Asymptotically optimal transmission power and rate control for CDMA channels with MF and MMSE receivers

The asymptotically combined optimal transmission power and rate control policy is derived for a DS-CDMA time varying fading channel with multiple user classes, random spreading codes and a receiver using either a conventional matched filter (MF) or a minimum mean square error (MMSE) multiuser detector. For a general objective function, the optimal policies are given by closed form functions of a single Lagrangian multiplier. The optimal policies are demonstrated by an application, where the transmission power is adapted to the channel fade variations, and the transmission rates are adapted to the tier containing the mobile. The effect of the number of tiers on the optimal transmission rate are presented for MF and MMSE receivers in an environment with Lognormal and Rayleigh fading. It is shown that with an MMSE receiver, there is a substantial increase in the total transmission rate, whereas only a negligible increase exists with a MF receiver. Zvi Rosberg received the B.Sc., M.A. and Ph.D. degrees from the Hebrew University of Jerusalem. During his graduated studies he was a senior system analyst in the Central Computing Bureau of the Israeli government, where he was one of the chief designers of a new on-line Israeli population registration system. After graduation he held a research fellowship at the Center of Operation Research and Econometric (C.O.R.E.), Belgium and a visiting assistant professorship at the department of Business Administration, University of Illinois. At 1980 he joined the Computer Science department, Technion, Israel where he was until 1990. From 1990 to 1999 he was with the Haifa Research Laboratory, Science and Technology, IBM Israel, holding a position of a Program Manager of Communication Networks. From 2000 to 2001 he was with Radware Ltd., holding the chief scientist position. During the year of 2002 he visited the ARC Special Research Centre for Ultra-Broadband Information Networks (CUBIN), University of Melbourne. Currently he is an Associate/Professor at the Department of Communication Systems Engineering, Ben Gurion University, Beer-Sheva. Since 1980 he held summer research positions and a two year visiting position in IBM Thomas J. Watson Research Center, Yorktown Heights. He also had summer research positions in the Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, Department of Electrical Engineering and Computer Science, University of California, Berkeley, the Radio Communication Systems, Royal Institute of Technology (KTH) in Stockholm, the ARC Special Research Center for Ultra-Broadband Information Networks (CUBIN), University of Melbourne, and the Department of EEE, City University, Hong Kong. Presently, he is serving on the editorial board of the Wireless Networks (WINET) and the International Journal of Communication Systems. His research interest, where he has published numerous papers, include: Narrowband and spread spectrum wireless communication, Radio resource allocation and planning in cellular networks, Scheduling in wireless networks, Optical and ultra high speed networks, Control in queueing networks, Analysis of algorithms in communication and computing systems and Internet technologies     

The minimum test set problem for circuits with nonreconvergent fanout

The problem of computing the minimum size of a test set for a combinational circuit is considered. It is known that the minimum test set size of a combinational circuit can be determined in polynomial time for fanout free circuits, while even for circuits with non-reconvergent fanout, the minimum test set size problem is NP-Hard. We extend the class of circuits for which a minimum test set can be constructed in polynomial time to include a class of circuits with fanout, called restricted fanout circuits. Restricted fanout circuits are characterized using an undirected graph describing the structure of the circuit. The graph for these circuits must be free of (undirected) cycles. In addition, the paper demonstrates a novel application of dynamic programming to test generation problems.Formerly with the Electrical Eng. and Computer Science Depts. at the Technion, Haifa 32000, Israel.     

Gradual removals in cellular PCS with constrained power control and noise

In this paper we study themobile removal problem in a cellular PCS network where transmitter powers are constrained and controlled by a Distributed Constrained Power Control (DCPC) algorithm. Receivers are subject to non-negligible noise, and the DCPC attempts to bring each receiver's CIR above a given target. To evaluate feasibility and computational complexity, we assume a paradigm where radio bandwidth is scarce and inter-base station connection is fast. We show that finding the optimal removal set is an NP-Complete problem, giving rise for heuristic algorithms. We study and compare among three classes of transmitter removal algorithms. Two classes consist of algorithms which are invoked only when reaching a stable power vector under DCPC. The third class consist of algorithms which combine transmitter removals with power control. These areOne-by-one Removals, Multiple Removals, andPower Control with Removals Combined. In the class of power control with removals combined, we also consider a distributed algorithm which uses the same local information as DCPC does. All removal algorithms are compared with respect to their outage probabilities and their time to converge to a stable state. Comparisons are made in a hexagonal macro-cellular system, and in two metropolitan micro-cellular systems. ThePower Control with Removals Combined algorithm emerges as practically the best approach with respect to both criteria.This research has been done while the 2nd author was visiting at the Royal Inst. of Tech. under a grant from ISS '90 foundation, Sweden.     

A mechanistic study of methyl parathion hydrolysis by a bifunctional organoclay

The mechanism for the hydrolysis of methyl parathion (MP) by a bifunctional quaternary-ammonium based long-chained organclay(LCOC) containing an alkylamine (-CH2CH2-NH2) headgroup was elucidated. The pathway of the catalytic hydrolysis of methyl parathion by the LCOC was defined by following the effect of replacing H20 with D20, by replacing the primary amino headgroup by a tertiary amino group, and by a detailed mathematical analysis of the proposed reaction scheme. A phosphorothioate isomer of MP was formed in the presence of the LCOC as an intermediate reaction product, initially increasing in concentration and then disappearing. The isotope effect was minimal and substituting a tertiary amine in the LCOC increased the rate of MP hydrolysis. A mechanism is proposed in which hydrolysis of MP can proceed via both a direct route (specific base hydrolysis) and through the formation of the isomer which then undergoes specific base hydrolysis more rapidly than the parent MP. The relative importance of each pathway is a function of pH with the direct hydrolysis of MP being predominant at higher pH values (pH > 10) and the isomer intermediate pathway predominating at lower pH values (pH approximately 8-10).     

Correction to diamond et al. (2010).

Reports an error in "Ongoing traumatic stress response (OTSR) in Sderot, Israel" by Gary M. Diamond, Joshua D. Lipsitz, Zvi Fajerman and Omit Rozenblat (Professional Psychology: Research and Practice, 2010[Feb], Vol 41[1], 19-25). In the article “Ongoing Traumatic Stress Response (OTSR) in Sderot, Israel,” by Diamond, Lipsitz, Fajerman and Rozenblat (Professional Psychology: Research and Practice, 2010, Vol. 41, No. 1., pp. 19–25), due to a production error, the last author’s name was misspelled in the byline and the author note. The correct spelling is Ornit Rozenblat. (The following abstract of the original article appeared in record 2010-02467-003.) In Sderot, a small city in southern Israel, seven years of continuous missile attacks have led to dramatic increases in treatment seeking for anxiety symptoms. For some clients, the clinical picture is consistent with a diagnosis of post traumatic stress disorder (PTSD). For other clients, however, the onset and constellation of symptoms are less typical of PTSD. In these cases, anxiety symptoms seem to evolve gradually and be associated with ongoing, daily stress about imminent attacks, rather than with a discrete, past traumatic event. Much of their avoidance behavior is reality based. They report hyperarousal, severe distress, and loss of control during and immediately following actual missile attacks. However, they are less likely to exhibit reexperiencing symptoms. Furthermore, in contrast to the typical presentation of PTSD, their symptoms tend to diminish dramatically or completely resolve when they are no longer within harm’s way. We suggest that this clinical presentation may be best understood as an ongoing traumatic stress response (OTSR), rather than PTSD or PTSD symptoms. We consider diagnostic features which discriminate between these two phenomena as well as implications for treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbial and algal oils: Do they have a future for biodiesel or as commodity oils?

We review the prospects of using yeasts and microalgae as sources of cheap oils that could be used for biodiesel. We conclude that yeast oils, the cheapest of the oils producible by heterotrophic microorganisms, are too expensive to be viable alternatives to the major commodity plant oils. Algal oils are similarly unlikely to be economic; the cheapest form of cultivation is in open ponds which then requires a robust, fast‐growing alga that can withstand adventitious predatory protozoa or contaminating bacteria and, at the same time, attain an oil content of at least 40% of the biomass. No such alga has yet been identified. However, we note that if the prices of the major plant oils and crude oil continue to rise in the future, as they have done over the past 12 months, then algal lipids might just become a realistic alternative within the next 10 to 15 years. Better prospects would, however, be to focus on algae as sources of polyunsaturated fatty acids.     

Self-calibration and mirror center offset elimination of a multi-beam laser tracking system

New methods for the self-calibration of a laser tracking coordinate measuring machine are reported in this paper. Proper calibration of a laser tracking system is essential prior to using such a device for coordinate measuring. The task is nontrivial in the absence of other measurement systems of comparable accuracy. One has to rely on a self-calibration strategy. Two calibration methods, one based on a four-tracker system and the other based on three trackers combined with precision planes to constrain the target motion, are proposed. Iterative optimization algorithms are developed. A basic assumption for these calibration methods is that there is no tracking mirror center offset. Error analysis presented in this paper reveals that measurement errors due to mirror center offsets are significant. Therefore before calibrating the laser tracking system, the mirrors must be adjusted so that the laser beams hit the mirror centers. The adjustment is a tedious manual task. In the FAU laser tracking machine, an adjustment procedure which employs a four quadrant detector has been devised for the elimination of tracking mirror center offsets. Simulation and experimental results are presented to demonstrate the effectiveness of the suggested methods.     

Sigmund Freud and Minna Bernays: Primal curiosity, primal scenes, primal fantasies--And prevarication.

Attacks on Freud's theories on sexuality began when Freud launched his studies on hysteria in the last decade of the 19th century and are still ongoing. The latest cavil is embedded in a sensation exploded in the summer of 2006 by Franz Maciejewski of Heidelberg, Germany. It was publicized in front-page reportage by New York Times columnist Ralph Blumenthal (2006): "A Century-Old Swiss Hotel Log Hints at an Illicit Desire That Dr. Freud Didn't Repress," additionally editorialized as adequate "to impugn [Freud's] reputation" (p. A4). In this article, arguments ad hominem, bordering on Freud-bashing, concerning Freud as a person and his relationship with his sister-in-law Minna Bernays, are separated from arguments ad rem, regarding the merits of Freud's theory of the Oedipus complex. The evidence presented by Maciejewski is found to be flawed and to not rise above the level of conjecture. Similarly, his construction that the alleged sexual affair between Freud and his sister-in-law was tantamount to incest, and thus source of theory of the Oedipus complex, has no standing either. (PsycINFO Database Record (c) 2010 APA, all rights reserved)