• Communications of the Korean Mathematical Society
• /
• v.12 no.4
• /
• pp.975-984
• /
• 1997

In the Finsler space with an $(\alpha, \beta)$-metric, we can consider the difference tensors of the Finsler connection. The properties of the conformal transformation of these difference tensors are investigated in the present paper. Some conformal invariant tensors are formed in the Finsler space with an $(\alpha, \beta)$-metric related with the difference tensors.

• Kyungpook Mathematical Journal
• /
• v.56 no.1
• /
• pp.125-130
• /
• 2016

A finite rank difference of two composition operators is studied on a Hilbert Lebesgue space or a Hilbert Hardy space.

• Communications of the Korean Mathematical Society
• /
• v.25 no.2
• /
• pp.193-206
• /
• 2010

In this paper we define and study the difference Orlicz space of entire sequence of fuzzy numbers. We study their different properties and statistical convergence in these spaces.

• The korean journal of orthodontics
• /
• v.38 no.2
• /
• pp.74-82
• /
• 2008

Objective: This study examined the craniofacial morphology of young patients in their prepubertal stage showing class I, II malocclusion, by analyzing lateral cephalograms, and analyzed its relationship with tongue position, tongue space, and airway space in order to ascertain the effects of nasopharyngeal airway and tongue morphology on the form of the malocclusion. Methods: Seventy-six patients aging from 9 to 11 were divided into two groups depending on the ANB difference on the lateral cephalogram: Experimental group (CI II malocclusion group) showing $0{\le}ANB$ difference < 4.0; Control group (CI I malocclusion group) showing $0{\le}ANB$ difference < 4.0. The tongue space, space between palate and tongue, nasopharyngeal airway space and craniofacial morphology were compared between the two groups. Results: Tongue space, palate-tongue space, nasopharyngeal airway space showed no significant differences between class I and class II malocclusion groups. Hyperdivergent faces were associated with smaller nasopharyngeal airway space. Longer anterior facial height and posterior facial height were associated with larger tongue space, and greater anterior facial height were associated with lower tongue position. Smaller nasopharyngeal airway space showed smaller tongue space. Conclusions: Tongue space and nasopharyngeal airway space showed no significant differences between class I malocclusion group and class II malocclusion group. Only anterior facial height and posterior facial height had an influence on tongue space and nasopharyngeal airway space.

• Journal of Astronomy and Space Sciences
• /
• v.30 no.4
• /
• pp.315-320
• /
• 2013

Space geodetic techniques can be used to obtain precise shape and rotation information of the Earth. To achieve this, the representative combination solution of each space geodetic technique has to be produced, and then those solutions need to be combined. In this study, the representative combination solution of very long baseline interferometry (VLBI), which is one of the space geodetic techniques, was produced, and the variations in the position coordinate of each station during 7 years were analyzed. Products from five analysis centers of the International VLBI Service for Geodesy and Astrometry (IVS) were used as the input data, and Bernese 5.0, which is the global navigation satellite system (GNSS) data processing software, was used. The analysis of the coordinate time series for the 43 VLBI stations indicated that the latitude component error was about 15.6 mm, the longitude component error was about 37.7 mm, and the height component error was about 30.9 mm, with respect to the reference frame, International Terrestrial Reference Frame 2008 (ITRF2008). The velocity vector of the 42 stations excluding the YEBES station showed a magnitude difference of 7.3 mm/yr (30.2%) and a direction difference of $13.8^{\circ}$ (3.8%), with respect to ITRF2008. Among these, the 10 stations in Europe showed a magnitude difference of 7.8 mm/yr (30.3%) and a direction difference of $3.7^{\circ}$ (1.0%), while the 14 stations in North America showed a magnitude difference of 2.7 mm/yr (15.8%) and a direction difference of $10.3^{\circ}$ (2.9%).

• Journal of Astronomy and Space Sciences
• /
• v.27 no.4
• /
• pp.329-335
• /
• 2010

We investigate the sources of the variation of the high-latitude thermospheric neutral mass density depending on the interplanetary magnetic field (IMF) conditions. For this purpose, we have carried out the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) simulations for various IMF conditions under summer condition in the southern hemisphere. The NCAR-TIEGCM is combined with a new empirical model that provides a forcing to the thermosphere in high latitudes. The difference of the high-latitude thermospheric neutral mass density (subtraction of the values for zero IMF condition from the values for non-zero IMF conditions) shows a dependence on the IMF condition: For negative $B_y$ condition, there are significantly enhanced difference densities in the dusk sector and around midnight. Under the positive-$B_y$ condition, there is a decrease in the early morning hours including the dawn side poleward of $-70^{\circ}$. For negative $B_z$, the difference of the thermospheric densities shows a strong enhancement in the cusp region and around midnight, but decreases in the dawn sector. In the dusk sector, those values are relatively larger than those in the dawn sector. The density difference under positive-$B_z$ condition shows decreases generally. The density difference is more significant under negative-$B_z$ condition than under positive-$B_z$ condition. The dependence of the density difference on the IMF conditions in high latitudes, especially, in the dawn and dusk sectors can be explained by the effect of thermospheric winds that are associated with the ionospheric convection and vary following the direction of the IMF. In auroral and cusp regions, heating of thermosphere by ionospheric currents and/or auroral particle precipitation can be also the source of the dependence of the density difference on the IMF conditions.

• Journal of applied mathematics & informatics
• /
• v.25 no.1_2
• /
• pp.269-282
• /
• 2007

In this paper, we consider a two-dimensional fractional space-time diffusion equation (2DFSTDE) on a finite domain. We examine an implicit difference approximation to solve the 2DFSTDE. Stability and convergence of the method are discussed. Some numerical examples are presented to show the application of the present technique.

• Kyungpook Mathematical Journal
• /
• v.48 no.4
• /
• pp.613-622
• /
• 2008

In this article we introduce some difference sequence spaces defined by Orlicz function and study different properties of these spaces like completeness, solidity, symmetricity etc. We establish some inclusion results among them.

• Journal of applied mathematics & informatics
• /
• v.20 no.1_2
• /
• pp.535-540
• /
• 2006

In this paper, characterizations of difference quotient transformation in the Krein space which is contained continuously and contractively in the krein space of square summable power series C (z) is obtained from the complementation theory.

• Management Science and Financial Engineering
• /
• v.2 no.1
• /
• pp.147-176
• /
• 1996

The main objective of this study is to uncover the differences in the programming behavior between methodology creators and methodology users. We conducted an experiment with methodology creators who have invented one of the major object-oriented methodologies and with professional programmers who have used the same methodology for their software-development projects. In order to explain the difference between the two groups, we propose a theoretical framework that views programming as search in four problem spaces: representation, rule, instance and paradigm spaces. The main problem spaces in programming are the representation and rule spaces, while the paradigm and instance spaces are the supporting spaces. The results of the experiment showed that the methodology creators mostly adopted the paradigm space as their supporting space, while the methodology users chose the instance space as their supporting space. This difference in terms of the supporting space leads to different search behaviors in the main problem spaces, which in turn resulted in different final programs and performance.