Hybrid Representation Scheme Research Articles

Efficient features for smartphone-based iris recognition

Iris recognition has widely been used in personal authentication problems. Recent advances in iris recognition through visible wavelength images have paved the way for the use of this technology in smartphones. Smartphone-based iris recognition can be of significant use in financial transactions and secure storage of sensitive information. This paper presents a hybrid representation scheme for iris recognition in mobile devices. The scheme is called hybrid because it firstly makes use of Gabor wavelets to reveal the texture present in the normalized iris images, and then extracts statistical features from different partitions of Gabor-processed images. The standard mobile-iris database, called MICHE, is used for investigating the performance of the proposed approach. The comparison of the proposed approach with other widespread iris recognition approaches proves its efficacy.

HYBRID REPRESENTATION OF SOLIDS USING IMPLICIT AND PARAMETRIC FUNCTIONS

Context. The present article deals with the problem of representation of solids in computer-aided design. The object of the study is a process of representation of solids in computer-aided design. Objective. The objective of the study is the development of a hybrid representation scheme which uses implicit functions, Roperations and parametric functions. Method. In the article, a hybrid representation scheme has been suggested to model solids. An abstract notion “solid” denotes bounded and closed subsets of Euclidean space, which model physical bodies. A representation scheme is a syntactically and semantically correct relation between a set of formal models and a set of solids. It is supposed that boundary represented regions are defined by parametric functions. On the other hand, functionally represented regions are defined by implicit functions. The hybrid representation scheme is based on an idea of combining the boundary representation scheme with the functional representation scheme. The hybrid representation scheme uses a signed distance function to transform regions with parametric boundaries into implicitly defined regions. Adaptive discrete models are used to evaluate a signed distance from some point to a boundary of a region which boundaries are defined by parametric functions. A distance from a point to the closest discrete element approximates a distance from a point to a boundary of a region. The parity test has been used to define a sign of a distance. Results. The developed hybrid representation scheme has been implemented in software and investigated for solving the problems of solid modeling. Conclusions. Carried out numerical experiments have confirmed the proposed software operability. The prospects for further research may include the development of parallel methods for calculation of a signed distance function

COMPUTER GRAPHICS AND GEOMETRIC MODELLING -- A HYBRID APPROACH

The present paper describes an approach to geometric modelling, in which the representation of solids is hybrid and consists of an easily expand- able collection of representations. We also consider an experimental prototype of a framework for the development of systems for geometric modelling based on open hybrid representation schemes. We present a method for creating software-hardware (hybrid) systems based on this approach.

Representation of Argumentation in Text with Rhetorical Structure Theory

Various argumentation analysis tools permit the analyst to represent functional components of an argument (e.g., data, claim, warrant, backing), how arguments are composed of subarguments and defenses against potential counterarguments, and argumentation schemes. In order to facilitate a study of argument presentation in a biomedical corpus, we have developed a hybrid scheme that enables an analyst to encode argumentation analysis within the framework of Rhetorical Structure Theory (RST), which can be used to represent the discourse structure of a text. This paper describes the hybrid representation scheme and illustrates its use for investigation of contexts that license omission of elements of an argument. The analyses given in the paper involve reconstruction of enthymemes. Defeasible argumentation schemes serve as a constraint on reconstruction. In addition, the examples illustrate several other types of contextual constraints on reconstruction of enthymemes.

Hybrid knowledge representation in a blackboard KBS for liquid retaining structure design

This paper highlights the importance of design expertise, for designing liquid retaining structures, including subjective judgments and professional experience. Design of liquid retaining structures has special features different from the others. Being more vulnerable to corrosion problem, they have stringent requirements against serviceability limit state of crack. It is the premise of the study to transferring expert knowledge in a computerized blackboard system. Hybrid knowledge representation schemes, including production rules, object-oriented programming, and procedural methods, are employed to express engineering heuristics and standard design knowledge during the development of the knowledge-based system (KBS) for design of liquid retaining structures. This approach renders it possible to take advantages of the characteristics of each method. The system can provide the user with advice on preliminary design, loading specification, optimized configuration selection and detailed design analysis of liquid retaining structure. It would be beneficial to the field of retaining structure design by focusing on the acquisition and organization of expert knowledge through the development of recent artificial intelligence technology.

Application of Fuzzy Set Theory to Setup Planning

Computer-aided process planning and computer-aided fixture planning have been widely researched in the last two decades. Most of these computer-aided systems are, however, either dealing only with process planning or fixture design. This paper advocates set-up planning as a link between these two functions. A set-up planning system for the machining of prismatic parts on a 3-axis vertical machining centre is proposed. This system formulates set-up plans based on the initial, intermediate and final states of a part. The system uses the fuzzy set representation, along with production rules and object representation. This hybrid representation scheme aptly depicts the inexact relationships among features required on a final part, and with those currently present on the part These inexact relationships, which greatly affect set-up planning, are manifestations of the various process and fixture planning constraints in the system. The consideration of these features' relationships together with the intermediate states of a part, allow the system to plan forward without the need to backtrack. Through this representation, the set-up planning problem is formulated using the fuzzy set theory. Using this approach, the proposed system is able to generate set-ups that fulfil the process and fixture planning requirements that are commonly practised by experienced planners.

Decision support for drug prescription integrated with computer-based patient records in primary care.

A conceptual model of an information system that integrates a controlled vocabulary, a patient database, and a knowledge base is described. Methods, design and components for the implementation of the system are discussed. It is argued that the key issue for the successful introduction of computer-based decision support in primary care today is integration with a computer-based patient record. Also important is that the knowledge acquisition process is based on the general practitioner's real needs. This has been achieved by, first, providing general practitioners with real patient data from a series of retrospective database studies; and second, letting a panel of general practitioners select, discuss and decide which computer reminders to implement. A hybrid representation scheme was chosen for the knowledge base. The combination of a standard procedural representation (the so-called Arden syntax) for the reminder knowledge with a semantic net representation for the medical factual knowledge facilitates knowledge sharing with other systems and knowledge reuse within the system.

An analog circuit design environment based on cooperating blackboard systems

A novel approach to design automation for analog circuits is presented. The prototype implementation-OASE-has been realized as a set of cooperating expert systems with blackboard architecture. The circuit specific knowledge bases use hybrid representation schemes and are strictly separated from an execution engine containing the necessary control knowledge. This alleviates the knowledge acquisition process as well as the extension and maintenance of existing knowledge. OASE has been developed as a design assistant, featuring different levels of interactivity, a hierarchical design style and fully embedded algorithmic standard tools. In its current version it is able to design a broad range of different CMOS operational amplifiers.

Knowledge representation in expert systems for process control

The application of so-called “higher automation functions” in complex systems is usually connected with considerable difficulties. In most cases these automation tasks can satisfactorily be solved only by the help of a suitable decision support system. Considering the knowledge base in process automation a special framework for knowledge representation in XPS for process control and an original inference strategy will be discussed. Features of quality and demands on knowledge representation components in real-time expert systems are formulated. The advantages of hybrid representation schemes utilizing algorithmic (deep) knowledge mainly in the procedural part of the knowledge base are pointed out. The presented solution was introduced developing the real-time expert system shell PROCON.

Interactive multicriteria linear programming: An extension of the method of Zionts and Wallenius

This article presents an extension of the interactive multicriteria linear-programming method of Zionts and Wallenius [see Management Science, 29(5) (1983)]. The decision maker's underlying utility function is assumed to be pseudoconcave, and his preference structure is assessed through pairwise comparison questions. In the method of Zionts and Wallenius, the decision maker's preference structure is represented as constraints on the weights on the objectives derived from his responses. This representation is only a linear approximation to the underlying nonlinear utility function. Accordingly, inconsistency among the constraints on the weights arises while solving the problem. Therefore, some of the constraints have to be dropped, resulting in a loss of information on the preference structure, and hence an increase in the total number of questions. In this article we develop a hybrid representation scheme to avoid this problem. The proposed scheme is implemented within the algorithmic framework of the method of Zionts and Wallenius, and its underlying theory is developed. Computational results show that the number of questions required by the Zionts and Wallenius method can be sinificantly reduced using the proposed scheme.

Verification of conceptual schemata based on hybrid object-oriented and logic paradigm

Contemporary conceptual modelling languages are concerned with the representational adequacy of knowledge about a universe of discourse and with the efficient organization of this knowledge in structures that help overcome the problems of size and complexity in the modelled reality. In the paper it is argued that a conceptual modelling language should also facilitate the verification of captured requirements by exercising the conceptual schemata derived from the use of such a language. A conceptual modelling language is presented that is based on a hybrid representation scheme that makes use of object-oriented and logic approaches, and it is shown how this language can be used to verify requirements during the development of information systems.