检索结果-内蒙古大学图书馆

Dual-Wavelength Bad Cavity Laser as Potential Active Optical Frequency Standard

Chinese Physics Letters 2015年第9期32卷 31-34页

作者：许志超潘多庄伟陈景标 State Key Laboratory of Advanced Optical Communication System and Network Institute of Quantum Electronics School of Electronics Engineering & Computer Science Peking University Beijing 100871 National Institute of Metrology Beijing 100013

We experimentally realize the dual-wavelength bad cavity laser for the first time. As the Cs cell temperature is kept between 118℃ and 144℃, both the 1359nm and 147Ohm lasing outputs of dual-wavelength bad cavity laser are detected. The laser output power of dual-wavelength bad cavity laser is measured when changing the 455 nm pumping laser frequency and power at 127℃ Cs cell temperature. Both the 1359 nm laser and the 1470 nm laser are working at the deep bad cavity regime, and the ratio between the linewidth of cavity mode and the laser gain bandwidth a ≈ 40 for 1359nm and 1470nm lasers. The 147Ohm laser linewidth is measured to be 407.3Hz. The dual-wavelength bad cavity laser operating on atomic transitions demonstrated here has a potential in the application as a stable optical local oscillator, even an active optical frequency standard directly in the future.

关键词： Dual-Wavelength Bad Cavity Laser as Potential Active Optical Frequency Standard As Cs length

来源：评论

学校读者我要写书评

暂无评论

Dynamic event-triggered formation control of second-order nonholonomic systems

引用

Journal of systems Engineering and Electronics 2023年第2期34卷 501-514页

作者： WANG Xiaoyu SUN Sijia XIAO Feng YU Mei School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

In this paper,the formation control problem of secondorder nonholonomic mobile robot systems is investigated in a dynamic event-triggered ***-triggered control protocols combined with persistent excitation(PE)conditions are *** event-detecting processes,an inactive time is introduced after each sampling instant,which can ensure a positive minimum sampling *** increase the flexibility of the event-triggered scheme,internal dynamic variables are included in event-triggering ***,the dynamic event-triggered scheme plays an important role in increasing the lengths of time intervals between any two consecutive *** addition,event-triggered control protocols without forward and angular velocities are also presented based on approximate-differentiation(low-pass)*** asymptotic convergence results are given based on a nested Matrosov theorem and artificial sampling methods.

关键词： nonholonomic system dynamic event-triggered control consensus-based formation

来源：评论

学校读者我要写书评

暂无评论

Profile guided optimization for dataflow predication

Profile guided optimization for dataflow predication

引用

13th IEEE Asia-Pacific computer systems architecture Conference, ACSAC 2008

作者： Li, Wang Hong, An Yongqing, Ren Yaobin, Wang Department of Computer Science and Technology University of Science and Technology of China Hefei 230026 China Key Laboratory of Computer System and Architecture Chinese Academy of Sciences Beijing 100080 China

ISBN: (纸本)9781424426836

Dataflow predication provides a lightweight full support for predicated execution in dataflow-like architectures. One of its major overhead is the large amounts of fanout trees for distributing predicates to all dependant instructions. Conventional optimizations are predicating only the heads or tails of dataflow chains. Predicating tails offers more speculation but leads to resource contentions and power consumption increasing. Predicating heads is power efficient but reduces speculation and instruction level parallelism. This paper introduces a profile guided technique to combine these optimizations. It uses profiling feedback to guide the compiler in deciding to predicate at the head or tail. By predicating tails on hot paths and predicating heads on infrequent paths, this technique can get performance, power and resource efficiency Performance evaluation result shows that profile guided optimization performs better in removing fanout trees. It has 10.6% speedup over always predicating heads and 2.5% speedup over always predicating tails in performance. © 2008 IEEE.

关键词： Forestry

来源：评论

学校读者我要写书评

暂无评论

Resource allocation scheme based on weighted power control in cognitive radio systems

Resource allocation scheme based on weighted power control i...

引用

2013 International Conference on Communications, Circuits and systems, ICCCAS 2013

作者： Li, Jingye Luo, Tao Yue, Guangxin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China State Key Laboratory of Integrated Services Networks Xidian University Xi'an China

ISBN: (纸本)9781479930517

Opportunistic spectrum access (OSA) is a promising method to improve the spectrum utilization. In this paper, we propose a weighted power control approach to further exploit the flexibility of OSA. We first give the definition and basic idea of confidence level of sub-channel idle (CLSI), then two schemes are raised to enhance the system performance considering the time-variance of channels, the accuracy of spectrum sensing and mutual interference (MI) in power-constrained cognitive radio systems. The first scheme is to maximize the system capacity, and the second one is a multi-objective optimization model for maximizing both the system capacity and the user satisfaction. Both theoretical analysis and simulation results demonstrate that scheme 1 can achieve optimal system capacity, and scheme 2 can obtain sub-optimal system capacity with optimal user satisfaction compared to the conventional algorithm. © 2013 IEEE.

关键词： Optimal systems

来源：评论

学校读者我要写书评

暂无评论

CuHMMer: A load-balanced CPU-GPU cooperative bioinformatics application

CuHMMer: A load-balanced CPU-GPU cooperative bioinformatics ...

引用

2010 International Conference on High Performance Computing and Simulation, HPCS 2010

作者： Yao, Ping An, Hong Xu, Mu Liu, Gu Li, Xiaoqiang Wang, Yaobin Han, Wenting School of Computer Science and Technology University of Science and Technology of China Hefei 230027 China Key Laboratory of Computer System and Architecture Chinese Academy of Sciences Beijing 100080 China

ISBN: (纸本)9781424468287

GPUs have recently been used to accelerate data-parallel applications for they provide easier programmability and increased generality while maintaining the tremendous memory bandwidth and computational power. Most of those applications use CPU as a controller who decides when GPUs run the computing-intensive tasks. This CPU-control-GPU-compute pattern wastes much of CPU's computational power. In this paper, we present a new CPU-GPU cooperative pattern for bioinformatics applications which can use both of CPU and GPU to compute. This pattern includes two parts: 1) the load-balanced data structure which manages data to keep the computational efficiency of GPU high enough when the length distribution of sequences in a sequence database is very uneven;2) multi-threaded code partition which schedules computing on CPU and GPU in a cooperative way. Using this pattern, we develop CuHMMer based on HMMER which is one of the most important algorithms in bioinformatics. The experimental result demonstrates that CuHMMer get 13x to 45x speed up over available CPU implementations and could also outperform the traditional CUDA implementations which use CPU-control-GPU-compute pattern. ©2010 IEEE.

关键词： Graphics processing unit

来源：评论

学校读者我要写书评

暂无评论

A Wire delay scalable stream processor architecture

A Wire delay scalable stream processor architecture

引用

13th IEEE Asia-Pacific computer systems architecture Conference, ACSAC 2008

作者： Guang, Xu Hong, An Ming, Cong Fang, Wang Yongqing, Ren Department of Computer Science and Technology University of Science and Technology of China Hefei 230026 China Key Laboratory of Computer System and Architecture Chinese Academy of Science Beijing 100080 China

ISBN: (纸本)9781424426836

Growing on-chip wire delays will cause many future microarchitecture to be distributed. The centralized control and data transmission of the conventional stream processor need to be improved, the hardware resources within a single stream processor become tiles on one or more switched micronetworks. In this paper, we introduce the architecture of the tiled stream processor which aims to adapt to the increasing wire resistance. The tiled stream processor consists of tile arrays, the distributed control and data network which connect tiles. The tile arrays include the five type of reused tiles, the control packet transferred in the control network traverse the tile in a cycle. The architecture of the tiled stream processor supports explicit data management in the hardware way and include two level register hierarchy which are controlled by the software to capture the data locality. The tiled stream processor use the stream programming model which are StreamC/KernelC language, the kernel microcode executed in the tiled arrays are statically scheduled into instruction blocks and execute dynamically in an dataflow order. Finally, we discuss features that affect the kernel performance, with the one cycle routing delay the simulator can achieve an average of 10IPC in eight kernels. © 2008 IEEE.

关键词： computer architecture

来源：评论

学校读者我要写书评

暂无评论

Cacheap:Portable and Collaborative I/O Optimization for Graph Processing

引用

Journal of computer Science & Technology 2019年第3期34卷 690-706页

作者： Peng Zhao Chen Ding Lei Liu Jiping Yu Wentao Han Xiao-Bing Feng State Key Laboratory of Computer Architecture Institute of Computing TechnologyChinese Academy of Sciences Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Computer Science University of RochesterRochester 14623U.S.A. Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

Increasingly there is a need to process graphs that are larger than the available memory on today's *** systems have been developed with grapli representations that are efficient and compact for out-of-core processing.A necessary task in these systems is memory *** paper presents a system called Cacheap which automatically and efficiently manages the available memory to maximize the speed of grapli processing,minimize the amount of disk access,and maximize the utilization of memory for graph *** has a simple interface that can be easily adopted by existing graph *** paper describes the new system,uses it in recent graph engines,and demonstrates its integer factor improvements in the speed of large-scale grapli processing.

关键词： out-of-core graph processing system I/O optimization memory cache graph analytics locality

来源：评论

学校读者我要写书评

暂无评论

Investigation on VRF system Operation Performance in Commercial Buildings Based on Large-Scale Dataset

Investigation on VRF System Operation Performance in Commerc...

引用

2024 ASHRAE Annual Conference

作者： Wu, Yi Xiong, Jianguo Qian, Mingyang Yan, Da The School of Architecture Tsinghua University Beijing China State Key Laboratory of Air-conditioning Equipment and System Energy Conservation Zhuhai China

Cooling energy consumption has become a pivotal issue in the pursuit of sustainable and energy-efficient operation within commercial buildings. With the swift progression of big data technology, access to operational data from cooling systems in these buildings is expanding. This surge in data availability coincides with an increased implementation of Variable Refrigerant Flow (VRF) systems, prompting this study to explore their real-world energy efficiency. Our research delves into the cooling energy demands, operational modes, and other vital performance indicators of VRF systems, aiming to shed light on their actual energy utilization in contemporary building practices. We introduce a comprehensive performance analysis framework that encompasses data collection and purification, examination of key performance metrics, and a detailed comparative analysis against alternative cooling systems. The study includes the gathering and cleaning of operational data from 7,925 VRF units across China, with a focus on crucial performance metrics such as duration of use, cooling load, system load ratio, and energy efficiency. Additionally, the research offers comparisons with residential VRF and water-cooling systems in commercial settings, providing a broad perspective on the HVAC systems' performance in China. The outcomes of this investigation are expected to significantly enhance the selection and management of HVAC systems in commercial buildings, guiding stakeholders toward more informed decisions. Ultimately, this could pave the way for notable energy savings and enhanced operational efficiency through strategic, data-driven approaches. © 2024 ASHRAE.

关键词： HVAC

来源：评论

学校读者我要写书评

暂无评论

Event-Triggered Control for Multi-Agent systems:Event Mechanisms for Information Transmission and Controller Update

引用

Journal of systems Science & Complexity 2022年第3期35卷 953-972页

作者： LIU Pin XIAO Feng WEI Bo State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China

This paper investigates the state consensus of linear multi-agent systems in a graph where each agent is equipped with two novel event-triggering *** agent utilizes them to avoid continuous information transmissions with its neighbors and to reduce the frequencies of controller updates,*** of the event-triggering mechanisms defines a threshold of state errors by a constant plus a state-dependent *** other event-triggering mechanism introduces a period of rest time after each *** each agent,both event-triggering mechanisms are fully distributed and are independent of any global *** authors utilize a co-design approach to deal with the interplay between control gains and parameters in event-triggering *** appropriate control gains in control laws and parameters in event-triggering conditions,subsystems employing discrete-time signals from neighbors and discrete-time signals from their controllers achieve the state *** are performed to illustrate the effectiveness of the proposed event-triggering mechanisms.

关键词： Consensus control event-triggering mechanism multi-agent systems output feedback

来源：评论

学校读者我要写书评

暂无评论

Pragma Directed Shared Memory Centric Optimizations on GPUs

引用

Journal of computer Science & Technology 2016年第2期31卷 235-252页

作者： Jing Li CCF, Lei Liu Yuan Wu Xiang-Hua Liu Yi Gao Xiao-Bing Feng Cheng-YongWu State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Beijing Samsung Telecom Research and Development Center Beijing 100028 China

GPUs become a ubiquitous choice as coprocessors since they have excellent ability in concurrent processing. In GPU architecture, shared memory plays a very important role in system performance as it can largely improve bandwidth utilization and accelerate memory operations. However, even for affine GPU applications that contain regular access patterns, optimizing for shared memory is not an easy work. It often requires programmer expertise and nontrivial parameter selection. Improper shared memory usage might even underutilize GPU resource： Even using state-of-the-art high level programming models （e.g., OpenACC and OpenHMPP）, it is still hard to utilize shared memory since they lack inherent support in describing shared memory optimization and selecting suitable parameters, let alone maintaining high resource utilization. Targeting higher productivity for affine applications, we propose a data centric way to shared memory optimization on GPU. We design a pragma extension on OpenACC so as to convey data management hints of programmers to compiler. Meanwhile, we devise a compiler framework to automatically select optimal parameters for shared arrays, using the polyhedral model. We further propose optimization techniques to expose higher memory and instruction level parallelism. The experimental results show that our shared memory centric approaches effectively improve the performance of five typical GPU applications across four widely used platforms by 3.7x on average, and do not burden programmers with lots of pragmas.

关键词： GPU shared memory pragma directed data centric

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：