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Comparisons of three data storage models in parametric temporal databases

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Journal of Central South University 2013年第7期20卷 1919-1927页

作者： Seo-Young NOH Shashi k. GADIA Haengjin JANG Supercomputing Center Korea Institute of Science and Technology Information Department of Computer Science Iowa State University

The parametric temporal data model captures a real world entity in a single tuple, which reduces query language complexity. Such a data model, however, is difficult to be implemented on top of conventional databases because of its unfixed attribute sizes. XML is a matured technology and can be an elegant solution for such challenge. Representing data in XML trigger a question about storage efficiency. The goal of this work is to provide a straightforward answer to such a question. To this end, we compare three different storage models for the parametric temporal data model and show that XML is not worse than any other approaches. Furthermore, XML outperforms the other storages under certain conditions. Therefore, our simulation results provide a positive indication that the myth about XML is not true in the parametric temporal data model.

关键词： data representation parametric data model XML-based representation

十字路口的中国管理研究:一些哲学层面的思考

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重庆大学学报（社会科学版） 2011年第4期17卷 13-18页

作者：曾荣光得克萨斯大学

这篇评论从哲学层面讨论一些关于中国管理研究情境化的问题。首先需要注意的是,不同的哲学派系可以对情境化进行不同的解释;其次,根据迪昂-奎因(Duhem-Quine)论题,实证普适性的重复检验是一种适合在中国情境下测试西方理论的方法;第三,... 详细信息

这篇评论从哲学层面讨论一些关于中国管理研究情境化的问题。首先需要注意的是,不同的哲学派系可以对情境化进行不同的解释;其次,根据迪昂-奎因(Duhem-Quine)论题,实证普适性的重复检验是一种适合在中国情境下测试西方理论的方法;第三,由于难以确定性地推翻已有的管理理论,试图创造新的理论来解释独特的中国管理现象,可能导致理论的过度繁衍,并延续薄弱甚至虚假的理论;最后,文章建议用实证规律式的研究作为理论应用和理论创新以外的另一选择。

关键词：情境化迪昂-奎因(Duhem-Quine)论题重复检验实证规律理论的过度繁衍

Free vibration and critical speed of moderately thick rotating laminated composite conical shell using generalized differential quadrature method

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Applied Mathematics and Mechanics(English Edition) 2013年第4期34卷 437-456页

作者： k.DANESHJOU M.TALEBITOOTI R.TALEBITOOTI School of Mechanical Engineering Iran University of Science and Technology School of Automotive Engineering Iran University of Science and Technology

The generalized differential quadrature method （GDQM） is employed to con- sider the free vibration and critical speed of moderately thick rotating laminated compos- ite conical shells with different boundary conditions developed from the first-order shear deformation theory （FSDT）. The equations of motion are obtained applying Hamilton＇s concept, which contain the influence of the centrifugal force, the Coriolis acceleration, and the preliminary hoop stress. In addition, the axial load is applied to the conical shell as a ratio of the global critical buckling load. The governing partial differential equations are given in the expressions of five components of displacement related to the points ly- ing on the reference surface of the shell. Afterward, the governing differential equations are converted into a group of algebraic equations by using the GDQM. The outcomes are achieved considering the effects of stacking sequences, thickness of the shell, rotating velocities, half-vertex cone angle, and boundary conditions. Furthermore, the outcomes indicate that the rate of the convergence of frequencies is swift, and the numerical tech- nique is superior stable. Three comparisons between the selected outcomes and those of other research are accomplished, and excellent agreement is achieved.

关键词： generalized differential quadrature method (GDQM) natural frequency,rotating conical shell first-order shear deformation theory (FSDT) critical speed

High permittivity and low dielectric loss analysis of lead free Sr_(1-x)La_x(Ti_(0.5) Fe_(0.5))O_3

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Journal of Central South University 2013年第12期20卷 3363-3371页

作者： M.R.Shah A.k.M.Akther Hossain Department of Physics Primeasia University Department of Physics Bangladesh University of Engineering and Technology

The structural and electrical properties of lead free Srx-xLax（***.5）O3 （SLTFO） prepared by standard solid state reaction technique were studied. The X-ray diffraction analysis confirmed the formation of a single-phase cubic perovskite structure. The compositional dependence of lattice constant, density and microstructural studies show that they vary significantly with La3＋ content. when measured at 10 kHz, all the compositions of SLTFO at room temperature exhibit a high permittivity （about 104） and low dielectric loss （about 10-3）. SLTFO also display minimum dielectric loss within the lower and higher limits of frequency, indicating that the samples are of good quality. It is concluded from the calculated ac conductivity that the conduction is due to mixed polarons hopping. The complex impedance plot exhibits a tendency of forming a single semicircular arc for all compositions, which implies a dominance of grain boundary resistance on the impedance. Impedance parameters were determined by fitting the experimental data with Cole-Cole empirical formula. The results of the present experiment indicate that the lead free SLTFO materials with higher permittivity and lower dielectric loss have possible practical applications.

关键词： dielectric properties solid state reaction Sr titanate X-ray diffraction

Influence of volume percentage of NanoTiB2 particles on tribological&mechanical behaviour of 6061-T6 Al alloy nano-surface composite layer prepared via friction stir process

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Defence Technology（防务技术） 2017年第1期13卷 16-21页

作者： V.kishan Aruri Devaraju k.Prasanna Lakshmi Department of Mechanical Engineering MRCETHyderabadT.S.India Department of Mechanical Engineering SR Engineering CollegeWarangalT.S.India Department of Mechanical Engineering College of EngineeringJNTU ManthiniT.S.India

The aim of present study is to analyze the influence of volume percentage(vol.%) of nano-sized particles(TiB_2: average size is 35 nm) on microstructure, mechanical and tribological behavior of 6061-T6 Al alloy surface nano composite prepared via Friction stir process(FSP). The microstructure of the fabricated surface nanocomposites is examined using optical microscopy(OM) and scanning electron microscope(SEM) for distribution of TiB_2 nano reinforcement particles, thickness of nano composite layer formed on the Aluminum alloy substrate and fracture features. The depth of surface nano composite layer is measured as 3683.82 m m along the cross section of stir zone of nano composite perpendicular to FSP. It was observed that increase in volume percentage of TiB_2 particles, the microhardness is increased up to132 Hv and it is greater than as-received Al alloy's microhardness(104 Hv). It is also observed that at 4volume percentage higher tensile properties exhibited as compared with the 2 and 8 vol. %. It is found that high wear resistance exhibited at 4 volume percentage as-compared with the 2 and 8 vol. %. The observed wear and mechanical properties are interrelated with microstructure, fractography and worn morphology.

关键词： Friction stir process Al alloy Surface nano composites Tensile Tribology

Seasonal variability of ambient NH_3, NO, NO_2 and SO_2 over Delhi

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Journal of Environmental Sciences 2010年第7期22卷 1023-1028页

作者： S.k.Sharma A.Datta T.Saud M.Saxena T.k.Mandal Y.N.Ahammed B.C.Arya Radio and Atmospheric Sciences Division National Physical Laboratory Council of Scientific and Industrial Research (CSIR)

we present the diurnal and seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi, India. Ambient NH3, NO and NO2 were measured continuously during winter, summer and autumn seasons using NH3- and NOx-analyzer, which operates by chemiluminescence method with a higher estimation efficiency （〉 90%） than the chemical trap method （reproducibility 4.7%）. Prominent diurnal, day-to-day and seasonal variations of ambient mixing ratio of NH3, NO, NO2 and SO2 were observed during the study period. Seasonal variation with higher mixing ratio in winter was observed for all measured trace gases except NO. Day-night variation of all measured trace gases observed was higher in winter in comparison with summer. Late morning increase in NO2 mixing ratio might be attributed to conversion of NO to NO2 with the interaction ofO3.

关键词： ambient NH3, diurnal and seasonal variations chemiluminescence method ambient NO, NO2 and SO2

Performance Analysis and Throughput Enhancement of the STET Technique for wLAN IEEE 802.11ad

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Computer Systems Science & Engineering 2022年第2期40卷 571-579页

作者： M.Vanitha J.kirubakaran k.Radhika Department of Electronics and Communication Engineering Saveetha Engineering CollegeChennai602105India Department of Electronics and Communication Engineering Muthayammal Engineering CollegeRasipuram637408India

The IEEE 802.11ad innovation has enabled the impact of remote devices in unauthorized 60 GHz unlicensed frequency band at Giga bits per second information transfer rate in speed concentrated 5G *** have presented an innovative work that deals with the upgradation of the ability of IEEE 802.11ad wireless LAN to make it suitable for wireless *** exact examination on the IEEE 802.11ad analysis has been carried out in this work to achieve the greatest *** has pulled attraction in broad consideration for accomplishing the pinnacle transmission rate of 8 Gbit/*** 802.11ad is a convention utilized for extremely high information rates(around 8 Gbit/s)and for short range remote correspondence of around 1 to 10 *** Multi-layer with Multi-User Multiple Input Multiple-Output(MLMU-MIMO)innovation has enabled transmission of multiple information packets all the while from the wLAN IEEE 802.11 ad Access Point(AP)to various receivers by means of different wireless *** help the MLMU-MIMO innovation at Medium Access Control(MAC),a new method called Simultaneous Transmission for Enhanced Throughput(STET)has been presented for enhancement of the transmission rate of the wireless standard.A mathematical model has been used for the evaluation of the performance of an IEEE 802.11ad AP empowering the STET allocation *** STET model can help determination of the throughput improvement of a STET technique,for example,audio information,images,good quality and foundation *** main goal of this work is to analyze the improvement of the STET allocation technique in regard to the usage of rare frequency band,when obtaining spectrum access between the various access *** theoretical and simulation outcomes are also confirmed by Riverbed modeler 17.5 simulation tool.

关键词： wLAN STET MAC

A control scheme with performance prediction for a PV fed water pumping system

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Frontiers in Energy 2014年第4期8卷 480-489页

作者： Ramesh k GOVINDARAJAN Pankaj Raghav PARTHASARATHY Saravana Ilango GANESAN Department of Electrical and Electronics Engineering National Institute of Technology Tiruchirappalli 620015 India

This paper focuses on modeling and perfor- mance predetermination of a photovoltaic （PV） system with a boost converter fed permanent magnet direct current （PMDC） motor-centrifugal pump load, taking the con- verter losses into account. Sizing is done based on the maximum power generated by the PV array at the average irradiation. Hence optimum sizing of the PV array for the given irradiation at the geographical location of interest is obtained using the predetermined values. The analysis presented here involves systems employing maximum power point tracking （MPPT） as they are more efficient than directly coupled systems. However, the voltage and power of the motor might rise above rated values for irradiations greater than the average when employing MPPT, hence a control scheme has been proposed to protect the PMDC motor from being damaged during these conditions. This control scheme appropriately chooses the optimum operating point of the system, ensuring long-term sustained operation. The numerical simulation of the system is performed in Matlab/Simulink and is validated with experimental results obtained from a 180 V, 0.5 hp PMDC motor coupled to a centrifugal pump. The operation of the system with the proposed control scheme is verified by varying the irradiation levels and the relevant results are presented.

关键词： photovoltaic system boost converter max- imum power point tracking (MPPT) DC permanent-magnet motor centrifugal pump

Capacitance-voltage analysis of a high-k dielectric on silicon

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Journal of Semiconductors 2012年第2期33卷 10-13页

作者： Davinder Rathee Sandeep k.Arya Mukesh kumar Department of Electronics and Communication Engineering Guru Jambeshwer University of Science and TechnologyHisarIndia Department of Electronics Science Kurukshetra UniversityKurukshetraIndia

Device characteristics of TiO;gate dielectrics deposited by a sol-gel method and DC sputtering method on a P-type silicon wafer are ***-oxide-semiconductor capacitors with Al as the top electrode were fabricated to study the electrical properties of TiO;*** films were physically characterized by using X-ray diffraction,a capacitor voltage measurement,scanning electron microscopy,and by spectroscopy *** XRD and DST-TG indicate the presence of an anatase TiO;phase in the *** deposited at higher temperatures showed better *** dielectric constant calculated using the capacitance voltage measurement was found to be 18 and 73 for sputtering and sol-gel samples *** refractive indices of the films were found to be 2.16 for sputtering and 2.42 for sol-gel samples.

关键词： sol-gel method DC reactive sputtering C-V analysis flat band voltage