On the Realization of MOS-Only Allpass Filters

The objective of this paper is to present a simple filter topology, which can be used to implement first- and second-order MOS-only allpass filters. The resulting filters realize the allpass functions without using any external passive components; hence these occupy very small chip area and are capable of operating at high frequencies. Cadence Spectre simulation and experimental results verifying the main advantages of the filters are provided.     

Low Temperature Magnetic Behavior of Ca3Co4O x Polycrystalline Material

Misfit layered Ca₃Co₄O₉ samples have been fabricated by solid-state reaction method. X-ray diffraction analysis showed that the samples have the c-axis oriented monoclinic structure. The temperature dependence of the DC magnetization of the sample fabricated was investigated in an applied field of 2000 Oe. Magnetization of the sample increased smoothly down to 20 K, then increased rapidly with decreasing temperature, suggesting a transition to the ferrimagnetic phase. M–H analysis indicated a paramagnetic behavior between 20 and 300 K and hysteretic effect below 20 K which corresponds to paramagnetic–ferrimagnetic phase transition. The ferrimagnetisms are most likely caused by interlayer coupling between the Ca₂CoO₃ and CoO₂ subsystems in unit cell.     

Durability properties of concrete with blended cements

The study of chloride‐induced corrosion started more than three decades ago, after extensive cases of damage were observed on reinforced concrete structures in coastal regions and on infrastructural objects exposed to salt action. Nowadays, the basis for sustainable concrete industry lies in these three aspects: reducing CO₂ emissions by using by‐products of other industries (slag, fly ash, silica fume) for cement production, conservation of natural resources by replacing part of the aggregate with recycled construction waste, as well as use of recycled water in concrete production, and finally, construction of durable concrete structures. Durability design procedures for reinforced concrete structures in aggressive environments are still to a large extent empirical, especially in the case of using blended cements. The type of cement has a considerable effect on the properties of concrete, especially concrete resistance to the penetration of chloride ions. The paper presents results of testing durability and deformational properties of concrete produced with quaternary‐blended cement. A clearer insight into these properties is a necessary starting point for the performance‐based design of concrete prepared with blended cements, leading to more durable and corrosion‐free concrete structures in aggressive environments.     

Parkinson’s Disease tremor classification – A comparison between Support Vector Machines and neural networks

Deep Brain Stimulation has been used in the study of and for treating Parkinson’s Disease (PD) tremor symptoms since the 1980s. In the research reported here we have carried out a comparative analysis to classify tremor onset based on intraoperative microelectrode recordings of a PD patient’s brain Local Field Potential (LFP) signals. In particular, we compared the performance of a Support Vector Machine (SVM) with two well known artificial neural network classifiers, namely a Multiple Layer Perceptron (MLP) and a Radial Basis Function Network (RBN). The results show that in this study, using specifically PD data, the SVM provided an overall better classification rate achieving an accuracy of 81% recognition.     

Factors affecting the intention to use a web-based learning system among blue-collar workers in the automotive industry

This study aims to identify, using an extended Technology-Acceptance Model (TAM), the factors affecting the decision of using a web-based learning system among blue-collar workers in the automotive industry. A structural equation-modeling approach was applied to identify the variables that significantly affect the decision of using the system. Using LISREL 8.54, data collected from 546 blue-collar workers were used to test the proposed research model. Empirical testing of the extended TAM found all paths to be significant in the hypothesized directions, that is, the results of the study strongly support the application of extended TAM in predicting the blue-collar workers’ intention to use a web-based learning system. Among the factors, social influence is a much stronger predictor of user intention compared to others. The study concludes with the implications of this study for managers and recommendations for possible future research.     

A new implementation of common matrix approach using third-order tensors for face recognition

In the classical common matrix approach (CMA), the common matrix for each individual face class is obtained using basis matrices calculated by Gram–Schmidt orthogonalization of the class covariance matrix. This common matrix represents the common or invariant properties of a given face class. The CMA idea relies on the concept of basis matrices of a face class which span the, so called, difference subspace of that class. In this paper, an alternative method to obtain the basis matrices for CMA is proposed. The basis matrices are obtained using the higher order singular value decomposition (HOSVD) of a third-order tensor constructed with face images and these basis matrices are utilized in the construction of CMA. In order to exemplify the improvements in the recognition rates, face recognition experiments are carried out via the AR face database. The original face matrices, as well as 2DPCA-, 2DSVD-, and 2DFDA-based feature matrices are applied as the input matrices for the two different implementations of CMA in the experimental studies. The results indicate that the recognition rates obtained by the proposed method are slightly higher than those obtained using the basis matrices calculated by Gram–Schmidt orthogonalization.     

微生物对混凝土的侵蚀

微生物侵蚀会导致混凝土的严重破坏,尤其导致了城市污水收集和处理系统的过早破坏,使其需要提前修复。世界范围内的研究结果表明:处于污水和下水道污泥中的混凝土会遭受由硫酸盐、酸、CO2等导致的严重破坏。评述了混凝土处于利于细菌生长和生物降解环境中时的细菌、微生物侵蚀破坏过程。此外还分析了硫酸产生的机理(硫循环)、用于污水管道系统和农用工业的混凝土的受侵蚀破坏机理以及评价混凝土抵抗微生物侵蚀的方法。     

Comparison of hemispheric asymmetry measurements for emotional recordings from controls

Four asymmetry measurements (conventional coherence function (CCF), cross wavelet correlation (CWC), phase lag index (PLI), and mean phase coherence (MPC)) have been compared to each other for the first time in order to recognize emotional states (pleasant (P), neutral (N), unpleasant (UP)) from controls in EEG sub-bands (delta (0–4 Hz), theta (4–8 Hz), alpha (8–16 Hz), beta (16–32 Hz), gamma (32–64 Hz)) mediated by affective pictures from the International Affective Picture Archiving System (IAPS). Eight emotional features, computed as hemispheric asymmetry between eight electrode pairs (Fp1 − Fp2, F7 − F8, F3 − F4, C3 − C4, T7 − T8, P7 − P8, P3 − P4, and O1 − O2), have been classified by using data mining methods. Results show that inter-hemispheric emotional functions are mostly mediated by gamma. The best classification is provided by a neural network classifier, while the best features are provided by CWC in time-scale domain due to non-stationary nature of electroencephalographic (EEG) series. The highest asymmetry levels are provided by pleasant pictures at mostly anterio-frontal (F3 − F4) and central (C3 − C4) electrode pairs in gamma. Inter-hemispheric asymmetry levels are changed by each emotional state at all lobes. In conclusion, we can state the followings: (1) Nonlinear and wavelet transform-based methods are more suitable for characterization of EEG; (2) The highest difference in hemispheric asymmetry was observed among emotional states in gamma; (3) Cortical emotional functions are not region-specific, since all lobes are effected by emotional stimuli at different levels; and (4) Pleasant stimuli can strongly mediate the brain in comparison to unpleasant and neutral stimuli.