• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.881-888
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• 2017

In general, the choking phenomenon occurs by flow acceleration for a turbine at high pressure ratio condition. In choking condition, total pressure ratio increases without mass flow rate variation. It is hard to predict choking characteristics by using conventional meanline analysis which used mass flow inlet boundary condition. In the present study, the algorithm for predicting choking point is developed to solve the problem. Moreover, performance estimation algorithm after choking is presented by reflecting the flow behaviour of flow expansion at choked nozzle or rotor. The analysis results are compared with 3D CFD analysis and experimental data to validate present method.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.49-54
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• 2006

The purpose of this study was to determine the effect of expansion joint spacing (slab size) on the life cycle costs of owning Portland Cement Concrete (PCC) airfield pavements. Previous research has shown that slab size has a statistically significant impact on pavement performance. A probabilistic life cycle cost analysis was performed to determine if the effect of slab size on pavement performance would affect the total cost of ownership of PCC pavements. Data from 48 Pavement Condition Index (PCI) inspections of military and civilian airfields were used to develop probability-of-distress-by-condition curves, which were then used to develop probabilistic cost-of-repair-by-condition curves. A present worth life cycle cost analysis was then performed for various slab sizes, using construction costs, rehabilitation costs, and maintenance costs. Maintenance costs were determined by assuming a condition deterioration rate appropriate for each slab size and applying the cost-by-condition curves. The probabilistic cost-of-repair-by-condition curves indicated that smaller slabs are more expensive to repair on a unit cost basis. Life cycle cost analysis showed that larger slabs have a higher total cost of ownership than smaller slabs due to a faster rate of deterioration.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.2
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• pp.71-79
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• 2008

The Certification system will be able to expect that effect of marketing and the corporate image rising, if the certification body guarantees the contents of certification against industrial technical advance and safety, environment and efficiency, quality when it is suitable in the standard which is provided. The certification system where the private organization operates but recently on the legal notarization outside is disordering and the trust regarding the certification falls and the objective and gist of origin are damaged. But recently the trust of certification has fallen and the objective and gist of origin are damaged. Because the non-government certifications are disordering. Also the damage of the consumers majority occurs but it is insufficient the investigation analysis against the present condition regarding a non-government certification system and the operation actual condition. So it is necessary the actual condition where the countermeasure against hereupon is urgent. In this study, we present the operation direction of efficient against non-government certification system through investigation and the analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1278-1281
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• 2004

Several workers reported the relationship between osteoporosis and age-related reductions in the BV/TV (bone volume fraction) of vertebral trabecular bones. However, there were few micro finite element (micro-FE) models to account for the treatments of the osteoporotic trabecular bone. In the present study, micro-FE models of osteoporotic and hormone-treated bone models were constructed to analyze the effect of specimen location and boundary condition on mechanical characteristics of hormone treatment model for osteoporotic trabecular bone. Top and bottom sections of specimens were also investigated individually to study the effect of specimen location. Hormone-treated models were allowed to have the same relative BV/TV (13.4％) as that used in models of previous researchers. The present study reported the elastic and plastic characteristics of the osteoporosis and hormone-treated bone models. In the present study, in-situ boundary condition was applied to the simulated compression tests for in-vivo condition of vertebral trabecular bone. The present study indicated that the hormone therapy was likely to improve the mechanical characteristics of osteoporotic bones and the mechanical characteristics of vertebral trabecular bone specimen were dependent on the captured location and boundary condition.

• Journal of the Korean Home Economics Association
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• v.41 no.10 s.188
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• pp.1-13
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• 2003

The purpose of this study is to make clear the present condition and the reason of noise in one-room ape multi-family housing around the campus by residents' subjective responses. The respondents are 104 residents living in one-room ape multi-family housing around the campus. The results are as follows. 1) The residents show relatively non-positive responses at evening and night on the present condition of noise in outdoor and indoor of building or indoor of house unit. 2) The types of outdoor noise of building are checked frequently are 'talking loudness' and 'traffic noise'. 'Walking and talking sounds in stairs and corridors' among the types of indoor noise of building shows highest percentage. They answer 'living equipment noise' and 'water hammer' as major types of indoor noise of house unit.

• KIEAE Journal
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• v.14 no.4
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• pp.97-102
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• 2014

This study has an intention of investigating residential present condition of small households, and analysing the factors which have an influence on the choice of residence as a first step of the efficient plan of group residential facility providing a variety of residential present condition. The study defines the meaning of small households on the basis of statistical data that were presented at the National Statistical Office in order to analyse the factors influencing the choice of residence and investigate residential present condition. And the analysis range target is from 20 to 30 aged groups such as university students, social rookie year, and married couples without children. According to the result of analysing residential actual conditions of small households, The choice of residence has various factors. But the study supposes that it reflects three elements of workplace, University and housing price in the choice of residence. So the study investigated the related data.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.805-810
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• 2000

The purpose of this study is to predict long-term structural safety on the Yonggwang Unit 3 prestressed concrete containment building. The aging-related degradations of its main structural materials are investigated and the effects of the property variation of time-dependent materials on the structural behavior of containment building are also assessed through the analysis on the ultimate pressure capacity. The nonlinear finite element analyses for both the design criteria condition a the present aging condition are conducted to assess the present structural capacity of the containment building As a result, it is verified that the structural capacity of the Yonggwang Unit 3 containment building under the present aging condition is judged to be still rugged. n addition, the sensitivity of the ultimate pressrue capacity of containment building according to th degradation levels of the structural materials are assessed. Finally, it is showed that the sensitivity levels are in the order of the tendon, rebar and concrete in case of individual material degradations, and the tendon-rebar, tendon-concrete and rebar-concrete in case of coupled material degradations.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.3-12
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• 2010

This study mainly focused on the intergenerational exchange as a plan to revitalize the social participation of the elderly. The purpose of the study is to propose a plan for revitalizing future intergenerational exchange through the present condition analysis in the aspects of activity, space and consciousness for the elderly-centered intergenerational exchange. The study scope is the local welfare level, broad sense of exchange for the aged, children, youths and local residents, and the study objects are the personnel in charge of welfare policy and the staff in charge of operating general social welfare centers and the users of the facilities users. A survey questionnaire type research was sent through post mail to 278 social welfare centers, and 384 government offices within the jurisdictions. Among them, the responses were collected from 22 general social welfare centers and 26 offices within the jurisdictions. A proposal of a plan to revitalize intergenerational exchange that needs to be implemented in future based on the consideration of the present condition and characteristics of the intergenerational exchange of general social welfare center.

• Korean Journal of Environment and Ecology
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• v.20 no.2
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• pp.170-187
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• 2006

The purpose of this study is to provide a basic datd for establishing a basic park management plan for Bulamsan Urban Nature Park. This research surveys very closely about the present condition of the natural ecosystem based on the examination and analysis of the present condition. This research suggests development and management methods for environment-friendly park by understanding damages on the ecosystem due to overuse, as well as park facilities and their effects on the surrounding environment, using quantative analysis. The three steps: researching the present condition research, ecosystem evaluation, and park management plan were taken in order. The present condition research is based on the general condition, natural environment, and natural ecosystem data. In the ecosystem evaluation, wildlife habitats evaluation, landscape evaluation, and biotope type research which is a materialized form of the plant ecosystem were excuted based on the present condition research data. In the park management plan step, 1) classified ecosystem and landscae preservation zone, ecosystem protection zone and ecosystem restoration zone as ecosystem and landscape preservation plan, 2) plannings for ecosystem, fine landscape preservation, damaged area restoration and recovery plan were established in order to suggest environment-friendly plan,

• Advances in materials Research
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• v.12 no.1
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• pp.43-65
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• 2023

Free vibration analysis of power law and sigmoidal sandwich plates made up of functionally graded materials (FGMs) has been carried out using finite element based higher-order zigzag theory. The present model satisfies all-important conditions such as transverse shear stress-free conditions at the plate's top and bottom surface along with continuity condition for transverse stresses at the interface. A Nine-noded C0 finite element having eleven degrees of freedom per node is used during the study. The present model is free from the requirement of any penalty function or post-processing technique and hence is computationally efficient. The present model's effectiveness is demonstrated by comparing the present results with available results in the literature. Several new results have been proposed in the present work, which will serve as a benchmark for future works. It has been observed that the material variation law, power-law exponent, skew angle, and boundary condition of the plate widely determines the free vibration behavior of sandwich functionally graded (FG) plate.