• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1158-1164
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• 2007

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of civil infrastructure is rapidly growing unprecedentedly in civil engineering practice. Accordingly, it is expected that the life-cycle cost in the 21st century will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, so far, most researches in Koreahave only focused on roadway bridges, which are not applicable to railway bridges. Thus, this paper presents the formulation models and methods for uncertainty-based LCCA for railroad bridges consideringboth objective statistical data available in the agency database of railroad bridges management and subjective data obtained form interviews with experts of the railway agency, which are used to anew uncertainty-based expected maintenance/repair costs including lifetime indirect costs. For reliable assessment of the life-cycle maintenance/repair costs, statistical analysis considering maintenance history data and survey data including the subjective judgments of railway experts on maintenance/management of railroad bridges, are performed to categorize critical maintenance items and associated expected costs and uncertainty-based deterioration models are developed. Finally, the formulation for simulation-based LCC analysis of railway bridges with uncertainty-based deterioration models are applied to the design-decision problem, which is to select an optimal bridge type having minimum Life-Cycle cost among various railway bridges types such as steel plate girder bridge, and prestressed concrete girder bridge in the basic design phase.

• Korean Journal of Human Ecology
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• v.13 no.1
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• pp.123-133
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• 2004

To investigate the factors that contribute to consumer satisfaction with the purchase of clothing, questionnaires were distributed and then consumer groups were classified according to their fashion life style on the internet shopping. The results were as follows: 1. Consumers groups were classified into trendy, Indifferent, brand inclined, conservative, and practicality- minded group by the fashion life style of the internet users. 2. From the analysis of the satisfaction factors on the internet clothing shopping, the factors were product variety, shopping convenience, customer service, confidence in order filling. 3. The most important consumer satisfaction factors according to the fashion life style were as follows: the trendy group considered the variety of clothing design most important. As for the Indifferent group, the tn, diversified collection of the products, and the convenience of unlimited time and space access that the internet site provided, were highly appreciated. With regard to the brand-inclined group, the presentation of product information and the convenience of unlimited time and space factors were highly appreciated. For the conservative group, the time and space factor were highly regarded, As far as the practicality-minded group was concerned, product price and size, the convenience of unlimited time and space access, and punctual delivery schedule were focused.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.73-80
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• 2006

High speed machining(HSM) technique is widely used in the appliance, automobile part and mold industries, because it has many advantages such as good quality, low cost and rapid machining time. But it also has problems such as tool breakage, smooth tool path, and so on. In particular, small size end mill is easy to break, so it must be changed before interrupting operation. Generally, the tool life of small size end mill is affected by the milling conditions whose selected parameters are spindle speed, feedrate, and width of cut. The experiments were carried out by full factorial design of experiments using an orthogonal array. This paper shows optimal combination and mathematical model for tool life, Therefore, the analysis of variance(ANOVA) is employed to analyze the main effects and the interactions of these milling parameters and the second-order polynomial regression model with three independent variables is estimated to predict tool life by multiple regression analysis.

• Korean Institute of Interior Design Journal
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• v.15 no.6 s.59
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• pp.172-177
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• 2006

Most of the Korean multi-dwelling houses have less than 20 years of lifespan. Because the environmental issues such as energy consumption, limited resources, and demolition waste problems became been more and more critical, we now need to focus on long lasting and adaptable buildings. Korean wall bearing apartment buildings are constructed with site cast concrete for core, exterior, and interior together with pipes varied, so when the buildings are old and life style of the users changes, it is difficult to maintain and renovate these buildings. In this study, to resolve the problems described above, two types of Korean long life multi-dwelling housing models which represent improved durability and adaptability responding user's needs and life style changes were proposed with various methods as follows: Either column and beam structure or flat slab structure was used to utilize space better. To make maintenance easier and renovation economical for both public space and each unit, plumbing pipes, ducts, and conduits were clustered at the cores and public corridors with access doors and light weight partitions with steel studs and raised floors or above-ceiling spaces were used in lieu of site cast concrete walls and floor slabs with varied pipes.

• Archives of design research
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• v.17 no.3
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• pp.403-412
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• 2004

Ubiquitous computing will bring on comprehensive changes of environment. We need to understand how this change will change human life and what will be needed in this circumstances. Then we have to develope the appropriate sonics in ubiquitous computing environment. The design of ubiquitous computing environment has the concept of designing human life. Thus to develope the scenarios which are able to predict human life is to make a foundation of developing design concepts effectively. However there is a gap due to the lack of the dear methodology between the analyzing trend of technology and the process of estimating the future life and developing the service scenarios. So, most of the scenarios which have developed up to now do not present the service that exactly reflects all the complicated and pluralistic sides of environment. The service in the ubiquitous computing environment should take the form of grasping the user's context and offering the information with the most adequate way. Therefore we have to know when they need services, where they use services and what kind of services they want. It means that we should understand the life and the environment of user clearly and wholly with the prospect of developing service. We also need the method for developing UC(ubiquitous computing) service based on this. This study focuses on the future family life and analyzes the user's context from a point of view of service development and in this ground, we have progressed the research about the methodology to develop the UC service scenario for suggesting the service. Through the applying of this methodology, we could analyze the user's context systematically and could make the best use of the analyzed data for proposal service idea. And the UC service scenarios which reflect future life on the basis of various use's context could be developed.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.4
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• pp.87-96
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• 2021

Determining design rainfall is the first step to plan an agricultural drainage facility. The objective of this study is to evaluate whether the current method for parameter estimation is reasonable for computing the design rainfall. The current Gumbel-Kendall (G-K) method was compared with two other methods which are Gumbel-Chow (G-C) method and Probability weighted moment (PWM). Hourly rainfall data were acquired from the 60 ASOS (Automated Synoptic Observing System) stations across the nation. For the goodness-of-fit test, this study used chi-squared (𝛘²) and Kolmogorov-Smirnov (K-S) test. When using G-K method, 𝛘² statistics of 18 stations exceeded the critical value (𝑥²_a=0.05,df=4=9.4877) and 10, 3 stations for G-C method, PWM method respectively. For K-S test, none of the stations exceeded the critical value (D^a=0.05_n=0.19838). However, G-K method showed the worst performances in both tests compared to other methods. Subsequently, this study computed design rainfall of 48-hour duration in 60 ASOS stations. G-K method showed 5.6 and 6.4% higher average design rainfall and 15.2 and 24.6% higher variance compared to G-C and PWM methods. In short, G-K showed the worst performance in goodness-of-fit tests and showed higher design rainfall with the least robustness. Likewise, considering the basic assumptions of the design rainfall estimation, G-K is not an appropriate method for the practical use. This study can be referenced and helpful when revising the agricultural drainage standards.

• Korean Institute of Interior Design Journal
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• v.22 no.4
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• pp.62-69
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• 2013

The purpose of this study is to research the viewpoint of space practice method through the discussion about social space. The study researched how social practice strategy is unfolded through the understanding about daily life, space manufacture and interaction. As a social practice, space design should adopt the interaction approach method on the basis of social relationship latent in the base of space. As a result of study, the viewpoint of space practice can be summarized into 3 viewpoints as below. First, it is the viewpoint of recognition through the experience meeting daily life. Rural space is the one of experience where daily life and social relationship interact each other. As a delicate sensible experience, it is the recognition of special space detected in the space where daily life occurs. Second, it is the viewpoint of form creation as a media product of society and space. Space is a whole creature of the relationship that has been formed socially as a historical process. Depending on the goal of community, new form is created by sharing the characteristic of space and having sense of kinship. Third, it is the viewpoint of tuning as a practice for subject participation. Rural space is the daily space to practice structured society subjectively through interaction. In the place of subjective life, there should a space practice with the tuning and cooperation method between subject and society. The main vein of space practice, which is analyzed with the discussion about social space, shows that out lives are maintained by space practice and directly connected to social relationship and structure. After all, the space, which is searched for through space design, has a clear subjectivity, ensures abundant subject life and is led to realization of community value.

• Journal of the Korea Furniture Society
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• v.23 no.4
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• pp.364-371
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• 2012

I designed a dietary life kitchen utensils which is focused by the shape of split bamboo that has meaning of health and safety and the shaman who is the religion and incantation performer, and who solve problems, which are impossible to solve in common methods, by borrowing the power and granting the meaning which is connected with transcendent existence and principal. Having closest relation with human being's diet culture is being changed with adding beauty instead of the part of simple practical aspect in our normal life. I tried to show incantation effect with keeping the characteristic of kitchen utensils by granting the symbolic meaning of shamanism which is the shelter that is projected the desire of human beings. the materials were produced of an ebony and steel and varnished with lacquer for coloring. For hand shape, which is hard to treat in irregular forms, the religious image of shamanism was formed by casting which expresses the touch of an ebony and the cold characteristic of metal. an overall design doesn't detail excessively distort or largely transform the form of dietary utensils, keeps its individuality, and emphasizes the image by figuring a grip part which a human can see and a body can approach. in addition, I try to show a point that shamanism has affected human life for long time and symbolic meaning of bamboo-shape shows health and safety. And these things vest with each dietary life tools and should be the role of enzyme about the effect of human life.

• Journal of Power System Engineering
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• v.21 no.1
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• pp.43-49
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• 2017

This work aims to investigate on the low cycle fatigue life assessment, which is adopted on the strain-life relationship, or better known as the Coffin-Manson relationship, and also the strain energy density-based model. The low cycle fatigue test results of Alloy 617 weldments under $900^{\circ}C$ have been statistically estimated through the Coffin-Manson relationship according to the provided strain profile. In addition, the strain energy density-based model is proposed to represent the energy dissipated per cycle as fatigue damage parameter. Based on the results, Alloy 617 weldments followed the Coffin-Manson relationship and strain energy density-based model well, and they were compatible with the experimental data. The predicted lives based on these two proposed models were examined with the experimental data to select a proper life prediction parameter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1358-1368
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• 2006

This paper proposes a Pareto artificial life algorithm for solving multi-objective optimization problems. The artificial life algorithm for optimization problem with a single objective function is improved to handle Pareto optimization problem through incorporating the new method to estimate the fitness value for a solution and the Pareto list to memorize and to improve the Pareto optimal set. The proposed algorithm was applied to the optimum design of a journal bearing which has two objective functions. The Pareto front and the optimal solution set for the application were presented to give the possible solutions to a decision maker or a designer. Furthermore, the relation between linearly combined single-objective optimization problem and Pareto optimization problem has been studied.