 연구의 목적은 이러한 토공사에서의 필요 시각정보를 도출하기 위한 작업-시각정보 맵을 제시하고 굴삭기의 작업들 중 AR기술을 적용하기에 적합한 것을 찾아내는 것이다. 연구의 대상이 되는 건설장비는 굴삭기로 한정하였다. 작업-시각정보 맵은 굴삭기 토공작업의 문제점과 그 문제점을 해결하는데 필요한 시각정보를 기반으로 하여 작성되었다. 이 맵으로부터 굴삭기의 작업 효율성을 향상시킬 수 있고, AR기술을 적용하기에도 적합한 4가지 필요 시각정보가 도출되었다. 연구결과를 바탕으로 하여 추후 건설장비 AR 네비게이터 시스템을 더욱 효과적으로 개발할 수 있을 것이라 기대한다.

• Journal of Power Electronics
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• 제18권4호
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• pp.975-984
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• 2018

This work presents a high efficiency phase shifted full bridge (PSFB) DC-DC converter for use in the second stage of a battery charger for neighborhood electrical vehicle (EV) applications. In the design of the converter, Lithium-ion battery cells are preferred due to their high voltage and current rates, which provide a high power density. This requires wide range output voltage regulation for PSFB converter operation. In addition, the battery charger works with a light load when the battery charge voltage reaches its maximum value. The soft switching of the PSFB converter depends on the dead time optimization and load condition. As a result, the converter has to work with soft switching at a wide range output voltage and under light conditions to reach high efficiency. The operation principles of the PSFB converter for the continuous current mode (CCM) and the discontinuous current mode (DCM) are defined. The performance of the PSFB converter is analyzed in detail based on wide range output voltage and load conditions in terms of high efficiency. In order to validate performance analysis, a prototype is built with 42-54 V / 15 A output values at a 200 kHz switching frequency. The measured maximum efficiency values are obtained as 94.4% and 76.6% at full and at 2% load conditions, respectively.

• 한국유기농업학회지
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• 제22권4호
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• pp.581-591
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• 2014

This study analyze the policy efficiency of the environment-friendly farming zone program using data envelopment analysis. On analyzed results, the average policy efficiency is 0.185 and 98.3% of zones are inefficient. 97.8% of zones are in increasing returns to scales. The empirical results indicate that more work need to be done to increase the efficiency of the program.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.695-698
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• 2021

Efficiency calibration is a fundamental procedure in gamma spectrometric measurement. Experimental technique for efficiency calibration transfer in gamma spectrometer along different geometries and volumes has been developed and validated in this work. The developed technique offers simple and easy procedures to overcome several problems encountered in efficiency calibration of gamma spectrometer such as rate-related correction and different sample volumes. The validation shows that application of the developed technique has a precision of 95%.

• Journal of Computational Design and Engineering
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• 제1권2호
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• pp.140-151
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• 2014

Storing, and the loading and unloading of materials at production sites in the manufacturing sector for mass production is a critical problem that affects various aspects: the layout of the factory, line-side space, logistics, workers' work paths and ease of work, automatic procurement of components, and transfer and supply. Traditionally, the nesting problem has been an issue to improve the efficiency of raw materials; further, research into mainly 2D optimization has progressed. Also, recently, research into the expanded usage of 3D models to implement packing optimization has been actively carried out. Nevertheless, packing algorithms using 3D models are not widely used in practice, due to the large decrease in efficiency, owing to the complexity and excessive computational time. In this paper, the problem of efficiently loading and unloading freeform 3D objects into a given container has been solved, by considering the 3D form, ease of loading and unloading, and packing density. For this reason, a Group Packing Approach for workers has been developed, by using analyzed truck packing work patterns and Group Technology, which is to enhance the efficiency of storage in the manufacturing sector. Also, an algorithm for 3D packing has been developed, and implemented in a commercial 3D CAD modeling system. The 3D packing method consists of a grouping algorithm, a sequencing algorithm, an orientating algorithm, and a loading algorithm. These algorithms concern the respective aspects: the packing order, orientation decisions of parts, collision checking among parts and processing, position decisions of parts, efficiency verification, and loading and unloading simulation. Storage optimization and examination of the ease of loading and unloading are possible, and various kinds of engineering analysis, such as work performance analysis, are facilitated through the intelligent 3D packing method developed in this paper, by using the results of the 3D model.

• 산업경영시스템학회지
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• 제2권2호
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• pp.39-51
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• 1979

In introducing and applying the budget management system, the question of how to establish management structure(skelton) representing budget management responsible unit is significantly related to the degree of accuracy and analysis on the performance measurement of standard work unit. We have the following rational process of establishing performance measurement of budget management System ; 1) Standardization of work method 2) Establishment of management structure 3) Institution of budget management system. Especially, this system is based on a premise of efficiency of objectives management, it is assumed that performance measurement in the standard work unit must be enforced according to the basis and categories of performance evaluation based on the evaluating work unit. Therefore, most of all, the following three detail questions(subjects) are to be determined in order to rationalize these above principles to a maximum possible extent of performance measurement system. First, we established respective performance standard unit with respect to such detailed work unit, performance standard unit of which were accurately applicable directly from using the budget ana objectives account data and their supplementary data of the work measurement techniques. Second, by using the above mentioned question, over all evaluation and suggestion are made based on the study of the recording for each work unit development, budget management and production nit (volume of production) Third, the measurement of performance of budget management system is based on the principle of standard work unit, compared with the standard basis and actual work unit by period and activities unit and calculated percentage effectiveness according to the above procedure. and so evaluated the efficiency of performance measurement on the budget management system.

• Architectural research
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• 제15권3호
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• pp.167-174
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• 2013

Due to increasing competition of construction companies, it is required to optimize the management of construction projects and "lean" concepts are rapidly spreaded in construction industry. Steel work accounts for a large proportion in construction work, and a variety of attempts to efficiently perform steel work has currently made. And since rebar (Engineer-to-Order) can be engineered through design once order is placed, it gives the great impact on construction, thus, entire management is required. The purpose of this study is to present the method to increase the efficiency of field processing method of steel work in terms of lean construction. Once we examine process of steel work and identify the flow, we would like to analyze which processes should be improved through value analysis approach and present the improvement plans. Also, this study examines cases of field processing and factory processing, and it identifies the waste factors in the procurement process. Finally, this study would like to present the result of analysis from the perspectives of value. The rebar delivery process is divided into several steps and the duration of every step is surveyed. Using duration data, VAT (Value added time) can be calculated for analyzing the efficiency of the process.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.483-486
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• 2006

건설 프로젝트에서 VE는 예산절감 및 품질을 향상시킬 수 있는 체계적인 방법이며 최근 건설VE 업무의 적용범위가 확대됨에 따라 그 중요성이 부각되고 있다. 따라서 VE 업무를 체계적이고 효율적으로 수행할 수 있는 방법에 관한 연구가 요구된다. 이에 본 연구에서는 현행 건설VE 업무 진행과정상의 문제점을 분석하여 업무 능률을 효율화할 수 있는 모델을 제안하였다. 제안 모델은 발주자 및 사용자의 요구항목을 체계적으로 반영하여 초기 VE 업무의 접근 방향 및 기준 설정을 가능하게 할 것이다. 따라서 후속적으로 진행되는 분석단계의 기능분석 및 아이디어 창출 업무의 효율성을 증대시켜 성공적인 VE 성과를 도출 가능하게 할 것이다.

• 한국안전학회지
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• 제17권3호
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• pp.96-101
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• 2002

The object of risk assesment is to prevent the accident from arising. The main reason for risk assesment of construction work is to determine priority order of improvement plan about risky work. Formwork is a complicated process that determines the total duration of apartment construction, and occupies 10∼15% of total construction expense, and 17% of serious accidents occur during formwork. So, formwork occupies very importment roles in work sites, economical efficiency and safety. We need to identify the work type with a high risk of accidents, and to establish suitable safety counterplan and implement intensive safety management.

• 대한인간공학회지
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• 제29권4호
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• pp.495-503
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• 2010

The packing and sorting processes of grape are required repetitive movements to need considerable physical load for a long time. And thereby, there is strong possibility to cause musculoskeletal disorders. In this study, ergonomically designed convenience equipments of worktable and handcart are introduced for improvement of the working movements and less physical load to increase the work efficiency. For objective analysis of the movements and the workload between the ones before and after the improvement, we measured heart rate, OWAS, RULA, REBA, LMM, moving Line and work time. Also, we used a checklist of physical fatigue regions to confirm the subjective evaluation of physical load of workers. As the result of study, it showed lower heart rate, value of Working Postures (OWAS, RULA, REBA) and LMM in the work after introduction of those convenient equipments than the work of before the introduction. The work time and moving Line were shortened and the number of grape boxes packed within the same work time was increased, too. Also the overall load as the subjective evaluation was reduced.