• 시스템엔지니어링학술지
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• 제15권2호
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• pp.47-56
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• 2019

Although the weapon systems are becoming more diverse and complex, they are progressing in a short development period and a longer test and evaluation period. The more difficult the given environment is, the more efforts and performance of quantitative target values can be made by development agencies to carry out stable projects. However, these target values of the Integrated Logistics Support are not specified in the requirements and being set during the system development phase. In this paper, application of MOEs, MOPs and TPMs for ILS are presented and provided the basis for carrying out systematic Verification & Validation activities. As a result that MOEs of the ILS were chosen as Availability and MOPs as Mission Reliability, Logistics Reliability, Maintainability and Supportability and TPMs as MTBF, MTBCF, MTTR and so on. In particular, it is appropriate tailoring and apply the TPMs considering the cost, schedule, scope of work and characteristics of the project.

• 마이크로전자및패키징학회지
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• 제24권4호
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• pp.9-17
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• 2017

In these days, MEMS (micro-electro-mechanical system) devices become the crucial sensor components in mobile devices, automobiles and several electronic consumer products. For MEMS devices, the packaging determines the performance, reliability, long-term stability and the total cost of the MEMS devices. Therefore, the packaging technology becomes a key issue for successful commercialization of MEMS devices. As the IoT and wearable devices are emerged as a future technology, the importance of the MEMS sensor keeps increasing. However, MEMS devices should meet several requirements such as ultra-miniaturization, low-power, low-cost as well as high performances and reliability. To meet those requirements, several innovative technologies are under development such as integration of MEMS and IC chip, TSV(through-silicon-via) technology and CMOS compatible MEMS fabrication. It is clear that MEMS packaging will be key technology in future MEMS. In this paper, we reviewed the recent development trends of the MEMS packaging. In particular, we discussed and reviewed the recent technology trends of the MEMS bonding technology, such as low temperature bonding, eutectic bonding and thermo-compression bonding.

• 품질경영학회지
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• 제49권3호
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• pp.255-268
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• 2021

Purpose: We sought to understand why a high-speed rotating projectile featuring a fuze-and-body assembly sometimes exhibited airburst, and we intended to improve the flight stability by eliminating airburst. Methods: We performed characteristic factor analysis, structural mechanics modeling, and dynamic modeling and simulation; and we scheduled firing tests to discover the cause of airburst. We used a step-by-step procedure to analyze the reliability function for selecting the bonding force standard that prevents airburst. Results: The 00MM high-speed rotating projectile features a fuze bonded to a body assembly; the bonding sometimes can break on firing. The resulting contact force, vibration and roll damping during flight generated yaw. Flight became unstable; fuze operation triggered an airburst. Our reliability test improved the bonding force standard (the force was increased). When the bonding force was at least the minimum required, a firing test revealed that airburst/flight instability disappeared. Conclusion: Analysis and identification of the causes of flight instability and airburst render military training safer and enhance combat power. Ammunition must perform as designed. Our method can be used to set standards that improve the performances of similar types of ammunition.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.15-22
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• 2022

The Tactile Internet technology is considered as the evolution of the internet of things. It will enable real time applications in all fields like remote surgery. It requires extra low latency which must not exceed 1ms, high availability, reliability and strong security system. Since it appearance in 2014, tremendous efforts have been made to ensure authentication between sensors, actuators and servers to secure many applications such as remote surgery. This human to machine relationship is very critical due to its dependence of the human live, the communication between the surgeon who performs the remote surgery and the robot arms, as a tactile internet actor, should be fully and end to end protected during the surgery. Thus, a secure mutual user authentication framework has to be implemented in order to ensure security without influencing latency. The existing methods of authentication require server to stock and exchange data between the tactile internet entities, which does not only make the proposed systems vulnerables to the SPOF (Single Point of Failure), but also impact negatively on the latency time. To address these issues, we propose a lightweight authentication protocol for remote surgery in a Tactile Internet environment, which is composed of a decentralized blockchain and physically unclonable functions. Finally, performances evaluation illustrate that our proposed solution ensures security, latency and reliability.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.124-132
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• 2018

This paper presents a shelf life assessment for K-1 military gas masks in the Republic of Korea using test data of Chemical Materiels Stockpile Reliability Program(CSRP). For the shelf life assessment, over 2,500 samples between 2006 and 2015 were collected from field tests and analyzed to estimate a probability of proper and improper functionality using Bayesian estimation. For this, three stages were considered; a pre-processing, a processing and an assessment. In the pre-processing, major components which directly influence the shelf life of the mask were statistically analyzed and selected by applying principal component analysis from all test components. In the processing, with the major components chosen in the previous stage, both proper and improper probability of gas masks were computed by applying Bayesian estimation. In the assessment, the probability model of the mask shelf life was analyzed with respect to storage periods between 0 and 29 years resulting in between 66.1 % and 100 % performances in accuracy, sensitivity, positive predictive value, and negative predictive value.

• 설비공학논문집
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• 제19권1호
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• pp.86-93
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• 2007

The PEM (polymer electrolyte membrane) fuel cell is one of the promising fuel cell systems as a new small power generating device for automobiles and buildings. The optimal design of cooling plates installed between MEA (membrane electrode assembly) is very important to achieve high performance and reliability of the PEMFC because it is very sensitive to temperature variations. In this study, six types of cooling plate models for the PEMFC including basic serpentine and parallel shapes were designed and their cooling performances were analyzed by using three-dimensional fluid dynamics with commercial software. The model 3 designed by revising the basic serpentine model represented the best cooling performance among them in the aspect of uniformity of temperature distribution and thermal reliability, The serpentine models showed higher pressure drop than the parallel models due to a higher flow rate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.398-399
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• 2008

Enhanced performances of high temperature superconducting (HTS) cable attract tremendous interests of the power utility. However, the reliability issue as the power system is still in controversy. To verify the reliability of HTS cable, 22.9 kV HTS cable system with the specification of 100 m length, 50 MVA capacity, and open refrigeration cooling system was laid on Gochang power testing center of KEPCO in 2006. During the test period, the current transport characteristics, the fundamental function of power cable, have been monitored and investigated precisely. In this paper, the heat loss and AC loss measured at various current load conditions are described and discussed.

• 경영과학
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• 제30권3호
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• pp.33-54
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• 2013

The purpose of this study is to examine the relationships between Product Quality (Popularity, Playfulness) and Information Quality (Informativeness, Reliability), System Quality (Ease of Use, Security), Trust and Continuance Intention in Smart Phone Application Market. To identify these affecting relationships, the secondary data or past studies were collected and theoretically arranged. I made the theoretical proposed model to explain the relationships between the constructs, identify the operational definitions and 13 Hypotheses were established, there was executed the survey of 250 customers of Smart Phone Application Market. Using the collected data, previous performances to confirm the construct validity and internal consistency by Cronbach's a was executed and Partial Least Square Analysis to confirm the hypotheses in proposed model was conducted using the Smart-PLS Software. As the result of test that make the relations of used variables clear, we can get the conclusion as followings; First, Product Popularity has the positive effect on Informativeness, except reliability of Information. Second, it was significantly tested the effect on the Ease of use and Security by Product Playfulness. Third, Informativeness and Ease of Use, Security of App Store have the significantly positive effects on the Users' Trust directly. From the empirical test, I suggest the strategic advices in App Store Companies. To increase the Users' Continuance Intention or Loyalty, it would be developed that a variety of methods and ways to raise the Product Popularity and Playfulness, Informativeness, Ease of Use and Security of App Store. It is necessary for sticking the Users to raise the positive trust building and Continuance Intention.

• 한국지진공학회논문집
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• 제12권2호
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• pp.9-22
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• 2008

이 논문에서는 구조물의 내진성능 향상을 위한 방법으로서 구조부재 및 수동형 감쇠기의 통합최적설계기법을 제시한다. 이는 구조부재 및 감쇠기의 최적배치를 다루는 최적화기법이다. 통합시스템의 최적설계를 위하여 다목적최적화기법을 도입하고, 이를 보다 효율적으로 다루기 위하여 목표신뢰성 제한조건을 갖는 다목적최적화문제로 재구성하였다. 수치해석 예제를 통하여 다양한Pareto 최적해를 제시하였으며, 이들이 기존 설계방법에 상응하는 순차적 설계방법 및 가중합방법에 따른 단일목적함수 최적화방법을 포괄함을 검증하였다. 여러 Pareto 최적해로부터 강성 및 감쇠장치의 사용량을 달리하는 3가지 대표설계안을 선택하고 이들의 내진성능을 다양한 지진하중에 대하여 비교 분석하였다. 이로부터 제시하는 방법이 구조물의 내진성능 향상을 위한 설계방법으로서 효율적으로 적용될 수 있을 것으로 기대된다.

• 한국간호교육학회지
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• 제22권4호
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• pp.549-558
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• 2016

Purpose: The purpose of this study was to develop and validate a Nursing Competency Scale in Simulation (NCSS) for nursing students. Methods: A preliminary version of the NCSS of 14 items was derived from the literature. A panel of seven experts reviewed the preliminary version for content validation and developed 15 items scale. A convenient sample of 195 nursing students completed the survey and two evaluators measured the performances of nine teams in a simulation scenario with NCSS. The data were analyzed using exploratory factor analysis, descriptive statistics, independent t-test and Cronbach's alpha. Intraclass correlation coefficient (ICC) was used in order to estimate the degree of inter-rater reliability. Results: An exploratory factor analysis demonstrated that two factor structures of the NCSS explained 51.1% of the total variance. Two factors were named psychosocial skills and cognitive and psychomotor skills. The mean scores of NCSS between third and 4th grade were significantly different providing support for its known-group validity. Cronbach's alpha was .90 and ranged from .79 to .88. The overall ICC for inter-rater agreement was 0.89 (95% CI 0.03 to 0.98). Conclusion: This scale shows preliminary evidence for validity and reliability. It could be a useful instrument for measuring learning outcome in simulation for nursing students' clinical competency.