15594560
FRM-Based FIR Filters with Minimum Coefficient Sensitivities
A method for optimizing FRM-based FIR filters with optimum coefficient sensitivity is presented. This technique can be used in conjunction with nonlinear optimization techniques to design very sharp filters that do not only have very sparse coefficient values but also very low coefficient sensitivity.
17955850
Signed power-of-two allocation scheme for the design of lattice orthogonal filter banks
In signed power-of-two (SPT) coefficient digital filter design, it is well known that a better frequency response performance can be achieved if the number of SPT terms for each coefficient is not limited to a fixed number but instead, is allowed to vary subject to a given number of total SPT terms for the filter. Many SPT term allocation schemes have been developed for distributing the number of SPT terms to the coefficients. In this paper, an SPT term allocation scheme is developed for the design of lattice orthogonal filter banks. The SPT terms are allocated to coefficients one at a time to minimize the frequency response errors due to rounding the coefficients to SPT numbers. Examples show that the proposed allocation scheme is eminently suitable for the design of SPT coefficient lattice filter banks. It is superior to those reported in the literature.
7801331
FPGA implementation of digital filters synthesized using the frequency-response masking technique
The effective length of a filter designed using the frequency-response masking technique is very high and requires a very large number of delay elements. In this paper, we present some useful techniques for reducing the data transfer between the FPGA and external memory when the random logic are implemented using FPGA and the delay elements are implemented using external memory such as DRAM.
2854649
Frequency-response-masking technique incorporating extrapolated impulse response band-edge shaping filter
Techniques based on the frequency-response masking (FRM) approach are known to be highly efficient for achieving drastic reduction of the number of multipliers and adders in narrow transition band linear-phase finite-impulse response (FIR) filters. Basic FRM structure comprises a band-edge shaping filter and two masking filters. It is observed that the impulse response of the band-edge shaping filter of FRM shows quasi-periodic property. Previous study demonstrated that the quasi-periodic property of the impulse responses of lowpass or highpass digital FIR filters can be exploited to reduce the complexity of the filter by using extrapolated impulse response technique. Extrapolating the idea, the band-edge shaping filter in FRM may be designed by the extrapolated impulse response technique. In this paper, an FRM technique incorporating extrapolated impulse response band-edge shaping filter is introduced. An iterative optimization procedure is proposed to design the FRM subfilters. An example taken from the literature is used to illustrate that the number of multipliers produced by our technique is less than 80 percent of earlier results.
31072695
Making XML document markup international
In name and in practice, the World-Wide Web (hereafter Web) is used around the World beyond English-speaking areas. This creates a tremendous need to internationalize standard terminology used in the technologies that make the Web possible. Existing efforts on XML internationalization (i18n) and localization (i10n) have focused on the content of XML documents instead of the terms used in markup (annotations) such as elements and attributes. The SGML standard ISO 8879 supports the use of Unicode (ISO 10646) throughout a document, including markups. However, most elements and attributes of XML documents are still defined in English, thereby limiting their use among non-English speakers. This paper presents an XSLT-based method that can completely localize the markup of XML documents into different natural languages. We also describe how the proposed technique can be applied to translation problems in programming (e.g. C and Java) or documentation (e.g. LATEX or other formatting languages) so that a program or a document can be converted to and from an XML format.
17008107
A Rendering Equation for Specular Transfers and Its Integration into Global Illumination
In this paper, we present a rigorous theoretical formulation of the fundamental problem—indirect illumination from area sources via curved ideal specular surfaces. Intensity and area factors are introduced to clarify this problem and to rectify the radiance from these specular surfaces. They take surface geometry, such as Gaussian curvature, into account. Based on this formulation, an algorithm for integrating ideal specular transfers into global illumination is also presented. This algorithm can deal with curved specular reflectors and transmitters. An implementation is described based on wavefront tracing and progressive radiosity. Sample images generated by this method are presented.
46180
Efficient visibility processing for projective texture mapping
Abstract Projective texture mapping is a powerful tool for image-based rendering. However, visibility information must be obtained in order to project correct textures onto the geometric sturcture. This paper presents a novel visibility algorithm for determining which polygons are visible from each camera position. It has object-space precision, but operates in both image-space and object-space to get better performance. It generates much less polygons than traditional object-space algorithms to help accelerate the speed of texture mapping. The techniques used to achieve these are conservative image-space occlusion testing and object-space shallow clipping . This algorithm has been successfully used to generate large-scale image-based rendering of a whole university campus, and image-based rendering of architectures under dynamic lighting.
5687277
A self-adaptive scheduling algorithm of on-demand broadcasts
In mobile wireless systems data on air can be accessed by a large number of mobile users. Many of these applications such as wireless internets and traffic information systems are pull-based, that is, they respond to on-demand user requests. In this paper, we study the scheduling problems of on-demand broadcast environments. Traditionally, the response time of the requests has been used as a performance measure. In this paper we consider the performance as the average cost of request composed of three kinds of costs—access time cost, tuning time cost, and cost of handling failure request. Our main contribution is a self-adaptive scheduling algorithm named LDFC, which computes the delay cost of data item as the priority for broadcast. It performs well compared with some previous algorithms in this context.
5664063
Parallel Progressive Radiosity with Adaptive Meshing
Radiosity plays an important role in computer graphics. This paper presents an efficient parallel algorithm for progressive radiosity with adaptive meshing, which adopts a novel static processor assignment strategy and takes advantages of hierarchical computation structure in this problem to minimize communication and balance dynamic load. Our experiments on a Meiko CS-2 distributed memory machine show that this algorithm has achieved good performance for the tested cases.