• ETRI Journal
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• v.38 no.2
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• pp.314-325
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• 2016

This paper examines the resource gain that can be obtained from the creation of clusters of nodes in densely populated areas. A single node within each such cluster is designated as a "hotspot"; all other nodes then communicate with a destination node, such as a base station, through such hotspots. We propose a semi-distributed algorithm, referred to as coordinated cognitive tethering (CCT), which clusters all nodes and coordinates hotspots to tether over locally available white spaces. CCT performs the following these steps: (a) groups nodes based on a modified k-means clustering algorithm; (b) assigns white-space spectrum to each cluster based on a distributed graph-coloring approach to maximize spectrum reuse, and (c) allocates physical-layer resources to individual users based on local channel information. Unlike small cells (for example, femtocells and WiFi), this approach does not require any additions to existing infrastructure. In addition to providing parallel service to more users than conventional direct communication in cellular networks, simulation results show that CCT can increase the average battery life of devices by 30%, on average.

• Journal of architectural history
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• v.29 no.6
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• pp.79-88
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• 2020

During the Joseon Dynasty, the rituals that were celebrated in the palaces were mainly held inside the palace and in the courtyard of the palace. Mats were spread on the floor of the place where the ritual was held. The mats spread in the Joseon Dynasty rituals divided the space in various ways, and in particular, they were spread in a certain form in the spaces of royal wedding, customs, and court banquet. Mats were the primary physical element that divided the royal ritual space of the Joseon Dynasty, and functioned to elevate the general space to the ritual space. In the ritual space, mats were spread inside the palace, and divided the courtyard of the palace into left and right in a symmetrical form to distinguish the hierarchy of the participants. Mats with special and white patterns were spread in the external ceremonial space and mats with flower and colorful patterns were spread in the internal ceremonial space. This was the subdivision of the Confucianism's male-female division through the mat. The pattern of the mat that divided the space of the royal family elders also meant longevity to reflect the filial thoughts of the Confucianism through the mat. Mats were a physical element for subdividing the royal family and the participants in the hierarchy of the space where the ritual is held, and it also performed a subdividing function between the royal participants. In other words, in the Joseon Dynasty ritual space, mats were temporarily spread while the ritual is being celebrated and functioned to elevate the space to a ritual space. It is confirmed that the fact that the mats were temporarily spread to divide the space into the hierarchies according to the status and were subdivided into colors and patterns to perform the function to reflect the subdivision of the royal family according to Confucianism and the statue of filial piety in the ritual.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1211-1215
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• 2003

Accurate mathematical models of spacecraft components are an essential of spacecraft attitude control system design, analysis and simulation. Gyro is one of the most important spacecraft components used for attitude propagation and control. Gyro errors may seriously degrade the accuracy of the calculated spacecraft angular rate and of attitude estimates due to inherent drift and bias errors. In order to validate this model, nominal case simulation has been performed and compared for the low range mode and high range mode, respectively. In this paper, a mathematical model of gyro containing the relationships for predicting spacecraft angular rate and disturbances is proposed.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.635-641
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• 2005

This paper presents an ASF (Aluminum Space Frame) BIW (Body in White) optimal design, which minimizes weight and satisfies multidisciplinary constraints such as static stiffness, vibration characteristics, low-/high-speed crash, and occupant safety. As only one cycle CPU time for all the analyses is 12 hours, the ASF design having 11-design variable is a large scaled problem. In this study, ISCD-II and conservative least square fitting method were used for efficient RSM modeling. Likewise, the ALM method was used to solve the approximate optimization problem. The approximate optimum was sequentially added to remodel the RSM. The proposed optimization method uses only 20 analyses to solve the 11-design variable problem. Moreover, the optimal design can achieve $15.6\%$ weight reduction while satisfying all the multidisciplinary design constraints.

• Korean Institute of Interior Design Journal
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• no.13
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• pp.78-88
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• 1997

The objective of this study is to analyze the residential space as designed by Richard Meier thereby grasping its main characteristics and historical development. Richard Meier has developed his own peculiar architecture based on Modernism. He has solved problems of modern architecture by combining the form elements of Le Corbusier with Mies van der Rohe's architecture which pursued the beauty of structure and proportiov. Meier's houses, sculpture-like in forms, are characterized by clear distinction and variations of the interior spaces. The clear separation between a large, two-story high living room and a tiny, cozy bedroom securing the privacy, endows the interions with variation and vitality, while simple white walls reveal the good shape of the space. The houses also unfold the diverse spaces one after another as one steps into inside. His interiors, shaped by simple walls and settled functionally, has inherited the rationality in modern architecture. Richard Meier has established his independent working world by applying his own design method and languages based on the rationality in Modernism.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.59-64
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• 1998

Kim & Beuermann (1995, 1996)have developed a model for the propagation of X-rays from the accreting white dwarfthrough the infalling material and the re-emission of the energy deposited by photo-absorption in the optical (and UV) spectral range. By using this model, we calculate the profiles of the $H_{\gamma}$ emission-line spectrum of intermediate polars. Photoabsorption of X-ray by the infalling material is the dominant process in forming the observed energy-dependent rotational modulation of the X-ray flux. X-ray and optical modulations are sensitive to model parameters in different ways. In principle, these dependencies allow us to obtain improved insight into the accretion geometry of the intermediate polars. We present results of our calculations and compare them with the $H{\beta}$ line spectrum(Kim & Beuermann 1996).

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.3
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• pp.77-83
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• 2009

Van Doesburg founded the magazine De Stijl with Mondrian in 1917. De Stijl movement was influenced by Cubist painting as well as by the mysticism and the ideas about ideal geometric forms in the neoplatonic philosophy. De Stijl proposed ultimate simplicity and abstraction by using only straight horizontal and vertical lines and rectangular forms. Furthermore, their formal vocabulary was limited to the primary colours, red, yellow, and blue, and the three primary values, black, white, and grey. The works avoided symmetry and attained aesthetic balance by the use of opposition. Vertical and horizontal lines are positioned in layers or planes that do not intersect, thereby allowing each element to exist independently and unobstructed by other elements In 1924 their different concepts about space and time were split between Van Doesburg and Mondrian. Van Doesburg launched a new concept for his art, Elementarism, which was characterized by the diagonal lines and rivaled with Mondrian's Neo-Plasticism. The works of De Stijl would influence the Bauhaus style and the international style of architecture.

• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.48-54
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• 2006

White-light scanning interferometry (WLI) and phase shifting interferometry (PSI) are increasingly used for surface topography measurements, particularly for areal measurements. In this paper, we compare surface profiling results obtained from above two optical methods with those obtained from stylus instruments. For moderately rough surfaces ($Ra{\approx}500\;nm$), roughness measurements obtained with WLI and the stylus method seem to provide close agreement on the same roughness samples. For surface roughness measurements in the 50 nm to 300 nm range of Ra, discrepancies between WLI and the stylus method are observed. In some cases the discrepancy is as large as 109% of the value obtained with the stylus method. By contrast, the PSI results are in good agreement with those of the stylus technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1364-1369
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• 2012

We make an analysis of maximum allowable transmission output level to get the solution how heterogeneous systems between adjacent channels can be used in TVWS(TV White Space). The two applied systems are WLAN and WiBro and the overall performances are analyzed based on simulation results according to various density and transmission output of interfering transmitter. In order to get the relationship between interfering density of two systems and allowable maximum transmitter output, we consider the case that a WLAN is an interfering transmitter and a WiBro is a victim receiver. Each simulation results, obtained by free space channel model, are analyzed by SEAMCAT. Coexistence results may be widely applied into the technique development to get the coexisting condition for wireless devices using many communication protocols in an adjacent frequency and a same frequency.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.187-193
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• 2011

Objective: The aim of this study was to investigate the association between conceptual metaphors of affect and physical dimensions. Background: The evidence that affect is unconsciously linked to physical dimensions(e.g., position and color) has been obtained in western cultures. However, in eastern cultures, especially, in Korea, it has been seldom tested. It is indispensable to examine whether or not cultural differences exist for better understanding of the conceptual metaphors. Method: 50 positive and 50 negative words were adopted from previous studies in order to determine the relationship between physical domains and abstract affect. Three hypotheses were tested in this study: (1) Good is up. (2) Good is bright. (3) Good is right(for right-handers). The automatic association between valence(positive vs. negative) and vertical position (up vs. down) was investigated in experiment 1, in which 100 words were randomly presented on either the top or the bottom of a LCD screen and the evaluation time of the presented word was recorded. The unconscious association between valence and color(white and black) was examined in experiment 2, where each word was randomly presented in either white or black. Lastly, we tested whether right-handers tend to associate rightward space with positive ideas and leftward space with negative ideas. Results: Reaction time was faster when words were presented in metaphor congruent domains(e.g., 'positive words on the top, in bright color, and on right space vs. negative words on the bottom, in dark color, and on left region) than when they were shown in metaphor incongruent domains. Conclusion: The results might give the groundwork for various directions in further understanding perception, emotion, and behavior. Application: This study may provide useful points to GUI designers and service developers if further studies enhanced in validity and reliability are followed.