• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.368-373
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• 2005

This paper presents a new framework for the traffic flow control based on integrated model descriptions as the Hybrid Dynamical System (HDS).

• The Pure and Applied Mathematics
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• v.17 no.4
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• pp.373-388
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• 2010

We introduce mixed cubic-quartic functional equations. And using the fixed point method, we prove the generalized Hyers-Ulam stability of cubic-quartic functional equations on random normed spaces.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.735-747
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• 2019

Due to the lack of ground space by urbanization, the demand of utility tunnels for laying social facilities is increasing. During the construction of a utility tunnel in downtown area using a shield TBM, various problems may occur when difficult ground is encountered such as mixed ground and cobbly ground. Thus, in this study, using MIDAS GTS NX (Ver. 280), a numerical analysis was performed on characteristics of difficult ground, reinforced area, depth of cover and groundwater level to analyze the optimal ground reinforced area according to combination of parameters. As a result, it was difficult to secure stability in unconstrained excavation cases on both the mixed ground and the cobbly ground. However, when ground reinforcement grouting as much as 2.0D is applied, convergence occurred within the allowable limit, except for mixed ground with a depth of cover 30 m. In addition, excessive leakage occurred during excavation of both the mixed ground and the cobbly layers. It was able to secure stability after applying waterproof grouting.

• Journal of architectural history
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• v.24 no.4
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• pp.19-28
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• 2015

This study examines the Singapore public housing supplied by Singapore Improvement Trust (SIT) in the 1950s. Focused on the Princess Elizabeth estate and Princess estate of Queenstown, this study surveys their construction backgrounds, site plans, unit plans, architectural designs and meanings. The Princess Elizabeth estate was the model estate for workmen's flats. This estate showed mixed blocks of flats arranged around a large quadrangled open space for children. The Princess estate was a neighborhood of Queenstown, Singapore's the first new town. At this Estate, there were some new architectural occurrences departing from the Tiong Bahru Estate. Those are the appearance of high-rise typology, and the increased specificity in the functions of open spaces. Thus the open space became to get hierarchy, and divided an estate to small neighborhood units. For the SIT, open space is synonymous with the improvement of urban environment. Through the purposeful creation of open space, the SIT intended to solve the problem of sanitation and to make a neighborhood unit which can be pleasant place for regional community.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.35-41
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• 2005

The problem of an orthotropic composite material with a central crack inclined with respect to the principal axes of material symmetry is studied. The material is subjected to uniform biaxial loading along its outer boundaries. The normal stress ratio theory is applied to predict initial crack extension behavior in cracked composite materials. The dependence of the crack extension angle with respect to the biaxial loading and the principal axes of material symmetry is discussed. Our analysis shows significant effects of horizontal loading, crack angle and fiber angle on the crack extension.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.684-692
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• 2010

Based on the planar restricted three body problem formulation, optimized trajectories for the Earth-Moon transfer are obtained. Mixed impulsive and continuous thrust are assumed to be used, respectively, during the Earth departure and Earth-Moon transfer/Moon capture phases. The continuous, dynamic trajectory optimization problem is reformulated in the form of discrete optimization problem by using the method of direct transcription and collocation, and then is solved using the nonlinear programming software. Representative results show that the shape of optimized trajectory near the Earth departure and the Moon capture phases is dependent upon the relative weight between the impulsive and the continuous thrust.

• Human Ecology Research
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• v.54 no.2
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• pp.131-139
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• 2016

This study analyzes the welfare services and spatial composition of social welfare centers that represent complex welfare facilities in order to provide basic information for the spatial planning of social welfare centers. We examined 15 social welfare centers built in the 2000s. A literature review and case study were used as research methodology. The findings are as follow. First, services provided at the surveyed facilities overlapped for seniors and the handicapped. Most social welfare centers provided welfare services for seniors, young children, and teenagers. Second, the proportion of common area, program rooms was high for spatial composition. Third, front access by car was most common (used at nine centers) for the design of the access area and used by. Fourth, shared entry and exit was most common (used at 10 centers) for the design of the entrance. Fifth, regarding space combining style, a mixed style was most frequently used (observed at seven centers) where different private areas for different service users were partly mixed on certain floors. Sixth, a corridor type was most common (used at seven centers) for the design of a corridor space where visitors could walk along the corridor to access individual rooms. Based on the findings, we propose spatial composition of social welfare centers to promote mingling and exchanges among users of different generations.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.454-460
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• 2003

In this paper, we present a novel method of parallelization of the modular multiplication algorithm to improve time and space complexity on RNS (Residue Number System). The parallel algorithm executes modular reduction using new table lookup based reduction method. MRS (Mixed Radix number System) is used because algebraic comparison is difficult in RNS which has a non-weighted number representation. Conversion from residue number system to certain MRS is relatively fast in residue computer. Therefore magnitude comparison is easily Performed on MRS. By the analysis of the algorithm, it is known that it requires only 1/2 table size than previous approach. And it requires 0(ι) arithmetic operations using 2ㅣ processors.

• Journal of Engineering Education Research
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• v.25 no.2
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• pp.32-41
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• 2022

The purpose of this study was in a pandemic situation caused by COVID-19 to explore the online distance experiments and interaction of engineering freshmen, and to identify practical difficulties, resulting in to derive implications. Seven freshmen from engineering college participated in the interview, of which data were analyzed based on phenomenological analysis methods. The types of non-face-to-face experiments experienced by students were complete non-face-to-face experiment, mixed face-to-face experiment, and fusion face-to-face experiment. Students were completely isolated in time and space in complete non-face-to-face experiment. In biweekly mixed face-to-face experiment, isolation was halved. In fusion face-to-face experiment, isolation was removed. Non-face-to-face interactions can be characterized by restrictions on simultaneous activities, on rapport formation, and on observation opportunities. Based on these results, three implications were derived: First, it is necessary to allow students to manage time and space constraints on their own in non-face-to-face experiments. Second, support is needed to solve the difficulty of forming rapport, which is a characteristic of non-face-to-face interaction. Third, an opportunity to observe the interaction between other students and professors should be provided.

• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.197-212
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• 2020

In this study, POE(Post Occupancy Evaluation) evaluation indexes were selected into six categories through the consideration of theories and prior research. Therefore, qualitative supply can be achieved through POE according to the aspect of residential environment after the quantitative supply of mixed-use apartment complex by the population concentration in Seoul due to industrialization and urbanization. As the evaluation elements, detailed survey contents were selected for livability, convenience, comfort, safety, economy, and sociality. Based on the survey contents, six elements were evaluated and analyzed using Data coding and Likert scale after surveying 12 complexes (Urban areas and non-urban areas) in Seoul. As a result of the study, six categories selected as the POE showed that importance of quality of life and safety was developed in high recognition according to high satisfaction with convenience and safety. Sociality showed the lowest satisfaction in the following order : livability, comfort, economy and sociality. Residents' sense of community, interaction with neighborhood, etc., showed low satisfaction, and it seems that it is necessary to improve and supplement the system for the development of mixed-use apartment complex in the future. The detailed characteristics of livability showed high satisfaction of the living room, the front door and the main room which are main uses of housing, and low satisfaction in storage size. The analysis of convenience is that convenient public transportation was the highest, and educational environment and additional facilities were the lowest, showing the advantages and disadvantages of location characteristics. As a result of the analysis of comfort, satisfaction with the landscape area was low and it seems that green space is needed for the development of mixed-use apartment complex in the future. Lastly, regarding the safety, the satisfaction of the access control, the location of security office, etc. were high, however separation of circulation was low. Therefore, it is necessary to clearly separate the circulation between the residence and other facilities in the mixed-use apartment complex.