• Tunnel and Underground Space
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• v.19 no.6
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• pp.498-506
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• 2009

The stability assessment of a concrete liner of a compressed air storage tunnel should be performed by an approach which is different from that commonly used for the liners of road tunnels, since the liner is exposed to high air pressure. In this study, the stability analysis method for the liner of compressed air storage tunnel is proposed based on the elastic and elasto-plastic solutions of the thick-walled cylinder problem. In case of elastic analysis, the yield initiation condition at the inner boundary is considered as the failure condition of the liner, while the condition which results in the extension of yielding zone to a certain depth is taken as a failure indicator of the liner in the elasto-plastic analysis taking Mohr-Coulomb criterion. The application of the proposed method revealed that the influence of the relative magnitude of boundary loads on the stability of liner is considerable. In particular, noting that the estimation of the outer boundary load may be relatively difficult, it is thought that the precise prediction of outer boundary load is very important in the analysis. Accordingly, the emphasis is put on the selection of the liner installation time, which may govern the magnitude of outer boundary load.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.2
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• pp.102-108
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• 2013

To understand the relationship of growth and water use efficiency (WUE) between superior and inferior families from open-pollinated progenies of P. densiflora, two families (one superior and one inferior families) in two open-pollinated progeny test sites were selected using volume growth at 26 years. And we compared environmental factors and WUE which was calculated from measured ${\delta}^{13}C$ in the wood. The ${\delta}^{13}C$ change during the last 20 years showed steady decrease and same pattern as WUE in the fertile site, while there was an inverse relationship between ${\delta}^{13}C$ and WUE in poor site, indicating an interaction between gene and environment. The superior family showed higher WUE than inferior family in poor site, indicating efficient stomatal control of the former under water stress. Water use efficiency calculated by carbon isotope composition can be used as a selection criterion for drought tolerance families in open-pollinated progenies of P. densiflora.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.122-129
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• 2020

Surion is required to install radios (U/VHF-AM, VHF-FM) capable of omni-directional communication. Therefore, this paper demonstrates the antenna performance test for the installation of the Surion communication antenna and the selection of optimal location. A simulation pattern analysis was performed employing the antenna, and a coupling test was performed by creating a new evaluation criterion. In addition, the results of the pattern flight test conducted at the previously suggested 1:20 turn and separation distance ratio were observed to be normal. However, the occurrence of voice cutoff was noted in the long-distance flight test. Therefore, in this paper, 1:300 (15 NM) is proposed as a new optimal ratio for predicting the long-distance flight test results in advance. Finally, the effectiveness of the proposed evaluation criteria was verified through long-distance flight tests. Consequently, it is expected to reduce the development schedule and cost by reducing the trial and error of the performance test for the Surion model. Also, the results of this study are expected to be used as standards for the installation of communication antenna and quality tests for other helicopters.

• Journal of KIISE:Software and Applications
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• v.31 no.3
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• pp.293-307
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• 2004

We consider the problem of scheduling tasks of a precedence constrained task graph, where each task has its execution time and deadline, onto a set of identical processors in a way that simultaneously minimizes the number of processors required and the total tardiness of tasks. Most existing approaches tend to focus on the minimization of the total tardiness of tasks. In another methods, solutions to this problem are usually computed by combining the two objectives into a simple criterion to be optimized. In this paper, the minimization is carried out using a multiobjective genetic algorithm (GA) that independently considers both criteria by using a vector-valued cost function. We present various GA components that are well suited to the problem of task scheduling, such as a non-trivial encoding strategy. a domination-based selection operator, and a heuristic crossover operator We also provide three local improvement heuristics that facilitate the fast convergence of GA's. The experimental results showed that when compared to five methods used previously, such as list-scheduling algorithms and a specific genetic algorithm, the Performance of our algorithm was comparable or better for 178 out of 180 randomly generated task graphs.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.45-49
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• 2001

As a series of studies to develop pest management system for sweet persimmon production matched with the quarantine criterion of sweet persimmon-imported county, a survey was conducted by questionnaire on pest management practice and scheme of increasing income in sweet persimmon farms in Korea. Above 80% of sweet persimmon farmers was over fifties in age. The greatest limiting factor for sweet persimmon production was thought to be disease by the farmers. Percentage of farmers who answered that the most important pest is anthracnose cause by Gloeosporium kaki, and stink bugs was 64.6% and 73.5%, respectively. In particular, the farmers did not consider Dichocrocis punctiferalis, a main targer insect for quarantine in USA, as serious problem. Obtaining information on pest management practice or decision-making on both selection of pesticide and time of pesticide application depended highly on their own experience with the highest proportion. Eight to nine times of pesticide applications a year was highest among farms with 56.6%. More than 80% of farmers recorded the diary of pesticide application. farmers considered increasing cost for pest management as the greatest problem with 35.4% in proportion, and 34.5% of farmers pointed out that increase in export is essential for increasing farm income with highest proportion.

• Journal of Distribution Science
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• v.11 no.2
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• pp.71-81
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• 2013

Purpose - The TOEIC test has been leading the change in the quality and the globalization of companies for about last 30 years. The TOEIC test is taken by about two million people each year and is used as a criterion to select new employees in companies or government offices, for performance ratings, and for overseas posting selections. Universities also use TOEIC test in various ways. Since the TOEIC test is used for the selection of new students for admission, transferring extra credits, scholarships, graduation certification, and admission of international students studying abroad, many universities all over the country provide students with TOEIC study lectures through their own language institutes. Despite the fact, there has been no research on the service quality or even the current situation of these institutes. Thus, this study aims to evaluate the factors that impact TOEIC lecture service quality and analyzes the effect of the expectation related to the education service quality and the result of education on intentional behavior. Research design, data, methodology - Data was collected by administering a survey to current TOEIC students from different university language institutes. The survey questionnaire comprised of a five-point Likert scale. The demographic analysis was conducted using the frequency analysis method and the factor analysis was conducted to verify the validity of questionnaire over any variable. The reliability analysis was conducted to verify the reliability of the results. Besides, multiple regression analysis, regression analysis, and mediated effect verification were also conducted. For education service quality, four different independent variables such as reliability, response, conviction, and sympathy were considered using the SERVQUAL survey model. Based on the research models, the study hypotheses below were formulated in order to recognize an effect relationship between the variables. The four hypotheses are, "the hypothesis on education service quality and TOEIC study result expectation," "the hypothesis on education service quality and behavioral intention," "the hypothesis on study result expectation and behavioral intention," and "the hypothesis on study result expectation and mediated effect." Results - The results are as follows. First, the factors like response, conviction, and sympathy have a positive influence on TOEIC study result expectations. Second, the TOEIC study result expectation has a positive influence on the factors of behavioral intention such as re-sign up, positive word-of-mouth, "loyalty towards school." Third, it was verified that the mediated effect on behavioral intention was influenced by education service quality at university foreign language institute, while the study result expectation has only a partial mediated effect. Conclusions - The implications of this study are summarized as follows: First, it suggests a new research model for the effect of the expectation related to the education service quality and the result of education in the university language institutes on the behavioral intention. Second, it has established a relationship between the education service quality and study result expectation by verifying the mediated effect on them.

• The Journal of Industrial Distribution & Business
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• v.9 no.9
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• pp.63-74
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• 2018

Purpose - The current study is to compare the cognition of stakeholders on hosting a mega sports event between Korea and the United States. In particular, to understand their cognition and perceptual conflict towards hosting a mega sports event, the study employed conflict theory. Furthermore, the study reviewed the role of social capital in the process of managing the mega sports events. Research Design, Data, and Methodology - Of homogeneous sampling, purposeful sampling method and criterion-based selection approach were used to collect interview data from key stakeholders who have been involved in hosting a mega sports events in Korea and the United States. In-depth interview transcripts were reviewed multiple tiems after transcription to extract concepts and meanings that were pertinenet to the experience involving hosting a mega sports event. Further member checks was conducted to increase the credibility of the results. Results - Results can be summarized as followed: First, stakeholders of Korea have a strong desire for positive economic effects of a mega sports event, compared to those in the United States who are more concerned in enhancing the public interests and concerns. Second, in Korea, various socio-political issues emerged at the same time and conflicts among multiple stakeholders have aggravated the situations to coordinate the issues. This was because legal system supporting socio-trust has not been established. On the other hand, major stakeholders of the United States consisted of community members who have socio-trust and networks. Thereby these social resources have been found playing a key role in building social capital that assists the stakeholders to coordinate the current issues and to solve them. Conclusions - The current study analyzed the cognition and perceptual conflict of stakehoders in a mega sports event. Social capital has beend found as a key catalyst to increase a network and cooperation among stakeholders. In order to enhance social capital in managing a mega sports event hosted in Korea, legal systems that establish networks and relationships among the related stakeholders need to be developed. Furthermore, the systematic guideline needs to be developed, organizing the sub-committees according to the types of stakeholders and the categorized common needs.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.1062-1075
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• 2010

In the medical image application the difference of intensity is widely used for the image segmentation and feature extraction, and a well known method is the threshold technique that determines a threshold value and generates a binary image based on the threshold. A frequently-used threshold technique is the Otsu algorithm that provides efficient processing and effective selection criterion for choosing the threshold value. However, we cannot get good segmentation results by applying the Otsu algorithm to chest X-ray images. It is because there are various organic structures around lung regions such as ribs and blood vessels, causing unclear distribution of intensity levels. To overcome the ambiguity, we propose in this paper an effective algorithm to extract pulmonary regions that utilizes the Otsu algorithm after removing the background of an X-ray image, constructs intensity-level maps, and uses them for segmenting the X-ray image. To verify the effectiveness of our method, we compared it with the existing 1-dimensional and 2-dimensional Otsu algorithms, and also the results by expert's naked eyes. The experimental result showed that our method achieved the more accurate extraction of pulmonary regions compared to the Otsu methods and showed the similar result as the naked eye's one.

• The Korean Journal of Applied Statistics
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• v.27 no.5
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• pp.681-691
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• 2014

Ranking-based conjoint analysis(RBCA) and choice-based conjoint analysis(CBCA) have attracted significant interest in various fields such as marketing research. When conducting research, the researcher has to select one suitable approach in consideration of strengths and weaknesses. This article performs an empirical comparison of the predictability of RBCA and CBCA in order to provide criterion for the selection. A new concept of measurement set is developed by combining the ranking set and choice set. The measurement set enables us to apply two approaches separately on the same consumer group that allows a fair comparison of predictability. RBCA and CBCA are conducted on consumer preferences for RTD-coffee; subsequently, the predicted values of market shares and hit rates are compared. The study result reveals that their predictabilities are not significantly different. Further, the result indicates that RBCA is recommended if the researcher wants to improve data quality by filtering out poor responses or to implement the market segmentation. In contrast, CBCA is recommended if the researcher wants to lessen the burden on the respondents or to measure preferences under similar conditions with the actual marketplace.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.37-42
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• 2008

Purpose: The objective of the study: At present, the spectacles, with its use as a medical aids or a fashion trimming, are recognized as one of the living necessities which can't be separated from human body. One of the features of spectacles is that it must be worn on any part of human body. Such a feature has to be satisfied under the condition an user keeps feeling comfortable with the rim of spectacles worn. In order to ensure meeting this condition, a criterion has to be arranged for the design of the rim of spectacles. In order to manufacture a rim of spectacles which allows an user to secure a comfortable range of vision as well as enhancing the feeling when to be worn, a manufacturing standard has to be established based on optical science. No precise rim of spectacles could be made from the manufacturing method depending on the manufacturer's sensibility. When the rim of spectacles was manufactured according to the incorrect standards, it may cause an user such a fatal result as myopia, hyperopia or astigmatism. Methods: This study focuses on providing a detailed explanation about the design of rim, which is the most important element during designing a rim of spectacles, making use of the optical elements of spectacles, and helping the manufacturers and the people who work in the spectacles-related business understand and recognize what is correct and exact and then leading them to establish a standard in respect to the manufacture and selection of spectacles. Results, Conclusions: Considering the fact there happen many errors in relation with the names of rim stipulated in the provisions of International Standards Organization (ISO), due to wrong interpretation by some of the rim manufacturers, the right interpretation should be given about the bridge which is directly connected to rim, so that the rims of spectacles manufactured in Korea could keep a favorable position in competing with the foreign products of same kinds.