Tesis sobre el tema "Control toolbox (Computer file)"

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
Includes bibliographical references (p. 47-53).
SFS (secure file system) is a global file system designed to be secure against all active and passive network attacks, provide a single namespace across all machines in the world, and avoid any form of centralized control. Using SFS, any unprivileged user can access any file server in the world securely and with no prior arrangement on the part of system administrators. New file servers are immediately accessible securely by all client machines. Users can name such new servers from any existing file system by specifying public keys in symbolic links. A prototype implementation of SFS installs easily, coexists with other file systems, and should port trivially to most UNIX platforms. Preliminary performance numbers on application benchmarks show that, despite its use of encryption and user-level servers, SFS delivers performance competitive with an in-kernel NFS implementation.
by David Mazières.
M.S.

Current shared file systems (NFS and SAMBA) are based on the local area network model. To these file systems, performance is the major issue. However, as the Internet grows, so does the distance between users and the Local Area Network. With this increase in distance, the latency increases as well. This creates a problem when multiple users attempt to work in a shared environment. Traditionally, the only way to collaborate over the Internet required the use of locks. These requirements motivated the creation of the State Difference Transformation algorithm that allows users non-blocking and unconstrained interaction across the Internet on a tree based structure. Fine Grain Locking, on the other hand, allows a user the ability to set a lock on a character or range of characters while using a form of the transformation algorithm listed above. This thesis proposes an implementation that integrates these two technologies as well as demonstrating the effectiveness and flexibility of State Difference Transformation. The implementation includes two applications that can be used to further research in both the transformation and locking communities. The first application allows users to create tests for SDT and Fine Grain Locking and verify the correctness of the algorithms in any given situation. The second application then furthers this research by creating a real-world groupware interface to a shared file system based on a clientserver architecture. This implementation demonstrates the usability and robustness of these algorithms in real world situations.

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).

The Design Metrics Research Team at Ball State University has developed a quality design metric D(G), which consists of an internal design metric Di, and an external design metric De. This thesis discusses applying design metrics to the ROCC-Radar On-line Command Control project received from Harris Corporation. Thus, the main objective of this thesis is to analyze the behavior of D(G), and the primitive components of this metric.Error and change history reports are vital inputs to the validation of design metrics' performance. Since correct identification of types of changes/errors is critical for our evaluation, several different types of analyses were performed in an attempt to qualify the metric performance in each case.This thesis covers the analysis of 666 FORTRAN modules with approximately 142,296 lines of code.
Department of Computer Science

The development of high quality software the first time, greatly depends upon the ability to judge the potential quality of the software early in the life cycle. The Software Engineering Research Center design metrics research team at Ball State University has developed a metrics approach for analyzing software designs. Given a design, these metrics highlight stress points and determine overall design quality.The purpose of this study is to analyze multiple software releases of the Advanced Field Artillery Tactical Data System (AFATDS) using design metrics. The focus is on examining the transformations of design metrics at each of three releases of AFATDS to determine the relationship of design metrics to the complexity and quality of a maturing system. The software selected as a test case for this research is the Human Interface code from Concept Evaluation Phase releases 2, 3, and 4 of AFATDS. To automate the metric collection process, a metric tool called the Design Metric Analyzer was developed.Further analysis of design metrics data indicated that the standard deviation and mean for the metric was higher for release 2, relatively lower for release 3, and again higher for release 4. Interpreting this means that there was a decrease in complexity and an improvement in the quality of the software from release 2 to release 3 and an increase in complexity in release 4. Dialog with project personnel regarding design metrics confirmed most of these observations.
Department of Computer Science

Cette these est consacree a la modelisation par files d'attente de certains systemes informatiques. Le chapitre i analyse un systeme classique de files d'attente en serre. Les chapitres ii, iii et iv abordent l'analyse de modeles d'allocation d'une ressource unique dans les reseaux de communication (boucle, bus. . . ). Ceci se traduit par la recherche de politiques optimales de service dans une file d'attente multiclasse avec contraintes. Les chapitres v et vi traitent de l'evaluation des performances de deux protocoles de communication multi-acces

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.

Tang, Yang.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (p. 60-65).
Abstracts in English and Chinese.
Abstract --- p.i
Acknowledgement --- p.iv
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Policy-based File Assured Deletion --- p.7
Chapter 2.1 --- Background --- p.7
Chapter 2.2 --- Policy-based Deletion --- p.9
Chapter 3 --- Basic Design of FADE --- p.13
Chapter 3.1 --- Entities --- p.13
Chapter 3.2 --- Deployment --- p.15
Chapter 3.3 --- "Security Goals, Threat Models, and Assumptions" --- p.16
Chapter 3.4 --- The Basics - File Upload/Download --- p.18
Chapter 3.5 --- Policy Revocation for File Assured Deletion --- p.23
Chapter 3.6 --- Multiple Policies --- p.23
Chapter 3.7 --- Policy Renewal --- p.25
Chapter 4 --- Extensions of FADE --- p.27
Chapter 4.1 --- Access Control with ABE --- p.27
Chapter 4.2 --- Multiple Key Managers --- p.31
Chapter 5 --- Implementation --- p.35
Chapter 5.1 --- Representation of Metadata --- p.36
Chapter 5.2 --- Client --- p.37
Chapter 5.3 --- Key Managers --- p.38
Chapter 6 --- Evaluation --- p.40
Chapter 6.1 --- Experimental Results on Time Performance of FADE --- p.41
Chapter 6.1.1 --- Evaluation of Basic Design --- p.42
Chapter 6.1.2 --- Evaluation of Extensions --- p.46
Chapter 6.2 --- Space Utilization of FADE --- p.49
Chapter 6.3 --- Cost Model --- p.51
Chapter 6.4 --- Lessons Learned --- p.53
Chapter 7 --- Related Work --- p.54
Chapter 8 --- Conclusions --- p.58
Bibliography --- p.60

M.Com.
Information and the IT systems that support it are important business assets. Their availability, integrity and confidentiality are essential to maintain an organisations competitive edge, cash flow, profitability, company image and compliance with legal requirements. Organisations world-wide are now facing increased security threats from a wide range of sources. Information systems may be the target of a range of serious threats including computer-based fraud, espionage, sabotage, vandalism and other sources of failure or disaster ...

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.

Quality assurance forms an integral part of education and training programme delivery. The purpose of this research was to determine whether the quality management systems (QMS) used by nursing education institutions in Gauteng are aligned to the SAQA criteria and guidelines for education and training providers. A quantitative, descriptive and exploratory design was followed using a self-administered questionnaire as data gathering instrument. A total of 32 respondents from three selected nursing education institutions completed the questionnaire. The data were analysed by using the Statistical Package for Social Sciences (SPSS) program. The findings revealed that the nursing education institutions only partially comply with SAQA’s core criteria for quality management systems. Recommendations to improve the current QMS were made.
Health Studies
M.A. (Health Studies)