Capacity allocation in wireless communication networks : models and analyses

This monograph has concentrated on capacity allocation in cellular and Wireless Local Area Networks, primarily with a network operator’s perspective. In the introduc- tory chapter, a reference model has been proposed for the extensive suite of capacity allocation mechanisms that can be applied at different time scales, in order to influ- ence the inherent trade-offs between investment costs, network capacity and service quality. The subsequent chapters presented a number of comprehensive studies with the objective to understand the joint impact of the different control mechanisms on the network operations and service provisioning, as well as the influence of the largely uncontrollable traffic and mobility characteristics on the system- and service-level performance

How Much Evidence Should One Collect?

This paper focuses on the question how much evidence one should collect before deciding on the truth-value of a proposition. An analysis is given of a model where evidence takes the form of Bernoulli-distributed random variables. From a Bayesian perspective, the optimal strategy depends on the potential loss of drawing the wrong conclusion about the proposition and the cost of collecting evidence. It turns out to be best to collect only small amounts of evidence unless the potential loss is very large relative to the cost of collecting evidence

A CMOS four-quadrant analog current multiplier

A CMOS four-quadrant analog current multiplier is described. The circuit is based on the square-law characteristic of an MOS transistor and is insensitive to temperature and process variations. The circuit is insensitive to the body effect so it is not necessary to place transistors in individual wells. The multiplier has a large -3-dB bandwidth (50 MHz with 10-¿m transistors) and an approximately constant input impedance. The circuit was realized on a CMOS semicustom array. Measurements have shown that the nonlinearity is less than 1% at the maximum input current range and less than 0.2% when the input range is restricted to 50% of the maximu

A CMOS Wideband Linear Current Attenuator with Electronically Variable Gain

A CMOS highly linear current attenuator is described. The circuit is suited for both differential and single input currents. The current gain is electronically variable between -1 and +1 by means of two controlling currents. A simple additional circuit is described to obtain a gain that is linearly dependent on a single control current. The circuit can be used as a four-quadrant current multiplier. The current attenuator is realized in a standard 2.5 μm CMOS process using channel lengths of 5 μm. The measured nonlinearity is less than 1% over the entire input current range. Simulations indicate a feasible -3dB bandwidth of over 100 MHz

A Comparison of Soviet and US Industrial Performance: 1928-90

This paper contains estimates of comparative labour productivity levels in manufacturing for the Soviet Union and the USA. Value added was converted to a common currency by using an expenditure based unit value ratio (or purchasing power parity). Time series for value added and labour inputs were used to estimate relative Soviet/US productivity levels back to 1928. The main findings are that in 1987, Soviet value added per person employed was 24.8 per cent of American levels. Value added per hour was 26.3 per cent of the USA. Combining US and Soviet time series for output and employment together with the results of the detailed comparison of labour productivity for 1987, brought me to the conclusion that over the period 1928-89 Soviet labour productivity inproved very little relative to the US. The results of this study are partly based on Soviet datasets that were formerly not available to researchers.

Diameter of the stochastic mean-field model of distance

We consider the complete graph \cK_n on $n$ vertices with exponential mean $n$ edge lengths. Writing $C_{ij}$ for the weight of the smallest-weight path between vertex $i,j\in [n]$, Janson showed that $\max_{i,j\in [n]} C_{ij}/\log{n}$ converges in probability to 3. We extend this result by showing that $\max_{i,j\in [n]} C_{ij} - 3\log{n}$ converges in distribution to a limiting random variable that can be identified via a maximization procedure on a limiting infinite random structure. Interestingly, this limiting random variable has also appeared as the weak limit of the re-centered graph diameter of the barely supercritical Erd\H{o}s-R\'enyi random graph in work by Riordan and Wormald.Comment: 27 page

Infinite canonical super-Brownian motion and scaling limits

We construct a measure valued Markov process which we call infinite canonical super-Brownian motion, and which corresponds to the canonical measure of super-Brownian motion conditioned on non-extinction. Infinite canonical super-Brownian motion is a natural candidate for the scaling limit of various random branching objects on $\Z^d$ when these objects are (a) critical; (b) mean-field and (c) infinite. We prove that ICSBM is the scaling limit of the spread-out oriented percolation incipient infinite cluster above 4 dimensions and of incipient infinite branching random walk in any dimension. We conjecture that it also arises as the scaling limit in various other models above the upper-critical dimension, such as the incipient infinite lattice tree above 8 dimensions, the incipient infinite cluster for unoriented percolation, uniform spanning trees above 4 dimensions, and invasion percolation above 6 dimensions. This paper also serves as a survey of recent results linking super-Brownian to scaling limits in statistical mechanics.Comment: 34 page