File Transmission Research Articles

Investigating a file transfer protocol using CSP and B

In this paper a file transmission protocol specification is developed using the combination of two formal methods: CSP and B. The aim is to demonstrate that it is possible to integrate two well established formal methods whilst maintaining their individual advantages. We discuss how to compositionally verify the specification and ensure that it preserves some abstract properties. We also discuss how the structure of the specification follows a particular style which may be generally applicable when modelling other protocols using this combination .

Video Data Transmission Protocol "SVFTP" Using Multiple TCP Connections and Its Application

This paper presents a novel data transmission protocol SVFTP, which enables high-speed and error-free video data transmission over IP networks. A video transmission system based on SVFTP is also presented. While conventional protocols are designed for file transmission, SVFTP focuses on video data as a continuous media. In order to fit a flexible video transmission system, SVFTP achieves higher throughput on the long distance link as well as transmission interruption/resumption and progressive download and play back. In addition, a rate shaping mechanism for SVFTP is introduced in order to control greediness and burst traffic of multiple-TCP sessions. Laboratory and field transmission experiments show that SVFTP achieves high performance and functionality.

Sequence-switch coding for low-power data transmission

Reducing the power dissipated by buses becomes one of the most important elements in low-power VLSI design. A new coding scheme called sequence-switch coding (SSC) is proposed in this paper. It is a general-purpose coding scheme that employs the sequence of data in reducing the number of transitions on buses. A simple switching algorithm is presented to show the feasibility of SSC. According to simulations, this algorithm reduces around 10% of bus transitions in the transmission of benchmark files. SSC can be used for burst data transfer in any application. In particular, it is suitable for internet and multimedia applications that have stream-type data transfer pattern.

Webcasting Business Models of Clicks-and-Bricks and Pure-Play Media: A Comparative Study of Leading Webcasters in South Korea and the United States

This article identifies the business models of leading Webcasters in the United States and South Korea and proposes a cross-cultural framework to analyze the determinants of business models. The file transmission methods, content strategies, and revenue sources of clicks-and-bricks and pure-play Webcasters were compared in the study. After analyzing the business practices of 48 leading Webcasters--using a content analysis of their sites--we found that the content aggregator model and the branded content model are the 2 most commonly used business models of leading Webcasters in the United States and South Korea. Although clicks-and-bricks and pure-play Webcasters in both countries have a similar reliance on advertising as their major source of revenue, they employ different content strategies to their own media's advantages. Korean Webcasters are more likely to use pay-per-view as a revenue source than U.S. Webcasters.

Long‐range dependence and performance in telecom networks

AbstractTelecommunications systems have recently undergone significant innovations. These call for suitable statistical models that can properly describe the behaviour of the input traffic in a network. Here we use fractional Brownian motion (FBM) to model cumulative traffic network, thus taking into account the possible presence of long‐range dependence in the data. A Bayesian approach is devised in such a way that we are able to: (a) estimate the Hurst parameter H of the FBM; (b) estimate the overflow probability which is a parameter measuring the quality of service of a network: (c) develop a test for comparing the null hypothesis of long‐range dependence in the data versus the alternative of short‐range dependence. In order to achieve these inferential results, we elaborate an MCMC sampling scheme whose output enables us to obtain an approximation of the quantities of interest. An application to three real datasets, corresponding to three different levels of traffic, is finally considered. Copyright © 2004 John Wiley & Sons, Ltd.

The distribution of file transmission duration in the web

AbstractIt is well known that the distribution of files transmission duration in the Web is heavy‐tailed (A practical guide to Heavy Tails: Statistical Techniques and Application. Birkhauser: Boston, 1998; 3–26). This paper attempts to understand the reasons for this phenomenon by isolating the three major factors influencing the transmission duration: file size, network conditions and server load.We present evidence that the transmission‐duration distribution (TDD) of the same file from the same server to the same client in the Web is Pareto and therefore heavy tailed. Furthermore, text files transmission delay for a specific client/server pair is not significantly affected by the file sizes: all files transmitted from the same server to the same client have very similar transmission duration distributions, regardless of their size.We use simulations to estimate the impact of network conditions and server load on the TDD. When the server and the client are on the same local network, the TDD of each file is usually Pareto as well (for server files and client requests that are distributed in a realistic way).By examining a wide‐area network situation, we conclude that the network conditions do not have a major influence on the heavy‐tailed behaviour of TDD. In contrast, the server load is shown to have a significant impact on the high variability of this distribution. Copyright © 2004 John Wiley & Sons, Ltd.

Dynamic parameter adjustment for available-bandwidth estimation of TCP in wired–wireless networks

With the extensive spread of the Internet and mobile terminals, Internet access from a mobile terminal becomes more important than ever before. In the Internet, the transmission control protocol (TCP) is used as a standard data transport protocol; however, it is well known that TCP performance degrades in wired–wireless network environments. This is because TCP was designed originally for an exclusively wired network environment. In this paper, we propose a simple TCP algorithm for wired–wireless network environments by focusing on small-sized file document transmission. In the proposed algorithm, the available bandwidth of a network is well estimated with time intervals between consecutive ACKs. With these estimates, the congestion control in the proposed method adapts to the state of a wireless link and prevents throughput degradation. A simple filter is used for available bandwidth estimation and dynamic adjusting of a filter parameter according to the state of the wireless link, thus improving the throughput of small-sized file transmission. We compare the proposed algorithm with the existing TCP Reno and TCP Westwood by simulation and show that the proposed algorithm achieves better performance than these two TCP algorithms in wired–wireless network environments.

Requirements and referential software architecture for home server based inter-home multimedia collaboration services

This paper presents requirements and referential software architecture for home server based multimedia collaboration services. The architecture can be applied to home servers and mobile devices for collaborative works such as voice over Internet protocol, collaborative web browsing, file transmission, and instant messaging.

Field test results on JPEG∕text file transmission employing RZ SSB transceivers through HF radio channel

The author presents field test results on real-zero single-sideband (RZ SSB) technology carried out over a HF radio channel. The purpose of conducting field tests was to clarify whether the RZ SSB technology can be satisfactorily adapted for HF data communications. During the tests, bit error rate (BER) performances of the RZ SSB were investigated first with an ITU-T Recommendation V.29 modem with bit rates ranging from 2.4 kbit/s to 9.6 kbit/s. Successful results for BER performance led to JPEG/text file transmissions using a facsimile modem as well as the RZ SSB transceivers. Throughout testing, JPEG/text files were transmitted and received with perfect quality even through an HF simplex radio channel between two coastal stations approximately 2000 km apart after completion of normal transmission. Detailed reports on both JPEG/text files and BER transmission performance are given. In conclusion, it appears that the RZ SSB technology can certainly be adapted for HF data communication, and further it is proved that it is superior to conventional SSB technology.

Comparative study of file formats for image storage and transmission

Abstract. We present a comparative analysis of features such ascompression rate, image loss, sensitivity to resolution variation, etc.,for still image file formats in the most widespread use today forimage storage and transmission on computer networks. © 2004SPIE and IS&T. [DOI: 10.1117/1.1634591] 1 IntroductionNowadays, digital images are widely used in an extensivenumber of computer applications. Despite the fast growthof storage medium technologies, the use of images has be-come so popular that it always runs behind the greedy needfor resources. With the Internet, millions of web pages arebeing transmitted every moment and images are most oftheir content. More and more sophisticated image compres-sion algorithms are being continuously developed 1,2 and in-corporated into the ‘‘formats’’ of files, such as BMP, 3 PNG, 4,5 TIFF, 6 and JPEG, 7–9 among others. 10,11 The firstobjective of image compression schemes was to store im-ages in an efficient way, representing them in an accurateform and using as little space as possible. Today, however,due to the possibility of file transmission through computernetworks, a new aspect grows in importance—the way theimage is sent and the time elapsed in providing the observerenough elements for its recognition may be even more im-portant than the final size of the file. The correct election ofthe algorithm to be used for storage and/or transmissiondepends upon a series of factors, such as image nature,resolution, gamut ~number of colors used!, compression/decompression speed, how the algorithm decomposes im-ages, etc.This paper presents a comparative analysis betweencompression algorithms of widespread use today in com-mercial tools for storage and transmission. Images havebeen previously classified according to their nature~land-scapes, persons, objects, etc.!, with resolutions of 75, 100,150, 200, and 300 dpi. Several features have been analyzedaiming to identify points in which it could be establishedwhich algorithms are the most efficient for each type ofimage. The new graphic format JPEG2000

A SINGLE CHANNEL ON/OFF MODEL WITH TCP-LIKE CONTROL

We model behavior of a TCP-like source transmitting over a single channel to a server that processes work at a constant rate τ. Transmission by the source follows an on/off mechanism. When the overall load in the system is below a critical constant γ, transmission rates increase linearly but when the load exceeds γ, then transmission rates decrease geometrically fast. We study the system by means of an embedded Markov chain, which gives the buffer content at the start of transmissions. Attention is paid to the time necessary to transmit a file of size L and both the tail behavior and expectation of the distribution of file transmission time are considered.

File transmission over wireless fast fading downlink

The third-generation code division multiple access (3G CDMA) mobile communication networks are designed to transmit voice and data over wireless channels. Fundamental problems need to be solved for such mobile communication networks to operate efficiently. One of the problems is finding optimal scheduling algorithms for file transmission over the fading downlink channel from a base station to mobile users. Here, the problem is solved in the case of transmission of a given number of files. Optimal algorithms that minimize the delay and the transmission time are found. Also, specific nonoptimal algorithms are considered and compared numerically with the optimal ones. We consider a slotted downlink with channels to the mobile users that are dependent in the same slot but independent for different slots. Additionally, some generalizations are presented.

A fast chaotic cryptographic scheme with dynamic look-up table

We propose a fast chaotic cryptographic scheme based on iterating a logistic map. In particular, no random numbers need to be generated and the look-up table used in the cryptographic process is updated dynamically. Simulation results show that the proposed method leads to a substantial reduction in the encryption and decryption time. As a result, chaotic cryptography becomes more practical in the secure transmission of large multi-media files over public data communication network.

The usefulness of telemedicine for the detection of infection/inflammation at the point of care.

The objective of this study is to examine the possibility of using Telemedicine to diagnose the presence of the inflammatory response and to assess its intensity at the point of care. One drop of citrated peripheral venous blood from 15 patients with infection/inflammation and 15 controls were used to prepare the slides. Unstained pictures were analyzed using a microscope, video camera and image analyzer (INFLAMETTM, Biovision, Tel Aviv, Israel). The jpg-compressed images were transferred via telephone to a physician in a remote location. A significant correlation was noted between the white blood cell count and the number of leukocytes per square mm by image analysis (r = 0.67 p < 0.0001 n = 30), between the degree of leukocyte adhesiveness/aggregation and the concentration of C-reactive protein (r = 0.42 p = 0.02 n = 29) and between the degree of erythrocyte aggregation and either fibrinogen concentrations (r = 0.73 p < 0.0001) or erythrocyte sedimentation (r = 0.83, p < 0.0001). No problems occurred during file transmission and there were no transfer errors. Physicians can successfully estimate the presence of an inflammatory response and its intensity using a simple slide test, image analysis, and Telemedicine technology.

Transmission and Management of DICOM Files Based on Peer to Peer

Transmission and Management of DICOM Files Based on Peer to Peer

Local CD-ROM in interaction with HTML documents over the Internet

The internet and computer assisted learning have enhanced the possibilities of providing quality distance learning in dentistry. The use of multimedia material is an essential part of such distance learning courses. However the Internet technology available has limitations regarding transmission of large multimedia files. Therefore especially when addressing undergraduate students or geographically isolated professionals, large download times make distance learning unattractive. This problem was technically solved in a distance learning course for undergraduate students from all over Europe. The present communication describes a method to bypass the problem of transmitting large multimedia files by the use of a specially designed CD-ROM. This CD-ROM was run locally on the students' PC interacting with HTML documents sent over the Internet.

Faster analysis of forming problems through use of coarse mesh models for dies

Finite element analysis of bulk forming processes involves geometric checks for contact between objects. When only material flow is to be evaluated, representing dies with the fewest possible elements significantly reduces the time spent by the solver in geometric checks for contact. This paper describes a procedure to coarsen a mesh while retaining important geometric features. A compacted mesh model also results in (a) reduced memory usage, (b) smaller results file, (c) faster visualization, and, (d) faster transmission of files. Results from the finite element analysis of a forging process, performed with a commercial solver, are presented.

Design computer network by using powerline

In this paper, a powerline medium computer network system is introduced. By using the AC power supply line which already exist and a special physical interface communication networking among many computer stations can by done conveniently. Based on the analysis of powerline characteristics, the paper discusses the physical interface that is the key technologies connected with computer network. It includes coupled circuit and filter circuit which are the key link of isolating alternating current power and filtering the interfered noise. This system is designed according to CSMA network communication protocol and the high-layer protocol software is discussed in detail. Many experiments as screen conversations, disk files transmission and shared print have proved that the performance of the system is good, the data transmission is correct.

Optimization of a low-cost truly preemptive multitasking PC diagnostic workstation.

The Windows 95/NT operating systems (Microsoft Corp, Redmond, WA) currently provide the only low-cost truly preemptive multitasking environment and as such become an attractive diagnostic workstation platform. The purpose of this project is to test and optimize display station graphical user interface (GUI) actions previously designed on the pseudomultitasking Macintosh (Apple Computer, Cupertino, CA) platform, and image data transmission using time slicing/ dynamic prioritization assignment capabilities of the new Windows platform. A diagnostic workstation in the clinical environment must process two categories of events: user interaction with the GUI through keyboard/mouse input, and transmission of incoming data files. These processes contend for central processing units (CPU) time resulting in GUI "lockout" during image transmission or delay in transmission until GUI "quiet time." WinSockets and the Transmission Control Protocol/Internet Protocal (TCP/IP) communication protocol software (Microsoft) are implemented using dynamic priority timeslicing to ensure that GUI delays at the time of Digital Imaging and Communications in Medicine (DICOM) file transfer do not exceed 1/10 second. Assignment of thread priority does not translate into an absolute fixed percentage of CPU time. Therefore, the relationship between dynamic priority assignment by the processor, and the GUI and communication application threads will be more fully investigated to optimize CPU resource allocation. These issues will be tested using 10 MB/sec Ethernet and 100 MB/sec fast and wide Ethernet transmission. Preliminary results of typical clinical files (10 to 30 MB) over Ethernet show no visually perceptible interruption of the GUI, suggesting that the new Windows PC platform may be a viable diagnostic workstation option.

Performance evaluation of file transfer under multimedia environment in atm networks

AbstractVarious communications services are being provided over ATM networks, and among them, file transfer is considered to be an important service. In file transfer, cases in which immediacy with respect to the connection request of a call is not as strong as in voice and picture may also be considered. In addition, in band allocation necessary during the call setup time, the transmission rate may be established freely to a certain extent by a terminal.In view of the foregoing, in this article, performance of file transfer multiplexed with other traffic in ATM networks is evaluated considering the forementioned characteristics.First, the effects of the file transmission rate and the performance of the system maintaining the file transfer over a single channel are studied and then the performance over multichannels is evaluated. As a measure of these performances, the throughput, which is important in file transfer, also is evaluated using the call loss probability considered to be important from the viewpoint of the user.