• Journal of the Korean Institute of Gas
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• 제16권4호
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• pp.8-15
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• 2012

The GO-FLOW methodology is capable of assessing system reliability. It models the system into a GO-FLOW chart with signal lines and operators and assesses the reliability of system by assessing the GO-FLOW chart sequential. But, as it models one component of system into several operators, the GO-FLOW chart which is different from the system flow diagram be modeled. Also, as it models the real operation time into "time point", it is hard to assess the reliability change according to the real operation time. Therefore, in this paper, the new GO-FLOW methodology which use the function(success/failure) of system components has been developed. It can assess the successful operating probability of system, regardless of the operating status of components. As it models one component of system into one operator, the GO-FLOW chart which is similar the system flow diagram can be modeled. Also, it is able to easily assess the successful probability of system according to the real operation time using the time in the operators.

• The Journal of Korean Institute of Next Generation Computing
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• 제13권5호
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• pp.51-70
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• 2017

The reliability of broadcasting over vehicular ad hoc networks (VANETs) is one of the most critical factors for driving safety applications. There exists limitations to improve the reliability of broadcast transmissions in saturated VANETs where previous proposals in literature tackle the problem by heuristically adapting the size of the contention window (CW). This paper considers improving the reliability by proposing a new probability model based on the counting methods of permutations and combinations, which counts all the possible cases of broadcast failures in a single-hop broadcast transmission for a given CW. From the model, we calculate the best CW size given the number of contention nodes, which significantly improves the reliability and satisfying the timely dissemination of emergency broadcasting messages. Through extensive VANET simulations with varying densities, we show that our model maintains near 100 percent success rate for single-hop broadcast as well as multi-hop broadcast (e.g. 40 hops) and achieves minimal broadcast delay.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.381-386
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• 2014

A highly reliable safety class controller for NPPs (Nuclear Power Plants) is mandatory as even a minor malfunction can lead to disastrous consequences for people, the environment or the facility. In order to enhance the reliability of a safety class digital controller for NPPs, we employed a diversity approach, in which a PLC-type controller and a PLD-type controller are to be operated in parallel. We built and used structured testbenches based on the classes supported by UVM for functional verification of the PLD-type controller designed for NPPs. We incorporated a UVM register model into the testbenches in order to increase the controllability and the observability of the DUT(Device Under Test). With the increased testability, we could easily verify the datapaths between I/O ports and the register sets of the DUT, otherwise we had to perform black box tests for the datapaths, which is very cumbersome and time consuming. We were also able to perform constrained random verification very easily and systematically. From the study, we confirmed the various advantages of using the UVM register model in verification such as scalability, reusability and interoperability, and set some design guidelines for verification of the NPP controllers.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.344-352
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• 2019

Marine production strings are continuously affected by unstable internal fluid during operation. In this paper, the structural governing equation for marine production string self-induced vibration is constructed. A finite element analysis model is established based on Euler-Bernoulli theory and solved by the Newmark method. Furthermore, based on reliability theory, a self-design procedure is developed to determine the operability envelope for marine production string self-induced vibration. Case studies show: the response frequency of the production strings is consistent with the excitation frequency under harmonic fluctuation and mainly determined by the first-order natural frequency under stochastic fluctuation. The operability envelope for marine production string self-induced vibration is a near symmetrical trapezium. With the increasing of natural gas output, the permissible fluctuation coefficient dramatically decreases. A reasonable centralizer spacing, increasing top tension, and controlling natural gas output are of great significance to the risk control in marine production string operation.

• Journal of the Korean Society of Clothing and Textiles
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• 제44권2호
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• pp.209-223
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• 2020

This study examined consumers' perceived anxiety regarding how safe the clothing and lifestyle products are as well as influencing factors. Data was collected using a self-ministered online survey of 1,126 adult consumers. The results of this study showed that consumer anxiety about chemicals and hygiene product safety had a greater impact on the anxiety perception of general safety than clothing and beauty products. It was confirmed that the reliability of information source (government agency, mass media, expert group, and internet community/blog) varies depending on the level of consumers' overall safety anxiety. The study also found the effect of consumers' subjective perception of health on safety anxiety about clothing and lifestyle products. Further, the moderating effect of age in the research model was confirmed. This result can be a useful guide to marketing communication for developing consumer safety-related policies to reduce consumer anxiety. The information will also help consumers make informed decisions that lead to safe and sustainable consumption.

• Perspectives in Nursing Science
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• 제10권2호
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• pp.133-140
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• 2013

Purpose: This study aimed to investigate the perspective of consumers in healthcare services regarding patient safety. Methods: The study was a descriptive study using a self-reported questionnaire. The questionnaire was based on the Senior Empowerment and Advocacy in Patient Safety (SEAPS) questionnaire, which was designed to assess patient safety health beliefs. The survey was conducted online and a convenient sample of 302 adults participated in total. The reliability of the measurement (Cronbach's ${\alpha}$) was 0.758 in attitude (ATT), 0.546 in out-come efficacy (OE), 0.757 in self-efficacy (SE), and 0.703 in behaviors (BEH). Results: The average patient safety awareness score of the healthcare service consumers was 2.72 (ATT), 2.91 (OE), 2.87 (SE), and 2.27 (BEH). Our analysis indicated that there were no differences in ATT, BEH, or SE by gender, age, or education level. However, in OE and the total score of the four subscales, there were significant differences by age and gender. Correlations were identified between BEH and SE (r=0.409, p<.01), BEH and OE (r=0.202, p<.01), ATT and SE (r=0.358, p<.01), and OE and SE (r=0.241, p<.01). Conclusion: This study measured consumer perspectives concerning patient safety. The findings demonstrate the need for developing a measurement tool to assess consumer's perception of patient safety, considering Korean healthcare system and cultural context.

• Journal of Drive and Control
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• 제17권4호
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• pp.141-151
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• 2020

The aim of this study was to analyze the safety factor of range-shift gear pairs on multi-purpose agricultural implement machinery for an optimal design of a transmission system. Gear-strengths such as bending and contact stress and safety factors were analyzed under three load conditions: an equivalent engine torque at plow tillage, a rated engine torque, and the maximum engine torque. Root and contact safety factor were calculated to be 3.88, 5.14, 2.24, 2.11, 2.21, 0.99 and 0.78, 0.94, 0.65, 0.68, 0.84, 0.85, respectively, under equivalent engine torque condition at the plow tillage. The root and contact safety factor were calculated to be 1.91, 2.53, 1.10, 1.04, 1.07, 0.48 and 0.55, 0.66, 0.46, 0.48, 0.59, 0.59, respectively, under rated engine torque condition. The root and contact safety factor were calculated to be 1.60, 2.11, 0.92, 0.87, 0.90, 0.40 and 0.51, 0.61, 0.42, 0.44, 0.54, 0.54, respectively, under the maximum engine torque condition. The multi-purpose agricultural implement machinery could be conducted under plow tillage operation. However, gear specifications for tooth surface need modification because the gear surface would be broken at all driving conditions as safety factors are lower than 1.

• Journal of Industrial Technology
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• 제3권
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• pp.53-63
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• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; Pf=M/N N : Total number of trials M : Total number of failures Some of the conclusions derived from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The F3/F2 ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. In cases that strength parameters are assumed to be normal variated and beta variated, the relationships between safety factor and the probability of failure are fairly consistent, regardless of the shape of the 3-D shear surface and the slope. 4. As the c-value is increased, the probability of failure for the same safety factor is increased and as the ${\phi}-value$ is increased, the probability of failure for the same safety factor is decreased.

• Journal of the Korea Safety Management & Science
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• 제16권4호
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• pp.123-131
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• 2014

Modern weapon systems are getting more complex in terms of the functionality and also the conditions on the environment and range in which they are deployed and used. Therefore, many development programs can easily be exposed to a variety of risks, resulting in delayed schedules and cost overrun. As such, effective means are necessary to keep the defence budget at an affordable level while competitive edges on technological aspects are retained. As one way to meet those need, modeling and simulation (M&S) methods have widely been used, particularly in the test and evaluation (T&E) process for weapon systems development. The result of M&S-based systems development should be evaluated by the verification, validation & accreditation (VV&A) process to assure keeping reliability at a desired level. On the other hand, due to the explosiveness, the weapons systems development naturally requires to consider safety issues in both the T&E and operational periods. The purpose of this paper is to improve the VV&A process by reflecting the safety requirements therein. To do so, the VV&A process has been analyzed and graphically modeled first and then safety elements have been incorporated effectively. The use of the improved process in the war ships development has also been discussed. Based on the process proposed and the consequent database constructed, the target system can be expected to benefit from reducing development risks while assuring systems safety.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권7호
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• pp.1246-1252
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• 2006

Recently, customers interest increase in the agricultural product safety when receiving the many information about food problem due to the development of media. Such amid, domestic agricultural environment don't have a system that safety certification of agricultural product. At this rate, domestic agricultural products will decrease the competitive power and apprehend by the giving a market to foreign agricultural product. In this paper, we designed and implementation of AIGT system for the improvement of agricultural environment to producing the agricultural product safety and customers' reliability increase to offering clear information. Also, we defined the right data structure for agricultural environment. The monitoring and video conference are imported for efficient improvement of environment.