• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.47-52
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• 2018

In this study, a collimator composed of multi-dielectric structures is designed using the phase field design method, a kind of topology optimization methods. It is also purposed to improve the mechanical-structural performance of a collimator by replacing previously used air regions with another dielectric material. Polypropylene and paraffin are selected as the dielectric materials for the design process taking manufacturability into account. The design objective is formulated by integrating the intensity of the electromagnetic field in the pre-determined target area to realize the collimating performance. The model for accurate numerical analysis was derived from the final result obtained from the design process through the simple cut-off method and it shows the improved performance of 105% compared with the free space wave propagation. For the designed model, the possibility of reverse transformation, the mechanical durability evaluation under the compression load, and the electromagnetic performance in the X-band range were also evaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.956-963
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• 2002

In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed according to rapidly upgrade their related technologies. Generally stay cables as a critical member need to be rearranged for being satisfied with design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted on existing stay cables. In this study, cable vibration tests were tarried out to evaluate the cable tension forces comparing with theoretical and practical formulas. Using the measured frequencies obtained from free vibration and Impulsive tests, an accuracy of the estimated tension forces is confirmed according to use the first single mode only or higher multiple modes.

• Korean Institute of Interior Design Journal
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• v.16 no.6
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• pp.47-55
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• 2007

The purpose of this study is to evaluate environmental characteristics of maternity rooms. The method of this study is a field survey on 8 samples of postpartum care centers in Seoul. The plan, colors, materials, furniture and environmental characteristics of maternity rooms are analyzed. The characteristics of maternity rooms environment were categorized into four items; comfort, privacy, communication and dwelling. The results are as follows: Western-style and rooming-separation system of maternity rooms are used. Maternity rooms are generally good for dwelling quality but insufficient for communication. There are a lack of supply to control a temperature Individually in maternity rooms. It demands to make the type of one-sided public space between maternity room and living room for privacy. All of the maternity rooms surveyed are furnished with TV, radio, and telephone but, to improve communication with visitors, it is recommended that more convenient supplies such as audio and video system, chairs, and table be equipped. There are needs for sky-light windows in maternity rooms. It is necessary to research more about the space of living room, nursing room and service area, and we need more study about baby, nurser and owner' spaces.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.1
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• pp.1-10
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• 2005

An aerodynamic shape optimization technique has been developed for helicopter rotor blades in hover based on a continuous adjoint method on unstructured meshes. The Euler flow solver and the continuous adjoint sensitivity analysis were formulated on the rotating frame of reference for hovering rotor blades. In order to handle the repeated evaluation of the design cycle efficiently, the flow and adjoint solvers were parallelized using a domain decomposition strategy. A solution-adaptive mesh refinement technique was adopted for the accurate capturing of the tip vortex. Applications were made for the aerodynamic shape optimization of Caradonna-Tung rotor blades and UH60 rotor blades in hover. The results showed that the present method is an effective tool to determine optimum aerodynamic shapes of rotor blades requiring less torque while maintaining the desired thrust level.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.370-379
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• 2011

The increasing complexity of complex buildings, such as high-rise buildings and underground subway stations, presents new challenges to firefighters. In a fire in complex buildings, the importance of the collaboration between firefighters is clear. The increased demand on firefighter training for such environment is now evident. Due to cost, time, and safety issues, it is impossible to experience a real fire in such environments for training. In addition, the use of real fire for training does not enable repeatable training and the evaluation of the training is difficult. We developed a team-based firefighter training simulator for complex buildings using the virtual reality technology. It provides the training and evaluation of firefighting and mission-based team training. To model real fire phenomena in virtual space, a numerical analysis method based on fire dynamics is used. To achieve an immersive virtual environment, an augmented reality technique for the compensation of real world image and a haptic technique for heat experience are adopted. The developed training simulator can help the firefighter to respond to large and complex firefighting scenarios, while maintaining the safety of the trainees.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.81-87
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• 2009

Computer simulation of buildings and solar energy systems is being used increasingly in energy assessments and design.. Building designers often now predict the performance of buildings simulation programmes that require hourly weather data. However, not all weather stations provide hourly data. Climate prediction models such as HadCM3 also provide the daily average dry bulb temperature as well as the maximum and minimum. Hourly temperature values are available for building thermal simulations that accounts for future changes to climate. In order to make full use of these predicted future weather data in building simulation programmes, algorithms for downscaling daily values to hourly values are required. This paper describes a more accurate method for generating hourly temperature values in the South Korea that uses all three temperature parameters from climate model. All methods were evaluated for accuracy and stability in terms of coefficient of determination and cumulative error. They were compared with hourly data collected in Seoul and Ulsan, South Korea.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.4
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• pp.61-68
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• 2019

As high schools implement credit completion system these days, concerns about the dissolution of classes, which are the original stable groups of studying and living, and the instability of the basal space, is growing due to the extended operation of moving optional classes. The purpose of this research is to understand the effect that environmental features of the basal space within the school and the operation method have on the students' space use and formation of attachment place within the school. For this, the main activity places, attachment places, school life satisfaction and others were investigated at 2 Japanese credit-based comprehensive high schools, which are different in the physical environmental features of school buildings. Based on this, a quantitative analysis about the distribution of activity places and attachment places was implemented. The space use features for each student attribute were compared, and the school life satisfaction for each type of attachment place formation was analyzed. As a result, the change of the territorial consciousness about the class space according to the implementation of moving optional classes could be understood. And it was confirmed that the students' space using behavior and place evaluation change according to the physical environmental feature of the class space and common space, and that this is affecting the life satisfaction of students.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.312-320
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• 2012

In this study, we introduce a new design methodology of a granular-oriented self-organizing polynomial neural networks (GoSOPNNs) that is based on multi-layer perceptron with Context-based Polynomial Neurons (CPNs) or Polynomial Neurons (PNs). In contrast to the typical architectures encountered in polynomial neural networks (PNN), our main objective is to develop a methodological design strategy of GoSOPNNs as follows : (a) The 1st layer of the proposed network consists of Context-based Polynomial Neuron (CPN). In here, CPN is fully reflective of the structure encountered in numeric data which are granulated with the aid of Context-based Fuzzy C-Means (C-FCM) clustering method. The context-based clustering supporting the design of information granules is completed in the space of the input data while the build of the clusters is guided by a collection of some predefined fuzzy sets (so-called contexts) defined in the output space. (b) The proposed design procedure being applied at each layer of GoSOPNN leads to the selection of preferred nodes of the network (CPNs or PNs) whose local characteristics (such as the number of contexts, the number of clusters, a collection of the specific subset of input variables, and the order of the polynomial) can be easily adjusted. These options contribute to the flexibility as well as simplicity and compactness of the resulting architecture of the network. For the evaluation of performance of the proposed GoSOPNN network, we describe a detailed characteristic of the proposed model using a well-known learning machine data(Automobile Miles Per Gallon Data, Boston Housing Data, Medical Image System Data).

• Journal of Digital Convergence
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• v.20 no.5
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• pp.919-929
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• 2022

As a new type of healthy public space, greenway users carry out leisure activities, exercise, sightseeing and necessary transportation in greenway. However, at present, there is little research on greenway users' evaluation and perception of greenway, and there is no comprehensive exploration of Greenway environment from a humanistic perspective. Combined with the research and actual situation of the existing representative greenways in Chinese cities, this paper refers to a large number of documents, applies the semantic difference method and multiple regression analysis method, analyzes the current situation of the Dongfengqu greenway, explores the influencing factors and impact evaluation of the greenway environment from the perspective of greenway users' perception, and puts forward suggestions on the optimization of the greenway environment in Zhengzhou from multiple levels. The main conclusion of this paper comes from the data conclusion obtained by semantic difference method, which is feasible in the resident evaluation of greenway use. The feedback results of post use evaluation can provide a reliable reference for the planning and design of similar greenways in the future.

• Fashion & Textile Research Journal
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• v.7 no.2
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• pp.225-230
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• 2005

This research was undertaken to compare basic bodice prototypes for Internet shopping customer, and to select a profitable fit vacant space quantity between clothing and body. A total one hundred of eighteen outfits (4 types of pattern ${\times}$ 9 subjects ${\times}$5 body areas) were constructed with basic bodice drafting method of Japan Bunka Women's University according to nine male body types. Fifty-two experts analysis of the different prototypes as five body area and evaluate the most appropriate ease amount and stabilization of the simulation images on the computer. The experiments with automated methods using simulation image are based on AZ program of TORAY, Japan. Data was analyzed using percentiles, frequency and $X^2$. Taken together, the present result of vacant space quantity and stability evaluation through images shows that there is a significant difference in the size variation of the chest circumference, shoulder slope and waist circumference. In case of ease amount, chest area, shoulder slope, waist area and armhole except neckline area were shown more appropriate on the basic bodice pattern without size change. In case of stabilization, the chest area, shoulder slope and armhole except waist area and neckline area was shown the best on the basic bodice pattern without size change. However the waist area was shown on the basic bodice pattern plus 2 cm, neckline was shown more appropriate on the basic bodice pattern plus 1cm.