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Displaying 1-50 out of 54 total
A Case for Peering of Content Delivery Networks
Found in: IEEE Distributed Systems Online
By Rajkumar Buyya, Al-Mukaddim Khan Pathan, James Broberg, Zahir Tari
Issue Date:October 2006
pp. 3
The authors present a model for an open, scalable, and service-oriented architecture (SOA)-based system. This system helps to create open Content and Service Delivery Networks that scale well and can share resources with other CSDNs through cooperation and...
 
Guest Editors' Introduction: Special Section on Semantic Issues of Multimedia Systems
Found in: IEEE Transactions on Knowledge and Data Engineering
By Zahir Tari, Robert Meersman
Issue Date:May 2001
pp. 335-336
No summary available.
 
Cache Management in CORBA Distributed Object Systems
Found in: IEEE Concurrency
By Zahir Tari, Herry Hamidjaja, Qi Tang Lin
Issue Date:July 2000
pp. 48-55
<p>For many distributed data-intensive applications, the default remote invocation of CORBA objects by clients is not acceptable because of performance degradation. Caching lets clients invoke operations locally on distributed objects instead of fetc...
 
ADAPT-POLICY: Task Assignment in Server Farms when the Service Time Distributionof Tasks is Not Known A Priori
Found in: IEEE Transactions on Parallel and Distributed Systems
By Malith Jayasinghe,Zahir Tari,Panlop Zeephongsekul,Albert Y. Zomaya
Issue Date:April 2014
pp. 851-861
Service time distribution of certain computing workloads such as static web content is well known. However, for many other computing workloads (e.g., dynamic web content, scientific workloads) the service time distribution is not well understood and it is ...
 
A Framework for Improving the Accuracy of Unsupervised Intrusion Detection for SCADA Systems
Found in: 2013 12th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom)
By Abdulmohsen Almalawi,Zahir Tari,Adil Fahad,Ibrahim Khalil
Issue Date:July 2013
pp. 292-301
Supervisory Control and Data Acquisition (SCADA) systems are a salient part of the control and monitoring of critical infrastructures such as electricity generation, distribution, water treatment and distribution, and gas and oil production. Recently, such...
 
A Spring Based Framework for Verification of Service Composition
Found in: Services Computing, IEEE International Conference on
By Anshuman Mukherjee,Zahir Tari,Peter Bertok
Issue Date:July 2011
pp. 258-265
Service-Oriented architecture (SOA) based applications have assumed widespread acceptance owing to their agility, maintainability and modularity. However, the safety and reliability of such loosely coupled systems entirely depend on the precision of servic...
 
Performance Analysis of Multi-level Time Sharing Task Assignment Policies on Cluster-Based Systems
Found in: Cluster Computing, IEEE International Conference on
By Malith Jayasinghe, Zahir Tari, Panlop Zeephongsekul
Issue Date:September 2010
pp. 265-274
There is extensive evidence indicating that moderncomputer workloads exhibit highly variability in their processing requirements. Under such workloads, traditional task assignment policies do not perform well. Size-based policies perform significantly bett...
 
Multi-level Multi-server Task Assignment with Work-Conserving Migration
Found in: Network Computing and Applications, IEEE International Symposium on
By Malith Jayasinghe, Zahir Tari, Panlop Zeephongsekul
Issue Date:July 2010
pp. 178-181
Size-based task assignment policies have shown significant performance improvements over traditional task assignment policies under highly variable workload conditions. However, these policies are not suitable to assign tasks in time sharing systems. Moreo...
 
A scalable Multi-Tier Task Assignment Policy with Minimum Excess Load
Found in: Computers and Communications, IEEE Symposium on
By Malith Jayasinghe, Zahir Tari, Panlop Zeephongsekul
Issue Date:June 2010
pp. 913-918
Existing task assignment policies designed to schedule highly variable computer workloads are not scalable and they generate large amount of wasted processing. This paper proposes a scalable Multi-Tier Task Assignment Policy with Minimum Excess Load (MTTME...
 
An Analytical Framework for Evaluating Survivability of SCADA Systems
Found in: Computer and Information Technology, International Conference on
By Carlos Queiroz, Abdun Mahmood, Zahir Tari
Issue Date:July 2010
pp. 877-881
Supervisory Control and Data Acquisition (SCADA) systems control and monitor industrial and critical infrastructure functions, such as electricity, gas, water, waste, railway and traffic. Recently, SCADA systems have been targeted by an increasing number o...
 
The Impact of Service Cohesion on the Analyzability of Service-Oriented Software
Found in: IEEE Transactions on Services Computing
By Mikhail Perepletchikov, Caspar Ryan, Zahir Tari
Issue Date:April 2010
pp. 89-103
Service-Oriented Computing (SOC) is intended to improve software maintainability as businesses become more agile and underlying processes and rules change more frequently. However, to date, the impact of service cohesion on the analyzability subcharacteris...
 
Building a SCADA Security Testbed
Found in: Network and System Security, International Conference on
By Carlos Queiroz, Abdun Mahmood, Jiankun Hu, Zahir Tari, Xinghuo Yu
Issue Date:October 2009
pp. 357-364
SCADA (Supervisory Control and Data Acquisition) systems control and monitor industrial and critical infrastructure functions, such as the electricity, gas, water, waste, railway and traffic. Recent attacks on SCADA systems highlight the need of a SCADA se...
 
Modeling of BPEL Composite Services Using Clustered Coloured Petri-Nets
Found in: Services Part II, IEEE Congress on
By Anshuman Mukherjee, Zahir Tari, Peter Bertok
Issue Date:September 2009
pp. 55-62
Client requests often span over several web services and these services have to be invoked in some sequence based on business logic of a composite service. BPEL language is used for specification of web service composition and has become the industry stand...
 
Similarity-Based SOAP Multicast Protocol to Reduce Bandwith and Latency in Web Services
Found in: IEEE Transactions on Services Computing
By Khoi Ahn Phan, Zahir Tari, Peter Bertok
Issue Date:April 2008
pp. 88-103
Web Services technology provided several advantages over other technologies, however it still has serious limitations, including high latency and high protocol overhead. To improve performance, SOAP network traffic needs to be substantially reduced. This p...
 
Matching Strictly Dependent Global Constraints for Composite Web Services
Found in: Web Services, European Conference on
By Nalaka Gooneratne, Zahir Tari, James Harland
Issue Date:November 2007
pp. 139-148
Web service discovery requires matching techniques for comparing and selecting web service descriptions based on user constraints. Semantic-based approaches achieve higher recall than other approaches (such as syntax-based approaches), because they employ ...
 
eSMP: A Multicast Protocol to Minimize SOAP Network Traffic in Low Bandwidth Environments
Found in: Local Computer Networks, Annual IEEE Conference on
By Khoi Anh Phan, Zahir Tari, Peter Bertok
Issue Date:October 2007
pp. 95-106
Web services, which are built on SOAP as the transport protocol, have emerged in recent years as a promising technology to enable interoperability between distributed applications. As such, SOAP may be used to handle a large number of transactions; and con...
 
Coupling Metrics for Predicting Maintainability in Service-Oriented Designs
Found in: Software Engineering Conference, Australian
By Mikhail Perepletchikov, Caspar Ryan, Keith Frampton, Zahir Tari
Issue Date:April 2007
pp. 329-340
Service-Oriented Computing (SOC) is emerging as a promising paradigm for developing distributed enterprise applications. Although some initial concepts of SOC have been investigated in the research literature, and related technologies are in the process of...
 
Optimizing Web Services Performance by Using Similarity-Based Multicast Protocol
Found in: Web Services, European Conference on
By Khoi Anh Phan, Zahir Tari, Peter Bertok
Issue Date:December 2006
pp. 119-128
Web services have emerged as a key technology that enables interoperability between distributed applications. It is desirable that SOAP, being the Web service transport protocol for inter-connecting applications across organizations, performs efficiently i...
 
An Adaptive Membership Algorithm for Application Layer Multicast
Found in: Networking and Services, International conference on
By Bin Rong, Ibrahim Khalil, Zahir Tari
Issue Date:July 2006
pp. 35
Due to deployment difficulty of network layer multicast, application layer multicast is considered to be a good substitute for massive P2P video/audio streaming in large networks. However, in application layer multicast, the participating users join and le...
 
Multipath Aware TCP (MATCP)
Found in: Computers and Communications, IEEE Symposium on
By Peter Dimopoulos, Panlop Zeephongsekul, Zahir Tari
Issue Date:June 2006
pp. 981-988
On the Internet many different paths exist between each source and destination. When single path routing is used these paths can be under utilized, not used fairly or not used at all. One way to overcome this is to allow multipath routing. But when multipl...
 
Efficient SOAP Binding for Mobile Web Services
Found in: Local Computer Networks, Annual IEEE Conference on
By Kwong Yuen Lai, Thi Khoi Anh Phan, Zahir Tari
Issue Date:November 2005
pp. 218-225
<p>Existing web services rely on HTTP and TCP as the underlying transport protocols for SOAP messaging. While these protocols provide a number of benefits, including being able to pass through firewalls and are universally supported across different ...
 
A Gossip-based Membership Management Algorithm for Large-Scale Peer-to-Peer Media Streaming
Found in: Local Computer Networks, Annual IEEE Conference on
By Bin Rong, Ibrahim Khalil, Zahir Tari
Issue Date:November 2005
pp. 486-487
<p>A new adaptive gossip-based membership management algorithm is proposed. Its adaptive nature enables it to con- fine the control overhead to local ranges, and adapt to the ever-changing network traffic conditions and group membership. The random n...
 
A Task-Based Adaptive TTL Approach for Web Server Load Balancing
Found in: Computers and Communications, IEEE Symposium on
By Devarshi Chatterjee, Zahir Tari, Albert Zomaya
Issue Date:June 2005
pp. 877-884
Web sites attracting a high client-traffic cannot simply rely on either mirrored servers or a single server to balance the client-request generated load. DNS load balancing techniques have shown their advantages in dealing with heavy web traffic. These tec...
 
Improving Data Accessibility for Mobile Clients through Cooperative Hoarding
Found in: Data Engineering, International Conference on
By Kwong Yuen Lai, Zahir Tari, Peter Bertok
Issue Date:April 2005
pp. 415-416
In this paper, we introduce the concept of cooperative hoarding to reduce the risks of cache misses for mobile clients. Cooperative hoarding takes advantage of group mobility behaviour, combined with peer cooperation in ad-hoc mode, to improve hoard perfor...
   
Mobility-Aware Cache Replacement for Users of Location-Dependent Services
Found in: Local Computer Networks, Annual IEEE Conference on
By Kwong Yuen Lai, Zahir Tari, Peter Bertok
Issue Date:November 2004
pp. 50-58
Recent advances in wireless communication and global positioning technologies have led to increasing interest in location dependent information services. As mobile users move between locations utilising such services, their access patterns not only exhibit...
 
Modeling the Burstiness of TCP
Found in: Modeling, Analysis, and Simulation of Computer Systems, International Symposium on
By Peter Dimopoulos, Panlop Zeephongsekul, Zahir Tari
Issue Date:October 2004
pp. 175-183
In this paper we investigate the burstiness of the Transmission Control Protocol (TCP) and its impact on a network of finite TCP connections. A detailed TCP and network model is developed to quantify both the burstiness and throughput of TCP connections sh...
 
Reducing Delay with Dynamic Priority RED Queues (DPRQ)
Found in: Modeling, Analysis, and Simulation of Computer Systems, International Symposium on
By Peter Dimopoulos, Panlop Zeephongsekul, Zahir Tari
Issue Date:October 2004
pp. 638-641
A Dynamic Priority RED Queue (DPRQ) algorithm is introduced which combines the core features of weighted round robin (WRR) and priority queues. The DPRQ scheduling algorithm is analytically defined but results so far are limited to simulations with the NS-...
 
An Hoarding Approach for Supporting Disconnected Write Operations in Mobile Environments
Found in: Reliable Distributed Systems, IEEE Symposium on
By Abhinav Vora, Zahir Tari, Peter Bertok
Issue Date:October 2004
pp. 276-288
Caching is one technique that reduces costs and improves performance in mobile environments. It also increases availability during temporary, involuntary disconnections. However, our focus is on voluntary, client initiated disconnections, where hoarding ca...
 
A Role based Access Control for Web Services
Found in: Services Computing, IEEE International Conference on
By Roosdiana Wonohoesodo, Zahir Tari
Issue Date:September 2004
pp. 49-56
Web services are vulnerable to various types of security attacks. This paper addresses one type of attacks, where applications trying to access services to which they are not authorized. Existing access control for web services lack of support for global s...
 
Improving Cache Performance in Mobile Computing Networks through Dynamic Object Relocation
Found in: Parallel and Distributed Systems, International Conference on
By Kwong Yuen Lai, Zahir Tari, Peter Bertok
Issue Date:July 2004
pp. 37
Caching improves the performance of web servers by placing frequently accessed data at intermediate nodes close to web clients. Similarly, in a mobile network, access delay can be reduced by caching data objects near the mobile clients. Existing caching te...
 
Task Assignment Strategy for Overloaded Systems
Found in: Computers and Communications, IEEE Symposium on
By Bin Fu, James Broberg, Zahir Tari
Issue Date:July 2003
pp. 1119
Size-based load distribution approaches are proposed to deal with high variation of task size. One of the most critical problem of these approaches is that they do not consider task deadlines (which if not met may cause task starvation). This paper propose...
 
A Mobile Cache Consistency Protocol Using Shareable Read/Write Time Locks
Found in: Parallel and Distributed Systems, International Conference on
By Abhinav Vora, Zahir Tari, Peter Bertok, Kwong Lai
Issue Date:December 2002
pp. 284
Object caching is often used to improve the performance of mobile applications, but the gain is often lessened by the additional load of maintaining consistency between an original object and its cached copy. This paper aims at reducing the consistency mai...
 
Dynamic Task Assignment in Server Farms: Better Performance by Task Grouping
Found in: Computers and Communications, IEEE Symposium on
By Li ng Tan, Zahir Tari
Issue Date:July 2002
pp. 175
This paper describes a dynamic load balancing approach to distributed server farm systems. This approach overcomes the interference caused by non-negligible very-large tasks in the heavy-tailed distribution. First, a subset of tasks is allocated proportion...
 
Effective Standards for Metadata in the GCMD Data Access System
Found in: Distributed Objects and Applications, International Symposium on
By Omran Bukhres, Zina Ben Miled, Eric Lynch, Lola Olsen, Zahir Tari
Issue Date:September 2000
pp. 155
This paper presents an information retrieval system for use by the Global Change Master Directory. The GCMD is a repository that contains Earth Science data collected by various agencies worldwide. The GCMD does not house the actual data; it contains descr...
 
Dynamic Workflow Management in CORBA Distributed Object Systems
Found in: Software Engineering for Parallel and Distributed Systems, International Symposium on
By Zahir Tari, Vivek Pande
Issue Date:June 2000
pp. 51
We are beginning to see distributed dynamic workflow management systems being implemented using CORBA services. However, these systems do not use events as the mechanism for coordinating workflows. Instead, workflow components use messages to communicate w...
 
A Query Propagation Approach to Improve CORBA Trading Service Scalability
Found in: Distributed Computing Systems, International Conference on
By Zahir Tari, Gregory Craske
Issue Date:April 2000
pp. 504
Existing CORBA traders, at least most of them, support the core functions of the OMG specification of the Trading Service [6]. We believe that this is useful and can help potential users to use such a service in heterogeneous environments. However, we also...
 
A Caching Protocol to Improve CORBA Performance
Found in: Agile Development Conference/Australasian Database Conference
By Stephen Wagner, Zahir Tari
Issue Date:February 2000
pp. 140
For many distributed data intensive applications, the default remote invocation of CORBA objects to a server is not acceptable because of performance degradation. Caching can improve performance and scalability of such applications by increasing the locali...
 
DOK-Trader: A CORBA Persistent Trader with Query Routing Facilities
Found in: Distributed Objects and Applications, International Symposium on
By Greg Craske, Zahir Tari, Kiran R. Kumar
Issue Date:September 1999
pp. 230
Existing traders support the required functions, such as the lookup and register of services. They are limited because they are restricted to a small number of services. This paper proposes solutions to the issues of persistency and query routing in the co...
 
A Role-Based Access Control for Intranet Security
Found in: IEEE Internet Computing
By Zahir Tari, Shun-Wu Chan
Issue Date:September 1997
pp. 24-34
<p>Secure intranets are founded on the protection of logical resources accessible in corporate enterprises. The proposed I-RBAC, role-based access control for intranet security, offers efficient security management based on varied levels of role auth...
 
Correctness-aware high-level functional matching approaches for semantic Web services
Found in: ACM Transactions on the Web (TWEB)
By Islam Elgedawy, James A. Thom, James A. Thom, Zahir Tari, Zahir Tari
Issue Date:April 2008
pp. 1-40
Service matching approaches trade precision for recall, creating the need for users to choose the correct services, which obviously is a major obstacle for automating the service discovery and aggregation processes. Our approach to overcome this problem, i...
     
Cooperative Web Caching using Dynamic Interest-Tagged Filtered Bloom Filters
Found in: IEEE Transactions on Parallel and Distributed Systems
By Holly Alexander,Ibrahim Khalil,Conor Cameron,Zahir Tari,Albert Zomaya
Issue Date:February 2015
pp. 1
Although cooperative Web caching has been widely researched, comparatively little has been done to reduce inter-proxy network overhead whilst allowing for a high percentage of requested documents to be retrieved from the cache. Alleviating these issues can...
 
Granular Evaluation of Anomalies in Wireless Sensor Networks using Dynamic Data Partitioning with an Entropy Criteria
Found in: IEEE Transactions on Computers
By Heshan Kumarage,Ibrahim Khalil,Zahir Tari
Issue Date:February 2015
pp. 1
This paper presents an anomaly detection model that is granular and distributed to accurately and efficiently identify sensed data anomalies within wireless sensor networks. A more decentralised mechanism is introduced with wider use of innetwork processin...
 
Enhancing Availability in Content Delivery Networks for Mobile Platforms
Found in: IEEE Transactions on Parallel and Distributed Systems
By Mahathir Almashor,Ibrahim Khalil,Zahir Tari,Albert Zomaya,Sartaj Sahni
Issue Date:August 2014
pp. 1
Ensuring high data availability is a vital prerogative for Content Delivery Networks (CDN), and as we look to deploy CDN mechanisms onto mobile platforms, this imperative becomes ever more challenging. In traditional CDNs, replication ensures high availabi...
 
Performance Analysis of EDF Scheduling in a Multi-Priority Preemptive M/G/1 Queue
Found in: IEEE Transactions on Parallel and Distributed Systems
By Vidura Gamini Abhaya,Zahir Tari,Panlop Zeephongsekul,Albert Y. Zomaya
Issue Date:August 2014
pp. 2149-2158
This paper presents a queueing theoretic performance model for a multipriority preemptive
 
SCADAVT-A framework for SCADA security testbed based on virtualization technology
Found in: 2013 IEEE 38th Conference on Local Computer Networks (LCN 2013)
By Abdulmohsen Almalawi,Zahir Tari,Ibrahim Khalil,Adil Fahad
Issue Date:October 2013
pp. 639-646
Supervisory Control and Data Acquisition (SCADA) systems monitor and control infrastructures and industrial processes such as smart grid power and water distribution systems. Recently, such systems have been attacked, and traditional security solutions hav...
   
A Property-based Clustering Approach for the CORBA Trading Service
Found in: Distributed Computing Systems, International Conference on
By Gregory Craske, Zahir Tari
Issue Date:June 1999
pp. 0517
The CORBA Trading Service is an object service advertiser for heterogeneous distributed computing environments. Current approaches for the design and implementation of such a CORBA service do not deal with some of the major problems of searching service of...
 
Matching independent global constraints for composite web services
Found in: Proceeding of the 17th international conference on World Wide Web (WWW '08)
By Nalaka Gooneratne, Zahir Tari
Issue Date:April 2008
pp. 1-7
Service discovery employs matching techniques to select services by comparing their descriptions against user constraints. Semantic-based matching approaches achieve higher recall than syntactic-based ones (as they employ ontological reasoning mechanisms t...
     
Verification of web service descriptions using graph-based traversal algorithms
Found in: Proceedings of the 2007 ACM symposium on Applied computing (SAC '07)
By James Harland, Nalaka Gooneratne, Zahir Tari
Issue Date:March 2007
pp. 1385-1392
Service discovery and composition techniques require a careful and accurate specification of the functional and behavioural descriptions of services. Otherwise, the located services may not provide the requested functionality and composite services may inc...
     
Software adaptation for service-oriented systems
Found in: Proceedings of the 1st workshop on Middleware for Service Oriented Computing (MW4SOC 2006) (MW4SOC '06)
By Pablo Rossi, Zahir Tari
Issue Date:November 2006
pp. 12-17
Mobile services operate on hosts with diverse capabilities, in heterogeneous networks, where the usage of resources, such as processor, memory and network, is constantly changing. In order to maintain efficiency, in terms of performance and resource utiliz...
     
A benchmark on soap's transport protocols performance for mobile applications
Found in: Proceedings of the 2006 ACM symposium on Applied computing (SAC '06)
By Khoi Anh Phan, Peter Bertok, Zahir Tari
Issue Date:April 2006
pp. 1139-1144
Handheld mobile devices with wireless capability are gaining popularity. SOAP is a text-based protocol for Web services, but it has high overhead and its suitability for resource-constrained devices over wireless networks needs to be reevaluated. SOAP uses...
     
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