Open vs Closed Access Femtocells in the Uplink

Femtocells are assuming an increasingly important role in the coverage and capacity of cellular networks. In contrast to existing cellular systems, femtocells are end-user deployed and controlled, randomly located, and rely on third party backhaul (e.g. DSL or cable modem). Femtocells can be configured to be either open access or closed access. Open access allows an arbitrary nearby cellular user to use the femtocell, whereas closed access restricts the use of the femtocell to users explicitly approved by the owner. Seemingly, the network operator would prefer an open access deployment since this provides an inexpensive way to expand their network capabilities, whereas the femtocell owner would prefer closed access, in order to keep the femtocell's capacity and backhaul to himself. We show mathematically and through simulations that the reality is more complicated for both parties, and that the best approach depends heavily on whether the multiple access scheme is orthogonal (TDMA or OFDMA, per subband) or non-orthogonal (CDMA). In a TDMA/OFDMA network, closed-access is typically preferable at high user densities, whereas in CDMA, open access can provide gains of more than 200% for the home user by reducing the near-far problem experienced by the femtocell. The results of this paper suggest that the interests of the femtocell owner and the network operator are more compatible than typically believed, and that CDMA femtocells should be configured for open access whereas OFDMA or TDMA femtocells should adapt to the cellular user density.Comment: 21 pages, 8 figures, 2 tables, submitted to IEEE Trans. on Wireless Communication

Change In The Indian Accounting Profession: Three Studies Related To The Entry Of The Big Four Accounting Firms In India

This dissertation focuses on the globalization of audit markets. In particular, this dissertation is studying the entry of the Big Four accounting firms into India post-economic and political reforms of the early 1990s. The dissertation is comprised of three separate, but related studies. Each study appeals to prior research in accounting and related disciplines to examine the entry of the Big Four accounting firms in India. The first study appeals to audit market and economic research on incumbent pricing to examine ways in which local accounting firms in India adapted to the competition introduced by the Big Four accounting firms. The second study is an account of the change in the organizational field of the Indian accounting profession caused by the entry of the multinational accounting firms from 1990 to 2005 from a social constructionist perspective using the model of nonisomorphic change. The third study examines the change in the Indian accounting profession from 1990 to 2005 caused by the entry of the Big Four accounting firms in India from a critical perspective. It appeals to the theories of globalization to examine the change. Taken together, these studies attempt to provide the Big Four accounting firms useful information about the pricing strategies likely to be faced by them from local accounting firms in a new market, provide insights into the multiple roles played by professional associations in the process of radical change in the organizational field, and emphasize that globalization of accounting markets has not been accompanied by a level playing field for the local accounting profession in the globalized markets

Fingerprint Authentication System

Fingerprint is one of the most widely used biometric modality for recognition due to its reliability, non-invasive characteristic, speed and performance. The patterns remain stable throughout the lifetime of an individual. Attributable to these advantages, the application of Fingerprint biometric is increasingly encouraged by various commercial as well as government organizations. Fingerprint feature detection is to automatically and reliably extract minutiae from the input Fingerprint images. However, the performance of a minutiae extraction algorithm relies heavily on the quality of the input Fingerprint images. In order to ensure that the performance of an Fingerprint authentication system to be robust, it is essential to preprocessing Fingerprint image. This thesis describes steps involved during Fingerprint preprocessing, which improves the clarity of ridge and bifurcation structures of input Fingerprint images. After preprocessing minutiae are extracted and stored in database. Further an online Fingerprint authentication system is implemented in which elementary indexing strat- egy is used. Indexing Fingerprint data is done to identify and retrieve a small subset of candidate data from the database of Fingerprint data of individuals. Experimental work show that incorporating the online system, preprocessing algorithm, matching algorithm improves the overall response time

Interference management and decentralized channel access schemes in hotspot-aided cellular networks

A system and method are provided wherein one or more femtocell base stations are deployed within a range of a cellular base station and utilize substantially the same frequency band as the cellular base station. Each femtocell base station may be configured to employ one or more interference avoidance techniques such that coexistence between the cellular and the corresponding femtocell base station is enabled. The interference avoidance techniques employed may include use of randomized time or frequency hopping; randomly selecting a predetermined number, or identifying one or more unutilized, frequency subchannels for signal transmission; using two or more transmit and two or more receive antennas; nulling one or more transmissions in a direction of a nearby cellular base station user; handing off at least one cellular user to one of the femtocell base stations and vice versa; and/or reducing the transmission power of at least one femtocell base station.Board of Regents, University of Texas Syste

Entanglement transitions in random definite particle states

Entanglement within qubits are studied for the subspace of definite particle states or definite number of up spins. A transition from an algebraic decay of entanglement within two qubits with the total number $N$ of qubits, to an exponential one when the number of particles is increased from two to three is studied in detail. In particular the probability that the concurrence is non-zero is calculated using statistical methods and shown to agree with numerical simulations. Further entanglement within a block of $m$ qubits is studied using the log-negativity measure which indicates that a transition from algebraic to exponential decay occurs when the number of particles exceeds $m$. Several algebraic exponents for the decay of the log-negativity are analytically calculated. The transition is shown to be possibly connected with the changes in the density of states of the reduced density matrix, which has a divergence at the zero eigenvalue when the entanglement decays algebraically.Comment: Substantially added content (now 24 pages, 5 figures) with a discussion of the possible mechanism for the transition. One additional author in this version that is accepted for publication in Phys. Rev.

Heavy Quark Potential from Gauge/Gravity Duality: A Large D Analysis

The heavy-quark potential is calculated in the framework of gauge/gravity duality using the large-D approximation, where D is the number of dimensions transverse to the flux tube connecting a quark and an antiquark in a flat D+2-dimensional spacetime. We find that in the large-D limit the leading correction to the ground-state energy, as given by an effective Nambu-Goto string, arises not from the heavy modes but from the behavior of the massless modes in the vicinity of the quark and the antiquark. We estimate this correction and find that it should be visible in the near-future lattice QCD calculations of the heavy-quark potential.Comment: 22 pages, 5 Figures. v2: references added, typos corrected and, Sec. 4 rewritten with an expanded non-perturbative discussion of the corrections to the Arvis potential arising from the massless modes near the boundary of the qcd strin

Cost comparisons of seven leading brands of the Hypolipidemic drug, Rosuvastatin available in an India city

Background: Hypolipidemic drugs need to be prescribed lifelong for most of the selected patients, once started. Price variation can lead to huge financial strain on the patients, especially when cost associated issues are not considered by the prescribing medical practitioner. This study was conducted to compare the cost, to the patient, of seven most commonly prescribed preparations of different brands of Rosuvastatin ten milligram, in Kolhapur city.Methods: Authors purchased a strip of 10 capsules each of the seven leading brands of Rosuvastatin ten milligrams. The prices of the strip of 10 capsules of each of the seven chosen brands were compared. Finally, the cost of each of these seven brands for one year, was compared directly as well as using percentages. The data was collected, analysed and presented in tabular forms and figures.Results: The data of the cost of seven different brands of a single hypolipidemic drug, Rosuvastatin ten milligram shows that the cost of the costliest among the seven brands of this drug for one year is almost two times that of the cheapest brand, or in other words almost 200 percent that of the cheapest brand.Conclusions: The cost differences between the cheapest and the costliest brands were substantial. The cost of remaining five brands was dispersed in between these two extremes. India, with a major part of the population being highly concerned about the cost of medications, the prescribing medical practitioner must select the preparation wisely . The most costly preparation of Rosuvastatin ten milligram can substantially add to the financial strain on the patient’s yearly expenses. Thus, Pharmaco economic considerations must be a prime concern while making a decision to prescribe medicines, especially in a country like India