Effect of Unfolding on the Spectral Statistics of Adjacency Matrices of Complex Networks

Random matrix theory is finding an increasing number of applications in the context of information theory and communication systems, especially in studying the properties of complex networks. Such properties include short-term and long-term correlation. We study the spectral fluctuations of the adjacency of networks using random-matrix theory. We consider the influence of the spectral unfolding, which is a necessary procedure to remove the secular properties of the spectrum, on different spectral statistics. We find that, while the spacing distribution of the eigenvalues shows little sensitivity to the unfolding method used, the spectral rigidity has greater sensitivity to unfolding.Comment: Complex Adaptive Systems Conference 201

Phenomenological model for symmetry breaking in chaotic system

We assume that the energy spectrum of a chaotic system undergoing symmetry breaking transitions can be represented as a superposition of independent level sequences, one increasing on the expense of the others. The relation between the fractional level densities of the sequences and the symmetry breaking interaction is deduced by comparing the asymptotic expression of the level-number variance with the corresponding expression obtained using the perturbation theory. This relation is supported by a comparison with previous numerical calculations. The predictions of the model for the nearest-neighbor-spacing distribution and the spectral rigidity are in agreement with the results of an acoustic resonance experiment.Comment: accepted for publication in Physical Review

Market Efficiency, Time-Varying Volatility and Equity Returns in Bangladesh Stock Market

This paper empirically examines the issue of market efficiency and time-varying risk return relationship for Bangladesh, an emerging equity market in South Asia. The study utilizes a unique data set of daily stock prices and returns compiled by the authors which was not utilized in any previous study. The Dhaka Stock Exchange (DSE) equity returns show positive skewness, excess kurtosis and deviation from normality. The returns display significant serial correlation, implying stock market inefficiency. The results also show a significant relationship between conditional volatility and the stock returns, but the risk-return parameter is negative and statistically significant. While this result is not consistent with the portfolio theory, it is possible theoretically in emerging markets as investors may not demand higher risk premia if they are better able to bear risk at times of particular volatility (Glosten, Jagannathan and Runkle, 1993). While circuit breaker overall did not have any impact on stock volatility, the imposition of the lock-in period has contributed to the price discovery mechanism by reverting an overall negative riskreturn time-varying relationship into a positive one. As a policy to improve the capital market efficiency, the timely disclosure and dissemination of information to the shareholders and investors on the performance of listed companies should be emphasized.

An Econometric Model of the Role of Financial Institutions in Financing Private Investment in Pakistan

The paper examines the relationship not only between private investment and financial linkage variables but also amongst the linkage variables. It examines the effect of different policy instruments on investment to provide guidelines to monetary authorities. It shows that the private investment in Pakistan was linked with the availability rather than the price of funds

An improved routing strategy for wavelength routed WDM networks.

The routing problem in Wavelength-division multiplexing (WDM) networks, on a given logical topology, is to find an optimum scheme for data communication so that the network may handle all traffic requirements in an efficient manner and minimize the network congestion. This problem is typically solved using a Linear Programming (LP) formulation using the node-arc representation and a LP solver such as the CPLEX. As the network size increases, the time taken by a tool like CPLEX to find a solution to the routing problem becomes unacceptable. This thesis investigates a novel technique, using the arc-chain formulation for representing the logical topology, to speed up the solution of the routing problem. We use eta-factorization with the generalized upper bound (GUB) technique to solve such problems. Experiments show that our approach significantly outperforms the standard LP techniques based on a node-arc formulation, in terms of the time required to generate an optimal solution.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .K35. Source: Masters Abstracts International, Volume: 44-03, page: 1403. Thesis (M.Sc.)--University of Windsor (Canada), 2005