• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.520-526
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• 2007

The accuracy of model surgery is one of important factors which can influence the outcome of orthognathic surgery. To evaluate the accuracy of digitalized model surgery, we tried the model surgery on a software after transferring the mounted model block into a digital model, and compared the results with that of classical manual model surgery. We could get the following results, which can be used as good baseline analysis for the clinical application. 1. We made the 3D scanning of dental model blocks, and mounted on a software. And we performed the model surgery according to the previously arranged surgical plans, and let the rapid prototyping machine produce the surgical wafer. All through these process, we could confirm that the digital model surgery is feasible without difficulties. 2. The digital model surgery group (Group 2) showed a mean error of $0.0{\sim}0.1mm$ for moving the maxillary model block to the target position. And Group 1, which was done by manual model surgery, presented a mean error of $0.1{\sim}1.2mm$, which is definitely greater than those of Group 2. 3. Remounted maxillary model block with the wafers produced by digital model surgery from Group 2 showed the less mean error (0.2 to 0.4 mm) than that produced by manual model surgery in Group 1 (0.3 to 1.4 mm). From these results, we could confirm that the digital model surgery in Group 2 presented less error than manual model surgery of Group 1. And the model surgery by digital manipulation is expected to have less influence from the individual variation or degree of expertness. So the increased accuracy and enhanced manipulability will serve the digital model surgery as the good candidate for the improvement and replacement of the classical model surgery, if careful preparation works for the clinical adjustment is accompanied.

• Korean Journal of Social Welfare
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• v.56 no.2
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• pp.215-235
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• 2004

A little understood but rapidly growing phenomenon in our society is remarriage. By 2002, 21% of marriage involved the remarriage of one or both partners. Furthermore, the ratio of remarriage of women has outnumbered the ratio of remarriage of men, which is remarkable change compared to the traditional culture putting a taboo on women's remarriage in Korea. The purpose of this study is to construct the perspective and the direction of programs for enhancing the remarriage family functioning. For the purpose, we explore the intrinsic vulnerability to family dissolution of remarriage and ill preparation for remarriage of people. There are unrealistic myths around, lack of informations on, absence of guideline for remarriage family life. Also, we discuss the process of remarriage family development, which leads us to the conclusion that the remarriage shows totally different family structure and family interaction from first marriage nuclear family. Based on discussion mentioned above, several suggestions are provided for developing programs for remarriage family functioning. Above all, the family developmental perspective on remarriage is more useful paradigm rather than deficit-comparison perspective for remarriage family. Also, the programs for remarriage family functioning should challenge the unrealistic myths around remarriage such as the instant love between step-parents and step-children, the re-created nuclear family, etc. Also, several points such as the remarried family developmental stage, the disparity in expectation of man and woman on remarriage, and the tendency to scapegoat a stepmother should be considered in programs for enhancing remarriage family functioning.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.449-455
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• 2011

This study was performed to develop antimicrobial films using polyvinyl alcohol and methyl cellulose. Methyl cellulose and polyvinyl alcohol films plasticized with PEG(polyethylene glycol) were prepared by solvent casting process under addition of 0.025~1.0 wt% ampicillin and 0.1~1.0 wt% streptomycin as an antimicrobial agent. The mechanical properties of prepared films were examined by universal testing machine(UTM). Tensile strength of methyl cellulose films was 15.44~21.70 $N/mm^2$. Tensile strength of PVA(15 wt%) film was 20.2~51.5 $N/mm^2$, and the tensile strength of the antimicrobial films were decreased linearly with increasing the antibiotic loading amount up to 1 wt%. Antimicrobial activities of PVA and methyl cellulose films containing ampicillin and streptomycin through the disc diffusion test for the Staphylococcus aureus and Escherichia coli. The antimicrobial activity of methyl cellulose films and PVA containing ampicillin were higher than that of containing streptomycin methyl cellulose films. The results indicate the films may be a proper materials for antimicrobial packing applications.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.138-148
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• 2006

In constructing projects, there exist various kinds of work interferences, which cause a delay of the outset and completion of planned schedule because of some attributions, such as variability, uncertainty and complexity, and so schedule delay has been treated as a natural phenomenon. To reduce or prevent the schedule delay, a constant confirmation of schedule delay and a preparation of counter plans for finding out the cause structure of schedule delay should have been done. However, all this time the research has been mostly done on the calculation method or claim cases of schedule delay, and the range of analysis method of the cause structure of schedule delay has been multifarious from industrial views to views of specific work. Moreover, the classifying system and analysis method did not consider the trait, which cause the schedule delay, in constructing projects. For this reason, it is difficult to compare the cause of delay factors of the projects and to understand the effect of schedule delay by each factor. This paper restricts the range of the cause analysis of schedule delay to the field of site management in the projects and divides the cause structure of schedule delay into the cause objects and cause attributes of schedule delay according to the input elements. The system of classifying causes of schedule delay is examined by interviews with experts and questionnaire. Additionally, this paper analyzes the attributes of cause attributes and cause subjects and presents the analysis method and procedure of schedule delay with the application of VSM.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.35-44
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• 2016

Various risk factors are known to be the nature of construction project execution process. These factors lead to potential claims, dispute mediation, arbitration, and litigation which can result in huge loss of money and time. Therefore, it is necessary for construction companies in Korea to improve overall project management capability through the evaluation before entering into the overseas construction market. Also, after examination of the claim and dispute caused by construction project risks, a substantial degree of influence and active preparation for the claim and dispute management should be confirmed via the effect analysis of the each factors. Main claim causes were derived through claim and dispute cases involved with domestic construction projects. As a prediction result of the main claim, 16.1% of the construction change claim, 5.7% of the bad faith claim and 2.7% for the construction delay claim were found to be the portion of the total construction cost. As a result of this analysis, risk management methodology was suggested to improve a project management capability for domestic construction companies through analysis result of the main factors of construction claims.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.880-885
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• 2008

Spray pyrolysis was applied to prepare spherical silica particles with mesopores of a regular structure. The physical properties such as surface area, pore size, pore structure, particle size, and morphology were studied by BET, SEM, SAXS, and DLS analysis. At a fixed gas flow rate, the BET surface area changed from 200 to $1,290m^2/g$ as changing the CTAB/TEOS molar ratio from 0.05 to 0.3. At a fixed CTAB/TEOS ratio, the surface area of silica particles was varied from 1,062 to $1,305m^2/g$ with changing the gas flow rate from 10 to 40 l/min. The average pore size measured by BJH desorption was about $21{\sim}23{\AA}$ and not significantly influenced by the CTAB/TEOS ratio and the gas flow rate. Finally, the highest surface area which was $1,305m^2/g$ were obtained when the CTAB/TEOS ratio and the gas flow rate were 0.2 and 20 l/min, respectively. According to SAXS analysis, the prepared silica particles showed a strong peak at $2{\theta}=2.6^{\circ}$ and two minor peaks around $2{\theta}=4.4^{\circ}$ and $5.1^{\circ}$, which are due to regular mesopores of hexagonal structure. The morphology of silica particles prepared were spherical shape and the average particle size was $1.0{\mu}m$.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.282-288
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• 2015

A new energetic thermoplastic elastomer based on the azidated polybutadiene(Az-PBD)/ethylene vinyl acetate copolymer (EVA) blends was prepared, and structure and properties of the blends were invetigated by SEM, DSC, DMA, tensile testing and combustion test. The Az-PBD was synthesized via a two-step process involving the addition reaction of commercially available 1,2-PBD with $Br_2$ and subsequent nucleophilic substitution reaction of the brominated PBD with $NaN_3$. EVA/Az-PBD with 90/10, 80/20, 70/30 (wt/wt) was prepared by a solution blending. SEM, DSC, and DMA results revealed that the blends are partially compatible and Az-PBD is dispersed in continuous EVA matrix. Tensile test showed that modulus and tension set increased while elongation-at-break of the blends decreased with increasing Az-PBD content in the blends, but all the blends showed a elongation at break as high as 700% and a tension set of less than 5%, indicating that the blends are typically elastomeric. Combustion test showed that, with increasing Az-PBD content in the blend, higher energy can be released.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.6
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• pp.481-491
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• 2005

Purpose: The aim of the present study is to evaluate the effect of autogenous bone and allograft material coverd with a bioresorbable membrane on bone regeneration after a simultaneous installation of implant. Materials and methods: Twelve healthy rabbits, weighing about $3{\sim}4$ kg, were used in this experiment. Following impalnt(with 3.25 mm diameter and 8 mm length) site preparation by surgical protocol of $Oraltronics^{(R)}$, artificial bony defect, 5mm sized in height and depth, was created on femoral condyle using trephine drill(with 5 mm diameter and 5 mm length). Then implant was inserted. In the experimental group A, the bony defect was filled with autogenous particulated bone and coverd with $Lyoplant^{(R)}$ resorbable membrane. In the experimental group B, the bony defect was filled with allograft material(Orthoblast $II^{(R)}$) containing demineralized bone matrix and covered with $Lyoplant^{(R)}$. In the control group, without any graft materials, the bony defect was covered with $Lyoplant^{(R)}$. The experimental group A and B were divided into each 9 cases and control group into 3 cases. The experimental animals were sacrificed at 3, 6 and 8 weeks after surgery and block specimens were obtained. With histologic and histomorphometric analysis, we observed the histologic changes of the cells and bone formation after H-E staining and then, measured BIC and bone density with KAPPA Image $Base^{(R)}$ system. Results: As a result of this experiment, bone formation and active remodeling process were examined in all experimental groups and the control. But, the ability of bone formation of the experimental group A was somewhat better than any other groups. Especially bone to-implant contact fraction ranged from 12.7% to 43.45% in the autogenous bone group and from 9.02% to 29.83% in DBM group, at 3 and 8 weeks. But, bone density ranged from 15.67% to 23.17% in the autogenous bone group and from 25.95% to 46.06% in DBM group at 3 and 6 weeks, respectively. Although the bone density of DBM group was better than that of autogenous bone group at 3 and 6weeks, the latter was better than the former at 8 weeks, 54.3% and 45.1%, respectively. Therefore these results showed that DBM enhanced the density of newly formed bone at least initially.

• Korean journal of communication and information
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• v.22
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• pp.107-130
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• 2003

This study evaluated the debate formats adopted in the 2002 Televised Presidential Debates. Presidential Debate Committee have sponsored Televised Presidential Debates during the official campaign period. However, it is not easy task for the Committee to coordinate each party's different interests, such as voters, candidates, and broadcasters. Presidential candidates tries to use the debates as one of their campaign strategies. Broadcasters argued limitations in programming and production process. Regardless of the obstacles, voters expect that the committee makes ideal debate formats. The committee adopted two new forms in the 2002 Debates. The committee allowed direct exchange between candidates as well as advance question preparation by candidate. The committee intends that candidates focus on discussing policy issues. Some studies found that the debate format to allow direct exchange between candidates makes candidates focus on image issues rather than policy issues. The findings of this study are similar to the previous studies'. The new debate formats adopted in 2002 televised presidential debates did not guarantee policy issue oriented discussion. The committee or scholars should evaluate the debate formats used in the presidential debates in order to establish ideal debate formats that gives important information for votes to determine their choice. It is necessary to systematically evaluate the debate formats of former presidential campaign for developing right debate formats.

• Clean Technology
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• v.24 no.1
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• pp.27-34
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• 2018

Catalytic filter has many advantages for the industrial application owing to its bi-functional ability to treat nitrogen oxides and particulate simultaneously. The technical feasibility of using the catalytic filter in the flue gas treatment process will be more promoted if the high porous ceramic sheet filter is utilized. However, it is not easy to prepare the effective catalytic filter using sheet filter as it has less room for catalyst support due to its thin layer. In this study, catalytic filter using a domestic ceramic sheet filter element has been prepared and conducted the experimental evaluation for NO reduction performance. The current sheet filter element shows the low catalytic activity less than 92% conversion for NO concentration 700 ppm at the face velocity $0.02m\;s^{-1}$. This unexpected low catalytic activity seems to be caused by the present of extraordinary large pores from the lack of uniformity in the pore size distribution of the sheet filter. The large pore size of the sheet filter is reduced by composing the smaller powder as its raw material, which presents improvement in NO conversion more than 96%. More improvement is observed showing 98% NO conversion which is applicable to a commercial plant when the catalyst coating layer is expanded by adding the large $TiO_2$ particles during the catalyst preparation. Both of above two methods is regarded as that the broad gates of the larger pores in the coating layer are effectively filled with the proper catalyst. So these results encourage the utilization of sheet filter as a good catalytic filter material with its potential merit of high permeability.