• 한국안전학회지
• /
• 제27권4호
• /
• pp.115-120
• /
• 2012

In order to establish preventive maintenance standards through analysis & reliability prediction of about 60,000pcs of 20kindsof relays and contractors used for Seoul subway trains, several life prediction methodologies were applied. Firstly, Occurrence, Severity, Detection were defined and predicted by applying operation characteristic of EMU to the number of actions of relays & contactors which the manufacturers generally offer as the life cycle data. Secondly, failure distribution and average life of parts were analyzed through interpretation of field data based on a lot of experience which had built up in the field for a long time. Finally, using the 217PLUS standard as a reliability prediction program, comparative analysis of use reliability and inherent reliability was done through reliability prediction at the part level and system level.

• 예술인문사회 융합 멀티미디어 논문지
• /
• 제8권7호
• /
• pp.475-484
• /
• 2018

전기철도차량의 추진제어장치는 자동차의 엔진에 해당되는 핵심 주요부품이며 이를 제어하는 장치는 GDU(Gate Drive Unit)라는 장치를 이용한다. 또한, 추진제어장치의 고장 빈도를 파악해보면 GDU에 대한 부적합 비율이 가장 높았다. GDU는 외국산 도입으로 인하여 핵심기술의 접근이 불가하였고, 제작사의 GDU 단종으로 전반적인 유지보수 활동에 전반적인 문제점이 있었다. GDU는 최장 23년부터 최근 14년의 장기간 사용으로 수명이 도래하였다. 본 연구는 이러한 문제점을 해결하고자 호환이 가능한 GDU의 확보와 고장을 분석하여 적정수명을 파악하기 위한 것으로, 기존의 상태검사 위주의 유지보수 방법 개선을 위해 설계를 변경하여 추진제어장치의 GDU를 커패시터 교환 형으로 개발하였다. 전체수명에 비해 비교적 수명이 짧은 구성부품의 유지보수는 필수이며, 대부분의 건설초기의 최초 외산도입 부품은 기술종속 및 장기운영의 결과로 관련 부품의 단종이 발생하면 고장발생 시 수급불가 등으로 기본적인 교환에 대한 유지보수에 문제점이 발생되고 있으나, 25년 이상으로 전체수명이 긴 철도차량의 특성상 앞으로도 상당기간 운영이 필요하여 개조 혹은 대체품 개발로 부품확보 및 일정수준의 품질을 유지할 필요가 강조되며, 이에 대한 연구는 보다 구체적이고 실증적으로 이루어져야 한다. 커패시터 교환 형 GDU는 커패시터 모듈의 분리를 통해 정전용량을 쉽게 측정하여 수명을 판단하고, 단품 시험과 커패시터의 수명을 측정하여 정확한 예방유지보수를 할 수 있어서 운행 중 열차의 부적합을 미리 예방할 수 있으며, 24개월 이상의 영업 운전을 통하여 한건의 부적합 없이 영업운행에 성공하여 기존품의 대체 가능여부를 검증하였다.

• 미생물학회지
• /
• 제43권4호
• /
• pp.264-272
• /
• 2007

인간면역결핍바이러스(Human Immunodeficiency Virus; HIV) 진단을 위한 초고속 실시간 PCR법을 개발하였다. 검출 대상의 DNA 염기서열은 495염기 HIV-1 특이 env 유전자(gi_l184090)및 294염기 HIV-2 특이 env 유전자(gi_1332355)를 사용하였다. 초고속 실시간 PCR은 microchip에 $6\;{\mu}l$의 PCR 용액을 탑재하는 $Genspector^{TM}$ (Samsung, Korea)을 사용하였으며, PCR의 각 회전 중 단지 두 단계(denaturation, annealing/extension)를 극단적으로 짧은 시간을 주어 수행하게 하였다. 융점분석을 포함한 30회전의 PCR 검색 시간은 총7분30초 이내에 완료되었으며, HIV-1 특이 117염기와 HIV-2 특이 119염기의 PCR산물은 최소 $2.3{\times}10^3$개의 각 env 유전자로부터 30회전의 2단계 초고속 PCR에 의해 성공적으로 증폭시킬 수 있었다. 이러한 초고속 실시간 PCR법은 HIV의 빠른검색뿐 아니라, 다른 병원채의 빠른 검색에도 유용하계 적용될 수 있을 것이다.

• 종양간호연구
• /
• 제1권1호
• /
• pp.32-43
• /
• 2001

High risk breast cancer patients receive aggressive treatments such as APBSCT in order to prevent the recurrence. These treatments take a long time and decrease the quality of life of patients as a result. The purpose of this study is to examine when the changes of quality of life are dramatic in general and in specific dimension. This is a time series study of two types of treatment groups, in which 15 patients were treated by chemotherapy only and nine patients by auto-peripheral blood stem cell transplantation. Subjects were in this study were stage III and above of breast cancer. Data were collected from April 1999 to April 2000 with the 3 month-interval starting after 3rd cycle of chemotherapy. Data were collected 3 times ; treatment period, treatment finishing period and 3 months later after the treatment. Ferrell's QOL instrument was used which had been developed for the breast cancer patients in 1989. Repeated Measure ANOVA was used to examine differences of quality of life at 3 points of time respectively. As a result, average age was 43.29 years (4.38yrs) and the number of married person was 22(91.7%). Scores of quality of life were 5.45 at 1st period after 3rd cycle of chemotherapy, 5.17 after treatment, 5.10 at 3 months later after treatment and difference of quality of life was decreased according to period of treatment (P=.085). Only the psychological dimension of the quality of life showed the significant difference (P=.045). Two different treatment groups showed a difference of quality of life at 3 month later after treatment. In conclusions, high risk breast cancer patients showed the decreased quality of life related to treatment up to 3 months later of treatment. Subjects who received APBSCT returned to the normal quality of life more rapidly than those who received chemotherapy. Psychological nursing intervention was needed during the whole period of treatment.

• 가정과삶의질연구
• /
• 제23권1호
• /
• pp.187-195
• /
• 2005

The purpose of this study is to examine the influence of parent-to-child financial transfers and economic resources on financial transfers, caregiving, and time donated from middle-aged adult children to their elderly parents. Analyzing data from the Wisconsin Longitudinal Study, which provides long-term observations of financial reciprocity and recent reports about elder care, the current study finds strong positive effects of prior parent-to-child financial transfers in the models of caregiving and time; which indicates the importance of reciprocity. In terms of determinants of resource transfers, the findings of logistic regression analyses suggest that the economic resources of parents and adult children are strong determinants of child-to-parent financial resource transfers. Sociodemographic characteristics of parents and respondents were observed as strong determinants of caregiving or time. In addition, caregiving responds more to the health and income levels of parents whereas donated time is responsive to the net worth of parents and parents' status. For adult children, gender is a strong determinant of both caregiving and time donation. The long-term health problem of adult children is a statistically significant predictor of caregiving, while the employment status of adult children and the number of siblings have statistically a significant association with time donated to care for the parents.

• Smart Structures and Systems
• /
• 제21권2호
• /
• pp.171-185
• /
• 2018

Maintenance of deteriorated bridge structures has always been one of the challenging issues in developing countries as it is directly related to daily life of people including trade and economy. An effective maintenance strategy is highly dependent on timely inspections on the bridge health condition. This study is intended to investigate an approach for detecting bridge damage for the long-term health monitoring by use of copula theory. Long-term measured data for the seven-span plate-Gerber bridge is investigated. Autoregressive time series models constructed for the observed accelerations taken from the bridge are utilized for the computation of damage indicator for the bridge. The copula model is used to analyze the statistical changes associated with the modal parameters. The changes in the modal parameters with the time are identified by the copula statistical properties. Applicability of the proposed method is also discussed based on a comparison study among other approaches.

• Journal of Yeungnam Medical Science
• /
• 제40권1호
• /
• pp.12-22
• /
• 2023

Graves disease (GD) is the most common cause of hyperthyroidism, accounting for more than 90% of cases in Korea. Patients with GD are treated with any of the following: antithyroid drugs (ATDs), radioactive iodine (RAI) therapy, or thyroidectomy. Most patients begin treatment with ATDs, and clinical guidelines suggest that the appropriate treatment period is 12 to 18 months. While RAI treatment and surgery manage thyrotoxicosis by destroying or removing thyroid tissue, ATDs control thyrotoxicosis by inhibiting thyroid hormone synthesis and preserving the thyroid gland. Although ATDs efficiently control thyrotoxicosis symptoms, they do not correct the main etiology of GD; therefore, frequent relapses can follow. Recently, a large amount of data has been collected on long-term ATDs for GD, and low-dose methimazole (MMZ) is expected to be a good option for remission. For the long-term management of recurrent GD, it is important to induce remission by evaluating the patient's drug response, stopping ATDs at an appropriate time, and actively switching to surgery or RAI therapy, if indicated. Continuing drug treatment for an extended time is now encouraged in patients with a high possibility of remission with low-dose MMZ. It is also important to pay attention to the quality of life of the patients. This review aimed to summarize the appropriate treatment methods and timing of treatment transition in patients who relapsed several times while receiving treatment for GD.

• Journal of Mechanical Science and Technology
• /
• 제17권4호
• /
• pp.469-476
• /
• 2003

Despite of considerable research results or uniaxial tension creep available for superalloys, few studies have been made on high temperature creep using the Initial Stram Method (ISM) In this paper, the real-time prediction of high temperature creep strength and creep lift for the nickel-based superalloy Udimet 720 (high-temperature and high-pressure gas turbine engine materials) was performed on round-bar type specimens under pure static load at the temperatures of 538$^{\circ}C$. 649$^{\circ}C$, and 704$^{\circ}C$. The predictive equation derived from the ISM in creep tests showed better reliability than those from LMP (Larson-Miller Parameter) and LMP-lSM (Larson Miller Parameter-Initial Strain Method) specially for long time creep prediction (10$^3$∼10$\^$5/h).

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 추계학술대회 논문집
• /
• pp.437-440
• /
• 2000

In this study, the interfacial dielectric breakdown phenomenon of interface between Epoxy and Rubber was discussed, which affects the stability of insulation system of power delivery devices. The breakdown strength of specimens are observed by applying high AC voltage at the room temperature. The breakdown times under the constant voltage below the breakdown voltage were gained. As constant voltage is applied, the breakdown time is proportion to the breakdown strength. The life exponent n is gained by inverse power law and the long time breakdown life time can be evaluated.

• 한국생활과학회지
• /
• 제13권1호
• /
• pp.111-122
• /
• 2004

The purpose of the study lied on supporting the reeducation program which was focused on the demand with the clients by analyzing the recognition on the real situations of the reeducation on the hair designers in the nation. As a result on the subject, the responders said they could usually learn new information through the various seminars that were held by beauty product suppliers and companies, and most of the high school or under high school level designers have participated in various seminars while the designers who graduated from a junior college or universities had experienced new trends at life time education establishments(p<0.01). A hair designer who was single and paid low salary usually depended on the course inside the shop(p<0.01), and most of the information they got was through the suppliers of the beauty products. In that case, regular sources of information, such as educational establishments, informative magazines, Internet were highly recommended. A reason for unsatisfactory reeducation was due to lack of time and a reason for not participating the seminar was also due to time shortage caused by regular working hours, which was reflecting the real situation of the hair designers. As a suggestion for the reeducation establishment, most of the responders wanted vocational schools or life-time educational center. They wanted a fixed regular period for reeducation, especially over the weekend for after working hours. It means they want long-time systematic education. Considering the results, a course which is organized for a long-time systematic purpose is suggested for the hair dressers who want to be professionals in the field with the class equipped with contents of the classes, period, and place. For the purpose to be realized, improvement of the working hours in needed and it will be an incentive to make the hair designers satisfied with their work.