Internal Design of the DSS

This technical report describes the implementation of the DSS middleware with focus on the design of the abstract entity interface and the coordination layer. Key concepts are highlighted and described, on the level of C++ classes

Creating a Distributed Programming System Using the DSS: A Case Study of OzDSS

This technical report describes the integration of the Distribution Subsystem (DSS) to the programming system Mozart. The result, OzDSS, is described in detail. Essential when coupling a programming system to the DSS is how the internal model of threads and language entities are mapped to the abstract entities of the DSS. The model of threads and language entities of Mozart is described at a detailed level to explain the design choices made when developing the code that couples the DSS to Mozart. To show the challenges associated with different thread implementations, the C++DSS system is introduced. C++DSS is a C++ library which uses the DSS to implement different types of distributed language entities in the form of C++ classes. Mozart emulates threads, thus there is no risk of multiple threads accessing the DSS simultaneously. C++DSS, on the other hand, makes use of POSIX threads, thus simultaneous access to the DSS from multiple POSIX threads can happen. The fundamental differences in how threads are treated in a system that emulates threads (Mozart) to a system that make use of native-threads~(C++DSS) is discussed. The paper is concluded by a performance comparison between the OzDSS system and other distributed programming systems. We see that the OzDSS system outperforms ``industry grade'' Java-RMI and Java-CORBA implementations

Generic Distribution Support for Programming Systems

This dissertation provides constructive proof, through the implementation of a middleware, that distribution transparency is practical, generic, and extensible. Fault tolerant distributed services can be developed by using the failure detection abilities of the middleware. By generic we mean that the middleware can be used for many different programming languages and paradigms. Distribution for each kind of language entity is done in terms of consistency protocols, which guarantee that the semantics of the entities are preserved in a distributed setting. The middleware allows new consistency protocols to be added easily. The efficiency of the middleware and the ease of integration are shown by coupling the middleware to a programming system, which encompasses the object oriented, the functional, and the concurrent-declarative programming paradigms. Our measurements show that the distribution middleware is competitive with the most popular distributed programming systems (JavaRMI, .NET, IBM CORBA)

Making the Distribution Subsystem Secure

This report presents how the Distribution Subsystem is made secure. A set of different security threats to a shared data programming system are identifed. The report presents the extensions nessesary to the DSS in order to cope with the identified security threats by maintaining reference security. A reference to a shared data structure cannot be forged or guessed; only by proper delegation can a thread acquire access to data originating at remote processes. Referential security is a requirement for secure distributed applications. By programmatically restricting access to distributed data to trusted nodes, a distributed application can be made secure. However, for this to be true, referential security must be supported on the level of the implementation

Совершенствование организации системы стимулирования труда работников предприятия (на примере ОАО «Гомельский завод литья и нормалей»)

Context-aware services are gaining momentum in mobile computing. To enable rapid development of context-aware services,context information has to be retrieved from the environment, modeled,processed, and distributed to these services. MIDAS is a European research project concerning 3G and beyond, which aims to dene and implement a platform to simplify and speed up the task of developing and deploying mobile applications and services. MIDAS context engine provides mechanisms to retrieve, model, synthesize, and distribute context information in a distributed, mobile environment. This paper presents a way to retrieve and distribute context information using context queries and triggers. A novel approach to perform context synthesis will be presented using operators.QC 20151113</p

Generic Distribution Support for Programming Systems

ii This dissertation provides constructive proof, through the implementation of a middleware, that distribution transparency is practical, generic, and extensible. Fault tolerant distributed services can be developed by using the failure detection abilities of the middleware. By generic we mean that the middleware can be used for many different programming languages and paradigms. Distribution for each kind of language entity is done in terms of consistency protocols, which guarantee that the semantics of the entities are preserved in a distributed setting. The middleware allows new consistency protocols to be added easily. The efficiency of the middleware and the ease of integration are shown by coupling the middleware to a programming system, which encompasses the object oriented, the functional, and the concurrent-declarative programming paradigms. Our measurements show that the distribution middleware is competitive with the most popular distribute

Contents

ISRN:SICS-T–2004/16-S

Context retrieval and distribution in a mobile distributed environment

Context-aware services are gaining momentum in mobile computing. To enable rapid development of context-aware services,context information has to be retrieved from the environment, modeled,processed, and distributed to these services. MIDAS is a European research project concerning 3G and beyond, which aims to dene and implement a platform to simplify and speed up the task of developing and deploying mobile applications and services. MIDAS context engine provides mechanisms to retrieve, model, synthesize, and distribute context information in a distributed, mobile environment. This paper presents a way to retrieve and distribute context information using context queries and triggers. A novel approach to perform context synthesis will be presented using operators.QC 20151113</p

A simulator for tccp in Mozart

The concurrent constraint-programming paradigm, ccp provides convenient synchronisation mechanisms for many distributed algorithms. tccp is defined as a timed extension of ccp usable for reactive systems. We show how tccp can be compiled and interpreted in the distributed multi-paradigm programming system Mozart-Oz