检索结果-内蒙古大学图书馆

IEEE Photonics Conference (IPC)

作者： S. Krishna P. Bhattacharya J. Singh J. Urayama T.B. Norris P.J. McCann K. Namjou Applied Physics Program Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA School of Electrical and Computer Engineering University of Oklahama Norman OK USA

Summary form only given. We report the room temperature operation of a novel unipolar self-organized quantum dot FIR laser (13.3 /spl mu/m) based on transitions between discrete bound electron states in self-organized... 详细信息

关键词： Quantum dot lasers US Department of Transportation Electrons Infrared detectors Stationary state Finite impulse response filter Land surface temperature Infrared spectra Spectroscopy Laser radar

来源：评论

学校读者我要写书评

暂无评论

On the Perception of Transients: Applying Psychophysical Constraints to Improve Audio Analysis and Synthesis 26

On the Perception of Transients: Applying Psychophysical Con...

引用

26th International computer Music Conference, ICMC 2000

作者： Wakefield, Gregory H. Heller, Laurie M. Carney, Laurel H. Mellody, Maureen Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI48109 United States Naval Submarine Medical Research Laboratory GrotonCT06359 United States Hearing Research Center Dept. of Biomedical Engineering Boston University BostonMA02215 United States Applied Physics Program University of Michigan United States

In a psychophysical experiment, a wideband, 4-ms noise is compared with spectrally smoothed versions of the noise. To isolate on the magnitude spectrum, the phase spectrum is controlled by assigning the same random phase spectrum to both the original and smoothed signals. Depending on the choice of phase spectrum, discrimination thresholds for spectral shape vary from a maximum spectral deviation of 2-3 dB to as much as 25 dB. The exact source of this effect remains an open question. However, it suggests that not all transients require the same signal fidelity. Given a proper characterization of the perceptual response, it may be possible to reduce the size of the codebook required to maintain acceptable perceptual results. © 2000 ICMC. All Rights Reserved.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Polarization effects and transport in AlGaN/GaN system

Journal of Vacuum Science & Technology B: Microelectronics a...

引用

Journal of Vacuum science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 2000年第4期18卷 2322-2327页

作者： Yifei Zhang Yulia Smorchkova C. Elsass Stacia Keller James Ibbetson Steven DenBaars Umesh Mishra Jasprit Singh Applied Physics Program University of Michigan Ann Arbor Michigan 48109 Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor Michigan 48109-2122 Department of Electrical and Computer Engineering University of California Santa Barbara California 93106 Department of Electrical Engineering and Computer Engineering University of Michigan Ann Arbor Michigan 48109

The AlGaN/GaN heterostructure is important for both electronic and optoelectronic devices. In addition to having a large band gap, the heterostructure has a strong piezoelectric effect and a large spontaneous polarization. This allows one to incorporate a large electric field (>106 V/cm) and high sheet charge (>1013 cm−2) without doping. Theoretical studies are done to examine how polarization effects controls the sheet charge density. The studies also focus on how interface roughness, aluminum mole fraction in the barrier, impurity scattering, sheet charge density, and phonon scattering influence mobility. Results are compared with experimental studies on samples grown by both molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD). We find that interface roughness is a dominant source of scattering in the samples reported. Due to the variation in growth techniques we find that the MBE samples have a smoother interface quality compared to the MOCVD samples. By carefully fitting the experimental data we present results on interface roughness parameters for MBE and MOCVD samples.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Biophysical and spectral characteristics of cool- and warm-season grasslands under three land management practices in Eastern Kansas

引用

Natural Resources Research 2000年第4期9卷 321-331页

作者： Guo, Xulin Price, Kevin P. Stiles, James M. Kansas Applied Remote Sensing Program (KARS) Department of Geography University of Kansas Lawrence KS 66045 2335 Irving Hill Road United States Radar Systems and Remote Sensing Laboratory (RSL) Department of Electrical Engineering and Computer Science University of Kansas Lawrence KS 66045 2335 Irving Hill Road United States Lawrence KS 66045 2335 Irving Hill Road United States

Grasslands are the largest of the Earth's four major vegetation types and are among the most agriculturally productive lands. Grassland management practices alter biophysical factors, such as plant species composition, soil structure and chemistry, and primary productivity. Large-scale changes in land management practices can have significant impacts on available natural resources, therefore impacting a regional socioeconomics. For these reasons, an improved understanding of the geographic distribution of changing land management practices and how these changes affect grassland biophysical characteristics of an area is critical to improve land use planning and practices. This study investigated the spectral characteristics, as measured using satellite remotely sensed data, of three land management practices [grazing, haying, and management under Conservation Reserve program (CRP)] on areas dominated by cool- and warm-season grasslands. The satellite imagery was acquired in May, July, and September in 1997 over Douglas County, Kansas. Biomass, vegetation cover, and species richness data were collected around the satellite overflight periods. Our results indicate that the biophysical characteristics and spectral reflectances are significantly different among the three management practices over cool- and warm-season grasslands. Interestingly, sites grazed by livestock had the highest species richness and the highest forb cover, although the total cover is almost the same as the other practices, and they have the highest near-infrared reflectance throughout the growing season. © 2000 International Association for Mathematical Geology.

关键词： Landsat Tallgrass prairie Thematic Mapper (TM)

来源：评论

学校读者我要写书评

暂无评论

A lower bound on the complexity of approximate nearest-neighbor searching on the Hamming cube 99

A lower bound on the complexity of approximate nearest-neigh...

引用

Proceedings of the thirty-first annual ACM symposium on Theory of Computing

作者： Amit Chakrabarti Bernard Chazelle Benjamin Gum Alexey Lvov Department of Computer Science Princeton University Department of Computer Science Princeton University and NEC Research Institute Program in Applied and Computational Mathematics Princeton University

来源：评论

学校读者我要写书评

暂无评论

Synthetic cultures: Intercultural learning through simulation games

引用

Simulation and Gaming 1999年第4期30卷 415-440页

作者： Hofstede, Gert Jan Pedersen, Paul Wageningen University Applied Computer Science Group 6703 HB Wageningen Dreijenplein 2 Netherlands University of Alabama at Birmingham Department of Human Studies Counseling Program School of Education Birmingham AL 35294-1250 157 Education Building 901 south 193th street United States

This article introduces the concept of synthetic cultures. These are role profiles for enacting dimensions of national culture. The full profiles are given for 10 synthetic cultures, based on Gert Hofstede's dimensions of national culture. They can be used for training or simulation/gaming. Examples of their application are presented. Apart from examples of existing games, suggestions are made for creating custom simulations that use synthetic cultures. Experiences of players are mentioned, both in face-to-face and in electronically mediated settings. Special attention is paid to debriefing issues. The article concludes with practical advice to prospective game leaders. © 1999 Sage Publications, Inc.

关键词： Business game Culture clash Electronic communication Intercultural learning National culture Role profile Simulation game Synthetic culture

来源：评论

学校读者我要写书评

暂无评论

A HIGH-RESOLUTION TIME-FREQUENCY ANALYSIS OF THE SINGING VOICE

A HIGH-RESOLUTION TIME-FREQUENCY ANALYSIS OF THE SINGING VOI...

引用

1999 International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 1999

作者： Mellody, Maureen Wakefield, Gregory H. Applied Physics Program 500 East University Dr. Ann ArborMI48109-1120 United States Department of Electrical Engineering and Computer Science University of Michigan 1301 Beat Ave. Ann ArborMI48109-2122 United States

We apply the modal distribution, a high-resolution time-frequency distribution, to the study of sung musical passages. Evidence is presented comparing the modal distribution with the spectrogram for a set of synthetic signals which emulate human singing. We then compare the two techniques for sung passages from four student sopranos with respect to measures of the instantaneous frequency and amplitude of the partials. In general, the modal distribution appears to be a more sensitive measure of individual differences in vocal production than the spectrogram. © 1999 Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 1999. All rights reserved.

关键词： Modal analysis

来源：评论

学校读者我要写书评

暂无评论

Definition of evaluation criteria for system development acquisition modeling and simulation

引用

NAVAL ENGINEERS JOURNAL 1999年第1期111卷 55-64页

作者： Leite, MJ Mensh, DR Michael J. Leite:is a Principal Engineer with PRC Inc. a division of Litton Industries. He supports combat system engineering for theater air and missile defense. His other tasks have included the command and control for the AEGIS shipbuilding program systems engineering for the 21st Century Surface Combatant combat system survivability and the development of NATO standardization agreements for naval ordnance. He was previously a Senior Engineer with San Diego Gas & Electric with responsibility for its energy application and lighting programs. Prior to joining SDG&E Mr. Leite was a commissioned officer in the U.S. Navy where he served in operations and engineering assignments. Following active duty he accepted a Naval Reserve commission and has retired with the rank of Captain. His assignments included command operational and engineering tours. Mr. Leite has also served as an expert witness in admiralty and engineering matters. He is a gradate of the University of California Berkeley with a Bachelor of Science Degree in Engineering and also holds a Masters Degree in Business Administration from National University in San Diego. Mr. Leite is a Registered Professional Engineer in the States of California and Minnesota. Mr. Leite is a member of ASNE ASCE MORS the Illuminating Engineering Society and the U.S. Naval institute. Dennis Roy Mensh:is a Senior Engineer with PRC Inc. a division of Litton Industries in Crystal City VA where he supports modeling and simulation tasking for combat systems. He received BS and MS degrees in applied Physics from Lopola College in Baltimore MD and the American University in Washington DC. He has also completed the course work towards a Ph.D. degree in computer science specializing in the fields of Operations Reseurch Anabsis Systems Analysis and Computer Modeling and Simulation. Previously he was employed at the White Oak Laboratory of the Naval Surface Warfare Carter in Silver Spring MD where he worked in the areas of naval sensor and weapon system analysis

This paper defines, develops and examines a set of generic analysis tools that can be applied to Models and Simulations at the Systems Engineering level of fidelity. The tools examine the performance and effectiveness of Sensors;Weapons;and Battle Management, Command, Control, Communications, computers, and Intelligence ((BMCI)-I-4) systems and equipment. The Measures of Performance (MOPs), Measures of Effectiveness (MOEs) and Measures of Force Effectiveness (MOFEs) were extracted from the Modular Command and Control Structure Paradigm which was developed at the Naval Postgraduate School. The paradigm provides for the development of evaluation criteria (MOPs, MOEs, and MOFEs) in a framework that ensures the traceability of system performance and effectiveness to the system operational requirements as specified in the Operational Requirements Document (ORD). Also, the analysis tools provide insight and valid estimates of numerical measures of the defined system functionality threads, which represent the system's operational requirements as specified in the ORD. The tools are directly transferrable and applicable to test and evaluation exercise events which are conducted in support of the development and acquisition of systems and equipment. Once the levels of system performance have been defined, the Paradigm generates a quantitative database that becomes a useful tool in system tradeoffs and selection. Once the alternative system suites have been defined, the suites can be analyzed in terms of system functionality threads and their corresponding performance capabilities versus cost.

关键词： Naval vessels

来源：评论

学校读者我要写书评

暂无评论

Applying fuzzy functions and sequential coordination to optimization of machinery arrangement and pipe routing

引用

NAVAL ENGINEERS JOURNAL 1998年第6期110卷 43-54页

作者： Wu, BC Young, GS Schmidt, W Choppella, K Dr. Bi-Chu Wu:received a PhD in Mechanical Engineering from the University of Maryland College Park in 1991. She has worked on projects involving naval architecture design optimization solid mechanics and database development. Presently a senwr engineer with Angle Incorporated Dr Wu's research interests are in design optimization and fuzzy logic applications. Dr. Gin-Shu Young: a senior engineer with Angle Incorporated holds a PhD in Mechanical Engineering from the University of Maryland College Park. As a guest researcher with National Institute of Standards and Technologies from 1990 to 1993 he worked on vision-based navigation for autonomous vehicles. His experience also includes applications of optimization fuzzy logic neural network and genetic algorithm methods to engineering system design Mr. William Schmidt:co-founded Angle Incorporated in 1990 and has served as Vice PresidentlChiefScientist during this tame. He holds a B.Sc. in Applied Science from the Naval Acadt?my and an M.Sc. in Physics from the Naval Post Graduate School. He has cner 20 years experience in technical leadership material and personnel management. He has led the application of computer aided design (CAD) and Product Model Information Exchange to the shipbuilding industry. His experience also includes leading the amlication of model based operational analysis to support the Live Fire Test Program for DDG 51 Class Destroyers. Mr. Krishna M. Choppella:is a Sofware Engineer at Eidea Laboratories Incotporated where he works on componentbased distributed enterpvise frameworks. He has been involved in creating data analysis tools for the US Nay by integrating CAD modeis databases and graphical front ends. His work in the Masters degree program in Mechanical Engineering at the University of Texas at Austin was in di0ddase.r spectroscopy of combustion products in porous-matri burners. He received his Bachelors degree in Electrical Engineering in India. He was a Research Associate at the Centre for Laser Technology and Project Engi

Ship design is often multidisciplinary involving several design elements with various types of objectives and constraints (O/C) some easily described as mathematical formulas, others better modeled as descriptive assertions. This paper describes a method based on fuzzy functions and an integrated performance index to model O/C using descriptive assertions to be used with mathematical formulas in optimization. Another issue addressed in this paper concerns the coordination of design elements when sequentially coupled, that is, when one leads the other and the performance of the follower depends greatly on the design of the leader. Based on neuro-fuzzy techniques, the method described here coordinates and optimizes sequentially coupled elements. The two methods are applied to machinery arrangement (MA) and pipe routing (PR). Preliminary models for optimization of MA and PR are described considering convenience, producibility: engine room size, interference and location as factors in the O/C set. Some test results from MA/PR applications are presented and discussed. The methods are generic and can be extended to other elements in ship design. They are mutually independent and may be used separately Two advantages of their use are an improvement in overall performance and a reduction in the need for redesign of elements.

关键词： Optimization

来源：评论

学校读者我要写书评

暂无评论

A Modal Distribution Study of Violin Vibrato 23

A Modal Distribution Study of Violin Vibrato

引用

23rd International computer Music Conference, ICMC 1997

作者： Mellody, Maureen Wakefield, Gregory H. Applied Physics Program University of Michigan United States Department of Electrical Engineering and Computer Science University of Michigan United States

A high-resolution time-frequency distribution is applied to the study of violin vibrato. Our analysis indicates that the frequency modulation induced by the motion of the stopped finger on the string is accompanied by a significant amplitude variation in each partial of that note. We suggest that this amplitude modulation results from the densely-spaced wood resonances of the violin body. Amplitude and frequency estimates for each partial are extracted from the time-frequency surface and used in an additive resynthesis model to generate synthesized violin vibrato. © 1997 International computer Music Conference, ICMC Proceedings. All rights reserved.

关键词： computer music

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：