检索结果-南通市图书馆

PPLS: a privacy-preserving location-sharing scheme in mobile online social networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(information sciences) 2020年第3期63卷 173-183页

作者： Chang XU Xuan XIE Liehuang ZHU Kashif SHARIF Chuan ZHANG Xiaojiang DU Mohsen GUIZANI School of computer science and technology Beijing Institute of Technology Department of computer and information sciences Temple University Department of computer science and Engineering Qatar University

The recent proliferation of mobile devices has given rise to mobile online social networks(m OSNs), an emerging network paradigm that uses social networks as its main design element. As one of the most critical components in m OSNs, location sharing plays an important role in helping users share information and strengthen their social bonds, which however may compromise users’ privacy, including location information and social relationship details. To address these challenges, some solutions have been proposed. However, none of them considers the privacy of inter-user threshold distance, which effectively can be used to identify users, their friends, and location information, by malicious or undesired elements of the system. To overcome this limitation, we propose a secure distance comparison protocol. Furthermore,we present a privacy-preserving location-sharing scheme(PPLS), which allows users to build more complex access control policies. The safety of our scheme is validated by the security analysis and the experimental results demonstrate the efficiency of PPLS scheme.

关键词： privacy-preservation location-sharing mobile online social networks

Scalability Analysis of Request Scheduling in Cloud Computing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tsinghua science and technology 2019年第3期24卷 249-261页

作者： Chao Xue Chuang Lin Jie Hu Tsinghua National Laboratory for information science and technology (TNList) & Department of computer science and technology Tsinghua University

Rapid advancement of distributed computing systems enables complex services in remote computing clusters. Massive applications with large-scale and disparate characteristics also create high requirements for computing systems. Cloud computing provides a series of novel approaches to meet new trends and ***, some scalability issues have to be addressed in the request scheduling process and few studies have been conducted to solve these problems. Thus, this study investigates the scalability of the request scheduling process in cloud computing. We provide a theoretical definition of the scalability of this process. By modeling the scheduling server as a stochastic preemptive priority queue, we conduct a comprehensive theoretical and numerical analysis of the scalability metric under different structures and various environment configurations. The comparison and conclusion are expected to shed light on the future design and deployment of the request scheduling process in cloud computing.

关键词： cloud computing request scheduling scalability model evaluation

Electricity Services Based Dependability Model of Power Grid Communication Networking

在线全文

学校读者我要写书评

暂无评论

Tsinghua science and technology 2014年第2期19卷 121-132页

作者： Jiye Wang Kun Meng Junwei Cao Zhen Chen Lingchao Gao Chuang Lin Department of information and Communication State Grid the computer School Beijing Information Science and Technology University Department of computer science and technology Tsinghua University the Research Institute of information technology Tsinghua National Laboratory for Information Science and TechnologyTsinghua University

The technology of Ultra-High Voltage （UHV） transmission requires higher dependability for electric power grid. Power Grid Communication Networking （PGCN）, the fundamental information infrastructure, severs data transmission including control signal, protection signal, and common data services. Dependability is the necessary requirement to ensure services timely and accurately. Dependability analysis aims to predicate operation status and provide suitable strategies getting rid of the potential dangers. Due to the dependability of PGCN may be affected by external environment, devices quality, implementation strategies, and so on, the scale explosion and the structure complexity make the PGCN＇s dependability much challenging. In this paper, with the observation of interdependency between power grid and PGCN, we propose an electricity services based dependability analysis model of PGCN. The model includes methods of analyzing its dependability and procedures of designing the dependable strategies. We respectively discuss the deterministic analysis method based on matrix analysis and stochastic analysis model based on stochastic Petri nets.

关键词： power grid communication networking dependability stochastic Petri nets strategy design

Jittor: a novel deep learning framework with meta-operators and unified graph execution

在线全文

学校读者我要写书评

暂无评论

science China(information sciences) 2020年第12期63卷 118-138页

作者： Shi-Min HU Dun LIANG Guo-Ye YANG Guo-Wei YANG Wen-Yang ZHOU Department of computer science and technology Tsinghua University Beijing National Research Center for information science and technology

This paper introduces Jittor, a fully just-in-time(JIT) compiled deep learning framework. With JIT compilation, we can achieve higher performance while making systems highly customizable. Jittor provides classes of Numpy-like operators, which we call meta-operators. A deep learning model built upon these meta-operators is compiled into high-performance CPU or GPU code in real-time. To manage metaoperators, Jittor uses a highly optimized way of executing computation graphs, which we call unified graph execution. This approach is as easy to use as dynamic graph execution yet has the efficiency of static graph execution. It also provides other improvements, including operator fusion, cross iteration fusion, and unified memory.

关键词： deep learning framework meta-operator unified graph execution JIT compilation generative adversarial network

Advances in neural architecture search

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National science Review 2024年第8期11卷 24-38页

作者： Xin Wang Wenwu Zhu Department of computer science and technology Beijing National Research Center for Information Science and Technology Tsinghua University

Automated machine learning(AutoML) has achieved remarkable success in automating the non-trivial process of designing machine learning *** the focal areas of AutoML,neural architecture search(NAS) stands out,aiming to systematically explore the complex architecture space to discover the optimal neural architecture configurations without intensive manual *** has demonstrated its capability of dramatic performance improvement across a large number of real-world *** core components in NAS methodologies normally include(ⅰ) defining the appropriate search space,(ⅱ)designing the right search strategy and(ⅲ) developing the effective evaluation *** early NAS endeavors are characterized via groundbreaking architecture designs,the imposed exorbitant computational demands prompt a shift towards more efficient paradigms such as weight sharing and evaluation estimation,***,the introduction of specialized benchmarks has paved the way for standardized comparisons of NAS ***,the adaptability of NAS is evidenced by its capability of extending to diverse datasets,including graphs,tabular data and videos,etc.,each of which requires a tailored *** paper delves into the multifaceted aspects of NAS,elaborating on its recent advances,applications,tools,benchmarks and prospective research directions.

关键词： machine learning artificial intelligence neural architecture search

Selection of optimal window length using STFT for quantitative SNR analysis of LFM signal

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2013年第1期24卷 26-35页

作者： Qingbo Yin Liran Shen Mingyu Lu Xiangyang Wang Zhi Liu College of information science and technology Dalian Maritime University School of computer and information technology Liaoning Normal University

An adaptive approach to select analysis window param- eters for linear frequency modulated （LFM） signals is proposed to obtain the optimal 3 dB signal-to-noise ratio （SNR） in the short- time Fourier transform （STFT） domain. After analyzing the instan- taneous frequency and instantaneous bandwidth to deduce the relation between the window length and deviation of the Gaus- sian window, high-order statistics is used to select the appropriate window length for STFT and get the optimal SNR with the right time-frequency resolution according to the signal characteristic under a fixed sampling rate. computer simulations have verified the effectiveness of the new method.

关键词： window length selection quantitative signal-to-noise ratio instantaneous bandwidth high-order statistics.

From frequency domain to time domain:performance analysis on cyclic prefixed multi-user single-carrier transmission

在线全文

学校读者我要写书评

暂无评论

science China(information sciences) 2016年第8期59卷 144-152页

作者： Wei PENG Qing F.ZHOU An HUANG Shaodan MA School of Electronics information and Communications Huazhong University of Science and Technology School of computer and information Hefei University of Technology Faculty of science and technology University of Macau

This paper analyzes the performance of cyclic prefixed single-carrier transmission under multiuser interference(MUI). For multi-user receivers using single carrier frequency domain adaptive antenna array,we derive the signal to interference plus noise ratio by analyzing the time domain estimated signal after the transformation from frequency domain to time domain. By assuming the MUI follows the Gaussian distribution,we can derive the analytical expression for the bit error rate(BER) performance. The analytical result is verified by the numerical results generated by Monte Carlo method. It is concluded from the analytical results that if the number of receive antennas goes to infinity as assumed in massive multiple input multiple output(MIMO)system, the BER performance will be determined by two ratios: signal to noise ratio as well as the Nr to U ratio, where Nr is the number of receive antennas and U is the number of users.

关键词： single-carrier transmission multi-user interference frequency domain processing MIMO SCFDAAA

Ubiquitous Mining with Interactive Data Mining Agents

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of computer science & technology 2009年第6期24卷 1018-1027页

作者：吴信东朱兴全陈琪君王飞跃 School of computer science and information Engineering Hefei University of Technology Department of computer science University of Vermont Faculty of Engineering and information technology University of Technology Institute of Automation Chinese Academy of Sciences

Due to the increasing availability and sophistication of data recording techniques, multiple information sources and distributed computing are becoming the important trends of modern information systems. Many applications such as security informatics and social computing require a ubiquitous data analysis platform so that decisions can be made rapidly under distributed and dynamic system environments. Although data mining has now been popularly used to achieve such goals, building a data mining system is, however, a nontrivial task, which may require a complete understanding on numerous data mining techniques as well as solid programming skills. Employing agent techniques for data analysis thus becomes increasingly important, especially for users not familiar with engineering and computational sciences, to implement an effective ubiquitous mining platform. Such data mining agents should, in practice, be intelligent, complete, and compact. In this paper, we present an interactive data mining agent - OIDM （online interactive data mining）, which provides three categories （classification, association analysis, and clustering） of data mining tools, and interacts with the user to facilitate the mining process. The interactive mining is accomplished through interviewing the user about the data mining task to gain efficient and intelligent data mining control. OIDM can help users find appropriate mining algorithms, refine and compare the mining process, and finally achieve the best mining results. Such interactive data mining agent techniques provide alternative solutions to rapidly deploy data mining techniques to broader areas of data intelligence and knowledge informaties.

关键词： information systems human-centered computing data mining intelligent agents

A Double Auction Mechanism for Heterogeneous Multi-unit Spectrum Trading

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2016年第5期25卷 928-935页

作者： SUN Yu'e LI Meixuan HUANG He TIAN Miaomiao LI Fanzhang HUANG Liusheng School of Urban Rail Transportation Soochow University School of computer and Software Nanjing University of Information Science and Technology School of computer science and technology Soochow University School of computer science and technology University of Science and Technology of China

The last decade has witnessed a rapid growth in wireless communications technology, and as a result the demand for spectrum resources increased ***, many new wireless demanders cannot access the limited wireless licenses in time while large chunks of spectrum are idle. To solve this, we design a multiunit double auction mechanism for heterogeneous spectrum channels, which take the spatial and temporal reuse into consideration. The proposed scheme first introduces the multi-participants multi-heterogeneous-spectrum trading double auction to illustrate the system model. Some techniques such as spectrum categorize, virtual sellers and buyers’ conflict graph construction, and reconstruction of buyer groups are adopted to achieve a high efficiency of the algorithm. Then, we also prove the truthfulness, individual rationality, and budget balance of the proposed scheme. Finally, the simulation results show that the practical performance of the proposed scheme can efficiently improve the spectrum transaction ratio, reuse ratio, and the buyer’s satisfactory ratio.

关键词： Wireless communications Spectrum auction Spatial and temporal reuse Heterogeneous spectrum Double auction