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Energy-Efficient Cooperative Medium Access Control (MAC) Protocol for Wireless Sensor Networks
Mohammad Helal Uddin Ahmed,Choong Seon Hong 한국정보과학회 2011 한국정보과학회 학술발표논문집 Vol.38 No.1D
Recent research activities in cooperative communication focus on achieving energy efficiency and reliability. Relay selection strategy for cooperative communication improves the performance significantly. However, due to imbalance consumption of power, network might die earlier and more than 90% energy remains unused. In this paper, we provide a framework of an energy-efficient medium access control protocol that minimizes these problems and improves energy efficiency.
Improvement in DRX Power Saving for Non-real-time Traffic in LTE
Mohammad Tawhid Kawser,Mohammad Rakibul Islam,Khondoker Ziaul Islam,Mohammad Atiqul Islam,Mohammad Mehadi Hassan,Zobayer Ahmed,Rafid Hasan 한국전자통신연구원 2016 ETRI Journal Vol.38 No.4
A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-real-time traffic does not essentially impact the user’s experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement.
Effective Diagnosis and Monitoring of Heart Disease
Ahmed Fawzi Otoom,Emad E. Abdallah,Yousef Kilani,Ahmed Kefaye,Mohammad Ashour 보안공학연구지원센터 2015 International Journal of Software Engineering and Vol.9 No.1
Wearable sensor mobile technologies and machine learning techniques are considered as two of the key research areas in the computer science and healthcare application industries. Our main aim is to build a simple yet accurate mobile application that is capable of real-time diagnosis and monitoring of patients with Coronary Artery Disease (CAD) or heart disease which is a major cause of death worldwide. Most available mobile healthcare systems focus on the data acquisition and monitoring component with little attention paid to real-time diagnosis. In this work, we build an intelligent classifier that is capable of predicting a heart disease problem based on clinical data entered by the user or the doctor and by using machine learning algorithms. This diagnosis component is integrated in the mobile application with a real-time monitoring component that continuously monitors the patient and raises an alarm whenever an emergency occurs. Our results show that the proposed diagnosis component has proved successful with a classification performance accuracy of more than 85% with the cross-validation test. Moreover, the monitoring algorithm provided a 100% detection rate.
Outdoor Applications of Hyperspectral Imaging Technology for Monitoring Agricultural Crops: A Review
Ahmed, Mohammad Raju,Yasmin, Jannat,Mo, Changyeun,Lee, Hoonsoo,Kim, Moon S.,Hong, Soon-Jung,Cho, Byoung-Kwan Korean Society for Agricultural Machinery 2016 바이오시스템공학 Vol.41 No.4
Background: Although hyperspectral imaging was originally introduced for military, remote sensing, and astrophysics applications, the use of analytical hyperspectral imaging techniques has been expanded to include monitoring of agricultural crops and commodities due to the broad range and highly specific and sensitive spectral information that can be acquired. Combining hyperspectral imaging with remote sensing expands the range of targets that can be analyzed. Results: Hyperspectral imaging technology can rapidly provide data suitable for monitoring a wide range of plant conditions such as plant stress, nitrogen status, infections, maturity index, and weed discrimination very rapidly, and its use in remote sensing allows for fast spatial coverage. Conclusions: This paper reviews current research on and potential applications of hyperspectral imaging and remote sensing for outdoor field monitoring of agricultural crops. The instrumentation and the fundamental concepts and approaches of hyperspectral imaging and remote sensing for agriculture are presented, along with more recent developments in agricultural monitoring applications. Also discussed are the challenges and limitations of outdoor applications of hyperspectral imaging technology such as illumination conditions and variations due to leaf and plant orientation.
Ahmed, Mohammad Shamsuddin,Kim, Young-Bae Elsevier 2017 Carbon Vol.111 No.-
<P>A porous graphene catalyst was prepared with 1,4-diaminobutane (DAB) through amide functionalization and was used as a metal-free electrocatalyst for oxygen reduction reaction (ORR) in alkaline fuel cells. DAB was used as a junction among functionalized graphene layers to impart electrocatalytic activity for the ORR resultant from the interlayer charge transfer. The successful amidation and subsequent reduction in the process of catalyst preparation were confirmed using X-ray photoelectron spectroscopy. A hierarchical porous structure was also confirmed through the surface morphological analysis. The Brunauer-Emmett-Teller specific surface area and thermal stability increased by 2.6- and 1.5-fold, respectively, after successful amide functionalization. The as-prepared catalyst was proved an efficient metal-free electrocatalyst with better electrocatalytic activity, stability, and tolerance to the crossover effect than commercially available Pt/C for ORR by a direct four-electron involved pathway. These results indicate that the amide-functionalized graphene metal-free catalyst reported in this study is a promising alternative to traditional noble metal-based ORR catalysts. (C) 2016 Elsevier Ltd. All rights reserved.</P>
Mohammad Gholami,Mojtaba Gorji Azandariani,Ahmed Najat Ahmed,Hamid Abdolmaleki Techno-Press 2023 Advances in nano research Vol.14 No.2
This paper studies the free vibration behavior of bi-dimensional functionally graded (BFG) nanobeams subjected to arbitrary boundary conditions. According to Eringen's nonlocal theory and Hamilton's principle, the underlying equations of motion have been obtained for BFG nanobeams. Moreover, the variable substitution method is utilized to establish the structure's state-space differential equations, followed by forming the dynamic stiffness matrix based on state-space differential equations. In order to compute the natural frequencies, the current study utilizes the Wittrick-Williams algorithm as a solution technique. Moreover, the nonlinear vibration frequencies calculated by employing the proposed method are compared to the frequencies obtained in previous studies to evaluate the proposed method's performance. Some illustrative numerical examples are also given in order to study the impacts of the nonlocal parameters, material property gradient indices, nanobeam length, and boundary conditions on the BFG nanobeam's frequency. It is found that reducing the nonlocal parameter will usually result in increased vibration frequencies.
Mohammad Asadullah,Mohammad Shajahan Kabir,Mohammad Boshir Ahmed,Nadiah Abdul Razak,Nurul Suhada Abdur Rasid,Airin Aezzira 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.12
Activated carbons have been prepared from jute stick by both chemical and physical activation methods using zinc chloride and steam, respectively. They were characterized by evaluating surface area, iodine number, pore size distribution, and concentration of surface functional groups. The chemically activated carbon largely featured micropore structure,while the physically activated carbon mainly featured macropore structure. The specific surface area of chemically and physically activated carbons was 2,325 and 723 m2/g, while the iodine number was 2,105 and 815mg/g, respectively. The concentration of surface functional groups was determined by Boehm titration method, which suggested that different types of surface functional groups are randomly distributed on chemical activated carbons, while it is limited for physical activated carbon. The microporosity along with surface functional groups provided a unique property to chemically activated carbon to adsorb Methylene Blue dye to a large extent. The adsorption of dye was also affected by the adsorption parameters such as adsorption time, temperature and pH. Comparatively, higher temperature and pH significantly facilitated dye adsorption on chemically activated carbon.
Efficient Dyeing Mechanism of Cotton/Polyester Blend Knitted Fabric
Mohammad Tofayel Ahmed,안승국 한국섬유공학회 2018 Fibers and polymers Vol.19 No.12
Innovations and modifications are the continuous processes of wet processing technology in clothing and textile industries. Due to inadequacy of water resources, consumer demands, other environmental and commercial issues, a lot of research works are being carried out throughout the world to develop the eco-friendly and cost effective textile dyeing mechanism. In this research, an attempt was taken to develop efficient dyeing method of widely used cotton and polyester blend knitted fabric by the simple modification of recognized two bath cotton/polyester blend dyeing process. The main goal of this study was to find out an alternative dyeing process to reduce the water consumption, process time and production cost replacing conventional dyeing process. In this regard, the pre-treatment and dyeing process of cotton/polyester blend fabric were modified and reduction-clearing process was eliminated without applying any extra wash off chemicals. The results revealed outstanding efficiency in terms of process time, water consumption and cost minimization maintaining all quality parameters as required. By applying modified process, the water consumption was reduced approximately by 26 %, power consumption and processing time by 15 %, and steam consumption by 3.6 %, thus overall production cost by 8 %. The proposed method could be applied to cotton/polyester knitted fabric dyeing regardless of construction, blend ratio, color, and shade %.