• Journal of KIISE:Databases
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• v.28 no.3
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• pp.344-356
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• 2001

This paper deals with the subsequence searching problem under time-warping in sequence databases. Our work is motivated by the observation that subsequence searches slow down quadratically as the average length of data sequences increases. To resolve this problem, the Segment-Based Approach for Subsequence Searches (SBSS) is proposed. The SBASS divides data and query sequences into a series of segments, and retrieves all data subsequences that satisfy the two conditions: (1) the number of segments is the same as the number of segments in a query sequence, and (2) the distance of every segment pair is less than or equal to a tolerance. Our segmentation scheme allows segments to have different lengths; thus we employ the time warping distance as a similarity measure for each segment pair. For efficient retrieval of similar subsequences, we extract feature vectors from all data segments exploiting their monotonically changing properties, and build a spatial index using feature vectors. Using this index, queries are processed with the four steps: (1) R-tree filtering, (2) feature filtering, (3) successor filtering, and (4) post-processing. The effectiveness of our approach is verified through extensive experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4170-4175
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• 2015

The global warming has been recognized as a serious problem. To solve this problem, the country of all the world have conducted techniques such as energy saving and reduction of greenhouse gas. The 30% of total energy is being consumed by buildings domestically and BAS/BEMS are being operated for the management of building energy. But, BEMS is unsatisfactory condition to manage the energy efficiently. In this study, We investigate real application on Chamsaem elementary school as a target buildings and develop 3D Web Browser platform. The spatial information of target buildings is described with used BIM and the energy information is presented for facilities operation and electricity consumption in floor and facility. We perform the quantitative evaluation based on ISO/IEC 9126 and operate this system for two months. in result, energy decreased by about 16%. We expect that the proposed 3D Web Browser system will bring operating efficiency improvement of the current BEMS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.273-282
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• 2002

Although the influence of GIS has been proved in a variety of applications, there also have been some research issues about that the coupling of GIS with other mathematical or engineering tools is necessary to meet various needs of specialized problem domains. Linear Programming, a mathematical technique used in optimal distribution of given quantity, can enhance its usability by integrating with GIS since LP basically does not include means to deal with spatial data. The limitation of the traditional LP technique is that it requires explicitly defined conditions, which is impractical or impossible in such decision making processes as in land use problems that use less crisp decision factors. This study develops a method to incorporate such fuzzy situations by integrating Fuzzy-LP that employs fuzzy logic and GIS. The GIS provides data to or displays data from the Fuzzy-LP processes in the integrated system. This methodology is illustrated to solve a land use distribution problem.

• Journal of Internet Computing and Services
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• v.20 no.3
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• pp.33-41
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• 2019

In this paper, we propose a method to learn the redesigned class with background and object for semantic segmentation of indoor scene image. Semantic image segmentation is a technique that divides meaningful parts of an image, such as walls and beds, into pixels. Previous work of semantic image segmentation has proposed methods of learning various object classes of images through neural networks, and it has been pointed out that there is insufficient accuracy compared to long learning time. However, in the problem of separating objects and backgrounds, there is no need to learn various object classes. So we concentrate on separating objects and backgrounds, and propose method to learn after class simplification. The accuracy of the proposed learning method is about 5 ~ 12% higher than the existing methods. In addition, the learning time is reduced by about 14 ~ 60 minutes when the class is configured differently In the same environment, and it shows that it is possible to efficiently learn about the problem of separating the object and the background.

• Structural Engineering and Mechanics
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• v.70 no.5
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• pp.551-562
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• 2019

In the present study, a suitable mathematical model considering parabolic transverse shear strains for dynamic analysis of laminated composite skew plates under different types of impulse and spatial loads was presented for the first time. The proposed mathematical model satisfies zero transverse shear strain at the top and bottom of the plate. On the basis of the cubic variation of thickness coordinate in in-plane displacement fields of the present mathematical model, a 2D finite element (FE) model was developed including skew transformations in the mathematical model. No shear correction factor is required in the present formulation and damping effect was also incorporated. This is the first FE implementation considering a cubic variation of thickness coordinate in in-plane displacement fields including skew transformations to solve the forced vibration problem of composite skew plates. The effect of transverse shear and rotary inertia was incorporated in the present model. The Newmark-${\beta}$ scheme was adapted to perform time integration from step to step. The $C^0$ FE formulation was implemented to overcome the problem of $C^1$ continuity associated with the cubic variation of thickness coordinate in in-plane displacement fields. The numerical studies showed that the present 2D FE model predicts the result close to the analytical results. Many new results varying different parameter such as skew angles, boundary conditions, etc. were presented.

• Journal of Broadcast Engineering
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• v.27 no.2
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• pp.198-206
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• 2022

This paper proposes a method to solve problems that may occur when SPIHT(set partition in hierarchical trees) is used in a dedicated codec for compressing complex holograms with ultra-high resolution. The development of codecs for complex holograms can be largely divided into a method of creating dedicated compression methods and a method of using anchor codecs such as HEVC and JPEG2000 and adding post-processing techniques. In the case of creating a dedicated compression method, a separate conversion tool is required to analyze the spatial characteristics of complex holograms. Zero-tree-based algorithms in subband units such as EZW and SPIHT have a problem that when coding for high-resolution images, intact subband information is not properly transmitted during bitstream control. This paper proposes a method of dividing wavelet subbands to solve such a problem. By compressing each divided subbands, information throughout the subbands is kept uniform. The proposed method showed better restoration results than PSNR compared to the existing method.

• Journal of the Korean GEO-environmental Society
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• v.23 no.7
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• pp.5-10
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• 2022

The industrial waste is becoming a big problem in the aspect of spatial and environmental in domestic and international. Therefore, the waste reduction and recycling policy has been being implemented as a way to solve this problem. The engineered stone sludge, which is waste, is generated duing the engineered stone production process. since engineered stone sludge is mostly treated by landfill, an increase in the amount of the sludge leads to an increase in landfill sites and treatment costs. therefore, there is a need for a method of resourcization with engineered stone sludge. So, laboratory tests (Plastic and liquid limits, compaction, unconfined compression and permeability test) were conducted to confirm the possibility of using engineered stone sludge mixed with weathered granite soil as a cover material for landfill in this study. The result shows that the mixed soil material with less that 62.5% of engineered stone sludge can be used as a cover material for landfill.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.217-227
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• 2022

In order to provide a location-based services regardless of indoor or outdoor space, it is important to provide position information of the terminal regardless of location. Among the wireless/mobile communication resources used for this purpose, Long Term Evolution (LTE) signal is a representative infrastructure that can overcome spatial limitations, but the positioning method based on the location of the base station has a disadvantage in that the accuracy is low. Therefore, a fingerprinting technique, which is a pattern recognition technology, has been widely used. The simplest yet widely applied algorithm among Fingerprint positioning technologies is k-Nearest Neighbors (kNN). However, in the kNN algorithm, it is difficult to find the optimal K value with the lowest positioning error for each location to be estimated, so it is generally fixed to an appropriate K value and used. Since the optimal K value cannot be applied to each estimated location, therefore, there is a problem in that the accuracy of the overall estimated location information is lowered. Considering this problem, this paper proposes a technique for adaptively varying the K value by using a Convolutional Neural Network (CNN) model among Artificial Neural Network (ANN) techniques. First, by using the signal information of the measured values obtained in the service area, an image is created according to the Physical Cell Identity (PCI) and Band combination, and an answer label for supervised learning is created. Then, the structure of the CNN is modeled to classify K values through the image information of the measurements. The performance of the proposed technique is verified based on actual data measured in the testbed. As a result, it can be seen that the proposed technique improves the positioning performance compared to using a fixed K value.

• Korean Institute of Interior Design Journal
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• no.21
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• pp.3-9
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• 1999

Contemporary society that is apt to be homogeneity because of the development of computer communication and mass-media desires to seek its own identity in native realm. Contemporary Korean architecture has endeavored continuous discussion and practice to keep its identity within the current tendency. The purpose of this study is to grope the alternative for genuine 'Koreaness' to analyse the variant trend of its characteristics 1990's. The variation of Korean society in 1990's that emphasize self-regulation and individual value has influence on the realm of architecture so much. The cognition of 'Koreaness' has changed with center in the individual and small -size design group, not present accommodation of past, but continuous research to find archetype of tradition which can play a decisive role of linking present and future on the foundation of past. Many attempts and practical works that express 'Koreaness' in 1990's are performed in the area of residence works that reflect Korean emotion and life-style directly. This change can be an answer to solve the problem of peculiarity and universality in 'Koreaness'. After 1960's the main theme of 'Koreaness' was traditional architecture form, but because of the induction of Postmodernism and at once its reflection and critical attitude with limit of formal duplication, which lost its meaning. In 1990's, research for spatial form as korean emotion and image has carried out and played an important part of original expression for 'Koreaness'

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.41-50
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• 1998

The detemination of sound pressure radiated from peoriodic plate structures is fundamental in the estimation of noise levels in aircraft fuselages and ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model for predicting the sound radiated by a vibrating plate stiffened by periodically spaced orthogonal symmetric beams subjected to a sinusoidally time varying point load is developed. The plate is assumed to be infinite in extent, and the beams are considered to exert both line force and moment reactions on it. Structural damping is included in both plate and beam materials. A space harmonic series representation of the spatial variables is used in conjunction with the Fourier transform to find the sound pressure in terms of harmonic coefficients. From this theoretical model. the sound pressure levels on axis in a semi-infinite fluid (water) bounded by the plate with the variation in the locations of an external time harmonic point force on the plate can be calculated efficiently using three numerical tools such as the Gauss-Jordan method, the LU decomposition method and the IMSL numerical package.