• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.184-187
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• 2002

Two-dimensional (2-D) X-ray computerized tomography (CT) equipments are widely used in industrial and medical fields, and nowadays studies on reconstruction algorithm for 3-D cone-beam acquisition systems are active for better utilization. The authors recent-By have proposed a fast reconstruction aigorithm using tree-structured filter bank for 2-D C1, and shown the algorithm is applicable to an approximate reconstruction of 3-D CT. For exact 3-D CT reconstruction, however, we have to backproject 1-D signal into 3-D space. This paper proposes a fast implementation method for this back-projection by use of tree-structured filter bank. and shows the proposed method works approximately 700 times faster than the direct one with almost same reconstruction image quality.

• Spatial Information Research
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• v.18 no.2
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• pp.57-65
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• 2010

Users often visit many stores while comparing the products for purchasing products or products related to it. Given a service providing location information of these stores, users can make their purchase efficiently because of reducing the time and effort they spent for wandering around and obtaining new purchase opportunities by knowing a kind of relevant stores near there. In this paper, for the purpose of providing relevant stores information efficiently, we suggest an Ambient Service Model that consists of three layers: "structured(purchase-related) information space", "real space", and "ambient information space". In the model, stores information collected from the web is grouped and structured automatically by relationships in terms of purchase. And users search relevant stores information by using an Ambient Query that is created by their context in real space. Finally, users obtain relevant stores information that is in the form of hierarchy structure on map interface. Then, users can search other kinds of relevant stores information additionally by using hierarchy structure. Consequently, It is possible to develope a service that users can obtain relevant stores information intuitively without complex search processes through the model. Also, we expect that the model can be used for developing services that provide objects information related to various objects besides stores.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.140-152
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• 2003

An XML document has a structure which may be irregular. It is difficult for end-users to comprehend the irregular document structure exactly. For these XML documents, an end-user has a difficulty in using structured query. Therefore, an end-user formulates no structured query or a query which has a little structure information. In this context, we propose new retrieval models which use the structured information for ranking and compensate the difference between user query structure and document structure. To ease with querying, we assume the independence among querying paths which represent structural constraints. Since this assumption makes degradation of the expression power of a query language, we also propose a model which overcome this problem. As there had been no test collections for XML documents, we made a small test collection from TIPSTER of the RTEC and experimented on this collection without a structured query, From this experiment, we showed that our models improve average precision about 67% over conventional Vector-Space model.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.737-740
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• 2009

3D VR modeling data can be used for powerful expression in construction, because it gives help to navigate a construction in 3D space easily. But the current status of VR technique visualizes only an external shape of a construction. A construction has not only its external shape data but also its constructive information. The constructive information is very important and can be expressed as the process of construction and deconstruction. Thus we research on recording and replay interface to manipulate 3D structured objects for the process of construction and deconstruction.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.274-281
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• 1999

Many popularly used recent high-sped and high-capacity disks use the Zone-Structured in which a disk consists of multiple zones. A zone-structured disk has multiple zones, and the bandwidth and the number of sectors in each zone are different from each other. When the previous studies that modeled disks based on the assumption that the number of sectors in all tracks are same are applied to the zone-structured disk and the video data stored in a round-robin manner are read out with the SCAN technique, the transfer rate of the disk is fixed with that of the innermost zone. And excessive disk space is wasted either. To resolve the problem, this paper proposes a method for reconstructing the physical zones into logical zones by split and merge operations and develops a method for determining optimum transfer block size.

• Korean Journal of Remote Sensing
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• v.3 no.2
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• pp.115-119
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• 1987

After the introduction of the topologically structured geographic information system(GIS) with relational DBMS, the attribute data can be handled without considering locational data. By utilzing of the characteristic of the relational DBMS, it can be used as an expert system building tool in GIS. The relational DBMS of the GIS furnishes the data needed to perform deductive functions of the expert system, and the rule based approach provides the decision rules. Therefore, rule based approach with the expert judgement can be easily combined with relational DBMS.

• Spatial Information Research
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• v.22 no.6
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• pp.13-21
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• 2014

This study defines concept and service framework of Geo-Spatial Big Data(GSBD). The major concept of the GSBD is formulated based on the 7V characteristics: the general characteristics of big data with 3V(Volume, Variety, Velocity); Geo-spatial oriented characteristics with 4V(Veracity, Visualization, Versatile, Value). GSBD is the technology to extract meaningful information from Geo-spatial fusion data and support decision making responding with rapidly changing activities by analysing with almost realtime solutions while efficiently collecting, storing and managing structured, semi-structured or unstructured big data. The application area of the GSBD is segmented in terms of technical aspect(store, manage, analyze and service) and public/private area. The service framework for the GSBD composed of modules to manage, contain and monitor GSBD services is suggested. Such additional studies as building specific application service models and formulating service delivery strategies for the GSBD are required based on the services framework.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.11
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• pp.93-101
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• 1993

The transfer function of vector-controlled induction motor is represented along with both unstructured and structured uncertainty such as the error of rotor time constant and current ripple. The low-pass-filter behavior of a magnetizing inductance gets rid of unstructured uncertainty in the transfer function. The robust controller to compensate variation of the transfer function is designed using simple P-I linear controllers. The coefficients of speed PI controller are determined from an overshoot and a rising time of system and the coefficients of model-following PI controller are obtained using the solution of Riccati equation of LQR control in the state space equation of the error system. Experimental results with the DSP-based model-following robust controller are shown a good robustness against the structured uncertainty of the motor.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.61-66
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• 2007

The networked home is connected to the external world using a high speed network. The devices inside the house are connected using a wired and wireless network. Acquiring the user data is an essential step for designing the user interface in user centered design. In networked home, the numbers of use cases are exponentially increased because connected use cases are considered. Because the user data for networked home are too complicated, they are acquired and analyzed by a structured methodology. We surveyed 40 people to acquire the context data home and analyzed by 5W1H (Who, Where, What, When, Why, How). We established a framework for the user data using tasks, user, time, space, objects and environment. The data for home context was structured by our framework. This framework makes simple the home context and is helpful for user interface design in home network.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.109-117
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• 2020

A structured grid system can be efficiently constructed by applying the patched-grid algorithm that alleviates many constraints of the conventional structured grid system. Three approaches were applied to case 4 of the EFD-CFD workshop: delta wing-cylindrical body shape to solve the existing grid generation problems and verify the results by comparing them with experimental data. Surface pressure distributions slightly differed from the experimental data at high angles of attack. The slope variation of the pitching moment with Mach number is analyzed and the variation can be explained with the tuck under phenomenon. In the supersonic region, the bow shock waves in front of the shape expand the region generating lift up to the rear of the configuration. Also, the tendency of the pitching moment with both Mach number and angle of attack was analyzed by comparing the positions of the center of pressure and the center of gravity.