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Yau K.-L.A.,Sunway University | Poh G.-S.,University Malaysia of Computer Science and Engineering | Chien S.F.,MIMOS | Al-Rawi H.A.A.,Sunway University
Scientific World Journal | Year: 2014

Cognitive radio (CR) enables unlicensed users to exploit the underutilized spectrum in licensed spectrum whilst minimizing interference to licensed users. Reinforcement learning (RL), which is an artificial intelligence approach, has been applied to enable each unlicensed user to observe and carry out optimal actions for performance enhancement in a wide range of schemes in CR, such as dynamic channel selection and channel sensing. This paper presents new discussions of RL in the context of CR networks. It provides an extensive review on how most schemes have been approached using the traditional and enhanced RL algorithms through state, action, and reward representations. Examples of the enhancements on RL, which do not appear in the traditional RL approach, are rules and cooperative learning. This paper also reviews performance enhancements brought about by the RL algorithms and open issues. This paper aims to establish a foundation in order to spark new research interests in this area. Our discussion has been presented in a tutorial manner so that it is comprehensive to readers outside the specialty of RL and CR. © 2014 Kok-Lim Alvin Yau et al.


Mohamad M.S.,MIMOS | Poh G.S.,University Malaysia of Computer Science and Engineering
Conference Proceedings - Cryptology 2014: Proceedings of the 4th International Cryptology and Information Security Conference 2014 | Year: 2014

This work presents a combined encryption, signature and multisignature scheme with joint security. The motivation lies in a scenario where a personnel in an organisation is required to sign documents individually, and at times involved in a group signing. Our combined scheme attending to the above concerns is based on the joint security notions proposed by Haber and Pinkas, and more recently by Paterson et al, and uses the same key pair for CS-Lite encryption scheme, Okamoto signature scheme and Ma-Weng-Li-Deng multisignature scheme.


Nge C.-E.,University of Malaya | Gan C.-Y.,University Malaysia of Computer Science and Engineering | Ting K.-N.,University of Nottingham Malaysia Campus | Low Y.-Y.,University of Malaya | Kam T.-S.,University of Malaya
Organic Letters | Year: 2014

Two new indole alkaloids characterized by previously unencountered natural product skeletons, viz., criofolinine (1), incorporating a pyrroloazepine motif within a pentacyclic ring system, and vernavosine (2, isolated as its ethyl ether derivative 3, which on hydrolysis regenerated the putative precursor alkaloid 2), incorporating a pyridopyrimidine moiety embedded within a pentacyclic carbon framework, were isolated from a Malayan Tabernaemontana species. The structures and absolute configuration of these alkaloids were determined on the basis of NMR and MS analysis and confirmed by X-ray diffraction analysis. © 2014 American Chemical Society.


Lee W.-K.,University Tunku Abdul Rahman | Goi B.-M.,University Tunku Abdul Rahman | Phan R.C.-W.,Multimedia University | Poh G.-S.,University Malaysia of Computer Science and Engineering
2014 International Symposium on Intelligent Signal Processing and Communication Systems, ISPACS 2014 | Year: 2014

Recently, GPU is widely accepted in research community as an effective accelerator to many existing algorithms. In this paper, we contribute to the cryptography research community by presenting high speed implementation of symmetric block ciphers in GPU platform. We implemented Camellia, CAST5 and SEED in NVIDIA GTX680 and present the details of implementation techniques together with benchmarking results against existing solutions. According to the evaluation result, we are able to achieve throughput of 61.1 Gbps, 45.5 Gbps and 47.4 Gbps for Camellia, CAST5 and SEED accordingly, without considering the data transfer between CPU and GPU. By considering the data transfer, the throughput for Camellia, CAST5 and SEED dropped to 44.9 Gbps, 40.5 Gbps and 38.6 Gbps accordingly. © 2014 IEEE.


Tan S.-Y.,Multimedia University | Chin J.-J.,Multimedia University | Poh G.-S.,University Malaysia of Computer Science and Engineering | Kam Y.H.S.,Multimedia University | Yau W.-C.,Multimedia University
2015 5th International Conference on IT Convergence and Security, ICITCS 2015 - Proceedings | Year: 2015

Searchable encryption is a cryptographic primitive that allows a user to confidentially store items on an outside server and grants the user the capability to search for any particular item that is stored without the server or any third party observers learning anything with regards to the item that is being searched for. In 2006, Curtmola et al. strengthened the security notions for symmetric-key searchable encyrption (SSE) and proposed two secure constructions that utilize only a conventional symmetric-key encryption scheme such as Advanced Encryption Standard (AES). In this work, we show a client-server prototype implementation of the adaptive-secure scheme by Curtmola et al. utilizing only open source software on both client and server side. We show that our implementation runs in reasonable time and provides confidential search functions as defined by SSE schemes. © 2015 IEEE.


Bello O.,University Malaysia Sarawak | Zen H.,University Malaysia Sarawak | Othman A.-K.,University Malaysia Sarawak | Hamid K.A.,University Malaysia of Computer Science and Engineering
Journal of Computer Science | Year: 2015

This paper proposes a utility-based scheduling framework for efficient differentiation of users' Quality-of-Service (QoS) in a broadband wireless access system involving heterogeneous mixed traffic flows. The utility-based scheduling framework, called Maximum QoS Satisfaction (MQS), is based on three novel Radio Resource Allocation (RRA) techniques; delay-based scheduling policy for Real-Time (RT), minimumrate- based scheduling policy for Non-Real-Time (NRT) and a throughputbased scheduling policy for Best-Effort (BE) services. Simulation study shows that MQS achieves superior performances in terms of average system throughput and user satisfaction both in single and heterogeneous mixed traffic scenarios, when compared to some existing ones. © 2015 Olalekan Bello, Hushairi Zen, AL-Khalid Othman and Khairuddin Abdul Hamid.


Gan C.-Y.,University Malaysia of Computer Science and Engineering | Yoganathan K.,Agency for Science, Technology and Research Singapore | Sim K.-S.,University of Malaya | Low Y.-Y.,University of Malaya | And 2 more authors.
Phytochemistry | Year: 2014

Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo. © 2014 Elsevier Ltd. All rights reserved.


Wong S.-P.,University of Malaya | Gan C.-Y.,University Malaysia of Computer Science and Engineering | Lim K.-H.,University of Nottingham Malaysia Campus | Ting K.-N.,University of Nottingham Malaysia Campus | And 2 more authors.
Organic Letters | Year: 2015

A new monoterpene indole alkaloid characterized by an unprecedented pentacyclic cage skeleton, arboridinine (1), was isolated from a Malaysian Kopsia species. The structure and absolute configuration of the alkaloid were determined based on NMR, MS, and X-ray diffraction analysis. A possible biogenetic pathway from a pericine precursor is presented. © 2015 American Chemical Society.


Yap W.-S.,University of Malaya | Gan C.-Y.,University Malaysia of Computer Science and Engineering | Sim K.-S.,University of Malaya | Lim S.-H.,University of Malaya | And 2 more authors.
Journal of Natural Products | Year: 2016

Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells. © 2015 The American Chemical Society and American Society of Pharmacognosy.


PubMed | University Malaysia of Computer Science and Engineering
Type: Journal Article | Journal: Journal of natural products | Year: 2016

Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.

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