• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.22.1-22.1
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• 2011

Two dominant components of polar motion are the Chandler and the annual components. Recently, the existence of 500-day period component in the Earth's polar motion has been manifested. But its existence is not clear on Fourier spectrum. One cause of difficulty involved here is that the amplitudes of the two main components are slightly variable in time by certain amounts (Chandler: 0.15~0.28 arcsec, annual: 0.09~0.15 arcsec). A residual polar motion time series excluding the two main components for a time span between 1962 Jan and 2010 Nov from IERS C04 time series dataset was constructed by least square fitting. For faithful fitting, 43 time segments of 6.8 year length (each starts on January 1st of successive years) were separately acquired and later combined together. The period of dominant peak in the spectrum of this residual polar motion time series is 490 days. Next peaks have their periods as semi-annual, 300~330 days, ~560 days, 670 days, and 1360 days.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.39-46
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• 2006

This paper analyzes the continuous Galerkin method for the space-time discretization of wave equation. The method of space-time finite elements enables the simple solution than the usual finite element analysis with discretization in space only. We present a discretization technique in which finite element approximations are used in time and space simultaneously for a relatively large time period called a time slab. The weighted residual process is used to formulate a finite element method for a space-time domain. Instability is caused by a too large time step in successive time steps. A stability problem is described and some investigations for chosen types of rectangular space-time finite elements are carried out. Some numerical examples prove the efficiency of the described method under determined limitations.

• Journal of Korean Philosophical Society
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• v.144
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• pp.235-256
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• 2017

This essay considers Leibniz-Clark correspondence on the nature of space and hole argument. The ontology of space had been debated under the name of substantivalism-relationism controversy. The debates between the two parties are concerned with the nature of existence of parts of space-time. Substantivalism claims that the point of space-time has existence analogous to that of material substance. Relationism argues that space-time should be understood as the framework of possible spatio-temporal relations between bodies. Although these two approaches attempt to respect theoretical context, it seems that the problems of these two interpretive schemes stems from the lack of understanding of the structure of space-time theories, especially how space-time is connected with the laws of motion. In order to appreciate the substance-relation controversy without deviating from the context of space-time theories, it is necessary then to capture how space-time theories are constituted. This essay offers the clear connection of ontology of space-time with present practices of theoretical physicists.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.339-350
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• 2005

A space-time fractional advection-dispersion equation (ADE) is a generalization of the classical ADE in which the first-order time derivative is replaced with Caputo derivative of order $\alpha{\in}(0,1]$, and the second-order space derivative is replaced with a Riesz-Feller derivative of order $\beta{\in}0,2]$. We derive the solution of its Cauchy problem in terms of the Green functions and the representations of the Green function by applying its Fourier-Laplace transforms. The Green function also can be interpreted as a spatial probability density function (pdf) evolving in time. We do the same on another kind of space-time fractional advection-dispersion equation whose space and time derivatives both replacing with Caputo derivatives.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.168-177
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• 2019

In cinema, a montage can be defined as temporalization. In reverse, it is evident that this method results in the spatialization of time. In movies, you are free to go to the past or future, see separated times together, and separate the same time into different ones. Therefore, in one aspect, time is turned into space, and on the other hand, space is turned into time. In conclusion, space in cinema inevitably expresses time. The movie the creative arrangement of time and space played a big role in making a movie that simply overlaps a story from high school to the present attract over seven million audiences. Director Kang Hyung-cheol used his unique film production language to transform boring into cheerfulness and stale to delight, and he helped the audience heal their wounds from their youth. He said, "The most important aspect of movie production is creating visual stories, and the background of such visual story is time and space." This paper aims at analyzing the creative time and space production of the director in the film .

• Communications of the Korean Mathematical Society
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• v.33 no.1
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• pp.305-315
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• 2018

This note provides a study of lightlike hypersurfaces of a generalized Robertson-Walker(GRW) space-time with a certain screen distribution, which are integrable and have good properties. Focus is to investigate geometric features from the relation of the second fundamental forms between lightlike hypersurfaces and leaves of the integrable screen distribution. Also, we shall apply those results on lightlike hypersurfaces of a GRW space-time to lightlike hypersurfaces of a Robertson-Walker(RW) space-time.

• Journal of Family Resource Management and Policy Review
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• v.9 no.4
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• pp.21-40
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• 2005

The purpose of this study was to exam the activities by the distribution of time and space occupancy on their weekday and weekend. to study the space and labor segregation by sex. The sample population included 23 wives and their husbands(30-40 years old). The major findings of the research are as follows: First, it shows that wives' time use by activity was consistent with the space occupancy on weekday. Second, on weekend, wives was used to stay in living room most of time. Thirdly, husbands show the stereotype of time use on weekday, and substitute leisure time for labor time. Finally, on weekend, the wives and husbands have the joint time in the household labor or leisure activities.

• Bulletin of the Korean Mathematical Society
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• v.25 no.2
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• pp.195-201
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• 1988

In general relativity, analyzing causality is central to the study of black holes, to cosmology, and to each of the major recent mathematical theorems. By causality we refer to the general question of which points in a space-time can be joined by causal curves; relativistically which events can influence (be influenced by) a given event. Various causality conditions have been developed for space-times of the problems associated with examples of causality violations (2, 4). Causally continuous space-times were defined by Hawking and Sachs (5). Budic and Sachs (3) established causal completion. A metrizable topology on the causal completion of a causally continuous space-time was studied by Beem(1). Recently the region of space-time where causal continuity is violated was studied by Ishikawa (6) and Vyas and Akolia (8). In this paper we show characterization for reflectingness in terms of continuity of set valued functions. We investigate some properties of the region related to a causally continuous space-time where distinguishingness is violated, and characterize the chronology condition in terms of distinguishing-violated region.

• Korean Institute of Interior Design Journal
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• v.22 no.1
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• pp.154-163
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• 2013

This study is aimed to identify the expression and the sense of time in contemporary architectural space. And to classify the system and elements of Zeitlichkeit in the contemporary architectural design. The concept of time can be divided into two meaningful perceptions. Those are the concept of realistic time and the concept of subjective time. These tendencies of theories of architectural space has borrowed from innovations in the sciences, and the whole idea of space-time within art and architecture. Those notions developed through the researches of Bauhaus, Postmodernism, Landscape architecture, Digital Architecture and so forth. The result of this study is that the concepts of time are one of the most important strategies of architectural design and have the various languages which there was not in the past. At the point of the transformation in contemporary architecture, the The concepts of space-time are classified into those from the orders of form and space, from dynamic of the image in the dissolution of architectural form, from traces and steps of movement in dynamic form, and from the systems of commands in the digital softwares. As such, Zeitlichkeit in contemporary architecture means that the architecture moves from the construction of the sensual design elements into Art of life through events and contents which human can experience and recognize. These theories and researches reveal that contemporary architectural movements insert the meaningful stories into architectural space through programs and diagrams.

• Journal of Korea Planning Association
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• v.53 no.7
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• pp.23-37
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• 2018

In recent years, there has been a proliferation of commercial uses in the area where Gentrification occurs. In order to cope with such a diffusion phenomenon, it is necessary to derive the diffusion area accurately. Gentrification has a feature that occurs locally in a short time. Therefore, this study used the space-time pattern analysis to derive the diffusion area of commercial uses in Bukchon, a typical gentrified area in Seoul. Among the space-time pattern analysis, space time permutation statistics used in this study can derive the convergence phenomenon of time and space in a particular case with only the location information. The results confirmed that there has been three proliferation area in Bukchon, one started in 2007, other in 2013 and the other in 2014. In the earliest area, independent shops were the most popular, and the majority of them were restaurants. However in latter areas, there has been more chain stores and clothing stores than earlier area. The findings of this study indicate that space time pattern analysis can be used as a tool to analyze the proliferation by gentrification because it can derive accurate location and timing of the diffusion.