• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.226-238
• /
• 2011

RAMS (Reliability, Availability, Maintainability, Safety) study has received far less rigorous analysis in the system performance and integration level, and RCM (Reliability Centered Maintenance) research has been studying to improve the maintenance efficiency in the operational steps based on collected data of real operational cases. This paper analyzes the basic concepts based on KS X ISO/IEC 15288 system life-cycle process in the whole system for the light rail transit construction, and the research suggests an approach to the management process of the applicable main tasks. The paper "Management Process Study to RAMS Application of Light Rail Transit System" introduces Airport Rail cases and guidelines by using RAMS which is the major role in the system engineering technical process of ISO/IEC 15288 (International Organization for Standardization/International Electrotechnical Commission 15288) to apply RAMS in domestic light rail transit efficiently, the aim of this study is to broaden of understanding RAMS.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.789-795
• /
• 2008

In recent, the rolling stocks are gradually complicated in respect with design and production to improve the safety and reliability. Also, the reliability centered maintenance corresponding with system specification or technical requirements is needed to meet the higher quality in railway service. In present, each railway authorities are collecting the failure's data using information system, applying those for maintenance works. However, this system has not established with systematic and scientific approach. This paper represents the existing activities and plans for RCM management system for AREX's EMU.

• 감성과학
• /
• 제12권4호
• /
• pp.489-500
• /
• 2009

본 연구는 정보검색의 핵심 개념인 적합성을 사용자 중심 관점에서 접근한 연구이다. 적합성에 관한 기존 연구들은 적합성 판단에 영향을 주는 다양한 기준들을 정의해 왔다. 본 연구는 적합성 유형별로 사용자가 적합성을 판단하는 기준과 적합성 유형 간의 관계를 정보 검색 과제별로 연구함으로써 사용자 중심 적합성 판단 모형을 알아보았다. 본 연구는 7개의 사용자 적합성 판단 기준-주제성, 신선성, 신뢰성, 이해가능성, 특수 성, 구체성, 흥미성-과 3가지의 사용자 적합성 유형-인지 적합성, 상황 적합성, 정서 적합성-을 고려하였다. 이를 대학생 사용자들을 대상으로 검색 과제 수행 후 설문에 답하는 반 제어(semi-controlled) 설문 방법을 이용하여 자료를 수집하였고, 구조방정식 모형으로 분석하였다. 연구 결과 주제성, 신뢰성은 모든 검색 과제에 중요한 적합성 판단 기준이었고, 과제 유형별로 볼 때 사실 검색 과제에서는 주제성, 신뢰성, 신선성, 구체성, 흥미성이, 문제 해결 검색 과제에서는 주제성, 신뢰성, 이해가능성, 특수성이, 의사 결정 검색 과제에서는 주제성, 신뢰성, 신선성, 이해가능성, 구체성, 특수성, 흥미성이 적합성을 판단하는 주요 기준들이라는 것을 확인할 수 있었다. 또한 적합성 유형들 간의 관계도 실증적으로 밝힐 수 있었다. 본 연구는 적합성 판단 기준과 적합성 유형 간의 관계를 정보 검색 과제별로 확인함으로써 보다 구체적인 사용자 중심의 적합성 판단 모형을 확립하였다는 점에서 의의를 가진다.

• 간호행정학회지
• /
• 제14권3호
• /
• pp.219-228
• /
• 2008

Purpose: The purpose of this study was to develop a measurement scale of nursing competence for nurses working in general wards, and to test the validity and reliability of the scale. Method: A methodological study design was used, consisting of 3 steps as conceptual framework decision, measurement items development, and testing of validity and reliability. In order to verify content validity, 16 experts reviewed the concept of each competences and measurement items. The developed measurement items were tested from 301 nurses in one hospital. Factor analysis and item analysis were applied to establish the scale's construct validity and reliability. Result: The final scale consists of nine dimensions with 70 items. The overall scale reliability had a Cronbach's alpha of 0.98, and the demensions Cronbach's alpha ranged from 0.88 to 0.95. The factor loading of construct validity was from 0.40 to 0.83. The explained variance from the 9 extracted factors was 70.93% of the total variance, and final factors were labeled as critical thinking, resources management and professional development, ability of ward management, application of nursing process, ethical accountability, respectful consideration, patient centered approach, crisis management, and leadership. Conclusion: This measurement scale can be utilized to evaluate nursing competence for nurses working in general wards.

• Geomechanics and Engineering
• /
• 제21권6호
• /
• pp.513-525
• /
• 2020

Slopes stabilised with piles are seldom analysed considering uncertainties in the parameters of the pile-slope system. Reliability analysis of the pile-slope system quantifies the degree of uncertainties and evaluates the safety of the system. In the present study, the reliability analysis of a slope stabilised with piles is performed using the first-order reliability method (FORM) based on Hasofer-Lind approach. The implicit performance function associated with the factor of safety (FS) of the slope is approximated using the response surface method. The analyses are carried out considering the design matrices formulated based on both the 2^k factorial design augmented with a centre run (2^k fact-centred design) and face-centered cube design (FCD). The finite element method is used as the deterministic model to compute the FS of the pile-slope system. Results are compared with the results of the Monte Carlo simulation. It is observed that the optimum location of the row of piles is at the middle of the slope to achieve the maximum FS. The results show that the reliability of the system is not uniform for different pile configurations, even if the system deterministically satisfies the target factor of safety (FS_t) criterion. The FS_t should be selected judiciously as it is observed that the reliability of the system changes drastically with the FS_t level. The results of the 2^k fact-centred design and FCD are in good agreement with each other. The procedure of the FCD is computationally costly and hence the use of 2^k fact-centred design is recommended, provided the response of the system is sufficiently linear over the factorial space.

• 천문학회보
• /
• 제44권1호
• /
• pp.79.2-79.2
• /
• 2019

Based on three types of 2-point statistics (galaxy clustering, galaxy-galaxy lensing, and cosmic shear power spectra) from the Deep Lens Survey (DLS), we constrain cosmology and baryonic feedback. The DLS is a deep survey, so-called a precursor to LSST, reaching down to ~27th magnitude in BVRz' over 20 deg2. To measure the three power spectra, we choose two lens galaxy populations centered at z ~0.27 and 0.54 and two source galaxy populations centered at z ~0.64 and 1.1, with more than 1 million galaxies. We perform a number of consistency tests to confirm the reliability of the measurements. We calibrated photo-z estimation of the lens galaxies and validated the result with galaxy cross-correlation measurement. The B-mode signals, indicative of potential systematics, are found to be consistent with zero. The two cosmological results independently obtained from the cosmic shear and the galaxy clustering + galaxy-galaxy lensing measurements agree well with each other. Also, we verify that cosmological results between bright and faint sources are consistent. While there exist some weak lensing surveys showing a tension with Planck, the DLS constraint on S8 agrees nicely with the Planck result. Using the HMcode approach derived from the OWLS simulation, we constrain the strength of baryonic feedback. The DLS results hint at the possibility that the actual AGN feedback may be stronger than the one implemented in the current state-of-the-art simulations.

• 유통과학연구
• /
• 제12권6호
• /
• pp.31-39
• /
• 2014

Purpose - Environmental issues, climatic changes, and greenhouse gases are problems to be solved at a global level. With an increased emphasis on the environmental and social responsibility of the management of companies, the manner in which companies approach quality-oriented culture and their individual sustainability management are being discussed as truly important issues to help them secure their competitiveness and growth strategies. This study proposes strategic directions to help manufacturers not only in expanding their competitive quality-oriented company culture but also in strengthening their sustainability management abilities. This study conducts a literature review and empirical research to examine how significantly the variables of a quality-oriented company culture, customer-centered management, and process-centered and supply chain management-centered cooperation affect sustainability management performance in relation to economic profitability, environmental integrity, and social responsibility. Research design, data, and methodology - To verify research models and hypotheses, the study examined 170 companies using a questionnaire survey conducted over six weeks, and involved the performance of data analysis on 146 samples. Questionnaire responses were calibrated based on a Likert scale. The study used the Smart PLS 2.0 program designed for PLS (partial least squares), an analysis instrument of SEM (structural equation modeling). The study then verified empirical research hypotheses working on reliability analysis, validity analysis, factorial analysis, and path analysis. Results - Among the nine hypotheses, four are accepted and the rest are rejected. A quality-oriented company culture focusing on customer-centered management significantly influenced the maintainability management performance of environmental integrity and social responsibility, while economic profitability was dismissed. A process-focused quality-oriented company culture was significantly concerned with economic profitability but not with environmental integrity or social responsibility. A supply-chain cooperative company culture had a significant effect on economic profitability but not on environmental integrity or social responsibility. Conclusion - This study proposes strategic directions to help manufacturers expand their competitive quality-oriented company culture as well as strengthen abilities with sustainability management. It conducts a literature review and empirical research to examine how significantly the variables of quality-oriented company culture, customer-centered management, and process-centered and supply chain management-centered cooperation affect sustainability management performance in relation to economic profitability, environmental integrity, and social responsibility. There are two main conclusions. First, companies should consider the need for social responsibility management and environmental transparent management-focused maintainability management as avenues to create new markets and business, thereby helping the companies secure a reputation for having a customer and process-centered quality-oriented company culture by creating shared values between supply chains and enabling win-win situations through cooperation. Second, we are marching towards a creative win-win era from a society of conflicts and ruptures. Companies should understand that social responsibility management and supply chain management (SCM)-focused cooperation are the foundations of sustainable development, as they try to improve their culture while pursuing both win-win relationships with interested parties and equity in various conflictive relations.

• 한국자동차공학회논문집
• /
• 제13권5호
• /
• pp.7-18
• /
• 2005

Over the past twenty years, the maintenance system has been developed and its importance has been increased. For the effective maintenance of the urban transit, we have developed the maintenance system based on the concept of RCM(Reliability Centered Maintenance). RCM analysis is a systematic approach to developing a cost-effective maintenance strategy based on the various components's reliability of the system in question. It is performed according to process that includes the following steps; definition of function and functional failures of the systems, construction of RB D(Reliability Block Diagram), performance of FMEA(Failure Modes & Effects Analysis) and calculation of the reliability index. The final process of RCM is to determine appropriate failure maintenance strategies. This paper aims to define the procedure of maintenace based on the concept of RCM for urban transit. The key for a successful maintenance system is an automated scheduling to the maximum extent possible and timely executions. The developed system issues maintenance plan and repair request based on analyzed data and maintenance experience.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제15권1호
• /
• pp.27-32
• /
• 2015

Functional safety is part of the overall safety relating to the equipment under control (EUC) and the EUC control system that depends on the correct functioning of the electrical/electronic/programmable electronic (E/E/PE) safety-related systems. Since the complexity of the medical equipment is increased, manufactures have to obtain functional safety as well as basic safety. This study proposes a perspective for applying functional safety to medical equipment. The research is carried out with respect to overall safety life-cycle of functional safety and essential performance of the medical equipment. The relationship between functional safety and essential performance is identified centered on the safety function. The essential performance using E/E/PE systems is defined as a safety function of functional safety. This approach is applied to a ultrasound imaging system as a case study.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.784-791
• /
• 2007

Most operational organization and railway authority which conduct scheduled maintenance(SM) have carried out the preventive maintenance(PM) based on the information provided from supplier and manufacturer of railway system. However these activities are far away from reality and low the efficiency, it is because an appropriate methods for system selection didn't take into account for improving maintenance efficiency. Therefore, the current SM tasks and maintenance activities lead to lots of spend on the cost and time. To solve the above problem, this thesis presents new approach methodology. This proposes the criteria for reliability centered maintenance(RCM) system selection through level of quantification of each parameter, i.e, frequency, severity and maintenance cost, etc. To do this, the field operation data and information of maintenance cost are essential. As applying this methodology, we can look forward to improving efficiency of PM/SM, and reducing cost.