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An efficient multi-channel communications scheme for wireless sensor network
Shariful Islam,Muhammad Mahbub Alam,Choong Seon Hong 한국정보과학회 2010 한국정보과학회 학술발표논문집 Vol.37 No.2B
This paper presents a multi-channel communications system for wireless sensor networks (WSNs), referred to as Load-adaptive practical multi-channel communications (LPMC). LPMC estimates the active load of a channel at the sink, and dynamically adds or removes channel based on the estimated load. The nodes in a path use the same channel; and therefore, they do not need to switch channels to receive or forward packets. Furthermore, LPMC updates the routing path to balance the loads of the channels. LPMC is evaluated by simulation in NS-2, and the results demonstrate that it can effectively increase the channel utilization and network throughput, and decrease the delay.
One-Dimensional Assemblies of Co-doped CdTe Nanoparticles in Aqueous Solution
Shariful I. Mamun,Parthiban Ramasamy,김진권 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.3
One-dimensional (1D) Co-doped CdTe nanorods (NRs) and nanochain assemblies were prepared by spontaneous self-organization of Co-doped CdTe nanoparticles (NPs) in an aqueous solution. The effect of different growth conditions on the formation of 1D assemblies was studied. Formation of nanochains was accelerated by the addition of 50% dimethylsulfoxide to the aqueous growth solution. NRs were obtained by keeping the growth solution at low temperature (4 °C) for 4 days, followed by room-temperature aging for another 4 days. X-ray diffraction patterns of the Co-doped CdTe NPs showed that the same crystal structure as the CdTe nanocrystals was retained, indicating no second phase formation for the Co ions. XPS and ICP-AES data demonstrated successful incorporation of Co ion within CdTe NPs. The room-temperature susceptibility values of Co-doped NPs increased with the doping percentage of Co ions.
A Privacy Preserving Authentication Mechanism for Wireless Mesh Networks
Shariful Islam,Abdul Hamid,Choong Seon Hong 한국정보과학회 2007 한국정보과학회 학술발표논문집 Vol.34 No.2D
Due to its ease of deployment, low cost, self-configuring and self-healing capabilities, Wireless Mesh Networks (WMNs) have emerged as a key technology to be used in a wide scale applications in personal, local, campus, and metropolitan areas. Security and more specifically privacy is an important issue in this type of multi-hop WMN which has given a little attention in the research community. We focus on privacy compromise of a mesh client in a community mesh network that may lead an attacker to reveal mesh clients identity, his other profiles and gain information about mobility. In this paper, we have presented an authentication mechanism with the aid of blind signature that ensures a mesh client to anonymously authenticate itself with a nearby mesh router and thereby preserve identity privacy. We have also presented the security and performance analysis of the proposed scheme.
eMCCA: An Enhanced Mesh Coordinated Channel Access Mechanism for IEEE 802.11s Wireless Mesh Networks
Md. Shariful Islam,무하마드마흐법알람,홍충선,이성원 한국통신학회 2011 Journal of communications and networks Vol.13 No.6
In this paper, we present a channel access mechanism,referred to as the enhanced mesh coordinated channel access (eMCCA)mechanism, for IEEE 802.11s-based wireless mesh networks. The current draft of IEEE 802.11s includes an optional medium access control (MAC), denoted as MCCA, which is designed to provide collision-free and guaranteed channel access during reserved periods. However, the MCCA mechanism fails to achieve the desired goal in the presence of contending non-MCCA nodes; this is because non-MCCA nodes are not aware of MCCA reservations and have equal access opportunities during reserved periods. We first present a probabilistic analysis that reveals the extent to which the performance of MCCA may be affected by contending non-MCCA nodes. We then propose eMCCA, which allows MCCA-enabled nodes to enjoy collision-free and guaranteed channel access during reserved periods by means of prioritized and preemptive access mechanisms. Finally, we evaluate the performance of eMCCA through extensive simulations under different network scenarios. The simulation results indicate that eMCCA outperforms other mechanisms in terms of success rate, network throughput, end-to-end delay, packet-loss rate, and mesh coordinated channel access opportunity-utilization.
Adsorption capability of activated carbon synthesized from coconut shell
Md Shariful Islam,Bee Chin Ang,Samira Gharehkhani,Amalina Binti Muhammad Afifi 한국탄소학회 2016 Carbon Letters Vol.20 No.-
Activated carbon was synthesized from coconut shells. The Brunauer, Emmett and Teller surface area of the synthesized activated carbon was found to be 1640 m2/g with a pore volume of 1.032 cm3/g. The average pore diameter of the activated carbon was found to be 2.52 nm. By applying the size-strain plot method to the X-ray diffraction data, the crystallite size and the crystal strain was determined to be 42.46 nm and 0.000489897, respectively, which indicate a perfect crystallite structure. The field emission scanning electron microscopy image showed the presence of well-developed pores on the surface of the activated carbon. The presence of important functional groups was shown by the Fourier transform infrared spectroscopy spectrum. The adsorption of methyl orange onto the activated carbon reached 100% after 12 min. Kinetic analysis indicated that the adsorption of methyl orange solution by the activated carbon followed a pseudo-second-order kinetic mechanism (R2 > 0.995). Therefore, the results show that the produced activated carbon can be used as a proper adsorbent for dye containing effluents.
eMCCA: An Enhanced Mesh Coordinated Channel Access Mechanism for IEEE 802.11s Wireless Mesh Networks
Islam, Md. Shariful,Alam, Muhammad Mahbub,Hong, Choong-Seon,Lee, Sung-Won The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.6
In this paper, we present a channel access mechanism, referred to as the enhanced mesh coordinated channel access (eMCCA) mechanism, for IEEE 802.11s-based wireless mesh networks. The current draft of IEEE 802.11s includes an optional medium access control (MAC), denoted as MCCA, which is designed to provide collision-free and guaranteed channel access during reserved periods. However, the MCCA mechanism fails to achieve the desired goal in the presence of contending non-MCCA nodes; this is because non-MCCA nodes are not aware of MCCA reservations and have equal access opportunities during reserved periods. We first present a probabilistic analysis that reveals the extent to which the performance of MCCA may be affected by contending non-MCCA nodes. We then propose eMCCA, which allows MCCA-enabled nodes to enjoy collision-free and guaranteed channel access during reserved periods by means of prioritized and preemptive access mechanisms. Finally, we evaluate the performance of eMCCA through extensive simulations under different network scenarios. The simulation results indicate that eMCCA outperforms other mechanisms in terms of success rate, network throughput, end-to-end delay, packet-loss rate, and mesh coordinated channel access opportunity-utilization.