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Sample records for carrying tcp traffic

  1. Analytical Models for Energy Consumption in Infrastructure WLAN STAs Carrying TCP Traffic

    CERN Document Server

    Agrawal, Pranav; Kuri, Joy; Panda, Manoj; Navda, Vishnu; Ramjee, Ramachandran

    2009-01-01

    We develop analytical models for estimating the energy spent by stations (STAs) in infrastructure WLANs when performing TCP controlled file downloads. We focus on the energy spent in radio communication when the STAs are in the Continuously Active Mode (CAM), or in the static Power Save Mode (PSM). Our approach is to develop accurate models for obtaining the fraction of times the STA radios spend in idling, receiving and transmitting. We discuss two traffic models for each mode of operation: (i) each STA performs one large file download, and (ii) the STAs perform short file transfers. We evaluate the rate of STA energy expenditure with long file downloads, and show that static PSM is worse than just using CAM. For short file downloads we compute the number of file downloads that can be completed with given battery capacity, and show that PSM performs better than CAM for this case. We provide a validation of our analytical models using the NS-2 simulator. In contrast to earlier work on analytical modeling of P...

  2. Dynamics of TCP traffic over ATM networks

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, S. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.; Romanow, A. [Sun Microsystems Inc., Mountain View, CA (United States)

    1994-08-01

    The authors investigate the performance of TCP (Transport Control Protocol) connections over ATM (Asynchronous Transfer Mode) networks without ATM-level congestion control, and compare it to the performance of TCP over packet-based networks. For simulations of congested networks, the effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. The low throughput is due to wasted bandwidth as the congested link transmits cells from ``corrupted`` packets, i.e., packets in which at least one cell is dropped by the switch. This fragmentation effect can be corrected and high throughput can be achieved if the switch drops whole packets prior to buffer overflow; they call this strategy Early Packet Discard. They also discuss general issues of congestion avoidance for best-effort traffic in ATM networks.

  3. Allocating Network Resources by Weight Between TCP Traffics

    Institute of Scientific and Technical Information of China (English)

    xU ChangBiao(徐昌彪); LONG KePing(隆克平); YANG ShiZhong(杨士中)

    2003-01-01

    Under the current TCP/IP architecture, all TCP traffics compete for networkresources completely fairly, which makes it difficult to satisfy applications' versatile communicationrequirements. This paper presents an improved TCP congestion control mechanism where thecongestion window becomes ω(1 - b)W rather than (1 - b)W for every window W containing apacket loss. Theoretical analysis and simulation results show that it can be easily implementedwith less additional overhead and can easily perform network resource allocation by weightedparameter w for traffics under the similar communication environments, which can efficiently leadto guaranteed relative quality of services and improve network performances.

  4. Identifying online traffic based on property of TCP flow

    Institute of Scientific and Technical Information of China (English)

    HONG Min-huo; GU Ren-tao; WANG Hong-xiang; SUN Yong-mei; JI Yue-feng

    2009-01-01

    Classification of network traffic using port-based or payload-based analysis is becoming increasingly difficult when many applications use dynamic port numbers, masquerading techniques, and encryption to avoid detection. In this article, an approach is presented for online traffic classification relying on the observation of the first n packets of a transmission control protocol (TCP) connection. Its key idea is to utilize the properties of the observed first ten packets of a TCP connection and Bayesian network method to build a classifier. This classifier can classify TCP flows dynamically as packets pass through it by deciding whether a TCP flow belongs to a given application. The experimental results show that the proposed approach performs well in online Internet traffic classification and that it is superior to naive Bayesian method.

  5. TCP/IP Communication System for Controlling a Vehicular Traffic Intersection

    Directory of Open Access Journals (Sweden)

    Pedraza-Martínez Luis Fernando

    2013-10-01

    Full Text Available This paper describes the development of a prototype of a vehicular traffic controller, whose system of communication is based on the TCP/IP protocol, in order to re- motely monitor and control the operation of traffic lights for a vehicular intersection. The results show the times of communication between the central and the traffic controller. The conclusions highlight the importance of using the TCP/IP protocol in traffic light systems.

  6. PERFORMANCE ANALYSIS OF ROUTING PROTOCOLS AND TCP VARIANTS UNDER HTTP AND FTP TRAFFIC IN MANETS

    Directory of Open Access Journals (Sweden)

    Ghassan A. QasMarrogy

    2014-12-01

    Full Text Available MANET stands for mobile ad-hoc network that has multi-hop and dynamic nature, where each station changes its location frequently and automatically configures itself. In this paper, four routing protocols that are OLSR, GRP, DSR, and AODV are discussed along with three TCP variants that are SACK, New Reno and Reno. The main focus of this paper is to study the impact scalability, mobility and traffic loads on routing protocols and TCP variants. The paper results shows that the proactive protocols OLSR and GRP outperform the reactive protocols AODV and DSR with the same nodes size, nodes speed, and traffic load. On the other hand, the TCP variants research reveal the superiority of the TCP SACK variant over the other two variants in case of adapting to varying network size, while the TCP Reno variant acts more robustly in varying mobility speeds and traffic loads

  7. TCP TRAFFIC PERFORMANCE IMPROVING IN LTE-A NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Yang Bo; Wu Weimin; Zhu Guangxi; Yu Hongtao

    2013-01-01

    This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems.Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained.Howev5r,those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks.In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed.The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell,as well as reducing radio resources in LTE-A macro cells.

  8. Robust control tools for traffic monitoring in TCP/AQM networks

    CERN Document Server

    Ariba, Yassine; Rahme, Sandy; Labit, Yann

    2009-01-01

    Several studies have considered control theory tools for traffic control in communication networks, as for example the congestion control issue in IP (Internet Protocol) routers. In this paper, we propose to design a linear observer for time-delay systems to address the traffic monitoring issue in TCP/AQM (Transmission Control Protocol/Active Queue Management) networks. Due to several propagation delays and the queueing delay, the set TCP/AQM is modeled as a multiple delayed system of a particular form. Hence, appropriate robust control tools as quadratic separation are adopted to construct a delay dependent observer for TCP flows estimation. Note that, the developed mechanism enables also the anomaly detection issue for a class of DoS (Denial of Service) attacks. At last, simulations via the network simulator NS-2 and an emulation experiment validate the proposed methodology.

  9. Performance analysis of TCP traffic and its influence on ONU's energy saving in energy efficient TDM-PON

    Science.gov (United States)

    Alaelddin, Fuad Yousif Mohammed; Newaz, S. H. Shah; Lee, Joohyung; Uddin, Mohammad Rakib; Lee, Gyu Myoung; Choi, Jun Kyun

    2015-12-01

    The majority of the traffic over the Internet is TCP based, which is very sensitive to packet loss and delay. Existing research efforts in TDM-Passive Optical Networks (TDM-PONs) mostly evaluate energy saving and traffic delay performances under different energy saving solutions. However, to the best of our knowledge, how energy saving mechanisms could affect TCP traffic performance in TDM-PONs has hardly been studied. In this paper, by means of our state-of-art OPNET Modular based TDM-PON simulator, we evaluate TCP traffic delay, throughput, and Optical Network Unit (ONU) energy consumption performances in a TDM-PON where energy saving mechanisms are employed in ONUs. Here, we study the performances under commonly used energy saving mechanisms defined in standards for TDM-PONs: cyclic sleep and doze mode. In cyclic sleep mode, we evaluate the performances under two well-known sleep interval length deciding algorithms (i.e. fixed sleep interval (FSI) and exponential sleep interval deciding (ESID)) that an OLT uses to decide sleep interval lengths for an ONU. Findings in this paper put forward the strong relationship among TCP traffic delay, throughput and ONU energy consumption under different sleep interval lengths. Moreover, we reveal that under high TCP traffic, both FSI and ESID will end up showing similar delay, energy and throughput performance. Our findings also show that doze mode can offer better TCP throughput and delay performance at the price of consuming more energy than cyclic sleep mode. In addition, our results provide a glimpse on understanding at what point doze mode becomes futile in improving energy saving of an ONU under TCP traffic. Furthermore, in this paper, we highlight important research issues that should be studied in future research to maximize energy saving in TDM-PONs while meeting traffic Quality of Service requirements.

  10. Achieving QoS for TCP Traffic in Satellite Networks with Differentiated Services

    Science.gov (United States)

    Durresi, Arjan; Kota, Sastri; Goyal, Mukul; Jain, Raj; Bharani, Venkata

    2001-01-01

    Satellite networks play an indispensable role in providing global Internet access and electronic connectivity. To achieve such a global communications, provisioning of quality of service (QoS) within the advanced satellite systems is the main requirement. One of the key mechanisms of implementing the quality of service is traffic management. Traffic management becomes a crucial factor in the case of satellite network because of the limited availability of their resources. Currently, Internet Protocol (IP) only has minimal traffic management capabilities and provides best effort services. In this paper, we presented a broadband satellite network QoS model and simulated performance results. In particular, we discussed the TCP flow aggregates performance for their good behavior in the presence of competing UDP flow aggregates in the same assured forwarding. We identified several factors that affect the performance in the mixed environments and quantified their effects using a full factorial design of experiment methodology.

  11. STUDY ON NONLINEAR DYNAMICS OF TCP-RENO TRAFFIC UNDER RED

    Institute of Scientific and Technical Information of China (English)

    Wang Li; Li Zengzhi; Xue Ke

    2006-01-01

    A discrete time feedback control system model based on a multi-router network has been presented. The model can be described by a set of recurrence equations. The numerical examples about the bifurcation of average and instantaneous queue size along with the variety of RED control parameter are shown. The simulate experiments about those of the RED control parameters are also presented. All of these results show that instability in TCP-Reno traffic under RED can be induced by the inherent nonlinear behavior of the network.

  12. Performance of TCP with multiple Priority Classes

    NARCIS (Netherlands)

    Vranken, R.; Mei, van der R.D.; Kooij, R.E.; Berg, van den J.L.

    2002-01-01

    We consider the dimensioning problem for Internet access links carrying TCP traffic with two priority classes. To this end, we study the behaviour of TCP at the flow level described by a multiple-server Processor Sharing (PS) queueing model with two customer classes, where the customers represent fl

  13. Experimental Evaluation of Memory Effects on TCP Traffic in Congested Networks

    Directory of Open Access Journals (Sweden)

    Kulvinder Singh

    2010-09-01

    Full Text Available Today the Internet is a worldwide-interconnected computer network that transmits data by packet switching based on the TCP/IP protocol suite. Internet has TCP as the main protocol of the transport layer. The performance of TCP is studied by many researchers. They are trying to analytically characterizing the throughput of TCP's congestion control mechanism. Internet routers were widely believed to need big memory spaces. Commercial routers today have huge packet memory spaces, often storing millions of packets, under the assumption that big memory spaces lead to good statistical multiplexing and hence efficient use of expensive long-haul links. In this paper, we summarize the works and present the experimental study result with big memory space size and give a qualitative analysis of the result. Our conclusion is that the, round-trip time (RTT is not increased by linear, but by quadric when the memory space size of the bottleneck is big enough. Our goal is to estimate the average queue length of the memory space size and develop a TCP model based on RTT and the average queue length.

  14. Design Issues for Traffic Management for the ATM UBR + Service for TCP Over Satellite Networks

    Science.gov (United States)

    Jain, Raj

    1999-01-01

    This project was a comprehensive research program for developing techniques for improving the performance of Internet protocols over Asynchronous Transfer Mode (ATM) based satellite networks. Among the service categories provided by ATM networks, the most commonly used category for data traffic is the unspecified bit rate (UBR) service. UBR allows sources to send data into the network without any feedback control. The project resulted in the numerous ATM Forum contributions and papers.

  15. STUDY ON NONLINEAR DYNAMICS OF TCP-RENO TRAFFIC UNDER RED

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The traditional net work management can tmeet the users requirements about quality of servicealong with the fast increasing of the scale of net-work.So service management has been proposed toguarantee the QoS of net work services and has beena hot topic in the research community for a fewyears now,and a lot of research has been carriedout[1-6].The net work traffic management is one ofthe key compositions of service management,andplays ani mportant role inthe QoS,congestion con-trol and net work design.The s...

  16. Carry

    DEFF Research Database (Denmark)

    Koijen, Ralph S.J.; Moskowitz, Tobias J.; Heje Pedersen, Lasse;

    that include global equities, global bonds, currencies, commodities, US Treasuries, credit, and equity index options. This predictability underlies the strong returns to "carry trades" that go long high-carry and short low-carry securities, applied almost exclusively to currencies, but shown here...

  17. TCP-Rab:a receiver advertisement based TCP protocol

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    With the evolution of network technologies,the deficiencies of TCP protocol are becoming more and more distinct. The new TCP implementation,called Receiver Advertisement Based TCP(TCP-Rab)proposed here to eliminate these deficiencies,adopts two basic mechanisms:(1)Bandwidth Estimation and(2)Immediate Recovery. Bandwidth estimation is carried out at the receiver,and the result is sent back to the sender via the acknowledgments. Immediate Recovery guarantees high performance even in lossy link. Rab can distinguish the reason for packet loss,and thus adopt appropriate recovery strategy. For loss by network congestion,it will back off its congestion window,and for loss by link errors,it will recover the congestion window immediately. Simulations indicated that Rah has superiority over other TCP implementations.

  18. TCP-Rab: a receiver advertisement based TCP protocol

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    With the evolution of network technologies, the deficiencies of TCP protocol are becoming more and more distinct. The new TCP implementation, called Receiver Advertisement Based TCP (TCP-Rab) proposed here to eliminate these deficiencies, adopts two basic mechanisms: (1) Bandwidth Estimation and (2) Immediate Recovery. Bandwidth estimation is carried out at the receiver, and the result is sent back to the sender via the acknowledgments. Immediate Recovery guarantees high performance even in lossy link. Rab can distinguish the reason for packet loss, and thus adopt appropriate recovery strategy. For loss by network congestion, it will back off its congestion window, and for loss by link errors, it will recover the congestion window immediately. Simulations indicated that Rab has superiority over other TCP implementations.

  19. Long-Haul TCP vs. Cascaded TCP

    OpenAIRE

    Feng, Wu-chun

    2006-01-01

    In this work, we investigate the bandwidth and transfer time of long-haul TCP versus cascaded TCP [5]. First, we discuss the models for TCP throughput. For TCP flows in support of bulk data transfer (i.e., long-lived TCP flows), the TCP throughput models have been derived [2, 3]. These models rely on the congestion-avoidance algorithm of TCP. Though these models cannot be applied with short-lived TCP connections, our interest relative to logistical networking is in longer-li...

  20. On the Effective Evaluation of TCP

    Science.gov (United States)

    Allman, Mark; Falk, Aaron

    2000-01-01

    Understanding the performance of the Internet's Transmission Control Protocol (TCP) is important because it is the dominant protocol used in the Internet today. Various testing methods exist to evaluate TCP performance, however all have pitfalls an that need to be understood prior to obtaining useful results. Simulating TCP is difficult because of the wide range of variables, environments, and implementations available. Testing TCP modifications in the global Internet may not be the answer either: testing new protocols on real networks endangers other people's traffic and, if not done correctly, may also yield inaccurate or misleading results. In order for TCP research to be independently evaluated in the Internet research community there is a set of questions that researchers should try to answer. This paper attempts to list some of those questions and make recommendations as to how TCP testing can be structured to be provide useful answers.

  1. TCP HolyWood

    OpenAIRE

    Oscar Núñez Mori

    2005-01-01

    We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard. Apresentamos um novo Protocolo de Controle de...

  2. THE FAILURE OF TCP IN HIGH-PERFORMANCE COMPUTATIONAL GRIDS

    Energy Technology Data Exchange (ETDEWEB)

    W. FENG; ET AL

    2000-08-01

    Distributed computational grids depend on TCP to ensure reliable end-to-end communication between nodes across the wide-area network (WAN). Unfortunately, TCP performance can be abysmal even when buffers on the end hosts are manually optimized. Recent studies blame the self-similar nature of aggregate network traffic for TCP's poor performance because such traffic is not readily amenable to statistical multiplexing in the Internet, and hence computational grids. In this paper we identify a source of self-similarity previously ignored, a source that is readily controllable--TCP. Via an experimental study, we examine the effects of the TCP stack on network traffic using different implementations of TCP. We show that even when aggregate application traffic ought to smooth out as more applications' traffic are multiplexed, TCP induces burstiness into the aggregate traffic loud, thus adversely impacting network performance. Furthermore, our results indicate that TCP performance will worsen as WAN speeds continue to increase.

  3. Historical and Contemporary Aspects of the Market for the Cargo Traffic carried on the Romanian Ports

    Directory of Open Access Journals (Sweden)

    Florin-Dan Puşcaciu

    2014-05-01

    Full Text Available We hereby try to approach some aspects about the port traffic, analyzing this activity from the marketing point of view, on the one side, and looking at the ports as entities which represented real emblems, symbols of economic and social development, cities like Galaţi, Brăila, Tulcea, being zones which were wholly identified with the port activity, on the other side. This analysis is necessary in the context of the favorable geographical placement of Romania, which benefits both of the Danube river road, and also the Black Sea. Despite of all these historical and geographic aspects, and also of some directions of developing the commercial Romanian fleet in the past period, the Danube ports are going on a regress stage. In order to catch the now on quantitative and qualitative changes over which are on this market, we consider necessary an incursion in the inter-war period, basing both on the tradition of these maritime and river ports, and on the assertion of Joseph Schumpeter as per which the economic aspects can be studied by history, theory and statistics. The conclusion of the study points to that the port activities estimated by the tonnage shipped in these sea-Danube ports regressed, and the Romanian fleet is now almost absent, non-existent. We firmly underline the necessity of a national strategy in this field.

  4. Investigation on TCP/IP Congestion Control in Optical Burst Switched (OBS Network

    Directory of Open Access Journals (Sweden)

    Ms. Payal Daryani

    2012-03-01

    Full Text Available Transport Control Protocol (TCP is the dominant protocol in modern communication networks, in which the issues of reliability, flow, and congestion control must be handled efficiently. In this review paper an analytical switching is used to exploit the huge bandwidth of optical fibers for future high speed internet backbone. It carries multiple packets, in their turn. Different aggregation schemes have been considered and evaluated.TCP performance greatly depends on the TCP congestion window behavior that is related to loss events occurring in the optical burst switched network, there is a special term called traffic shaping by which we control over the network according to the network load .that means we increase or decrease the send rate according to the network demand.

  5. Known TCP Implementation Problems

    Science.gov (United States)

    Paxson, Vern (Editor); Allman, Mark; Dawson, Scott; Fenner, William; Griner, Jim; Heavens, Ian; Lahey, K.; Semke, J.; Volz, B.

    1999-01-01

    This memo catalogs a number of known TCP implementation problems. The goal in doing so is to improve conditions in the existing Internet by enhancing the quality of current TCP/IP implementations. It is hoped that both performance and correctness issues can be resolved by making implementors aware of the problems and their solutions. In the long term, it is hoped that this will provide a reduction in unnecessary traffic on the network, the rate of connection failures due to protocol errors, and load on network servers due to time spent processing both unsuccessful connections and retransmitted data. This will help to ensure the stability of the global Internet. Each problem is defined as follows: Name of Problem The name associated with the problem. In this memo, the name is given as a subsection heading. Classification one or more problem categories for which the problem is classified: "congestion control", "performance", "reliability", "resource management". Description A definition of the problem, succinct but including necessary background material. Significance A brief summary of the sorts of environments for which the problem is significant.

  6. A Forager Bee’s Intelligence Inspired Dynamic Queue Scheduling for the Internet Traffic

    Directory of Open Access Journals (Sweden)

    M. A. Bhagyaveni

    2012-01-01

    Full Text Available Problem statement: In the present evolution of large scale internet communication, per flow control scheme faces scalability issue due to tremendous number of flows. The aggregation based approaches such as differentiated architecture relieve the storage of state of flows in core router. TCP is the dominating protocol that carries majority of the total internet traffic. Recent internet traffic measurement shows most of the TCP flows are short lived. The performance improvement in the internet traffic can be achieved by the advantages of scheduling algorithms to favor short TCP flows first However long TCP flows competing against short TCP flows starve at some point. Approach: In this study we propose aggregation based scheduling algorithm namely Guaranteed Dynamic Queue Scheduling (G-DQS that estimates the available bandwidth of the network using the forager bee’s intelligence for providing guaranteed throughput. In addition, G-DQS algorithm is proposed to favor the short TCP flows without penalizing the performance of long flows using dynamic scheduling ratio. Results: Simulation of the proposed scheduling method show that mean transmission time of flows and packet loss significantly decrease in comparison with FIFO and RuN2C. Conclusion: Proposed forager bee’s intelligence inspired scheduling approach achieves the guaranteed throughput in the large scale network.

  7. Analysis and Improvement of TCP Congestion Control Mechanism Based on Global Optimization Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Network flow control is formulated as a global optimization problem of user profit. A general global optimization flow control model is established. This model combined with the stochastic model of TCP is used to study the global rate allocation characteristic of TCP. Analysis shows when active queue manage ment is used in network TCP rates tend to be allocated to maximize the aggregate of a user utility function Us (called Us fairness). The TCP throughput formula is derived. An improved TCP congestion control mecha nism is proposed. Simulations show its throughput is TCP friendly when competing with existing TCP and its rate change is smoother. Therefore, it is suitable to carry multimedia applications.

  8. Characterizing End-to-End Delay Performance of Randomized TCP Using an Analytical Model

    Directory of Open Access Journals (Sweden)

    Mohammad Shorfuzzaman

    2016-03-01

    Full Text Available TCP (Transmission Control Protocol is the main transport protocol used in high speed network. In the OSI Model, TCP exists in the Transport Layer and it serves as a connection-oriented protocol which performs handshaking to create a connection. In addition, TCP provides end-to-end reliability. There are different standard variants of TCP (e.g. TCP Reno, TCP NewReno etc.which implement mechanisms to dynamically control the size of congestion window but they do not have any control on the sending time of successive packets. TCP pacing introduces the concept of controlling the packet sending time at TCP sources to reduce packet loss in a bursty traffic network. Randomized TCP is a new TCP pacing scheme which has shown better performance (considering throughput, fairness over other TCP variants in bursty networks. The end-to-end delay of Randomized TCP is a very important performance measure which has not yet been addressed. In the current high speed networks, it is increasingly important to have mechanisms that keep end-to-end to delay within an acceptable range. In this paper, we present the performance evaluation of end-to-end delay of Randomized TCP. To this end, we have used an analytical and a simulation model to characterize the end-to-end delay performance of Randomized TCP.

  9. TCP Pacing Developed

    Science.gov (United States)

    Ivancic, William D.

    2002-01-01

    Transmission control protocol (TCP) was conceived and designed to run over a variety of communication links, including wireless and high-bandwidth links. However, with recent technological advances in satellite and fiber-optic networks, researchers are reevaluating the flexibility of TCP. The TCP pacing and packet pair probing implementation may help overcome two of the major obstacles identified for efficient bandwidth utilization over communication links with large delay-bandwidth products.

  10. A simulation-based study of HighSpeed TCP and its deployment

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Evandro de [Univ. of California, Berkeley, CA (United States)

    2003-05-01

    The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP's congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions including different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.

  11. A simulation-based study of HighSpeed TCP and its deployment

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Evandro de

    2003-04-29

    The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP's congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions including different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.

  12. A comparative study of aggregate TCP retransmission rates

    CERN Document Server

    Pentikousis, Kostas; Andrade, Asha; 10.2316/Journal.202.2010.4.202-2660

    2011-01-01

    Segment retransmissions are an essential tool in assuring reliable end-to-end communication in the Internet. Their crucial role in TCP design and operation has been studied extensively, in particular with respect to identifying non-conformant, buggy, or underperforming behaviour. However, TCP segment retransmissions are often overlooked when examining and analyzing large traffic traces. In fact, some have come to believe that retransmissions are a rare oddity, characteristically associated with faulty network paths, which, typically, tend to disappear as networking technology advances and link capacities grow. We find that this may be far from the reality experienced by TCP flows. We quantify aggregate TCP segment retransmission rates using publicly available network traces from six passive monitoring points attached to the egress gateways at large sites. In virtually half of the traces examined we observed aggregate TCP retransmission rates exceeding 1%, and of these, about half again had retransmission rate...

  13. TCP throughput adaptation in WiMax networks using replicator dynamics.

    Science.gov (United States)

    Anastasopoulos, Markos P; Petraki, Dionysia K; Kannan, Rajgopal; Vasilakos, Athanasios V

    2010-06-01

    The high-frequency segment (10-66 GHz) of the IEEE 802.16 standard seems promising for the implementation of wireless backhaul networks carrying large volumes of Internet traffic. In contrast to wireline backbone networks, where channel errors seldom occur, the TCP protocol in IEEE 802.16 Worldwide Interoperability for Microwave Access networks is conditioned exclusively by wireless channel impairments rather than by congestion. This renders a cross-layer design approach between the transport and physical layers more appropriate during fading periods. In this paper, an adaptive coding and modulation (ACM) scheme for TCP throughput maximization is presented. In the current approach, Internet traffic is modulated and coded employing an adaptive scheme that is mathematically equivalent to the replicator dynamics model. The stability of the proposed ACM scheme is proven, and the dependence of the speed of convergence on various physical-layer parameters is investigated. It is also shown that convergence to the strategy that maximizes TCP throughput may be further accelerated by increasing the amount of information from the physical layer.

  14. Study on Early Warning of Traffic Resources and Environment Carrying Capacity%交通资源环境承载力预警研究

    Institute of Scientific and Technical Information of China (English)

    蒋恵园; 黄永燊

    2015-01-01

    新常态下快速发展的综合交通运输对资源环境的胁迫作用日益明显,资源环境对交通运输的承载能力成为地区健康发展的重要衡量标准。在界定交通资源环境承载力概念的基础上,从资源承载力和生态环境承载力两个方面构建交通资源环境承载力指标体系。结合可拓学的模糊物元理论和信息论的熵理论,建立基于模糊物元的交通资源环境承载力的预警模型,并对长江经济带七省二市的交通资源环境承载力进行预警研究。实例结果表明,构建的交通资源环境承载力指标体系基本合理,模糊物元预警模型在资源环境承载力的预警研究中具有较强的适用性和可操作性。%The rapid development of integrated transportation in the new normal poses an increasing threat to environment and resources. The bearing capacity of environment and resources to transportation becomes a significant criterion to measure whether an area is developing healthily. Based on the definition of traffic resource environmental bearing capacity, a traffic resource and environmental bearing capacity index system is built from both resources carrying capacity and environmental carrying capacity aspects. Through combining fuzzy matter-element theory of extension theory with entropy theory, an early-warning model of traffic resource and environmental bearing capacity is established, this model is applied to study the traffic resources and environmental carrying capacity of Yangtze River economic belt (include seven provinces and two municipalities as well). The results demonstrate that:The traffic resources and environmental carrying capacity index system is reasonable and the fuzzy matter-element model used in studying the early-warning of resources environmental bearing capacity is of sound applicability and operability.

  15. Traffic forecaster for MPLS multimedia data streams

    Science.gov (United States)

    Ambrose, Barry; Lin, Freddie

    2006-05-01

    Contemporary high performance data networks carry a wide range of multimedia services (voice, video, audio, text, sensor data, etc.) that require an outstanding Quality of Service (QoS) to provide performance guarantees in priority delivery, latency, bandwidth utilization, load balancing, etc. With the advent of recent Multi-Protocol Label Switching (MPLS) network standards, the QoS has made significant progress in performance to provide these performance guarantees. Right now, attention has turned to the task of managing these QoS networks more efficiently through the handling of network traffic. We have investigated a novel Network Traffic Forecasting Assisted QoS Planner technology that will provide constantly updated forecasts of data traffic and server loads to any application that needs this information. Using source models of voice, video and data traffic based on empirical studies of TCP/IP data traffic carried out by Paxson and Floyd in the 1990's, our studies have shown that the system may provide up to 43% bandwidth savings for MPLS data streams, by predicting future traffic flows and reserving network resources to accommodate the predicted traffic. The system additionally provides a means to submit bandwidth reservation requests for those applications that need assured service guarantees for data delivery. The technology essentially increases the efficiency and effectiveness of multimedia information and communication network infrastructure that supports multiple or adaptive QoS levels for multimedia data networking and information system applications.

  16. Performance of TCP-Throughput on NS2 by Using Different Simulation Parameters

    Directory of Open Access Journals (Sweden)

    Dr. Neeraj Bhargava , Dr. Ritu Bhargava, Anchal Kumawat , Bharat Kumar

    2012-12-01

    Full Text Available ns2 is a discrete event simulator for networkingresearch, which works at the packet level. Here, wewill be using ns2 to simulate traffic congestion ofTCP and UDP packets inside a network. ns2 ispopularly used in the simulation of routing andmulticast protocols and is heavily used in ad-hocnetworking research. ns2 supports networkprotocols (TCP, UDP, HTTP, Routing algorithms,MAC etc. for offering simulation results for wiredand wireless networks. When using TCP to transferdata the two most important factors are the TCPwindow size and the round trip latency. This paperdeals the effect that the size of the flow controlwindow has on the throughput of a TCP connectionby using simulation parameters like-packet delay(sec, bandwidth, file-size (bytes and to implementnetwork fed with TCP traffic and backgroundtraffic. The objective of this paper is to observe theperformance of TCP

  17. Bits of Internet traffic control

    OpenAIRE

    Vojnovic, Milan; Le Boudec, Jean Yves

    2005-01-01

    In this work, we consider four problems in the context of Internet traffic control. The first problem is to understand when and why a sender that implements an equation-based rate control would be TCP-friendly, or not—a sender is said to be TCP-friendly if, under the same operating conditions, its long-term average send rate does not exceed that of a TCP sender. It is an established axiom that some senders in the Internet would need to be TCP-friendly. An equation-based rate control sender pl...

  18. Bits of Internet Traffic Control

    OpenAIRE

    Vojnovic, Milan

    2003-01-01

    In this work, we consider four problems in the context of Internet traffic control. The first problem is to understand when and why a sender that implements an equation-based rate control would be TCP-friendly, or not—a sender is said to be TCP-friendly if, under the same operating conditions, its long-term average send rate does not exceed that of a TCP sender. It is an established axiom that some senders in the Internet would need to be TCP-friendly. An equation-based rate control sender pl...

  19. Analysis of TCP performance in data center networks

    CERN Document Server

    Kulkarni, Santosh

    2014-01-01

    This book addresses the need to improve TCP’s performance inside data centers by providing solutions that are both practical and backward compatible with standard TCP versions. The authors approach this challenge first by deriving an analytical model for TCP’s performance under typical data center workload traffic.  They then discuss some solutions that are designed to improve TCP performance by either proactively detecting network congestion through probabilistic retransmission or by avoiding timeout penalty through dynamic resizing of TCP segments. Experimental results show that each of techniques discussed outperforms standard TCP inside a data center.  ·         Analyzes the reasons behind TCP performance slump inside data centers when operating under synchronized workload traffic; ·         Introduces solutions to TCP performance slump inside data centers that are both practical and backward compatible; ·         Describes mechanisms that are responsible for TCP’s relia...

  20. Performance Analysis of Different MANET Specific TCP variants

    Directory of Open Access Journals (Sweden)

    Debajyoti Pal

    2012-09-01

    Full Text Available - Transmission Control Protocol(TCP is implemented in the transport layer of a MANET, which enjoys the advantage of reliable data transmission over the Internet. However, due to certain unique characteristics of a MANET, modification of classical TCP has been done so as to improve its performance in such an environment. Accordingly, several MANET specific TCP versions like TCP Reno, TCP New Reno, TCP Tahoe and TCP Vegas have come into prominence. This paper evaluates the performance of the different TCP versions for the same network topology over certain fixed parameters like number of packets generated/node, average packet loss, average delay incurred by the packets while in transit from source to destination and the processing time taken by the intermediate nodes. For routing purpose, we have assumed Ad-HocOn Demand Distance Vector Routing (AODV as the standard. To address the common issues of congestion control as with TCP, the experiment has been carried out under different network loading conditions that have been achieved by slowly increasing the node density.

  1. Improving TCP Network Performance by Detecting and Reacting to Packet Reordering

    Science.gov (United States)

    Kruse, Hans; Ostermann, Shawn; Allman, Mark

    2003-01-01

    There are many factors governing the performance of TCP-basec applications traversing satellite channels. The end-to-end performance of TCP is known to be degraded by the reordering, delay, noise and asymmetry inherent in geosynchronous systems. This result has been largely based on experiments that evaluate the performance of TCP in single flow tests. While single flow tests are useful for deriving information on the theoretical behavior of TCP and allow for easy diagnosis of problems they do not represent a broad range of realistic situations and therefore cannot be used to authoritatively comment on performance issues. The experiments discussed in this report test TCP s performance in a more dynamic environment with competing traffic flows from hundreds of TCP connections running simultaneously across the satellite channel. Another aspect we investigate is TCP's reaction to bit errors on satellite channels. TCP interprets loss as a sign of network congestion. This causes TCP to reduce its transmission rate leading to reduced performance when loss is due to corruption. We allowed the bit error rate on our satellite channel to vary widely and tested the performance of TCP as a function of these bit error rates. Our results show that the average performance of TCP on satellite channels is good even under conditions of loss as high as bit error rates of 10(exp -5)

  2. TCP/IP Security%TCP/IP协议安全

    Institute of Scientific and Technical Information of China (English)

    张少中; 唐毅谦; 赵悦; 聂铁铸; 刘丽华

    2000-01-01

    TCP/IP协议是Internet上网络互连的基础,TCP/IP 协议的安全直接关系到网络和系统的安全.本文通过分析TCP/IP的工作机制,讨论了网络入侵的基本途径,并阐述了一些改进和提高TCP/IP协议安全性的方法.

  3. Improving the Performance of Interactive TCP Applications using End-point Based and Network Level Techniques

    Directory of Open Access Journals (Sweden)

    Varun G Menon

    2012-04-01

    Full Text Available Recent measurement based studies reveal that most of the Internet connections are short in terms of the amount of traffic they carry, while a small fraction of the connections are carrying a largeportion of the traffic.. Most of these short flows are from interactive applications like telnet, gaming that use TCP protocol for connection establishment and data transfer. These short TCP flows suffer from severe response-time performance degradations when multiplexed with long-lived flows during times of network congestion. The reasons for this problem is that, in the absence of large number of packets the short flows are unable to get a detailed knowledge about the level of underlying network congestion and even a single packet loss forces long retransmission timeouts. Also as the numbers of packets are less they are not able to develop large congestion windows and thus unable to jumpstart the next data burst. Due to this, clients of interactive applications suffer from increased response time for data packets sent and they try to upgrade their short flows to long flows by sending dummy packets into the network even when they do not have any data to send. This behavior can lead to severe congestion in the network and causes harm to statistical multiplexing in the Internet. This paper aims at providing easy to implement techniques that can be used by the clients of interactive applications to get much better performance without causing any serious congestion in the network.

  4. Energy Efficient TCP

    NARCIS (Netherlands)

    Donckers, L.; Smit, G.J.M.; Smit, L.T.

    2002-01-01

    This paper describes the design of an energy-efficient transport protocol for mobile wireless communication. First we describe the metrics used to measure the energy efficiency of transport protocols. We identify several problem areas that prevent TCP/IP from reaching high levels of energy efficienc

  5. A Throughput Analysis of TCP in ADHOC Networks

    Directory of Open Access Journals (Sweden)

    S.P.Valli

    2013-07-01

    Full Text Available Transmission Control Protocol (TCP is a connection oriented end-end reliable byte stream transport layer protocol. It is widely used in the Internet.TCP is fine tuned to perform well in wired networks. However the performance degrades in mobile ad hoc networks. This is due to the characteristics specific to wireless networks, such as signal fading, mobility, unavailability of routes. This leads to loss of packets which may arise either from congestion or due to other non-congestion events. However TCP assumes every lo ss as loss due to congestion and invokes the congestion control procedures. TCP reduces cong estion window in response, causing unne- cessary degradation in throughput. In mobile ad hoc networks multi-hop path forwarding fur- ther worsens the packet loss and throughput. To und erstand the TCP behavior and improve the TCP performance over mobile ad hoc networks conside rable research has been carried out. As the research is still active in this area a compreh ensive and in-depth study on the TCP through- put and the various parameters that degrade the per formance of TCP have been analyzed. The analysis is done using simulations in Qualnet 5.0

  6. Performance Improvement of TCP by TCP Reno and SACK Acknowledgement

    Directory of Open Access Journals (Sweden)

    Mrs. Reena Rai

    2012-03-01

    Full Text Available Transmission Control Protocol (TCP is the dominating end-to-end transport layer protocol which provides secure and reliable data transfer together with some other protocols. In this review paper, we contend that existing approaches to improve TCP performance over mobile ad-hoc networks have focused only on a subset of the factors affecting TCP performance by TCP Reno, SACK and Vegas. Effective resource utilization, such as bandwidth utilization, retransmission rate and window size, is compared. for evaluate these TCP congestion control algorithms from many aspects are present and We also concern fair resource allocation from two main categories, one is fairness between different delay links, and the other is competition between different TCP congestion control algorithms

  7. Research on TCP/IP computer network congestion control%对TCP/IP计算机网络拥塞控制的研究

    Institute of Scientific and Technical Information of China (English)

    余学杰

    2014-01-01

    为提升计算机的网络性能,更好地避免拥塞现象的发生,需要对其进行必要的技术控制。鉴于此,对基于TCP/IP协议的网络拥塞控制方法进行分析。在TCP拥塞控制中主要采用TCP Tahoe,TCP Reno,TCP New Reno以及TCP Sack四种方法,其中TCP New Reno对快速恢复算法进行了改进,通过对TCP协议中的Reno进行可视化处理,实行对网络拥塞的有效管理。而IP拥塞控制方法则分为FIFO,FQ和WFQ,RED以及ECN四种类型,通过队列调度管理方式实现了对网络拥塞的有效管理。%To enhance the performance of the computer network and avoid the occurrence of the congestion phenomenon,it is necessary to carry out the effective technical control. In view of this,the network congestion control methods based on TCP/IP protocol are analyzed. Four methods of TCP Tahoe,TCP Reno,TCP New Reno and TCP Sack are used for TCP congestion control;in which fast recovery algorithm was improved by means of TCP New Reno. The visualization processing can be per-formed through the Reno in TCP protocol to implement the effective management of network congestion. The IP congestion con-trol method can be divided into FIFO,FQ/WFQ,RED and ECN to realize the effective management of network congestion by queue scheduling management pattern.

  8. The Tcp conjugation system of Clostridium perfringens.

    Science.gov (United States)

    Wisniewski, Jessica A; Rood, Julian I

    2017-03-07

    The Gram-positive pathogen Clostridium perfringens possesses a family of large conjugative plasmids that is typified by the tetracycline resistance plasmid pCW3. Since these plasmids may carry antibiotic resistance genes or genes encoding extracellular or sporulation-associated toxins, the conjugative transfer of these plasmids appears to be important for the epidemiology of C. perfringens-mediated diseases. Sequence analysis of members of this plasmid family identified a highly conserved 35kb region that encodes proteins with various functions, including plasmid replication and partitioning. The tcp conjugation locus also was identified in this region, initially based on low-level amino acid sequence identity to conjugation proteins from the integrative conjugative element Tn916. Genetic studies confirmed that the tcp locus is required for conjugative transfer and combined with biochemical and structural analyses have led to the development of a functional model of the Tcp conjugation apparatus. This review summarises our current understanding of the Tcp conjugation system, which is now one of the best-characterized conjugation systems in Gram-positive bacteria.

  9. TCP-ADaLR: TCP with adaptive delay and loss response for broadband GEO satellite networks

    OpenAIRE

    Omueti, Modupe Omogbohun

    2007-01-01

    Transmission Control Protocol (TCP) performance degrades in broadband geostationary satellite networks due to long propagation delays and high bit error rates. In this thesis, we propose TCP with algorithm modifications for adaptive delay and loss response (TCP-ADaLR) to improve TCP performance. TCP-ADaLR incorporates delayed acknowledgement mechanism recommended for Internet hosts. We evaluate and compare the performance of TCP-ADaLR, TCP SACK, and TCP NewReno, with and without delayed ackno...

  10. High-Speed TCP Testing

    Science.gov (United States)

    Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.

    1999-01-01

    Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.

  11. CW-HSTCP: Fair TCP in high-speed networks

    Institute of Scientific and Technical Information of China (English)

    PAN Xue-zeng; SU Fan-jun; L(U) Yong; PING Ling-di

    2006-01-01

    The congestion control mechanisms of the current standard TCP constrain the congestion windows that can be achieved by TCP in high-speed networks, which leads to low link utilization. HSTCP is one solution to solve this problem by modifying the congestion control mechanism to have the characteristics of TCP friendliness in high loss rate environment and high scalability in low loss rate environment. However, experiments revealed that HSTCP has severe RTT unfairness. After analyzing the RTT unfairness in HSTCP with a model, we proposed CW-HSTCP, which added a fair factor to decrease the difference of congestion window caused by different RTT. Fair factor of long RTT flows can cause a sharp window increment that is easy to cause a bursty traffic, so a method called block-pacing was adopted. Simulation results showed that our new proposal could alleviate the RTT unfairness while keeping advantages of HSTCP.

  12. TCP/IP foundations

    CERN Document Server

    Blank, Andrew G

    2006-01-01

    The world of IT is always evolving, but in every area there are stable, core concepts that anyone just setting out needed to know last year, needs to know this year, and will still need to know next year. The purpose of the Foundations series is to identify these concepts and present them in a way that gives you the strongest possible starting point, no matter what your endeavor. TCP/IP Foundations provides essential knowledge about the two protocols that form the basis for the Internet, as well as many other networks. What you learn here will benefit you in the short term, as you acquire and

  13. Estimating Bottleneck Bandwidth using TCP

    Science.gov (United States)

    Allman, Mark

    1998-01-01

    Various issues associated with estimating bottleneck bandwidth using TCP are presented in viewgraph form. Specific topics include: 1) Why TCP is wanted to estimate the bottleneck bandwidth; 2) Setting ssthresh to an appropriate value to reduce loss; 3) Possible packet-pair solutions; and 4) Preliminary results: ACTS and the Internet.

  14. Improving Throughput For TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    LIU Gang; ZHANG De-yun; LIU Jing; DING Hui-ning

    2004-01-01

    To slove the problem that the implementation of Transmission Control Protocol (TCP) Vegas does not consider the impact of TCP's segment size on Round-Trip Time (RTT) while calculating RTT and the smallest RTT (base_rtt), this paper proposes a modified congestion control mechanism for TCP Vegas. It first groups segments on the basis of segments size and updates base_rtt based on groups. In congestion avoidance phase, TCP Vegas changes its window size according to the measured RTT of the segment corresponding to the latest received ACK and the base_rtt retrieved from the group that the segment belongs to. Simulations illustrate that the enhanced TCP Vegas can achieve higher throughput up to 40 percent.

  15. PERFORMANCE ANALYSIS OF MULTI-PATH TCP NETWORK

    Directory of Open Access Journals (Sweden)

    Hamzah M A Hijawi

    2016-03-01

    Full Text Available MPTCP is proposed by IETF working group, it allows a single TCP stream to be split across multiple paths. It has obvious benefits in performance and reliability. MPTCP has implemented in Linux-based distributions that can be compiled and installed to be used for both real and experimental scenarios. In this article, we provide performance analyses for MPTCP with a laptop connected to WiFi access point and 3G cellular network at the same time. We prove experimentally that MPTCP outperforms regular TCP for WiFi or 3G interfaces. We also compare four types of congestion control algorithms for MPTCP that are also implemented in the Linux Kernel. Results show that Alias Linked Increase Congestion Control algorithm outperforms the others in the normal traffic load while Balanced Linked Adaptation algorithm outperforms the rest when the paths are shared with heavy traffic, which is not supported by MPTCP.

  16. Optimizing TCP Performance over UMTS with Split TCP Proxy

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    Abstract: The TCP performance over UMTS network is challenged by the large delay bandwidth product. Large delay bandwidth product is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer which are used to cope with radio transmission errors....... To cope with large delay bandwidth product, we propose a novel concept of split TCP proxy which is placed at GGSN between UNITS network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products which can...

  17. Consistency Analysis of Network Traffic Repositories

    NARCIS (Netherlands)

    Lastdrager, Elmer; Pras, Aiko

    2009-01-01

    Traffic repositories with TCP/IP header information are very important for network analysis. Researchers often assume that such repositories reliably represent all traffic that has been flowing over the network; little thoughts are made regarding the consistency of these repositories. Still, for var

  18. Introduction à TCP/IP

    OpenAIRE

    Archimbaud, Jean-Luc

    1993-01-01

    • Ce qu'il faut savoir sur les réseaux • Ce qu'il faut savoir sur Ethernet • Généralités sur TCP/IP • IP et consort • TCP et consort • Le routage • Interconnexion de réseaux Ethernet et IP • Nommage • Exemples d'applications • Enchaînement des opérations • Daemons et commandes Unix • Glossaire; Engineering school; Cours d'introduction à TCP/IP

  19. Modelica-based TCP simulation

    Science.gov (United States)

    Velieva, T. R.; Eferina, E. G.; Korolkova, A. V.; Kulyabov, D. S.; Sevastianov, L. A.

    2017-01-01

    For the study and verification of our mathematical model of telecommunication systems a discrete simulation model and a continuous analytical model were developed. However, for various reasons, these implementations are not entirely satisfactory. It is necessary to develop a more adequate simulation model, possibly using a different modeling paradigm. In order to modeling of the TCP source it is proposed to use a hybrid (continuous-discrete) approach. For computer implementation of the model the physical modeling language Modelica is used. The hybrid approach allows us to take into account the transitions between different states in the continuous model of the TCP protocol. The considered approach allowed to obtain a simple simulation model of TCP source. This model has great potential for expansion. It is possible to implement different types of TCP.

  20. Fixing Two BSD TCP Bugs

    Science.gov (United States)

    Allman, Mark

    1997-01-01

    This note outlines two bugs found in the BSD 4.4 Lite TCP implementation, as well as the implications of these bugs and possible ways to correct them. The first problem encountered in this particular TCP implementation is the use of a 2 segment initial congestion window, rather than the standard 1 segment initial window. The second problem is that the receiver delays ACKs in violation of the delayed ACK rules,

  1. Experimental evaluation of TCP protocols for high-speed networks

    OpenAIRE

    Li, Yee-Ting; Leith, Douglas J.; Shorten, Robert N.

    2007-01-01

    In this paper, we present experimental results evaluating the performance of the scalable-TCP, HS-TCP, BIC-TCP, FAST-TCP, and H-TCP proposals in a series of benchmark tests. In summary, we find that both Scalable-TCP and FAST-TCP consistently exhibit substantial unfairness, even when competing flows share identical network path characteristics. Scalable-TCP, HS-TCP, FAST-TCP, and BIC-TCP all exhibit much greater RTT unfairness than does standard TCP, to the extent that long RTT flows ma...

  2. 针对跑道侵入开展空管系统抵御%Against the runway intrusion to carry out air traffic control system to resist

    Institute of Scientific and Technical Information of China (English)

    赵阳

    2015-01-01

    Along with the prosperity and development of the social economy,air traffic was also people make full use of and global civil aviation transportation is more and more frequent,resulting in airport ground traffic becomes congested.The runway incursion is becoming increasingly serious,the slightest mistake will cause the plane crash tragedy.This paper introduces the definition and types of the intrusion runway, analyzes the reasons of the intrusion of the runway,and puts forward the technology leading of the air traffic control system to prevent runway intrusion and improve the safety operation level of airport runway..%随着社会经济的繁荣发展,空中交通也被人们充分地利用,全球民航业的运输交通也越来越频繁,造成机场的地面交通也随之拥挤不堪。跑道侵入的现象日益严重,稍有不慎就会会造成机毁人亡的悲剧。本文介绍侵入跑道的定义及种类,分析侵入跑道产生的原因,提出空管系统对预防跑道侵入的技术主导,改善机场跑道的安全运行水平。

  3. An Empirical Study on variants of TCP over AODV routing protocol in MANET

    CERN Document Server

    Morshed, Md Monzur; Islam, Md Rafiqul

    2011-01-01

    The cardinal concept of TCP development was to carry data within the network where network congestion plays a vital role to cause packet loss. On the other hand, there are several other reasons to lose packets in Mobile Ad Hoc Networks due to fading, interfaces, multi-path routing, malicious node, and black hole. Along with throughput, fairness of TCP protocols is important to establish a good communication. In this paper, an empirical study has been done by simulation and analysis of TCP variations under AODV routing protocol. In our simulation, we studied multiple variations of TCP, such as Reno, New-Reno, Vegas, and Tahoe. The simulation work has been done in NS2 environment. Based on the analysis simulation result of we carried out our observations with respect to the behavior of AODV routing protocol for different TCP packets under several QoS metrics such as drop, throughput, delay, and jitter.

  4. Estimating TCP Packet Loss Ratio from Sampled ACK Packets

    Science.gov (United States)

    Yamasaki, Yasuhiro; Shimonishi, Hideyuki; Murase, Tutomu

    The advent of various quality-sensitive applications has greatly changed the requirements for IP network management and made the monitoring of individual traffic flows more important. Since the processing costs of per-flow quality monitoring are high, especially in high-speed backbone links, packet sampling techniques have been attracting considerable attention. Existing sampling techniques, such as those used in Sampled NetFlow and sFlow, however, focus on the monitoring of traffic volume, and there has been little discussion of the monitoring of such quality indexes as packet loss ratio. In this paper we propose a method for estimating, from sampled packets, packet loss ratios in individual TCP sessions. It detects packet loss events by monitoring duplicate ACK events raised by each TCP receiver. Because sampling reveals only a portion of the actual packet loss, the actual packet loss ratio is estimated statistically. Simulation results show that the proposed method can estimate the TCP packet loss ratio accurately from a 10% sampling of packets.

  5. Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development

    OpenAIRE

    Jose Antonio Aguilar Martinez; Neelima Roy Sinha

    2013-01-01

    TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found...

  6. Performance of TCP variants over LTE network

    Science.gov (United States)

    Nor, Shahrudin Awang; Maulana, Ade Novia

    2016-08-01

    One of the implementation of a wireless network is based on mobile broadband technology Long Term Evolution (LTE). LTE offers a variety of advantages, especially in terms of access speed, capacity, architectural simplicity and ease of implementation, as well as the breadth of choice of the type of user equipment (UE) that can establish the access. The majority of the Internet connections in the world happen using the TCP (Transmission Control Protocol) due to the TCP's reliability in transmitting packets in the network. TCP reliability lies in the ability to control the congestion. TCP was originally designed for wired media, but LTE connected through a wireless medium that is not stable in comparison to wired media. A wide variety of TCP has been made to produce a better performance than its predecessor. In this study, we simulate the performance provided by the TCP NewReno and TCP Vegas based on simulation using network simulator version 2 (ns2). The TCP performance is analyzed in terms of throughput, packet loss and end-to-end delay. In comparing the performance of TCP NewReno and TCP Vegas, the simulation result shows that the throughput of TCP NewReno is slightly higher than TCP Vegas, while TCP Vegas gives significantly better end-to-end delay and packet loss. The analysis of throughput, packet loss and end-to-end delay are made to evaluate the simulation.

  7. 基于TCP Reno和TCP Vegas拥塞控制性能研究%Research of congestion control performance based on TCP Reno and TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    刘国柱; 高文娟

    2011-01-01

    介绍了传输控制协议(TCP)的拥塞控制技术,对两种典型的TCP拥塞控制算法TCP Reno和TCP Vegas进行了详尽的分析,对其性能进行了比较.同时对TCP Reno和TCP Vegas在混存网络环境下的性能进行分析,并针对TCP Vegas中的α和β参数进行修改,提出了Vegas.A+算法使它们能并存于网络中.在NS2仿真环境下对改进的控制算法进行了仿真,仿真结果表明了改进算法的有效性.%The TCP (Transmission Control Protocol) congestion control techniques, and a detailed analysis of TCP Reno and TCP Vegas which are two typical TCP congestion control algorithms are mainly focused on. The performance of the TCP Reno and TCP Vegas in the mixed network environment is also analyzed, and not only the parameters α and β of the TCP Vegas are modified properly, but also an algorithm called Vegas-A+ is proposed, so that they can co-exist in the network. It is simulated by NS2, and proved the validity of the improved method.

  8. Internetworking with TCP/IP

    CERN Document Server

    Comer, Douglas E

    2014-01-01

    An internationally best-selling, conceptual introduction to the TCP/IP protocols and Internetworking, this book interweaves a clear discussion of fundamentals and scientific principles with details and examples drawn from the latest technologies. Leading author Douglas Comer covers layering and packet formats for all the Internet protocols, includingTCP, IPv4, IPv6, DHCP, and DNS. In addition, the text explains new trends in Internet systems, including packet classification, Software Defined Networking (SDN), and mesh protocols used in The Internet of Things. The text is appropriate for individuals interested in learning more about TCP/IP protocols, Internet architecture, and current networking technologies, as well as engineers who build network systems. It is suitable for junior to graduate-level courses in Computer Networks, Data Networks, Network Protocols, and Internetworking.

  9. Optical Switching Impact on TCP Throughput Limited by TCP Buffers

    NARCIS (Netherlands)

    Moura, Giovane C.M.; Fioreze, Tiago; Boer, de Pieter-Tjerk; Pras, Aiko; Nunzi, G.; Scoglio, C.; Li, X.

    2009-01-01

    In this paper, we observe the performance of TCP throughput when self-management is employed to automatically move flows from the IP level to established connections at the optical level. This move can result in many packets arriving out of order at the receiver and even being discarded, since some

  10. Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development.

    Science.gov (United States)

    Aguilar-Martínez, José A; Sinha, Neelima

    2013-01-01

    TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found for this group suggests similarity in gene function. Gene redundancy is characteristic in this group, as also seen in the class II TCP genes. We generated a pentuple mutant tcp8 tcp15 tcp21 tcp22 tcp23 and show that loss of function of these genes results in changes in leaf developmental traits. We also determined that these factors are able to mutually interact in a yeast two-hybrid assay and regulate the expression of KNOX1 genes. To circumvent the issue of genetic redundancy, dominant negative forms with SRDX repressor domain were used. Analysis of transgenic plants expressing AtTCP7-SRDX and AtTCP23-SRDX indicate a role of these factors in the control of cell proliferation.

  11. Networks and their traffic in multiplayer games

    Directory of Open Access Journals (Sweden)

    Cristian Andrés Melo López

    2016-06-01

    Full Text Available Computer games called multiplayer real-time, or (MCG are at the forefront of the use of the possibilities of the network. Research on this subject have been made for military simulations, virtual reality systems, computer support teamwork, the solutions diverge on the problems posed by MCG. With this in mind, this document provides an overview of the four issues affecting networking at the MCG. First, network resources (bandwidth, latency and computing capacity, together with the technical limits within which the MCG must operate. Second, the distribution concepts include communication architectures (peer-to-peer, client / server, server / network, and data and control architectures (centralized, distributed and reproduced .Thirdly, scalability allows the MCG to adapt to changes in parameterization resources. Finally, security is intended to fend off the traps and vandalism, which are common in online games; to check traffic, particularly these games we decided to take the massively multiplayer game League of Legends, a scene corresponding to a situation of real life in a network of ADSL access network is deployed has been simulated by using NS2 Three variants of TCP, it means SACK TCP, New Reno TCP, and TCP Vegas, have been considered for the cross traffic. The results show that TCP Vegas is able to maintain a constant speed while racing against the game traffic, since it avoids the packet loss and the delays in the tail caused by high peaks, without increasing the size of the sender window. SACK TCP and TCP New Reno, on the other hand, tend to increase continuously the sender window size, which could allow a greater loss of packages and also to cause unwanted delays for the game traffic.

  12. Experimental and Theoretical Analysis of Storage Friendly TCP Performance in Distributed Storage Area Network

    Directory of Open Access Journals (Sweden)

    Suresh Muknahallipatna

    2007-08-01

    Full Text Available Fibre channel storage area networks (SAN are widely implemented in production data center environments. Recently the storage industry has moved towards deployment of distributed SANs (DSAN, geographically dispersed across large physical distances. In a DSAN, specialized gateway devices interconnect the individual Fibre Channel (FC fabrics over IP networks using TCP/IP based protocols (iFCP or FCIP or over metro to long distance optical networks such as Dense Wavelength Division Multiplexing (DWDM based networks that utilize native FC ports supporting large numbers of link credits. When using TCP/IP based storage networking protocols to interconnect local FC fabrics in a DSAN, the sustained throughput achievable depends upon the link characteristics and TCP/IP stack implementation. Sustaining maximum possible storage traffic throughput across the wide area network enables practical DSAN deployments by maintaining the required site to site service level agreements.This study explores the effects of several TCP/IP modifications on sustained traffic throughput for a DSAN interconnected via iFCP gateways across an impaired network. The TCP/IP stack modifications, known as storage friendly, include changes to the window scaling, congestion avoidance, and fast recovery algorithms. The theoretical background and experimental results are presented to explain and illustrate these modifications.

  13. TCP Performance Enhancement for UMTS Access Network

    DEFF Research Database (Denmark)

    Hu, Liang

    2008-01-01

    We aim at optimize the TCP performance over UMTS access network challenged by the large delay bandwidth product that is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer. We propose to place a split TCP proxy at GGSN nodes which...... is between UMTS access network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products. Simulation results show, the split TCP proxy can significantly improve the TCP performance under high bit rate DCH channel...... scenario (e.g.256 kbps). Besides, the split TCP proxy brings more performance gain for downloading large files than downloading small ones. Finally, an aggressive initial TCP congestion window size at proxy can brings even more performance gain for radio links with high data rates DCH channels with large...

  14. AN ENHANCEMENT SCHEME OF TCP PROTOCOL IN MOBILE AD HOC NETWORKS: MME-TCP

    Institute of Scientific and Technical Information of China (English)

    Kai Caihong; Yu Nenghai; Chen Yuzhong

    2007-01-01

    Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper,a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP)designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore, these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs.

  15. MULTIMEDIA DATA TRANSMISSION THROUGH TCP/IP USING HASH BASED FEC WITH AUTO-XOR SCHEME

    Directory of Open Access Journals (Sweden)

    R. Shalin

    2012-09-01

    Full Text Available The most preferred mode for communication of multimedia data is through the TCP/IP protocol. But on the other hand the TCP/IP protocol produces huge packet loss unavoidable due to network traffic and congestion. In order to provide a efficient communication it is necessary to recover the loss of packets. The proposed scheme implements Hash based FEC with auto XOR scheme for this purpose. The scheme is implemented through Forward error correction, MD5 and XOR for providing efficient transmission of multimedia data. The proposed scheme provides transmission high accuracy, throughput and low latency and loss.

  16. OSI and TCP/IP

    Science.gov (United States)

    Randolph, Lynwood P.

    1994-01-01

    The Open Systems Interconnection Transmission Control Protocol/Internet Protocol (OSI TCP/IP) and the Government Open Systems Interconnection Profile (GOSIP) are compared and described in terms of Federal internetworking. The organization and functions of the Federal Internetworking Requirements Panel (FIRP) are discussed and the panel's conclusions and recommendations with respect to the standards and implementation of the National Information Infrastructure (NII) are presented.

  17. Potential performance bottleneck in Linux TCP

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenji; Crawford, Matt; /Fermilab

    2006-12-01

    TCP is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid-task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system to its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modeling and practical experiments; finally we propose and test one possible solution to resolve this performance bottleneck in Linux TCP.

  18. A Simulation Study of Paced TCP

    Science.gov (United States)

    Kulik, Joanna; Coulter, Robert; Rockwell, Dennis; Partridge, Craig

    2000-01-01

    In this paper, we study the performance of paced TCP, a modified version of TCP designed especially for high delay- bandwidth networks. In typical networks, TCP optimizes its send-rate by transmitting increasingly large bursts, or windows, of packets, one burst per round-trip time, until it reaches a maximum window-size, which corresponds to the full capacity of the network. In a network with a high delay-bandwidth product, however, Transmission Control Protocol's (TCPs) maximum window-size may be larger than the queue size of the intermediate routers, and routers will begin to drop packets as soon as the windows become too large for the router queues. The TCP sender then concludes that the bottleneck capacity of the network has been reached, and it limits its send-rate accordingly. Partridge proposed paced TCP as a means of solving the problem of queueing bottlenecks. A sender using paced TCP would release packets in multiple, small bursts during a round-trip time in which ordinary TCP would release a single, large burst of packets. This approach allows the sender to increase its send-rate to the maximum window size without encountering queueing bottlenecks. This paper describes the performance of paced TCP in a simulated network and discusses implementation details that can affect the performance of paced TCP.

  19. TCP/IP-sokettiohjelmoinnin sovelluslogiikka

    OpenAIRE

    Savolainen, Stanislav

    2014-01-01

    Insinöörityö kertoo, miten TCP-sokettien sovelluslogiikka rakentuu ja miten sitä voi käyttää ohjelmistoprojektissa. Voidaan tehdä omia verkkosovelluksia esimerkiksi web-selaimia, http-palvelimia, monipelejä, chat-ohjelmia, tiedostojakeluohjelmia ja muita sovelluksia. Työ näyttää myös sen, että verkko-ohjelmoinnin opettelun aloitusvaihe ei ole kovin vaikeaa eikä tarvitse tietää paljon tietoliikenteestä aloittaakseen yksinkertaisten omien verkko-ohjelmien teon. Kerron askel kerrallaan, mite...

  20. TCP/IP Network Administration

    CERN Document Server

    Hunt, Craig

    2002-01-01

    This complete guide to setting up and running a TCP/IP network is essential for network administrators, and invaluable for users of home systems that access the Internet. The book starts with the fundamentals -- what protocols do and how they work, how addresses and routing are used to move data through the network, how to set up your network connection -- and then covers, in detail, everything you need to know to exchange information via the Internet. Included are discussions on advanced routing protocols (RIPv2, OSPF, and BGP) and the gated software package that implements them, a tutorial

  1. TCP Performance Enhancement Over Iridium

    Science.gov (United States)

    Torgerson, Leigh; Hutcherson, Joseph; McKelvey, James

    2007-01-01

    In support of iNET maturation, NASA-JPL has collaborated with NASA-Dryden to develop, test and demonstrate an over-the-horizon vehicle-to-ground networking capability, using Iridium as the vehicle-to-ground communications link for relaying critical vehicle telemetry. To ensure reliability concerns are met, the Space Communications Protocol Standards (SCPS) transport protocol was investigated for its performance characteristics in this environment. In particular, the SCPS-TP software performance was compared to that of the standard Transmission Control Protocol (TCP) over the Internet Protocol (IP). This paper will report on the results of this work.

  2. Enhancing Energy Efficient TCP by Partial Reliability

    NARCIS (Netherlands)

    Donckers, L.; Smit, G.J.M.; Smit, L.T.

    2002-01-01

    We present a study on the effects on a mobile system's energy efficiency of enhancing, with partial reliability, our energy efficient TCP variant (E/sup 2/TCP) (see Donckers, L. et al., Proc. 2nd Asian Int. Mobile Computing Conf. - AMOC2002, p.18-28, 2002). Partial reliability is beneficial for mult

  3. TCP transcription factors: architectures of plant form.

    Science.gov (United States)

    Manassero, Nora G Uberti; Viola, Ivana L; Welchen, Elina; Gonzalez, Daniel H

    2013-04-01

    After its initial definition in 1999, the TCP family of transcription factors has become the focus of a multiplicity of studies related with plant development at the cellular, organ, and tissue levels. Evidence has accumulated indicating that TCP transcription factors are the main regulators of plant form and architecture and constitute a tool through which evolution shapes plant diversity. The TCP transcription factors act in a multiplicity of pathways related with cell proliferation and hormone responses. In recent years, the molecular pathways of TCP protein action and biochemical studies on their mode of interaction with DNA have begun to shed light on their mechanism of action. However, the available information is fragmented and a unifying view of TCP protein action is lacking, as well as detailed structural studies of the TCP-DNA complex. Also important, the possible role of TCP proteins as integrators of plant developmental responses to the environment has deserved little attention. In this review, we summarize the current knowledge about the structure and functions of TCP transcription factors and analyze future perspectives for the study of the role of these proteins and their use to modify plant development.

  4. Mechanism of lubrication by tricresylphosphate (TCP)

    Science.gov (United States)

    Faut, O. D.; Buckley, D. H.

    1984-01-01

    The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

  5. Analysis of Proactive and Reactive Manet Routing Protocols Under Selected TCP Variants

    Directory of Open Access Journals (Sweden)

    Iffat Syad

    2013-08-01

    Full Text Available A Mobile Ad hoc Network (MANET, with its inherent dynamic and flexible architecture, demonstrates attractive potential for military applications. It is able to overcome traditional communications limitations through its automatic relaying and self - healing/forming features. MANE T nodes perform the routing functions themselves. Due to the limited wireless transmission range, the routing generally consists of multiple hops. Therefore, the nodes depend on one another to forward packets to the destinations. In a Mobile Ad Hoc Network (MANET, temporary link failures and route changes happen frequently. With the assumption that all packet losses are due to congestion, Transport Control Protocol (TCP performs poorly in such an environment. One problem of TCP in such environments is its inability to distinguish losses induced by the lossy wireless channel from the ones due to network congestion. Many TCP variants have been developed for the improved performance of TCP in MANET. In this research, through simulations that were carried out by using Network Simulator-2 (NS-2 , the selected MANET Routing protocols i.e. DSR and DSDV were analyzed in accordance with their finest performance of packets delivery rate, average end - to - end delay, and packet dropping, under TCP Vegas and TCP Newreno with mobility consideration. The simulation results indicate that DSDV has a b etter throughput performance but higher average end-to-end delay and packet drop ratioas compared to DSR

  6. Improving Quality of Service from TCP/IP Performance Degradation

    Directory of Open Access Journals (Sweden)

    Prof.N..Penchalaiah

    2011-02-01

    Full Text Available TCP is currently the dominate congestion control protocol for the Internet. However, as the Internet evolves into a high-speed wired-cum-wireless hybrid network, performance degradation problems of TCP have appeared, such as underutilizing high-speed links, regarding wireless loss as congestion signal, and unfairness among flows with different RTTs. In order to improve the quality of service for such highspeed hybrid networks, we propose a router-assisted congestion control protocol called Quick Flow Control Protocol (QFCP. The convergence of many traditional services over IPbased infrastructures drastically increases the amount of IP data traffic to be delivered to user clients, thus raising questions about the management of quality of service in such networks. Quality of service will be of primary importance in order to ensure right operation, and to face the occurrence of congestion conditions, due to bandwidth demandingmultimedia services. in this paper, shows that QFCP can significantly shorten flow completion time, fairly allocate bandwidth resource, and be robust to non-congestion related loss. Also we consider a possible scenarios in which multiple multimedia and control streams are conveyed over the same HAN, and study a possible solution for the implementation of an easily manageable QoS framework, that relies on a QoS router based on open source software.

  7. Analysis list: TCP1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available TCP1 Digestive tract,Epidermis,Prostate + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/TCP...1.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/TCP1.5.tsv http://dbarc...hive.biosciencedbc.jp/kyushu-u/hg19/target/TCP1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP...1.Digestive_tract.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP...1.Epidermis.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP1.Prostate.tsv http://dbarchive.bios

  8. 浅析TCP/IP协议及其安全%Analysis on TCP/IP Protocol and Its Security

    Institute of Scientific and Technical Information of China (English)

    李东灵; 毛自民

    2012-01-01

    本文主要讨论TCP/IP协议内容,以及TCP/IP协议的安全问题和几种常见的网络攻击手段.%This paper mainly discusses the TCP/IP protocol, and TCP/IP protocol security problems and some common network attack means.

  9. TCP/IP Network In Process Control Plants%过程控制中的TCP/IP网络

    Institute of Scientific and Technical Information of China (English)

    牟连佳; 王立明

    2002-01-01

    提出TCP/IP在过程控制中的应用. 评价TCP/IP控制系统性能,通过传统控制系统与TCP/IP控制系统的比较,指出采用TCP/IP 控制系统的优缺点. 说明过程控制技术中,采用TCP/IP是一种更好的选择.

  10. TCP NCE: A unified solution for non-congestion events to improve the performance of TCP over wireless networks

    Directory of Open Access Journals (Sweden)

    Sreekumari Prasanthi

    2011-01-01

    Full Text Available Abstract In this article, we propose a unified solution called Transmission Control Protocol (TCP for Non-Congestion Events (TCP NCE, to overcome the performance degradation of TCP due to non-congestion events over wireless networks. TCP NCE is capable to reduce the unnecessary reduction of congestion window size and retransmissions caused by non-congestion events such as random loss and packet reordering. TCP NCE consists of three schemes. Detection of non-congestion events (NCE-Detection, Differentiation of non-congestion events (NCE-Differentiation and Reaction to non-congestion events (NCE-Reaction. For NCE-Detection, we compute the queue length of the bottleneck link using TCP timestamp and for NCE-Differentiation, we utilize the flightsize information of the network with a dynamic delay threshold value. We introduce a new retransmission algorithm called 'Retransmission Delay' for NCE-Reaction which guides the TCP sender to react to non-congestion events by properly triggering the congestion control mechanism. According to the extensive simulation results using qualnet network simulator, TCP NCE acheives more than 70% throughput gain over TCP CERL and more than 95% throughput improvement as compared to TCP NewReno, TCP PR, RR TCP, TCP Veno, and TCP DOOR when the network coexisted with congestion and non-congestion events. Also, we compared the accuracy and fairness of TCP NCE and the result shows significant improvement over existing algorithms in wireless networks.

  11. Carrying Capacity

    DEFF Research Database (Denmark)

    Schroll, Henning; Andersen, Jan; Kjærgård, Bente

    2012-01-01

    A spatial planning act was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive...... carrying capacity (SCC) and assimilative carrying capacity (ACC). The act mandates that the latter two aspects must be taken into consideration in the local spatial plans. The present study aimed at developing a background for a national guideline for carrying capacity in Indonesian provinces and districts...... standard or governmental political objective exists. In most cases it was possible to select a set of indicators, including thresholds that are workable in a carrying capacity planning at the local administrative levels. Not all relevant sectors at the decentralized level were included. Indicators of SCC...

  12. 10 Gbps TCP/IP streams from the FPGA for the CMS DAQ Eventbuilder Network

    CERN Document Server

    Bauer, Gerry; Branson, James; Chaze, Olivier; Cittolin, Sergio; Coarasa Perez, Jose Antonio; Darlea, Georgiana Lavinia; Deldicque, Christian; Dobson, Marc; Dupont, Aymeric; Erhan, Samim; Gigi, Dominique; Glege, Frank; Gomez Ceballos, Guillelmo; Gomez-Reino Garrido, Robert; Hartl, Christian; Hegeman, Jeroen Guido; Holzner, Andre Georg; Masetti, Lorenzo; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; Nunez Barranco Fernandez, Carlos; O'Dell, Vivian; Orsini, Luciano; Ozga, Wojciech Andrzej; Paus, Christoph Maria Ernst; Petrucci, Andrea; Pieri, Marco; Racz, Attila; Raginel, Olivier; Sakulin, Hannes; Sani, Matteo; Schwick, Christoph; Spataru, Andrei Cristian; Stieger, Benjamin Bastian; Sumorok, Konstanty; Veverka, Jan; Wakefield, Christopher Colin; Zejdl, Petr

    2013-01-01

    For the upgrade of the DAQ of the CMS experiment in 2013/2014 an interface between the custom detector Front End Drivers (FEDs) and the new DAQ eventbuilder network has to be designed. For a loss-less data collection from more then 600 FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. We present the hardware challenges and protocol modifications made to TCP in order to simplify its FPGA implementation together with a set of performance measurements which were carried out with the current prototype.

  13. On the impact of TCP and per-flow scheduling on Internet performance (extended version)

    CERN Document Server

    Carofiglio, Giovanna

    2009-01-01

    Internet performance is tightly related to the properties of TCP and UDP protocols, jointly responsible for the delivery of the great majority of Internet traffic. It is well understood how these protocols behave under FIFO queuing and what the network congestion effects. However, no comprehensive analysis is available when flow-aware mechanisms such as per-flow scheduling and dropping policies are deployed. Previous simulation and experimental results leave a number of unanswered questions. In the paper, we tackle this issue by modeling via a set of fluid non-linear ODEs the instantaneous throughput and the buffer occupancy of N long-lived TCP sources under three per-flow scheduling disciplines (Fair Queuing, Longest Queue First, Shortest Queue First) and with longest queue drop buffer management. We study the system evolution and analytically characterize the stationary regime: closed-form expressions are derived for the stationary throughput/sending rate and buffer occupancy which give thorough understandi...

  14. Priority probability deceleration deadline-aware TCP

    Institute of Scientific and Technical Information of China (English)

    Jin Ye; Jing Lin; Jiawei Huang

    2015-01-01

    In modern data centers, because of the deadline-agnostic congestion control in transmission control protocol (TCP), many deadline-sensitive flows can not finish before their deadlines. Therefore, providing a higher deadline meeting ratio becomes a critical chal enge in the typical online data intensive (OLDI) ap-plications of data center networks (DCNs). However, a problem named as priority synchronization is found in this paper, which de-creases the deadline meeting ratio badly. To solve this problem, we propose a priority probability deceleration (P2D) deadline-aware TCP. By using the novel probabilistic deceleration, P2D prevents the priority synchronization problem. Simulation results show that P2 D increases the deadline meeting ratio by 20%compared with D2TCP.

  15. Traffic engineering for Internet applications

    Science.gov (United States)

    Jena, Ajit K.; Popescu, Adrian

    2001-07-01

    The focus of the paper is on resource engineering for supporting Service Level Agreements (SLAs) in IP networks. SLA at both link level and application level are considered. Using an object-oriented simulation model a case study is presented for client-server interactions generated by mixed traffic conditions in a Frame Relay (FR) WAN. Performance issues of Short Range Dependence and Long Range Dependence traffic under different resource control regimes are compared. The results show that major portion of the end-to- end delay comes from the queueing delay at the WAN ingress points, which is due to the significant bandwidth differences that may exist between LAN and WAN link layers. The results also highlight the role TCP window size and FR PVC control mechanisms play in the provision of delay performance for Internet services.

  16. SET: Session Layer-Assisted Efficient TCP Management Architecture for 6LoWPAN with Multiple Gateways

    Directory of Open Access Journals (Sweden)

    Akbar AliHammad

    2010-01-01

    Full Text Available 6LoWPAN (IPv6 based Low-Power Personal Area Network is a protocol specification that facilitates communication of IPv6 packets on top of IEEE 802.15.4 so that Internet and wireless sensor networks can be inter-connected. This interconnection is especially required in commercial and enterprise applications of sensor networks where reliable and timely data transfers such as multiple code updates are needed from Internet nodes to sensor nodes. For this type of inbound traffic which is mostly bulk, TCP as transport layer protocol is essential, resulting in end-to-end TCP session through a default gateway. In this scenario, a single gateway tends to become the bottleneck because of non-uniform connectivity to all the sensor nodes besides being vulnerable to buffer overflow. We propose SET; a management architecture for multiple split-TCP sessions across a number of serving gateways. SET implements striping and multiple TCP session management through a shim at session layer. Through analytical modeling and ns2 simulations, we show that our proposed architecture optimizes communication for ingress bulk data transfer while providing associated load balancing services. We conclude that multiple split-TCP sessions managed in parallel across a number of gateways result in reduced latency for bulk data transfer and provide robustness against gateway failures.

  17. A Robust Statistical Estimation of Internet Traffic

    CERN Document Server

    Chabchoub, Yousra; Guillemin, Fabrice; Robert, Philippe

    2009-01-01

    A new method of estimating flow characteristics in the Internet is developped in this paper. For this purpose, a new set of random variables (referred to as observables) is defined. When dealing with sampled traffic, these observables can easily be computed from sampled data. By adopting a convenient mouse/elephant dichotomy also {\\em dependent on traffic}, it is shown how these variables give a {\\em robust} statistical information of long flows. A mathematical framework is developed to estimate the accuracy of the method. As an application, it is shown how one can estimate the number of long TCP flows when only sampled traffic is available. The algorithm proposed is tested against experimental data collected from different types of IP traffic.

  18. Network Characteristics of Video Streaming Traffic

    CERN Document Server

    Rao, Ashwin; Barakat, Chadi; Legout, Arnaud; Towsley, Don; Dabbous, Walid

    2011-01-01

    Video streaming represents a large fraction of Internet traffic. Surprisingly, little is known about the network characteristics of this traffic. In this paper, we study the network characteristics of the two most popular video streaming services, Netflix and YouTube. We show that the streaming strategies vary with the type of the application (Web browser or native mobile application), and the type of container (Silverlight, Flash, or HTML5) used for video streaming. In particular, we identify three different streaming strategies that produce traffic patterns from non-ack clocked ON-OFF cycles to bulk TCP transfer. We then present an analytical model to study the potential impact of these streaming strategies on the aggregate traffic and make recommendations accordingly.

  19. Predicting TCP congestion through active and passive measurments

    OpenAIRE

    Hassan, Ismail Ali

    2005-01-01

    The Transmission Control Protocol (TCP) has proved to be a reliable transport protocol that has withstood the test of time. It is part of the TCP/IP protocol suite deployed on the Internet, and it currently supports a variety of underlying networking technologies such as Wireless, Satellite and High-Speed networks. The congestion control mechanism used by current implementation of TCP (known as TCP-Reno/new Reno) is based on the Additive Increase Multiple Decrease (AIMD) algorithm that wa...

  20. A survey of TCP over ad hoc networks

    NARCIS (Netherlands)

    Al Hanbali, Ahmad; Altman, Eitan; Nain, Philippe

    2005-01-01

    The Transmission Control Protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless ad hoc networks can lead to TCP implemen

  1. NetBEUI, IPX/SPX and TCP/IP%NetBEUI、IPX/SPX、TCP/IP之比较

    Institute of Scientific and Technical Information of China (English)

    王敏琴

    2001-01-01

    目前较流行的通信协议有NetBEUI、IPX/SPX、TCP/IP等.NetBEUI适合小型局域网,IPX/SPX则为Novell网的通信协议,TCP/IP为Internet协议.IPX/SPX、TCP/IP为可路由协议.NetBEUI、IPX/SPX不需设置,TCP/IP需设置其"IP地址"、"子网掩码"、"默认网关"、"主机名"等.

  2. Fast parallelized TCP/IP stack for high-speed network intrusion detection systems%用于高速网络入侵检测系统的并行TCP/IP协议栈

    Institute of Scientific and Technical Information of China (English)

    夏高; 刘斌

    2011-01-01

    Since the speed of application layer content detection has been increased to 10 Gb/s,TCP/IP stacks have become the new bottle-neck in network intrusion detection systems.Previous systems have used 64 bit instructions,parallel instructions and kernel space memory mapping to speed up the bottle-necks,such as the TCP checksum computation,TCP connection table Hash value calculation and data copies from the kernel space to the user space.A method was developed using universal Hash in the TCP connection lookup table to avoid algorithmic complexity attacks and to speed up the computations using the parallel instructions in the SSE(streaming SIMD extensions) instruction set.A Bloom filter is used to filter TCP half-open connections.The TCP/IP stack was then parallelized using multi-loaded dynamic-link library(DLL) to achieve higher throughput.Evaluations show that a TCP/IP stack using these three processing cores is able to deliver 4.4 Gb/s throughput against attacking traffic with an average packet size of 110 Bytes and 15.2 Gb/s with normal traffic with an average packet size of 501 Bytes,which is 4 times the speed of the original system and 50%-70% higher than the authors' previous work.%随着网络应用层内容检测技术的速度提高到10Gb/s的数量级,底层的TCP/IP协议栈已经成为制约网络入侵检测系统的检测速度的新瓶颈。该文的前期工作采用64位指令、并行计算指令和操作系统内核数据映射等软件硬件系统特性来优化TCP校验码计算、TCP连接表Hash值计算和内核态到用户态的数据复制等性能瓶颈。在此基础上,该文进一步研究了连接表Hash值计算、半开连接过滤和并行化问题,采用通用Hash(universal Hash)函数作为TCP连接表查找的Hash函数,以避免算法复杂度攻击,并利用SSE(stre

  3. Running TCP/IP over ATM Networks.

    Science.gov (United States)

    Witt, Michael

    1995-01-01

    Discusses Internet protocol (IP) and subnets and describes how IP may operate over asynchronous transfer mode (ATM). Topics include TCP (transmission control protocol), ATM cells and adaptation layers, a basic architectural model for IP over ATM, address resolution, mapping IP to a subnet technology, and connection management strategy. (LRW)

  4. System level traffic shaping in disk servers with heterogeneous protocols

    Science.gov (United States)

    Cano, Eric; Kruse, Daniele Francesco

    2014-06-01

    Disk access and tape migrations compete for network bandwidth in CASTORs disk servers, over various protocols: RFIO, Xroot, root and GridFTP. As there are a limited number of tape drives, it is important to keep them busy all the time, at their nominal speed. With potentially 100s of user read streams per server, the bandwidth for the tape migrations has to be guaranteed to a controlled level, and not the fair share the system gives by default. Xroot provides a prioritization mechanism, but using it implies moving exclusively to the Xroot protocol, which is not possible in short to mid-term time frame, as users are equally using all protocols. The greatest commonality of all those protocols is not more than the usage of TCP/IP. We investigated the Linux kernel traffic shaper to control TCP/ IP bandwidth. The performance and limitations of the traffic shaper have been understood in test environment, and satisfactory working point has been found for production. Notably, TCP offload engines' negative impact on traffic shaping, and the limitations of the length of the traffic shaping rules were discovered and measured. A suitable working point has been found and the traffic shaping is now successfully deployed in the CASTOR production systems at CERN. This system level approach could be transposed easily to other environments.

  5. Performance Evaluation of TCP over Mobile Ad hoc Networks

    CERN Document Server

    Ahmed, Foez; Islam, Nayeema; Debnath, Sumon Kumar

    2010-01-01

    With the proliferation of mobile computing devices, the demand for continuous network connectivity regardless of physical location has spurred interest in the use of mobile ad hoc networks. Since Transmission Control Protocol (TCP) is the standard network protocol for communication in the internet, any wireless network with Internet service need to be compatible with TCP. TCP is tuned to perform well in traditional wired networks, where packet losses occur mostly because of congestion. However, TCP connections in Ad-hoc mobile networks are plagued by problems such as high bit error rates, frequent route changes, multipath routing and temporary network partitions. The throughput of TCP over such connection is not satisfactory, because TCP misinterprets the packet loss or delay as congestion and invokes congestion control and avoidance algorithm. In this research, the performance of TCP in Adhoc mobile network with high Bit Error rate (BER) and mobility is studied and investigated. Simulation model is implement...

  6. Research on Application of Perceived QoS Guarantee through Infrastructure Specific Traffic Parameter Optimization

    Directory of Open Access Journals (Sweden)

    Vikram Jeet Singh

    2014-02-01

    Full Text Available The technological developments in the fields of multimedia clinical applications and communication networks require a specific analysis to increase the efficiency of network based healthcare services. In this work, we computed the optimum transmission parameter (data packet size for applications needed to guarantee the perceived quality of service in the proposed ubiquitous healthcare network. This has been carried out through NS2 based simulation of a state wide area network infrastructure implemented in Himachal Pradesh, a state with diverse geographical terrain situated in the Western Himalayan region of India. The various types of healthcare applications and services have been classified into different classes according to their perceived QOS requirements as per the guidelines in ITU report on network performance objectives. The infrastructure specific optimum values of data packet size for these QoS classes have been computed. Network based healthcare applications and services running on both TCP and UDP type of traffic have been presented in this paper.

  7. On the Impact of Zero-padding in Network Coding Efficiency with Internet Traffic and Video Traces

    DEFF Research Database (Denmark)

    Taghouti, Maroua; Roetter, Daniel Enrique Lucani; Pedersen, Morten Videbæk

    2016-01-01

    the efficiency of RLNC or other erasure coding techniques. Our goal is to characterize the overhead generated by this zero-padding under real-traffic traces. These include TCP and UDP traces from traffic at core routers from CAIDA and a collection of video traces for different codecs and video resolution...

  8. Identification of a TcpC-TcpQ Outer Membrane Complex Involved in the Biogenesis of the Toxin-Coregulated Pilus of Vibrio cholerae

    OpenAIRE

    Bose, Niranjan; Taylor, Ronald K.

    2005-01-01

    The toxin-coregulated pilus (TCP) of Vibrio cholerae and the soluble TcpF protein that is secreted via the TCP biogenesis apparatus are essential for intestinal colonization. The TCP biogenesis apparatus is composed of at least nine proteins but is largely uncharacterized. TcpC is an outer membrane lipoprotein required for TCP biogenesis that is a member of the secretin protein superfamily. In the present study, analysis of TcpC in a series of strains deficient in each of the TCP biogenesis p...

  9. IMPLEMENTASI PROTOKOL TCP/IP UNTUK PENGENDALIAN KOMPUTER JARAK JAUH

    Directory of Open Access Journals (Sweden)

    Rudy Adipranata

    2002-01-01

    Full Text Available This day, computer networking has become important necessity for data exchange between computers. And along with the growing of number of computer in a network, the difficulty for managing that network also increased. Because of that reality, in this paper will be build application for remote controlling computer using TCP/IP protocol. This application build using Delphi 5.0 programming language and dWinsock 2.75, component interface for Windows Socket API which is created especially for Delphi language, and separate to two sub applications, namely server application, which run on computer to be controlled and the secondly is client application, run on controller computer. In this application, data text or binary will be send, so two pair components will be used : TTextServer - TTextClient and TBinaryServer- TBinaryClient. The functions which implemented in this applications are : lock and unlock computer, reboot, shutdown, execute remote program, send message, capture screen and view remote programs. Test is doing on internal network and internet network, and the result of that test for internal network, all of functions can be activated perfectly without significant delay (less than 1 second. But for internet network, there is delay, which the number variable depend on data traffic at that moment. Abstract in Bahasa Indonesia : Sekarang ini jaringan komputer sudah menjadi suatu kebutuhan yang sangat penting untuk mempermudah pertukaran data antar komputer. Dan seiring dengan makin berkembangnya jumlah komputer pada suatu jaringan, maka makin bertambah pula tingkat kesulitan untuk mengelola jaringan tersebut. Oleh sebab itu pada penelitian ini akan dibuat aplikasi untuk mengendalikan komputer secara jarak jauh dengan menggunakan protokol TCP/IP. Aplikasi ini dibuat dengan menggunakan bahasa pemrograman Delphi 5.0 dan dWinsock 2.75 yang merupakan komponen antar muka Windows Socket API yang dikhususkan untuk bahasa pemrograman Delphi, dan terdiri

  10. Traffic Measurement for Traffic Engineering in IP/MPLS Based Telecom Core Networks

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Telecommunication networks will become IP-based networks with all voice, data and multimedia traffic carried as packets with appropriate quality and class of service for each traffic type. It is very important for service provider to apply Traffic Engineering (TE) with the dramatic growth of networks traffic. In this paper, we discuss traffic engineering based on IP/MPLS and emphasize traffic measurement in telecom core networks. We specify the technology and scientific principles of the measurement, modeling, characterization, and the traffic flow matrix. The paper concludes with a preliminary analysis of TE measurement and a discussion about the development of TE measurement.

  11. Phase diagram distortion from traffic parameter averaging.

    NARCIS (Netherlands)

    Stipdonk, H. Toorenburg, J. van & Postema, M.

    2010-01-01

    Motorway traffic congestion is a major bottleneck for economic growth. Therefore, research of traffic behaviour is carried out in many countries. Although well describing the undersaturated free flow phase as an almost straight line in a (k,q)-phase diagram, congested traffic observations and theori

  12. Media-TCP: A Quality-Centric TCP-Friendly Congestion Control for Multimedia Transmission

    CERN Document Server

    Shiang, Hsien-Po

    2009-01-01

    In this paper, we propose a quality-centric congestion control for multimedia streaming over IP networks, which we refer to as media-TCP. Unlike existing congestion control schemes that adapt a user's sending rate merely to the network condition, our solution adapts the sending rate to both the network condition and the application characteristics by explicitly considering the distortion impacts, delay deadlines, and interdependencies of different video packet classes. Hence, our media-aware solution is able to provide differential services for transmitting various packet classes and thereby, further improves the multimedia streaming quality. We model this problem using a Finite-Horizon Markov Decision Process (FHMDP) and determine the optimal congestion control policy that maximizes the long-term multimedia quality, while adhering to the horizon- TCP-friendliness constraint, which ensures long-term fairness with existing TCP applications. We show that the FHMDP problem can be decomposed into multiple optimal...

  13. TCP-ATCA: Improved Transmission Control Algorithm in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    Liu Feng; Liu Hengna; Zhao Han

    2008-01-01

    An adaptive transmission control algorithm based on TCP (TCP-ATCA) is proposed to reduce the effects of long propagation de- lay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification (DRED-ECN) algorithm, and, moreover, the pertaining con- gestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unneces- sary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher (≥ 600 packet/s), and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.

  14. An analysis of network traffic classification for botnet detection

    DEFF Research Database (Denmark)

    Stevanovic, Matija; Pedersen, Jens Myrup

    2015-01-01

    Botnets represent one of the most serious threats to the Internet security today. This paper explores how can network traffic classification be used for accurate and efficient identification of botnet network activity at local and enterprise networks. The paper examines the effectiveness...... of detecting botnet network traffic using three methods that target protocols widely considered as the main carriers of botnet Command and Control (C&C) and attack traffic, i.e. TCP, UDP and DNS. We propose three traffic classification methods based on capable Random Forests classifier. The proposed methods...... to the optimization of traffic analysis and the correlation of findings from the three analysis methods in order to identify compromised hosts within the network....

  15. Detecting bots using multi-level traffic analysis

    DEFF Research Database (Denmark)

    Stevanovic, Matija; Pedersen, Jens Myrup

    2016-01-01

    Botnets, as networks of compromised “zombie” computers, represent one of the most serious security threats on the Internet today. This paper explores how machines compromised with bot malware can be identified at local and enterprise networks in accurate and time-efficient manner. The paper...... introduces a novel multi-level botnet detection approach that performs network traffic analysis of three protocols widely considered as the main carriers of botnet Command and Control (C&C) and attack traffic, i.e. TCP, UDP and DNS. The proposed method relies on supervised machine learning for identifying...... patterns of botnet network traffic. The method has been evaluated through a series of experiments using traffic traces originating from 40 different bot samples and diverse benign applications. The evaluation indicates accurate and time-efficient classification of botnet traffic for all the three protocols...

  16. Performance of OpenDPI in Identifying Sampled Network Traffic

    Directory of Open Access Journals (Sweden)

    Jawad M Khalife

    2013-01-01

    Full Text Available The identification of the nature of the traffic flowing through a TCP/IP network is a relevant target for traffic engineering and security related tasks. Despite the privacy concerns it arises, Deep Packet Inspection (DPI is one of the most successful current techniques. Nevertheless, the performance of DPI is strongly limited by computational issues related to the huge amount of data it needs to handle, both in terms of number of packets and the length of the packets. One way to reduce the computational overhead with identification techniques is to sample the traffic being monitored. This paper addresses the sensitivity of OpenDPI, one of the most powerful freely available DPI systems, with sampled network traffic. Two sampling techniques are applied and compared: the per-packet payload sampling, and the per-flow packet sampling. Based on the obtained results, some conclusions are drawn to show how far DPI methods could be optimised through traffic sampling.

  17. Traffic Monitor

    Science.gov (United States)

    1992-01-01

    Mestech's X-15 "Eye in the Sky," a traffic monitoring system, incorporates NASA imaging and robotic vision technology. A camera or "sensor box" is mounted in a housing. The sensor detects vehicles approaching an intersection and sends the information to a computer, which controls the traffic light according to the traffic rate. Jet Propulsion Laboratory technical support packages aided in the company's development of the system. The X-15's "smart highway" can also be used to count vehicles on a highway and compute the number in each lane and their speeds, important information for freeway control engineers. Additional applications are in airport and railroad operations. The system is intended to replace loop-type traffic detectors.

  18. Wire-Compatible Unordered Delivery in TCP and TLS

    CERN Document Server

    Iyengar, Janardhan; Amin, Syed Obaid; Nowlan, Michael F; Tiwari, Nabin

    2011-01-01

    The performance of many common Internet applications can benefit from out-of-order delivery, a feature all IETF transports since TCP have included. Yet latency-sensitive applications still frequently build on in-order TCP despite its performance drawbacks, for reasons such as network compatibility and TCP's cultural inertia. We introduce uTCP, an API extension that adds out-of-order delivery support without changing TCP's wire protocol, by delivering received TCP segments to the application immediately on arrival along with sequence number metadata. To obtain robust out-of-order delivery across middleboxes that may re-segment TCP flows, the application employs a "record-marking" content encoding such as COBS, allowing the receiver to extract records from a byte stream with arbitrary holes. TLS can also serve as such an encoding, enabling applications to obtain out-of-order delivery in a stream indistinguishable in the network from conventional TLS over TCP. With uTCP, for example, voice/videoconferencing appl...

  19. Performance Analysis of TCP-Reno and TCP-Sack in the Case of a Single Source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work explores the behavior of both TCP-Reno and TCP-Sack under a simple scenario, where a single TCP source transmits the packets continuously over a single bottleneck node characterized by its queue size, bandwidth and propagation delay. The analysis allows to derive the performance of TCP, the utilization tends to 75% of the bottleneck throughput when the bandwidth × propagation delay pipe becomes very large, while it tends to 100% when the queuing delays are predominant because the queue is never empty. In the transient analysis we show how the initial phase of the session can degrade the performances. These results are proved through simulation.

  20. Characterization of P2P IPTV Traffic: Scaling Analysis

    CERN Document Server

    Silverston, Thomas; Salamatian, Kave

    2007-01-01

    P2P IPTV applications arise on the Internet and will be massively used in the future. It is expected that P2P IPTV will contribute to increase the overall Internet traffic. In this context, it is important to measure the impact of P2P IPTV on the networks and to characterize this traffic. During the 2006 FIFA World Cup, we performed an extensive measurement campaign. We measured network traffic generated by broadcasting soccer games by the most popular P2P IPTV applications, namely PPLive, PPStream, SOPCast and TVAnts. From the collected data, we characterized the P2P IPTV traffic structure at different time scales. To the best of our knowledge, this is the first work, which presents a complete multiscale analysis of the P2P IPTV traffic. Our observations show that the network traffic has not the same scale behavior whether the applications use TCP or UDP. For all the applications, the download traffic is different from the upload traffic and the signaling traffic has an impact on the download traffic.

  1. TCP/IP Protocol and Information Security%TCP/IP协议与信息安全

    Institute of Scientific and Technical Information of China (English)

    陈彦君

    2011-01-01

    TCP/IP agreement, although there are serious security problems, but still has its own Security. In this paper, the TCP/IP protocol working principle were briefly reviewed in this paper, and discussed the TCP/IP protocol in information security is the safety and the safety of the existing problems. And to how the TCP/IP protocol to protect information security was briefly discussed in this paper.%TCP/IP协议虽然存在着严重的安全隐患,但是仍然有着其自己独有的安全性。本文对TCP/IP、协议工作原理进行了简要的介绍,讨论了TCP/IP协议在信息安全方面所具有的安全性与存在的安全问题,并对如何利用TCP/IP协议来保护信息安全进行了简要的探讨。

  2. Integration of Linux TCP and Simulation: Verification, Validation and Application

    Directory of Open Access Journals (Sweden)

    Songrith Kittiperachol

    2009-11-01

    Full Text Available Network simulator has been acknowledged as one of the most flexible means in studying and developing protocol as it allows virtually endless numbers of simulated network environments to be setup and protocol of interest to be fine-tuned without requiring any real-world complicated and costly network experiment. However, depending on researchers, the same protocol of interest can be developed in different ways and different implementations may yield the outcomes that do not accurately capture the dynamics of the real protocol. In the last decade, TCP, the protocol on which the Internet is based, has been extensively studied in order to study and reevaluate its performance particularly when TCP based applications and services are deployed in an emerging Next Generation Network (NGN and Next Generation Internet (NGI. As a result, to understand the realistic interaction of TCP with new types of networks and technologies, a combination of a real-world TCP and a network simulator seems very essential. This work presents an integration of real-world TCP implementation of Linux TCP/IP network stack into a network simulator, called INET. Moreover, verification and validation of the integrated Linux TCP are performed within INET framework to ensure the validity of the integration. The results clearly confirm that the integrated Linux TCP displays reasonable and consistent dynamics with respect to the behaviors of the real-world Linux TCP. Finally, to demonstrate the application of the INET with Linux TCP extension, algorithms of other Linux TCP variants and their dynamic over a large-bandwidth long-delay network are briefly presented.

  3. ON THE RELEVANCE OF ON-LINE TRAFFIC ENGINEERING

    NARCIS (Netherlands)

    Fu, B.; Uhlig, S.P.W.G.

    The evaluation of dynamic Traffic Engineering (TE) algorithms is usually carried out using some specific network(s), traffic pattern(s) and traffic engineering objective(s). As the behavior of a TE algorithm is a consequence of the interactions between the network, the traffic demand and the algorit

  4. Genome-wide Identification of TCP Family Transcription Factors from Populus euphratica and Their Involvement in Leaf Shape Regulation.

    Science.gov (United States)

    Ma, Xiaodong; Ma, Jianchao; Fan, Di; Li, Chaofeng; Jiang, Yuanzhong; Luo, Keming

    2016-09-08

    Higher plants have been shown to experience a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase during its postembryonic development and distinct lateral organ morphologies have been observed at the different development stages. Populus euphratica, commonly known as a desert poplar, has developed heteromorphic leaves during its development. The TCP family genes encode a group of plant-specific transcription factors involved in several aspects of plant development. In particular, TCPs have been shown to influence leaf size and shape in many herbaceous plants. However, whether these functions are conserved in woody plants remains unknown. In the present study, we carried out genome-wide identification of TCP genes in P. euphratica and P. trichocarpa, and 33 and 36 genes encoding putative TCP proteins were found, respectively. Phylogenetic analysis of the poplar TCPs together with Arabidopsis TCPs indicated a biased expansion of the TCP gene family via segmental duplications. In addition, our results have also shown a correlation between different expression patterns of several P. euphratica TCP genes and leaf shape variations, indicating their involvement in the regulation of leaf shape development.

  5. Traffic Performance Analysis of Manet Routing Protocol

    CERN Document Server

    Rajeswari, S; 10.5121/ijdps.2011.2306

    2011-01-01

    The primary objective of this research work is to study and investigate the performance measures of Gossip Routing protocol and Energy Efficient and Reliable Adaptive Gossip routing protocols. We use TCP and CBR based traffic models to analyze the performance of above mentioned protocols based on the parameters of Packet Delivery Ratio, Average End-to-End Delay and Throughput. We will investigate the effect of change in the simulation time and Number of nodes for the MANET routing protocols. For Simulation, we have used ns-2 simulator.

  6. 轻量级嵌入式TCP/IP协议栈的设计%Design of Light-weight TCP/IP Stack in Embedded System

    Institute of Scientific and Technical Information of China (English)

    王力生; 梅岩; 曹南洋

    2007-01-01

    介绍了引入轻量级TCP/IP协议栈的背景,描述了标准TCP/IP协议栈,分析了嵌入式系统中TCP/IP协议栈的特点和设计的思路,总结了轻量级TCP/IP协议栈和标准TCP/IP协议栈的区别.

  7. Recent TCP(Tidal Current Power) projects in Korea

    Institute of Scientific and Technical Information of China (English)

    Chul; Hee; JO; Kang; Hee; LEE; Yu; Ho; RHO

    2010-01-01

    Having strong current on the west coast with up to 10 m tidal range in Korea,there are many suitable and applicable locations for TCP(Tidal Current Power) application in Korea.Not only the west coast,but also the south west regions having narrow channels between islands creating fast ocean stream are suitable for TCP.The first TCP application in Korea is 1 MW helical VAT(Vertical Axis Turbine) device installed in Wooldolmog area in 2008.The first HAT(Horizontal Axis Turbine) TCP device of 25 KW was developed and installed in cooling water weir of Samchonpo power plant in 2008.Furthermore,a 100 kW prototype HAT TCP device is being planned to be installed in Daebang strait in 2009.Another big project would be Inchon TCP farm of 200 MW on the west coast in Korea.The consortium of 5 members was formed in April,2009.This site will be the largest TCP site in the world.The paper describes recent TCP projects in Korea with background and environmental conditions of the projects.

  8. RATE-ADJUSTMENT ALGORITHM FOR AGGREGATE TCP CONGESTION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    P. TINNAKORNSRISUPHAP, ET AL

    2000-09-01

    The TCP congestion-control mechanism is an algorithm designed to probe the available bandwidth of the network path that TCP packets traverse. However, it is well-known that the TCP congestion-control mechanism does not perform well on networks with a large bandwidth-delay product due to the slow dynamics in adapting its congestion window, especially for short-lived flows. One promising solution to the problem is to aggregate and share the path information among TCP connections that traverse the same bottleneck path, i.e., Aggregate TCP. However, this paper shows via a queueing analysis of a generalized processor-sharing (GPS) queue with regularly-varying service time that a simple aggregation of local TCP connections together into a single aggregate TCP connection can result in a severe performance degradation. To prevent such a degradation, we introduce a rate-adjustment algorithm. Our simulation confirms that by utilizing our rate-adjustment algorithm on aggregate TCP, connections which would normally receive poor service achieve significant performance improvements without penalizing connections which already receive good service.

  9. Analysis of two competing TCP/IP connections

    NARCIS (Netherlands)

    Altman, E.; Jiménez, T.; Núñez Queija, R.

    2001-01-01

    Many mathematical models exist for describing the behavior of TCP/IP under an exogenous loss process that does not depend on the window size. The goal of this paper is to present a mathematical analysis of two asymmetric competing TCP connections where loss probabilities are directly related to thei

  10. Optimising TCP for cloud-based mobile networks

    DEFF Research Database (Denmark)

    Artuso, Matteo; Christiansen, Henrik Lehrmann

    2016-01-01

    protocols should therefore be adjusted to cope with the peculiarities of these networks. In this paper, we investigate an optimized design of the Transmission Control Protocol (TCP), as it plays a central role in all-IP mobile networks to ensure optimal performances for application-layer services. TCP...

  11. Passive TCP Reconstruction and Forensic Analysis with tcpflow

    Science.gov (United States)

    2013-09-01

    the libnids interface, allow- ing direct comparison of speed and accuracy of the two passive TCP implementations. We plan to publish a set of pcap...packet hashes to prevent TCP retransmit overwrite attacks, March 3 2009. US Patent 7500264. [13] H. Hibshi, T. Vidas , and L. Cranor. Usability of forensics

  12. Transformation and biodegradation of 1,2,3-trichloropropane (TCP)

    NARCIS (Netherlands)

    Samin, Ghufrana; Janssen, Dick B.

    2012-01-01

    1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen. It is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture. In view of the spread of TCP via groundwater and its toxicity, there is a need for

  13. Microwave sintering of nano size powder β-TCP bioceramics

    Directory of Open Access Journals (Sweden)

    Mirhadi B.

    2014-01-01

    Full Text Available A nano sized beta tricalcium phosphate (β-TCP powder was conventional sintered (CS and microwave sintered (MW, in order to obtain dense β-TCP ceramics. In this work the effect of microwave sintering conditions on the microstructure, phase composition and mechanical properties of materials based on tricalcium phosphate (TCP was investigated by SEM (scanning electron microscopyand XRD(X-ray diffraction and then compared with conventional sintered samples. Nano-size β-TCP powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of submicrometre β-TCP powder in situ. The β-TCP samples microwave (MW sintered for 15 min at 1100°C, with average grain size of 3μm, showed better densification, higher density and certainly higher hardness than samples conventionally sintered for 2 h at the same temperature. By comparing sintered and MW sintered β-TCP samples, it was concluded that MW sintered β-TCP samples have superior mechanical properties.

  14. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    Science.gov (United States)

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  15. Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach

    Science.gov (United States)

    Scott, Keith; Czetty, Stephen

    1998-01-01

    Various issues associated with "Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach" are presented in viewgraph form. Specific topics include: 1) TCP over mobile satellite links; 2) ways of breaking the control loop at the groundstation; 3) ACK implementation; and 4) ACK performance.

  16. Genome-wide analysis of TCP family in tobacco.

    Science.gov (United States)

    Chen, L; Chen, Y Q; Ding, A M; Chen, H; Xia, F; Wang, W F; Sun, Y H

    2016-05-23

    The TCP family is a transcription factor family, members of which are extensively involved in plant growth and development as well as in signal transduction in the response against many physiological and biochemical stimuli. In the present study, 61 TCP genes were identified in tobacco (Nicotiana tabacum) genome. Bioinformatic methods were employed for predicting and analyzing the gene structure, gene expression, phylogenetic analysis, and conserved domains of TCP proteins in tobacco. The 61 NtTCP genes were divided into three diverse groups, based on the division of TCP genes in tomato and Arabidopsis, and the results of the conserved domain and sequence analyses further confirmed the classification of the NtTCP genes. The expression pattern of NtTCP also demonstrated that majority of these genes play important roles in all the tissues, while some special genes exercise their functions only in specific tissues. In brief, the comprehensive and thorough study of the TCP family in other plants provides sufficient resources for studying the structure and functions of TCPs in tobacco.

  17. Traffic Infrastructure in the Development of the Croatian Traffic System

    Directory of Open Access Journals (Sweden)

    Damir Šimulčik

    2012-10-01

    Full Text Available The absence of a long-term traffic policy and of the policyof financing the constntction and maintenance of traffic infrastructurefacilities, represents a synthesis of numerous unresolvedrelations whose negative effects are felt in the overalleconomic and traffic development and consequently theevaluation of national potentials in the field. Adverse aspectcaused by the lack of a clear and feasible policy of financing thetraffic infrastructure facilities, is also a result of not having definedan adequate traffic policy, programme and strategiccourses of development, nor financing models that would be inaccordance with the market and economy system.This indicates that it is necessary to determine a policy forfinancing the constntction and maintenance of traffic infrastntcture,which has to be based on scientific development,team work, availability of plans and programmes to scientistsand experts, determined methodology based on marketing andeconomic logic in defining the programme and strategic tasksand assignments so as to make them feasible.In the near future, intensive preparations for investments inthe overall traffic sysiem are necessary, especially regarding thetraffic infrastntcture facilities - the pivotal points in the processof evaluating the traffic in our national tenitory. Croatia needsto define clearly its strategy in constructing and maintaining thegeneral traffic infrastructure, appointing at the same time thosewho will carry out the given tasks.

  18. Chitosan Fibers Modified with HAp/β–TCP Nanoparticles

    Directory of Open Access Journals (Sweden)

    Dariusz Wawro

    2011-10-01

    Full Text Available This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp, tricalcium phosphate (β-TCP, and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis and nanoparticles of tricalcium phosphate (β-TCP and hydroxyapatite (HAp suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.

  19. Novel evaluation method of TCP performance over satellite links

    Institute of Scientific and Technical Information of China (English)

    Wang Lina; Gu Xuemai

    2006-01-01

    A novel and efficient method to evaluate the transmission control protocol (TCP) performance over satellite links is presented. A TCP module is divided into three functional blocks, namely data processing, congestion control and error control. The re-established TCP module is easy to update TCP congestion control strategy or error control strategy. With the proposed analysis approach, the interactions between different congestion control and error control mechanisms, as well as the performance of various combination protocols in satellite environments have been investigated. Simulation results obtained through a series of experiments have shown that SNACK-based error control strategy can perform well with any other congestion control strategy. The best performance can be achieved by TCP New Reno congestion control strategy and SNACK-based error control strategy.

  20. Enhancing the Flexibility of TCP in Heterogeneous Network.

    Science.gov (United States)

    Hui, Wang; Peiyu, Li; Zhihui, Fan; Zheqing, Li; Xuhui, Wei

    Due to a set of constant initial values, the performance of conventional TCP drops significantly encountering heterogeneous network, showing low throughput and unfairness. This paper firstly demonstrates the chaotic character of TCP congestion control in heterogeneous network, especially the sensitivity to initial value. Inspired by merit of nature-inspired algorithm, a novel structure of TCP congestion control (IPPM, Internet Prey-Predator Model) is proposed. Parameters such as available link capacity(C), congestion window (W) and queue length (Q) are collected by IPPM, which calculates the max value of C according to the interacting relationship existing in C, W and Q, and IPPM initiates the TCP ssthresh with the calculated value. Plenty of simulation results show that the modified TCP can effectively avoid network congestion and packet loss. Besides, it holds high resource utilization, convergence speeds, fairness and stability.

  1. REAL TIME TCP/IP CONTROL OF MODULAR PRODUCTION SYSTEMS WITH FPGAS

    Directory of Open Access Journals (Sweden)

    A. Castillo-Atoche

    2007-04-01

    Full Text Available The Modular Production System (MPS can be used to reproduce nearly any function in complex manufacturing processes. In this work a different way of real time TCP/IP control of three different MPS controlled by embedded processors inside a FPGA is proposed. The digital design with FPGA is particularly advantageous due to its parallel processing made possible by its flexible structure, high integration and velocity. The TCP/IP control is carried out with a Rabbit Core microprocessor. This device contains the functions required to implement a web server allowing the remote control of the MPS. A user enters a public IP direction on a designed web page to enable/disable each independent manufacturing process.

  2. Active Queue Management in TCP Networks Based on Fuzzy-Pid Controller

    Directory of Open Access Journals (Sweden)

    Hossein ASHTIANI

    2012-01-01

    Full Text Available We introduce a novel and robust active queue management (AQM scheme based on a fuzzy controller, called hybrid fuzzy-PID controller. In the TCP network, AQM is important to regulate the queue length by passing or dropping the packets at the intermediate routers. RED, PI, and PID algorithms have been used for AQM. But these algorithms show weaknesses in the detection and control of congestion under dynamically changing network situations. In this paper a novel Fuzzy-based proportional-integral derivative (PID controller, which acts as an active queue manager (AQM for Internet routers, is proposed. These controllers are used to reduce packet loss and improve network utilization in TCP/IP networks. A new hybrid controller is proposed and compared with traditional RED based controller. Simulations are carried out to demonstrate the effectiveness of the proposed method and show that, the new hybrid fuzzy PID controller provides better performance than random early detection (RED and PID controllers

  3. Performance analysis of WWW traffic over a DQDB network

    Science.gov (United States)

    Hrasnica, Halid; Mueller, Thorsten; Lehnert, Ralf

    1999-08-01

    We present a simulation study of WWW traffic over a DQDB network running the TCP/IP protocol stack. All network and protocol elements have been implemented in detail. A realistic DQDB network with 12 nodes and 24 access units is studied. QoS parameters of 552 TCP connections between end users are analyzed. Our traffic source model and its parameters has been chosen according to the characteristics of typical WWW traffic. We have analyzed several network models with different kinds of buffer management in the DQDB access unit. The influence of the buffer management on QoS parameters and transmission performance has been examined. In this paper we describe and compare the results of our investigations for two types of the access unit; with separate buffer management and with shared buffer management. Simulation results for the throughput of the DQDB busses and the loss of IP packets in the DQDB network are given. TCP throughput and transmission times at two protocol levels are measured. Our results show a good utilization of the DQDB network for both types of access units studied.

  4. Cyclists' Injuries in Traffic

    Directory of Open Access Journals (Sweden)

    Eduard Missoni

    2004-01-01

    Full Text Available Among numerous participants in road traffic there are alsothe cyclists. Cycling has become during the recent years one ofthe major components of the modem living, even in Croatia. Inalmost all the developed countries of the world, cycling isemphasised as an activity which improves health and contributesto the improvement of overall physical fitness and environmentalprotection. During the period between 1 January 1996and 31 December 1999, an analysis of the number of cyclist accidentsin road traffic was carried out. Special attention waspaid to the number of injured cyclists. In 1996, in road traffic,there were 1,218 cyclist accidents in which 912 (74.9% cyclistswere injured. In 1997, there were 1,146 incidents and accidents,with 854 (74.5% injured persons. In 1998, there were 1,167accidents, 887 (76.0% injured. In the last study in 1999, thetotal number of cyclist accidents amounted to 1,230, and thenumber of the injured cyclists was 924 (75.1% .Every event resulting in a more or less severe disability is agreat distress and great damage to every injured person as individualas well as for the family and eventually for the society asa whole. This paper recommends certain measures and proceduresthat should substantially reduce the traffic accidents andincidents which involve cyclists.

  5. TCP/IP Over SpaceWire

    Science.gov (United States)

    Mills, S.; Parkes, S.

    The SpaceWire standard defines a network designed for handling payload data and control information onboard a spacecraft. Among the goals of SpaceWire are re-usability and reliability. The use of network protocols on top of SpaceWire is expected to enhance the already rich re-usability and reliability characteristics of SpaceWire. The Space Systems Research Group at the University of Dundee have developed software to allow data to be sent over SpaceWire using standard network protocols such as TCP/IP, as part of a program of work looking at network protocols for SpaceWire. This paper describes network protocols and their relationship to SpaceWire, introduces software written to allow network protocols to be layered on to SpaceWire, describes the research behind the development of this software, and gives results of some tests and observations made using the software.

  6. Traffic Dynamics of Computer Networks

    CERN Document Server

    Fekete, Attila

    2008-01-01

    Two important aspects of the Internet, namely the properties of its topology and the characteristics of its data traffic, have attracted growing attention of the physics community. My thesis has considered problems of both aspects. First I studied the stochastic behavior of TCP, the primary algorithm governing traffic in the current Internet, in an elementary network scenario consisting of a standalone infinite-sized buffer and an access link. The effect of the fast recovery and fast retransmission (FR/FR) algorithms is also considered. I showed that my model can be extended further to involve the effect of link propagation delay, characteristic of WAN. I continued my thesis with the investigation of finite-sized semi-bottleneck buffers, where packets can be dropped not only at the link, but also at the buffer. I demonstrated that the behavior of the system depends only on a certain combination of the parameters. Moreover, an analytic formula was derived that gives the ratio of packet loss rate at the buffer ...

  7. Treatment of periodontal intrabony defects using β-TCP alone or in combination with rhPDGF-BB: a randomized controlled clinical and radiographic study.

    Science.gov (United States)

    Maroo, Sneha; Murthy, K Raja V

    2014-01-01

    The need to increase the predictability of periodontal regeneration has encouraged clinicians and researchers to employ cell-stimulating proteins in combination with osteoconductive scaffolds, based on the principles of tissue engineering. The purpose of this clinical and radiographic study was to compare the regenerative potential of the combination of β-tricalcium phosphate (β-TCP) and recombinant human platelet-derived growth factor BB (rhPDGF-BB) in the grafting of intraosseous defects with the established technique of bone grafting with (β-TCP alone. A total of 30 sites from 15 patients with infrabony defects in two different quadrants were selected, and the sites were randomly divided into test sites (rhPDGF + β-TCP) and control sites (β-TCP alone) using a split-mouth design. Clinical parameters, including probing pocket depth, clinical attachment level, and gingival recession, were recorded at baseline, 6 months, and 9 months. Radiographic evaluation was carried out to evaluate defect fill, change in alveolar crest height, and percentage of defect fill at baseline, 6 months, and 9 months. Both the experimental groups showed statistically significant reduction in probing pocket depth and gain in clinical attachment level. On intergroup comparison, sites treated with rhPDGF + β-TCP demonstrated a significantly greater pocket depth reduction (P TCP-treated sites demonstrated a significant gain in mean alveolar crest height at 6 and 9 months (P TCP-treated sites demonstrated crestal resorption. Both groups demonstrated potential in enhancing periodontal regeneration; however, on comparison between the two groups, the results obtained by rhPDGF + β-TCP were significantly better with respect to both clinical and radiographic parameters.

  8. A Novel Wireless TCP and its Steady State Throughput Model

    Institute of Scientific and Technical Information of China (English)

    YAO Ling; JI Hong; YUE Guang-xin

    2004-01-01

    Unlike wired networks, random packet loss due to bit errors may cause significant performance degradation of Transmission Control Protocol (TCP). We propose and study a novel end-to-end congestion control mechanism called TCP-LD (Loss Detection) that is simple and effective for dealing with random packet loss. We also give its steady state throughput model. Both the ns2 and numerical simulation results show that our scheme can achieve significant throughput improvements without adversely affecting other concurrent TCP connections, including other concurrent Reno connections both in wired and wireless environment.

  9. Release Kinetics and Antibacterial Efficacy of Microporous β-TCP Coatings

    Directory of Open Access Journals (Sweden)

    Michael Seidenstuecker

    2013-01-01

    Full Text Available Purpose. The aim of this study was to impregnate microporous β-TCP scaffolds with different antibiotic solutions and to determine their release behavior. Materials and Methods. We impregnated a β-TCP scaffold with antibiotics by using three methods: drop, dip, and stream coating with 120 mg/mL of antibiotic solution. After drying for 72 h at 37°C, 2 mL of distilled water was added to the antibiotic-coated plugs and incubated at 37°C. After defined time points (1, 2, 3, 6, 9, and 14 days, the liquid was completely replaced. The extracted liquid was analyzed by capillary zone electrophoresis and the Kirby Bauer disc diffusion test. For statistical analysis, we calculated a mean and standard deviation and carried out an analysis of variance using ANOVA. Results. The VAN and CLI release from the β-TCP scaffolds was rapid, occurring within 24 h with 89 ± 0.8% VAN and 90.4 ± 1.5% CLI regardless of the type of insulation. After six days, the VAN and CLI were completely released. All samples taken at later time points had a VAN or CLI concentration below the detection limit of 4 µg/mL. The released amounts of VAN and CLI within the first three days revealed antimicrobial activity.

  10. In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

    Institute of Scientific and Technical Information of China (English)

    Dali ZHOU; Weizhong YANG; Guangfu Yin; Changqiong ZHENG; Yun ZHANG; Huaiqing CHEN; Rui CHEN

    2004-01-01

    To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, I.e. Solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. Weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size ofβ-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.

  11. TO IMPROVE THE TCP PERFORMANCE USING CROSS LAYER IN WIRED CUM WIRELESS NETWORK.

    Directory of Open Access Journals (Sweden)

    KANNADASAN. R

    2012-04-01

    Full Text Available Recent development mostly based on the high speed internet access of large amount of data at any time over wireless network. Packets loss can also occur due to link failure in wired cum wireless environment. To reduce the loss rate, packet delay, retransmission time, Wi-Max is proposed with cross layer design. In this paper, to improve the performance TCP in the WI-MAX flow its estimating bandwidth of the each packet, reduce the RTT in retransmission which gives more data transfer rate and also reduce the packet drop ratio. Some layers are merging their functions and provide traffic flow with ARQ in Wi-Max. Each node provides information through Access Point which can uplink and downlink feedback about packet as an ACK or NACK. Retransmission mechanism is used for NACK to resend the lost frame through the access point.

  12. TCP Congestion Control for the Networks with Markovian Jump Parameters

    Directory of Open Access Journals (Sweden)

    MOMENI, H. R.

    2011-05-01

    Full Text Available This paper is concerned with the problem of TCP congestion control for the class of communication networks with random parameters. The linear dynamic model of TCP New Reno in congestion avoidance mode is considered which contains round trip delays in both state and input. The randomness of link capacity, round trip time delay and the number of TCP sessions is modeled with a continuous-time finite state Markov process. An Active Queue Management (AQM technique is then used to adjust the queue level of the congested link to a predefined value. For this purpose, a dynamic output feedback controller with mode dependent parameters is synthesized to stochastically stabilize the TCP/AQM dynamics. The procedure of the control synthesis is implemented by solving a linear matrix inequality (LMI. The results are tested within a simulation example and the effectiveness of the proposed design method is verified.

  13. Mixing TCP and Satellites: A View from Above

    Science.gov (United States)

    Travis, Eric

    1998-01-01

    Various issues associated with "Mixing TCP and Satellites: A View from Above" are presented in viewgraph form. Specific topics include: 1) Why are open protocol standards important?; and 2) Protocols are like galoshes: One size does not fit all.

  14. Optimization of the transmission mechanism for wireless TCP

    Institute of Scientific and Technical Information of China (English)

    QU Zhao-wei; ZHANG Juan

    2008-01-01

    A novel method which can detect the possible handoffsfor mobile nodes is proposed in this article. The method can bedeployed on mobile nodes. So when a possible handoff occurs,mobile nodes can detect and take some necessary actions intime. In this study, the method is also used to optimize thetransmission mechanism of Q-TCP. Moreover, the simulationresults show that Q-TCP can provide better quality of service(QoS) for mobile nodes when they are moving among differentagents.

  15. TCP I-Vegas in Mobile-IP Network

    Directory of Open Access Journals (Sweden)

    Nitin Jain

    2014-01-01

    Full Text Available Mobile Internet Protocol (Mobile-IP or MIP provides hosts with the ability to change their point of attachment to the network without compromising their ability to communicate. However, when TCP Vegas is used over a MIP network, its performance degrades because it may respond to a handoff by invoking its congestion control algorithm. TCP Vegas is sensitive to the change of Round-Trip Time (RTT and it may recognize the increased RTT as a result of network congestion. This is because TCP Vegas could not differentiate whether the increased RTT is due to route change or network congestion. This paper presents a new and improved version of conventional TCP Vegas, which we named as TCP I-Vegas (where “I”, stands for Improved. Vegas performs well when compared to Reno but when sharing bandwidth with Reno its performance degrades. I-Vegas has been designed keeping in mind that whenever TCP variants like Reno has to share the bandwidth with Vegas then instead of using Vegas, if we use I-Vegas then the loss which Vegas would have to bear will not be more. We compared the performance of I-Vegas with Vegas in MIP environment using Network Simulator (NS-2. Simulation results show that I-Vegas performs better than Vegas in terms of providing better throughput and congestion window behavior.

  16. 开放的MODBUS TCP (连载二)

    Institute of Scientific and Technical Information of China (English)

    华镕

    2005-01-01

    @@ 1为什么要用TCP/IP? TCP/IP ( Transmission Control Protocol / Intemet Protocol,传送控制协议/网际协议)之所以强大的最主要的一个原因在于它可以使用在多种物理网络技术上,包括局域网和广域网技术,并能适应几乎所有的底层通信技术.20世纪80年代初,先在X.25上运行TCP/IP协议,而后,又在一个拨号语音网络(例如电话系统)上使用TCP/IP协议,又有TCP/IP在令牌环网上运行成功,最后,又实现了TCP/IP远程分组无线网点与其他Intemet网点之间进行TCP/IP的通信.

  17. TCP Packet Trace Analysis. M.S. Thesis

    Science.gov (United States)

    Shepard, Timothy J.

    1991-01-01

    Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

  18. Biological Evaluation of α-TCP/TTCP Composite Bone Cement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    α-tricalcium phosphate(α-TCP)/tetracalcium phosphate(TTCP) composite bone cement had good hydration characteristic.In our system,α-TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g*mL-1.The setting time could be adjusted,the maximum compressive strength was 45.36MPa,and the hydration product was hydroxyapatite (HAP).In vitro biological simulated experiments indicate that α-TCP/TTCP bone cement has α certain dissolubility.The hardened product is mainly HAP after soaking in simulated body fluid (SBF) for 10 weeks.The results of in vitro test and animal experiments and SEM analyses show that no local or general toxicity response,no muscle stimulation,no haemolysis,no cruor,no inflammatory reaction and no exclusion response are caused by α-TCP/TTCP cement, which can be contributed to bone tissue spreading and impinging.α-TCP/TTCP cement hydrated and hardened continually in vivo.The materials fused with host bone together with implanting time prolonging.Therefore,it is believed that α-TCP/TTCP composite bone cement has a high biocompatibility and bioactivity,a certain biodegradation and good osteogenesis as well.

  19. Study of dynamical properties in β-Tcp/Ch layers

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A.; Caicedo, J. C. [Universidad del Valle, Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Cali, Valle del Cauca (Colombia); Aperador, W., E-mail: jacaicedoangulo1@gmail.com [Universidad Militar Nueva Granada, Departamento de Ingenieria, 80 Entrada A La KR11 No. 101, Bogota (Colombia)

    2015-07-01

    β-Tricalcium phosphate/Chitosan (β-Tcp/Ch) coatings were deposited on 316l stainless steel (316l Ss) substrates by a cathodic electrodeposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-ray diffraction, and the results indicated that the crystallographic structure of β-Tcp was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy and atomic force microscopy showed the root-mean squares hardness of the β-Tcp/Ch coatings decreased by further increasing chitosan percentage. The elastic-plastic characteristics of the coatings were determined by conducting nano indentation test, indicating that the increase if chitosan percentage is directly related to increasing the hardness and elastic modulus of the β-Tcp/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear the β-Tcp/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-Tcp/Ch coatings as a function of increasing of the chitosan percentage. (Author)

  20. Wide-area traffic: The failure of Poisson modeling

    Energy Technology Data Exchange (ETDEWEB)

    Paxson, V.; Floyd, S.

    1994-08-01

    Network arrivals are often modeled as Poisson processes for analytic simplicity, even though a number of traffic studies have shown that packet interarrivals are not exponentially distributed. The authors evaluate 21 wide-area traces, investigating a number of wide-area TCP arrival processes (session and connection arrivals, FTPDATA connection arrivals within FTP sessions, and TELNET packet arrivals) to determine the error introduced by modeling them using Poisson processes. The authors find that user-initiated TCP session arrivals, such as remote-login and file-transfer, are well-modeled as Poisson processes with fixed hourly rates, but that other connection arrivals deviate considerably from Poisson; that modeling TELNET packet interarrivals as exponential grievously underestimates the burstiness of TELNET traffic, but using the empirical Tcplib[DJCME92] interarrivals preserves burstiness over many time scales; and that FTPDATA connection arrivals within FTP sessions come bunched into ``connection bursts``, the largest of which are so large that they completely dominate FTPDATA traffic. Finally, they offer some preliminary results regarding how the findings relate to the possible self-similarity of wide-area traffic.

  1. The Method of Winsock Network Program Based on TCP/IP Protocol%基于TCP/IP协议的WinSock网络程序方法

    Institute of Scientific and Technical Information of China (English)

    任泰明

    2002-01-01

    TCP/IP协议是Internet网络所使用的协议,设计基于TCP/IP的网络程序是Windows程序设计中难点,本文对基于TCP/IP协议的网络程序设计原理、方法和步骤进行了分析和说明.

  2. Highway Traffic Safety Manpower Functions Guide.

    Science.gov (United States)

    Daugherty, Ronald D.; And Others

    The purpose of the project, "Revision and Update of Traffic Safety Manpower Training Program Development Guide," was to develop the HIGHWAY TRAFFIC SAFETY MANPOWER FUNCTIONS GUIDE. This document provides an organizational schema illustrating the functions essential to be performed and the interrelationship of these functions to carry out…

  3. Principle and prevention of TCP SYN Flood attack%TCP SYN Flood攻击的原理与防范

    Institute of Scientific and Technical Information of China (English)

    吴华光; 甘燕玲

    2005-01-01

    保证网络安全是网络技术正常发展和网络的正常运行的重要研究方向,通过讨论TCP三次握手的缺陷和TCP SYN Flood攻击的基本原理,探讨防御TCP SYN Flood攻击可以采取的措施.

  4. A Survey of TCP Reno, New Reno and Sack Over Mobile Ad-Hoc Network

    CERN Document Server

    Khan, Md Nazmul Islam; Aziz, Md Tariq

    2012-01-01

    Transmission Control Protocol (TCP) is often preferred to be implemented at the transport layer of a Mobile Ad-hoc Network (MANET) because of its wide range of applications, which enjoys the advantage of reliable data transmission in the Internet. However, because of some unique characteristics of MANET, TCP cannot offer reliable services while using e-mail, internet search and file transmission in such a network. The research investigates how well the different versions of TCP respond to various performance differentials when subjected to different network stresses and topology changes, aside from identifying the most efficient and robust TCP version(s) for different MANET scenarios. Among several TCP variants, three types are considered important for the analysis, namely TCP Reno, TCP New Reno and TCP Selective Acknowledgment (SACK). In most cases, the TCP performance is found in our study to decrease when the node size and mobility rate is increased in the network. There is, however, exception to this. As ...

  5. Effects of added ZnTCP on mechanical and biological properties of apatite cement

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K.; Suzuki, K. [Okayama Univ. Dental School (Japan). Dept. of Biomaterials; Miyamoto, Y.; Toh, T.; Yuasa, T.; Nagayama, M. [Tokushima Univ. (Japan). First Dept. of Oral and Maxillofacial Surgery; Ito, A. [National Inst. for Advanced Interdisciplinary Research, MITT, Ibaragi (Japan)

    2001-07-01

    Effects of added Zn doped {beta}-tricalcium phosphate (ZnTCP) on mechanical and biological properties of apatite cement (AC) was studied. Powder X-ray diffractometer revealed that ZnTCP shows no reactivity with AC. The mechanical strength of AC decreased increasing amounts of added ZnTCP. We observed no effect on the setting time of AC when the amount of ZnTCP was 10% or less. Proliferation of the osteoblastic cells was significantly increased on the surface of AC containing 5% ZnTCP when compared with that containing no ZnTCP. In contrast, proliferation of the cells decreased on the surface of AC containing 10% ZnTCP when compared with that free from ZnTCP; indicating cytotoxity. We concluded therefore, that addition of ZnTCP to AC might be useful to enhance the osteoconductivity of AC when release of Zn{sup 2+} can be carefully regulated. (orig.)

  6. Development of River Traffic in the Traffic System of Central Croatia

    Directory of Open Access Journals (Sweden)

    Dragan Badanjak

    2006-05-01

    Full Text Available From the aspect of public transport of passengers andgoods, the traffic system in Central Croatia consists of road,rail, air and river subsystems. Regarding their share in the volumeof passenger and cargo transport as well as the carried outtransport operations in the traffic system of Central Croatia,road and rail traffic are the dominant traffic subsystems. Regardingits technical, technological, organizational and economicindicators, the river traffic system represents the less developedsubsystem of the traffic system of Central Croatia, andthe situation in this respect is not much different at the nationallevel either.The possibilities for the development of river traffic systemhave not been sufficiently used, although the potential trafficdemand for the transportation services are substantial, especiallywhen considering the river Sava which potentially offersa direct connection to the trunk European waterway. The advantagesof the Central Croatian location undoubtedly lie inthe traffic and geo-strategic position, but the value of this locationcan be used only then when the quality level of the trafficsystem and the construction level of the infrastructurecatch up with the ones in the developed European countries.The conditions for the traffic development are first of allstrong and daily faster changes in the strata, especially regardingthe implementation of new solutions and increasing theefficiency of the overall traffic system. It is precisely for thisreason that special interest should be to study the traffic valuesaccording to the available data, establish their possiblerules as function of time, and design appropriate mathematicalmodels with the aim of forecasting the traffic developmentin the future.

  7. The Optimal Dispatch of Traffic and Patrol Police Service Platforms

    Directory of Open Access Journals (Sweden)

    Ke Quan Zhao

    2012-01-01

    Full Text Available The main goal of this paper is to present a minmax programming model for the optimal dispatch of Traffic and Patrol Police Service Platforms with single traffic congestion. The objective is to minimize the longest time of the dispatch for Traffic and Patrol Police Service Platforms. Some numerical experiments are carried out, and the optimal project is given.

  8. Analyzing and evaluating the three-line rail traffic

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, we propose a method to simulate the three-line rail traffic. The aim is to evaluate the carrying capacity of the three-line rail traffic by studying the rail traffic flow when the passenger flow is unsymmetrical. The simulation results demonstrate that under the unsymmetrical condition, the three-line rail traffic system has almost the same carrying capacity as that of a four-line rail traffic system. Compared with the four-line rail traffic system, the three-line rail traffic system has better utilization of rail line. As a result, building the three-line rail traffic system is a more economical and rational selection.

  9. Analyzing and evaluating the three-line rail traffic

    Institute of Scientific and Technical Information of China (English)

    GAO ZiYou; ZHOU HuaLiang; LI KePing; NING Bing; TANG Tao

    2008-01-01

    In this paper,we propose a method to simulate the three-line rail traffic.The aim is to evaluate the carrying capacity of the three-line rail traffic by studying the rail traffic flow when the passenger flow is unsymmetrical.The simulation results demonstrate that under the unsymmetrical condition,the three-line rail traffic sys-tem has almost the same carrying capacity as that of a four-line rail traffic system.Compared with the four-line rail traffic system,the three-line rail traffic system has better utilization of rail line.As a result,building the three-line rail traffic system is a more economical and rational selection.

  10. A Novel Congestion Detection Scheme in TCP Over OBS Networks

    KAUST Repository

    Shihada, Basem

    2009-02-01

    This paper introduces a novel congestion detection scheme for high-bandwidth TCP flows over optical burst switching (OBS) networks, called statistical additive increase multiplicative decrease (SAIMD). SAIMD maintains and analyzes a number of previous round-trip time (RTTs) at the TCP senders in order to identify the confidence with which a packet loss event is due to network congestion. The confidence is derived by positioning short-term RTT in the spectrum of long-term historical RTTs. The derived confidence corresponding to the packet loss is then taken in the developed policy for TCP congestion window adjustment. We will show through extensive simulation that the proposed scheme can effectively solve the false congestion detection problem and significantly outperform the conventional TCP counterparts without losing fairness. The advantages gained in our scheme are at the expense of introducing more overhead in the SAIMD TCP senders. Based on the proposed congestion control algorithm, a throughput model is formulated, and is further verified by simulation results.

  11. TCP-Adaptive in High Speed Long Distance Networks

    Directory of Open Access Journals (Sweden)

    Quan Liu

    2014-02-01

    Full Text Available With the development of high performance computing and increasing of network bandwidth, more and more applications require fast data transfer over high-speed long-distance networks. Research shows that the standard TCP Reno cannot fulfill the requirement of fast transfer of massive data due to its conservative congestion control mechanism. Some works have been proposed to improve the TCP throughput performance using more aggressive window increasing tactics and obtain substantial achievements. However, they cannot be strictly proved to be comprehensively suitable for high-speed complex network environments. In this paper, we propose TCP-Adaptive, an adaptive congestion control algorithm adjusting the increasing congestion window dynamically. The algorithm improves logarithmic detection procedure for available bandwidth in the flow path by distinguishing the first detection in congestion avoidance and retransmission timeout. On the other hand, an adaptive control algorithm is proposed to achieve better performance in high-speed long-distance networks. The algorithm uses round trip time (RTT variations to predict the congestion trends to update the increments of congestion window. Simulations verify the property of TCP-Adaptive and show satisfying performance in throughput, RTT fairness aspects over high-speed long-distance networks. Especially in sporadic loss environment, TCP-Adaptive shows a significant adaptability with the variations of link quality

  12. Experimental Evaluation of TCP and ICMP in Network Measurement

    Institute of Scientific and Technical Information of China (English)

    LI Wen-wei; ZHANG Da-fang; XIE Gao-gang; YANG Jin-ming

    2005-01-01

    Network measurement is an important approach to understand network behaviors, which has been widely studied. Both Transfer Control Protocol (TCP) and Internet Control Messages Protocol (ICMP) are applied in network measurement, while investigating the differences between the measured results of these two protocols is an important topic that has been less investigated. In this paper, to compare the differences between TCP and ICMP when they are used in measuring host connectivity, RTT, and packet loss rate, two groups of comparison programs have been designed, and after careful evaluation of the program parameters, a lot of comparison experiments are executed on the Internet. The experimental results show that, there are significant differences between the host connectivity measured using TCP or ICMP; in general, the accuracy of connectivity measured using TCP is 20%- 30% higher than that measured using ICMP. The case of RTT and packet loss rate is complicated, which are related to path loads and destination host loads. While commonly, the RTT and packet loss rate measured using TCP or ICMP are very close. According to the experimental results, some advices are also given on protocol selection for conducting accurate connectivity, RTT and packet loss rate measurements.

  13. On urban road traffic state evaluation index system and method

    Science.gov (United States)

    Su, Fei; Dong, Honghui; Jia, Limin; Sun, Xuan

    2017-01-01

    Traffic state evaluation is a basic and critical work in the research on road traffic congestion. It can provide basic data support for the improvement measures and information release in traffic management and service. The aim of this research is to obtain a comprehensive value to describe traffic state accurately based on the evaluation index system. In this paper, it is carried out using fuzzy c-means (FCM) algorithm and fuzzy entropy weight method. In the framework, traffic flow was classified into six different states to determine the fuzzy range of indices using the improved FCM clustering analysis. Besides, fuzzy entropy weight method is proposed to compute the evaluation result of traffic state for section, road and road network, respectively. The experiments based on the traffic information in a subset of Beijing’s road network prove that the findings of traffic evaluation are in accordance with the actual situation and people’s sense of traffic state.

  14. Chiba Tendril-Less locus determines tendril organ identity in melon (Cucumis melo L.) and potentially encodes a tendril-specific TCP homolog.

    Science.gov (United States)

    Mizuno, Shinji; Sonoda, Masatoshi; Tamura, Yayoi; Nishino, Eisho; Suzuki, Hideyuki; Sato, Takahide; Oizumi, Toshikatsu

    2015-11-01

    Tendrils are filamentous plant organs that coil on contact with an object, thereby providing mechanical support for climbing to reach more sunlight. Plant tendrils are considered to be modified structure of leaves, stems, or inflorescence, but the origin of cucurbit tendrils is still argued because of the complexity in the axillary organ patterning. We carried out morphological and genetic analyses of the Chiba Tendril-Less (ctl) melon (Cucumis melo) mutant, and found strong evidence that the melon tendril is a modified organ derived from a stem-leaf complex of a lateral shoot. Heterozygous (CTL/ctl) plants showed traits intermediate between tendril and shoot, and ontogenies of wild-type tendrils and mutant modified shoots coincided. We identified the CTL locus in a 200-kb region in melon linkage group IX. A single base deletion in a melon TCP transcription factor gene (CmTCP1) was detected in the mutant ctl sequence, and the expression of CmTCP1 was specifically high in wild-type tendrils. Phylogenetic analysis demonstrated the novelty of the CmTCP1 protein and the unique molecular evolution of its orthologs in the Cucurbitaceae. Our results move us closer to answering the long-standing question of which organ was modified to become the cucurbit tendril, and suggest a novel function of the TCP transcription factor in plant development.

  15. El alba-tcp mirado con buenos ojos

    Directory of Open Access Journals (Sweden)

    Christopher David Absell

    2012-01-01

    Full Text Available El surgimiento de la Alianza Bolivariana para los Pueblos de Nuestra América-Tratado de Comercio de los Pueblos (alba-tcp representa una novedad de importancia regional e internacional; sin embargo hasta la fecha el trabajo académico sobre la organización ha sido escaso y se ha caracterizado por tener un enfoque metodológico descriptivo carente de investigación empírica comprensiva. En este artículo sostengo que este enfoque metodológico ha imbuido la literatura de un sesgo positivo a favor del alba-tcp y sus proyectos de desarrollo. El objetivo de este artículo es examinar esta literatura para determinar una agenda de investigación para el estudio del alba-tcp.

  16. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  17. Cloning, expression and alternative splicing of the novel isoform of hTCP11 gene

    DEFF Research Database (Denmark)

    Ma, Yong-xin; Zhang, Si-zhong; Wu, Qia-qing;

    2003-01-01

    To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing.......To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing....

  18. TCP-Call Admission Control Interaction in Multiplatform Space Architectures

    Directory of Open Access Journals (Sweden)

    Georgios Theodoridis

    2007-06-01

    Full Text Available The implementation of efficient call admission control (CAC algorithms is useful to prevent congestion and guarantee target quality of service (QoS. When TCP protocol is adopted, some inefficiencies can arise due to the peculiar evolution of the congestion window. The development of cross-layer techniques can greatly help to improve efficiency and flexibility for wireless networks. In this frame, the present paper addresses the introduction of TCP feedback into the CAC procedures in different nonterrestrial wireless architectures. CAC performance improvement is shown for different space-based architectures, including both satellites and high altitude platform (HAP systems.

  19. Analogues between tuning TCP for Data Acquisition and Datacenter Networks

    CERN Document Server

    Jereczek, Grzegorz Edmund; The ATLAS collaboration

    2015-01-01

    A many-to-one communication pattern is present both in Data Acquisition (DAQ) and datacenter networks. The problem arising from this pattern is widely known in the literature as incast and can be observed as TCP throughput collapse. It is a result of overloading the switch buffers, when a specific node in a network requests data from multiple sources. This paper provides two contributions. First, we confirm that there are strong analogies between the TCP behavior in DAQ and datacenter networks. Second, we evaluate different proposals from datacenter for application in DAQ to improve performance and reduce buffer requirements.

  20. BIFURCATIONS AND CHAOS CONTROL IN TCP-RED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Internet is heterogeneous in nature,and ex-tremely wide variations in parametric perturbationlead to a very rich world of dynamical behaviorsranging from s mooth,stable operation to rathercomplicated irregular patterns.In[1],the occur-rence of chaotic behavior in TCP has been reportedfor the first ti me.Since the seminal work of Mathisand Floyd[2-3],there have been increasing interestsin the dynamical characteristics of Internet.In theprevious work,TCP congestion control algorithmplus RED queue management m...

  1. Internetworking with Internet Protocol (IP) and Transmission Control Protocol (TCP) within the Military

    OpenAIRE

    Eikenberg, Bruce R.

    1990-01-01

    Approved for public release; distribution is unlimited. The backbone of the internetworking technology widely used by the military, as well as many civilian installations, is commonly referred to as TCP/IP. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the two standard communication protocols from which TCP/IP receives its name. By utilizing TCP/IP, the majority of technical issues of interconnecting various computer technologies have become transparent to the user. Th...

  2. TRANSIMS traffic flow characteristics

    CERN Document Server

    Nagel, K; Pieck, M; Donnelly, R; Barrett, C L; Nagel, Kai; Stretz, Paula; Pieck, Martin; Donnelly, Rick; Barrett, Christopher L.

    1997-01-01

    Knowledge of fundamental traffic flow characteristics of traffic simulation models is an essential requirement when using these models for the planning, design, and operation of transportation systems. In this paper we discuss the following: a description of how features relevant to traffic flow are currently under implementation in the TRANSIMS microsimulation, a proposition for standardized traffic flow tests for traffic simulation models, and the results of these tests for two different versions of the TRANSIMS microsimulation.

  3. A Survey Of Tcp Reno, New Reno And Sack Over Mobile Ad-Hoc Network

    Directory of Open Access Journals (Sweden)

    Md Nazmul Islam Khan

    2012-02-01

    Full Text Available Transmission Control Protocol (TCP is often preferred to be implemented at the transport layer of a Mobile Ad-hoc Network (MANET because of its wide range of applications, which enjoys the advantage of reliable data transmission in the Internet. However, because of some unique characteristics of MANET, TCP cannot offer reliable services while using e-mail, internet search and file transmission insuch a network. The research investigates how well the different versions of TCP respond to various performance differentials when subjected to different network stresses and topology changes, aside from identifying the most efficient and robust TCP version(s for different MANET scenarios. Among several TCP variants, three types are considered important for the analysis, namely TCP Reno, TCP New Reno and TCP Selective Acknowledgment (SACK. In most cases, the TCP performance is found in our study to decrease when the node size and mobility rate is increased in the network. There is, however, exception to this. As our simulation results demonstrate, the increases in the node velocity sometimes help the TCP to attain a better performance. The study also reveals that out of the three variants, TCP SACK can adaptrelatively well to the changing network sizes while TCP Reno performs most robustly in the presence ofdifferent mobility rates within MANET.

  4. File list: Oth.Epd.20.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.20.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX019786,SRX663250,SRX6...X514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.20.TCP1.AllCell.bed ...

  5. File list: Oth.ALL.05.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663251,SRX663249...44,SRX663252,SRX105186,SRX514838,SRX018991,SRX277138,SRX105187,SRX277132,SRX099055 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.05.TCP1.AllCell.bed ...

  6. File list: Oth.Epd.10.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.10.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663251,SRX019786,SRX5...X105186,SRX514839,SRX514838,SRX099053 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.10.TCP1.AllCell.bed ...

  7. File list: Oth.ALL.20.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.20.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX019786,SRX663250...39,SRX514843,SRX018991,SRX277132,SRX212375,SRX514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.20.TCP1.AllCell.bed ...

  8. File list: Oth.Epd.50.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.50.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663250,SRX663252,SRX6...X514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.50.TCP1.AllCell.bed ...

  9. File list: Oth.ALL.50.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663250,SRX663252...43,SRX018992,SRX212375,SRX514838,SRX277135,SRX277132,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.50.TCP1.AllCell.bed ...

  10. File list: Oth.Epd.05.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.05.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663251,SRX663249,SRX6...X514838,SRX018991,SRX105187,SRX099055 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.05.TCP1.AllCell.bed ...

  11. File list: Oth.ALL.10.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.10.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663251,SRX019786...38,SRX277135,SRX018991,SRX105187,SRX099055,SRX105186,SRX514839,SRX514838,SRX099053 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.10.TCP1.AllCell.bed ...

  12. TCP-HY: Improving TCP Performance in Hybrid IP Network%TCP-HY:优化TCP在混合IP网络环境中的效率

    Institute of Scientific and Technical Information of China (English)

    徐航宇; 罗键

    2007-01-01

    在混合网络环境下,由于数据包传输的非时序性以及在传输过程中相对较高的误码率,TCP的传输效率极大地被降低了.对此,提出了一种新的TCP改进版本:TCP-HY,它能够有效解决数据包延迟以及高误码率的问题.试验表明,TCP-HY在混合网络环境中能够大大提高TCP的效率,充分利用有效带宽,是一种优秀的解决方案.

  13. TCP-IP Model in Data Communication and Networking

    Directory of Open Access Journals (Sweden)

    Pranab Bandhu Nath

    2015-10-01

    Full Text Available The Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP, because it’s most important protocols, the Transmission Control Protocol (TCP and the Internet Protocol (IP, were the first networking protocols defined in this standard. Often also called the Internet model, it was originally also known as the DoD model, because the development of the networking model was funded by DARPA, an agency of the United States Department of Defense. TCP/IP provides end-to-end connectivity specifying how data should be packetized, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved. From lowest to highest, the layers are the link layer, containing communication technologies for a single network segment (link; the internet layer, connecting hosts across independent networks, thus establishing internetworking; the transport layer handling host-to-host communication; and the application layer, which provides process-to-process application data exchange. Our aim is describe operation & models of TCP-IP suite in data communication networking

  14. Displaying digital video over ethernet TCP-IP

    Science.gov (United States)

    Foster, John; Jackson, Paul

    1994-04-01

    Transmission and playback of digital audio and video via TCP/IP has been successfully completed with the use of typical low-end UNIX workstations. In addition, attempts have been made to increase the frame rate by sending only sections of a frame that varied the most.

  15. Construction of a nuclear data server using TCP/IP

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko; Sakai, Osamu [Kyushu Univ., Fukuoka (Japan)

    1997-03-01

    We construct a nuclear data server which provides data in the evaluated nuclear data library through the network by means of TCP/IP. The client is not necessarily a user but a computer program. Two examples with a prototype server program are demonstrated, the first is data transfer from the server to a user, and the second is to a computer program. (author)

  16. Versatile Markovian models for networks with asymmetric TCP sources

    NARCIS (Netherlands)

    Foreest, van N.D.; Haverkort, B.R.; Mandjes, M.R.H.; Scheinhardt, W.R.W.

    2004-01-01

    In this paper we use Stochastic Petri Nets (SPNs) to study the interaction of multiple TCP sources that share one or two buffers, thereby considerably extending earlier work. We first consider two sources sharing a buffer and investigate the consequences of two popular assumptions for the loss proce

  17. Versatile Stochastic Models for Networks with Asymmetric TCP Sources

    NARCIS (Netherlands)

    Foreest, van Nicky D.; Haverkort, Boudewijn R.; Mandjes, Michel R.H.; Scheinhardt, Werner R.W.

    2007-01-01

    In this paper we use stochastic Petri nets (SPNs) to study the interaction of multiple TCP sources that share one or two buffers. No analytical nor numerical results have been presented for such cases yet. We use SPNs in an unconventional way: the tokens in the SPN do not represent the packets being

  18. SCPS-TP: A Satellite-Enhanced TCP

    Science.gov (United States)

    Scott, Keith; Torgerson, Leigh

    2004-01-01

    This viewgraph presentation reviews the Space Communications Protocol Standard Transport Protocol (SCPS-TP) which is a satellite enhanced Transport Control Protocol (TCP). The contents include: 1) Purpose; 2) Background; 3) Stressed Communication Environments; 4) SCPS-TP Features; 5) SCPS-TP Performance; 6) Performance Enhancing Proxies (PEPs); and 7) Ongoing and Future SCPS-TP Work.

  19. Ohio Medical Office Management. Technical Competency Profile (TCP).

    Science.gov (United States)

    Ray, Gayl M.; Wilson, Nick; Mangini, Rick

    This document provides a framework for a broad-based secondary and postsecondary curriculum to prepare students for employment in medical office management. The first part of the technical competency profile (TCP) contains the following items: an explanation of the purpose and scope of Ohio's TCPs; college tech prep program standards; an overview…

  20. Ohio Marketing Management and Research. Technical Competency Profile (TCP).

    Science.gov (United States)

    Ray, Gayl M.; Wilson, Nick; Mangini, Rick

    This document provides a framework for a broad-based secondary and postsecondary curriculum to prepare students for employment in marketing management and research (MMR). The first part of the technical competency profile (TCP) contains the following items: an explanation of the purpose and scope of Ohio's TCPs; college tech prep program…

  1. Mitigating TCP Degradation over Intermittent Link Failures using Intermediate Buffers

    Science.gov (United States)

    2006-06-01

    buffering strategy, retransmission strategy, TCP state management, intermediate ac- knowledgment, custody considerations, and leader election considerations...availability are all ripe for research in strategic buffering. One final custodial area open for pursuit is a leader election protocol. Along a route with

  2. Road traffic and cardiovascular health effects - Road traffic noise and air pollution

    NARCIS (Netherlands)

    Kluizenaar, Y. de; Miedema, H.M.E.

    2009-01-01

    Exposure to both environmental noise and air pollution has been associated with cardiovascular health effects. Until now, few studies have considered both stressors simultaneously. Two large studies were carried out investigating the relationship between road traffic noise and several cardiovascular

  3. 未来高带宽网络中FAST TCP与TCP Vegas的公平性分析%Fairness analysis of FAST TCP and TCP Vegas over future high-bandwidth internet

    Institute of Scientific and Technical Information of China (English)

    朱小松

    2012-01-01

    FAST TCP, a modern end-to-end protocol adopting queuing delay as a congestion measure. However, the lack of a precise measurement of queuing delay leads to a potential unfairness problem that FAST TCP flows may be discriminated against according to their starting times in a persistent congestion scenario, TCP Vegas also encounters the unfairness problem. The unfairness problem is quantitatively assessed by mathematical analysis and ns2 simulations, then, we compared FAST TCP with TCP Vegas. Consequently, FAST TCP demonstrates a competitive edge over TCP Vegas, under future high bandwidth-delay product environment. This conclusion will contribute to the improvement of FAST TCP for future reference.%FAST TCP是先进的端到端拥塞控制协议,采用队列时延作为拥塞度量.由于不能准确测得精确的队列时延,此协议中存有不公平的隐患,即在某些持续拥塞场景下,不同时刻启动的FAST TCP流会受到差别对待,TCP Vegas中同样存在不公平问题.通过数学分析和ns2仿真对这种不公平问题进行量化,进而比较FASTTCP与TCP Vegas在公平性问题上的性能差异.结果证明了在将来高带宽时延乘积网络环境下,FAST TCP在公平性上要明显优于TCP Vegas.这为对FAST TCP协议的改进给出了有价值的参照.

  4. A New Analytical Model for TCP Reno with Bursts Error Considered

    Institute of Scientific and Technical Information of China (English)

    DENG Jian-min; JI Hong; YUE Guang-xin; YIN Chang-chuan

    2003-01-01

    In this paper, we present a new analytical model for TCP Reno, and this method can also be used in other versions of TCP. The first order two-state Markovian model is used to describe the wireless link, so as to deal with the burst error in wireless links very well. The tineout mechanism of TCP is also considered and a geometric method describes the erponential growth of TCP timeout . Also this method is effective for the study of the growth of TCP transmission window. Analytical results indicate that this model is effective.

  5. Evolution and Expression Patterns of TCP Genes in Asparagales.

    Science.gov (United States)

    Madrigal, Yesenia; Alzate, Juan F; Pabón-Mora, Natalia

    2017-01-01

    CYCLOIDEA-like genes are involved in the symmetry gene network, limiting cell proliferation in the dorsal regions of bilateral flowers in core eudicots. CYC-like and closely related TCP genes (acronym for TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATION CELL FACTOR) have been poorly studied in Asparagales, the largest order of monocots that includes both bilateral flowers in Orchidaceae (ca. 25.000 spp) and radially symmetrical flowers in Hypoxidaceae (ca. 200 spp). With the aim of assessing TCP gene evolution in the Asparagales, we isolated TCP-like genes from publicly available databases and our own transcriptomes of Cattleya trianae (Orchidaceae) and Hypoxis decumbens (Hypoxidaceae). Our matrix contains 452 sequences representing the three major clades of TCP genes. Besides the previously identified CYC specific core eudicot duplications, our ML phylogenetic analyses recovered an early CIN-like duplication predating all angiosperms, two CIN-like Asparagales-specific duplications and a duplication prior to the diversification of Orchidoideae and Epidendroideae. In addition, we provide evidence of at least three duplications of PCF-like genes in Asparagales. While CIN-like and PCF-like genes have multiplied in Asparagales, likely enhancing the genetic network for cell proliferation, CYC-like genes remain as single, shorter copies with low expression. Homogeneous expression of CYC-like genes in the labellum as well as the lateral petals suggests little contribution to the bilateral perianth in C. trianae. CIN-like and PCF-like gene expression suggests conserved roles in cell proliferation in leaves, sepals and petals, carpels, ovules and fruits in Asparagales by comparison with previously reported functions in core eudicots and monocots. This is the first large scale analysis of TCP-like genes in Asparagales that will serve as a platform for in-depth functional studies in emerging model monocots.

  6. Evolution and Expression Patterns of TCP Genes in Asparagales

    Science.gov (United States)

    Madrigal, Yesenia; Alzate, Juan F.; Pabón-Mora, Natalia

    2017-01-01

    CYCLOIDEA-like genes are involved in the symmetry gene network, limiting cell proliferation in the dorsal regions of bilateral flowers in core eudicots. CYC-like and closely related TCP genes (acronym for TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATION CELL FACTOR) have been poorly studied in Asparagales, the largest order of monocots that includes both bilateral flowers in Orchidaceae (ca. 25.000 spp) and radially symmetrical flowers in Hypoxidaceae (ca. 200 spp). With the aim of assessing TCP gene evolution in the Asparagales, we isolated TCP-like genes from publicly available databases and our own transcriptomes of Cattleya trianae (Orchidaceae) and Hypoxis decumbens (Hypoxidaceae). Our matrix contains 452 sequences representing the three major clades of TCP genes. Besides the previously identified CYC specific core eudicot duplications, our ML phylogenetic analyses recovered an early CIN-like duplication predating all angiosperms, two CIN-like Asparagales-specific duplications and a duplication prior to the diversification of Orchidoideae and Epidendroideae. In addition, we provide evidence of at least three duplications of PCF-like genes in Asparagales. While CIN-like and PCF-like genes have multiplied in Asparagales, likely enhancing the genetic network for cell proliferation, CYC-like genes remain as single, shorter copies with low expression. Homogeneous expression of CYC-like genes in the labellum as well as the lateral petals suggests little contribution to the bilateral perianth in C. trianae. CIN-like and PCF-like gene expression suggests conserved roles in cell proliferation in leaves, sepals and petals, carpels, ovules and fruits in Asparagales by comparison with previously reported functions in core eudicots and monocots. This is the first large scale analysis of TCP-like genes in Asparagales that will serve as a platform for in-depth functional studies in emerging model monocots. PMID:28144250

  7. 使用Sniffer软件透视TCP/IP协议的安全%To Analyze the Security of TCP/IP Protocol Using Sniffer Software

    Institute of Scientific and Technical Information of China (English)

    张保江

    2014-01-01

    TCP/IP协议是当前计算机局域网和Internet普遍使用的组网协议,该文结合TCP/IP的一个通信实例,使用Sniffer软件,截取并分析其通信数据,得出TCP/IP协议缺乏相应的安全机制的结论,并在此基础上,讨论了基于TCP/IP协议的有关安全的常用做法。%TCP/IP is the protocol that commonly used to build the Ethernet or Internet. Based on an instance of TCP/IP com-munication, the thesis uses the sniffer software to capture and analyze the data of TCP/IP communications and draws the conclu-sion that TCP/IP protocol has no measures to ensure the security of the communications. At last the thesis introduces some ways to ensure the security of TCP/IP communications.

  8. VB客户——服务器(TCP/IP)编程%Using VB Design Client-Server(TCP/IP) Network Program

    Institute of Scientific and Technical Information of China (English)

    陶运道

    2002-01-01

    利用VB的 WinSock 控件可以与远程计算机建立连接,并通过用户数据文报协议(UDP)或者传输控制协议(TCP)进行数据交换.TCP/IP协议是Internet最重要的协议.VB提供了WinSock控件,用于在TCP/IP的基础上进行网络通信.本文介绍如何用VB来实现TCP/IP网络编程.

  9. Investigation of TCP Veno Performance over Wirless Ad Hoc Network%TCP Veno在无线Ad Hoc网络中的性能分析

    Institute of Scientific and Technical Information of China (English)

    唐述; 谢显中; 赵锐

    2007-01-01

    分析了TCP Veno在无线Ad Hoc这样的多跳的网络中的性能,并分SANET(静态无线多跳网络)和MANET(移动无线多跳网络)两种网络环境进行仿真分析,结果显示TCP Veno的性能较TCP Reno有一定程度的改进,但并没有在无线单跳网络中的性能优势出色,这对实际应用TCP Veno很重要.

  10. 尼罗罗非鱼TCP-1-beta和TCP-1-eta的分子特征及其低温诱导表达%MOLECULAR CHARACTERIZATION AND INDUCTION EXPRESSION OF TCP-1-BETA AND TCP-1-ETA UNDER LOW TEMPERATURES IN TILAPIA OREOCHROMIS NILOTICUS

    Institute of Scientific and Technical Information of China (English)

    谢建丽; 林勇; 曾兰; 王忠卫; 桂建芳

    2012-01-01

    为了研究尼罗罗非鱼耐寒性状的分子基础并为耐寒品种选育提供参考,研究从尼罗罗非鱼中克隆了HSP60家族TCP-1-beta和TCP-1-eta基因并对其在低温诱导下的表达特征进行了分析.尼罗罗非鱼TCP-1-beta cDNA长度为1755 bp,包括1605 bp的完整开放阅读框,编码534个氨基酸;尼罗罗非鱼TCP-1-eta cDNA长度1651 bp,包括1638 bp的完整开放阅读框,编码545个氨基酸.与其他物种同源基因的蛋白序列比对结果显示,TCP-1-beta和TCP-1-eta蛋白在物种间同源性很高,且都具有保守的ATP结合结构域等,预示其在物种间功能的保守性.实时荧光定量PCR结果表明:TCP-1-beta和TCP-1-eta在各组织中呈遍在表达,但在肌肉中表达量最高;诱导温度从22℃降至12℃,不同低温诱导48h后TCP-1-beta和TCP-1-eta均呈上调表达,在18℃时表达开始上调,随着低温胁迫程度加强,表达上调幅度增大,至12℃时表达量达到最高,TCP-1-beta和TCP-1-eta上调幅度分别达到常温的12.2倍和10.7倍.这些结果预示在尼罗罗非鱼中,TCP-1-beta和TCP-1-eta是潜在的耐寒相关基因.%Nile tilapia (Oreochromis niloticus) is one of the commercially important fish species in the southern China, but the lack of cold-resistant strains in tilapia results in a large number of deaths in winter and early spring. Some heat-shock proteins (Hsps) have been revealed to facilitate correct folding of other proteins under diverse forms of physiological stresses, such as extreme temperatures, chemical toxicity and oxidative stress. To understand the molecular mechanism of cold tolerance in fish, we cloned the full-length cDNAs of TCP-1-beta and TCP-1-eta of the Hsp60 family in nile tilapia {Oreochromis niloticus), and studied their expression patterns under normal and low temperature treatments. The TCP-1-beta cDNA consisted of 1755 bp and encoded a peptide of 534 amino acids. The TCP-1-eta cDNA consisted of 1651 bp and encoded a peptide of 545

  11. Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles.

    Science.gov (United States)

    Zhang, Yulong; Dong, Rui; Park, Yujin; Bohner, Marc; Zhang, Xinli; Ting, Kang; Soo, Chia; Wu, Benjamin M

    2016-09-10

    NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein's bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research.

  12. Improvement of β-TCP/PLLA biodegradable material by surface modification with stearic acid.

    Science.gov (United States)

    Ma, Fengcang; Chen, Sai; Liu, Ping; Geng, Fang; Li, Wei; Liu, Xinkuan; He, Daihua; Pan, Deng

    2016-05-01

    Poly-L-lactide (PLLA) is a biodegradable polymer and used widely. Incorporation of beta tricalcium phosphate (β-TCP) into PLLA can enhance its osteoinductive properties. But the interfacial layer between β-TCP particles with PLLA matrix is easy to be destroyed due to inferior interfacial compatibility of the organic/inorganic material. In this work, a method of β-TCP surface modification with stearic acid was investigated to improve the β-TCP/PLLA biomaterial. The effects of surface modification on the β-TCP were investigated by FTIR, XPS, TGA and CA. It was found that the stearic acid reacted with β-TCP and oxhydryl was formed during the surface modification. Hydrophilicity of untreated or modified β-TCP/PLLA composite was increased by the addition of 10 wt.% β-TCP, but it decreased as the addition amount increased from 10 wt.% to 20 wt.%. Two models were suggested to describe the effect of β-TCP concentration on CA of the composites. Mechanical properties of β-TCP/PLLA composites were tested by bending and tensile tests. Fractures of the composites after mechanical test were observed by SEM. It was found that surface modification with stearic acid improved bending and tensile strengths of the β-TCP/PLLA composites obviously. The SEM results indicated that surface modification decreased the probability of interface debonding between fillers and matrix under load.

  13. 10~Gbps TCP/IP streams from the FPGA for High Energy Physics

    CERN Document Server

    Bauer, Gerry; Branson, James; Chaze, Olivier; Cittolin, Sergio; Coarasa Perez, Jose Antonio; Darlea, Georgiana Lavinia; Deldicque, Christian; Dobson, Marc; Dupont, Aymeric; Erhan, Samim; Gigi, Dominique; Glege, Frank; Gomez Ceballos, Guillelmo; Gomez-Reino Garrido, Robert; Hartl, Christian; Hegeman, Jeroen Guido; Holzner, Andre Georg; Masetti, Lorenzo; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; Nunez Barranco Fernandez, Carlos; O'Dell, Vivian; Orsini, Luciano; Ozga, Wojciech Andrzej; Paus, Christoph Maria Ernst; Petrucci, Andrea; Pieri, Marco; Racz, Attila; Raginel, Olivier; Sakulin, Hannes; Sani, Matteo; Schwick, Christoph; Spataru, Andrei Cristian; Stieger, Benjamin Bastian; Sumorok, Konstanty; Veverka, Jan; Wakefield, Christopher Colin; Zejdl, Petr

    2014-01-01

    The DAQ system of the CMS experiment at CERN collects data from more than 600 custom detector Front-End Drivers (FEDs). During 2013 and 2014 the CMS DAQ system will undergo a major upgrade to address the obsolescence of current hardware and the requirements posed by the upgrade of the LHC accelerator and various detector components. For a loss-less data collection from the FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. To limit the TCP hardware implementation complexity the DAQ group developed a simplified and unidirectional but RFC~793 compliant version of the TCP protocol. This allows to use a PC with the standard Linux TCP/IP stack as a receiver. We present the challenges and protocol modifications made to TCP in order to simplify its FPGA implementation. We also describe the interaction between the simplified TCP and Linux TCP/IP stack including the performance measurements.

  14. TCP Veno在无线AdHoc网络中的性能比较研究

    Institute of Scientific and Technical Information of China (English)

    唐述; 谢显中; 赵锐

    2007-01-01

    TCP Veno是一种新的无线网络环境下TCP的拥塞控制机制,它综合了TCP Reno和TCP Vegas的特点,对单跳无线网络的性能有了较大的改善。对TCP Veno应用于无线多跳网络中的性能进行研究,将TCP Veno在三种不同的无线AdHoc路由协议下的性能进行了仿真分析和比较,结果显示TCP Veno在不同的路由协议下的性能有所不同,通过比较,可以找到一个在无线AdHoc网络中更适合TCP Veno的路由协议。

  15. TCP transcription factors are critical for the coordinated regulation of isochorismate synthase 1 expression in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Xiaoyan; Gao, Jiong; Zhu, Zheng; Dong, Xianxin; Wang, Xiaolei; Ren, Guodong; Zhou, Xin; Kuai, Benke

    2015-04-01

    Salicylic acid (SA) plays an important role in various aspects of plant development and responses to stresses. To elucidate the sophisticated regulatory mechanism of SA synthesis and signaling, we used a yeast one-hybrid system to screen for regulators of isochorismate synthase 1 (ICS1), a gene encoding the key enzyme in SA biosynthesis in Arabidopsis thaliana. A TCP family transcription factor AtTCP8 was initially identified as a candidate regulator of ICS1. The regulation of ICS1 by TCP proteins is supported by the presence of a typical TCP binding site in the ICS1 promoter. The binding of TCP8 to this site was confirmed by in vitro and in vivo assays. Expression patterns of TCP8 and its corresponding gene TCP9 largely overlapped with ICS1 under pathogen attack. A significant reduction in the expression of ICS1 during immune responses was observed in the tcp8 tcp9 double mutant. We also detected strong interactions between TCP8 and SAR deficient 1 (SARD1), WRKY family transcription factor 28 (WRKY28), NAC (NAM/ATAF1,ATAF2/CUC2) family transcription factor 019 (NAC019), as well as among TCP8, TCP9 and TCP20, suggesting a complex coordinated regulatory mechanism underlying ICS1 expression. Our results collectively demonstrate that TCP proteins are involved in the orchestrated regulation of ICS1 expression, with TCP8 and TCP9 being verified as major representatives.

  16. Injuries to pedestrians in road traffic accidents.

    OpenAIRE

    Atkins, R. M.; Turner, W H; Duthie, R. B.; Wilde, B. R.

    1988-01-01

    Although there have been many reports on injuries to occupants of cars in road traffic accidents, there have been few prospective studies of injuries to pedestrians in such accidents. For this reason a two year prospective study of pedestrians in road traffic accidents in the Oxford region was carried out. The incidence of death in pedestrians was significantly higher than in car occupants or motorcyclists. The principal determinant of death was the weight of the vehicle concerned. The most c...

  17. Subjective safety in traffic.

    NARCIS (Netherlands)

    2012-01-01

    The term ‘subjective safety in traffic’ refers to people feeling unsafe in traffic or, more generally, to anxiety regarding being unsafe in traffic for oneself and/or others. Subjective safety in traffic can lead to road users limiting their mobility and social activities, which is one of the reason

  18. Performance Evaluation of AODV and DSR with Varying Pause Time and Speed Time Over TCP and CBR Connections in VANET

    Directory of Open Access Journals (Sweden)

    Bijan Paul

    2012-01-01

    Full Text Available VANET (Vehicular Ad-hoc Network is a new technology which has taken enormous attention in the recent years. Vehicular ad hoc network is formed by cars which are called nodes; allow them to communicate with one another without using any fixed road side unit. It has some unique characteristics which make it different from other ad-hoc network as well as difficult to define any exact mobility model and routing protocols because of their high mobility and changing mobility pattern. Hence performance of routing protocols can vary with the various parameters such as speed, pause time, node density and traffic scenarios. In this research paper, the performance of two on-demand routing protocols AODV and DSR has been analyzed by means of packet delivery ratio, loss packet ratio average end-to-end delay with varying pause time, speed time and node density under TCP and CBR connection.

  19. Performance Evaluation of Aodv&DSR with Varying Pause Time & Node Density Over TCP&CBR Connections in Vanet

    CERN Document Server

    Paul, Bijan; Bikas, Md Abu Naser

    2012-01-01

    Vehicular ad hoc network is formed by cars which are called nodes; allow them to communicate with one another without using any fixed road side unit. It has some unique characteristics which make it different from other ad hoc network as well as difficult to define any exact mobility model and routing protocols because of their high mobility and changing mobility pattern. Hence performance of routing protocols can vary with the various parameters such as speed, pause time, node density and traffic scenarios. In this research paper, the performance of two on-demand routing protocols AODV & DSR has been analyzed by means of packet delivery ratio, loss packet ratio & average end-to-end delay with varying pause time and node density under TCP & CBR connection.

  20. Performance Evaluation of AODV & DSR with Varying Pause Time & Speed Time Over TCP & CBR Connections in VANET

    CERN Document Server

    Paul, Bijan; Bikas, Md Abu Naser

    2012-01-01

    VANET (Vehicular Ad-hoc Network) is a new technology which has taken enormous attention in the recent years. Vehicular ad hoc network is formed by cars which are called nodes; allow them to communicate with one another without using any fixed road side unit. It has some unique characteristics which make it different from other ad hoc network as well as difficult to define any exact mobility model and routing protocols because of their high mobility and changing mobility pattern. Hence performance of routing protocols can vary with the various parameters such as speed, pause time, node density and traffic scenarios. In this research paper, the performance of two on-demand routing protocols AODV & DSR has been analyzed by means of packet delivery ratio, loss packet ratio & average end-to-end delay with varying pause time, speed time and node density under TCP & CBR connection.

  1. OPTIMIZATION OF URBAN MULTI-INTERSECTION TRAFFIC FLOW VIA Q-LEARNING

    Directory of Open Access Journals (Sweden)

    Yit Kwong Chin

    2013-01-01

    Full Text Available Congestions of the traffic flow within the urban traffic network have been a challenging task for all the urban developers. Many approaches have been introduced into the current system to solve the traffic congestion problems. Reconfiguration of the traffic signal timing plan has been carried out through implementation of different techniques. However, dynamic characteristics of the traffic flow increase the difficulties towards the ultimate solutions. Thus, traffic congestions still remain as unsolvable problems to the current traffic control system. In this study, artificial intelligence method has been introduced in the traffic light system to alter the traffic signal timing plan to optimize the traffic flows. Q-learning algorithm in this study has enhanced the traffic light system with learning ability. The learning mechanism of Q-learning enables traffic light intersections to release itself from traffic congestions situation. Adjacent traffic light intersections will work independently and yet cooperate with each others to a common goal of ensuring the fluency of the traffic flows within the traffic network. The simulated results show that the Q-Learning algorithm is able to learn from the dynamic traffic flow and optimize the traffic flow accordingly.

  2. Modeling of TCP-Rab throughput and its empirical study%TCP-Rab的吞吐量模型及实验研究

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    基于接收端通告的TCP(TCP-Rab,receiver advertisement based TCP)协议是我们实现的一种新的TCP协议,在文献[1]中对TCP-Rab的算法设计、实现进行了详细阐述.本文对TCP-Rab进行了少量改进,重点导出了TCP-Rab的吞吐量性能模型,并对TCP-Rab进行了试验研究.该模型采用统计的方法,在导出TCP-Rab的吞吐量性能模型的时候,不仅考虑了TCP连接的拥塞避免阶段对吞吐量的影响,也考虑了慢启动阶段对吞吐量的影响,同时还考虑了一个发送窗口内多个数据包随机丢失对吞吐量的影响,因此该模型能适用于实际的网络环境中.

  3. TCP Upload and Download Fairness over IEEE 802.11 Wired-cum-Wireless Heterogeneous Networks

    Institute of Scientific and Technical Information of China (English)

    REN Wei; JIN Hai

    2007-01-01

    A scheme of setting a limit to the TCP sending window size is proposed to improve the TCP fairness between upload and/or download flows in wired-cum-wireless networks. The goodput and delay of the upload and download TCP flows are compared to evaluate the TCP fairness for different schemes, which are the different combinations of setting a limit (64 or 4) to the sending window size and using the delayed acknowledgement (ACK) scheme or not. Extensive simulation results and analysis show that ( 1 )for TCP download flows, setting the limit of sending window size to 4 can improve the fairness; (2) for TCP upload flows, limiting the sending window size and using the delayed ACK strategy are both beneficial to fairness; (3) for TCP download and upload mixture flows, limiting the sending window size to a small value ( e. g. , 4) rather than using the delayed ACK strategy, is the solution to improvement of the fairness; (4) a large delay interval (200 ms or 300 ms) does not result in improvement in fairness and performance; (5) a larger TCP packet size ( 1 400 B) can improve the TCP upload goodput and decrease the download goodput; in contrast, a smaller TCP packet size (560 B) can increase the download goodput and decrease the upload goodput.

  4. A novel implementation of TCP Vegas for optical burst switched networks

    KAUST Repository

    Shihada, Basem

    2010-07-01

    TCP performance over bufferless Optical Burst Switched (OBS) networks could be significantly degraded due to the misinterpretation of network congestion status (referred to as false congestion detection). It has been reported that burst retransmission in the OBS domain can improve the TCP throughput by hiding burst loss events from the upper TCP layer, which can effectively reduce the congestion window fluctuation at the expense of introducing additional delay. However, the additional delay may cause performance degradation for delay-based TCP implementations that are sensitive to packet round trip time in estimating the network congestion status. In this paper, a novel implementation of TCP Vegas that adopts a threshold-based mechanism is proposed for identifying the network congestion status in OBS networks. Analytical models are developed to evaluate the throughput of conventional TCP Vegas and threshold-based Vegas over OBS networks with burst retransmission. Simulation is conducted to validate the analytical model and to compare threshold-based Vegas with a number of legacy TCP implementations, such as TCP Sack and TCP Reno. The analytical model can be used to obtain a proper threshold value that results in an optimal steady state TCP throughput.

  5. BIFURCATIONS AND CHAOS CONTROL IN TCP-RED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Liu Fang

    2006-01-01

    Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.

  6. Design of feedback controller for TCP/AQM networks

    Directory of Open Access Journals (Sweden)

    Sukant Kishoro Bisoy

    2017-02-01

    Full Text Available In this paper, we propose a novel proportional-differential-type feedback controller called Novel-PD as new active queue management (AQM to regulate the queue length with small oscillation. It measures the current queue length and uses the current queue length and differential error signals to adjust packet drop probability dynamically. We provide control theoretic analysis of system stability and develop guidelines to select control gain parameters of Novel-PD. The design of Novel-PD for TCP/AQM system is given in details. NS2 is used for conducting extensive simulation. The proposed controller is compared with random early detection (RED, random exponential marking (REM, proportional integrator (PI and proportional derivative (PD controller. Result shows that, Novel-PD is stable and achieves faster response in dynamic environments where number of TCP connections, bottleneck capacity, round trip time (RTT keeps changing. The proposed controller outperforms other AQM schemes.

  7. TCP15 modulates cytokinin and auxin responses during gynoecium development in Arabidopsis.

    Science.gov (United States)

    Lucero, Leandro E; Uberti-Manassero, Nora G; Arce, Agustín L; Colombatti, Francisco; Alemano, Sergio G; Gonzalez, Daniel H

    2015-10-01

    We studied the role of Arabidopsis thaliana TCP15, a member of the TEOSINTE BRANCHED1-CYCLOIDEA-PCF (TCP) transcription factor family, in gynoecium development. Plants that express TCP15 from the 35S CaMV promoter (35S:TCP15) develop flowers with defects in carpel fusion and a reduced number of stigmatic papillae. In contrast, the expression of TCP15 fused to a repressor domain from its own promoter causes the development of outgrowths topped with stigmatic papillae from the replum. 35S:TCP15 plants show lower levels of the auxin indoleacetic acid and reduced expression of the auxin reporter DR5 and the auxin biosynthesis genes YUCCA1 and YUCCA4, suggesting that TCP15 is a repressor of auxin biosynthesis. Treatment of plants with cytokinin enhances the developmental effects of expressing TCP15 or its repressor form. In addition, treatment of a knock-out double mutant in TCP15 and the related gene TCP14 with cytokinin causes replum enlargement, increased development of outgrowths, and the induction of the auxin biosynthesis genes YUCCA1 and YUCCA4. A comparison of the phenotypes observed after cytokinin treatment of plants with altered expression levels of TCP15 and auxin biosynthesis genes suggests that TCP15 modulates gynoecium development by influencing auxin homeostasis. We propose that the correct development of the different tissues of the gynoecium requires a balance between auxin levels and cytokinin responses, and that TCP15 participates in a feedback loop that helps to adjust this balance.

  8. Analysis of Sister Carrie

    Institute of Scientific and Technical Information of China (English)

    孙淑珍

    2004-01-01

    Chapter Ⅰ Introduction  Sitting in the rocking chair,Carrie dreams her future.This is the deep impression the novel"Sister Carrie"gives us,which is written by Theodore Dreiser(1871-1945),the great American realism writer.  ……

  9. A New Method for Fabrication of Nanohydroxyapatite and TCP from the Sea Snail Cerithium vulgatum

    Directory of Open Access Journals (Sweden)

    O. Gunduz

    2014-01-01

    Full Text Available Biphasic bioceramic nanopowders of hydroxyapatite (HA and β-tricalcium phosphate (TCP were prepared from shells of the sea snail Cerithium vulgatum (Bruguière, 1792 using a novel chemical method. Calcination of the powders produced was carried out at varying temperatures, specifically at 400°C and 800°C, in air for 4 hours. When compared to the conventional hydrothermal transformation method, this chemical method is very simple, economic, due to the fact that it needs inexpensive and safe equipment, because the transformation of the aragonite and calcite of the shells into the calcium phosphate phases takes place at 80°C under the atmospheric pressure. The powders produced were determined using infrared spectroscopy (FT-IR, X-ray diffraction, and scanning electron microscopy (SEM. The features of the powders produced along with the fact of their biological origin qualify these powders for further consideration and experimentation to fabricate nanoceramic biomaterials.

  10. TCP/IP Sockets in C# Practical Guide for Programmers

    CERN Document Server

    Makofske, David; Calvert, Kenneth L

    2004-01-01

    "TCP/IP sockets in C# is an excellent book for anyone interested in writing network applications using Microsoft .Net frameworks. It is a unique combination of well written concise text and rich carefully selected set of working examples. For the beginner of network programming, it''s a good starting book; on the other hand professionals could also take advantage of excellent handy sample code snippets and material on topics like message parsing and asynchronous programming."Adarsh Khare, SDT, .Net Frameworks Team, Microsoft CorporationThe popularity of the C# language and the .NET framework is ever rising due to its ease of use, the extensive class libraries available in the .NET Framework, and the ubiquity of the Microsoft Windows operating system, to name a few advantages. TCP/IP Sockets in C# focuses on the Sockets API, the de facto standard for writing network applications in any programming language. Starting with simple client and server programs that use TCP/IP (the Internet protocol suite), students ...

  11. TCP Issues in Mobile Ad Hoc Networks: Challenges and Solutions

    Institute of Scientific and Technical Information of China (English)

    Wei-Qiang Xu; Tie-Jun Wu

    2006-01-01

    Mobile ad hoc networks (MANETs) are a kind of very complex distributed communication systems with wireless mobile nodes that can be freely and dynamically self-organized into arbitrary and temporary network topologies. MANETs inherit several limitations of wireless networks, meanwhile make new challenges arising from the specificity of MANETs, such as route failures, hidden terminals and exposed terminals. When TCP is applied in a MANET environment, a number of tough problems have to be dealt with. In this paper, a comprehensive survey on this dynamic field is given. Specifically, for the first time all factors impairing TCP performance are identified based on network protocol hierarchy, I.e., lossy wireless channel at the physical layer; excessive contention and unfair access at the MAC layer; frail routing protocol at the network layer, the MAC layer and the network layer related mobile node; unfit congestion window size at the transport layer and the transport layer related asymmetric path. How these factors degrade TCP performance is clearly explained. Then, based on how to alleviate the impact of each of these factors listed above, the existing solutions are collected as comprehensively as possible and classified into a number of categories, and their advantages and limitations are discussed. Based on the limitations of these solutions, a set of open problems for designing more robust solutions is suggested.

  12. A Marine Traffic Flow Model

    Directory of Open Access Journals (Sweden)

    Tsz Leung Yip

    2013-03-01

    Full Text Available A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on one ship or two ships but does not address the issues in marine traffic flow.

  13. Implications of traffic characteristics on interdomain traffic engineering

    OpenAIRE

    Uhlig, Steve

    2004-01-01

    This thesis discusses the implications of the traffic characteristics on interdomain traffic engineering with BGP. We first provide an overview of the interdomain traffic control problem. Then, we present results concerning the characteristics of the interdomain traffic, based on the analysis of real traffic traces gathered from non-transit ASes. We discuss the implications of the topological properties of the traffic on interdomain traffic engineering. Based on this knowledge of the...

  14. Structural and chemical analysis of silica-doped β-TCP ceramic coatings on surgical grade 316L SS for possible biomedical application

    Directory of Open Access Journals (Sweden)

    Karuppasamy Prem Ananth

    2015-09-01

    Full Text Available We have developed a novel approach to introduce silica-doped β-tricalcium phosphate (Si-β-TCP on 316L SS substrates for enhanced biological properties. Doping of β-TCP with silica loadings ranging from 0 to 8 mol% was carried out using chemical precipitation method. Si-β-TCP powder was sintered at 800 °C followed by coating it on 316L SS substrate using electrophoretic deposition. The coated and uncoated samples were investigated by various characterization techniques such as X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, field emission scanning electron microscopy (FESEM and X-ray fluorescence spectroscopy (XRF. Biomineralization ability of the coatings was evaluated by immersing in simulated body fluid (SBF solution for different number of days such as 7, 14, 21 and 28 days. The results obtained in our study have shown that the apatite formation ability was high for the 8 mol% of Si-β-TCP. This will promote better biomineralization ability compared to the other coatings.

  15. Analysis and application of C++layer protocol TCP/IP%TCP/IP应用层协议分析与C++实现

    Institute of Scientific and Technical Information of China (English)

    杜晓春; 刘婉妮; 王宏

    2013-01-01

    With the rapid development of the Internet today,as Internet based TCP/IP protocol has penetrated into every aspect of our lives.This paper makes a detailed analysis on the application layer protocol in TCP/IP protocol;then introduces how to use the C++ programming language,the TCP/IP protocol Telnet,FTP application layer protocol in a visual,easy operation of the client/server mode (C/S mode) show.In order to facilitate the people to better understand the TCP/IP protocol,the work principle of TCP/IP protocol and the reference value for network application development.%在互联网高速发展的今天,作为Internet国际互联网络基础的TCP/IP协议已经渗透到我们生活的各个方面。本文首先对TCP/IP协议中的应用层协议进行了详细的分析;然后介绍了如何运用C++语言进行编程,将TCP/IP协议中的Telnet、FTP等应用层协议以一种可视化、易操作的客户端/服务器端模式(C/S模式)展现出来。从而便于人们更好的认识和理解TCP/IP协议,对了解TCP/IP协议的工作原理及进行网络应用程序开发一定的参考价值。

  16. Cellphone as a Traffic Guidance System

    Directory of Open Access Journals (Sweden)

    Abdallah Alashqur

    2012-07-01

    Full Text Available The worldwide proliferation of cellphones has created numerous opportunities for new and powerful applications that contribute towards improving the quality of life. Traffic problems due to traffic congestions, especially in cities with high population density, is one of the areas that need attention. GPS-enabled cellphones can contribute towards alleviating some of these traffic problems. A GPS-enabled cellphone can be a source of useful information pertaining to traffic congestions. The velocity and location information that are transmitted by GPSs on the road can be gathered and analyzed at run-time to determine traffic status. In addition, a cellphone can receive area maps with overplayed traffic information to help drivers select optimal routes for their trips. In this paper we describe a prototype system that enables passengers who are carrying cellphones to know, in advance, the best route that a taxi needs to take by providing them with distance information, taxi fare estimate, and traffic congestion status. The system can be of benefit to other types of users in addition to passengers wanting to ride a taxi.

  17. TCP-RC增强Ad hoc网络TCP性能%Enhance TCP Performance in Ad hoc Network by TCP-RC

    Institute of Scientific and Technical Information of China (English)

    周建新; 石冰心

    2006-01-01

    目前改善Ad hoc网络中TCP性能的方法通常在路由中断/变化时暂时性地冷冻TCP连接,在路由重建后从冷冻的状态继续TCP传输.但TCP源端和目的端之间的路由在中断前和重建后可能完全不同,所以路由重建后TCP仍从路由中断前的状态继续TCP传输并不一定合适.本文提出了TCP-RC,它在路由重建后重新计算cwnd和ssthresh,使得TCP恢复传输时能根据当前TCP连接上的容量自适应地调整发送速率,降低突发流量造成网络拥塞的可能性.仿真表明TCP-RC在Ad hoc网络中取得了更好TCP性能.

  18. FAST TCP over optical burst switched networks: Modeling and stability analysis

    KAUST Repository

    Shihada, Basem

    2013-04-01

    FAST TCP is important for promoting data-intensive applications since it can cleverly react to both packet loss and delay for detecting network congestion. This paper provides a continuous time model and extensive stability analysis of FAST TCP congestion-control mechanism in bufferless Optical Burst Switched Networks (OBS). The paper first shows that random burst contentions are essential to stabilize the network, but cause throughput degradation in FAST TCP flows when a burst with all the packets from a single round is dropped. Second, it shows that FAST TCP is vulnerable to burst delay and fails to detect network congestion due to the little variation of round-trip time, thus unstable. Finally it shows that introducing extra delays by implementing burst retransmission stabilizes FAST TCP over OBS. The paper proves that FAST TCP is not stable over barebone OBS. However, it is locally, exponentially, and asymptotically stable over OBS with burst retransmission.

  19. A new Grid Product of Tropical Cyclone Precipitation (TCP) for North America from 1930 to 2013

    Science.gov (United States)

    Zhu, L.

    2015-12-01

    We first developed a new method that collects daily TCP by using historical storm tracks and precipitation observation based on daily rain gauges in both U.S. and Mexico and calibrated it with satellite precipitation observation. We used a parametrized wind field to correct the possible under-estimations of precipitation in rain gauges. Grid interpolation parameters were optimized by testing different historical rain gauge densities and comparing our grid estimation of TCP and the observation from TRMM Multi-satellite Precipitation Analysis (3B42) by for the data available period from 1998 to 2013. The calibrated method was then used for the whole 94 years of TCP estimation. The preliminary result shows that the frequency of TCP events does not have significant change but the TCP intensity has significant increasing trends, especially in certain locations in North Carolina and Yucatan Peninsula in Mexico. This new long term TCP climatology can potentially assist model calibration and disaster prevention/mitigation.

  20. STUDY THE EFFECTIVENESS APPLICATIONS OF FUZZY CONTROLLER WITH TWO ENTRANCES IN THE SYSTEM OF ACTIVE QUEUE MANAGEMENT THE PACKETS IN TCP/IP NETWORKS

    Directory of Open Access Journals (Sweden)

    O. V. Nevdachyna

    2016-01-01

    Full Text Available The paper presents an approach to solving the overloading problem in TCP/IP networks. Offered fuzzy controller with two inputs for system of active queue management packages in TCP/IP networks, and investigated its use in these systems with a random change of traffic load. Proposed controller has two inputs, one of which is the value of the difference between the current queue length and the second – the difference between the current level of usage of the buffer. The output of the fuzzy controller calculates the probability of discarding packet.Mathematical model system of active queue management that is studied is presented in an interactive MATLAB system, in wherein also is demonstrated the processes occurring in the system with a random change of traffic load. The research results show that the AQM-system with fuzzy controller with two entrances stable enough maintains the desired current length the queue for sufficiently small values of the probability of dropping/marking packets (at acceptable size of queue q0= 200 packets, the average probability of dropping / marking is not more than 3,5×10–3 or less 0,35% packets is discarded or marked from the total number of incoming packets. The results obtained will help improve the efficiency of the functioning and operation of TCP / IP networks by increasing data transmission quality. this happens due introduction of the proposed controller at the design of new, more efficient routers for networks to minimize the delay of information.

  1. Some Aspects about a Self-Testing Solution for Implementing the TCP/IP Protocol

    Directory of Open Access Journals (Sweden)

    Daniela E.Popescu

    2008-05-01

    Full Text Available TCP is a connection-oriented, end-to-endreliable protocol designed to fit into a layeredhierarchy of protocols which support multi-networkapplications. The paper focuses on comparing theefficiencies of realizing a hardware implementationfor the TCP protocol.In order to estimate the advantages of such ahardware implementation we show in this paper thecomparative results of the classical implementationwith that of a self-testing implementation of TCP.

  2. 关于上Internet网和TCP/IP协议的实用技术

    Institute of Scientific and Technical Information of China (English)

    Tracy Thomas; 梁合庆

    2000-01-01

    @@ TCP/IP包括一系列协议 首先,应理解我们所说的TCP/IP是统指一系列的协议,其中包括TCP(传输控制协议)、UDP(用户数据报协议)、IP(Internet协议),还有一些更低层的连接层协议,如Ethernet(以太网协议)等.

  3. 基于TOE技术的硬线TCP/IP协议栈设计

    Institute of Scientific and Technical Information of China (English)

    徐俊; 黄静; 张泰然; 李刚

    2008-01-01

    本文介绍了当今互联网的发展和TOE技术,介绍了TCP/IP协议栈的原理,提出了TCP/IP协议栈芯片的设计。在设计中,实现了剪裁了的TCP/IP协议栈,主要实现了TCP协议、UDP协议、IP协议、ARP协议和ICMP协议。

  4. Performance Analysis of TCP Vegas-based LTE Network Congestion Control Algorithm%基于TCP Vegas的LTE网络拥塞控制算法性能分析

    Institute of Scientific and Technical Information of China (English)

    刘靖

    2015-01-01

    TCP Vegas和TCP Reno相比,虽然性能更强,吞吐量更高,但若将TCP Vegas部署在新的网络上仍存在较多障碍.以4G的LTE系统中部署TCP Vegas为例,分别对慢启动阶段的阈值设置和拥塞避免阶段的拥塞避免机制作相应改进.使用NS-2网络仿真LTE模型,结果表明TCP Vegas与TCP Reno相比具有更好的性能.

  5. Costs of traffic injuries

    DEFF Research Database (Denmark)

    Kruse, Marie

    2015-01-01

    assessed using Danish national healthcare registers. Productivity costs were computed using duration analysis (Cox regression models). In a subanalysis, cost per severe traffic injury was computed for the 12 995 individuals that experienced a severe injury. RESULTS: The socioeconomic cost of a traffic......OBJECTIVE: The aim of this study was to analyse the socioeconomic costs of traffic injuries in Denmark, notably the healthcare costs and the productivity costs related to traffic injuries, in a bottom-up, register-based perspective. METHOD: Traffic injury victims were identified using national...... emergency room data and police records. Victims were matched with five controls per case by means of propensity score, nearest-neighbour matching. In the cohort, consisting of the 52 526 individuals that experienced a traffic injury in 2000 and 262 630 matched controls, attributable healthcare costs were...

  6. TcpM: a novel relaxase that mediates transfer of large conjugative plasmids from Clostridium perfringens.

    Science.gov (United States)

    Wisniewski, Jessica A; Traore, Daouda A; Bannam, Trudi L; Lyras, Dena; Whisstock, James C; Rood, Julian I

    2016-03-01

    Conjugative transfer of toxin and antibiotic resistance plasmids in Clostridium perfringens is mediated by the tcp conjugation locus. Surprisingly, neither a relaxase gene nor an origin of transfer (oriT) has been identified on these plasmids, which are typified by the 47 kb tetracycline resistance plasmid pCW3. The tcpM gene (previously called intP) encodes a potential tyrosine recombinase that was postulated to be an atypical relaxase. Mutagenesis and complementation studies showed that TcpM was required for wild-type transfer of pCW3 and that a tyrosine residue, Y259, was essential for TcpM activity, which was consistent with the need for a relaxase-mediated hydrophilic attack at the oriT site. Other catalytic residues conserved in tyrosine recombinases were not required for TcpM activity, suggesting that TcpM was not a site-specific recombinase. Mobilization studies led to the identification of the oriT site, which was located in the 391 bp intergenic region upstream of tcpM. The oriT site was localized to a 150 bp region, and gel mobility shift studies showed that TcpM could bind to this region. Based on these studies we postulate that conjugative transfer of pCW3 involves the atypical relaxase TcpM binding to and processing the oriT site to initiate plasmid transfer.

  7. A Comparison of the TCP Variants Performance over different Routing Protocols on Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    S. R. Biradar

    2010-03-01

    Full Text Available We describe a variant of TCP (Tahoe, Vegas, TCP is most widely used transport protocol in both wired and wireless networks. In mobile ad hoc networks, the topology changes frequently due to mobile nodes, this leads to significant packet losses and network throughput degradation. This is due to the fact that TCP fails to distinguish the path failure and network congestion. In this paper, the performances of TCP over different routing (DSR, AODV and DSDV protocols in ad hoc networks wasstudied by simulation experiments and results are reported.

  8. Efficient enhancing scheme for TCP performance over satellite-based internet

    Institute of Scientific and Technical Information of China (English)

    Wang Lina; Gu Xuemai

    2007-01-01

    Satellite link characteristics drastically degrade transport control protocol (TCP) performance. An efficient performance enhancing scheme is proposed. The improvement of TCP performance over satellite-based Intemet is accomplished by protocol transition gateways at each end ora satellite link. The protocol which runs over a satellite link executes the receiver-driven flow control and acknowledgements- and timeouts-based error control strategies. The validity of this TCP performance enhancing scheme is verified by a series of simulation experiments. Results show that the proposed scheme can efficiently enhance the TCP performance over satellite-based Intemet and ensure that the available bandwidth resources of the satellite link are fully utilized.

  9. Preparation and Drug-release Behavior of β-TCP Ceramics Drug Carrier in vitro

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qihuan; YAN Xin; YAN Yuhua; DAI Honglian; JIANG Xin; LI Shipu

    2012-01-01

    β-TCP ceramics drug carrier was first prepared and characterized.SEM showed that β-TCP carrier was in porous amorphous structure with diameters around 10 μm.The physical properties including apparent porosity,volume-weight,tensile strength and the permeability were measured and the results indicated those properties fit the clinical usage of β-TCP drug carrier.Furthermore,drug release experiment in vitro showed that the carrier could prolong drug release in simulated body fluid which provides basis for the clinical use of β-TCP ceramics as drug carrier.

  10. Expression of caveolin-1 in the early phase of beta-TCP implanted in dog mandible.

    Science.gov (United States)

    Chou, Cherng-Tzeh; Bhawal, Ujjal K; Watanabe, Nobuyuki; Kuboyama, Noboru; Chang, Wei-Jen; Lee, Sheng-Yang; Abiko, Yoshimitsu

    2013-07-01

    Caveolin is an essential and signature protein of caveolae. Caveolin-1 participates in signal transduction processes by acting as a scaffolding protein that concentrates, organizes and functional regulates signalling molecules within caveolar membranes. Beta-tricalcium phosphate (β-TCP) has been widely used for scaffold in tissue engineering due to its high biodegradability, osteoconductivity, easy manipulation, and lack of histotoxicity. To better understand the role of caveolin-1 in bone homeostasis and response to β-TCP scaffold, β-TCP was implanted into the dog mandible defects in beagle dogs, and gene expression profiles were examined focused on the molecular components involved in caveolin-1 regulation. Here we showed the quantitative imageology analysis characterized using in vivo micro-computed tomography (CT) images at 4 and 7 days after β-TCP implanted in dog mandibles. The bone reformation by using the β-TCP scaffolds began within 4 days of surgery, and was healing well at 7 days after surgery. Higher mRNA level of caveolin-1 was observed in β-TCP-implanted Beagle dog mandibles compared with controls at day 4 and day 7 post-surgery. The enhancement of caveolin-1 by β-TCP was further confirmed by immunohistochemistry and immunofluorescence analysis. We further revealed increased Smad7 and Phospho Stat3 expression in β-TCP-implanted specimens. Taken together, these results suggest that the enhancement of caveolin-1 play an important role in accelerating bone formation by β-TCP.

  11. 2,4,6-trichlorophenol (TCP) photobiodegradation and its effect on community structure.

    Science.gov (United States)

    Zhang, Yongming; Pu, Xuejing; Fang, Miaomiao; Zhu, Jun; Chen, Lujun; Rittmann, Bruce E

    2012-07-01

    The mechanisms occurring in a photolytic circulating-bed biofilm reactor (PCBBR) treating 2,4,6-trichlorophenol (TCP) were investigated using batch experiments following three protocols: photodegradation alone (P), biodegradation alone (B), and intimately coupled photodegradation and biodegradation (P&B). Initially, the ceramic particles used as biofilm carriers rapidly adsorbed TCP, particularly in the B experiments. During the first 10 min, the TCP removal rate for P&B was equal to the sum of the rates for P and B, and P&B continued to have the greatest TCP removal, with the TCP concentration approaching zero only in the P&B experiments. When phenol, an easily biodegradable compound, was added along with TCP in order to promote TCP mineralization by means of secondary utilization, P&B was superior to P and B in terms of mineralization of TCP, giving 95% removal of chemical oxygen demand (COD). The microbial communities, examined by clone libraries, changed dramatically during the P&B experiments. Whereas Burkholderia xenovorans, a known degrader of chlorinated aromatics, was the dominant strain in the TCP-acclimated inoculum, it was replaced in the P&B biofilm by strains noted for biofilm formation and biodegrading non-chlorinated aromatics.

  12. Genome-wide identification and expression analysis of TCP transcription factors in Gossypium raimondii.

    Science.gov (United States)

    Ma, Jun; Wang, Qinglian; Sun, Runrun; Xie, Fuliang; Jones, Don C; Zhang, Baohong

    2014-10-16

    Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play versatile functions in multiple aspects of plant growth and development. However, no systematical study has been performed in cotton. In this study, we performed for the first time the genome-wide identification and expression analysis of the TCP transcription factor family in Gossypium raimondii. A total of 38 non-redundant cotton TCP encoding genes were identified. The TCP transcription factors were divided into eleven subgroups based on phylogenetic analysis. Most TCP genes within the same subfamily demonstrated similar exon and intron organization and the motif structures were highly conserved among the subfamilies. Additionally, the chromosomal distribution pattern revealed that TCP genes were unevenly distributed across 11 out of the 13 chromosomes; segmental duplication is a predominant duplication event for TCP genes and the major contributor to the expansion of TCP gene family in G. raimondii. Moreover, the expression profiles of TCP genes shed light on their functional divergence.

  13. Fabrication of Porous α-TCP/Gellan Gum Scaffold for Bone Tissue Engineering.

    Science.gov (United States)

    Wen, Jian; Kim, Ill Yong; Kikuta, Koichi; Ohtsuki, Chikara

    2016-03-01

    α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2) receives great attention for bone repairing due to its biodegradability and capability of transformation to human bone's main inorganic components, hydroxyapatite (HAp). α-TCP porous scaffold is easily procurable by sintering of the low-temperature polymorph of TCP, β-TCR Still, porous body of α-TCP is too brittle to being handled and shaped, limiting its clinical application as implant materials. To improve mechanical properties of α-TCP porous scaffold, the present study focused on coating of a type of polysaccharides on α-TCP scaffolds. Gellan gum was chosen as the polysaccharide for coating because of its biodegradability as well as the potential acting as substrate for HAp deposition during hydration of α-TCP after exposure to body fluid. After coating of gellan gum on α-TCP scaffolds with porosity of 75 vol%, the compressive strength increased from 0.45 MPa to around 2.00 MPa. Among the coated scaffold, the maximum compressive strength, 3.97 MPa, was obtained on the scaffold with porosity of 63 vol%. Improvement of mechanical properties of α-TCP/gellan gum composites was achieved to show easy handling performance for a bone substitute for tissue repairing. The dissolving rate of the coated scaffolds was also controlled by adjusting the concentration of GG solutions.

  14. Analysis of functional redundancies within the Arabidopsis TCP transcription factor family.

    Science.gov (United States)

    Danisman, Selahattin; van Dijk, Aalt D J; Bimbo, Andrea; van der Wal, Froukje; Hennig, Lars; de Folter, Stefan; Angenent, Gerco C; Immink, Richard G H

    2013-12-01

    Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein-protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein-protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family.

  15. Traffic Signs Inventory System

    Directory of Open Access Journals (Sweden)

    J. Ružbarský

    2013-06-01

    Full Text Available The paper is focused on practical application of Cambridge Correlator. The goal is to propose a traffic signs inventory system by using excellent characteristics of correlator in the rapid optical correlation. The proposal of this inventory system includes obtaining of traffic signs to create the database either collecting the GPS coordinates. It is necessary to know the traffic signs position and also to document the entire surface route for later evaluation in offline mode.

  16. TCP/IP协议中实现远程文件的传输%Remote File Transport by TCP/IP Protocol

    Institute of Scientific and Technical Information of China (English)

    任军

    2013-01-01

    TCP/IP是Internet的基本协议。远程文件传输是以TCP/IP协议为基础,采用Delphi控件,将TCP/IP通信函数封装在ActiveX控件中,通过对ActiveX控件提供的对外接口的调用,隐藏了TCP/IP的实际实现过程,直接实现文件传输。程序采用客户机/服务器体系,服务器侦听连接请求,客户机发起请求,客户机与服务器合作实现文件的双向传输。%TCP/IP is base protocol of Internet. The article of Remote File Transport is base on TCP/IP protocol, Using the control of programmable language Delphi, Because all function of implementation are encapsulated in activeX control, application program interface can be invoked easily, Executing TCP/IP function is hid, So finishing remote file transport .The program use Client/Server system. Server listen in to Client requesting,Client sent request ,Client and Server can work well together to accomplish the file bidirectional transportation.

  17. TCP Freeze-Probing Enhancement for Mobile Ad Hoc Networks%基于无线自组织网络的TCP Freeze-Probing改进协议

    Institute of Scientific and Technical Information of China (English)

    王波; 范平志

    2005-01-01

    传统的TCP协议在有线网络中能够良好地工作,但用于无线自组织网络时则性能有所下降.其原因在于,传统的TCP协议无法分辨网络丢包原因,如网络拥塞、链路断开、信道错误或者链路改变.为了提高TCP协议在无线自组织网络中的性能,提出了一种TCP协议的改进方案TCP Freeze-Probing.该方案是一种端到端方法,不需要网络中间节点的反馈合作同时,提出了一种基于TCP Freeze-Probing的吞吐量模型并利用仿真对模型进行了验证.分析和仿真结果表明,该方案能够有效地改进TCP在无线自组织网络的性能.%Traditional Transmission Control Protocol (TCP) works well in wired network but suffers from performance degradation in mobile ad-hoc networks (MANET) due to the fact that it cannot distinguish packet losses due to congestion from packet losses due to link breakage, channel error and route changes. In this paper, an enhanced TCP, named TCP Freeze-Probing, is proposed to improve the TCP performance in mobile ad-hoc networks. TCP Freeze-Probing is an end-to-end approach that does not need the cooperation of the intermediate nodes in the network. Besides, a throughput model for TCP Freeze-Probing is given, which is validated through simulation. It is shown by analysis and simulation that the proposed approach can greatly improve the TCP performance in MANET.

  18. 无线网络中TCP/NC协议性能分析与仿真验证%Performance Analysis and Simulation Verification of TCP/NC Protocol in Wireless Network

    Institute of Scientific and Technical Information of China (English)

    葛卫民; 朱海颖; 李娟

    2015-01-01

    In order to improve the traditional Transmission Control Protocol( TCP) performance in wireless networks, this paper solves throughput rate model of three TCP protocols,TCP Reno,TCP Vegas and TCP/NC based on network coding through Matlab,and analyzes the theoretical value of the three models in different networks,and verifies whether TCP/NC model can improve its throughput rate. The three models are simulated through NS-2,and simulation results show the effectiveness of TCP/NC protocol and its analysis model.%为改进传统传输控制协议( TCP)在无线网络中的性能,运用Matlab对TCP Reno,TCP Vegas和基于网络编码的TCP/NC吞吐率分析模型进行数值求解,分析3个模型在不同网络环境下应达到的理论值,验证TCP/NC模型在理论上能否提高其吞吐率。基于NS-2对3种吞吐率模型进行仿真,结果表明,TCP/NC及其分析模型可有效改进TCP协议。

  19. Sister Carrie in China

    Institute of Scientific and Technical Information of China (English)

    殷希

    2015-01-01

    Sister Carrie has received many Chinese scholar's attention, and it has quantity relevance researches. Therefore, it is valuable to study why it is popular in China and it's education meaning for Chinese people. In addition, to analysis the domestic re-searches and find it's exist problems can help us make a new breakthrough from the study.

  20. Role of UV photolysis in accelerating the biodegradation of 2,4,6-TCP.

    Science.gov (United States)

    Wang, Wenbing; Kirumba, George; Zhang, Yongming; Wu, Yanqing; Rittmann, Bruce E

    2015-09-18

    2,4,6-TCP, a kind of chlorinated aromatic and aliphatic compound, is difficult to be biodegraded by ordinary microorganisms. UV photolysis and biodegradation of 2,4,6-TCP by Bacillus amyloliquefaciens intimate coupling is a potential means to accelerate its biotransformation. The initial steps of 2,4,6-TCP biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. It was demonstrated that B. amyloliquefaciens has the 2,4,6-TCP monooxygenase gene tcpA which could encode 2,4,6-TCP monooxygenase (TCP-MO). TCP-MO would catalytically decompose 2,4,6-TCP into 2,6-DCHQ. We employed an internal loop photolytic biofilm reactor for 2,4,6-TCP degradation. Sequentially coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P + B (TCP(UV) + phenol) protocol was higher by 77 and 103 % when compared to B (TCP + phenol) and B (TCP-only) protocols respectively. The corresponding loss rate coefficient (k) values were 0.069, 0.039, 0.034 mg/L·min(-1) respectively. This is because UV photolysis converted 2,4,6-TCP into its intermediates: 2,4-dichlorophenol (2,4-DCP), 4-monochlorophenol (4-MCP), phenol, 2,6-dichloro-p-hydroquinone (2,6-DCHQ), with all displaying less inhibition to bacterial action. In addition, phenol was the crucial UV-photolysis product from 2,4,6-TCP, its catabolic oxidation generating internal electron carriers that may accelerate the initial steps of 2,4,6-TCP biodegradation. Intimately coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P&B (TCP + phenol) protocol was higher by 166 and 681 % when compared to P&B (TCP-only) and P + B protocols respectively. The corresponding loss rate coefficient (k) values were 0.539, 0.203, 0.069 mg/L·min(-1) respectively. It provided sufficient evidence to demonstrate that intimately coupled photolysis and biodegradation accelerated 2,4,6-TCP

  1. Comparison of TCP automatic tuning techniques for distributed computing

    Energy Technology Data Exchange (ETDEWEB)

    Weigle, E. H. (Eric H.); Feng, W. C. (Wu-Chun)

    2002-01-01

    Rather than painful, manual, static, per-connection optimization of TCP buffer sizes simply to achieve acceptable performance for distributed applications, many researchers have proposed techniques to perform this tuning automatically. This paper first discusses the relative merits of the various approaches in theory, and then provides substantial experimental data concerning two competing implementations - the buffer autotuning already present in Linux 2.4.x and 'Dynamic Right-Sizing.' This paper reveals heretofore unknown aspects of the problem and current solutions, provides insight into the proper approach for various circumstances, and points toward ways to further improve performance. TCP, for good or ill, is the only protocol widely available for reliable end-to-end congestion-controlled network communication, and thus it is the one used for almost all distributed computing. Unfortunately, TCP was not designed with high-performance computing in mind - its original design decisions focused on long-term fairness first, with performance a distant second. Thus users must often perform tortuous manual optimizations simply to achieve acceptable behavior. The most important and often most difficult task is determining and setting appropriate buffer sizes. Because of this, at least six ways of automatically setting these sizes have been proposed. In this paper, we compare and contrast these tuning methods. First we explain each method, followed by an in-depth discussion of their features. Next we discuss the experiments to fully characterize two particularly interesting methods (Linux 2.4 autotuning and Dynamic Right-Sizing). We conclude with results and possible improvements.

  2. Characterization of TCP-1 probes for molecular imaging of colon cancer.

    Science.gov (United States)

    Liu, Zhonglin; Gray, Brian D; Barber, Christy; Bernas, Michael; Cai, Minying; Furenlid, Lars R; Rouse, Andrew; Patel, Charmi; Banerjee, Bhaskar; Liang, Rongguang; Gmitro, Arthur F; Witte, Marlys H; Pak, Koon Y; Woolfenden, James M

    2016-10-10

    Molecular probes capable of detecting colorectal cancer (CRC) are needed for early CRC diagnosis. The objective of this study was to characterize c[CTPSPFSHC]OH (TCP-1), a small peptide derived from phage display selection, for targeting human CRC xenografts using technetium-99m ((99m)Tc)-labeled TCP-1 and fluorescent cyanine-7 (Cy7)-labeled form of the peptide (Cy7-TCP-1). (99m)Tc-TCP-1 was generated by modifying TCP-1 with succinimidyl-6-hydrazino-nicotinamide (S-HYNIC) followed by radiolabeling. In vitro saturation binding experiments were performed for (99m)Tc-TCP-1 in human HCT116 colon cancer cells. SCID mice with human HCT116 cancer xenografts were imaged with (99m)Tc-TCP-1 or control peptide using a small-animal SPECT imager: Group I (n=5) received no blockade; Group II (n=5) received a blocking dose of non-radiolabeled TCP-1. Group III (n=5) were imaged with (99m)Tc-labeled control peptide (inactive peptide). SCID mice with human PC3 prostate cancer xenografts (Group IV, n=5) were also imaged with (99m)Tc-TCP-1. Eight additional SCID mice bearing HCT116 xenografts in dorsal skinfold window chambers (DSWC) were imaged by direct positron imaging of (18)F-fluorodeoxyglucose ((18)F-FDG) and fluorescence microscopy of Cy7-TCP-1. In vitro(99m)Tc-HYNIC-TCP-1 binding assays on HCT 116 cells indicated a mean Kd of 3.04±0.52nM. In cancer xenografts, (99m)Tc-TCP-1 radioactivity (%ID/g) was 1.01±0.15 in the absence of blockade and was reduced to 0.26±0.04 (PTCP-1 or HCT116 tumors with inactive peptide. Cy7-TCP-1 activity localized not only in metabolically active tumors, as defined by (18)F-FDG imaging, but also in peritumoral microvasculature. In conclusion, TCP-1 probes may have a distinct targeting mechanism with high selectivity for CRC and tumor-associated vasculature. Molecular imaging with TCP-1 probes appears promising to detect malignant colorectal lesions.

  3. TCP- Costco Reno: New Variant by Improving Bandwidth Estimation to adapt over MANETs

    Directory of Open Access Journals (Sweden)

    Prakash B. Khelage

    2014-01-01

    Full Text Available The Transmission Control Protocol (TCP is traditional, dominant and has been de facto standard protocol, used as transport agent at transport layer of TCP/IP protocol suite. Basically it is designed to provide reliability and assure guaranty to end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless Ad Hoc Networks, therefore it can lead to TCP implementations with poor performance. The problem of TCP and all its existing variations within MANETs resides in its inability to distinguish between different data packet loss causes, whenever the data loss occur traditional TCP congestion control algorithm assumes loss is due to congestion episode and reduces sending parameters value unnecessary. Thus, TCP has not always the optimum behavior in front of packet losses which might cause network performance degradation and resources waste. In order to adapt TCP over mobile Ad hoc environment, improvements have been proposed based on RTT and BW estimation technique in the literature to help TCP to differentiate accurate causes between the different types of losses. But still does not handle all the problems accurately and effectively. In this paper, a proposed TCP-Costco Reno a New Variant, accurately estimates the available bandwidth over Mobile Ad Hoc networks and sets sending rate accordingly to maximize utilization of available resources and hence improves performance of TCP over mobile Ad hoc networks. The results of the simulation indicate an improvement in throughput over interference, link failure and signal loss validation scenarios. Further, it shows highest average of average throughput then those variants which are most successful over MANETs.

  4. Un nuevo ataque a TCP para redes de radios cognitivas

    OpenAIRE

    León Abarca, Olga; Hernández Serrano, Juan; Soriano Ibáñez, Miguel

    2009-01-01

    Los dispositivos de radios cognitivas emergen como una prometedora tecnología que ha de permitir un mejor uso del espectro electro-magnético. Estos dispositivos se caracterizan por ser capaces de observar y entender su entorno, y cambiar consecuentemente su modo de operación. Sin embargo, estas propiedades “cognitivas” conllevan nuevos retos de seguridad. En este artículo se presenta un nuevo ataque a las conexiones TCP en redes de radios cognitivas, se proponen soluciones para mitigarlo y se...

  5. The CASCAM network control system based on TCP/IP

    Science.gov (United States)

    Ren, S. B.; Yao, Y. Q.; Yao, D. Z.

    2004-05-01

    The paper presents the CASCAM network control system based on the TCP/IP protocol. In order to realize the Client/Server model in network communication between the workstation and personal computer efficiently, two C++ classes, client and server, were developed in the system. The script language Tcl/Tk was used in programming the system control pane in the Client. With loading the dynamic library, the Client sends the request to the Server through the network, then the Server analyzes the request and controls the camera system.

  6. Embedded TCP/IP Chip Based on DW8051 Core

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As remote control for electric home appliances thro ug h the Internet becomes more common, many compannies today launched a new corpora te initiative to develop advanced embedded solutions for Internet connectivity t hat can be applied to a boundless number of products such as information applian ces and non-PC devices. The most representative products are CMX-MicroNet which provides true TCP/IP ca pabilities for 8-bit and 16-bit microprocessors and eZ80Internet Engine which provides easy Internet connect...

  7. Loss Strategies for Competing TCP/IP Connections

    OpenAIRE

    Altman, Eitan; El-Azouzi, Rachid; Ros, David; Tuffin, Bruno

    2004-01-01

    We study in this paper two competing TCP connections that share a common bottleneck link. When congestion occurs, one (or both) connections will suffer a loss that will cause its throughput to decrease by a multiplicative factor. The identity of the connection that will suffer a loss is determined by a randomized «loss strategy» that may depend on the throughputs of the connections at the congestion instant. We analyze several loss strategies: the one in which the identity of loss is independ...

  8. Turning Traffic Jams to Jelly

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Beijing, known for having the worst traffic in China, is brewing up a traffic plan with the harshest ever measures to ensure smooth traffic flow as the capital’s gridlock during rush hour and private car sales soar.

  9. Road Traffic in China

    NARCIS (Netherlands)

    Jie, L.; Van Zuylen, H.J.

    2014-01-01

    Traffic is tightly related to the social and economic development in a country. In China the development of the economy has been very fast in the past 30 years and this is still continuing. The transport infrastructure shows a similar pattern, while traffic is also rapidly growing. In urban areas th

  10. Distraction in traffic.

    NARCIS (Netherlands)

    2013-01-01

    Many drivers, as well as cyclists and pedestrians, are occupied with all kinds of activities that can distract their attention from traffic, like listening to music, conducting a conversation on their mobile phone, or texting. Distraction has negative effects on traffic behaviour. Most studies estim

  11. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  12. Traffic Light Options

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte

    2007-01-01

    This paper introduces, prices, and analyzes traffic light options. The traffic light option is an innovative structured OTC derivative developed independently by several London-based investment banks to suit the needs of Danish life and pension (L&P) companies, which must comply with the traffic...... light solvency stress test system introduced by the Danish Financial Supervisory Authority (DFSA) in June 2001. This monitoring system requires L&P companies to submit regular reports documenting the sensitivity of the companies' base capital to certain pre-defined market shocks - the red and yellow...... light scenarios. These stress scenarios entail drops in interest rates as well as in stock prices, and traffic light options are thus designed to pay off and preserve sufficient capital when interest rates and stock prices fall simultaneously. Sweden's FSA implemented a traffic light system in January...

  13. Properties of Traffic Risk Coefficient

    Institute of Scientific and Technical Information of China (English)

    TANG Tie-Qiao; HUANG Hai-Jun; SHANG Hua-Yan; XUE Yu

    2009-01-01

    We use the model with the consideration of the traffic interruption probability (Physica A 387(2008)6845) to study the relationship between the traffic risk coefficient and the traffic interruption probability.The analytical and numerical results show that the traffic interruption probability will reduce the traffic risk coefficient and that the reduction is related to the density, which shows that this model can improve traffic security.

  14. TCP/IP Protocols Analysis and Program About Communication Application%TCP/IP协议分析及通信应用编程

    Institute of Scientific and Technical Information of China (English)

    狄博

    2006-01-01

    分析了TCP/IP协议的体系结构、组成与功能以及通过TCP/IP协议实现异构型网络互连的机理.对TCP/IP协议提供的两种通信功能进行了分析,辩证地提出了它们不同的应用场合.最后,给出了在TCP/IP基础上开发通信应用程序的编程模型和实现要点,对用户开发应用程序有一定参考意义.

  15. A macroscopic model of traffic jams in axons.

    Science.gov (United States)

    Kuznetsov, A V; Avramenko, A A

    2009-04-01

    The purpose of this paper is to develop a minimal macroscopic model capable of explaining the formation of traffic jams in fast axonal transport. The model accounts for the decrease of the number density of positively (and negatively) oriented microtubules near the location of the traffic jam due to formation of microtubule swirls; the model also accounts for the reduction of the effective velocity of organelle transport in the traffic jam region due to organelles falling off microtubule tracks more often in the swirl region. The model is based on molecular-motor-assisted transport equations and the hydrodynamic model of traffic jams in highway traffic. Parametric analyses of the model's predictions for various values of viscosity of the traffic flow, variance of the velocity distribution, diffusivity of microtubule-bound and free organelles, rate constants for binding to and detachment from microtubules, relaxation time, and average motor velocities of the retrograde and anterograde transport, are carried out.

  16. Functionally graded PCL/ β-TCP biocomposites in a multilayered structure for bone tissue regeneration

    Science.gov (United States)

    Kim, Yong Bok; Kim, GeunHyung

    2012-09-01

    Functionally graded (FG) composites consisting of polycaprolactone (PCL) and beta-tricalcium phosphate ( β-TCP) particles were fabricated with a multilayered structure using a melt plotter with a two-heating-barrel system. Using this process, the concentration of β-TCP particles varied in each layered strut. Scanning electron microscopy (SEM) and energy dispersive spectroscopy mapping of calcium on the fabricated scaffolds indicated that the β-TCP particles were well distributed in each PCL strut, according to conceptual design. By incorporating β-TCP, the FG-PCL/ β-TCP scaffolds had meaningful increases in water absorption (30 % increase) and showed good mechanical properties, although the mechanical properties are slightly low compared to pure PCL/ β-TCP composite. We performed biological assessments to evaluate the capability of these FG scaffolds to act as a biomaterial for bone tissue regeneration with osteoblast-like cells (MG63). SEM images of cell-seeded FG scaffolds showed that the concentrated β-TCP struts were affected as good cell attachment/proliferation sites. Additionally, calcium deposition on the FG scaffolds was higher than that of normal scaffolds after 14 days. In particular, we observed high levels of mineralization in the highly concentrated β-TCP struts in the FG scaffolds. Based on these results, we believe that the FG scaffolds having various spatially designed structures with graded properties will be widely applicable for hard tissue engineering applications.

  17. Method to enhance the TCP performance in managed buffer handover for mobile IPv6

    Science.gov (United States)

    Kan, Zhigang; Ma, Jian; Yuan, Man; Luo, Jun

    2002-08-01

    The paper is related to TCP performance enhancement in Buffer Management of Mobile IPv6 where transmission control protocol is used as transport layer protocol. A mechanism that improves TCP performance in buffer management for Mobile IPv6 is proposed when handovers are normally taken place. By this mechanism, MB-aware routers can send

  18. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

    Science.gov (United States)

    Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

    2017-01-01

    The Internet of Things (IoT) has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem. PMID:28075347

  19. The battle between standards: TCP/IP vs OSI victory through path dependency or by quality?

    NARCIS (Netherlands)

    Maathuis, I.J.H.; Smit, W.A.; Egyedi, T.M.; Krechmer, K.; Jakobs, K.

    2003-01-01

    Between the end of the 1970s and 1994 a fierce competition existed between two possible standards, TCP/IP and OSI, to solve the problem of interoperability of computer networks. Around 1994 it became evident that TCP/IP and not OSI had become the dominant standard. We specifically deal with the ques

  20. TCP and web browsing performance in case of bi-directional packet loss

    NARCIS (Netherlands)

    Kooij, R.E.; Mei, R.D. van der; Yang, R.

    2010-01-01

    Performance modeling of the transport control protocol (TCP) has received a lot of attention over the past few years. The most commonly quoted results are approximate formulas for TCP throughput (Padhye et al. (2000) [1]) and document download times (Cardwell et al. (2000) [2]) which are used for di

  1. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications.

    Science.gov (United States)

    Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

    2017-01-08

    The Internet of Things (IoT) has gained popularity in recent years. Today's IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

  2. DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL (TCP) BY ELISA

    Science.gov (United States)

    A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for 3,5,6-trichloro-2pyridinol (TCP) has been developed to quantitate parts per billion (ppb) amounts of the analyte in urine. TCP is a major metabolite and environmental degradation product of the insecticide c...

  3. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

    Directory of Open Access Journals (Sweden)

    Yifei Lu

    2017-01-01

    Full Text Available The Internet of Things (IoT has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN, TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

  4. Cross-layer TCP Performance Analysis in IEEE 802.11 Vehicular Environments

    Directory of Open Access Journals (Sweden)

    T. Janevski

    2014-06-01

    Full Text Available In this paper we provide a performance analysis of TCP in IEEE 802.11 vehicular environments for different well-known TCP versions, such as Tahoe, Reno, New Reno, Vegas, and Sack. The parameters of interest from the TCP side are the number of Duplicate Acknowledgements - DupAck, and the number of Delayed Acknowledgements - DelAck, while on the wireless network side the analyzed parameter is the interface queue - IFQ. We have made the analysis for the worst-case distance scenario for single-hop and worst-case multihop vehicular environments. The results show that the number of wireless hops in vehicular environments significantly reduces the TCP throughput. The best average performances considering all scenarios were obtained for TCP Vegas. However, the results show that the interface queue at wireless nodes should be at least five packets or more. On the other side, due to shorter distances in the vehicular wireless network, results show possible flexibility of using different values for the DupAck without degradation of the TCP throughput. On the other side, the introduction of the DelAck parameter provides enhancement in the average TCP throughput for all TCP versions.

  5. Efficient IP Traffic over Optical Network Based on Wavelength Translation Switching

    DEFF Research Database (Denmark)

    Jha, Vikas; Kalia, Kartik; Chowdhary, Bhawani Shankar;

    2016-01-01

    With the advent of TCP/IP protocol suite the overall era of communication technologies had been redefined. Now, we can’t ignore the presence of huge amount of IP traffic; data, voice or video increasing day by day creating more pressure on existing communicating media and supporting back bone....... With the humongous popularity of Internet the overall traffic on Internet has the same story. Focusing on transmission of IP traffic in an optical network with signals remaining in their optical nature generated at particular wavelength, proposed is the switching of optically generated IP packets through optical...... cross connects based on translation of wavelength when an IP packet is crossing the optical cross connect. Adding the concepts of layer 3 routing protocols along with the wavelength translation scheme, will help in spanning the overall optical network for a larger area....

  6. 在TMS320DM642上实现嵌入式TCP/IP协议栈%Embedded Solution of TCP/IP Protocol Stack Based on TMS320DM642

    Institute of Scientific and Technical Information of China (English)

    王平; 孙乐美

    2007-01-01

    实现了一个运行在数字信号处理器TMS320DM642上的嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议进行分析,完成基于TCP/IP协议的嵌入式网络系统.

  7. 49 CFR 1.50 - Delegation to the National Highway Traffic Safety Administrator.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Delegation to the National Highway Traffic Safety... DELEGATION OF POWERS AND DUTIES Delegations § 1.50 Delegation to the National Highway Traffic Safety Administrator. The National Highway Traffic Safety Administrator is delegated authority to: (a) Carry out...

  8. Covert Channels Based on the TCP/IP Header Information%基于TCP/IP包头的隐藏通道技术

    Institute of Scientific and Technical Information of China (English)

    杨忠仪; 章正辉

    2006-01-01

    随着信息技术的发展,网络通信安全已经成为安全领域的一个重要内容.本文详细介绍了三种基于TCP/IP包头信息隐蔽传输数据的方法,并就Windows平台阐述了利用TCP/IP包头进行信息隐蔽传输的实现.

  9. Research on the Congest Control Algorithm of TCP/IP%基于TCP/IP拥塞控制的算法研究

    Institute of Scientific and Technical Information of China (English)

    李学渊

    2005-01-01

    在WPAN上使用TCP的关键在于拥塞控制,根据TCP的拥塞控制机制,通过分析拥塞控制的闭环控制原理、TCP/IP拥塞控制所使用的典型技术,研究TCP/IP拥塞控制在无线网上应用的算法.

  10. TCP/IP Protocol Security and IP Layer Encryption Technology%TCP/IP协议安全与IP层加密技术

    Institute of Scientific and Technical Information of China (English)

    谭兴烈

    2001-01-01

    @@ 由于互联网的广泛使用和TCP/IP协议在全球的风靡,对IP层安全处理技术的研究及在IP层开发的安全产品层出不穷,IP层安全成为一个受到广泛关注的问题,因此研究IP层的安全体系十分重要.TCP/IP协议的安全

  11. Evaluation of replacement protocols and modifications to TCP to enhance ASC Wide Area Network performance.

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Randy L. Jr.

    2004-09-01

    Historically, TCP/IP has been the protocol suite used to transfer data throughout the Advanced Simulation and Computing (ASC) community. However, TCP was developed many years ago for an environment very different from the ASC Wide Area Network (WAN) of today. There have been numerous publications that hint of better performance if modifications were made to the TCP algorithms or a different protocol was used to transfer data across a high bandwidth, high delay WAN. Since Sandia National Laboratories wants to maximize the ASC WAN performance to support the Thor's Hammer supercomputer, there is strong interest in evaluating modifications to the TCP protocol and in evaluating alternatives to TCP, such as SCTP, to determine if they provide improved performance. Therefore, the goal of this project is to test, evaluate, compare, and report protocol technologies that enhance the performance of the ASC WAN.

  12. Effect of β-TCP Ceramic on the Total Protein of Osteoblasts

    Institute of Scientific and Technical Information of China (English)

    QI Zhitao; DAI Honglian; ZHANG qihuan; CAO Xianying; LI Shipu

    2007-01-01

    The osteoblast with the β-TCP ceramic was co-cultured. Scanning electron microscopy shows the cells adhered onto β-TCP ceramic surface and grew better, proving the β-TCP ceramic has a biocompatible property. The Coomassie brilliant blue G-250 stain shows that the total protein in the experimental groups was highly increased compared with the control group (p<0.05). Flow-cytometric analysis shows that β-TCP ceramic could promote the osteoblast transform from the G0/G1 phase to S phase. Those all demonstrate the product of the degradation of the β-TCP ceramic may take part in the protein metabolism of osteoblast.

  13. Model Based System Engineering Approach of a Lightweight Embedded TCP/IP

    Directory of Open Access Journals (Sweden)

    M. Z. Rashed

    2011-04-01

    Full Text Available The use of embedded software is growing very rapidly. Accessing the internet is a necessaryservice which has large range of applications in many fields. The Internet is based on TCP/IPwhich is a very important stack. Although TCP/IP is very important there is not a softwareengineering model describing it. The common method in modeling and describing TCP/IP is RFCswhich is not sufficient for software engineer and developers. Therefore there is a need for softwareengineering approach to help engineers and developers to customize their own web basedapplications for embedded systems.This research presents a model based system engineering approach of lightweight TCP/IP. Themodel contains the necessary phases for developing a lightweight TCP/IP for embedded systems.The proposed model is based on SysML as a model based system engineering language.

  14. A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The IP-based networks on aircraft serve to support Internet services via satellites. However, in aeronautical satellite hybrid networks, the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism (OGBM), which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver's advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to 1 improves TCP performance in aeronautical satellite networks.

  15. TCP three-way handshake: linking developmental processes with plant immunity.

    Science.gov (United States)

    Lopez, Jessica A; Sun, Yali; Blair, Peter B; Mukhtar, M Shahid

    2015-04-01

    The TCP gene family encodes plant-specific transcription factors involved in growth and development. Equally important are the interactions between TCP factors and other pathways extending far beyond development, as they have been found to regulate a variety of hormonal pathways and signaling cascades. Recent advances reveal that TCP factors are targets of pathogenic effectors and are likely to play a vital role in plant immunity. Our focus is on reviewing the involvement of TCP in known pathways and shedding light on other linkages in the nexus of plant immunity centered around TCP factors with an emphasis on the convergence of effectors, interconnected hormonal networks, utility of the circadian clock, and the potential mechanisms by which pathogen defense may occur.

  16. Application of stochastic discrete event system framework for detection of induced low rate TCP attack.

    Science.gov (United States)

    Barbhuiya, F A; Agarwal, Mayank; Purwar, Sanketh; Biswas, Santosh; Nandi, Sukumar

    2015-09-01

    TCP is the most widely accepted transport layer protocol. The major emphasis during the development of TCP was its functionality and efficiency. However, not much consideration was given on studying the possibility of attackers exploiting the protocol, which has lead to several attacks on TCP. This paper deals with the induced low rate TCP attack. Since the attack is relatively new, only a few schemes have been proposed to mitigate it. However, the main issues with these schemes are scalability, change in TCP header, lack of formal frameworks, etc. In this paper, we have adapted the stochastic DES framework for detecting the attack, which addresses most of these issues. We have successfully deployed and tested the proposed DES based IDS on a test bed.

  17. Efficient Frame Schedule Scheme for Real-time Video Transmission Across the Internet Using TCP

    Directory of Open Access Journals (Sweden)

    Yonghua Xiong

    2009-05-01

    Full Text Available The great end-to-end delays are the major factor to influence the visual quality of real-time video across the Internet using TCP as transport layer protocol. In this paper, we present a video frame schedule scheme for rate adaptive real-time video transmission over TCP. The scheme schedules video frames between the application layer sender-buffer, the TCP sender-buffer and TCP receiver-buffer and can regulate automaticlly the video frame rate and play out buffer delays according to the network congestion level. The sheme requires only an extra buffer of application layer and can significantly cut down the end-to-end delays of real-time video without any modification to the network infrastructure or TCP protocol stack. The performance of the proposed solution is evaluated through extensive simulations using the NS-2 simulator.

  18. Calorimetry investigations of milled α-tricalcium phosphate (α-TCP) powders to determine the formation enthalpies of α-TCP and X-ray amorphous tricalcium phosphate.

    Science.gov (United States)

    Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

    2015-09-01

    One α-tricalcium phosphate (α-TCP) powder was either calcined at 500°C to obtain fully crystalline α-TCP or milled for different durations to obtain α-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71wt.% ATCP and up to 2.0±0.1wt.% β-TCP as minor phase were then hydrated in 0.1M Na2HPO4 aqueous solution and the resulting heat flows were measured by isothermal calorimetry. Additionally, the evolution of the phase composition during hydration was determined by in situ XRD combined with the G-factor method, an external standard method which facilitates the indirect quantification of amorphous phases. Maximum ATCP hydration was reached after about 1h, while that of crystalline α-TCP hydration occurred between 4 and 11h, depending on the ATCP content. An enthalpy of formation of -4065±6kJ/mol (T=23°C) was calculated for ATCP (Ca3(PO4)2), while for crystalline α-TCP (α-Ca3(PO4)2) a value of -4113±6kJ/mol (T=23°C) was determined.

  19. ¿Hacia una Nueva Arquitectura Financiera Regional? Problemas y perspectivas de la cooperación monetaria en el ALBA-TCP

    Directory of Open Access Journals (Sweden)

    Benzi, D.

    2016-05-01

    Full Text Available This paper addresses the experiences of the monetary and financial cooperation carried out within the framework of ALBA-TCP. The first part describes the context of global crisis and emerging multipolarity in which the debate on the reform of the International Financial Architecture (IFA and regional monetary initiatives are inserted. The second part revises the Latin American initiative of a New Regional Financial Architecture. Later, we analyze the origins, processes and effects of mechanisms implemented within the ALBA-TCP, such as the ALBA Bank and the SUCRE. Finally, the essay concludes by presenting both potential and limitations of these experiences within a regional and global scenario marked by a high degree of uncertainty that, paradoxically so far, seems to delay and inhibit rather than consolidate the strengthening of a New Regional Financial Architecture.

  20. The Putative O-Linked N-Acetylglucosamine Transferase SPINDLY Inhibits Class I TCP Proteolysis to Promote Sensitivity to Cytokinin.

    Science.gov (United States)

    Steiner, Evyatar; Livne, Sivan; Kobinson-Katz, Tammy; Tal, Lior; Pri-Tal, Oded; Mosquna, Assaf; Tarkowská, Danuše; Mueller, Bruno; Tarkowski, Petr; Weiss, David

    2016-06-01

    Arabidopsis (Arabidopsis thaliana) SPINDLY (SPY) is a putative serine and threonine O-linked N-acetylglucosamine transferase (OGT). While SPY has been shown to suppress gibberellin signaling and to promote cytokinin (CK) responses, its catalytic OGT activity was never demonstrated and its effect on protein fate is not known. We previously showed that SPY interacts physically and functionally with TCP14 and TCP15 to promote CK responses. Here, we aimed to identify how SPY regulates TCP14/15 activities and how these TCPs promote CK responses. We show that SPY activity is required for TCP14 stability. Mutation in the putative OGT domain of SPY (spy-3) stimulated TCP14 proteolysis by the 26S proteasome, which was reversed by mutation in CULLIN1 (CUL1), suggesting a role for SKP, CUL1, F-box E3 ubiquitin ligase in TCP14 proteolysis. TCP14 proteolysis in spy-3 suppressed all TCP14 misexpression phenotypes, including the enhanced CK responses. The increased CK activity in TCP14/15-overexpressing flowers resulted from increased sensitivity to the hormone and not from higher CK levels. TCP15 overexpression enhanced the response of the CK-induced synthetic promoter pTCS to CK, suggesting that TCP14/15 affect early steps in CK signaling. We propose that posttranslational modification of TCP14/15 by SPY inhibits their proteolysis and that the accumulated proteins promote the activity of the CK phosphorelay cascade in developing Arabidopsis leaves and flowers.

  1. Preparation and Characterization ofβ-TCP/CS Scaffolds by Freeze-extraction and Freeze-gelation

    Institute of Scientific and Technical Information of China (English)

    HAO Ruiran; WANG Deping; YAO Aihua; HUANG Wenhai

    2011-01-01

    The freeze-extraction and freeze-gelation methods were used to prepare highly porous β-TCP/CS scaffolds with different β-TCP/CS ratio. In these methods, the suspending mixture of β-TCP and chitosan was frozen, the frozen mixture was immersed in a non-solvent(0.05 mol/L NaOH/ehanol aqueous) bath to allow the exchange between solvent(acetic-acid aqueous) and non-solvent at a temperature lower than the freezing point of the acetic-acid. Then, the β-TCP/CS scaffolds were formed and dried at room temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), gas chromatography (GC) and omnipotence material testing machine were employed to characterize theβ-TCP/CS scaffolds. The results of GC show that the freeze extraction of the β-TCP/chitosan scaffolds was completed when the extraction time is above 24 h. The SEM results show that the β-TCP/CS scaffolds are composed of interconnected pore network. The porosity of the β-TCP/CS scaffolds decrease with the increase of the content of the β-TCP. The β-TCP/CS scaffolds have a highest compressive strength when the chitosan/β-TCP ratio is 30:70. The present work displays that the β-TCP/CS composite scaffolds with appropriate mechanical properties and high porosity can be successfully prepared by the freeze-extraction and freeze-gelation methods.

  2. Hierarchical structures of β-TCP/45S5 bioglass hybrid scaffolds prepared by gelcasting.

    Science.gov (United States)

    Lopes, João Henrique; Magalhães, Jéssica Aparecida; Gouveia, Rubia Figueredo; Bertran, Celso Aparecido; Motisuke, Mariana; Camargo, Samira E A; Trichês, Eliandra de Sousa

    2016-09-01

    This paper investigates the microstructure and the mechanical properties of β-tricalcium phosphate (β-TCP) three-dimensional (3D) porous materials reinforced with 45S5 bioactive glass (BG). β-TCP and β-TCP/x%-BG scaffolds with interconnected pores networks, suitable for bone regeneration, were fabricated by gel-casting method. Mechanical properties, porosity, and morphological characteristics were evaluated by compressive strength test, scanning electron microscopy (SEM) and X-ray microtomography analysis, whereas the structures were fully explored by XRD, and Raman spectroscopy. To the best of our knowledge, this is the first time where the mechanism for understanding the effect of bioglass on the mechanical properties and microstruture of β-TCP/45S5-BG scaffolds has been systematically studied. The findings showed that ionic product lixiviated from 45S5 bioactive glass, rich in silicon species and sodium ion, catalyzes a phase transition from β-TCP to Si-TCP by replacement of phosphorus for silicon and contributes to the improvement of scaffolds mechanical properties. The compressive strength of β-TCP/5%-BG and β-TCP/7.5%-BG was improved around 200% in comparison to pure β-TCP. Osteoblast-like cells (MG 63) were exposed to the materials for 24h through the use of medium conditioned by β-tricalcium phosphate/bioactive glass. Cell viability was measured by MTT assay in the cells and the data obtained were submitted to ANOVA, Tukey׳s multiple comparison (pTCP/7.5-BG promoted an increase of cell proliferation. The results suggest that compositions and processing method studied may provide appropriate materials for tissue engineering.

  3. Identification and Transcript Analysis of the TCP Transcription Factors in the Diploid Woodland Strawberry Fragaria vesca

    Science.gov (United States)

    Wei, Wei; Hu, Yang; Cui, Meng-Yuan; Han, Yong-Tao; Gao, Kuan; Feng, Jia-Yue

    2016-01-01

    Plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, and PROLIFERATING CELL FACTORS (TCP) transcription factors play versatile functions in multiple processes of plant growth and development. However, no systematic study has been performed in strawberry. In this study, 19 FvTCP genes were identified in the diploid woodland strawberry (Fragaria vesca) accession Heilongjiang-3. Phylogenetic analysis suggested that the FvTCP genes were classified into two main classes, with the second class further divided into two subclasses, which was supported by the exon-intron organizations and the conserved motif structures. Promoter analysis revealed various cis-acting elements related to growth and development, hormone and/or stress responses. We analyzed FvTCP gene transcript accumulation patterns in different tissues and fruit developmental stages. Among them, 12 FvTCP genes exhibited distinct tissue-specific transcript accumulation patterns. Eleven FvTCP genes were down-regulated in different fruit developmental stages, while five FvTCP genes were up-regulated. Transcripts of FvTCP genes also varied with different subcultural propagation periods and were induced by hormone treatments and biotic and abiotic stresses. Subcellular localization analysis showed that six FvTCP-GFP fusion proteins showed distinct localizations in Arabidopsis mesophyll protoplasts. Notably, transient over-expression of FvTCP9 in strawberry fruits dramatically affected the expression of a series of genes implicated in fruit development and ripening. Taken together, the present study may provide the basis for functional studies to reveal the role of this gene family in strawberry growth and development. PMID:28066489

  4. VBR video traffic models

    CERN Document Server

    Tanwir, Savera

    2014-01-01

    There has been a phenomenal growth in video applications over the past few years. An accurate traffic model of Variable Bit Rate (VBR) video is necessary for performance evaluation of a network design and for generating synthetic traffic that can be used for benchmarking a network. A large number of models for VBR video traffic have been proposed in the literature for different types of video in the past 20 years. Here, the authors have classified and surveyed these models and have also evaluated the models for H.264 AVC and MVC encoded video and discussed their findings.

  5. Road Traffic Injuries

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-guo

    2005-01-01

    @@ As everybody knows that automobiles have been greatly changing our life. However, everything has two sides, motor vehicles have also caused a huge number of people's deaths, injuries and property damage. Traffic crashes are perhaps the number one public health problem in developed countries [1]. In the United States, pre-retirement years of life lost in traffic crashes are more than that of the two combined leading diseases: cancer and heart disease [1]. Today road traffic crash (RTC) ranks 11th in leading cause of death and accounts for 2.1% of all deaths globally.

  6. Turning Traffic Jams to Jelly

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ Beijing, known for having the worst traffic in China, is brewing up a traffic plan with the harshest ever measures to ensure smooth traffic flow as the capital's gridlock during rush hour and private car sales soar. On December 13, the Beijing Municipal Government started soliciting public opinions for a draft plan designed to relieve the city's traffic problems.

  7. Evaluation of collagen/heparin coated TCP/HA granules for long-term delivery of BMP-2.

    Science.gov (United States)

    Hannink, Gerjon; Geutjes, Paul J; Daamen, Willeke F; Buma, Pieter

    2013-02-01

    Bone morphogenetic proteins (BMPs) are the most potent osteoinductive growth factors. However, a delivery system is essential to take advantage of the osteoinductive effect of BMPs. The purpose of this study was to develop a sustained delivery system for recombinant human bone morphogenetic protein-2 (BMP-2). We covalently attached heparin to a cross-linked collagen type I coated tricalciumphosphate/hydroxyapatite (TCP/HA) bone substitute and subsequently loaded it with BMP-2. To systematically evaluate the contribution of each component with respect to the binding and release of BMP-2, six constructs were prepared and characterized: TCP/HA, TCP/HA with collagen (TCP/HACol), and TCP/HA with collagen and heparin (TCP/HAColHep) with and without BMP-2 (B). More BMP-2 bound to the TCP/HAColHep + B (92.9 ± 4.8 ng BMP-2/mg granule) granules as compared to the TCP/HACol + B (69.0 ± 9.6 ng BMP-2/mg granule) and TCP/HA + B granules (62.9 ± 5.4 ng BMP-2/mg granule). No difference in release pattern was found between the TCP/HA + B and TCP/HACol + B granules. Up to day 14, BMP-2 was still bound to the TCP/HAColHep + B granules, whereas most BMP had been released from TCP/HACol + B and TCP/HA + B granules at that time. After 21 days most BMP-2 also had been released from the TCP/HAColHep + B granules. The local and sustained delivery system for BMP-2 developed in this study may be useful as a carrier for BMP-2 and could possibly enhance bone regeneration efficacy for the treatment of large bone defects.

  8. Allegheny County Traffic Counts

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Traffic sensors at over 1,200 locations in Allegheny County collect vehicle counts for the Pennsylvania Department of Transportation. Data included in the Health...

  9. Ethernet traffic measurement

    OpenAIRE

    Santschi, Yann; Corthay, François

    2012-01-01

    The goal of this project is to create a FPGA Ethernet traffic measurement point and interface it with an existing measurement network, named DPMI, that is developed in Blekinge Institute of Technology.

  10. Non-Traffic Citations

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Non-traffic citations (NTCs, also known as "summary offenses") document low-level criminal offenses where a law enforcement officer or other authorized official...

  11. "Christian carrying goomies".

    Science.gov (United States)

    1994-01-01

    Dr. Passingan Usurup tells critics of his pragmatic approach on condom promotion that he is a Christian carrying condoms for Christ. He is head of the University of Papua New Guinea Medical Center and is credited with developing an AIDS/HIV policy for the Papua New Guinea Defence Force. The condoms were named Goomy and promoted at launching in 1992 in a blue packet under the slogan "The bond that guards." Goomy was chosen as the name because it is pidgin for rubber, chewing gum, and anything associated with rubber. Blue packets were chosen over the calls of most soldiers for a camouflage design because of its universal appeal as the color of the sea and sky and because it was the preference of women in the airlines. Once firmly ensconced in his role at the University, Usurup plans to develop a policy for students and staff and help to conduct AIDS prevention and education activities on campus. He will encourage students to test for HIV rather than highlighting the gloom and doom of infection and disease.

  12. Light-weight TCP/IP stack based on wireless embedded system%基于无线嵌入式系统的轻量级TCP/IP协议栈

    Institute of Scientific and Technical Information of China (English)

    吕俊龙; 陈春燕; 和卫星

    2010-01-01

    提出了一种基于小型无线嵌入式系统的轻量级TCP/IP协议栈CW_TCP/IP(compact wireless-TCP/IP).CW-TCP/IP使用适于小型嵌入式系统的简单数据结构调用CCB(connection control block)来处理TCP/IP,它创建TCP/IP头文件时不需参考其它数据结构,可以采用TCP Veno拥塞控制算法来提高其无线性能.该协议栈具有很高的便携性,因此可开发为处理器和独立的操作系统,目前它可以移植到Linux系统.通过实验对适用于小型嵌入式操作系统的CW-TCP/IP、Linux TCP/IP和μC/TCP-IP的性能进行了比较,比较的结果表明了CW-TCP/IP具有卓越的无线性能.

  13. 基于TCP Vegas拥塞控制算法的研究与改进%Improvement and Research on Congestion Control Algorithm of TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    谢怡宁; 孙广路; 苏洁; 翟继强

    2011-01-01

    网络拥塞已经成为制约因特网发展的瓶颈.在众多TCP拥塞控制算法中,TCP Vegas表现出比其他算法更为优越的性能,但是在特定环境下也存在不足.本文通过对网络拥塞策略的研究和Vegas性能的分析,验证了Vegas整体性能优于Reno的结论,并通过分析Vegas的特点,针对α和β的值对公平性的影响,提出了一种在TCP Vegas与TCP Reno共存环境下获得良好拥塞控制的方法,并通过网络仿真证明了本方法的有效性和正确性.%Network congestion has become a bottleneck restricting the development of the Internet. Among the TCP congestion control algorithm,TCP Vegas shows more than the other algorithms superior performance. However, in certain circumstances there are disadvantages. Based on the strategy of network congestion and Vegas performance analysis, validation of the overall performance is better than Reno' s conclusion. By analyzing the characteristics of Vegas for the a and β value on the fairness of this paper, a TCP Vegas and TCP Reno for good co-existence environment,congestion control,and network simulation proves the validity and accuracy of this method.

  14. Fair and Efficient TCP Access in the IEEE 802.11 Infrastructure Basic Service Set

    CERN Document Server

    Keceli, Feyza; Ayanoglu, Ender

    2008-01-01

    When the stations in an IEEE 802.11 infrastructure Basic Service Set (BSS) employ Transmission Control Protocol (TCP) in the transport layer, this exacerbates per-flow unfair access which is a direct result of uplink/downlink bandwidth asymmetry in the BSS. We propose a novel and simple analytical model to approximately calculate the per-flow TCP congestion window limit that provides fair and efficient TCP access in a heterogeneous wired-wireless scenario. The proposed analysis is unique in that it considers the effects of varying number of uplink and downlink TCP flows, differing Round Trip Times (RTTs) among TCP connections, and the use of delayed TCP Acknowledgment (ACK) mechanism. Motivated by the findings of this analysis, we design a link layer access control block to be employed only at the Access Point (AP) in order to resolve the unfair access problem. The novel and simple idea of the proposed link layer access control block is employing a congestion control and filtering algorithm on TCP ACK packets...

  15. Osteogenesis Capacity of a Novel BMP/α-TCP Bioactive Composite Bone Cement

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-zhong; ZHOU Da-li; YIN Shao-ya; YIN Guang-fu; GAO Li-da; ZHANG Yun

    2004-01-01

    To improve the osteogenesis ability of α-tricalcium phosphate (α-TCP) bone cement,a novel BMP/α-TCP composite bone cement was prepared.By measuring the setting time and compressive strength,the hydration characteristic of bone cement was evaluated.Animal experiments including histological observation,radiographic investigation as well as digital image analyses reveal the difference of osteogenesis ability among BMP,α-TCP bone cement and BMP/α-TCP composite bone cement.Results show that α-TCP bone cement possesses excellent hydration and setting properties as well as high mechanical property.Comparison experiments show that BMP/α-TCP composite bone cement has a stronger osteogenesis ability.The gross observation of the implant site does not exhibit any inflammation or necrosis.Histological analyses reveal that the material has good osteointegration with host bone,and new bone formation is detected within the materials,which are degrading.Strong osteogenesis ability of the composite is due to not only the excellent osteoconductive potential but also the osteoinductive potential contributed by active BMP releasing and the material degradation.Large skull defect could be well-healed by filling BMP/α-TCP composite bone cement.This novel material proves itself to be an absorbable and bioactive bone cement with an osteogenesis ability.

  16. Improving TCP Throughput Using Modified Packet Reordering Technique (MPRT Over Manets

    Directory of Open Access Journals (Sweden)

    Prakash B. Khelage

    2014-08-01

    Full Text Available at the beginning of development of network technology TCP transport agent were designed assuming that communication is using wired network, but recently there is huge demand and use of wireless networks for communication. Those TCP variants which are successful in wired networks are neither able to detect exact causes of packet losses nor unnecessary transmission delays over wireless networks. The biggest challenge over MANET is design of robust and reliable TCP variant which should give best performance in different network scenarios. Till date more than dozens of TCP variants designed and modified by researcher and scientist communities even though the level of TCP performance have to be optimum in different scenarios, Such as congestion, link failure, signal loss and interferences. Over rod, grid and bulk network model also. As some of TCP-variant performs well in particular network scenarios but degrades in other scenarios. The objective of this research work, to modify packet reordering technique based TCP variant, implement and compare its performance with other variants. Validation of basic and main network model done using network simulator (NS2 and calculated throughput, delay and packet drop by processing trace files. The simulated result shows that, proposed technique performs outstanding almost in all network scenarios with minimum packet losses and minimum delay.

  17. TCP with header checksum option for wireless links: An analytical approach towards performance evaluation

    Indian Academy of Sciences (India)

    Pawan Kumar Gupta; Joy Kuri

    2007-06-01

    TCP performs poorly in wireless mobile networks due to large bit error rates. Basically, the TCP sender responds to these losses as if they were due to congestion in the network, and reduces the congestion window unnecessarily. In earlier work, it has been shown that adding a TCP header checksum is very useful in differentiating between congestion loss and corruption loss. With the modified TCP, receivers can explicitly indicate corruption of received packets by generating “Explicit Loss Notifications (ELNs).” This paper focuses on an analytical study of this modified TCP protocol. We derive an expression for the probability of a receiver generating successful ELN, assuming a generic link layer protocol for data transfer over wireless links. Next, we develop an analytical approach for TCP throughput evaluation under the modified scheme. We compare the throughput results obtained by analysis and simulation, and find very close agreement between the two sets. We also compare the performance of the modified scheme with the standard NewReno TCP, and find considerable improvement in data throughput over wireless links.

  18. Poly (γ-glutamic acid)/beta-TCP nanocomposites via in situ copolymerization: Preparation and characterization.

    Science.gov (United States)

    Shu, Xiu-Lin; Shi, Qing-Shan; Feng, Jin; Yang, Yun-Hua; Zhou, Gang; Li, Wen-Ru

    2016-07-01

    A series biodegradable poly (γ-glutamic acid)/beta-tricalcium phosphate (γ-PGA/TCP) nanocomposites were prepared which were composed of poly-γ-glutamic acid polymerized in situ with β-tricalcium phosphate and physiochemically characterized as bone graft substitutes. The particle size via dynamic light scattering, the direct morphological characterization via transmission electron microscopy and field emission scanning electron microscope, which showed that γ-PGA and β-TCP were combined compactly at 80℃, and the γ-PGA/TCP nanocomposites had homogenous and nano-sized grains with narrow particle size distributions. The water uptake and retention abilities, in vitro degradation properties, cytotoxicity in the simulated medium, and protein release of these novel γ-PGA/TCP composites were investigated. Cell proliferation in composites was nearly twice than β-TCP when checked in vitro using MC3T3 cell line. We also envision the potential use of γ-PGA/TCP systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering applications. These observations suggest that the γ-PGA/TCP are novel nanocomposites with great potential for application in the field of bone tissue engineering.

  19. Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area.

    Science.gov (United States)

    Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

    2016-01-01

    Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications.

  20. Magnesium incorporation into β-TCP reduced its in vivo resorption by decreasing parathormone production.

    Science.gov (United States)

    Yassuda, Debora H; Costa, Neusa F M; Fernandes, Gustavo O; Alves, Gutemberg G; Granjeiro, José M; Soares, Glória de A

    2013-07-01

    Beta-tricalcium phosphate (β-TCP), one of the most widely used bioresorbable materials for bone therapy, can be doped with magnesium ions, generating β-TCMP. The objectives of this work were to evaluate, on a murine dental alveolus grafting model, the biocompatibility of β-TCP and β-TMCP granules by histomorphometric analysis, as well as the impact on plasmatic levels of receptor activator of nuclear factor κB ligand (RANK-L), osteoprotegerin (OPG), osteocalcin, osteopontin, and parathormone (PTH) during bone repair, using Luminex multiplexing technology. After grafting for 42 days, β-TCP grafted group presented higher bioresorption and induced more newly formed bone than β-TCMP (p TCP grafting also induced higher plasmatic levels of RANK-L, compared to β-TCMP and control (blood clot) groups at 21st day (p TCP by the 42nd day (p TCP group and attained a peak on the 21st day. In conclusion, β-TCP granules were more bioresorbable and osteogenic than β-TCMP granules, and the resorption of both materials might have been affected by osteoclastogenesis modulated by changes in the plasmatic levels of PTH and RANK-L.

  1. Comparative phylogenomic analysis provides insights into TCP gene functions in Sorghum.

    Science.gov (United States)

    Francis, Aleena; Dhaka, Namrata; Bakshi, Mohit; Jung, Ki-Hong; Sharma, Manoj K; Sharma, Rita

    2016-12-05

    Sorghum is a highly efficient C4 crop with potential to mitigate challenges associated with food, feed and fuel. TCP proteins are of particular interest for crop improvement programs due to their well-demonstrated roles in crop domestication and shaping plant architecture thereby, affecting agronomic traits. We identified 20 TCP genes from Sorghum. Except SbTCP8, all are either intronless or contain introns in the untranslated regions. Comparative phylogenetic analysis of Arabidopsis, rice, Brachypodium and Sorghum TCP proteins revealed two distinct classes categorized into ten sub-clades. Sub-clade F is dicot-specific, whereas A2, G1 and I1 groups only contained genes from grasses. Sub-clade B was missing in Sorghum, whereas group A1 was missing in rice indicating species-specific divergence of TCP proteins. TCP proteins of Sorghum are enriched in disorder promoting residues with class I containing higher percent disorder than class II proteins. Seven pairs of paralogous TCP genes were identified from Sorghum, five of which seem to predate Rice-Sorghum divergence. All of them have diverged in their expression. Based on the expression and orthology analysis, five Sorghum genes have been shortlisted for further investigation for their roles in regulating plant morphology. Whereas, three genes have been identified as candidates for engineering abiotic stress tolerance.

  2. Models of TCP in high-BDP environments and their experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vardoyan, G. [University of Massachusetts; Rao, Nageswara S [ORNL; Towlsey, D. [University of Massachusetts

    2016-01-01

    In recent years, the computer networking community has seen a steady growth in bandwidth-delay products (BDPs). Several TCP variants were created to combat the shortcomings of legacy TCP when it comes to operation in high-BDP environments. These variants, among which are CUBIC, STCP, and H-TCP, have been extensively studied in some empirical contexts, and some analytical models exist for CUBIC and STCP. However, since these studies have been conducted, BDPs have risen even more, and new bulk data transfer tools have emerged that utilize multiple parallel TCP streams. In view of these new developments, it is imperative to revisit the question: Which congestion control algorithms are best adapted to current networking environments? In order to help resolve this question, we contribute the following: (i) using first principles, we develop a general throughput-prediction framework that takes into account buffer sizes and maximum window constraints; (ii) we validate the models using measurements and achieve low prediction errors; (iii) we note differences in TCP dynamics between two experimental configurations and find one of them to be significantly more deterministic than the other; we also find that CUBIC and H-TCP outperform STCP, especially when multiple streams are used; and (iv) we present preliminary results for modelling multiple TCP streams for CUBIC and STCP.

  3. Genomewide analysis of TCP transcription factor gene family in Malus domestica

    Indian Academy of Sciences (India)

    Ruirui Xu; Peng Sun; Fengjuan Jia; Longtao Lu; Yuanyuan Li; Shizhong Zhang; Jinguang Huang

    2014-12-01

    Teosinte branched1/cycloidea/proliferating cell factor1 (TCP) proteins are a large family of transcriptional regulators in angiosperms. They are involved in various biological processes, including development and plant metabolism pathways. In this study, a total of 52 TCP genes were identified in apple (Malus domestica) genome. Bioinformatic methods were employed to predicate and analyse their relevant gene classification, gene structure, chromosome location, sequence alignment and conserved domains of MdTCP proteins. Expression analysis from microarray data showed that the expression levels of 28 and 51 MdTCP genes changed during the ripening and rootstock–scion interaction processes, respectively. The expression patterns of 12 selected MdTCP genes were analysed in different tissues and in response to abiotic stresses. All of the selected genes were detected in at least one of the tissues tested, and most of them were modulated by adverse treatments indicating that the MdTCPs were involved in various developmental and physiological processes. To the best of our knowledge, this is the first study of a genomewide analysis of apple TCP gene family. These results provide valuable information for studies on functions of the TCP transcription factor genes in apple.

  4. Matching references with MEDLINE via TCP/IP.

    Science.gov (United States)

    Guidi, J N

    1993-01-01

    Bibliographic references are an important part of databases and information resources used by clinicians and biomedical researchers. In addition to the obvious clerical advantages of standard references, bibliographic references can also be used as links to related items in different data sets. This paper describes an effort that involved matching references from a variety of disparate databases to canonical MEDLINE references. The references matched were those involved in a database unification project which is part of the Mouse Genome Informatics effort at The Jackson Laboratory. Software was developed to take advantage of a commercially available retrieval engine which accesses MEDLINE on CD-ROM disks. The software permits client programs on UNIX/C, and potentially other environments, to access unabridged MEDLINE via networks supporting the TCP/IP protocols. The matching process described can be used as a model for similar efforts with different research or clinical data sets, as well as different hardware or software environments.

  5. Bone engineering by phosphorylated-pullulan and β-TCP composite.

    Science.gov (United States)

    Takahata, Tomohiro; Okihara, Takumi; Yoshida, Yasuhiro; Yoshihara, Kumiko; Shiozaki, Yasuyuki; Yoshida, Aki; Yamane, Kentaro; Watanabe, Noriyuki; Yoshimura, Masahide; Nakamura, Mariko; Irie, Masao; Van Meerbeek, Bart; Tanaka, Masato; Ozaki, Toshifumi; Matsukawa, Akihiro

    2015-11-20

    A multifunctional biomaterial with the capacity bond to hard tissues, such as bones and teeth, is a real need for medical and dental applications in tissue engineering and regenerative medicine. Recently, we created phosphorylated-pullulan (PPL), capable of binding to hydroxyapatite in bones and teeth. In the present study, we employed PPL as a novel biocompatible material for bone engineering. First, an in vitro evaluation of the mechanical properties of PPL demonstrated both PPL and PPL/β-TCP composites have higher shear bond strength than materials in current clinical use, including polymethylmethacrylate (PMMA) cement and α-tricalcium phosphate (TCP) cement, Biopex-R. Further, the compressive strength of PPL/β-TCP composite was significantly higher than Biopex-R. Next, in vivo osteoconductivity of PPL/β-TCP composite was investigated in a murine intramedular injection model. Bone formation was observed 5 weeks after injection of PPL/β-TCP composite, which was even more evident at 8 weeks; whereas, no bone formation was detected after injection of PPL alone. We then applied PPL/β-TCP composite to a rabbit ulnar bone defect model and observed bone formation comparable to that induced by Biopex-R. Implantation of PPL/β-TCP composite induced new bone formation at 4 weeks, which was remarkably evident at 8 weeks. In contrast, Biopex-R remained isolated from the surrounding bone at 8 weeks. In a pig vertebral bone defect model, defects treated with PPL/β-TCP composite were almost completely replaced by new bone; whereas, PPL alone failed to induce bone formation. Collectively, our results suggest PPL/β-TCP composite may be useful for bone engineering.

  6. The enzyme toxicity and genotoxicity of chlorpyrifos and its toxic metabolite TCP to zebrafish Danio rerio.

    Science.gov (United States)

    Wang, Jun; Wang, Jinhua; Zhu, Lusheng; Xie, Hui; Shao, Bo; Hou, Xinxin

    2014-12-01

    Chlorpyrifos is a broad-spectrum organophosphorus insecticide (O,O-diethyl -O-3,5,6-trichloro-2-pyridyl phosphorothioate) that is used in numerous agricultural and urban pest controls. The primary metabolite of chlorpyrifos is 3,5,6-trichloro pyridine-2-phenol (TCP). Because of its strong water solubility and mobility, this harmful metabolite exists in the environment in a large amount. Although TCP has potentially harmful effects on organisms in the environment, few studies have addressed TCP pollution. Therefore, this study was undertaken to investigate the effect of chlorpyrifos and TCP on the microsomal cytochrome P450 content in the liver, on the activity of NADPH-P450 reductase and antioxidative enzymes [catalase (CAT) and superoxide dismutase (SOD)], and on reactive oxygen species (ROS) generation and DNA damage in zebrafish. Male and female zebrafish were separated and exposed to a control solution and three concentrations of chlorpyrifos (0.01, 0.1, 1 mg L(-1)) and TCP (0.01, 0.1, 0.5 mg L(-1)), respectively, sampled after 5, 10, 15, 20 and 25 days. The results indicated that the P450 content and the NADPH-P450 reductase and antioxidative enzyme (CAT and SOD) activities could be induced by chlorpyrifos and TCP. DNA damage of zebrafish was enhanced with increasing chlorpyrifos and TCP concentrations. Meanwhile, chlorpyrifos and TCP induced a significant increase of ROS generation in the zebrafish hepatopancreas. In conclusion, this study proved that chlorpyrifos (0.01-1 mg L(-1)) and TCP (0.01-0.5 mg L(-1)) are both highly toxic to zebrafish.

  7. TCP-friendliness Analysis and Evaluation for TCP-like IVS Flow Control Algorithm%TCP-like IVS流量控制算法TCP友好性的模拟评价和分析

    Institute of Scientific and Technical Information of China (English)

    贺凯健; 林亚平

    2002-01-01

    TCP-like IVS流量控制算法是对IVS流量控制算法的改进,提高了数据流稳定性和减小数据流抖动.文章研究TCP-like ⅣS流与TCP流争抢带宽资源中的TCP友好性问题.通过理论分析和模拟实验指出TCP-1ikeIVS流TCP友好性差的原因,提出未来改进的方向,为深入研究英特网上视频会议系统的QoS保证打下基础.

  8. Occupant traffic estimation through structural vibration sensing

    Science.gov (United States)

    Pan, Shijia; Mirshekari, Mostafa; Zhang, Pei; Noh, Hae Young

    2016-04-01

    The number of people passing through different indoor areas is useful in various smart structure applications, including occupancy-based building energy/space management, marketing research, security, etc. Existing approaches to estimate occupant traffic include vision-, sound-, and radio-based (mobile) sensing methods, which have placement limitations (e.g., requirement of line-of-sight, quiet environment, carrying a device all the time). Such limitations make these direct sensing approaches difficult to deploy and maintain. An indirect approach using geophones to measure floor vibration induced by footsteps can be utilized. However, the main challenge lies in distinguishing multiple simultaneous walkers by developing features that can effectively represent the number of mixed signals and characterize the selected features under different traffic conditions. This paper presents a method to monitor multiple persons. Once the vibration signals are obtained, features are extracted to describe the overlapping vibration signals induced by multiple footsteps, which are used for occupancy traffic estimation. In particular, we focus on analysis of the efficiency and limitations of the four selected key features when used for estimating various traffic conditions. We characterize these features with signals collected from controlled impulse load tests as well as from multiple people walking through a real-world sensing area. In our experiments, the system achieves the mean estimation error of +/-0.2 people for different occupant traffic conditions (from one to four) using k-nearest neighbor classifier.

  9. TCP/IP协议在计算机网络中的应用

    Institute of Scientific and Technical Information of China (English)

    付登刚

    2016-01-01

    网络发展的基础就是TCP/IP协议,属于网络协议的一种类型,目前,我们日常生活中使用的计算机协议,TCP/IP协议可以实现计算机的网络互连,但是,安全漏洞在TCP/IP协议中也是广泛存在的,本文主要针对TCP/IP协议的应用及其安全漏洞进行分析.

  10. Si-TCP Synthesized from "Mg-free" Reagents Employed as Calcium Phosphate Cement

    OpenAIRE

    Mariana Motisuke; Raul García Carrodeguas; Cecília Amélia Carvalho Zavaglia

    2012-01-01

    The influence of silicon doping on calcium phosphate cement were explored in this work. α-TCP and Si-α-TCP were prepared by solid state reaction employing "Mg-free" CaHPO4, CaCO3 and CaSiO3 as precursors. It was possible to obtain TCP powders with low contents of β phase as contaminant. Cement liquid phase was an aqueous solution containing 2.5 wt. (%) of Na2HPO4 and 1.5 wt. (%) of citric acid. The liquid-to-powder ratio was 0.6 mL.g-1. Chemical, physical and mechanical propert...

  11. A New Route for Preparation of β-TCP/PLLA Composite

    Institute of Scientific and Technical Information of China (English)

    Feng ZHANG; Fang MEI; Xin Zhi WANG; Xiao Yang HU; Yong Ming LUO; Xu Liang DENG

    2006-01-01

    A new facile route for preparation of β-TCP/PLLA composites is reported in this letter.SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse.Two months later histological examination showed that new collagen and new dentin formed.The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation, offering a new way to dental tissue engineering.

  12. Air traffic management evaluation tool

    Science.gov (United States)

    Sridhar, Banavar (Inventor); Sheth, Kapil S. (Inventor); Chatterji, Gano Broto (Inventor); Bilimoria, Karl D. (Inventor); Grabbe, Shon (Inventor); Schipper, John F. (Inventor)

    2012-01-01

    Methods for evaluating and implementing air traffic management tools and approaches for managing and avoiding an air traffic incident before the incident occurs. A first system receives parameters for flight plan configurations (e.g., initial fuel carried, flight route, flight route segments followed, flight altitude for a given flight route segment, aircraft velocity for each flight route segment, flight route ascent rate, flight route descent route, flight departure site, flight departure time, flight arrival time, flight destination site and/or alternate flight destination site), flight plan schedule, expected weather along each flight route segment, aircraft specifics, airspace (altitude) bounds for each flight route segment, navigational aids available. The invention provides flight plan routing and direct routing or wind optimal routing, using great circle navigation and spherical Earth geometry. The invention provides for aircraft dynamics effects, such as wind effects at each altitude, altitude changes, airspeed changes and aircraft turns to provide predictions of aircraft trajectory (and, optionally, aircraft fuel use). A second system provides several aviation applications using the first system. Several classes of potential incidents are analyzed and averted, by appropriate change en route of one or more parameters in the flight plan configuration, as provided by a conflict detection and resolution module and/or traffic flow management modules. These applications include conflict detection and resolution, miles-in trail or minutes-in-trail aircraft separation, flight arrival management, flight re-routing, weather prediction and analysis and interpolation of weather variables based upon sparse measurements. The invention combines these features to provide an aircraft monitoring system and an aircraft user system that interact and negotiate changes with each other.

  13. Structural and Catalytic Differences between Two FADH2-Dependent Monooxygenases: 2,4,5-TCP 4-Monooxygenase (TftD from Burkholderia cepacia AC1100 and 2,4,6-TCP 4-Monooxygenase (TcpA from Cupriavidus necator JMP134

    Directory of Open Access Journals (Sweden)

    ChulHee Kang

    2012-08-01

    Full Text Available 2,4,5-TCP 4-monooxygenase (TftD and 2,4,6-TCP 4-monooxygenase (TcpA have been discovered in the biodegradation of 2,4,5-trichlorophenol (2,4,5-TCP and 2,4,6-trichlorophenol (2,4,6-TCP. TcpA and TftD belong to the reduced flavin adenine dinucleotide (FADH2-dependent monooxygenases and both use 2,4,6-TCP as a substrate; however, the two enzymes produce different end products. TftD catalyzes a typical monooxygenase reaction, while TcpA catalyzes a typical monooxygenase reaction followed by a hydrolytic dechlorination. We have previously reported the 3D structure of TftD and confirmed the catalytic residue, His289. Here we have determined the crystal structure of TcpA and investigated the apparent differences in specificity and catalysis between these two closely related monooxygenases through structural comparison. Our computational docking results suggest that Ala293 in TcpA (Ile292 in TftD is possibly responsible for the differences in substrate specificity between the two monooxygenases. We have also identified that Arg101 in TcpA could provide inductive effects/charge stabilization during hydrolytic dechlorination. The collective information provides a fundamental understanding of the catalytic reaction mechanism and the parameters for substrate specificity. The information may provide guidance for designing bioremediation strategies for polychlorophenols, a major group of environmental pollutants.

  14. Structural and catalytic differences between two FADH(2)-dependent monooxygenases: 2,4,5-TCP 4-monooxygenase (TftD) from Burkholderia cepacia AC1100 and 2,4,6-TCP 4-monooxygenase (TcpA) from Cupriavidus necator JMP134.

    Science.gov (United States)

    Hayes, Robert P; Webb, Brian N; Subramanian, Arun Kumar; Nissen, Mark; Popchock, Andrew; Xun, Luying; Kang, Chulhee

    2012-01-01

    2,4,5-TCP 4-monooxygenase (TftD) and 2,4,6-TCP 4-monooxygenase (TcpA) have been discovered in the biodegradation of 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,6-trichlorophenol (2,4,6-TCP). TcpA and TftD belong to the reduced flavin adenine dinucleotide (FADH(2))-dependent monooxygenases and both use 2,4,6-TCP as a substrate; however, the two enzymes produce different end products. TftD catalyzes a typical monooxygenase reaction, while TcpA catalyzes a typical monooxygenase reaction followed by a hydrolytic dechlorination. We have previously reported the 3D structure of TftD and confirmed the catalytic residue, His289. Here we have determined the crystal structure of TcpA and investigated the apparent differences in specificity and catalysis between these two closely related monooxygenases through structural comparison. Our computational docking results suggest that Ala293 in TcpA (Ile292 in TftD) is possibly responsible for the differences in substrate specificity between the two monooxygenases. We have also identified that Arg101 in TcpA could provide inductive effects/charge stabilization during hydrolytic dechlorination. The collective information provides a fundamental understanding of the catalytic reaction mechanism and the parameters for substrate specificity. The information may provide guidance for designing bioremediation strategies for polychlorophenols, a major group of environmental pollutants.

  15. Evaluation of the biotissue of PCL and {beta}-TCP; Avaliacao de um biotecido de PCL e {beta}-TCP

    Energy Technology Data Exchange (ETDEWEB)

    Solomao, Zenaide; Zavaglia, Cecilia A.C., E-mail: zavagl@fem.unicamp.br [Universidade Estadual de Campinas (DEMa/FEM/LABIOMEC/INCT), Campinas, SP (Brazil). Biofabris; Dias, Carmen G.B.T. [Universidade Federal do Para - FEM/ITEC-UFPA, Belem, PA (Brazil)

    2011-07-01

    The use of biomaterials to replace, repair injured tissues and organs of human beings has increased due to population growth and its higher life expectancy. The tissue engineering is an interdisciplinary field that integrates principles of biology, chemistry, genetics, materials science and biomedical engineering, to produce composite three-dimensional, capable of replacing biological tissues. The development of new biomaterials using the method of evaporation of the solvent can help to solvent this problem. This work aimed to characterized the membranes of poly ({epsilon}-caprolactone) dense and porous (scaffolds) of PCL/B-TCP; and make an in vitro evaluation. Techniques were used to: SEM, EDS, XRD, TGA, DSC, mechanical traction tests, test cell viability and activity of alkaline phosphatase (ALP). The hydrolytic degradation was analyzed in phosphate buffer (PBS) and the biocompatibility through standards (ASTM and ABNT) concluding that the materials are biocompatible and are used with great potential for replacement of the bone tissue. (author)

  16. Efficient IP Traffic over Optical Network Based on Wavelength Translation Switching

    DEFF Research Database (Denmark)

    Jha, Vikas; Kalia, Kartik; Chowdhary, Bhawani Shankar

    2016-01-01

    With the advent of TCP/IP protocol suite the overall era of communication technologies had been redefined. Now, we can’t ignore the presence of huge amount of IP traffic; data, voice or video increasing day by day creating more pressure on existing communicating media and supporting back bone...... cross connects based on translation of wavelength when an IP packet is crossing the optical cross connect. Adding the concepts of layer 3 routing protocols along with the wavelength translation scheme, will help in spanning the overall optical network for a larger area....

  17. Research and Development of Industrial Real-time TCP/IP Protocol Stack%工业实时TCP/IP协议栈的研究与开发

    Institute of Scientific and Technical Information of China (English)

    韦安; 刘国平

    2005-01-01

    指出了通用TCP/IP协议用于工业控制存在的不足,通过对标准TCP/IP协议栈的简化,并加入自行开发的协议,开发了NETCON-TCP工业以太网控制协议,较好地解决了TCP/IP应用于实际控制中所存在的主要问题,详细描述了协议栈开发的细节.最后对比了NETCON-TCP和LINUX-TCP的实时性,验证了NETCON-TCP协议具有实时性好、体积小、可靠性较高的优点.

  18. Research TCP/IP Network Communication Programming on Java Socket%JAVA TCP/IP Socket网络通信编程研究

    Institute of Scientific and Technical Information of China (English)

    戴歆

    2013-01-01

    First Java is a programming language for Internet. network Communication is the advantage of Java language. Using TCP/IP communication protocol in the program development is to realize the C/S model of point to point communication net-work. This thesis focuses on the study of Java Socket network programming framework and network communication program implementation in C/S mode.%Java最初是一种网络编程语言网络通信是Java语言的优势,在程序开发中利用TCP/IP通信协议则能实现C/S模式下的点对点的网络通信。该文主要研究在C/S模式下使用Java Socket实现TCP/IP网络程序框架及网络通信的程序实现。

  19. Comparative study of microstructural remodification to porous β-TCP and HA in rabbits

    Institute of Scientific and Technical Information of China (English)

    SUN Jiao; SHEN QingYi; LU JianXi

    2009-01-01

    emodeling pattern resulted from bone formation and scaffold resorption was significantly different for the two bioceramics.The results demonstrated that the 75% porous β-TCP was more suitable for new bone remodification than HA scaffold.

  20. An adaptive mechanism to guarantee the bandwidth fairness of TCP flows

    Institute of Scientific and Technical Information of China (English)

    张顺亮; 叶澄清

    2004-01-01

    End-to-end TCP(transmission control protocol)congestion control can cause unfairness among multiple TCP connections with different RTT(Round Trip Time). The throughput of TCP connection is inversely proportional to its RTT.To resolve this problem,researchers have proposed many methods. The existing proposals for RTT-aware conditioner work well when congestion level is low. However,they over-protect long RTT flows and starve short RTT flows when congestion level is high. Due to this reason,an improved method based on adaptive thought is proposed. According to the congestion level of networks,the mechanism can adaptively adjust the degree of the protection to long RTT flows. Extensive simulation experiments showed that the proposed mechanism can guarantee the bandwidth fairness of TCP flows effectively and outperforms the existing methods.

  1. An adaptive mechanism to guarantee the bandwidth fairness of TCP flows

    Institute of Scientific and Technical Information of China (English)

    张顺亮; 叶澄清

    2004-01-01

    End-to-end TCP (transmission control protocol) congestion control can cause unfairness among multiple TCP connections with different RTT (Round Trip Time). The throughput of TCP connection is inversely proportional to its RTT. To resolve this problem, researchers have proposed many methods. The existing proposals for RTT-aware conditioner work well when congestion level is low. However, they over-protect long RTT flows and starve short RTT flows when congestion level is high. Due to this reason, an improved method based on adaptive thought is proposed. According to the congestion level of networks, the mechanism can adaptively adjust the degree of the protection to long RTT flows. Extensive simulation experiments showed that the proposed mechanism can guarantee the bandwidth fairness of TCP flows effectively and outperforms the existing methods.

  2. SM_TCP: a new reliable multicast transport protocol for satellite IP networks

    Science.gov (United States)

    Liu, Gongliang; Gu, Xuemai; Li, Shizhong

    2005-11-01

    A new reliable multicast transport protocol SM_TCP is proposed for satellite IP networks in this paper. In SM_TCP, the XOR scheme with the aid of on-board buffering and processing is used for error recovery and an optimal retransmission algorithm is designed, which can reduce the recovery time by half of the RTT and minimize the number of retransmissions. In order to avoid the unnecessary decrease of congestion window in the high BER satellite channels, the occupied buffer sizes at bottlenecks are measured in adjusting the congestion window, instead of depending on the packet loss information. The average session rate of TCP sessions and of multicast sessions passing through the satellite are also measured and compared in adjusting the congestion window, which contributes to bandwidth fairness. Analysis and simulation results show fairness with TCP flows and scalability.

  3. 关于TCP/IP协议分析和应用研究

    Institute of Scientific and Technical Information of China (English)

    万焱

    2015-01-01

    作为大国与最大发展中国家的在新时期担负着建设现代化TCP/IP协议和社会主义新中国的伟大责任,应当借助生物技术、信息技术等高新技术的有效支持,注重加速发展。TCP/IP协议面临着不少的分析问题。为此,本文阐述了TCP/IP协议分析,以及解决TCP/IP协议面临分析的应用研究。

  4. Comparative Performance Evaluation of TCP Variants in WiMAX (and WLANs Network Configurations

    Directory of Open Access Journals (Sweden)

    Konstantinos Tsiknas

    2012-01-01

    Full Text Available An important application for the IEEE 802.16 technology (also called WiMAX is to provide high-speed access to the Internet where the transmission control protocol (TCP is the core transport protocol. In this paper we study through extensive simulation scenarios the performance characteristics of five representative TCP schemes, namely, TCP New Reno, Vegas, Veno, Westwood, and BIC, in WiMAX (and WLANs networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities, and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control and suggest the best schemes to be employed in WiMAX networks.

  5. TCP/IP网络通信协议的实现与探讨

    Institute of Scientific and Technical Information of China (English)

    张凯

    2008-01-01

    TCP/IP协议(Transmissiorl Control Protocol/Internet Protocol)是目前最成功的网络通信协议,它被用于当今所构筑的最大的开放式网络系统Internet之上就是其成功的证明.TCP/IP协议具有广泛的兼容性和可伸缩性,可连接不同的计算机网络协议、不同的网络设备.TCP/IP事实上己成为网络互联的标准,并成为支持Internet/Intranet的协议标淮.本文就是针对当前流行的TCP/IP网络通信协议的实现进行了具体的研究和探讨.

  6. Si-TCP synthesized from "Mg-free" reagents employed as calcium phosphate cement

    Directory of Open Access Journals (Sweden)

    Mariana Motisuke

    2012-08-01

    Full Text Available The influence of silicon doping on calcium phosphate cement were explored in this work. α-TCP and Si-α-TCP were prepared by solid state reaction employing "Mg-free" CaHPO4, CaCO3 and CaSiO3 as precursors. It was possible to obtain TCP powders with low contents of β phase as contaminant. Cement liquid phase was an aqueous solution containing 2.5 wt. (% of Na2HPO4 and 1.5 wt. (% of citric acid. The liquid-to-powder ratio was 0.6 mL.g-1. Chemical, physical and mechanical properties of the cement samples were determined by means of XRD, FTIR, XRF, compressive strength and SEM. The calcium phosphate cements obtained achieved satisfactory properties; however, Si-α-TCP presented a decrease on the rate of setting reaction.

  7. Synthesis of bioactive β-TCP coatings with tailored physico-chemical properties on zirconia bioceramics.

    Science.gov (United States)

    Stefanic, Martin; Milacic, Radmila; Drazic, Goran; Škarabot, Miha; Budič, Bojan; Krnel, Kristoffer; Kosmač, Tomaž

    2014-10-01

    The objective of this work was to develop a synthesis procedure for the deposition of β-TCP coatings with tailored physico-chemical properties on zirconia bioceramics. The synthesis procedure involved two steps: (i) a rapid wet-chemical deposition of a biomimetic CaP coating and (ii) a subsequent post-deposition processing of the biomimetic CaP coating, which included a heat treatment between 800 and 1200 °C, followed by a short sonication in a water bath. By regulating the heating temperature the topography of the β-TCP coatings could be controlled. The average surface roughness (Ra) ranged from 42 nm for the coating that was heated at 900 °C (TCP-900) to 630 nm for the TCP-1200 coating. Moreover, the heating temperature also affected the dissolution rate of the coatings in a physiological solution, their protein-adsorption capacity and their bioactivity in a simulated body fluid.

  8. TCP performance evaluation over AODV and DSDV in RW and SN mobility models

    Institute of Scientific and Technical Information of China (English)

    REN Wei; YEUNG D.Y.; JIN Hai

    2006-01-01

    This paper presents evaluation and comparison of the TCP performance in different mobile scenarios generated by Random Waypoint (RW) and Social Network (SN) mobility models. To our knowledge, TCP performance in SN mobility is discussed for the first time. The impact of AODV and DSDV routing protocols on the TCP goodput, delay and drop rate performance is also discussed. Extensive simulation results and analysis showed that TCP has better performance over AODV than over DSDV and has more stable performance in SN mobility than in RW mobility. We suggest using more mobility models, in particular, such as SN, in the evaluations of the transport layer or routing layer protocols because the mobility patterns have impacts on the protocol performance.

  9. 基于PSO-SVM的Modbus TCP通讯的异常检测方法%Modbus/TCP Communication Anomaly Detection Algorithm Based on PSO-SVM

    Institute of Scientific and Technical Information of China (English)

    尚文利; 张盛山; 万明; 曾鹏

    2014-01-01

    To detect and defend industry virus attacks to application layer protocol data is difficult issues in study of industrial security gateway .In this paper ,a data pre-processing method is presented ,which can convert Modbus TCP traffic into anomaly de-tection model ,and a PSO-SVM algorithm is designed ,which optimizes parameters by advanced Particle Swarm Optimization (PSO) algorithm .The method identifies anomalies of Modbus TCP traffic according to appear frequencies of the mode short sequence of Modbus function code sequence .Finally ,experimental data analysis shows that the proposed method can effectively detect abnormal of Modbus function code sequence .%如何有效检测和防御工业病毒对应用层协议数据的攻击是目前工业安全网关研究的难点问题。本文提出了将Modbus TCP通讯流量转换为异常检测模型所需数据形式的预处理方法,设计了一种利用粒子群PSO算法进行参数寻优的PSO-SVM算法。该方法根据Modbus功能码序列中的模式短序列出现的频率,识别出异常的Modbus TCP通讯流量。最后,通过实验数据分析,说明了提出方法可以有效实现对Modbus功能码序列的异常检测。

  10. DYNAMIC PCU VALUES AT SIGNALISED INTERSECTIONS IN INDIA FOR MIXED TRAFFIC

    Directory of Open Access Journals (Sweden)

    Sheela Alex

    2015-06-01

    Full Text Available The traffic stream behaves differently in a mixed traffic condition as compared to that of a homogeneous condition. In a mixed traffic condition, as the traffic behaviour is always fluctuating based on the interaction caused by the surrounding elements, it is essential that the factors which affect the dynamic nature of the traffic characteristics should be considered for the proper design of the system. The paper highlights the methodology for developing the dynamic Passenger Car Unit (PCU under various vehicular interactions for mixed traffic conditions prevalent in India. Experiments were carried out using the micro simulation model, TRAFFICSIM, which was developed for signalised intersections by the authors and reported elsewhere. The dynamic PCU values were obtained based on the analysis of the outputs of TRAFFICSIM, for varying approach width, traffic composition, stream speed and traffic volume. Modified area occupancy concept was used to develop Dynamic PCU values in a mixed traffic condition. In the modified area occupancy method, the area occupancy of the vehicle types for various traffic compositions is compared with area occupancy of the passenger cars in a car only traffic condition having the same stream speed. The study showed that the PCU values are highly sensitive to the given traffic conditions such as approach width, traffic composition, stream speed as well as flow ratio.

  11. Occurrence in Mexico, 1998-2008, of Vibrio cholerae CTX+ El Tor carrying an additional truncated CTX prophage.

    Science.gov (United States)

    Alam, Munirul; Rashed, Shah Manzur; Mannan, Shahnewaj Bin; Islam, Tarequl; Lizarraga-Partida, Marcial Leonardo; Delgado, Gabriela; Morales-Espinosa, Rosario; Mendez, Jose Luis; Navarro, Armando; Watanabe, Haruo; Ohnishi, Makoto; Hasan, Nur A; Huq, Anwar; Sack, R Bradley; Colwell, Rita R; Cravioto, Alejandro

    2014-07-08

    The seventh cholera pandemic caused by Vibrio cholerae O1 El Tor (ET) has been superseded in Asia and Africa by altered ET possessing the cholera toxin (CTX) gene of classical (CL) biotype. The CL biotype of V. cholerae was isolated, along with prototypic and altered ET, during the 1991 cholera epidemic in Mexico and subsequently remained endemic until 1997. Microbiological, molecular, and phylogenetic analyses of clinical and environmental V. cholerae isolated in Mexico between 1998 and 2008 revealed important genetic events favoring predominance of ET over CL and altered ET. V. cholerae altered ET was predominant after 1991 but not after 2000. V. cholerae strains isolated between 2001 and 2003 and a majority isolated in 2004 lacked CTX prophage (Φ) genes encoding CTX subunits A and B and repeat sequence transcriptional regulators of ET and CL biotypes: i.e., CTXΦ(-). Most CTXΦ(-) V. cholerae isolated in Mexico between 2001 and 2003 also lacked toxin coregulated pili tcpA whereas some carried either tcpA(ET) or a variant tcpA with noticeable sequence dissimilarity from tcpA(CL). The tcpA variants were not detected in 2005 after CTXΦ(+) ET became dominant. All clinical and environmental V. cholerae O1 strains isolated during 2005-2008 in Mexico were CTXΦ(+) ET, carrying an additional truncated CTXΦ instead of RS1 satellite phage. Despite V. cholerae CTXΦ(-) ET exhibiting heterogeneity in pulsed-field gel electrophoresis patterns, CTXΦ(+) ET isolated during 2004-2008 displayed homogeneity and clonal relationship with V. cholerae ET N16961 and V. cholerae ET isolated in Peru.

  12. The Predigest Project of TCP/IP Protocol Communication System Based on DSP Technology and Ethernet

    Science.gov (United States)

    hong-you, Wang; san-ping, Zhao

    The paper introduce a predigest project of TCP/IP based on DSP CMOS chip TMS320F2407 and Ethernet interface. The system design the Network Interface Controller using TMS320F2407and TRL8019AS,it simplify TCP/IP, achieve simple protocol stack in DSP, and achieve Data transmission by software program. The experiment indicated that, the communication system constructed by TMS320F2407andTRL8019AS is low cast, simple and reliable.

  13. Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing.

    Science.gov (United States)

    Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

    2015-01-06

    The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer-ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds' critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering.

  14. Fermi-LAT detection of the Galactic nova TCP J18102829-2729590

    Science.gov (United States)

    Li, Kwan-Lok; Chomiuk, Laura

    2016-11-01

    Fermi-LAT detection of the Galactic nova TCP J18102829-2729590 Following the discovery of the nova in Sagittarius TCP J18102829-2729590 (CBAT 2016 10 20.383; ATel #9658), we triggered an one-week Fermi ToO (observation number: 090603-1-1; PI: Laura Chomiuk) from 2016-10-25 as part of our Fermi-LAT monitoring campaign for Galactic novae (ATel #9311).

  15. Biofabrication of a PLGA-TCP-based porous bioactive bone substitute with sustained release of icaritin.

    Science.gov (United States)

    Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Leng, Yang; Tang, Ting-Ting; Pan, Xiaohua; Qin, Ling

    2015-08-01

    A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l-lactide-co-glycolide)-tricalcium phosphate (PLGA-TCP)-based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin-releasing PLGA-TCP-based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro-computed tomography (micro-CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA-TCP scaffold was quantified by high-performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA-TCP-icaritin composite scaffold was porous, with interconnected macro- (about 480 µm) and micropores (2-15 µm). The mechanical properties of the PLGA-TCP-icaritin scaffold were comparable with those of the pure PLGA-TCP scaffold, yet was spinning direction-dependent. Icaritin content was detected in the medium and increased with time. The PLGA-TCP-icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA-TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic

  16. Osteointegration of PLGA implants with nanostructured or microsized β-TCP particles in a minipig model.

    Science.gov (United States)

    Kulkova, Julia; Moritz, Niko; Suokas, Esa O; Strandberg, Niko; Leino, Kari A; Laitio, Timo T; Aro, Hannu T

    2014-12-01

    Bioresorbable suture anchors and interference screws have certain benefits over equivalent titanium-alloy implants. However, there is a need for compositional improvement of currently used bioresorbable implants. We hypothesized that implants made of poly(l-lactide-co-glycolide) (PLGA) compounded with nanostructured particles of beta-tricalcium phosphate (β-TCP) would induce stronger osteointegration than implants made of PLGA compounded with microsized β-TCP particles. The experimental nanostructured self-reinforced PLGA (85L:15G)/β-TCP composite was made by high-energy ball-milling. Self-reinforced microsized PLGA (95L:5G)/β-TCP composite was prepared by melt-compounding. The composites were characterized by gas chromatography, Ubbelohde viscometry, scanning electron microscopy, laser diffractometry, and standard mechanical tests. Four groups of implants were prepared for the controlled laboratory study employing a minipig animal model. Implants in the first two groups were prepared from nanostructured and microsized PLGA/β-TCP composites respectively. Microroughened titanium-alloy (Ti6Al4V) implants served as positive intra-animal control, and pure PLGA implants as negative control. Cone-shaped implants were inserted in a random order unilaterally in the anterior cortex of the femoral shaft. Eight weeks after surgery, the mechanical strength of osteointegration of the implants was measured by a push-out test. The quality of new bone surrounding the implant was assessed by microcomputed tomography and histology. Implants made of nanostructured PLGA/β-TCP composite did not show improved mechanical osteointegration compared with the implants made of microsized PLGA/β-TCP composite. In the intra-animal comparison, the push-out force of two PLGA/β-TCP composites was 35-60% of that obtained with Ti6Al4V implants. The implant materials did not result in distinct differences in quality of new bone surrounding the implant.

  17. Traffic Light Detection

    DEFF Research Database (Denmark)

    Philipsen, Mark Philip; Jensen, Morten Bornø; Møgelmose, Andreas

    2015-01-01

    Traffic light recognition (TLR) is an integral part of any intelligent vehicle, which must function in the existing infrastructure. Pedestrian and sign detection have recently seen great improvements due to the introduction of learning based detectors using integral channel features. A similar push...... database is collected based on footage from US roads. The database consists of both test and training data, totaling 46,418 frames and 112,971 annotated traffic lights, captured in continuous sequences under a varying light and weather conditions. The learning based detector achieves an AUC of 0.4 and 0...

  18. Generalized Deterministic Traffic Rules

    CERN Document Server

    Fuks, H; Fuks, Henryk; Boccara, Nino

    1997-01-01

    We study a family of deterministic models for highway traffic flow which generalize cellular automaton rule 184. This family is parametrized by the speed limit $m$ and another parameter $k$ that represents a ``degree of aggressiveness'' in driving, strictly related to the distance between two consecutive cars. We compare two driving strategies with identical maximum throughput: ``conservative'' driving with high speed limit and ``aggressive'' driving with low speed limit. Those two strategies are evaluated in terms of accident probability. We also discuss fundamental diagrams of generalized traffic rules and examine limitations of maximum achievable throughput. Possible modifications of the model are considered.

  19. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus

    Science.gov (United States)

    Harn, Tony; Spielman, Ingrid; Gao, Yang; Kovacikova, Gabriela; Biais, Nicolas

    2016-01-01

    Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. PMID:27992883

  20. Application of the Embedded TCP/IP Protocol by DSP%嵌入式TCP/IP协议栈在DSP上的实现

    Institute of Scientific and Technical Information of China (English)

    倪秀胜

    2006-01-01

    介绍了TMS320C5402芯片与RTL8019AS互联网控制器的硬件接口电路的设计,实现了一个运行在TMS320C5402上的小型嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议、ICMP协议进行分析,完成了基于TCP/IP协议的嵌入式网络系统.

  1. ATM QoS Experiments Using TCP Applications: Performance of TCP/IP Over ATM in a Variety of Errored Links

    Science.gov (United States)

    Frantz, Brian D.; Ivancic, William D.

    2001-01-01

    Asynchronous Transfer Mode (ATM) Quality of Service (QoS) experiments using the Transmission Control Protocol/Internet Protocol (TCP/IP) were performed for various link delays. The link delay was set to emulate a Wide Area Network (WAN) and a Satellite Link. The purpose of these experiments was to evaluate the ATM QoS requirements for applications that utilize advance TCP/IP protocols implemented with large windows and Selective ACKnowledgements (SACK). The effects of cell error, cell loss, and random bit errors on throughput were reported. The detailed test plan and test results are presented herein.

  2. Improve performance of tcp new reno over mobile ad-hoc network using abra

    CERN Document Server

    Bisen, Dhananjay

    2011-01-01

    In a mobile ad hoc network, temporary link failures and route changes occur frequently. With the assumption that all packet losses are due to congestion, TCP performs poorly in such an environment. There are many versions of TCP which modified time to time as per need. In this paper modifications introduced on TCP New Reno over mobile ad-hoc networks using calculation of New Retransmission Time out (RTO), to improve performance in term of congestion control. To calculate New RTO, adaptive backoff response approach (ABRA) in TCP New Reno was applied which suggest ABRA New Reno. It utilizes an ABRA by which congestion window and slow start threshold values were decreased whenever an acknowledgement is received and new backoff value calculate from smoothed round trip time. Evaluation based on comparative study of ABRA New Reno with other TCP Variants like New Reno and Reno was done using realistic parameters like TCP Packet Received, Packet Drop, Packets Retransmitted, Throughput, and Packet Delivery Ratio calcu...

  3. Performance of TCP Vegas, Bic and Reno Congestion Control Algorithms on Iridium Satellite Constellations

    Directory of Open Access Journals (Sweden)

    M.Nirmala

    2012-11-01

    Full Text Available Satellite networking is different from wired or wireless networks. The behavior and the performance of TCP/IP in normal wireless network as well as in wired network are different from one another. The TCP/IP protocol was not designed to perform well over high-latency or noisy channels so its performance over satellite networks are totally different. Each satellite networks/constellations have different properties. The deployment height, motion, direction, link capacity – all differ from one satellite constellations to another. So, certainly the behavior of TCP/IP will considerably differ from one satellite constellations than another.The Performance of three different TCP Congestion algorithms, Vegas, Reno and Bic are taken for evaluation on the simulated satellite network Iridium and the performance of the three algorithms under the satellites constellation is measured using suitable metrics. It is observed that, irrespective of the high end to end delay, the behavior of TCP/IP under Satellite network is somewhat resembling a high latency wired network. TCP under satellite network is not like that of a mobile ADHOC network. The observation resulted that the overall performance of Vegas was good in Iridium constellations. These reasons should be explored for designing a better congestion control algorithm exclusively for Satellite Networks.

  4. TCP: a tool for designing chimera proteins based on the tertiary structure information

    Directory of Open Access Journals (Sweden)

    Nishida Reina

    2009-01-01

    Full Text Available Abstract Background Chimera proteins are widely used for the analysis of the protein-protein interaction region. One of the major issues is the epitope analysis of the monoclonal antibody. In the analysis, a continuous portion of an antigen is sequentially substituted into a different sequence. This method works well for an antibody recognizing a linear epitope, but not for that recognizing a discontinuous epitope. Although the designing the chimera proteins based on the tertiary structure information is required in such situations, there is no appropriate tool so far. Results In light of the problem, we developed a tool named TCP (standing for a Tool for designing Chimera Proteins, which extracts some sets of mutually orthogonal cutting surfaces for designing chimera proteins using a genetic algorithm. TCP can also incorporate and consider the solvent accessible surface area information calculated by a DSSP program. The test results of our method indicate that the TCP is robust and applicable to various shapes of proteins. Conclusion We developed TCP, a tool for designing chimera proteins based on the tertiary structure information. TCP is robust and possesses several favourable features, and we believe it is a useful tool for designing chimera proteins. TCP is freely available as an additional file of this manuscript for academic and non-profit organization.

  5. Congestion Control in TCP/AQM Networks Using a Disturbance Observer

    Science.gov (United States)

    Kubo, Ryogo; Kani, Junichi; Fujimoto, Yukihiro

    This paper presents a novel congestion controller for transmission control protocol/active queue management (TCP/AQM) networks. In order to maintain the queue length to a value less than the buffer size at the aggregation nodes, the queue management mechanism drops some packets depending on the probability calculated by a congestion controller. However, conventional controllers such as random early detection (RED) algorithms and proportional-integral-derivative (PID)-based controllers are not compatible with parameter variation in TCP/AQM networks. Parameter variation in TCP/AQM networks includes the change of the number of TCP connections, the inflow of user datagram protocol (UDP) flows and so on. In the proposed method, the effect of parameter variation is estimated as drop probability disturbance by using a disturbance observer (DOB). By using the DOB, disturbance suppression characteristics of the controlled system can be drastically improved. In addition, the TCP/AQM network system is analyzed on the basis of an acceleration control scheme. The proposed method is validated by simulation studies performed using a nonlinear model of a TCP/AQM network and verifications made using the network simulator ns-2.

  6. Improve Performance of TCP New Reno Over Mobile Ad-Hoc Network Using ABRA

    Directory of Open Access Journals (Sweden)

    Dhananjay Bisen

    2011-05-01

    Full Text Available In a mobile ad hoc network, temporary link failures and route changes occur frequently. With theassumption that all packet losses are due to congestion, TCP performs poorly in such an environment.There are many versions of TCP which modified time to time as per need. In this paper modificationsintroduced on TCP New Reno over mobile ad-hoc networks using calculation of New RetransmissionTime out (RTO, to improve performance in term of congestion control. To calculate New RTO, adaptivebackoff response approach (ABRA in TCP New Reno was applied which suggest ABRA New Reno. Itutilizes an ABRA by which congestion window and slow start threshold values were decreased wheneveran acknowledgement is received and new backoff value calculate from smoothed round trip time.Evaluation based on comparative study of ABRA New Reno with other TCP Variants like New Reno andReno was done using realistic parameters like TCP Packet Received, Packet Drop, Packets Retransmitted,Throughput, and Packet Delivery Ratio calculated by varying attributes of Node Speed, Number of Nodesand Pause Time. Implementation and simulations were performed in QualNet 4.0 simulator.

  7. Development of bioactive porous α-TCP/HAp beads for bone tissue engineering.

    Science.gov (United States)

    Asaoka, Teruo; Ohtake, Shoji; Furukawa, Katsuko S; Tamura, Akito; Ushida, Takashi

    2013-11-01

    Porous beads of bioactive ceramics such as hydroxyapatite (HAp) and tribasic calcium phosphate (TCP) are considered a promising scaffold for cultivating bone cells. To realize this, α-TCP/HAp functionally graded porous beads are fabricated with two main purposes: to maintain the function of the scaffold with sufficient strength up to the growth of new bone, and is absorbed completely after the growth. HAp is a bioactive material that has both high strength and strong tissue-adhesive properties, but is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable, resulting in a scaffold that is absorbed before it is completely replaced by bone. In this study, we produced porous, bead-shaped carriers as scaffolds for osteoblast culture. To control the solubility in vivo, the fabricated beads contained α-TCP at the center and HAp at the surface. Cell adaptability of these beads for bone tissue engineering was confirmed in vitro. It was found that α-TCP/HAp bead carriers exhibit low toxicity in the initial stages of cell seeding and cell adhesion. The presence of HAp in the composite bead form effectively increased ALP activity. In conclusion, it is suggested that these newly developed α-TCP/HAp beads are a promising tool for bone tissue engineering.

  8. Analysis of the TCP genes expressed in the inflorescence of the orchid Orchis italica.

    Science.gov (United States)

    De Paolo, Sofia; Gaudio, Luciano; Aceto, Serena

    2015-11-04

    TCP proteins are plant-specific transcription factors involved in many different processes. Because of their involvement in a large number of developmental pathways, their roles have been investigated in various plant species. However, there are almost no studies of this transcription factor family in orchids. Based on the available transcriptome of the inflorescence of the orchid Orchis italica, in the present study we identified 12 transcripts encoding TCP proteins. The phylogenetic analysis showed that they belong to different TCP classes (I and II) and groups (PCF, CIN and CYC/TB1), and that they display a number of conserved motifs when compared with the TCPs of Arabidopsis and Oryza. The presence of a specific cleavage site for the microRNA miRNA319, an important post-transcriptional regulator of several TCP genes in other species, was demonstrated for one transcript of O. italica, and the analysis of the expression pattern of the TCP transcripts in different inflorescence organs and in leaf tissue suggests that some TCP transcripts of O. italica exert their role only in specific tissues, while others may play multiple roles in different tissues. In addition, the evolutionary analysis showed a general purifying selection acting on the coding region of these transcripts.

  9. Biological optimization of simultaneous boost on intra-prostatic lesions (DILs): sensitivity to TCP parameters.

    Science.gov (United States)

    Azzeroni, R; Maggio, A; Fiorino, C; Mangili, P; Cozzarini, C; De Cobelli, F; Di Muzio, N G; Calandrino, R

    2013-11-01

    The aim of this investigation was to explore the potential of biological optimization in the case of simultaneous integrated boost on intra-prostatic dominant lesions (DIL) and evaluating the impact of TCP parameters uncertainty. Different combination of TCP parameters (TD50 and γ50 in the Poisson-like model), were considered for DILs and the prostate outside DILs (CTV) for 7 intermediate/high-risk prostate patients. The aim was to maximize TCP while constraining NTCPs below 5% for all organs at risk. TCP values were highly depending on the parameters used and ranged between 38.4% and 99.9%; the optimized median physical doses were in the range 94-116 Gy and 69-77 Gy for DIL and CTV respectively. TCP values were correlated with the overlap PTV-rectum and the minimum distance between rectum and DIL. In conclusion, biological optimization for selective dose escalation is feasible and suggests prescribed dose around 90-120 Gy to the DILs. The obtained result is critically depending on the assumptions concerning the higher radioresistence in the DILs. In case of very resistant clonogens into the DIL, it may be difficult to maximize TCP to acceptable levels without violating NTCP constraints.

  10. The effect of Tricresyl-Phosphate (TCP) as an additive on wear of Iron (Fe)

    Science.gov (United States)

    Ghose, Hiren M.; Ferrante, John; Honecy, Frank C.

    1987-01-01

    The effect of tricresyl phosphate (TCP) as an antiwear additive in lubricant trimethyol propane triheptanoate (TMPTH) was investigated. The objective was to examine step loading wear by use of surface analysis, wetting, and chemical bonding changes in the lubricant. The investigation consisted of steploading wear studies by a pin or disk tribometer, the effects on wear related to wetting by contact angle and surface tension measurements of various liquid systems, the chemical bonding changes between lubricant and TCP chromatographic analysis, and by determining the reaction between the TCP and metal surfaces through wear scar analysis by Auger emission spectroscopy (AES). The steploading curve for the base fluid alone shows rapid increase of wear rate with load. The steploading curve for the base fluid in presence of 4.25 percent by volume TCP under dry air purge has shown a great reduction of wear rate with all loads studied. It has also been found that the addition of 4.25 percent by volume TCP plus 0.33 percent by volume water to the base lubricant under N2 purge also greatly reduces the wear rate with all loads studied. AES surface analysis reveals a phosphate type wear resistant film, which greatly increases load-bearing capacity, formed on the iron disk. Preliminary chromatographic studies suggest that this film forms either because of ester oxidation or TCP degradation. Wetting studies show direct correlation between the spreading coefficient and the wear rate.

  11. A cellular automaton model for ship traffic flow in waterways

    Science.gov (United States)

    Qi, Le; Zheng, Zhongyi; Gang, Longhui

    2017-04-01

    With the development of marine traffic, waterways become congested and more complicated traffic phenomena in ship traffic flow are observed. It is important and necessary to build a ship traffic flow model based on cellular automata (CAs) to study the phenomena and improve marine transportation efficiency and safety. Spatial discretization rules for waterways and update rules for ship movement are two important issues that are very different from vehicle traffic. To solve these issues, a CA model for ship traffic flow, called a spatial-logical mapping (SLM) model, is presented. In this model, the spatial discretization rules are improved by adding a mapping rule. And the dynamic ship domain model is considered in the update rules to describe ships' interaction more exactly. Take the ship traffic flow in the Singapore Strait for example, some simulations were carried out and compared. The simulations show that the SLM model could avoid ship pseudo lane-change efficiently, which is caused by traditional spatial discretization rules. The ship velocity change in the SLM model is consistent with the measured data. At finally, from the fundamental diagram, the relationship between traffic ability and the lengths of ships is explored. The number of ships in the waterway declines when the proportion of large ships increases.

  12. Membrane Traffic Within the Golgi Apparatus

    OpenAIRE

    Glick, Benjamin S; Nakano, Akihiko

    2009-01-01

    Newly synthesized secretory cargo molecules pass through the Golgi apparatus while resident Golgi proteins remain in the organelle. However, the pathways of membrane traffic within the Golgi are still uncertain. Most of the available data can be accommodated by the cisternal maturation model, which postulates that Golgi cisternae form de novo, carry the secretory cargoes forward, and ultimately disappear. The entry face of the Golgi receives material that has been exported from transitional E...

  13. 2013 Traffic Safety Culture Index

    Science.gov (United States)

    ... death in the United States. 2013 Traffic Safety Culture Index January 2014 607 14th Street, NW, Suite ... org | 202-638-5944 Title 2013 Traffic Safety Culture Index (January 2014) About the Sponsor AAA Foundation ...

  14. New Conclusion of RTT Fairness Analysis on TCP Congestion Control%传输控制协议拥塞控制中往返时间公平性分析的新结论

    Institute of Scientific and Technical Information of China (English)

    姜文刚; 孙金生; 王执铨

    2011-01-01

    通过平面图形和建模的方法,分析了传输控制协议(TCP)拥塞控制中的网络往返时间(RTT)公平性.对于瓶颈链路,如果采用主动队列管理(AQM),两个竞争的TCP数据流流量比值近似为RTT比的倒数,存在RTT不公平性;如果采用弃尾队列管理,只有在不发生数据包超时的情况下,才出现明显的RTT不公平性,如果出现数据包发送超时,则情况较为复杂,频繁出现RTT大的TCP数据流多占用网络带宽的现象,因此很难得到一般性的结论.最后通过NS2仿真来验证所建模型和分析方法的正确性.%RTT (round-trip time) fairness in TCP (transmission control protocol) congestion control is analyzed by means of flat graphics and modeling. For the bottleneck link, if using active queue management (AQM), the flow ratio of the two competing TCP traffic streams is approximately the inverse of the RTT ratio, then the RTT unfairness exists. Otherwise, if using drop tail queue management, the obvious RTT unfairness will appear only in the case that the data packets do not time out. If the sending of the packets times out, it will be more complex, that is, large TCP flows of RTT will occupy the network bandwidth, and it is difficult to get a general conclusion. Finally, the NS2 simulations indicate the correctness of the model and the analysis method.

  15. Urban Traffic Eco-Driving: Speed Advisory Tracking

    OpenAIRE

    De Nunzio, Giovanni; Canudas De Wit, Carlos; Moulin, Philippe

    2014-01-01

    International audience; The evaluation of the benefits of an Eco-Driving assistance system is carried out in the urban environment in presence of traffic lights. The traffic evolution is modeled macroscopically with the Urban Variable-Length Model in a variable speed limits framework. Under the assumption of equal boundary flows, the vehicles in a road section dispose themselves according to well defined equilibrium conditions which are dependent on the traveling speed in the free-flow part o...

  16. INFRASTRUCTURE FACILITIES FOR MONITORING AND INTELLECTUAL ROAD TRAFFIC MANAGEMENT

    Directory of Open Access Journals (Sweden)

    G. Belov

    2014-10-01

    Full Text Available Review of automatic management of road traffic technologies in major cities of Ukraine is carried out in the given article. Priority directions of studies are determined for producing modern and perspective technologies in the given area. The facilities for monitoring and intelligence management of the road traffic on the basis of the programmed logical controller, using the device of fuzzy logic are considered.

  17. Chaotic Control of Network Traffic

    Institute of Scientific and Technical Information of China (English)

    YANG Tan; CUI Yi-Dong; JIN Yue-Hui; CHENG Shi-Duan

    2009-01-01

    A method of chaotic control on network traffic is presented.By this method,the chaotic network traffic can be controlled to a pre-assigned equilibrium point according to chaotic prediction and the largest Lyapunov exponent of the traffic on congested link is reduced,thereby the probability of traffic burst and network congestion can be reduced.Numerical examples show that this method is effective.

  18. A Model for Detecting Tor Encrypted Traffic using Supervised Machine Learning

    Directory of Open Access Journals (Sweden)

    Alaeddin Almubayed

    2015-06-01

    Full Text Available Tor is the low-latency anonymity tool and one of the prevalent used open source anonymity tools for anonymizing TCP traffic on the Internet used by around 500,000 people every day. Tor protects user's privacy against surveillance and censorship by making it extremely difficult for an observer to correlate visited websites in the Internet with the real physical-world identity. Tor accomplished that by ensuring adequate protection of Tor traffic against traffic analysis and feature extraction techniques. Further, Tor ensures anti-website fingerprinting by implementing different defences like TLS encryption, padding, and packet relaying. However, in this paper, an analysis has been performed against Tor from a local observer in order to bypass Tor protections; the method consists of a feature extraction from a local network dataset. Analysis shows that it's still possible for a local observer to fingerprint top monitored sites on Alexa and Tor traffic can be classified amongst other HTTPS traffic in the network despite the use of Tor's protections. In the experiment, several supervised machine-learning algorithms have been employed. The attack assumes a local observer sitting on a local network fingerprinting top 100 sites on Alexa; results gave an improvement amongst previous results by achieving an accuracy of 99.64% and 0.01% false positive.

  19. The Classroom Traffic Jam

    Science.gov (United States)

    Edwards, Arthur W.

    1977-01-01

    The importance of energy conservation is developed in this simulation. Children draw an automobile and then are asked to drive it through the classroom roadways. When a traffic jam results, students offer ways to eliminate it. The importance of mass transportation and car pools is stressed by the teacher. (MA)

  20. Air Traffic Flow Management

    CERN Document Server

    Ganu, Hrishikesh V

    2008-01-01

    Air Traffic Flow Management is the regulation of air traffic in order to avoid exceeding airport or flight sector capacity in handling traffic, and to ensure that available capacity is used efficiently. We have tried to explore the logic behind the claims by Bertsimas et.al about integral solutions to the LP relaxation of the Traffic Flow Management Problem(TFMP). Polyhedral theory only indicates that the stronger TFMP formulation of Bertsimas et.al might lead to integral solutions in some cases. Our computations indicate that the encouraging results reported by Bertsimas et.al are not merely fortuitous or due to their specific data set. Indeed, we found that the TFMP had integral solutions even in case of artificial data sets generated to include severe conflicts in the flight schedules. In our limited tests with 4-5 scenarios, we obtained non-integral solutions only once. This is of significant practical importance because, the LP relaxation can be solved even on small machines with low memory and processor...

  1. A Survey of DDOS Attacks in TCP/IP Stack

    Directory of Open Access Journals (Sweden)

    P.C. Senthil Mahesh

    2014-08-01

    Full Text Available The aim of study is to discuss DDOS attack in TCP/IP layer. A Denial-of-Service (DoS or Distributed Denial-of-Service (DDoS attack is an attempt to make a device or network source not available to its designed customers. The purposes and objectives of a DoS attack may differ, it usually includes initiatives to momentarily or consistently disrupt or hold solutions of a variety linked with the Online. As explanation, DDoS (Distributed Denial of Service attack are sent by two or more individuals, or bots. DoS (Denial of Service attack are sent by one person or system. DoS attack typically focus on sites or solutions organized on high-profile web or web servers such as financial institutions, bank card payment gateways and even main name servers. This technique has now seen comprehensive use in certain activities, used by server owners, or dissatisfied opponents on activities. Progressively, DoS attack have also been used as a way of level of resistance.

  2. ITSA: Internet Traffic Statistics Archive

    NARCIS (Netherlands)

    Hoogesteger, Martijn; Oliveira Schmidt, de Ricardo; Pras, Aiko

    2016-01-01

    Motivated by the fact that comprehensive and long term Internet traffic measurements can be hard to obtain, we have proposed and developed the Internet Traffic Statistics Archive (ITSA). Since 2013, ITSA concentrates reports on high-level statistics of Internet traffic worldwide. Examples of statist

  3. Pedalcylists. Traffic Safety Facts, 2000.

    Science.gov (United States)

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    This document provides statistical information on traffic accidents involving U.S. bicyclists. Data include: (1) trends in pedalcyclist and total traffic fatalities, 1990-2000; (2) non-occupant traffic fatalities, 1990-2000; (3) pedalcyclists killed and injured, and fatality and injury rates, by age and sex, 2000; and (4) pedalcyclist traffic…

  4. Embedded TCP/IP Stack Implemetation on TMS320VC5402%在TMS320VC5402上实现的嵌入式TCP/IP协议栈

    Institute of Scientific and Technical Information of China (English)

    曲延滨; 冯立国; 苏健勇

    2004-01-01

    实现一个运行在16位数字信号处理器TMS320VC5402上的小型嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议进行分析,完成基于TCP/IP协议的嵌入式网络系统.

  5. Effects of Traffic Lights on CA Traffic Model

    Institute of Scientific and Technical Information of China (English)

    SuweiFENG; GuoqingGU

    1997-01-01

    Cellular automaton traffic models can include various factors in traffic system with simple regulations and the corresponding computations and simulations are rather convenient and effective.In this paper,the Biham-Middleton-Levine model(briefly saying the BML model)is improved by removing its limitation of synchronized change of traffic lights.In new model,the traffic light at each crossing could arbitrarily change its starting time and tempo of variation and hence the model could more realistically describe the influence of traffic lights on the performance of traffic systems.The cases of traffic light with unsynchronized starting time and different tempo of variation are simulated in this paper.

  6. TCP/IP网络协议栈攻击防范措施研究分析%TCP / IP Protocol Stack Attack Prevention Measures Study

    Institute of Scientific and Technical Information of China (English)

    曾振东

    2013-01-01

    由于TCP/IP网络协议栈在设计上的安全缺陷和脆弱性,使得在协议栈各个网络层次上均存在着各种类型的网络攻击技术方法,对互联网及内部网络的安全性造成威胁.该文主要介绍对网络各层的安全协议,也分别列举说明了各层的网络安全防范措施,对如何改善网络安全配置和使用条件,对TCP/IP网络协议栈攻击的防范技术及其发展,进行研究分析.%As the TCP/IP protocol stack in the design of security flaws and vulnerabilities in the protocol stack, so that each net?work level there are various types of network attack technology, on the Internet and the internal network security threat. This pa?per mainly introduces the network layer security protocol, were also examples of each layer of network security precautions, on how to improve the network security configuration and use conditions, the TCP/IP protocol stack attack prevention technology and its development, research and analysis.

  7. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA as a Candidate Subunit Cholera Vaccine

    Directory of Open Access Journals (Sweden)

    Neda Molaee

    2017-01-01

    Full Text Available Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response.

  8. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA) as a Candidate Subunit Cholera Vaccine.

    Science.gov (United States)

    Molaee, Neda; Mosayebi, Ghasem; Amozande-Nobaveh, Alireza; Soleyman, Mohammad Reza; Abtahi, Hamid

    2017-01-01

    Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response.

  9. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA) as a Candidate Subunit Cholera Vaccine

    Science.gov (United States)

    Molaee, Neda; Amozande-Nobaveh, Alireza; Soleyman, Mohammad Reza

    2017-01-01

    Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response. PMID:28191473

  10. Comparative histomorphometric analysis between α-Tcp cement and β-Tcp/Ha granules in the bone repair of rat calvaria

    Directory of Open Access Journals (Sweden)

    Gisela Grandi

    2011-03-01

    Full Text Available This study compared the effect of two bioceramics on the process of bone repair: α-tricalcium phosphate (α-TCP cement and β-tricalcium phosphate hydroxyapatite particles (β-TCP/HA. Calvarial defects were created in 50 rats, divided into two groups (α and β/HA. Software was used at 7, 21, 60, 90 and 120 days to assess bone formation. Mean new bone formation rates were as follows: α group, 1.6% at 7 days, 5.24% at 21 days, 24% at 60 days, 30.21% at 90 days and 50.59% at 120 days; β/HA group, 1.94% at 7 days, 2.53% at 21 days, 12.47% at 60 days, 26.84% at 90 days and 38.82% at 120 days; control group, 0.15% at 7 days, 10.12% at 21 days, 15.10% at 60 days, 18.94% at 90 days, 48.50% at 120 days. Both materials are osteoconductive and biocompatible. Perhaps the larger rate of new bone formation observed in the α-TCP group, it also occurs in the β-TCP/HA group within a longer time period.

  11. Network Programming tcp/ip protocol and socket discussion%网络编程tcp/ip协议与socket论述

    Institute of Scientific and Technical Information of China (English)

    严谦; 阳泳

    2016-01-01

    随着互联网技术的不断发展,网络通信成为当前互联网技术的重要技术,所以当前网络编程技术成为当前互联网通信发展的核心技术。网络编程主要是的通过使用套接字来实现进程间的编程,在Windows系统中的网络编程的套接字winscok,而在linux系统中最常见的套接字就是socket,本文就linux网络编程中的tcp、ip协议以及socket套接字问题进行详细的论述。%With the continuous development of Internet technology, network communications become an important technology of Internet technology, so the current network programming technology as the core technology of the current development of Internet communications. Network programming primarily achieved through the use of socket programming between processes in Windows system network programming socket winscok, while in linux system is the most common socket socket, paper linux Network Programming the tcp, ip protocol and socket socket issues are discussed in detail.

  12. On fast carry select adders

    Science.gov (United States)

    Shamanna, M.; Whitaker, S.

    1992-01-01

    This paper presents an architecture for a high-speed carry select adder with very long bit lengths utilizing a conflict-free bypass scheme. The proposed scheme has almost half the number of transistors and is faster than a conventional carry select adder. A comparative study is also made between the proposed adder and a Manchester carry chain adder which shows that the proposed scheme has the same transistor count, without suffering any performance degradation, compared to the Manchester carry chain adder.

  13. On fast carry select adders

    Science.gov (United States)

    Shamanna, M.; Whitaker, S.

    This paper presents an architecture for a high-speed carry select adder with very long bit lengths utilizing a conflict-free bypass scheme. The proposed scheme has almost half the number of transistors and is faster than a conventional carry select adder. A comparative study is also made between the proposed adder and a Manchester carry chain adder which shows that the proposed scheme has the same transistor count, without suffering any performance degradation, compared to the Manchester carry chain adder.

  14. Combining phylogenetic and syntenic analyses for understanding the evolution of TCP ECE genes in eudicots.

    Science.gov (United States)

    Citerne, Hélène L; Le Guilloux, Martine; Sannier, Julie; Nadot, Sophie; Damerval, Catherine

    2013-01-01

    TCP ECE genes encode transcription factors which have received much attention for their repeated recruitment in the control of floral symmetry in core eudicots, and more recently in monocots. Major duplications of TCP ECE genes have been described in core eudicots, but the evolutionary history of this gene family is unknown in basal eudicots. Reconstructing the phylogeny of ECE genes in basal eudicots will help set a framework for understanding the functional evolution of these genes. TCP ECE genes were sequenced in all major lineages of basal eudicots and Gunnera which belongs to the sister clade to all other core eudicots. We show that in these lineages they have a complex evolutionary history with repeated duplications. We estimate the timing of the two major duplications already identified in the core eudicots within a timeframe before the divergence of Gunnera and after the divergence of Proteales. We also use a synteny-based approach to examine the extent to which the expansion of TCP ECE genes in diverse eudicot lineages may be due to genome-wide duplications. The three major core-eudicot specific clades share a number of collinear genes, and their common evolutionary history may have originated at the γ event. Genomic comparisons in Arabidopsis thaliana and Solanumlycopersicum highlight their separate polyploid origin, with syntenic fragments with and without TCP ECE genes showing differential gene loss and genomic rearrangements. Comparison between recently available genomes from two basal eudicots Aquilegiacoerulea and Nelumbonucifera suggests that the two TCP ECE paralogs in these species are also derived from large-scale duplications. TCP ECE loci from basal eudicots share many features with the three main core eudicot loci, and allow us to infer the makeup of the ancestral eudicot locus.

  15. Engineering vascularized bone grafts by integrating a biomimetic periosteum and β-TCP scaffold.

    Science.gov (United States)

    Kang, Yunqing; Ren, Liling; Yang, Yunzhi

    2014-06-25

    Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration.

  16. β-TCP granules mixed with reticulated hyaluronic acid induce an increase in bone apposition.

    Science.gov (United States)

    Aguado, Eric; Pascaretti-Grizon, Florence; Gaudin-Audrain, Christine; Goyenvalle, Eric; Chappard, Daniel

    2014-02-01

    β beta-tricalcium phosphate (β-TCP) granules are suitable for repair of bone defects. They have an osteoconductive effect shortly after implantation. However, dry granules are difficult to handle in the surgical room because of low weight and lack of cohesion. Incorporation of granules in a hydrogel could be a satisfactory solution. We have investigated the use of hyaluronic acid (HyA) as an aqueous binder of the granules. β-TCP granules were prepared by the polyurethane foam technology. Commercially available linear (LHya) and reticulated hyaluronic acid (RHyA) in aqueous solution were used to prepare a pasty mixture that can be handled more easily than granules alone. Thirteen New Zealand White rabbits (3.5-3.75 kg) were used; a 4 mm hole was drilled in each femoral condyle. After flushing, holes were filled with either LHyA, RHyA, dry β-TCP granules alone, β-TCP granules + LHyA and β-TCP granules + RHyA. Rabbits were allowed to heal for one month, sacrificed and femurs were harvested and analysed by microCT and histomorphometry. The net amount of newly formed bone was derived from measurements done after thresholding the microCT images for the material and for the material+bone. LHyA and RHyA did not result in healing of the grafted area. LHyA was rapidly eluted from the grafted zone but allowed deposition of more granules, although the amount of formed bone was not significantly higher than with β-TCP granules alone. RHyA permitted the deposition of more granules which induced significantly more bone trabeculae without inducing an inflammatory reaction. RHyA appears to be a good vehicle to implant granules of β-TCP, since HyA does not interfere with bone remodeling.

  17. CNoA: Challenging Number Approach for uncovering TCP SYN flooding using SYN spoofing attack

    Directory of Open Access Journals (Sweden)

    L.Kavisankar

    2011-10-01

    Full Text Available The challenging number is used for the detection of Spoofing attack. The IP Spoofing is considered to beone of the potentially brutal attack which acts as a tool for the DDoS attack which is considered to be amajor threat among security problems in today’s internet. These kinds of attack are extremely severe.They bring down business of company drastically. DDoS attack can easily exhaust the computing andcommunication resources of its victim within a short period of time. There are attacks exploiting somevulnerability or implementation bug in the software implementation of a service to bring that down andsome attacks will use all the available resources at the target machine. This deals on attacks thatconsume all the bandwidth available to the victim machine. While concentrating on the bandwidth attackthe TCP SYN flood is the more prominent attack. TCP/IP protocol suite is the most widely used protocolsuite for data communication. The TCP SYN flood works by exhausting the TCP connection queue of thehost and thus denying legitimate connection request. There are various methods used to detect andprevent this attack, one of which is to block the packet based on SYN flag count from the same IP address.This kind of prevention methods becomes unsuitable when the attackers use the Spoofed IP address. TheSYN spoofing becomes a major tool the TCP SYN flooding. For the prevention of this kind of attacks, theTCP specific probing is used in the proposed scheme where the client is requested challenging numberwhile sending the ACK in the three way hand shake. This is very useful to find the Spoofed IPPackets/TCP SYN flood and preventing them.

  18. Traffic improvement and transportation pollution control in Xiamen

    Energy Technology Data Exchange (ETDEWEB)

    Dongxing Yuan; Zilin, Wu

    1996-12-31

    in this paper, the urban traffic improvement and transportation control in Xiamen are highlighted. Xiamen is a port city and an economical special zone of China. As the economy grows, the transportation is developing dramatically and becoming the key for further economic development. The air quality is threatened by the rapid growth of the vehicles in the city. The most urgent task in improving urban traffic is to establish a sound traffic system. The municipal government takes great effort to improve the traffic condition, as well as to reduce green house gases and protect air environment. Some management and technical measures are carried out. Those management measures are mainly as follows: (1) systematic planning of the city arrangement and city functional division, and integrated planning of the urban roads system, (2) putting great emphasis on tail gas monitoring and management, and (3) establishing optimized utilization of motor vehicles. Those included in the main technical measures are (1) making the roads clear, (2) enlarging traffic capacity, and (3) developing the public transport. The most urgent task in improving urban traffic is to establish a sound traffic system. The city municipal government and Transportation Management Bureau plan to make a series of reforms to improve the urban traffic condition, such as building high quality road around the city, reducing the number of one way roads and replacing gasoline buses with electric buses. An optimized traffic system of Xiamen, taking public transport as the main means, is the key to meet the needs of both traffic improvement and urban transportation pollution control.

  19. Virtualized Traffic at Metropolitan Scales

    Directory of Open Access Journals (Sweden)

    David eWilkie

    2015-05-01

    Full Text Available Few phenomena are more ubiquitous than traffic, and few are more significant economically, socially, or environmentally. Any virtual reality system, including virtual globes and immersive multi-player worlds that are set in a modern or futuristic setting feature traffic systems. Virtual reality models can also aid in addressing the challenges of real-world traffic systems, the ever-present gridlock and congestion in cities worldwide: traffic engineers and planners can diagnose system instabilities and explore control strategies in virtual worlds reconstructed from available sensor data. To create these systems, road network models need to be created and represented. Traffic needs to be realistically and efficiently simulated. To analyze real-world scenarios, the traffic conditions need to be estimated and reconstructed. To create virtual scenarios, such as simulated cities, traffic needs to be intelligently and efficiently routed.

  20. Modeling traffic on crossroads

    Science.gov (United States)

    Wastavino, L. A.; Toledo, B. A.; Rogan, J.; Zarama, R.; Muñoz, V.; Valdivia, J. A.

    2007-07-01

    A simplified traffic model is studied, consisting of two vehicles traveling through a sequence of crossroads regulated by yield signs. A car approaching a yield sign stops if, in the other street, there is a car closer than a certain distance xtol from the intersection. It is shown that the function which maps the state of the vehicles displays a period doubling transition to chaos. An interesting feature of the dynamics is that for extremely cautious drivers ( xtol too large), the map turns chaotic, thus becoming a potential source of emergent jams. Complex behavior such as the one observed in this simple system seems to be an essential ingredient in traffic patterns, and could be of relevance in studying actual crossroads situations.

  1. Road Traffic Noise

    Science.gov (United States)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  2. Dementia and Traffic Accidents

    DEFF Research Database (Denmark)

    Petersen, Jindong Ding; Siersma, Volkert; Nielsen, Connie Thurøe;

    2016-01-01

    BACKGROUND: As a consequence of a rapid growth of an ageing population, more people with dementia are expected on the roads. Little is known about whether these people are at increased risk of road traffic-related accidents. OBJECTIVE: Our study aims to investigate the risk of road traffic......-related accidents for people aged 65 years or older with a diagnosis of dementia in Denmark. METHODS: We will conduct a nationwide population-based cohort study consisting of Danish people aged 65 or older living in Denmark as of January 1, 2008. The cohort is followed for 7 years (2008-2014). Individual's personal...... data are available in Danish registers and can be linked using a unique personal identification number. A person is identified with dementia if the person meets at least one of the following criteria: (1) a diagnosis of the disease in the Danish National Patient Register or in the Danish Psychiatric...

  3. 基于TCP/IP协议的家电远程控制系统设计%Design of Remote Control System in Household Appliances Based on TCP/IP Protocol

    Institute of Scientific and Technical Information of China (English)

    李开国; 康志亮; 丁武伟; 沈茂

    2011-01-01

    A new remote control system based on STC89C58RD+ and ENC28J60 is designed. The system applies the simplified TCP/IP protocol to communicate IPv4 network with microcontroller, and the microcontroller can control multiple home appliances simultaneously by using infrared communication. The website can accept a lot of requests from multiple users. The network programs process the communication between the network and the corresponding microcontroller with aim of providing a remote control scheme, among which the multiuser can control multiple home appliances successfully. Experiments are carried out, and the results show that the rice cooker can be controlled remotely through internet.%利用STC89 C58 RD+单片机与ENC28J60网卡芯片设计了一种家电远程控制系统.该系统采用精简的TCP/IP协议实现单片机与IPv4网络通信,单片机用红外通信的方法来同时控制多个家电.网站接收多个用户请求,网络程序处理与对应单片机之间的通信,从而提供一种多用户远程控制多个家电的方案.对电饭煲进行测试,结果显示该方案能够通过互联网远程控制电饭煲.

  4. Untieing the Traffic Knot

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Beijing is working to resolve its longtime transportation problems before the 2008 Olympics One traffic jam after another, annoying horns, endless lines of cars,impatient sighs from passengers on an overcrowded bus, the youstomped-on-my-toe quarreling in the subway train, all have led to the unsurprising result that Beijing scored at the tail end of a survey of 287 cities in the category of transport satisfaction in China’s 2006 Report on the Quality of Urban Life.

  5. The Physics of Traffic

    Science.gov (United States)

    Davis, L. Craig

    2006-03-01

    Congestion in freeway traffic is an example of self-organization in the language of complexity theory. Nonequilibrium, first-order phase transitions from free flow cause complex spatiotemporal patterns. Two distinct phases of congestion are observed in empirical traffic data--wide moving jams and synchronous flow. Wide moving jams are characterized by stopped or slowly moving vehicles within the jammed region, which widens and moves upstream at 15-20 km/h. Above a critical density of vehicles, a sudden decrease in the velocity of a lead vehicle can initiate a transition from metastable states to this phase. Human behaviors, especially delayed reactions, are implicated in the formation of jams. The synchronous flow phase results from a bottleneck such as an on-ramp. Thus, in contrast to a jam, the downstream front is pinned at a fixed location. The name of the phase comes from the equilibration (or synchronization) of speed and flow rate across all lanes caused by frequent vehicle lane changes. Synchronous flow occurs when the mainline flow and the rate of merging from an on-ramp are sufficiently large. Large-scale simulations using car-following models reproduce the physical phenomena occurring in traffic and suggest methods to improve flow and mediate congestion.

  6. Effects of traffic noise

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, D.

    1986-02-01

    One of the main sources of noise is road traffic. In 1984 there were over 25 million cars, 1.2 million lorries, 1.3 million motor cycles and 1.6 million mopeds using our roads. Opinion polls showed that 21% of the population felt that they were affected by traffic noise as a nuisance factor. An outline of the effects of this noise on the affected population is given, illustrated by diagrams. Details about noise emissions (drive-past level) of the different types of vehicles in city traffic are stated and the effects of noise described. The author goes into the nuisance effect (noise is not a physical factor, but a psychosocial one), changes in behaviour (ways of speaking, reduction of stress on households in proportion to rising income and higher educational levels) and the consequences for health (the reaction of the body to noise is primarily a consequence of the psychosomatic organisation of ow bodies). In conclusion, the author deals with the subjective efficiency of noise protection measures. (HWJ).

  7. Assessing Road Traffic Expression

    Directory of Open Access Journals (Sweden)

    Fábio Silva

    2014-12-01

    Full Text Available Road traffic is a problem which is increasing in cities with large population. Unrelated to this fact the number of portable and wearable devices has also been increasing throughout the population of most countries. With this advent, the capacity to monitor and register data about people habits and locations as well as more complex data such as intensity and strength of movements has created an opportunity to contribute to the general wealth and comfort within these environments. Ambient Intelligence and Intelligent Decision Making processes can benefit from the knowledge gathered by these devices to improve decisions on everyday tasks such as deciding navigation routes by car, bicycle or other means of transportation and avoiding route perils. The concept of computational sustainability may also be applied to this problem. Current applications in this area demonstrate the usefulness of real time system that inform the user of certain conditions in the surrounding area. On the other hand, the approach presented in this work aims to describe models and approaches to automatically identify current states of traffic inside cities and use methods from computer science to improve overall comfort and the sustainability of road traffic both with the user and the environment in mind. Such objective is delivered by analyzing real time contributions from those mobile ubiquitous devices to identifying problematic situations and areas under a defined criteria that have significant influence towards a sustainable use of the road transport infrastructure.

  8. Modiifcation ofb-TCP/PLGA Scaffold and Its Effect on Bone Regeneration in vivo

    Institute of Scientific and Technical Information of China (English)

    LIN Liulan; GAO Haitao

    2016-01-01

    In order to look for the best proportion ofβ-tricalcium phosphate(β-TCP) and poly(lactide-co-glycolide) (PLGA) we fabricated porous compositesβ-TCP/PLGA scaffold using freeze-drying method. Morphological characterization using scanning electron microscopy showed that the interconnected pore distribution was even and there was no signiifcant difference with the increase of PLGA content. Moreover, the porosity, compressive strength and degradation in vitro were characterized. The fabricated scaffolds with increased PLGA in the compositesβ-TCP/PLGA scaffolds will get stronger mechanical property and better appearance, furthermore, get suitable environment for cells. According to the evaluation indexes for the tissue engineering scaffold, the group of scaffold (β-TCP/PLGA=6:4) was selected to evaluate the induced cell adhesion and proliferative ability of the scaffolds. Then as transplant embed into the bone critical defect sites on rats femur. The repairing processes of bone defect sites were characterized by X-ray analysis within 12 weeks. X-ray analysis showed that the bone defect sites all displayed the formation of callus obviously, In summary, our data suggest that the scaffold (β-TCP/PLGA=6:4) has a promising clinical future in regeneration of bone critical defects .

  9. LWD–TCP complex activates the morning gene CCA1 in Arabidopsis

    Science.gov (United States)

    Wu, Jing-Fen; Tsai, Huang-Lung; Joanito, Ignasius; Wu, Yi-Chen; Chang, Chin-Wen; Li, Yi-Hang; Wang, Ying; Hong, Jong Chan; Chu, Jhih-Wei; Hsu, Chao-Ping; Wu, Shu-Hsing

    2016-01-01

    A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock. PMID:27734958

  10. Performance Analysis of TCP and SCTP For Congestion Losses In Manet

    Directory of Open Access Journals (Sweden)

    Er.Amritpal Kaur

    2015-06-01

    Full Text Available Transmission control protocols have been used for data transmission process. TCP has been pre-owned for data transmission over wired communication having different bandwidths and message delays over the network. TCP provides communication using 3-handshake which sends RTS and ACK comes from server end and data message has been transmitted over the bandwidth provided. This does not provide security over flooding attack occurred on the network. TCP provides communication between different nodes of the wired communication but when multi-streaming occurs in a network TCP does not provides proper throughput of the system which is major problem that occurred in the previous system. In the proposed work, to overcome this problem SCTP transmission control protocol has been implemented for the system performance of the system. SCTP provides 4-handshake communication in the message transmit due to which security factor get increases and this also provides communication services over multi-streaming and multi-homing. Multiple sender and receivers can communicate over wired network using various approaches of communication through same routers, which degrades in the TCP protocol. In final we evaluate parameters for performance evaluation. Here, we designed and implemented our test bed using Network Simulator (NS-2.35 to test the performance of both Routing protocols.

  11. Edge isolation of transparent conductive polymer (TCP) thin films on flexible substrates using UV laser ablation.

    Science.gov (United States)

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei

    2012-06-01

    The purpose of this study was to directly use the writing techniques for the complex electrode edge isolation of transparent conductive polymer (TCP) thin films by a nanosecond pulsed UV laser processing system. The processing parameters including the laser pulse energy, the pulse repetition frequency, and the scan speed of galvanometers were examined to ablate the TCP films deposited on polyethylene terephtalate substrates of 188 microm thick. The thickness of TCP films was approximately 20 nm. The laser pulse repetition frequency and the scan speed of galvanometers were applied to calculate the overlapping rate of laser spots and to discuss the patterning region quality. Surface morphology, edge quality, and width and depth of edge isolated patterning structures after laser ablation process were measured by a three-dimensional confocal laser scanning microscope. In addition, the electrical conductivity of ablated TCP films was measured by a four-point probes instrument. After isolated line patterning was formed, the ablated TCP films with a better edge quality were obtained directly when the overlapping rate of laser spots, the scan speed, and the pulse repetition rate were 83.3%, 200 mm/s, and 40 kHz, respectively. The better surface morphology of electrode pattern structures was also obtained when the scan speed and the pulse repetition rate were 500 mm/s and 40 kHz, respectively.

  12. A More Complete Model for TCP Connections Established between One Server and Many Receivers

    Institute of Scientific and Technical Information of China (English)

    LINYu; CHENGShiduan; WUHaitao; WANGChonggang

    2003-01-01

    Different from previous TCP (transmis-sion control program) modeling works, this paper presents a more complete analytical model of multiple TCP con-nections established between a busy server and multiple receivers under two distinct cases: the case there is suffi-cient bandwidth and the case there is a bandwidth bottle-neck link between the server and receivers. In the former case, the server will become the bottleneck of the whole system, and TCP behaviors are different from the model presented before. However, in the latter case, multiple TCP connections will share the bandwidth of the bottle-neck link. Based on the analysis of working flows in the system and a M/G/1 queueing model, the RTT and long-term TCP throughput formulae are derived in terms of number of TCPs, packet loss rate, and end-to-end delay.And the effect of maximum window size is also investi-gated. The simulation results confirm that new model is more accurate than previous model.

  13. Fabrication of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering.

    Science.gov (United States)

    Lou, Tao; Wang, Xuejun; Song, Guojun; Gu, Zheng; Yang, Zhen

    2014-08-01

    Polymer and ceramic composite scaffolds play a crucial role in bone tissue engineering. In an attempt to mimic the architecture of natural extracellular matrix (ECM), poly(l-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) nanocomposite scaffolds with a hierarchical pore structure were fabricated by combining thermal induced phase separation and salt leaching techniques. The nanocomposite scaffold consisted of a nanofibrous PLLA matrix with a highly interconnected, high porosity (>93%) hierarchical pore structure with pore diameters ranging from 500nm to 300μm and a homogeneously distributed β-TCP nanoparticle phase. The nanofibrous PLLA matrix had a fiber diameter of 70-300nm. The nanocomposite scaffolds possess three levels of hierarchical structure: (1) porosity; (2) nanofibrous PLLA struts comprising the pore walls; and (3) β-TCP nanoparticle phase. The β-TCP nanoparticle phase improved the mechanical properties and bioactivity of the PLLA matrix. The nanocomposite scaffolds supported MG-63 osteoblast proliferation, penetration, and ECM deposition, indicating the potential of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering applications.

  14. Identification of two combined genes responsible for dechlorination of 3,5,6-trichloro-2-pyridinol (TCP) in Cupriavidus pauculus P2.

    Science.gov (United States)

    Cao, Li; Xu, Jianhong; Wu, Guang; Li, Mingxing; Jiang, Jiandong; He, Jian; Li, Shunpeng; Hong, Qing

    2013-09-15

    Dehalogenation is an important mechanism for degrading and detoxifying halogenated aromatics in microbes. However, the biochemical and molecular mechanisms of dehalogenation of 3,5,6-trichloro-2-pyridinol (TCP) are still unknown. In this study, a novel 6012 bp gene cluster was cloned from TCP-degrading strain P2, which was responsible for the dehalogenation of TCP. The cluster included a monooxygenase gene (tcpA1), a flavin reductase gene (tcpB1), tcpR1, orf1 and orf2. TcpA1 and TcpB1 were indispensable for the dehalogenation of TCP. They worked together to catalyze the dehalogenation of three chlorine of TCP, and generated a more readily biodegradable product of 3,6-dihydroxypyridine-2,5-dione. TcpA1 displayed the highest activity against TCP at 40°C and at pH 8.0. Cu(2+), Zn(2+), and Hg(2+) significantly inhibited enzyme activity. To the best of our knowledge, this is the first report on a gene cluster responsible for TCP degradation.

  15. Lagrangian Multi-Class Traffic State Estimation

    OpenAIRE

    Yuan, Y.

    2013-01-01

    Road traffic is important to everybody in the world. People travel and commute everyday. For those who travel by cars (or other types of road vehicles), traffic congestion is a daily experience. One essential goal of traffic researchers is to reduce traffic congestion and to improve the whole traffic system operation and the environment. To achieve this goal, we have to first understand prevailing traffic situations, then perform pro-active traffic control and management. The estimation of tr...

  16. Real time traffic models, decision support for traffic management

    OpenAIRE

    Wismans, L.; De Romph, E.; Friso, K.; Zantema, K.

    2014-01-01

    Reliable and accurate short-term traffic state prediction can improve the performance of real-time traffic management systems significantly. Using this short-time prediction based on current measurements delivered by advanced surveillance systems will support decision-making processes on various control strategies and enhance the performance of the overall network. By taking proactive action deploying traffic management measures, congestion may be prevented or its effects limited. An approach...

  17. Alternate Routing in Tandem Traffic-Groomed Optical Networks

    Directory of Open Access Journals (Sweden)

    Alicia Nicki Washington

    2007-09-01

    Full Text Available Recent advances in telecommunication networks have allowed WDM to emerge as a viable solution to the ever-increasing demands of the Internet. Because these networks carry large amounts of traffic, alternate routing methods are designed in order to allow traffic to be properly re-routed from source to destination in the event of certain events, such as link blocking or failure. In this paper, we consider a tandem traffic-groomed optical network, modeled as a multi-level overflow system, where each level represents a wavelength between adjacent nodes. The queueing network is analyzed using a combination of methods. As will be shown, the decomposition method provides a good approximate analysis of large overflow systems supporting traffic from multiple sources.

  18. KINEMATIC WAVE PROPERTIES OF ANISOTROPIC DYNAMICS MODEL FOR TRAFFIC FLOW

    Institute of Scientific and Technical Information of China (English)

    姜锐; 吴清松; 朱祚金

    2002-01-01

    The analyses of kinematic wave properties of a new dynamics model for traffic flow are carried out. The model does not exhibit the problem that one characteristic speed is always greater than macroscopic traffic speed, and therefore satisfies the requirement that traffic flow is anisotropic. Linear stability analysis shows that the model is stable under certain condition and the condition is obtained. The analyses also indicate that the model has a hierarchy of first-and second-order waves, and allows the existence of both smooth traveling wave and shock wave. However, the model has a distinctive criterion of shock wave compared with other dynamics models, and the distinction makes the model more realistic in dealing with some traffic problems such as wrong-way travel analysis.

  19. Traffic Games: Modeling Freeway Traffic with Game Theory.

    Science.gov (United States)

    Cortés-Berrueco, Luis E; Gershenson, Carlos; Stephens, Christopher R

    2016-01-01

    We apply game theory to a vehicular traffic model to study the effect of driver strategies on traffic flow. The resulting model inherits the realistic dynamics achieved by a two-lane traffic model and aims to incorporate phenomena caused by driver-driver interactions. To achieve this goal, a game-theoretic description of driver interaction was developed. This game-theoretic formalization allows one to model different lane-changing behaviors and to keep track of mobility performance. We simulate the evolution of cooperation, traffic flow, and mobility performance for different modeled behaviors. The analysis of these results indicates a mobility optimization process achieved by drivers' interactions.

  20. Traffic Games: Modeling Freeway Traffic with Game Theory

    Science.gov (United States)

    Cortés-Berrueco, Luis E.; Gershenson, Carlos; Stephens, Christopher R.

    2016-01-01

    We apply game theory to a vehicular traffic model to study the effect of driver strategies on traffic flow. The resulting model inherits the realistic dynamics achieved by a two-lane traffic model and aims to incorporate phenomena caused by driver-driver interactions. To achieve this goal, a game-theoretic description of driver interaction was developed. This game-theoretic formalization allows one to model different lane-changing behaviors and to keep track of mobility performance. We simulate the evolution of cooperation, traffic flow, and mobility performance for different modeled behaviors. The analysis of these results indicates a mobility optimization process achieved by drivers’ interactions. PMID:27855176

  1. Research and implementation of TCP/IP stack suitable for thin embedded server%嵌入式瘦服务器中TCP/IP协议栈的研究与实现

    Institute of Scientific and Technical Information of China (English)

    阙建荣; 卿立军

    2004-01-01

    文章分析和研究了嵌入式Intenet技术中应用于嵌入式瘦服务器的TCP/IP协议栈的特点.在此基础上设计并实现了一种适合于嵌入式瘦服务器的TCP/IP协议栈-emIP.

  2. Cascade Probability Control to Mitigate Bufferbloat under Multiple Real-World TCP Stacks

    Directory of Open Access Journals (Sweden)

    Hoang-Linh To

    2015-01-01

    Full Text Available Persistently full buffer problem, commonly known as bufferbloat, causes unnecessary additional latency and throughput degradation whenever congestion happens in Internet. Several proposed queue management schemes, with the debloat mission, are almost based on the modification of one-loop feedback control where the instability and bad transient behavior are still big challenges. In this paper, we present a cascade probability control scheme using margin optimal method to address such challenges under different kinds of real-world TCP stacks. Simulation results guarantee the measured round trip time tracking to a low value of delay (e.g., ≈180 ms under TCP Reno, and ≈130 ms under TCP Cubic and ≈50% delay reduction in comparison to current deployed queue management schemes in network devices.

  3. Study on β-TCP Coated Porous Mg as a Bone Tissue Engineering Scaffold Material

    Institute of Scientific and Technical Information of China (English)

    Fang Geng; Lili Tan; Bingchun Zhang; Chunfu Wu; Yonglian He; Jingyu Yang; Ke Yang

    2009-01-01

    Three-dimensional honeycomb-structured magnesium (Mg) scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactive β-tricalcium phosphate (β-TCP) coatings were prepared on the porous Mg to further improve its biocompatibility, and the biodegradation mechanism was simply evaluated in vitro. It was found that the mechanical properties of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed that the human osteosarcoma cells (UMR106) were well adhered and proliferated on the surface of the β-TCP coated porous Mg, which indicates that the β-TCP coated porous Mg is promising to be a bone tissue engineering scaffold material.

  4. Rapid restoration of methanogenesis in an acidified UASB reactor treating 2,4,6-trichlorophenol (TCP).

    Science.gov (United States)

    Díaz-Báez, María Consuelo; Valderrama-Rincon, Juan Daniel

    2017-02-15

    Anaerobic bioreactors are often used for removal of xenobiotic and highly toxic pollutants from wastewater. Most of the time, the pollutant is so toxic that the stability of the reactor becomes compromised. It is well known that methanogens are one of the most sensitive organisms in the anaerobic consortia and hence the stability of the reactors is highly dependant on methanogenesis. Unfortunately few studies have focused on recovering the methanogenic activity once it has been inhibited by highly toxic pollutants. Here we establish a quick recovery strategy for neutralization of an acidified UASB reactor after failure by intoxication with an excess of TCP in the influent. Once the reactor returned to pH values compatible with methanogenesis, biogas production was re-started after one day and the system was re-acclimated to TCP. Successful removal of TCP from synthetic wastewater was shown for concentrations up to 70mg/L after restoration.

  5. An Advance Approach to Evaluate the Performance of the TCP Networks

    Directory of Open Access Journals (Sweden)

    Ibrahiem M.M. El Emary

    2005-01-01

    Full Text Available In this study, we present a new approach for estimating the performance of the TCP network depending on a mathematical formula which converts the conceptual performance parameter to a valuable one. With respect to TCP network performance, we consider the Random Early Detection (RED and RED-Based algorithms where both RED and RED-Based follow the Active Queue Management (AQM approach in TCP networks. Mainly, we make a comprehensive understanding of various network parameters that continually affect the network performance. The main parameters that are used given by: network throughput, link utilization, network average delay, and packet loss rate. Also in this study, we estimate a new parameter reflecting the network performance called Network Quality Parameter (NQP.

  6. A GA-based PID active queue management control design for TCP/IP networks

    Science.gov (United States)

    Kuo, H.-H.; Chen, C.-K.; Yan, J.-J.; Liao, T.-L.

    2008-02-01

    In this paper, a genetic algorithm-based (GA-based) proportional-integral-derivative (PID) controller as an active queue manager for Internet routers is proposed to reduce packet loss and improve network utilization in TCP/IP networks. Based on the window-based nonlinear dynamics, the TCP network was modeled as a time-delayed system with a saturated input due to the limitations of packet-dropping probability and the effects of propagation delays in TCP networks. An improved genetic algorithm is employed to derive optimal or near optimal PID control gains such that a performance index of integrated-absolute error (IAE) in terms of the error between the router queue length and the desired queue length is minimized. The performance of the proposed control scheme was evaluated in various network scenarios via a series of numerical simulations. The simulation results confirm that the proposed scheme outperforms other AQM schemes.

  7. Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial Networks

    CERN Document Server

    Vinayakray-Jani, Preetida

    2012-01-01

    Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system is having strong resemblance to terrestrial GSM (Global System for Mobile communications) at the upper protocol layers and TCP (Transmission Control Protocol) is one of them. This space segment technology as well as terrestrial technology, is characterized by periodic variations in communication properties and coverage causing the termination of ongoing call as connections of Mobile Nodes (MN) alter stochastically. Although provisions are made to provide efficient communication infrastructure this hybrid space and terrestrial networks must ensure the end-to-end network performance so that MN can move seamlessly among these networks. However from connectivity point of view current TCP performance has not been engineered for mobility events in multi-radio MN. Traditionally, TCP has applied a set of congestion control algorithms (slow-start, congestion avoidance, fast retransmit, fast recovery) to probe the currently available bandwidth on...

  8. Improved virtual queuing and dynamic EPD techniques for TCP over ATM

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Siu, K.Y.; Ren, W.

    1998-11-01

    It is known that TCP throughput can degrade significantly over UBR service in a congested ATM network, and the early packet discard (EPD) technique has been proposed to improve the performance. However, recent studies show that EPD cannot ensure fairness among competing VCs in a congested network, but the degree of fairness can be improved using various forms of fair buffer allocation techniques. The authors propose an improved scheme that utilizes only a single shared FIFO queue for all VCs and admits simple implementation for high speed ATM networks. The scheme achieves nearly perfect fairness and throughput among multiple TCP connections, comparable to the expensive per-VC queuing technique. Analytical and simulation results are presented to show the validity of this new scheme and significant improvement in performance as compared with existing fair buffer allocation techniques for TCP over ATM.

  9. An Analysis of English Carrie

    Institute of Scientific and Technical Information of China (English)

    孙淑珍

    2004-01-01

    @@ Chapter Ⅰ Introduction Sitting in the rocking chair,Carrie dreams her future.This is the deep impression the novel"Sister Carrie"gives us,which is written by Theodore Dreiser(1871-1945),the great American realism writer.

  10. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior

    Science.gov (United States)

    Czisch, Christopher; Witek, Lukasz; Shi, Yang; Smay, Jim; Plant, Giles W.; Yang, Yunzhi

    2015-01-01

    Numerous studies have demonstrated that Schwann cells (SCs) play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP) scaffolds arranged in 3D printed-lattice (P-β-TCP) and randomly-porous, template-casted (N-β-TCP) structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf), neutrophin–3 (nt–3), platelet-derived growth factor (pdgf-bb), and vascular endothelial growth factor (vegf-a) were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts. PMID:26444999

  11. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior.

    Directory of Open Access Journals (Sweden)

    Lauren Sweet

    Full Text Available Numerous studies have demonstrated that Schwann cells (SCs play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP scaffolds arranged in 3D printed-lattice (P-β-TCP and randomly-porous, template-casted (N-β-TCP structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf, neutrophin-3 (nt-3, platelet-derived growth factor (pdgf-bb, and vascular endothelial growth factor (vegf-a were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts.

  12. Genome-Wide Identification, Characterization and Expression Analysis of the TCP Gene Family in Prunus mume

    Science.gov (United States)

    Zhou, Yuzhen; Xu, Zongda; Zhao, Kai; Yang, Weiru; Cheng, Tangren; Wang, Jia; Zhang, Qixiang

    2016-01-01

    TCP proteins, belonging to a plant-specific transcription factors family, are known to have great functions in plant development, especially flower and leaf development. However, there is little information about this gene family in Prunus mume, which is widely cultivated in China as an ornamental and fruit tree. Here a genome-wide analysis of TCP genes was performed to explore their evolution in P. mume. Nineteen PmTCPs were identified and three of them contained putative miR319 target sites. Phylogenetic and comprehensive bioinformatics analyses of these genes revealed that different types of TCP genes had undergone different evolutionary processes and the genes in the same clade had similar chromosomal location, gene structure, and conserved domains. Expression analysis of these PmTCPs indicated that there were diverse expression patterns among different clades. Most TCP genes were predominantly expressed in flower, leaf, and stem, and showed high expression levels in the different stages of flower bud differentiation, especially in petal formation stage and gametophyte development. Genes in TCP-P subfamily had main roles in both flower development and gametophyte development. The CIN genes in double petal cultivars might have key roles in the formation of petal, while they were correlated with gametophyte development in the single petal cultivar. The CYC/TB1 type genes were highly detected in the formation of petal and pistil. The less-complex flower types of P. mume might result from the fact that there were only two CYC type genes present in P. mume and a lack of CYC2 genes to control the identity of flower types. These results lay the foundation for further study on the functions of TCP genes during flower development. PMID:27630648

  13. Incorporation of RANKL promotes osteoclast formation and osteoclast activity on β-TCP ceramics.

    Science.gov (United States)

    Choy, John; Albers, Christoph E; Siebenrock, Klaus A; Dolder, Silvia; Hofstetter, Wilhelm; Klenke, Frank M

    2014-12-01

    β-Tricalcium phosphate (β-TCP) ceramics are approved for the repair of osseous defects. In large defects, however, the substitution of the material by authentic bone is inadequate to provide sufficient long-term mechanical stability. We aimed to develop composites of β-TCP ceramics and receptor activator of nuclear factor κ-B ligand (RANKL) to enhance the formation of osteoclasts and promote cell mediated calcium phosphate resorption. RANKL was adsorbed superficially onto β-TCP ceramics or incorporated into a crystalline layer of calcium phosphate by the use of a co-precipitation technique. Murine osteoclast precursors were seeded onto the ceramics. After 15 days, the formation of osteoclasts was quantified cytologically and colorimetrically with tartrate-resistant acidic phosphatase (TRAP) staining and TRAP activity measurements, respectively. Additionally, the expression of transcripts encoding the osteoclast gene products cathepsin K, calcitonin receptor, and of the sodium/hydrogen exchanger NHA2 were quantified by real-time PCR. The activity of newly formed osteoclasts was evaluated by means of a calcium phosphate resorption assay. Superficially adsorbed RANKL did not induce the formation of osteoclasts on β-TCP ceramics. When co-precipitated onto β-TCP ceramics RANKL supported the formation of mature osteoclasts. The development of osteoclast lineage cells was further confirmed by the increased expression of cathepsin K, calcitonin receptor, and NHA2. Incorporated RANKL stimulated the cells to resorb crystalline calcium phosphate. Our in vitro study shows that RANKL incorporated into β-TCP ceramics induces the formation of active, resorbing osteoclasts on the material surface. Once formed, osteoclasts mediate the release of RANKL thereby perpetuating their differentiation and activation. In vivo, the stimulation of osteoclast-mediated resorption may contribute to a coordinated sequence of material resorption and bone formation. Further in vivo studies

  14. Solid state synthesis and thermal stability of HAP and HAP - beta-TCP composite ceramic powders.

    Science.gov (United States)

    Rao, R R; Roopa, H N; Kannan, T S

    1997-08-01

    Powders of pure beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HAP) and a biphasic composite mixture of HAP+beta-TCP were prepared by solid state reaction between two commercially available calcium-based precursors namely, tricalcium phosphate (TCP) and calcium hydroxide (Ca(OH)2). These reactants mixed in the molar ratios ranging from 3 : 0 to 3 : 4 (designated T0 to T4) in deionized water, milled and slip-cast into discs were heat treated in the temperature range of 600 degrees C to 1250 degrees C. The products formed were characterized by X-ray diffraction (XRD) and i.r. spectroscopic techniques for identification of phases formed and functional groups present in them. While tricalcium phosphate and calcium hydroxide taken in the molar ratio of 3 : 2 and 3 : 3 resulted in pure HAP when heat treated at 1000 degrees C for 8 h, the 3 : 1 and 3 : 1.5 molar ratio compositions resulted in a biphasic mixture of HAP+beta-TCP for similar heat treatments. Heat treatment of 3 : 4 molar ratio composition of tricalcium phosphate and calcium hydroxide at 1000 degrees C yielded HAP with free CaO as the secondary phase. Products of heat treatment at higher temperatures (1150 and 1250 degrees C) for even shorter duration (2 h) while not differing from the products obtained from T0 and T2 cases at 1000 degrees C (pure beta-TCP and pure HAP), change in the case of T1, T1.5, T3 and T4 to products with lesser percentages of HAP containing beta-TCP (in the case of T1 and T1.5) or CaO (in the case of T3 and T4) as the secondary phase.

  15. Determination of physical properties for β-TCP + chitosan biomaterial obtained on metallic 316L substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Tecno-Academia ASTIN SENA Reginal Valle (Colombia); Castaño, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, J.C., E-mail: julio.cesar.caicedo@correo.univalle.edu.co [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, H.H. [Biologics Research, Biotechnology Center of Excellence, Janssen R& D, LLC, Pharmaceutical Companies of Johnson & Johnson, Spring House, PA 19477 (United States); National Biotechnology & Pharmaceutical Association, Chicago, IL 60606 (United States); Aguilar, Y. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia)

    2015-06-15

    Material surface modification, particularly the deposition of special coatings on the surface of surgical implants, is extensively used in bone tissue engineering applications. β-Tricalcium phosphate/Chitosan (β-TCP/Ch) coatings were deposited on 316L stainless steel (316L SS) substrates by a cathodic electro-deposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-Ray diffraction (XRD), and the results indicated that the crystallographic structure of β-TCP was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that root-mean square values of the β-TCP/Ch coatings decreased by further increasing chitosan percentage. The elastic–plastic characteristics of the coatings were determined by conducting nanoindentation test, indicating that increase of chitosan percentage is directly related to increase of hardness and elastic modulus of the β-TCP/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear of β-TCP/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-TCP/Ch coatings as a function of increasing of the chitosan percentage. This new class of coatings, comprising the bioactive components, is expected not only to enhance the bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. - Highlights: • Superficial phenomenon that occurs in tribological surface of β-tricalcium phosphate-chitosan coatings. • Improvement on surface mechanical properties of ceramic-polymeric and response to surface tribological damage. • β-tricalcium phosphate-chitosan coatings that offer highest performance in the biomedical devices.

  16. On differences in radiosensitivity estimation: TCP experiments versus survival curves. A theoretical study

    Science.gov (United States)

    Stavrev, Pavel; Stavreva, Nadejda; Ruggieri, Ruggero; Nahum, Alan

    2015-08-01

    We have compared two methods of estimating the cellular radiosensitivity of a heterogeneous tumour, namely, via cell-survival and via tumour control probability (TCP) pseudo-experiments. It is assumed that there exists intra-tumour variability in radiosensitivity and that the tumour consists predominantly of radiosensitive cells and a small number of radio-resistant cells. Using a multi-component, linear-quadratic (LQ) model of cell kill, a pseudo-experimental cell-survival versus dose curve is derived. This curve is then fitted with a mono-component LQ model describing the response of a homogeneous cell population. For the assumed variation in radiosensitivity it is shown that the composite pseudo-experimental survival curve is well approximated by the survival curve of cells with uniform radiosensitivity. For the same initial cell radiosensitivity distribution several pseudo-experimental TCP curves are simulated corresponding to different fractionation regimes. The TCP model used accounts for clonogen proliferation during a fractionated treatment. The set of simulated TCP curves is then fitted with a mono-component TCP model. As in the cell survival experiment the fit with a mono-component model assuming uniform radiosensitivity is shown to be highly acceptable. However, the best-fit values of cellular radiosensitivity produced via the two methods are very different. The cell-survival pseudo-experiment yields a high radiosensitivity value, while the TCP pseudo-experiment shows that the dose-response is dominated by the most resistant sub-population in the tumour, even when this is just a small fraction of the total.

  17. Genome-Wide Identification, Characterization and Expression Analysis of the TCP Gene Family in Prunus mume.

    Science.gov (United States)

    Zhou, Yuzhen; Xu, Zongda; Zhao, Kai; Yang, Weiru; Cheng, Tangren; Wang, Jia; Zhang, Qixiang

    2016-01-01

    TCP proteins, belonging to a plant-specific transcription factors family, are known to have great functions in plant development, especially flower and leaf development. However, there is little information about this gene family in Prunus mume, which is widely cultivated in China as an ornamental and fruit tree. Here a genome-wide analysis of TCP genes was performed to explore their evolution in P. mume. Nineteen PmTCPs were identified and three of them contained putative miR319 target sites. Phylogenetic and comprehensive bioinformatics analyses of these genes revealed that different types of TCP genes had undergone different evolutionary processes and the genes in the same clade had similar chromosomal location, gene structure, and conserved domains. Expression analysis of these PmTCPs indicated that there were diverse expression patterns among different clades. Most TCP genes were predominantly expressed in flower, leaf, and stem, and showed high expression levels in the different stages of flower bud differentiation, especially in petal formation stage and gametophyte development. Genes in TCP-P subfamily had main roles in both flower development and gametophyte development. The CIN genes in double petal cultivars might have key roles in the formation of petal, while they were correlated with gametophyte development in the single petal cultivar. The CYC/TB1 type genes were highly detected in the formation of petal and pistil. The less-complex flower types of P. mume might result from the fact that there were only two CYC type genes present in P. mume and a lack of CYC2 genes to control the identity of flower types. These results lay the foundation for further study on the functions of TCP genes during flower development.

  18. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior.

    Science.gov (United States)

    Sweet, Lauren; Kang, Yunqing; Czisch, Christopher; Witek, Lukasz; Shi, Yang; Smay, Jim; Plant, Giles W; Yang, Yunzhi

    2015-01-01

    Numerous studies have demonstrated that Schwann cells (SCs) play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP) scaffolds arranged in 3D printed-lattice (P-β-TCP) and randomly-porous, template-casted (N-β-TCP) structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf), neutrophin-3 (nt-3), platelet-derived growth factor (pdgf-bb), and vascular endothelial growth factor (vegf-a) were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts.

  19. In vitro neurotoxic hazard characterization of different tricresyl phosphate (TCP) isomers and mixtures.

    Science.gov (United States)

    Duarte, Daniel J; Rutten, Joost M M; van den Berg, Martin; Westerink, Remco H S

    2016-02-03

    Exposure to tricresyl phosphates (TCPs), via for example contaminated cabin air, has been associated with health effects including the so-called aerotoxic syndrome. While TCP neurotoxicity is mainly attributed to ortho-isomers like tri-ortho-cresyl phosphate (ToCP), recent exposure and risk assessments indicate that ToCP levels in cabin air are very low. However, the neurotoxic potential of non-ortho TCP isomers and TCP mixtures is largely unknown. We therefore measured effects of exposure (up to 48h) to different TCP isomers, mixtures and the metabolite of ToCP (CBDP: cresyl saligenin phosphate) on cell viability and mitochondrial activity, spontaneous neuronal electrical activity, and neurite outgrowth in primary rat cortical neurons. The results demonstrate that exposure to TCPs (24-48h, up to 10μM) increases mitochondrial activity, without affecting cell viability. Effects of acute TCP exposure (30min) on neuronal electrical activity are limited. However, electrical activity is markedly decreased for the majority of TCPs (10μM) following 48h exposure. Additional preliminary data indicate that exposure to TCPs (48h, 10μM) did not affect the number of neurites per cell or average neurite length, except for TmCP and the analytical TCP mixture (Sigma) that induced a reduction of average neurite length. The combined neurotoxicity data demonstrate that the different TCPs, including ToCP, are roughly equipotent and a clear structure-activity relation is not apparent for the studied endpoints. The no-observed-effect-concentrations (1μM) are well above current exposure levels indicating limited neurotoxic health risk, although exposures may have been higher in the past. Moreover, prolonged and/or repeated exposure to TCPs may exacerbate the observed neurotoxic effects, which argues for additional research.

  20. The Arabidopsis thaliana TCP transcription factors: A broadening horizon beyond development.

    Science.gov (United States)

    Li, Shutian

    2015-01-01

    The TCP family of transcription factors is named after the first 4 characterized members, namely TEOSINTE BRANCHED1 (TB1) from maize (Zea mays), CYCLOIDEA (CYC) from snapdragon (Antirrhinum majus), as well as PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR1 (PCF1) and PCF2 from rice (Oryza sativa). Phylogenic analysis of this plant-specific protein family unveils a conserved bHLH-containing DNA-binding motif known as the TCP domain. In accordance with the structure of this shared domain, TCP proteins are grouped into class I (TCP-P) and class II (TCP-C), which are suggested to antagonistically modulate plant growth and development via competitively binding similar cis-regulatory modules called site II elements. Over the last decades, TCPs across the plant kingdom have been demonstrated to control a plethora of plant processes. Notably, TCPs also regulate plant development and defense responses via stimulating the biosynthetic pathways of bioactive metabolites, such as brassinosteroid (BR), jasmonic acid (JA) and flavonoids. Besides, mutagenesis analysis coupled with biochemical experiments identifies several crucial amino acids located within the TCP domain, which confer the redox sensitivity of class I TCPs and determine the distinct DNA-binding properties of TCPs. In this review, developmental functions of TCPs in various biological pathways are briefly described with an emphasis on their involvement in the synthesis of bioactive substances. Furthermore, novel biochemical aspects of TCPs with respect to redox regulation and DNA-binding preferences are elaborated. In addition, the unexpected participation of TCPs in effector-triggered immunity (ETI) and defense against insects indicates that the widely recognized developmental regulators are capable of fine-tuning defense signaling and thereby enable plants to evade deleterious developmental phenotypes. Altogether, these recent impressive breakthroughs remarkably advance our understanding as to how TCPs integrate

  1. Framework for Traffic Congestion Management

    OpenAIRE

    Mahmud Hassan TALUKDAR

    2013-01-01

    Traffic Congestion is one of many serious global problems in all great cities resulted from rapid urbanization which always exert negative externalities upon society. The solution of traffic congestion is highly geocentric and due to its heterogeneous nature, curbing congestion is one of the hard tasks for transport planners. It is not possible to suggest unique traffic congestion management framework which could be absolutely applied for every great cities. Conversely, it is quite feasible t...

  2. Osteoconductivity and Biodegradability of Collagen Scaffold Coated with Nano-β-TCP and Fibroblast Growth Factor 2

    Directory of Open Access Journals (Sweden)

    Asako Ibara

    2013-01-01

    Full Text Available Nanoparticle bioceramics have become anticipated for biomedical applications. Highly bioactive and biodegradable scaffolds would be developed using nanoparticles of β-tricalcium phosphate (β-TCP. We prepared collagen scaffolds coated by nano-β-TCP and fibroblast growth factor 2 (FGF2 and evaluated the effects on new bone augmentation and biodegradation. The collagen sponge was coated with the nano-TCP dispersion and freeze-dried. Scaffold was characterized by SEM, TEM, XRD, compressive testing and cell seeding. Subsequently, the nano-β-TCP/collagen scaffold, collagen sponge, and each material loaded with FGF2 were implanted on rat cranial bone. As a control, no implantation was performed. Nano-TCP particles were found to be attached to the fibers of the collagen sponge by SEM and TEM observations. Scaffold coated with nano-TCP showed higher compressive strength and cytocompatibility. In histological evaluations at 10 days, inflammatory cells were rarely seen around the residual scaffold, suggesting that the nano-TCP material possesses good tissue compatibility. At 35 days, bone augmentation and scaffold degradation in histological samples receiving nano-β-TCP scaffold were significantly greater than those in the control. By loading of FGF2, advanced bone formation is facilitated, indicating that a combination with FGF2 would be effective for bone tissue engineering.

  3. Leaf expansion in Arabidopsis is controlled by a TCP-NGA regulatory module likely conserved in distantly related species.

    Science.gov (United States)

    Ballester, Patricia; Navarrete-Gómez, Marisa; Carbonero, Pilar; Oñate-Sánchez, Luis; Ferrándiz, Cristina

    2015-09-01

    The NGATHA (NGA) clade of transcription factors (TFs) forms a small subfamily of four members in Arabidopsis thaliana. NGA genes act redundantly to direct the development of apical tissues in the gynoecium, where they have been shown to be essential for style and stigma specification. In addition, NGA genes have a more general role in controlling lateral organ growth. The four NGA genes in Arabidopsis are expressed in very similar domains, although little is known about the nature of their putative regulators. Here, we have identified a conserved region within the four NGA promoters that we have used as a bait to screen a yeast library, aiming to identify such NGA regulators. Three members of the TCP family of TFs, named after the founding factors TEOSINTE BRANCHED 1, CYCLOIDEA and PROLIFERATING CELL FACTOR 1 AND 2), were recovered from this screening, of which two [TCP2 and TCP3, members of the CINCINNATA (CIN) family of TCP genes (CIN-TCP) subclade] were shown to activate the NGA3 promoter in planta. We provide evidence that support that CIN-TCP genes are true regulators of NGA gene expression, and that part of the CIN-TCP role in leaf development is mediated by NGA upregulation. Moreover, we have found that this TCP-NGA regulatory interaction is likely conserved in angiosperms, including important crop species, for which the regulation of leaf development is a target for biotechnological improvement.

  4. Traffic forecasts ignoring induced demand

    DEFF Research Database (Denmark)

    Næss, Petter; Nicolaisen, Morten Skou; Strand, Arvid

    2012-01-01

    Although the phenomenon of induced traffic has been theorized for more than 60 years and is now widely accepted among transport researchers, the traffic-generating effects of road capacity expansion are still often neglected in transport modelling. Such omission can lead to serious bias in the as......Although the phenomenon of induced traffic has been theorized for more than 60 years and is now widely accepted among transport researchers, the traffic-generating effects of road capacity expansion are still often neglected in transport modelling. Such omission can lead to serious bias...

  5. Road traffic noise and stroke

    DEFF Research Database (Denmark)

    Sørensen, Mette; Hvidberg, Martin; Andersen, Zorana J

    2011-01-01

    Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before.......Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before....

  6. A New Approach for Performance Evaluation of TCP over Interference-Limited Wireless Channels

    Institute of Scientific and Technical Information of China (English)

    LUO Rui; FAN Pingzhi

    2003-01-01

    A new metric for performance evaluation of transport control protocol(TCP) over wireless channels based on the interference-limited characteristics of code division multiple address(CDMA) system is proposed. According to the new metric, the performance of TCP over CDMA correlated channel for different protocol parameters and different versions is investigated. The results show that appropriate selection of protocol parameters and packet error rate(PER) operation point can improve significantly the capacity of packet-switched CDMA-based network.

  7. [Multi-bed & multi-parameter central monitoring system based on TCP/IP protocol].

    Science.gov (United States)

    Lian, S J; Hu, D K; Zhao, M H; Tang, L H

    2000-02-01

    Communication is one of the key problems to a central monitoring system. In this paper we put forward a central monitoring system using TCP/IP as the network protocol, Windows NT4.0 as the platform, forming a Intranet in a hospital. We also discussed the communication problem between the bed-side monitoring station and the central monitoring station in detail and then put forward a new protocol--Hospital Central Monitor Protocol (HCMP) based on TCP/IP to transfer monitoring data. It is easy to achieve tele-monitoring through the current communication subsystem.

  8. Robustness of Multiple High Speed TCP CUBIC Connections Under Severe Operating Conditions

    DEFF Research Database (Denmark)

    Pilimon, Artur; Ruepp, Sarah Renée; Berger, Michael Stübert

    2015-01-01

    We study the adaptation capabilities and robustness of the high-speed TCP CUBIC algorithm. For this purpose we consider a network environment with variable and high random packet loss and a large Bandwidth-Delay product, shared by multiple heterogeneous TCP connections. The analysis is based...... on and supported by packet-level simulations. The results show that the aggressive nature of CUBIC’s nonlinear congestion window control principle causes a degradation of the time-average throughput at the moderate level of random packet loss even under increasing Round-Trip-Time of the flow. However...

  9. TCP over low-power and lossy networks: tuning the segment size to minimize energy consumption

    CERN Document Server

    Ayadi, Ahmed; Ros, David

    2010-01-01

    Low-power and Lossy Networks (LLNs), like wireless networks based upon the IEEE 802.15.4 standard, have strong energy constraints, and are moreover subject to frequent transmission errors, not only due to congestion but also to collisions and to radio channel conditions. This paper introduces an analytical model to compute the total energy consumption in an LLN due to the TCP protocol. The model allows us to highlight some tradeoffs as regards the choice of the TCP maximum segment size, of the Forward Error Correction (FEC) redundancy ratio, and of the number of link-layer retransmissions, in order to minimize the total energy consumption.

  10. CER/TER - The New Metric for TCP Connection Robustness Evaluation and Comparison

    Directory of Open Access Journals (Sweden)

    Ondrej Vondrous

    2015-01-01

    Full Text Available This article presents new metric for TCP connection robustness evaluation and comparison. This metric is focused on TCP connection and transmission continuity rather then on maximal throughput or minimal RTT. This metric is developed especially for evaluation of narrow band networks. That is why it is very convenient to use this metric for networks such as Internet of Things networks or industrial sensor networks. Our metric is based on observing if connections or transmissions are successfully finished or not. It is possible to optimize this metric for specific situations. This metric can be used in both the real networks and in discrete simulation environments.

  11. SCPS-TP, TCP, and Rate-Based Protocol Evaluation. Revised

    Science.gov (United States)

    Tran, Diepchi T.; Lawas-Grodek, Frances J.; Dimond, Robert P.; Ivancic, William D.

    2005-01-01

    Tests were performed at Glenn Research Center to compare the performance of the Space Communications Protocol Standard Transport Protocol (SCPS TP, otherwise known as "TCP Tranquility") relative to other variants of TCP and to determine the implementation maturity level of these protocols, particularly for higher speeds. The testing was performed over reasonably high data rates of up to 100 Mbps with delays that are characteristic of near-planetary environments. The tests were run for a fixed packet size, but for variously errored environments. This report documents the testing performed to date.

  12. Reducing Communication Overhead by Scheduling TCP Transfers on Mobile Devices using Wireless Network Performance Maps

    DEFF Research Database (Denmark)

    Højgaard-Hansen, Kim; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2012-01-01

    The performance of wireless communication networks has been shown to have a strong location dependence. Measuring the performance while having accurate location information available makes it possible to generate performance maps. In this paper we propose a framework for the generation and use...... of such performance maps. We demonstrate how the framework can be used to reduce the retransmissions and to better utilise network resources when performing TCP-based file downloads in vehicular M2M communication scenarios. The approach works on top of a standard TCP stack hence has to map identified transmission...

  13. YottaYotta announces new world record set for TCP disk-to-disk bulk transfer

    CERN Multimedia

    2002-01-01

    The Yottabyte NetStorage(TM) Company, today announced a new world record for TCP disk-to-disk data transfer using the company's NetStorager(R) System. The record-breaking demonstration transferred 5 terabytes of data between Chicago, Il. to Vancouver, BC and Ottawa, ON, at a sustained average throughput of 11.1 gigabits per second. Peak throughput exceeded 11.6 gigabits per second, more than 15-times faster than previous records for TCP transfer from disk-to-disk (1 page).

  14. Road traffic injuries

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-guo 王正国

    2003-01-01

    @@ The appearance of cars has raised materialistic civilization and living standard to an unprecedented level. Today, it is hard to imagine how we human beings can live without cars.Yet, motor vehicles can cause a great number of deaths and injuries as well as considerable economic losses, which have constituted the global burden. Understanding of the occurrence and development of road traffic injuries will contribute to the prevention and control of crash and to the implementation of "everybody has the right to enjoy health" proposed by WHO.

  15. Inaccuracy in traffic forecasts

    DEFF Research Database (Denmark)

    Flyvbjerg, Bent; Holm, Mette K. Skamris; Buhl, Søren Ladegaard

    2006-01-01

    that forecasters generally do a poor job of estimating the demand for transportation infrastructure projects. The result is substantial downside financial and economic risk. Forecasts have not become more accurate over the 30-year period studied. If techniques and skills for arriving at accurate demand forecasts...... forecasting. Highly inaccurate traffic forecasts combined with large standard deviations translate into large financial and economic risks. But such risks are typically ignored or downplayed by planners and decision-makers, to the detriment of social and economic welfare. The paper presents the data...

  16. Performance Evaluation of DSDV and AODV Routing Protocols On The Basis Of TCP Variants in WSN and MANET

    Directory of Open Access Journals (Sweden)

    Shivangi Ranawat

    2014-01-01

    Full Text Available Transmission Control Protocol (TCP provides reliability to data transferring in all end-to-end data stream services on the internet. This protocol is utilized by major internet applications. TCP was originally created to handle the problem of network congestion collapse. This paper is prepared on the performance of different TCP variants to identify the best protocol variant for network expansion. In such context, a full comprehensive simulation environment is created for evaluating the comparative performance of TCP variants like TCP NewReno, SACK, FACK, RTCP and Vegas with the routing protocol AODV and DSDV in WSN and MANET. In this paper the overall performance of WSN and MANET is analyzed by comparing on the basis of Energy, End-to-End Delay, Throughput and Packet Delivery Ratio of the network.

  17. Advanced TCP Port Scan and Its Response%TCP端口的高级扫描及其响应

    Institute of Scientific and Technical Information of China (English)

    孙海峰

    2005-01-01

    TCP端口扫描分为TCP Connect()、TCP SYN、TCP ACK、TCP FIN和TCP NULL等扫描.利用TCP头部6个1位标志字段,向目标主机端口发送带特殊标志字段的数据包,分析目标主机响应数据包TCP头部的6个1位标志字段的内容,得目标主机的端口状态.其编程用VC6.0及Winsock原始套接字实现.

  18. Traffic flow impacts of adaptive cruise control deactivation and (Re)activation with cooperative driver behavior

    NARCIS (Netherlands)

    Klunder, G.; Li, M.; Minderhoud, M.

    2009-01-01

    In 2006 in the Netherlands, a field operational test was carried out to study the effect of adaptive cruise control (ACC) and lane departure warning on driver behavior and traffic flow in real traffic. To estimate the effect for larger penetration rates, simulations were needed. For a reliable impac

  19. The Research of Covert Channels Based on TCP/IP%基于TCP/IP协议的网络隐蔽通道研究

    Institute of Scientific and Technical Information of China (English)

    徐杰锋

    2003-01-01

    首先基于TCP/IP网络协议中的安全缺陷,给出了4种建立网络隐蔽通道的基本方法;然后,分析了当前主流防火墙以及入侵检测系统对建立这些隐蔽通道的影响;最后,讨论了网络隐蔽通道的防范措施.

  20. TCP/IP Protocol and Video Transfers on IP Multicast%TCP/IP协议和IP组播的视频传输

    Institute of Scientific and Technical Information of China (English)

    沈祖冀

    2001-01-01

    介绍介绍TCP/IP协议的有关内容。介绍IP组播,提出一种用IP组播的传输视频的解决方案和实现实例,此方案兼容现在的网络,有良好的视频信号传输效果。

  1. Real time traffic models, decision support for traffic management

    NARCIS (Netherlands)

    Wismans, L.J.J.; Romph, de E.; Friso, K.; Zantema, K.

    2014-01-01

    Reliable and accurate short-term traffic state prediction can improve the performance of real-time traffic management systems significantly. Using this short-time prediction based on current measurements delivered by advanced surveillance systems will support decision-making processes on various con

  2. Real Time Traffic Models, Decision Support for Traffic Management

    NARCIS (Netherlands)

    Wismans, L.; De Romph, E.; Friso, K.; Zantema, K.

    2014-01-01

    Reliable and accurate short-term traffic state prediction can improve the performance of real-time traffic management systems significantly. Using this short-time prediction based on current measurements delivered by advanced surveillance systems will support decision-making processes on various con

  3. Simulation of Traffic on Intersection After Change of Traffic Priority

    Directory of Open Access Journals (Sweden)

    Vladislav KŘIVDA

    2011-06-01

    Full Text Available This paper deals with problem of capacity calculation of intersection after change of traffic priority and with simulation of traffic using simulation software PTV VISSIM. This paper was prepared with financial support for project FRVŠ č. 2206/2011/F1/d “Innovation of Learning of Subjects from the Design of Urban Roads and Intersections”.

  4. Degradation characteristics, cell viability and host tissue responses of PDLLA-based scaffold with PRGD and β-TCP nanoparticles incorporation.

    Science.gov (United States)

    Yi, Jiling; Xiong, Feng; Li, Binbin; Chen, Heping; Yin, Yixia; Dai, Honglian; Li, Shipu

    2016-09-01

    This study is aimed to evaluate the degradation characteristics, cell viability and host tissue responses of PDLLA/PRGD/β-TCP (PRT) composite nerve scaffold, which was fabricated by poly(d, l-lactic acid) (PDLLA), RGD peptide(Gly-Arg-Gly-Asp-Tyr, GRGDY, abbreviated as RGD) modified poly-{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]}(PRGD) and β-tricalcium phosphate (β-TCP). The scaffolds' in vitro degradation behaviors were investigated in detail by analysing changes in weight loss, pH and morphology. Then, the 3-(4,5-dimethyl-2-thiazolyl) -2,5-diphenyl-2 -H-tetrazolium bromide (MTT) assay and cell live/dead assay were carried out to assess their cell viability. Moreover, in vivo degradation patterns and host inflammation responses were monitored by subcutaneous implantation of PRT scaffold in rats. Our data showed that, among the tested scaffolds, the PRT scaffold had the best buffering capacity (pH = 6.1-6.3) and fastest degradation rate (12.4%, 8 weeks) during in vitro study, which was contributed by the incorporation of β-TCP nanoparticles. After in vitro and in vivo degradation, the high porosity structure of PRT could be observed using scanning electron microscopy. Meanwhile, the PRT scaffold could significantly promote cell survival. In the PRT scaffold implantation region, less inflammatory cells (especially for neutrophil and lymphocyte) could be detected. These results indicated that the PRT composite scaffold had a good biodegradable property; it could improve cells survival and reduced the adverse host tissue inflammation responses.

  5. Understanding the influence of MgO and SrO binary doping on the mechanical and biological properties of beta-TCP ceramics.

    Science.gov (United States)

    Banerjee, Shashwat S; Tarafder, Solaiman; Davies, Neal M; Bandyopadhyay, Amit; Bose, Susmita

    2010-10-01

    The objective of this study was to evaluate the influence of MgO and SrO doping on the mechanical and biological properties of beta-tricalcium phosphate (beta-TCP). beta-TCP was doped with two different binary compositions, 0.25 and 1.0wt.% SrO along with 1.0wt.% MgO. MgO and SrO doping increased the beta phase stability at a sintering temperature of 1250 degrees C and marginally decreased the compressive strength of beta-TCP. An in vitro cell-material interaction study, using human fetal osteoblast cells (hFOB), indicated that doped beta-TCP was non-toxic, and MgO/SrO dopants improved cell attachment and growth. beta-TCP implants doped with 1.0wt.% MgO and 1.0wt.% SrO showed good in vivo biocompatibility when tested in male Sprague-Dawley rats for 16 weeks. Histomorphology analysis indicated that MgO/SrO-doped beta-TCP promoted more osteogenesis than pure beta-TCP. In vivo osteocalcin and type I collagen assay also revealed faster bone formation in rats with doped beta-TCP implant compared to rats with pure beta-TCP implant. Low Ca(2+) concentration in the urine of rats with doped beta-TCP implant confirmed slower degradation of MgO/SrO-doped beta-TCP than pure beta-TCP.

  6. 瓶颈网络TCP/主动队列管理模型及仿真%TCP/Active Queue Management Model and Simulation for Bottleneck Networks

    Institute of Scientific and Technical Information of China (English)

    曹振臻; 肖扬; 迟彩霞

    2009-01-01

    提出了一种基于离散时间Markov链的时延闭环反馈TCP/AQM(Active Queue Management)模型,并得到其稳态分布.通过以环路时延为单位,将系统时间分割成长度不同的时隙,分析每个时隙内TCP发送端发送窗口模型和瓶颈路由器队列模型.通过结合相邻时隙的参数,提出了TCP/AQM整体分析模型.该模型可以估计路由器的队列平均长度和丢包率、TCP发送端的平均发送窗口值,因此可以用于分析AQM算法性能以及给新算法的设计提供理论支持.通过在Matlab实施该模型与NS2仿真结果作比较,证实了该模型在模拟时延闭环反馈的TCP/RED系统的有效性.

  7. Carrying Capacity:An Overview

    Institute of Scientific and Technical Information of China (English)

    Chen Shaofeng

    2004-01-01

    The concept of carrying capacity is derived from ecology, with widespread contentions of its theoretical connotations and applications in the international academic community, especially the impact of human activities on the environment.Disputes on carrying capacity have been occurring not only among biologists and ecologists, but also among mainstream economists. Based on their efforts,the author makes an attempt to describe its origin,connotations, problems, measurement, and at the same time note the latest international progress in this field.

  8. Environmental stress model for evaluation of vessel traffic in ports and waterways

    Institute of Scientific and Technical Information of China (English)

    HU Zhiwu; CHEN Weijiong; INOUE K

    2005-01-01

    Environmental stress model is proposed as an effective tool to the analysis and evaluation of navigational safety in ports and waterways. Marine traffic simulations are carried out in a virtual port area with various arrangements and conditions. Calculations of stress values and traffic volume criteria are illustrated. The simulation results provide a valuable hint for safety management of vessel traffic. The model provides quantitative information and helps administrators in decision making to achieve desired safety level and improve the efficiency of vessel traffic in ports and waterways.

  9. ANALYSIS OF TRAFFIC CONDITIONS IN URBAN THOROUGHFARES

    OpenAIRE

    Kovalenko, L.; Urdzik, S.

    2006-01-01

    Results of experimental investigations into descriptions of traffic flows in urban thoroughfares have been considered. Dependencies between traffic speed, density and intensity for various traffic conditions have been offered.

  10. Multimedia Traffic Routing in Multilayer WDM Networks

    CERN Document Server

    Amphawan, Angela; Hasan, Hassanuddin

    2012-01-01

    The advent of real-time multimedia services over the Internet has stimulated new technologies for expanding the information carrying capacity of optical network backbones. Multilayer wavelength division multiplexing (WDM) packet switching is an emerging technology for increasing the bandwidth of optical networks. Two algorithms for the routing of the multimedia traffic flows were applied: (i) Capacitated Shortest Path First (CSPF) routing, which minimizes the distance of each flow linking the given source and destination nodes and satisfying capacity constraints; and (ii) Flow Deviation Algorithm (FDA) routing, which minimizes the network?wide average packet delay.

  11. Probabilistic description of traffic flow

    Science.gov (United States)

    Mahnke, R.; Kaupužs, J.; Lubashevsky, I.

    2005-03-01

    A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster consistent with the empirical observations in real traffic. The emphasis is put on the analogy with first-order phase transitions and nucleation phenomena in physical systems like supersaturated vapour. The results are summarized in the flux-density relation, the so-called fundamental diagram of traffic flow, and compared with empirical data. Different regimes of traffic flow are discussed: free flow, congested mode as stop-and-go regime, and heavy viscous traffic. The traffic breakdown is studied based on the master equation as well as the Fokker-Planck approximation to calculate mean first passage times or escape rates. Generalizations are developed to allow for on-ramp effects. The calculated flux-density relation and characteristic breakdown times coincide with empirical data measured on highways. Finally, a brief summary of the stochastic cellular automata approach is given.

  12. Reports on internet traffic statistics

    NARCIS (Netherlands)

    Hoogesteger, Martijn; Oliveira Schmidt, de Ricardo; Sperotto, Anna; Pras, Aiko

    2013-01-01

    Internet traffic statistics can provide valuable information to network analysts and researchers about the way nowadays networks are used. In the past, such information was provided by Internet2 in a public website called Internet2 NetFlow: Weekly Reports. The website reported traffic statistics fro

  13. Traffic Light Controller Using Fpga

    Directory of Open Access Journals (Sweden)

    D.Bhavana

    2015-04-01

    Full Text Available The traffic light sequence works on the specific switching of Red, Green and Yellow lights in a particular way with stipulated time form. The normal function of traffic lights requires sophisticated control and coordination to ensure that traffic moves as smoothly and safely as possible and that pedestrians are protected when they cross the roads [1] .This Traffic Light sequence is generated using a specific switching mechanism which will help to control a traffic light system on a road in a specified sequence. This paper focuses on the fact that the traffic lights can be varied in the day and night mode depending on the intensity of the traffic. It plays a vital role in supervising and running the metropolitan traffic and evade the possibilities of any unfortunate mishaps happening in and around the cities. It is a sequential machine to be scrutinized as per the requirements and programmed through a multistep development process. The methods that are used in this project are proposing the circuit, write a code, simulate, synthesis and implement on the hardware [8] . In this project, XILINX Software was chosen to devise a schematic using schematic edit, write a code using Verilog HDL (Hardware Description Language text editor and implements the circuit on Programmable Logic Device [PLD].The system has been successfully tested and implemented in hardware using Nexys 2 Digilent FPGA.

  14. Traffic Perception in Eskişehir Province

    Science.gov (United States)

    Karacasu, Murat; Altin, Arzu Yavuz; Ergül, Bariş; Berkhan Akalin, Kadir

    2016-10-01

    With the rapid growth of the world population that is becoming increasingly the use of motor vehicles. Also, due to technological advances that have become more accessible to a case having a motor vehicle. However, these developments have led to the emergence of some problems. Especially, highways of serious accidents occurred in transportation, to investigate measures that can be taken and identification of the problem is an important issue in Turkey. First, you need to identify the individual's perception of traffic. This process is important to identify gaps in the application. This study was planned and carried out in order to measure the traffic perceptions of living in Eskisehir Province. For this purpose, a questionnaire aimed at determining demographic and socio-economic characteristics and attitudes of the individual's perception of traffic was prepared. Data sets were analysed by factor analysis known as one of the most known multivariate statistical analysis techniques. The result of analysis obtained over the dimensions, traffic perceptions of individual's in Eşkisehir Province modelled. Looking for solutions for the traffic problem in institutions of the Eşkisehir Province has obtained a series of results that could benefit in creating attitudes and behaviours about traffic.

  15. Web traffic and firm performance

    DEFF Research Database (Denmark)

    Farooq, Omar; Aguenaou, Samir

    2013-01-01

    into better firm performance? This paper aims to answer these questions by documenting a positive relationship between the extent of web-traffic and firm performance in the MENA region during the 2010. We argue that higher web-traffic lowers the agency problems in firms by disseminating more information...... to stock market participants. Consequently, lower agency problems translate into better performance. Furthermore, we also show that agency reducing role of web-traffic is more pronounced in regimes where information environment is already bad. For example, our results show stronger impact of web......-traffic on firm performance in civil law countries, firms with concentrated ownership, and firms with more intangible assets. All of these groups are characterized by higher agency problems. Our results, therefore, indicate that web-traffic can play a substitute for traditional governance mechanisms in the MENA...

  16. Specific surface area effect on adsorption of chlorpyrifos and TCP by soils and modeling

    Science.gov (United States)

    The adsorption of chlorpyrifos and TCP (3,5,6, trichloro-2-pyridinol) was determined in four soils (Mollisol, Inceptisol, Entisol, Alfisol) having different specific surface areas (19–84 m2/g) but rather similar organic matter content (2.4–3.5%). Adsorption isotherms were derived from batch equilibr...

  17. Performance of TCP-friendly streaming sessions in the presence of heavy-tailed elastic flows

    NARCIS (Netherlands)

    Bekker, R.; Borst, S.C.; Núñez Queija, R.

    2005-01-01

    We consider a fixed number of streaming sessions which share a bottleneck link with a dynamic population of elastic flows. Motivated by extensive measurement studies, we assume that the sizes of the elastic flows exhibit heavy-tailed characteristics. The elastic flows are TCP-controlled, while the t

  18. Truncated power control for improving TCP/IP performance over CDMA wireless links

    DEFF Research Database (Denmark)

    Cianca, Ernestina; Prasad, Ramjee; De Sanctis, Mauro

    2005-01-01

    The issue of the performance degradation of transmission control protocol/Internet Protocol (TCP/IP) over wireless links due to the presence of noncongestion-related packet losses has been addressed with a physical layer approach. The effectiveness of automatic repeat request techniques in enhanc...

  19. A Simulation Study on the Throughput Performance of TCP over Wireless Fading Channel

    Institute of Scientific and Technical Information of China (English)

    YAO Ling; JI Hong; YUE Guang-xin

    2004-01-01

    Using Markov model and the network simulator-NS, this paper studies the TCP throughput performance in wireless fading channel where the packets losses are always caused by high and burst errors. The results show that the burstiness in packet errors caused by slow multipath fading benefits Reno compared to i.i.d packet errors.

  20. CNoA: Challenging Number Approach for uncovering TCP SYN flooding using SYN spoofing attack

    CERN Document Server

    Kavisankar, L

    2011-01-01

    The challenging number is used for the detection of Spoofing attack. The IP Spoofing is considered to be one of the potentially brutal attack which acts as a tool for the DDoS attack which is considered to be a major threat among security problems in today's internet. These kinds of attack are extremely severe. They bring down business of company drastically. DDoS attack can easily exhaust the computing and communication resources of its victim within a short period of time. There are attacks exploiting some vulnerability or implementation bug in the software implementation of a service to bring that down and some attacks will use all the available resources at the target machine. This deals on attacks that consume all the bandwidth available to the victim machine. While concentrating on the bandwidth attack the TCP SYN flood is the more prominent attack. TCP/IP protocol suite is the most widely used protocol suite for data communication. The TCP SYN flood works by exhausting the TCP connection queue of the h...

  1. Delay Prediction for Real-Time Video Adaptive Transmisson over TCP

    Directory of Open Access Journals (Sweden)

    Yonghua Xiong

    2010-06-01

    Full Text Available Real-time multimedia streaming applications are increasingly using TCP instead of UCP as underlying transport protocol, however the great end-to-end delays are the major factor to influence the quality of streaming across the Internet using TCP. In this paper, we point the requirement for transmitting real-time video with acceptable playing performance via TCP and present a stochastic prediction model which can predict the sending-delays of video frames.  Based on the prediction model, we propose a real-time video adaptive transmission scheme which can dynamically adjust video frame rate and playout buffer size according to available network bandwidth. The scheme does not require any modifications to the network infrastructure or TCP protocol stack and only wants to measure some parameters including video frame size, loss ratio, congestion windows size, RTT and RTO time before video frames are sent. The performance of proposed prediction model and adaptive scheme are evaluated through extensive simulations using the NS-2 simulator.

  2. Improving TCP Performance over Wireless Ad Hoc Networks with Busy Tone Assisted Scheme

    Directory of Open Access Journals (Sweden)

    Cai Lin

    2006-01-01

    Full Text Available It is well known that transmission control protocol (TCP performance degrades severely in IEEE 802.11-based wireless ad hoc networks. We first identify two critical issues leading to the TCP performance degradation: (1 unreliable broadcast, since broadcast frames are transmitted without the request-to-send and clear-to-send (RTS/CTS dialog and Data/ACK handshake, so they are vulnerable to the hidden terminal problem; and (2 false link failure which occurs when a node cannot successfully transmit data temporarily due to medium contention. We then propose a scheme to use a narrow-bandwidth, out-of-band busy tone channel to make reservation for broadcast and link error detection frames only. The proposed scheme is simple and power efficient, because only the sender needs to transmit two short messages in the busy tone channel before sending broadcast or link error detection frames in the data channel. Analytical results show that the proposed scheme can dramatically reduce the collision probability of broadcast and link error detection frames. Extensive simulations with different network topologies further demonstrate that the proposed scheme can improve TCP throughput by 23% to 150%, depending on user mobility, and effectively enhance both short-term and long-term fairness among coexisting TCP flows in multihop wireless ad hoc networks.

  3. TCP Transcription Factors at the Interface between Environmental Challenges and the Plant's Growth Responses.

    Science.gov (United States)

    Danisman, Selahattin

    2016-01-01

    Plants are sessile and as such their reactions to environmental challenges differ from those of mobile organisms. Many adaptions involve growth responses and hence, growth regulation is one of the most crucial biological processes for plant survival and fitness. The plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, PCF1 (TCP) transcription factor family is involved in plant development from cradle to grave, i.e., from seed germination throughout vegetative development until the formation of flowers and fruits. TCP transcription factors have an evolutionary conserved role as regulators in a variety of plant species, including orchids, tomatoes, peas, poplar, cotton, rice and the model plant Arabidopsis. Early TCP research focused on the regulatory functions of TCPs in the development of diverse organs via the cell cycle. Later research uncovered that TCP transcription factors are not static developmental regulators but crucial growth regulators that translate diverse endogenous and environmental signals into growth responses best fitted to ensure plant fitness and health. I will recapitulate the research on TCPs in this review focusing on two topics: the discovery of TCPs and the elucidation of their evolutionarily conserved roles across the plant kingdom, and the variety of signals, both endogenous (circadian clock, plant hormones) and environmental (pathogens, light, nutrients), TCPs respond to in the course of their developmental roles.

  4. Securing TCP/IP and Dial-up Access to Administrative Data.

    Science.gov (United States)

    Conrad, L. Dean

    1992-01-01

    This article describes Arizona State University's solution to security risk inherent in general access systems such as TCP/IP (Transmission Control Protocol/INTERNET Protocol). Advantages and disadvantages of various options are compared, and the process of selecting a log-on authentication approach involving generation of a different password at…

  5. MultiNet TCP/P/IP for VAX/VMS update

    Science.gov (United States)

    Vance, L. Stuart

    1991-01-01

    Outlines of device support; DECnet interoperability; installation; MultiNet services; domain name server; Telnet; FTP; SMTP; DECwindows over TCP/IP; BSD r services; remote printing; RPC services and NFS server; NFS client; netcontrol; diagnostics; programming support; and MultiNet features are presented in viewgraph format.

  6. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering.

    Science.gov (United States)

    Ardjomandi, N; Huth, J; Stamov, D R; Henrich, A; Klein, C; Wendel, H-P; Reinert, S; Alexander, D

    2016-10-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs.

  7. A multiple time-scale model for TCP bandwidth sharing under user heterogeneity

    NARCIS (Netherlands)

    Abendroth, D.; Berg, J.L. van den; Mandjes, M.

    2005-01-01

    Building on the vast body of existing TCP models, we develop a novel versatile model that explicitly captures user heterogeneity, and takes into consideration dynamics at both the packet level and the flow level. It is described how the resulting multiple time-scale model can be numerically evaluate

  8. TCP Transcription Factors at the Interface between Environmental Challenges and the Plant’s Growth Responses

    Science.gov (United States)

    Danisman, Selahattin

    2016-01-01

    Plants are sessile and as such their reactions to environmental challenges differ from those of mobile organisms. Many adaptions involve growth responses and hence, growth regulation is one of the most crucial biological processes for plant survival and fitness. The plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, PCF1 (TCP) transcription factor family is involved in plant development from cradle to grave, i.e., from seed germination throughout vegetative development until the formation of flowers and fruits. TCP transcription factors have an evolutionary conserved role as regulators in a variety of plant species, including orchids, tomatoes, peas, poplar, cotton, rice and the model plant Arabidopsis. Early TCP research focused on the regulatory functions of TCPs in the development of diverse organs via the cell cycle. Later research uncovered that TCP transcription factors are not static developmental regulators but crucial growth regulators that translate diverse endogenous and environmental signals into growth responses best fitted to ensure plant fitness and health. I will recapitulate the research on TCPs in this review focusing on two topics: the discovery of TCPs and the elucidation of their evolutionarily conserved roles across the plant kingdom, and the variety of signals, both endogenous (circadian clock, plant hormones) and environmental (pathogens, light, nutrients), TCPs respond to in the course of their developmental roles. PMID:28066483

  9. ComboCoding: Combined intra-/inter-flow network coding for TCP over disruptive MANETs

    Directory of Open Access Journals (Sweden)

    Chien-Chia Chen

    2011-07-01

    Full Text Available TCP over wireless networks is challenging due to random losses and ACK interference. Although network coding schemes have been proposed to improve TCP robustness against extreme random losses, a critical problem still remains of DATA–ACK interference. To address this issue, we use inter-flow coding between DATA and ACK to reduce the number of transmissions among nodes. In addition, we also utilize a “pipeline” random linear coding scheme with adaptive redundancy to overcome high packet loss over unreliable links. The resulting coding scheme, ComboCoding, combines intra-flow and inter-flow coding to provide robust TCP transmission in disruptive wireless networks. The main contributions of our scheme are twofold; the efficient combination of random linear coding and XOR coding on bi-directional streams (DATA and ACK, and the novel redundancy control scheme that adapts to time-varying and space-varying link loss. The adaptive ComboCoding was tested on a variable hop string topology with unstable links and on a multipath MANET with dynamic topology. Simulation results show that TCP with ComboCoding delivers higher throughput than with other coding options in high loss and mobile scenarios, while introducing minimal overhead in normal operation.

  10. Regulated intramembrane proteolysis of the virulence activator TcpP in Vibrio cholerae is initiated by the tail-specific protease (Tsp).

    Science.gov (United States)

    Teoh, Wei Ping; Matson, Jyl S; DiRita, Victor J

    2015-09-01

    Vibrio cholerae uses a multiprotein transcriptional regulatory cascade to control expression of virulence factors cholera toxin and toxin-co-regulated pilus. Two proteins in this cascade are ToxR and TcpP - unusual membrane-localized transcription factors with relatively undefined periplasmic domains and transcription activator cytoplasmic domains. TcpP and ToxR function with each other and two other membrane-localized proteins, TcpH and ToxS, to activate transcription of toxT, encoding the direct activator of toxin and pilus genes. Under some conditions, TcpP is degraded in a two-step proteolytic pathway known as regulated intramembrane proteolysis (RIP), thereby inactivating the cascade. The second step in this proteolytic pathway involves the zinc metalloprotease YaeL; V. cholerae cells lacking YaeL accumulate a truncated yet active form of TcpP termed TcpP*. We hypothesized that a protease acting prior to YaeL degrades TcpP to TcpP*, which is the substrate of YaeL. In this study, we demonstrate that a C-terminal protease called Tsp degrades TcpP to form TcpP*, which is then acted upon by YaeL. We present evidence that TcpH and Tsp serve to protect full-length TcpP from spurious proteolysis by YaeL. Cleavage by Tsp occurs in the periplasmic domain of TcpP and requires residues TcpPA172 and TcpPI174 for wild-type activity.

  11. Energy Saving: Scaling Network Energy Efficiency Faster than Traffic Growth

    NARCIS (Netherlands)

    Chen, Y.; Blume, O.; Gati, A.; Capone, A.; Wu, C.-E.; Barth, U.; Marzetta, T.; Zhang, H.; Xu, S.

    2013-01-01

    As the mobile traffic is expected to continue its exponential growth in the near future, energy efficiency has gradually become a must criterion for wireless network design. Three fundamental questions need to be answered before the detailed design could be carried out, namely what energy efficiency

  12. An Approach to Traffic Scenario Analysis, Generation and Evaluation

    NARCIS (Netherlands)

    Chen, Y.; Van Zuylen, H.J.

    2014-01-01

    Start taking a few most applied scenarios from a traffic control centre, analysing each component and structure of the whole, and evaluating the impact of each component and some typical combinations, based on available monitoring systems. Carrying on such initial research on best practices, we buil

  13. Traffic information computing platform for big data

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Zongtao, E-mail: ztduan@chd.edu.cn; Li, Ying, E-mail: ztduan@chd.edu.cn; Zheng, Xibin, E-mail: ztduan@chd.edu.cn; Liu, Yan, E-mail: ztduan@chd.edu.cn; Dai, Jiting, E-mail: ztduan@chd.edu.cn; Kang, Jun, E-mail: ztduan@chd.edu.cn [Chang' an University School of Information Engineering, Xi' an, China and Shaanxi Engineering and Technical Research Center for Road and Traffic Detection, Xi' an (China)

    2014-10-06

    Big data environment create data conditions for improving the quality of traffic information service. The target of this article is to construct a traffic information computing platform for big data environment. Through in-depth analysis the connotation and technology characteristics of big data and traffic information service, a distributed traffic atomic information computing platform architecture is proposed. Under the big data environment, this type of traffic atomic information computing architecture helps to guarantee the traffic safety and efficient operation, more intelligent and personalized traffic information service can be used for the traffic information users.

  14. Evaluation of The Impacts of VMS on Traffic Performance Measures in An Urban Area in Indonesia

    Directory of Open Access Journals (Sweden)

    A. Caroline Sutandi

    2008-01-01

    Full Text Available Variable Message Sign (VMS is especially recommended for congested flow conditions. The aim of this study is to investigate how drivers in a large city in a developing country with many specific geometric and traffic conditions and also specific driver behaviour, use VMS in aid of choosing route for their inter-city trips. Furthermore, to explore the impact of the use of the information on increasing traffic performance measures. A case study was carried out in Bandung, Indonesia. Microscopic traffic simulations were used in this study to evaluate traffic performance measures. The results of the evaluation found that VMS has insignificant impact on drivers’ route choice behaviour. The results indicated that drivers in Bandung rely much on their experience of traffic conditions commonly occur in the city and demonstrated that VMS has no significant impact to increase traffic performance, but has better impact on the roads with higher number of alternative roads.

  15. GIS-based methods for establishing the datafoundation for traffic models

    DEFF Research Database (Denmark)

    Nielsen, Otto Anker

    1997-01-01

    Traffic models demand large amounts of data - some of which are: Traffic network topology, traffic network data, zone-data and trip matrices. GIS is a natural tool for handling most of these data as it can ease the work process and improve the quality control. However, traffic models demand a com......-plex topology not very well covered by the traditional GIS-topology. The paper describes a number of applications where ARC/INFO and ArcView have been used to automate the process of building a traffic network topology. The methodology has been used on a number of full-scale models, from medium sized urban...... at network level.Some of these tasks would have demanded an overwhelming work effort to carry through with tra-ditional non-GIS based approaches. In addition, the paper discusses how the GIS can interact with the traffic model algorithms (typically external applications). Finally, needs for further...

  16. Rapid Protoyping Software for Developing Next-Generation Air Traffic Management Algorithms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Research on next-generation air traffic control systems are being conducted at several laboratories. Most of this work is being carried out using custom software. In...

  17. The Influences of Composition and Formula on α-TCP/β-TCP Phosphate Cement's Properties%α-TCP/β-TCP骨水泥组成及配比对性能的影响

    Institute of Scientific and Technical Information of China (English)

    史雪婷; 徐立新; 石宗利

    2006-01-01

    通过对α-TCP体系骨水泥固相粉末配方的优化,研究了不同重量比α-TCP/β-TCP粉末对两相骨水泥凝固时间和抗压强度的影响.结果表明粉末含有β-TCP时,骨水泥凝固时间更适合临床塑型,且β-TCP含量为20%时,抗压强度达52.98 MPa.

  18. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ardjomandi, N.; Huth, J. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Stamov, D.R. [JPK Instruments AG, Berlin (Germany); Henrich, A. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Klein, C. [Dental Practice Zahngesundheit Waiblingen, Waiblingen (Germany); Wendel, H.-P. [Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Tübingen (Germany); Reinert, S. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Alexander, D., E-mail: dorothea.alexander@med.uni-tuebingen.de [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany)

    2016-10-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs. - Highlights: • Covalent binding of aptamer 74 on PLGA-coated β-tricalcium phosphate constructs. • AFM analysis of rupture forces between aptamer 74 and jaw periosteal cells. • Analysis of jaw periosteal cell functions on aptamer coated β-TCP constructs.

  19. Proliferation and osteogenic differentiation of human periodontal ligament cells on akermanite and β-TCP bioceramics

    Directory of Open Access Journals (Sweden)

    L Xia

    2011-07-01

    Full Text Available The purpose of this study was to investigate the effects of akermanite as compared to β-TCP on attachment, proliferation, and osteogenic differentiation of human periodontal ligament cells (hPDLCs. Scanning electron microscopy (SEM and actin filament labeling were used to reveal attachment and growth of hPDLCs seeded on β-TCP and akermanite ceramic. Cell proliferation was tested by lactic acid production and MTT analysis, while osteogenic differentiation was assayed by alkaline phosphatase (ALP expression and real-time polymerase chain reaction (PCR analysis on markers of osteopontin (OPN, dentin matrix acidic phosphoprotein-1 (DMP-1, and osteocalcin (OCN, and further detected by enzyme-linked immunosorbent analysis (ELISA analysis for OCN expression. Besides, the ions released from akermanite and their effect on hPDLCs was also measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES, MTT analysis, ALP expression and real-time PCR analysis. hPDLCs attached well on both ceramics, but showed better spreading on akermanite. hPDLCs proliferated more rapidly on akermanite than β-TCP. Importantly, osteogenic differentiation of hPDLCs was enhanced on akermanite compared to β-TCP. Besides, Ca, Mg and Si ions were released from akermanite, while only Ca ions were released from β-TCP. Moreover, more pronounced proliferation and higher osteogenic gene expression for hPDLCs cultured with akermanite extract were detected as compared to cells cultured on akermanite. Therefore, akermanite ceramic showed an enhanced effect on proliferation and osteogenic differentiation of hPDLCs, which might be attributed to the release of ions containing Ca, Mg and Si from the material. It is suggested that akermanite ceramics may serve as a potential material for periodontal bone regeneration.

  20. Misato Controls Mitotic Microtubule Generation by Stabilizing the TCP-1 Tubulin Chaperone Complex [corrected].

    Science.gov (United States)

    Palumbo, Valeria; Pellacani, Claudia; Heesom, Kate J; Rogala, Kacper B; Deane, Charlotte M; Mottier-Pavie, Violaine; Gatti, Maurizio; Bonaccorsi, Silvia; Wakefield, James G

    2015-06-29

    Mitotic spindles are primarily composed of microtubules (MTs), generated by polymerization of α- and β-Tubulin hetero-dimers. Tubulins undergo a series of protein folding and post-translational modifications in order to fulfill their functions. Defects in Tubulin polymerization dramatically affect spindle formation and disrupt chromosome segregation. We recently described a role for the product of the conserved misato (mst) gene in regulating mitotic MT generation in flies, but the molecular function of Mst remains unknown. Here, we use affinity purification mass spectrometry (AP-MS) to identify interacting partners of Mst in the Drosophila embryo. We demonstrate that Mst associates stoichiometrically with the hetero-octameric Tubulin Chaperone Protein-1 (TCP-1) complex, with the hetero-hexameric Tubulin Prefoldin complex, and with proteins having conserved roles in generating MT-competent Tubulin. We show that RNAi-mediated in vivo depletion of any TCP-1 subunit phenocopies the effects of mutations in mst or the Prefoldin-encoding gene merry-go-round (mgr), leading to monopolar and disorganized mitotic spindles containing few MTs. Crucially, we demonstrate that Mst, but not Mgr, is required for TCP-1 complex stability and that both the efficiency of Tubulin polymerization and Tubulin stability are drastically compromised in mst mutants. Moreover, our structural bioinformatic analyses indicate that Mst resembles the three-dimensional structure of Tubulin monomers and might therefore occupy the TCP-1 complex central cavity. Collectively, our results suggest that Mst acts as a co-factor of the TCP-1 complex, playing an essential role in the Tubulin-folding processes required for proper assembly of spindle MTs.