• Journal of Korea Multimedia Society
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• v.14 no.5
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• pp.691-702
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• 2011

Recently, several researchers have attempted to combine human visual perception and computer graphics. Cole et. al. suggest the study results in which line drawing algorithm in computer graphics characterize the properties of line drawing made by artists. The paper also evaluates CG line drawing algorithms depending on whether people recognize effectively specific 3D shape from the image made by those CG line drawing algorithms. However, human recognizes the shape of objects more effectively in image made by BRDF shading model than line drawing algorithm. It means that the shading factor is important to recognize shape with human perception. In this paper, we analyze the correlation between shading made by human artists and that made by CG shading algorithms. The study is to characterize the mathematical properties of artists' shading and CG shading. This type of analysis can guide the future development of new CG shading algorithm in computer graphics for the purpose of shape perception.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.402-410
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• 2020

Purpose: The purpose of this research is to eliminate communication shadowing loss of the 'smart safety management system'. The 'smart safety management system' can monitor and relay real time data of workers working in high risk workplace (i.e: industrial scene, disaster scene). The data will provide the rescue team the 'golden hour' in their rescue operations. Method: In this research, safety tag was designed and implemented so that it acts as a repeater for the user. Result: In other words, when communication in-between the safety tag and headquarters' communication terminal is jeopardized, the safety tag will act as a repeater-terminal for other safety tags in the area. Conclusion: The research tested if a specific building with communication shadowing loss problem was resolved when safety tags were implemented. Communication shadowing was first identified in-between the safety tag and headquarters' communication terminal. When extra safety tags were deployed in the same situation, the results showed that the communication shadowing loss was resolved. The repeater safety tags could resolve communication shadowing loss of up to three basement levels in this test building.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.173-188
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• 2024

With the advancement of autonomous vehicle (AV) technology, autonomous driving on real roads has become feasible. However, there are challenges in achieving complete autonomy due to perceptual blind areas, which occur when the AV's sensory range or capabilities are limited or impaired by surrounding objects or environmental factors. This study aims to analyze AV accident patterns and safety issues of perceptual blind area that may occur in urban areas, with the goal of developing test scenarios for Level 4+ autonomous driving. It utilized AV accident data from the California Department of Motor Vehicles (DMV) to compare accident patterns and characteristics between AVs and conventional vehicles based on activation status of autonomous mode. It also categorized AV disengagement data to identify types and real-world cases of disengagements caused by perceptual blind areas. The analysis revealed that AVs exhibit different accident types due to their safe driving maneuvers, and three types of perceptual blind area scenarios were identified. The findings of this study serve as crucial foundational data for developing Level 4+ autonomous driving test scenarios, enabling the design of efficient strategies to mitigate perceptual blind areas in various scenarios. This, in turn, is expected to contribute to the effective evaluation and enhancement of AV driving safety on real roads.

• Journal of the Korea Computer Graphics Society
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• v.24 no.5
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• pp.31-39
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• 2018

In this paper, we propose an automated method for the ground-glass nodule(GGN) classification using GGN-Net based on intensity, texture, and shape-enhanced images in chest CT images. First, we propose the utilization of image that enhances the intensity, texture, and shape information so that the input image includes the presence and size information of the solid component in GGN. Second, we propose GGN-Net which integrates and trains feature maps obtained from various input images through multiple convolution modules on the internal network. To evaluate the classification accuracy of the proposed method, we used 90 pure GGNs, 38 part-solid GGNs less than 5mm with solid component, and 23 part-solid GGNs larger than 5mm with solid component. To evaluate the effect of input image, various input image set is composed and classification results were compared. The results showed that the proposed method using the composition of intensity, texture and shape-enhanced images showed the best result with 82.75% accuracy.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.75-91
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• 2023

In this study, we explore the use of ground penetrating radar (GPR) for the nondestructive survey of subsurface conduits, focusing on the challenges posed by multichannel environments. A key concern is the shadow regions created by conduits, which significantly impact survey results. The shadow regions, which are influenced by conduit position and diameter, hinder signal propagation, thereby making detection within these regions challenging. Using finite-difference time-domain numerical analysis, we examined the characteristics of conduit signals, which typically manifest in hyperbolic patterns. Particularly, we investigated three conduit arrangements: horizontal, vertical, and diagonal. Automatic gain control was applied to amplify the signals, enabling the analysis of variations in shadow regions and signal characteristics for each arrangement. In the horizontal arrangement, the proximity of the two conduits resulted in the emergence of a new hyperbolic pattern between the existing conduits. In the vertical arrangement, the lower conduit could be detected using hyperbolic signals on either side, but the detection was challenging when the upper conduit diameter exceeded that of the lower conduit. In the diagonal arrangement, signal characteristics varied based on the position of shadow regions relative to the detection range of the equipment. Asymmetrical signal patterns were observed when the shadow regions fell within the detection range, whereas the signals of the two conduits were minimally impacted when the shadow regions were outside the detection range. This study provides vital insights into accurately detecting and characterizing subsurface multichannel conduits using GPR-a significant contribution to the field of subsurface exploration and management.

• Journal of Internet Computing and Services
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• v.5 no.5
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• pp.79-91
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• 2004

This paper proposes avatar face generation system that uses shading mechanism and facial features extraction method of facial recognition. Proposed system generates avatar face similar to human face automatically using facial features that extracted from a photo. And proposed system is an approach which compose shade and facial features. Thus, it has advantages that can make more realistic avatar face similar to human face. This paper proposes new eye localization method, facial features extraction method, classification method for minimizing retrieval time, image retrieval method by similarity measure, and realistic avatar face generation method by mapping facial features with shaded face pane.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1439-1444
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• 2005

AIS needs hish efficiency and safety in terms of operational management and, in the aspect of service range, it is time to minimize shadow regions through propagation evaluation of AIS transmitter. Thus this study analyzes shadow regions and the scope of propagation of waves from stations through the electric wave environment of AIS. First, this study examines the characteristics of AIS wave and draws up methods to analyze the scope of propagation of waves according to the characteristics. Second, this study finds out service regions and shadow regions of the 22 stations across the nation by analyzing the actual data based on climate and topography. Lastly, this study summarizes the results of wave conductivity evaluation and conductivity problems and proposes improvement measures.

• 한국지형공간정보학회:학술대회논문집
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• 2002.03a
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• pp.48-53
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• 2002

본 연구에서는 각각 1998년 8월 12일(홍수 발생시), 8월 19일(홍수 발생 후) 옥천, 보은 지역을 촬영한 RADARSAT SAR 위성영상을 이용하여 수계지역 및 홍수지역 분류를 수행하고자 하였다. 이를 위해, 먼저 두 장의 위성영상에 대해서 각각 스페클 잡영(speckle noise)을 제거하고, ${\sigma}^0$(sigma naught, dB)을 계산한 후 수계지역에 대한 ${\sigma}^0$값을 분석하였다. 이 값을 기준으로 각각 두 장의 위성영상에서 각각 최대우도법을 이용하여 수계지역을 분류하였다. SAR 영상은 영상취득의 원리에 의해 지형의 기복에 따른 음영효과(shadow effect)가 발생하는데, 음영효과가 발생하는 지역의 ${\sigma}^0$값은 수계지역과 비슷한 반사특성(낮은 dB 값)을 보인다. 따라서 지형의 기복이 심한 지역의 수계지역 분류시 음영효과를 제거해야 효과적적인 분류를 할 수 있으며, 이를 위해 위성의 헤더자료로부터 촬영시 각각의 촬영중심을 계산하고, 촬영중심과 지상좌표와의 기하학적 관계를 고려하여 음영효과를 제거하였다. 마지막으로, 수계지역만이 추출된 영상에 대해 영상의 기하보정을 수행하였으며, 기하 보정된 두장의 위성영상에 대해 차분영상를 생성함으로서 홍수지역을 분류하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.401-407
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• 2010

As according to utilizing mobile devices, the real time locating system to provide high quality service is required. RTLS based on wireless communication can be damaged from radio shadow areas which guarantee the line of sight. To cope with the radio shadow area, this paper proposes the performance improvement method using assistant tags and a directional antenna based reader. In addition, this paper also provides the design and implementation of RTLS and experiments for performance evaluation. The result shows that a success rate is increased up to 38% and accuracy is a CEP of 1.13 meters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.529-530
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• 2016

When the mountain accident occurred, the accident victims should inform anyone of information of the location and accident situation rapidly. But if you are in the radio shadow area where you cannot use GPS, 3G/4G, and wireless communication, you can't inform someone your accidents. In this paper, we suggest the emergency rescue request notification service in situation that victims can't report their accidents. This service is to send request message for rescue in radio shadow area, in mountain accident, by BLE(Bluetooth Low Energy).