• Journal of the Korean Mathematical Society
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• v.56 no.5
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• pp.1387-1401
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• 2019

Consider a finite measure space (${\Omega}$, ${\Sigma}$, ${\mu}$) and a Banach space $X({\mu})$ consisting of (equivalence classes of) real measurable functions defined on ${\Omega}$ such that $f{\chi}_A{\in}X({\mu})$ and ${\parallel}f{\chi}_A{\parallel}{\leq}{\parallel}f{\parallel}$, ${\forall}f{\in}({\mu})$, $A{\in}{\Sigma}$. We prove that if it satisfies the subsequence property, then it is an ideal of measurable functions and has an equivalent norm under which it is a Banach function space. As an application we characterize norms that are equivalent to a Banach function space norm.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.1
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• pp.59-67
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• 2009

The purpose of this study is to provide a decision support to select an appropriate layered manufacturing(LM) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model far molding, material property, build time and part cost that greatly affect the performance of LM machines. However, the selection of a LM is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate LM machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify LM machines that the users consider After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of LM machines.

• Journal of the Korean housing association
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• v.4 no.1
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• pp.47-55
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• 1993

The research was carried out by posing a questionnaire, making middle and high schoolstudents 549 in Taehu an object of this research, in order to grasp the residential outlook of juveniles.1. The first order of reason why they have resided in present their houses was by a school group and their parents' choice and work place and second order of reason was by their parents' choice, life convenience in present house add traffice convenience And there was littledifference in the first and second residential reasons according to sew.2. In compareson with past and present house type, past and present house type shewed same tendency and future wanted house type was separate house absolutely.3. Points to be considered in selectong future were in the order of facilities, traffice,, surrounding, educational, social and economical circumstances. There was little difference in almost items to be considered in choosing accordant to sew. But in case of schoolgirls, they consisered more items in selecting houses than in schoolboys.4. As a result of researching ideal house of juvenile, happy family was most Preferred and the desire to possess house was expressed strongly.5. The first value on house was health of family, the stability, the stabi]ity and the residential convenience. And schoolboys attacged more importance to the gealth of family, ghe stability and the education fer children than in case of school-girls but on the other hand school girls attached more importance to economical value house and happy and harmonious family.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3139-3145
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• 2014

This paper describes the design of a size-reduced ring hybrid coupler for microwave band using an artificial dielectric substrate(ADS). ADS structure adopts the second substrate on which has lots of the metalized via-holes. The effective capacitance and effective dielectric constant per unit length of ADS increases compared to the normal substrate due to the via-holes. This enables the physical length of microstrip transmission line to be reduced by adopting ADS instead of the normal substrate. In order to present an example of size-reduction of microwave wireless circuit by ADS, a size-reduced 3GHz ring hybrid coupler is designed, fabricated and measured in this work. The designed coupler has the smaller size from the normal one by 65% due to the ADS, while no critical degradation from ideal performances is observed. The measured power division ratio at two output ports are -3.05dB and -3.135dB, respectively. In addition, the phase differences are 3o for in-phase division and 176o for out of phase split. The measured performances are so similar to ideal ones, and prove the design of size-reduced ring hybrid coupler using ADS is successful.

• Journal of Korean Society of Rural Planning
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• v.4 no.1
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• pp.63-74
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• 1998

The objective of this study is the investigation and analysis of information on the conservation and the sustainable use of coastal wetlands based on the awareness of local residents in Kang-hwa island, Tae-an and Seo-chon. The results are summarized as follows: The degree of the satisfaction on the natural environment is in the order of Tae-an, Kang-hwa and Seo-chon. This order is accorded with the order of the goodness of natural environment. The order for the degree of the satisfaction on the living environment is same as the order for the satisfaction degree on the natural environment. Especially, residents of Seo-chon are not satisfied with the living environment. The residents of all regions are not satisfied with the socio $.$ economic environment. The local resident of Kang-hwa and Tae-an, where natural environment is well-conserved, prefer conservation to development of the region. On the other hand, the local residents of Seo-chon have relatively low preference for conservation of the region. These results show the following consideration for the ideal method of management for the conservation and sustainable development of coastal wetlands. In case of Kang-hwa island, where the, condition the natural environment is well conserved, should be managed with the minimum development with maintenance of the current state must be driven.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.115-130
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• 1995

The National Geographic Institute(NGI), a national mapping agency, has begun to digitalize national base maps to vitalize nation-wide GIS implementations. However, the NGI's cartographic database design reflects only paper map production and is considered inflexible for various applications. In order to suggest an appropriate data model and database implementation method, approaches of two mapping agencies are analyzed: the United State Geological Survey and Ordnance Survey in the United Kingdom One important finding from the analysis is that each data model is designed to achieve two production purposes in the same time : map and data. By taking advantageous features from the two approaches, an ideal model is proposed. To adapt the ideal model to tile present situation in Korean GIS community, a realistic model is generated, which is an 'SDTS-oriented' data model. Because SDTS will be a Korean data transfer standard, it will be a common basis in developing other data models for different purposes.

• Journal of Korean Society of Transportation
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• v.4 no.1
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• pp.12-27
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• 1986

This study examined user preferences toward transportation modes in Seoul. Two multidimensional scaling models, the ideal point and vector models, were applied to data on mode preferences of 114 adults in the metropolitan area. While both models produced fairly similar results, the vector model performed slightly better than the other in terms of interpretability of the results. The transport attributes elicited are comfort, flexibility, travel cost, travel time, privacy, and safety; among which comfort is salient most. The comfort variable is a multi-faceted attribute in nature. The variations of attribute preferences are most significant between the gender groups as well as worker/nonworker groups. In particular, male workers, female workers and female nonworkers form three distinctive market segments. An unidimensional scaling of the preference data reveals that subway, auto-driver, and subscription bus modes are preferred most, whereas motorcycle and bicycle least. The other modes of express bus, taxt, auto-passenger, bus and walk rank intermediately. An examination of how preference orders vary among modal groups hints that users align their stated attitudes to their choice in order to reduce cognitive dissonance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.103-110
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• 2003

A hybrid structural reliability analysis method that integrates a commercial finite element program and a reliability analysis algorithm is proposed to estimate the safety of real structures in this paper. Since finite element method (FEM) is most commonly and widely used in the analysis and design practice of real structures, it appears to be necessary to use general FEM program in the structural reliability analysis. In this case, simple conventional reliability methods cannot be used because the limit state function can only be expressed in an algorithmic form. The response surface method(RSM)-based reliability algorithm with the first-order reliability method (FORM) found to be ideal in this respect and is used in this paper. The intention of use of RSM is to develop, albeit approximately, an explicit expression of the limit state function for real structures. The applicability of the proposed method to real structures is examined with help of the example in consideration of a concrete dam. Both the strength and serviceability limit states are considered in this example.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.2
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• pp.72-77
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• 2002

In this paper, a simple method to measure the residual stress in microstructure is presented. In order to find the residual stress in micro-machined beam, the first natural frequency of the beam that has the residual stress inside is analyzed using Rayleigh's energy method. Micro gold electroplated structure is fabricated by surface micro-machining process including electroplating. The made structure is an approximate shape of clamped-clamped beam and its 1 st natural frequency is measured by resonance method. For the better estimation of the residual stress, an equivalent length of micro-fabricated beam to ideal beam is calculated by FEM. The residual stress was estimated from the equivalent length and the measured natural frequency. It was found that a tensile stress was residue in the micro beam structure.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.521-525
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• 2009

Solar, as an ideal renewable energy, has inexhaustible, clean and safe characteristics. However, solar energy is an extreme intermittent and inconstant energy source. In order to improve the photovoltaic system efficiency and utilize the solar energy more fully, and the DC current vary with the irradiation, it is necessary to study the characteristics of photovoltaic I-V according to the external factors. This paper presents the analysis of characteristics of photovoltaic I-V according to the irradiation. The results show that the DC current of the photovoltaic system are increased along with the increasing values of irradiation.