This survey covers rollback-recovery techniques that do not require special language constructs. In the first part of the survey we classify rollback-recovery protocols into checkpoint-based and log-based.Checkpoint-based protocols rely solely on checkpointing for system state restoration. Checkpointing can be coordinated, uncoordinated, or communication-induced. Log-based protocols combine checkpointing with logging of nondeterministic events, encoded in tuples called determinants. Depending on how determinants are logged, log-based protocols can be pessimistic, optimistic, or causal. Throughout the survey, we highlight the research issues that are at the core of rollback-recovery and present the solutions that currently address them. We also compare the performance of different rollback-recovery protocols with respect to a series of desirable properties and discuss the issues that arise in the practical implementations of these protocols.

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A survey of rollback-recovery protocols in message-passing systems

The Grid 2: Blueprint for a New Computing Infrastructure

A super-peer is a node in a peer-to-peer network that operates both as a server to a set of clients, and as an equal in a network of super-peers. Super-peer networks strike a balance between the efficiency of centralized search, and the autonomy, load balancing and robustness to attacks provided by distributed search. Furthermore, they take advantage of the heterogeneity of capabilities (e.g., bandwidth, processing power) across peers, which recent studies have shown to be enormous. Hence, new and old P2P systems like KaZaA and Gnutella are adopting super-peers in their design. Despite their growing popularity, the behavior of super-peer networks is not well understood. For example, what are the potential drawbacks of super-peer networks? How can super-peers be made more reliable? How many clients should a super-peer take on to maximize efficiency? we examine super-peer networks in detail, gaming an understanding of their fundamental characteristics and performance tradeoffs. We also present practical guidelines and a general procedure for the design of an efficient super-peer network.

Designing an Super-Peer Network

Applications: A Review

This second edition of Grune and Jacobs brilliant work presents new developments and discoveries that have been made in the field. Parsing, also referred to as syntax analysis, has been and continues to be an essential part of computer science and linguistics. Parsing techniques have grown considerably in importance, both in computer science, ie. advanced compilers often use general CF parsers, and computational linguistics where such parsers are the only option. They are used in a variety of software products including Web browsers, interpreters in computer devices, and data compression programs; and they are used extensively in linguistics.

Parsing Techniques: A Practical Guide

We present file guidelines of a new project whose main task is to exploit mobile computers, comlected via a Wireless Networks, in Personal Health systems, computerizing patient clinical records with sophisticated solutions for taking clinical infommtion at the point of care.

Mobile computing in a hospital: the WARD-IN-HAND project

A system architecture called the recovery metaprogram (RMP) is proposed. It separates the application from the recovery software, giving programmers a single environment that lets them use the most appropriate fault-tolerance scheme. To simplify the presentation of the RMP approach, it is assumed that the fault model is limited to faults originating in the application software, and that the hardware and kernel layers can mask their own faults from the RMP. Also, relationships between backward and forward error recovery are not considered. Some RMP examples are given, and a particular RMP implementation is described. >

A system architecture for fault tolerance in concurrent software

This paper describes the patient record manager and the workflow toolset of the wireless-based e-health system Ward-In-Hand, developed in a European IST (Information Society Technologies) project and currently in use within three hospital wards, in Italy, Spain and Germany. The lack of homogeneity in the healthcare organisations required a suitable implementation of workflow automation tools to create and manage the execution of the care-giving processes, customising them to local ward needs. Solutions for this problem, as well as the integration of the workflow organiser (to be used by individual health professionals during their daily activities) with the patient record manager are discussed.

A mobile e-health system based on workflow automation tools

In this paper the behavior of a MANET when, for several reasons, the node density varies in such a way to cause subnet disconnections, is considered. Data replication is usually employed to avoid data loss in case of unwanted disconnection of a node, increasing its availability. Considering a time-scale connectivity and node mobility, replicas can be distributed over the net, in order to make data available even during disconnection periods.A formula can be derived, which allows to evaluate the replica availability in different scenarios, using the probability density functions describing the partitioning of a network obtained by a simulator. Applying this formula to different kind of networks, it is possible to tune the degree of replication desired for different scenarios, looking for a trade-off between space occupancy and availability gain.

Data replication effectiveness in mobile ad-hoc networks

Recent advancements in the field of social networking, Web 2.0 technologies, grid and cloud computing, and mobile communications have significantly changed many concepts at the basis of e-learning. The latter is also a valuable tool for teaching in developing Countries, especially when jointly used with satellites allowing to overcome the digital divide. In this perspective, this paper investigates several enabling technologies that can be used to improve e learning platforms, reflecting in the so-called e-learning 2.0 and m-learning. Specifically, this work showcases: i) the mobile paradigm applied to e-learning process; ii) the usage of p2p to better exploit the more “social” nature of modern frameworks; iii) the adoption of cloud computing concepts to bring e-learning services to the nextstep and iv) hazards and opportunities when employing satellite communication.

Vittoria Gianuzzi

Papers

Mobile computing in a hospital: the WARD-IN-HAND project

A system architecture for fault tolerance in concurrent software

A mobile e-health system based on workflow automation tools

Data replication effectiveness in mobile ad-hoc networks

Opportunities, integration and issues of applying new technologies over e-learning platforms