Performance of voice over frame relay

Frame Relay (FR) represents one of the most important paradigm shifts in modern telecommunication. This technology is beginning to evolve from data only application to broad spectrum of multimedia users and potential to provide end users with cost effective transport of voice traffic for intra office communication. In this project the recent development in voice communication over Frame relay is investigated. Computer ssimulations were carried out using the powerful simulation software OPNET. Performance measures such as delays, jitter, and throughput are reported. It is evident from the results that real-time voice or video across a frame relay network providing acceptable performance is possible

Iterative turbo beamforming for OFDM based hybrid terrestrial-satellite mobile system

In the context of orthogonal frequency division multiplexing (OFDM)-based systems, pilot-based beamforming (BF) exhibits a high degree of sensitivity to the pilot sub-carriers. Increasing the number of reference pilots significantly improves BF performance as well as system performance. However, this increase comes at the cost of data throughput, which inevitably shrinks due to transmission of additional pilots. Hence an approach where reference signals available to the BF process can be increased without transmitting additional pilots can exhibit superior system performance without compromising throughput. Thus, the authors present a novel three-stage iterative turbo beamforming (ITBF) algorithm for an OFDM-based hybrid terrestrial-satellite mobile system, which utilises both pilots and data to perform interference mitigation. Data sub-carriers are utilised as virtual reference signals in the BF process. Results show that when compared to non-iterative conventional BF, the proposed ITBF exhibits bit error rate gain of up to 2.5 dB with only one iteration

Studies on growth and mortality of Cyprinus carpio (Lin.) in floating ponds

Growth and mortality rate of Cyprinus carpio (Linnaeus) under five different dietary conditions were studied in fifteen floating net cages in ponds of the Bangladesh Agricultural University Campus, Mymensingh. Growth rate was found to vary under different dietary conditions. The feed with mixture of 25% rice bran, 5% wheat bran, 30% linseed oil cake and 40% water hyacinth leaf meal exhibited the highest growth rate. The gain of log of body weight per unit increase of log of total length was significant. Significant survivals of the fishes were found

Population dynamics of Terapon jarbua (Forskal) in coastal area of Pakistani waters

Terapon jarbua is a widely distributed species in Pakistani inshore waters. It is well cherished by local coastal population. Present study is an attempt to determine some parameters of the population dynamics of the species in Pakistani waters. Analysis of data shows that the species attains asymptotic length (Loo) at 33.2 cm and have growth curve (K) of 0.62. Total mortality coefficient (Z) comes to 1. 67 per year, natural mortality coefficient (M) is estimated as 1.23 per year. The fishing mortality (F) is about 0.44 per year; whereas exploitation rate E=0.26

Growth, osmoregulation and ion accumulation in the coastal halophyte Arthrocnemum indicum under field conditions

Life cycle and population biology of a perennial halophyte Arthrocnemum indicum Willd, was studied from February 1992 to January 1993. During the 12 months, the population was exposed to great variations in soil salinity from 35 to 58 ms/cm2 and soil moisture ranging from flood to drought levels. Seasonal changes in dry weight are directly related to soil salinity stress. When salinity levels become low, the dry matter production increases. A little increase in dry weight from April to July indicates that more negative soil water potentials were limiting plant growth. Proline content increased considerably during the dry season with a corresponding increase in salinity. Water soluble oxalate did not vary much with changes in salinity

Allometric study of skeleton weight, body weight and length relationship of Euryglossa orientalis (Bl. & Schn.) (Family: Soleidae) from Karachi coast

Present study deals with the family Soleidae (common sole) Euryglossa orientalis (Bl. & Schn.) of the order Pleuronectiformis from Karachi coast. Separate equation (regression line) for describing the length weight relationships for male and female combined are justified. Allometric studies were made on skeleton weight relative to the length and the weight of the fish. The regression equation 'a' and 'b' values of standard length/skeleton weight and body weight/skeleton weight are statistically significant

Perceptions of innovation-based relationship marketing (PIRM) in the Sri Lankan retail banking sector: A qualitative study.

The purpose of this research is to investigate the “Perceptions of Innovation based Relationship Marketing” (PIRM) model based on evidence from four retails banks in Sri Lanka. From the bankers’ perspectives, the PIRM model focuses on how product innovation, process innovation and organizational innovation lead to improving relationship marketing. This research used qualitative methods using sixteen in-depth interviews in four retail banks in Sri Lanka. Four bankers were interviewed from each bank. The theory building case study approach has been adopted together with cross-case synthesis. The qualitative thematic analysis showed that bankers rely on three dimensions of innovation: product innovation, process innovation and organizational innovation, perceiving those to promote the improvement of relationship marketing. From the retail banking perspective, the PIRM model may enable better understanding of customer retention and acting as a way of promoting innovative sustainable competitive advantage

Natural Resource Rent and Financial Development Nexuses in Bangladesh: The Role of Institutional Quality

This paper examines the relationship between the development of the financial sector of the economy and natural rents. The financial sector of the economy is currently an important driver of economic growth. The study was conducted through the prism of addressing two key issues: determining the nature of the impact of natural rents on the financial development of Bangladesh; study of the role of the quality of institutional mechanisms in the relationship between natural rent and financial development of Bangladesh

Properties of proton exchange membranes poly-ethylene terephthalate (PET) films developed by gamma radiation induced grafting and sulfonation technique

Proton exchange membranes (PEMs) were developed by radiation induced grafting of styrene onto poly ethylene terephthalate (PET) and linear low density polyethylene (LLDPE) membranes using two steps technique. Subsequent sulfonation on the PET films was conducted by chlorosulfonic acid (ClSO3H). The PET films in 45% styrene solution at 1500 krad dose has found to show the highest grafting (17.4%) in both techniques while the maximum degree of sulfonation was noticed to be 9% with a soaking time 150 minutes. Surface morphology was investigated from scanning electron microgram (SEM). Proton exchange capacity (PEC) was confirmed by pH change in 0.01 M NaCl solution. Optical and electrical characteristics of the PEMs were performed by the measurements of FTIR optical absorption, electrical impedance, and electrical resistance respectively