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Awareness of Operational Research in a Developing Country : Focus on Bangladesh
Rahman, Shams-ur,Smith, David K. 한국경영과학회 1990 經營 科學 Vol.7 No.2
Operational Research(OR) is little known in Bangladesh in either the academic or the business areas. However, some OR studies have been carried out in Bangladesh. These studies are scattered in various journals and documents and are not all easily accessible. In this paper an attempt has been made to bring together some of them.
Awareness of Operational Research in a Developing Coountry : Focus on Bangladesh
Rahman, Shams-ur,Smith, David K. The Korean Operations Research and Management Scie 1990 經營 科學 Vol.7 No.2
Operational Research (OR) is little in Bangladesh in either the academic or the business areas. However, some OR studies have been carried out in Bangladesh. These studies are scattered in various journals and documents and are not all easily accessible. In this paper an attempt has been made to bring together some of them.
A novel adaptive logic for dynamic adaptive streaming over HTTP
Rahman, Waqas ur,Chung, Kwangsue Elsevier 2017 Journal of visual communication and image represen Vol.49 No.-
<P><B>Abstract</B></P> <P>In this paper, we propose an estimation method that estimates the throughput of upcoming video segments based on variations in the network throughput observed during the download of previous video segments. Then, we propose a rate-adaptive algorithm for Hypertext Transfer Protocol (HTTP) streaming. The proposed algorithm selects the quality of the video based on the estimated throughput and playback buffer occupancy. The proposed method selects high-quality video segments, while minimizing video quality changes and the risk of playback interruption, improving user’s experience. We evaluate the algorithm for single- and multi-user environments and demonstrate that it performs remarkably well under varying network conditions. Furthermore, we determine that it efficiently utilizes network resources to achieve a high video rate; competing HTTP clients achieve equitable video rates. We also confirm that variations in the playback buffer size and segment duration do not affect the performance of the proposed algorithm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Throughput estimation method based on the throughput observed over past segments. </LI> <LI> Rate adaptive algorithm based on the buffer occupancy and estimated throughput. </LI> <LI> Selects high-quality video segments, while minimizing video quality changes. </LI> <LI> Minimizes the risk of playback interruption. </LI> <LI> Competing HTTP clients achieve equitable video rates. </LI> </UL> </P>
Fibrin-Enhanced Canonical Wnt Signaling Directs Plasminogen Expression in Cementoblasts
Rahman, Saeed Ur,Park, Chan Ho,Baek, Jeong-Hwa,Ryoo, Hyun-Mo,Woo, Kyung Mi MDPI AG 2017 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.18 No.11
<P>Cementum is a mineralized layer on the tooth’s root surface and facilitates the biomechanical anchoring of fibrous connective tissues as a part of tooth-supportive complexes. Previously, we observed that OCCM30 cementoblasts cultured on fibrin matrices underwent apoptosis due to fibrin degradation through the expression of proteases. Here, we demonstrated that OCCM30 on fibrin matrices (OCCM30-fibrin) enhanced canonical Wnt signaling, which directed to plasminogen expression. The OCCM30-fibrin showed higher levels of Wnt3a expression, nuclear translocation of β-catenin, and T-cell factor (TCF) optimal motif (TOP) reporter activity than the cells on tissue culture dishes (OCCM30-TCD), indicating that the OCCM30-fibrin enhanced canonical Wnt/β-catenin signaling. Also, OCCM30-fibrin expressed biomineralization-associated markers at higher levels than OCCM30-TCD, of which levels were further increased with LiCl, a Wnt signaling activator. The OCCM30 cementoblasts simultaneously showed that high levels of plasminogen, a critical component of fibrinolysis, were expressed in the OCCM30-fibrin. Activation of canonical Wnt signaling with LiCl treatment or with forced lymphoid enhancer factor 1 (LEF1)-expression increased the expression of plasminogen. On the contrary, the inhibition of canonical Wnt signaling with siRNAs against Wnt3a or β-catenin abrogated fibrin-enhanced plasminogen expression. Furthermore, there are three conserved putative response elements for the LEF1/β-catenin complex in the plasminogen proximal promoter regions (−900 to +54). Site-directed mutations and chromatin immunoprecipitation indicated that canonical Wnt signaling directed plasminogen expression. Taken together, this study suggests that fibrin-based materials can modulate functional periodontal formations in controlling cementoblast differentiation and fibrin degradation.</P>
Rahman, Saeed Ur,Oh, Joung-Hwan,Cho, Young-Dan,Chung, Shin Hye,Lee, Gene,Baek, Jeong-Hwa,Ryoo, Hyun-Mo,Woo, Kyung Mi American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.21
<P>Nanofibrous engineered matrices have significant potential in cellular differentiation and tissue regeneration. Stem cells require specific extracellular signals that lead to the induction of different lineages. However, the mechanisms by which the nanofibrous matrix promotes mesenchymal stem cell (MSC) differentiation are largely unknown. Here, we investigated the mechanisms that underlie nanofibrous matrix-induced odontoblastic differentiation of human dental pulp MSCs (DP-MSCs). An electrospun polystyrene nanofibrous (PSF) matrix was prepared, and the cell responses to the PSF matrix were assessed in comparison with those on conventional tissue culture dishes. The PSF matrix promoted the expression of Wnt3a, Wnt5a, Wnt10a, BMP2, BMP4, and BMP7 in the DP-MSCs, concomitant with the induction of odontoblast/osteoblast differentiation markers, dentin sialophosphoprotein (DSPP), osteocalcin, and bone sialoprotein, whose levels were further enhanced by treatment with recombinant Wnt3a. The DP-MSCs cultured on the PSF matrix also exhibited a high alkaline phosphatase activity and intense Alizarin Red staining, indicating that the PSF matrix promotes odontoblast differentiation. Besides inducing the expression of Wnt3a, the PSF matrix maintained high levels of β-catenin protein and enhanced its translocation to the nucleus, leading to its transcriptional activity. Forced expression of LEF1 or treatments with LiCl further enhanced the DSPP expression. Blocking the Wnt3a-initiated signaling abrogated the PSF-induced DSPP expression. Furthermore, the cells on the PSF matrix increased the DSPP promoter activity. The β-catenin complex was bound to the conserved motifs on the DSPP promoter dictating its transcription. Transplantations of the preodontoblast-seeded PSF matrix to the subcutaneous tissues of nude mice confirmed the association of the PSF matrix with the Wnt3a and DSPP expressions in vivo. Taken together, these results demonstrate the nanofibrous engineered matrix strongly supports odontoblastic differentiation of DP-MSCs by enhancing Wnt/β-catenin signaling.</P> [FIG OMISSION]</BR>
ur Rahman, Shams,Kim, Geon-Hwan,Cho, You-Ze,Khan, Ajmal Editorial Department of Journal of Communications 2018 Journal of communications and networks Vol.20 No.5
<P>The throughput of a communication system depends on the data traffic load and the available capacity to support that load. In an unmanned aerial vehicle (UAV)-based communication system, the UAV position is one of the major factor affecting the capacity available to the flows (data sessions) being served. This paper proposes a centralized algorithm for positioning UAVs to maximize the throughput of a software-defined disaster area UAV communication network. The software-defined networking controller maintains upto date information about the network topology as well as the data rate demands and paths of the flows. The proposed algorithm utilizes this information to determine the positions for the UAVs such that the total throughput is maximized. The algorithm was simulated using MATLAB. The results showed that an average throughput improvement of 26% can be achieved by optimally positioning the UAVs.</P>
Review of Types, Properties, and Importance of Ferrous Based Shape Memory Alloys
Rahman, Rana Atta Ur,Juhre, Daniel,Halle, Thorsten Materials Research Society of Korea 2018 한국재료학회지 Vol.28 No.7
Shape memory alloys(SMAs) have revolutionized the material engineering sciences as they exhibit exclusive features i.e. shape memory effect(SME) and super-elasticity. SMAs are those alloys that when deform return to their predeformed shape upon heating, they also restore their original shape by removing the load. Research on properties of newly advent of several types of ferrous based shape memory alloys(Fe-SMAs), shows that they have immense potential to be the counterpart of Nitinol(NiTi-SMA). These Fe-SMAs have been used and found to be effective because of their low cost, high cold workability, good weldability & excellent characteristics comparing with Nitinol(high processing cost and low cold workability) SMAs. Some of the Fe-SMAs show super-elasticity. Fe-SMAs, especially Fe-Mn-Si alloys have an immense potential for civil engineering structures because of its unique properties e.g. two-way shape memory effect, super elasticity and shape memory effect as well as due to its low cost, high elastic stiffness and wide transformation hysteresis comparative to Nitinol. Further research is being conducted on SMAs to improve and impinge better attributes by improving the material compositions, quantifying the SMA phase transition temperature etc. In this research pre-existing Fe-SMAs are categorised and collected in a tabulated form. An analysis is performed that which category is mostly available. Last 50 years data of Fe-SMA publications and US Patents is collected to show its importance in terms of increasing research on such type of alloys to invent different compositions and applications. This data is analysed as per different year groups during last 50 years and it was analysed as per whether the keywords exist in title of an article or anywhere in the article. It was found that different keywords related to Fe-SMAs/categories of Fe-SMAs, almost don't exist in the title of articles. However, these keywords related to Fe-SMAs/categories of Fe-SMAs, exist inside the article but still there are not too many publications related to Fe-SMAs/categories of Fe-SMAs.