Poisson approximation for excursions of adaptive algorithms with alattice state space

This paper analyzes excursions of adaptive algorithms (such as the LMS) with a lattice state space. Under certain conditions on the input and disturbance statistics, the parameter estimate error forms a Markov chain. The approximations are valid if this chain has a strong tendency toward an equilibrium point. The distribution of the number of excursions in n units of time is approximated by a Poisson distribution. The mean and distribution of the time of the occurrence of the first excursion are approximated by those of an exponential distribution. Expressions for the error in the approximations are also derived. The approximations are shown to hold asymptotically as the excursion-defining set converges to the empty set. All the parameters required for the approximations and all expressions for the error in the approximations are calculable in a relatively straightforward manner     

Decentralized robust set-valued state estimation in networked multiple sensor systems

This paper addresses a decentralized robust set-valued state estimation problem for a class of uncertain systems via a data-rate constrained sensor network. The uncertainties of the systems satisfy an energy-type constraint known as an integral quadratic constraint. The sensor network consists of spatially distributed sensors and a fusion center where set-valued state estimation is carried out. The communications from the sensors to the fusion center are through data-rate constrained communication channels. We propose a state estimation scheme which involves coders that are implemented in the sensors, and a decoder–estimator that is located at the fusion center. Their construction is based on the robust Kalman filtering techniques. The robust set-valued state estimation results of this paper involve the solution of a jump Riccati differential equation and the solution of a set of jump state equations.     

Decentralized control of multi-agent systems for swarming with a given geometric pattern

This paper addresses a problem of cooperative formation control of a network of self-deployed autonomous agents. We propose a decentralized motion coordination control for the agents so that they collectively move in a desired geometric pattern from any initial position. There are no predefined leaders in the group and only local information is required for the control. The control algorithm is developed using the ideas of information consensus, and its effectiveness is illustrated via numerical simulations.     

Resilience Assessment of Water Resources System

The resilience perspective, which emphasizes the integrated, systemic concept of human and nature interactions, is increasingly used as an approach for understanding the dynamic of social-ecological system. As the water resources system (WRS) is a social-ecological system, resilience thinking such as Holling??s adaptive cycle has been adopted as a fundamental unit for understanding the water resources system dynamics in this paper. In the adaptive cycle of WRS, the likelihood shift among different phases largely depends on resilience value; and a quantitative method for estimating the resilience of WRS is proposed. The method is related to the degree of change and characteristics of the WRS, and has been applied to identify the phase of WRS in every city in Zhejiang province, China. The results of resilience assessment have also been discussed in terms of adaptive cycle.     

Semiconducting Carbon Nanotubes for Improved Efficiency and Thermal Stability of Polymer–Fullerene Solar Cells

The effects of the incorporation of semiconducting single‐walled nanotubes (sc‐SWNTs) with high purity on the bulk heterojunction (BHJ) organic solar cell (OSC) based on regioregular poly(3‐hexylthiophene‐2,5‐diyl):[6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (rr‐P3HT:PCBM) are reported for the first time. The sc‐SWNTs induce the organization of the polymer phase, which is evident from the increase in crystallite size, the red‐shifted absorption characteristics and the enhanced hole mobility. By incorporating sc‐SWNTs, OSC with a power conversion efficiency (PCE) as high as 4% can be achieved, which is ≈8% higher than our best control device. A novel application of sc‐SWNTs in improving the thermal stability of BHJ OSCs is also demonstrated. After heating at 150 °C for 9 h, it is observed that the thermal stability of rr‐P3HT:PCBM devices improves by more than fivefold with inclusion of sc‐SWNTs. The thermal stability enhancement is attributed to a more suppressed phase separation, as shown by the remarkable decrease in the formation of sizeable crystals, which in turn can be the outcome of a more controlled crystallization of the blend materials on the nanotubes.     

Quantitation of spironolactone in the presence of canremone using high-performance liquid chromatography

Two stability-indicating high-performance liquid chromatography methods have been developed to quantify spironolactone in the presence of its product(s) of decomposition. Both methods are accurate and precise with percent relative standard deviation of 0.7 based on 5 readings using microC₁₈ column and 0.9 using microphenyl column. By using different wavelengths, the sensitivity of the methods to quantify spironolactone or canrenone (the major product of decomposition of spironolactone) can be increased many times. Spironolactone appears to be relatively stable between pH values of about 3.4-5.2. In the acidic pH, the decomposition is slower than on the basic side of the pH. Even at pH 7.3, the decomposition was about 3.1 times faster than at pH 2.3.     

The use of structural equation modeling in assessing the quality of marital observations.

The authors examine traditional analytic approaches to assessing the quality of observational measures and suggest a structural equation modeling (SEM) approach that extends the multitrait-multimethod tradition to assess both reliability and validity of observational data. Drawing on observations of hostility and coercion in marital interactions obtained with the Iowa Family Interaction Rating Scales (J. Melby et al., 1990), the authors illustrate the use of SEM as a means to evaluate estimates of psychometric properties of both observational ratings and family member reports within the same analytic framework, thereby providing more comparable assessments across study informants. The results demonstrate the utility of this approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tijuana Case Study Tactics of Invasion: Manufactured Sites

Teddy Cruz describes how his practice in San Diego has used its experience of Mexican/US border conditions to inform a project of ‘urban acupuncture’ that has the potential to bridge the enormity of a transnational divide that exists between two adjacent communities. In essence a simple prefabricated aluminium frame, Manufactured Sites could provide the much-needed, small-scale infrastructures and services for favela-like settlements. Copyright © 2005 John Wiley & Sons, Ltd.     

Pore structure characterization of cement pastes blended with high-volume fly-ash

The pore structure of cement pastes incorporating fly-ash was evaluated during their hydration process through gravimetry method, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption (NAD) methods. The pore structure of samples is characterized by the total porosity, pore size distribution (PSD), pore internal surface area as well as characteristic pore sizes. The correlation between the hydration process and the formed pore structure is investigated. The results indicate that: (i) w/b ratios have determinant impact on all characteristics of pore structure; (ii) fly-ash replacement ratio can influence the pore structure significantly at early age but this influence becomes less important with sample age by fly-ash hydration process; (iii) the total porosity and specific surface area are well correlated with the chemical kinetics of hydration through hydration degree or the formed gel/space ratio but the critical pore size is rather independent on the chemical kinetics.     

X-ray microbeam transmission/fluorescence method for non-destructive characterization of tungsten coated carbon materials

Tungsten erosion, its subsequent transport and redeposition are of great interest, because a full tungsten divertor is foreseen to be used during the deuterium–tritium operational phase of ITER. The erosion of tungsten and carbon marker layers was extensively studied in the outer divertor of ASDEX Upgrade (AUG), and work is currently in progress to completely replace the existing JET CFC tiles with tungsten-coated tiles within the JET ITER-like wall project. The need for fast and non-destructive method which allows the quantitative determination of the thickness of a tungsten coating on a carbon material on large areas led us to evaluate a combined absorption/fluorescence X-ray (XRTF) technique. The method can provide fast analysis, high spatial resolution and a material selective detection of deposited layers and inclusions. It was applied on W coated fine grain graphite (FGG) tiles from AUG's divertor. It is proved that the method is able to provide information about the uniformity of the tungsten coating on a graphite or CFC substrate whilst the technique can be used to determine the thickness of the tungsten and other marker materials coatings. It represents a unique instrument for the post-mortem analysis of the coatings.