The role of the host in a cooperating mainframe and workstation environment, volumes 1 and 2

In recent years, advancements made in computer systems have prompted a move from centralized computing based on timesharing a large mainframe computer to distributed computing based on a connected set of engineering workstations. A major factor in this advancement is the increased performance and lower cost of engineering workstations. The shift to distributed computing from centralized computing has led to challenges associated with the residency of application programs within the system. In a combined system of multiple engineering workstations attached to a mainframe host, the question arises as to how does a system designer assign applications between the larger mainframe host and the smaller, yet powerful, workstation. The concepts related to real time data processing are analyzed and systems are displayed which use a host mainframe and a number of engineering workstations interconnected by a local area network. In most cases, distributed systems can be classified as having a single function or multiple functions and as executing programs in real time or nonreal time. In a system of multiple computers, the degree of autonomy of the computers is important; a system with one master control computer generally differs in reliability, performance, and complexity from a system in which all computers share the control. This research is concerned with generating general criteria principles for software residency decisions (host or workstation) for a diverse yet coupled group of users (the clustered workstations) which may need the use of a shared resource (the mainframe) to perform their functions

Failure detection and repair of threads in CTAS

Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 73).Reliable, error-free software is hard to come by, and this is especially true for newer, larger, or more complex programs. CTAS, an air traffic control tool, falls into this category, making it a good candidate for research on error compensation. Specifically, this thesis addresses the issue of thread crashes in one portion of CTAS. We reimplement the thread structure in question around a simpler problem, and develop a failure detector and an accompanying repair mechanism to monitor it. These add-on components provide the application with thread consistency by swiftly and transparently recovering from crashes, thereby yielding a more stable, self-sufficient, and generally more reliable operating environment.by Farid Jahanmir.M.Eng.and S.B

Avionics architecture studies for the entry research vehicle

This report is the culmination of a year-long investigation of the avionics architecture for NASA's Entry Research Vehicle (ERV). The Entry Research Vehicle is conceived to be an unmanned, autonomous spacecraft to be deployed from the Shuttle. It will perform various aerodynamic and propulsive maneuvers in orbit and land at Edwards AFB after a 5 to 10 hour mission. The design and analysis of the vehicle's avionics architecture are detailed here. The architecture consists of a central triply redundant ultra-reliable fault tolerant processor attached to three replicated and distributed MIL-STD-1553 buses for input and output. The reliability analysis is detailed here. The architecture was found to be sufficiently reliable for the ERV mission plan

Use case scenarios and preliminary reference model

This document provides the starting point for the development of dependability solutions in the HIDENETS project with the following contents: (1) A conceptual framework is defined that contains the relevant terminology, threats and general requirements. This framework is a HIDENETS relevant subset of existing state-of-the-art views in the scientific dependability community. Furthermore, the dependability framework contains a first list of relevant functionalities in the communication and middleware level, which will act as input for the architectural discussions in HIDENETS work packages (WPs) 2 and 3. (2) A set of 17 applications with HIDENETS relevance is identified and their corresponding dependability requirements are derived. These applications belong mostly to the class of car-tocar and car-to-infrastructure services and have been selected due to their different types of dependability needs. (3) The applications have been grouped in six HIDENETS use cases, each consisting of a set of applications. The use cases will be the basis for the development of the dependability solutions in all other WPs. Together with a description of each use-case, application-specific architectural aspects are identified and corresponding failure modes and challenges are listed. (4) The business impact of dependability solutions for these use cases is analysed. (5) A preliminary definition of a HIDENETS reference model is provided, which contains highlevel architectural assumptions. This HIDENETS reference model will be further developed in the course of the HIDENETS projects in close cooperation with the other WPs, which is the reason why the preliminary version also contains a collection of potential contributions from other WPs that shall be developed and investigated in the course of the HIDENETS project. In summary, the identified use-cases and their requirements clearly show the large number of dependability related challenges. First steps towards technical solutions have been made in this report in the preliminary reference model, whereas the other work-packages have started in the meanwhile to develop such solutions further based on 'middleware technology' (WP2), 'communication protocols' (WP3), 'quantitative analysis methodology' (WP4), and 'design and testing methodology' (WP5

Electronic security - risk mitigation in financial transactions : public policy issues

This paper builds on a previous series of papers (see Claessens, Glaessner, and Klingebiel, 2001, 2002) that identified electronic security as a key component to the delivery of electronic finance benefits. This paper and its technical annexes (available separately at http://www1.worldbank.org/finance/) identify and discuss seven key pillars necessary to fostering a secure electronic environment. Hence, it is intended for those formulating broad policies in the area of electronic security and those working with financial services providers (for example, executives and management). The detailed annexes of this paper are especially relevant for chief information and security officers responsible for establishing layered security. First, this paper provides definitions of electronic finance and electronic security and explains why these issues deserve attention. Next, it presents a picture of the burgeoning global electronic security industry. Then it develops a risk-management framework for understanding the risks and tradeoffs inherent in the electronic security infrastructure. It also provides examples of tradeoffs that may arise with respect to technological innovation, privacy, quality of service, and security in designing an electronic security policy framework. Finally, it outlines issues in seven interrelated areas that often need attention in building an adequate electronic security infrastructure. These are: 1) The legal framework and enforcement. 2) Electronic security of payment systems. 3) Supervision and prevention challenges. 4) The role of private insurance as an essential monitoring mechanism. 5) Certification, standards, and the role of the public and private sectors. 6) Improving the accuracy of information on electronic security incidents and creating better arrangements for sharing this information. 7) Improving overall education on these issues as a key to enhancing prevention.Knowledge Economy,Labor Policies,International Terrorism&Counterterrorism,Payment Systems&Infrastructure,Banks&Banking Reform,Education for the Knowledge Economy,Knowledge Economy,Banks&Banking Reform,International Terrorism&Counterterrorism,Governance Indicators

Research into software executives for space operations support

Research concepts pertaining to a software (workstation) executive which will support a distributed processing command and control system characterized by high-performance graphics workstations used as computing nodes are presented. Although a workstation-based distributed processing environment offers many advantages, it also introduces a number of new concerns. In order to solve these problems, allow the environment to function as an integrated system, and present a functional development environment to application programmers, it is necessary to develop an additional layer of software. This 'executive' software integrates the system, provides real-time capabilities, and provides the tools necessary to support the application requirements

Sharing and viewing segments of electronic patient records service (SVSEPRS) using multidimensional database model

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The concentration on healthcare information technology has never been determined than it is today. This awareness arises from the efforts to accomplish the extreme utilization of Electronic Health Record (EHR). Due to the greater mobility of the population, EHR will be constructed and continuously updated from the contribution of one or many EPRs that are created and stored at different healthcare locations such as acute Hospitals, community services, Mental Health and Social Services. The challenge is to provide healthcare professionals, remotely among heterogeneous interoperable systems, with a complete view of the selective relevant and vital EPRs fragments of each patient during their care. Obtaining extensive EPRs at the point of delivery, together with ability to search for and view vital, valuable, accurate and relevant EPRs fragments can be still challenging. It is needed to reduce redundancy, enhance the quality of medical decision making, decrease the time needed to navigate through very high number of EPRs, which consequently promote the workflow and ease the extra work needed by clinicians. These demands was evaluated through introducing a system model named SVSEPRS (Searching and Viewing Segments of Electronic Patient Records Service) to enable healthcare providers supply high quality and more efficient services, redundant clinical diagnostic tests. Also inappropriate medical decision making process should be avoided via allowing all patients‟ previous clinical tests and healthcare information to be shared between various healthcare organizations. Multidimensional data model, which lie at the core of On-Line Analytical Processing (OLAP) systems can handle the duplication of healthcare services. This is done by allowing quick search and access to vital and relevant fragments from scattered EPRs to view more comprehensive picture and promote advances in the diagnosis and treatment of illnesses. SVSEPRS is a web based system model that helps participant to search for and view virtual EPR segments, using an endowed and well structured Centralised Multidimensional Search Mapping (CMDSM). This defines different quantitative values (measures), and descriptive categories (dimensions) allows clinicians to slice and dice or drill down to more detailed levels or roll up to higher levels to meet clinicians required fragment

An SDN QoE Monitoring Framework for VoIP and video applications

Τα τελευταία χρόνια έχει σημειωθεί ραγδαία άνοδος του κλάδου των κινητών επικοινωνιών, αφού η χρήση των κινητών συσκευών εξαπλώνεται με ταχύτατους ρυθμούς και αναμένεται να συνεχίσει τη διείσδυσή της στην καθημερινότητα των καταναλωτών. Το γεγονός αυτό, σε συνδυασμό με τους περιορισμούς που θέτει η τρέχουσα δομή των δικτύων επικοινωνιών, καθιστά αναγκαία την ανάπτυξη νέων δικτύων με αυξημένες δυνατότητες, ώστε να είναι δυνατή η εξυπηρέτηση των χρηστών με την καλύτερη δυνατή ποιότητα εμπειρίας και ταυτόχρονα τη βέλτιστη αξιοποίηση των πόρων του δικτύου. Μία νέα δικτυακή προσέγγιση αποτελεί η δικτύωση βασισμένη στο λογισμικό (Software Defined Networking - SDN), η οποία αφαιρεί τον έλεγχο από τις συσκευές προώθησης του δικτύου, και οι αποφάσεις λαμβάνονται σε κεντρικό σημείο. Η ποιότητα υπηρεσίας που αντιλαμβάνεται ο χρήστης, ή αλλιώς ποιότητα εμπειρίας, κρίνεται ζήτημα υψηλής σημασίας στα δίκτυα SDN. Η παρούσα διπλωματική εργασία έχει ως στόχο την παρουσίαση της τεχνολογίας SDN, την επισκόπηση της υπάρχουσας έρευνας στο πεδίο της ποιότητας εμπειρίας σε SDN δίκτυα και στη συνέχεια την ανάπτυξη μίας SDN εφαρμογής η οποία παρακολουθεί και διατηρεί την ποιότητας εμπειρίας σε υψηλά επίπεδα για εφαρμογές VoIP και video. Πιο συγκεκριμένα, η εφαρμογή SQMF (SDN QoE Monitoring Framework) παρακολουθεί περιοδικά στο μονοπάτι μετάδοσης των πακέτων διάφορες παραμέτρους του δικτύου, με βάση τις οποίες υπολογίζει την ποιότητα εμπειρίας. Εάν διαπιστωθεί ότι το αποτέλεσμα είναι μικρότερο από ένα προσδιορισμένο κατώφλι, η εφαρμογή αλλάζει το μονοπάτι μετάδοσης, και έτσι η ποιότητα εμπειρίας ανακάμπτει. Η δομή της παρούσας διπλωματικής εργασίας είναι η εξής: Στο κεφάλαιο 1 παρουσιάζεται η σημερινή εικόνα των δικτύων επικοινωνιών και οι προβλέψεις για τη μελλοντική εικόνα, καθώς και οι προκλήσεις στις οποίες τα σημερινά δίκτυα δε θα μπορούν να αντεπεξέλθουν. Στη συνέχεια στο κεφάλαιο 2 περιγράφεται αναλυτικά η τεχνολογία SDN ως προς την αρχιτεκτονική, το κύριο πρωτόκολλο που χρησιμοποιεί, τα σενάρια χρήσης της, την προτυποποίηση, τα πλεονεκτήματα και τα μειονεκτήματά της. Το κεφάλαιο 3 εισάγει την έννοια της ποιότητας εμπειρίας του χρήστη και παραθέτει ευρέως γνωστά μοντέλα υπολογισμού της για διάφορους τύπους εφαρμογών, που χρησιμοποιούνται στην παρούσα εργασία. Σχετικές υπάρχουσες μελέτες στο πεδίο της ποιότητας εμπειρίας σε δίκτυα SDN αλλά και συγκριτικός πίνακας μπορούν να βρεθούν στο κεφάλαιο 4. Τα επόμενα κεφάλαια αφορούν στην εφαρμογή SQMF που υλοποιήθηκε στα πλαίσια της παρούσας διπλωματικής εργασίας: το κεφάλαιο 5 περιγράφει αναλυτικά όλα τα προαπαιτούμενα εργαλεία και οδηγίες για την ανάπτυξη του SQMF, ενώ το κεφάλαιο 6 παρουσιάζει παραδείγματα όπου η ποιότητα εμπειρίας ενός δικτύου μπορεί να υποστεί μείωση. Τέλος, το κεφάλαιο 7 αναλύει σε βάθος τις σχεδιαστικές προδιαγραφές, τη λογική και τον κώδικα του SQMF και παρέχει επίδειξη της λειτουργίας του και αξιολόγησή του, ενώ το κεφάλαιο 8 συνοψίζει επιγραμματικά τα συμπεράσματα της παρούσας εργασίας και ανοιχτά θέματα για μελλοντική έρευνα.Lately, there has been a rapid rise of the mobile communications industry, since the use of mobile devices is spreading at a fast pace and is expected to continue its penetration into the daily routine of consumers. This fact, combined with the limitations of the current communications networks’ structure, necessitates the development of new networks with increased capabilities, so that users can be served with the best possible quality of service and at the same time with the optimal network resources utilization. A new networking approach is Software Defined Networking (SDN) which decouples the control from the data plane, transforming the network elements to simple forwarding devices and making decisions centrally. The quality of service perceived by the user, or quality of experience (QoE), is considered to be a matter of great importance in software defined networks. This diploma thesis aims at presenting SDN technology, reviewing existing research in the field of QoE on SDN networks and then developing an SDN application that monitors and preserves the QoE for VoIP and video applications. More specifically, the developed SDN QoE Monitoring Framework (SQMF) periodically monitors various network parameters on the VoIP/video packets transmission path, based on which it calculates the QoE. If it is found that the result is less than a predefined threshold, the framework changes the transmission path, and thus the QoE recovers. The structure of this diploma thesis is the following: Chapter 1 presents the current state of communications networks and predictions for the future state, as well as the challenges that current networks will not be able to cope with. Chapter 2 then describes in detail the SDN technology in terms of architecture, main control-data plane communication protocol, use cases, standardization, advantages and disadvantages. Chapter 3 introduces the concept of QoE and lists well-known QoE estimation models for various applications types, some of which were used in this thesis. Relevant existing studies in the field of QoE on SDN networks as well as a comparative table can be found in chapter 4. The following chapters concern the framework implemented in the context of this diploma thesis: Chapter 5 describes in detail all the required tools and instructions for the development of SQMF, while Chapter 6 presents examples where the QoE in a network can face degradation. Finally, Chapter 7 analyzes in depth SQMF's design principles, logic and code files, provides a demonstration of its operation and evaluates it, whereas Chapter 8 briefly summarizes the conclusions and of this thesis and future work points

Interface for the integration of DynaMIT with the Traffic Management Center

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (p. 117-121).by Manish Mehta.S.M

IPAD 2: Advances in Distributed Data Base Management for CAD/CAM

The Integrated Programs for Aerospace-Vehicle Design (IPAD) Project objective is to improve engineering productivity through better use of computer-aided design and manufacturing (CAD/CAM) technology. The focus is on development of technology and associated software for integrated company-wide management of engineering information. The objectives of this conference are as follows: to provide a greater awareness of the critical need by U.S. industry for advancements in distributed CAD/CAM data management capability; to present industry experiences and current and planned research in distributed data base management; and to summarize IPAD data management contributions and their impact on U.S. industry and computer hardware and software vendors