• Journal of the Korean association of regional geographers
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• v.11 no.5
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• pp.474-487
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• 2005

This paper aims to provide empirical evidence required to describe the level of achievement by analyzing students' item response in NAEP implemented in the United States in 2001. The geography assessment in the NAEP is aimed to test students of 4th, 8th, and 12th grades, and consists of content dimension and cognitive dimension, The former includes 'space and place' 'environment and society' and 'spatial dynamics and connections,' and the latter includes 'knowing' 'understanding' and 'applying,' The level of achievement is defined as three levels for each grade: Basic, Proficient, and Advanced. In this paper, descriptions of achievement is derived inductively from an analysis of student's responses to the items which were selected by using item-mapping method. As a result, there is a great difference between the level of achievement derived empirically from students' response and the level of achievement designed principally suggested by the expert committee. The former could have a contribution to the improvement in geography curriculum.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.87-95
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• 2006

In this paper, we propose a novel feature extraction method for face recognition, based on Discrete Cosine Transform (DCT), Energy Probability (EP), and Linear Discriminant Analysis (LDA). We define an energy probability as magnitude of effective information and it is used to create a frequency mask in OCT domain. The feature extraction method consists of three steps; i) the spatial domain of face images is transformed into the frequency domain called OCT domain; ii) energy property is applied on DCT domain that acquire from face image for the purpose of dimension reduction of data and optimization of valid information; iii) in order to obtain the most significant and invariant feature of face images, LDA is applied to the data extracted using frequency mask. In experiments, the recognition rate is 96.8% in ETRI database and 100% in ORL database. The proposed method has been shown improvements on the dimension reduction of feature space and the face recognition over the previously proposed methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.700-712
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• 2011

Due to recently advanced electrical devices, human can access computer network regardless of working location or time restriction. However, currently widely used mouse, joystick, and trackball input system are not easy to carry and they bound user hands exclusively within working space. Those make user inconvenient in Ubiquitous environments.. In this paper, we propose multiple dimension human motion detection system based on wireless sensor networks. It is a portable input device and provides easy installation process and unbinds user hands during input processing stages. Our implemented system is comprised of three components. One is input unit that senses user motions and transmits collected data to receiver. Second is receiver that conveys the received data to application, which runs on server computer. Third is application that performs command operations according to received data. Experiments shows that proposed system accurately detect the characteristics of user arm motions and fully support corresponding input requests.

• The korean journal of orthodontics
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• v.47 no.2
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• pp.100-107
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• 2017

Objective: To analyze the long-term changes in maxillary arch widths and buccal corridor ratios in orthodontic patients treated with and without premolar extractions. Methods: The study included 53 patients who were divided into the extraction (n = 28) and nonextraction (n = 25) groups. These patients had complete orthodontic records from the pretreatment (T1), posttreatment (T2), and postretention (T3) periods. Their mean retention and postretention times were 4 years 2 months and 17 years 8 months, respectively. Dental models and smiling photographs from all three periods were digitized to compare the changes in three dental arch width measurements and three buccal corridor ratios over time between the extraction and nonextraction groups. Data were analyzed using analysis of variance tests. Post-hoc multiple comparisons were made using Bonferroni correction. Results: Soft-tissue extension during smiling increased with age in both groups. The maximum dental width to smile width ratio (MDW/SW) also showed a favorable increase with treatment in both groups (p < 0.05), and remained virtually stable at T3 (p > 0.05). According to the MDW/SW ratio, the mean difference in the buccal corridor space of the two groups was $2.4{\pm}0.2%$ at T3. Additionally, no significant group ${\times}$ time interaction was found for any of the buccal corridor ratios studied. Conclusions: Premolar extractions did not negatively affect transverse maxillary arch widths and buccal corridor ratios. The long-term outcome of orthodontic treatment was comparable between the study groups.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3C
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• pp.419-425
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• 2004

This paper presents a new method which is calculated to use only three vanishing points in order to compute the dimensions of object and its pose from a single image of perspective projection taken by a camera. Our approach is to only compute three vanishing points without informations such as the focal length and rotation matrix from images in the case of perspective projection. We assume that the object can be modeled as a linear function of a dimension vector v. The input of reconstruction is a set of correspondences between features in the model and features in the image. To minimize each the dimensions of the parameterized models, this reconstruction of optimization can be solved by standard nonlinear optimization techniques with a multi-start method which generates multiple starting points for the optimizer by sampling the parameter space uniformly.

• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.4
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• pp.12-25
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• 1993

The purpose of this study is to interpret the landscape meaning of village grove and then combines this interpretations with landscape planing if it is possible. So we chose four village groves among seven villlage interpretations with landscape planing if it is possible. So we chose four village groves among seven village groves in HAMPYUNG & YOUNGKWANG Province(CHONRANAMDO, KOREA). The reason why we did it is that the meaning of korean groves is divided into three types(Confucianism, Feng-shui, Native belief etc.) according to original planting reasons. This study was done mainly by both referring to the regional character of those types and examining the nature of grove meanings. As a result of this process, we are able to find three demensions which were explained by physical-ecological, user's behavioral and cultural meaning. 1. Physical landscape of village grove is composed with ecological meaning that is related with people's land use not only inside but outside of it. So this kind of ecological meaning is the mutual relation among physical elements of village groves, for example old high trees, surface, user's facilities, land use around a grove and soon. 2. User's behavior meaning of grove shows that it has high relation with physical dimension, for example distance and accessiblity to a grove, linkage with open space around a village and so on. User's behavior inside of grove is usually divided into three types(recreation, play, ritual services). Especially, we were able to find a tendency to have numerous people use in the case of a village grove well to preserve its ritual service. 3. Cultural meaning of grove has the holistic character which usually defines the regional theme of each village and village grove(Confucianism, Feng-shui, Native belief etc.). So, the Landscape meaning of village grove is not only a physical shape but a certain concept existing inside of village grove. This diversed meaning existing in a grove have a direct effect on good fortune or misfortune of a village and its dwellers.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.163-166
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• 2005

Multilayer LTCC technology enables RF modules to be reduced dramatically by taking advantage of the three dimension flexibility. Compared to a conventional two dimensional PCB, LTCC allows higher density, reduced size, and lower cost. In this research, BPF based on LTCC for 900MHz ZigBee application was implemented which can replace SAW filter with using the material of the Dupont9599's dielectric constant 7.8. And distributed baud pass filter for 900MHz ZigBee system applications is presented. Using resonator stripline and capacitance, 2nd order band pass filter was designed. Adjusting resonator's length and capacitance is easy to tune at accurate center frequency by shifting band because ZigBee system is using narrow bandwidth, $902MHz^{\sim}928MHz$. Also resonator has no limitation in space, so reducing size is possibile. Designed filter had I.L. 2.8dB at 915MHz and attenuation at 815MHz, 1015MHz was 16dB, 15dB, respectively. Therefore, the sharpe cut-off and good insertion loss for ZigBee system application.

• Journal of the Mineralogical Society of Korea
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• v.10 no.2
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• pp.82-96
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• 1997

Buserties are known to have layer structures with variable C dimension which depended on the nature interlayer catious and contents of water molecular between edge-sharing [MnO6] octabedral layers. Na-, Ca-, Mg-, and Zn-buserties were synthesized in the laboratory and studied for to know the structural states of water molecules and the role of catious in the buserite structures. With lowering the relative humidity(RH), Ca-buserite begins to dehydrate at 27% RH and proceeds further very slowly. Mg- and Zn- buserite also slow dehydration above 2% RH. With gradual ineveasing temperature Ca- and Zn-buserite show abrupt shifting of 10$\AA$ peak (10$\AA$-phare) toward 7$\AA$ peak. All of 7$\AA$-phare are further dehydrated to 5$\AA$-phare by further increasing temperature. It suggests that interlayer catious play a crucial role in the dehydration behavious of buserites. Simulation of one-dimensional X-ray diffraction patterns of buserties show that buserites have three layers of water molecules of different types: the very loosely bound and tightly bend waters, instead of two layers that was regarded by previous authers. The very loosely bound water is sited I open space of the interlayer, the loosely bound water is bound on the tightly bound water by hydrogen bond, and the tightly bond water in coodinately bound on the interlayer catious.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.540-546
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• 1994

The authors treated three patients who chiefly complained functional anterior crossbite due to premature loss of primary molars by using removable space maintainer and functional appliances. In orthodontic practice, the mandibular rest position and the possibility of taking construction bite have been as the criteria for evaluation of functional factors involved in anterior crossbite. Functional anterior crossbites, if left untreated, may have deleterious effects on the development and function of craniofacial complex and TMJ. Objectives of the treatment were as follows: 1) to recover vertical dimension 2) to eliminate functional disharmony 3) to correct anterior reversed occlusion 4) to attain good facial esthetics 5) to prevent unfavorable growth of jaw & dentition Characterized craniofacial morphology resulting from the premature loss of deciduous molars could be recovered following the correction of crossbite. Therefore, it is recommended that in orthodontic diagnosis of functional anterior crossbite due to premature loss of deciduous molars, the craniofacial abnormality affected by that should be considered.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.31-36
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• 2011

In this paper, an analytical model of a cantilever beam having a midpoint load is considered for structural optimization and design. This involves creation of the geometry through a parametric study of all design variables. For this purpose, the optimization of the cantilever beam was elaborated in order to find the optimum geometry which minimizes its volume eventually for minimum weight by FEM (finite element method) analysis. Such geometry can be obtained by different combinations of width and height, so that the beam may have the same cross-sectional area, yet different dynamic behavior. So for optimum safe design, besides minimum volume it should have minimum vibration as well. In order to predict vibration, different dynamic analyses were performed simultaneously to identify the resonant frequencies and mode shapes belonging to the lowest three modes of vibration. Next, by introducing damping effects, the tip displacement and bending stress at the fixed end was evaluated under dynamic loads of varying frequency. Investigation of the results clearly shows that only structural analysis is not enough to predict the optimum values of dimension for safe design it must be aided by dynamic analysis as well.