• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1016-1022
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• 2014

Kinect is a motion sensing camera released by Microsoft in November 2010 for the Xbox360 that is used to produce depth and color images. Because Kinect uses an infrared pattern, it generates holes and noises around an object's boundaries in the obtained images. The flickering phenomenon and unmatched edges also occur. In this paper, we propose a real time virtual-view video synthesis algorithm which results in a high quality virtual view by solving these problems stated above. The experimental results show that the proposed algorithm performs much better than the conventional algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.117-120
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• 2004

본 논문에서는 시계열 데이터베이스에서 타임 워핑 하의 서브시퀀스 매칭을 효과적으로 처리하는 방안에 관하여 논의한다. 타임 워핑은 데이터베이스내 시퀀스들의 길이가 서로 다른 경우에도 유사한 패턴을 갖는 시퀀스들을 찾을 수 있도록 해 준다. 본 논문에서는 타임 워핑 하의 서브시퀀스 매칭을 위한 기존의 기본 처리 방식인 Naive-Scan의 CPU 처리 과정을 최적화하는 새로운 기법을 제안한다. 제안된 기법은 질의 시퀀스와 서브시퀀스들 간의 타임 워핑 거리들을 계산하는 과정에서 발생하는 중복 작업들을 사전에 제거함으로써 CPU 처리 성능을 극대화한다. 제안된 기법이 착오 기각을 발생시키지 않음과 Naive-Scan을 처리하기 위한 최적의 기법임을 이론적으로 규명한다. 또한, 다양한 실험을 통한 성능 평가에 의하여 제안된 최적화 기법이 가져오는 성능 개선 효과를 정량적으로 검증한다. 아울러, 제안된 기법이 기존의 여과 단계를 포함하는 방식인 LB-Scan과 ST-Filter의 후처리 단계에도 성공적으로 적용될 수 있음을 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.37-40
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• 2024

본 연구에서는 웨어러블 디바이스로부터 수집된 다변량 반려동물 행동 데이터를 처리하기 위해, GCN(Graph Convolutional Network)과 GRU(Gated Recurrent Unit)를 결합한 모델을 제안한다. 제안된 모델은 시계열 내부 구조를 활용하여 그래프 구조로 변환하고, DTW(Dynamic Time Warping) 유사도 분석을 통해 노드 간의 시간적 유사도를 기반으로 엣지를 생성한다. 실험결과로 DTW 기반 엣지 생성 방식이 유클리드 거리 및 선형 방식에 비해 더 높은 성능을 나타냈다. 본 연구는 반려동물의 행동을 정확히 분류하기 위한 효과적인 방법론을 제공한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.535-543
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• 2019

Recently, growing social interest in alley markets, which have shown rapid growth like Gyeonglidan-gil street in Seoul, has led to the need for an analysis of growth factors. This paper aims at exploring growing alley markets through time-series clustering using DTW (Dynamic Time Warping) and examining the growth factors through logistic regression. According to cluster analysis, the number of growing markets of the Northeast, the Southwest, and the Southeast were much more than the Northwest but the proportion in region of the Northwest, the Northeast, and the Southwest were much more than the Southeast. Logistic regression results show that people in 20s and 30s have a lower impact on sales than those in 50s, but have a greater impact on growth of alley market. Alley markets located in high-income areas often reached their growth limits, indicating a tendency to stagnate or decline. The proximity of a subway station effected positive on sales but negative on growth. This research is an advanced study in that the causes of sales growth of alley markets is examined, which has not been examined in the preceding study.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.13-20
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• 2020

One of the major issues surrounding big data is the availability of massive time-based or telemetry data. Now, the appearance of low cost capture and storage devices has become possible to get very detailed time data to be used for further analysis. Thus, we can use these time data to get more knowledge about the underlying system or to predict future events with higher accuracy. In particular, it is very important to define custom tailored contract offers for many households and businesses having smart meter records and predict the future electricity usage to protect the electricity companies from power shortage or power surplus. It is required to identify a few groups with common electricity behavior to make it worth the creation of customized contract offers. This study suggests big data transformation as a side effect and clustering technique to understand the electricity usage pattern by using the open data related to smart meter and KNIME which is an open source platform for data analytics, providing a user-friendly graphical workbench for the entire analysis process. While the big data components are not open source, they are also available for a trial if required. After importing, cleaning and transforming the smart meter big data, it is possible to interpret each meter data in terms of electricity usage behavior through a dynamic time warping method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.35-44
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• 2012

Most recent infrared (IR) sensors have a focal-plane array (FPA) structure. Spatial non-uniformity of a FPA structure, however, introduces unwanted fixed pattern noise (FPN) to images. This non-uniformity correction (NUC) of a FPA can be categorized into target-based and scene-based approaches. In a target-based approach, FPN can be separated by using a uniform target such as a black body. Since the detector response randomly drifts along the time axis, however, several scene-based algorithms on the basis of a video sequence have been proposed. Among those algorithms, the state-of-the-art one based on Kalman filter uses one-directional warping for motion compensation and only compensates for offset non-uniformity of IR camera detectors. The system model using one-directional warping cannot correct the boundary region where a new scene is being introduced in the next video frame. Furthermore, offset-only correction approaches may not completely remove the FPN in images if it is considerably affected by gain non-uniformity. Therefore, for FPN reduction in IR videos, we propose a joint correction algorithm of gain and offset based on bi-directional warping. Experiment results using simulated and real IR videos show that the proposed scheme can provide better performance compared with the state-of-the art in FPN reduction.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.414-420
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• 2015

The quality of depth images is important in the 3D video system to represent complete 3D contents. However, the original depth image from a depth camera has a low resolution and a flickering problem which shows vibrating depth values in terms of temporal meaning. This problem causes an uncomfortable feeling when we look 3D contents. In order to solve a low resolution problem, we employ 3D warping and a depth weighted joint bilateral filter. A temporal mean filter can be applied to solve the flickering problem while we encounter a residual spectrum problem in the depth image. Thus, after classifying foreground andbackground regions, we use an upsampled depth image for a foreground region and temporal mean image for background region.Test results shows that the proposed method generates a time consistent depth video with a high resolution.

• Journal of Korea Game Society
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• v.10 no.1
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• pp.147-156
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• 2010

In this paper, we propose 3D cloud animation by cloud modeling method of 2D images retrieved from a meteorological satellite. First, on the satellite images, we locate numerous control points to perform thin-plate spline warping analysis between consecutive frames for the modeling of cloud motion. In addition, the spectrum channels of visible and infrared wavelengths are used to determine the amount and altitude of clouds for 3D cloud image reconstruction. Pre-integrated volume rendering method is used to achieve seamless inter-laminar shades in real-time using small number of slices of the volume data. The proposed method could successfully construct continuously moving 3D clouds from 2D satellite images at an acceptable speed and image quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1456-1461
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• 2003

Recently, the quantity of using information go on increasing geometric-progression. At the same time, the management of information is effected on the most organization's effective operation so that many user call for the powerful equipment which expound. access more information. As information searching technology is concentrated about the object of information based on a letter mainly, an effective searching technology for the object of multimedia such as a still image, a video and a sound must be studied. As a monitor of computer is 2-D, it difficult for one to grasp the whole aspect at a look glance like a library. Accordingly, some condition is necessary. First, it acquired the virtual video, turning a camera around by 30 degrees with a camera of 15mm lens, giving a warping and distortion. Second, it improved the books for user to search easily, adding to the video in existing books information system. The original text suggests some way which can embody the video searching technology under the base of personal computer.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.4
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• pp.63-73
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• 2023

This study explores modern portfolio theory by integrating the Black-Litterman portfolio with time-series clustering, specificially emphasizing K-shape clustering methodology. K-shape clustering enables grouping time-series data effectively, enhancing the ability to plan and manage investments in stock markets when combined with the Black-Litterman portfolio. Based on the patterns of stock markets, the objective is to understand the relationship between past market data and planning future investment strategies through backtesting. Additionally, by examining diverse learning and investment periods, it is identified optimal strategies to boost portfolio returns while efficiently managing associated risks. For comparative analysis, traditional Markowitz portfolio is also assessed in conjunction with clustering techniques utilizing K-Means and K-Means with Dynamic Time Warping. It is suggested that the combination of K-shape and the Black-Litterman model significantly enhances portfolio optimization in the stock market, providing valuable insights for making stable portfolio investment decisions. The achieved sharpe ratio of 0.722 indicates a significantly higher performance when compared to other benchmarks, underlining the effectiveness of the K-shape and Black-Litterman integration in portfolio optimization.