• 한국철도학회논문집
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• 제8권3호
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• pp.260-266
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• 2005

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The lift-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Korean Journal of Radiology
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• 제22권6호
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• pp.983-993
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• 2021

Objective: To investigate the image quality of ultralow-dose CT (ULDCT) of the chest reconstructed using a cycle-consistent generative adversarial network (CycleGAN)-based deep learning method in the evaluation of pulmonary tuberculosis. Materials and Methods: Between June 2019 and November 2019, 103 patients (mean age, 40.8 ± 13.6 years; 61 men and 42 women) with pulmonary tuberculosis were prospectively enrolled to undergo standard-dose CT (120 kVp with automated exposure control), followed immediately by ULDCT (80 kVp and 10 mAs). The images of the two successive scans were used to train the CycleGAN framework for image-to-image translation. The denoising efficacy of the CycleGAN algorithm was compared with that of hybrid and model-based iterative reconstruction. Repeated-measures analysis of variance and Wilcoxon signed-rank test were performed to compare the objective measurements and the subjective image quality scores, respectively. Results: With the optimized CycleGAN denoising model, using the ULDCT images as input, the peak signal-to-noise ratio and structural similarity index improved by 2.0 dB and 0.21, respectively. The CycleGAN-generated denoised ULDCT images typically provided satisfactory image quality for optimal visibility of anatomic structures and pathological findings, with a lower level of image noise (mean ± standard deviation [SD], 19.5 ± 3.0 Hounsfield unit [HU]) than that of the hybrid (66.3 ± 10.5 HU, p < 0.001) and a similar noise level to model-based iterative reconstruction (19.6 ± 2.6 HU, p > 0.908). The CycleGAN-generated images showed the highest contrast-to-noise ratios for the pulmonary lesions, followed by the model-based and hybrid iterative reconstruction. The mean effective radiation dose of ULDCT was 0.12 mSv with a mean 93.9% reduction compared to standard-dose CT. Conclusion: The optimized CycleGAN technique may allow the synthesis of diagnostically acceptable images from ULDCT of the chest for the evaluation of pulmonary tuberculosis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1056-1061
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• 2001

This paper describes the evaluation of noise influence of residental and boundary areas from power plant noise sources of 1200MW combined cycle power plant. Noise assessments are carried out by based on the ISO 3744, ISO 9613-1 and ISO 9613-2 to predict the noise distribution to satisfy the recommended noise level at specific locations and to calculate properly the octave noise power of main noise sources such as power transformers. air-intakes, stacks.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.47-48
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• 2022

In Korea, construction and development has been continued rapidly since the 1970s, and the reconstruction and renovation market has recently been activated to improve old buildings. Most of the environmental evaluation of reconstruction and renovation projects is focused on the use of operating energy, and It is necessary to analyze carbon emissions throughout the life cycle for a comprehensive evaluation of reconstruction and remodeling projects. Therefore, this study quantitatively predicted carbon emissions from reconstruction and renovation based on ISO 14040s through case analysis for the purpose of evaluating the carbon emissions of renovated buildings from the perspective of the whole life cycle. In additional, the amount of carbon savings of each was analyzed through comparison with existing building.

• 한국추진공학회지
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• 제26권4호
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• pp.64-71
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• 2022

개량된 성능의 상단엔진 개발을 위해 다단연소 사이클 액체로켓엔진의 연구가 진행 중이다. 재점화 기술을 개발하기 위한 수류시험, 점화시험, 연소시험을 계획하여 수행하였다. 재점화 시 터보펌프에서 캐비테이션 현상을 발생시킬 수 있는 연료라인으로의 퍼지가스 유입문제를 해결하기 위해, 각 단계의 시험결과를 분석하였다. 분석결과를 바탕으로 기포제거 밸브의 작동, 퍼지밸브와 엔진 연료밸브의 열림 중첩시간 줄임을 통해 퍼지가스 유입문제를 해결하였다. 이를 바탕으로 재점화 연소시험을 성공적으로 수행하였다.

• 한국BIM학회 논문집
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• 제5권2호
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• pp.34-45
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• 2015

As buildings become larger and more complicated, construction costs have increased with a considerable effect on buildings' Life Cycle Cost (LCC). However, there has been little consideration on economic aspects in the selection of construction materials due to limited information on the materials and dependency in architects' experience and inefficiency in cost estimation, causing design changes, increase in maintenance cost, difficulty in budgeting, and decrease in building performance. To solve these problems, this study proposed a BIM-based material selection model which reflects the comprehensive economic efficiency of building materials. Our cost prediction model can estimates the material-related cost during the entire building life cycle. Furthermore, we implemented the proposed model in connection with BIM, which can analyze and compare LCC by material. Through the validation of the model, we could confirm the necessity of LCC-based material selection in comparison with the conventional cost-centered material selection.

• 방사성폐기물학회지
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• 제17권1호
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• pp.47-58
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• 2019

The paper presents the results of a multi-criteria comparative evaluation of 12 feasible Russian nuclear energy deployment scenarios with thermal and fast reactors in a closed nuclear fuel cycle. The comparative evaluation was performed based on 6 performance indicators and 5 different MCDA methods (Simple Scoring Model, MAVT / MAUT, AHP, TOPSIS, PROMETHEE) in accordance with the recommendations elaborated by the IAEA/INPRO section. It is shown that the use of different MCDA methods to compare the nuclear energy deployment scenarios, despite some differences in the rankings, leads to well-coordinated and similar results. Taking into account the uncertainties in the weights within a multi-attribute model, it was possible to rank the scenarios in the absence of information regarding the relative importance of performance indicators and determine the preference probability for a certain nuclear energy deployment scenario. Based on the results of the uncertainty/sensitivity analysis and additional analysis of alternatives as well as the whole set of graphical and attribute data, it was possible to identify the most promising nuclear energy deployment scenario under the assumptions made.

• 한국프랜차이즈경영연구
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• 제12권2호
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• pp.23-33
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• 2021

Purpose: The purpose of this study is to provide basic data such as development of sustainable support policies and performance management evaluation to support sustainable management of domestic franchises by deriving the sustainable growth cycle of domestic franchises. Research design, data, and methodology: This study is based on systematic review study. We combined search terms such as "Start-up", "Sustainability" and "Success" with four databases, RISS, KISS, e-article and DBpia and searched a total of 1,219 articles published by April 21, 2021. In the process, 35 studies were selected and analyzed after an expert review, excluding documents whose overlapping documents, gray zones (e.g., reports, conference presentations, etc.), degree papers, foreign language literature, and dependent variables were not related to the Sustainability factors. Using ERIS model, which is applied to research on the results of startup, and the franchise's growth cycle, which reflects the growth stage of franchises, we analyzed the factors behind the sustainability of franchise. Result: The results of the study are as follows. First, research on the sustainability of franchise has continued since 2009 in Korea, and has been conducted in various fields such as social welfare in addition to venture, start-up and management. Second, sustainability factors of franchise were analyzed from the ERIS performance model indicating the performance of venture, and the 68 subfactors were derived. Third, it is confirmed that there are important factors that affect the sustainable growth of franchise startups in each franchise's growth cycle. Conclusions: It is significant that through this study, we provided better understanding of the factors that sustain sustainability of franchises, policy suggestions, and presented the direction of future study. Theoretical suggestion is that the main reason for the continuous growth of franchise in each domestic franchise is based on the ERIS performance model. The practical implication is that the headquarters and Franchisor can use it to establish and evaluate performance indicators based on the business growth cycle. The results of this study are expected to be used as basic data for development and performance management evaluation of franchise start-up support policies to support the sustainable management of domestic franchises.

• 조명전기설비학회논문지
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• 제18권6호
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• pp.191-196
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• 2004

이 논문에서는 버스시스템의 성능 평가를 위한 순환시간의 계측방법이 제안 되었다. 센서와 엑튜에이터가 주를 이루는 생산시스템에서 순환시간은 버스시스뎀의 성능평가의 중요한 파라미터이다. 순환시간을 계측하기 위하여 제안된 방법은 간단한 알고리즘의 구성에 기반을 두었으나 주변기기나 PLC의 내부에 존재하는 지연요소들을 고려 해야만 한다. 계측결과의 개선을 기하기 위해 시험방법은 최적, 최저의 경우로 나누어 이에 대응되는 파라미터를 구성하여 값을 설정한다. 수학적인 모델을 기반으로 필드버스 시스템의 순환시간에 대한 계측을 통해 제안된 방법이 효율적임을 입증하였다. 그 결과로서 제안된 방법의 간편성과 편리함으로 인해 순환시간의 측정에 요구되는 엔지니어링 비용과 시간을 절감할 수 있었다.

• 전기학회논문지
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• 제60권11호
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• pp.1993-1999
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• 2011

Today, the power utilities is setting on the slow load growth and the aging of power equipment, and then could spend the efforts on the stability of system performance. Asset management may be defined as the process of maximizing corporate profit by maximizing performance and minimizing cost over the entire life cycle of power equipment. Therefore, asset management is great way to fulfill the economic investment and the stability of system performance. This paper presents the application of effective asset managem ent from an economic perspective. A proposed method is considering the life cycle analysis using life cycle cost methodology for hydro-generator during the total life cycle. The life cycle cost methodology include a way to calculating maintenance and operating costs. The proposed method will be expected to play an important role in investment decision making considering economic evaluation.