• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.53.1-53.1
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• 2021

Dwarf galaxies are the most abundant objects in the universe. Hence, understanding the dwarfs is important but relatively little is known due to the lack of computing power and limitations in the telescope resolution. We thus use the state-of-the-art NewHorizon simulation, which is a set of cosmological hydrodynamical simulations, to dissect the quenching mechanism working on dwarf galaxies by inspecting the star formation and mass history of individual galaxies. It is known that internal (AGN, SN, stellar feedback) and external (major and minor mergers, ram pressure stripping, strangulation) mechanisms affect the quenching of dwarfs. Because of the combination of these mechanisms, periodicity in the star formation history of the dwarf galaxies is expected. To check for their periodicity, Fourier transform was performed on the star formation history. By comparing the physical timescales and the periodicity, we determine the dominant effect working on the dwarfs. Then, we compare the dominant effects working on the galaxies according to their varying properties.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.57-62
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• 2024

This study conducted a measurement method of high temeprature conditions using infrared termography. All objects emit infrared light, and this emissivity has a significant impact on the temperature measurements of infrared thermal imaging (IR) cameras. In order to measure the temperature more accurately with the IR camera, correction equations were derived by measuring the emissivity according to the temperature change of combustible metals in a high-temperature environment. Two combustible metals, Mg and Al, were used to measure emissivity with changing temperature. Each metal was heated, the emissivity was measured by comparing the temperature with IR camera and thermocouples so that the correlation between temperature and emissivity could be anslyzed. As a result of the experiment, the emissivity of the metals increases as the temperature increased. This can be interpreted as a result of increased radiation emission as the thermal movement of internal metal molecules increased.

• Physical Therapy Korea
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• v.27 no.1
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• pp.38-44
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• 2020

Background: Posterior shoulder tightness, which is a problem mainly seen in patients with shoulder impingement syndrome, disrupts the scapulohumeral rhythm between the humerus and scapulae. Objects: The aim of this study was to compare the effects of joint mobilization and stretching on shoulder muscle activity and internal rotation range of motion (ROM) of the glenohumeral joint in patients with impingement syndrome with posterior shoulder tightness. Methods: The research subjects included 22 in-patients with impingement syndrome with posterior shoulder tightness. They were randomly divided into two groups: one group (12 patients) was treated with joint mobilization and the other group (10 patients) was treated with stretching for the posterior shoulder tightness. Each treatment was performed five times a week for two weeks, and there were 15 sessions for each treatment. The ROM of the internal rotation and muscle activities of shoulder joint were evaluated pretest and posttest in each group. Electromyography data were collected from the upper, middle, and lower trapezius and serratus anterior during shoulder abduction of 90°, 120°, and 150°. Results: Both the joint mobilization and stretching groups showed significant decreases in muscle activity in the upper, middle, and lower trapezius on the posttest (p < 0.05). There was a significant difference in serratus anterior at 150° (p < 0.05), but there was no significant difference between group in post-hoc analysis (p > 0.025). The internal rotation ROM was significantly increased in the stretching group compared to that in the joint mobilization group (p < 0.025). Conclusion: This study found that both joint mobilization and stretching for posterior shoulder tightness were effective in muscle activity during arm abduction, also in order to increase internal rotation ROM of shoulder joint, stretching was effective in patients with impingement syndrome with posterior tightness.

• Journal of the Korea Computer Graphics Society
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• v.6 no.1
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• pp.19-27
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• 2000

This paper proposes a non-self-intersecting multiresolution deformable model to extract and reconstruct three-dimensional boundaries of objects from volumetric data. Deformable models offer an attractive method for extracting and reconstructing the boundary surfaces. However, convensional deformable models have three limitations- sensitivity to model initialization, difficulties in dealing with severe object concavities, and model self-intersections. We address the initialization problem by multiresolution model representation, which progressively refines the deformable model based on multiresolution volumetric data in order to extract the boundaries of the objects in a coarse-to-fine fashion. The concavity problem is addressed by mesh size regularization, which matches its size to the unit voxel of the volumetric data. We solve the model self-intersection problem by including a non-self-intersecting force among the customary internal and external forces in the physics-based formulation. This paper presents results of applying our new deformable model to extracting a sphere surface with concavities from a computer-generated volume data and a brain cortical surface from a MR volume data.

• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.157-164
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• 2001

This paper studies on the processing of spatial joins. The spatial join operation is divided into filters and refinement steps in general. The processing of spatial joins can be greatly improved by the use of filters that reduce the polygons in order to find the intersecting ones. As a result, three possible sets of answers are identified: the positive one, the negative one and the inconclusive one. To identify all the interesting pairs of polygons with inconclusive answers, it is necessary to have access to the representation of polygons so that an exact geometry test can take place. We introduce a bit-map approximation technique to drastically reduce the computation required by the refinement step during refinement processing. Bit-map representation are used for the description of the internal, the external and the boundary regions of the polygon objects. The proposed scheme increases the chance of trivial acceptance and rejection of data objects, and reduces unnecessary disk accesses in query processing. It has been shown that the reference to the object data file can be cut down by as much as 60%.

• Journal of the Korean Society of Costume
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• v.63 no.1
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• pp.97-107
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• 2013

To give satisfaction with the fit to a wearer, the wearer's body size and body types should be considered first, this study conducted the descriptive statistical analysis on the upper body measurements of women in their 20s because their body shape has reached the completion stage of adult female's physical development. Also, the analysis classified their upper body types into groups to secure basic data for (maximum satisfaction with the fit of ready-to-wear clothing. The factor analysis was conducted using 49 items of measurement. The main factor analysis was used as a factor extraction method. After extracting the factors with Eigenevalues over 1, the factor loadings were drawn using the Varimax rotation. As a result, 6 factors were extracted. To secure internal consistency, factors that could lower the reliability of the experiment were taken out, so only 36 of the 49 items were used for the analysis. After selecting the items to recognize the main features of each body type, they were used for the final factor analysis. The entire R square of the 6 factors was 84.06%. To classify the upper body types of women in their 20s and to recognize the main features of each body shape type, the researcher conducted the cluster analysis with the items generated from the factor analysis. Through the cluster analysis, the upper body type of women in their 20s were classified into 3 body types. Also, since there are some restrictions on this research objects in terms of local and numbers of measured objects, the results of the this research should only be used as basic data.

• Journal of Digital Convergence
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• v.18 no.4
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• pp.439-451
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• 2020

In order to deeply understand the significance of death aesthetics in contemporary art, this research first summarizes the development process of death aesthetics in art works with popular perspectives, and then classifies and discusses death aesthetics in modern art works. The results of this study are as follows: First, the aesthetic expressions of death are divided into two types: death reproducibility and death symbolism. Death reproducibility includes reproducibility of real objects and reproducibility of imaginary objects. The symbolism of death can be divided into external and internal manifestations. Secondly, in contemporary art, the reproducibility of death through the description of death scenes has increased the various problems and philosophical significance caused by death. Third, in contemporary art, the symbolism meaning of death is not just something directly related to death, it also shows the various psychological states brought about by death. Subsequent research will promote the artists' visual expression of the aesthetics of death in artworks, and the profound changes in meaning that result from it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.580-585
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• 2009

Real Time Locating Systems (RTLS) are used to track and identify the location of objects in real time using simple, inexpensive tags attached to or embedded in objects and readers that receive the wireless signals from these tags to determine their locations. A tag is powered an internal source such as a battery. The blink frequency of a tag affects the energy efficiency and the locating accuracy of RTLS. The mobility of a tag also affects the locating accuracy. In this paper, we introduce a RTLS tag design which improves the locating accuracy and the power efficiency. We propose an adaptive transmission-rate control algorithm using a motion sensor. By analyzing the signal pattern of the motion sensor, we can build a model to estimate the speed of the motion. Using this model, our algorithm can achieve better locating accuracy and lower power consumption than those of the conventional method. In our experiments, the number of transmission reduced as 40%, keeping similar locating accuracy.

• The Research Journal of the Costume Culture
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• v.30 no.2
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• pp.262-280
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• 2022

The purpose of this study is to analyze the organic forms, expressions, and characteristics of Alexander McQueen's fashion design and to present various materials for understanding and utilizing this organic design style. The criteria for organic design expressions and characteristics were classified through a literature review, and the organic design characteristics of Alexander McQueen's fashion were then analyzed. The results are as follows: First, the morphological characteristics of nature's forms are used as objects in Alexander McQueen's fashions to represent organic characteristics. Second, abstraction through the application of organic forms means creating an abstract representation of the object being represented. Abstracting organic forms occurs by partially modifying the structural features of the human body to show characteristics or by visualizing these characteristics within the surface of the natural object. Third, continuity through the expression of the formation process of organisms is characteristic of the expression of the gradual growth of organisms; this reinterpretation is based on the concept that the internal elements of natural objects affect their external forms. Fourth, the structure of using natural materials, as well as regional and cultural characteristics, is shown in the designs through use of the physical characteristics of expressions and materials that use natural elements. Fifth, symbolism through subjective thinking implies that the element of nature that an object expresses is the element that appears in nature; this includes created organisms along with environmental factors. These characteristics are best demonstrated in fashion designs that express themselves through creativity.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.171-178
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• 2014

This paper presents dynamic modelling of a virtual object in augmented reality environments when external forces are applied to the object in real-time fashion. In order to simulate a natural behavior of the object we employ the theory of Newtonian physics to construct motion equation of the object according to the varying external forces applied to the AR object. In dynamic modelling process, the physical interaction is taken placed between the augmented object and the physical object such as a haptic input device and the external forces are transferred to the object. The intrinsic properties of the augmented object are either rigid or elastically deformable (non-rigid) model. In case of the rigid object, the dynamic motion of the object is simulated when the augmented object is collided with by the haptic stick by considering linear momentum or angular momentum. In the case of the non-rigid object, the physics-based simulation approach is adopted since the elastically deformable models respond in a natural way to the external or internal forces and constraints. Depending on the characteristics of force caused by a user through a haptic interface and model's intrinsic properties, the virtual elastic object in AR is deformed naturally. In the simulation, we exploit standard mass-spring damper differential equation so called Newton's second law of motion to model deformable objects. From the experiments, we can successfully visualize the behavior of a virtual objects in AR based on the theorem of physics when the haptic device interact with the rigid or non-rigid virtual object.