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Masum, Kazi Mohammad,Mamun, Abdullah Al,Mamun-Or-Rashid, Mohammad,Abdullah-Al-Mamun, M. M.,Islam, Mohammad Nabidul Institute of Forest Science 2012 Journal of Forest Science Vol.28 No.2
An explanatory survey was conducted to assess preference and consumption pattern of horticultural species, their sources, location-wise planting preferences and diversity of these species in the rural homestead forest of the offshore island of Bangladesh. Assessment was done through multistage random sampling. Based on homestead size respondents were categorized into small (<0.05 ha), medium (0.05-0.25 ha) and large (>0.25 ha) and twenty from each category were selected randomly for the study. The study revealed that most of the farmer (75.5%) preferred to plant fruit tree species for future plantation followed by timber species (62.2%). But fruit-bearing plants were being gradually replaced by some exotic timber species such as Swietenia mahagoni, Acacia auriculiformis, Tectona grandis, Eucalyptus spp., etc. Diversity and abundance of fruit species was found higher in almost all homestead. A total of 41 horticultural species were identified and seven horticultural species among them were recognized as the most preferred ones in the study area. Consumption pattern was chiefly to meet the nutritional demand and to gain a quick monetary benefit. Average annual income from horticultural species was 7,183.33 Taka (US$102).
Kazi Mohammad Masum,Abdullah Al Mamun,Mohammad Mamun-Or-Rashid,M. M. Abdullah-Al-Mamun,Mohammad Nabidul Islam 강원대학교 산림과학연구소 2012 Journal of Forest Science Vol.28 No.2
An explanatory survey was conducted to assess preference and consumption pattern of horticultural species, their sources,location-wise planting preferences and diversity of these speci es in the rural homestead forest of the offshore island of Bangladesh. Assessment was done through multistage random sampling. Based on homestead size respondents were categorized into small (<0.05 ha), medium (0.05-0.25 ha) and large (>0.25 ha) and twenty from each category were selected randomly for the study. The study revealed that most of the farmer (75.5%) preferred to plant fruit tree species for future plantation followed by timber species (62.2%). But fruit-bearing plants were being gradually replaced by some exotic timber species such as Swietenia mahagoni, Acacia auriculiformis, Tectona grandis, Eucalyptus spp., etc. Diversity and abundance of fruit species was found higher in almost all homestead. A total of 41 horticultural species were identified and seven horticultural species among them were recognized as the most preferred ones in the study area. Consumption pattern was chiefly to meet the nutritional demand and to gain a quick monetary benefit. Average annual income from horticultural species was 7,183.33 Taka (US$102).
Preventing Tunneling Attack Using Minimum and Approximate Hop Count for Secure MANET Routing
( Mamun-or-rashid ),( Choong Seon Hong ) 한국정보처리학회 2004 한국정보처리학회 학술대회논문집 Vol.11 No.2
Providing security in any network is a well-studied problem. It is particularly arduous and challenging in mobile ad hoc networking. A number of attacks have been identified in mobile ad hoc network (MANET) routing. One such severe attack is tunneling attack that is difficult to protect against. Among the attacks tunneling attack, where two or more nodes may collaborate to encapsulate and exchange messages between them along with the existing data routes. One vulnerability is that two such nodes may collaborate to falsely represent the length of the available paths by encapsulating and tunneling between them legitimate route messages generated by other nodes. In this paper we propose minimum and approximation hop count for preventing tunneling attack. Distance between source and destination is calculated using GPS based location information and based on transmission range of the nodes we can calculate minimum and approximate hop between two nodes. Comparing the hop count from the packet received at the node with the minimum or approximate hop count we can discard falsifying routes and neighbors generated by the malicious nodes. Our proposal hinders from false routes and fake neighbors with little data overhead of added location information and processing overhead at the source and destination.
( Mamun-or-rashid ),( Choong Seon Hong ) 한국정보처리학회 2007 한국정보처리학회 학술대회논문집 Vol.14 No.1
Congestion in WSN increases energy dissipation rates of sensor nodes as well as loss of packets and thereby hinders fair and reliable event detections. We find that one of the key reasons of congestion in WSN is allowing sensing nodes to transfer as many packets as possible. This is due to the use of CSMA/CA that gives opportunistic media access control. In this paper, we propose an energy efficient congestion avoidance protocol that includes source count based hierarchical and load adaptive medium access control. Our proposed mechanism ensures load adaptive media access to the nodes and thus achieves fairness in event detection. The results of simulation show our scheme exhibits more than 90% delivery ratio with retry limit 1, even under bursty traffic condition which is good enough for reliable event perception.
Effect of hot-casted NiO hole transport layer on the performance of perovskite solar cells
Mamun, Abdullah Al,Ava, Tanzila Tasnim,Abdel-Fattah, Tarek M.,Jeong, Hyeon Jun,Jeong, Mun Seok,Han, Seonhye,Yoon, Hargsoon,Namkoong, Gon Elsevier Science B.V., Amsterdam. 2019 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.188 No.-
<P><B>Abstract</B></P> <P>NiO is extensively studied as a hole transport layer in perovskite solar cells but syntheses of NiO precursor involves toxic chemicals and time-consuming processes. Moreover, the synthesized NiO contains surface defects acting as trapping sites at the NiO/perovskite interfaces, resulting in poor charge extraction, hysteresis and light soaking. In this manuscript, we developed a non-toxic methodology for NiO precursor solution by using a simple mixture of NiO powder and HCl in an air environment. In addition, a new hot-casting technique was developed to successfully fabricate densely-packed, less defective NiO films. Interestingly, the hot-casting temperature was found to significantly affect morphology, film coverage and surface defects of NiO films. When a hot-casting temperature was below 100 °C, non-uniform NiO films were sparsely formed on the FTO surface and were characterized by defects in the form of hydroxyl groups and water on the surface. Such defective NiO films resulted in severe hysteresis and light soaking effect due to the trapped charges at the defective NiO/perovskite interface of perovskite solar cells. In contrast, when the hot-casting temperature was 120 °C, the NiO film formed densely-packed morphologies, covering the FTO surface. Furthermore, this film exhibited an ordered chemistry with strong Ni-O octahedral bonding and facilitated charge extraction at NiO/perovskite interface, resulting in a negligible hysteresis and light soaking. Finally, this non-toxic and simple method of fabricating NiO film will assist further development of perovskite solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A quick, simple, inexpensive, and non-toxic methodology was developed for preparing NiO precursor solution. </LI> <LI> A new hot-casting technique was developed to fabricate densely-packed, less defective NiO films. </LI> <LI> Hot-casted NiO resulted in a negligible hysteresis and light soaking of perovskite solar cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Mamun, Abdulla Hel Al,Son, Seung-Bae,Hahn, Jae-Ryang Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.1
We investigated the effects of tunneling current on scanning tunneling microscopy (STM) images of 1-octanethiol (OT) and 1-decanethiol (DT) self-assembled monolayers (SAMs). At a low tunneling current, the domain boundaries and ordered alkanethiol molecules were clearly resolved. As the tunneling current was increased at a constant bias voltage, however, the STM images showed disordered structures of the OT and DT SAMs. As the tunneling current was reduced back to low values, the ordered structures of the alkanethiol molecules reappeared. The reversibility of the process suggests that the sulfur head groups did not rearrange under any of the tunneling current conditions. On the basis of our observations, which are inconsistent with the standard model for STM imaging of molecules on metal surfaces, we consider the STM imaging mechanism in terms of a two-region tunneling junction model.
Mamun Abdullah Al,Rahman Muhammed Forruq,Aysha Akhtar,Md. Wahidul Alam,Mohammad Nurul Azim Sikder,Alan Warren,Henglong Xu 한국해양과학기술원 2018 Ocean science journal Vol.53 No.4
To investigate the seasonal heterogeneity of the periphytic ciliate communities, a 1-year baseline survey was conducted in the Karnaphuli River estuary, northern Bay of Bengal, Bangladesh. A total of 54 ciliate species were recorded, including seven common and 14 dominant species. Maximum species number was in autumn whereas maximum abundance was in winter; the minimum for both occurred in summer. Multivariate analyses, i.e., canonical analysis of principal coordinates (CAP) and principal co-ordinates analysis (PCoA), revealed a clear seasonal heterogeneity of community structure and environmental variables. Multivariate correlation analysis (RELATE) demonstrated that the community structure of the periphytic ciliate communities was significantly correlated with environmental variables, and best matching analysis (BIOENV) indicated that heterogeneity of community patterns was mainly driven by water temperature, pH, dissolved oxygen, total dissolved solids and nutrients. Species richness and diversity peaked in autumn whereas species evenness peaked in summer. These results suggest that environmental conditions shape periphytic ciliate community structure, which is a potentially useful bio-indicator of estuarine water quality.