Volume: 8
Number: 2
December 2010

To see an article directly, click its Title. To see abstract, click its [Abstract] link.

• Finite Difference Analysis of Variable Cross-section Fixed-hinged Columns with Non Linearity
  M.A.K Chowdhuri, R.A Hossain and Md Ashiqur Rahman
  Abstract PDF
  Finite Difference Analysis of Variable Cross-section Fixed-hinged Columns with Non Linearity
  M.A.K Chowdhuri, R.A Hossain and Md Ashiqur Rahman

  Abstract

  A column having variable cross-sections with fixed-hinged end conditions has been modelled assuming that the column material has non-symmetric responses in tension and compression. Recently, a powerful numerical scheme, based on finite difference technique, has been devised by the authors. This method is used to trace the load-deflection curves (equilibrium configuration paths) of the column that has highly non-linear stress-strain curves which are non-symmetric as well in tension and compression. The critical load is determined from the load-deflection curve using theorems of Thompson and Hunt. To utilize the fruitfulness of the devised method, superelastic shape memory alloy (SMA) is used as column materials. Experimentally obtained stress-strain curve of SMA, which is non-symmetric in tension and compression and highly nonlinear, used for determining the buckling response. To make the study more realistic initial shape imperfection has also been included and its effect on column's response has also been discussed in detail.
• DYNAMIC EQUIVALENCE OF A LARGE POWER SYSTEM USING POWER SYSTEM SIMULATOR FOR ENGINEERS (PSS/E)
  Ashik Ahmed and Md. Shahid Ullah
  Abstract PDF
  DYNAMIC EQUIVALENCE OF A LARGE POWER SYSTEM USING POWER SYSTEM SIMULATOR FOR ENGINEERS (PSS/E)
  Ashik Ahmed and Md. Shahid Ullah

  Abstract

  In this paper the step-by-step procedure of obtaining the network equivalent of a large power system using Power System Simulators for Engineers (PSS/E) is presented. Coherency among the generators of the study system is identified using the non-linear time domain simulation obtained by PSS/E. Generators with the most identical swing are considered to be coherent. Dynamic aggregation of the coherent group of generators is performed based on the Zhukov's method. The accuracy of the procedure is demonstrated by comparing the steady state and dynamic results of the original and the equivalent system. The comparisons clearly indicate excellent level of accuracy achieved from this work. The step-by-step procedure of building dynamic equivalent presented in this paper will be extremely helpful for the researchers to understand and work with the commercial PSS/E software.
• Spectral and Statistical Analysis of Human Sleep EEG Signals
  Md. Shahedul Amin, Md. Riyasat Azim, A.S.M. Shihavuddin, Md. Ashraful Hoque
  Abstract PDF
  Spectral and Statistical Analysis of Human Sleep EEG Signals
  Md. Shahedul Amin, Md. Riyasat Azim, A.S.M. Shihavuddin, Md. Ashraful Hoque

  Abstract

  Electroencephalogram (EEG) is a complex signal resulting from postsynaptic potentials of cortical pyramidal cells and an important brain state indicator with specific state dependent features. Modern brain research is intimately linked to the feasibility to record the EEG and to its quantitative analysis. EEG spectral analysis is an important method to investigate the hidden properties and hence the brain activities. Spectral analysis of sleep EEG signal provides acute insight into the features of different stages of sleep which can be utilized to differentiate between normal and pathological conditions. This paper describes the process of extracting features of human sleep EEG signals through the use of tools used for spectral analysis of conventional signals. This paper also discusses statistical analysis of human sleep EEG signals in order to detect any hidden patterns lying within the human sleep EEG signal of same kind and nature. To justify the results obtained from applying the spectral and statistical analysis tools K-Means algorithm and Receiver Operating Characteristics have been used. It analyzes.the accuracy of the system and defines the relationship between the accuracy, reliability and the amount of test data. This paper also discusses the clinical correlation associated with sleep EEG signals in brief,
• Implementation of Intelligent File Sharing in Advanced Collaborating Environment with Data Adaptation and Cache Optimization Service
  Md. Rezwanur Rahman, Tamkin Khan Av, Md. Ali Ashik Khan, Mohammad Rezwanul Huq
  Abstract PDF
  Implementation of Intelligent File Sharing in Advanced Collaborating Environment with Data Adaptation and Cache Optimization Service
  Md. Rezwanur Rahman, Tamkin Khan Av, Md. Ali Ashik Khan, Mohammad Rezwanul Huq

  Abstract

  In a collaborative environment devising an efficient file sharing and adaptation mechanism is a major challenge. This Paper shows the implementation of file sharing (upload and download) in advanced collaboration environment through a secured node from the unsecured ones, It also shows the data adaptation and cache optimization techniques to achieve the faster, more efficient and meaningful collaboration among users, It introduces a Key based registration system as well as an algorithm for Key generation to automate the registration process for slave ACE nodes. It also proposes an automated mechanism to distinguish trusted (registered) Slave ACE nodes, which are privileged for p2p file sharing under certain conditions. This approach will completely eliminate the manual intervention in the purposive node selection process. Moreover there would be a network traffic monitoring process which will radically reduce the network overhead to the master ACE node and introduce faster network collaboration in a distributive manner.