Veljko Milutinovic

Routing and security in mobile ad hoc networks

Mobile ad hoc networks remove the dependence on a fixed network infrastructure by treating every available mobile node as an intermediate switch, thereby extending the range of mobile nodes well beyond that of their base transceivers. We present four manet routing algorithms along with a hybrid approach, discuss their advantages and disadvantages, and describe security problems inherent in such networks.

Hardware approaches to cache coherence in shared-memory multiprocessors, Part 1

Improving performance and scalability in shared-memory multiprocessors requires an appropriate solution to the well-known cache coherence problem. Hardware schemes-highly convenient because of their transparency for software-offer fully dynamic solutions, with an ability to achieve high performance. In Part 1 of this two-part series, we discussed the principles of the two major groups of hardware protocols and summarized relevant representatives. Here, we also briefly consider the coherence problem in multilevel cache hierarchies and large-scale, shared-memory multiprocessors.<<ETX>>

A survey of distributed shared memory systems

Distributed shared memory (DSM) systems have attracted considerable research efforts recently, since they combine the advantages of two different computer classes: shared memory multiprocessors and distributed systems. The most important one is the use of shared memory programming paradigm on physically distributed memories. One possible classification taxonomy, which includes two basic criteria and a number of related characteristic, is proposed and described. According to the basic classification criteria-implementation level of DSM mechanism-systems are organized into three groups: hardware, software, and hybrid DSM implementations. The paper also presents an almost exhaustive survey of the existing solutions in an uniform manner, presenting their DSM mechanisms and issues of importance for various DSM systems and approaches.<<ETX>>

A survey of heterogeneous computing: concepts and systems

This survey of heterogeneous computing concepts and systems is based on the recently proposed by the authors EM/sup 3/ (Execution Modes/Machine Models) taxonomy of computer systems in general. The taxonomy is based on two criteria: the number of execution modes supported by the system and the number of machine models present in the system. Since these two criteria are orthogonal, four classes exist: Single Execution mode/Single machine Model (SESM), Single Execution modes/Multiple machine Models (SEMM), Multiple Execution modes/Single machine Model (MESM), and Multiple Execution modes/Multiple machine Models (MEMM). In Section II, heterogeneous computing concepts are viewed through three phases of the compilation and execution of any heterogeneous application: parallelism detection, parallelism characterization and resource allocation. Parallelism detection phase discovers fine-grain parallelism inside every task. This phase is not an exclusive feature of heterogeneous computing, so it will not be dealt with in greater detail. The assignment of parallelism characterization phase is to estimate the behavior of each task in the application on every architecture in the heterogeneous system. In the parallelism characterization domain, one original taxonomy is given. This taxonomy contains scheme classes such as vector and matrix static and dynamic, implicit and explicit, algorithmic and heuristic and numeric and symbolic. Resource allocation phase determines the place and the moment for execution of every task to optimize certain performance measure related to some criteria. In the resource allocation domain, the existing Casavant-Kuhl taxonomy is extended and used. This well known taxonomy is supplemented with scheme classes such as noncooperative competitive, noncooperative noncompetitive, and load sharing. In Section III, heterogeneous systems characterized with multiple execution modes (fully heterogeneous systems falling in the MESM and the MEMM class) are surveyed. The MESM class systems are described and illustrated with three case studies, two of which support SIMD/MIMD and one supports scalar/vector combination of execution modes. The MEMM class systems are described and illustrated with two representative examples of fully heterogeneous networks supporting multiple execution modes. The system software for heterogeneous computing systems is presented according to an original three-dimensional (3-D) taxonomy whose criteria rely on the level of heterogeneity support implementation, the programming approach, and the data access technique applied. In Section III, several representative heterogeneous applications are described with their computation requirements and the systems used for their execution. Each topic covered in the paper contains several concise examples.

Mobile agents and Java mobile agents toolkits

This paper gives an overview of what mobile agents are, what they should do, and how they can be implemented in Java. Why Java? The choice to concentrate on Java is evoked by many existing solutions in Java that handles architectural heterogeneity between communicating machines on the net. It seems to be the best available language for making mobile agents roam through the Internet for the time being.

A survey of software solutions for maintenance of cache consistency in shared memory multiprocessors

Presents a comprehensive survey of software solutions for the maintenance of cache consistency in shared-memory multiprocessor systems. The lack of widely known, acceptably systematic, and flexible classification in this research field has been our basic motivation for this work. We have proposed a classification based on a set of ten carefully selected criteria that we considered most relevant. Existing solutions have been described and decomposed on the basis of this classification. Different solutions correspond to various points of an abstract multidimensional criterion-space. Such generalized approach enables the points corresponding to nonexistent but potentially useful solutions to be noticed and selected for exploration.<<ETX>>

An overview of reflective memory systems

Reflective memory systems are an effective solution to problems raised by message passing in multicomputer environments. The authors provide an overview of existing and emerging RM systems and offer a forecast of future trends.

Mobile Agents and Java Mobile Agents Toolkits

This paper gives an overview of what the mobile agents are, what they should do and how they can be implemented in Java. Why Java? The choice to concentrate on Java is evoked by many existing solutions in Java that handles architectural heterogeneity between communicating machines on the net. It seems to be the best available language for making mobile agents roaming through the Internet for the time being.