• 정보기술과데이타베이스저널
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• 제6권2호
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• pp.45-57
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• 1999

This paper makes an attempt to find a systematic portion of the database design process, especially using the Entity-Relationship(E-R) model. Basically, we consider three aspects as a systematic portion of the database design process. They are, the strategy that a designer selects to design an E-R diagram, designer's cognitive style, and the knowledge and preference of the database designer. An experiment has been carried out in order to verify the systematic relationship between above-mentioned three aspects and the E-R modeling performance. The target system is a professional baseball system. A normative E-R diagram was constructed based upon 48 E-R diagrams produced during the experiment. The ANOVA process has been used to analyze the results. It has been found that there exist significant differences in query-answering capacity and the completeness of the E-R model among design methods. Individual differences in cognitive styles has not been found to be significantly related to the modeling performance.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1987년도 추계학술발표회 발표논문초록집; 중소기업협동조합중앙회, 서울; 31 Oct. 1987
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• pp.1-1
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• 1987

• 한국시뮬레이션학회논문지
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• 제11권2호
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• pp.55-66
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• 2002

VHDL has been. widely used in modeling and simulation of hardware designs. However, complex relationship between components of the designs makes the VHDL modeling problem very difficult. Furthermore, after the initial creation of VHDL models, they evolve into many versions over their lifetime. To cope with such difficulties, this paper proposes a new methodology for the management of VHDL models supporting versions. Its conceptual bases are system entity structure and relational database. Within the methodology, a family of hierarchical structures of a design is organized in the form of VHDL model structure. It is, in turn, represented in the form of relational tables. Once the model structure is built in such a way, a specific simulation model which meets design objective is pruned from the model structure. The details of VHDL codes are systematically synthesized by combining it with the primitive models in a model base. These algorithms are also defined in terms of relational algebraic operations.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.235-247
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• 2014

Based on two dimensional model partition method proposed in Part 1, Part 2 provides detailed model specification and implementation. To mathematically delineate a model's behaviors and interactions among them, we extend the DEVS (Discrete Event Systems Specification) formalism and newly propose CE-DEVS (Combat Entity-DEVS) for an upper abstraction sub-model of a combat entity model. The proposed CE-DEVS additionally define two sets and one function to reflect essential semantics for the model's behaviors explicitly. These definitions enable us to understand and represent the model's behaviors easily since they eliminate differences of meaning between real-world expressions and model specifications. For model implementation, upper abstraction sub-models are implemented with DEVSim++, while the lower sub-models are realized using the C++ language. With the use of overall modeling techniques proposed in Part 1 and 2, we can conduct constructive simulation and assess factors about combat logics as well as battle field functions of the next-generation combat entity, minimizing additional modeling efforts. From the anti-torpedo warfare experiment, we can gain interesting experimental results regarding engagement situations employing developing weapons and their tactics. Finally, we expect that this work will serve an immediate application for various engagement warfare.

• 한국기계가공학회지
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• 제18권8호
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• pp.91-97
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• 2019

A method for generating 3D solid models and drawings for a rotor in the steam turbine is proposed. One of the most important design steps is generating the drawing for manufacturing it. This step is a very routine and time-consuming job because each drawing is composed of several kinds of views and many dimensions. To achieve automation for this activity, rotor profiles are composed of 2D entity groups with attributes. Based on this, the improved design process is developed as follows. First, the rotor profiles can be selected by searching for 2D entity groups using the related attributes. Second, the profiles are connected sequentially so that an entire rotor profile is determined. The completed profile is used to generate 2D drawings automatically, especially views, dimensions, and 3D models. The proposed method is implemented using a commercial CAD/CAM system, Unigraphics, and API functions written in C-language and applied to the rotor of steam turbines. Some illustrative examples are provided to show the effectiveness of the proposed method.

• 한국정보시스템학회지:정보시스템연구
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• 제18권4호
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• pp.59-86
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• 2009

Data modeling can be regarded as a series of processes to abstract real-world business concerns. The conceptual modeling phase is often regarded as the most difficult stage in the entire modeling process, because quite different conceptual models may be produced even for similar business domains based on users' varying requirements and the data modelers' diverse perceptions of the requirements. This implies that an object considered as an entity in one domain may be considered as an attribute in another, and vice versa. However, many traditional knowledge-based automated database design systems unfortunately fail to construct appropriate Entity-Relationship Diagrams(ERDs) for a given set of requirements due to the rigid assumption that an object should be classified as an entity if it has been classified as an entity in previous applications. In this paper, we propose an alternative automation system which can generate ERDs from business descriptions using association rule mining technique. Our system can be differentiated from the traditional ones in that our system can perform data modeling only based on business description written by domain workers, rather than relying on any kind of knowledge base. Since the proposed system can produce various versions of ERDs from the same business descriptions simultaneously, users can have the opportunity to choose one of the ERDs as being the most appropriate, based on their business environment and requirements. We performed a case study for personnel management in a university to evaluate the practicability of the proposed system This paper summarizes the result of it in the experiment section.

• 한국CDE학회논문집
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• 제11권6호
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• pp.447-454
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• 2006

Although there are many needs to use 3D models in MEMS field, it is not easy to generate 3D models based on MEMS CAD. This is because MEMS CAD is based on 2D and their popular format-GDSII file format- has its own limits and problems. The differences between GDSII file format and 3D CAD system, such as (1) superposed modeling, (2) duplicated entity, (3) restricted of entity type, give rise to several problems in data exchange. These limits and problems in GDSII file format have prevented 3D CAD system from generating 3D models from the MEMS CAD. To remove these limits and solve problems, it is important to extract the silhouette of data in the MEMS CAD. The proposed method has two main processes to extract silhouette; one is to extract the pseudo-silhouette from the original 2D MEMS data and the other is to remove useless objects to complete the silhouette. The paper reports on the experience gained in data exchange between 2D MEMS data and 3D models by the proposed method and a case study is presented, which employs the proposed method using MEMS CAD IntelliMask and Solidworks.

• Journal of Information Technology Applications and Management
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• 제17권3호
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• pp.1-24
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• 2010

Most of enterprises depend on a data modeler during developing their management information systems. In formulating business requirements for information systems, they widely and naturally use the interview method between a data modeler and a field worker. But, the discrepancy between both parties would certainly cause information loss and distortion that lead to let the systems not faithful to real business works. To improve or avoid modeler-dependant data modeling process, many automated data design CASE tools have been introduced. However, since most of traditional CASE tools just support drawing works for conceptual data design, a data modeler could not generate an ERD faithful to real business works and a user could not use them without any knowledge on database. Although some CASE tools supported conceptual data design, they still required too much preliminary database knowledge for a user. Against these traditional CASE tools, we proposed a Requirement-Oriented Entity Relationship Model for automated data design tool, called ROERM. Based on Non-Stop Methodology, ROERM adopts inner systematic modules for complete and sound ERD that is faithful to real field works, where modules are composed of interaction modules with a user, rules of schema operations and sentence translations. In addition to structure design of ROERM, we also devise detailed algorithms and perform an experiment for a case study.

• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.89-99
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• 1999

The major objective of this research is to propose a design architecture for autonomous defense systems for supporting highly intelligent behavior by combining decision, perception, and action components. Systems with such high levels of autonomy are critical for advanced battlefield missions. By integrating a plenty of advanced modeling concepts such as system entity structure, endomorphic modeling, engine-based modeling, and hierarchical encapsulation & abstraction principle, we have proposed four layered design methodology for autonomous defense systems that can support an intelligent behavior under the complicated and unstable warfare. Proposed methodology has been successfully applied to a design of autonomous tank systems capable of supporting the autonomous planning, sensing, control, and diagnosis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.126-132
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• 2004

The database design for the management of bridge measurement information is presented in this paper. To express the associated data generated during the whole process of ambient measurement efficiently, requirements analysis for database construction is performed. And to define objects and organize schema conceptual and logical design are performed, which convert data model into logical schema. Finally, physical design is performed using DDL(data defined language). This database is based on the object-relational data modeling approach that has rich expressive power and good reusability in comparison with the traditional entity-relational modeling.