bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and properties of silver doped SnSe2 and Ge2Sb2Te5 thin films prepared by pulsed laser deposition
Authors: Popescu M. , Velea A. , Sava F. , Lőrinczi A. , Tomescu A. , Simion C. , Matei E. , Socol G. , Mihailescu I. N. , Andonie A. , Stamatin I. 
Published: January 2010

AbstractAmorphous thin films of SnSe2 and Ge2Sb2Te5 doped by different amount of silver (0.1, 0.2, 0.5 and 1 Ag atoms per formula unit) have been prepared by pulsed laser deposition (PLD) starting from solid polycrystalline targets. The films were investigated by X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The good gas sensing properties for CO, as well as the sensitivity for CH4 and NO of the Ag doped SnSe2 films have been demonstrated in the composition SnSe2Ag0.2. The structural effect of silver introduced in Ge2Sb2Te5 matrix has been investigated. The freshly deposited thin films doped by various amount of Ag develop three phases: an amorphous one, and two crystalline phases consisting of a major fcc cubic phase of AgSbTe2 and a minor cubic phase of composition Ag2Te.
Relation of nanoscale and macroscopic properties of mixed‐phase silicon thin films
Authors: Fejfar A. , Vetushka A. , Kalusová V. , Čertík O. , Ledinský M. , Rezek B. , Stuchlík J. , Kočka J. 
Published: January 2010

AbstractScanning probe methods (SPMs) such as conductive atomic force microscopy (C‐AFM) can be used to probe the structure and local conductivity of the mixed phase silicon thin films with nanometer resolution. Effective medium approximations (EMAs) were used to relate the nanoscale properties with effective macroscopic properties for the dark conductivity measured with coplanar contacts. Comparison of the percolation threshold predicted by diffferent EMAs show partial correlation of the structure, with resistive amorphous phase coating the conductive grains. In sandwich structures (such as solar cells) the local fields may play important role: concentration of both optical and electrical internal fields to the tips of spherically capped conical microcrystalline grains. Adaptive higher‐order polynomial finite‐element methods (FEMs) were used to calculate the internal field distributions in the C‐AFM. The calculated values agree with the experimental C‐AFM, providing the first quantitative description of the relation of the nanoscale and macroscopic properties of the mixed phase Si films.
Chemical etching and surface oxidation studies of cadmium zinc telluride radiation detectors
Authors: Özsan M. E. , Sellin P. J. , Veeramani P. , Hinder S. J. , Monnier M. L. T. , Prekas G. , Lohstroh A. , Baker M. A. 
Published: January 2010

AbstractCdZnTe (CZT) is commonly used as a radiation detector material and the surface properties are important as they influence detector performance. The surface chemistry is generally controlled through chemical etching and oxidation processes. In this paper, X‐ray photoelectron spectroscopy (XPS) is employed to investigate changes in the surface composition of single‐crystal Cd0.95Zn0.05Te samples after exposure to bromine in methanol (BM) chemical etching treatments and subsequent oxidation in air or 30% H2O2. BM treatment of CZT is found to result in a graded Te‐rich surface layer which increases in thickness as a function of BM concentration. Room‐temperature air oxidation of 0.2% BM‐treated CZT follows a logarithmic rate law. BM‐treated CZT exposed to 30% H2O2 for 30 s shows a linear increase in the TeO2 oxide thickness with increasing BM concentration up to a BM concentration of 1.5%. Above 2% BM concentration, the Te enrichment in the CZT surface region has reached saturation and is effectively pure Te. Copyright © 2010 John Wiley & Sons, Ltd.
X‐ray photoelectron spectroscopy study of the interaction of ultra‐thin alumina films on NiAl alloys with NaCl solutions
Authors: Bennour Inès , Maurice Vincent , Marcus Philippe 
Published: January 2010

AbstractWe report a XPS study of the reactivity in 0.5 M NaCl aqueous solution of NiAl(100) surfaces covered by ultra‐thin aluminium oxide films grown by thermal oxidation of the alloy at 900 °C. Detailed analysis of the film thickness, the oxide stoichiometry and the alloy composition below the oxide was performed to characterize the drastic modifications induced by chloride exposure. Chloride entry in the oxide was observed by AR‐XPS that revealed the existence of two chemical states of chlorides, one associated to aluminium oxide, the other one to aluminium hydroxide. The film modifications were initiated in the inner part and characterized by the formation of chloride‐containing hydroxide species. The growth of these species spread later to the entire film, accompanied by a marked thickening of the modified alumina layer by selective oxidation of the alloy. Longer immersion times (>20 h) led to the formation of mixed nickel–aluminium chloride‐containing hydroxide species, indicating the loss of corrosion protection. Copyright © 2010 John Wiley & Sons, Ltd.
Intelligent cognition‐based systems approach to multiple‐criteria computerized essay assessment
Authors: Cheng Shu‐Ling 
Published: January 2010

AbstractWith the advance of computational techniques, computerized assessment becomes increasingly popular due to the advantages of consistency, efficiency and labour‐saving. In computerized assessment, it evaluates the subject's performance based on the experts' assessment criteria and also criteria preferences, thus indicating an effort to implement expert assessment policy. The key element of developing the computerized assessment system is to measure the complexity of an expert's cognitive structures containing assessment criteria and criteria preferences. To achieve this goal, we present an intelligent cognition‐based systems approach which includes three integrated parts to build the computerized assessment model. It first utilizes text‐mining techniques to automatically around important meaning themes that frame as assessment criteria. Human experts' criteria preferences are then derived from the pre‐assessed essays by applying a multiple‐criteria decision analysis. Meanwhile, the optimal parameter set for the assessment system is determined using the genetic algorithm. To demonstrate its effectiveness, the essays of university students majoring in information management are empirically evaluated by the proposed method. The results show that the proposed method can not only effectively model expert cognitive structure but also report high classification accuracy under different assessment settings. Copyright © 2010 John Wiley & Sons, Ltd.
Verification support for ARINC‐653‐based avionics software
Authors: de la Cámara Pedro , Castro J. Raúl , Gallardo María del Mar , Merino Pedro 
Published: January 2010

AbstractSoftware model checking consists in applying the most powerful results in formal verification research to programming languages such as
C. One general technique to implement this approach is producing a reduced model of the software in order to employ existing and efficient tools, such as
SPIN. This paper focusses on the application of this approach to the avionics software constructed on top of the Application Executive Software (APEX) Interface, which is widely employed by manufacturers in the avionics industry. It presents a method to automatically extract PROMELA models from the C source code. In order to close the extracted model during verification, we built a reusable APEX‐specific environment. This APEX environment models the execution engine (i.e. an APEX compliant real‐time operating system) that implements APEX services. In particular, it explains how to deal with aspects such as real‐time and APEX scheduling. Time is modelled in such a way that the we save time and memory by avoiding the analysis of irrelevant steps. This model of time and the construction of a deterministic scheduler guarantees the scalability of our approach. The paper also presents a tool that can verify realistic applications, and that has been used as a novel testing method to ensure the correctness of our APEX environment. This testing method uses SPIN to execute official APEX test cases. Copyright © 2010 John Wiley & Sons, Ltd.
Validation of volume measurements for fetal echocardiography using four‐dimensional ultrasound imaging and spatiotemporal image correlation
Authors: Uittenbogaard L. B. , Haak M. C. , Peters R. J. H. , van Couwelaar G. M. , Van Vugt J. M. G. 
Published: January 2010

AbstractObjectivesTo assess the accuracy and reliability of four‐dimensional (4D) ultrasound imaging using spatiotemporal image correlation (STIC) employing three different techniques to measure volumes in vitro.MethodsCustomized miniature balloons attached to a pump system were used to mimic fetal cardiac chambers. After the balloon model had been immersed in a bath filled with viscous gel, 4D datasets were acquired and three methods were used for volume analysis: three dimensional (3D) slice method, Virtual Organ Computer‐aided AnaLysis (VOCAL™) and VOCAL combined with inversion mode. Accuracy and measurement error were measured as the difference between the volume measurements and the actual volumes. Intraobserver reliability was assessed by computing coefficients of variation (CV) and intraclass correlation (ICC).ResultsMeasurement of 76 different volumes, ranging from 0.30 to 4.95 mL, resulted in a total of 912 measurements. The 3D slice method had a mean error of −3.3%, the inversion method underestimated the volumes with a mean error of −6.1%, and VOCAL had a mean error of −2.9%. The 3D slice method had the best agreement (95% limits of agreement (LOA), −11.2 to 4.7%), followed by VOCAL (95% LOA, −14.1 to 8.3%); the inversion mode demonstrated the worst agreement (95% LOA, −21.4 to 9.2%). All three methods were reliable with CV < 10% and ICC > 0.95.Conclusions4D ultrasonography with STIC is a feasible and accurate method for calculating volumes of 0.30 mL upwards. In an in‐vitro model the 3D slice method proved accurate, was the least time consuming, had the best reliability and had the smallest LOA. This method may prove useful when applied to in‐vivo investigations. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Quantitative three‐dimensional power Doppler angiography: a flow‐free phantom experiment to evaluate the relationship between color gain, depth and signal artifact
Authors: Martins W. P. , Raine‐Fenning N. J. , Ferriani R. A. , Nastri C. O. 
Published: January 2010

AbstractObjectivesTo evaluate the presence of false flow three‐dimensional (3D) power Doppler signals in ‘flow‐free’ models.Methods3D power Doppler datasets were acquired from three different flow‐free phantoms (muscle, air and water) with two different transducers and Virtual Organ Computer‐aided AnaLysis was used to generate a sphere that was serially applied through the 3D dataset. The vascularization flow index was used to compare artifactual signals at different depths (from 0 to 6 cm) within the different phantoms and at different gain and pulse repetition frequency (PRF) settings.ResultsArtifactual Doppler signals were seen in all phantoms despite these being flow‐free. The pattern was very similar and the degree of artifact appeared to be dependent on the gain and distance from the transducer. False signals were more evident in the far field and increased as the gain was increased, with false signals first appearing with a gain of 1 dB in the air and muscle phantoms. False signals were seen at a lower gain with the water phantom (−15 dB) and these were associated with vertical lines of Doppler artifact that were related to PRF, and disappeared when reflections were attenuated.ConclusionsArtifactual Doppler signals are seen in flow‐free phantoms and are related to the gain settings and the distance from the transducer. In the in‐vivo situation, the lowest gain settings that allow the detection of blood flow and adequate definition of vessel architecture should be used, which invariably means using a setting near or below the middle of the range available. Additionally, observers should be aware of vertical lines when evaluating cystic or liquid‐containing structures. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Three‐dimensional ultrasound of the pelvic floor 2 days after first delivery: influence of constitutional and obstetric factors
Authors: Falkert A. , Endress E. , Weigl M. , Seelbach‐Göbel B. 
Published: January 2010

AbstractObjectivesMorphological changes of the pelvic floor during pregnancy and delivery can be visualized by three‐dimensional (3D) perineal ultrasound. The aim of this study was to compare biometric measurements of the levator ani muscle according to maternal constitutional factors, delivery mode and size of the baby immediately after the first delivery.MethodsIn this prospective observational study, 130 primiparae were recruited (all of them Caucasians with singleton pregnancy and cephalic presentation). A 3D perineal ultrasound scan was performed on the second day after delivery with standardized settings. Volumes were obtained at rest and on Valsalva maneuver, and biometric measurements of the levator hiatus were determined in the axial plane. Different obstetric and constitutional parameters were obtained from our clinical files.ResultsAll biometric measurements of the levator hiatus were significantly greater in the vaginal delivery group than in the Cesarean section group (P < 0.001), whereas subgroup analysis within the vaginal (spontaneous vs. operative vaginal) and Cesarean (primary vs. secondary) delivery groups did not show statistically significant differences. There was no demonstrable influence of maternal constitutional factors (age, body mass index (BMI)) or different obstetric parameters (length of second stage of labor, episiotomy, maternal injuries) on levator hiatus size postpartum, even in subgroups that delivered vaginally. Women with de novo postpartum stress incontinence showed a significantly higher mean levator hiatus transverse diameter and larger hiatal area on Valsalva maneuver (P < 0.05). There was also a positive but very weak correlation between the newborn's head circumference and hiatal dimensions at Valsalva maneuver (P < 0.05).ConclusionsPelvic floor imaging by 3D ultrasound is easily accessible even on the first days after delivery and can provide useful information on morphological changes of the levator ani muscle. In our study, women with vaginal or operative vaginal delivery had a significantly larger hiatal area and transverse diameter than women who delivered by Cesarean section. Maternal constitutional factors (BMI, age) and duration of second stage of labor had no influence on the biometric measurements of hiatal area, whereas weight and head circumference of the baby showed a positive correlation with area of the levator hiatus. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Jointly multi‐user detection and channel estimation with genetic algorithm
Authors: Ciriaco Fernando , Abrão Taufik , de Toledo Antonio Fischer , Jeszensky Paul Jean E. 
Published: January 2010

AbstractThis work aims at proposing the use of the evolutionary computation methodology in order to jointly solve the multi‐user channel estimation (MuChE) and detection problems at its maximum‐likelihood, both related to the direct sequence code division multiple access (DS/CDMA). The effectiveness of the proposed heuristic approach is proven by comparing performance and complexity merit figures with that obtained by traditional methods found in literature. Simulation results considering genetic algorithm (GA) applied to multipath, DS/CDMA and MuChE and multi‐user detection (MuD) show that the proposed genetic algorithm multi‐user channel estimation (GAMuChE) yields a normalized mean square error estimation (nMSE) inferior to 11%, under slowly varying multipath fading channels, large range of Doppler frequencies and medium system load, it exhibits lower complexity when compared to both maximum likelihood multi‐user channel estimation (MLMuChE) and gradient descent method (GrdDsc). A near‐optimum multi‐user detector (MuD) based on the genetic algorithm (GAMuD), also proposed in this work, provides a significant reduction in the computational complexity when compared to the optimum multi‐user detector (OMuD). In addition, the complexity of the GAMuChE and GAMuD algorithms were (jointly) analyzed in terms of number of operations necessary to reach the convergence, and compared to other jointly MuChE and MuD strategies. The joint GAMuChE–GAMuD scheme can be regarded as a promising alternative for implementing third‐generation (3G) and fourth‐generation (4G) wireless systems in the near future. Copyright © 2010 John Wiley & Sons, Ltd.
Synchronization challenges in media access coordination for vehicularad hocnetworks
Authors: Blum Jeremy J. , Natarajan Rajesh , Eskandarian Azim 
Published: January 2010

AbstractVehicularad hocnetworks (VANETs) can support a wide range of future cooperative safety and efficiency applications. However, the node density and high demand for wireless media in these networks can lead to theTimeslot Boundary Synchronization Problem, in which increased transmission collisions occur due to back‐off timer synchronization. This paper proposes an enhancement to the wireless access in vehicular environments (WAVE) communications architecture to address this problem, called RAndom Propagation Initiation Delay for the Distributed Coordination Function (RAPID DCF). The effectiveness of RAPID DCF is evaluated through simulations of both single‐hop and multi‐hop emergency messages. In these simulations, RAPID DCF was able to improve message delivery rates by as much as 35% and reduce multi‐hop message latency by as much as 18%. Copyright © 2010 John Wiley & Sons, Ltd.
A Stackelberg game for resource allocation in multiuser cooperative transmission networks
Authors: Cong Li , Zhao Liqiang , Yang Kun , Zhang Hailin , Zhang Guopeng 
Published: January 2010

AbstractIn this paper, we consider the problem of stimulating cooperation and resource allocation in cooperative transmission networks. We formulate this problem as a sellers' market competition where a relay is willing to share its resource with multiple users. We use a Stackelberg game to jointly consider the benefits of the relay and the users. Firstly, the relay determines the price of relaying according to the user demand. Secondly, the users purchase the optimal amount of resources to maximize their utilities. Although the Nash equilibrium, i.e., the solution of the game, can be obtained in a centralized manner, we develop a distributed algorithm to search the Nash equilibrium, which is more applicable in practical systems. Also, the convergence conditions of the algorithm are analyzed. Simulation results show, by using the distributed algorithm, the relay and the users could determine what price should ask for and how much bandwidth should buy, respectively. Copyright © 2010 John Wiley & Sons, Ltd.
Power control for delay constrained multi‐channel communications using outdated CSI
Authors: Li Xiaochen , Cao Fengming , Dong Xihua , Wu Dapeng 
Published: January 2010

AbstractIn this paper, we study the power allocation scheme for a single user, multi‐channel system, e.g., orthogonal frequency‐division multiplexing (OFDM) systems, under time‐variant wireless fading channels. We assume the receiver feeds back perfectly estimated channel state information (CSI) to the transmitter after a processing delay. The objective of the power allocation is to maximize throughput subject to quality‐of‐service (QoS) constraint. The QoS measure of our consideration is a triplet of data rate, delay, and delay bound violation probability. A two‐step sub‐optimal power allocation scheme is proposed to address the impact of outdated CSI. In the first step, the total transmission power that can be used within one block is determined according to the summation of the channel gains of all the channels. In the second step, the total transmission power is allocated among all the channels. The proposed power control scheme is less sensitive to the feedback delay. Compared to the optimal power allocation scheme designed for the perfect CSI scenario, it has lower computational complexity while achieving comparable capacity. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient multiplicity calculation for algebraic soft‐decision decoding of Reed—Solomon codes
Authors: An Jianping , Jiang Tao , Li Xiangming , Li Anxin , Kayama Hidetoshi 
Published: January 2010

AbstractSoft‐decision decoding of Reed—Solomon (RS) codes consists of three key steps: multiplicity calculation, bivariate interpolation, and factorization. In this work, we investigate the first step, with the aim of reducing the complexity of multiplicity calculation. It is observed that the objective value of multiplicity calculation in Koetter and Vardy's (KV) algorithm can be expressed as an increasing function of independent parameter. Based on this fact, we propose to use bisection or golden section methods in multiplicity calculation. Simulation study demonstrates that our proposed approach can significantly reduce the computational complexity of RS codes decoding. Copyright © 2010 John Wiley & Sons, Ltd.
Bandwidth‐ efficient space–time coded cooperation for resource‐constrained networks
Authors: Kim Jee‐Hoon , Vasilakos Athanasios V. , Song Hyoung‐Kyu 
Published: January 2010

AbstractIn cooperative transmission, cooperating nodes must hear the source messages first and forward it to the destination node with decodable composition of symbols. This restriction is one of big questions in cooperative networks since it decreases overall bandwidth‐efficiency. In this paper, we propose a scheme which alleviates it through novel use of dual carrier modulation (DCM) and an adequately designed distributed space–time block code (DSTBC). The proposed scheme achieves comparable error performance to the conventional one while providing 20% higher transmission rate. The performance is always guaranteed by the signal‐to‐noise ratio (SNR) based adaptive cooperation algorithm. Copyright © 2010 John Wiley & Sons, Ltd.
Neuronopathic Gaucher disease: demographic and clinical features of 131 patients enrolled in the International Collaborative Gaucher Group Neurological Outcomes Subregistry
Authors: Tylki‐Szymańska Anna , Vellodi Ashok , El‐Beshlawy Amal , Cole J. Alexander , Kolodny Edwin 
Published: January 2010

AbstractObjectiveTo describe demographic, genetic, and clinical characteristics of patients with neuronopathic Gaucher disease (NGD).MethodsAll patients enrolled in the Neurological Outcomes Subregistry of the International Collaborative Gaucher Group (ICGG) Gaucher Registry as of June 2007 were identified.ResultsThe study cohort comprised 131 patients from 17 countries who were enrolled in the Neurological Outcomes Subregistry. The onset of neurological manifestations had occurred before 2 years of age in 47% (61 out of 131 patients), 2 years of age or older in 41% (54 out of 131), and could not be ascertained in the remaining 12% (16 out of 131). The most common manifestations were inability to look to the extreme up or down (45%, 55 out of 123), abnormally slow object tracking (43%, 53 out of 123), convergent squint (36%, 44 out of 121), and ataxia (15 to 20%, 18–27 out of 117). Seizures were reported in 19 out of 122 patients (16%), and myoclonic seizures were reported in 3 out of 121 patients (2%). The most common genotypes were L444P/L444P (76 out of 108, 70%), L444P/D409H (9 out of 108, 8%), D409H/D409H (8 out of 108, 7%), and L444P/rare allele (6 out of 108, 6%); full sequencing was not performed in all patients.ConclusionsNeurological manifestations of GD often begin to appear before the age of 2 years. The most common neurological signs and manifestations are brainstem abnormalities and fine motor dysfunction. The most common genotype is L444P/L444P.