• Journal of Korea Multimedia Society
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• v.10 no.8
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• pp.1068-1077
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• 2007

This paper proposes a method that extracts characteristics of cracks such as length, thickness and direction from a concrete slab surface image with image processing techniques. These techniques extract the cracks from the concrete surface image in variable conditions including bad image conditions) using the ART2-based RBF network to recognize the dominant directions -45 degree, 45 degree, horizontal and vertical) of the extracted cracks from the automatically calculated specifications like the lengths, directions and widths of the cracks. Our proposed extraction algorithms and analysis of the concrete cracks used a Robert operation to emphasize the cracks, and a Multiple operation to increase the difference in brightness between the cracks and background. After these treatments, the cracks can be extracted from the image by using an iterated binarization technique. Noise reduction techniques are used three separate times on this binarized image, and the specifications of the cracks are extracted form this noiseless image. The dominant directions can be recognized by using the ART2-based RBF network. In this method, the ART2 is used between the input layer and the middle layer to learn, and the Delta learning method is used between the middle layer and the output layer. The experiments using real concrete images showed that the cracks were effectively extracted, and the Proposed ART2-based RBF network effectively recognized the directions of the extracted cracks.

• The Korean Journal of Archival Studies
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• no.17
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• pp.115-156
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• 2008

Archival objects produced in relation to the activities of public institutions hold the inexpressible symbolism, historical value, and esthetical value as well in that the values of display and reuse of archives materials in the future are high as figures. The revised law of Archives Act in 2007 has provided a foundation for managing the archival objects in every public organization, by also including archival objects into the category of archives produced and registered in relation to their works. Although it could be seen as a reforming will to aim at the differential approach from the past to recognize the archival objects as records and make the managing will documented, it is still in an unprepared state to define the concepts on archival objects and to have methods to systematically manage and preserve them. Thus this paper has researched on the type classification of archival objects and their evaluation, as way of developing the methods for the management system for archival objects. On the premise that it should be preceded by clear definitions of concepts and distinctive understanding of their types first in order to build up the management system for archival objects, definition and type classification of the archival object have been attempted, based on the actual research materials and the current relevant laws. In addition, this study has analyzed the characteristics of selecting archival objects in order to search for which one they should obtain and manage among archival objects produced and reused in relation to the works of public institutions. On the basis of this, the plans for the national selection system and provision of selecting criteria for the subjects of permanent preservation have been suggested in this study.

• Smart Media Journal
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• v.10 no.3
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• pp.23-30
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• 2021

Although the manufacturing time series data clustering technique is an important grouping solution in the field of detecting and improving manufacturing large data-based equipment and process defects, it has a disadvantage of low accuracy when applying the existing static data target clustering technique to time series data. In this paper, an evolutionary computation-based time series cluster analysis approach is presented to improve the coherence of existing clustering techniques. To this end, first, the image shape resulting from the manufacturing process is converted into one-dimensional time series data using linear scanning, and the optimal sub-clusters for hierarchical cluster analysis and split cluster analysis are derived based on the Pearson distance metric as the target of the transformation data. Finally, by using a genetic algorithm, an optimal cluster combination with minimal similarity is derived for the two cluster analysis results. And the performance superiority of the proposed clustering is verified by comparing the performance with the existing clustering technique for the actual manufacturing process image.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.4
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• pp.443-453
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• 2013

This study aims to evaluate the mechanical behaviors of unsupported rock pillars in a room-and-pillar underground structure by a series of numerical analyses. In addition, rock pillar strengths estimated by a few empirical equations proposed for underground mines are compared with those from numerical analyses. Based on the results from the numerical analysis, the ratio of pillar strength to rock mass strength increases as the ratio of the width of a pillar to its height becomes bigger. It means that higher ratio of pillar width to its height is much more favorable for stabilizing a room-and-pillar underground structure. Especially, unsupported pillar strengths estimated from numerical analyses are higher than rock mass strength when the ratio of pillar width to height is approximately over 1.5. It is also found that the choice of an empirical equation appropriate for a given geometric condition of a pillar is important for its feasible application to the stability analysis of a pillar in the room-and-pillar method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1383-1389
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• 2011

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.1-10
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• 2005

This paper presents a technique for localization of a mobile robot using a single ultrasonic sensor. The mobile robot is designed for operating in a well-structured environment that can be represented by planes, edges, corners and cylinders in the view of structural features. In the case of ultrasonic sensors, these features have the range information in the form of the arc of a circle that is generally named as RCD (Region of Constant Depth). Localization is the continual provision of a knowledge of position which is deduced from it's a priori position estimation. The environment of a robot is modeled into a two dimensional grid map. we defines a physically-based sonar sensor model and employs an extended Kalman filter to estimate position of the robot. The performance and simplicity of the approach is demonstrated with the results produced by sets of experiments using a mobile robot.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.57-65
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• 2006

This paper presents hybrid structural damage monitoring system which performs both global damage assessment of structure and damage detection of local structural joints. Hybrid damage monitoring system is composed of vibration-based technique and electro/mechanic impedance technique. Vibration-based technique detects global characteristic change ot structure using modal characteristic change of structure, and electro/mechanical impedance technique detects damage existence of local structural joints using impedance change of PZT sensor. For the verification of the proposed hybrid monitoring system, a series of damage scenarios are designed to loosened bolts situations of the structural joints, and acceleration response and impedance response signatures are measured. The proposed hybrid monitoring system is implemented to monitor global damage-state and local damages in structural joints.

• Journal of the Korea Society of Computer and Information
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• v.24 no.10
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• pp.11-23
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• 2019

This paper designs and proposes a file conversion process to IFC file, the international standard file format for BIM, in order to ensure mutual compatability and manageability among users of commercial BIM modeling and design softwares in the civil engineering area. The proposed process insert additional properties consisting of the properties of quantity calculation codes and properties of CBS/OBS/WBS standard classification scheme, to the three dimensional object shape information of the converted IFC files, using add-in converters for commercial BIM modeling softwares. In addition, a process of integrated use of IFC files for open web-based quantity, process(4D), and construction cost(5D) management is additionally designed and implemented. Based on these works, the ultimate goal of this study is to propose a novel process for integrated use of open web-based quantity, process(4D), and construction cost(5D), from the design stage of BIM modeling to the final construction stage in the civil engineering area.

• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.115-126
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• 2016

This paper suggests the method of the spherical signature description of 3D point clouds taken from the laser range scanner on the ground vehicle. Based on the spherical signature description of each point, the extractor of significant environmental features is learned by the Deep Belief Nets for the urban structure classification. Arbitrary point among the 3D point cloud can represents its signature in its sky surface by using several neighborhood points. The unit spherical surface centered on that point can be considered to accumulate the evidence of each angular tessellation. According to a kind of point area such as wall, ground, tree, car, and so on, the results of spherical signature description look so different each other. These data can be applied into the Deep Belief Nets, which is one of the Deep Neural Networks, for learning the environmental feature extractor. With this learned feature extractor, 3D points can be classified due to its urban structures well. Experimental results prove that the proposed method based on the spherical signature description and the Deep Belief Nets is suitable for the mobile robots in terms of the classification accuracy.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.479-489
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• 2015

The paradigm of communication is changing by the generalization of mobile computers and the extension of network service. In the mobile messenger communication, people are increasingly using character emoticons to substitute linear text. This means that the character emoticons are functioning as narrative characters so that they are becoming the nonlinear techno-code, which can substitute for the alphabet code. As Vil$\acute{e}$m Flusser said, the post-modern communication is arrived. In this kind of communication, storytelling with character emoticons are effective enough to tell various stories. In this point of view, this paper tries to prove the functions of character emoticons and suggests the classification of the character emoticon series. This paper also structures the post-modern communication model as a new paradigm of visual communication.