Dissertations / Theses on the topic 'File transfer protocol'

Överföring eller mottagande av datorfiler är en syssla som de flesta av oss ägnar ossåt regelbundet i ett eller annat sammanhang, oavsett om det sker privat eller om detär arbetsrelaterat. File Transfer Protocol (FTP) är ett protokoll för just detta ändamålsom lanserades under tiden då persondatorer hade blivit allt vanligare i hemmetoch på arbetsplatsen. Sedan dess har flera andra protokoll introducerats och i dagslägetfinns det flertalet valmöjligheter tillgängliga, alla med sina unika såväl som gemensammaegenskaper. Simple Mail Transfer Protocol (SMTP) kompletterad medMIME-standarden är ett populärt alternativ till de renodlade filöverföringsprotokollenpå grund av användarnas bekantskap och tidigare erfarenheter med e-posttjänster.Att skicka och ta emot filer via e-post innebär dock vissa begränsningar samt att vissasäkerhetsaspekter måste tas i beaktande, i synnerhet för företagsanvändare som dagin och dag ut måste hantera känslig data. I denna uppsats har tre olika filöverföringsprotokoll(SFTP, SMTP och HTTP) utvärderats ur ett användarvänlighetsperspektivsåväl som ett säkerhetsperspektiv. Resultatet indikerar att HTTP(S) tillsammans meduttökningen WebDAV kan anses vara ett lämpligt alternativ för organisationer somsamtidigt är enkelt att använda. De övriga protokollen, SMTP och SFTP, har ocksåsina användningsområden där SFTP verkar vara mer tilltalande för avanceradeanvändare och där SMTP förblir ett gångbart alternativ för privat bruk av mindreavancerade användare under vissa förutsättningar.
Transferring and receiving computer files are something most of us do on a regularbasis whether it is for private purposes or if it is work related. FTP is a protocolused for this very purpose which was launched during a time when personal computerswere growing increasingly popular in both home and workplace environments.Since then, more protocols have been introduced and today there are a number ofoptions available bringing new and common features alike to the market. The SMTPprotocol, extended with the MIME standard, is currently a widely used alternative tothe pure file transfer protocols due to the user familiarity and past experiences withthese mail services. Sending and receiving files through e-mail does however implysome limitations together with the fact that some security aspects need to be takeninto consideration, particularly for company users handling sensitive data. In thisthesis, three different file transfer protocols (SMTP, SFTP and HTTP) have all beenevaluated in account of their user friendliness as well as their security features. Theresults indicate that HTTP(S) combined with the WebDAV extension can be considereda viable alternative for organizations due to its user friendliness and security.The remaining protocols, SMTP and SFTP, also have their uses where SFTP wouldseem to be an appealing option for advanced users and where SMTP remains a passablealternative for private usage by regular users under the right conditions.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Reliable delivery of data products is often required across space links. For example, a NASA mission will require reliable delivery of images produced by an on-board detector. Many missions have their own (unique) way of accomplishing this, requiring custom software. Many missions also require manual operations (e.g. the telemetry receiver software keeps track of what data is missing, and a person manually inputs the appropriate commands to request retransmissions). The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) specifically for this situation. CFDP is an international standard communication protocol that provides reliable delivery of data products. It is designed for use across space links. It will work well if run over the widely used CCSDS Telemetry and Telecommand protocols. However, it can be run over any protocol, and will work well as long as the underlying protocol delivers a reasonable portion of the data. The CFDP receiver will autonomously determine what data is missing, and request retransmissions as needed. The CFDP sender will autonomously perform the requested transmissions. When the entire data product is delivered, the CFDP receiver will let the CFDP sender know that the transaction has completed successfully. The result is that custom software becomes standard, and manual operations become autonomous. This paper will consider various ways of achieving reliable file delivery, explain why CFDP is the optimal choice for use over space links, explain how the core protocol works, and give some guidance on how to best utilize CFDP within various mission scenarios. It will also touch on additional features of CFDP, as well as other uses for CFDP (e.g. the loading of on-board memory and tables).

Denna uppsats behandlar ämnet filöverföring i ett nätverk. Fokus för arbetet har varit att undersöka MTU:ns inverkan på överföringshastigheten vid filöverföringar baserat på vilket protokoll som används och storleken på filerna som överförs. I arbetet har ett flertal experiment genomförts som syftat till att utreda detta, samt att finna vilket protokoll som överlag presterar bäst baserat på omständigheterna för överföringen. Olika filöverföringsprotokoll, fildistributionsprotokoll, MTU:er samt filstorlekar har testats för att finna vad som resulterar i högst överföringshastighet vid filöverföring över ett Ethernetnätverk. Resultaten visar på att en hög MTU uppnår högst överföringshastighet vid överföring av stora filer, men att en standard-MTU fungerar bättre för att överföra mycket små filer.
This report concerns the subject of file transfer. The focal point of the report is to study the effect that the MTU has on the speed of file transfers based on the protocol used and the size of the transferred files. During the course of the work, several experiments have been performed in order to determine this, as well as to find which protocol gives the overall best result based on the circumstances of the file transfers. Various file transfer protocols, file distribution protocols, MTUs and file sizes have been tested in order to find what results in the best file transfer speed over an Ethernet based network. The results show that a high MTU has the best performance when transferring large files, while a standard MTU gives better results for transferring very small files.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California
The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) to provide reliable delivery of files across space links. Space links are typically intermittent, requiring flexibility on the part of CFDP. Some aspects of that flexibility will be highlighted in this paper, which discusses the planned use of CFDP on the Global Precipitation Measurement (GPM) mission. The operational scenario for GPM involves reliable downlink of science data files at a high datarate (approximately 4 megabits per second) over a space link that is not only intermittent, but also one-way most of the time. This paper will describe how that scenario is easily handled by CFDP, despite the fact that reliable delivery requires a feedback loop.

Bibliography: leaves 128-135. Investigates the behaviour of TCP bulk file transfer application sessions in a broadband access environment. Introduces some concepts for evaluating network behaviour: a path instability parameter for analyzing different TCP connections; a minimum RTT delay and a minimum typical path for estimating path characteristics between a client and application servers.

This master thesis is mainly focused on the backup systems and describes each individual backup techniques in detail. Next main point of this thesis, is explaining functionality of IPv4 and FTP, which are closely related to the topic. Outcome is a backup application written in Java language, which is capable of backup files on FTP server or on local/ network storage area. Backup application also allows settings for automatic backup and restoring files from the storage area. Finally there was made a measurment, where were point out advantages and disadvantages of transfer mediums and where was practically shown a logic of creating the backup system. Goal was a creation of multiplatform backup application.

Different computer systems have their own ways of representing, storing and managing files. One approach to facilitate file transfers among systems in a heterogeneous networked environment is for each system to locally map files for transfer onto a virtual filestore (VFS). Conceptually, a virtual filestore provides a universal model for describing files and how they can be manipulated. The ISO File Transfer, Access and Management (FTAM) protocol offers one such virtual filestore model. This thesis reports on the prototype implementation of a useful subset of the ISO FTAM protocol for the UNIX 4.2 BSD¹ file system. We call this implementation ubcFTAM. UNIX files, ordinarily regarded as unstructured, can be endowed with some internal structure thereby allowing the transfer of selective portions of a file. Furthermore, the implementation offers several file attributes not supported by UNIX. ubcFTAM runs on several Sun Workstations² interconnected by a 10 Mbps Ethernet. Some performance data of ubcFTAM are also presented. This thesis also identifies several aspects of the specifications that are ambiguous or that are inadequate, warranting further studies. Resolutions for these issues are discussed. We hope this experience will be useful to others planning to implement FTAM for UNIX systems. ¹UNIX is a registered trademark of American Telephone and Telegraph Bell Laboratories. BSD denotes Berkeley Standard Distribution ²SUN Workstation is a trademark of Sun Microsystems, Inc.
Science, Faculty of
Computer Science, Department of
Graduate

Dissertation (Ph.D.) -- Worcester Polytechnic Institute.
Keywords: streaming media; streaming transport protocol; active queue management (AQM); Internet congestion control. Includes bibliographical references (p. 236-248).

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This thesis is intended to look into the FTP (File Transfer Protocol) system on the News Broadcasting production from stations belonging to Rede Amazônica (TV Amazonas, TV Rondônia, TV Acre, TV Roraima and TV Amapá), at the Central de Jornalismo (journalism Center) located in the capital of the State of Amazonas and its effects on the routine of the community from the municipality of Manacapuru, which has become not only consumer of information, but also its protector. As a theoretical reference underlying Castells’ (1999, 2001, 2003) approaches, with the theory of network society through access to information; Dizard (2000) with the theory of old and new medias, analyzed on a time-space scale, in the context of the Amazon Region; and Milanesi (1978) with a reflection regarding the impact influence of old and new medias on peripheral areas, in regards to the existence of a central area. The research, an exploratory-descriptive case study, comprises communication as a result of a historical process which, in order to meet the society’s constantly changing demands, produces at the same time, through science, new technologies. The applied investigative techniques consist of document research with quantitative and qualitative data collection survey, by using resources such as questionnaires, semistructured interviews, semi-structured and participative observation. Unpublished and standardized data collected in this study aimed at contributing to the successful scientific knowledge production regarding the Amazon reality, as there is an expectation the results may be used as reference to other areas and investigations.
Esta dissertação investiga o efeito do sistema FTP (File Transfer Protocol ou Protocolo de Transferência de Arquivo) no processo de produção do telejornalismo das emissoras da Rede Amazônica (TV Amazonas, TV Rondônia, TV Acre, TV Roraima e TV Amapá), a partir da Central de Jornalismo sediada na capital do estado no Amazonas e seus efeitos no cotidiano da comunidade do município de Manacapuru, que passou a ser não apenas consumidora de informação, mas também produtora dela. Como referencial teórico embasa a reflexão nas abordagens de Castells (1999, 2001, 2003) com a teoria da sociedade em rede por meio do acesso à informação; Dizard (2000) com a teoria das velhas e novas mídias, analisadas, em uma escala tempo-espaço, ao contexto da região amazônica; e Milanesi (1978) com a reflexão acerca da influência do impacto das velhas e novas mídias em áreas periféricas, em relação à existência de uma área central. A pesquisa, um estudo de caso de caráter exploratório-descritivo, compreende a comunicação como resultado de um processo histórico que para atender as demandas da sociedade em constante transformação, produz em paralelo, por meio da ciência, novas tecnologias. As técnicas de investigação empregadas consistem em pesquisa documental com levantamento de dados quantitativos e qualitativos, pautadas no recurso de questionários, entrevistas semi-estruturadas, observação semi-estruturada e participante. Os dados inéditos levantados e sistematizados neste estudo tiveram por objetivo contribuir com o processo de produção do conhecimento científico acerca da realidade amazônica, na expectativa dos resultados virem a servir como referência para outras áreas e investigações.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
A large selection of hardware and software components are readily available for supporting Internet communication in the ground network environment. These components can be used to construct very powerful and flexible communication systems. The Operating Missions as Nodes on the Internet (OMNI) project at NASA/GSFC has been defining and demonstrating ways to use standard Internet technologies for future space communication. Theses concepts and technologies are also applicable to test range telemetry applications. This paper identifies the network equipment and protocols to support end-to-end IP communication from range sensors and spacecraft instruments to end users. After identifying the end-to-end network hardware and software components, the paper discusses which ones are currently available and lists specific examples of each. This includes examples of space missions currently using Internet technology for end-to-end communication. It also lists missing pieces and includes information on their current status. The goal of this paper is also to stimulate thought and discussion on what steps need to be taken to start filling in the remaining missing pieces for end-to-end range and space network connectivity.

Inom varje verksamhet förekommer det alltid någon form av projektplanering när man vill bedriva sin verksamhet på en ny marknad. Dessa typer av förberedelser görs på olika sätt och utmaningen för företagen blir att använda sig av rätt etableringsstrategi. För att lyckas med implementering av ett projekt, på respektive marknad som organisationer verkar på, är en utav framgångsfaktorerna att ha en tydlig och genomtänkt metod. Företaget Beta erbjuder molnbaserade tjänster inom tullhantering där man skapar lösningar som hjälper andra företag att hantera sina tullärenden. Aktören är etablerad på den svenska marknaden och vill prova att erbjuda sina IT-lösningar i Norge. Företaget har därför ett behov av att undersöka hur den norska marknaden ser ut, om det finns en möjlighet att bredda deras befintliga systemlösningar och i så fall hur de ska gå tillväga för att få ett fungerande system som kan kommunicera med norska tullverket. I rapporten föreslås en metod som kan användas som underlag vid utvidgning av en verksamhet till nya marknader. Utvecklingsprocessen som presenteras ska också kunna generaliseras, fungera som underlag och användas även av andra företag som ställs inför samma utmaning som Beta. Denna rapport innehåller även en analys av den norska marknaden. Det finns en jämförelse mellan delar av svenska och norska tullsystemet och en presentation av de ändringar som behöver göras utifrån skillnader som finns. Som resultat ger rapporten en tydlig bild av hur man möjligen kan gå tillväga för att ta sig an liknande problem. Författarna presenterar även ett resultat som beskriver en lösning till Betas problem.
Within each activity, there is always some kind of project planning when you want to do business in a new market. These types of preparation are done in different ways and the challenge for companies is to make use of the right establishment strategy. To succeed in implementing a project, on the respective market that organizations are working on, one of the success factors is to have a clear and thoughtful approach. The company Beta offers cloud-based customs management services, which provide solutions that help other companies handle their customs issues. Beta is established in the Swedish market and wants to try to offer their IT solutions in Norway. The company therefore has a need to investigate how the Norwegian market looks, if there is an opportunity to broaden their existing system solutions and, if so, how they should go about getting a working system that can communicate with the Norwegian customs office. The report proposes a method that can be used as a basis for expanding a business to new markets. The development process presented should also be generalized, serve as a basis, and used by other companies facing the same challenge as Beta. This report also contains an analysis of the Norwegian market. There is a comparison between parts of the Swedish and Norwegian customs system and a presentation of the changes that need to be made based on differences. As a result, the report provides a clear picture of how one might possibly be able to address similar problems. The project members also present a result describing a solution to Beta's problems.

The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990's. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90's saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM.

This project is a web application for two types of bookstores an E-Bookstore and a PDF-Bookstore. Both are document sellers, however, The E-Bookstore is not a currency user. The PDF-Bookstore sells PDF documents and issues a lightweight currency called Scart. Customers can sell their PDF documents to earn Scart currency and buy PDF documents by paying with Scart.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada
The CCSDS SCPS FP file transfer performance is compared with that of TCP/IP FTP in a simulated satellite channel environment. The comparison is made as a function of channel bit error rate and forward/return data rates. From these simulations, we see that both protocols work well when the channel error rate is low (below 10^-6) and the SCPS FP generally performs better when the error rate is higher. We also noticed a strong effect on the SCPS FP throughput as a function of forward transmission rate when running unbalanced channel tests.

Il lavoro è stato suddiviso in tre macro-aree. Una prima riguardante un'analisi teorica di come funzionano le intrusioni, di quali software vengono utilizzati per compierle, e di come proteggersi (usando i dispositivi che in termine generico si possono riconoscere come i firewall). Una seconda macro-area che analizza un'intrusione avvenuta dall'esterno verso dei server sensibili di una rete LAN. Questa analisi viene condotta sui file catturati dalle due interfacce di rete configurate in modalità promiscua su una sonda presente nella LAN. Le interfacce sono due per potersi interfacciare a due segmenti di LAN aventi due maschere di sotto-rete differenti. L'attacco viene analizzato mediante vari software. Si può infatti definire una terza parte del lavoro, la parte dove vengono analizzati i file catturati dalle due interfacce con i software che prima si occupano di analizzare i dati di contenuto completo, come Wireshark, poi dei software che si occupano di analizzare i dati di sessione che sono stati trattati con Argus, e infine i dati di tipo statistico che sono stati trattati con Ntop. Il penultimo capitolo, quello prima delle conclusioni, invece tratta l'installazione di Nagios, e la sua configurazione per il monitoraggio attraverso plugin dello spazio di disco rimanente su una macchina agent remota, e sui servizi MySql e DNS. Ovviamente Nagios può essere configurato per monitorare ogni tipo di servizio offerto sulla rete.

Les mécanismes de coopération sont de plus en plus important dans les communications sans fil et réseaux permettant d'accroître les performances du système et ce en diminuant la consommation d'énergie, en augmentant la capacité du système et en rendant les taux de perte de paquets plus petits. L'idée de coopération peut être retracée par une étude en théorie de l'information sur le canal à relais dans le réseau cellulaire. D'un point de vue système, puisque un mobile (MS) a des limites de taille (antenne unique), de puissance, de coût et de matériel, il devient irréalisable d'utiliser la technologie MIMO pour un MS. Les utilisateurs mobiles avec antennes uniques peuvent encore profiter de la diversité spatiale par le biais de transmissions coopératives codées en espace temps. L'objectif de cette thèse est d'introduire et de discuter de diverses stratégies de coopération dans les communications sans fil. Dans la première partie, nous présentons une analyse de performances de bout en bout d'une communication coopérative asynchrone et à saut multiple, utilisant des relais regénératifs évoluant dans un canal de Rayleigh en évanouissement plat. Le schéma de conception est basé sur un précodage sur les trames qui seront encodés par paires. Ce précodage est basé sur l'ajout d'un préfixe cyclique, contenant une séquence d'apprentissage. Nous développons le taux d'erreur sur les bits et le taux d'erreur sur les bites de bout en bout relativement à une modulation BPSK, pour des canaux à gains égaux et à gains différents. Nous présentons aussi les performances en taux d'erreur sur les trames et le taux d'erreur sur les trames de bout en bout. Finalement, nous présentons une comparaison entre trois configurations que nous avons introduit, différenciées par le degré de coopération. La deuxième partie contient deux chapitres. Dans le premier chapitre, nous considérons un système dans lequel un relais choisit de coopérer que si le canal source-relais est d'une qualité acceptable et nous évaluons l'utilité du relayage lorsque la source agit aveuglément et ignore la décision des relais s'ils peuvent coopérer ou non. Dans notre étude, nous considérons de relais regénératifs pour lesquels les décisions de coopération sont fondées sur un rapport signal à bruit (SNR) seuil et d'examiner l'éventuel impact d'une détection et transmission d'erreurs par le relais. Nous dérivons le taux d'erreur sur les bits (BER) de bout en bout pour une modulation BPSK et nous examinons deux stratégies de répartition de puissance entre la source et le relais afin de minimiser le BER de bout en bout au niveau de destination pour un ordre de SNR élevé. Dans le second chapitre, nous consédérons un schéma dans lequel un relais choisit de coopérer seulement lorsque le canal source-destination est d'une qualité inaccepable. Dans notre étude, nous considérons une relais regénératif pour lequel la décision de coopération est basée sur un seuil du rapport signal à bruit et nous considérons les effets d'une éventuelle détection et transmission d'erreur par le relais. Nous développns l'expression du taux d'erreur sur les bits pour une modulation BPSK et nous examinons une stratégie optimale permettant de minimiser ce BER de bout en bout pour un orde de SNR élevé. Dans la troisième partie, nous considérons un canal à accès multiple MAC où deux utilisateurs communiquent avec une destination commune. Chaque utilisateur agit mutuellement comme un relais pour l'autre ainsi qu'il tient à transmettre ses propres informations, par opposition à une consacration totale au relayage. Nous tenons à évaluer l'utilité du relais d'un point de vue somme des taux du système (sum rate) plutôt que d'un point de vue de l'utilisateur bénéficiant de la coopération qui se fait habituellement. Nous faisons cela en permettant un compromis entre le relayage et la transmission de données via une d'allocation des ressources. Concrètement, nous proposons un régime de transmission coopérative permettant à chaque utilisateur d'allouer une certaine fraction de puissance pour sa propre transmission de données tandis que le reste est consacré au relayage. Le protocole sous-jacent est basé sur une modification du protocole Non-Orthogonal Amplify and Forward (NAF). Nous développons les expressions de capacité pour notre modèle et nous présentons une allocation de puissance optimisant une forme approche du sum rate, pour les cas centralisé et distribué. Dans le scénario distribué, une connaissance hybride de l'état du canal, partie statistique et partie instantanée, est exploitée. L'algorithme d'allocation de puissance dans le cas centralisé indique que, même dans une coopération mutuelle comme la notre, quelle que soit la réalisation du canal, la coopération mutuelle n'est jamais réelle, c'est-à-dire l'un des utilisateurs allouera toujours une puissance nulle pour relayer les données de l'autre, et donc agit égoïstement. Mais dans le cadre distribué, nos résultats indiquent que la somme des taux est maximisée lorsque les deux mobiles agissent égoïstement
Cooperative mechanisms are becoming increasingly important in wireless communications and networks to substantially enhance system performance with respect to much less power consumption, higher system capacity and smaller packet loss rate. The idea of cooperation can be traced back to the information theory investigation on relay channel in cellular network. From the system point of view, since Mobile Station (MS) has limitations in single antenna, power, cost and hardware, it is infeasible to use MIMO technology in MS. Mobile users with single antennas can still take advantage of spatial diversity through cooperative space-time encoded transmission. The objective of this thesis is to introduce and discuss various cooperative strategies in wireless communications. In the first part, we present an end-to-end performance analysis of two-hop asynchronous cooperative diversity with regenerative relays over Rayleigh block-flat-fading channels, in which a precoding frame-based scheme with packet-wise encoding is used. This precoding is based on the addition of a cyclic prefix which is implemented as a training sequence. We derive, for equal and unequal sub-channel gains, the bit-error rate and the end-to-end bit-error rate expressions for binary phase-shift keying. We also present the performance of the frame-error rate and the end-to-end frame-error rate. Finally, comparisons between three system configurations, differing by the amount of cooperation, are presented. The second part contains two chapters. In the first chapter, we consider a scheme in which a relay chooses to cooperate only if its source-relay channel is of an acceptable quality and we evaluate the usefulness of relaying when the source acts blindly and ignores the decision of the relays whether they may cooperate or not. In our study, we consider the regenerative relays in which the decisions to cooperate are based on a signal-to-noise ratio (SNR) threshold and consider the impact of the possible erroneously detected and transmitted data at the relays. We derive the end-to-end bit-error rate (BER) for binary phase-shift keying modulation and look at two power allocation strategies between the source and the relays in order to minimize the end-to-end BER at the destination for high SNR. In the second chapter, we consider a scheme in which the relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. In our study, we consider a regenerative relay in which the decision to cooperate is based on a signal-to-noise ratio (SNR) threshold and consider the effect of the possible erroneously detected and transmitted data at the relay. We derive an expression for the end-to-end bit-error rate (BER) of binary phase-shift keying (BPSK) modulation and look at the optimal strategy to minimize this end-to-end BER at the destination for high SNR. In the third part, we consider a multiple access MAC fading channel with two users communicating with a common destination, where each user mutually acts as a relay for the other one as well as wishes to transmit his own information as opposed to having dedicated relays. We wish to evaluate the usefulness of relaying from the point of view of the system's throughput (sum rate) rather than from the sole point of view of the user benefiting from the cooperation as is typically done. We do this by allowing a trade-off between relaying and fresh data transmission through a resource allocation framework. Specifically, we propose cooperative transmission scheme allowing each user to allocate a certain amount of power for his own transmitted data while the rest is devoted to relaying. The underlying protocol is based on a modification of the so-called non-orthogonal amplify and forward (NAF) protocol. We develop capacity expressions for our scheme and derive the rate-optimum power allocation, in closed form for centralized and distributed frameworks. In the distributed scenario, partially statistical and partially instantaneous channel information is exploited. The centralized power allocation algorithm indicates that even in a mutual cooperation setting like ours, on any given realization of the channel, cooperation is never truly mutual, i. E. One of the users will always allocate zero power to relaying the data of the other one, and thus act selfishly. But in distributed framework, our results indicate that the sum rate is maximized when both mobiles act selfishly

Au cours des dernières années, différents travaux de recherche ont été consacrés à l’étude et au développement des solutions de type réseau de capteurs sans fil. Ces travaux sont une réponse à l’augmentation du nombre d’objets connectés dans le monde avec le développement de l’internet des objets. La consommation d’énergie dans les réseaux de capteurs représente un des domaines les plus étudiés. Les communications dans les réseaux de capteurs représentent une part importante de leur consommation. Afin de réduire la consommation des communications dans les réseaux de capteurs, différents niveaux d’optimisation sont possibles. Dans ce contexte, différents travaux de recherches visant à réduire la consommation des émetteurs-récepteurs, grâce à des architectures innovantes, ont été menés à l’IM2NP. Beaucoup de ces travaux ont été consacrés aux radios impulsionnelles Ultra-Large Bande (ULB). En outre, les protocoles d’accès aux canaux de communications dans les réseaux de capteurs sont également importants quant à l’optimisation de leurs consommations. Les travaux de recherches proposés dans ce manuscrit, basés sur les travaux sur les radios impulsionnelles ULB réalisés au sein de l’IM2NP, proposent une optimisation de la consommation des réseaux de capteurs sur deux niveaux. Tout d’abord, un protocole asynchrone à base de radio de réveil d’accès au canal de communication adapté aux communications ULB est proposé ainsi que son étude énergétique. Suite à l'étude du protocole asynchrone proposé, la conception d’un récepteur de réveil semi-passif et d’un générateur d’impulsion ULB sous-GHz est abordée, et leurs performances en termes d’efficacité énergétique discutées
In recent years, research has been devoted to the study and development of Wireless Sensor Network (WSN). These research are a response to the increase of the connected objet number in the world with development of smartphones and Internet of things (IoT). Energy consumption in sensor networks is one of the most studied areas. In fact, the optimization of the consumption of the elements making up the sensor networks allows a reduction in the costs associated with their installation, operation and maintenance. Communications in sensor networks represent an important part of their power consumption. In order to reduce the consumption of communications in sensor networks, different levels of optimization are possible. In this context, various IM2NP research projects aimed at reducing transceiver consumption through innovative design were carried out. Much of this work has been devoted to Impulsionnal Radio Ultra-Wide Band (IR-UWB). Moreover, MAC protocols used to manage the communication channel access in wireless sensor networks are also important in optimizing their consumption. The research work proposed in this manuscript, based on the work on impulse radios UWB carried out within the IM2NP, propose an optimization of the consumption of sensor networks on two levels. Firstly, an asynchronous MAC protocol based on radio wake-up radio suitable for UWB communications is proposed as well as its energy study. Following the study of the proposed asynchronous protocol, the design of a low power semi-passive wake-up receiver (WuRx) and a UWB sub-GHz impulse generator is presented and their performance in terms of energy efficiency discussed

Au cours des dernières décennies, le besoin pour des communications multimédia en mobilité est devenu indéniable dans les réseaux de type IP, ainsi la gestion de la mobilité et la continuité de session est depuis plusieurs années un problème de recherche très important aussi bien pour le milieu académique qu’industriel. Comme l'hétérogénéité des réseaux d’accès est en perpétuelle évolution, l'intégration des différents types de réseaux sans fil au niveau de la couche IP est devenue un domaine de recherche difficile et inévitable. L'un des problèmes les plus importants liés à l'exécution de la gestion de la mobilité concerne le fait que la couche d'application souffre de la modification d'adresses IP au cours du mouvement du nœud mobile alors que celle-ci construit sa session sur la base de l’adresse IP de connexion au réseau. Une nouvelle approche d'amélioration de la prise en charge de la mobilité propose de séparer l'identification de session et l'identification de l’emplacement ou l’attachement au réseau. Donc, par la séparation de ces deux concepts, les sessions ne sont pas identifiés par les adresses IP qui elles sont dynamiques puisque la mobilité dans le réseau impose le changement d’adresse IP, mais les nouveaux identificateurs uniques qui définissent un nœud et qui ne change pas à cause de la mobilité ce qui offrirait une stabilité pour le niveau applicatif. Selon ces concepts, Host Identity Protocol (HIP) est l'une des solutions dominantes en recherches qui est proposé par l'IETF et l’IRTF. Dans cette thèse, le protocole HIP est principalement examiné et de nouvelles améliorations de la mobilité sur la base de ce protocole ont été conçues et mises en place
Over the last decades, with rapid and tremendous growth of IP networks in mobile and wireless environments, mobility management and session continuity has become a more important issue. As the heterogeneity increases in network environments and gradual spread of Internet of Things wave, the integration of different types of wireless networks in the IP layer became a challenging and inevitable research area. One of the most important issues related to mobility management is related to the fact that the application layer suffers from the changing of IP addresses during the movement of the mobile node. It is expected the network layer and above layers to be aware of movement of mobile nodes. New wave in the improvement ideas on this concept is separating the session identification and the location identification. This avoids the applications to suffer when the IP address changes during the mobility. This new approach needs to introduce a new layer in the TCP/IP protocol stack, on top of the IP layer that will handle the new identifiers correspondent with the current IP address or new complete architecture designs which are inheriting locator/identifier separation idea. According to these concepts, Host Identity Protocol (HIP) is one of the dominant and prominent researches that is proposed by IETF and IRTF. This protocol proposes to solve the locator/identifier split problem by also including the security support. In this thesis, predominantly HIP protocol is examined and new mobility enhancements based on this protocol have been designed and introduced

Context. Scalability and bittrate is an large concern when build-ing infrastructure and application for video content delivery. Manyresearch and companies have for a long time looked at peer to peertechnology as a way of solving the issue by utilizing the clients capac-ity.Objectives. The first objectives is to see if Dat protocol would be agood fit for video file delivery. Comparing with the widely used HTTPtoo see the differences in scalability and bitrate. The challenges withimplementing such a solution and tactic for the future if choosing to.Methods. In order to achieve the objectives of our research a compar-ing network experiment in similar manners and with the same clientbase was conducted.Conclusions. The Dat protocol show good scalability and perfor-mance especially on larger number of clients. Some future works suchas peer-selecting and load balancing are needed before Dat can be usedas protocol for video delivery on commerical sites.Keywords:P2P, Decentralized, Video, conten

碩士
國立臺灣科技大學
電子工程系
90
With the growth of Internet and network, the time that people stay on the Internet is increasing. The Internet is a public network of millions of computers, all sharing information. On the Internet, communications move back and forth across public lines and through numerous connections. More and more people pay much attention to the process of data transmission. Files Exchange, Letters Delivery, Transaction on Internet is involved with the personal privacy and security. The frequency of hacker invades the network of enterprise raises constantly. The security on the Internet will be doubted. Is the Internet safe? The enterprise stresses more on the Internet security. If the secret inside enterprise is public, it will cause huge damage to enterprise. When you see a beautiful picture or a practical file on the Internet, you must want to download it to your computer. If you have such requirements, you can use FTP this tool. Through the FTP, you can download or upload some useful system tools. In WWW browser also contain this function, but the speed of transmission is slower. After entering the site, username, and password, you can login the remote server. You can download the files on remote machine at will, but is its organization secure? Can you prove the process of login is secure? As with any public lines, interception is possible. The hackers even change your password and use your ID to enter remote system. These questions we will discuss in this thesis. We will adopt a technique of visual secret sharing to implement remote authentication in this thesis. We will discuss the shortcomings of traditional authentication, the theorem of VSSS, the basic algorithm of encryption to be used in this thesis, how to download the pictures of authentication and so on. Lastly, we will transplant the whole VSSS theorem to a remote authentication of files transmission. File transfer software corresponds to the method proposed in this thesis.

碩士
國立中山大學
資訊工程學系研究所
98
Cloud computing is pervasive in our daily life. For instance, I usually use Google’s GMail to receive e-mail, Google Document to edit documents online and Google Calendar to make my daily schedule. We can say that Google provides a “Platform as a Service (PaaS)”, which delivers a computing platform as a service, and the platform sustaining lots of cloud applications such as I mentioned above. However, the cloud computing platform of Google is private: we cannot trace its source code and make cloud applications on it! Fortunately, there’s an open source project supported by Apache named “Hadoop”, which has a distributed file system which is very like Google File System (GFS) called “Hadoop distributed file system (HDFS)”. In order to observe the properties of HDFS, we design and implement a HDFS-based FTP server system called FTP-ON-HDFS system, say, a FTP server whose storage is HDFS. There are a web-console for FTP administrator, a FreeRADIUS server and a MySQL database for user authentication, a NameNode daemon on its machine, a SecondaryNameNode on its machine and five DataNode daemons and on five different machines in FTP-ON-HDFS system. Our FTP-ON-HDFS system can tune two QoS parameters: “data block size” and “data replication”. Then, we tuned “data block size” and “data replication” in our system and compared its performance with Hadoop File System (FS) shell command and normal vsftpd. On the other hand, FUSE can mount HDFS from remote cluster to local machine, and make use of the permission of the local machine to manage HDFS. So, we compared the performance of FUSE with HDFS (FUSE-DFS) and our FTP-ON-HDFS system.

碩士
淡江大學
資訊工程學系碩士在職專班
94
This thesis propose a file transfer protocol for VON.This protocol is based on the “IP-based Transformation Mechanism from TCP/IP Network to Voronoi-based Overlap Network” and “A Tree-Like Multicast Search Mechanism on a Voronoi-based Overlay Network Virtual Environment” to construct VON virtual environment. This file transfer protocol supports the peer-to-peer file transmission for sharing the resources with each other. We propose a switch mechanism which uses a characteristic of VON for resuming the file transfer,when the file transmitting is interrupted. According to the simulation result of this thesis, it represents the file switching and resuming transfer mechanism can enhance the speed of file transmission.

by Pan Jiao Feng.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references (leaves 89-93).
Abstract also in Chinese.
Abstract --- p.i
Acknowledgments --- p.v
List of Tables --- p.x
List of Figures --- p.xi
Chapter Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Graph definitions --- p.2
Chapter 1.2 --- The S box graph --- p.2
Chapter 1.3 --- The file transfer graph --- p.4
Chapter 1.4 --- "(g, f)-factor and (g, f)-factorization" --- p.5
Chapter 1.5 --- Thesis contributions --- p.6
Chapter 1.6 --- Organization of the thesis --- p.7
Chapter Chapter 2. --- On the Optimal Four-way Switch Box Routing Structures of FPGA Greedy Routing Architectures --- p.8
Chapter 2.1 --- Introduction --- p.9
Chapter 2.1.1 --- FPGA model and S box model --- p.9
Chapter 2.1.2 --- FPGA routing --- p.10
Chapter 2.1.3 --- Problem formulation --- p.10
Chapter 2.2 --- Definitions and terminology --- p.12
Chapter 2.2.1 --- General terminology --- p.12
Chapter 2.2.2 --- Graph definitions --- p.15
Chapter 2.2.3 --- The S box graph --- p.15
Chapter 2.3 --- Properties of the S box graph and side-to-side graphs --- p.16
Chapter 2.3.1 --- On the properties of the S box graph --- p.16
Chapter 2.3.2 --- The properties of side-to-side graphs --- p.19
Chapter 2.4 --- Conversion of the four-way FPGA routing problem --- p.23
Chapter 2.4.1 --- Conversion of the S box model --- p.24
Chapter 2.4.2 --- Conversion of the DAAA model --- p.26
Chapter 2.4.3 --- Conversion of the DADA model --- p.27
Chapter 2.4.4 --- Conversion of the DDDA model --- p.28
Chapter 2.5 --- Low bounds of routing switches --- p.28
Chapter 2.5.1 --- The lower bound of the DAAA model --- p.29
Chapter 2.5.2 --- The lower bound of the DADA model --- p.30
Chapter 2.5.3 --- The lower bound of the DDDA model --- p.31
Chapter 2.6 --- Optimal structure of one-side predetermined four-way FPGA routing --- p.32
Chapter 2.7 --- Optimal structures of two-side and three-side predetermined four-way FPGA routing --- p.45
Chapter 2.7.1 --- Optimal structure of two-side predetermined four-way FPGA routing --- p.46
Chapter 2.7.2 --- Optimal structure of three-side predetermined four-way FPGA routing --- p.47
Chapter 2.8 --- Conclusion --- p.49
Appendix --- p.50
Chapter Chapter 3. --- "Application of (0, f)-Factorization on the Scheduling of File Transfers" --- p.53
Chapter 3.1 --- Introduction --- p.53
Chapter 3.1.1 --- "(0,f)-factorization" --- p.54
Chapter 3.1.2 --- File transfer model and its graph --- p.54
Chapter 3.1.3 --- Previous results --- p.56
Chapter 3.1.4 --- Our results and outline of the chapter --- p.56
Chapter 3.2 --- NP-completeness --- p.57
Chapter 3.3 --- Some lemmas --- p.58
Chapter 3.4 --- Bounds of file transfer graphs --- p.59
Chapter 3.5 --- Comparison --- p.62
Chapter 3.6 --- Conclusion --- p.68
Chapter Chapter 4. --- "Decomposition Graphs into (g,f)-Factors" --- p.69
Chapter 4.1 --- Introduction --- p.69
Chapter 4.1.1 --- "(g,f)-factors and (g,f)-factorizations" --- p.69
Chapter 4.1.2 --- Previous work --- p.70
Chapter 4.1.3 --- Our results --- p.72
Chapter 4.2 --- Proof of Theorem 2 --- p.73
Chapter 4.3 --- Proof of Theorem 3 --- p.79
Chapter 4.4 --- Proof of Theorem 4 --- p.80
Chapter 4.5 --- Related previous results --- p.82
Chapter 4.6 --- Conclusion --- p.84
Chapter Chapter 5. --- Conclusion --- p.85
Chapter 5.1 --- About graph-based approaches --- p.85
Chapter 5.2 --- FPGA routing --- p.87
Chapter 5.3 --- The scheduling of file transfer --- p.88
Bibliography --- p.89
Vita --- p.94

Our work focuses on performance modelling of TCP-controlled file transfers in infrastructure mode IEEE 802.11 wireless networks, and application of the models in developing association schemes. A comprehensive set of analytical models is used to study the behaviour of TCP-controlled long and short file transfers in IEEE 802.11 WLANs. The results can provide insight into the performance of TCP-controlled traffic in 802.11 WLANs in a variety of different network environments. First, we consider several WLAN stations associated at rates r1, r2, ...,rk with an Access Point. Each station (STA) is downloading a long file from a local server, located on the LAN to which the AP is attached, using TCP. We assume that a TCP ACK will be produced after the reception of d packets at an STA. We model these simultaneous TCP-controlled transfers using a semi-Markov process. Our analytical approach leads to a procedure to compute aggregate download as well as per-STA throughputs numerically, and the results match simulations very well. Performance analysis of TCP-controlled long file transfers in a WLAN in infrastructure mode is available in the literature with one of the main assumptions being equal window size for all TCP connections. We extend the analysis to TCP-controlled long file uploads and downloads with different TCP windows. Our approach is based on the semi- Markov process considered in above work, but with arbitrary window sizes. We present simulation results to show the accuracy of the analytical model. Then, we obtain an association policy for STAs in an IEEE 802.11 WLAN by taking into account explicitly an aspect of practical importance: TCP controlled short file downloads interspersed with read times (motivated by web browsing). Our approach is based on two steps. First, we consider the analytical model mentioned above to obtain the aggregate download throughput. Second, we present a 2-node closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. These analytical results motivate the proposed association policy, called the Estimated Delay based Association (EDA) policy: Associate with the AP at which the expected file download time is the least. Simulations indicate that for a web-browsing type traffic scenario, EDA outperforms other policies that have been proposed earlier; the extent of improvement ranges from 12.8% to 46.4% for a 9-AP network. We extend the performance model by considering _le sizes drawn from heavy-tailed distributions. We represent heavy-tailed distributions using a 1 mixture of exponential distributions (following Cox's method). We provide a closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. Further, we analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the WLAN MAC. We extend this work to obtain throughputs in multirate scenarios. Simulations show that our approach is able to predict observed throughputs with a high degree of accuracy.

碩士
朝陽科技大學
網路與通訊研究所
96
File Transfer Protocol (FTP) is a type of Client-Server. It builds a server in Internet that provides files for users downloading. Traditional file transfer protocol uses a single server to supply users for downloading file. Since the performance of file transmission is limited by the throughput of the single server, FTP is not suitable for the large file downloading. Some scholars proposed distribution file transfer method to improve throughput of the FTP. But most distribution file transfer methods do not consider the quality of network transmission. It can’t produce the balanced division of sub-file size according to the actual transfer performance of network. It can’t speed up time of downloading file effectively. This study proposes two distributed and parallelized the file transmission methods. First method is called Modified Parallelized File Transfer Protocol (MFTP). This method removes Parallelized File Transfer Protocol (P-FTP) centralized control of information server. We use client to find optimum efficacy of transmission a mirror server that replaces P-FTP server. The MFTP improves the P-FTP centralized control of transmission efficiency. Second method is called Distributed Parallelized File Transfer Protocol (DFTP). The DFTP method uses actual delay time of transmission between the client and mirror servers that distributes suitable sub-file size. It can achieve the different transmission rate of each mirror servers, and complete transmission file at the same time. Besides, it also improves the download time of large file in the multiple users. In the simulations, we compare the performance of our methods with other scholars’. In the results, we use client itself to find a suitable mirror server. The client can measure actual performance of delay time of transmission between itself and mirror servers. According as these performances, it gets the most suitable sub-file size for each mirror server. Further, DFTP can disperse the overload of downloading files, and obtain the best transmission time to download large file in the multiple users environments.