• 대한수학회보
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• 제59권2호
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• pp.303-318
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• 2022

n-writhes denoted by J_n(K) are virtual knot invariants for n ≠ 0 and are closely associated with coefficients of some polynomial invariants of virtual knots. In this work, we investigate the variations of J_n(K) under arc shift move and conclude that n-writhes J_n(K) vary randomly in the sense that it may change by any random integer value under one arc shift move. Also, for each n ≠ 0 we provide an infinite family of virtual knots which can be distinguished by n-writhes J_n(K), whereas odd writhe J(K) fails to do so.

• 한국지역지리학회지
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• 제13권6호
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• pp.651-673
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• 2007

본 연구에서는 이동 유형을 지역 내 이동과 지역 간 이동으로 구분하여 각각의 원인을 고찰하는 한편 두 가지 유형의 상호 연계성을 이동 후 관찰되는 자가소유에 기초하여 분석하였다. 본 연구에서는 통계청에서 제공하는 1980년부터 2000년까지의 인구주택총조사(Census)를 활용해 우리나라 인구이동의 일반적 특성을 고찰하고 기존의 이동거리에 관한 가설을 검증하는 한편, 이동형태에 따른 자가소유의 결정요인을 분석하였다. 분석 결과 지역 간 이동과 지역 내 이동의 연계를 밝혀주는 Goodman의 세 가지 가설과 Roseman의 조정이동 가설은 우리나라에서 대부분 성립하지만 이러한 경향은 감소하는 추세인 것으로 나타났다. 이동거리에 따른 이주경력 결정요인을 살펴보면 연령이 낮을수록, 차가 거주자일수록, 교육수준이 높을수록, 가구원수가 적을수록 이동성향이 증가했다. 시간이 경과함에 따라 여성의 반복이동 성향이 증가하며 유배우자의 이동성향은 감소하였다. 단거리 이동의 경우여성의 이동성향이 남성에 비해 우세했다. 지역적 특성을 고려하기 위해 통제된 변인 중 보다 앞선 시기에 실업률이 부(-)인 지역으로 향하던 이주가 조사시점과 가까운 시기에는 정(+)인 지역으로 변화한 점과, 교원수 변인이 동일시기 정(+)인 지역에서 부(-)인 지역으로 변화한 점은 주목할 만하다. 이주 후 자가를 소유할 확률은 지역 간 이동에서 여성이 더 높았으며 연령이 증가할수록 확률이 증가하는 것으로 나타났다. 직업유형별로 살펴보면 판매직과 기능적의 경우 이동 후 자가를 소유할 확률이 가장 낮았으며 전문직 종사자는 가장 높은 확률을 보였다. 제주지역으로 이주한 가구가 타지역 이주가구에 비해 자가소유확률이 낮았으며 지가가 높은 지역을 목적지로 택한 가구일수록 자가소유 경향은 낮아졌다. 이동성향이 높은 가구는 자가소유 가능성이 낮은 것으로 나타났다.

• Journal of Mechanical Science and Technology
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• 제19권2호
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• pp.674-681
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• 2005

The unsteady evolution of trailing vortex sheets behind wings in close formation flight near the ground is simulated using a discrete vortex method. The ground effect is included by an image method. The method is validated by comparing computed results with other numerical results. For a lifting line with an elliptic loading, the ground has an effect of moving wingtip vortices laterally outward and suppressing the development of vortex evolution. The gap between wings in close formation flight has an effect of moving up wingtip vortices facing each other. For wings flying in parallel, the ground effect causes the wingtip vortices facing each other to move up, and it makes the opposite wing tip vortices to move laterally outward. When there is a relative height between the wings in ground effect, right-hand side wingtip vortices from a mothership move laterally inward.

• ETRI Journal
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• 제40권5호
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• pp.653-663
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• 2018

Patients with spinal cord injuries cannot move their limbs using their intact muscles. A suitable controller can be used to move their arms by employing the functional electrical stimulation method. In this article, a fuzzy exponential sliding-mode controller is designed to move a musculoskeletal human arm model to track an optimal trajectory in the sagittal plane. This optimal arm trajectory is obtained by developing a policy for the central nervous system. In order to specify the optimal trajectory between two points, two dynamic and static optimal criteria are applied simultaneously. The first dynamic objective function is defined to minimize the joint torques, and the second static optimization is offered to minimize the muscle forces at each moment. In addition, fuzzy logic is used to tune the sliding-surface parameter to enable an appropriate tracking performance. Simulation results are evaluated and compared with experimental data for upward and downward movements of the human arm.

• Architectural research
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• 제15권2호
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• pp.77-86
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• 2013

Cohousing is based on collaborative network, or fictive kin in the community. It could facilitate the goal of self-sufficiency. This research aims to investigate the motivation of move to cohousing communities in Sweden, and to find out if there are any significant differences according to two different cohousing types; between the +40 cohousing and the mixed-age cohousing. The +40 cohousing is a kind of senior cohousing in which residents are supposed to be aged over 40. Questionnaire survey was applied and 242 collected data were analyzed by SPSS statistical program. Notable differences in demographic and dwelling variables are found between the 2 groups. There are more women, singles, academics, and small dwellings in the +40 cohousing than in the mixed-age cohousing. Referring motivation of move, "sharing common activity" and "idea of cohousing" are commonly noticed as the main reasons why people move to cohousing communities. Major difference between the 2 groups is that residents of the +40 cohousing tend to stress more on social interaction with neighbors than practical merit. On the contrary, ones of the mixed-age cohousing focus more on practical advantage than social interaction. As a conclusion, it is evident that motivation of move to cohousing communities is different by cohousing types, which have different residents' characteristics. Cohousing could contribute to elevate marginal group's quality of life as an alternative living environment. Therefore, cohousing design has to be tailored to adapt residents' specific needs of different life-stages. In order to implement cohousing model into other countries, for instance into Korea, it needs to experiment with the notion of transplanting selected cohousing principles to a public housing development. In the mixed-age cohousing where more dual income families with young children than conventional housing developments reside, residents would need more practical advantage than emotional support in the community, while as residents in the senior cohousing need vice versa.

• 한국주거학회논문집
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• 제25권4호
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• pp.125-133
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• 2014

The purpose of this study was to find the role of participation in common activities and satisfaction with common space in a tentative housing adjustment framework for Swedish cohousing residents, applying the housing adjustment behavior model of Morris and Winter (1978, 1996). The data used for this research were a subset of data Choi and Paulsson (2011) surveyed from 12 Swedish cohousing units. Number of 216 cases whose age was 40 and over were selected and analyzed with Pearson correlations and hierarchical linear regressions by SPSS. The regression analyses included four main concepts as endogenous variables, which were participation in common activities, satisfaction with common space, overall life satisfaction, and intention to move out. The results showed that participation in common activities raised satisfaction with common space and overall life satisfaction but reduced intention to move out. Meanwhile, satisfaction with common space diminished intention to move out but did not impact overall life satisfaction. When overall life satisfaction was added to the final regression model, the direct impacts of security reasons, participation in common activities, and satisfaction with common space on intention to move out disappeared. It may be concluded that participation in common activities and satisfaction with common space acted as intervening variables in the tentative cohousing adjustment framework. Even though this study leaves further research on specifying the framework, it may be noteworthy as a first attempt that explains the flow of main concepts. This study may broaden the possibility of empirical studies to develop an analytical path model of housing adjustment for cohousing residents.

• Wind and Structures
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• 제3권4호
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• pp.291-302
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• 2000

A new finite element technique to solve the problem of wind and structure interactions is presented. Conventionally, wind analysis is performed on the Eulerian description in which the finite element mesh would not move in accordance with the wind flow. However, it is not the case in wind-structure interaction problems because nodes attached to the surface of structure should move with the displacement of structure. The arbitrary Lagrangian-Eulerian (ALE) method treats the mesh and flow independently, and allow the mesh to move. In this study, the analysis domain is divided into regions of the structure, air around the structure and the interface of two regions. To satisfy the compatibility and equilibrium conditions between separated regions and to carry out the efficient analysis, the rigid link is used. Also the equation of wind and that of structure are arranged in a single matrix equation.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1179-1182
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• 2011

RC servos are electro-mechanical devices that respond to a control signal, which instructs them to move their output shaft to a certain position. A servo is normally plugged into a radio receiver with a three pin connector. The three wires are a power (usually 4.8V to 6.0V), a ground, and a signal wire. The signal wire carries a PWM (Pulse-Width Modulation) signal consisting of a 1-2msec pulse repeated 50 times a second. A 1.5msec pulse will tell the servo to move to its output shaft to the center position, 0 degrees. For a servo with a 180 degree of motion, a 1msec pulse will move the servo to -90 degrees, and a 2msec pulse will move the servo to +90 degrees. In order to development a humanoid robot, mechanical design, fixtures design, analysis of kinematics, implementation moving program, selection of RC servo motor and controller are required. This study was performed to experimentally compare the rotation range of RC servo motors according to change of a periods.

• 한국주거학회논문집
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• 제25권5호
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• pp.73-82
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• 2014

The purpose of this study is to identify U.S. Baby Boomers' intention to move and their reasons for moving after retirement, and to examine the associations between their socio-demographic characteristics and housing characteristics, and their reasons for moving after retirement factors. A total of 403 usable data were collected through an online survey using a self-administrated questionnaire. For data analyses, descriptive statistics, factor analysis, t-test, and ANOVA were used. Almost 30% of the total respondents considered moving and 15% were strongly agreed to move after their retirement. The most frequently mentioned reasons for moving after retirement were 'a place with good weather', 'being close to leisure activities', and 'a change or decline of my current neighborhood'. Four factors of reasons for moving after retirement (quality of residential environment, need assistant, proximity to activities, and proximity to family/friends) were identified. Age, marital status, number of household, housing type, homeownership, length of residence, and number of bedroom were significantly associated with the four factors of reasons for moving. The results of this study provide a better understanding to U.S. Baby Boomers' housing behavior after retirement which is 10 years faster than Korea, and suggest insights of housing plan for Korean older adults.

• 한국게임학회 논문지
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• 제17권3호
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• pp.63-70
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• 2017

인공지능 연구에서 바둑은 위치평가의 어려움과 엄청난 분기수로 인해 가장 도전적인 보드게임으로 여겨지고 있다. 몬테카를로 트리탐색은 이러한 문제점을 극복할 수 있는 고무적인 돌파구이다. 알파고의 숨겨진 아이디어는 주어진 위치에서의 승률을 예상하여 깊은 탐색을 유도한 후 가장 고무적인 착수를 찾아내는 것이었다. 본 논문에서는 무전략 MCTS를 활용하여 9줄바둑에서 프로기사들이 최상의 첫수로 여기는 천원점이 옳다는 것을 확인했으며, 또한 가장 유행하는 첫 수들의 평균승률을 비교했다.