181 research outputs found
Data modeling dealing with uncertainty in fuzzy logic
This paper shows models of data description that incorporate uncertainty like models of data extension EER, IFO among others. These database modeling tools are compared with the pattern FuzzyEER proposed by us, which is an extension of the EER model in order to manage uncertainty with fuzzy logic in fuzzy databases. Finally, a table shows the components of EER tool with the representation of all the revised models.The past and the future of information systems: 1976-2006 and beyondRed de Universidades con Carreras en Informática (RedUNCI
A Knowledge Representation Example of a Fuzzy Database Implemented in PostgreSQL, with FIRST-2 and FSQL
In this article we present how to implement fuzzy databases based on the relational model. This approach includes many fuzzy attribute types, which can express the most of fuzzy knowledge types. These fuzzy attribute types include imprecise attributes, fuzzy attributes associated with one or more attributes, or with an independent meaning. In order to represent such fuzzy information we must study two aspects of fuzzy information: how to represent fuzzy data and how to represent fuzzy metaknowledge data. This second information is very important and it must be considered in any fuzzy database. This article studies the fuzzy metaknowledge data for any fuzzy attribute and how to represent both in a relational database. Finally, we apply all of this in a real example in the context of medical appointments.Sociedad Argentina de Informática e Investigación Operativ
Інфологічне моделювання інформаційної системи контролю витрат ресурсів
Інфологічне моделювання даних є невід’ємною складовою процесу розробки інформаційної системи контролю витрат ресурсів. Звичайні чіткі високорівневі моделі даних не дозволяють враховувати недосконалу інформацію, яка міститься в описі різних видів ресурсів та процесів їх використання. На основі аналізу видів недосконалої інформації системи розроблено узагальнену інфологічну модель шляхом розширення ER-моделі представленням нечітких атрибутів. Запропонована модель дозволяє одночасне представлення чітких та нечітких атрибутів сутностей та відношень і може бути використана при проектуванні даталогічної моделі даних з урахуванням особливостей виробничих процесів конкретного підприємства.Infological modeling of data is an integral part of the resource supervising information system developing process. Ordinary crisp high-level data models do not allow to consider the imperfect information contained in the description of various types of resources and their use processes. On the basis of the analysis of the system imperfect information types, a generalized infological model was developed by extending the ER-model with the representation of fuzzy attributes. The proposed model can allow the simultaneous presentation of crisp and fuzzy attributes of entities and relationships and can be used in datalogical modeling taking into account the features of the specific enterprise production processes
Data modeling dealing with uncertainty in fuzzy logic
This paper shows models of data description that incorporate uncertainty like models of data extension EER, IFO among others. These database modeling tools are compared with the pattern FuzzyEER proposed by us, which is an extension of the EER model in order to manage uncertainty with fuzzy logic in fuzzy databases. Finally, a table shows the components of EER tool with the representation of all the revised models.The past and the future of information systems: 1976-2006 and beyondRed de Universidades con Carreras en Informática (RedUNCI
COOPERATIVE QUERY ANSWERING FOR APPROXIMATE ANSWERS WITH NEARNESS MEASURE IN HIERARCHICAL STRUCTURE INFORMATION SYSTEMS
Cooperative query answering for approximate answers has been utilized in various problem domains. Many challenges in manufacturing information retrieval, such as: classifying parts into families in group technology implementation, choosing the closest alternatives or substitutions for an out-of-stock part, or finding similar existing parts for rapid prototyping, could be alleviated using the concept of cooperative query answering. Most cooperative query answering techniques proposed by researchers so far concentrate on simple queries or single table information retrieval. Query relaxations in searching for approximate answers are mostly limited to attribute value substitutions. Many hierarchical structure information systems, such as manufacturing information systems, store their data in multiple tables that are connected to each other using hierarchical relationships - "aggregation", "generalization/specialization", "classification", and "category". Due to the nature of hierarchical structure information systems, information retrieval in such domains usually involves nested or jointed queries. In addition, searching for approximate answers in hierarchical structure databases not only considers attribute value substitutions, but also must take into account attribute or relation substitutions (i.e., WIDTH to DIAMETER, HOLE to GROOVE). For example, shape transformations of parts or features are possible and commonly practiced. A bar could be transformed to a rod. Such characteristics of hierarchical information systems, simple query or single-relation query relaxation techniques used in most cooperative query answering systems are not adequate. In this research, we proposed techniques for neighbor knowledge constructions, and complex query relaxations. We enhanced the original Pattern-based Knowledge Induction (PKI) and Distribution Sensitive Clustering (DISC) so that they can be used in neighbor hierarchy constructions at both tuple and attribute levels. We developed a cooperative query answering model to facilitate the approximate answer searching for complex queries. Our cooperative query answering model is comprised of algorithms for determining the causes of null answer, expanding qualified tuple set, expanding intersected tuple set, and relaxing multiple condition simultaneously. To calculate the semantic nearness between exact-match answers and approximate answers, we also proposed a nearness measuring function, called "Block Nearness", that is appropriate for the query relaxation methods proposed in this research
Geosimulation and Multicriteria Modelling of Residential Land Development in the City of Tehran: A Comparative Analysis of Global and Local Models
Conventional models for simulating land-use patterns are insufficient in addressing complex dynamics of urban systems. A new generation of urban models, inspired by research on cellular automata and multi-agent systems, has been proposed to address the drawbacks of conventional modelling. This new generation of urban models is called geosimulation. Geosimulation attempts to model macro-scale patterns using micro-scale urban entities such as vehicles, homeowners, and households. The urban entities are represented by agents in the geosimulation modelling. Each type of agents has different preferences and priorities and shows different behaviours. In the land-use modelling context, the behaviour of agents is their ability to evaluate the suitability of parcels of land using a number of factors (criteria and constraints), and choose the best land(s) for a specific purpose. Multicriteria analysis provides a set of methods and procedures that can be used in the geosimulation modelling to describe the behaviours of agents.
There are three main objectives of this research. First, a framework for integrating multicriteria models into geosimulation procedures is developed to simulate residential development in the City of Tehran. Specifically, the local form of multicriteria models is used as a method for modelling agents’ behaviours. Second, the framework is tested in the context of residential land development in Tehran between 1996 and 2006. The empirical research is focused on identifying the spatial patterns of land suitability for residential development taking into account the preferences of three groups of actors (agents): households, developers, and local authorities. Third, a comparative analysis of the results of the geosimulation-multicriteria models is performed. A number of global and local geosimulation-multicriteria models (scenarios) of residential development in Tehran are defined and then the results obtained by the scenarios are evaluated and examined. The output of each geosimulation-multicriteria model is compared to the results of other models and to the actual pattern of land-use in Tehran. The analysis is focused on comparing the results of the local and global geosimulation-multicriteria models. Accuracy measures and spatial metrics are used in the comparative analysis. The results suggest that, in general, the local geosimulation-multicriteria models perform better than the global methods
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The interpretation and use of numerically-quantified expressions
This thesis presents a novel pragmatic account of the meaning and use of numerically-quantified expressions. It can readily be seen that quantities can typically be described by
many semantically truthful expressions – for instance, if "more than 12" is true of a quantity,
so is "more than 11", "more than 10", and so on. It is also intuitively clear that some of these
expressions are more suitable than others in a given situation, a preference which is not
captured by the semantics but appears to rely upon on wider-ranging considerations of
communicative effectiveness.
Motivated by these observations, I lay out a set of criteria that are demonstrably relevant to
the speaker's choice of utterance in such cases. Observing further that it is typically
impossible to satisfy all these criteria with a single utterance, I suggest that the speaker's
choice of utterance can be construed as a problem of multiple constraint satisfaction. Using
the formalism of Optimality Theory (Prince and Smolensky 1993), I proceed to specify a
model of speaker behaviour for this domain of usage.
The model I propose can be used to draw predictions both about the speaker's choice of
utterance and the hearer's interpretation of utterances. I discuss the relation between these
two aspects of the model, showing how constraints on the speaker's choice of utterance are
predicted to make pragmatic enrichments available to the hearer. I then consider applications
of this idea to specific issues that have been discussed in the literature. Firstly, with respect
to superlative quantifiers, I show how this model provides an alternative account to that of
Geurts and Nouwen (2007), building upon that offered by Cummins and Katsos (2010), and I
present empirical evidence in its favour. Secondly, I show how this model yields the novel
prediction that comparative quantifiers give rise to implicatures that are conditioned both by
granularity and by prior mention of the numeral, and demonstrate these implicatures
empirically. Finally I discuss the predictions that the model makes about the frequency of
quantifiers in corpora, and investigate their validity.
I conclude that the model presented here proves its worth as a source of hypotheses about
speaker and hearer behaviour in the numerical domain. In particular, it serves as a way to
integrate insights from distinct domains of enquiry including psycholinguistics, theoretical
semantics and numerical cognition. I discuss the claim of this model to psychological
plausibility, its relation to existing approaches, and its potential utility when applied to
broader domains of language use.This work was supported by a University of Cambridge (Trinity College) Domestic Research Studentship
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