11611476
Conceptual graphs as schemas for semi-structured databases
As the World Wide Web grows dramatically in recent years, there is increasing interest in semi-structured data on the web. Semi-structured data are usually represented in graph format, many graph schemas have then been proposed to extract schemas from those data graphs. Conceptual graphs, which use incremental conceptual clustering method to extract schemas, have initially been proposed in 2000. In this paper, we revise the original algorithm to generate a conceptual graph by proposing some new operators in the construction process. The results have shown that with the revised algorithm the quality of the conceptual graphs has been improved in terms of query optimization.
690242
Improving Quality of Email Categorization with Tournament Methods
The tournament text classification methods are proposed in this article to perform the task of email categorization, in which the essence is to break down the multi-class categorization process into a set of binary classification tasks. We implement the methods of elimination and Round Robin tournament to classify emails within 15 folders. Substantial experiments are conducted to compare the effectiveness and robustness of the tournament methods against the n-way classification method and the voting method. The experimental results show that the tournament methods outperform the n-way method by 11.7% and the voting method by 4.1% regarding precision, and the Round Robin performs slightly better than the Elimination tournament on average.
16840924
Improving Transliteration with Precise Alignment of Phoneme Chunks and Using Contextual Features
Automatic transliteration of foreign names is basically regarded as a diminutive clone of the machine translation (MT) problem. It thus follows IBM's conventional MT models under the source-channel framework. Nonetheless, some parameters of this model dealing with zero-fertility words in the target sequences, can negatively impact transliteration effectiveness because of the inevitable inverted conditional probability estimation. Instead of source-channel, this paper presents a direct probabilistic transliteration model using contextual features of phonemes with a tailored alignment scheme for phoneme chunks. Experiments demonstrate superior performance over the source-channel for the task of English-Chinese transliteration.
37472111
Extending the superimposed codeword indexing scheme to handle incomplete information
In order to use Prolog as a basis for database applications, techniques are required for rapid retrieval of clauses from large data sets. Various researchers have contributed to the development of indexing strategies for this purpose. One such strategy is known as superimposed codeword+mask bits (SCW+MB). One extension of Prolog which is useful in the development of deductive databases is the ability to handle incomplete information. A form of incomplete information based on sets has been introduced and used in a deductive database system. In order to provide efficient access to clauses containing incomplete information, existing strategies need to be adapted accordingly. This paper presents an extension to the SCW+MB algorithm to cover incomplete information, and describes how this can be realized in hardware.
1165688
A Chinese dictionary construction algorithm for information retrieval
In this article we propose a method for constructing, from raw Chinese text, a statistics-based automatic dictionary. The method makes use of local statistical information (i.e., data within a document) to identify and discard repeated string patterns, which, at an earlier stage, were substrings of legitimate words. Global statistical information (which exists throughout the entire corpus) and contextual constraints are then used for further filtering. The method can be used to alleviate the out-of-vocabulary (OOV) problem, which is commonly found in dictionary-based natural language information-processing applications, e.g., word segmentation. It can handle text corpora dynamically and, further, it does not impose any strict requirements on the size and quality of the training corpora. Based on our method, we constructed Chinese dictionaries from different Chinese corpora. We then applied the words in the constructed dictionaries to indexing in information retrieval (IR). Retrieval performance using such indexes was compared to the same, but based on indexes produced by static dictionaries. Three Chinese corpora using various character-encoding schemes and language styles were used in the experiments. The results show that retrieval using indexes based on the constructed dictionary is effective. This implies that fully automatic Chinese dictionary construction based on dynamic data sources, e.g., from the Internet, for the purposes of IR is feasible. Drawing on the experiment, we were able to make some interesting observations: (1) using only a portion of a dictionary is enough to produce good retrieval performance, e.g., a dictionary consisting of only the 500 highest-frequency strings extracted from the NTCIR 2 Chinese corpus produced as good a retrieval result as using a more complete dictionary with over 100K entries; and (2) complete word segmentation is not a strict requirement for achieving practical information retrieval.
12876616
A Design of Temporal Event Extraction from Chinese Financial News
This paper presents an information system for Chinese Information Extraction from Financial news (CHIEF). The ultimate target of the system is to extract information concerning the occurrence time and places of the financial activities in the different companies from a local Hong Kong newspaper, namely (Tao Kung Pao). To facilitate event extraction purpose, two groups of templates were defined, i.e. the company related and company restructuring templates. They are used to select the desired information for each type of financial activities, such as (bankruptcy) or (merge). Each specific event is then represented using a frame-based knowledge structure. Two types of slots are embedded in each frame: they are the activity- and time-related slots. Based on these slots, multiple activities are interconnected according to their entity relations, temporal relations or the deduced relations. Effectively, CHIEF is a question-answering system designed for handling the company related queries, event based queries, temporal queries and complex queries in a finance domain.
37272834
Issues in Integrating Schemas for Reverse Engineering
Abstract After adopting a standard format such as GXL to exchange graphs of artifacts for reverse engineering tools, the next logical step is to define an appropriate schema for the information contained in the graphs. Various researchers have developed schemas, but in practice, it is still hard to choose an existing one. Typically, researchers end up needing to implement new schemas for the particulars of their tools or case studies. In the paper, we discuss a potential scenario for integrating schemas, with the aim of improving the interoperability among reverse engineering tools.
3120289
Recursive Recovery of Position and Orientation from Stereo Image Sequences without Three-Dimensional Structures
Traditional vision-based 3-D motion estimation algorithms for robots require given or calculated 3-D models while the motion is being tracked. We propose a high-speed extended-Kalman-filter-based approach that recovers position and orientation from stereo image sequences without prior knowledge as well as the procedure for the reconstruction of 3-D structures. Empowered by the use of the trifocal tensor, the computation step of 3-D models can be eliminated. The algorithm is thus more flexible and can be applied to a wide range of domains. The twist motion model is also adopted to parameterize the 3-D motion such that the motion representation in the proposed algorithm is robust and minimal. As the number of parameters to be estimated is reduced, our algorithm is more efficient, stable and accurate compared to traditional approaches. The proposed method has been verified using a real image sequence with ground truth.
3178984
Work-conserving distributed schedulers for Terabit routers
Buffered multistage interconnection networks offer one of the most scalable and cost-effective approaches to building high capacity routers. Unfortunately, the performance of such systems has been difficult to predict in the presence of the extreme traffic conditions that can arise in the Internet. Recent work introduced distributed scheduling, to regulate the flow of traffic in such systems. This work demonstrated, using simulation and experimental measurements, that distributed scheduling can deliver robust performance for extreme traffic. Here, we show that distributed schedulers can be provably work-conserving for speedups of 2 or more. Two of the three schedulers we describe were inspired by previously published crossbar schedulers. The third has no direct counterpart in crossbar scheduling. In our analysis, we show that distributed schedulers based on blocking flows in small-depth acyclic flow graphs can be work-conserving, just as certain crossbar schedulers based on maximal bipartite matchings have been shown to be work-conserving. We also study the performance of practical variants of these schedulers when the speedup is less than 2, using simulation.
33091738
SHAPES: A Novel Approach for Learning Search Heuristics in Under-Constrained Optimization Problems
Although much research in machine learning has been carried out on acquiring knowledge for problem-solving in many problem domains, little effort has been focused on learning search-control knowledge for solving optimization problems. This paper reports on the development of SHAPES, a system that learns heuristic search guidance for solving optimization problems in intractable, under-constrained domains based on the Explanation-Based Learning (EBL) framework. The system embodies two new and novel approaches to machine learning. First, it makes use of explanations of varying levels of approximation as a mean for verifying heuristic-based decisions, allowing heuristic estimates to be revised and corrected during problem-solving. The provision of such a revision mechanism is particularly important when working in intractable and under-constrained domains, where heuristics tend to be highly over-generalized, and hence at times will give rise to incorrect results. Second, it employs a new linear and quadratic programming-based weight-assignment algorithm formulated to direct search toward optimal solutions under best-first search. The algorithm offers a direct method for assigning rule strengths and, in so doing, avoids the need to address the credit-assignment problem faced by other iterative weight-adjustment methods.
7622452
Tracking based motion segmentation under relaxed statistical assumptions
We present a novel and efficient motion segmentation and tracking algorithm that follows the shift and align paradigm. We introduce two statistical tests to evaluate the similarity of aligned image pixels or patches and we use them to determine the spatial extend of each segment. The one statistical test is fast and accurate when the noise is moderate and the other employs a sophisticated noise model involving the Mahalanobis distance to handle correlated noise. Direct computation of the Mahalanobis distance is prohibitively expensive so we apply the Sherman-Morrison-Woodbury identity and amortization to reduce the cost by several orders of magnitude. We tested both versions of the algorithm on a variety of image sequences (indoor and outdoor, real and synthetic, constant and varying lighting, stationary and moving camera, one of them with known ground truth) with very good results.