This paper presents empirical studies and closely corresponding theoretical models of the performance of a chart parser exhaustively parsing the Penn Treebank with the Treebank’s own CFG grammar. We show how performance is dramatically affected by rule representation and tree transformations, but little by top-down vs. bottom-up strategies.
A natural next step in the evolution of constraint-based grammar formalisms from rewriting formalisms is to abstract fully away from the details of the grammar mechanism--to express syntactic theories purely in terms of the properties of the class of structures they license.
Model-theoretic semantics provides a computationally attractive means of representing the semantics of natural language. However, the models used in this formalism are static and are usually infinite. Dynamic models are incomplete models that include only the information needed for an application and to which information can be added. Dynamic models are basically approximations of larger conventional models, but differ is several interesting ways. The difference discussed here is the possibility of inconsistent information being included in the model. ...
We analyze estimation methods for DataOriented Parsing, as well as the theoretical criteria used to evaluate them. We show that all current estimation methods are inconsistent in the “weight-distribution test”, and argue that these results force us to rethink both the methods proposed and the criteria used.
We use multiple views for cross-domain document classiﬁcation. The main idea is to strengthen the views’ consistency for target data with source training data by identifying the correlations of domain-speciﬁc features from different domains. We present an Information-theoretic Multi-view Adaptation Model (IMAM) based on a multi-way clustering scheme, where word and link clusters can draw together seemingly unrelated domain-speciﬁc features from both sides and iteratively boost the consistency between document clusterings based on word and link views. ...
We present a game-theoretic model of bargaining over a metaphor in the context of political communication, ﬁnd its equilibrium, and use it to rationalize observed linguistic behavior. We argue that game theory is well suited for modeling discourse as a dynamic resulting from a number of conﬂicting pressures, and suggest applications of interest to computational linguists.
Model-theoretic pragmatics is an attempt to provide a formal description of the pragmatics of natural language as effects arising from using model-theoretic semantics in a dynamic environment. The pragmatic phenomena considered here have been variously labeled ~resupposition [I] and eonven¢ional implicature . The models used in traditional model-theoretic semantics provide a complete and static representation of knowledge about the world, llowever, this is not the environment in which language is used. ...
From its inception as a brief journal article in 1929, the Publication Manual of
the American Psychological Association has been designed to advance scholarship
by setting sound and rigorous standards for scientific communication. The
creators of the 1929 manuscript included psychologists, anthropologists, and business
managers who convened under the sponsorship of the National Research Council.
They sought to establish a simple set of procedures, or style rules, that would codify
the many components of scientific writing to increase the ease of reading comprehension.
In responding to the guidelines established by the session chairman of this panel, three of the five topics he set forth will be discussed. These include aggregate functions and quantity questions, querying semantically complex fields, and multi-file queries. As we will make clear in the sequel, the transformational apparatus utilized in the TQA Question Answering System provides a principled basis for handling these and many other problems i n natural language access to databases.
A back -propagation artificial neural net has been trained to estimate the activity values of a set of 18 N-alkyl-N-acyl- -aminoamide derivatives from the results of molecular mechanics and RHF/PM3/SCF MO semi-empirical calculations. The input descriptors include molecular properties such as the partition coefficient P, 3d structure dependent parameters, charge dependent parameters, and topological descriptors.
Recently, there has been a rise of interest in unsupervised detection of highlevel semantic relations involving complex units, such as phrases and whole sentences. Typically such approaches are faced with two main obstacles: data sparseness and correctly generalizing from the examples. In this work, we describe the Clustered Clause representation, which utilizes information-based clustering and inter-sentence dependencies to create a simpliﬁed and generalized representation of the grammatical clause. ...
Although there have been many experimental systems for natural-language access to databases, with some now going into actual use, many problems in this area remain to be solved. The purpose of this panel is to put some of those problems before the conference. The panel's motivation stems partly from the fact that, too often in the past, discussion of natural-language access to databases has focused, at the expense of the underlying issues, on what particular systems can or cannot do. To avoid this, the discussions of the present panel will be organized around issues rather than systems. ...
A computational vehicle for lexicography was designed to keep to the constraints of meaningtext theory: sets of lexical correlates, limits on the form of definitions, and argument relations similar to lexical-functional grA--~-r. Relational data bases look like a natural framework for this. But linguists operate with a nonnormalized view. Mappings between semantic actants and grammatical relations do not fit actant fields uniquely. Lexical correlates and examples are polyvalent, hence denormalized. ...
Review of empirical relationships between inlet cross-section and tidal prism. This contribution compares some theoretical elaborations both qualitatively and quantitatively, confront these with US and Dutch empirical data and discuss their pros and cons for practical applications.
Trên cơ sở vật liệu sẵn có tại địa phương, dùng phương pháp lý thuyết kết hợp thực nghiệm chế tạo hỗn hợp vữa lỏng mác cao dùng để xử lý mối nối cho các cấu kiện bê tông bán tiền chế đáp ứng yêu cầu về độ lưu động, về cường độ đồng thời mang lại hiệu quả kinh tế.
The other group of articles is rather empirical in nature and estimate a long-run
relationship between the aggregated value of credit and a set of standard macroeconomic
factors such as output, prices or interest rates. The main ¯nding of these studies is that
for most countries the value of credit tend to increase with GDP and asset prices, and
to decrease with the level of interest rates (see Egert et al., 2007 and references therein).
Low-density parity-check (LDPC) codes are forward error-correction codes,
first proposed in the 1962 PhD thesis of Gallager at MIT. At the time, their
incredible potential remained undiscovered due to the computational demands
of simulation in an era when vacumm tubes were only just being replaced by
the first transistors. They remained largely neglected for over 35 years. In the
mean time the field of forward error correction was dominated by highly structured
algebraic block and convolutional codes.
Exhaustive testing (use of all possible inputs and conditions) is impractical
must use a subset of all possible test cases.
must have high probability of detecting faults.
Need thought processes that help to select test cases more intelligently.
test case design techniques are such thought processes.Effective testing: find more faults.
focus attention on specific types of fault.
know you're testing the right thing.
Efficient testing: find faults with less effort.
systematic techniques are measurable...
Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article An Information-Theoretic Approach for Energy-Efﬁcient Collaborative Tracking in Wireless Sensor Networks
Chip Firing Games on (directed) graph are widely used in theoretical computer science and many other sciences. In this model, chips are ﬁred from one vertex to all of its neighbors at the same time. The purpose of our paper is to study an extended version of this model, the Conﬂicting Chip Firing Game, by considering that chips can be ﬁred from one vertex to one of its neighbors at each time. Our main results are obtained when the support graph of this game is a rooted tree. we show