• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.682-689
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• 2014

Due to explosive growth of mobile data traffic, many kind of techniques based on small cell is proposed as solution for phenomenon. However, those techniques essentially demands increase of backhaul capacity and causes performance degradation if not satisfied. Based on that, the approach applying the storage capacity in place of backhaul capacity, which is known as femto-caching, is proposed to reduce data downloading delay of users in system. In this paper, we expanded previous research by proposing file placement strategy with distribution of user position, which is more practical scenario. Simulation results verify that our proposed scheme has better performance gains mainly because when coverage of helpers are overlapped, users get more opportunity to connect various helpers which enables users to download a variety kind of files from helpers, not base station.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.309-314
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• 2006

The amount of transshipment cargoes had been increased in Korea ports due to the rapid Chinese economic growth and the lack of facilities in Chinese ports. Recently, this increasing rate of transshipment cargoes in Korean ports is declining because Shanghai port is developing and establishing direct calls and shipping lines to China. Therefore, it is considered a big obstacle for Busan port to be a hub port. Due to that fact, an innovative development of domestic ports is necessary in order to overcome this obstacle. This paper analyzes the cargo O/D between Busan port and Japanese ports, and logistics costs are analyzed when Japanese cargoes are transshipped in Busan port.

• Journal of the Korean Institute of Gas
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• v.20 no.1
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• pp.7-12
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• 2016

Natural gas liquefaction process is essential to transport natural gas for long distances. Lots of compressors in this process are needed and the energy for these compressors can be supplied by drivers. Total driver cost can be changed by selecting various drivers. This study focused on the minimization of the driver cost to provide the energy to the compressors. Moreover, scenarios, extracting velocity is changed during whole operating period, are set with considering gas well capacity. The mathematical model was established by considering trade off relationship between the capital cost and the operating cost of the turbines. The model also considers the life time of the driver equipments. As the result, the driver cost of the optimized case was reduced by 6.4% than the base case.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.11-21
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• 2012

It is indispensable that aircrafts in electrical warfare settings endeavour to improve their survivability by selecting optimal countermeasures against threats. In this paper, we model the successful probabilities of aircraft survivability equipments that remove threats encountered, and also propose a framework for the aircrafts to autonomously decide their countermeasures. And then, we design the operational effectiveness of the aircraft survivability equipments, and quantitatively formulate the operational effectiveness into the form of reduction in lethality (RL). We actually show how the operational effectiveness can be computed in simulated example scenarios. To verify our framework proposed in this paper, we experimented with the successful probabilities of aircraft survivability equipments and the autonomous decision-making against threats in various electronic warfare settings. In the experiments, it turns out that our agents outperform the agents that randomly choose their countermeasures, which is 12% more efficient in their performance.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.283-288
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• 2019

This study investigated how consumer's uncertainty avoidance affect purchase deferral intention when purchasing high-involved products (i.e. laptops) in online shopping, and we looked at whether utilitarian/hedonic consumption value has a moderating effect in this relationship. Results showed the higher the uncertainty avoidance, the higher the deferral intention. Also, only the utilitarian consumption value had moderating effect in this relationship. This means that in an information overload situation like online shopping, consumers are more likely to delay their purchase intention when they have more uncertainty avoidance. Thus, to prevent this purchase delay, marketers should selectively present relative product information, strategically emphasize the importance of certain product attribution to reduce consumers' uncertainty of the product or highlight the utilitarian values of product attributes that are expected to have a significant impact on decision making.

• Journal of the Korea Society for Simulation
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• v.28 no.3
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• pp.57-63
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• 2019

This study suggests the level of guaranteed reserves that should be accumulated in order to provide guaranteed interest contracts to pension members. To calculate the guaranteed reserve, this study employs the method using variable insurance contracts with guaranteed interest options. The average return of three major pensions (national pension, private teacher's pension, civil servants pension) funds, from 2010 to 2018, is set as the target rate of return and then we establish 0%, 1.0%, 1.5% and 2.0% each as our minimum guaranteed returns for their respective guaranteed reserves. Our results firstly show that gaps between each guaranteed reserves are increasing as times goes on. Second, the probability of shortfall reserve is on the decrease as the pension fund is mature. Conclusively, a long-term conservative balance between risk and return is one of the best investing strategies in pension funds providing the guaranteed interest.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.401-409
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• 2021

This study was performed to identify the difference in nursing process competency, critical thinking disposition and self-efficacy after applying virtual reality simulation education. The data were collected from 31 nursing college students using URL from February to April 2021 and analyzed SPSS 22.0. The pretest and posttest result of each group showed statistically significant improvements in nursing process competency(t=-3.776, p=.001), critical thinking disposition(t=-3.608, p=.001) and self-efficacy(t=-3.580, p=.001). As a result of this study, it was found that virtual reality simulation education improve nursing process competency, critical thinking disposition and self-efficacy of nursing students. Therefore, virtual reality simulation education will be the basis for preparing effective clinical practice education strategies for nursing students. It is suggested to have follow-up studies on virtual reality simulation education and various scenarios should be developed.

• Journal of Korea Water Resources Association
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• v.54 no.9
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• pp.705-718
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• 2021

Climate change has a significant impact on vegetation growth and terrestrial ecosystems. In this study, the possibility of ecological drought was investigated using satellite remote sensing data. First, the Vegetation Health Index was estimated from the Normalized Difference Vegetation Index and Land Surface Temperature provided by MODIS. Then, a joint probability model was constructed to estimate the possibility of vegetation-related drought in various precipitation/evaporation scenarios in forest areas around 60 major ASOS sites of the Meteorological Administration located throughout Korea. The results of this study show the risk pattern of drought related to forest vegetation under conditions of low atmospheric moisture supply or high atmospheric moisture demand. It also identifies the sensitivity of drought risks associated with forest vegetation under various meterological drought conditions. These findings provide insights for decision makers to assess drought risk and develop drought mitigation strategies related to forest vegetation in a warming era.

• Convergence Security Journal
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• v.18 no.3
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• pp.61-68
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• 2018

As the digital broadcasting era settled in, the TV, which was only used to watch broadcast programs, developed as a medium for operating various data services. This means that an environment, in which the viewers' TV usage behavior can be changed from a passive attitude to an attitude of actively consuming the media, has been established. Since the advertising market is an industry that is heavily influenced by changes in the media, these changes causes changes in the form of advertising and the advertising consumption behavior of viewers. In this environment, the broadcasting industry needs to think about the new growth strategy that links the possibility of data service with the advertisement market. In this study, we designed a data service that provides supplementary information of an ID advertisement, which has the weakness of short exposure time and shortage of information expression space. Specifically, we have designed the usage scenario and user interface of the data service and developed a method, based on the international digital broadcasting standard DV B, that provides the supplementary information defined by the type of ID advertisement to the data service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1209-1215
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• 2019

Communication is an important factor for nurses to lead successful nursing interventions by establishing therapeutic relationships with the subjects and cooperative relationships between the various occupations. The purpose of this study was to develop a communication education program to nurse college students to improve communication skills among medical professionals and to analyze the effects of the program. The subjects of this study were 54 students in the 4th grade of P nursing. The results of this study showed that there was a significant difference between the subjects' communication clarity(t=-7.75, p<.001) and self-leadership (t=-4.43, p<.001). Satisfaction with communication increased after the training but there was no significant difference (t=-1.22, p=.226). In conclusion, communication program using SBAR has a positive effect on clarity of communication and self-leadership of nursing students, and it is necessary to develop continuous education that can develop various scenarios and repeat training.