• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.5
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• pp.192-200
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• 2014

Purpose: The objective of this study was to evaluate the interaction between 4-hexylresorcinol (4HR) and antibody as that affects the performance of a silk-4HR combination graft for soft tissue augmentation in an animal model. Methods: The silk graft materials consisted of four types: silk+10% tricalcium phosphate (TCP) (ST0), silk+10% TCP+1% 4HR (ST1), silk+10% TCP+3% 4HR (ST3), and silk+10% TCP+6% 4-HR (ST6). The antibody binding assay tested the 4HR effect and scanning electron microscopic (SEM) exam was done for silk grafts. The animal experiment used a subcutaneous pocket mouse model. The graft - SH0 or SH1 or SH3 or SH6 - was placed in a subcutaneous pocket. The animals were killed at one, two, and four weeks, postoperatively. The specimens were subjected to histological analysis and lysozyme assay. Results: Groups with 4HR applied showed lower antibody binding affinity to antigen compared to groups without 4HR. In the SEM examination, there was no significant difference among groups. Histological examinations revealed many foreign body giant cells in ST0 and ST1 group at four weeks postoperatively. Both ST3 and ST6 groups developed significantly lower levels of giant cell values compared to ST0 and ST1 groups (P < 0.001) at four weeks postoperatively. In the lysozyme assay, the ST1 and ST3 groups showed denser signals than the other groups. Conclusion: 4HR combined silk implants resulted in high levels of vascular and connective tissue regeneration.

• Clean Technology
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• v.6 no.1
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• pp.7-15
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• 2000

The purpose of this articls is to investigate the impacts of ISO 14001 certification on the compliance of environmental regulations by Korean companies. The impact of ISO 14001 certification on the industries obtained the certificates was studied through a survey with questionnaires, and the compliance of environmental regulations was investigated using governmental release data. Motivations of Korean companies' environmental management were mostly caused by customer's request and the requirement from foreign countries. Certified enterprises showed more 3 times compliance of environmental regulation than non-certified ones. Such results were accomplished by systematic environmental management such as clear implementation purpose and all employee's voluntary improving according to ISO 14001 requirement. The continuous monitoring system was possible through internal audit and biannual audit from the certification body, to be finally verified by the top management. The four steps in ISO 14001 environmental management system, which are objective, methodology, inspection and monitoring, has contributed to this achievement.

• Clean Technology
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• v.19 no.2
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• pp.121-127
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• 2013

The objective of this study is optimization of extrusion process for preparation of pellet-type adsorbents employed with alum sludge. Effects of water content and methyl cellulose as a binder on the possibility of extrusion and physical properties of pellet-type adsorbents were investigated. The physical characteristics of the pellet-type adsorbents were studied using nitrogen adsorption and compression strength. With a ratio of water to sludge, 63/100, the adsorbent was well extruded with a cylindrical form and the compressive strength was the highest. With increasing methyl cellulose content, the compressive strength of pellet-type adsorbent could be improved, but the specific surface area decreased. The breakthrough time of the hydrogen sulfide could be increased significantly through calcination and the breakthrough capacity reached to 1,700 mg/g, which seems to be due to increase of surface area during calcination.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.157-164
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• 2015

This paper describes subspace clustering of categorical data for convergence and integration. Because categorical data are not designed for dealing only with numerical data, The conventional evaluation measures are more likely to have the limitations due to the absence of ordering and high dimensional data and scarcity of frequency. Hence, conditional entropy measure is proposed to evaluate close approximation of cohesion among attributes within each cluster. We propose a new objective function that is used to reflect the optimistic clustering so that the within-cluster dispersion is minimized and the between-cluster separation is enhanced. We performed experiments on five real-world datasets, comparing the performance of our algorithms with four algorithms, using three evaluation metrics: accuracy, f-measure and adjusted Rand index. According to the experiments, the proposed algorithm outperforms the algorithms that were considered int the evaluation, regarding the considered metrics.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.33-44
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• 2020

The main objective of this study is to measure the concentration and deconcentration of the domestic freight forwarding system which illustrate the development trends in this industry. In this study, Herfindal-Hirschman index (HHI), shift-share analysis (SSA), and GINI coefficient combined with Lorenz curves were employed to investigate the domestic freight forwarders. The results are as follows: first, the HHI was used to assess the concentration of domestic freight forwarders in Vietnam. The downward trend from 0.117 in 2008 to 0.083 in 2018 indicate the deconcentration of domestic freight forwarders in Vietnam. Second, the SSA results indicated that the company Transimex showed the best performance with a shift effect of million VND 1,906,515 and a ABSGR value of million VND 2,158,232. Third, the GINI index go down from 0.468 to 0.393 in 2008-2018 as follow and the Lorenz curves covered a large part which make more demonstrate the deconcentration trend of freight forwarding in Vietnam. The results show that deconcentration is a trend in 2008-2018. The results of this study provides relevant data on freight forwarders which are not easily accessible to related stakeholders.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.25-33
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• 2004

To evaluate the seismic capacity of a multistorey building structures in performance based seismic design, it is needed to convert MDOF model into equivalent SDOF model. This paper presents predictions for interstory drift of multistorey structures using method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through performing nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. Comparing the interstory drift of multistorey structures calculated by time history analysis and those evaluated by an equivalent SDOF model, the adequacy and the validity of converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. Inelastic first mode shapes are expected to be more accurate than elastic first mode shapes in obtaining interstory drift of multistorey structures from equivalent SDOF model.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.6
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• pp.29-34
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• 1978

It has been investigated that the elect of an wideband FDM-FM signal upon an M-ary coherent PSK (MCPSK) signal in an intersystem radio interference environment between analog and digital systems, which had not been discussed before and had been obscure. It is assumed that PSK and FM signal are adjacently allocated in same radio frequency band. And the symbol error performance of MCPSK signal with co-channel and adjacent channel interference from an FDM-FM signal is evaluated with considering the receiver noise. The numerical results for the theoretical symbol error rates of MCPSK system in the presence of Gaussian noise and co-channel or adjacent channel interference are given in graphical forms as the function of carrier-to-noise ratio (CNR), carrier-to-interference ratio (CIR) and normalized carrier separation between the desired PSK and interfering FM signal. The objective of this research is to find some optimal conditions for coexistence of analog and digital systems in an intersystem interference environment. The results we obtained here stress a possible utilization of them for designing the frequency allocation, bandwidth and power of PSK channel in the intersystem interference from an FDM-FM signall.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.96-104
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• 2011

A halftoning method is used to obtain a binary image visually similar to a continuous gray-level image through the image output devices employing the limited number of gray-levels. As a halftoning method, the error diffusion method is widely used in various applications because of its low computational complexity and good image quality. However, this method weakens the edge in the process of error diffusion to the neighboring pixels. In this case, degradation of the edge quality and damage of the vivid image is expected. To solve these problems, the proposed method determines the adaptive error filter considering the error information of the present pixel and edge distribution of the neighbor pixels. Compared with the conventional methods for enhancing edges, the proposed method involves relatively a few process resources because of its simple procedure, still considerably improving the edges in the halftone image. To evaluate the objective image quality, the performance of the proposed method is compared with that of the conventional method in terms of the edge correlation and the local average accordance.

• The Journal of the Acoustical Society of Korea
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• v.21 no.6
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• pp.510-521
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• 2002

MBE (multi-band excitation) coder can achieve high qualify synthetic speech below 4.0 kbps. There are, however, significant differences of the fine structure between the original spectrum and the synthetic spectrum. They are mainly due to the exclusive partition of voiced and unvoiced regions in frequency domain and the decision procedure based on the experimental threshold. This paper proposes MMBE (mixed multi-band excitation) speech model to overcome drawbacks of a MBE coder. In addition, two analysis methods, which do not need my decision procedure based on a threshold, are presented. Both voiced and unvoiced components can be mixed over all the frequency axis in the MMBE speech model. To illustrate the potential of the proposed speech model, we develop a 2.6 kbps MMBE coder and compare it with a 2.9 kbps MBE coder by both objective and subjective methods. The results have shown that the proposed coder has a better performance even at a lower bit-rate compared with the MBE coder.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.23-32
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• 2010

Because ROTA(road traffic authority) analyzes the effects of accident reduction based on the data of 1-year after installation of RLC(red light camera), study of accident reduction effects over year after the installation of RLC is very short. This study deals with the traffic accident reduction during 3 years after the installation of RLC. The objective is to analyze the effects of accident reduction by year using EB method. In pursuing the above, the study uses the 951 accident data occurred at the 20 intersections which RLC are installed. The main results analyzed are as follows. First, the safety performance function (SPF) has been developed by the Poisson regression models which are statistically significant. Second, the results of an Empirical Bayes(EB) analyses showed that the accidents were reduced by the range from 2.73 to 38.75% after 1 year, from 6.85 to 47.36% after 2 year, and from 6.04 to 39.31% after 3 year from the installation of RLC.