• The Journal of Korean Academy of Prosthodontics
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• v.38 no.2
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• pp.255-263
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• 2000

The purpose of this study was to compare the microleakage of the composite resin cores according to surface treatment, dentin bonding agents, and thermocycling. For this study, 120 extracted premolar teeth were used. Flat occlusal surfaces were prepared with diamond disk, and treated with air-abrasion, acid-etching, combination. The composite resin core was built with Z-100 after application of Scotchbond Multi-Purpose and All-Bond 2. Prepared specimens were thermocycled for 2,000 cycles. Specimens were immersed in 1% methylene blue solution for 24hours at $37^{\circ}C$. The microleakage was measured with a inverted metallurgical microscope(BHS313, Olympus, Japan). The following conclusions were drawn from this study: 1. The microleakages in the groups treated with air-abrasion and with acid etching were greater than that of the groups treated with combination method before thermocycling(p<0.05), the microleakages of the groups treated with air-abrasion were greater than that of the groups treated with acid-etching and combination method after thermocycling(p<0.05) 2. There were no significant difference between groups using Scotchbond Multi-Purpose and the groups using All-Bond 2. 3. Thermocycling didn't affect the change of microleakage in all cases.

• Journal of Korean Society for Quality Management
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• v.45 no.2
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• pp.191-207
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• 2017

Purpose: To develop an interactive version of the conventional process capability-based approach, called 'Interactive Process Capability-Based Approach (IPCA)' in multi-response surface optimization to obtain a satisfactory compromise which incorporates a decision maker(DM)'s preference information precisely. Methods: The proposed IPCA consists of 4 steps. Step 1 is to obtain the estimated process capability indices and initialize the parameters. Step 2 is to maximize the overall process capability index. Step 3 is to evaluate the optimization results. If all the responses are satisfactory, the procedure stops with the most preferred compromise solution. Otherwise, it moves to Step 4. Step 4 is to adjust the preference parameters. The adjustment can be made in two modes: relaxation and tightening. The relaxation is to make the importance of one of the satisfactory responses lower, which is implemented by decreasing its weight. The tightening is to make the importance of one of the unsatisfactory responses higher, which is implemented by increasing its weight. Then, the procedure goes back to Step 2. If there is no response to be adjusted, it stops with the unsatisfactory compromise solution. Results: The proposed IPCA was illustrated through a multi-response surface problem, colloidal gas aphrons problem. The illustration shows that it can generate a satisfactory compromise through an interactive procedure which enables the DM to provide his or her preference information conveniently. Conclusion: The proposed IPCA has two major advantages. One is to obtain a satisfactory compromise which is faithful to the DM preference structure. The other is to make the DM's participation in the interactive procedure easier by using the process capability index in judging satisfaction/unsatisfaction. The process capability index is very familiar with quality practitioners as well as indicates the process performance levels numerically.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.500-509
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• 2013

This study reports a numerical analysis of the internal flow characteristics of the integrated urea-SCR muffler system with the various geometries of the multi-perforated tube which is set up between the muffler inlet and in front of SCR catalysts. The multi-perforated tube is generally used to disperse uniformly the urea-water solution spray and to make better use of the SCR catalyst, resulting in the increased $NO_x$ reduction and decreased ammonia slip. The effects of the multi-perforated tube orifice area ratios on the velocity distributions in front of the SCR catalyst, which is ultimately quantified as the uniformity index, were investigated for the optimal muffler system design. The steady flow model was applied by using a general-purpose commercial software package. The air at the room temperature was used as a working fluid, instead of the exhaust gas and urea-water solution spray mixture. From the analysis results, it was clarified that the multi-perforated tube geometry sensitively affected to the formation of the bulk swirling motion inside the plenum chamber set in front of the SCR catalyst and to the uniformity index of the velocity distribution produced at the inlet of the catalyst.

• Journal of the Korean housing association
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• v.26 no.6
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• pp.1-8
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• 2015

This study aims to develop a solution to inter-floor noise complaints by exploring cases of noise complaints between floors and by identifying the demands and needs of the residents. For this purpose, a survey was conducted targeting residents who were sorted into groups depending on their experiences with inter-floor noise. This survey was carried out from June 11, 2014 to June 16, 2014. A total of 100 copies of the questionnaire was distributed to the residents, of which 98 were completed and collected. Data were statistically processed in accordance with SPSS WIN 18.0. The results showed that the leading causes of inter-floor noise complaints were residents' differences in schedules and their inconsideration in behavior. Thus, the solution to this issue is three-fold: first, to take social measures in order to improve communication and understanding between residents so they can be mindful of their noise levels; second, to reinforce noise control regulation; and third, to improve noise reduction design within the building architecture.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.2
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• pp.72-82
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• 2002

This paper presents the design technology of a Graphic Generator which drives the embedded aircraft display equipments such as HUD(Head-Up Display) and MFD (Multi-Function Display) those provide pilot with the most important mission information. The main issue of this design is how we can implement the real-time embedded graphic generator using a general purpose processor as a substitute for the obsolete the production of specific graphic processor in the military market. So we proposed two kinds of method that one is a software solution so called graphic kernel system, interpreting the display file, controlling the graphic system and pre-processing graphic primitives, the other is a hardware solution so called graphic engine, interpreting passed commands through the graphic kernel system, post-processing the looping calculation taking much of time as implemented by software. We have tested and verified the functionalities and the required performance of Graphic Generator.

• Computers and Concrete
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• v.28 no.5
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• pp.465-478
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• 2021

On the premise of ensuring that the static performance of the concrete spreader is met, the first-order natural frequency of the concrete spreader is increased, and the weight of the main beam is reduced. ANSYS is used as an analysis tool to perform modal analysis on the concrete spreader. The natural frequency, mode shape and modal test verification will be obtained to ensure the accuracy of finite element model analysis. Using the ANSYS designxplorer module, the size of the main beam is set, and the response surface model between the parameter variables and the optimization objective is established according to the experimental design points. Screening algorithm and MOGA algorithm are used to multi-optimize the stress, first-order natural frequency and girder weight, and the optimal solution is obtained by comparison. The results of modal analysis are consistent with those of the experiment, and a set of optimal solutions is obtained through the optimization algorithm. The optimal solution obtained can meet the purpose of increasing the first-order natural frequency of the concrete spreader and reducing the weight of the main beam under the premise of ensuring the overall dynamic and static performance of the concrete spreader.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.161-170
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• 2007

The purpose of this study is to find the solution that overcomes the existing assumption of symmetric cost functions in multi-class assignment. In the assignment problem, the assumption of a symmetric cost function means that the link cost is determined by each unique mode and is not affected by any other modes. In this study, the authors have applied a diagonalized algorithm and a heuristic model based on column generation to a multi-class assignment model and analyzed the result. Through the study, the authors found that the diagonalized algorithm produces equilibrium solutions by the initial convergence condition. In contrast to the diagonalized algorithm, the column generation algorithm has improved the solution model to overcome the problem of equilibrium solutions in the diagonalized algorithm.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.135-139
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• 2008

Through the industrialization since 1960, Korean housing has been developed in a uniform way which is to demolish first and then construct from the scratch. In this process, detached houses and multi-family living detached houses have disappeared without being paid much attention. The detached houses with blood or non-blood related multi-family living situations are typically popular, and worthy enough to explore for professionals right and creative solutions to enhance their values. But many of the people suffered for the expenses and the absence of the idea to enhance their housing themselves. The purpose of this research is to clarify user's demands of developing an adaptable lifespan house and to try to find the solution about the expenses of self improvement. This study used a Small group workshop Panel Method. The workshop consisted of three stage, such as the awareness of their existing residence and lease status, the needs of the housing improvements and the demands of the adaptable house. This study is expected to serve as a fundamental data to promote discussion on reuse of existing residence building and to promote rental detached houses.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.4
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• pp.324-333
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• 2013

The purpose of this paper is to improve the efficiency of multi-objective topology optimization using a genetic algorithm (GA) with bar-system representation. We proposed a new GA using an elite initial population obtained from a Solid Isotropic Material with Penalization (SIMP) using a weighted sum method. SIMP with a weighted sum method is one of the most established methods using sensitivity analysis. Although the implementation of the SIMP method is straightforward and computationally effective, it may be difficult to find a complete Pareto-optimal set in a multi-objective optimization problem. In this study, to build a more convergent and diverse global Pareto-optimal set and reduce the GA computational cost, some individuals, with similar topology to the local optimum solution obtained from the SIMP using the weighted sum method, were introduced for the initial population of the GA. The proposed method was applied to a structural topology optimization example and the results of the proposed method were compared with those of the traditional method using standard random initialization for the initial population of the GA.

• Architectural research
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• v.20 no.4
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• pp.103-108
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• 2018

Wandering behavior is a serious problem among the elderly in nursing homes, yet it has received relatively little study As multi-family houses built before the '80s in South Korea were designed, it did not take account into issues related to parking so that at present parking became a big issue. The Seoul Metropolitan Government tried various ways to sort out the parking problem in multi-family house areas, but inadequate parking and illegal parking are still an ongoing problem. Thus, the purpose of this study was to examine current situation on resident parking only and illegal parking centered on a congested area of multi-family houses in Seoul and present the improvement plan of parking problems through case investigation home and abroad. As the result of the survey, it has been identified that the subject area consists of 506 households in total and 186 parking spaces and also, 100 cars in parking space or parking lot in housing space and 143 in illegal parking. Green parking business and open access parking system were suggested as solution plan for parking problem. Thus, it is expected that through green parking business for 6 houses and the parking lot of elementary schools around, the illegal parking problem would be sorted out.