- Computing and Information Systems - Research Publications
Computing and Information Systems - Research Publications
Permanent URI for this collection
Search Results
Now showing
1 - 10 of 17
-
ItemA voting approach to identify a small number of highly predictive genes using multiple classifiersHassan, MR ; Hossain, MM ; Bailey, J ; Macintyre, G ; Ho, JWK ; Ramamohanarao, K (BMC, 2009-01-30)BACKGROUND: Microarray gene expression profiling has provided extensive datasets that can describe characteristics of cancer patients. An important challenge for this type of data is the discovery of gene sets which can be used as the basis of developing a clinical predictor for cancer. It is desirable that such gene sets be compact, give accurate predictions across many classifiers, be biologically relevant and have good biological process coverage. RESULTS: By using a new type of multiple classifier voting approach, we have identified gene sets that can predict breast cancer prognosis accurately, for a range of classification algorithms. Unlike a wrapper approach, our method is not specialised towards a single classification technique. Experimental analysis demonstrates higher prediction accuracies for our sets of genes compared to previous work in the area. Moreover, our sets of genes are generally more compact than those previously proposed. Taking a biological viewpoint, from the literature, most of the genes in our sets are known to be strongly related to cancer. CONCLUSION: We show that it is possible to obtain superior classification accuracy with our approach and obtain a compact gene set that is also biologically relevant and has good coverage of different biological processes.
-
ItemA novel document ranking method using the discrete cosine transformPark, LAF ; Palaniswami, M ; Ramamohanarao, K (IEEE COMPUTER SOC, 2005-01)We propose a new Spectral text retrieval method using the Discrete Cosine Transform (DCT). By taking advantage of the properties of the DCT and by employing the fast query and compression techniques found in vector space methods (VSM), we show that we can process queries as fast as VSM and achieve a much higher precision.
-
ItemA taxonomy of data grids for distributed data sharing, management, and processingVenugopal, S ; Buyya, R ; Ramamohanarao, K (Association for Computing Machinery (ACM), 2006)Data Grids have been adopted as the next generation platform by many scientific communities that need to share, access, transport, process, and manage large data collections distributed worldwide. They combine high-end computing technologies with high-performance networking and wide-area storage management techniques. In this article, we discuss the key concepts behind Data Grids and compare them with other data sharing and distribution paradigms such as content delivery networks, peer-to-peer networks, and distributed databases. We then provide comprehensive taxonomies that cover various aspects of architecture, data transportation, data replication and resource allocation, and scheduling. Finally, we map the proposed taxonomy to various Data Grid systems not only to validate the taxonomy but also to identify areas for future exploration.
-
ItemProtecting SIP Server from CPU-Based DoS Attacks using History-Based IP FilteringZhou, CV ; Leckie, C ; Ramamohanarao, K (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2009-10)
-
ItemPatterns based classifiersRamamohanarao, K ; Fan, H (SPRINGER, 2007-03)
-
ItemSurvey of network-based defense mechanisms countering the DoS and DDoS problemsPeng, T ; Leckie, C ; Ramamohanarao, K (ASSOC COMPUTING MACHINERY, 2007-04)This article presents a survey of denial of service attacks and the methods that have been proposed for defense against these attacks. In this survey, we analyze the design decisions in the Internet that have created the potential for denial of service attacks. We review the state-of-art mechanisms for defending against denial of service attacks, compare the strengths and weaknesses of each proposal, and discuss potential countermeasures against each defense mechanism. We conclude by highlighting opportunities for an integrated solution to solve the problem of distributed denial of service attacks.
-
ItemInformation sharing for distributed intrusion detection systemsPeng, T ; Leckie, C ; Ramamohanarao, K (ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2007-08)
-
ItemIncremental maintenance of shortest distance and transitive closure in first-order logic and SQLPang, CY ; Dong, GZ ; Ramamohanarao, K (ASSOC COMPUTING MACHINERY, 2005-09)Given a database, the view maintenance problem is concerned with the efficient computation of the new contents of a given view when updates to the database happen. We consider the view maintenance problem for the situation when the database contains a weighted graph and the view is either the transitive closure or the answer to the all-pairs shortest-distance problem ( APSD ). We give incremental algorithms for APSD , which support both edge insertions and deletions. For transitive closure, the algorithm is applicable to a more general class of graphs than those previously explored. Our algorithms use first-order queries, along with addition (+) and less-than (<) operations ( FO (+,<)); they store O ( n 2 ) number of tuples, where n is the number of vertices, and have AC 0 data complexity for integer weights. Since FO (+,<) is a sublanguage of SQL and is supported by almost all current database systems, our maintenance algorithms are more appropriate for database applications than nondatabase query types of maintenance algorithms.
-
ItemTrust-based robust scheduling and runtime adaptation of scientific workflowWang, M ; Ramamohanarao, K ; Chen, J (WILEY, 2009-11)
-
ItemBuilding more robust multi-agent systems using a log-based approachUnruh, A ; Bailey, J ; Ramamohanarao, K (IOS Press, 2009-03-23)