• Journal of Korea Water Resources Association
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• 제49권8호
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• pp.645-656
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• 2016

The study performed a regional flood frequency analysis and proposed a regression equation to estimate design floods corresponding to return periods for ungauged basins in Geum-river basin. Five preliminary tests were employed to investigate hydrological independence and homogeneity of streamflow data, i.e. the lag-one autocorrelation test, time homogeneity test, Grubbs-Beck outlier test, discordancy measure test ($D_i$), and regional homogeneity measure (H). The test results showed that streamflow data were time-independent, discordant and homogeneous within the basin. Using five probability distributions (generalized extreme value (GEV), three-parameter log-normal (LN-III), Pearson type 3 (P-III), generalized logistic (GLO), generalized Pareto (GPA)), comparative regional flood frequency analyses were carried out for the region. Based on the L-moment ratio diagram, average weighted distance (AWD) and goodness-of-fit statistics ($Z^{DIST}$), the GLO distribution was selected as the best fit model for Geum-river basin. Using the GLO, a regression equation was developed for estimating regional design floods, and validated by comparing the estimated and observed streamflows at the Ganggyeong station.

• Journal of Digital Convergence
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• 제14권4호
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• pp.69-78
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• 2016

The purpose of this study is to analyze convergent effects of team interaction and team metacognition of participants on a continuous participation in the university learning community. We developed 19 items of team interaction and 17 items of team metacognition through literature review. The subjects were 113 students who participated in learning community in A university. The results are as follows. First, team interaction level and team metacognition level can affect a continuous participation in learning community. The higher team interaction is and the lower team metacognition is, the higher continuous participation is. Second, among team interaction factors that affect a continuous participation in learning community, the more number of learning is and the more encouragement of one another is, the higher continuous participation is. But the less participation of members is, the less flow to learning is, and the less learning time is, the lower a continuous participation is. Third, among team metacognition factors that affect a continuous participation in learning community, the more number of learning is, the higher continuous participation is. But the more use of various learning tools is and the more learning time is, the lower continuous participation is. Based on these results, the convergent ways of support for continuous participation in the university learning community are as follows. First, supporting system is needed to induce students to experience the positive atmosphere of learning community by increasing number of learning to facilitate team interaction and urging them to encourage one another. Second, providing the effective utilization method is necessary for students to fully acknowledge the necessity and value of team metacognition activity.

• Management & Information Systems Review
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• 제31권4호
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• pp.33-56
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• 2012

The purposes of this paper are analysed the relationship between environmental regulation and financial performance in Korea. The financial performance of listed companies and Outside Auditing firms was evaluated by logistic regression. First, R&D investment is proportionally correlated with the ability to comply with environmental regulations. It can be explained increase of investment in R&D causes enhancement of compliance of environmental regulations with development of environmental technology. Second, statistical significance is not observed between financial aspects such as current ratio, debt-to-equity ratio, cash flow, and operating profit margin and the ability to comply with environmental regulations. It indicates high financial performance could not directly lead investment for the ability of that. Third, in terms of structural aspects, firm size and employees have a reliable correlation with compliance with environmental regulations due to high attention of larger firms for PR, and IR, while capital intensity and gravity, and exports do not. Finally, violation of environmental regulations is not affect by the controlling shareholder ownership.

• Journal of Korea Port Economic Association
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• 제27권4호
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• pp.187-205
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• 2011

In considering the size of container logistic flow of Korea, one-port as a hub port is desirable in Busan Port, but as development of Busan Port and Gwangyang Port began as two-ports, they are good as mega hub ports. In case when ports of other regions such as Incheon Port are additionally developed, it is very likely that they become feeder ports rather than mega hub ports. As capital area uses Incheon Port and Pyeongtaek Port for transportation, fierce competition arises due to excessive facilities of terminal companies and it is not easy to be profitable. Therefore, it is more profitable to develop regional hub ports centering on near-sea routes of Korea China Japan rather than local ports such as Incheon Port and Pyeongtaek Port for intensive trade and transportation in the capital area. To mitigate excessive competition between container terminal companies, we need administrative guidance to maintain adequacy through comparing tariffs between ports of Japan and China which are in competitive relations with Korean ports. This study analysed efficiency of container terminal companies in Gwangyang Port, Busan Port and Incheon Port using data for five years from 2006 to 2010. As analytical variables, length of quay, floor area of yard, the number of cranes and employees were analytical variables and a total freight volume was a productive factor.

• Journal of the Korean Society of School Health
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• 제20권1호
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• pp.91-101
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• 2007

Purpose: The present study intended to reveal the association between the physique of adolescent women and dysmenorrhea, and the factors related to the frequency of dysmenorrhea. Methods: The study subjects included 511 girls of a women's high school in Daejeon city and they were, during the period of March 1st through April 30th, 2005, given self-administered questionnaires about frequency of menstruation, age, physique, exercise, and such menstruation-related items as age of menarche, menstrual period and days, and amount. Results: As with the frequency of dysmenorrhea, 38.4% experienced it 「always」, 44.6% 「occasionally」, and 17.0% 「almost scarcely」, and those with dysmenorrhea accounted for 83.0% of the subjects. The frequency of dysmenorrhea was not significant difference according to the BMI and HPI. However, the lower the age of menarche and the greater the amount of menstrual flow, the more frequent dysmenorrhea. The symptoms of dysmenorrhea included the highest frequency of low back pain(68.5%) and it was followed by abdominal pain(65.9%), sensibility(54.0%), fatigue(51.7%), and nervousness(49.5%). These accompanied symptoms tended to be worse as the frequency of dysmenorrhea increased. The multiple logistic regression analysis revealed that the relative risk of frequency of dysmenorrhea is 2.2 times in age of 14, by a standard age of 15 as menarchial age, 2.2 in 13, and 3.1 in below 12. The menstrual days was 3.0 times in both below 2 days and over 8 days with the standard days of 3-7 days. The menstrual amount was 1.9 times in the group with a greater amount of menstrual bleeding and 1.5 times in the group with a less amount than the normal group, respectively. Conclusion: The above results suggest that the rate of experiencing dysmenorrhea was up to 83.0% and 38.4% from these had dysmenorrhea upon every menstruation. It is thought that dysmenorrhea could be a great disadvantage sufficient to impair optimal health to a larger body of school girls. Further, for quality of life, it is required that more fundamental strategies instead of pain killers or others for palliation of dysmenorrhea would be established among adolescents.

• Journal of Korea Water Resources Association
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• 제51권2호
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• pp.141-150
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• 2018

The purpose of this study is to evaluate the future hydrologic behavior affected by the potential climate and land use changes in upstream of Anseong-cheon watershed ($366.5km^2$) using SWAT. The HadGEM3-RA RCP 4.5 and 8.5 scenarios were used for 2030s (2020-2039) and 2050s (2040-2059) periods as the future climate change scenario. It was shown that maximum changes of precipitation ranged from -5.7% in 2030s to +18.5% in 2050s for RCP 4.5 scenarios and the temperature increased up to $1.8^{\circ}C$ and $2.6^{\circ}C$ in 2030s RCP 4.5 and 2050s 8.5 scenarios respectively based on baseline (1976-2005) period. The future land uses were predicted using the CLUE-s model by establishing logistic regression equation. The 2050 urban area were predicted to increase of 58.6% (29.0 to $46.0km^2$). The SWAT was calibrated and verified using 14 years (2002-2015) of daily streamflow with 0.86 and 0.76 Nash-Sutcliffe model efficiency (NSE) for stream flow (Q) and low flow 1/Q respectively focusing on 2 drought years (2014-2015) calibration. For future climate change only, the stream discharge showed maximum decrease of 24.2% in 2030s RCP 4.5 and turned to maximum increase of 10.9% in 2050s RCP 4.5 scenario compared with the baseline period stream discharge of 601.0 mm by the precipitation variation and gradual temperature increase. While considering both future climate and land use change, the stream discharge showed maximum decrease of 14.9% in 2030s RCP 4.5 and maximum increase of 19.5% in 2050s RCP 4.5 scenario by the urban growth and the related land use changes. The results supported that the future land use factor might be considered especially for having high potential urban growth within a watershed in the future climate change assessment.

• Journal of Intelligence and Information Systems
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• 제23권2호
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• pp.1-17
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• 2017

The deep learning framework is software designed to help develop deep learning models. Some of its important functions include "automatic differentiation" and "utilization of GPU". The list of popular deep learning framework includes Caffe (BVLC) and Theano (University of Montreal). And recently, Microsoft's deep learning framework, Microsoft Cognitive Toolkit, was released as open-source license, following Google's Tensorflow a year earlier. The early deep learning frameworks have been developed mainly for research at universities. Beginning with the inception of Tensorflow, however, it seems that companies such as Microsoft and Facebook have started to join the competition of framework development. Given the trend, Google and other companies are expected to continue investing in the deep learning framework to bring forward the initiative in the artificial intelligence business. From this point of view, we think it is a good time to compare some of deep learning frameworks. So we compare three deep learning frameworks which can be used as a Python library. Those are Google's Tensorflow, Microsoft's CNTK, and Theano which is sort of a predecessor of the preceding two. The most common and important function of deep learning frameworks is the ability to perform automatic differentiation. Basically all the mathematical expressions of deep learning models can be represented as computational graphs, which consist of nodes and edges. Partial derivatives on each edge of a computational graph can then be obtained. With the partial derivatives, we can let software compute differentiation of any node with respect to any variable by utilizing chain rule of Calculus. First of all, the convenience of coding is in the order of CNTK, Tensorflow, and Theano. The criterion is simply based on the lengths of the codes and the learning curve and the ease of coding are not the main concern. According to the criteria, Theano was the most difficult to implement with, and CNTK and Tensorflow were somewhat easier. With Tensorflow, we need to define weight variables and biases explicitly. The reason that CNTK and Tensorflow are easier to implement with is that those frameworks provide us with more abstraction than Theano. We, however, need to mention that low-level coding is not always bad. It gives us flexibility of coding. With the low-level coding such as in Theano, we can implement and test any new deep learning models or any new search methods that we can think of. The assessment of the execution speed of each framework is that there is not meaningful difference. According to the experiment, execution speeds of Theano and Tensorflow are very similar, although the experiment was limited to a CNN model. In the case of CNTK, the experimental environment was not maintained as the same. The code written in CNTK has to be run in PC environment without GPU where codes execute as much as 50 times slower than with GPU. But we concluded that the difference of execution speed was within the range of variation caused by the different hardware setup. In this study, we compared three types of deep learning framework: Theano, Tensorflow, and CNTK. According to Wikipedia, there are 12 available deep learning frameworks. And 15 different attributes differentiate each framework. Some of the important attributes would include interface language (Python, C ++, Java, etc.) and the availability of libraries on various deep learning models such as CNN, RNN, DBN, and etc. And if a user implements a large scale deep learning model, it will also be important to support multiple GPU or multiple servers. Also, if you are learning the deep learning model, it would also be important if there are enough examples and references.

• Journal of Intelligence and Information Systems
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• 제16권4호
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• pp.131-145
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• 2010

The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

• Nuclear Medicine and Molecular Imaging
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• 제42권3호
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• pp.192-200
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• 2008

To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.