• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.493-496
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• 2009

Many AR (Augmented Reality) applications have been interested in a marker-less tracking since the tracking methods give camera poses without attaching explicit markers. In this paper, we propose a new marker-less page recognition and tracking algorithm for an AR book application such as DigilogBook. The proposed method only requires orthogonal images of pages, which need not to be trained for a long time, and the algorithm works in real-time. The page recognition is done in two steps by using SIFT (Scale Invariant Feature Transform) descriptors and the comparison evaluation function. And also, the method provides real-time tracking with 25fps ~ 30fps by separating the page recognition and the frame-to-frame matching into two multi-cores. The proposed algorithm will be extended to various AR applications that require multiple objects tracking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5307-5327
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• 2016

Restricted by finite battery energy, traditional wireless sensor networks (WSNs) can only maintain for a limited period of time, resulting in serious performance bottleneck in long-term deployment of WSN. Fortunately, the advancement in the wireless energy transfer technology provides a potential to free WSNs from limited energy supply and remain perpetual operational. A mobile charger called wireless charging vehicle (WCV) is employed to periodically charge each sensor node and keep its energy level above the minimum threshold. Aiming at maximizing the ratio of the WCV's vocation time over the cycle time as well as guaranteeing the perpetual operation of networks, we propose a feasible and optimal solution to this issue within the context of a real-time large-scale deployed WSN. First, we develop two different types of charging cycles: initialization cycles and renewable cycles and give relevant algorithms to construct these two cycles for each sensor node. We then formulate the optimization problem into an optimal construction algorithm and prove its correctness through theoretical analysis. Finally, we conduct extensive simulations to demonstrate the effectiveness of our proposed algorithms.

• Journal of Communications and Networks
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• v.17 no.2
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• pp.100-109
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• 2015

Mobile phone carriers face challenges from three synergistic dimensions: Wireless, social, and mobile. Despite significant advances that have been made about social networks and human mobility, respectively, our knowledge about the interplay between two layers remains largely limited, partly due to the difficulty in obtaining large-scale datasets that could offer at the same time social and mobile information across a substantial population over an extended period of time. In this paper, we take advantage of a massive, longitudinal mobile phone dataset that consists of human mobility and social network information simultaneously, allowing us to explore the impact of human mobility patterns on the underlying social network. We find that human mobility plays an important role in shaping both local and global structural properties of social network. In contrast to the lack of scale in social networks and human movements, we discovered a characteristic distance in physical space between 10 and 20 km that impacts both local clustering and modular structure in social network. We also find a surprising distinction in trajectory overlap that segments social ties into two categories. Our results are of fundamental relevance to quantitative studies of human behavior, and could serve as the basis of anchoring potential theoretical models of human behavior and building and developing new applications using social and mobile technologies.

• Korean Journal of Hydrosciences
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• v.8
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• pp.57-68
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• 1997

The daily soil water contents were obtained from the time domain reflectometry(TDR) method and energy balance-water budget approach with eddy correlation at the two small semiarid watersheds of Lucky Hills and Kendall during the summer rainy period. There was a comaprison of daily soil water content measured and estimated from these two different approaches. The comparison is valuable to evaluate the accuracy of current soil water content measuring system using TDR and energy balance-water budget approach using eddy correlation method at a small watershed scale. The degree of simiarity between the regressions of these two methods of measuring soil water content was explained by determining the correlations between these methods. Simple linear regression analyses showed that soil water content measured from TDR method was responsible for 58% and 63% of the variations estimated from energy balance-water budget approach with edy correlation at Lucky Hills and Kendall, respectively. The scatter plots and the regression analyses revealed that two different approaches for soil water content measurement at a small watershed scale have no significant difference.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.440-445
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• 1993

A two dimensional large scale laser digitizer with a cordless cursor was developed. The coordinate detecting scheme of this digitizer is fundamentally based on the triangulation method, in which two laser-rays are scanned by the rotating plane mirros, reflected backward by the cursor, reflected again by the rotating mirrors, and detected by optical sensors. From angles in which the cursor reflections are detected, we can determine the position of the cursor. But this method involves several problems about optical alignment and its calibration especially when it is applied to a large scale digitizer. In this paper, especially we propose simulation for error analysis with connection to angles measured at five control points which are needed to decide an appropriate model for calculating coordinates and optimal simulation for deciding the position of five control points to give the better coordinate accuracy. In this way, we realized the on-site calibration and on-site insurance of measurement accuracy with our appropriate model for calculating coordinates. The time required for on-site calibration is within 5 minutes and the average accuracy of 4m * 3m digitizer is about .+-.0.12mm.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.109-116
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• 1994

Quickness and precision are the two most important requirements for an industrial scale used in production lines. In this paper, a new approach, "Dynamic-Mass measurement control System of Acceleration and Displacement(DMS-AD) sensing", is presented to improve some of drowbacks in conventional scales. The system, consisted of acceleration and displace- ment sensors, spring scale and microcomputer, is based on full utilization of dynamic mass measurement of acceleration and displacement via microcomputer-assisted real time monitoring. The rsulting system, when combined with appropriate dynamic mass estimation algorithm software, has shown its effectiveness in terms of two desirable characteristics required. required.

• Journal of the Korean Home Economics Association
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• v.18 no.3
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• pp.29-34
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• 1980

The purpose of this study is to clarify the effects of mother's occupation on the personality of the child. for the purpose of this study, the Minnesota multiphastic Personality Inventory were administered to 33 boy students with employed mothers and another 33 whose mothers spened full time as house wife selected from two high schools located in Seoul. -test were employed for the statistical analysis of the data and the following are the findings: 1. In general working mother does not have any remarkable influence on personality of the child. 2. There is no significant difference between two groups except on scale, Sc scale, and Hs scale. 3. It may not be the mother's occupation but her attitude that influences the child's personality.

• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.59-64
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• 2013

Accurate and robust image registration is important task in many applications such as image retrieval and computer vision. To perform the image registration, essential required steps are needed in the process: feature detection, extraction, matching, and reconstruction of image. In the process of these function, feature extraction not only plays a key role, but also have a big effect on its performance. There are two representative algorithms for extracting image features, which are scale invariant feature transform (SIFT) and speeded up robust feature (SURF). In this paper, we present and evaluate two methods, focusing on comparative analysis of the performance. Experiments for accurate and robust feature detection are shown on various environments such like scale changes, rotation and affine transformation. Experimental trials revealed that SURF algorithm exhibited a significant result in both extracting feature points and matching time, compared to SIFT method.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.47-55
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• 1999

Recently, the treatment of that wastes according to increase of food waste has been a great problem of modern society for long time. This study was aimed to evaluate possibility for food waste and sewage sludge mixture treatment using pilot scale two-phase anaerobic digester. Pilot scale two-phase anaerobic digestion system was performanced at 1 : 9 mixture ratio of food waste and sewage sludge infield. The detention time of digester was 20days. The average COD and VS removal efficiencies in organic loading rate $3.03kg\;TCOD/m^3-day$ were 57.7 and 47.7%, and the gas production rate and methane content were $0.4m^3/kg$ VS-day and 65.3%, respectively. TS, VS and VS/TS(%) of mixing tank were 4.44%, 2.59% and 58.34%, respectively and TS. VS and VS/TS(%) of digester in steady state were 3.32%, 1.39% and 41.90%, respectively, Through this study. it was possible to accomplish effective mixture treatment of the sewage sludge and food waste.

• Solar Energy
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• v.18 no.3
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• pp.197-203
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• 1998

A 5 ton/day pilot scale two-phase anaerobic digester was constructed and tasted to treat Korean food wastes in Anyang city. The process was developed based on 3 years of lab-scale experimental results on am optimim treatment method for the recovery of biogas and humus. Problems related to food waste are ever Increasing quantity among municipal solid wastes(MSW) and high moisture and salt contents. Thus our food waste produces large amounts of leachate and bed odor in landfill sites which are being exhausted. The easily degradable presorted food waste was efficiently treated in the two-phase anaerobic digestion process. The waste contained in plastic bags was shredded and then screened for the removal of inert material such as fabrics and plastics, and subsequently put into the two-stage reactors. Heavy and light inerts such as bones, shells, spoons and plastic pieces were again removed by gravity differences. The residual organic component was effectively hydrolyzed and acidified in the first reactor with 5 days space time at pH of about 6.5. The second, methanization reactor part of which is filled with anaerobic fillters, converted the acids into methane with pH between 7.4 to 7.8. The space time for the second reactor was 15 days. The effluent from the second reactor was recycled to the first reactor to provide alkalinities. The process showed stable steady state operation with the maximum organic rate of 7.9 $kgVS/m^3day$ and the volatile solid reduction efficiency of about 70%. The total of 3.6 tons presorted MSW containing 2.9 tons of food organic was treated to produce about $230m^3$ of biogas with 70% of methane and 80kg humus. This process is extended to full scale treating 15 tons of food waste a day in Euiwang city and the produced biogas is utilized for the heating/cooling of adjacent buildings.