• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.308-317
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• 2008

The objects real time rendered in the 3D cyber space can interact with each others according to the events which are happened when satisfying some conditions. But to representing the behaviors with these interactions, too many event conditions are considered because each behavior pattern and event must be corresponded in a one-to-one ratio. It leads to problems which increase the system complexity. So, in this paper, we try to physical method based on elasticity force for representing more realistic behaviors of AI fish and apply to the deformable multi-detection sensor, so we suggest the new method which can create the various behavior patterns responding to one evasion event.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.360-365
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• 2007

Jakarta Slide는 아파치 프로젝트 중의 하나로 개발된 WebDAV 서버로서 인터넷 통하여 다양한 콘텐츠의 비동기적인 협업 활동을 지원한다. 하지만 WebDAV 프로토콜은 사용자와 그룹을 위한 작업공간을 명시적으로 지원하지 않기 때문에, Jakarta Slide를 통하여 복잡한 협업을 수행하기는 매우 어렵다. CoSlide는 이러한 문제점을 개선하기 위하여 Jakarta Slide를 확장한 협업시스템으로서 다수의 사용자와 그룹을 위한 다양한 작업공간을 제공하여 효과적인 협업 환경을 제공한다. 협업시스템을 통하여 복잡한 협업을 보다 효과적으로 수행하기 위해서는 협업 참여자들 간에 실시간적인 통신이 원활이 이루어져야 할 필요성이 있다. 본 논문은 CoSlide 협업시스템에서 실시간 메시징을 지원하기 위한 CoJBother 메신저 클라이언트의 개발에 대하여 기술한다. 개발된 CoJBother는 협업시스템의 사용자와 그룹을 정의하기 위하여 개발된 Jabber 프로토콜을 사용하며, 또한 이를 지원하기 위하여 개발된 메신저 서버와 함께 동작한다. 사용자는 CoJBother를 통하여 협업시스템의 작업그룹에 참여하는 사용자들을 확인하고 자동적인 그룹채팅 기능을 사용함으로써 그룹 참여자들과 협업 수행을 위한 원활한 의사소통을 할 수 있다.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.304-311
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• 2007

플래시 기반의 wall pad에서 보여줄 수 있는 그래픽 인터페이스의 방향은 크게 세가지로 구분할 수 있다. 첫 번째, 디스플레이 내의 자유로운 공간 이동이다. Wall pad의 주요한 기능은 제품의 원격제어이며 디스플레이에서 각 제품의 위치와 상태를 표시해 주는 것이다. 그러나 한정된 디스플레이 내에서 이러한 동작은 쉽지 않다. 플래시 기반의 환경에서 자유로운 zoom in, out을 통해 제품에 대한 정보를 명확하게 전달 가능하게 된다. 두 번째, 사용자의 감성 만족도를 극대화하는 측면이다. 감성 만족도를 높이기 위하여 모바일 제품에서도 대기화면 등에 다양한 요소를 적용하고 있다. 다만 본 제품은 모바일 제품과는 달리 항상 거실의 고정된 위치에서 보여지게 된다는 환경적 제약을 가지고 있다. 따라서 이를 활용하여 그 자체로 하나의 거실 인테리어 소품이 되어 전체 거실의 분위기를 한층 돋보이게 하는 역할까지도 가능하다. 세 번째, 메뉴 전개 방식에 활용 가능하다. 기능이 다양해지고 복잡해질수록 메뉴를 찾아 들어가는 일은 어렵고 복잡해지기 쉽다. 이러한 문제는 시간과 공간의 개념을 활용한 메뉴 전개를 통해 플래시를 활용하여 좀 더 직관적이고 인공지능적인 메뉴 방식으로 접근이 가능해진다. 이와 같이 홈 네트워크 인터페이스에서 플래시를 활용하는 것은 큰 의미가 있으며 실제 제품에 최적화해 가는 과정에서 그 효과를 얼마나 유지할 수 있느냐에 대한 문제가 가장 중요한 이슈가 될 것이다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.3
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• pp.283-293
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• 2008

A study of interactive ground behaviour due to tunnelling adjacent to existing piles has not been recognized well for the most geotechnical engineers so far. Because this is a very sophisticated boundary condition problem. In this study, therefore, the author has conducted both the laboratory model test and finite element analysis (FEA) to figure out such a complicated ground behaviour related to shear strain formations. Based on the model testing and FEA results, a boundary line which divides into two distinctive shear strain formations in relation to the locations of end-bearing pile tips was proposed. The author believes that the proposed boundary line may be helpful for planning the appropriate tunnel positions for avoiding damage of buildings which supported by piled-foundations in urban areas.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.655-664
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• 2001

The continuous data such as video streams and voice analog signals can be modeled as multidimensional data sequences(MDS's) in the feature space, In this paper, we investigate the clustering technique for multidimensional data sequence, Each sequence is represented by a small number by hyper rectangular clusters for subsequent storage and similarity search processing. We present a linear clustering algorithm that guarantees a predefined level of clustering quality and show its effectiveness via experiments on various video data sets.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.3
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• pp.265-274
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• 2010

In many tunnels, falling or sliding of rock blocks often occur, which cannot be predicted because of the complexity of rock discontinuities and it has brought an exponential increase in costs and time to manage. It is difficult to estimate the properties of rock masses before the tunnel excavation. The observational design and construction method in tunnels has been becoming important recently. In this study, a new hybrid stochastic-deterministic rock block analysis method for the prediction of the unstable rock blocks before the tunnel excavation is proposed, and then applied to the tunnel construction based on actual rock discontinuity information observed in the field. The comparisons and investigations with the analytical results in the tunnel construction have confirmed the validity and applicability of this new hybrid stochastic-deterministic rock block analysis method in tunnels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.673-681
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• 2011

In this paper, we design multiple antenna relay transmission schemes of low complexity to enhance the spatial diversity in orthogonal frequency division multiplexing (OFDM) systems. The relay scheme underlined, can provide space time block coding (STBC) of OFDM signals in the time domain without IFFT and FFT operations with much reduced complexity. In this paper, we modify the conventional low-complexity STBC-OFDM relaying scheme to be compatible to the existing OFDM systems. In addition, we extend the proposed scheme for multiple antenna relays and provide performance enhancement strategies according to the channel quality information available at the relay. The proposed scheme is shown to improve the diversity and thereby to reduce the outage probability and coded bit error rate. Therefore, the proposed scheme will be promising for service quality improvement or coverage extension based on OFDM like wireless LANs and maritime communications.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.749-756
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• 2010

The signal space diversity is one of the promising transmission techniques in next generation mobile TV service. However, DVB-T2 does not consider the multiple antennas (MIMO) so that the cyclic Q-delay method, a component interleaver in DVB-T2, causes a critical issue in detecting symbols at the receiver side by increasing the inter-symbol dependency. To solve this problem, the component-swapping technique is proposed, which limits the inter-symbol dependency in order to reduce detection complexity. In this paper, the achievable gain of a component-swapping technique combined with 16K LDPC code defined in DVB-T2 is evaluated by computer simulations. From the results, the gain is confirmed in terms of BER and receive complexity compared to legacy component interleaver methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.57-66
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• 2014

This paper presents a low-complexity barrel distortion correction processor for wide-angle cameras. The proposed processor performs the barrel distortion correction jointly with the color demosaicking, so that the hardware complexity can be reduced significantly. In addition, to reduce the required memory bandwidth, an efficient memory interface is proposed by utilizing the spatial locality of the memory access in the correction process. The proposed processor is implemented with 35K logic gates in a $0.11-{\mu}m$ CMOS process and its correction speed is 150 Mpixels/s at the operating frequency of 606MHz, where the supported frame size is $2048{\times}2048$ and the required memory bandwidth is 1 read/cycle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2391-2400
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• 1999

Vector quantizer (VQ) is an efficient data compression technique for low bit rate applications. However, the major disadvantage of VQ is its encoding complexity which increases dramatically as the vector dimension and bit rate increase. Even though one can use a modified VQ to reduce the encoding complexity, it is nearly impossible to implement such a VQ at a high bit rate or for a large vector dimension because of the enormously large memory requirement for the codebook and the very large training sequence (TS) size. To overcome this difficulty, in this paper we propose a novel structurally constrained VQ for the high bit rate and the large vector dimension cases in order to obtain VQ-level performance. Furthermore, this VQ can be extended to the low bit rate applications. The proposed quantization scheme has a form of feed-forward adaptive quantizer with a short adaptation period. Hence, we call this quantization scheme sample-adaptive product quantizer (SAPQ). SAPQ can provide a 2 ~3dB improvement over the Lloyd-Max scalar quantizers.