Training set design for connected speech recognition

Two methods for generating training sets for a speech recognition system are studied. The first uses a nondeterministic statistical method to generate a uniform distribution of sentences from a finite state machine (FSM) represented in digraph form. The second method, a deterministic heuristic approach, takes into consideration the importance of word ordering to address the problem of coarticulation effects. The two methods are critically compared. The first algorithm, referred to as MARKOV, converts the FSM into a first-order Markov model. The digraphs are determined, transitive closure computed, transition probabilities are assigned, and stopping criteria established. An efficient algorithm for computing these parameters is described. Statistical tests are conducted to verify performance and demonstrate its utility. A second algorithm for generating training sentences, referred to as BIGRAM, uses heuristics to satisfy three requirements: adequate coverage of basic speech (subword) units; adequate coverage of words in the recognition vocabulary (intraword contextual units); and adequate coverage of word pairs bigrams (interword contextual units)     

Virtual prototyping tools for electronic design automation

Virtual prototyping environments are emerging as a new generation of EDA tools. Such a tool will allow the designer to test interactively complex electronic systems on an enhanced-reality virtual workbench, by concurrently running multidomain (mechanical, electrical, thermal, etc.) what-if experiments. Virtual prototyping will shorten the design cycle, improve the product quality, and reduce the time to market. Advanced computational techniques are needed to reduce the execution time, especially for the field (EM and thermal) models used in these virtual prototyping environments. This article shows how neural networks could be used efficiently for 3D EM field modeling. Neural network models have much better real-time performance than classical numerical EM-field modeling methods, and this is particularly important when the field analysis is coupled with system optimization     

Computer-aided design of a BPSK spread-spectrum chip set

The design of a binary-phase shift-keyed (BPSK) spread-spectrum chip set with an integrated CAD environment called VANDA is described. VANDA uses the functional compiler concept to integrate system and physical designs, thus allowing complex high-performance integrated circuit chips to be implemented easily. Three functional compilers have been designed and implemented for the design of a spread-spectrum transceiver: a pseudonoise (PN) generator compiler, a direct digital frequency synthesizer (DDFS) compiler, and a Costas loop compiler. Three test chips for a BPSK digital intermediate frequency (IF) spread-spectrum system generated by these compilers have been fabricated and tested. Details of each of the functional compilers and the test chips are described. In addition, the measurement results for digital IF transceiver test boards constructed using these chips are presented     

大口径反射镜水平集拓扑优化设计

为了设计适用于空间望远镜的具有质量轻、刚度高、高面形精度特点的大尺寸反射镜,提出了基于水平集方法的反射镜拓扑优化设计方法。首先,在口径1 m反射镜镜体初始结构模型的基础上建立有限元模型,基于SIGFIT采用DRESP2建立面形RMS的目标响应函数,将镜面面形精度直接作为目标函数,在重量约束条件下,基于变密度算法与水平集拓扑方法分别进行优化设计,并基于OSSmooth功能对设计结果分离阈值进行研究。通过对优化模型分离阈值进行分析,得到最优化的输出结构模型。采用水平集方法的拓扑优化设计方法的中间密度单元格数目远小于变密度方法,输出结构边界连接性更好。优化模型面形RMS值小于/50（=632.8 nm）,满足设计指标。     

基于B样条辅助虚拟现实室内设计

为了获得理想的虚拟现实室内设计效果,提出基于B样条辅助虚拟现实室内设计方法。首先采用3DMAX建立基本体绘制室内家具模型,利用扩展基本体L-形墙、C-形墙构建个性化墙体,并利用Maya软件设计虚拟现实室内特效;然后以渲染完成的室内模型为前提,采用多视窗交互方法定义曲线以及直线相机路径,设计室内展示动画,利用外部播放器程序播放;最后采用B样条基的形式对虚拟现实室内设计效果进行修复,并加入一阶左导数与右导数相等的约束条件,使得最终效果是表面连续光滑,不会让人产生突兀的感觉,并通过仿真模拟实验验证其性能。结果表明,所提方法可获得理想的虚拟现实室内设计可视化效果,生动地展示了室内设计结构、质感、造型等信息,克服了当前虚拟现实室内设计方法存在的缺陷。     

虚拟现实及增强现实技术在工业设计中的应用

工业设计技术已日益成为产品创新、价值增值过程中重要的手段。由于现有技术支撑手段的局限,传统工业设计过程中反复叠代修改的“设计-快速原形（CAD〉RP）”循环制约了设计师发挥的空间。虚拟现实及增强现实技术的应用可以为设计师提供一个自然、辜观、交互的环境表达设计思想。虽然已有大量的文献描述混合现实技术的进展及其在制造业的应用,但还鲜有专门着重于工业设计这一重要的领域。本文从一个工业设计工程师的角度阐述了混合现实技术在工业设计中的应用,尤其着重于在增强现实环境下的三维空间设计、数字样机和虚拟装配,并与现有的设计方式进行了比较。     

虚拟机和随机调度技术简化无线设计

一种新的无线设计方法使设计师们能将多种基于分组的标准融合到资源受限的手机硬件中.     

舰船导航信号发生器虚拟化设计

介绍了基于PC总线的便携式舰船导航信号发生器虚拟化设计，着重叙述该仪器硬件设计、基于虚拟仪器开发平台LabWindows／CVI的软件设计。     

Virtual MIMO-based cross-layer design for wireless sensor networks

In this paper, a novel multihop virtual multiple-input-multiple-output (MIMO) communication protocol is proposed by the cross-layer design to jointly improve the energy efficiency, reliability, and end-to-end (ETE) QoS provisioning in wireless sensor network (WSN). In the protocol, the traditional low-energy adaptive clustering hierarchy protocol is extended by incorporating the cooperative MIMO communication, multihop routing, and hop-by-hop recovery schemes. Based on the protocol, the overall energy consumption per packet transmission is modeled and the optimal set of transmission parameters is found. Then, the issues of ETE QoS provisioning of the protocol are considered. The ETE latency and throughput of the protocol are modeled in terms of the bit-error-rate (BER) performance of each link. Then, a nonlinear constrained programming model is developed to find the optimal BER performance of each link to meet the ETE QoS requirements with a minimum energy consumption. The particle swarm optimization (PSO) algorithm is employed to solve the problem. Simulation results show the effectiveness of the proposed protocol in energy saving and QoS provisioning.     

Stochastic iterative algorithms for signal set design for Gaussianchannels and optimality of the L2 signal set

We propose a stochastic iteration approach to signal set design. Four practical stochastic iterative algorithms are proposed with respect to equal and average energy constraints and sequential and batch modes. By simulation, a new optimal signal set, the L2 signal set (consisting of a regular simplex set of three signals and some zero signals), is found under the strong simplex conjecture (SSC) condition (equal a priori probability and average energy constraint) at low signal-to-noise ratios (SNR). The optimality of the L1 signal set, the confirmation of the weak simplex conjecture, and two of Dunbridge's (1967) theorems are some of the results obtained by simulations. The influence of SNR and a priori probabilities on the signal sets is also investigated via simulation. As an application to practical communication system design, the signal sets of eight two-dimensional (2-D) signals are studied by simulation under the SSC condition. Two signal sets better than 8-PSK are found. Optimal properties of the L2 signal set are analyzed under the SSC condition at low SNRs. The L2 signal set is proved to be uniquely optimal in 2-D space. The class of signal sets S(M, K) (consisting of a regular simplex set of K signals and M-K zero signals) is analyzed. It is shown that any of the signal sets S(M, K) for 3⩽K⩽M-1 disproves the strong simplex conjecture for M⩾4, and if M⩾7, S(M, 2) (the L1 signal set) also disproves the strong simplex conjecture. It is proved that the L2 signal set is the unique optimal signal set in the class of signal sets S(M, K) for all M⩾4. Several results obtained by Steiner (see ibid., vol.40, no.5, p.721-31, 1994) for all M⩾7 are extended to all M⩾4. Finally, we show that for M⩾7, there exists an integer K'相似文献   

学习型红外遥控装置的研究与设计

红外遥控是一种常用的通信和遥控方法,针时目前各种产品的遥控不能互相兼容的问题,研究了一种基于凌阳SPCE061A单片机的通用学习型红外遥控设计系统,该系统利用凌阳SPCE061A强大的语音功能,实现了语音提醒功能,并给出了部分硬件电路和软件设计方案.该学习型红外遥控器已广泛应用于多媒体教室、智能家居、家庭集中控制器等遥控设备.     

学习型红外遥控装置的研究与设计

红外遥控是目前常用的一种通信和遥控方法,但是目前各种产品的遥控并不能互相兼容,这就给实际应用带来了不便。本文研究了一种基于凌阳SPCE061A单片机的通用学习型红外遥控的方法,设计利用凌阳SPCE061A强大的语音功能,实现了语音提醒,体现了人性化的特点。文中给出了部分硬件电路以及软件设计方案。实验表明,该学习型红外遥控器可以广泛用于多媒体教室、智能家居、家庭集中控制器等遥控设备,较好地解决了各种产品的遥控不能互相兼容的问题。     

Signal set design with constrained amplitude spectrum and specifiedtime-bandwidth product

A new method for designing signals with a given time-bandwidth product, such that all the signals in the set have a flat amplitude spectrum and have low cross-correlation function values is introduced. It is shown that these signals lie on a signal parameter space ellipse. For a given duration and bandwidth, it is possible to trade off the cardinality of the set for better cross-correlation properties between remaining members of the set. Proof that the cross-correlation between these signals is bounded from above by a factor proportional to the square-root of inverse distance between these signals along one of the axes of the ellipse is given. It is also shown that the cross-correlation between two signals that are furthest apart is bounded by the square-root of inverse time-bandwidth product of the signals in the set. An example design is then given and a comparison of this signal set to some well-known signal sets illustrates that it performs better when the metric is maximum cross-correlation value. The proposed signal set also has the advantage that it can be designed for any time-bandwidth product instead of discrete values     

"假想层"在Needlee法膜系设计中的应用

Needle法是一种强大的膜系设计方法,它的突出特点是不依赖于初始膜系的给定,几乎对各种膜系设计目标都能给出比较令人满意的设计结果。但它的物理模型不够清楚,很难从直观上理解。通过在Needle法的推导过程中引入“假想层”的概念,使Needle法的整个推导过程清楚明了、容易理解,改进后的Needle法依然保持了它原来的各种优点。最后用两个设计实例说明了这种改进的有效性。     

Virtual path and link capacity design for ATM networks

A path and link capacity design method for asynchronous transfer mode (ATM) networks using statistical multiplexing of cells is proposed. By developing the design method, the statistical cell multiplexing effect can be exploited to significantly reduce required network resources. The necessary design procedures are identified. A simple and effective policing mechanism is proposed. An analytical method for the evaluation of cell multiplexing characteristics using declared parameters is provided. Path and link capacity design algorithms that use these techniques are proposed. The effectiveness of the proposed design procedure is confirmed by comparing analytical results to those from a computer simulation     

基于虚拟现实的森林公园景观的节能设计

针对传统方法存在节能效果差的问题,提出基于虚拟现实的森林公园景观的节能设计方案。对数据采集系统进行了节能优化设计,数据采集系统中的数据采集器是利用视觉影像的反衬图像的方法进行数据采集的,因此在使用过程中消耗电量极大,故对数据采集器以及控制电力系统进行了优化设计,这样能够有效地减少能源的消耗。在虚拟影像建立的过程中会使用边缘关联算子进行相关计算,实现电能的低量消耗。实验结果表明,采用基于虚拟现实的森林公园景观的节能效果较好,具有一定的优势。     

自适应交互多模型跟踪算法的模型集设计

自适应交互多模型算法（AIMM）是标准交互多模型算法（IMM）的一种改进。但AIMM遇到了新的问题，包括如何选择自适应模型集的结构，如何从基于旧模型集的滤波器中继承各种数据。本文分析了这些问题，并给出了AIMM中模型集和模型转移概率的设计方法。仿真结果表明，改进的AIMM算法比普通的AIMM算法的跟踪性能有明显的提高。     

基于三维虚拟景观的建模和虚拟设计

针对传统的景观虚拟设计艺术效果不理想的问题,进行基于三维虚拟景观的建模,并根据搭建的模型进行虚拟景观设计。利用三维虚拟动态空间进行实际景观外形描述,种子点匹配法分析景观纹理表征属性,搭建一个三维虚拟的景观模型。该模型作为设计基础,从景观室外地形特征和室内建筑构造两方面搭建虚拟景观整体造型,控制虚拟景观动态浏览,以此实现对于三维景观的虚拟设计。实验结果表明,与传统的虚拟设计相比,所设计的三维虚拟景观更加逼真,其艺术效果比传统设计提高的6.56%。由此可见,基于三维虚拟景观的建模和虚拟设计更加满足现代虚拟设计发展需求。