Fast blind estimation algorithm for Hamming codes parameters

An algorithm is proposed for fast blindly estimating the length, the starting point and the parity-check matrix of the hamming code. First, an intercepted matrix is built by the data received, and by exploiting an assumed number of parity-check digits and the assumed starting point of the hamming code. Then, a parity-check matrix is obtained by the assumed primitive polynomial, and when all its row-vectors are dual codes of the intercepted matrix, the hamming code parameters could be estimated. Moreover, a theoretical analysis of the proposed algorithm is made. Simulation results verify the good performance of the proposed method.     

Experimental studies of the shear behaviour and strength of lipped channel beams with web openings

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. Current practice in flooring systems is to include openings in the web element of floor joists or bearers so that building services can be located within them. Shear behaviour of LCBs with web openings is more complicated while their shear strengths are considerably reduced by the presence of web openings. However, limited research has been undertaken on the shear behaviour and strength of LCBs with web openings. Hence a detailed experimental study involving 40 shear tests was undertaken to investigate the shear behaviour and strength of LCBs with web openings. Simply supported test specimens of LCBs with aspect ratios of 1.0 and 1.5 were loaded at mid-span until failure. This paper presents the details of this experimental study and the results of their shear capacities and behavioural characteristics. Experimental results showed that the current design rules in cold-formed steel structures design codes are very conservative for the shear design of LCBs with web openings. Improved design equations have been proposed for the shear strength of LCBs with web openings based on the experimental results from this study.     

A new paradigm for parameter estimation in system modeling

In this paper, we consider a basic problem in system identification, that of estimating the unknown parameters of a given model by using input/output data. Available methods (extended Kalman filtering, unscented Kalman filtering, particle filtering, maximum likelihood, prediction error method, etc.) have been extensively studied in the literature, especially in relation to consistency analysis. Yet, other important aspects, such as computational complexity, have been somewhat overlooked so that, when such methods are used in practical problems, remarkable drawbacks may arise. This is why parameter estimation is often performed using empirical procedures. This paper aims to revisit the issue of setting up an estimator that is able to provide reliable estimates at low computational cost. In contrast to other paradigms, the main idea in the new introduced two‐stage estimation method is to retrieve the estimator through simulation experiments in a training phase. Once training is terminated, the user is provided with an explicitly given estimator that can be used over and over basically with no computational effort. The advantages and drawbacks of the two‐stage approach as well as other traditional paradigms are identified with an illustrative example. A more concrete example of tire parameter estimation is also provided. Copyright © 2012 John Wiley & Sons, Ltd.     

A methodology for predicting regional freight traffic in developing countries

The prime concern of transportation planners in developing countries is how to collect and transfer data into models as simple and as effective as possible and obtain solutions in the shortest time.

In this study, a methodology which utilizes multivariate statistical analysis techniques for travel estimation is presented. The two simple and convenient techniques namely Cluster Analysis and Principal Component Analysis, are used for the evaluation of available data. The traffic demand is expressed as a function of principal components which are determined independently as a small set of variables to represent total system variability. A stepwise regression analysis is carried out to derive the traffic demand‐principal component relationship. The proposed methodology is then applied to Southeastern Anatolia Regional Development Project in Turkey.     

一种新的模拟到信息转换系统

目前，模拟到信息转换系统主要通过随机矩阵进行采样的，而用硬件实现随机矩阵是繁杂的，甚至是不可能的。受到压缩传感（Compressive Sensing ，CS ）和积分点火（Integrate-and-Fire ，IF ）电路的启发，本文提出了一种无需随机矩阵且对时域编码的积分式采样还原系统。在稀疏信号足够长的条件下，可以通过参数自由控制采样频率，理论上可以无限降低，大大减少数据量，降低系统功耗。此外它易于实现，无量化误差等优点，在雷达探测、生物传感等宽带信号领域，具有很好的应用前景。     

RECONSTRUCTION OF SYNTHETIC METEOROLOGICAL SEQUENCES BY USING MARKOV TRANSITION MATRIX FOR SOLAR THERMAL SIMULATION

A Markov Transition Matrix (MTM) approach used to reconstruct the synthetic sequences of both hourly global radiation and hourly ambient temperature, which has a strong effect on the output of solar thermal systems and has not been taken into account. The result shows that the main statistical features of natural sequences, i.e., probability density function, sequential characteristics and the variance of the fluctuations, can be simulated by Markov transition-matrix obtained from recorded meteorological data. Its quality depends upon data record number in order that the synthetic sequences match long-term statistic characters of natural sequences. Comparisons have been made among different record number and the minimum number of records is sought. It is shown that the minimum data to generate hourly MTM is 12,410 data number for global radiation and 43,800 data for ambient temperature.     

Maisons résistant aux ouragans pour des families à revenus modestes

Des travaux de recherche pratiques effectués à St-Vincent dans les Caraībes ont montré comment il est possible de construire des maisons résistant aux ouragans et de coût modéré pour des families à faible revenu. Les méthodes décrites dans cet article ont suscité un intérêt général et entraîné la poursuite des travaux de recherche sur ces problèmes dans d'autres parties du monde.     

A new method for estimating initial rotor phase of self‐excited hybrid‐field synchronous motors

This paper proposes a new method for properly estimating the rotor initial phase (i.e., the position) of the newly emerging self‐excited hybrid‐field synchronous motors (SelE‐HFSMs), which have the rotor held by both a permanent magnet and a diode‐shorted held winding. The proposed method injects a spatially rotating high‐frequency voltage and detects the rotor phase directly by evaluating the norm of the associated current. The method is very simple, but has a high degree of usability. 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(3): 49–58, 2010; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.21027     

Migration measurement and modelling from poly(ethylene terephthalate) (PET) into soft drinks and fruit juices in comparison with food simulants

Poly(ethylene terephthalate) (PET) bottles are widely used for beverages. Knowledge about the migration of organic compounds from the PET bottle wall into contact media is of interest especially when post-consumer recyclates are introduced into new PET bottles. Using migration theory, the migration of a compound can be calculated if the concentration in the bottle wall is known. On the other hand, for any given specific migration limit or maximum target concentration for organic chemical compounds in the bottled foodstuffs, the maximum allowable concentrations in the polymer C _P,0 can be calculated. Since a food simulant cannot exactly simulate the real migration into the foodstuff or beverages, a worse-case simulation behaviour is the intention. However, if the migration calculation should not be too overestimative, the polymer-specific kinetic parameter for migration modelling, the so-called A _P value, should be established appropriately. One objective of the study was the kinetic determination of the specific migration behaviour of low molecular weight compounds such as solvents with relatively high diffusion rates and, therefore, with high migration potential from the PET bottle wall into food simulants in comparison with real beverages. For this purpose, model contaminants were introduced into the bottle wall during pre-form production. The volatile compounds toluene and chlorobenzene were established at concentrations from about 20–30 mg kg^?1 to 300–350 mg kg^?1. Phenyl cyclohexane was present at concentrations of 35, 262 and 782 mg kg^?1, respectively. The low volatile compounds benzophenone and methyl stearate have bottle wall concentrations of about 100 mg kg^?1 in the low spiking level up to about 1000 mg kg^?1 in the highly spiked test bottle. From these experimental data, the polymer specific parameters (A _P values) from mathematical migration modelling were derived. The experimental determined diffusing coefficients were determined, calculated and compared with literature data and an A _P′ value of 1.0 was derived thereof for non-swelling food simulants like 3% acetic acid, 10% ethanol or iso-octane. For more swelling condition, e.g. 95% ethanol as food simulant, an A _P′ value of 3.1 seems to be suitable for migration calculation. In relation to PET recycling safety aspects, maximum concentrations in the bottle wall were established for migrants/contaminants with different molecular weights, which correspond with a migration limit of 10 μg kg^?1. From the experimental data obtained using food simulants and in comparison with beverages, the most appropriate food simulant for PET packed foods with a sufficient but not too overestimative worse-case character was found to be 50% ethanol. In addition, it can be shown that mass transport from PET is generally controlled by the very low diffusion in the polymer and, as a consequence, partitioning coefficients (K _P/F values) of migrants between the polymer material and the foodstuff do not influence the migration levels significantly. An important consequence is that migration levels from PET food-contact materials are largely independent from the nature of the packed food, which on the other hand simplifies exposure estimations from PET.