• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.117-124
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• 2013

Association rule of data mining techniques is the method to quantify the relationship between a set of items in a huge database, andhas been applied in various fields like internet shopping mall, healthcare, insurance, and education. There are three primary interestingness measures for association rule, support and confidence and lift. Confidence is the most important measure of these measures, and we generate some association rules using confidence. But it is an asymmetric measure and has only positive value. So we can face with difficult problems in generation of association rules. In this paper we apply the similarity measures by probabilistic interestingness measure (PIM) with all marginal proportions (AMP) to solve this problem. The comparative studies with support, confidences, lift, chi-square statistics, and some similarity measures by PIM with AMPare shown by numerical example. As the result, we knew that the similarity measures by PIM with AMP could be seen the degree of association same as confidence. And we could confirm the direction of association because they had the sign of their values, and select the best similarity measure by PIM with AMP.

• Journal of Oral Medicine and Pain
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• v.43 no.2
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• pp.27-33
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• 2018

Purpose: Many researchers have established a connection between sleep disturbances and the symptoms of temporomandibular disorder (TMD) in adults, but there are a few studies targeted at adolescents with TMD. The aim of this study was to analyze the sleep pattern of adolescents with TMD and to determine the effect of poor sleep quality on their clinical symptoms. Methods: The subjects were composed of 47 adolescents with TMD. The sleep pattern and preliminary information of patients were measured by self-reported questionnaires; Pittsburgh Sleep Quality Index (PSQI) and Questionnaire for TMD analysis. TMD pain was scored using the Numerical Rating Scale. The Kruskal-Wallis test, Mann-Whitney U test, Fisher's exact test and logistic regression were used for statistical analysis. Results: The poor sleeping group had statistically more females (25.00% males, 75.00% females) than the good sleeping group. As compared with that of good sleepers, sleep quality of poor sleepers was significantly worse in the items of subjective sleep quality, sleep latency, sleep duration, sleep disturbances, daytime dysfunction and global PSQI score. The sleep time of adolescents was much longer during vacation ($7.20{\pm}1.38hours$) than during school days ($6.10{\pm}1.26hours$). Poor sleep of patients was associated with the pain in the ear or in front of the ear, in the face, jaw, throat or temple and in neck or back. Adolescents with pain in those areas had significantly higher proportion of poor sleepers than adolescents with no pain in those areas. Conclusions: The high ratio of girls in poor sleeping group could reflect the greater prevalence of TMD in women than in men. Pain in peri-temporomandibular joint areas, neck or back could negatively influence sleep quality of adolescents with TMD.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.385-391
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• 2014

We use a scale mainly for quantification when we study the psychological characteristics that we cannot observe. The utilization of a scale is frequent in scientific educational studies. The convenience offered by Likert scale, which is among the most frequently used, enable us to grasp characteristic attitude or recognition in students, and evaluate them against an affective domain. But a lot of errors occur, and has been noted as well in the case of utilizing Likert scale in the process. A central tendency in the utilization of Likert scale appears in this study, and the trend analyzes according to study objects and study contents, but we intend to find a way to utilize Likert scale. The results of study made on our countryside students show that the answers tend to get concentrated and a central tendency appears. Our countryside students were aware of the eyes surroundings them, have respect for elders through social experiences, and have had troubles with differentiated expression or personality in the group and cultural environments. According to the object of study, the central tendency appears more among older students than younger students, more among general students than gifted students. In the contents of study, the central tendency has been given more appearance in scope and their exposure has relatively been in large domain. Therefore when utilizing Likert scale in scientific education study, an error of central tendency appears as if they are results of the study. So, when applying the Likert scale to scientific study, we need to consider sociocultural environment, characteristics of an object and contexts of study. This enables avoiding dependence on numerical value of the utilization results, and interpret them correctly.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.233-238
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• 2003

Due to the impermeability of outer wall facilities such as Breakwaters which dissipates the wave energy and keeps harbor tranquility, the enclosed area of harbor becomes partially blocked and the water exchange can be reduced. Recent trends of port development protect water quality and emphasize Water-Front, so the method which enhances the circulation of harbor waters and the dilution of the water pollutants are studied. The best improvement of water quality is a remove of pollutant source on land, but an enclosed port must be enhanced the tidal exchange. For this end, the best improvement may be made a drain-route on the existing outer wall facilities. In this study, the numerical computations were carried out to predict the circulation of harbor waters and the tidal exchange through the drain-rout in the polluted harbor(Samchonpo-guhang) located at the east coast of South Sea. Computational models adopting FDM(Finite Difference Method) were used here and were already verified from the previous studies und ocean survey. As a result of this study, circulation and the tidal exchange at the harbor before and after introduction of drain-route were assessed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.133-133
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• 2008

Recently, as the down-scailing of field-effect transistor devices continues, Schottky-barrier field-effect transistors (SB-FETs) have attracted much attention as an alternative to conventional MOSFETs. SB-FETs have advantages over conventional devices, such as low parasitic source/drain resistance due to their metallic characteristics, low temperature processing for source/drain formation and physical scalability to the sub-10nm regime. The good scalability of SB-FETs is due to their metallic characteristics of source/drain, which leads to the low resistance and the atomically abrupt junctions at metal (silicide)-silicon interface. Nevertheless, some reports show that SB-FETs suffer from short channel effect (SCE) that would cause severe problems in the sub 20nm regime.[Ouyang et al. IEEE Trans. Electron Devices 53, 8, 1732 (2007)] Because source/drain barriers induce a depletion region, it is possible that the barriers are overlapped in short channel SB-FETs. In order to analyze the SCE of SB-FETs, we carried out systematic studies on the Schottky barrier overlapping in short channel SB-FETs using a SILVACO ATLAS numerical simulator. We have investigated the variation of surface channel band profiles depending on the doping, barrier height and the effective channel length using 2D simulation. Because the source/drain depletion regions start to be overlapped each other in the condition of the $L_{ch}$~80nm with $N_D{\sim}1\times10^{18}cm^{-3}$ and $\phi_{Bn}$ $\approx$ 0.6eV, the band profile varies as the decrease of effective channel length $L_{ch}$. With the $L_{ch}$~80nm as a starting point, the built-in potential of source/drain schottky contacts gradually decreases as the decrease of $L_{ch}$, then the conduction and valence band edges are consequently flattened at $L_{ch}$~5nm. These results may allow us to understand the performance related interdependent parameters in nanoscale SB-FETs such as channel length, the barrier height and channel doping.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.499-512
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• 2016

The boundary reaction method(BRM) is a substructure time domain method, it removes global iterations between frequency and time domain analyses commonly required in the hybrid approaches, so that it operates as a two-step uncoupled method. The BRM offers a two-step method as follows: (1) the calculation of boundary reaction forces in the frequency domain on an interface of linear and nonlinear regions, (2) solving the wave radiation problem subjected to the boundary reaction forces in the time domain. In the time domain analysis, the near-field soil is modeled to simulate the wave radiation problem. This paper evaluates the performance of the BRM according to modeling extent of near-field soil for the nonlinear SSI analysis of base-isolated NPP structure. For this purpose, parametric studies are performed using equivalent linear SSI problems. The accuracy of the BRM solution is evaluated by comparing the BRM solution with that of conventional SSI seismic technique. The numerical results show that the soil condition affects the modeling range of near-field soil for the BRM analysis as well as the size of the basemat. Finally, the BRM is applied for the nonlinear SSI analysis of a base-isolated NPP structure to demonstrate the accuracy and effectiveness of the method.

• Management & Information Systems Review
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• v.32 no.3
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• pp.107-125
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• 2013

This study deals with a strategic decision making in two level supply chain network design. This study presents more realistic mathematical model than the previous studies by considering simultaneous location of plants and distribution centers, determination of capacity level for both plants and distribution centers, and upper limit condition for numbers of locating plants and distribution centers. This paper tries to help the strategic decision making for two level supply chain network design. For this purpose, three different sized numerical examples are generated and optimal solutions are obtained by applying Excel Solver program. And sensitivity analysis is performed for the biggest sized example problem, which has 10 potential plants, 20 potential distribution centers, and 200 customer zones. After the plants being located are fixed, optimal minimum costs are obtained and compared for each of 7 different numbers of distribution centers to be located. As the number of distribution centers increases, changes in inbound transportation cost and outbound transportation cost can be derived. In case of considering cost as well as customer satisfaction level for two level supply chain network design, the analysis of this changes may help more sophisticated decision making.

• Spatial Information Research
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• v.9 no.2
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• pp.325-340
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• 2001

This research is to construct more useful Geo-spatial data by building spatial data to three dimensional and utilize the database effectively for development of application, maintenance and management program, and application technology, which is on going based on “Haeundae three dimensional database construction project”. Furthermore, the acquisition of geographic information data and the technological improvement of effective construction would be the important factors to judge the qualitative reputation of GIS. Above all, studies to create accurate data and overcome the error limitation are much more important than any other thing. Final form of Spatial Data to materialize efficient GIS(Geographic Information System) must be three dimensional spatial data which has attribute data, actual concept and numerical value of real world. In connection to that, development is on the move to improve building technique of useful spatial data and digitalize the entire country in cryberspace. $\ulcorner the cyber country lrcorner$is designed to mange the entire country systematically. This simulation would be able to cover administration of government institution, public service, corporate business and even the public life in the cyeberspace though the computer. Materialization of efficient GIS and establishment of condition as technically strong nation through the early realization of $\ulcorner the cyber country lrcorner$will provide a great opportunity to open up the global market with exportation of advanced technology.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.389-403
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• 2008

Seed morphological studies of 12 species of sect. Zygophyllidium and related Poinsettia using light and scanning electron microscopy were conducted to test the hypotheses of the sectional boundaries and species relationships. Characteristics of seeds, and the keys of identification of 12 species were presented. Seeds of 12 species were divided into 6 types based on the UPGMA tree from numerical analyses using nine seed characters. Type I, including E. uniglandulosa, is characterized by the foveolate seed with granulate testa cells. Type II, including species E. exstipulata, E. lagunensis, E. bilobata, E. hexagonoides and E. chersonesa, was recognized by the presence of inter-cellular granules among testa cells. Type III, including E. cyathophora, has a seed with acute apex, and concentric circles on the surface of testa cells. Type IV, including species of E. dentata and E. pentadactyla, has a seed with caruncle and lacking inter-cellular granules among testa cells. Type V, including E. hexagona, was characterized by the ovate seeds and lacking inter-cellular granules. Type VI, including E. eriantha and E. lacera, was recognized by the seeds with rectangular shape with caruncle. Based on the seed morphology, sect. Zygophyllidium should be defined only species with E. exstipulata, E. lagunensis, E. bilobata, E. hexagonoides and E. chersonesa. E. hexagona, traditionally included in this section, was closely related to E. dentata from Poinsettia.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.1
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• pp.91-101
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• 2008

Structural analysis models to develop live load distribution factors of simply supported prestressed concrete I-girder bridge should have the precision of the analysis results as well as modeling simplicity. This is due to the numerous frequency of structural analysis needed while developing live load distribution factors. In this study, an appropriate structural analysis model is selected by comparing previous researchs studies and models used in practical design. Also, the influence by the flexural stiffness of barrier and diaphragm on the live load distribution had been analyzed through comparing the numerical analysis and experimental tests. As a result, the model that the eccentric girder and the barrier and diaphragm are connected to the deck plate was appropriate in satisfying both accuracy and simplicity for structural analysis of simply supported prestressed concrete I-girder bridge. However, the barrier was analyzed to have insignificant influence on the live load distribution in spite of its variation of stiffness. The eccentric diaphragm showed little influence at 25% or higher of flexural stiffness. From the results, a model that the girder is rigidly connected to the deck plate in consideration of the eccentricity, the barrier is ignored and the whole section of diaphragm is supposed to be valid without eccentricity is decided as the most appropriate structural model to develop the live load distribution factors of simply supported prestressed concrete I-girder bridge in this study.