• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.2-28.2
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• 2008

Recently, star sensors have been successfully used as main attitude sensors for attitude control in many satellites. This research presents the star visibility analysis for star trackers and the goal of this analysis is to make sure that the star tracker implementation is suitable to the mission profile and scenario and satisfies the requirement of attitude orbit control system. As a main optical attitude sensor imaging stars, accomodations of a star tracker should be optimized in order to improve the probability of the usage by avoiding the blinding (the unavailability) by the Sun and the Earth. For the analysis, a statistical approach and a time simulation approach are used. The statistical approach is based on the generation of numerous cases, to derive relevant statistics about Earth and Sun proximity probabilites for different lines of sight. The time simulation approach is performed for one orbit to check the statistical result and to refine the statistical result and accomodations of star trackers. In order to perform simulations first of all, an orbit and specific mission profiles of a satellite are set, next the earth proximity probability and the sun proximity probability are calculated by considering the attitude maneuvers and the geometry of the orbit, and then finally the unavailability positions are estimated. As a result, the optimized accomodations of two star trackers are suggested for the low earth orbit satellite.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.470-482
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• 2007

In this paper, we classify next generation mobile communications services into service categories and develop service evolution scenarios for developing the next generation mobile communications service roadmap in NGMC Forum. Firstly, Service categories are defined based on the purpose of service usage. Secondly, the services are classified into the categories and their relationship is analyzed. The candidates of services to be classified and analyzed include all kinds of services discussed in a conceptual level as well as current mobile/Internet services. Finally, we develop a service evolution scenario in each service category. When the next generation service road map is developed based on the results of this paper, it is expected to secure the initiative and enhance the competitive edge in the field of the next generation mobile communications.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.217-224
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• 2003

ISO 14649 is a new interface (or language) standard for the CAD-CAM -CNC chain, currently under establishment by ISO TC184 SCI and SC4 . Upon completion, it will replace ISO 6983, so called M amp; G codes used for CNC since 1950' s. As the new language is being established, a new CNC controller called STEP-CNC (STEP­compliant CNC), capable of carrying out various intelligent tasks using the new language as an input, receives worldwide attention. In this paper, we present a distributed architecture for STEP-NC system based on the generic paradigm of STEP-NC. The STEP-NC system is consisted of 3 sub-systems: 1) CGS (Code Generation System), 2) CES (Code Edit System), and 3) ACS (Autonomous Control System). Also presented in this paper is algorithm for delta volume decomposition, a crucial algorithm for developing CGS. First method is based on the cutting tool and the second method is based on the turning features commonly used in the shop floor. An illustrative example is given to compare the two methods, and to illustrate usage scenario of the delta volume in the turning STEP- NC system under development.

• The Journal of Korean Association of Computer Education
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• v.10 no.3
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• pp.39-48
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• 2007

Due to the rapid proliferation of the web in recent years, many educators seek to improve the effectiveness of their instruction by providing innovative web-based course material to their students. Lots of web-based education contents are developed especially. They help to teach and train students. They expand widely due to repetition learning any time, any where. In this paper we implemented usage of C functions, quizes for checking comprehension of statements in C programming lecture and developed scenario helping concepts, algorithm comprehension. We made them web-based visual representation. They were implemented as FLASH animations or Java applets. They were well received by students.

• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.97-106
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• 2007

A core technology that may realize the Semantic Web is Ontology. The OWL (Web Ontology Language) has been positioned as a standard language. It requires technical expertise to directly represent the domain knowledge in OWL. Based on our experience of analyzing the fundamental relationships of concepts in e-catalog domain, we have developed a visual product information modeler called PROMOD. The modeling editor makes it possible to automatically generate the OWL codes for the given product information. We employ an Extended Entity-Relationship for conceptual modeling, enriched with modeling elements specialized for the product domain. In this paper, we present our translation schemes from EER model to OWL codes, and how to design and implement the modeling editor. We also provide a scenario to demonstrate the usage of the editor in practice.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.702-706
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• 2010

In this paper, we propose a framework to change local devices to networked devices by using web browser. Network devices will be used in the virtual desktop. Management software maintains a pool of devices to manage network devices. Whenever user's request is occured, virtual desktop s/w which manages desktop's I/O access device pool. Then virtual desktop s/w selects proper device and forwards I/O to desktop. In this paper, we choose RIA solution for install-free environment. Consequently, user easily enrolls and revokes their devices. User easily commands virtual desktop s/w. In the second half of this paper, we explain usage scenario and evaluate our framework to show efficiency and flexibility of the framework.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.2
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• pp.135-151
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• 2014

It is very important to properly understand such "Transport Pathways" elements as "Pipe" and "Cell" pathways in commercial GoldSim Transport Module (GTM) for developing higer quality models and programs for performance assessment of complex radioactive waste repositories. With an illustrative case under an earthquake scenario, by which an increasement in the groundwater flow rate occurs though the geological medium, ways of avoiding possible modeling errors in the nuclide transport modeling in the radioactive waste repository system for its safety assessment by utilizing such pathways are discussed and a proper usage of the pathways is proposed.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.15-23
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• 2013

Because that construction project is usually uncertain and the plan of it changes frequently, it is difficult to make a reliable and feasible plan for it. As the BIM technology is developed, we can simulate the future of the construction project visually and make more reliable plan. However, data production efficiency is not so high, it is used just for animation and presentation usage. Although, a lot of construction simulation systems are developed, it is difficult to measure performance of them. In this study, we defined the construction simulation work process and the scenarios to measure performance of them. The performance measurement method using simulation process scenario can make possible benchmark test of them.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.765-781
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• 2019

This study predicts the power consumption of an Electric Propulsion Ship (EPS) in marine environment. The EPS is driven by a propeller rotated by a propulsion motor, and the power consumption of the propeller changes by the marine environment. The propulsion motor consumes the highest percentage of the ships' total power. Therefore, it is necessary to predict the power consumption and determine the power generation capacity and the propeller capacity to design an efficient EPS. This study constructs a power estimation simulator for EPS by using a ship motion model including marine environment and an electric power consumption model. The usage factor that represents the relationship between power consumption and propulsion is applied to the simulator for power prediction. Four marine environment scenarios are set up and the power consumed by the propeller to maintain a constant ship speed according to the marine environment is predicted in each scenario.

• Korean Journal of Computational Design and Engineering
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• v.16 no.2
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• pp.137-145
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• 2011

A variety of BIM libraries are required to apply BIM(Building Information Modeling) software and generate BIM data. However, enterprises are establishing their own libraries using BIM tools, the drawbacks are that these libraries are not open to other users, or they just can be used in some software packages. If IFC(Industry Foundation Classes), the standard format of open BIM, can be applied, the BIM library can be applied in all the BIM software packages. Although the enterprises can collaborate using IFC standard, it is difficult to represent all the property information of the construction materials by IFC. IFD(International Framework for Dictionaries) is used to solve these problems and add the property information of the construction materials easily. Therefore, Open RIM-based library needs to be developed using IFD. In this research, the development and application of BIM library and IFD in domestic and foreign countries were investigated and analyzed, and Open BIM-based IFD scenario was proposed for using, and finally by applying an IFD method, the IFD data was added within an IFC model. Consequently, Open BIM-based library can be extended with rich, formal, and semantic descriptions and enhance data interoperability among BIM software packages adopting Open BIM standard format, by applying the IFD.