• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.103-112
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• 2006

Priority-based network service has been widely adopted for the Internet traffic management in the context of IETF differentiated services, and computing optimal prices for such priority-based service is the key topic in many pricing literature. While the equilibrium analysis has been commonly used to this end, many have criticized the validity of the underlying assumption of equilibrium analysis that user utility functions are precisely known. In this paper, we propose a solution for bridging the gap between the existing theoretical work on optimal pricing and the unavailability of precise user utility information in real networks. In the proposed method, the service provider obtains more and more accurate estimates of user utility functions from the initial imprecise knowledge by iteratively changing the price of service levels and observing the users' decisions under the changed price. Our contribution is two-fold. First, we have developed a general principle for estimating the user utility functions. Second, we have developed a novel method for setting the prices that can optimize the extraction of the knowledge about user utility functions. The extensive simulation results demonstrate the effectiveness of our method.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.379-392
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• 2021

In recent years, vocational training has shifted away from lectures and practice-oriented methods in light of rising demand for project-based classes in which trainees can produce results while simultaneously receiving feedbacks from field experts from the industry. Therefore, this study aims to suggest a salient role of the project-based classes of enterprise-customized training programs, which private vocational training institutions regard as vital, by identifying demands from trainees or the actual beneficiaries of these programs. To this end, a written survey of the trainees' perception of the enterprise-customized training programs was conducted along with a qualitative analysis of open-ended questions. Specifically, we analyzed the overall satisfaction level of these classes, their contribution to employment, degree of meeting the expectations, and areas for improvements to ultimately derive significant implications.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1521-1527
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• 2019

Objective: To study the contribution of plant enzyme and microbial activities on protein degradation in silage, this study evaluated the nitrogen transformation dynamics during ensiling of non- and irradiated alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.). Methods: Alfalfa and red clover silages were prepared and equally divided into two groups. One group was exposed to ${\gamma}$-irradiation at a recommended dosage (25 Gky). Therefore, four types of silages were produced: i) non-irradiated alfalfa silage; ii) irradiated alfalfa silage; iii) non-irradiated red clover silage; and iv) irradiated red clover silage. These silages were opened for fermentation quality and nitrogen components analyses after 1, 4, 8, and 30 days, respectively. Results: The ${\gamma}$-irradiation successfully suppressed microbial activity, indicated by high pH and no apparent increases in fermentation end products in irradiated silages. All nitrogen components, except for peptide-N, increased throughout the ensiling process. Proteolysis less occurred in red clover silages compared with alfalfa silages, indicated by smaller (p<0.05) increment in peptide-N and free amino acid N (FAA-N) during early stage of ensiling. The ${\gamma}$-irradiation treatment increased (p<0.05) peptide-N and FAA-N in alfalfa silage at day 1, whereas not in red clover silage; these two nitrogen components were higher (p<0.05) between day 4 and day 30 in non-irradiated silages than the irradiated silages. The ammonia nitrogen and non-protein nitrogen were highest in non-irradiated alfalfa silage and lowest in irradiated red clover silage after ensiling. Conclusion: The result of this study indicate that red clover and alfalfa are two forages varying in their nitrogen transformation patterns, especially during early stages of ensiling. Microbial activity plays a certain role in the proteolysis and seems little affected by the presence of polyphenol oxidase in red clover compared with alfalfaa.

• Journal of Digital Convergence
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• v.16 no.11
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• pp.255-265
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• 2018

This study investigated what kind of message forms and information sources more effect according to SNS' type and use intensity. To this end, this study did experimental analysis using collected data by survey which manufactured message forms and situational contents of information sources. According to analysis results, the effect of message forms showed difference according to SNS' type and use intensity. Realistic message showed greater effect in interest-based SNS and high use intensity. Evaluative message showed greater effect in relation-based SNS regardless of use intensity. The effect of information sources showed difference according to SNS' type. Friend or college and knower showed greater effect in relation- based SNS, and company showed greater effect in interest-based SNS. In the case of use intensity, friend or college showed the greatest effect without difference. Such results can provide a practical contribution in planning SNS advertising strategy. Future Studies need to expand survey variously into SNS and subject.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.2
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• pp.196-213
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• 2019

This paper attempts to analyze the contribution of different socioeconomic factors such as income, age, gender, household composition, education and employment status etc. to the difference between the Capital and Non-Capital Regions in the net wealth inequality of household in Korea. To this end, a two-stage Oaxaca-Blinder type decomposition is employed regarding the regional gap in the inequality of net wealth based upon the Recentered Influence Function of the Gini index for 'the 2018 Household Finance and Living Conditions Survey.' Despite the shortcomings of the survey data on wealth, the findings reveal that regional differences in income, marriage status (divorce), job type (agriculture, forestry and fishery related, and technical and assembly), family type (multi-cultural) variables deepen the regional gap in the net-wealth inequality, but employment status (full-time), job type (administrative and specialized, and service sales), household size variables mitigate the gap, and that regional differences in life cycles play an offsetting role.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.127-133
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• 2019

A callable product is one of service derivatives using options to generate demand and reduce risk. This paper compares two booking admission controls for callable products, the online and the batch admission controls. To this end, the paper computes the optimal booking policy by using the backward dynamic programming and the stochastic optimization method. Intuitively, the provider should outperform under the batch control by utilizing demand information. The contribution of the paper is to show that the two controls are equivalent in terms of the booking strategy and the expected profit, which enables the provider to keep its current control method. The paper develops the closed-form solutions for the three fare classes. The future work is to extend the result to the model with complicated fare structures.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.179-188
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• 2019

This paper presents an experimental study to evaluate the effect of palm oil on the selected basic physical-chemical and geotechnical properties of kaolin. The experimental findings are further compared with literature outcomes investigating similar properties of fine grained soils subjected to contamination by different types of oils. To this end, palm oil was mixed with oven dried kaolin samples-aiding oil's interaction (coating) with dry particles first, in anticipation to emphasize the effect of oil on the properties of kaolin, which would be difficult to achieve otherwise. Oil content was limited to 40% by dry weight of kaolin, supplemented at intervals of 10% from clean kaolin samples. Observations highlight physical particle-to-particle bonding resulting in the formation of pseudo-silt sized clusters due to palm oil's interaction as evinced in the particle size distribution and SEM micrographs. These clusters, aided by water repellency property of the oil coating the kaolin particles, was analyzed to show notable variations in kaolin's consistency-measured as liquid and plastic limits. Furthermore, results from compaction tests indicates contribution of oil's viscosity on the compaction behavior of kaolin - showing decrease in the maximum dry unit weight (${\gamma}_{d,max}$) and optimum moisture content ($w_{opt}$) values with increasing oil contents, while their decrease rates were directly and inversely proportional in ${\gamma}_{d,max}$ and $w_{opt}$ values with oil contents respectively. Comparative study in similar terms, also validates this lower and higher decrease rates in ${\gamma}_{d,max}$ and $w_{opt}$ values of the fine grained soils respectively, when subjected to contamination by oil with higher viscosity.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.65-75
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• 2019

While the quantitative results of research on emotional labor that has been studied in Korea has never been minimal, most of the researches that have been conducted are limited to generalization by empirical analysis studies limited to single industry cases. A more integrated approach is needed in addition to quantitative research methods in order to research results that can be generalized when the importance and interest in emotional labor is increasing. Therefore, this study analyzed in-depth 112 articles published in the field of management in Korea, which were searched under the keyword emotional labor, using KCI from 2008 to 2018. To this end, the research trends of emotional labor, such as the concept, and the method of analysis, were reviewed from various aspects and presented future research directions. This research result attempted to contribute not only to academic contribution to emotional labor but also to the expansion or integration of the application area to the internal mechanisms of emotional labor.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.166-179
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• 2020

The purpose of this study is to explore and analyze what has changed in Seoul National University (SNU) since its incorporation, focusing on the perceptions and experiences of its internal members. To this end, semi-structured interviews were conducted with members of SNU, professors, staff, and students. The interview results were presented by categorizing them into changes in the overall evaluation of the incorporation, positive and negative changes, education, research, social contribution, and operating system. Overall, with regard to the changes after incorporation, the members of SNU showed a common perception that it was difficult to feel the change or that there was little change. As for positive changes, they mentioned the expansion of university finances, increased autonomy in operation, and improved responsiveness to environmental changes. As for negative changes, they mentioned the ambiguity of SNU's legal status, and the excessive increase of direct and aggressive influence from outside. In the last part, the main findings were summarized and their meaning and implications were discussed.

• Korea Journal of Hospital Management
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• v.25 no.4
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• pp.60-75
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• 2020

Purpose: This study aims to develop a cost model for NRP (Nursing Residency Program) operation and ultimately provide evidence for financial factors for NRP operation in the future by simulating a cost model. Methodology: This study developed a model for the NRP education cost calculation model based on the review of Hansen's model, which has systematically reported on the development and operation of NRP, and discussions with nursing education experts at a university-affiliated hospital. With the simulation, it was intended to predict nurses' supply and demand in the long term and to calculate changes in long-term education costs. Findings: Firstly, turnover model, term model, cost model necessary for calculating a model for the NRP education cost calculation model was set up. Secondly, the simulation showed the following results; 1) the proportion of newly graduated nurses less than 5 years of working decreases gradually over time, which will make the composition of nurses more balanced. 2) In the first year of the partial introduction of NRP, the cost of training new nurses was about 2.1 times higher than before. After the introduction, the training cost in the 13th year began to be lesser than before the introduction, and in the 25th year, it decreased by 28.1% compared to before the introduction. Practical Implications: Firstly, NRP would be an effective way to solve the higher turnover and frequent departure of new nurses and the imbalance of nurses' composition. Secondly, although the costs of NRP are incurred in the early stages, in the end, NRP training costs are reduced compared to before the introduction of NRP. It is necessary to systematically understand the contribution effect of NRP by analyzing the economic value of NRP considering financial and non-monetary returns in the future and providing a basis for decision-making related to NRP implementation.