Balazs Goldschmidt | Budapest University of Technology and Economics (original) (raw)

Papers by Balazs Goldschmidt

Computer Science and Information Systems, 2004

Abstract. Adaptation ,in multimedia ,systems ,is usually ,restricted to defensive, reactive media... more Abstract. Adaptation ,in multimedia ,systems ,is usually ,restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves,not less attention. If a distributed multimedia ,system ,cares for overall, end-to-end quality of service then it should provide a meaningful combination,of both. Weintroduce,an adaptive ,multimedia ,server (ADMS) and ,a supporting middleware which implement offensive adaptation

Proceedings of the 24th Iasted International Conference on Internet and Multimedia Systems and Applications, 2006

Distributed applications, like video-on-demand services, require QoS provision. When using applic... more Distributed applications, like video-on-demand services, require QoS provision. When using applications comprising dynamically reconfigurable modules, the demands can be provided by the proactive deployment of the components. In this paper we introduce SWARMLAN, a language that can describe the communication connections and demands of a general class of distributed applications. Although there are several languages developed for describing QoS needs of applications, they are direct in the sense, that they are able only to describe the actual demands and connection of the components. Our language is intended to describe the template of the connections, and the actual deployment and QoS demand can be provided for each concrete case individually. Moreover, the results produced by the compiled code can be used to decide about the optimal future deployment of components.

Pdpta, 2006

In online multimedia systems resources (e.g. network capacity) are to be evenly distributed among... more In online multimedia systems resources (e.g. network capacity) are to be evenly distributed among clients. These clients, however, usually have different QoS needs, and thus their actual capacity demands may vary considerably. In such context even distribution is not possible, but fair distribution, based on subjective client satisfaction must be achived instead. In this paper a new metric, exponential scarcity, is proposed, that's based on clients' subjective quality experience. It is shown, that a resource distirbution, where this metric is minimal leads to a balanced subjective satisfaction of the clients. As a corollary, the ideal scaling of QoS variations of multimedia content is proposed.

In many places and in different fields of applications continuous experiments are being made to i... more In many places and in different fields of applications continuous experiments are being made to integrate complex systems on a SOA basis. Assuming that the market will remain diversified on the long term, the key to the widespread distribution of SOA is the interoperability among products of different vendors. Authors introduce a demo framework aiming to compare different SOA products and to assess their cooperation. Authors also describe their experiences showing that without the appropriate settings and non-functional requirements seamless interoperability can not be achieved. Authors reveal the causes, and emphasize the necessity for further standardization that might enable the out-ofbox interoperability and portability of SOA tools.

Distributed and Parallel Systems, 2002

This paper introduces a mobile agent-based infrastructure for an adaptive multi-media server enab... more This paper introduces a mobile agent-based infrastructure for an adaptive multi-media server enabling a dynamic migration or replication of certain multimedia applications among a set of available server nodes. It discusses the requirements from both, the server’s and the middleware’s point of view to each other and comes up with a specification and implementation of a CORBA-based interface between them.

A CORBA-based infrastructure for an adaptive multimedia server is introduced, enabling dynamic mi... more A CORBA-based infrastructure for an adaptive multimedia server is introduced, enabling dynamic migration or replication of certain multimedia applications among a set of available server nodes. The requirements from both the server's and the middleware's point of view are discussed. A specification of a CORBA interface and a corresponding implementation is presented. Finally, as a proof of concept, measurements of the implementation are shown and discussed. The measurements show the importance of the related servers' distribution on the network.

Computer Science and Information Systems, 2004

The pattern community came about from a consciously crafted culture, a culture that has persisted... more The pattern community came about from a consciously crafted culture, a culture that has persisted, grown, and arguably thrived for a decade. The culture was built on a small number of explicit principles. The culture became embodied in its activities-conferences called PLoPs that centered on a social activity for reviewing technical works-and in a body of literature that has wielded broad influence on software design. Embedded within the larger culture of software development, the pattern culture has enjoyed broad influence on software development worldwide. The culture hasn?t been without its problems: conflict with academic culture, accusations of cultism, and compromises with other cultures. However, its culturally rich principles still live on both in the original organs of the pattern community and in the activities of many other software communities worldwide.

The basic building blocks of SOA systems are web services. The domain specific language SOAL deve... more The basic building blocks of SOA systems are web services. The domain specific language SOAL developed by the authors has a Java and C#-like syntax for describing web service interfaces. Beside the syntax a metamodel (SoaMM) is also defined. The paper introduces an extended version of both SOAL and SoaMM that supports WS-Policy specifications. The original WS-Policy standards specify huge XML descriptions that are too complex and low level for efficient service design. The metamodel presented provides a high abstraction level that is still strong enough for generating vendor-specific service configurations for WCF and major JAX-WS implementations.

The purpose of this paper is to present a new infrastructure for multimedia database searches tha... more The purpose of this paper is to present a new infrastructure for multimedia database searches that is based on CORBA and mobile agent technology. A new mobile agent system, called Vagabond, was implemented in pure Java using only standard CORBA facilities. The fundamental agent design and architecture is introduced here. Measurements demonstrated the merits of Vagabond, namely the simple design, the implicit heterogenity inherited from CORBA, and its speed. The system (renamed as ¢ ¡ ) was implanted inside an Oracle8i database system which is able to run Java code as a stored procedure. Further measurements have justified the idea presented above, ie. sending agents directly inside the database can decrease the response time of multimedia content search and retrieval. However, the required modifications made the embedded agency accessible for clients using only Aurora, Oracle's modified Visibroker ORB. On the basis of the Proxy design pattern, the paper presents a proxy solution that encapsulates the specific protocol issues that restricted interoperability, and thus provides the user of the infrastructure with the benefits of a truly heterogeneous environment.

In a distributed server architecture an obvious question is where to deploy the components. Host ... more In a distributed server architecture an obvious question is where to deploy the components. Host recommendation, which gives the answer, faces problems such as server selection, host deployment and, in case of multimedia servers, video replication. It is especially relevant for the Adaptive Distributed Multimedia Server (ADMS) which is dynamically able to add and remove its components to different nodes of the network. The present survey paper introduces the different variants of host recom-mendation and gives an overview of its possible mathematical approaches. Emphasis is put on the facility location problem and the related approxi-mation algorithms. Finally some algorithms selected for implementation are presented.

Parallel and Distributed Processing Techniques and Applications, 2006

In online multimedia systems resources (e.g. network capa city) are to be evenly distributed amon... more In online multimedia systems resources (e.g. network capa city) are to be evenly distributed among clients. These clients, however, usually have differ ent QoS needs, and thus their actual capacity demands may vary considerably. In such contexteven distribution is not possible, but fair distribution, based on subjective client satisfaction must be achived ins tead. In this paper a new metric,exponential

Lecture Notes in Computer Science, 2003

Multimedia services are becoming widespread, while the network capacity can not keep up with the ... more Multimedia services are becoming widespread, while the network capacity can not keep up with the growth of user demands. Usually proxies are used to overcome the QoS degradation. One of the fundamental problems of applying proxies is to recognize the relevant set of proxy placement criteria, and to find a good algorithm. In this paper we propose a greedy algorithm

Lecture Notes in Computer Science, 2014

Periodica Polytechnica Electrical Engineering and Computer Science, 2014

Web services provide platform independent communication through an XML-based standard family. The... more Web services provide platform independent communication through an XML-based standard family. The major software vendors released their own SOA products implementing these standards. However, the configuration of the WS-* protocols differs from product to product. Matching these configurations between different products can be a tedious task. In addition, security protocols are complicated to configure, especially if access control is also required. Although the XACML standard aims to solve this problem, its rules and policies described in XML are not user friendly, and XACML has little support in the major SOA products. Therefore, we have developed a platform independent metamodel for describing distributed systems of web services. From models described in this metamodel the platform specific configurations and program code can be generated for the various SOA products, increasing the productivity of the development. This article introduces an access control extension to this metamodel.

Communications in Computer and Information Science, 2010

The basic building blocks of SOA systems are web services. WSDL, the standard language for defini... more The basic building blocks of SOA systems are web services. WSDL, the standard language for defining web services, is far too complex and redundant to be efficiently handled by humans. Existing solutions use either graphical representations (UML, etc.), which are again inefficient in large scale projects, or define web services in the implementation’s native language, which is a bottom-up approach risking interface stability. Both lack support for concepts like conditions, access-rights, etc. The domain specific language introduced in this paper uses a Java and C#-like language for describing web service interfaces. It has the same descriptive power as WSDL while maintaining simplicity and readability. Examples show how to use the language, and how it can be compiled into WSDL.

IEEE Transactions on Services Computing, 2014

Computer Science and Information Systems, 2004

Abstract. Adaptation ,in multimedia ,systems ,is usually ,restricted to defensive, reactive media... more Abstract. Adaptation ,in multimedia ,systems ,is usually ,restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves,not less attention. If a distributed multimedia ,system ,cares for overall, end-to-end quality of service then it should provide a meaningful combination,of both. Weintroduce,an adaptive ,multimedia ,server (ADMS) and ,a supporting middleware which implement offensive adaptation

Proceedings of the 24th Iasted International Conference on Internet and Multimedia Systems and Applications, 2006

Distributed applications, like video-on-demand services, require QoS provision. When using applic... more Distributed applications, like video-on-demand services, require QoS provision. When using applications comprising dynamically reconfigurable modules, the demands can be provided by the proactive deployment of the components. In this paper we introduce SWARMLAN, a language that can describe the communication connections and demands of a general class of distributed applications. Although there are several languages developed for describing QoS needs of applications, they are direct in the sense, that they are able only to describe the actual demands and connection of the components. Our language is intended to describe the template of the connections, and the actual deployment and QoS demand can be provided for each concrete case individually. Moreover, the results produced by the compiled code can be used to decide about the optimal future deployment of components.

Pdpta, 2006

In online multimedia systems resources (e.g. network capacity) are to be evenly distributed among... more In online multimedia systems resources (e.g. network capacity) are to be evenly distributed among clients. These clients, however, usually have different QoS needs, and thus their actual capacity demands may vary considerably. In such context even distribution is not possible, but fair distribution, based on subjective client satisfaction must be achived instead. In this paper a new metric, exponential scarcity, is proposed, that's based on clients' subjective quality experience. It is shown, that a resource distirbution, where this metric is minimal leads to a balanced subjective satisfaction of the clients. As a corollary, the ideal scaling of QoS variations of multimedia content is proposed.

In many places and in different fields of applications continuous experiments are being made to i... more In many places and in different fields of applications continuous experiments are being made to integrate complex systems on a SOA basis. Assuming that the market will remain diversified on the long term, the key to the widespread distribution of SOA is the interoperability among products of different vendors. Authors introduce a demo framework aiming to compare different SOA products and to assess their cooperation. Authors also describe their experiences showing that without the appropriate settings and non-functional requirements seamless interoperability can not be achieved. Authors reveal the causes, and emphasize the necessity for further standardization that might enable the out-ofbox interoperability and portability of SOA tools.

Distributed and Parallel Systems, 2002

This paper introduces a mobile agent-based infrastructure for an adaptive multi-media server enab... more This paper introduces a mobile agent-based infrastructure for an adaptive multi-media server enabling a dynamic migration or replication of certain multimedia applications among a set of available server nodes. It discusses the requirements from both, the server’s and the middleware’s point of view to each other and comes up with a specification and implementation of a CORBA-based interface between them.

A CORBA-based infrastructure for an adaptive multimedia server is introduced, enabling dynamic mi... more A CORBA-based infrastructure for an adaptive multimedia server is introduced, enabling dynamic migration or replication of certain multimedia applications among a set of available server nodes. The requirements from both the server's and the middleware's point of view are discussed. A specification of a CORBA interface and a corresponding implementation is presented. Finally, as a proof of concept, measurements of the implementation are shown and discussed. The measurements show the importance of the related servers' distribution on the network.

Computer Science and Information Systems, 2004

The pattern community came about from a consciously crafted culture, a culture that has persisted... more The pattern community came about from a consciously crafted culture, a culture that has persisted, grown, and arguably thrived for a decade. The culture was built on a small number of explicit principles. The culture became embodied in its activities-conferences called PLoPs that centered on a social activity for reviewing technical works-and in a body of literature that has wielded broad influence on software design. Embedded within the larger culture of software development, the pattern culture has enjoyed broad influence on software development worldwide. The culture hasn?t been without its problems: conflict with academic culture, accusations of cultism, and compromises with other cultures. However, its culturally rich principles still live on both in the original organs of the pattern community and in the activities of many other software communities worldwide.

The basic building blocks of SOA systems are web services. The domain specific language SOAL deve... more The basic building blocks of SOA systems are web services. The domain specific language SOAL developed by the authors has a Java and C#-like syntax for describing web service interfaces. Beside the syntax a metamodel (SoaMM) is also defined. The paper introduces an extended version of both SOAL and SoaMM that supports WS-Policy specifications. The original WS-Policy standards specify huge XML descriptions that are too complex and low level for efficient service design. The metamodel presented provides a high abstraction level that is still strong enough for generating vendor-specific service configurations for WCF and major JAX-WS implementations.

The purpose of this paper is to present a new infrastructure for multimedia database searches tha... more The purpose of this paper is to present a new infrastructure for multimedia database searches that is based on CORBA and mobile agent technology. A new mobile agent system, called Vagabond, was implemented in pure Java using only standard CORBA facilities. The fundamental agent design and architecture is introduced here. Measurements demonstrated the merits of Vagabond, namely the simple design, the implicit heterogenity inherited from CORBA, and its speed. The system (renamed as ¢ ¡ ) was implanted inside an Oracle8i database system which is able to run Java code as a stored procedure. Further measurements have justified the idea presented above, ie. sending agents directly inside the database can decrease the response time of multimedia content search and retrieval. However, the required modifications made the embedded agency accessible for clients using only Aurora, Oracle's modified Visibroker ORB. On the basis of the Proxy design pattern, the paper presents a proxy solution that encapsulates the specific protocol issues that restricted interoperability, and thus provides the user of the infrastructure with the benefits of a truly heterogeneous environment.

In a distributed server architecture an obvious question is where to deploy the components. Host ... more In a distributed server architecture an obvious question is where to deploy the components. Host recommendation, which gives the answer, faces problems such as server selection, host deployment and, in case of multimedia servers, video replication. It is especially relevant for the Adaptive Distributed Multimedia Server (ADMS) which is dynamically able to add and remove its components to different nodes of the network. The present survey paper introduces the different variants of host recom-mendation and gives an overview of its possible mathematical approaches. Emphasis is put on the facility location problem and the related approxi-mation algorithms. Finally some algorithms selected for implementation are presented.

Parallel and Distributed Processing Techniques and Applications, 2006

In online multimedia systems resources (e.g. network capa city) are to be evenly distributed amon... more In online multimedia systems resources (e.g. network capa city) are to be evenly distributed among clients. These clients, however, usually have differ ent QoS needs, and thus their actual capacity demands may vary considerably. In such contexteven distribution is not possible, but fair distribution, based on subjective client satisfaction must be achived ins tead. In this paper a new metric,exponential

Lecture Notes in Computer Science, 2003

Multimedia services are becoming widespread, while the network capacity can not keep up with the ... more Multimedia services are becoming widespread, while the network capacity can not keep up with the growth of user demands. Usually proxies are used to overcome the QoS degradation. One of the fundamental problems of applying proxies is to recognize the relevant set of proxy placement criteria, and to find a good algorithm. In this paper we propose a greedy algorithm

Lecture Notes in Computer Science, 2014

Periodica Polytechnica Electrical Engineering and Computer Science, 2014

Web services provide platform independent communication through an XML-based standard family. The... more Web services provide platform independent communication through an XML-based standard family. The major software vendors released their own SOA products implementing these standards. However, the configuration of the WS-* protocols differs from product to product. Matching these configurations between different products can be a tedious task. In addition, security protocols are complicated to configure, especially if access control is also required. Although the XACML standard aims to solve this problem, its rules and policies described in XML are not user friendly, and XACML has little support in the major SOA products. Therefore, we have developed a platform independent metamodel for describing distributed systems of web services. From models described in this metamodel the platform specific configurations and program code can be generated for the various SOA products, increasing the productivity of the development. This article introduces an access control extension to this metamodel.

Communications in Computer and Information Science, 2010

The basic building blocks of SOA systems are web services. WSDL, the standard language for defini... more The basic building blocks of SOA systems are web services. WSDL, the standard language for defining web services, is far too complex and redundant to be efficiently handled by humans. Existing solutions use either graphical representations (UML, etc.), which are again inefficient in large scale projects, or define web services in the implementation’s native language, which is a bottom-up approach risking interface stability. Both lack support for concepts like conditions, access-rights, etc. The domain specific language introduced in this paper uses a Java and C#-like language for describing web service interfaces. It has the same descriptive power as WSDL while maintaining simplicity and readability. Examples show how to use the language, and how it can be compiled into WSDL.

IEEE Transactions on Services Computing, 2014