12,621 research outputs found
Test item taxonomy based of functional criteria
There are many taxonomies that try to classify and apply some consistency to the very many item types currently in existence. They all have various limitations, however, such as ambiguous classification criteria, little discrimination between format types, and referring almost exclusively to pen-and-paper or screen-based items. This paper aims to overcome these limitations by proposing a new item format taxonomy based on functional criteria. Current classifications are reviewed, the criteria they are based on are examined and their limitations are identified. The proposed alternative classification identifies four essential components of items according to function: the structure of the included content, the device used for transmission of the question to the examinee, the device for receiving the response, and the instructions to the examinee about how to understand and respond to the item. The combination of different facets of these four components allows any format of item to be classified, both existing formats and those that may appear in the future. In addition to systematically and coherently classifying items, this new taxonomy may also be of great utility in the construction and research of new items. The proposed model is illustrated by examples showing how specific items are classified, using a checklist as a guide.Ministerio de Economía y Competitividad de España PSI2014-56114-PMinisterio de Economía y Competitividad de España PSI2017-85724-
A Topological-Based Method for Allocating Sensors by Using CSP Techniques
Model-based diagnosis enables isolation of faults of a system.
The diagnosis process uses a set of sensors (observations) and a model
of the system in order to explain a wrong behaviour. In this work, a
new approach is proposed with the aim of improving the computational
complexity for isolating faults in a system. The key idea is the addition of
a set of new sensors which allows the improvement of the diagnosability
of the system. The methodology is based on constraint programming
and a greedy method for improving the computational complexity of the
CSP resolution. Our approach maintains the requirements of the user
(detectability, diagnosability,. . .).Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
An Integration of FDI and DX Techniques for Determining the Minimal Diagnosis in an Automatic Way
Two communities work in parallel in model-based diagnosis:
FDI and DX. In this work an integration of the FDI and the DX communities
is proposed. Only relevant information for the identification of the
minimal diagnosis is used. In the first step, the system is divided into
clusters of components, and each cluster is separated into nodes. The
minimal and necessary set of contexts is then obtained for each cluster.
These two steps automatically reduce the computational complexity
since only the essential contexts are generated. In the last step, a signature
matrix and a set of rules are used in order to obtain the minimal
diagnosis. The evaluation of the signature matrix is on-line, the rest of
the process is totally off-line.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Adverbios de foco en griego antiguo: μόνον frente a μόνος en la prosa historiográfi ca clásica y helenística
The constructions of the adjective μόνος and the adverb μόνον as focalizers are investigated in the text of Thucydides and contrasted with the data from Herodotus and Polybius offered by Powell’s and Mauerberger’s lexica. Besides the identifi cation of those constructions, and in order to describe their syntactic and semantic properties, further aspects are investigated, namely: association with the negative, scope, position relative to the focused item, expression of an explicit alternative and focusing of an elided term.Se presenta un estudio de las construcciones del adjetivo μόνος y el adverbio μόνον como focalizadores en el texto de Tucídides, y posteriormente un contraste con los datos ofrecidos por Powell en su léxico de Herodoto y Mauersberger en su léxico polibiano. Aparte de la identifi cación de construcciones de foco y con objeto de describir sus propiedades sintácticas y semánticas, se investigan otros aspectos, a saber, la asociación con la negación, el alcance estructural, la posición relativa al elemento focalizado, la expresión de la alternativa y la construcción del adjetivo focalizando un término omitido
Diagnosing Errors in DbC Programs Using Constraint Programming
Model-Based Diagnosis allows to determine why a correctly
designed system does not work as it was expected. In this paper, we propose
a methodology for software diagnosis which is based on the combination
of Design by Contract, Model-Based Diagnosis and Constraint
Programming. The contracts are specified by assertions embedded in the
source code. These assertions and an abstraction of the source code are
transformed into constraints, in order to obtain the model of the system.
Afterwards, a goal function is created for detecting which assertions or
source code statements are incorrect. The application of this methodology
is automatic and is based on Constraint Programming techniques.
The originality of this work stems from the transformation of contracts
and source code into constraints, in order to determine which assertions
and source code statements are not consistent with the specification.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Applying Constraint Databases in the Determination of Potential Minimal Conflicts to Polynomial Model-Based Diagnosis
Model-based Diagnosis allows the identification of the parts
which fail in a system. The models are based on the knowledge of the
system to diagnose, and may be represented by constraints associated
to the components. The variables of these constraints can be observable
or non-observable, depending on the situation of the sensors. In order to
obtain the potential minimal diagnosis in a system, an important issue is
related to finding out the potential minimal conflicts in an efficient way.
We consider that Constraint Databases represent an excellent option in
order to solve this problem in complex systems.
In this work we have used a novel logical architecture of Constraint
Databases which has allowed obtaining these potential conflicts by means
of the corresponding queries. Moreover, we have considered Gröbner
Bases as a projection operator to obtain the potential minimal conflicts
of a system. The first results obtained on this work, which are shown in
a heat exchangers example, have been very promising.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Developing a labelled object-relational constraint database architecture for the projection operator
Current relational databases have been developed in order to improve the handling of
stored data, however, there are some types of information that have to be analysed for
which no suitable tools are available. These new types of data can be represented and treated
as constraints, allowing a set of data to be represented through equations, inequations
and Boolean combinations of both. To this end, constraint databases were defined and
some prototypes were developed. Since there are aspects that can be improved, we propose
a new architecture called labelled object-relational constraint database (LORCDB). This provides
more expressiveness, since the database is adapted in order to support more types of
data, instead of the data having to be adapted to the database. In this paper, the projection
operator of SQL is extended so that it works with linear and polynomial constraints and
variables of constraints. In order to optimize query evaluation efficiency, some strategies
and algorithms have been used to obtain an efficient query plan.
Most work on constraint databases uses spatiotemporal data as case studies. However,
this paper proposes model-based diagnosis since it is a highly potential research area,
and model-based diagnosis permits more complicated queries than spatiotemporal examples.
Our architecture permits the queries over constraints to be defined over different sets
of variables by using symbolic substitution and elimination of variables.Ministerio de Ciencia y Tecnología DPI2006-15476-C02-0
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