Cogging torque reduction of segmented HEFSM using combined technique of notching and chamfering for performance improvement

Cogging torque is one of the factors which affect the motor in terms of vibration and non-audible noise that become serious issue in flux switching machines. It is mandatory for every motor to have low cogging torque because having low cogging torque enhancing the control based on positioning of the motor in electric vehicle drive application. This project focus on reducing the cogging torque of segmented rotor HEFSM having 24S-8P using various rotor techniques configuration such as notching (NOT) and chamfering (C.H), were examined. Then a new technique has been proposed and compared using combination of NOT and C.H for reduction of cogging torque. The new proposed design configuration has been executed using 2D commercial JMAG version 15.1 at no load and load conditions for analysing the best results. Initially techniques based on NOT and C.H has reduced the cogging torque by 46% and 57% respectively of the original value of 9.5Nm. Then a new proposed technique of combination of NOT and C.H reduced almost by 60% of the initial result simultaneously. This result is considered as the best reduced technique for reduction of cogging torque of segmented HEFSM. The performance of HEFSM segmented rotor 24S-8P has been increased by using “local optimization method” based on parameter sensitivity. The total performance torque is achieved almost 55% more than the initial torque 11.07Nm. The combined technique of NOT and C.H has successfully reduced the cogging torque which improves the motor performance in terms of acoustic noise and vibration

Intergenerational Wealth Mobility in Rural Bangladesh

Unique residential history data with retrospective information on parental assets are used to study household wealth mobility in 141 villages in rural Bangladesh. Regression estimates of father-son correlations and analyses of intergenerational transition matrices show substantial persistence in wealth even when we correct for measurement errors in parental wealth. We do not find wealth mobility to be higher between periods of a person's life than between generations. We find that the process of household division plays an important role: sons who splinter off from the father's household experience greater (albeit downward) mobility in wealth. Despite significant occupational mobility across generations, its contribution to wealth mobility, net of human capital attainment of individuals, appears insignificant. Low wealth mobility in our data is primarily explained by intergenerational persistence in educational attainment.intergenerational inequality, household wealth, occupational mobility, schooling mobility, transition matrix, Bangladesh

Returns to education in Bangladesh

This paper reports labour market returns to education in Bangladesh using data from recent nationwide household survey. Returns are estimated separately for rural and urban samples, males, females and private sector employees. Substantial heterogeneity in returns is observed; e.g. estimates are higher for urban (than rural sample) and female samples (compared to their male counterparts). Our ordinary least square estimates of returns to education are robust to control for types of schools attended by individuals and selection into wage work.Education, labor market participation, sample selection, Bangladesh

Transmission bandwidth efficiency enhancement techniques

All communication channels transmit infonnation fonn one user to another using channel bandwidth mostly measured in bits/second. With the advent of latest technological tools, the bandwidth efficiency of all the channels may be enhanced beyond their normal transmission capability; mean more bits can be transmitted through the same channel. Techniques such as low bit rate encoding, variable bit rates, compression of source data, digital speech interpolation, discontinuous transmission and lost frame reconstruction are some of those signal processing techniques that can be exploited to enhance bandwidth efficiencies of the channels. In this chapter bandwidth efficiency techniques are detaile

Linear predictive coding of speech

Linear Predictive Coding (LPC) is a mathematical (signal processing) technique used to remove the redundancy from speech signals. To remove the redundancy from speech signal, is done in 1\vo stages, first stage is to remove short term correlations form the signal and the second is to remove long term correlations. The short term and long term redundancies are modelled by digital filters very precisely. This chapter is dedicated for LPC ofspeec

Poisoning the Mind: Arsenic Contamination of Drinking Water Wells and Children's Educational Achievement in Rural Bangladesh

Bangladesh has experienced the largest mass poisoning of a population in history owing to contamination of groundwater with naturally occurring inorganic arsenic. Prolonged drinking of such water risks development of diseases and therefore has implications for children's cognitive and psychological development. This study examines the effect of arsenic contamination of tubewells, the primary source of drinking water at home, on the learning outcome of school-going children in rural Bangladesh using recent nationally representative data on secondary school children. We unambiguously find a negative and statistically significant correlation between mathematics scores and arsenic-contaminated drinking tubewells at home, net of the child's socio-economic status, parental background and school specific unobserved correlates of learning. Similar correlations are found for an alternative measure of student achievement and subjective well-being (i.e. self-reported measure of life satisfaction), of the student. We conclude by discussing the policy implication of our findings in the context of the current debate over the adverse effect of arsenic poisoning on children.subjective well-being, Madrasa, drinking water pollution, Bangladesh

Digital multiplexing techniques

Multiplexing techniques are broadly classified as analogue and digital, digital being the latest. Time Division Multiplexing (TDM) and Statistical TOM are most commonly used digital multiplexing techniques. The TOM is a detenninistic method of multiplexing various sources in pre-determined fixed slots. Statistical TDM, (STDM) uses dynamic method of allocating time slots to only the active users. The dynamic nature of slot allocations enhances bandwidth utilization better than TDM however this property of STDM is always suitable for non-delay sensitive systems. For real-time and delay sensitive systems the TDM approach is the better optio

Inequality of Educational Opportunity in India: Changes over Time and across States

This paper documents the extent of inequality of educational opportunity in India spanning the period 1983-2004 using National Sample Survey (NSS) data. We build on recent developments in the literature that has operationalized concepts in the inequality of opportunity theory (including Roemer's) and construct three indices of inequality of educational opportunity using data on an adult sample. Irrespective of the index used, the state of Kerala stands out as the least unequal in terms of educational opportunities. However, even after excluding Kerala, significant inter-state divergence remains amongst the remaining states. Transition matrix analysis confirms substantial inter-temporal mobility in inequality of opportunity across Indian states. Rajasthan and Gujarat in the West and Uttar Pradesh and Bihar in the Centre experienced large-scale fall in the ranking of inequality of opportunities. However, despite being poor, Eastern states of West Bengal and Orissa made significant progress in reducing inequality of opportunity. At a region level, Southern, North-eastern and Eastern regions on average experienced upward mobility (i.e. decline in inequality of opportunity) whilst the Central region experienced downward mobility. We conclude by examining the link between progress towards equality of opportunity and poverty reduction, growth and a selection of pro-poor policies.schooling mobility, dissimilarity index, Gini of opportunity index, overlap index

Low bit rate speech coding

In recent years much work has be concentrated on encoding speech. Various coding methods are developed such as Low-Delay Codebook Excited Linear Prediction (LD-CELP), Codebook Excited Linear Prediction (CELP), Pulse Residual Excited Linear Prediction (PRELP) and others. These encoders operate at very low bit rates (4.8Kbps) as well as maintained speech quality. In this chapter some ofthese encoding algorithms are explaine