• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.3
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• pp.471-489
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• 2013

Data compression at the transport layer could both reduce transmitted bytes over network links and increase the transmitted application data (TCP PDU) in one RTT at the same network conditions. Therefore, it is able to improve transmission efficiency on Internet, especially on the networks with limited bandwidth or long delay links. In this paper, we propose an on-the-fly TCP data compression scheme, i.e., the TCPComp, to enhance TCP performance. This scheme is primarily composed of the compression decision mechanism and the compression ratio estimation algorithm. When the application data arrives at the transport layer, the compression decision mechanism is applied to determine which data block could be compressed. The compression ratio estimation algorithm is employed to predict compression ratios of upcoming application data for determining the proper size of the next data block so as to maximize compression efficiency. Furthermore, the assessment criteria for TCP data compression scheme are systematically developed. Experimental results show that the scheme can effectively reduce transmitted TCP segments and bytes, leading to greater transmission efficiency compared with the standard TCP and other TCP compression schemes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.4
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• pp.1-8
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• 2000

A defect of decrease in TCP throughput can be investigated in asymmetric environment of different uplink and downlink bandwidths. Under two-way TCP traffic, the total link utilization is decreased by the successive injection of data packets in buffer. To solve these problems, terminal ACK filtering and packet scheduling mechanisms are introduced in this paper. ACK filtering eliminates the buffered ACK packets and transmits recent ACK packets in the uplink with limited bandwidth. Packet scheduling is the method of preventing 'clustering' and 'ack compression' states which are generated in the two-way TCP traffic. The guarantee of the data traffic in reverse TCP connection and the high throughput in forward TCP connection are investigated by simulation.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.207-210
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• 2003

In this paper, we have implemented the DVR system which is controlled far away, and added a function of TCP/IP Network for image data and control signal transmission, the DVR system has the advantage of easy to search and of no loss in stored quality. The continuously declining price of the hard drive presents the opportunity for the DVR system to displace the analog system. Also, with spread of the internet the needs of PC based the DVR system increase. Therefore, we have implemented DVR system within a function of network. When obtained image through the PTZ camera is transmitted to digital form, very large space of storage is required, hence image compression is essential. We use JPEG2000 for compression of image. JPEG2000 adopt DWT by means of transform. DWT concentrates important information of image on subband and has feature of multi-resolution. It is effective in order to express image. Thus JPEG2000 is suitable for image compression in DVR system. The significance of this paper is to design the DVR system which is controlled through TCP/IP network and to implement transmission of image compression using JPEG2000.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.653-660
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• 2013

This paper deals with the problem of unfairness among uplink TCP (Transmission Control Protocol) flows associated with frame aggregation employed in IEEE 802.11n WLANs (Wireless Local Area Networks). When multiple stations have uplink TCP flows and transmit TCP data packets to an AP (Access Point), the AP has to compete for channel access with stations for the transmission of TCP ACK (acknowledgement) packets to the stations. Due to this contention-based channel access, TCP ACKs tend to be accumulated in the AP's downlink buffer. We show that the frame aggregation in the MAC (Medium Access Control) layer increases TCP ACK losses in the AP and leads to the serious unfair operation of TCP congestion control. To resolve this problem, we propose the TAC (TCP ACK Compression) mechanism operating at the top of the AP's interface queue. By exploiting the properties of cumulative TCP ACK and frame aggregation, TAC serves only the representative TCP ACK without serving redundant TCP ACKs. Therefore, TAC reduces queue occupancy and prevents ACK losses due to buffer overflow, which significantly contributes to fairness among uplink TCP flows. Also, TAC enhances the channel efficiency by not transmitting unnecessary TCP ACKs. The simulation results show that TAC tightly assures fairness under various network conditions while increasing the aggregate throughput, compared to the existing schemes.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1653-1656
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• 2003

In this paper, we implemented a web-based communication system using Motion JPEG and RTP. MJPEG compression method is used for compression of the image in order to film and transmit the moving image information in the real time, and the RTP(Real-Time Transport Protocol) which differs from the existing TCP and UDP is used for the data transmission.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.355-358
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• 2002

In this paper, we propose RTP(Real-Time Transport Protocol) based image transport system to transport still images in real-time after JPEG2000 compression, which is still image compression standard for next generation. To add RTP packet on UDP packet, the image transport system inserts packetizer and depacketizer process into transmitter and receiver of RTP data, respectively. We apply the proposed system to several image and compare the transport time to TCP-based method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1811-1818
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• 2009

This paper is about the research to maintain and enhance the flow of data of the wireless traffic control. Various types of burst traffic that were found at TCP window flow control have been removed or mitigated using the two-way traffic control. Currently, TCP ACK Compression problem appears during the transmission of the wireless communication control channel because the queues are mostly located at the end system. Therefore, in this paper, the periodic bursty characterist of the source IP queue wilt be analyzed to predict the maximum value of queues. And then the prediction tool will be applied to wireless communication traffic control to handle symmetric traffic as to increase the throughput and improve the performance.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.148-152
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• 2007

This paper develops an integrated optic transmitter/receiver based on ring-type WDM PON. The optic transmitter/receiver can transmit real-time images from the CCTV of a remote street without compression and transmit TCP/IP data using an optic fiber. This system can also perform remote controls of the CCTV camera. The developed optic transmitter/receiver can provide the monitoring service of an advanced image quality of remote traffic using a broadband technology.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.14-20
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• 2002

In this paper, we proposed the compression technique of the video data using SPIHT(set partitioning in hierarchical trees) based on wavelet and the multi-stream delivery method for best-effort service as fully utilizing the clients bandwidth over the current Internet. The experiment shows that the proposed method provides about 1.5dB better picture quality without block effects than DCT(discrete consine transform) based coding schemes at the same bit rates because of using the wavelet video coder. In addition, this technique implements the multi-stream transmission based on TCP(transmission control protocol). Thus, it is provided with the best-efforts service which is robust to the network jitter problem, and maximally utilizes the bandwidth of the client's.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.704-711
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• 2003

Recently, the demands for real-time service and multimedia data are rapidly increasing. There are significant redundancies between header fields both within the same packet header and in consecutive packets belonging to the same packet stream. But there are many overheads in using the current UDP/IP protocol. Header compression is considered to enhance the transmission efficiency for small size of payload. By sending the static field information only once initially and by utilizing dependencies and predictability for other fields, the header size can be significantly reduced for most packets. This work describes an implementation for header compression of the headers of U/UDP protocols to reduce overhead on Ethernet network. Typical UDP/IP Header packets can be compressed down to 7 bytes and the header compression system is designed and implemented on the Linux environment. Using the designed Header compression system between a server and a client have the advantage of effective data throughput in network.