46360239
A New Algorithm for Subsumption Test
32944410
SPHINX - A Hybrid Knowledge Representation System
3145493
KPSP: A Knowledge Programming System based on Prolog
1326236
History Sensitive String for Multiple Alphabets
In most cases, to represent characters in a computer, conventional code systems such as ASCII, EBCDIC, or BCD, whose code-length is uniform, have been used. In some countries, where the native language is not English, people can easily adapt their alphabet to these code systems by simply replacing the Enghsh alphabet with the alphabet of their native language. In other countries, especially in Korea and Japan, a straightforward application of the conventional code system is not possible. This is because, to compose a sentence, people customarily intermix words each of which may be constructed by different alphabets. For example, in Korea, they have an alphabet for their native language called Hangul. Hangul is a complete language by which Koreans can communicate with each other. However, Korean culture was influenced by China and more recently by the western countries. This results in widespread usage of four different types of documents in Korea. Documents may be written in Hangul only, Hangul with Chinese words, Hangul with English words, and Hangul with both Chinese and English words. Even in these cases, Hangul is the main alphabet. Another example of the applications of multiple alphabets in a single text are the high level language programs in Korean environment where the program language is a popular high level language such as PASCAL, C, or LISP, but variable names or data in the program may consist of Korean characters [7,9]. In this case, the main alphabet is English. Another example using heterogeneous characters is the use of attributes such as color, size, or font in high quality text editors. In such cases, characters from multiple alphabets should be used in a computer. Since each alphabet may have characteristics different from each other, some coding methods for multiple alphabets can be considered. When the sizes of the alphabets are significantly different from each other, employment of codes of a uniform length is prohibitively expensive. There are two different techniques to encode the multiple alphabets into a single code system. In the following sections, two coding methods of multiple alphabets are generalized, and their advantages and disadvantages are analyzed.
39501622
A logic programming approach to hybrid knowledge representation
A new hybrid system called Sphinx is presented which combines classification-based reasoning with logic programming technique. It consists of two major components: a terminological component and an assertional one. The former uses a frame-based knowledge representation scheme based on classification and the latter is a theorem prover based on Horn logic. The assertional component can also handle a first-order query language and wh-questions. A new knowledge base maintenance mechanism based on the negation as failure inference rule enables Sphinx to support incremental assertions and retractions. In addition, Sphinx provides explanation capability to help the user in developing and debugging knowledge bases.
29923826
A Relational Dataflow Database Machine Based on Hierarchical Ring Network
5814506
Efficient Monitoring Algorithm for Fast News Alerts
Recently, there has been a dramatic increase in the use of XML data to deliver information over the Web. Personal Weblogs, news Web sites, and discussion forums are now publishing RSS feeds for their subscribers to retrieve new postings. As the popularity of personal Weblogs and RSS feeds grows rapidly, RSS aggregation services and blog search engines have appeared, which try to provide a central access point for simpler access and discovery of new content from a large number of diverse RSS sources. In this paper, we study how the RSS aggregation services should monitor the data sources to retrieve new content quickly using minimal resources and to provide its subscribers with fast news alerts. We believe that the change characteristics of RSS sources and the general user access behavior pose distinct requirements that make this task significantly different from the traditional index refresh problem for Web search engines. Our studies on a collection of 10,000 RSS feeds reveal some general characteristics of the RSS feeds and show that, with proper resource allocation and scheduling, the RSS aggregator provides news alerts significantly faster than the best existing approach.
36016648
Echo Watermarking in Sub-band Domain
Echo hiding is a method for embedding information, called watermark, into an audio signal. In general, echo hiding is processed in the time domain by convolving audio signal with echo kernel, without any consideration of the frequency characteristics. In this paper, we propose an echo hiding technique, which inserts echo into sub-band signal so as to take account into the frequency characteristics. The proposed echo hiding enables to embed high-energy echo, while minimizing the host audio quality distortion. In addition, the proposed allows increasing watermark capacity, since it is possible to embed simultaneously some watermark bits into different sub-band signals. The simulation results show that the proposed is more effective than the conventional echo hiding, in terms of watermark capacity and robustness against various attacks.
43684392
Wavelet Analysis Based Blind Watermarking for 3-D Surface Meshes
As most previous wavelet analysis based 3-D mesh watermarking methods embed the watermark information into wavelet coefficients arranged in a certain order, they have not been used as blind schemes since the connectivity information must be exactly known in the watermark extraction process. In this paper, we propose a blind watermarking method based on wavelet analysis for 3-D mesh model. Two new techniques are introduced. One is to exploit the statistical features of scale coefficients on an approximation (low resolution) level for watermark embedding. Another is to extract the hidden watermark, not from the same resolution level as used in embedding process, but directly from the spatial domain. As the proposed watermark detection does not require the wavelet analysis, any pre-processing such as registration and re-sampling, is not needed. These techniques allow to detect the watermark without referring to the original meshes. In addition, the proposed are applicable directly to irregular meshes by using irregular wavelet analysis. Through simulations, we prove that our method is fairly robust against various attacks including topological ones.
18975029
An asymptotic analysis of band-limited DS/SSMA communication systems
A new asymptotic analysis is presented to establish whether or not commonly used techniques to approximate the performance of direct-sequence spread-spectrum multiple-access (DS/SSMA) systems still apply when the systems are strictly band limited. The results apply to any linear data modulation and spreading scheme. The interference components, including the interchip interference (ICI) of a linear receiver output, are shown to be asymptotically jointly Gaussian random variables conditioned on the phases and delays of the interfering signals. Expressions for the error probabilities of band-limited systems are also developed from this result.
6528301
Energy Efficient Broadcast in Wireless Ad hoc Networks with Hitch-hiking
In this paper, we have proposed a novel concept called Hitch-hiking in order to reduce the energy consumption of broadcast application for wireless networks. Hitch-hiking takes advantage of the physical layer design that facilitates the combining of partial signals to obtain the complete information. The concept of combining partial signals using maximal ratio combiner [13] has been used to improve the reliability of the communication channel but has never been exploited to reduce energy consumption. We propose a centralized heuristic algorithm called Wireless Multicast with Hitch-hiking (WMH) to construct an energy efficient tree using Hitch-hiking and also present a distributed version of the heuristic. We also evaluate the proposed heuristics through simulation. Simulation results show that Hitch-hiking can reduce the transmission cost of broadcast by as much as 50%. Further, we propose and evaluate a protocol called PSBT that reduces energy consumption of broadcast by eliminating redundancy in receive operation. Finally, we propose an algorithm that takes advantage of both Hitch-hiking and PSBT in conserving energy.