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1.
36 Problems for Semantic Interpretation - Gabriele Scheler
This paper presents a collection of problems for natural language analysis
derived mainly from theoretical linguistics. Most of these problems
present major obstacles for computational systems of language interpretation.
The set of given sentences can easily be scaled up by introducing more
examples per problem. The construction of computational systems could
benefit from such a collection, either using it directly for training and
testing or as a set of benchmarks to qualify the performance of a NLP
system.
1 Introduction
The main part of this paper consists of a collection of problems for semantic
analysis of natural language. The problems are arranged in the following way:
example sentences
concise description of the...
2.
The Graham Scan Triangulates Simple Polygons - Xianshu Kong,Hazel Everett,Godfried Toussaint
The Graham scan is a fundamental backtracking technique in computational geometry which was originally designed to compute the convex hull of a set of points in the plane and has since found application in several different contexts. In this note we show how to use the Graham scan to triangulate a simple polygon. The resulting algorithm triangulates an n vertex polygon P in O(kn) time where k-1 is the number of concave vertices in P. Although the worst case running time of the algorithm is O(n 2 ), it is easy to implement and is therefore of practical interest. 1....
3.
Interaction of Nonlinear Schrödinger Solitons with an External Potential - Helge Frauenkron,Peter Grassberger
Employing a particularly suitable higher order symplectic integration algorithm, we integrate the 1-d nonlinear Schrodinger equation numerically for solitons moving in external potentials. In particular, we study the scattering off an interface separating two regions of constant potential. We find that the soliton can break up into two solitons, eventually accompanied by radiation of non-solitary waves. Reflection coefficients and inelasticities are computed as functions of the height of the potential step and of its steepness.
4.
Exploration Bonuses and Dual Control - Peter Dayan,Terrence J Sejnowski
Finding the Bayesian balance between exploration and exploitation in adaptive
optimal control is in general intractable. This paper shows how to compute suboptimal
estimates based on a certainty equivalence approximation arising from a form of
dual control. This systematizes and extends existing uses of exploration bonuses in
reinforcement learning (Sutton, 1990). The approach has two components: a statistical
model of uncertainty in the world and a way of turning this into exploratory behaviour.
It is applied to two-dimensional mazes with moveable barriers.
1 Introduction
Reinforcement learning techniques are often applied in problems whose challenge stems
from the ignorance of the solvers about the nature of their environments. For instance,...
5.
Daily management of an earth observation satellite: comparison of ILOG Solver with dedicated algorithms for Valued Constraint Satisfaction Problems - Michel Lemaitre
The daily management of an earth observation satellite like Spot is
a difficult combinatorial optimization problem. A simplified form of this
problem can be stated as follows : given (1) a set of candidate photographs
for the next day, each one associated with a weight reflecting its importance,
(2) a set of imperative constraints expressing physical limitations
(non overlapping of photographs, respect of camera transition times, limitation
of the instantaneous data flow), select a subset of candidates which
meets all the constraints and which maximizes the sum of the weights of
the selected candidates. This problem can be stated as a Valued Constraint
Satisfaction Problem, a general framework for...
6.
Hierarchical MRF Modeling For Sonar Picture Segmentation
This paper deals with sonar image segmentation based
on a hierarchical markovian modelization.
This model takes into account both the phenomenon
of speckle noise through Rayleigh's law, and notions of
geometry corresponding to geometric object shadows.
We adopt an 8-connexity neighbourhood in order to
dicriminate geometric and no-geometric shadows. The
Markov Random Field (MRF) are well adapted for this
kind of segmentation where a priori knowledge about
the shapes we are searching is available. We propose
some new results on real sonar pictures obtained with
a multigrid algorithm. The hierarchical modelization
allow to successfully improve the sonar image segmentation
as it will be shown.
1. SHADOW DETECTION IN SONAR
IMAGERY
Because of its high-resolution performance a...
7.
An Analytical Evaluation of Static Coupling Measures for Domain Object Classes - Geert Poels
We present a set of static coupling measures for
domain object classes. Although these measures
do not directly measure the external quality of an
OO software system, they might be useful as early
indicators of high-risk components of the system.
In this paper we focus on the analytical evaluation
of the measures using a well-known set of generic
coupling properties.
1. INTRODUCTION
Whereas software users are primarily interested in
quality attributes such as for instance defined in
the ISO 9126 standard (i.e., functionality, reliability,
efficiency, usability, maintainability, portability),
these are external software product attributes that
can only be evaluated with respect to how the
software product relates to its environment. During
software development software products are
mostly...
8.
A Partial Approach to the Problem of Deadlocks in Processes With Resources
In the modeling and control of manufacturing systems one of the aims is to obtain a system
that can run in an automatic way. This means that the software in charge of the monitoring and
control of the system must be able to deal with a set of problematic situations (system failures,
system deadlocks, overflow of storing facilities, etc.). In this paper we are going to concentrate
on one of the previous problems: the deadlock problem. Deadlock problems are very usual in
concurrent system where, even if the execution of each process is correct, the competition of a set
of processes for the same set of...
9.
Conjunctive Query Containment in Description Logics with n-ary Relations - Diego Calvanese,Giacomo Maurizio Lenzerini
Recent research points out that query containment
is a central problem in several
database and knowledge base applications, including
data warehousing, data integration,
query optimization, and (materialized) view
maintenance. In this paper we present a decision
procedure for containment of conjunctive
queries defined over a database schema
specified in a very expressive description logic,
comprising n-ary relations and general inclusion
axioms on both concepts and relations.
1 Introduction
Query containment is the problem of checking whether
for every data (or knowledge) base, the result of one
query is always a subset of the result of another query.
Many recent papers point out that query containment
is a central problem in several database and knowledge
base applications, including...
10.
Optimized Software Synthesis for Digital Signal Processing Algorithms -- An Evolutionary Approach - Jurgen Teich,Eckart Zitzler,Shuvra S. Bhattacharyya
This paper addresses the problem of trading-off between the minimization of program
and data memory requirements of single-processor implementations of dataflow
programs. Based on the formal model of synchronous data flow (SDF) graphs
[ LM87 ] , so called single appearance schedules are known to be program-memory
optimal. Among these schedules, buffer memory schedules are investigated and
explored based on a two-step approach: (1) An Evolutionary Algorithm (EA) is
applied to efficiently explore the (in general) exponential search space of actor firing
orders. (2) For each order, the buffer costs are evaluated by applying a dynamic programming
post-optimization step (GDPPO). This iterative approach is compared
to existing heuristics for...
11.
Learning Planning Operators by Observation and Practice - Xuemei Wang
The work described in this paper addresses learning
planning operators by observing expert agents and subsequent
knowledge refinement in a learning-by-doing
paradigm. The observations of the expert agent consist
of: 1) the sequence of actions being executed,
2) the state in which each action is executed, and 3)
the state resulting from the execution of each action.
Planning operators are learned from these observation
sequences in an incremental fashion utilizing a
conservative specific-to-general inductive generalization
process. In order to refine the new operators
to make them correct and complete, the system uses
the new operators to solve practice problems, analyzing
and learning from the execution traces of the resulting
solutions or execution failures. We...
12.
Low Latency Word Serial CORDIC - J. Villalba,T. Lang,Julio Villalba
In this paper we present a modification of the CORDIC algorithm which reduces the number
of iterations almost to half by merging two successive iterations of the basic algorithm. The two
coefficients per iteration are obtained with only a small increase in the cycle time by estimating one
of the coefficients. A correcting iteration method is used to correct the possible errors produced by
the estimate. Moreover, the modified iteration permits the reduction of the number of cycles required
for the compensation of the scaling factor. The resulting architecture is word serial, working both
in rotation and vectoring operation modes, presenting a low latency in comparison...
13.
Toward a Plan Steering Agent: Experiments with Schedule Maintenance - Tim Oates,Paul R. Cohen
When a plan involves hundreds or thousands of events over time
it can be difficult or impossible to tell whether those events are unfolding
"according to plan" and to assess the impact of dynamic plan
modifications. Pathological states may arise in which goals cannot be
attained or are attained too slowly. Plan steering is an agent-based
approach to this problem. The agent monitors an unfolding plan, detects
and predicts pathological situations, and develops dynamic plan
modifications that will steer the plan around the problem. We present
results for such a system that performs the related task of schedule
maintenance in the transportation planning domain. The agent uses
limited domain knowledge...
14.
Possessive Affixes and Complement Composition - Dimitra Kolliakou
A long-standing issue in the literature on clitics, namely, whether they can
be best analysed as affixes or syntactically autonomous words (postlexical
clitics), is here addressed with respect to the Modern Greek `weak form'
possessive pronoun. It is argued that distributional and phonological evidence
strongly support an affixal analysis. Apparent difficulties for extending
to possessive affixes an HPSG account that has been previously employed
for pronominal affixation in Romance VP are overcome, and a composition
approach is proposed -- one which takes a categorial grammar approach to
adjectives and treats them as heads in NP, and does not require flat NP
structures that lack independent motivation in Modern Greek.
1...
15.
Decomposition of Representations of CAR Induced by Bogoliubov Endomorphisms - Jens Bockenhauer
In a Fock representation, a non-surjective Bogoliubov transformation of CAR leads to a reducible
representation. For the case that the corresponding Bogoliubov operator has finite corank, the
decomposition into irreducible subrepresentations is clarified. In particular, it turns out that the
number of appearing subrepresentations is completely determined by the corank.
1 Introduction
Unitary i.e. surjective Bogoliubov operators U correspond to Bogoliubov automorphisms % U of the
canonical anticommutation relations (CAR). In a Fock representation ß P , Bogoliubov automorphisms
lead to irreducible representations. More precisely, the representation ß P ffi % U is again a Fock representation.
The unitary equivalence class of ß P ffi % U is...
16.
Kinetics of a Model Weakly Ionized Plasma in the Presence of Multiple Equilibria - E. Carlen,R. Esposito,J. L. Lebowitz,R. Marra
:
We study, globaly in time, the velocity distribution f(v; t) of a spatially homogeneous
system that models a system of electrons in a weakly ionized plasma,
subjected to a constant external electric field E. The density f satisfies a Boltzmann
type kinetic equation containing a full nonlinear electron-electron collision
term as well as linear terms representing collisions with reservoir particles having
a specified Maxwellian distribution. We show that when the constant in front
of the nonlinear collision kernel, thought of as a scaling parameter, is sufficiently
strong, then the L
1
distance between f and a certain time dependent Maxwellian
stays small uniformly in t. Moreover, the mean and variance...
17.
Performance Comparison Of Video Transport Over ATM ServerNet Interconnects - Ashfaq Hossain,Sung-mo Kang,Bob Horst
We have developed fully functional Video Server and Client applications which can transmit, receive, decompress
and display compressed video over various networks. Our video transport allows dynamic rate control
feedback, loss detection and repair request from Clients to the Server. Our experiments show how feedbackbefore
-degradation scheme for rate adaptation maintains desired QoS for video playback. We demonstrate
how the playback degradation occurs and what happens if corrective measures are not taken to improve the
situation. We attribute this degradation to increased internal kernel buffering which consumes scarce CPU
resource. While comparing the ATM performance of our video applications with that of ServerNet, we observe
that ServerNet,...
18.
The System Of Two Spinning Disks In The Torus. - Maciej P. Wojtkowski
.
We study the system of two spinning disks in the torus. We show how to reduce
this nonhamiltonian system to a 3 dimensional measure preserving reversible map. We
establish that, in contrast to the case of elastic collisions, this system may have periodic
orbits with all Floquet exponents on the unit circle.
We would like to thank Eugene Gutkin and Dave Levermore for helpful and enlightening discussions.
The suggestions of the referee are also gratefully acknowledged.
Typeset by A M S-T E X
x0.Introduction.
The Boltzman-Sinai system of hard balls, or two dimensional disks, moving in a
torus and colliding elastically is nonuniformly hyperbolic ([S], also [S-Ch] and [W1]).
In...
19.
Frames, Objects and Relations: Three Semantic Levels for Knowledge Base Systems - M. C. Norrie,U. Reimer,M. Rys
We propose an architecture for large-scale
knowledge base systems based on database
technologies and the three levels of semantic
construct - frames, objects and relations.
The intermediate object level retains
the structural semantics of the frame level
and is therefore beneficial in bridging the
semantic gap between the frame and relational
levels and enabling the use of semantic
information in query optimisation.
Specifically, we outline how this approach
has been adopted in the hybrid knowledge
base system, HYWIBAS.
1 Introduction
For knowledge base systems to be effective for largescale
applications, it is essential that they support
efficient retrieval and update operations on large,
shared knowledge bases. Database system research
has focussed on issues of performance and concurrent
access to...
20.
Optimizing ML with Run-Time Code Generation - Mark Leone,Peter Lee
We describe the design and implementation of a compiler that automatically translates ordinary
programs written in a subset of ML into code that generates native code at run time. Run-time
code generation can make use of values and invariants that cannot be exploited at compile time,
yielding code that is superior to statically optimal code. But the cost of optimizing and generating
code at run time can be prohibitive. We demonstrate how compile-time specialization can reduce
the cost of run-time code generation by an order of magnitude without greatly affecting code
quality. Several benchmark programs are examined, which exhibit an average cost of six cycles per
instruction...
1.
