• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1767-1772
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• 2006

Computer-generated integral imaging system is an auto-stereoscopic display system that users can see and feel the stereoscopic images when they see the pre-rendered elemental images through a lens array. The process of constructing elemental images using computer graphics is called image mapping. Viewpoint vector rendering (VVR) method is one of the image mapping algorithm specially designed for real-time graphics applications, which would not be affected by the size of the rendered objects or the number of elemental lenses used in the integral imaging system. This paper describes a new VVR framework which improved its rendering performance considerably. It also compares the previous VVR implementation with the new VVR work utilizing GPU and shows that newer implementation shows pretty big improvements over the old method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2363-2369
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• 2016

In this paper, we propose three-dimensional (3D) quick-response (QR) code generation technique using passive 3D integral imaging and computational integral imaging reconstruction technique. In our proposed method, we divide 2D QR code into 4 planes with different reconstruction depths and then we generate 3D QR code using synthetic aperture integral imaging and computational reconstruction. In this 3D QR code generation process, we use integral imaging which is one of 3D imaging technologies. Finally, 3D QR code can be scanned by reconstructing and merging 3D QR codes at 4 different planes with computational reconstruction. Therefore, the security level for QR code scanning may be enhanced when QR code is scanned. To show that our proposed method can improve the security level for QR code scanning, in this paper, we carry out the optical experiments and computational reconstruction. In addition, we show that 3D QR code can be scanned when reconstruction depths are known.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.171-176
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• 2004

A light deflector integrated laser diode(LD) was fabricated and the characteristics of LD and ourput beam deflection as a function of deflector injection current were measured. To integrate the deflector with LD, a passive waveguide was integrated with the LD and a triangular-type light deflector was fabricated on the upper clad of the passive waveguide section. Light deflection from the fabricated light deflector is controlled by the effective refractive index variation induced by carrier injection. To characterize the effect of the deflector injection current, threshold current, slope efficiency, and output beam spectrum were measured as a function of deflector injection current. From these measured data, the increment in the threshold current and the decrement of the slope efficiency were observed. However, the output beam spectrum was not affected by the deflector. The Beam Propagation Method(BPM) was used to simulate the proposed device and the light deflection was measured by the far-field pattern of the output beam as a function of the deflector injection current. In the fabricated deflector integrated LD, the deflection angle of 1.9$^{\circ}$ at the injection current of 15 ㎃ was obtained.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.3
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• pp.273-296
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• 2006

The purpose of this paper is to investigate the formation and characteristics of Gwangju photonics agglomeration as a new agglomeration with a new industry. Data used in this study are locally investigatedfirm related data and the result of questionnaire surveys. Major findings are as follows. First, in the viewpoint of policy, national government suggested the whole policy frameworks and financial support for the strategic industrial development. Regional government picked up and fostered the strategic industry. The initial support of the national government and role of regional government triggered the initial development of the agglomeration. Second, in the spatial perspective, Gwangju photonics agglomeration is based on the externalities of knowledge and technology as well as the input-output network within value chains of production. There is a possibility that Gwangju photonics agglomeration will be developed as an innovation cluster of knowledge-based economy in the future beyond a mere production base of photonics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1748-1758
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• 1994

Recently, the demand of mobile communication is rapidly increasing. Also, not only the voice service but also the nonvoice services such as data, FAX, and image service are required. Therefore, in this paper, the voice/data intergraed service methods that will be utilized as a basic core technology of the PCS systems are proposed and their performances are analyzed and compared by computer simulation. According to the simulation results, it could be seen that the performance of voice/data integrated PR-CDMA method is better than that of voice/data integrated broadband CDMA method using a dedicated terminal or a voice/data integrated terminal. The reason is that the voice/data integrated PR-CDMA method can overcome the weak points of CDMA protocol, such as a limitation of the fixed CDMA logical channel number and a falling-off in channel utilization, by using PRMA protocol as a multiple access method that the terminals to which a CDMA logical channel is assigned compete.

• Journal of Internet Computing and Services
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• v.12 no.5
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• pp.113-125
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• 2011

As information resources have become more various and the number of the resources has increased, knowledge customization on the social web has been becoming more difficult. To reduce the burden, we offer a framework for context-based similarity calculation for knowledge customization using ontology on the CBR. Thereby, we newly developed context- and intensity-based similarity calculation methods which are applied to extraction of the most similar case considered semantic similarity and syntactic, and effective creation of the user-tailored knowledge using the selected case. The process is comprised of conversion of unstructured web information into cases, extraction of an appropriate case according to the user requirements, and customization of the knowledge using the selected case. In the experimental section, the effectiveness of the developed similarity methods are compared with other edge-counting similarity methods using two classes which are compared with each other. It shows that our framework leads higher similarity values for conceptually close classes compared with other methods.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.4
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• pp.688-701
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• 2014

This article is focused on the agglomeration and decline factors of the footwear industries in Busan metropolitan area from the industrial cluster point of perspective. For the research, 'the components and network of industrial cluster model' are presented which is restructured of M. Porter's cluster model. Moreover, this research have examined the agglomeration and decline process of the footwear industries in Busan area and conducted a survey targeting footwear enterprises in Busan area. In the late 1980's, the footwear industries in Busan area formed the largest footwear industrial cluster in the world. However, the industrial cluster started to decline from early 1990's and now it is reduced in to 1/10 size of the past. The growth factors of Busan footwear industrial cluster include cheap and plentiful labours, penetration of OEM production, entrepreneur spirit, human resources network, government's support and so on. Moreover, the agglomeration of relative companies also created high competitiveness in this cluster. The decay factors are pointed out sudden rise of labour cost, shortage of factory site, rise of land price, alteration of government policy, international relocation of footwear production and growth of overseas industrial cluster. Busan footwear industrial cluster nowadays has declined in its size, but it is the only footwear industrial cluster in Korea.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.1-10
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• 2015

In this paper, we propose an integral image compression method to improve the coding efficiency. As the characteristics of integral images are various according to the distance between a camera and objects, complexity of the objects and background, etc, the coding efficiency can be improved by applying a coding method adaptive to the characteristics. In addition, as the integral images are compressed by the unit of elemental images, the coding efficiency can be improved. by employing a coding method optimized to the coding direction of elemental images. Therefore, the proposed method remaps an integral image with six kinds of mapping rules, and then the conventional 3D-DCT based compression method is applied to the remapped images. Finally, we perform the rate-distortion optimization to choose the best of the mapping rules. Experimental results show that the proposed method yields high gains in image quality and bit-rate.

• Journal of the Economic Geographical Society of Korea
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• v.8 no.2
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• pp.195-215
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• 2005

This study was carried into execution to analyze Spatial Characteristics of Seoul Business Services Cluster in circumstance of local economic development led by knowledge-intensive business services. The analysis was performed for industrial agglomeration and companies' linkage and network. As the result, there are three business services cluster, including the largest one in Gang-Nam Gu, Seoul, and for last 10 years, there has been increasing development of business services cluster. In the meanwhile, their linkage and network have not been performed briskly. Therefore, from now on, a plan that can help companies' linkage and network performed inside of cluster to have active and international structure has to be considered in cluster policy.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.336-344
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• 2020

The prediction and evaluation of driftwood accumulation around river-crossing structures are essential because driftwood accumulation increases during flood disasters. In this study, the driftwood accumulation and behavior around bridge piers were evaluated via a numerical model that could be employed to analyze three-dimensional turbulent flow and driftwood motion. The moving particle semi-implicit-based model for driftwood motion was sensitive to the number of spheres. The numerical results showed that the approach velocity and the ratio of driftwood length to pier width were the key factors influencing driftwood accumulation, whereas the driftwood density had only a minor influence. Overall, it is expected that this study will contribute to the development of improved risk evaluation indexes for assessing driftwood accumulation around river-crossing structures.