Papers by Md Shariful Islam
Asian Journal of Empirical Research
The study examines the impact of information and communications technology (ICT) on bilateral exp... more The study examines the impact of information and communications technology (ICT) on bilateral export flows from Bangladesh to its trading partners based on an augmented panel gravity model. It includes 108 importers of Bangladeshi goods. The sample period extends from 2000 to 2018. Primarily, we employ Pooled Ordinary Least Square (POLS) model, and we utilize Poisson Pseudo Maximum Likelihood (PPML) as an alternative estimation technique to check robustness. The findings from the OLS model indicate that ICT has positive and significant effects on Bangladesh’s bilateral export. The results from PPML also support the findings from the OLS model. Therefore, the results come out to be robust. These findings imply that by reducing trade-related costs e. g., shipping costs, market access costs, and communication and information costs, ICT growth in Bangladesh as well as in its trading partner countries enhances trade flows and therefore has a trade-boosting effect.
Processes
Using biodiesel in diesel engines is beneficial for reducing emissions of carbon monoxide (CO), h... more Using biodiesel in diesel engines is beneficial for reducing emissions of carbon monoxide (CO), hydrocarbons (HC) and particulate matters (PM). Biodiesel is usually produced from vegetable oils or animal fats. When produced from plant oil or woody plant sources, biodiesel can reduce a significant amount of carbon dioxide on a life cycle basis. The objective of this study is to produce biodiesel from a non-conventional woody plant source that is, crude tall oil, which is a dark brown viscous liquid extracted and processed in wood pulping plants. It contains a high percentage of fatty acids. From raw crude tall oil, tall oil fatty acids were separated and were successfully used for the production of biodiesel in this study. Although biodiesel produces lower CO, HC and PM than petroleum diesel fuel, it produces higher oxides of nitrogen (NOx) emissions in diesel engines. Water emulsifications of diesel-biodiesel blends are investigated in a direct injection (DI) diesel engine in this w...
Clinical Epidemiology and Global Health, 2021
Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.
Bangladesh has been combating the COVID-19 pandemic with limited financial resources and poor hea... more Bangladesh has been combating the COVID-19 pandemic with limited financial resources and poor health infrastructure since March, 2020. Although the government has imposed several restricted measures to curb the progression of the outbreak, these arrays of measures are not sustainable in the long run. In this study, we assess the impact of lift of flexible lockdown on the COVID-19 dynamics in Bangladesh. Our analysis demonstrates that the country might experience second infection peak in 6-7 months after the withdrawal of current lockdown. Moreover, a prolonged restrictions until January, 2021 will shift the infection peak towards August, 2021 and will reduce approximately 20 % COVID-19 cases in Bangladesh.What we knowBangladesh has been going through COVID-19 crisis and in response, the Government has implemented restricted array of measures to curb the COVID-19 outbreak in Bangladesh.What this article addsThe impact of ‘no lockdown’ policies on COVID-19 pandemic in Bangladesh.Appea...
Separations, 2020
Crude tall oil (CTO) is the third largest by-product at kraft pulp and paper mills. Due the large... more Crude tall oil (CTO) is the third largest by-product at kraft pulp and paper mills. Due the large presence of value-added fatty and resin acids, CTO has a huge valorization potential as a biobased, readily available, non-food, and low-cost biorefinery feedstock. The objective of this work was to present a method for the isolation of high-value linoleic acid (LA), an omega (ω)-6 essential fatty acid, from CTO using a combination of pretreatment, fractionation, and purification techniques. Following the distillation of CTO to separate the tall oil fatty acids (TOFAs) from CTO, LA was isolated and purified from TOFAs by urea complexation (UC) and low-temperature crystallization (LTC) in the temperature range between −7 and −15 °C. The crystallization yield of LA from CTO in that range was 7.8 w/w at 95.2% purity, with 3.8% w/w of ω-6 γ-linolenic acid (GLA) and 1.0% w/w of ω-3 α-linolenic (ALA) present as contaminants. This is the first report on the isolation of LA from CTO. The approa...
Lecture Notes in Computer Science, 2009
The current draft standard of 802.11s has defined routing for Wireless Mesh Networks (WMNs) in la... more The current draft standard of 802.11s has defined routing for Wireless Mesh Networks (WMNs) in layer-2 and to differentiate from layer-3 routing, it termed layer-2 routing as path selection. The layer-2 path selection (LPS) mechanism is fully specified in the draft of IEEE 802.11s for WMNs. However, routing with security provision is not specified in the standard. Our study identifies that the current path selection mechanism is vulnerable to various types of routing attacks like flooding, route redirection , spoofing etc. In this paper, we develop a novel Secure Layer-2 Path Selection (SLPS) mechanism that uses cryptographic extensions to provide authenticity and integrity of routing messages. Particularly, the proposed SLPS prevents unauthorized manipulation of mutable fields in the routing messages. Results from analysis and simulation demonstrate that SLPS protocol is robust against identified attacks and provides higher packet delivery ratio, requires no extra communication cost and incurs little path acquisition delay, computational and storage overhead to accomplish secure path selection.
Lecture Notes in Computer Science, 2009
In recent years, mesh networking has emerged as a key technology for the last mile Internet acces... more In recent years, mesh networking has emerged as a key technology for the last mile Internet access and found to be an important area of research and deployment. The current draft standard of IEEE 802.11s has defined routing for Wireless Mesh Networks (WMNs) in layer-2 and is termed as Hybrid Wireless Mesh Protocol (HWMP). However, security in routing or forwarding functionality is not specified in the standard. As a consequence, HWMP in its current from is vulnerable to various types of routing attacks such as flooding, route disruption and diversion, spoofing etc. In this paper, we propose SHWMP, a secure HWMP protocol for WMN. The proposed protocol uses cryptographic extensions to provide authenticity and integrity of HWMP routing messages and prevents unauthorized manipulation of mutable fields in the routing information elements. We show via analysis that the proposed SHWMP successfully thwarts all the identified attacks. Through extensive ns-2 simulations, we show that SHWMP provides higher packet delivery ratio with little increase in end-to-end delay, path acquisition delay and control byte overhead.
2010 IEEE Wireless Communication and Networking Conference, 2010
Abstract This paper presents an enhanced channel access mechanism for the newly introduced Mesh D... more Abstract This paper presents an enhanced channel access mechanism for the newly introduced Mesh Deterministic Access (MDA) mechanism for IEEE 802.11 s based Wireless Mesh Networks (WMNs). The MDA is an optional scheduled access mechanism which ...
2010 8th Annual Communication Networks and Services Research Conference, 2010
The well known many-to-one data routing paradigm [1] in wireless sensor networks (WSNs) demands n... more The well known many-to-one data routing paradigm [1] in wireless sensor networks (WSNs) demands nonuniform medium access and forwarding strategy to achieve the ultimate node level fairness. Since nodes closer to the sink have more traffic than that of faraway nodes, close-by nodes need to employ different frequency of media access and forwarding probability such that sink receives almost equal number of packets from all the nodes in the network. In this paper, we design a distributed fair data collection protocol where the nodes can decide their media access and packet forwarding strategies within the WSN such that a fair throughput can be enjoyed by each node irrespective of the node's distance from the sink. We demonstrate the effectiveness of our solution through simulations and results show that the proposed protocol ensures the fair delivery of packets, improves throughput and reduces end-toend delay for the different WSN scenarios under study.
Proceedings of the 4th International Conference on Uniquitous Information Management and Communication, 2010
The IEEE 802.11s draft is the first attempt to develop a standard fully intended for the rapidly ... more The IEEE 802.11s draft is the first attempt to develop a standard fully intended for the rapidly growing Wireless Mesh Networks (WMNs). Performance of a WMN is largely affected by the design of routing protocol and the associated metric. The recent version D2.02 of 802.11s has defined Hybrid Wireless Mesh Protocol (HWMP) and Airtime as the default path selection protocol and metric, respectively. However, Airtime and other well known existing routing metrics do not consider the impact of backoff delay and queueing delay, and hence, ignored some important factors like transmission time of the contending nodes, their loads and densities which might hinder the network performance. In this paper, we first identify the parameters that affect the forwarding time of a packet and then, design a new routing metric referred to as EFD (Expected Forwarding Delay) that estimates the forwarding time of a packet of particular traffic class in a node and selects the best path (high throughput) having minimum cumulative expected forwarding delay. We also made changes to the path selection criteria, metric propagation and route update intervals of HWMP, so that more stable paths can be chosen. Finally, we incorporate our new metric with the modified HWMP and study the performance through extensive simulations. Results indicate that the proposed mechanism outperforms others in terms of average network throughput, end-to-end delay and packet loss rate.
2008 IEEE Wireless Communications and Networking Conference, 2008
Our study on the deployment topology and communication characteristics of wireless mesh enterpris... more Our study on the deployment topology and communication characteristics of wireless mesh enterprise networks (WMENs) leads to three critical security challenges: (a) deployment of network devices are not planar, rather devices are deployed over three-dimensional space, (b) message generated/received by a mesh client traverses through mesh routers in a multi-hop fashion, and (c) mesh clients being mostly mobile in nature may result in misbehaving or spurious during communications. We address these challenges for WMENs that may be a small network within an office or a medium-size network for all offices in an entire building, or a large scale network among offices in multiple buildings. We develop a matrix key distribution technique that perfectly suits the network topology. A session key establishment protocol is presented to achieve the client-router and router-router communication security. Finally, a misbehaving client detection algorithm is developed based on the communication history. We analyze and evaluate the performance to show the suitability of our proposed security solutions.
2008 10th International Conference on Advanced Communication Technology, 2008
In this paper we propose a detection technique to identify misbehaving client in wireless mesh ne... more In this paper we propose a detection technique to identify misbehaving client in wireless mesh networks. The technique is devised based on the communication history for two communicating clients through a common set of routers. Individual trust relationship is calculated for both the clients with their common routers. Then a correlation value for each client is found and compared with a predefined threshold to determine whether a client is spurious or not. We evaluate the performance of the proposed detection technique through simulation and results show that the detection efficiency is better with small number of misbehaving clients.
Sensors, 2010
In recent years, a significant number of sensor node prototypes have been designed that provide c... more In recent years, a significant number of sensor node prototypes have been designed that provide communications in multiple channels. This multi-channel feature can be effectively exploited to increase the overall capacity and performance of wireless sensor networks (WSNs). In this paper, we present a multi-channel communications system for WSNs that is referred to as load-adaptive practical multi-channel communications (LPMC). LPMC estimates the active load of a channel at the sink since it has a more comprehensive view of the network behavior, and dynamically adds or removes channels based on the estimated load. LPMC updates the routing path to balance the loads of the channels. The nodes in a path use the same channel; therefore, they do not need to switch channels to receive or forward packets. LPMC has been evaluated through extensive simulations, and the results demonstrate that it can effectively increase the delivery ratio, network throughput, and channel utilization, and that it can decrease the end-to-end delay and energy consumption.
Journal of Communications and Networks, 2011
In this paper, we present a channel access mechanism, referred to as the enhanced mesh coordinate... more In this paper, we present a channel access mechanism, referred to as the enhanced mesh coordinated channel access (eM-CCA) 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 eM-CCA outperforms other mechanisms in terms of success rate, network throughput, end-to-end delay, packet-loss rate, and mesh coordinated channel access opportunity-utilization.
European Journal of Neuroscience, 2000
Schwann cells participate in myelin phagocytosis in the early stage of Wallerian degeneration, pr... more Schwann cells participate in myelin phagocytosis in the early stage of Wallerian degeneration, prior to the recruitment of macrophages. This is the ®rst report that Schwann cells induce heme oxygenase-1 (HO-1), a 32-kDa heat shock protein, only when they have transformed into myelin-phagocytosing cells from myelinating cells (days 2±3) immediately after crush injury of rat sciatic nerves. Double immuno¯uorescent labelling for HO-1 and transferrin receptors revealed that HO-1-immunoreactive Schwann cells also expressed transferrin receptors suggesting activation of iron metabolism. The transient induction of HO-1 in Schwann cells may contribute to the adaptive function in an altered environment when the cells have lost contact with axons, and may play a crucial role in the ensuing regeneration.
annals of telecommunications - annales des télécommunications, 2010
In general, wireless sensor networks (WSNs) consist of many sensors which transmit data to a cent... more In general, wireless sensor networks (WSNs) consist of many sensors which transmit data to a central node, called the sink, possibly over multiple hops. This many-to-one data routing paradigm leads to nonuniform traffic distribution for the different sensors (e.g., nodes closer to the sink transfer more traffic than those farther away). In this paper, we perform an analysis of the fairness issue by presenting a tree-based WSN and derive the throughput, delay, and energy distribution for each sensor under the fairness constraint. Based on the analysis, we design our fair data collection protocol in which each node decides its media access and packet forwarding strategies in a distributed manner. Finally, we demonstrate the effectiveness of our solution through simulations. The results for the proposed protocol show the accuracy of the analysis and show
annals of telecommunications - annales des télécommunications, 2010
This paper presents a fair and efficient rate control mechanism, referred to as congestion-aware ... more This paper presents a fair and efficient rate control mechanism, referred to as congestion-aware fair rate control (CFRC), for IEEE 802.11s-based wireless mesh networks. Existing mechanisms usually concentrate on achieving fairness and achieve a poor throughput. This mainly happens due to the synchronous rate reduction of neighboring links or nodes of a congested node without considering whether they actually share the same bottleneck or not. Furthermore, the achievable throughput depends on the network load, and an efficient fair rate is achievable when the network load is balanced. Therefore, existing mechanisms usually achieve a fair rate determined by the mostly loaded network region. CFRC uses an AIMD-based rate control mechanism which enforces a rate-bound to the links that use the same bottleneck. To achieve the maximum
annals of telecommunications - annales des télécommunications, 2009
In this paper, we present a throughputmaximizing routing metric, referred to as expected forwardi... more In this paper, we present a throughputmaximizing routing metric, referred to as expected forwarding time (EFT), for IEEE 802.11s-based wireless mesh networks. Our study reveals that most of the existing routing metrics select the paths with minimum aggregate transmission time of a packet. However, we show by analyses that, due to the shared nature of the wireless medium, other factors, such as transmission time of the contending nodes and their densities and loads, also affect the performance of routing metrics. We therefore first identify the factors that hinder the forwarding time of a packet. Furthermore, we add a new dimension to our metric by introducing traffic priority into our routing metric design, which, to the best of our knowledge, is completely unaddressed by existing studies. We also show how EFT can be incorporated into the hybrid wireless mesh protocol (HWMP), the
Acta Histochemica et Cytochemica, 1997
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Papers by Md Shariful Islam