• International Journal of Naval Architecture and Ocean Engineering
• /
• 제13권1호
• /
• pp.102-114
• /
• 2021

Biofouling represents an important problem in the shipping industry since it causes the increase in surface roughness. The most of ships in the current world fleet do not have good coating condition which represents an important problem due to strict rules regarding ship energy efficiency. Therefore, the importance of the control and management of the hull and propeller fouling is highlighted by the International Maritime Organization and the maintenance schedule optimization became valuable energy saving measure. For adequate implementation of this measure, the accurate prediction of the effects of biofouling on the hydrodynamic characteristics is required. Although computational fluid dynamics approach, based on the modified wall function approach, has imposed itself as one of the most promising tools for this prediction, it requires significant computational time. However, during the maintenance schedule optimization, it is important to rapidly predict the effect of biofouling on the ship hydrodynamic performance. In this paper, the effect of biofilm on the ship hydrodynamic performance is studied using the proposed performance prediction method for three merchant ships. The applicability of this method in the assessment of the effect of biofilm on the ship hydrodynamic performance is demonstrated by comparison of the obtained results using the proposed performance prediction method and computational fluid dynamics approach. The comparison has shown that the highest relative deviation is lower than 4.2% for all propulsion characteristics, lower than 1.5% for propeller rotation rate and lower than 5.2% for delivered power. Thus, a practical tool for the estimation of the effect of biofouling with lower fouling severity on the ship hydrodynamic performance is developed.

• 터널과지하공간
• /
• 제32권3호
• /
• pp.173-193
• /
• 2022

본 연구에서는 GMG (Global Mining Guidelines Group)에서 개발한 광업 분야 가이드라인을 중심으로 스마트 마이닝 기술 국제 표준화 동향을 분석하였다. GMG는 글로벌 광업 커뮤니티를 하나로 묶는 비영리 단체이며, 광업의 안전과 혁신, 지속가능성을 제고시키기 위한 목적으로 설립되었다. 현재 GMG의 실무그룹은 인공지능, 자산관리, 자율 채광, 사이버 보안, 데이터 접근 및 사용/상호 운용성, 전기화, 광물 처리, 지하 채광, 지속가능성 실무그룹으로 구성되어 있다. 스마트 마이닝 기술과 관련한 가이드라인 개발 프로젝트는 인공지능, 자율 채광, 사이버 보안, 데이터 접근 및 사용/상호운용성, 지하 채광 실무그룹에서 진행되고 있다. 2022년 4월 현재 8종의 스마트 마이닝 관련 가이드라인은 사전 착수, 착수, 가이드라인 정의, 콘텐츠 생성, 기술 수정, 레이아웃 및 최종 검토, 투표 과정을 거쳐 출판되었다. GMG에서 출판한 가이드라인은 국내 스마트 마이닝 기술 표준 개발에 있어 중요한 참고 자료가 될 수 있을 것이라 판단된다.

• 한국의류산업학회지
• /
• 제24권2호
• /
• pp.206-216
• /
• 2022

This study sought to examine the sustainability criteria found in the global sourcing practices of global fashion retailers. Sustainable supply chain management, with a particular focus on the sustainability criteria of global sourcing, was analyzed. This qualitative study was based on a focus group interview and corporate social responsibility (CSR) annual reports. Eight master categories, 18 middle categories, and 37 bottom categories were extracted. The key categories and their middle categories were as follows: (1) Social compliance (working conditions, employment, safety); (2) Environment concerns (environmental pollution management, eco-friendly production, supply chain environment); (3) Energy efficiency (energy saving program, store environment); (4) Consumer protection (restricted substances management, consumer product safety improvement); (5) Management system (code of conduct, triangle audit system); (6) Community social activities (local community service, voluntary activities, charitable activities); (7) External stakeholder engagement (media & non-governmental organization management, maintenance of relationship with local authority); (8) Brand protection (respect for companies' intellectual property). The findings of this study offer academically significant insights into the sustainability criteria that can be encountered by companies under diverse global sourcing scenarios, revealing that global sourcing by fashion retailers is not merely a means of reducing costs, but a way of generating new jobs and making a social contribution to developing countries. The study's findings also have practical significance, offering guidelines for general CSR activities in the global sourcing process.

• Animal Bioscience
• /
• 제37권3호
• /
• pp.405-418
• /
• 2024

In recent years, there has been a growing argument attributing the primary cause of global climate change to livestock industry, which has led to the perception that the livestock industry is synonymous with greenhouse gas (GHG) emissions. However, a closer examination of the global GHG emission by sector reveals that the energy sector is responsible for the majority, accounting for 76.2% of the total, while agriculture contributes 11.9%. According to data from the Food and Agriculture Organization of the United Nations (FAO), the total GHG emissions associate with the livestock supply chain amount to 14.5%. Within this, emissions from direct sources, such as enteric fermentation and livestock manure treatment, which are not part of the front and rear industries, represent only 7%. Although it is true that the increase in meat consumption driven by global population growth and rising incomes, has contributed to higher methane (CH₄) emissions resulting from enteric fermentation in ruminant animals, categorizing the livestock industry as the primary source of GHG emissions oversimplifies a complex issue and disregards objective data. Therefore, it may be a misleading to solely focus on the livestock sector without addressing the significant emissions from the energy sector, which is the largest contributor to GHG emissions. The top priority should be the objective and accurate measurement of GHG emissions, followed by the development and implementation of suitable reduction policies for each industrial sector with significant GHG emissions contributions.

• 대한공업교육학회지
• /
• 제38권1호
• /
• pp.29-48
• /
• 2013

본 연구의 목적은 기술 가정교과 '에너지와 수송기술' 단원에서 활용할 STEAM 교육의 바람직한 사례를 제공하는데 있다. STEAM 통합 교육에 의한 활동을 통해 중학생들은 통합적 접근으로 학습하였고, 제작 과정을 통해 다양한 형태로 적용하고 표현하는 기회를 갖게 되었다. 이러한 목적을 달성하기 위한 과정을 통해 얻은 결론은 다음과 같다. 첫째, 기술 가정교과 '에너지와 수송기술' 단원에서 활용할 STEAM 프로그램 개발을 위한 절차 모형은 준비, 개발, 검증, 실행, 평가의 5단계로 제시하였다. 준비단계는 요구 분석, STEAM 프로그램 주제 선정, STEAM 프로그램 교육과정 분석, STEAM 프로그램 학습내용 선정 및 조직으로 구성되어 있으며, 개발단계는 수업과정안, 멀티미디어 수업자료, 학습 활동지 개발, 활동지 답안 개발로 제시하였다. 검증단계는 전문가에 의한 타당도 검증을 실시하고, 실행단계는 중학생을 대상으로 개발된 프로그램을 현장 실행하며, 평가단계는 학습자와 수업자의 평가를 받아 수정 및 보완한다. 둘째, STEAM 프로그램은 STEAM 프로그램 요약도, 수업과정안, 멀티미디어 수업자료, 학습 활동지, 활동지 답안 등을 개발하였고, 전문가 검증을 통해 타당성을 확보한 후 수정, 보완하여 STEM 프로그램을 실제 수업에 적용하였다. 셋째, 개발된 STEAM 프로그램의 학습자 평가 결과를 보면, 전체 문항의 평균이 5점 만점중 4.00점으로 프로그램에 대해 만족도가 높음을 알 수 있었다. 수업자 평가 결과도 개발된 STEAM 프로그램을 매우 효과적으로 평가하였다. 학습자와 수업자의 의견을 수렴하여 최종적으로 프로그램을 평가하고 완성하였다.

• Nuclear Engineering and Technology
• /
• 제50권3호
• /
• pp.356-367
• /
• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• Nuclear Engineering and Technology
• /
• 제54권2호
• /
• pp.479-485
• /
• 2022

At the Korea Institute of Radiological and Medical Sciences, physical human phantoms were developed to evaluate various radiation protection quantities, based on the mesh-type reference computational phantoms of the International Commission on Radiological Protection. The physical human phantoms were fabricated such that a radiophotoluminescent glass dosimeter (RPLGD) with a Tin filter, namely GD-352M, could be inserted into them. A Tin filter is used to eliminate the overestimated signals in low-energy photons below 100 keV. The measurement uncertainty of the RPLGD reader system based on GD-352M should be analyzed for obtaining reliable protection quantities before using it for practical applications. Generally, the measurement uncertainty of RPLGD systems without Tin filters is analyzed for quality assurance of radiotherapy units using a high-energy photon beam. However, in this study, the measurement uncertainty of GD-352M was analyzed for evaluating the protection quantities. The measurement uncertainty factors in the RPLGD include the reference irradiation, regression curve, reproducibility, uniformity, energy dependence, and angular dependence, as described by the International Organization for Standardization (ISO). These factors were calculated using the Guide to the Expression of Uncertainty in Measurement method, applying ISO/ASTM standards 51261(2013), 51707(2015), and SS-ISO 22127(2019). The measurement uncertainties of the RPLGD reader system with a coverage factor of k = 2 were calculated to be 9.26% from 0.005 to 1 Gy and 8.16% from 1 to 10 Gy. A blind test was conducted to validate the RPLGD reader system, which demonstrated that the readout doses included blind doses of 0.1, 1, 2, and 5 Gy. Overall, the E_n values were considered satisfactory.

• 임상간호연구
• /
• 제22권3호
• /
• pp.314-326
• /
• 2016

Purpose: The purpose of this study was to understand the experience of emotional labor of clinical nurses in medical institutes. Methods: A total of 26 nurses from 11 hospitals participated in the study. Six focus groups were organized and 4 to 5 nurses took part in each group. The compositional factors of groups included clinical experience, age, gender, work place and position. Data collection was conducted through focus group interview and it was proceeded by the time of data saturation. In this qualitative study, content analysis was conducted. Results: Five themes, 14 categories, and 33 subcategories, were emerged. The themes were 'Restrain themselves', 'Communion to the patients', 'Working environment provoking emotional tension', 'Respond to emotional events', 'Recovery of emotional energy'. Conclusion: Results indicated that surface acting of emotional labor such as, repression of personal desire and presenting the emotions that the organization ask nurse to express was related to psychosomatic symptoms, depression, burnout, poor job performance, increased mistakes, and low job satisfaction which eventually leads to nurses' turnover. In order to reduce negative influence of emotional labor, it is necessary to build positive organizational culture, to provide support from managers and co-workers. It is also important to improve work environment in order to do more deep acting since sharing emotions with patients can reduce the negative influence of emotional labor.

• 한국재난정보학회 논문집
• /
• 제3권2호
• /
• pp.79-93
• /
• 2007

With international urgence of terror situation, many methods of terror techniques and skills are appearing and more intense and threatening terror is braking out not only in the air(plane), but also in the sea(ship). Korea is surrounded by 3 sides of sea and is a proud maritime nation that should advance to foreign country through the sea because South Korea and North Korea are confronting. Korea depend on the maritime transportation, 99.7% of exporting, importing material resources. Therefore, acquisition of the marine safety has the great affect on national security and economical life. On the high tension of situation about threat and possibility of maritime terroism, the potential ways of the improvement policy for counter-tactics against big maritime terror are the following. First, we should construct clear and well-organized network for accurate information about maritime terrorism Second, we should have the information of all domestic, foreign passenger's ships Third, national important facilities such as atomic energy plant, thermo-electric power plant, shipyard need policies to manage all emergency situation Fourth, government authorities should improve tactic abilitities by competing with support and budget inside of nation as well as outside of nation. To develop big maritime terror of our country, we will have to hold cooperative training & tactics contest of big maritime terror by cooperating educational industry organization with similar institute, improve the ability of members of big terror and acquire tactics information by excavating and exchanging a new technique through tactics seminar and public hearing.

• Genomics & Informatics
• /
• 제15권4호
• /
• pp.142-146
• /
• 2017

More effective production of human insulin is important, because insulin is the main medication that is used to treat multiple types of diabetes and because many people are suffering from diabetes. The current system of insulin production is based on recombinant DNA technology, and the expression vector is composed of a preproinsulin sequence that is a fused form of an artificial leader peptide and the native proinsulin. It has been reported that the sequence of the leader peptide affects the production of insulin. To analyze how the leader peptide affects the maturation of insulin structurally, we adapted several in silico simulations using 13 artificial proinsulin sequences. Three-dimensional structures of models were predicted and compared. Although their sequences had few differences, the predicted structures were somewhat different. The structures were refined by molecular dynamics simulation, and the energy of each model was estimated. Then, protein-protein docking between the models and trypsin was carried out to compare how efficiently the protease could access the cleavage sites of the proinsulin models. The results showed some concordance with experimental results that have been reported; so, we expect our analysis will be used to predict the optimized sequence of artificial proinsulin for more effective production.