• Journal of Advanced Marine Engineering and Technology
• /
• 제40권2호
• /
• pp.131-137
• /
• 2016

In reliability analysis, it is quite common for the failure of any individual or item to be attributable to more than one cause. Moreover, observed data are often censored. Recently, progressive hybrid censoring schemes have become quite popular in life-testing problems and reliability analysis. However, a limitation of the progressive hybrid censoring scheme is that it cannot be applied when few failures occur before time T. Therefore, generalized progressive hybrid censoring schemes have been introduced. In this article, we derive the likelihood inference of the unknown parameters under the assumptions that the lifetime distributions of different causes are independent and exponentially distributed. We obtain the maximum likelihood estimators of the unknown parameters in exact forms. Asymptotic confidence intervals are also proposed. Bayes estimates and credible intervals of the unknown parameters are obtained under the assumption of gamma priors on the unknown parameters. Different methods are compared using Monte Carlo simulations. One real data set is analyzed for illustrative purposes.

• 한국인공지능학회지
• /
• 제3권1호
• /
• pp.4-6
• /
• 2015

These days, citizens have made change of food life to take Western style food and to suffer from diabetes because of excessive nutrition taking, less exercise, stress and other environmental factors. They may suffer from diabetes because of genetic defect, surgery of pancreas, disinfection and medicine and others. One of ten Koreans may have symptom of diabetes to be popular. The diabetes that is a kind of metabolic disease has high blood sugar at disorder of hyper insulinism and/or defect of insulin action. Long time high blood sugar may produce chronic disease of kidney, eyes, nerve, heart and blood vessel and others. The purpose of health care of diabetes patient was to reach target blood sugar by diet, physical exercise and medicine and to prevent and delay complication. Diabetes patient shall control blood sugar to keep healthy. The blood sugar control requires time and effort, and all of the patients are difficult to make effort and to spend time. You can control blood sugar by the application. The application allows patients to control blood sugar and to save time and efforts and to make small sized input and automation of remaining area. The service was limited to blood sugar graph, and user carries smart phone to conduct test and to have difficulty. Further study needs to solve the problems and to investigate blood sugar testing not carrying smart phone and to make application of easy control of blood sugar.

• 대한기계학회논문집A
• /
• 제21권2호
• /
• pp.305-316
• /
• 1997

A more efficient method for obtaining the fatigue life enhancement of a structure member with fastener holes is described. It is based on the combined process of cold-expansion and ring-indentation. Residual stresses were induced onto premachined holes using ring-indentation process near the fastener hole combined with cold-expansion. And residual stresses at the vicinity of a hole were evaluated using a fracture mechanics approach. The compressive residual stresses were larger using the combined process than is in the case of simple cold-expansion. Fatigue testing of aluminum specimens showed that the fatigue crack growth retardation emanating from a circular hole was greater for the combined process than for a simple cold-expansion alone.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권4호
• /
• pp.189-198
• /
• 2006

In order to improve the reliability of stator windings for hydro generators, it is necessary to detect the defective point and life assessment of the high voltage windings. Especially the on-line partial discharge (PD) test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting generators, this method has been proven the major testing technology in high voltage rotating machines nowadays. The purpose of this paper is to describe the method of the on-line PD measurement on stator windings for hydro-generator with 13 [kV] class ceramic coupler (CC), on-line PD measuring system, terminal box, and index parameters. Also, the developed PD measuring system and 13 [kV] class CC were installed Daechung-dam generator #2. It was found that this installed sensor and system had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz.

• 한국지역사회생활과학회지
• /
• 제17권1호
• /
• pp.87-99
• /
• 2006

The purpose of this study was to explore the relationship between self-rated health and Activity of Daily Living (ADL) and self-care behavior of rural elderly in Korea, focused on the difference among three distinctive living arrangements; living alone, living only with his/her spouse, and living with their married children. For this purpose, data were gathered from a nationwide survey, a total of 586 elderly aged 65 or older and living in rural area, using the structured questionnaire. Also, self-care behavior were categorized into 4 groups; life-style practice, medical self-care, adaption to functional limitation, and emotional management. The major findings are as follows; 1) Rural elderly perceived their health little and more 'bad' but their ADL capacity were 'not difficult', especially among elderly living with spouse. 2) The level of 20 items in self-care behavior ($1{\sim}5$score) was ranged from 2.51 to 3.81 score. The behavior level of regular exercise, setting up additional phone, taking a nutrient, and testing BP or pulse regularly were low but that of taking a medicine according to prescription, close contact with other people, and regular eating were proportionally high. 3) The majority of self-care behavior were correlated with subjective health positively but medical self-care behavior were correlated with subjective health or ADL negatively. Based on these results, policy implications are discussed.

• 재활간호학회지
• /
• 제18권2호
• /
• pp.75-87
• /
• 2015

Purpose: The purpose of this study was to develop a home-based self-management support intervention (SMSI) for enhancing pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD) in Korea. Methods: This methodological study was conducted by following these 4 steps: constructing the preliminary draft of a home-based SMSI from existing recommendation and a literature review on PR and self-management interventions; testing content validity with 6 experts in COPD; exploring clinical applicability of the intervention by applying it to 4 COPD patients; determining the final intervention. Results: The final intervention included 4 components and contents identified from the literature review as essentials for self-management of COPD patients: education; exercise training and practice including breathing, muscle strengthening and aerobic exercises; cognitive behavioral strategies including informative self-decision making, collaborative goal setting and supportive advice; and action planning for exacerbation. The intervention was designed to be run by a trained nurse and had 8 weekly sessions consisting of three 60-minute face-to-face sessions and five 20-minute phone-call sessions. Conclusion: The intervention developed in this study incorporates essential components of self-management, i.e. action plan and cognitive behavioral strategies, and will contribute to enhancing and maintaining effects of PR by increasing self-management in COPD patients.

• 품질경영학회지
• /
• 제43권3호
• /
• pp.221-238
• /
• 2015

Purpose: In this study, A reliability assurance model (or reliability program) is proposed to evaluate the reliability of an armed vehicle. The reliability assurance is performed through the reliability-centered activities during its life cycle of development/design, production, deployment, maintenance, and disposal. Methods: By reflecting the current situations of korea defense industry, a reliability assurance model is built up based on the benchmarking results of world leading companies' best practices in same fields. Results: The proposed reliability program of armed vehicles, which is based on the reliability program of ANSI/GEIA-STD 0009, uses DMAIC process of the six sigma methodology from design phase to testing and evaluation phase. Conclusion: This research is supposed to develop reliability program of armed vehicles by integrating DFSS, DFR and reliability growth process.

• 품질경영학회지
• /
• 제43권3호
• /
• pp.373-382
• /
• 2015

Purpose: In this paper, we developed a reliability index (RI) to efficiently compare reliability of products based on the design, development and production information such as reliability tests, quality, product life-cycle management. RI also can be applied to reliability prediction of a novel product as well as comparison evaluation among existing products. Methods: For evaluating RI, we proposed evaluation process which is composed of five steps. Target modules are selected based on warranty data and correlation analysis. Scores of selected target modules are calculated by scoring function. Finally, weights of RI model are determined by optimization method. Results: This paper presented an empirical analysis based on failure data of mobile devices. In this case study, we demonstrated that there is a direct correlation between evaluated RI and field failure probability of each product. Conclusion: We proposed the index for comprehensive and effective assessment of product reliability level. From the procedure of this study, we expected to be applied for reliability estimation of novel products and deduction of field failure-related factors.

• Communications for Statistical Applications and Methods
• /
• 제2권2호
• /
• pp.1-12
• /
• 1995

Let F be a life distribution with finite mean $\mu$ Then F is said to be in new better then worse than used in expectation (NBWUE(p)) class if $\varphi(u) {\geq} u$ for $0 {\leq}u{\leq}t_0$ and ${\varphi}(u) {\leq} u$ for $t_0< u {\leq} 1$ where ${\varphi}(u)$ is the scaled total-time-on-test transform and $p=F(t_0)$. We propose a testing procedure for $H_0$ : F is exponential against $H_1$ : NBWUE(p), and is not expontial, (or $H_1\;'$ : F is NWBUE (p), and is not exponential) using randomly censored data. Our procedure assumes kmowledge of the proportion p of the population that fail at or before the change-point $\t_0$. Know ledge of $\t_0$ itself is not assumed. The asymptotic normality of the test statistic is established and a Monte Carlo experiment is performed to investigate the speed of convergence of the test statistic to normality. The power of our test is also studied.

• 한국소음진동공학회논문집
• /
• 제25권7호
• /
• pp.481-486
• /
• 2015

This paper provides how to solve the problems analytically and experimentally that occur for testing the water injection pump under development. First of all, water injection pump, based on shaft system dynamic analysis, is verified by measuring the behavior of the shaft system. After the water injection pump is measured, the structural resonances which can cause excessive noise, degradation the equipment life and malfunction are found. Therefore, by changing the structural design, the reso- nance should be avoided. Application of the design variables to the experimentally resonance avoid- ance is difficult. So analytically, with application of the design variables, the design will be changed with mode analysis using FEM.