Construction of Fuzzy Ontology-Based Terrorism Event Extraction

Ontologies now play an important role for many knowledge-intensive applications for which they provide a way to describe and structure the information on the web. Fuzzy ontologies extend the representation ability of traditional ontologies to handle fuzzy concepts. However, heterogeneity between ontologies still need to be solve, as current ontology mapping technologies are not sufficient for fuzzy ontologies. For the task of detecting and retrieving relevant ontologies, this paper proposes an approach to measure concept similarity between fuzzy ontologies. It applies the fuzzy sets to represent fuzzy concepts, and evaluates the concept similarity by their common characters of linguistics, fuzzy set, super-concepts, sub-concepts, instances and properties.

This paper proposes a novel extension of blockchain systems with fuzzy ontologies. The main advantage is to let the users have flexible restrictions, represented using fuzzy sets, and to develop smart contracts where there is a partial agreement among the involved parts. We propose a general architecture based on four fuzzy ontologies and a process to develop and run the smart contracts, based on a reduction to a well-known fuzzy ontology reasoning task (Best Satisfiability Degree). We also investigate different operators to compute Pareto-optimal solutions and implement our approach in the Ethereum blockchain.

Fuzzy concepts are represented by fuzzy sets, so a fuzzy knowledge is defined to be a collection of fuzzy sets (concepts) which includes two constants, 1 (true) and 0 (false). Abstractly, a logical derivation is a finite series of logical operations acting on a given knowledge. In fuzzy world, logical operations are defined by mathematical operations. So fuzzy logical derivations are mathematical derivations, and vice versa In this paper, the closure of fuzzy reasoning is characterized by fuzzy rough sets, and by topologies (neighborhood systems). A new fuzzy concept F N is derivable from the old knowledge K iff the membership function of F N is continuous in K-topology, or equivalently, iff F N is a rough fuzzy set (concept) of I N D(K),or plainly, iff the membership function of F N is a “step” function in the sense that it takes a constant value in each equivalence class of I N D(K).A fuzzy set L partitions the universe into equivalence classes; each equivalence class consists of those elements which have the same degree of membership. The indiscernibility relation I N D(K)over K is the “intersection” of all the equivalence relations induced by the fuzzy sets in K. The membership function of a fuzzy set is a real valued function, so U can be given the minimal topology such that the membership function of each fuzzy set in K is a continuous function. Such topology is called K-topology.

How to quickly and cheaply construct Web ontologies has become a key technology to enable the Semantic Web. Classical ontologies are not sufficient for handling imprecise and uncertain information that is commonly found in many application domains. In this paper, we propose an approach for constructing fuzzy ontologies from fuzzy UML models, in which the fuzzy ontology consists of fuzzy ontology structure and instances. Firstly, the fuzzy UML model is investigated in detail, and a kind of formal definition of fuzzy UML models is proposed. Then, a kind of fuzzy ontology called fuzzy OWL DL ontology is introduced. Furthermore, we consider the fuzzy UML model and the corresponding fuzzy UML instantiations (i.e., object diagrams) simultaneously, and translate them into the fuzzy ontology structure and the fuzzy ontology instances, respectively. In addition, since a fuzzy OWL DL ontology is equivalent to a fuzzy Description Logic f-SHOIN(D) knowledge base, how the reasoning problems of fuzzy UML models (e.g., consistency, subsumption, equivalence, and redundancy) may be reasoned through reasoning mechanism of f-SHOIN(D) is investigated, which can help to construct fuzzy ontologies more exactly.

Construction of fuzzy ontologies from fuzzy XML models

Nowadays, there are a lot of ontology construction methods, but they cannot express ontology clearly. In this paper, we compare the existing ontology construction methods and then summarize the advantages and disadvantages of these methods. Unlike previous work, we focus our attention on the fuzzy ontology and propose a semi-automatic method for constructing fuzzy domain ontology. Then we apply it to guide the crawler in sorting the web pages in the shipping field. The experimental results show that our method has a better effect on the ranking of web pages.

How to construct Web ontologies that meet applications’ needs has become a key technology to enable the Semantic Web. Manual development of ontologies remains a cumbersome and time-consuming task. In real-world applications, however, information is often vague or ambiguous. Thus, developing approaches and tools for constructing fuzzy ontologies by extracting domain knowledge from huge amounts of existing fuzzy databases can facilitate fuzzy ontology development. In this paper, we propose a formal approach and an automated tool for constructing fuzzy ontologies from fuzzy Object-Oriented database (FOOD) models. Firstly, we introduce the fuzzy ontology, which consists of the fuzzy ontology structure and instances. Then, the FOOD models are investigated, and we propose a kind of formal definition of FOOD models. On this basis, we develop a formal approach that can translate the FOOD model and its corresponding database instances into the fuzzy ontology structure and the fuzzy ontology instances, respectively. Furthermore, following the proposed approach, we implement an automated learning tool, which can automatically construct fuzzy ontologies from FOOD models. Case studies show that the approach is feasible and the automated learning tool is efficient.

Ontologies represent a method of formally expressing a shared understanding of information, and have paved the way for sharing concepts across applications in an unambiguous way. However, these ontologies are assumed to be hand-crafted, pre-defined structures with crisp concept descriptions and inter-concept relations. Crisp definitions however are not sufficient for real-world applications like ontology-based information extraction from unstructured text. In this paper we propose an enhancement of the ontology structure to a fuzzy ontology, which provides a mechanism to store imprecise concept definitions. The proposed fuzzy ontology framework can also help in ascertaining similarities and dissimilarities of concept definitions across distributed ontologies representing the same domain. Our design of fuzzy ontology is motivated by fuzzy set theoretic representation and reasoning, and is entirely different from other fuzzy ontology designs, which use only co-occurrence of concepts to determine their closeness. We have cited examples from various domains to show the necessity and capability of the structure in representing real-world knowledge.

Ontology learning has become a popular research field recently. However, the typical ontology may not be sufficient to represent uncertainty information. Fuzzy ontology is proposed to solve the uncertainty reasoning problems. But the construction of fuzzy ontology is still a tedious and painstaking task. The cognitive model of fuzzy ontology learning is an automatic model of fuzzy ontology construction that simulates the process of human being recognizing the world. Induction is an important step of the model. In this paper, we present a strategy for the fuzzy ontology induction in the cognitive model of ontology learning which includes some generalization principles and the corresponding induction operators. It generates induction hypothesis through a series of operations. As a result, induction hypothesis are generated from the present ontology and it can generalize the existing ontology.

The fuzzy set concept is often used in solution of problems in which the initial data is difficult or impossible to represent in the form of specific numbers or sets. Geo-information objects are distinguished by their uncertainty, their characteristics are often vague and have some error. Therefore, in the study of such objects is introduced the concept of "fuzziness" — fuzzy sets, fuzzy logic, linguistic variables, etc. The fuzzy set concept is given in the form of membership function. An ordinary set is a special case of a fuzzy one. If we consider a fuzzy object on the map, for example, a lake that changes its shape depending on the time of year, we can build up for it a characteristic function from two variables (the object’s points coordinates) and put a certain number in accordance with each point of the object. That is, we can describe a fuzzy set using its two-dimensional graphical image. Thus, we obtain an approximate view of a surface z = μ(x, y) in three-dimensional space. Let us now draw planes parallel to the plane. We’ll obtain intersections of our surface with these planes at 0 ≤ z ≤ 1. Let's call them as isolines. By projecting these isolines on the OXY plane, we’ll obtain an image of our fuzzy set with an indication of intermediate values μ(x, y) linked to the set’s points coordinates. So we’ll construct generalized Euler — Venn diagrams which are a generalization of well-known Euler — Venn diagrams for ordinary sets. Let's consider representations of operations on fuzzy sets A a n d B. Th e y u s u a l l y t a k e : μA B = min (μA,μB ), μA B = max (μA,μB ), μA = 1 − μA. Algebraic operations on fuzzy sets are defined as follows: μ A B x μ A x μ B x ( ) = ( ) + ( ) − −μ A (x)μ B (x), μ A B x μ A x μ B x ( ) = ( ) ( ), μ A (x) = 1 − μ A (x). Let's construct for a particular problem a generalized Euler — Venn diagram corresponding to it, and solve subtasks graphically, using operations on fuzzy sets, operations of intersection and integrating of the diagram’s bars.

Ontology is the basis of sharing and reusing knowledge on the Semantic Web, and ontology-based semantic retrieval is a hotspot of current research. Fuzzy ontology is an extension of domain ontology for solving the uncertainty problems. To represent fuzzy knowledge more effectively, this paper presents a new series of fuzzy ontology models that consists of fuzzy domain ontology and fuzzy linguistic variable ontologies, considering semantic relationships of concepts, including set relation, order relation, equivalence relation and semantic association relation etc. The process to construct linguistic variables ontology is discussed. Using ontology and RDFS, the knowledge model for product information is created. To achieve semantic retrieval, the semantic query expansion in SeRQL is constructed by semantic relations between fuzzy concepts. The application shows that these models can overcome the localization of other fuzzy ontology models, and this research facilitates the fuzzy knowledge sharing and semantic retrieval on the Semantic Web.

Fuzzy Description Logics generalize crisp ones by providing membership degree semantics for concepts and roles by fuzzy sets. Recently, answering of conjunctive queries has been investigated and implemented in optimized reasoner systems based on the rewriting approach for crisp DLs. In this paper we investigate how to employ such existing implementations for crisp query answering in \(DL\text {-}Lite_{R}\) over fuzzy ontologies. To this end we give an extended rewriting algorithm for the case of fuzzy \(DL\text {-}Lite_{R}\)-ABoxes that employs the one for crisp \(DL\text {-}Lite_{R}\) and investigate the limitations of this approach. We also tested the performance of our proto-type implementation FLite of this method.

This paper presents a common framework for the conceptual information of MPEG-7, interoperable with the semantic Web, and providing high performance search capabilities, using fuzzy set theory and ontology relations. Starting from the meta-data model of the MPEG-7, to which we add few layers while keeping the existent, so as to guarantee compatibility with the standard, we then link MPEG-7 descriptions to ontologies. These ontologies are used to define precisely each element used in the description scheme of MPEG-7. In order to allow similarities estimations and performing searches, the model is projected into a 5-dimensional space that permits to describe easily the content of multimedia documents.

Ontology is adopted as a standard for knowledge representation on the Semantic Web, and Resource Description Framework (RDF) is used to add structure and meaning to Web applications. In order to incorporate fuzzy systems into the Semantic Web, this paper utilizes fuzzy ontology to represent formally the fuzzy linguistic variables, considering the semantic relationships between fuzzy concepts. Then fuzzy rule is described as a RDF resource with properties: “IF” and “THEN”, and rule's antecedent and consequent is represented in RDF statement. Taking the fuzzy control system of industrial washing machine for example, the fuzzy system with ontology and RDF is built, which shows that this research enables distributed fuzzy applications on the Semantic Web.

Obesity has a tight relationship with increased risks of different cancer types, such as Colorectal, Ovarian, Female Breast, Gallbladder, Adenocarcinoma, Kidney (Renal-Cell), Liver, and Pancreatic. It can also lead to some other diseases like diabetes and heart diseases. This paperproposes a fuzzy ontology that is based on OWL 2to represent the Obesity Related Cancer (ORC) domain knowledge. The diseases taxonomy isconstructed using the standard Disease Ontology. The presented FuzzyOntology includes more concepts than in crisp one and copes with the domain linguistic variables. It allows the users to query the Fuzzy Dl reasoner for element and get them back the fuzzy ontology for that element. It is expected to be good practice for ontologists and knowledge engineers in medical field aiding them to solve the overlapping concepts, linguistic variables, and reasoning problems by building their fuzzy ontologies. Building FOORC as an open ontology is a first attempt to organize information related to the obesity and cancer diseases in a formalized, structured manner that both physicians and intelligent systems can exploit it in knowledge sharing, reusability, and reasoning.