• Transactions of Materials Processing
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• v.3 no.3
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• pp.302-319
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• 1994

A new approach to die shape optimal design in bimetal extrusion of rods is presented. In this approach, the design problem is formulated as a constrained optimization problem incorporated with the finite element model, and optimization of the die shape is conducted on the basis of the design sensitivities. The combinations of the core and sleeve materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1760-1767
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• 2004

Sequential sampling approaches of a metamodel that sampling points are updated sequentially become a significant consideration in metamodeling technique. Sequential sampling design is more effective than classical space filling design of all-at-once sampling because sequential sampling design is to add new sampling points by means of distance between sampling points or precdiction error obtained from metamodel. However, though the extremum points can strongly reflect the behaviors of responses, the existing sequential sampling designs are inefficient to approximate extremum points of original model. In this research, new sequential sampling approach using the sensitivity of Kriging model is proposed, so that new approach reflects the behaviors of response sequentially. Various sequential sampling designs are reviewed and the performances of the proposed approach are compared with those of existing sequential sampling approaches by using mean squared error. The accuracy of the proposed approach is investigated against optimization results of test problems so that superiority of the sensitivity approach is verified.

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.1
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• pp.17-27
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• 2020

Purpose: The purpose of this study is to identify the difference in toilet approach way by wheelchair users according to the direction of the door and to suggest the layout of the toilet rooms most accessible to the wheelchair users. Methods: Survey to wheelchair users about approach to toilet have been conducted for the data collection. 90 answers have been analyzed statistically by SPSS 19.0 program. Results: The conclusions of this study are as follows. Firstly, spinal cord disorders prefer diagonal approach and lateral approach to the toilet, but brain lesions prefer diagonal approach and frontal approach to toilet. Secondly, the manual wheelchair users prefer the diagonal approach and the lateral approach to the toilet, and the electric wheelchair users has a different approach way to the toillet depending on the direction of the door. Finally, the layout of accessible toilets have to be designed for the diagonal approach to toilet, which is most preferred by wheelchair users. Implications: The toilet approach varies according to the disability types and the wheelchair types. Therefore, the size of accessible toilets should be larger than now considering the access of variety wheelchair users.

• Journal of the Ergonomics Society of Korea
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• v.12 no.2
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• pp.15-28
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• 1993

Proper ergonomic design of a passenger seat for the highspeed train is one of the essential design components that is directly related to passenger comfort. This study investigated a systematic approach to the ergonomic passenger seat design and evaluation for the Korean highspeed train. To design an ergonomic passenger seat that improves passenger confort, Korean anthropometric data, pas- senger activities in the coach, body postures, body contours and seat dimensions were considered. By analyzing the interredlationship of such factors, resultant seat dimensions were suggested. To properly ecaluate the suggested dimensions, four prototypes were subsequently made and iteratively tested in the laboratory. It is expected that this approach is readily applicable to the passenger seat design of other transport vehicles as well as a train.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.3
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• pp.49-61
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• 2015

We study the problem of multiple response optimization (MRO) and focus on the selection of input levels which will produce desirable output quality. We propose an interactive multiple objective optimization approach to the input design. The earlier interactive methods utilized for MRO communicate with the decision maker only using the response variable values, in order to improve the current response values, thereby resulting in the corresponding design solution automatically. In their interaction steps of preference articulation, no account is taken of any active changes in design variable values. On the contrary, our approach permits the decision maker to change the design variable values in its interaction stage, which makes possible the consideration of the preference or economics of the design variable side. Using some typical value functions, we also demonstrate that our method converges reasonably well to the known optimal solutions.

• Korean Institute of Interior Design Journal
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• v.13 no.4
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• pp.118-126
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• 2004

This study started from the premise that the future elementary school should be designed based on ecological approach in order to restore the emotionality of children. This study aimed at providing a guideline for designing the interior of elementary schools based on ecological approach. Through literature review, the characteristics of ecological architecture and the regulations for green buildings were explored. Also 7 elementary schools which were evaluated as good school design through renowned books representing the ecological characteristics were chosen and analyzed. The results revealed that the school design included natural lighting by roof lighting, natural ventilation, greening, and use of natural materials. This study suggested three categories as a the guideline for the interior space of eco-school design; energy efficiency, greening and sustainability, which included natural lighting, natural ventilation, heating and cooling, planting, materials and water recycling.

• Communications for Statistical Applications and Methods
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• v.13 no.1
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• pp.1-10
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• 2006

Many of statistical experimental designs have multiple goals. It is often impractical to use the single-objective criterion for this purpose. It is necessary to modify the existing optimum experimental design criteria. There exist three criteria handling this problem in general: compound, constrained, maxi-min approach. This paper extends Kahng and Kim's idea to develop another approach to incorporate several experimental design criteria in accordance of their importance in practical way. Furthermore this paper investigate its relationship with the maxi-min approach. It shows logically that the often realized infeasibility can be still avoided with the rank of importance of the objectives intact.

• Korean Management Science Review
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• v.24 no.2
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• pp.73-80
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• 2007

Robust Design(RD) is a cost-effective methodology to determine the optimal settings of control factors that make a product performance insensitive to the influence of noise factors. To better facilitate the robust design optimization, a dual response surface approach, which models both the process mean and standard deviation as separate response surfaces, has been successfully accepted by researchers and practitioners. However, the construction of response surface approximations has been limited to problems with only a few variables, mainly due to an excessive number of experimental runs necessary to fit sufficiently accurate models. In this regard, an innovative response surface approach has been proposed to investigate robust design optimization problems with larger number of variables. Response surfaces for process mean and standard deviation are partitioned and estimated based on the multi-level approximation method, which may reduce the number of experimental runs necessary for fitting response surface models to a great extent. The applicability and usefulness of proposed approach have been demonstrated through an illustrative example.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.646-651
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• 2004

Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, crashworthy design approach is applied to the tilting train express (TIX) design which is newly being developed. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of a TTX design candidate arc evaluated numerically using the finite element method. Finally, design alternatives which show better crashworthy performances are proposed and verified through the full-rake collision simulations.

• Proceedings of the ESK Conference
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• 1993.04a
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• pp.124-133
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• 1993

Porper ergonomic design of a passenger seat for the highspeed train is one of the essential design components that is directly related to passenger comfort. This study investigated a systematic approach to ergonomic passenger seat design and evaluation for the Korean highspeed train. To design an ergonomic passenger seat that improves passenger comfort, seat dimensions, Korean anthropometry, passenger activities in the coach, body postures and body contours were considered. The interrelationship of these factors was analyzed and seat dimensions were suggested. To properly evaluate the dimensions suggested, four prototypes were made and iteratively evaluated as a feedback procedure. This approach is expected to be applicable to the passenger seat design of other transport vehicles as well as a train.