• Structural Engineering and Mechanics
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• v.25 no.5
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• pp.501-518
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• 2007

In this work, a new approach is developed for dynamic analysis of a composite beam with an interply crack, based on finite element solution of partial differential equations with the use of the COMSOL Multiphysics package, allowing for fast and simple change of geometric characteristics of the delaminated area. The use of COMSOL Multiphysics package facilitates automatic mesh generation, which is needed if the problem has to be solved many times with different crack lengths. In the model, a physically impossible interpenetration of the crack faces is prevented by imposing a special constraint, leading to taking account of a force of contact interaction of the crack faces and to nonlinearity of the formulated boundary value problem. The model is based on the first order shear deformation theory, i.e., the longitudinal displacement is assumed to vary linearly through the beam's thickness. The shear deformation and rotary inertia terms are included into the formulation, to achieve better accuracy. Nonlinear partial differential equations of motion with boundary conditions are developed and written in the format acceptable by the COMSOL Multiphysics package. An example problem of a clamped-free beam with a piezoelectric actuator is considered, and its finite element solution is obtained. A noticeable difference of forced vibrations of the delaminated and undelaminated beams due to the contact interaction of the crack's faces is predicted by the developed model.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.46-53
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• 2007

In this paper, a guidance law for vision-based automatic landing of unmanned aerial vehicles (UAVs) is proposed. Automatic landing is a challenging but crucial capability for UAVs to achieve a fully autonomous flight. In an autonomous landing maneuver of UAVs, the decision of where to landing and the generation of guidance command to achieve a successful landing are very significant problem. This paper is focused on the design of guidance law applicable to automatic landing problem of fixed-wing UAV and rotary-wing UAV, simultaneously. The proposed guidance law generates acceleration command as a control input which derived from a specified time-to-go ($t_go$) polynomial function. The coefficient of $t_go$-polynomial function are determined to satisfy some terminal constraints. Nonlinear simulation results using a fixed-wing and rotary-wing UAV models are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.212-219
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• 2006

The important problem in designing a Fuzzy Logic Controller(FLC) is generation of fuzzy control rules and it is usually the case that they are given by human experts of the problem domain. However, it is difficult to find an well-trained expert to any given problem. In this paper, I describes an application of genetic algorithm, a well-known global search algorithm to automatic generation of fuzzy control rules for FLC design. Fuzzy rules are automatically generated by evolving initially given fuzzy rules and membership functions associated fuzzy linguistic terms. Using genetic algorithm efficient fuzzy rules can be generated without any prior knowledge about the domain problem. In addition expert knowledge can be easily incorporated into rule generation for performance enhancement. We experimented genetic algorithm with a non-trivial vehicle controling problem. Our experimental results showed that genetic algorithm is efficient for designing any complex control system and the resulting system is robust.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.865-872
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• 2013

Two-level morphology analysis method is one of rule-based morphological analysis method. This approach handles morphological transformation using rules and analyzes words with morpheme connection information in a lexicon. It is independent of language and Korean Two-level system was also developed. But, it was limited in practical use, because of using very small set of lexicon built manually. And it has also a over-generation problem. In this paper, we propose an automatic construction method of Korean Two-level lexicon for PC-KIMMO from morpheme tagged corpus. We also propose a method to solve over-generation problem using lexical information and sub-tags. The experiment showed that the proposed method reduced over-generation by 68% compared with the previous method, and the performance increased from 39% to 65% in f-measure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.748-753
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• 2005

Among processes to manufacture parts from footwear materials like upper leathers, one of the most essential processes is the cutting one optimally arranging lots of parts on raw footwear materials and cutting. A new nesting strategy was proposed for the 2-dimensional part layout by using a two-stage approach, where which can be effectively used for water jet cutting. In the initial layout stage, a SOAL(Self-Organization Assisted Layout) based on the combination of FCM(Fuzzy C-Means) and SOM was adopted. In the layout improvement stage, SA(Simulated Annealing) based approach was adopted for a finer layout. The proposed approach saves much CPU time through a two-stage approach scheme, while other annealing-based algorithm so far reported fur a nesting problem are computationally expensive. The proposed nesting approach uses the stochastic process, and has a much higher possibility to obtain a global solution than the deterministic searching technique. We developed the automatic nesting software of NST(ver.1.1) software for footwear industry by implementing of these proposed algorithms. The NST software was applied by the optimized automatic arrangement algorithm to cut without the loss of leathers. if possible, after detecting damage areas. Also, NST software can consider about several features in not only natural loathers but artificial ones. Lastly, the NST software can reduce a required time to implement generation of NC code. cutting time, and waste of raw materials because the NST software automatically performs parts arrangement, cutting paths generation and finally NC code generation, which are needed much effect and time to generate them manually.

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.41-46
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• 2015

This paper describes study results on the development of an automatic program for generating surface-panel grid for the aircraft optimal design. The aerodynamic analysis is combined into a PIDO tool in conjunction with a number of programs in order to integrate processes for the optimal design. Due to design optimization's iterative feature, it may require lots of time and cost. To relieve this problem, cost-reduction of computation time for aerodynamic analysis is pursued by using the Panel-method, and reduction of grid generation time by automating surface panelling.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.2
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• pp.91-102
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• 2012

Computer aided language learning has become popular. But the level of automation of constructing a Korean learning assistant system is not so high because a practical language learning system needs large scale knowledge resources, which is very hard to acquire. In this paper, we propose a Korean learning assistant system that utilizes easily obtainable knowledge resources like a corpus, web documents and a lexicon. Our system has three modules - problem solving, pronunciation marker and writing assistant. Automatic problem generator uses a corpus and a lexicon to make problems with one correct answer and three distracters, then verifies their suitability by utilizing frequency information from web documents. We analyze pronunciation rules for a pronunciation marker and recommend appropriate words and sentences in real-time by using data extracted from a corpus. In experiment, we evaluate 400 automatically generated problems, which show 89.9% problem suitability and 64.9% example suitability.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.1-9
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• 2010

This paper proposes a test method for compliance of SMS encoder and decoder modules with 3GPP (3rd Generation Partnership Project) specification on SMS PDU (Protocol Data Unit). The existing tools have focused on providing an SMS gateway and on helping to view and edit a single SMS PDU, which rarely help to resolve the compliance test problem. The proposed compliance test method is based on an automatic generation of SMS PDUs fully compliant with the 3GPP specification by using QuickCheck library written in Haskell. By applying the proposed method to a C-based SMS encoder and decoder in Linux Mobile platform, we have found out several critical bugs such as wrong interpretation of time stamps in BCD format. The automatic SMS PDU generator is reusable in that it only depends on the 3GPP SMS specification. The QuickCheck library is also applicable for testing other network protocol data encoders and decoders, as used in this paper.

• Asia pacific journal of information systems
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• v.13 no.1
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• pp.213-230
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• 2003

Most of existing expert systems developed for Web use CGI-based techniques and this frequently makes them suffer from the overburden of commercial Web servers, which deal with large-scale services. However, since HTML-based inference technique represents expert's knowledge by hyperlinks among HTML documents, the hypertext function of the Web can perform the inference efficiently in terms of time and space without the help of additional inference engines. In spite of such benefits, when the expert's knowledge is relatively large and/or complicated, the HTML-based inference technique has usually become to have a hard time of dealing with a lot of HTML documents because generation and management tasks of the numerous HTML documents would cause big trouble to the knowledge engineer. To resolve this problem, we developed an automatic generation and management tool for Web-based inference sites, called WeBIS. With this tool, a knowledge engineer can input and edit expert's knowledge using Expert's Diagram on the GUI(Graphical User Interface) environment and automatically generate hyper-linked HTML documents for Web-based inference from the Expert's Diagram.

• Journal of Information Technology and Architecture
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• v.9 no.4
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• pp.357-363
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• 2012

Ontologies are being used in order to define common vocabularies to describe the elements of schemas involved in a particular application. The problem of finding correspondences between ontologies concepts, called ontology matching, consists in the discovery of correspondences between terms of vocabularies (represented by ontologies) used by various applications. The majority of solutions proposed in the literature, despite being fully automatic, has heuristic nature and may produce nonsatisfactory results. The problem intensifies when dealing with large data sources. The goal of this paper is to propose a method for generation and incremental refinement of correspondences between ontologies. The proposed approach uses filtering techniques, as well as user feedback to support the generation and refinement of such matches. For validation purposes, a tool was developed and some experiments were conducted.