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CONDITIONS FOR UNIFORMLY NON-CONFOUNDING OF CAUSAL DISTRIBUTION EFFECTS OVER MULTIPLE COVARIATES

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Journal of Systems science & Complexity 2010年第4期23卷 796-803页

作者： Xueli WANG school of science,beijing university of posts and Telecommunications,beijing 100876,china. school of science Beijing University of Posts and Telecommunications

Causation is a distinct concept from association and more important than association inepidemiologic *** paper proposes the concept of uniform non-confounding for causal distributioneffects over multiple covariates,and gives the sufficient conditions for uniform non-confoundingover a covariate set C including confounders or non-confounders,and also shows the conditions forconditionally non-confounding in the *** these conditions can be tested by observeddata.

关键词： Causal distribution effect confounding covariates uniform non-confounding

TWO-AGENT PARETO OPTIMAL COOPERATIVE INVESTMENT IN INCOMPLETE MARKET:AN EQUIVALENT CHARACTERIZATION

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Journal of Systems science & Complexity 2011年第4期24卷 701-710页

作者： Qing zhou school of science Beijing University of Posts and Telecommunications Beijing 100876 China.

This paper studies the following cooperative investment game with two agents. At the start of the game, both the agents＇ capital are collected. The total capital are then invested according to a certain trading strategy. At a certain time To one agent quits the cooperation and they divide the wealth among themselves. During the remaining period [To, T], the other agent invests his/her capital following a possibly different trading strategy. By stochastic optimization method combined with the theory of Backward Stochastic Differential Equations （BSDEs, for short）, we give an equivalent characterization of the Pareto optimal cooperative strategies.

关键词： Backward stochastic differential equation cooperative investment incomplete market,Pareto optimum stochastic utility.

Neighborhood-following algorithms for linear programming

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science china Mathematics 2004年第6期47卷 812-820页

作者： Al Wenbaoschool of science, beijing university of posts and Telecommunications, beijing 100876, china 1. school of science Beijing University of Posts and Telecommunications 100876 Beijing China

In this paper, we present neighborhood-following algorithms for linear programming. When the neighborhood is a wide neighborhood, our algorithms are wide neighborhood primal-dual interior point algorithms. If the neighborhood degenerates into the central path, our algorithms also degenerate into path-following algorithms. We prove that our algorithms maintain the O9√nL) -iteration complexity still, while the classical wide neighborhood primal-dual interior point algorithms have only the O(nL-iteration complexity. We also proved that the algorithms are quadratic convergence if the optimal vertex is nondegenerate. Finally, we show some computational results of our algorithms.

关键词： linear programming primal-dual interior point methods wide neighborhood methods quadratic convergence

STABIliTY OF GENERAliZED JACKSON NETWORKS WITH INFINITE SUPPLY OF WORK

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Journal of Systems science & Complexity 2008年第2期21卷 283-295页

作者： Yongjiang GUO school of science Beijing University of Posts and Telecommunications Beijing 100876 China

A general Jackson network （GJN） with infinite supply of work is considered. By fluid limit model, the author finds that the Markov process describing the dynamics of the GJN with infinite supply of work is positive Harris recurrent if the corresponding fluid model is stable. Furthermore, the author proves that the fluid model is stable if the usual traffic condition holds.

关键词： Fluid limit model general Jackson network (GJN) infinite supply positive Harris recurrent stability.

Through-polymer,via technology-enabled,flexible,lightweight,and integrated devices for implantable neural probes

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Microsystems & Nanoengineering 2024年第2期10卷 279-291页

作者： Cunkai zhou ye Tian Gen li Yifei ye Lusha Gao Jiazhi li Ziwei liu Haoyang Su Yunxiao Lu Meng li Zhitao zhou Xiaoling Wei Lunming Qin Tiger H.Tao liuyang Sun College of Electronics and Information Engineering Shanghai University of Electric PowerShanghaiChina 2020 X-Lab Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghaiChina school of Graduate Study University of Chinese Academy of SciencesBeijingChina State Key Laboratory of Transducer Technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghaiChina Center of Materials science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina school of Physical science and Technology ShanghaiTech UniversityShanghaiChina Center for Excellence in Brain science and Intelligence Technology Chinese Academy of SciencesShanghaiChina Neuroxess Co. Ltd.(Jiangxi)NanchangJiangxiChina Guangdong Institute of Intelligence science and Technology HengqinZhuhaiGuangdongChina Tianqiao and Chrissy Chen Institute for Translational Research ShanghaiChina

In implantable electrophysiological recording systems,the headstage typically comprises neural probes that interface with brain tissue and integrated circuit chips for signal *** advancements in MEMS and CMOS technology have significantly improved these components,their interconnection still relies on conventional printed circuit boards and sophisticated *** conventional approach adds considerable weight and volume to the package,especially for high channel count *** address this issue,we developed a through-polymer via(TPV)method inspired by the through-silicon via(TSV)technique in advanced three-dimensional *** innovation enables the vertical integration of flexible probes,amplifier chips,and PCBs,realizing a flexible,lightweight,and integrated device(FliD).The total weight of the FliDis only 25%that of its conventional counterparts relying on adapters,which significantly increased the activity levels of animals wearing the FliDs to nearly match the levels of control animals without ***,by incorporating a platinum-iridium alloy as the top layer material for electrical contact,the FliD realizes exceptional electrical performance,enabling in vivo measurements of both local field potentials and individual neuron action *** findings showcase the potential of FliDs in scaling up implantable neural recording systems and mark a significant advancement in the field of neurotechnology.

关键词： alloy neural recording

Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of china Universities of posts and Telecommunications 2009年第2期16卷 1-7页

作者： WANG Jian YANG Xun li Dao-ben school of Information Engineering,beijing university of posts and Telecommunications,beijing 100876,china [a]school of Information Engineering beijing university of posts and Telecommunications beijing 100876 china

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

SVM-based loss differentiation algorithm for wired-cum-wireless networks

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The Journal of china Universities of posts and Telecommunications 2009年第4期16卷 104-111页

作者： DENG Qian-hua ,CAI An-ni school of Telecommunication Engineering,beijing university of posts and Telecommunications,beijing 100876,china [a]school of Telecommunication Engineering beijing university of posts and Telecommunications beijing 100876 china

In a hybrid wired-cum-wireless network environment, packet loss may happen because of congestion or wireless link errors. Therefore, differentiating the cause is important for helping transport protocols take actions to control congestion only when the loss is caused by congestion. In this article, an end-to-end loss differentiation mechanism is proposed to improve the transmission performance of transmission control protocol （TCP）-friendly rate control （TFRC） protocol. Its key design is the introduction of the outstanding machine learning algorithm - the support vector machine （SVM） into the network domain to perform multi-metric joint loss differentiation. The SVM is characterized by using end-to-end indicators for input, such as the relative one-way trip time and the inter-arrival time of packets fore-and-aft the loss, while requiring no support from intermediate network apparatus. Simulations are carried out to evaluate the loss differentiation algorithm with various network configurations, such as with different competing flows, wireless loss rate and queue size. The results show that the proposed classifier is effective under most scenarios, and that its performance is superior to the ZigZag, mBiaz and spike （ZBS） scheme.

关键词： machine learning SVM TCP-friendly rate control (TFRC) congestion control

Investigations of Water Flow Behaviors Induced by Local Temperature Variations through a Single Rough Fracture for the Enhanced Geothermal Systems

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Journal of Thermal science 2024年第3期33卷 1055-1064页

作者： li Jiawei ye lin Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China school of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

In recent years,Enhanced Geothermal System(EGS)technologies have been applied to the geothermal resources production in the Hot Dry Rock(HDR).The core of EGS technologies is to adopt hydraulic fracturing in the reservoir to create a connected network of discrete fractures with the consideration of water as a working fluid for hydraulic fracturing and heat *** paper investigates the characteristics of water flow behaviors through a single rough fracture under different temperature and pressure conditions.A single fracture model with rough fracture surfaces is constructed and then characterized,and influences of the anisotropic factor on the average tortuosity and frictional resistance coefficient of water flow through a single fracture with rough surfaces have been compared and *** consideration of other impacting factors(temperature,pressure,fracture roughness),the impact of mass flow rate has also been *** simulation results present that changes of average tortuosity for water flow through a single rough facture are mainly affected by *** can be observed that higher temperature leads to larger average tortuosity but the frictional resistance coefficient shows an opposite *** for pressure conditions,it is found that effects of pressure on average tortuosity and frictional resistance coefficient is very small,which can be neglected under high pressure ***,the average tortuosity shows a progressively linear relationship with the mass flow *** the contrary,the frictional resistance coefficient has a negative relationship with the mass flow *** is revealed that when the mass flow rate reaches a critical point,the influences of temperature on the frictional resistance coefficient will be *** of single rough fractures with different anisotropic factors show that values of average tortuosity and frictional resistance coefficient have positive relationships with the increase

关键词： single rough fracture tortuosity frictional resistance enhanced geothermal system

Location based spectrum sensing performance analysis over fading channels in cognitive radio networks

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The Journal of china Universities of posts and Telecommunications 2010年第5期17卷 26-31页

作者： YAO Hai-peng,zhou Zheng,SUN Xuan,li Bin school of Information and Communication Engineering,beijing university of posts and Telecommunications,beijing 100876,china [a] school of Information Communication Engineering Beijing University of Posts Telecommunications Beijing 100876 China

This paper analyzes the spectrum sensing performance over fading channel,in which a licensee and multiple unlicensed users coexist and operate in the licensed channel in a local *** overall average probabilities of detection and false alarm by jointly taking the fading and the locations of all secondary users into account are derived,and a statistical model of cumulate interference is *** on the cumulate interference,a closed-form expression of outage probability at the primary user’s receiver according to a specific distribution of the fading is ***,the sensing parameters so as to minimize the total spectrum sensing error and maximize the average opportunistic throughput are *** is noted that the overall average performance analysis and results here enable to benchmark the design of specific spectrum sensing algorithms.

关键词： spectrum sensing cognitive radio cumulate interference outage probability