• Korean Journal of Remote Sensing
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• v.35 no.4
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• pp.573-587
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• 2019

A multi-temporal approach using remotely sensed time series data obtained over multiple years is a very useful method for monitoring land covers and land-cover changes. While spectral-based methods at any particular time limits the application utility due to instability of the quality of data obtained at that time, the approach based on the temporal profile can produce more accurate results since data is analyzed from a long-term perspective rather than on one point in time. In this study, a multi-temporal approach applying a multi-periodic harmonic model is proposed for classification of remotely sensed data. A harmonic model characterizes the seasonal variation of a time series by four parameters: average level, frequency, phase, and amplitude. The availability of high-quality data is very important for multi-temporal analysis.An satellite image usually have many unobserved data and bad-quality data due to the influence of observation environment and sensing system, which impede the analysis and might possibly produce inaccurate results. Harmonic analysis is also very useful for real-time data reconstruction. Multi-periodic harmonic model is applied to the reconstructed data to classify land covers and monitor land-cover change by tracking the temporal profiles. The proposed method is tested with the MODIS and GOCI NDVI time series over the Korean Peninsula for 5 years from 2012 to 2016. The results show that the multi-periodic harmonic model has a great potential for classification of land-cover types and monitoring of land-cover changes through characterizing annual temporal dynamics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5860-5876
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• 2018

A single snapshot data can only provide limited amount of information so that the rank of covariance matrix is not full, which is not adopted to complete the parameter estimation directly using the traditional super-resolution method. Aiming at solving the problem, a joint time delay and angle estimation using matrix pencil method based on information reconstruction vector for orthogonal frequency division multiplexing (OFDM) signal is proposed. Firstly, according to the channel frequency response vector of each array element, the algorithm reconstructs the vector data with delay and angle parameter information from both frequency and space dimensions. Then the enhanced data matrix for the extended array element is constructed, and the parameter vector of time delay and angle is estimated by the two-dimensional matrix pencil (2D MP) algorithm. Finally, the joint estimation of two-dimensional parameters is accomplished by the parameter pairing. The algorithm does not need a pseudo-spectral peak search, and the location of the target can be determined only by a single receiver, which can reduce the overhead of the positioning system. The theoretical analysis and simulation results show that the estimation accuracy of the proposed method in a single snapshot and low signal-to-noise ratio environment is much higher than that of Root Multiple Signal Classification algorithm (Root-MUSIC), and this method also achieves the higher estimation performance and efficiency with lower complexity cost compared to the one-dimensional matrix pencil algorithm.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.279-286
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• 2013

This paper introduces a new method for identification of building energy performance problems. The presented method is based on automated analysis and visualization of deviations between actual and expected energy performance of the building using EPAR (Energy Performance Augmented Reality) models. For generating EPAR models, during building inspections, energy auditors collect a large number of digital and thermal imagery using a consumer-level single thermal camera that has a built-in digital lens. Based on a pipeline of image-based 3D reconstruction algorithms built on GPU and multi-core CPU architecture, 3D geometrical and thermal point cloud models of the building under inspection are automatically generated and integrated. Then, the resulting actual 3D spatio-thermal model and the expected energy performance model simulated using computational fluid dynamics (CFD) analysis are superimposed within an augmented reality environment. Based on the resulting EPAR models which jointly visualize the actual and expected energy performance of the building under inspection, two new algorithms are introduced for quick and reliable identification of potential performance problems: 1) 3D thermal mesh modeling using k-d trees and nearest neighbor searching to automate calculation of temperature deviations; and 2) automated visualization of performance deviations using a metaphor based on traffic light colors. The proposed EPAR v2.0 modeling method is validated on several interior locations of a residential building and an instructional facility. Our empirical observations show that the automated energy performance analysis using EPAR models enables performance deviations to be rapidly and accurately identified. The visualization of performance deviations in 3D enables auditors to easily identify potential building performance problems. Rather than manually analyzing thermal imagery, auditors can focus on other important tasks such as evaluating possible remedial alternatives.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.271-279
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• 2016

The recent development of the HD (High Definition) and UHD (Ultra High Definition) technology allowed the growth of 3D contents market. Yet the majority of the 3D contents in the market are strictly for 6.5 cm inter-ocular distance, causing various visual discomforts for the viewers who have different inter-ocular distance. Moreover, because the 3D contents are created for a fixed viewing distance, the change of the viewing distances when watching 3D contents can also cause visual conflicts. To solve this problem, we devised techniques that consider the environmental information of the viewer watching 3D contents. By analyzing the relationship between viewing distance, inter-ocular distance, and perceived depth, we created an adaptive content viewing system that reflects the viewer's environment to minimize any conflicts in watching 3D contents. From our experiments, we found that the performance of our adaptive content viewing system was reasonable.

• 한국정보교육학회:학술대회논문집
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• 2004.08a
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• pp.446-453
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• 2004

기존의 과학 실험 활동은 도구 조작과 데이터 수집을 하기 위한 절차로서 컴퓨터를 이용한 예가 극히 적었다. 이런 점에 착안하여 다양한 센서를 활용하고 센서를 포함한 로보틱스를 도입하여 새로운 실험 실습 환경을 설계하고자 한다. 본 연구는 고학년을 중심으로 7차 과학과 교육과정에서 센서를 적용할 수 있는 교육 내용을 선정한 후 마이크로 컨트롤러를 이용하여 측정값을 디지털 세그먼트로 나타내고 또한 실험결과를 모니터 상에 그래프로 표현함으로써 학습자의 흥미와 호기심을 유발하고, 데이터 수집의 신속성과, 수업시간 운영의 효율성, 빠른 피드백을 가능하게 할 것이다.

• Journal of Korea Game Society
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• v.2 no.1
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• pp.36-41
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• 2002

Recently, The online role playing games (RPG) get into spotlight of worldwide game marketing area because of the rapid growth of high speed Internet environment during a decade. The almost online RPGs are made of campaign scenario that constructed in series. In this paper, we propose the Distributed Server Model for the Evolutionary Online RPGs which have series scenario (Campaign). In order to represents evolutionary online RPGs, We configure the online RPG server uniquely by means of one to one mapping between logical and physical game world. We also configure the game worlds using circular queue form to express the evolution of civilization by reconstruction of game world.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.125-133
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• 2017

Color in an image is determined by illuminant and surface reflectance. So, to recover unique color of object, estimation of exact illuminant is needed. In this study, the illumination models suggested to get the object color constancy with the physical illumination model based on physical phenomena. Their characteristics and application limits are presented and the necessity of an extended illumination model is suggested to get more appropriate object colors recovered. The extended illumination model should contain an additional term for the ambient light in order to account for spatial variance of illumination in object images. Its necessity is verified through an experiment under simple lighting environment in this study. Finally, a reconstruction method for recovering input images under standard white light illumination is experimented and an useful method for computing object color reflectivity is suggested and experimented which can be induced from combination of the existing illumination models.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.41-46
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• 1998

An image processing techniques for image compression and its reconstruction are to be considered seriously for the generated huge size data as in the present multimedia environment based on the graphics. So far some approaches for this matter are proposed such as a Wavelet and JPEG method and got desirable result. In this paper, we have studied for the rms(root mean square) metric which is more effective than the existing sup(supremum)metric, and compared with sup metric by means of mathematical verification.

• Journal of Korea Multimedia Society
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• v.19 no.5
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• pp.874-880
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• 2016

The gesture classification has been applied to many fields. But it is not efficient in the environment for game interface with low specification devices such as mobile and tablet, In this paper, we propose a effective way for realistic game interface using k-nearest neighbors algorithm for gesture classification. It is time consuming by realtime rendering process in game interface. To reduce the process time while preserving the accuracy, a reconstruction method to minimize error between training and test data sets is also proposed. The experimental results show that the proposed method is better than the conventional methods in both accuracy and time.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2003.05a
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• pp.174-177
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• 2003

The progress of urbanization has been accelerated by the development of machinery after the Industrial Revolution and the speed of change has been increased after the invention of computers. However, the problem of residence, the space for human life in the city, is still not complete. Ever since apartments rose as a solution for the residential problem caused by urbanization after the 1970s and now after 30 years, remodelling is preferred among the 2 choices, reconstruction and remodelling of apartments, in respect of economy and efficiency. Especially, in remodelling collective residence, construction, equipment environment, sight, etc. are considered and only after testing these various aspects can remodelling succeed. Aiming at studying the need of visual identity among many considerations in remodelling, this study investigates and analyzes the remodelling cases of domestic and overseas common residence and suggests the need of visual identity. In Korea where construction design for common residence is monotonous, expressing visual identity can be even more important. The common residence area that symbolizes its unique characteristic will elevate not only its economic value but also the psychological value of its residents.