• Journal of KIISE
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• v.42 no.3
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• pp.390-398
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• 2015

Spatial web objects refer to web documents that contain geographic information. Recently, services that create spatial web objects have increased greatly because of the advancements in devices such as smartphones. For services such as Twitter or Facebook, simple texts posted by users is stored along with information about the post's location. To search for such spatial web objects, a method that uses spatial information and text information simultaneously is required. Conventional spatial web object search methods mostly use R-tree and inverted file methods. However, these methods have a disadvantage of requiring a large volume of space when building indices. Furthermore, such methods are efficient for searching with many keywords but are inefficient for searching with a few keywords.. In this paper, we propose a spatial web object search method that uses a quad-tree and a patricia-trie. We show that the proposed technique is more effective than existing ones in searching with a small number of keywords. Furthermore, we show through an experiment that the space required by the proposed technique is much smaller than that required by existing ones.

• Journal of Korea Multimedia Society
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• v.10 no.5
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• pp.652-667
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• 2007

With the wide spread of XML data in various fields, the interest in developing convenient user interfaces for inputting XML data is increasing. Previous works on the automated generation of user interfaces have given insufficient supports for various user environments and inconvenient editing tools for complex documents. In this paper, we presents an approach to generate XForms based user interfaces from XML schemas, for inputting XML data. The proposed method consists of three steps: parsing XML schemas, generating XForms codes, and embedding it into host language documents. Specifically, to generate XFonns codes, the rules for generating XForms codes, which support complex types and map simple types to appropriate input controls, are proposed. Experimental results with various kind of schemas show that the proposed method can generate XForms interfaces successfully.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.667-669
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• 2004

본 논문에서는 가상환경 국제 표준인 SEDRIS 기반의 가상현실 브라우저 개발에 대해 기술한다. 이 가상현실 브라우저는 가상환경을 구성하는 모든 객체들의 정보를 포함하고 있는 데이터의 구조를 가시화 하는 트리 뷰와 객체들의 3차원 모습을 표현하고 대화형 인터페이스에서 제어할 수 있는 렌더링 뷰로 구성되어 있다. 이 브라우저는 기존의 3차원 브라우저에서 다루어 온 가상세계의 가시화 실현의 의미 외에도 실세계를 구성하는 모든 객체들의 속성을 척도의 단위까지 묘사할 수 있는 국제적으로 표준화된 속성 기술 방법을 근거로 한다는 점에서 장점을 가진다.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.695-701
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• 1988

본 연구에서는 구조적 표현의 화상 처리 알고리즘인 BF(Breadth First) 선형 4진 트리 알고리즘(BFQT 알고리즘)의 압축, 재생부를 하드웨어화 하여 ASIC(Application Specific Integrated Circuit)을 설계한다. ASIC과 IBM PC와의 인터페이스를 명시하며, 새로운 하드웨어 알고리즘을 도입하여 ASIC의 세부구조를 설계한다. 소프트웨어로 수행할 때 보다 제안된 ASIC으로 수행할 때가 압축은 약 21배, 재생은 약 4배 빨라지는 것으로 추정된다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.579-582
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• 2004

본 논문에서는 PDA 장치를 위한 MPEG-4 콘텐츠를 저작하기 위한 스케일링 방법을 제안한다. 제안하는 스케일링 방법은 저작시 MPEC-4 콘텐츠의 씬 트리를 이용하여 PDA 장치에서 재생할 수 있도록 mp4 파일를 재구성하는 방법이다. 이 방법은 PDA 장치의 작은 인터페이스에서 재생을 효율적으로 할 수 있도륵 객체의 크기를 축소하고, 모든 객체를 아이콘의 기하 객체로 기술하여 초기 로딩 시간을 감소시킨다.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.80-85
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• 2021

In this study, for conducting a static load test of an external fuel tank used for an aircraft, the flight load acting on the external fuel tank was converted to the test load and the suitability of the converted test loads was confirmed. In order to calculate the test load from the flight load, the external fuel tank was divided into several sections. Shear load, moment by unit shear load, and unit moment were calculated for each section. Test loads for each section were then calculated by computing the shear load, the moment of each section, and flight load condition. In actual static load tests, it might not be possible to impose the test load in the calculated position due to physical constraints. Therefore, after determining positions in which the load could be imposed in the actual test, the test load calculated for each section was redistributed to selected positions. Finally, a test load plan was established by applying a whiffle tree to enhance the efficiency of the test performance while making it easier to operate the actuator. The reliability of the test load plan was verified by comparing it with flight load conditions.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.171-178
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• 2007

In mobile ad hoc networks, an application scenario requires mostly group mobility behavior in the mix of group moving nodes and individually moving nodes. The nodes of those applications tend to belong to the movement group with similar movement behavior. Group mobility is one of the good methods to improve scalability, and reduces the protocol overhead. In this paper, we propose the multicast architecture which regards nodes that have equal group mobility in the heterogeneous group mobility network as the single entity with the multiple interfaces and composes multicast tree, The logical cooperative entity-based multicast architecture accommodates the scalability, the multicast tree simplification, and the protocol overhead reduction which arc obtained from the hierarchical multicast architecture, while it maintains the nat multicast architecture for the data transmission. It also prevents the concentration of the energy consumption dispersing data forwarding load into the several ingress/egress nodes. Results obtained through simulations show that logical cooperative entity based multicast protocol with multiple interfaces offers the protocol scalability and the efficient data transmission.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.11-22
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• 2004

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per you. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules： the interface manager provides the interface for PDA users； the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques； the query manager processes spatial and non-spatial query : the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index : the GIS server interface provides the interface with disk-based GIS. The MR-tree proposed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimensional MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memory techniques, the memory data manager uses page tables for spatial data, non- spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.360-370
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• 2004

Adaptive mesh refinement(AMR) is one of the popular computational simulation techniques used in various scientific and engineering fields. Although AMR data is organized in a hierarchical multi-resolution data structure, traditional volume visualization algorithms such as ray-casting and splatting cannot handle the form without converting it to a sophisticated data structure. In this paper, we present a hierarchical multi-resolution splatting technique using k-d trees and octrees for AMR data that is suitable for implementation on the latest consumer PC graphics hardware. We describe a graphical user interface to set transfer function and viewing / rendering parameters interactively. Experimental results obtained on a general purpose PC equipped with an nVIDIA GeForce3 card are presented to demonstrate that the proposed techniques can interactively render AMR data(over 20 frames per second). Our scheme can easily be applied to parallel rendering of time-varying AMR data.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3559-3568
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• 1999

The information overload with many information resources is an inevitable problem in modern electronic life. It is more difficult to search some information with user's information needs from an uncontrolled flood of many digital information resources, such as the internet which has been rapidly increased. So, many information retrieval systems have been researched and appeared. In text retrieval systems, they have met with user's information needs. While, in image retrieval systems, they have not properly dealt with user's information needs. In this paper, for resolving this problem, we proposed the intelligent user interface for image retrieval. It is based on HCOS(Human-Computer Symmetry) model which is a layed interaction model between a human and computer. Its' methodology is employed to reduce user's information overhead and semantic gap between user and systems. It is implemented with machine learning algorithms, decision tree and backpropagation neural network, for user adaptation capabilities of intelligent image retrieval system(IIRS).