The estimation process begins by assuming or hypothesizing that the least squares linear regression
model (drawn from a sample) is valid. The formal two-variable linear regression model is based on
the following assumptions:
(1) The population regression is adequately represented by a straight line: E(Yi) = μ(Xi) = β0 + β1Xi
(2) The error terms have zero mean: E(∈i) = 0
(3) A constant variance (homoscedasticity): V(∈i) = σ2
The final chapter of the book presents an innovative method for fluid mechanical
design in which an object within the flow field is build element-by-element. Each
element is introduced into the flow, and its effect on a cost function is minimized with
respect to the object’s position. An element may represent added material or a
removed part of the existing structure. This chapter presents a strong degree of
All geographic information systems (GIS) are built
using formal models that describe how things are
located in space. A formal model is an abstract and
well-defined system of concepts. It defines the
vocabulary that we can use to describe and reason
about things. A geographic data model defines the
vocabulary for describing and reasoning about the
things that are located on the earth. Geographic data
models serve as the foundation on which all
geographic information systems are built.
We are all familiar with one model for geographic
As I am finishing this book, Science magazine is running a special issue about the
sequencing of the macaque genome. It turns out that macaques share about 93 percent
of their genes with us, humans. Previously it has been already reported that
chimpanzees share about 96 percent of their genes with us. Yes, the macaque is our
common ancestor, and it might be expected that, together with the chimps, we continued
with our natural selection some 23 million years ago until, some 6 million
years ago, we departed from the chimps to continue our further search for better
A basic problem that must be dealt with in order to build an intelligent tutoring system (ITS) in the domain of foreign language teaching is that of establishing what kind of grammatical knowledge has to be included in the domain expert module. Two basic options are possible: (i) to use a naive or pedagogical grammar, comprising knowledge derived from textbooks and school grammars or (ii) to use one of the formal grammars developed by theoretical and computational linguists.
We proposed in this paper an approach for checking the conformability in CORBA component model specifications. In software engineering, it is demonstrated that discovering bugs in earlier phases is much more economical than later phases. We focused thus on verifying components by their ports specification. In order to do this, firstly we determined constraints on kinds of port as well as on types of port which the connection between ports must satisfy, and then formalized them to be able to prove automatically using formal prover tools.
Formal methods mathematical languages, techniques and tools, used to specify and verify systems, goal is help engineers construct more reliable systems. Introduction to Formal Methodspresents about introduction; formal specification; formalformal verificationverification; model checking; theorem proving.
The relational Model of Data is based on the concept of a Relation.
A Relation is a mathematical concept based on the ideas of sets.
The strength of the relational approach to data management comes from the formal foundation provided by the theory of relations.
We review the essentials of the relational approach in this chapter.
The aim of this work is to present some preliminary results of an investigation in course on the typology of the morphology of the native South American languages from the point of view of the formal language theory. With this object, we give two contrasting examples of descriptions of two Aboriginal languages ﬁnite verb forms morphology: Argentinean Quechua (quichua santiague˜ o) and Toba.
The paper investigates the problem of providing a formal device for the dependency approach to syntax, and to link it with a parsing model. After reviewing the basic tenets of the paradigm and the few existing mathematical results, we describe a dependency formalism which is able to deal with long-distance dependencies. Finally, we present an Earley-style parser for the formalism and discuss the (polynomial) complexity results.
Dominance links were introduced in grammars to model long distance scrambling phenomena, motivating the deﬁnition of multiset-valued linear indexed grammars (MLIGs) by Rambow (1994b), and inspiring quite a few recent formalisms. It turns out that MLIGs have since been rediscovered and reused in a variety of contexts, and that the complexity of their emptiness problem has become the key to several open questions in computer science.
In spoken dialogue systems, Partially Observable Markov Decision Processes (POMDPs) provide a formal framework for making dialogue management decisions under uncertainty, but efﬁciency and interpretability considerations mean that most current statistical dialogue managers are only MDPs. These MDP systems encode uncertainty explicitly in a single state representation.
We present a statistical phrase-based translation model that uses hierarchical phrases— phrases that contain subphrases. The model is formally a synchronous context-free grammar but is learned from a bitext without any syntactic information. Thus it can be seen as a shift to the formal machinery of syntaxbased translation systems without any linguistic commitment. In our experiments using BLEU as a metric, the hierarchical phrasebased model achieves a relative improvement of 7.5% over Pharaoh, a state-of-the-art phrase-based system. ...
Minimal Recursion Semantics (MRS) is the standard formalism used in large-scale HPSG grammars to model underspeciﬁed semantics. We present the ﬁrst provably efﬁcient algorithm to enumerate the readings of MRS structures, by translating them into normal dominance constraints.
Following this tradition, many researchers recognize their usefulness in the description of language - - even if they do not agree on their significance . However, a weak or strong commitment to this notion does not elude the fact that it proves to be very difficult to settle on a finite set of labels along with their formal definitions. The dilemma resulting from this challenge is well known: to require a univocal identification by each role results in an increase in their number while to abstract their semantic content gives rise to an inconsistent set. ...
This paper shows how to formally characterize language learning in a finite parameter space as a Markov structure, hnportant new language learning results follow directly: explicitly calculated sample complexity learning times under different input distribution assumptions (including CHILDES database language input) and learning regimes. We also briefly describe a new way to formally model (rapid) diachronic syntax change.
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. ...