• International Journal of Reliability and Applications
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• v.17 no.1
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• pp.21-49
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• 2016

Many mechanical, electrical and electronic products have more than one performance characteristics (PCs). For example the performance degradation of rubidium discharge lamps can be characterized by the rubidium consumption or the decreasing intensity the lamp. The product may degrade due to all the PCs which may be independent or dependent. This paper deals with the design of optimal bivariate step-stress partially accelerated degradation test (PADT) with degradation paths modelled by gamma process. The dependency between PCs has been modelled through Frank copula function. In partial step-stress loading, the unit is tested at usual stress for some time, and then the stress is accelerated. This helps in preventing over-stressing of the test specimens. Failure occurs when the performance characteristic crosses the critical value the first time. Under the constraint of total experimental cost, the optimal test duration and the optimal number of inspections at each intermediate stress level are obtained using variance optimality criterion.

• Journal of the Korea Society for Simulation
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• v.23 no.2
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• pp.7-15
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• 2014

System operational performance analysis for wire-guided torpedo is intended to provide technical analysis data for requirements analysis and development, which, as a consequence, supports the requirements definition activity for systems engineering. Technical approach and analysis example are presented including problem definition, formulation, modeling, simulation and analysis results that are applied to the on-going Next Generation Torpedo project.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.87-101
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• 2021

Required Operational Capability(ROC), which means the performance of a weapon system, is determined when estimating the requirements of a new weapon system. It is very important to define the ROC as it has a decisive influence from acquisition of a weapon system to tactical operation. In this study, we propose a simulation methodology to verify the ROC of the Para-Observation Munition(POM), a newly developed weapon system. To this end, we propose a discrete-event simulation model that takes main performance of the weapon system constituting the ROC and environmental factors that affect performance of the weapon system as input values, and outputs operational effect as a result value. It describes various simulation logic required to implement a simulation model, and explains how to verify ROC using various simulation results such as sensitivity analysis. POM is a weapon system that does not have a similar one and that is difficult to directly utilize the military analysis model. This study can be used as a methodology to analyze the ROC and predict operational effects of weapon systems such as POM.

• Management & Information Systems Review
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• v.13
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• pp.27-47
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• 2003

The strategic usages of IT(Information Technology) can convey important competitive advantages with an operational productivity. For this reason, many firms have heavily invested in IT and computing power. However, many companies were getting expected results by IT investment, but some companies had to be satisfied with a poor results. The question of whether or not benefit lead to expected performance is not easy to answer. The purpose of this study was to investigate the relationship among IT strategy, IT investment, and IT performance to resolve this problem. The 147 questionnaire responses completed by IS managers in manufacturing sector was conducted for a test of research hypothesis. ANOVA was used to investigate the relationship among three constructs and six factors. An operational performince of fitted group between IT strategy and IT investment was higher than not fitted group(H1). And also an competitive performance of fitted group between IT strategy and IT investment was higher than not fitted group(H2). The study shows a positive relationship between IT strategic orientation, IT investment direction, and performance of IT. The research results provide empirical evidence that supports the research hypothesis that closer fit between IT strategies and IT investment directions does lead to increase operational and competitive performance of IT.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.3
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• pp.75-85
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• 2024

Airpower is a crucial force for suppressing military threats and achieving victory in wars. This study evaluates newly introduced fighter forces, considering factors such as fighter performance and power index, operational environment, capacity of each airbase, survivability, and force sustainment capability to determine the optimal deployment plan that maximizes operational effectiveness and efficiency. Research methods include optimization techniques such as MIP(mixed integer programming), allocation problems, and experimental design. This optimal allocation mathematical model is constructed based on various constraints such as survivability, mission criticality, and aircraft's performance data. The scope of the study focuses the fighter force and their operational radius is limited to major Air Force and joint operations, such as air interdiction, defensive counter-air operations, close air support, maritime operations and so on. This study aims to maximize the operational efficiency and effectiveness of fighter aircraft operations. The results of proposed model through experiments showed that it was for superior to the existing deployment plan in terms of operation and sustainment aspects when considering both wartime and peacetime.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.127-134
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• 2009

RAM(Reliability, Availability, Maintainability) is important performance factor to keep combat readiness and optimize operational and maintenance cost of weapon systems. This paper discusses the method to establish RAM for combat readiness by using field failure data from similarity equipments. Operational availability is estimated from a binomial distribution function of user's operational conditions such as combat readiness preservation probability, operational rate, operational availability and total number of equipment. Reliability and maintainability is estimated from field failure data from similarity equipment to accomplish operational availability. The effectiveness of established RAM is verified through analysis of combat readiness preservation probability and mission reliability. A case study of weapon system illustrates the process of the proposed method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.1
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• pp.11-23
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• 2018

This paper investigated relationship among internal as well as external motive to receive the ISO 13485 certification, countermeasure to the certification examination, active reception/execution level of the certification, and operational as well as financial performance of the medical device related enterprises in South Korea which received and are maintaining the ISO 13485 certification. SEM (structural equation model) and related analyses using AMOS 21.0 and SPSS 21.0 have been applied to verify the hypotheses of the research. Result of the research showed that internal as well as external motive for certification positively(+) affects active reception/execution level of the certification as well as countermeasure to the certification examination. The reception/execution level of the certification also positively(+) affects on the operational as well as financial performance of the certified enterprises. However, countermeasure to the certification examination was found out to negatively(-) affects the active reception/execution level of the certification and we can interpret that relatively more countermeasure to the certification examination burdens the employees of the enterprise, causing them to be less active on the reception/execution level of the certification. This research found that an enterprise's operational/financial performance improves when an enterprise introduces the ISO 13485 certification standard spontaneously on the purpose of improving its system and the certification system is applied to the enterprise actively, not passively. This research emphasizes the need to recognize the difference of the level of active reception implication among members of an enterprise according to the motive of introduction of the certification system.

• International Journal of Quality Innovation
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• v.6 no.1
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• pp.24-34
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• 2005

This research topic evaluates the effectiveness and importance of environmental protection in the 21st century in light of the increasing demand on the earth's natural resources and the pressures on economic and industrial development to provide dynamic power. As the world and our fellow citizens become more conscious of environmental protection, companies are under greater pressure whilst pursuing economic growth. Therefore, domestic manufacturers have been devoting efforts to promote environmental management. This research conducts survey using questionnaires on the operational performance of the manufacturers who have ISO 14000 series accreditation and certification. The survey considers five dimensions/functions within a manufacturer, financial management, human resources management, production management, and marketing management. A total of 35 indices are used for analysis of the effects that the location, history, industry, number of employees, amount of capital, and revenue may have on the performance. This research targets the manufacturers approved of ISO 14000 series certification by Environment Administration Association. The statistical methods deployed are descriptive statistics, T-test, and single factor analysis of variance used for analysis. The conclusions reveal that a certain level of performance has been achieved in every dimension. After T-test, all the indices have reached a significant level. The indications are that ISO 14001 benefits all manufacturers the level of benefits however varies from company to company.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.20-37
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• 2002

In this paper, we studied the purpose of this paper is like that; the first one is to find the factors associated with operational strategy by variable website types classified into information-providing type, product-providing type and service- providing type by user approach purposes. The second one is to propose the successful operational strategy through analyzing the factors affecting the financial and non-financial performance of websites. A framework of research model including above factors is developed and tested statistically. The data are collected from Internet website experts of 80 Korean firms through survey. The main results of this research are as follows. First, in information-providing websites, the community factor is regarded as the most important factor But for the Improvement of the performance, not only community factor but also user interface, customization, total quality and playfulness factors should be regarded as important factors equally. Second, in product-providing websites, customization, total quality and visual design factors are regarded as important factors. But for the improvement of the performance, community and visual design factors should be regarded as important factors. Third, in service-providing websites, user interface, customization and community factors should be regarded as important factors in order to improve the performance.

• Asia pacific journal of information systems
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• v.10 no.4
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• pp.1-20
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• 2000

Electronic Data Interchange(EDI) has the potential to improve business operations by expediting the exchange of business documents. It will also provide substantive operational and strategic benefits to the trading firms. However, the successful implementation of EDI systems requires the mutual trust and cooperation between the trading firms. The extent of EDI diffusion and performance depends on inter-organizational, intra-organizational, as well as innovation factors. Researches based on the sociopolitical process framework in the use of IT, organizational theory, resource dependence theory, and innovation diffusion theory have identified 3 inter-organizational variables(transaction climate, dependence, external IS expert support) and 4 intra-organizational variables(strategic IS planning, infrastructure, top management support, education/training,), and 3 innovation variables(compatibility, relative advantage, cost) that affect EDI diffusion. In this study, a multi-dimensional measure on EDI diffusion has been developed to capture the external and internal integration. Then, the influence of these 10 variables on the extent to which the EDI adopting firms pursue diffusion has been examined. Whether more diffusion leads to superior performance has also been studied. International trade managers from 107 firms in the trade industry participated in a field survey. The results based on a structural equation model(SEM), developed using AMOS, provide quite a strong support for the hypothesized relations. Both education/training and IT infrastructure influenced external and internal diffusion of EDI systems. Internal diffusion of EDI enables the adopting firms to improve operational and strategic performance, whereas external diffusion contributes only to operational performance.