• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.121-127
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• 2011

Spatial distribution of void space in concrete materials strongly affects mechanical and physical behaviors. Therefore, the identification of characteristic void distribution helps understand material properties and is essential to estimate the integrity of material performance. The 3D micro CT (X-ray microtomography) is implemented to examine and to quantify the void distribution of a lightweight aggregate concrete using an image analysis technique and probabilistic approach in this study. The binarization and subsequent stacking of 2D cross-sectional images virtually create 3D images of targeting void space. Then, probability distribution functions such as two-point correlation and lineal-path functions are applied for void characterization. The lightweight aggregates embedded within the concrete are individually analyzed to construct the intra-void space. Results shows that the low-order probability functions and the density distribution based on the 3D micro CT images are applicable and useful methodology to characterize spatial distribution of void space and constituents in concrete.

• Spatial Information Research
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• v.8 no.2
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• pp.301-315
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• 2000

Every, year, a great amount of site investigation data is collected on site to obtain sufficient conditions. Investigation of subsurface conditions is prerequisite to the design and construction of structures and also provides information on ground properties such as geologic formation and types of soil. This data set, which portrays real representation of ground conditions over the existing geologic and soil maps, could be further utilized for analyzing the subsurface conditions. It is therefore necessary to develope a subsurface exploration analysis system which is able to extract the valuable information from the heterogeneous, non-normalized subsurface investigation data. This paper presents the overall design scheme and implementation on a subsurface exploration analysis system. The analysis system employs one of data set such as bore-hole data. The clustering technique employed in the developed system makes a large volume of bore-hole data into several groups in terms of ground formation and geographical vicinity. As a result of clustering, each group or cluster consists of bore-hole data with similar characteristics of subsurface and geographical vicinity. In addition, each clustered data is displayed on digital topographical map with different color so that the analysis of site investigation data could be performed in more sensible ways.

• Structural Engineering and Mechanics
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• v.65 no.5
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• pp.573-585
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• 2018

This article presents strain gradient elasticity-based procedures for static bending, free vibration and buckling analyses of functionally graded rectangular micro-plates. The developed method allows consideration of smooth spatial variations of length scale parameters of strain gradient elasticity. Governing partial differential equations and boundary conditions are derived by following the variational approach and applying Hamilton's principle. Displacement field is expressed in a unified way to produce numerical results in accordance with Kirchhoff, Mindlin, and third order shear deformation theories. All material properties, including the length scale parameters, are assumed to be functions of the plate thickness coordinate in the derivations. Developed equations are solved numerically by means of differential quadrature method. Proposed procedures are verified through comparisons made to the results available in the literature for certain limiting cases. Further numerical results are provided to illustrate the effects of material and geometric parameters on bending, free vibrations, and buckling. The results generated by Kirchhoff and third order shear deformation theories are in very good agreement, whereas Mindlin plate theory slightly overestimates static deflection and underestimates natural frequency. A rise in the length scale parameter ratio, which identifies the degree of spatial variations, leads to a drop in dimensionless maximum deflection, and increases in dimensionless vibration frequency and buckling load. Size effect is shown to play a more significant role as the plate thickness becomes smaller compared to the length scale parameter. Numerical results indicate that consideration of length scale parameter variation is required for accurate modelling of graded rectangular micro-plates.

• Spatial Information Research
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• v.23 no.1
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• pp.49-57
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• 2015

Due to high density of population and progress of high building construction technologies, the number of high buildings has been increasing. Several information services have been provided to figure out complex indoor structures of building such as indoor navigations and indoor map services. The most fundamental information for these services are indoor network information. Indoor network in building provides topological connectivity between spaces unlike geometric information of buildings. In order to make indoor network information, we have to edit network manually or derive network properties based on the geometric data of buildings. This process is not easy for complex buildings. In this paper, we suggest a method to generate indoor network automatically based on crowdsourcing. From the collected individual trajectories, we derive indoor network information with crowdsourcing. We validate our method with a sample set of trajectory data and the result shows that our method is practical if the indoor positioning technology is reasonably accurate.

• The Journal of the Korea Contents Association
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• v.6 no.11
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• pp.202-216
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• 2006

A number of process algebras are not well suitable for real-time navigation/delivery systems due to the following reasons: 1) lack of representation of process distributivity over some geographical space and 2) the indistinction of representation of process mobility from process distributivity over the space. To make the process algebra suitable to the systems, it seems to be necessary to separate the space representation from the mobility representation. This paper presents a formal method for this purpose, namely, Calculus of Abstract Real-Time Distribution, Mobility, and Interaction (CARDMI). For analysis and verification of behavioral properties, CARDMI defines a set of the spatial, temporal and the interactive deduction rules and a set of equivalence relations. The rules and equivalences can be abstracted hierarchically due to the spatial abstraction, too. CARDMI can be applied to virtual navigation/delivery system for contents, too.

• The KIPS Transactions:PartB
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• v.11B no.1
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• pp.21-26
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• 2004

Color image quantization is a process of selecting a set of colors to display an image with some representative colors without noticeable perceived difference. It is very important in many applications to display a true color image in a low cost color monitor or printer. The basic problem is how to display 256 colors or less colors, called color palette, In this paper, we propose improved binary tree vector quantization based on spatial sensitivity which is one of the human visual properties. We combine the weights based on the responsibility of human visual system according to changes of three Primary colors in blocks of images with the process of splitting nodes using eigenvector in binary tree vector quantization. The test results show that the proposed method generates the quantized images with fine color and performs better than the conventional method in terms of clustering the similar regions. Also the proposed method can get the better result in subjective quality test and WSNR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1843-1850
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• 2004

If the location information of a great number of cars kept for business with telematics terminals is acquired and managed efficiently, this information forms the foundation for controlling cars and traffic flows. The studies on the pure spatial indices have focused on the efficient retrievals. However, the acquisition and management of the terminal location of moving objects are more important than the efficiency of the query processing in the moving object databases. Therefore, it will be need to adopt parallel processing system for the moving object databases which should maintain the object's current location as precise as possible. This paper proposes a location management system using CDMA communications of telematics terminals. More precisely, we propose a architecture of spatial indexing mobile objects using multiple processors, and also newly propose a method of splitting buckets using the properties of moving objects in order to minimize the number of database updates. We also propose a acquisition method for gathering the location information of moving objects and passing the information of the bucket extents in order to reduce the amount of passed messages between processors.

• Journal of the Korean Society of Combustion
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• v.2 no.1
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• pp.17-27
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• 1997

It is well known that NOx formation has a strong dependence on the maximum temperature and correspondingly with the maximum chamber pressure of a closed combustion system. However, in a case of impinging-jet-flame (IJF hereafter) combustion with opposed dual pre-chambers, low $NO_x$ formation with high pressure could be achieved, but its mechanism has not been clearly understood so far. In this study, a three-dimensional analysis is adopted to resolve time-variant local properties that might indicate the mechanism of IJF combustion. Numerical results are verified by comparing them with experiments. The IJF combustion in a vessel with no pre-chamber, with single pre-chamber, and with dual pre-chambers is studied. The orifice diameter and the volumetric ratio of pre-chamber are used as geometric parameters. The effects of main-chamber ignition delay time and combustion time of main-chamber, orifice exit velocity, orifice exit temperature, turbulent kinetic energy of main-chamber and spatial distribution of temperature in the latter stage of combustion are investigated. A longer main-chamber ignition delay and a shorter main-chamber combustion time suppress the formation of high temperature region with respect to mean temperature, which consequently results in less NO production.

• Korean Journal of Cognitive Science
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• v.20 no.4
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• pp.439-479
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• 2009

This paper examines the aspects of the inferences between the dimensional terms in Korean, and attempts to give an account of the inference patterns based on the interaction of gestalt and position properties of spatial objects. Following Lang (1987) and Lang, Carstensen & Simmons (1991), we advance the idea that the inferences are possible for the same axis of a spatial object, if some contextually induced positional specifications are reversed to the inherent proportion schema. Two simple inference rules are proposed and justified. They are applied under the assumption that the inferences of the dimensional terms are drawn in a unidirectional way, i.e, from the Primary Perceptional Space to the Inherent Proportional Schema.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6906-6914
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• 2014

This study examined the remodeling characteristics of traditional urban housing for lease focusing on Hanok in the traditional urban housing neighborhood of Bukchon. Furthermore, the space syntax was used as the main analytic approach to objectively revealing the change in social properties of each spatial element because each room forms its status in the structural relation with many rooms and accommodates the special change in traditional housing and modern life. These findings revealed the following; spatial division between the landlord and tenant results in a hierarchical change in the yard and main hall and strengthens the privacy of the space of the landlord.