排序方式: 共有9条查询结果,搜索用时 500 毫秒
1
1.
2.
This article provides an overview of current research on Fragile X Syndrome, and how that knowledge can be used to guide successful intervention. The genetic etiology of Fragile X is reviewed and the physical, cognitive, adaptive, behavioral, and emotional phenotypes of children with the disorder are described, highlighting the differences in presentation among males and females. Comorbidity with autism is addressed. Typical strengths and weaknesses of children with Fragile X are delineated as a basis for educational assessment and intervention. A multidisciplinary approach to treatment is advocated, including medical management, educational accommodations, and speech-language and occupational therapy. The social and emotional challenges of those with the syndrome are considered in recommended interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Schwarte H. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1996,42(5):1549-1551
The relationship between weak convergence of channel probability measures, channel capacity, and error probability of block codes is examined for memoryless channels with general input and output alphabets. It is shown that channel capacity is a lower semi-continuous function and that every block code with maximal probability of error δ for a nominal channel for any ϵ>0 can be modified such that the modification has a probability of error less than δ+ϵ for all channels in a sufficiently small neighborhood of the nominal channel 相似文献
4.
During the past five years the Institute of Construction Materials at the University of Stuttgart (IWB) has participated in
different projects concerning e-teaching. Amongst other efforts co-workers of IWB have created a set of virtual content concerning
concrete technology within a German e-teaching network in civil engineering materials science called “WiBA-Net” (). The content of this network consists of teaching material that is organized at four different levels of granularity. At
the most basic level single items (“assets”) are collected. At the second level such assets are arranged into single pages
filling one screen. Several pages dealing with aspects of a single topic are ordered into a teaching path at the third level
and finally a set of teaching paths forms an entire course at level four. Virtual searching methods are offered on all four
levels depending on the state of the user. Besides the mentioned teaching material also virtual communication facilities are
offered within the network. During the work on WiBA-Net, which consists of six German Universities, questions concerning the
reusability of virtual content, metadata enhancement techniques and the concept of Blended Learning were focused. Educational
and didactic aspects have been closely taken into account and quality assuring evaluation methods have been applied.
Meanwhile first experiences have been made in real life teaching and learning situations, which give us an idea of future
needs and development in the field. 相似文献
5.
Gulden P. Vossiek M. Heide P. Schwarte R. 《IEEE transactions on instrumentation and measurement》2002,51(4):679-684
The novel photoelectronic mixing device (PMD) possesses a variety of unique characteristics that open up new fields for optical distance measurement technology. PMD devices for the first time allow the use of straightforward modulation and system concepts previously constrained to radar and ultrasonic systems. This paper first reviews the PMD principle and then points out the differences between conventional optical systems and PMD systems. The requirements of two different applications, level gauging, and three-dimensional object position measurement are discussed. Suitable system concepts are introduced and verified with experiments. The results prove the feasibility of single-pixel sensors capable of high accuracy and multitarget resolution as well as low-cost three-dimensional imaging systems. 相似文献
6.
Christoph Heise Stefan Böhm Stefan Schwarte Hans-Jürgen Roscher Burkhard Kranz 《Production Engineering》2014,8(5):567-575
Hybrid technologies offer an important approach to enhance existing limits of conventional cutting manufacturing processes. Superposition of the infeed with adapted ultrasonic vibrations enables reductions of machining forces. This results in diminished tool wear and longer tool life. Furthermore, an increase of removal rates can be achieved. Successful machining of recalcitrant metal-based materials by ultrasonic assisted systems creates a high potential to gain similar effects in machining of mineral-based materials. This will be studied in this article. The state of the art for the machining of stone uses geometrically undefined cutting edges. This paper focuses on the geometrically defined cutting of granite with additional ultrasonic assistance. Cutting tests at a test station with linear cutting motion are being performed. The ultrasonic frequency is maintained at 20 kHz. Different oscillation amplitudes are applied to influence process forces and the wear of the used carbide metal and polycrystalline diamond cutting segments (PCD). A method to observe the wear is developed by use of a stereomicroscope and a 3D measurement system. This will enable conclusions about the applicability of the geometry of the cutting segments and the process parameters. Due to the significant different wear rates of both cutting materials, the cutting force progression by using PCD tools shows completely different characteristics compared to the machining with carbide metal tools. 相似文献
7.
DB Spangenberg E Coccaro R Schwarte B Lowe 《Canadian Metallurgical Quarterly》1996,10(3):875-87; discussion 887-8
Ultrastructural studies of the statocysts and touch-plates of graviceptors (rhopalia) of Aurelia ephyrae revealed that (1) touch-plate hair cells are present; and (2) cytoplasmic strands from the hair cell bases extend from the neurite plexus to touch similar strands from the lithocytes. This close association of hair cell neurites and statocysts may have important implications regarding the transmitting and processing of positional information with respect to the gravity vector. Graviceptors of ephyrae which developed while weightless in microgravity were compared with controls at the ultrastructural level. We found that hair cells of ephyrae which developed in microgravity had fewer lipid droplets in the large spaces near their bases as compared with 1 g controls. In the ephyrae from the first microgravity experiment, hair cells had more large apical vacuoles with filamentous content than were found in hair cells of ephyrae from the second experiment and controls. The neurite plexus and the network of cytoplasmic strands extending to the statocysts were not different in microgravity-developed ephyrae from controls. Behavioral differences in swimming and orienting in ephyrae in microgravity and controls (reported earlier) were not explained by morphological differences in the hair cells of the touch-plates or the statocysts, although functional differences apparently occurred. 相似文献
8.
A special sampling system has been designed and constructed to record pulse-shape information of extremely fast singly occurring events at low energy levels. The new instrument delivers 40 amplitude values from a single-shot pulse, with risetimes down to 100 ps and an absolute sensitivity of only a few millivolts. 相似文献
9.
Design of an aspherical lens to generate a homogenous irradiance for three-dimensional sensors with a light-emitting-diode source 总被引:2,自引:0,他引:2
A design of a large-numerical-aperture aspherical singlet for three-dimensional (3-D) sensor applications is presented. This lens can be used to generate a homogenous irradiance on the target in a 3-D sensor, which is based on the principle of time of flight and uses an LED as light source. A numerical method was used in the design. The designed planoaspherical singlet has a numerical aperture of 0.67, low refractive index, and moderate surface shape for easy fabrication. The simulation results revealed that the irradiance deviation within 97% of the designed area is less than 5% and that the transmittance of the lens is greater than 90.5%. The results from a Lambertian source were compared with those from a point source. 相似文献
1