• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.905-914
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• 2017

We examine 554 state basic districts and 1832 householders in Busan metropolitan city to see whether the physical and walkable characteristics of housing influence apartment housing prices. We use two-level models modeling for a more accurate analysis. Walkable characteristics in level 2 state basic districts potentially explain 77% of the variation in housing values, with the highest impact on crime safety characteristics. Overall, our spatial multi-level analysis based on new state basic districts in Korea explained price variation better than previous studies, which considered each householder. The results provide policy opportunities for planners and citizen groups to pursue strategies that encourage the development of walkable and sustainable neighborhoods.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.146-155
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• 1994

In this paper, we desribe a new system, called BEST, that is used to develop a macromodel or behavioral model easily. It automatically calculates the component values of macromodel represented by equations to satisfy the given specification. Also, it gives the way to analyze both the behavioral model and transistor level circuit, and then compare the analysis results of them to check the correspondence under specific temperature and bias condition, and BEST optimizes the component values of macromodel. Other feature is to characterize MOSFET as switch model which consists of PWL-RC network. Finally, it is possible to generage multi-level netlist which consists of macro/switch/transistor level circuits, and user can determine the trade-off between simulation speed and accuracy. With the graphic user interface form of macromodel development system described above. BEST enable designers to make macromodel by themselves and to uas it. We applied BEST to develop the macromodel for the test circuit and got the 18.6 times simulation speed up with preserving the accuracy within 10% compared to the conventional transistor level circuit simulation. Also, applicability of optimization capability was verified.

• Journal of Distribution Science
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• v.11 no.3
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• pp.13-22
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• 2013

Purpose - Product purpose for optimal values solution for synthesize evaluative criteria and optimize product design values. In addition, product designer has to consider the product design to conform to project, laws and regulations, authentication, from the product design stage. Research design, data, methodology - How to use an evaluative criteria model's imprecise market data by evaluative criteria research design; product mapping relationships between design parameters and customer requirements using product predicted value method. An evaluative criteria model and their associated criteria status, product evaluative criteria model of results. Results - Therefore, after the enterprise product design project analysis, effectiveness and the customer degree of satisfaction must be appraised to obtain the maximum value for the benefit on behalf of the implementation goals, the promotion product level and market competition strength. Conclusions - In multi criterion decision making (MCDM), using its searching software capacity to obtain the optimal solution.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.279-293
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• 2023

This study investigates network effects to measure how strongly the early adopters affect the brand choice of the potential consumer. By using the Gumbel-Hougaard (GH) copula, this study checks the magnitude of network effects varied from country to country. To consider consumer heterogeneity and network effects in the growth market, this study proposes the multi-brand Gamma/Shifted-Gompertz (m-G/SG) model based on the GH copula. Out of eighteen Western European cellular phone market data and South Korea smartphone data sets, the m-G/SG model provides an improvement in the estimation accuracy over the Libai, Muller, and Peres model. The results show that network effects enhance (i) the polarization of brand choice probabilities as time elapses; (ii) the dominance of the more preferred and the earlier entered brand; and (iii) the deceleration of category-level diffusion. Potential followers can analyze their relationship with earlier entrants through the m-G/SG model and also establish an optimal market entry strategy.

• IE interfaces
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• v.14 no.3
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• pp.286-295
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• 2001

This paper addresses the problem of determining the proper level of concurrent spare parts(CSP) for a system consisting of multi-item parts under an available budget constraint. Initial provisioning of spare parts plays a major role in the acquisition of a new equipment system. Therefore, the proper level of spare parts should be on hand to maintain the availability of the system. This paper proposes a new CSP model and solution procedure that determines the proper level of spare parts satisfying the item priority and simultaneously available budget constraint.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.60-66
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• 2001

We designed a role-based access control model that can resolve the complicated tasks of control requirements. The designed access control model can control permissions efficiently use of a role-based access control. It guarantees the confidentiality integrity and availa information making use of identity-based and rule-based access controls. It can also centre information flow. Our access control model protects resources from unauthorized accesses b multi-level security policies such as role, security level, integrity level and ownership.

• Convergence Security Journal
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• v.1 no.1
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• pp.1-7
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• 2001

This paper design a role-based access control model that can resolves the complicated problems of access control requirements. In this paper, we designed an access control model which can control a permission making use up role-based access control, can guard the confidentiality, integrity and availability of information and can control illegal information flow. The designed access control model can protect resources from unauthorized accesses based on the role, multi-level security policies of security level, integrity level and ownership.

• Journal of the Korean Geographical Society
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• v.49 no.3
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• pp.405-422
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• 2014

Two important issues in hedonic model are to specify accurate model and delineate submarkets. While the former has experienced much improvement over recent decades, the latter has received relatively little attention. However, the accuracy of estimates from hedonic model will be necessarily reduced when the analysis does not adequately address market segmentation which can capture the spatial scale of price formation process in real estate. Placing emphasis on improvement of performance in hedonic model, this paper tried to segment real estate markets in Gangnam-gu and Jungrang-gu, which correspond to most heterogeneous and homogeneous ones respectively in 25 autonomous districts of Seoul. First, we calculated variable coefficients from mixed geographically weighted regression model (mixed GWR model) as input for clustering, since the coefficient from hedonic model can be interpreted as shadow price of attributes constituting real estate. After that, we developed a spatially constrained data-driven methodology to preserve spatial contiguity by utilizing the SKATER algorithm based on a minimum spanning tree. Finally, the performance of this method was verified by applying a multi-level model. We concluded that submarket does not exist in Jungrang-gu and five submarkets centered on arterial roads would be reasonable in Gangnam-gu. Urban infrastructure such as arterial roads has not been considered an important factor for delineating submarkets until now, but it was found empirically that they play a key role in market segmentation.

• Journal of the Korea Society of Computer and Information
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• v.29 no.10
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• pp.35-45
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• 2024

In this paper, we propose Multi-Scale Feature Knowledge Distillation for 3D Object Detection (M3KD), which extracting knowledge from the teacher model, and transfer to the student model consider with multi-scale feature map. To achieve this, we minimize L2 loss between feature maps at each pyramid level of the student model with the correspond teacher model so student model can mimic the teacher model backbone information which improves the overall accuracy of the student model. We apply the class logits knowledge distillation used in the image classification task, by allowing student model mimic the classification logits of the teacher model, to guide the student model to improve the detection accuracy. In KITTI (Karlsruhe Institute of Technology and Toyota Technological Institute) dataset, our M3KD (Multi-Scale Feature Knowledge Distillation for 3D Object Detection) student model achieves 30% inference speed improvement compared to the teacher model. Additionally, our method achieved an average improvement of 1.08% in 3D mean Average Precision (mAP) across all classes and difficulty levels compared to the baseline student model. Furthermore, when integrated with the latest knowledge distillation methods such as PKD and SemCKD, our approach achieved an additional 0.42% and 0.52% improvement in 3D mAP, respectively, further enhancing performance.

• Ocean Systems Engineering
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• v.10 no.4
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• pp.359-371
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• 2020

The performance of a multi-level overtopping wave energy converter (OWEC) has been numerically and experimentally investigated in a two-dimensional wave tank in order to study the effects of opening width of additional reservoirs. The device is a fixed OWEC consisting of an inclined ramp together with several reservoirs at different levels. A particle-based numerical simulation utilizing the Lattice Boltzmann Method (LBM) is used to simulate the flow behavior around the OWEC. Additionally, an experimental model is also built and tested in a small wave flume in order to validate the numerical results. A comparison in energy captured performance between single-level and multi-level devices has been proposed using the hydraulic efficiency. The enhancement of power capture performance is accomplished by increasing an overtopping flow rate captured by the extra reservoirs. However, a noticeably large opening of the extra reservoirs can result in a reduction in the power efficiency. The overtopping flow behavior into the reservoirs is also presented and discussed. Moreover, the results of hydrodynamic performance are compared with a similar study, of which a similar tendency is achieved. Nevertheless, the LBM simulations consume less computational time in both pre-processing and calculating phases.