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mViewer： mobile phone spatiotemporal data viewer

Frontiers of Computer Science 2014年第2期8卷 298-315页

作者： Jiansu PU Siyuan LIU Panpan XU Huamin QU Lionel m. ni Department of Computer Science Hong Kong University of Science and Technology Hong Kong 999077 China iLab Heinz College Carnegie Mellon University Pittsburgh PA 15601 USA

Nowadays movement patterns and people＇s be- havioral models are needed for traffic engineers and city plan- ners. These observations could be used to reason about mobil- ity and its sustainability and to support decision makers with reliable information. The very same knowledge about human diaspora and behavior extracted from these data is also valu- able to the urban planner, so as to localize new services, orga- nize logistics systems and to detect changes as they occur in the movement behavior. moreover, it is interesting to inves- tigate movement in places like a shopping area or a working district either for commercial purposes or for improving the service quality. These kinds of tracking data are made avail- able by wireless and mobile communication technologies. It is now possible to record and collect a large amount of mobile phone calls in a city. Technologies for object tracking have recently become affordable and reliable and hence we were able to collect mobile phone data from a city in China from January 1, 2008 to December 31, 2008. The large amount of phone call records from mobile operators can be considered as life mates and sensors of persons to inform how many peo- ple are present in any given area and how many are entering or leaving. Each phone call record usually contains the caller and callee IDs, date and time, and the base station where the phone calls are made. As mobile phones are widely used in our daily life, many human behaviors can be revealed by an- alyzing mobile phone data. Through mobile phones, we can learn the information about locations, communications be- tween mobile phone users during their daily *** this work, we propose a comprehensive visual analysissystem named as mViewer, mobile phone spatiotemporal data Viewer, which is the first system to visualize and analyze the population＇s mobility patterns from millions of phone call records. Our system consists of three major components： 1） visual analysis of user groups in

关键词： visual analysis mobility pattern mobile phone

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Position-sensitive detectors based on two-dimensional materials

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Nano Research 2021年第6期14卷 1889-1900页

作者： Wenhui Wang Junpeng Lu Zhenhua ni School of Physics and Key Laboratory of mEmS of the ministry of Education Southeast UniversityNanjing211189China

Two-dimensional(2D)materials have attracted great attention in optoelectronics because of their unique structure,optical and electrical *** high-performance photodetectors and implementing their applications are eager to promote the development of 2D ***-sensitive detector(PSD)is an optical inspection device for the precise measurements of position,distance,angle,and other relevant physical *** is a widely used component in the fields of tracking,aerospace,nanorobotics,and so ***,PSD is also a photodetector based on the lateral photovoltaic effect(LPE).This article reviews recent progress in high-performance PSD based on 2D *** high-sensitive photodetectors and LPE involved in 2D photodetectors are firstly ***,we introduce the research progress of PSD based on 2D materials and analyze the carrier dynamics in different device ***,we summarize the functionalities and applications of PSD based on 2D materials,and highlight the challenges and opportunities in this research area.

关键词： two-dimensional(2D)materials graphene photodetector lateral photovoltaic effect position-sensitive detector heterojunction

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multi-physical modeling and Adjusting for Ultrasonic Assisted Soft Abrasive Flow Processing

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Chinese Journal of mechanical Engineering 2023年第4期36卷 111-124页

作者： Yesha ni Yunfeng Tan Dapeng Tan Key Lab of E&m Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China Collaborative Innovation Center of High-end Laser manufacturing Equipment Zhejiang Province&Ministry of EducationHangzhou 310014China

The polishing efficiency of the soft abrasive flow(SAF)method is low,which is not in line with the concept of carbon emission reduction in industrial *** address the above issue,a two-phase fluid multi-physics modeling method for ultrasonic-assisted SAF processing is *** acoustics-fluid coupling mechanic model based on the realizable k-ε model and Helmholtz equation is built to analyze the cavitation *** results show that the pro-posed modeling and solution method oriented to ultrasonic-assisted SAF processing have better revealed the flow field evolution *** turbulence kinetic energy at different ultrasonic frequencies and amplitudes is *** results show that the ultrasonic vibration can induce a cavitation effect in the constrained flow chan-nel and promote the turbulence intensity and uniformity of the abrasive flow.A set of comparative polishing experiments with or without ultrasonic vibration are conducted to explore the performance of the proposed *** can be found that the ultrasonic-assisted SAF method can improve the machining efficiency and uniformity,to achieve the purpose of carbon emission *** relevant result can offer a helpful reference for the SAF method.

关键词： Soft abrasive flow Ultrasonic vibration Cavitation effect Polishing efficiency Turbulent kinetic energy

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STEP-LIKE CONTRAST STRUCTURE OF SINGULarLY PERTURBED OPTImAL CONTROL PROBLEm＊

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Journal of Computational mathematics 2012年第1期30卷 2-13页

作者： mingkang ni Limeng Wu Department of mathematics East China Normal UniversityShanghai 200241China

The existence of step-like contrast structure for a class of singularly perturbed optimal control problem is presented by contrast structure theory. By means of direct scheme of boundary function method, we construct the uniformly valid asymptotic solution for the singularly perturbed optimal control problem. As an application, an example is given to illustrate the main result in this paper.

关键词： Singular perturbation Optimal control problem Contrast structure.

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Interval design point method for calculating the reliability of structural systems

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Science China(Physics,mechanics & Astronomy) 2013年第11期56卷 2151-2161页

作者： ni Zao QIU ZhiPing Shanghai Aircraft Design and Research institute COMAC Institute of Solid mechanics Beijing University of Aeronautics and Astronautics

The evaluation of reliability for structural system is important in engineering *** this paper,by combining the design point method,JC method,interval analysis theory,and increment load method,we propose a new interval design point method for the reliability of structural systems in which the distribution parameters of random variables are described as interval *** proposed method may provide exact probabilistic interval reliability of structures whose random variables can have either a normal or abnormal distribution *** last,we show the feasibility of the proposed approach through a typical example.

关键词： probability design point method interval analysis probabilistic interval reliability parameters uncertainty

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The Cotorsion Pair Cogenerated by the Subcategory of Stable Functors in ((R-mod)^op, Ab)

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Algebra Colloquium 2019年第2期26卷 259-270页

作者： Xianhui Fu meiyuan ni School of mathematics and Statistics Northeast Normal University Changchun 130024 China

Let R be an associative ring with identity. Denote by ((R-mod)^op, Ab) the category consisting of contravariant functors from the category of finitely presented left R-modules R-mod to the category of abelian groups Ab. An object in ((R-mod)^op, Ab) is said to be a stable functor if it vanishes on the regular module R. Let T be the subcategory of stable functors. There are two torsion pairs t1=(Gen(-,R),T)and t2=(T,F1), where 1 is the subcategory of ((R-mod)^op, Ab) consisting of functors with flat dimension at most 1. In this article, let R be a ring of weakly global dimension at most 1, and assume R satisfies that for any exact sequence 0 → m → N → K → 0, if m and N are pure injective, then K is also pure injective. We calculate the cotorsion pair (⊥T,(⊥T)⊥)cogenerated by T clearly. It is shown that G∈⊥T if and only if G/t1(G) is a projective object in T, i.e., G/t1(G)=(-,m) for some R-module m;and G∈(⊥T)⊥ if and only if G/t2(G) is of the form (-, E), where E is an injective R-module.

关键词： stable functors cotorsion pairs torsion pairs

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Ultra-thin, planar, Babinet-inverted plasmonic metalenses

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Light(Science & Applications) 2013年第1期2卷 170-175页

作者： Xingjie ni Satoshi Ishii Alexander V Kildishev Vladimir m Shalaev School of Electrical and Computer Engineering and Birck Nanotechnology Center Purdue UniversityWest LafayetteIN 47907USA

We experimentally demonstrate the focusing of visible light with ultra-thin,planar metasurfaces made of concentrically perforated,30-nm-thick gold *** perforated nano-voids—Babinet-inverted(complementary)nano-antennas—create discrete phase shifts and form a desired wavefront of cross-polarized,scattered *** signal-to-noise ratio in our complementary nano-antenna design is at least one order of magnitude higher than in previous metallic nano-antenna *** first study our proof-of-concept‘metalens’with extremely strong focusing ability:focusing at a distance of only 2.5 mm is achieved experimentally with a 4-mm-diameter lens for light at a wavelength of 676 *** then extend our work with one of these‘metalenses’and achieve a wavelength-controllable focal *** characterization of the lens confirms that switching the incident wavelength from 676 to 476 nm changes the focal length from 7 to 10 mm,which opens up new opportunities for tuning and spatially separating light at different wavelengths within small,micrometer-scale *** the proposed designs can be embedded on-chip or at the end of an optical *** designs also all work for two orthogonal,linear polarizations of incident light.

关键词： metalens nano-antennas plasmonics wavefront shaping

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Spatial analysis and structure of a cross-timber stand in the TallGrass Prairie Preserve (Pawhuska, Oklahoma)

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Journal of Forestry Research 2013年第1期24卷 47-52页

作者： José Ramón arévalo Departamento de Ecología Facultad de BiologíaUniversidad de La LagunaLa Laguna 38206Spain

I analyzed the spatial distribution and structure of trees in a cross timber forest in the Tallgrass Prairie Preserve （Pawhuska, Oklahoma, USA）. I mapped and measured diameter of all stems, saplings （〉1.5 m tall） and dead trees in a 4-ha plot. The stand was dominated by Quercus stellata and Q. marilandica. In total, I mapped 7,636 trees, consisting of 6,785 Q. stellata, 846 Q. marilandica, 2 Celtis occidentalis, 1 Fraxinus pensilvanica and 2 Prunus americana. For saplings, I mapped 54 Q. stellata and 21 Q. marilandica. The size class distribution of the two dominant species did not differ. The dominant mortality class was “standing dead”, while I only found saplings less than 2 m tall. The spatial distribution of the species indicated segregation in the use of the environment, generating a clumped univariate distribution of stems of the same species within radii of 30 m, but repulsion outside 30 m. This segregation can be explained by the different ecological requirements of each species.

关键词： conservation point pattern analysis Quercus stellata Q.marilandica size class distribution

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NUmERICAL　SImULATION　OF　THE　TURBULENT　FLUID　FLOW　AND　PREDICTION　OF　INCIPIENT　CAVITATION　NUmBER　ON　ISOLATED　SURFACE　TRIANGULar　PROTRUSION

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Journal of Hydrodynamics 1996年第1期8卷 67-75页

作者： Ren, Bing ni, Hangen Dalian Univ of Technology Dalian China

For any type of 2-dimensional flowing field, this paper has developed a very effective numerical technique in generating orthogonal computation grids, which shows a wide promise especially for microscale arbitrary shapes concerned. In simulating high speed flowing, it has been verified that Dynamic SGS model is a reliable tool available to engineers, especially in predicting inhomogeneous turbulence nowing. On the basis of physical and numerical methods, this paper has presented, respectively, experimental expression and numerical results for incipient cavitation number. For velocity no more than 15m/s, it was verified that the value of incipient cavitation number from the two different sources approximately coincided with each other.

关键词： numerical simulations turbulence model incipient cavitation

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Resistant patterns of Pseudomonas aeruginosa in a malaysian teaching hospital

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Asian Pacific Journal of Tropical medicine 2009年第6期2卷 59-62页

作者： Zaidah ar Siti SmN Zahiruddin Wm Zeehaida m Department of medical microbiology and Parasitology School of Medical SciencesUniversiti Sains MalaysiaKelantanMalaysia Department of Community medicine School of Medical SciencesUniversiti Sains MalaysiaKelantanMalaysia

Objective:Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of nosocomial infections. Currently a notable increase in the prevalence of multidrug-resistant *** worldwide has been reported in hospitalized patients and was associated with high morbidity and ***:A retrospective laboratory based analysis regarding the spectrum and distribution of *** from a wide range of clinical samples in Hospital Universiti Sains malaysia since January 2003 to December 2007 was ***: Altogether,there were 2 308 clinical isolates *** main sources of *** were from swab,respiratory,urine and blood specimens which accounted for 28.2%,21.8%,13.2%and 12.8% *** showed significant reduction in percentage of resistant towards three antibiotic namely ciprofloxacin,ceftazidime and *** the percentage of pan-resistant *** increased steadily over these ***:This data is helpful to the clinician in guiding the choice of appropriate antibiotic to treat *** *** the same time,it warrants a more aggressive infection control activity to be implemented to control the spread of pan resistant strain in this centre.

关键词： Pseudomonas aeruginosa Resistant pattern Infection

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