1999
Journal article
Restricted
Parallelising the Mean Value Analysis algorithm
Gennaro C, King Pjb
The Mean Value Analysis (MVA) algorithm is one of the most popular for evaluating the performance of separable (or product form) queueing networks. Although its complexity is modest when jobs are indistinguishable, the introduction of different customer classes rapidly increases its computational cost. The problems of parallelising the algorithm while retaining its conceptual simplicity are examined. In particular, a parallel implementation of MVA on a distributed memory machine is developed using the MPI library for communication.Source: TRANSACTIONS OF THE SOCIETY FOR COMPUTER SIMULATION, vol. 16 (issue 1), pp. 16-22
DOI: 10.1177/003754979907200304
Metrics:
Gennaro C, King Pjb
The Mean Value Analysis (MVA) algorithm is one of the most popular for evaluating the performance of separable (or product form) queueing networks. Although its complexity is modest when jobs are indistinguishable, the introduction of different customer classes rapidly increases its computational cost. The problems of parallelising the algorithm while retaining its conceptual simplicity are examined. In particular, a parallel implementation of MVA on a distributed memory machine is developed using the MPI library for communication.Source: TRANSACTIONS OF THE SOCIETY FOR COMPUTER SIMULATION, vol. 16 (issue 1), pp. 16-22
DOI: 10.1177/003754979907200304
Metrics:
See at:
SIMULATION 
| CNR IRIS | CNR IRIS | sim.sagepub.com
2002
Journal article
Restricted
Integrated Performance Models for SPMD Applications and MIMD Architectures
Cremonesi P, Gennaro C
This paper introduces queuing network models for the performance analysis of SPMD applications executed on generalpurpose parallel architectures such as MIMD and clusters of workstations. The models are based on the pattern of computation, communication, and I/O operations of typical parallel applications. Analysis of the models leads to the definition of speedup surfaces which capture the relative influence of processors and I/O parallelism and show the effects of different hardware and software components on the performance. Since the parameters of the models correspond to measurable program and hardware characteristics, the models can be used to anticipate the performance behavior of a parallel application as a function of the target architecture (i.e., number of processors, number of disks, I/O topology, etc).Source: IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS (PRINT), vol. 13 (issue 12), pp. 1320-1332
DOI: 10.1109/tpds.2002.1158268
DOI: 10.1109/tpds.2002.1019862
Metrics:
Cremonesi P, Gennaro C
This paper introduces queuing network models for the performance analysis of SPMD applications executed on generalpurpose parallel architectures such as MIMD and clusters of workstations. The models are based on the pattern of computation, communication, and I/O operations of typical parallel applications. Analysis of the models leads to the definition of speedup surfaces which capture the relative influence of processors and I/O parallelism and show the effects of different hardware and software components on the performance. Since the parameters of the models correspond to measurable program and hardware characteristics, the models can be used to anticipate the performance behavior of a parallel application as a function of the target architecture (i.e., number of processors, number of disks, I/O topology, etc).Source: IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS (PRINT), vol. 13 (issue 12), pp. 1320-1332
DOI: 10.1109/tpds.2002.1158268
DOI: 10.1109/tpds.2002.1019862
Metrics:
See at:
IEEE Transactions on Parallel and Distributed Systems | IEEE Transactions on Parallel and Distributed Systems | CNR IRIS | ieeexplore.ieee.org | CNR IRIS
2003
Conference article
Restricted
Similarity Join in Metric Spaces Using eD-Index
Dohnal V, Gennaro C, Zezula P
Similarity join in distance spaces constrained by the metric postulates is the necessary complement of more famous similarity range and the nearest neighbor search primitives. However, the quadratic computational complexity of similarity joins prevents from applications on large data collections. We present the eD-Index, an extension of D-index, and we study an application of the eDIndex to implement two algorithms for similarity self joins, i.e. the range query join and the overloading join. Though also these approaches are not able to eliminate the intrinsic quadratic complexity of similarity joins, significant performance improvements are confirmed by experiments.DOI: 10.1007/978-3-540-45227-0_48
Metrics:
Dohnal V, Gennaro C, Zezula P
Similarity join in distance spaces constrained by the metric postulates is the necessary complement of more famous similarity range and the nearest neighbor search primitives. However, the quadratic computational complexity of similarity joins prevents from applications on large data collections. We present the eD-Index, an extension of D-index, and we study an application of the eDIndex to implement two algorithms for similarity self joins, i.e. the range query join and the overloading join. Though also these approaches are not able to eliminate the intrinsic quadratic complexity of similarity joins, significant performance improvements are confirmed by experiments.DOI: 10.1007/978-3-540-45227-0_48
Metrics:
2005
Journal article
Restricted
Similarity Grid for searching in metric spaces
Batko M, Gennaro C, Zezula P
Similarity search in metric spaces represents an important paradigm for content-based retrieval of many applications. Existing centralized search structures can speed-up retrieval, but they do not scale up to large volume of data because the response time is linearly increasing with the size of the searched file. The proposed GHT* index is a scalable and distributed structure. By exploiting parallelism in a dynamic network of computers, the GHT* achieves practically constant search time for similarity range queries in data-sets of arbitrary size. The structure also scales well with respect to the growing volume of retrieved data. Moreover, a small amount of replicated routing information on each server increases logarithmically. At the same time, the potential for interquery parallelism is increasing with the growing data-sets because the relative number of servers utilized by individual queries is decreasing. All these properties are verified by experiments on a prototype system using real-life data-sets.DOI: 10.1007/11549819_3
Metrics:
Batko M, Gennaro C, Zezula P
Similarity search in metric spaces represents an important paradigm for content-based retrieval of many applications. Existing centralized search structures can speed-up retrieval, but they do not scale up to large volume of data because the response time is linearly increasing with the size of the searched file. The proposed GHT* index is a scalable and distributed structure. By exploiting parallelism in a dynamic network of computers, the GHT* achieves practically constant search time for similarity range queries in data-sets of arbitrary size. The structure also scales well with respect to the growing volume of retrieved data. Moreover, a small amount of replicated routing information on each server increases logarithmically. At the same time, the potential for interquery parallelism is increasing with the growing data-sets because the relative number of servers utilized by individual queries is decreasing. All these properties are verified by experiments on a prototype system using real-life data-sets.DOI: 10.1007/11549819_3
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2008
Journal article
Restricted
Regia: a metadata editor for audiovisual documents
Gennaro C
Although the Metadata Editor is an important part of any digital library, it becomes fundamental in the presence of audiovisual content. This is because the metadata produced by automated support tools (such as speech recognizers and shot detection procedures) is error-prone and often needs correction. In addition, scenes are manually annotated. This paper describes Regia, a prototype application for manually editing metadata for audiovisual documents developed in the ECHO project. Regia allows the user to manually edit textual metadata and to hierarchically organize the segmentation of the audiovisual content. An important feature of this metadata editor is that it is not hard-wired with a particular metadata attributes set. To achieve this feature the XML schema of the metadata model is used by the editor as a configuration file.Source: MULTIMEDIA TOOLS AND APPLICATIONS, vol. 36 (issue 3), pp. 185-201
DOI: 10.1007/s11042-007-0129-4
Metrics:
Gennaro C
Although the Metadata Editor is an important part of any digital library, it becomes fundamental in the presence of audiovisual content. This is because the metadata produced by automated support tools (such as speech recognizers and shot detection procedures) is error-prone and often needs correction. In addition, scenes are manually annotated. This paper describes Regia, a prototype application for manually editing metadata for audiovisual documents developed in the ECHO project. Regia allows the user to manually edit textual metadata and to hierarchically organize the segmentation of the audiovisual content. An important feature of this metadata editor is that it is not hard-wired with a particular metadata attributes set. To achieve this feature the XML schema of the metadata model is used by the editor as a configuration file.Source: MULTIMEDIA TOOLS AND APPLICATIONS, vol. 36 (issue 3), pp. 185-201
DOI: 10.1007/s11042-007-0129-4
Metrics:
See at:
Multimedia Tools and Applications | CNR IRIS | CNR IRIS | www.springerlink.com
2004
Journal article
Open Access
GHT*: a Peer-to-Peer System for Metric Data
Batko M, Gennaro C, Zezula P
GHT* is a scalable and distributed similarity search structure that has been specifically designed to support metric space objects. Our structure is based on the P2P communication paradigm and it is scalable in that it distributes the data over more and more independent peer computers. By exploiting parallelism in a dynamic network of computers, the query execution scales up very well considering both the number of distance computations and the hop count between the peers. Updates are performed locally and a node splitting never requires sending multiple messages to many peers.Source: ERCIM NEWS, vol. 59, pp. 65-66
Batko M, Gennaro C, Zezula P
GHT* is a scalable and distributed similarity search structure that has been specifically designed to support metric space objects. Our structure is based on the P2P communication paradigm and it is scalable in that it distributes the data over more and more independent peer computers. By exploiting parallelism in a dynamic network of computers, the query execution scales up very well considering both the number of distance computations and the hop count between the peers. Updates are performed locally and a node splitting never requires sending multiple messages to many peers.Source: ERCIM NEWS, vol. 59, pp. 65-66
See at:
CNR IRIS 
| www.ercim.eu | CNR IRIS
2002
Conference article
Restricted
A Metric Index for Approximate Text Management
Dohnal V, Gennaro C, Zezula P
Text collections of data need not only search support for identical objects, but the approximate matching is even more important. A suitable metric to such a task is the edit distance measure. However, the quadratic computational complexity of edit distance prevents from applying naive storage organizations, such as the sequential search, and more sophisticated search structures must be applied. We have investigated the properties of the D-index to approximate searching and matching in text databases. The experiments confirm a very good performance for retrieving close objects and sub-linear scalability to process large files. Even the similarity joins can be performed efficiently.
Dohnal V, Gennaro C, Zezula P
Text collections of data need not only search support for identical objects, but the approximate matching is even more important. A suitable metric to such a task is the edit distance measure. However, the quadratic computational complexity of edit distance prevents from applying naive storage organizations, such as the sequential search, and more sophisticated search structures must be applied. We have investigated the properties of the D-index to approximate searching and matching in text databases. The experiments confirm a very good performance for retrieving close objects and sub-linear scalability to process large files. Even the similarity joins can be performed efficiently.
See at:
dblp.uni-trier.de | CNR IRIS | CNR IRIS
2008
Conference article
Restricted
A content-addressable network for similarity join in metric spaces
Gennaro C
Similarity join is an interesting complement of the well-established similarity range and nearest neighbors search primitives in metric spaces. However, the quadratic computational complexity of similarity join prevents from applications on large data collections. We present MCAN+, an extension of MCAN (a Content-Addressable Network for metric objects) to support similarity self join queries. The challenge of the proposed approach is to address the problem of the intrinsic quadratic complexity of similarity joins, with the aim of limiting the elaboration time, by involving an increasing number of computational nodes as the dataset size grows. To test the scalability of MCAN+, we used a real-life dataset of color features extracted from one million images of the Flickr photo sharing website.
Gennaro C
Similarity join is an interesting complement of the well-established similarity range and nearest neighbors search primitives in metric spaces. However, the quadratic computational complexity of similarity join prevents from applications on large data collections. We present MCAN+, an extension of MCAN (a Content-Addressable Network for metric objects) to support similarity self join queries. The challenge of the proposed approach is to address the problem of the intrinsic quadratic complexity of similarity joins, with the aim of limiting the elaboration time, by involving an increasing number of computational nodes as the dataset size grows. To test the scalability of MCAN+, we used a real-life dataset of color features extracted from one million images of the Flickr photo sharing website.
See at:
dl.acm.org | CNR IRIS | CNR IRIS
2008
Conference article
Restricted
A methodology for building and querying an ontology representing data and multimedia sources
Beneventano D, Gennaro C, Guerra F
Managing data and multimedia sources with a unique tool is a challenging issue. In this paper, the capabilities of the MOMIS integration system and the MILOS multimedia content management system are coupled, thus providing a methodology and a tool for building and querying a populated ontology representing data and multimedia sources.
Beneventano D, Gennaro C, Guerra F
Managing data and multimedia sources with a unique tool is a challenging issue. In this paper, the capabilities of the MOMIS integration system and the MILOS multimedia content management system are coupled, thus providing a methodology and a tool for building and querying a populated ontology representing data and multimedia sources.
2003
Other
Open Access
Scalable and Distributed Similarity Search in Metric Spaces
Batko M, Gennaro C, Zezula P
In this paper we propose a new access structure, called GHT*, based on generalized hyperplane tree (GHT) and distributed dynamic hashing (DDH) techniques. GHT* is a distributed structure which allows to perform range search in a metric space according to a distance function d. The structure does not require a central directory and it is able to gracefully scale through splits of one bucket at a time.
Batko M, Gennaro C, Zezula P
In this paper we propose a new access structure, called GHT*, based on generalized hyperplane tree (GHT) and distributed dynamic hashing (DDH) techniques. GHT* is a distributed structure which allows to perform range search in a metric space according to a distance function d. The structure does not require a central directory and it is able to gracefully scale through splits of one bucket at a time.
See at:
CNR IRIS | ISTI Repository | CNR IRIS
2004
Other
Open Access
A Scalable Nearest Neighbor Search in P2P Systems
Batko M, Gennaro C, Zezula P
Similarity search in metric spaces represents an important paradigm for content-based retrieval of many applications. Existing centralized search structures can speed-up retrieval, but they do not scale up to large volume of data because the response time is linearly increasing with the size of the searched file. In this article, we study the problem of executing the nearest neighbor(s) queries in a distributed metric structure, which is based on the P2P communication paradigm and the generalized hyperplane partitioning. By exploiting parallelism in a dynamic network of computers, the query execution scales up very well considering both the number of distance computations and the hop count between the peers. Results are verified by experiments on real-life data sets.
Batko M, Gennaro C, Zezula P
Similarity search in metric spaces represents an important paradigm for content-based retrieval of many applications. Existing centralized search structures can speed-up retrieval, but they do not scale up to large volume of data because the response time is linearly increasing with the size of the searched file. In this article, we study the problem of executing the nearest neighbor(s) queries in a distributed metric structure, which is based on the P2P communication paradigm and the generalized hyperplane partitioning. By exploiting parallelism in a dynamic network of computers, the query execution scales up very well considering both the number of distance computations and the hop count between the peers. Results are verified by experiments on real-life data sets.
See at:
CNR IRIS | ISTI Repository | CNR IRIS
2008
Contribution to book
Restricted
Efficiency and scalability issues in metric access methods
Dohal V D, Gennaro C, Zezula P
The metric space paradigm has recently received attention as an important model of similarity in the area of Bioinformatics. Numerous techniques have been proposed to solve similarity (range or nearest-neighbor) queries on collections of data from metric domains. Though important representatives are outlined, this chapter is not trying to substitute existing comprehensive surveys. The main objective is to explain and prove by experiments that similarity searching is typically an expensive process which does not easily scale to very large volumes of data, thus distributed architectures able to exploit parallelism must be employed.Source: STUDIES IN COMPUTATIONAL INTELLIGENCE (PRINT), pp. 235-263
DOI: 10.1007/978-3-540-75767-2_12
Metrics:
Dohal V D, Gennaro C, Zezula P
The metric space paradigm has recently received attention as an important model of similarity in the area of Bioinformatics. Numerous techniques have been proposed to solve similarity (range or nearest-neighbor) queries on collections of data from metric domains. Though important representatives are outlined, this chapter is not trying to substitute existing comprehensive surveys. The main objective is to explain and prove by experiments that similarity searching is typically an expensive process which does not easily scale to very large volumes of data, thus distributed architectures able to exploit parallelism must be employed.Source: STUDIES IN COMPUTATIONAL INTELLIGENCE (PRINT), pp. 235-263
DOI: 10.1007/978-3-540-75767-2_12
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.springerlink.com
2003
Software
Metadata Only Access
Regia: a metadata editor for Audio/Video Document developed within the EU ECHO project
Gennaro C
Regia is a metadata editor for Audio/Video Document developed within the EU ECHO project. Regia generally works connected to the ECHO Digital Library System, which unfortunately is not available anymore. However, the program is also able to work in standalone modality. The metadata model of ECHO is based on the IFLA model, a general conceptual framework used to describe heterogeneous digital media resources. This metadata model is composed of four levels describing different aspects of intellectual or artistic endeavour: AVDocument, Expression, Media, and Storage. The entities of the model are organized in a structure that reflects the hierarchical order of the entities from the top level (work) to the bottom (item). Figure 1 shows a schematic representation of the ECHO Metadata Model. As it is possible to see, the metadata which belong to different classes comprised in the model, are logically divided in two sets Bibliographic Metadata and Time/Space related Metadata. This classification is also reflected in the Metadata Editor interface.
Gennaro C
Regia is a metadata editor for Audio/Video Document developed within the EU ECHO project. Regia generally works connected to the ECHO Digital Library System, which unfortunately is not available anymore. However, the program is also able to work in standalone modality. The metadata model of ECHO is based on the IFLA model, a general conceptual framework used to describe heterogeneous digital media resources. This metadata model is composed of four levels describing different aspects of intellectual or artistic endeavour: AVDocument, Expression, Media, and Storage. The entities of the model are organized in a structure that reflects the hierarchical order of the entities from the top level (work) to the bottom (item). Figure 1 shows a schematic representation of the ECHO Metadata Model. As it is possible to see, the metadata which belong to different classes comprised in the model, are logically divided in two sets Bibliographic Metadata and Time/Space related Metadata. This classification is also reflected in the Metadata Editor interface.
See at:
CNR IRIS
2009
Conference article
Open Access
Scalable similarity self join in a metric DHT system
Gennaro C
Efficient processing of similarity joins is important for a large class of data analysis and data-mining applications. This primitive finds all pairs of records within a predefined distance threshold of each other. We present MCAN+, an extension of MCAN (a Content-Addressable Network for metric objects) to support similarity self join queries. The challenge of the proposed approach is to address the problem of the intrinsic quadratic complexity of similarity joins, with the aim of bounding the elaboration time, by involving an increasing number of computational nodes as the dataset size grows. To test the scalability of MCAN+, we used a real-life dataset of color features extracted from one million images of the Flickr photo sharing website.
Gennaro C
Efficient processing of similarity joins is important for a large class of data analysis and data-mining applications. This primitive finds all pairs of records within a predefined distance threshold of each other. We present MCAN+, an extension of MCAN (a Content-Addressable Network for metric objects) to support similarity self join queries. The challenge of the proposed approach is to address the problem of the intrinsic quadratic complexity of similarity joins, with the aim of bounding the elaboration time, by involving an increasing number of computational nodes as the dataset size grows. To test the scalability of MCAN+, we used a real-life dataset of color features extracted from one million images of the Flickr photo sharing website.
2005
Other
Open Access
Regia: a metadata editor for audiovisual documents
Gennaro C
Although the Metadata Editor is an important part of any digital library, it becomes fundamental in the presence of audiovisual content. This is because the metadata produced by automated support tools (such as speech recognizers and shot detection procedures) is error-prone and often needs correction. In addition, scenes are manually annotated. This paper describes Regia, a prototype application for manual editing metadata for audiovisual documents developed in the ECHO project. Regia allows the user to manually edit textual metadata and to hierarchically organize the segmentation of the audiovisual content. An important feature of this metadata editor is that it is not hard--wired with a particular metadata attributes set; for this purpose the XML schema of the metadata model is used by the editor as configuration file.
Gennaro C
Although the Metadata Editor is an important part of any digital library, it becomes fundamental in the presence of audiovisual content. This is because the metadata produced by automated support tools (such as speech recognizers and shot detection procedures) is error-prone and often needs correction. In addition, scenes are manually annotated. This paper describes Regia, a prototype application for manual editing metadata for audiovisual documents developed in the ECHO project. Regia allows the user to manually edit textual metadata and to hierarchically organize the segmentation of the audiovisual content. An important feature of this metadata editor is that it is not hard--wired with a particular metadata attributes set; for this purpose the XML schema of the metadata model is used by the editor as configuration file.
See at:
CNR IRIS | ISTI Repository | CNR IRIS
2001
Other
Open Access
Integrated performance models for SPMD applications and MIMD architectures
Cremonesi P, Gennaro C
The report introduces queuing network models for the performance analysis of SPMD applications executed on general-purpose parallel architectures such as MIMD and clusters of workstations. The models are based on the pattern of computation, communication and I/O operations of typical parallel applications. Analysis of the models leads to the definition of speedup surfaces which capture the relative influence of processors and I/O parallelism and show the effects of different hardware and software components on the performance. Since the parameters of the models correspond to measurable program and hardware characteristics, the models can be used to predict the performance of parallel applications in early stages of software development.
Cremonesi P, Gennaro C
The report introduces queuing network models for the performance analysis of SPMD applications executed on general-purpose parallel architectures such as MIMD and clusters of workstations. The models are based on the pattern of computation, communication and I/O operations of typical parallel applications. Analysis of the models leads to the definition of speedup surfaces which capture the relative influence of processors and I/O parallelism and show the effects of different hardware and software components on the performance. Since the parameters of the models correspond to measurable program and hardware characteristics, the models can be used to predict the performance of parallel applications in early stages of software development.
2009
Other
Open Access
A theoretical approach to the self similarity join in a distributed enviroment
Gennaro C
Efficient processing of similarity joins is important for a large class of data analysis and data-mining applications. This primitive finds all pairs of records within a predefined distance threshold of each other. However, most of the existing approaches have been based on spatial join techniques designed primarily for data in a vector space. Treating data collections as metric objects brings a great advantage in generality, because a single metric technique can be applied to many specific search problems quite different in nature. In this paper, we concentrate our attention on a special form of join, the Self Similarity Join, which retrieves pairs from the same dataset. In particular, we consider the case in which the dataset is split into subsets that are searched for self similarity join independently (e.g, in a distributed computing environment). To this end, we formalize the abstract concept of epsilon-Cover, prove its correctness, and demonstrate its effectiveness by applying it to two real implementations on a real-life large dataset.
Gennaro C
Efficient processing of similarity joins is important for a large class of data analysis and data-mining applications. This primitive finds all pairs of records within a predefined distance threshold of each other. However, most of the existing approaches have been based on spatial join techniques designed primarily for data in a vector space. Treating data collections as metric objects brings a great advantage in generality, because a single metric technique can be applied to many specific search problems quite different in nature. In this paper, we concentrate our attention on a special form of join, the Self Similarity Join, which retrieves pairs from the same dataset. In particular, we consider the case in which the dataset is split into subsets that are searched for self similarity join independently (e.g, in a distributed computing environment). To this end, we formalize the abstract concept of epsilon-Cover, prove its correctness, and demonstrate its effectiveness by applying it to two real implementations on a real-life large dataset.
See at:
CNR IRIS | ISTI Repository | CNR IRIS
2003
Journal article
Restricted
Effective Scheduling of Detached Rules in Active Databases
S Ceri, C Gennaro, S Paraboschi, G Serazzi
While triggers have become a classical ingredient of relational database systems, research in active databases is aiming at extending the functionality and expressive power of active rules beyond the scope of relational triggers. One of the most important current trend concerns the support of detached active rules, i.e., of rules which are executed as separate transactions, running outside of the scope of the transaction which generates the triggering event. Detached rules have important applications in workflow management and global integrity maintenance across transactions. One of the main issues in designing the rule engine for detached rules is determining their optimal scheduling. In this paper, we study the performance of a detached rule scheduler whose objective is to minimize the interference of detached rule execution with regard to the normal transactional load. This objective is achieved by executing detached rules at given periods of time and by assigning them a fixed amount of dedicated threads; we study the performance of the scheduler relative to the two most critical design parameters, the frequency of execution of the scheduler, and the number of dedicated execution threads.Source: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING (PRINT), vol. 15, pp. 2-13
DOI: 10.1109/tkde.2003.1161578
Metrics:
S Ceri, C Gennaro, S Paraboschi, G Serazzi
While triggers have become a classical ingredient of relational database systems, research in active databases is aiming at extending the functionality and expressive power of active rules beyond the scope of relational triggers. One of the most important current trend concerns the support of detached active rules, i.e., of rules which are executed as separate transactions, running outside of the scope of the transaction which generates the triggering event. Detached rules have important applications in workflow management and global integrity maintenance across transactions. One of the main issues in designing the rule engine for detached rules is determining their optimal scheduling. In this paper, we study the performance of a detached rule scheduler whose objective is to minimize the interference of detached rule execution with regard to the normal transactional load. This objective is achieved by executing detached rules at given periods of time and by assigning them a fixed amount of dedicated threads; we study the performance of the scheduler relative to the two most critical design parameters, the frequency of execution of the scheduler, and the number of dedicated execution threads.Source: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING (PRINT), vol. 15, pp. 2-13
DOI: 10.1109/tkde.2003.1161578
Metrics:
See at:
IEEE Transactions on Knowledge and Data Engineering | CNR IRIS | ieeexplore.ieee.org | CNR IRIS
1998
Conference article
Restricted
I/O performance in hybrid MIMD+SIMD machines
Cremonesi P, Gennaro C, Marega R
Sommario non disponibile.DOI: 10.1007/bfb0037196
Metrics:
Cremonesi P, Gennaro C, Marega R
Sommario non disponibile.DOI: 10.1007/bfb0037196
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.scopus.com
1999
Conference article
Restricted
Performance models for I/O bound SPMD applications on clusters of workstations
Gennaro C
Clusters of workstations represent today a satisfactory alternative to MPPs and supercomputers in many areas of application. The rapidly reduction of the cost of high performance workstations/PCs makes this technology ever more available. Moreover, new concepts for the integration of individual workstations through Local Area Networks are emerging. High speed interconnection networks and optimized protocol system architectures are the most important objectives of current research in this field of study. In this contribution, we attempt to propose a simple but effective performance model of systems with distributed computational and I/O resources when executing parallel scientific applications characterized by communication bursts and by intensive I/O phases. By means of queueing network techniques, the analysis of the model leads to the definition of a speedup surface which captures the relative influence of processors and disks parallelism in the performance of applications that alternates computations and I/O operations in a cyclic fashion.DOI: 10.1109/empdp.1999.746686
Metrics:
Gennaro C
Clusters of workstations represent today a satisfactory alternative to MPPs and supercomputers in many areas of application. The rapidly reduction of the cost of high performance workstations/PCs makes this technology ever more available. Moreover, new concepts for the integration of individual workstations through Local Area Networks are emerging. High speed interconnection networks and optimized protocol system architectures are the most important objectives of current research in this field of study. In this contribution, we attempt to propose a simple but effective performance model of systems with distributed computational and I/O resources when executing parallel scientific applications characterized by communication bursts and by intensive I/O phases. By means of queueing network techniques, the analysis of the model leads to the definition of a speedup surface which captures the relative influence of processors and disks parallelism in the performance of applications that alternates computations and I/O operations in a cyclic fashion.DOI: 10.1109/empdp.1999.746686
Metrics:
See at:
doi.org | CNR IRIS | CNR IRIS | www.computer.org