• International Journal of Aeronautical and Space Sciences
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• v.14 no.3
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• pp.264-271
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• 2013

A method of multiple transport-aircraft mission modeling is proposed in order to improve the efficiency of evaluating and optimizing pre-mission plans. To deal with the challenge of multiple transport-aircraft missions, the object-oriented modeling method is utilized. The elements of the mission are decomposed into objects and businesses, And the major mission objects and their important properties are summarized. A complex mission can be broken down into basic business modules such as the ground section and flight section. The business models of loading and fueling services in the ground section are described. The business model of the flight section is composed of an air route and flight profile with the flight equation and the fuel consumption model. The logical relationship of objects and business modules is introduced. The architecture of the simulation system, which includes a database, computation module, graphical user interface (GUI) module, and a result analysis module, is established. A sample case that includes two different plans is provided to verify the model's ability to achieve multi-aircraft composite mission simulation.

• Knowledge Management Research
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• v.7 no.2
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• pp.53-68
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• 2006

Knowledge has become an important resource for organization. The manufacturing industry is usually operated on the basis of business processes, and most workers are familiar with their own processes. The process-based approach, therefore, can provide an efficient way to capture and navigate knowledge. In this study, we focus on knowledge which may be missed during knowledge transfer among workers. For this, we propose a method for analyzing knowledge flow, which is passed among business processes. We propose a process-based knowledge management framework for analyzing knowledge flow, which employs a two-phase analysis: process analysis and knowledge flow analysis. A knowledge flow model, represented by Knowledge Flow Diagram, is proposed as a tool for representing knowledge. We formulate several semantics for knowledge flow modeling. We build the three-level schema: conceptual, logical, and physical in order to automate the knowledge model adaptive to knowledge management systems. The proposed approach is verified and illustrated through a case study on the manufacturing process of A Company.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.44-49
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• 2007

Recent manufacturing system requires development on new production technology to enable prompt manufacturing of diverse products. Most of the researchers have been working on micro-factory. Especially, focus on manufacturing of micro parts. Present manufacturing system consumes excessive resources in the form of energy and space to manufacture the micro parts. In this study, the micro lens module assembly system was modeled, analyzed with MST(Micro System Technology) Application Module and simulated through UML Language (Unified Modeling Language) with object-oriented logical model analysis method. Digital model of micro-factory was modeled, to execute the new paradigm of digitalization on products, resources and processes of micro-factory.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.1
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• pp.88-96
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• 1989

General measure in the reliability is the k-terminal reliability, which is the probability that the specified vertices are connected by the working edges. To compute the k-terminal reliability components are usually assumed to be statistically independent. In this study the modeling and analysis of the k-terminal reliability are investigated when dependency among components is considered. As the size of the network increases, the number of the joint probability parameter to represent the dependency among components is increasing exponentially. To avoid such a difficulty the structured-event-based-reliability model (SERM) is presented. This model uses the combination of the network topology (physical representation) and reliability block diagram (logical representation). This enables us to represent the dependency among components in a network form. Computational algorithms for the k-terminal reliability in SERM are based on the factoring algorithm Two features of the ractoring algorithm are the reliability preserving reduction and the privoting edge selection strategy. The pivoting edge selction strategy is modified by two different ways to tackle the replicated edges occuring in SERM. Two algorithms are presented according to each modified pivoting strategy and illustrated by numerical example.

• Management Science and Financial Engineering
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• v.7 no.1
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• pp.27-39
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• 2001

The multi-projective model considers attributes and the relationships among attributes called projections. The critical features of the multi-projective model are the way of relating attributes in the description of the system, the way of reasoning incomplete projections, and the determination of connected patterns between projection. In order to get a full picture of the system, we build a set of projections. The multi-projective model can be thought of as projections of a multi-dimensional reality onto simplified “model space”. The multi-projective database modeling approach used in this paper unified the ideas and terminology of various database models. Most importantly, the multi-projective modeling is presented as a tool of database design in the relational and other database models.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.838-840
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• 1999

In this paper, modeling and analysis of discrete event systems by temporal logic frame works and petri net is considered. The reachability tree of the petri net can be used to solve the safeness, boundedness, conservation and coverability problems of discrete event systems. But the reachability tree of the petri net do not solve reachability and liveness problems in general. We proposed a method that synthesised the petri net and the temporal logic frameworks. This method slove some problems of petri net by logical representation of temporal logic frameworks.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1091-1097
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• 1991

A logical and systematic procedure to derive a mathematical model for magnetically levitation(maglev) systems with a combined lift and guidance is developed by using and graph. First, bond graph is constructed for the energy-feeding system with magnetic leakage flux. And, the overall maglev system in which lift and guidance dynamics are coupled is modeled by using the concept of multi-port field in bond notations. Finally, the LQG/LTR control systems are designed for single-input single-output and for multi-input multi-output maglev systems. In this paper, it has been shown that the bond graph is an excellent method for modeling multi-energy domain systems such as maglev systems and the multivariable control system is required to improve the performance of the maglev system with a combined lift and guidance.

• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.359-372
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• 2000

Current CAD systems are good enough to be used as a tool to manipulate three-dimensional shapes. This is a very important capability to be owned by a design tool because a major portion of designers'activities is spent on the shape manipulation in the design detailing process. However, the whole design process involves a lot more than the, shape manipulation. Currently, these remaining tasks, mostly logical reasoning process for the function realization together with structure decomposition in the top-down manner, are processed in the designer's brain. To support the top-down functional design process of a mechanical product, a system integrating the functional, structural and geometrical aspects of a product design in a unified environment is presented. Using this system, a designer can perform function decomposition, structure decomposition, and geometry detailing, and function verification activities in parallel and the whole design process it modeled resultantly. Once the whole design process is modeled, any redesign task can be automatically performed with the verification of the desired functions.

• IE interfaces
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• v.14 no.2
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• pp.127-133
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• 2001

Virtual Manufacturing is a technology facilitating effective development and agile production of products via computer models representing physical and logical schema and the behavior of the real manufacturing systems. For the successful application of this technology, a virtual plant as a well-designed and integrated environment is essential. We propose a series of systematic approaches and effective methods for construction and operation of a virtual plant in this paper, such as a 3-D CAD modeling, cell and line simulations and databases. We developed key technologies for measuring and 3-D CAD modeling of many equipments, facilities and structures of the buildings. In order to study the benefit of virtual manufacturing, we constructed a sophisticated virtual plant model of a Korean automotive company's body shop, and conducted precise simulations of unit cell, lines and the whole plant. We could obtain the benefit of savings in time and cost in many manufacturing preparation activities in the new car development processes.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.144-155
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• 2003

In this paper, a conceptual data model, called the UDM(Unified Data Model), to efficiently represent database structures related with object technology and complex structured data, is proposed. This model integrates major features of modern data models, such as E-R model, Semantic Object Model, and UML, especially from the viewpoint of database design. This model is basically a simplified, but extended version of the Object-Relationship Model, which was proposed to model complex structures of temporal-spatial multimedia data. This model incorporates some of the important semantic and structural information of modern database applications and it is designed to support all of the major logical database models, including relational, object-relational, object-oriented, and (semi-)structured databases. A special diagrammatic technique, called the UDD(Unified Data Diagram), is introduced as a tool for database design. Also, possible ways to derive logical views of data from this unified data model are presented. The proposed model can be utilized as a convenient and practical tool for conceptual database designs.