• Journal of KIISE:Databases
• /
• v.31 no.2
• /
• pp.150-162
• /
• 2004

Moving objects have characteristics that they change continuously their positions over time. The movement of moving objects should be stored on trajectories for processing past queries. Moving objects databases need to provide spatio-temporal index for handling moving objects queries like combined queries. Combined queries consist of a range query selecting trajectories within a specific range and a trajectory query extracting to parts of the whole trajectory. Access methods showing good performance in range queries have a shortcoming that the cost of processing trajectory Queries is high. On the other hand, trajectory-based index schemes like the TB-tree are not suitable for range queries because of high overlaps between index nodes. This paper proposes new TR(Trajectory Riving)-tree which is revised for efficiently processing the combined queries. This index scheme has several features like the trajectory preservation, the increase of the capacity of leaf nodes, and the logical trajectory riving in order to reduce dead space and high overlap between bounding boxes of nodes. In our Performance study, the number of node access for combined queries in TR-tree is about 25% less than the STR-tree and the TB-tree.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.758-765
• /
• 2016

This paper is a follow-up paper to the publication, "Development of Tunnel-Environment Monitoring System and Its Installation I - Monitoring System and Measurement in Subway Tunnel" [1]. An environment monitoring system was installed in the 20.3-km-long Gumjung tunnel, which has the general structure of a high-speed double-track railway tunnel. Data were collected for approximately one year. Monthly and daily data were obtained and analyzed for the temperature and relative humidity in summer and winter months. This paper discusses the environmental characteristics at different positions in the tunnel. The results are expected to be widely used in studies on tunnel ventilation and the improvement of air quality and thermal environments.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.1947-1953
• /
• 2012

The vehicle fuel economy is very important issue in the view of global warming. This paper proposes the three fuel economy improvement algorithms which predict the velocity using altitude data of the positions in front of vehicle and estimates their performances. The proposed 3 algorithms are WMGA(Weighted Mean Gradient Angle), RAADE I, II(Reacceleration After Deacceleration I, II). This research extracts the distance and altitude data from received GPS data and calculates gradient angle and road load for each section. The velocity profile according to proposed algorithms is made for Youngdong highway of 213km. And the test vehicle runs along this highway and fuel economy is measured. RAADE II of proposed algorithms showed better performance by 3.571% in comparison to the conventional CVELCONT3.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3280-3286
• /
• 2009

In this paper, we designed and manufactured HD Switch Panel parts with micro-etched pattern. By using CAE analysis, we could predict weld-line positions and the amount of shrinkage during injection molding process. We measured the temperature distribution of the mold surface so that we could optimize the processing conditions such as mold temperature. In order to increase the transcription of micro-etched pattern, we applied the E-Mold technology and evaluated the effect of mold temperature on the surface quality. We concluded that the etched pattern was improved(more than 2.5$\to$1.5~1.7) through the measurement of surface gloss and the observation of both SEM and SPM images.

• Journal of the Institute of Convergence Signal Processing
• /
• v.1 no.1
• /
• pp.58-63
• /
• 2000

This paper describes an efficient algorithm for shot boundary detection in MPEG video stream. There are two types of shot boundary: abrupt and gradual. The proposed algorithm for detecting the abrupt shot boundaries used DCT DC value in compressed domain. The proposed algorithm of the gradual change detection consists of two-pass mechanism. In the first pass, the expected positions of shot boundaries are extracted using ratio value of motion vectors. After decoding frames that are extracted in the first pass, we will make the dissolving image using (n)th and (n+2)th image of expected position. The gradual shot boundaries are selected by similarity of the dissolving image and the image of (n+1)th expected position. As applying the algorithm for detecting shot boundaries, the gradual changes as well as the abrupt changes are detected efficiently. Experimental results indicate that the proposed method is computationally fast for detecting shot boundaries and robust to the variation of the video characteristic that is different for the kind of videos.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.5
• /
• pp.1-12
• /
• 2018

This study presents the seismic response characteristics of domestic cable-supported bridges due to 3 earthquakes with magnitudes of 5.1, 5.8, and 4.5 in Richter scale, which occurred around Gyeongju region in 2016. The seismic acceleration response signals, recorded by the seismic acceleration sensors at the free field near bridge and designated positions on bridge, are utilized to characterize the seismic responses of structural elements of cable-supported bridges. The dynamic behaviors of bridges are presented through Fourier transform of acceleration time history. Using the peak accelerations normalized by those at the free fields, amplification effects on the tops of the pylons are analyzed comparatively bridge by bridge. Using aforementioned analyses, the necessity of development on the creteria of alert levels is discussed for the earthquake disaster response of cable-supported bridges.

• Journal of the Institute of Convergence Signal Processing
• /
• v.11 no.3
• /
• pp.232-237
• /
• 2010

In this paper, a slit light laser range finding method using perspective warping calibration is proposed. This approach has an advantage to acquire relatively high accuracy, although the optical system is nonlinear. In the calibration, we detect the calibration points which are marked on the calibration panel and acquire the center position of the slit light laser in the image, which are used for computing the real positions of the slit light by using perspective warping. A calibration file is obtained by integrating the calibration data with the transition of the panel. The range data is acquired by interpolating the center position of the slit light laser to the calibration coordinates. Experimental results show that the proposed method provides the accuracy of 0.08mm error in depth range of 130mm with the low cost optical system.

• Restorative Dentistry and Endodontics
• /
• v.23 no.2
• /
• pp.575-585
• /
• 1998

Use of the digital camera as a color measuring device was proposed. Digital camera can save, adjust and transmit image using computer. But it has great disadvantage that color of image possibly altered by environment of image capturing state, so the color reproducibility of digital camera can severly damage, Casmatch, the supplement for color correction, was proposed for enhance the color reproducibility of digital camera. Thus for study the efficacy of the Casmatch in enhancing the color reproducibility of digital camera, image of 78area in 39teeth was captured three times during two days and color reproducibility was evaluated and analyzed in terms of the use of Casmatch, teeth positions, and area within the tooth and comparatively analyzed. Results were as follow ; 1. ${\Delta}$E the color reproducibility of digital camera was 6.90${\pm}$3.27 in same day and 7.43${\pm}$3.94 in different day, and the color reproducibility when using Casmatch correction was 6.21${\pm}$3.86, 7.59${\pm}$4.48, there is no enhancement in using Casmatch correction. 2. There is no difference in color reproducibility between teeth, but color reproducibility of the middle third was greater(p<0.05) than the gingival third before color correction using Casmatch.

• Journal of KIISE:Computing Practices and Letters
• /
• v.7 no.6
• /
• pp.724-732
• /
• 2001

In this paper, a new method of feature extraction of major objects to represent an image using Vector Quantization(VQ) is proposed. The principal features of the image, which are used in a content-based image retrieval system, are color, texture, shape and spatial positions of objects. The representative color and texture features are extracted from the given image using VQ(Vector Quantization) clustering algorithm with a general feature extraction method of color and texture. Since these are used for content-based image retrieval and searched by objects, it is possible to search and retrieve some desirable images regardless of the position, rotation and size of objects. The experimental results show that the representative feature extraction time is much reduced by using VQ, and the highest retrieval rate is given as the weighted values of color and texture are set to 0.5 and 0.5, respectively, and the proposed method provides up to 90% precision and recall rate for 'person'query images.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.6
• /
• pp.11-15
• /
• 2009

Recently, a new PSC (Prestressed Concrete) bridge system, which is supported by Concrete-filled fiber-reinforced polymer (CFFRP) strut, has been introduced. This bridge is able to reduce self-weight and increase the width of traditional PSC bridges. However, no relevant research has been reported on local behavior of CFFRP strut in the bridge system. The purpose of this study is to investigate local behavior of CFFRP struts using fiber Bragg grating (FBG) sensors. Field tests were performed to examine the hoop strains and longitudinal strains of the FRP strut under various lateral positions and velocities of a test truck. It has been observed that CFFRP strut is under compression regardless of vehicle speed and location. However, the CFFRP strut is sensitive to the lateral position of vehicles in terms of strain magnitude. Results also indicated that the FBG sensors can faithfully record the hoop and longitudinal strains of the FRP strut without electro-magnetic interference.