BES Journal

An Idea of Dynamic Radio Spectrum Management and Charging Paradigm Issues in Bangladesh
Md. Kabir Uddin , Mohammad Noor Nabi , Farruk Ahmed and M Abdus Sobhan
At this time, a little understanding on how such a dynamic trading system will operate so as to make the system feasible under economic terms. Dynamic Spectrum Access concept will allow the radio spectrum to be traded in a market like scenario allowing Wireless Service Providers (WSPs) to lease chunks of spectrum on a short-term basis. The market mechanisms of this will lead to competition among WSPs where they not only compete to acquire spectrum but also attract and retain users. The monitoring system of Synthetic is a good complement when used with passive monitoring that together will help provide visibility on application health during off peak hours when transaction volume is low. Several concepts reviewed briefly that are central to the design of spectrum management paradigms emphasizing on spectrum charging and allocation. These include (i) BTRC auctions (ii) Single-unit auctions (iii) peak Load Charging. In line with these concepts and models, the author proposed a spectrum charging paradigm for the Harmonized Usages Band (HUB) operated by the spectrum broker for homogeneous CDMA networks. In particular, examines existing spectrum charging model and proposed spectrum charging paradigm for harmonized DSA.
A Dynamic Message-length-based Caesar-cipher Encryption/Decryption Process for Secured Electronic Transactions
Afia Khanom, Abu Toub, Rabeya Sultana, Md. Abdul Mukib and Dr. M. Ismail Jabiullah
A message-length-based Caesar cipher generation technique has been designed, developed and implemented for secure communication of the electronic documents. The encryption/decryption key is found by calculating the number of plaintext that is to be transmitted through the electronic transactions. In this paper, an improved Caesar cipher generation technique based on symmetric key encryption algorithm has been proposed that uses ASCII values of input text as the encryption process and length of text message to encrypt the text data. First, take a message as character that is to be sent to the destination and counts the length of the message. Then these characters convert in equivalent ASCII code. It adds length of message and the ASCII code. Convert this value in binary number in nine bit and save it in data file. This data file called file of cipher text and this process is called encryption. This produced data in this process is called cipher text and is to be sent to the destination for the recipient. In the receiving end, the reverse process is performed for retrieving the plaintext of the message. Here, message-length is dynamically changeable and establishes better security than that of the conventional Caesar cipher process. It can be applied in any practical cryptographic process or lab works.
Electricity Consumption Reduction for Battery Operated Auto Rickshaws through PV Based CNG Station
Md. Mahmudul Hasan and Md. Ali Asgar
People all over the world have keen interest to look for a new way for leading a comfortable life. Accordingly various technologies have been invented in transport system. Battery operated Auto-rickshaws are a motorized version of the traditional pulled rickshaw. It is found that Bangladesh is now overwhelmed with battery operated auto-rickshaws and it is an essential form of urban transport. In this paper, as a transport mode, an analysis in using battery operated auto-rickshaw is studied pragmatically and an illustration is provided technically and financially. Results show that the battery-run auto-rickshaw has been consuming a substantial amount of electricity daily from the national grid. An effective way of using PV based CNG station has been given to reduce consumed power from our national grid by a comparative analysis through this paper.
Blackouts in South Asia Perspective of Bangladesh: Observation and Recommendation
Md. Rokonuzzaman and Mohammed Hossam-E-Haider
Though Bangladesh is considered one of the most energy-poor nations, with one of the lowest per capita electricity consumption rates in the world and has tried to improve its energy situation, extending access to electricity to about 3.45 million more people since 2008. But the increasing gap between the demand and supply of electricity has been a matter for concern. The oldest transmission lines system and conventional power skeleton which is one of the most important issues for that causing blackout. Since the power system is a non linear system and changes its operation continuously for that it is very challenging and uneconomical to make the whole system be stable and keep disturbances free. This instability causes large scale blackouts. The Russian experience to facing blackout is one of the proven and comprehensively field-testes, giving concentration on their recommendation this paper is representing a lists of good collection of wide spread power system blackouts that happened in the beginning from 21st century in south Asian territory including authors recommendation perspective of Bangladesh.
Security Aspects of Re-configurable FPGA based Crypto-system
Mohammad Noor Nabi , Md. Shafiul Alam and Farruk Ahmed
The re-configurability of FPGAs makes them better option for system design compared with ASICs, which are costly to develop. The implementation of crypto-system on FPGA is immensely accepted in different research and development forums. FPGAs deliver enhanced performance and modules, like 32-bit soft processors, DSP modules, and high performance interfaces. Recent secure systems use SRAM based FPGAs with few security aspects form manufactures. This paper addresses few security problems of FPGA based design of Crypto- system. In this paper we investigate different security problems in using FPGA for secure system. Few countermeasures are proposed to overcome these security risks.
Parametric Study On Subwavelength Plasmonic Nanostructure For Enhanced Optical Transmission
Md. Zahir Uddin Suja, Sunayna Binte Bashar, M. L. Palash and Subrata Das
This work deals with one of the astonishing property of light propagation through subwavelength aperture array i.e. the enhanced optical transmission (EOT). The design, construction and simulation of metallic nanostructure have been studied well within visible region (441 THz) to generate the transmission spectrum. An array of square subwavelength apertures in gold (Au) film deposited on SiO2 substrate has been designed with commercial simulation software optiFDTDTM 10 to observe the enhanced optical transmission. The EOT through this periodic subwavelength aperture depends on several parameters. Among those parameters - lattice periodicity, aperture width, metal thickness and refractive index (RI) of the surface dielectric medium were our point of interest. The parametric study on EOT has been performed on that designed structure and both quantitative and qualitative analyses have been addressed. Among the observations, the most important implication is that EOT has linear dependency on the aperture width and metal thickness. The transmission efficiency falls about 76% when the gold thickness varied from 100 nm to 250 nm with constant aperture width of 200 nm. This indicates that metal thickness is the most prominent factor in enhanced transmission. The study on the complicated nature of these generated spectra could provide significant insight into the use of these films for displays, spectroscopic substrates, or near-field parallel imaging arrays.
On the Single Electron Transistor
Muhibul Haque Bhuyan
Due to the fundamental size limitations of the transistor, single electron transistor (SET) has been playing an important role in nano technology and attracting researchers’ interests. It has been demonstrated that, whereas a conventional transistor turns on only once as electrons are added to it, submicron size transistors, isolated from their leads by tunnel junctions, turn on and off again every time an electron is added. This unusual behavior is primarily the result of the quantization of charge and the Coulomb interaction between electrons on the small transistor. In this review paper, history, basic theories and few applications of single electron transistor are discussed to generate interests of young researchers on SET.
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