检索结果-内蒙古大学图书馆

A compressive sensing approach to urban traffic estimation with probe vehicles

IEEE Transactions on Mobile computing 2013年第11期12卷 2289-2302页

作者： Zhu, Yanmin Li, Zhi Zhu, Hongzi Li, Minglu Zhang, Qian Shanghai Key Lab of Scalable Computing and Systems Shanghai China Department of Computer Science and Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China Department of Computer Science and Engineering Hong Kong University of Science and Technology Academic Building Clear Water Bay Kowloon Hong Kong

Traffic estimation is crucial to a number of tasks such as traffic management and road engineering. We propose an approach for metropolitan-scale traffic estimation with probe vehicles that periodically send location and speed updates to a monitoring center. In our approach, we use the flow speed on a road link within a time slot to indicate the traffic condition of the road segment at the given time slot, which is approximated by the average value of probe speeds. By analyzing a large data set of two-year probe data collected from a fleet of around 4,000 taxis in shanghai, China, we find that a set of probe data may contain a lot of spatiotemporal vacancies over both time and space. This raises a serious missing data problem for road traffic estimation, which results from the naturally uneven distribution of probe vehicles over both time and space. Through empirical study based on the data set of real probe data using principal component analysis (PCA), we have observed that there are hidden structures within the traffic conditions of a road network. Inspired by this observation, we propose a compressive sensing-based algorithm for solving the missing data problem, which exploits the hidden structures for computing estimates for road traffic conditions. Different from existing approaches, our algorithm does not rely on complicated traffic models, which usually require costly training with field study and large data sets. With extensive experiments based on the data set of real probe data, we demonstrate that our proposed algorithm performs significantly better than other completing algorithms, including KNN and MSSA. Surprisingly, our algorithm can achieve an estimate error of as low as 20 percent even when more than 80 percent of probe data are missing. © 2002-2012 IEEE.

关键词： Principal component analysis

来源：评论

学校读者我要写书评

暂无评论

SECOND ORDER VECTOR TAYLOR SERIES BASED ROBUST SPEECH RECOGNITION

SECOND ORDER VECTOR TAYLOR SERIES BASED ROBUST SPEECH RECOGN...

引用

IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Suliang Bu Yanmin Qian Khe Chai Sim Yongbin You Kai Yu MOE-Microsoft Key Lab. for Intelligent Computing and Intelligent Systems Department of Computer Science and Engineering Shanghai Jiao Tong University Department of Computer Science National University of Singapore

ISBN: (纸本)9781479928941

Vector Taylor Series (VTS) model based compensation approach has been successfully applied to various robust speech recognition tasks. In this paper, a novel method to derive the formula to calculate the static and dynamic statistics based on second-order VTS (sVTS) is presented, which provides a new insight on the VTS approximation. Lengthy derivation could therefore be avoided when high order VTS is used and the proposed approach is more compact and easier to implement compared to previous high order VTS approaches. Experiments on Aurora 4 showed that the proposed sVTS based model compensation approach obtained 16.7% relative WER reduction over traditional first-order VTS (fVTS) approach.

关键词： Speech recognition Vessel traffic services VTS formula

来源：评论

学校读者我要写书评

暂无评论

kMemvisor: Flexible system wide memory mirroring in virtual environments

kMemvisor: Flexible system wide memory mirroring in virtual ...

引用

22nd ACM International Symposium on High-Performance Parallel and Distributed computing, HPDC 2013

作者： Wang, Bin Qi, Zhengwei Guan, Haibing Dong, Haoliang Sun, Wei Dong, Yaozu Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai China School of Software Shanghai Jiao Tong University Shanghai China Intel China Software Center Shanghai China

ISBN: (纸本)9781450319102

Today's commercial cloud service providers require the availability with an annual uptime percentage at least 99.95%. While memory errors become norms instead of exceptions with the increasing memory's density and capacity in cloud applications. Thus, uncorrected errors from DRAM can be a significant source of system downtime. To address this increasingly important concern, both hardware and software memory mirroring technologies are studied nowadays to provide memory high availability. However, hardware solutions like mirror memory, which uses doubled chip, need dedicated and costly peripheral hardware. While existing software approaches, i.e., virtual machine's checkpoint technology, reduce the expense but incur the high overhead in practical usage. In this paper, we present a novel system called kMemvisor to provide system-wide high availability memory mirroring. It is a software approach achieving flexible multi-granularity memory mirroring via virtualization and binary translation technology. Specifically, kMemvisor first creates backup space of the same size of the specified memory for applications or virtual machines. We can flexibly set memory areas to be mirrored or not mirrored from application level to system-wide. Then, all memory write instructions in the native memory space are captured and instrumented by mirror memory write instructions to synchronize the data in backup space. Furthermore, this instruction level memory synchronization reduces backup overhead and lowers the probability of data loss compared with traditional software approaches. So kMemvisor could use data from the backup space to recover when memory failures happen. The results show that kMemvisor causes 55% overhead in the worst case of system-wide high availability and 30% average for the real world applications, which outperforms the state-of-the-art software approaches even in the worst case. © 2013 ACM.

关键词： Virtual machine

来源：评论

学校读者我要写书评

暂无评论

IMac: Strategy-proof incentive mechanism for mobile crowdsourcing

IMac: Strategy-proof incentive mechanism for mobile crowdsou...

引用

8th International Conference on Wireless Algorithms, systems, and Applications, WASA 2013

作者： Feng, Zhenni Zhu, Yanmin Ni, Lionel M. Shanghai Key Lab of Scalable Computing and Systems Shanghai Jiao Tong University China Department of Computer Science and Engineering Shanghai Jiao Tong University China Hong Kong University of Science and Technology Hong Kong Hong Kong

ISBN: (纸本)9783642397004

Mobile crowdsourcing with smartphones advocates the cooperative effort of mobile smartphones to perform a joint distributed sensing task, which has gained growing importance for its potential to support a wide spectrum of large-scale sensing applications. Smartphone users in the real world are strategic and rational. Thus, one crucial problem in mobile crowdsourcing with smartphones is to stimulate cooperation from smartphone users. Several major challenges should be addressed. First, the actual cost incurred for a sensing task is private information and unknown to other users and the mobile crowdsourcing platform. Second, smartphone users are strategic, which suggest a user may deliberately misreport its cost (different from the real cost) in order to maximize its own utility. In this paper, we propose a strategy-proof incentive mechanism called iMac based on the Vickrey-Clarke-Groves (VCG) mechanism. The main idea of iMac is to stimulate smartphone users to truthfully disclose their real costs in spite of strategic behavior of the users. iMac introduces two main components. The first component determines the allocation of a sensing task to smartphone users given the user costs. And the second component decides the payment to each user. We prove that iMac can successfully produce a unique Nash equilibrium at which each user truthfully discloses the cost. Meanwhile, the minimization of the social cost is achieved. Simulation results demonstrate iMac achieves the desired design objectives and the overpayment is modest. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Smartphones

来源：评论

学校读者我要写书评

暂无评论

HYBit: A hybrid taint analyzing framework for binary programs

HYBit: A hybrid taint analyzing framework for binary program...

引用

4th International Conference on Advances in Swarm Intelligence, ICSI 2013

作者： Zhu, Erzhou Guan, Haibing Liang, Alei Xu, Rongbin Li, Xuejian Liu, Feng Signal Processing of Ministry of Education School of Computer Science and Technology Anhui University Hefei 230601 China Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai 200240 China

ISBN: (纸本)9783642387142

For the purpose of discovering security flaws in software, many dynamic and static taint analyzing techniques have been proposed. The dynamic techniques can precisely find the security flaws of the software;but it suffers from substantial runtime overhead. On the other hand, the static techniques require no runtime overhead;but it is often not accurate enough. In this paper, we propose HYBit, a novel hybrid framework which integrates dynamic and static taint analysis to diagnose the security flaws for binary programs. In the framework, the source binary is first analyzed by the dynamic taint analyzer;then, with the runtime information provided by its dynamic counterpart, the static taint analyzer can process the unexecuted part of the target program easily. Furthermore, a taint behavior filtration mechanism is proposed to optimize the performance of the framework. We evaluate our framework from three perspectives: efficiency, coverage, and effectiveness, and the results are encouraging. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Static analysis

来源：评论

学校读者我要写书评

暂无评论

Using minimum mobile chargers to keep large-scale wireless rechargeable sensor networks running forever

Using minimum mobile chargers to keep large-scale wireless r...

引用

2013 IEEE 2013 22nd International Conference on Computer Communication and Networks, ICCCN 2013

作者： Dai, Haipeng Wu, Xiaobing Xu, Lijie Chen, Guihai Lin, Shan State Key Laboratory for Novel Software Technology Nanjing University Nanjing Jiansu 210046 China Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai 200240 China Temple University Philadelphia PA United States

ISBN: (纸本)9781467357746

Wireless Rechargeable Sensor Networks (WRSNs) can be recharged after deployment for sustainable operations. Recent works propose to use a single mobile charger (MC) traveling through the network fields to recharge every sensor node. These algorithms work well in small scale networks. However, in large scale networks these algorithms do not work efficiently, especially when the amount of energy the MC can provide is limited. To address these challenges, multiple MCs can be used. In this paper, we investigate the minimum MCs problem (MinMCP) for rechargeable sensor networks: how to find the minimum number of energy-constrained MCs and design their recharging routes given a sensor network such that each sensor node in the WRSN maintains continuous work. Our results are three folds. We first prove that for any Ε > 0, there is no (2-Ε)-approximation algorithm for Distance Constrained Vehicle Routing Problem (DVRP) on a general metric space, which is the best as far as we know. By reducing from DVRP, we prove that MinMCP is NP-hard, and the inapproximability bound for MinMCP is the same as that of DVRP. Then we propose approximation algorithms for this problem. Finally, we conduct simulations to validate the effectiveness of our algorithms. © 2013 IEEE.

关键词： Approximation algorithms

来源：评论

学校读者我要写书评

暂无评论

VGRIS: Virtualized GPU resource isolation and scheduling in cloud gaming

VGRIS: Virtualized GPU resource isolation and scheduling in ...

引用

22nd ACM International Symposium on High-Performance Parallel and Distributed computing, HPDC 2013

作者： Yu, Miao Zhang, Chao Qi, Zhengwei Yao, Jianguo Wang, Yin Guan, Haibing School of Software Shanghai Jiao Tong University Shanghai China HP Labs. Palo Alto CA United States Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai China Cylab Carnegie Mellon University United States

ISBN: (纸本)9781450319102

Fueled by the maturity of virtualization technology for Graphics Processing Unit (GPU), there is an increasing number of data centers dedicated to GPU-related computation tasks in cloud gaming. However, GPU resource sharing in these applications is usually poor. This stems from the fact that the typical cloud gaming service providers often allocate one GPU exclusively for one game. To achieve the efficiency of computational resource management, there is a demand for cloud computing to employ the multi-task scheduling technologies to improve the utilization of GPU. In this paper, we propose VGRIS, a resource management framework for Virtualized GPU Resource Isolation and Scheduling in cloud gaming. By leveraging the mature GPU paravirtualization architecture, VGRIS resides in the host through library API interception, while the guest OS and the GPU computing applications remain unmodified. In the proposed framework, we implemented three scheduling algorithms in VGRIS for different objectives, i.e., Service Level Agreement (SLA)-aware scheduling, proportional-share scheduling, and hybrid scheduling that mixes the former two. By designing such a scheduling framework, it is possible to handle different kinds of GPU computation tasks for different purposes in cloud gaming. Our experimental results show that each scheduling algorithm can achieve its goals under various workloads. © 2013 ACM.

关键词： Graphics processing unit

来源：评论

学校读者我要写书评

暂无评论

STAMP: A Strategy-Proof Approximation Auction Mechanism for Spatially Reusable Items in Wireless Networks

STAMP: A Strategy-Proof Approximation Auction Mechanism for ...

引用

IEEE Global Communications Conference

作者： Ruihao Zhu Fan Wu Guihai Chen Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University China

ISBN: (纸本)9781479913510

The advent of participatory sensing markets and spectrum markets based on the wireless networks have led to a new kind of auction dealing with spatially reusable items, which can be shared by multiple parties that are geographically far apart enough from each other. Simply applying traditional auctions to spatially reusable items is vulnerable to bid manipulation, and may lead to low allocation efficiency. In this paper, we study the problem of auctioning spatially reusable items. We propose STAMP, which is a STrategy-proof Approximation auction Mechanism for sPatially reusable items in wireless networks. STAMP can be implemented with any existing maximum independent set algorithm, and can guarantee the allocation efficiency as high as the algorithm based on. Evaluation results show that STAMP achieves much better performance than existing mechanisms, in terms of allocation efficiency.

关键词： advent wireless networks STAMP stamp Wireless networks Reusable

来源：评论

学校读者我要写书评

暂无评论

SRIDesk: A Streaming based Remote Interactivity architecture for desktop virtualization system

SRIDesk: A Streaming based Remote Interactivity architecture...

引用

IEEE Symposium on Computers and Communications (ISCC)

作者： Jiewei Wu Jiajun Wang Zhengwei Qi Haibing Guan Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai China

ISBN: (纸本)9781479937561

In recent years, desktop virtualization trends to be a new extension of virtualization framework. The existing desktop virtualization systems suffer performance degradation in terms of response time and video quality. However, previous remote access approaches are designed for standalone architectures and require semantic information which is not transparent to OS. So they are not feasible in desktop virtualization systems. In this paper, we propose SRIDesk, a Streaming based Remote Interactivity architecture for Desktop virtualization system. SRIDesk resides in the host through intercepting virtual display device, which is transparent to guest OS and its applications. SRIDesk integrates server-push streaming mechanism with H.264 encoder into virtualization system, which provides high quality display with low bandwidth consumption and low latency of interaction. We have implemented the SRIDesk prototype in a KVM system. Experimental results show that SRIDesk has low CPU-load, low bandwidth and good scalability. We compared SRIDesk with other popular platforms, including X, VNC, RDP and THiNC. SRIDesk outperformed other systems in bandwidth with no more than 2Mbps and 94% video quality. SRIDesk also achieved lowest latency in WAN environment among all systems.

关键词： Linux Local area networks Wide area networks Virtual machining Servers Protocols

来源：评论

学校读者我要写书评

暂无评论

An energy-efficient and scalable eDRAM-based register file architecture for GPGPU 13

An energy-efficient and scalable eDRAM-based register file a...

引用

40th Annual International Symposium on Computer Architecture, ISCA 2013

作者： Jing, Naifeng Shen, Yao Lu, Yao Ganapathy, Shrikanth Mao, Zhigang Guo, Minyi Canal, Ramon Liang, Xiaoyao Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai China Shanghai Key Laboratory of Scalable Computing and Systems Shanghai Jiao Tong University Shanghai China School of Microelectronics Shanghai Jiao Tong University Shanghai China Universitat Politecnica de Catalunya Barcelona Spain

ISBN: (纸本)9781450320795

The heavily-threaded data processing demands of streaming multiprocessors (SM) in a GPGPU require a large register file (RF). The fast increasing size of the RF makes the area cost and power consumption unaffordable for traditional SRAM designs in the future technologies. In this paper, we propose to use embedded-DRAM (eDRAM) as an alternative in future GPGPUs. Compared with SRAM, eDRAM provides higher density and lower leakage power. However, the limited data retention time in eDRAM poses new challenges. Periodic refresh operations are needed to maintain data integrity. This is exacerbated with the scaling of eDRAM density, process variations and temperature. Unlike conventional CPUs which make use of multi-ported RF, most of the RFs in modern GPGPU are heavily banked but not multi-ported to reduce the hardware cost. This provides a unique opportunity to hide the refresh overhead. We propose two different eDRAM implementations based on 3T1D and 1T1C memory cells. To mitigate the impact of periodic refresh, we propose two novel refresh solutions using bank bubble and bank walk-through. Plus, for the 1T1C RF, we design an interleaved bank organization together with an intelligent warp scheduling strategy to reduce the impact of the destructive reads. The analysis shows that our schemes present better energy efficiency, scalability and variation tolerance than traditional SRAM-based designs. Copyright 2013 ACM.

关键词： Static random access storage

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：