• Title, Summary, Keyword: T-TCP

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Analysis of Average Waiting Time and Average Turnaround Time in Web Environment (웹 환경에서의 평균 대기 시간 및 평균 반환 시간의 분석)

  • Lee, Yong-Jin
    • The KIPS Transactions:PartC
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    • v.9C no.6
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    • pp.865-874
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    • 2002
  • HTTP (HyperText Transfer Protocol) is a transfer protocol used by the World Wide Web distributed hypermedia system to retrieve the objects. Because HTTP is a connection oriented protocol, it uses TCP (Transmission control Protocol) as a transport layer. But it is known that HTTP interacts with TCP badly. it is discussed about factors affecting the performance or HTTP over TCP, the transaction time obtained by the per-transaction TCP connections for HTTP access and the TCP slow-start overheads, and the transaction time for T-TCP (Transaction TCP) which is one or methods improving the performance or HTTP over TCP. Average waiting time and average turnaround time are important parameters to satisfy QoS (Quality of Service) of end users. Formulas for calculating two parameters are derived. Such formulas can be used for the environment in which each TCP or T-TCP transaction time is same or different. Some experiments and computational experiences indicate that the proposed formulas are well acted, can be applied to the environment which the extension of bandwidth is necessary, and time characteristics of T-TCP are superior to that of TCP. Also, the load distribution method of web server based on the combination of bandwidths is discussed to reduce average waiting time and average turnaround time.

Minimizing Security Hole and Improving Performance in Stateful Inspection for TCP Connections (TCP연결의 스테이트풀 인스펙션에 있어서의 보안 약점 최소화 및 성능 향상 방법)

  • Kim, Hyo-Gon;Kang, In-Hye
    • Journal of KIISE:Information Networking
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    • v.32 no.4
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    • pp.443-451
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    • 2005
  • Stateful inspection devices must maintain flow information. These devices create the flow information also for network attack packets, and it can fatally inflate the dynamic memory allocation on stateful inspection devices under network attacks. The memory inflation leads to memory overflow and subsequent performance degradation. In this paper, we present a guideline to set the flow entry timeout for a stateful inspection device to remove harmful embryonic entries created by network attacks. Considering Transmission Control Protocol (TCP) if utilized by most of these attacks as well as legitimate traffic, we propose a parsimonious memory management guideline based on the design of the TCP and the analysis of real-life Internet traces. In particular, we demonstrate that for all practical purposes one should not reserve memory for an embryonic TCP connection with more than (R+T) seconds of inactivity where R=0, 3, 9 and $1\leqq{T}\leqq{2}$ depending on the load level.

A Simulated Annealing Method with Search Space Smoothing for T-Coloring Problem (T-칼라링 문제를 위한 탐색공간 스무딩 Simulated Annealing 방법)

  • Lee, Jung-Eun;Han, Chi-Geun
    • Journal of Korean Institute of Industrial Engineers
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    • v.25 no.2
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    • pp.226-232
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    • 1999
  • Graph Coloring Problem(GCP) is a problem of assigning different colors to nodes which are connected by an edge. An extended form of GCP is TCP (T-coloring problem) and, in TCP, edge weights are added to GCP and it is possible to extend GCP's applications. To solve TCP, in this paper, we propose an improved Simulated Annealing(SA) method with search space smoothing. It has been observed that the improved SA method obtains better results than SA does.

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End-to-end MQTT security protocol using elliptic curve cryptography algorithm (타원곡선암호 알고리즘을 이용한 종단간 MQTT 보안 프로토콜)

  • Min, Jung-Hwan;Kim, Young-Gon
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.19 no.5
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    • pp.1-8
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    • 2019
  • Internet of Things (IoT) is proliferating to provide more intelligent services by interconnecting various Internet devices, and TCP based MQTT is being used as a standard communication protocol of the IoT. Although it is recommended to use TLS/SSL security protocol for TCP with MQTT-based IoT devices, encryption and decryption performance degenerates when applied to low-specification / low-capacity IoT devices. In this paper, we propose an end-to-end message security protocol using elliptic curve cryptosystem, a lightweight encryption algorithm, which improves performance on both sides of the client and server, based on the simulation of TLS/SSL and the proposed protocol.

The Behavior of TCP over UBR-EPD with multiple VBR source (다중 VBR 소스를 갖는 TCP over UBR-EPD의 특성)

  • Lee, Jin-Woo;Kim, Jin-Tae;Yoo, Young-Kil
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.36T no.4
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    • pp.82-87
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    • 1999
  • The Asynchronous Transfer Mode(ATM) networks are being adopted as backbones over various parts of Internet. TCP is one of the most widespread transport protocols and can be used with ATM. But, TCP shows poor end-to-end performance on ATM networks. Effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. As congested link transmits cells from corrupted packets, it wastes bandwidth and throughput becomes low. This paper examines the behavior of TCP over ATM-UBR using EPD switch in a broadband environment. As threshold value closes to the buffer size, the buffer can be used more efficiently, but more drops and retransmission occur. If the threshold value is much less than buffer size, efficiency becomes low, but few drops can be happen. Therefore, the decision of threshold value becomes important factor.

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Comparative Genomics of T-complex protein 10 like in Humans and Chimpanzees

  • Kim, Il-Chul;Kim, Dae-Soo;Kim, Dae-Won;Choi, Sang-Haeng;Choi, Han-Ho;Chae, Sung-Hwa;Park, Hong-Seog
    • Genomics & Informatics
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    • v.3 no.2
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    • pp.61-65
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    • 2005
  • Comparing 231 genes on chimpanzee chromosome 22 with their orthologous on human chromosome 21, we have found that 15 orthologs have indels within their coding sequences. It was rather surprising that significant number of genes have changed by indel, despite the shorter time since their divergence and led us hypothesize that indels and structural changes may represent one of the major mechanism of proteome evolution in the higher primates. Human T-complex protein 10 like (TCP 10L) is a representative having indel within its coding sequence. Gene structure of human TCP10L compared with chimpanzee TCP10L gene showed 16 base pair difference in genomic DNA. As a result of the indel, frame shift mutation occurs in coding sequence (CDS) and human TCP10L express longer polypeptide of 21 amino acid residues than that of chimpanzee. Our prediction found that the indel may affect to dramatic change of secondary protein structure between human and chimpanzee TCP10L. Especially, the structural changes in the C-terminal region of TCP10L protein may affect on the interacting potential to other proteins rather than DNA binding function of the protein. Through these changes, TCP10L might influence gene expression profiles in liver and testis and subsequently influence the physiological changes required in primate evolution.

A design and implementation of transmit/receive model to speed up the transmission of large string-data sets in TCP/IP socket communication (TCP/IP 소켓통신에서 대용량 스트링 데이터의 전송 속도를 높이기 위한 송수신 모델 설계 및 구현)

  • Kang, Dong-Jo;Park, Hyun-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.4
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    • pp.885-892
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    • 2013
  • In the model Utilizing the TCP / IP socket communication to transmit and receive data, if the size of data is small and if data-transmission aren't frequently requested, the importance of communication speed between a server and a client isn't emphasized. But nowadays, it has emerged for large amounts of data transfer requests and frequent data transfer request. This paper propose the TCP/IP communication model that can be improved the data transfer rate in multi-core environment by changing the receiving structure of the client to receive large amounts of data and the transmission structure of the server to send large amounts of data.

The Effect of Electroacupuncture at the ST36 on the Electroencephalogram (족삼리(ST36) 전침 자극이 뇌파에 미치는 영향)

  • Gwon, Sun-Cheol;Youn, Dae-Sik;Lee, Sang-Ryong
    • Korean Journal of Acupuncture
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    • v.23 no.1
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    • pp.15-36
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    • 2006
  • Objectives . The aim of this study was to examine the effect of electroacupuncture(EA) at the ST36 on normal humans by using power spectral analysis. Methods : EEG(Electroencephalogram) power spectral exhibits site-specific and state-related differences in specific frequency bands. In this study, power spectrum was used as a measure of complexity. 32 channel EEG study was carried out in 12 subjects (10 males; age=26.7 years old, 2females; age=28 years old). Results ; In ${\alpha}$ (alpha) band, the power values at Fp2, F7, F3, Fz, FTC1, FTC2, T3, C3, Cz, C4, TT1, TCP1, CP1, CP2,T5, P3, Pz, P4, Po1, Po2, O1, Oz,O2 channels(p<0.05) during the ST36-acupoint treatment were significantly increased. In ${\beta}$ (beta) band, the power values at Fp2, F7, F3, Fz, F4, F8, FTC1, FTC2, T3, C3, Cz, C4, TT1, TCP1, CP1, CP2, T5, P3, Pz, P4, Po1, Po2, O1, Oz, O2 channels(p<0.05) during the ST36-acupoint treatment were significantly decreased. In ${\delta}$ (delta) band, the power values at F7, Fz, T3, C3, TT1, TCP1, CP1, CP2, T5, P3, Pz,T6, Po1, PO2,O1, Oz, O2 channels(p<0.05) during the ST36-acupoint treatment were significantly decreased. In ${\theta}$(theta) band, the power values at F7, Fz, FTC1, T3, TCP1, CP2, TCP2, Po1, Po2 channels(p<0.05) during the ST36-acupoint treatment were significantly decreased. ${\alpha}$/${\beta}$ values at Cz, T5, O1, Oz, O2 channels during the ST36-acupoint treatment were increased. ${\beta}$/${\theta}$ values at Fpl, F7, F3, Fz, F4, F8, FTC1, FTC2, T3, C3, C4, T4, TT1, TCP1, TCP2, TT2, P3, P4, T6, Pol channels during the ST36-acupoint treatment were increased. Conclusions : This results suggest that Electroacupuncture at the ST36 mostly affects the charge on alpha(23 channels), beta(25 channels) bands.

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Enhancements of T-REFWA to Mitigate Link Error-Related Degradations in Hybrid Wired/Wireless Networks

  • Nishiyama, Hiraki;Taleb, Tarik;Nemoto, Yoshiaki;Jamalipour, Abbas;Kato, Nei
    • Journal of Communications and Networks
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    • v.8 no.4
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    • pp.391-400
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    • 2006
  • With the on-going wireless access technologies, the Internet has become accessible anytime anywhere. In wireless networks, link errors significantly degrade the performance of the transmission control protocol (TCP). To cope with this issue, this paper improves the recently-proposed terrestrial REFWA (T-REFWA) scheme by adding a new error recovery mechanism to its original design. In the T-REFWA scheme, senders are acknowledged with appropriate sending rates at which an efficient and fair utilization of network resources can be achieved. As the feedback values are computed independently of link errors, senders can keep transmitting data at high rates even in case of link error occurrences. Using this feature, the proposed error recovery mechanism can achieve high throughput in environments with high bit error rates. The throughput is further improved by disabling the exponential back-off algorithm of TCP so that long idle times are avoided in case of link errors. We show through simulations that the proposed method improves TCP performance in high bit error rates. Compared with several TCP variants, the proposed error recovery scheme exhibits higher link utilization and guarantees system fairness for different bit error rates.

Implementation and Performance Evaluation of Transaction Protocol for Wireless Internet Services (무선 인터넷 서비스를 위한 트랜잭션 프로토콜의 구현과 성능평가)

  • Choi, Yoon-Suk;Lim, Kyung-Shik
    • Journal of KIISE:Information Networking
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    • v.29 no.4
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    • pp.447-458
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    • 2002
  • In this paper, we design and implement Wireless Transaction Protocol(WTP) and evaluate it for wireless transaction processing in mobile computing environments. The design and implementation of WTP are based on the coroutine model that might be suitable for light-weight portable devices. We test the compatibility between our product and the other products such as Nokia, Kannel and WinWAP For the evaluation of WTP, we use an Internet simulator that can arbitrary generate random wireless errors based on the Gilbert model. In our experiment, the performance of WTP is measured and compared to those of Transmission Control Protocol(TCP) and TCP for Transactions. The experiment shows that WTP outperforms the other two protocols for wireless transaction processing in terms of throughput and delay. Especially, WTP shows much higher performance In ease of high error rate and high probability of burst errors. This comes from the fact that WTP uses a small number of packets to process a transaction compared to the other two protocols and introduces a fixed time interval for retransmission instead of the exponential backoff algorithm. The experiment also shows that the WTP performance is optimized when the retransmission counter is set to 5 or 6 in case of high burst error rate.