bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast seismic modeling and reverse time migration on a graphics processing unit cluster
Authors: Abdelkhalek Rached , Calandra Henri , Coulaud Olivier , Latu Guillaume , Roman Jean 
Published: October 2011

SUMMARYWe designed a fast parallel simulator that solves the acoustic wave equation on a graphics processing unit (GPU) cluster. Solving the acoustic wave equation in an oil exploration industrial context aims at speeding up seismic modeling and reverse time migration (RTM). We considered a finite difference approach on a regular mesh, in both two‐dimensional and three‐dimensional cases. The acoustic wave equation is solved in a constant density or a variable density domain. All the computations were carried out in single precision (both in the CPU reference implementation and in the GPU implementation), because double precision was not required in our context. We used Compute Unified Device Architecture to take advantage of the GPU computational power. We studied different implementations and their impact on the application performance. The described application handles all the steps of seismic modeling and RTM and is used to solve real‐world problems in an industrial production context. We obtained a speedup of 16 for RTM and up to 43 for the modeling application over a sequential code running on general‐purpose CPUs. A CPU rack versus a GPU rack comparison was described and showed a 4.3 speedup. Copyright © 2011 John Wiley & Sons, Ltd.
Electronic Structures and Thermochemical Properties of the Small Silicon‐Doped Boron Clusters BnSi (n=1–7) and Their Anions
Authors: Tai Truong Ba , Kadłubański Paweł , Roszak Szczepan , Majumdar Devashis , Leszczynski Jerzy , Nguyen Minh Tho 
Published: October 2011

AbstractWe perform a systematic investigation on small silicon‐doped boron clusters BnSi (n=1–7) in both neutral and anionic states using density functional (DFT) and coupled‐cluster (CCSD(T)) theories. The global minima of these BnSi0/− clusters are characterized together with their growth mechanisms. The planar structures are dominant for small BnSi clusters with n≤5. The B6Si molecule represents a geometrical transition with a quasi‐planar geometry, and the first 3D global minimum is found for the B7Si cluster. The small neutral BnSi clusters can be formed by substituting the single boron atom of Bn+1 by silicon. The Si atom prefers the external position of the skeleton and tends to form bonds with its two neighboring B atoms. The larger B7Si cluster is constructed by doping Si‐atoms on the symmetry axis of the Bn host, which leads to the bonding of the silicon to the ring boron atoms through a number of hyper‐coordination. Calculations of the thermochemical properties of BnSi0/− clusters, such as binding energies (BE), heats of formation at 0 K (ΔHf0) and 298 K (ΔHf[298]), adiabatic (ADE) and vertical (VDE) detachment energies, and dissociation energies (De), are performed using the high accuracy G4 and complete basis‐set extrapolation (CCSD(T)/CBS) approaches. The differences of heats of formation (at 0 K) between the G4 and CBS approaches for the BnSi clusters vary in the range of 0.0–4.6 kcal mol−1. The largest difference between two approaches for ADE values is 0.15 eV. Our theoretical predictions also indicate that the species B2Si, B4Si, B3Si− and B7Si− are systems with enhanced stability, exhibiting each a double (σ and π) aromaticity. B5Si− and B6Si are doubly antiaromatic (σ and π) with lower stability.
Implementation of parallel zero‐voltage switching converter with series‐connected transformers
Authors: Lin Bor‐Ren , Cheng Chih‐Yuan 
Published: October 2011

SUMMARYThis paper presents a parallel zero‐voltage switching (ZVS) DC–DC converter with series‐connected transformers. In order to increase output power, two transformers connected in series are used in the proposed converter. Two buck‐type converters connected in parallel have the same switching devices. The primary windings of series‐connected transformers can achieve the balanced secondary winding currents. The current doubler rectifiers with ripple current cancellation are connected in parallel at the output side to reduce the current stress of the secondary winding. Thus, the current ripple on the output capacitor is reduced, and the size of the output choke and output capacitor are reduced. Only two switches are used in the proposed circuit instead of four switches in the conventional parallel ZVS converter to achieve ZVS and output current sharing. Therefore, the proposed converter has less power switches. The ZVS turn‐on is implemented during the commutation stage of two complementary switches such that the switching losses and thermal stresses on the semiconductors are reduced. Experimental results for a 528‐W (48 V/11 A) prototype are presented to prove the theoretical analysis and circuit performance. Copyright © 2011 John Wiley & Sons, Ltd.
Switched‐capacitor‐voltage‐multiplier boost DC–AC inverter with adaptive stages
Authors: Chang Yuen‐Haw , Wu Ming‐Zong 
Published: October 2011

SUMMARYA multistage switched‐capacitor‐voltage‐multiplier inverter (SCVMI) is proposed with a variable‐conversion‐ratio phase generator and a sinusoidal pulse‐width‐modulation controller for boost DC–AC conversion and high‐efficiency regulation. Its power unit contains: SCVM booster and H‐bridge. The SCVM booster includes two mc‐stage switched‐capacitor cells and two nc‐stage switched‐capacitor cells in the interleaving operation to realize DC–DC boost gain of mc × nc at most. Here, the variable‐conversion‐ratio phase generator is suggested and adopted to change the running stage number and topological path for a suitable gain level of m × n (m = 1, 2, ⋯,mc, n = 1, 2, ⋯,nc) to improve efficiency, especially for the lower AC output. The H‐bridge is employed for DC–AC conversion, where four switches are controlled by sinusoidal pulse‐width‐modulation not only for full‐wave output but also for output regulation as well as robustness to source/loading variation. Some theoretical analysis and design include: SCVMI model, steady‐state/dynamic analysis, conversion ratio, power efficiency, stability, capacitance selection, output filter, and control design. Finally, the closed‐loop SCVMI is simulated, and the hardware circuit is implemented and tested. All the results are illustrated to show the efficacy of this scheme. Copyright © 2011 John Wiley & Sons, Ltd.
Low‐power, low‐area preamplifier for ultra high‐speed multi‐channel optical communication system
Authors: Wang Xiaoxia , Wang Zhigong 
Published: October 2011

SUMMARYA novel circuit technique was applied to the design of a preamplifier for ultra high‐speed short‐distance parallel optical communication system in standard 180‐nm CMOS technology. This circuit is featured by low power, low area as well as high gain bandwidth product, and suited for applications in low‐cost process. The restraint on voltage headroom as bottleneck in traditionally adopted regulated cascode configuration has been fundamentally analyzed and lifted by feed‐forward common gate stage to achieve high gain bandwidth product under limited fT and strict power restriction. Complex poles were carefully assigned to further attain bandwidth extension without sacrifice on power, noise, and chip area. No additional peaking techniques and subsequent gain‐boosting stages are adopted, which makes the design simple and favorable in low‐cost high‐density multi‐channel optical communication system. The preamplifier provides a trans‐impedance gain of up to 52 dBΩ and a 3‐dB bandwidth of 8.4 GHz. Operating under a 1.8‐V supply, the power dissipation is 8 mW, and the chip area is only 0.075×0.08 mm. The measured average input‐referred noise–current spectral density is . Copyright © 2011 John Wiley & Sons, Ltd.
Structural characterization of classical and memristive circuits with purely imaginary eigenvalues
Authors: Riaza Ricardo , Tischendorf Caren 
Published: October 2011

SUMMARYThe hyperbolicity problem in circuit theory concerns the existence of purely imaginary eigenvalues in the linearization of the time‐domain description of the circuit dynamics. In this paper, we characterize the circuit configurations that, in a strictly passive setting, yield purely imaginary eigenvalues for all values of the capacitances and inductances. Our framework is based on branch‐oriented, semistate (differential‐algebraic) circuit models that capture explicitly the circuit topology, and use several notions and results from digraph theory. So‐called P‐structures arising in the analysis turn out to be the key element supporting our results. The analysis is shown to hold not only for classical (RLC) circuits but also for nonlinear circuits including memristors and other mem‐devices. Copyright © 2011 John Wiley & Sons, Ltd.
Non‐idealities in linear CDR phase detectors
Authors: Cao Jun , Huang Sui , Green Michael M. 
Published: October 2011

SUMMARYThe effects of circuit non‐idealities in a “Hogge”‐type phase detector are examined. Using a behavioral model for each circuit block, it is shown that various circuit non‐idealities introduce static phase offset in the phase detector, reduce the monotonic range of its transfer characteristics and eventually degrade the capture range and jitter tolerance of the clock and data recovery (CDR) loop. Lower bounds on the bandwidths of the various blocks in the CDR are also established in order to avoid variations of the transfer characteristics. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation and comparison of GHz‐range LC oscillators using time‐varying root‐locus
Authors: Broussev Svetozar S. , Tchamov Nikolay T. 
Published: October 2011

SUMMARYThis paper presents a comprehensive comparison between complementary metal‐oxide‐semiconductor (CMOS) LC‐oscillator topologies often used in GHz‐range transceivers. The comparison utilizes the time‐varying root‐locus (TVRL) method to add new insights into the operation of different oscillators. The paper focuses on the treatment of the TVRL trajectories obtained for different oscillators and establishes links between the trajectories and physical phenomena in oscillators. The evaluation of the root trajectories shows the advantages of the TVRL method for comparing oscillator topologies, which is also extended towards the analysis of voltage‐controlled oscillators. The necessary circuit simplifications required in closed‐form root‐locus analysis are avoided by the TVRL, which allows precise oscillator comparison and reveals details on the topology specifics. The derived conclusions have been verified by the Cadence Spectre‐RF simulator on 130‐nm CMOS process. Copyright © 2011 John Wiley & Sons, Ltd.
1.5 V square‐root domain universal biquad filters
Authors: Laoudias C. , Psychalinos C. , Stoumpou E. 
Published: October 2011

ABSTRACTSquare‐root domain universal biquad topologies are introduced in this paper. One of them is single input multiple output, while the other one is multiple input single output biquad. Important benefits offered by the proposed topologies are the electronic adjustment of the resonant frequency and the capability for operating in a low‐voltage environment; also, the resonant frequency could be adjusted without disturbing the Q factor and vice‐versa. Simulation results using the Spectre simulator of the Analog Design Environment of Cadence software validate the correct operation of the proposed topologies and provide important performance characteristics. Copyright © 2011 John Wiley & Sons, Ltd.
Dynamic OSR dithered sigma–delta modulation in solid state light dimming
Authors: Orcioni Simone , d'Aparo Rocco , Lobascio Armando , Conti Massimo 
Published: October 2011

SUMMARYPulse width modulation (PWM) is the most common way to control switching regulation and digital dimming. This paper presents a way to implement digital dimming by means of a dithered sigma–delta modulator with dynamic oversampling ratio. The system has been modeled in SystemC‐WMS and implemented in a board using a commercial microcontroller. Simulation results show conducted electromagnetic interference reduction compared to PWM and flickering reduction with respect to classic sigma‐delta modulation. Copyright © 2011 John Wiley & Sons, Ltd.
Optimization‐based method for shunt hybrid filter compensation in non‐stiff systems
Authors: Ramos‐Carranza Hugo , Medina Aurelio 
Published: October 2011

SUMMARYIn this contribution, a steady‐state approach for determining the optimal size and control of a shunt hybrid filter (SHF), to control harmonic current mitigation and to provide reactive power compensation, is proposed. The SHF topology is formed by a shunt active power filter (APF) and a shunt capacitor. The APF current injections are determined from the solution of a nonlinear programming problem formulated to meet permissible operation limits, with an optimal APF size. The formulation and control theory for the SHF is developed in the abc reference frame. An important practical aspect such as the application of SHF compensation in non‐stiff systems is included in the analysis and solution of the nonlinear programming problem, as well as in the current control technique, maintaining stringent performance requirements on the tracking of the filtering currents, by allowing the use of the shunt capacitor also as a filter for draining the ripple current inherent to the APF injection currents. Results obtained with matlab/Simulink (MathWorks, Inc., Natick, MA, USA) show that the proposed theory and the control of the optimal SHF compensation constitute an effective system to compensate reactive power and to control harmonic distortion under selected/permissible limits with an optimal APF injection current reducing the APF size. Copyright © 2011 John Wiley & Sons, Ltd.
A 12‐bit multi‐channel dual‐mode successive approximation ADC for power management bus (Pmbus) devices
Authors: Chiang Cheng‐Ta , Chang Wei‐Hsu 
Published: October 2011

SUMMARYIn this paper, a 12‐bit multi‐channel dual‐mode successive approximation ADC for PMBus devices is newly proposed. The proposed data converter is attractive because all the requirements of PMBus devices, which are high resolution, low‐cost, dual‐mode, and multi‐channel, are successfully matched. In measurement results, all the functions and performance of the proposed data converter are successfully verified and confirmed to be applied on PMBus devices. The area of this chip is 1.64 × 1.56 mm2, and the measured power consumption including digital output buffers is 1.683 mW. The proposed 12‐bit multi‐channel dual‐mode successive approximation ADC is suitable for power monitoring systems, such as PMBus devices. Copyright © 2011 John Wiley & Sons, Ltd.
Dynamic mixed serial–parallel content addressable memory (DMSP CAM)
Authors: Kang Mingu , Kim Jisu , Yang Young Hwi , Jung Seong‐Ook 
Published: October 2011

SUMMARYA novel dynamic mixed serial–parallel content addressable memory (DMSP CAM) is proposed to achieve both low‐power consumption and high performance. The replica circuits provide optimal timings to enable and disable the matchline charge transistor, which maximizes performance and minimizes leakage current, respectively. The DMSP CAM does not suffer from charge sharing in the serial stage and achieves high performance by removing the predischarge or precharge operation of the matchline before every comparison. To guarantee the robustness of the proposed scheme, a statistical design methodology is also applied. Using the 45‐nm technology, the DMSP CAM achieves both energy saving and performance improvement, and thus over 53% energy‐delay product reduction compared with the other serial–parallel mixed CAMs. Copyright © 2011 John Wiley & Sons, Ltd.
Analysis of implicit HHT‐α integration algorithm for real‐time hybrid simulation
Authors: Chen Cheng , Ricles James M. 
Published: October 2011

SUMMARYReal‐time hybrid simulation is a viable experiment technique to evaluate the performance of structures equipped with rate‐dependent seismic devices when subject to dynamic loading. The integration algorithm used to solve the equations of motion has to be stable and accurate to achieve a successful real‐time hybrid simulation. The implicit HHT α‐algorithm is a popular integration algorithm for conducting structural dynamic time history analysis because of its desirable properties of unconditional stability for linear elastic structures and controllable numerical damping for high frequencies. The implicit form of the algorithm, however, requires iterations for nonlinear structures, which is undesirable for real‐time hybrid simulation. Consequently, the HHT α‐algorithm has been implemented for real‐time hybrid simulation using a fixed number of substep iterations. The resulting HHT α‐algorithm with a fixed number of substep iterations is believed to be unconditionally stable for linear elastic structures, but research on its stability and accuracy for nonlinear structures is quite limited. In this paper, a discrete transfer function approach is utilized to analyze the HHT α‐algorithm with a fixed number of substep iterations. The algorithm is shown to be unconditionally stable for linear elastic structures, but only conditionally stable for nonlinear softening or hardening structures. The equivalent damping of the algorithm is shown to be almost the same as that of the original HHT α‐algorithm, while the period elongation varies depending on the structural nonlinearity and the size of the integration time‐step. A modified form of the algorithm is proposed to improve its stability for use in nonlinear structures. The stability of the modified algorithm is demonstrated to be enhanced and have an accuracy that is comparable to that of the existing HHT α‐algorithm with a fixed number of substep iterations. Both numerical and real‐time hybrid simulations are conducted to verify the modified algorithm. The experimental results demonstrate the effectiveness of the modified algorithm for real‐time testing. Copyright © 2011 John Wiley & Sons, Ltd.
Depression and frailty in later life: a synthetic review
Authors: Mezuk Briana , Edwards Lauren , Lohman Matt , Choi Moon , Lapane Kate 
Published: October 2011

BackgroundMany of the symptoms, consequences, and risk factors for frailty are shared with late‐life depression. However, thus far, few studies have addressed the conceptual and empirical interrelationships between these conditions. This review synthesizes existing studies that examined depression and frailty among older adults and provides suggestions for future research.MethodsA search was conducted using PubMed for publications through 2010. Reviewers assessed the eligibility of each report and abstracted information on study design, sample characteristics, and key findings, including how depression and frailty were conceptualized and treated in the analysis.ResultsOf 133 abstracted articles, 39 full‐text publications met inclusion criteria. Overall, both cross‐sectional (n = 16) and cohort studies (n = 23) indicate that frailty, its components, and functional impairment are risk factors for depression. Although cross‐sectional studies indicate a positive association between depression and frailty, findings from cohort studies are less consistent. The majority of studies included only women and non‐Hispanic Whites. None used diagnostic measures of depression or considered antidepressant use in the design or analysis of the studies.ConclusionsA number of empirical studies support for a bidirectional association between depression and frailty in later life. Extant studies have not adequately examined this relationship among men or racial/ethnic minorities, nor has the potential role of antidepressant medications been explored. An interdisciplinary approach to the study of geriatric syndromes such as late‐life depression and frailty may promote cross‐fertilization of ideas leading to novel conceptualization of intervention strategies to promote health and functioning in later life. Copyright © 2011 John Wiley & Sons, Ltd.
PRODUCTIVITY COSTS REVISITED: TOWARD A NEW US POLICY
Authors: Nyman John A. 
Published: October 2011

ABSTRACTIn 1996, the Washington Panel recommended that the productivity costs that are not directly related to obtaining care be captured in the quality‐of‐life weights used to construct the quality‐adjusted life years (QALYs) in American cost–utility analyses. This paper revisits the original justification of the Panel and the critiques that appeared in the literature at the time. It then analyzes how productivity costs would be viewed from a cost–benefit analysis perspective to identify their welfare implications and then translates these implications into what they mean for how to express productivity costs in a cost–utility analysis. Next, three consistency issues are identified: (i) consistency between the welfare implications and the health status questionnaires used to construct the QALYs; (ii) consistency between the productivity costs from morbidity and mortality; and (iii) consistency between the measurement of productivity costs and the societal perspective. Finally, after reviewing the productivity costs policies of other countries, the paper makes a modest proposal for a new US policy. Copyright © 2011 John Wiley & Sons, Ltd.
An Efficient Synthesis of Mono and Bis‐1,2,3‐triazole AZT Derivatives via Copper(I)‐catalyzed Cycloaddition
Authors: Yuan Jin‐Wei , Qu Ling‐Bo , Chen Xiao‐Lan , Qu Zhi‐Bo , Liu Xiang‐Qian , Ke Dian‐Dian 
Published: October 2011

AbstractAn efficient synthesis of novel mono and bis‐1,2,3‐triazoles 3′‐azido‐2′‐deoxythymidine (AZT) derivatives via copper(I)‐catalyzed 1,3‐dipolar cycloaddition reaction is described. Starting from AZT and terminal alkyne derivatives, mono and bis‐1,2,3‐triazole AZT derivatives are regioselectively obtained in good yields under mild conditions using CuSO4·5H2O and sodium ascorbate as a catalyst system, and t‐BuOH/H2O (1:1, v/v) as a co‐solvent. The structures of these compounds were elucidated by IR, HR MS and NMR.
Synthesis and Biological Activity of a Series of Novel N‐Substituted β‐Lactams Derived from Natural Gallic Acid
Authors: Cao Xiu‐Fang , Wang Yun‐Shen , Li Shao‐Wei , Chena Chang‐Shu , Ke Shao‐Yong 
Published: October 2011

AbstractA series of novel β‐lactams derived from natural gallic acid were conveniently synthesized via classical Staudinger ketene‐imine cycloaddition reaction. Their structures were confirmed by satisfactory analytical and spectroscopic methods. The preliminary bioassay showed that some of the target compounds exhibited obvious insecticidal activity against Heliothis armigera at the dosage of 0.2 mg/mL.
Zinc(II) and Cadmium(II) Metal Complexes with Bis(tetrazole) Ligands: Synthesis and Crystal Structures
Authors: Bai Mei , Zhang Jian‐Bin , Cao Ling‐Hua , Li Yan‐Ping , Wang Duo‐Zhi 
Published: October 2011

AbstractTwo new metal complexes [Zn(L1)]n (1) and [Cd3(L2)2Cl2(H2O)6]n (2) (H2L1 = 1,5‐bis(tetrazol‐5‐yl)‐3‐oxapentane, H2L2 = bis(tetrazol‐5‐yl)methane) have been synthesized and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction analysis. Complex 1 was a 2‐D sheet constructed by L1 and Zn(II) center, further assembled to form a three‐dimensional (3‐D) supramolecular networks through weak hydrogen‐bonding interactions. In the complex 2, there were two unequivalent Cd(II) centers, and some of ligands L2 adopted chelate coordination mode, and others adopted bridge coordination mode linking the Cd1 center and simultaneously bridging the Cd2 center, the Cl‐ anions adopted μ2 bridging mode, ligands L2 and the Cl‐ anions linked the Cd(II) centers to form a 3‐D supramolecular networks.
Hypervalent Iodine(III) Reagent Mediated Synthesis of 2‐Methylbenzofuran Derivatives by Pummerer‐type Reaction in Ionic Liquid
Authors: Chung Chi‐Lin , Han Chein‐Hwa , Wang Huey‐Min , Hou Rei‐Sheu , Chen Ling‐Ching 
Published: October 2011

AbstractAn efficient route for the synthesis of 2‐methylbenzofuran derivatives utilizing hypervalent iodine(III) reagent and a‐(methylthio)acetone via Pummerer‐type reaction in ionic liquid is described.