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Estimation of Packet Loss on MAC Layer in IEEE 802.11 Wireless Local Area Networks
Shafi Shahsavar Mirza,Khaled M. Almustafa 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.2
In wireless local area networks, management decisions concerning channel selection, rate selection, and power management have a profound impact on the throughput performance, particularly in dense areas. These measurements, however, are too weakly associated with the MAC layer to be able to make such management decisions. Therefore, direct measurements of the channel quality at the MAC layer are necessary to facilitate appropriate decision-making activities. Estimating quantities, such as the probability of collision and the probability of channel-induced errors, will enable the MAC layer to make suitable decisions1. This paper proposes a mechanism to calculate both the channel error probability and collision probability through the methodology of distribution. Some scenarios are discussed to demonstrate the effectiveness of the measurements.
( Shafi Noor Islam ) 한국정책학회 2015 International Journal of Policy Studies Vol.6 No.1
The char-lands are highly vulnerable to natural disasters in the Ganges-Padma River basin. Over 12 million char dwellers are affected by annual floods, erosion and struggling against livelihoods sustainability and stability of settlements location. The newly emerged land in the river channel is called char-land or diara. Purba Khas Bandarkhola Mouza (Seat 3) of Char-Janajat is a unique char which is located in the Ganges-Padma River channel where over 3000 people are affected. The settlements and people of the char-lands are under threat due to floods which have exerted a greater impact on culture, society and local economy. The six livelihood assets (human capital, natural capital, financial capital, physical capital, political capital and social capital) have been considered in char-land development approach, but this study found that culture, heritage and cultural identity could be included with the other six assets of char-lands livelihoods sustainability. The study found that the important issues such as socio-economy, livelihoods and their resilient to the impacts of flood and erosion hazards. This is necessary to control or adapt the vulnerabilities through developmental strategic policies implementation. The objective of this study is to develop an integrated framework and policies for settlement and livelihoods sustainability in the Ganges-Padma River basin in Bangladesh.
Bridging the Connectivity Gap within a PLC and Wi-Fi Hybrid Network
Shafi Ullah Khan,황태웅,구인수 국제문화기술진흥원 2023 International Journal of Advanced Culture Technolo Vol.11 No.1
The implementation of a hybrid network utilizing Power Line Communication (PLC) and Wi-Fi technologies has been demonstrated to improve signal strength and coverage in areas with poor connectivity due to internet shadow areas. In this study we strategically positioned Wi-Fi relays and utilized the capabilities of PLC technology to significantly improve signal strength and coverage in areas with poor connectivity. We also analyzed the effects of metallic obstacles on Wi-Fi signal propagation and proposed a solution to strengthen the signal enough to pass through them. Our experiment demonstrated the feasibility and potential of using this hybrid network in industrial scenarios for real-time data transmission. Overall, the results suggest that the use of PLC and Wi-Fi hybrid networks can be a cost-effective and efficient solution for overcoming internet connectivity challenges and has the potential to provide high-speed internet access to areas with unreliable signals.
Impact and Delamination Failure of Multiscale Carbon Nanotube-Fiber Reinforced Polymer Composites
Shafi Ullah KHAN,Jang-Kyo Kim 한국항공우주학회 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2
Fiber reinforced polymer composites (FRPs) are being increasingly used for a wide range of engineering applications owing to their high specific strength and stiffness. However, their through-the-thickness performance lacks some of the most demanding physical and mechanical property requirements for structural applications, such as aerospace vehicles and military components. Carbon nanotubes (CNTs) and carbon nanofibers (CNFs), due to their excellent mechanical, thermal and electrical properties, offer great promise to improve the weak properties in the thickness direction and impart multi-functionality without substantial weight addition to FRPs. This paper reviews the progress made to date on i) the techniques developed for integration of CNTs/CNFs into FRPs, and ii) the effects of the addition of these nanofillers on the interlaminar properties, such as such interlaminar shear strength, interlaminar fracture toughness and impact damage resistance and tolerance, of FRPs. The key challenges and future prospects in the development of multiscale CNT-FRP composites for advanced applications are also highlighted.
( Shafi Noor Islam ),( Nabi Noor Islam ),( Amirul Islam Sada ) 한국정책학회 2019 International Journal of Policy Studies Vol.10 No.1
The rural area of Bangladesh is gifted with vast natural resources, deltaic flat and rural ecological environment which is impending for communities’ survival. Rural landuse changes which have been extended a greater impact on culture, society and local economy. Over 65 % villagers are directly dependent on rural resources. The countryside natural resources are enormously important for socio-economic enhancement. Kalabadha is one of the villages of Jamalpur district in Bangladesh whose landuse pattern is continuously altering. The rural villages are tremendously changed due to rural development policy applications. Within this policy the rural urban migration, push pull factors, rural women micro entrepreneurship development and diversification of rural economic activities are remodeling the village character. As a result Kalabadha village is losing its geomorphological characters, but the socio- economic enhancement is getting speedily. The dwellers have improved their socio-economic status through application of livelihood framework with seven livelihood assets. The study seeks the rural landuse, landscape protection within a planning policy approach to ensure livelihoods sustainability as well as rural development of Kalabadha village of Jamalpur district besides other villages in Bangladesh.
Mohammed Shafi Ullah Bhuiyan,임용표,민성란,최관삼,유장렬 한국식물생명공학회 2009 식물생명공학회지 Vol.36 No.1
An efficient and reproducible plant regeneration system was established using transverse thin cell layers (tTCLs) in five cultivars of Brassica juncea L. The effects of medium conditions, explant types (tTCLs of hypcotyl and cotyledonary petiole) on shoot regeneration were examined in this study. The maximum shoot regeneration frequency was obtained in Murashige and Skoog (MS) medium supplemented with 4 mg/L 6-benzylaminopurine (BA) and 0.2 mg/L 1-naphthaleneacetic acid (NAA). The hypocotyls derived tTCL explants had more shoot regeneration frequency (52%) than the cotyledonary petiole derived tTCL explants. Shoot induction was further improved by the addition of silver nitrate (AgNO3) in the regeneration medium. A significant genotypic effect was also observed between the five cultivars; Rai-5 displayed higher capacities to produce shoots than other cultivars. Regenerated shoots were rooted on MS basal medium without PGRs which induced 90% of roots. The plantlets established in greenhouse conditions with 99% survival, flowered normally and set seeds. The regenerated plants were fertile and identical to source plants.
Mohammed Shafi Ullah Bhuiyan,민성란,최관삼,임용표,유장렬 한국식물생명공학회 2009 식물생명공학회지 Vol.36 No.2
An efficient system for high frequency plant regeneration was established through investigating various factors such as plant growth regulator combinations, explant types and ages, and addition of AgNO3 influenced on shoot regeneration in Brassica juncea L. cv. BARI sarisha-10. Murashige and Skoog (MS) medium supplemented with 0.1 mg/L NAA (1-naphthaleneacetic acid) and 1 mg/L BA (6-benzyladenine) showed the maximum shoot regeneration frequency (56.67%) among the different combinations of NAA and BA. Explant type, explant age, and addition of AgNO3 also significantly affected shoot regeneration. Of the four type of explants (cotyledon, hypocotyl, root, and leaf explants)- cotyledon explants produced the highest shoot regeneration frequency and hypocotyls explants produced the highest number of shoots per explant, whereas root explants did not produce any shoot. The cotyledonary explants from Four-day-old seedlings showed the maximum shoot regeneration frequency and number of shoots per explant. Shoot regeneration frequency increased significantly by adding AgNO3 to the medium. Two mg/L AgNO3 appeared to be the best for shoot regeneration with the highest shoot regeneration frequency (86.67%) and number of shoots per explant (7.5 shoots). Considerable variation in shoot regeneration from cotyledonay explants was observed within the B. juncea L. genotypes. The shoot regeneration frequency ranged from 47.78% for cv. Shambol to 91.11% for cv. Rai-5. In terms of the number of shoots produced per explant, B. juncea L. cv. Daulot showed the maximum efficiency. MS medium supplemented with 0.1 mg/L NAA showed the highest frequency of rooting. The regenerated plantlets were transferred to pot soil and grown to maturity in the greenhouse. All plants were fertile and morphologically identical with the source plants.