Reliability analysis of the components frequently starts with the data that manufacturer provides. If enough failure data are collected from the field operations, the reliability should be recomputed and updated on the basis of the field failure data. However, when the failure time record for a component contains only a few observations, all statistical methodologies are limited. In this case, where the failure records for multiple number of identical components are available, a valid alternative is combining all the data from each component into one data set with enough sample size and utilizing the useful information in the censored data. The ROK Navy has been operating multiple Patrol Killer Guided missiles (PKGs) for several years. The Korea Multi-Function Control Console (KMFCC) is one of key components in PKG combat system. The maintenance record for the KMFCC contains less than ten failure observations and a censored datum. This paper proposes a Bayesian approach with a Dirichlet mixture model to estimate failure time density for KMFCC. Trends test for each component record indicated that null hypothesis, that failure occurrence is renewal process, is not rejected. Since the KMFCCs have been functioning under different operating environment, the failure time distribution may be a composition of a number of unknown distributions, i.e. a mixture distribution, rather than a single distribution. The Dirichlet mixture model was coded as probabilistic programming in Python using PyMC3. Then Markov Chain Monte Carlo (MCMC) sampling technique employed in PyMC3 probabilistically estimated the parameters’ posterior distribution through the Dirichlet mixture model. The simulation results revealed that the mixture models provide superior fits to the combined data set over single models.

All machines deteriorate in performance over time. The phenomenon that causes such performance degradation is called deterioration. Due to the deterioration, the process mean of the machine shifts, process variance increases due to the expansion of separate interval, and the failure rate of the machine increases. The maintenance model is a matter of determining the timing of preventive maintenance that minimizes the total cost per wear between the relation to the increasing production cost and the decreasing maintenance cost. The essential requirement of this model is that the preventive maintenance cost is less than the failure maintenance cost. In the process mean shift model, determining the resetting timing due to increasing production costs is the same as the maintenance model. In determining the timing of machine adjustments, there are two differences between the models. First, the process mean shift model excludes failure from the model. This model is limited to the period during the operation of the machine. Second, in the maintenance model, the production cost is set as a general function of the operating time. But in the process mean shift model, the production cost is set as a probability functions associated with the product. In the production system, the maintenance cost of the equipment and the production cost due to the non-confirming items and the quality loss cost are always occurring simultaneously. So it is reasonable that the failure and process mean shift should be dealt with at the same time in determining the maintenance time. This study proposes a model that integrates both of them. In order to reflect the actual production system more accurately, this integrated model includes the items of process variance function and the loss function according to wear level.

A warehouse is more than just a place to store goods but also creates a time utility gap between production and consumption that is important in the development of trade and commerce. Malaysia has a high aspiration to be the most popular gateway in Asia. However, Malaysia Productivity Corporation has claimed that particularly in efficiency and productivity aspects, the warehouse industry is less incline to innovate and make improvement to increase. There are ten failure factors that had been identified during literature survey affecting to the warehouse operations efficiency. Therefore, this study intends to analyse and select the main failure factors that mostly affecting the warehouse operations efficiency. A Fuzzy Analytic Hierarchy Process (FAHP) technique has been used in this study to calculate the weight value of each variable through a pair-wise comparison method. The finding highlighted the four main failure factors which are ‘equipment’, ‘environment concern’, ‘special handling consideration’ and ‘human factor’ that influence directly to the warehouse operations efficiency. This paper has contributed to a new knowledge of complex warehouse operation area with recommendations action that shall be taken to manage the possible risk in future, which will also contribute to achieve the government goals.

Recently, automobile manufacturing companies, which are major customers of them, are requiring IATF 16949 (ISO/TS 16949) certification as a mandatory requirement to secure product quality. In particular, IATF 16949 : 2016, revised in October 2016, was reinforced product traceability requirements for production information management by lot in the production process. Therefore, small and medium-sized precision parts processing companies in the automobile industry are very difficult to survive due to quality and price competition for customers satisfaction. MES (Manufacturing Execution System) is required to solve this problem. However, small and medium sized precision parts processing enterprises are reluctant to introduce the MES which is not suitable for the manufacturing environment of them such as high cost and low utilization. Even if the system is introduced, it is difficult to operate and maintain the system because the lack of computer manpower. In this paper, we propose a method for building a lot tracking system for small and medium precision parts processing companies by reviewing relevant literature and analyzing cases. In addition, by managing the production history for each lot of the final product in the system, we will grasp the effect of reducing the quality failure cost obtained by minimizing the range of defect selection.

Since guided missiles with the characteristics of the one-shot system remain stored throughout their entire life cycle, it is important to maintain their storage reliability until the launch. As part of maintaining storage reliability, period of preventive test is set up to perform preventive periodic test, in this case failure detection rate has a great effect on setting up period of preventive test to maintain storage reliability. The proposed method utilizes failure rate predicted by the software on the basis of MIL-HDBK-217F and failure mode analyzed through FMEA (Failure Mode and Effect Analysis) using data generated from the actual field. The failure detection rate of using the proposed method is applied to set periodic test of the actual guided missile. The proposed method in this paper has advantages in accuracy and objectivity because it utilizes a large amount of data generated in the actual field.

In this study, temperature and pressure of guided wave radar products are transmitted at high temperature and high pressure. In the case of transmission of temperature pressure, high temperature and high pressure steam leak from the guide rod part to the atmosphere causes the failure. Therefore, in this study, structural analysis and thermal flow analysis of the product are performed to identify the problem of the product, so as to prevent leakage in the product development by grasping the cause of the leakage of the product. In this study, if the method of assembling the lower end of the piston rod and the gasket is changed from line contact to face contact,

The seismic safety of nuclear power plants has always been emphasized by the effects of accidents. In general, the seismic safety evaluation of nuclear power plants carries out a seismic probabilistic safety assessment. The current probabilistic safety assessment assumes that damage to the structure, system, and components (SSCs) occurs independently to each other or perfect dependently to each other. In case of earthquake events, the failure event occurs with the correlation due to the correlation between the seismic response of the SSCs and the seismic performance of the SSCs. In this study, the EEMS (External Event Mensuration System) code is developed which can perform the seismic probabilistic safety assessment considering correlation. The developed code is verified by comparing with the multiplier n, which is for calculating the joint probability of failure, which is proposed by Mankamo. It is analyzed the changes in seismic fragility curves and seismic risks with correlation. As a result, it was confirmed that the seismic fragility curves and seismic risk change according to the failure correlation coefficient. This means that it is important to select an appropriate failure correlation coefficient in order to perform a seismic probabilistic safety assessment. And also, it was confirmed that carrying out the seismic probabilistic safety assessment in consideration of the seismic correlation provides more realistic results, rather than providing conservative or non-conservative results comparing with that damage to the SSCs occurs independently.

In this paper, the experimental study and finite elements analysis were conducted on homogeneous and dissimilar metals single lap-shear bonded joints to investigate the factor that affect the joint failure load. It was found that factors which have the significant effects on the failure load of the joint was stiffness of the adherends. And from experimental results, it can be confirmed that the failure load increases linearly with overlap length increases. And the failure load of dissimilar metal joints is approximately 1KN(10 ～17%) larger than homogeneous metal joints. In order to confirm this phenomenon, the stress distribution and strain distribution of the specimens were analyzed through the finite element analysis. The difference between homogeneous metals joints and dissimilar metals joints is that stress and strain in adhesive are concentrated at the end of the overlap zone close to aluminium which has lower rigidity than aluminium in case of dissimilar metals joints. From high rigidity of steel, the stress concentration in bonds are decreased and it cause increase of the failure strength at dissimilar metal joints.

Echocardiography is one of the most useful diagnostic techniques for differentiating heart disease as well as mitral valve lesion. Forty client-owned small breed dogs (weight, 2.3−13.2 kg) aged between 8−17 years with myxomatous mitral valve degeneration (MMVD) were included in the present study. The diagnosis of MMVD in dogs was made based on the clinical signs, chest radiography data, and echocardiographic findings. Echocardiographic examinations were conducted in accordance with recommended standards for dogs. M-mode, Doppler, and 2D echocardiography were performed in left and right lateral recumbency. 2D echocardiography was used to measure LA and Ao diameter from 2D short axis at the level of the aortic valve. In the comparison of conventional echocardiography indices in dogs with different stages of heart failure with MMVD, significant differences were observed in E/A ratio (p=0.005), EDV (p<0.001), EDVI (p<0.001), E-peak velocity (p= 0.001), ESV (p=0.028), ESVI (p=0.004), LA (p<0.001), LA/Ao Ratio (p<0.001), LVIDd (p<0.001), LVIDd/Ao Ratio (p<0.001), LVIDs (p=0.036), LVIDs/Ao Ratio (p=0.002), and MR Velocity (p=0.026). In addition, distinct correlations were found in EDV (r=0.712), LA/Ao ration (r=0.830), LVIDd (r=0.724), and LVIDd/Ao ratio (r=0.759). This study found that known conventional echocardiographic indices, including EDV, LA/Ao ratio, LVIDd dimension, and LVIDd/Ao ratio correlated with the severity of MMVD in point of significant differences and distinct correlations.

본 연구의 목적은 국내 레스토랑 이용객의 서비스 실패 후 감정변화에 영향을 미치는 실패 귀인 요소, 그리고 고객의 브랜드 관계 품질이 서비스 실패 귀인 지각에 대한 환원효과를 검증하는 것이다. 본 연구의 시사점으로는 귀인이론은 귀인이론과 귀인적 이론으로 구분할 수 있는데 한 모형에서 귀인이론에 영향을 미치는 개인 신념과 귀인 후의 감정반응 간의 영향관계를 통합적으로 측정하는 연구는 미미하다. 신념(BRQ: Brand Relationship Quality)-귀인-감정 3단계 모형을 구축하고 충돌 감정 반응(분노 VS동정)의 독립성을 같이 검증되었다. 먼저, 감성적BRQ(친밀감 및 사랑)은 통제가능성 귀인에 미치는 환원효과가 있는데 행동적BRQ(상호의존)은 통제가능성 귀인에 미치는 확대효과가 있는 것으로 나타났다. 관리적 관점에서 레스토랑 관리자는 고객의 서비스 실패의 반복 발생 가능성 지각을 낮추고 고객의 동정을 환기해야 한다. 통합적으로 레스토랑 관리자는 고객의 서비스 실패 귀인 지각을 잘 조절하고 고객의 BRQ이 감정반응에게의 영향효과를 환원시켜야 한다. 여러 가지의 서비스 회복 방안을 수립하고 귀 인을 잘 조절해야 한다. 뿐만 아니라, BRQ은 각각 분노 및 동정에 다른 효과(확대VS환충)가 있기 때문 에 고객 BRQ의 특성에 따라 다른 서비스 실패 회복 방안을 제시해야 한다. 예를 들면, 이성적 BRQ 고객에게 금전 보상이나 공정성 거래, 친밀감 및 사랑 고객에게 감정배려, 상호의존 고객에게 호혜성 설득 등 방안을 상황에 맞게 개발해야 한다. 본 연구는 서비스 실패 후 귀인의 매개효과를 탐색적으로 검증하 였는데 BRQ-귀인-감정 과정에서의 여러 가지 조절요인을 고려하지 않는 한계점이 있다. 따라서 추후의 연구에서 서비스 실패 강도의 조절효과를 고려해야 하고 더 완전한 모형을 구축해야 한다.

본 실험은 마우스를 이용해 급성신부전에 대한 WK 추출물의 효과를 알아보고자 하였다. 실험 종료 후, 대조군은 항암제 주입 후 정상 대조군에 비해 혈중 BUN 및 creatinine 수치가 상승된 것을 확인할 수 있었고, WK-50군, WK-100군 및 WK-200군은 대조군에 비해 수치가 감소된 것을 확인할 수 있었다. 그 중 WK-200군은 정상 대조군과 유의한 수준의 혈중 BUN 및 creatinine 수치가 관찰되었다. 조직학적 결과에서 적출한 신장 장기의 형태학적 손상을 알아본 결과, 대조군에서는 현저한 신손상이 관찰되었다. 반면, WK-50군 및 WK-100군에서는 신손상이 관찰되었으나 대조군에 비하여 그 정도가 심하지 않았고, 특히 WK-200군에서는 신손상이 거의 관찰되지 않았음을 알 수 있었다. 따라서 WK 추출물은 급성신부전에 유의한 효과를 보이는 것으로 생각된다.

본 연구는 창업실패관련 지각된 혜택이 창업의도에 미치는 영향에 대해 연구하고, 두 변수와의 관계에 서 창업자기효능감이 매개변수로서의 영향을 미치는지와 창업경험유무가 조절변수로서의 영향을 미치는 지를 확인하고자 했다. 본 연구의 표본은 서울 소재 대학 창업보육센터 졸업기업 대표자 및 청년창업센터 창업가, 대학교 창업 강좌 수강생으로, 552명을 표본으로 수집하였다. 수집된 표본을 대상으로 타당성 및 신뢰성을 검증하였고, 단순회귀분석, 매개효과 및 조절효과 분석을 통해 가설을 검증하였다. 분석한 결과, 창업실패관련 지각된 혜택은 창업의도와 창업자기효능감에 유의한 영향을 미침을 알 수 있었다. 그리고 창업자기효능감은 창업의도에 유의한 영향을 미치며, 창업실패관련 지각된 혜택과 창업의도 사이를 매개함을 알 수 있었다. 또한 창업경험유무는 창업실패관련 지각된 혜택과 창업자기효능감 사이에서 조절변수로서 영향을 미치는 것을 알 수 있었다. 연구의 결과에서 창업실패관련 지각된 혜택, 즉 창업지원정책이 창업실패 예방에 유용하다는 인지가 창업의도와 창업자기효능감을 제고하므로 창업지원 사업의 유용성에 대한 인지제고가 필요함을 알 수 있었다. 그리고 창업자기효능감은 직접 창업의도를 제고하고, 창업실패관련 지각된 혜택과 창업의도를 매 개하므로, 창업자기효능감을 제고하기 위해 정부 및 지방자치단체가 창업지원 사업계획을 수립할 때, PBL, Cash-class 등 창업자기효능감 제고에 다양한 시도가 필요함을 알 수 있었다. 또한 창업경험유무가 창업실패관련 지각된 혜택과 창업자기효능감 사이를 조절하므로 창업경험이 있는 창업자에 창업지원 사업의 유용성을 집중적으로 홍보할 필요가 있음을 알 수 있었다. 위와 같은 연구의 결과는 창업지원 관련 정책효과 제고를 위한 홍보방안 등에 대한 실무측면에서의 시사점을 제공한다.