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Chinese Physics B 2013年第9期22卷 190-196页

作者：顾卫东孙志勇吴晓明于长斌 shandong provincial key laboratory of computer network Shandong Computer Science Center

In this paper, we propose a general method to simultaneously identify both unknown time delays and unknown model parameters in delayed dynamical systems based on the autosynchronization technique. The design procedure is presented in detail by constructing a specific Lyapunov function and linearizing the model function with nonlinear parameterization. The obtained result can be directly extended to the identification problem of linearly parameterized dynamical systems. Two Wpical numerical examples confirming the effectiveness of the identification method are given.

关键词： autosynchronization parameter identification delay identification nonlinear parameterization

Adaptive lag synchronization of uncertain dynamical systems with time delays via simple transmission lag feedback

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Chinese Physics B 2013年第8期22卷 346-355页

作者：顾卫东孙志勇吴晓明于长斌 shandong provincial key laboratory of computer network Shandong Computer Science Center

In this paper we present an adaptive scheme to achieve lag synchronization for uncertain dynamical systems with time delays and unknown parameters. In contrast to the nonlinear feedback scheme reported in the previous literature, the proposed controller is a linear one which only involves simple feedback information from the drive system with signal popagation lags. Besides, the unknown parameters can also be identified via the proposed updating laws in spite of the existence of model delays and transmission lags, as long as the linear independence condition between the related function elements is satisfied. Two examples, i.e., the Mackey-Glass model with single delay and the Lorenz system with multiple delays, are employed to show the effectiveness of this approach. Some robustness issues are also discussed, which shows that the proposed scheme is quite robust in switching and noisy environment.

关键词： adaptive feedback time delay lag synchronization parameter identification noise perturbation

I-sieve: An Inline High Performance Deduplication System Used in Cloud Storage

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Tsinghua science and Technology 2015年第1期20卷 17-27页

作者： Jibin Wang Zhigang Zhao Zhaogang Xu Hu Zhang Liang Li Ying Guo the shandong computer science center (National Supercomputer center in Jinan) Shandong Provincial Key Laboratory of Computer Networks

Data deduplication is an emerging and widely employed method for current storage systems. As this technology is gradually applied in inline scenarios such as with virtual machines and cloud storage systems, this study proposes a novel deduplication architecture called I-sieve. The goal of I-sieve is to realize a high performance data sieve system based on i SCSI in the cloud storage system. We also design the corresponding index and mapping tables and present a multi-level cache using a solid state drive to reduce RAM consumption and to optimize lookup performance. A prototype of I-sieve is implemented based on the open source i SCSI target, and many experiments have been conducted driven by virtual machine images and testing tools. The evaluation results show excellent deduplication and foreground performance. More importantly, I-sieve can co-exist with the existing deduplication systems as long as they support the i SCSI protocol.

关键词： I-sieve cloud storage data deduplication

A Cellular Automata Based Verifiable Multi-secret Sharing Scheme Without a Trusted Dealer

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Chinese Journal of Electronics 2017年第2期26卷 313-318页

作者： LI Meng YU Jia HAO Rong College of computer science and Technology Qingdao University shandong provincial key laboratory of computer network

We proposed a verifiable multi-secret sharing scheme without a *** use cellular automata,having the properties of linear computations and parallel computations,to construct our *** linear computational property makes it possible to build a scheme without the assistance of a trusted dealer,and the parallel computational property contributes to the high efficiency of the *** function is used to realize the verification of shares,which also makes our scheme more *** security of the scheme is also analyzed.

关键词： Multi-secret sharing Verifiability Trusted dealer Cellular automata Hash function

Block diagonalization coordinated transmission with zero-forcing in MIMO broadcast

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The Journal of China Universities of Posts and Telecommunications 2011年第3期18卷 27-33页

作者： WANG Ya-chen MA Xiao-feng LI Ye shandong computer science center Jinan 250014 China shandong provincial key laboratory of computer network Jinan 250014 China

This work has investigated coordinated multiple-input multiple-output （MIMO） transmission schemes in an interference-limited cellular downlink. It has proposed a novel block diagonalization （BD） coordinated transmission scheme, which combines with zero-forcing （ZF） criterion. In the scheme, the BD technique has advantages in suppressing multi-user interference while the ZF technique enables to mitigate interference among spatial data streams for a user. Based on the proposed coordinated scheme, an efficient power allocation is also put forward. The analyses show that the ergodic capacity of the proposed coordinated scheme is that of the MIMO channel with the maximum transmit power at each transmitter. computer simulations demonstrate the effectiveness of the proposed coordinated scheme and its corresponding power allocation.

关键词： BD cellular systems coordinated transmission MIMO power allocation ZF

Flexible paired-orthogonal codes for multi-user MIMO-OFDM

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The Journal of China Universities of Posts and Telecommunications 2011年第1期18卷 36-41页

作者： WANG Ya-chen FAN Yan-hong MA Xiao-feng LI Ye shandong computer science center Jinan 250014 China shandong provincial key laboratory of computer network Jinan 250014 China

The work proposes two novel spreading codes, called extensive double-orthogonal code （EDOC） and flexible paired-orthogonal code （FPOC）, for multi-user downlink multiple-input multiple-output （M1MO） orthogonal frequency division multiplexing （OFDM） systems. The goal of code designs is to obtain an improved bit error rate （BER） performance without loss of bandwidth efficiency. The code designs achieve space diversity by employing multiple antennas at both transmit ends and receive ends. Codes are reasonably spread into time, frequency and space domain. The proposed codes are attractively characterized with length flexibility, which breaks the ＂power of two＂ constraint. The simulation results indicate that the proposed codes improve overall BER performance, by exploiting space diversity gains. The flexibility in code length also results in high spectral efficiency.

关键词： flexible paired-orthogonality MIMO OFDM multi-user space diversity

Primary Exploration of Reliability Evaluation of computer Live Forensics Model on Physical Memory Analysis

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Journal of Harbin Institute of Technology(New Series) 2014年第4期21卷 121-128页

作者： Lian-Hai Wang Qiu-Liang Xu School of computer science and Technology Shandong University shandong provincial key laboratory of computer network Shandong Computer Science Center( National Supercomputer Center in Jinan)

The integrity and fidelity of digital evidence are very important in live forensics. Previous studies have focused the uncertainty of live forensics based on different memory snapshots. However,this kind of method is not effective in practice. In fact,memory images are usually acquired by using forensics tools instead of using snapshots. Therefore,the integrity and fidelity of live evidence should be evaluated during the acquisition process. In this paper,we study the problem in a novel viewpoint. Firstly,several definitions about memory acquisition measure error are introduced to describe the trusty. Then,we analyze the experimental error and propose some suggestions on how to reduce it. A novel method is also developed to calculate the system error in detail. The results of a case study on Windows 7 and VMware virtual machine show that the experimental error has good accuracy and precision,which demonstrate the efficacy of the proposed reducing methods. The system error is also evaluated,that is,it accounts for the whole error from 30% to 50%.

关键词： digital investigation live forensics volatile memory acquisition trusted probability

An Approach to Analyze Physical Memory Image File of Mac OS X

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Journal of Harbin Institute of Technology(New Series) 2014年第4期21卷 116-120页

作者： Li-Juan Xu Lian-Hai Wang shandong provincial key laboratory of computer network Shandong Computer Science Center( National Supercomputer Center in Jinan)

Memory analysis is one of the key techniques in computer live forensics. Especially,the analysis of a Mac OS X operating system's memory image file plays an important role in identifying the running status of an apple computer. However,how to analyze the image file without using extra"mach-kernel"file is one of the unsolved difficulties. In this paper,we firstly compare several approaches for physical memory acquisition and analyze the effects of each approach on physical memory. Then,we discuss the traditional methods for the physical memory file analysis of Mac OS X. A novel physical memory image file analysis approach without using extra"mach-kernel"file is proposed base on the discussion. We verify the performance of the new approach on Mac OS X 10. 8. 2. The experimental results show that the proposed approach is simpler and more practical than previous ones.

关键词： computer forensics live forensics Mac OS X operating system physical memory analysis

Energy efficiency and area spectral efficiency tradeoff for coexisting wireless body sensor networks

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science China Earth sciences 2016年第12期59卷 151-165页

作者： Ruixia LIU Yinglong WANG Shangbin WU Cheng-Xiang WANG Wensheng ZHANG College of Information science and Engineering Shandong University of Science and Technology shandong provincial key laboratory of computer network Shandong Computer Science Center (National Supercomputer Center in Jinan) Institute of Sensors Signals and Systems School of Engineering and Physical Sciences Heriot-Watt University shandong provincial key laboratory of Wireless Communication Technologies School of Information Science and Engineering Shandong University

The coexistence of wireless body sensor networks(WBSNs) is a very challenging problem, due to strong interference, which seriously affects energy consumption and spectral reuse. The energy efficiency and spectral efficiency are two key performance evaluation metrics for wireless communication networks. In this paper, the fundamental tradeoff between energy efficiency and area spectral efficiency of WBSNs is first investigated under the Poisson point process(PPP) model and Matern hard-core point process(HCPP) model using stochastic geometry. The circuit power consumption is taken into consideration in energy efficiency calculation. The tradeoff judgement coefficient is developed and is shown to serve as a promising complementary measure. In addition, this paper proposes a new nearest neighbour distance power control strategy to improve energy efficiency. We show that there exists an optimal transmit power highly dependant on the density of WBSNs and the nearest neighbour distance. Some important properties are also addressed in the analysis of coexisting WBSNs based on the IEEE 802.15.4 standard, such as the impact of intensity nodes distribution,optimal guard zone, and outage probability. Simulation results show that the proposed power control design can reduce the outage probability and enhance energy efficiency. Energy efficiency and area spectral efficiency of the HCPP model are better than those of the PPP model. In addition, the optimal density of WBSNs coexistence is obtained.

关键词： WBSNs coexistence stochastic geometry energy efficiency area spectral efficiency power control

An Unprecedented Efficiency with Approaching 21%Enabled by Additive‑Assisted Layer‑by‑Layer Processing in Organic Solar Cells

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Nano-Micro Letters 2025年第2期17卷 372-375页

作者： Shuai Xu Youdi Zhang Yanna Sun Pei Cheng Zhaoyang Yao Ning Li Long Ye Lijian Zuo Ke Gao key laboratory of Advanced Green Functional Materials College of ChemistryChangchun Normal UniversityChangchun 130032People’s Republic of China shandong provincial key laboratory for science of Material Creation and Energy Conversion School of Chemistry and Chemical EngineeringShandong UniversityQingdao 266237People’s Republic of China College of Polymer science and Engineering Sichuan UniversityChengdu 610065People’s Republic of China State key laboratory and Institute of Elemento‑Organic Chemistry Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer MaterialsRenewable Energy Conversion and Storage Center(RECAST)College of ChemistryNankai UniversityTianjin 300071People’s Republic of China Institute of Polymer Optoelectronic Materials and Devices State key laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640People’s Republic of China Tianjin key laboratory of Molecular Optoelectronic sciences School of Materials Science and EngineeringTianjin UniversityTianjin 300350People’s Republic of China State key laboratory of Silicon Materials MOE Key Laboratory of Macromolecular Synthesis and FunctionalizationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China

Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer *** optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture *** approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

关键词： Organic solar cells Additive-assisted layer-by-layer processing Three-dimensional fibril morphology Bulk p-i-n structure Optical management