• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1401-1404
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• 2004

점증하고 있는 무선망에서의 다양한 멀티미디어 서비스를 안정적으로 지원하기 위해서는 효율적인 대역폭 관리가 필수적이다. 본 논문에서는 차세대 네트워크의 기반이 되는 계층 셀 구조에서, 대역폭의 효율적인 관리를 지원하기 위한 통합 프레임워크를 제안하였다. 현재 트래픽의 과밀도와 사용자의 이동성을 기반으로 적절한 셀 선택, 대역폭 예약 및 재설정, 버퍼링 등의 알고리즘을 설계하였으며, 이들을 유기적으로 통합, 시스템 전반의 QoS를 향상시켰다.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.369-378
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• 2005

Document image is segmented and classified into text, picture, or table by a document layout analysis, and the words in table regions are significant for keyword spotting because they are more meaningful than the words in other regions. This paper proposes a method to extract words from table regions in document images. As word extraction from table regions is practically regarded extracting words from cell regions composing the table, it is necessary to extract the cell correctly. In the cell extraction module, table frame is extracted first by analyzing connected components, and then the intersection points are extracted from the table frame. We modify the false intersections using the correlation between the neighboring intersections, and extract the cells using the information of intersections. Text regions in the individual cells are located by using the connected components information that was obtained during the cell extraction module, and they are segmented into text lines by using projection profiles. Finally we divide the segmented lines into words using gap clustering and special symbol detection. The experiment performed on In table images that are extracted from Korean documents, and shows $99.16\%$ accuracy of word extraction.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.1
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• pp.49-57
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• 2005

ATM Form has defined the guaranteed frame rate (GFR) service to provide minimum cell rate (MCR) guarantees for TCP traffic in ATM networks and allow it to fairly share residual bandwidth. GFR switch implementation consists of the frame-based generic cell rate algorithm (F-GCRA) and a frame forwarding mechanism. The F-GCRA identifies frames that are eligible for an MCR guarantee. The frame forwarding mechanism buffers cells at a frame unit according to information provided by the F-GCRA and forwards the buffered cells to an output port according to its scheduling discipline. A simple GFR mechanism with shared buffer with a global threshold is a feasible implementation mechanism, but has been known that it is insufficient to guarantee the MCR. This paper has estimated performance of GFR service for TCP traffic over ATM switches with the simple FIFO-based mechanism

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.3A
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• pp.211-220
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• 2002

In this paper, we propose an efficient algorithm to compress simple computer cell animation at very low bit rate. The structure of proposed algorithm consists of intra frame coding and inter frame coding. In inter frame coding, animation is encoded by color quantization using a palette, rearrangement of index, ADPCM used in JPEG-LS, mapping, classification, and entropy coding. In interframe coding, classifying the characteristics of motion, animation is encoded by block based motion replenishment. Experimental results show that the proposed methods turns out to outperform conventional methods including Flash, FLC, Motion-JPEG, MPEG-1, and MPEG-4.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.48-50
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• 1998

메시지에 기반을 둔 다중컴퓨터는 프로세서들 간에 고속통신을 위한 연결 망을 요구한다. ATM 스위치는 대규모의 다중컴퓨터를 구성하기에 유리한 접근 방식을 제공하며, 낮은 지연시간과 고성능을 제공하는 특성을 가진다. 본 논문은 고속 ATM 스위치를 통한 프로세서들간의 정보를 송신/수신하는 셀 라우터를 설명한다. 고속 ATM 스위치를 효율적으로 사용하기 위하여, 본 논문은 다중화와 역 다중화를 가지고 계층적 구조를 제안한다. 일반 연결 망에서 라우팅을 위해 착신주소를 가지는 기본단위는 메시지이지만, ATM 망에서는 셀이라고 부르는 고정된 크기의 프레임이 기본단위이다. 셀은 VPI와 VCI를 가지며, 이는 송신/수신 프로세서의 구별자로서 사용된다 결론적으로 제안한 고속 셀 라우터와 계층적 구조는 메시지 전송지연의 관점에서 이점을 가질 수 있다.

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.61-70
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• 2011

IEEE 802.11 wireless network supports control frames like RTS/CTS(Request To Send / Clear To Send). Because they is defend to frame collection problems. It helps to solve the frame collection problem but decreases the throughput rate. Also, control frame makes False Node Problem. This problem is makes to other wireless nodes don't work and don't find channels in the same cell and near cells. We proposed a reformed new control frame for efficiency throughput rate and solution of False Node Problem. New control frame is to have added to 4 bytes of channel detection ability at the RTS frames. Channel detection ability supported to check channel at the wireless node start to transmit data frame, We expect that channel detection ability make prevent False Node Problem for increase to access number to channel. We perform comparative analysis in terms of delay(sec) and load(bits/sec) with reform RTS/CTS method which proves the efficiency of the proposed method.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.277-282
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• 2002

In general, requirements for QoS are different according to the type of services in wire-line and wireless ATM networks, and real-time video service is more sensitive to cell transmission delay than to cell loss. Existing handoff schemes emphasizing prevention of cell loss had limitations in cell transmission delay to satisfy QoS. In this paper, a novel scheme to transmit ATM cells with low CLP(when CLP = 0) prior to others and discarding cells with high CLP(when CLF = 1) in ATM cell header among cells to be forwarded to new base station during handoffs in real-time VBR service is proposed. The proposed scheme is proven to be suitable for the satisfaction of QoS of real-time VBR service and appropriate for fast handoffs by giving high CLP value to less meaningful MPEG frames through simulations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.3-8
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• 1997

본 논문에서는 광대역 무선가입자망 (LMCS; Local Multipoint Communication System)에서 사용하는 변복조 방식 및 구조에 대하여 살펴보고, ATM 셀 전송을 기본으로 하고 상 하향 같은 길이를 전제로 한 데이터 프레임 구조를 기반으로 해서 데이터 프레임 및 변복조 파라미터를 제시하였다. 그리고 여러 가입자에서 전달되는 상향 프레임의 동기화 방법 및 동기화를 위한 가입자 단말기 모뎀의 요구사항에 대하여 논하였다. 마지막으로 LMCS 서비스를 위한 LMCS 시스템 구조에 대하여 기지국 시스템과 단말기 시스템을 설계하여 제사하였다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.175-181
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• 1999

There are issues regarding how some of traffic parameters should be set so that ATM and non-ATM service parameters can be compatible. For example, policing method used by frame relay based on CIR(committed information rate) will not exactly match the ATM UPC(Usage Parameter Control) method. ATM and the frame relay have different transfer modes and traffic parameters. The cells and frames are police by their own traffic control schemes. For the same information, the real traffic of the ATM side takes greater bandwidth than that of the frame relay side caused by ATM cell format and AAL5 format. IN both networks this bandwidth than that of the frame relay side caused by ATM cell format and AAL5 format. In both networks this bandwidth ratio should be considered on traffic parameter mapping to maintain their QoS and to perform efficient network resource management. In this paper we describe traffic parameter mapping schemes between frame relay and ATM in ATM network and how to expect the bandwidth ratio to maintain FR QoS in ATM network. We assumed frame length distribution to Erlang or Exponential probability density function.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.133-142
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• 2012

In this paper, we propose and implement a high-speed algorithm for CGH that is to calculate digital hologram by modeling the interference phenomenon for tow lights. This algorithm changes the computation equations into a parallel-computable ones and implements it with a structure consisting of two kinds of cells (initial calculation cell, and update calculation cell). The parallel computation algorithm is to get the rest hologram pixels concurrently after calculation the first hologram column. Here, the initial calculation cells compute the first column of the hologram and the update calculation cells compute the rest of the hologram. The two kinds of cells performs a pipeline operation to complete the operations of the two cells at the same time. A CGH calculator to compute the hole hologram for a light source is structured by arranging the two kinds of cells. Results from simulation showed that the maximum operation frequency is about 215MHz. So, experiments are performed by setting this frequency and the same environments as the method showing the best performance. As the results, the proposed one could complete the computation of 81.75 CGH frames per second, while the previous method computes 62.9 CGH frames per second.