Causes of Accident at Construction Sites in Bangladesh

Bangladeshi construction industry suffers more safety issues than other developing countries in the world. Among many of these, accidents at the construction site go far beyond and shape a horrific figure of death every year. The aims of this study are to identify and prioritize the causes of accidents. This study also analyses and discusses causes of accident at the construction site in Bangladesh. A widespread literature review and open discussion took place to identify the causes and design the questionnaire. The questionnaire-based survey was used to elicit the attitude of four stakeholders such as workers, owners, consultants and contractors towards the causes of accident. Mean and relative importance index (RII) were used to determine the rank of causes, and Statistical Package for the Social Sciences (SPSS) 23 was used to perform the data validation test. This study identifies 77 causes under 14 major groups and ranked them based on the mean and RII. The top five major groups of causes are management-, consultant-, technology-, labour- and contractor- related causes. The top five causes are unawareness of safety-related issue, lack of personal protective equipment, lack of safety eliminating/avoiding design, unfit equipment, lack of knowledge and training on equipment. This study will help the project participants and authorities to know and understand the various characteristics and linkage of causes of construction accidents to improve the construction safety management. It contributes to the body of knowledge, as it reveals for the first time the causes of accidents in the Bangladeshi construction industry

Civil Society of Bangladesh: Depoliticized in Working Agenda but Politicized in Power Relation

The concepts of depoliticization and politicization are opposite in nature but they coexist in the context of the Bangladeshi development paradigm. Civil society organizations (CSOs) are depoliticized in their working agenda and this is convenient for the state, the market and even for the CSOs themselves because they do not challenge anyone. Nevertheless, this position renders the CSOs more prone to politicization in accordance with party politics. Ultimately Bangladesh is suffering from the democratization process despite the huge number of CSOs. This study is based on an extensive survey of 1,005 CSOs in Dhaka, Bangladesh, conducted by means of structured questionnaires through direct interviews in 2006 and 2007. 要旨 非政治化と政治化の概念はまったく相反するものだが、バングラデシュの開発パラダイムの文脈では共存している。市民社会団体 (CSO) の活動方針は非政治的であり、そのことは国家、市場、さらにCSOそのものにとっても好都合である。なぜなら、誰かに反抗することはないからである。しかし、その立場はかえって、CSOが政党政治に迎合して、政治的になってしまう傾向をより強める。結局バングラデシュは、膨大な数のCSOがあるにもかかわらず、民主化のプロセスに苦しんでいる。本研究は、2006年と2007年に行った直接面談による構造化アンケートによって、ダッカ (バングラデシュ) の1,005のCSOを広範に調査した結果に基づく

Robust Resource Allocation to Secure Physical Layer Using UAV-Assisted Mobile Relay Communications in 5G Technology

The unmanned aerial vehicles (UAVs) are also known as drones. Recently, UAVs have attracted the next generation researchers due to their flexible, dynamic, and cost-effective deployment, etc. Moreover, the UAVs have a wide range of application domains, such as rescue operation in the remote area, military surveillance, emergency application, etc. Given the UAVs are appropriately deployed, the UAVs provide continuous and reliable connectivity, on-demand, and cost-effective features to the desired destination in the wireless communication system. Thus, the UAVs can be a great choice to deploy as a mobile relay in co-existence with the base stations (BSs) on the ground to serve the 5G wireless users. In this thesis, the UAV-assisted mobile relay (UAV-MR) in the next generation wireless networks has been studied, which also considers the UAV-MR physical layer security. The proposed system also considers one ground user, one BS on the ground, and active presence of multiple eavesdroppers, situated nearby the ground user. The locations of these nodes (i.e., the ground user, the BS, and the eavesdroppers) are considered fixed on the ground. Moreover, the locations of the eavesdroppers are not precisely known to the UAV-MR. Thus, this thesis aims to maximize the achievable secrecy rate, while the BS sends the secure information to the ground user via the UAV-MR. However, the UAV-MR has some challenges to deploy in wireless networks, such as 3D deployment, robust resource allocation, secure UAV-MR to ground communication, the channel modeling, the UAV-MR flight duration, and the UAV-MR robust trajectory design, etc. Thus, this project investigates the UAV-MR assisted wireless networks, which addresses those technical challenges to guarantee efficient UAV-MR communication. Moreover, the mathematical frameworks are formulated to support the proposed model. An efficient algorithm is proposed to maximize the UAV-MR achievable secrecy rate. Finally, the simulation results show the improved performance for the UAV-MR assisted next-generation networks

The application of SOA for dispersion management of 2D-WH/TS codesin incoherent OCDMA system

In high data rate optical fibre communication networks, dispersion phenomenon plays a pivotal role. It is important to investigate the dispersion effects in a multi-wavelength picosecond optical code division multiple access (OCDMA) system. This research is focused on the analysis of the effects of fibre dispersion on the OCDMA autocorrelation; and how these effects can be resolved in a tuneable way so that the originally recovered OCDMA autocorrelation function at the decoder receiver can be revived without further manual adjustment of fibre (SMF-28) cable lengths.;The environmental effects and the subsequent mitigation process are also investigated further in this research. The chirp in OCDMA is examined experimentally and analytically in an initiative to find the more in-depth understanding of finely tuneable chromatic dispersion (CD) compensation technique in a coarsely compensated link by using semiconductor optical amplifier (SOA). A practical investigation was carried over a partially CD compensated 17 km bidirectional testbed between the University of Strathclyde and the University of Glasgow to perform the fine-tuning of CD adjustment using SOA.;A 19.5 km SMF-28 fibre spool was also used in an environmental chamber to investigate the temperature induced dispersion effects and subsequent mitigation. The tuneable dispersion compensation measures are vital to ensure the high data rate optical communication using an all-optical approach in future data network end-points where the advantages of ultra-high speed optical communication bandwidth are at present disrupted due to opto-electronic conversions commonly known as 'electronic bottlenecks'.In high data rate optical fibre communication networks, dispersion phenomenon plays a pivotal role. It is important to investigate the dispersion effects in a multi-wavelength picosecond optical code division multiple access (OCDMA) system. This research is focused on the analysis of the effects of fibre dispersion on the OCDMA autocorrelation; and how these effects can be resolved in a tuneable way so that the originally recovered OCDMA autocorrelation function at the decoder receiver can be revived without further manual adjustment of fibre (SMF-28) cable lengths.;The environmental effects and the subsequent mitigation process are also investigated further in this research. The chirp in OCDMA is examined experimentally and analytically in an initiative to find the more in-depth understanding of finely tuneable chromatic dispersion (CD) compensation technique in a coarsely compensated link by using semiconductor optical amplifier (SOA). A practical investigation was carried over a partially CD compensated 17 km bidirectional testbed between the University of Strathclyde and the University of Glasgow to perform the fine-tuning of CD adjustment using SOA.;A 19.5 km SMF-28 fibre spool was also used in an environmental chamber to investigate the temperature induced dispersion effects and subsequent mitigation. The tuneable dispersion compensation measures are vital to ensure the high data rate optical communication using an all-optical approach in future data network end-points where the advantages of ultra-high speed optical communication bandwidth are at present disrupted due to opto-electronic conversions commonly known as 'electronic bottlenecks'

Production of Acidic protease using Submerged Fermentation by Rhizopus arrhizus

The study is concerned with utilize whey of milk factory as a carbon source for the production of protease. The project was planned to produce maximum protease from whey by Rhizopus arrhizus at pH 4 and 37 °C temperature. Growth media employed to culture Rhizopus arrhizus for the production of enzyme were developed and fermentation conditions was optimized through various trials. Substrate water ratio, different nitrogen sources and concentration of nitrogen source were optimized. The fermented materials were harvested after 72 hours. These were filtered and centrifuged at 10,000 rpm at -10 °C. The filtrates were subjected to enzyme assay. Absorbance of the enzyme sample was determined at 700 nm on spectrophotometer. It was observed that 90% Whey and 2.5% cotton seed meal enhanced the production of protease by Rhizopus arrhizus. Maximum enzyme activity was observed (149.26 IU/ml/min) in flask level at pH 4 and 37 °C temperature. These optimized conditions of growth media was again used in Air-Lift fermenter and determined the activity (169.78 IU/ml/min) that is greater than flask level. This is due to proper aeration and proper temperature in Air-lift fermenter.   Keywords: Acidic protease, Air-lift fermentor, submerged fermentation and Rhizopus arrhizus

Recent advances in all-optical signal processing for performance enhancements of OCDMA interconnects

The demand for data rates increases presents a great technological challenge to the well-established CMOS electronics. As a result, the electronic signal processing in optical interconnects became the stumbling block in supporting these growing demands. In this paper we will discuss and demonstrate our recent results which enable to overcome some of the challenges in OCDMA-based interconnects via implementation of silicon photonics

Photonic platform and the impact of optical nonlinearity on communication devices

It is important to understand properties of different materials and the impact they have on devices used in communication networks. This paper is an overview of optical nonlinearities in Silicon and Gallium Nitride and how these nonlinearities can be used in the realization of optical ultra-fast devices targeting the next generation integrated optics. Research results related to optical lasing, optical switching, data modulation, optical signal amplification and photo-detection using Gallium Nitride devices based on waveguides are examined. Attention is also paid to hybrid and monolithic integration approaches towards the development of advanced photonic chips