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A new smoothing scheme for mathematical programs with complementarity constraints

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science China Mathematics 2010年第7期53卷 1881-1890页

作者： YAN Taodepartment of information and Computational {2.s, College of {2., nanjing university of {2. and technology, nanjing 2.0094, China department of information and Computational {2.s College of Science Nanjing University of Science and Technology

In this paper, we consider a mathematical program with complementarity constraints (MPCC). We present a new smoothing scheme for this problem, which makes the primal structure of the complementarity part unchanged mostly. For the new smoothing problem, we show that the linear independence constraint qualification (LICQ) holds under some conditions. We also analyze the convergence behavior of the smoothing problem, and get some sufficient conditions such that an accumulation point of stationary points of the smoothing problems is C (M, B)-stationarity respectively. Based on the smoothing problem, we establish an algorithm to solve the primal MPCC problem. Some numerical experiments are given in the paper.

关键词： mathematical program with complementarity constrains MPEC-LICQ B-stationarity C-stationarity M-stationarity

Sufficient and necessary conditions for Lyapunov stability of Lorenz system and their application

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science China(information sciences) 2010年第8期53卷 1574-1583页

作者： LUO Qi 1 , LIAO XiaoXin 2.& ZENG ZhiGang 2.1 College of information and Control, nanjing university of information science and technology,{2., China 2.department of Control science and Engineering, Huazhong university of science and technology, Image Processing and Intelligent Control Key Laboratory of Education Ministry of China, Wuhan 430074, China College of information and Control Nanjing University of Information Science and Technology department of Control science and Engineering Huazhong University of Science and Technology Image Processing and Intelligent Control Key Laboratory of Educatio

The sufficient and necessary conditions for Lyapunov stability of the zero equilibrium point of Lorenz system are discussed, and some brief criteria are presented for globally exponential stability, globally asymptotical stability and instability. Furthermore, the behavior of the non-zero equilibrium point of Lorenz system is also investigated, and several sufficient and necessary conditions are provided for locally exponential stability and instability. The established theorems in this paper develop and extend the existing achievements on Lyapunov stability of Lorenz system. In conclusion, by applying the obtained results, some less conservative feedback-control laws are derived to guarantee the globally exponential stability of the chaos control of Chen system, Lu¨ system, Yang-Chen system and Yu-Xia Li system.

关键词： Lorenz system Lyapunov stability sufficient and necessary condition bifurcation values globally exponential synchronization

Features of aerosol optical depth and its relation to extreme temperatures in China during 1980–2.01

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Acta Oceanologica Sinica 2011年第2期30卷 33-45页

作者： HU Ting SUN Zhaobo LI Zhaoxin Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Scienceand Technology Nanjing 210044 China The department of Atmospheric science Nanjing University of Information Science andTechnology Nanjing 210044 China Laboratoire de Meteorologie Dynamique CNRS France

Based on Total Ozone Mapping Spectrometer （TOMS） monthly aerosol optical thickness （AOT） measurements in 1980–2.01 a study is made of space/time patterns and difference between land and sea of AOT 0.50 μm thick over China,which are put into correlation analysis with synchronous extreme temperature indices （warm/cold day and night）.Results suggest that 1） the long-term mean AOT over China is characterized by typical geography,with pronounced land-sea *** AOT has significant seasonality and its seasonal difference is diminished as a function of latitude.2. On the whole,the AOT displays an appreciably increasing trend,with the distinct increase in the eastern Qinghai-Tibetan plateau and SW China,North China,the mid-lower Changjiang （MiLY） valley as well as the South China Sea,but marginal decrease over western/northern Xinjiang and part of South China.3） The AOT over land and sea is marked by conspicuous intra-seasonal and -yearly oscillations,with remarkable periods at one-,two-yr and more （as interannual periods）.4） Land AOT change is well correlated with extremely temperature ***,the correlations of AOT to the extreme temperature indices are more significant in Eastern China with 110 ° E as the *** high-correlation regions are along the Southern China coastline,the Loess Plateau and the Sichuan Basin,and even higher in North China Plain and the mid-lower Changjiang River reaches.5） Simulations of LMDZ-regional model indicate that aerosol effects may result in cooling all over China,particularly in Eastern *** contribution of aerosol change may result in more decrease in the maximum temperature than the minimum,with decrease of 0.11/0.08 K for zonal average,respectively.

关键词： aerosol optical thickness extreme temperature index space/time pattern trend correlation

Spatial and Temporal Variability of N, P and K Balances for Agroecosystems in China

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Pedosphere 2005年第3期15卷 347-355页

作者： SHENRun-Ping SUNBo ZHAOQi-Guo InstituteofSoilscience ChineseAcademyofSciencesNanjing210008（China）／／DepartmentofSpatialInformationScienceNanjingUniversityofInformationScienceandTechnologyNanjing210044（China） InstituteofSoilscience ChineseAcademyofSciencesNanjing210008（China）

Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2.01 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2.01 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997—2.01. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2.01 even though from 1999 to 2.01 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992. 1996 and 2.01, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.

关键词： China economic factors NPK balance spatial and temporal variability

Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2. Wu Yigen3 and Guo Shengli3(1. College of Life sciences, Zhejiang university, Hangzhou 310058, China 2. Imaging {2. of Tongji Hospital of Tongji university, Shanghai 2.0065, China 3. College of Mathematics and Physics, nanjing university of information science and technology, nanjing 2.0044, China) College of Life sciences Zhejiang University Hangzhou 310058 China Imaging department of Tongji Hospital of Tongji university Shanghai 200065 China College of Mathematics and Physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.

A Note on the Completeness of an Exponential Type Sequence

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Chinese Annals of Mathematics,Series B 2011年第4期32卷 527-532页

作者： Jinhui FANG department of Mathematics Nanjing University of Information Science and Technology Nanjing 210044 China

For any given coprime integers p and q greater than 1, in 1959, B proved that all sufficiently large integers can be expressed as a sum of pairwise terms of the form p^aq^b. As Davenport observed, Birch＇s proof can be modified that the exponent b can be bounded in terms of p and q. In 2.00, N. Hegyvari effective version of this bound. The author improves this bound.

关键词： Complete sequence Coprime Residue J. Birch distinct to show gave an

Performance analysis of variable-power adaptive modulation in space-time block coded MIMO diversity systems

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science China(information sciences) 2010年第10期53卷 2106-2115页

作者： YU XiangBin 1,2.& SHI HuiBin 1 1 College of information science and {2., nanjing university of Aeronautics and Astronautics, nanjing 2.0016, China 2.National Mobile Communications Research Laboratory, Southeast university, nanjing 2.0096, China College of information science and {2. Nanjing University of Aeronautics and Astronautics National Mobile Communications Research Laboratory Southeast University

In this paper, the performance analysis of multi-antenna MIMO systems with variable-power (VP) adaptive modulation and space-time coding is presented. The fading gain value is partitioned into a number of regions by which we decide the transmission power according to the region the fading gain falls in. The optimum fading gain region boundaries (switching thresholds) for maximizing spectrum efficiency (SE) under a target BER and average power constraint are derived. It is shown that the Lagrange multiplier in the constrained SE optimization will be unique if the existence condition for multi-antenna systems is satisfied, and is unique for single antenna systems. A practical iterative calculation method based on Steepest Descent Algorithm for finding the Lagrange multiplier is proposed. With the switching thresholds, the closed-form expressions of the SE and average BER, respectively for VP system and constant-power (CP) system are achieved. Simulation results for SE and average BER are in good agreement with the theory analysis. The results show that VP adaptive modulation with space-time coding provides better SE than the counterpart with CP under a target BER and average power constraint.

关键词： adaptive modulation variable power space-time block code constant power multiple input multiple output (MIMO)

Optimal MAC based cooperative spectrum sensing in cognitive radio networks

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science China(information sciences) 2012年第6期55卷 1388-1396页

作者： CHEN Zhong 1,ZHANG XianDa 1 & YANG LanJuan 2.1 State Key Laboratory of Intelligent technology and Systems,Tsinghua National Laboratory for information {2. and technology,department of Automation,Tsinghua university,Beijing 100084,China 2.Institute of Command Automation,PLA university of {2. and technology,nanjing 2.0007,China State Key Laboratory of Intelligent technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Automation Tsinghua University Institute of Command Automation PLA University of Science and Technology

This paper considers a cognitive radio (CR) system in non-ideal fading wireless channels and pro-poses cooperative spectrum sensing schemes based on coherent multiple access channels (MAC),serving as an alternative way to improve the cooperative spectrum sensing performance and provide space diversity for spec-trum *** statistics are transmitted using a common channel from the secondary users (SUs) to a fusion center (FC) where the global decision is *** optimal scaling factors of the proposed schemes are obtained by maximizing the detection probability under a target false alarm probability and a transmit power *** the proposed optimal MAC scheme has high computational complexity,a sub-optimal solu-tion based on maximization of the deflection coefficient (DC) is also *** results show that the proposed algorithms can significantly improve the spectrum sensing performance and approach the detection baseline.

关键词： cognitive radio (CR) spectrum sensing multiple access channel (MAC) deflection coefficient optimization

The optimization of replica distribution in the unstructured overlays

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science China(information sciences) 2012年第3期55卷 714-722页

作者： FENG GuoFu1,2., LI WenZhong2. LU SangLu2. CHEN DaoXu2.& BUYYA Rajkumar3 1School of information science, {2. Audit university, {2. 2.002., China 2.tate Key Laboratory of Novel Software technology, {2. university, {2. 2.0093, China 3department of Computer science and Software Engineering, The university of Melbourne, Victoria 3010, Australia School of information science Nanjing Audit University State Key Laboratory of Novel Software technology Nanjing University

Replication is a widely used technique in unstructured overlays to improve content availability or system performance. A fundamental question often addressed by previous work focused on: how many replicas ought to be allocated for each data item given the fixed query rates and limited storage capability? In this paper, we have put forth two optimal replica distributions to achieve the highest success rate and the lowest message consumption. Especially, we have investigated the influence of item size on replica distribution. Our results show that Square-Root Replication, which is traditionally considered to be optimal, is not always the best choice. Our study offers a new deep understanding of resource managment in self-organized unstructured overlays.

关键词： unstructured overlay item size distribution query rate success rate expected search size