Currently, users interact with computer systems at the level of applications or devices. In the reality of ubiquitous computing it is neither acceptable nor scalable to expect that users keep track of all their activi...
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ISBN:
(纸本)3540204989
Currently, users interact with computer systems at the level of applications or devices. In the reality of ubiquitous computing it is neither acceptable nor scalable to expect that users keep track of all their activities, explicitly migrate them, and configure resources as they need them. We conceptualize a user environment as an aggregation of the whole activity of a user in a ubiquitous system. In this paper we define a user environment in a ubiquitous system. We also propose a software architecture that maintains user environments, deploys and adjusts them to underlying computing spaces, as necessary.
FAIR Digital Object (FDO) is an emerging concept that is highlighted by European Open Science Cloud (EOSC) as a potential candidate for building an ecosystem of machine-actionable research outputs. In this work we sys...
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FAIR Digital Object (FDO) is an emerging concept that is highlighted by European Open Science Cloud (EOSC) as a potential candidate for building an ecosystem of machine-actionable research outputs. In this work we systematically evaluate FDO and its implementations as a global distributed object system, by using five different conceptual frameworks that cover interoperability, middleware, FAIR principles, EOSC requirements and FDO guidelines themself. We compare the FDO approach with established Linked Data practices and the existing Web architecture, and provide a brief history of the Semantic Web while discussing why these technologies may have been difficult to adopt for FDO purposes. We conclude with recommendations for both Linked Data and FDO communities to further their adaptation and alignment.
Java has an important role in building distributed object oriented web enabled applications. In the article an analysis of two distributed object models in context of Java language is presented. Several aspects of RMI...
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Java has an important role in building distributed object oriented web enabled applications. In the article an analysis of two distributed object models in context of Java language is presented. Several aspects of RMI and CORBA such as features, maturity, support for legacy, systems, learning curve and ease of development are compared. A special emphasis is given to the performances. Different testing scenarios give a complete overview about real world performances of both architectures. Based on the comparison results, recommendations for selecting the most appropriate architecture for a given problem domain are presented. Therefore the paper contributes to the understanding of the distributed object architectures and to the study of Java RMI and CORBA performances.
In the past 20 years, Network and Systems Management (N&SM) has thrived on mostly centralized or weakly distributed paradigms. Advances in technologies and software engineering suggested new ways of doing N&SM...
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In the past 20 years, Network and Systems Management (N&SM) has thrived on mostly centralized or weakly distributed paradigms. Advances in technologies and software engineering suggested new ways of doing N&SM. The computational object approach is one of the main management technologies that have recently appeared. Based on this approach, the architecture proposed in this paper uses programming concepts instead of protocol concepts and conceals protocol complexity by easily manipulated components. Concerning the information model, the Common Information Model (CIM) is used which is designed in an object-oriented manner that is the key behind scalable N&*** implementation is done in the Windows environment and using the C++ programming language.
This paper describes a set of tools and a methodology intended to implement distributed real-time systems based on a network of microcontroled boards. Using inexpensive yet powerful microcontrollers and other componen...
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This paper describes a set of tools and a methodology intended to implement distributed real-time systems based on a network of microcontroled boards. Using inexpensive yet powerful microcontrollers and other components, systems composed by a number of intelligent sensors, actuators, and controllers can be developed using the concept of active objects. The proposal consists of microcontroled boards running the μClinux operating system, which is an embedded version of Linux, a CAN network, a publisher/subscriber communication model, and the SIMOO-RT tool, which is used for modeling, simulation and code generation.
Metadata harvesting requires timely propagation of up-to-date information from thousands of Repositories over a wide area network. It is desirable to keep the data as fresh as possible while observing the overhead on ...
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We describe several order relations for group cooperative applications. Our goal is to define the main interleaving semantics existing in distributed object environments with group invocations and variable sharing. We...
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We describe several order relations for group cooperative applications. Our goal is to define the main interleaving semantics existing in distributed object environments with group invocations and variable sharing. We generalize the Lamport's Happened-before relation defined for message passing applications to a causal relation between actions or methods in object world. Next, we precise a set of order properties for group method invocations. It includes the local, causal and total ordering deduced from the similar ordering in message broadcast protocols, and causally coherent and serializable transactions deduced from the concurrency control. Finally, we present two implementations of one of these order property on distributed object systems GUIDE and CORBA.
This paper introduces a data-warehousing framework that is designed in the context of distributed objects;thus it has the benefits of scalability, interoperability, and support for heterogeneous environments. The prop...
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This paper introduces a data-warehousing framework that is designed in the context of distributed objects;thus it has the benefits of scalability, interoperability, and support for heterogeneous environments. The proposed framework adopts an efficient incremental lightweight view maintenance technique that is motivated by the fact that different views in a Data Warehouse (DW) can have different freshness requirements. This fact can be used to enhance the view maintenance performance in huge DWs by installing the source updates only when the freshness constraints are violated and only the DW views that have the violated constraints. The proposed view maintenance strategy guarantees strong consistency for each view and doesn't the DW sources to be quiescent in order to complete the view maintenance.
Current tendency in software development of large control systems Icads to products built up from components working in different nodes of a heterogeneous network environment. Particular components becomes an importan...
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Current tendency in software development of large control systems Icads to products built up from components working in different nodes of a heterogeneous network environment. Particular components becomes an important aspect, since a program composed of components does not guarantee in itself reliable function after the system is extended or a component is replaced. To ensure the system reliability, it is necessary to create a middleware layer. which is able to guarantee a reliable cooperation of components in a heterogeneous distributed environment at application design level. The present paper describes an approach to the design of configurable software architecture focused in the field of control systems. It introduces the technical realization of the middleware layer for reliable and predictable collaboration of components in a distributed heterogeneous industrial environment
Object-based parallel and distributed applications are becoming increasingly popular, driven by the programmability advantages of component technology and a flat shared-object space. However, the flat shared-object sp...
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ISBN:
(纸本)9781581132380
Object-based parallel and distributed applications are becoming increasingly popular, driven by the programmability advantages of component technology and a flat shared-object space. However, the flat shared-object space introduces a performance challenge: applications that rely on the transparent coherent caching of objects achieve high performance only on tightly coupled parallel machines. In distributed environments, the overheads of object caching force application designers to choose other solutions. Consequently, most applications sacrifice programmability, relying instead on either the explicit coherence management of cached objects, or on vastly different middleware abstractions such as multicast and *** this paper, we describe object views — language support for efficient object caching in parallel and distributed computations. Object views specify restrictions on how computation threads can use an object, providing the underlying implementation with information about the potential side effects of object access, and thereby enabling construction of scalable, low-overhead caching protocols customized to application requirements. We present extensions to the Java programming language for expressing object views, and describe the design and implementation of a translator and run-time system for executing view-augmented Java programs on a distributed cluster of workstations. Experimental results based on a shared whiteboard application demonstrate that view-based object caching can achieve performance superior to multicast- and event-based implementations, while retaining essentially a shared object interface.
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