• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.577-580
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• 2010

This paper proposes a new algorithm for flicker reduction. Flicker is defined as unwanted luminance fluctuation in the image sequences. As the flicker degrades the performance of motion estimation or segmentation of the objects, it should be corrected before further processing. In this paper, we model the flicker effects as a linear system with gain and offset parameter and propose the new algorithm for flicker reduction. The proposed algorithm considers gain and offset parameter separately, and stabilizes the luminance fluctuation based on these parameters. We show the performance of the proposed method by testing on the sequence with artificially added luminance flicker and real sequence with object motion.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.291-297
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• 2006

This paper presents a new anti-copying methode for hard copy documents. The approach protects the document and its content from unauthorized copying and forgeries, while using ordinary paper and ordinary printer. The paper copy is protected against copying as the photocopy version will appear differently when compared to the authorized printed original hard copy using Human Visual System. The anti-copying pattern created through pointillism with a halftone cell and a spot. The proposed method is useful for unauthorized copying and forgeries with high-resolution scanners and photocopiers.

• Journal of the Korea Computer Graphics Society
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• v.30 no.3
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• pp.43-49
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• 2024

Hand tracking is currently one of the most promising technologies in XR with the release of extended reality (XR) devices, in which hand tracking is used as the main manipulation. Hand tracking offers advantages in terms of immersion and realism, and as a result, it is being employed in a range of fields, including education, business, and medical care. The archery movement requires using both hands at the same time, but requires sophistication to hit the target and is a movement that has cultural and sports significance in the past. This study aimed to implement this archery movement. Therefore, this paper used the XR Hands package provided by Unity to recognize hand movements, explored the underlying OpenXR, and finally implemented the archery movement and tested it in Meta Quest 2.

• The Journal of the Acoustical Society of Korea
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• v.30 no.4
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• pp.181-189
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• 2011

According to developments of digital signal processing, 3D sound come into focus on multimedia systems. Many studies on 3d sound have proposed lots of clues to create realistic sounds. But these clues are only focused on binaural systems which two ears are normal. If we make the 3d sound using those clues at monaural systems, the performance goes down dramatically. In order to use the clues for monaural systems, we have studies algorithms such as duplex theory. In duplex theory, the sounds that we listen are affected by human's body, pinna and shoulder. So, we can enhance sound localization performances using its characteristics. In this paper, we propose a new method to use psychoacoustic theory that creates realistic 3D audio at monaural systems. To improve 3d sound, we calculate the excitation energy rates of each symmetric HRTF and extract the weights in each bark range. Finally, they are applied to emphasize the characteristics related to each direction. Informal listening tests show that the proposed method improves sound localization performances much better than the conventional methods.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.63-71
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• 2012

This paper presents a design and implementation of U-Seum(Ubiquitous Museum) system based on the LBS(Location Based Service) and mobile augmented reality technique. The mobile services under the smart space of the ubiquitous environments have been expanded in the various fields. In this study, we introduce U-Seum which supports tourists in the museum. U-Seum is developed by use of the position tracking technique based on Wi-Fi and mobile augmented reality. The GPS which is widely used in the position tracking has a difficulty to be utilized in the inside of the building because it requires the Line-of-Sight between a sender and a receiver. Therefore, in this paper, we develop a realtime tour-supported service through experience and evaluate the performance of the system in the world famous UNESCO's Hwa-Seong Museum by measuring the distance from the Wi-Fi signal which is suitable to track the position interior of the museum. U-Seum provides various push services such as mobile augmented reality service for explanation of the artifacts of the museum, game services and the statistics information of the tourist when the tourist approach a specific AP. U-Seum is developed in the Haw-Seong Museum by the support of the Swon Haw-Seong Cultural Foundation. With a field test, we prove that the excellence and expandability of the system.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.158-177
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• 2024

This paper proposes and tests a theoretical model of the relational link between a novel form of customer-perceived fairness for a reward design (distributive peer justice climate) and C2C helping intention via community identification and online C2C interaction (friend-, neighboring customer-, audience-interaction) qualities in a collective consumption context (MMORPG). To test hypotheses, we amassed survey data within a collective consumption context (massively multiplayer online role-playing games, MMORPGs). We used structural equation modeling in analyzing the survey data. The results reveal that user-perceived distributive peer justice climate for a reward design enhances their C2C helping intention via community identification and C2C interactions in MMORPG contexts. Collective consumption-type service managers should focus on promoting the user-perceived distributive peer justice climate for their reward system to enhance users' present C2C co-creation experience (community identification, C2C interaction) and future C2C co-creation behavior (helping intention). By adopting an intra-unit level distributive justice concept (customer-perceived distributive peer justice climate) to a reward design in a collective consumption context (MMORPGs), this study informed collective consumption-type service managers of the importance of its management.

• Composites Research
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• v.18 no.1
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• pp.45-54
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• 2005

The delamination in the filament-wound composite flywheel rotor often lowers the performance of the flywheel energy storage system. A conventional ring type hub usually causes tensile stresses on the inner surface of the composite rotor, resulting in lowering the maximum rotational speed of the rotor. In this work, the stress and strain distributions within a hybrid composite rotor were derived from the two-dimensional governing equation with the specified boundary conditions, and an optimum pressure at the inner surface of the rotor was proposed to minimize the strength ratio and maximize the storage energy. A split type hub was introduced to apply the calculated optimum pressure at the inner surface, and a spin test was performed up to 40,000 rpm to demonstrate the performance of the split type hub with radial and circumferential strains measured using a wireless telemetry system. From the analysis and the test, it was found that the split type hub successfully generates a compressive pressure on the inner surface of the rotor, which can enhance the performance of the composite rotor by lowering the strength ratio within the rotor.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.2
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• pp.177-184
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• 2017

Many ground subsidence accidents have happened in Korea. The accident was caused by the subsidence and leakage of the deteriorated sewage pipe. This study aims to establish the empirical data of the ground penetration radar(GPR) detection for ground subsidence. A test bed was also manufactured for the same purpose. The GPR detection variables are embedment depth and horizontal distance of embedded cast iron pipe and expanded polystyrene(EPS). From the detection results, the EPS embedded by a depth of 1.5m was difficult for detection. The EPS closely embedded to the cast iron pipe within a 0.5m distance had a very strong cast iron pipe signal. Therefore, the detection was impossible. This study developed an image processing program, called the GPR image processing program(GPRiPP), to process the GPR detection results. Its major function is the gain function, which amplifies the wiggle wave signal. Compared to the existing programs, the GPRiPP is capable of showing a similar image processing performance.

• The KIPS Transactions:PartA
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• v.14A no.2
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• pp.125-132
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• 2007

Recently, in the engineering area, there is an increasing need for researchers at a distance to share the result of the experiment, without having to visit the experiment facilities. Especially in the civil engineering, researchers feel the need for participating in a experiment conducted at a distant location. In addition, it is suggested that high-cost facilities should be used by remote researchers thereby increasing the utilization rate. This paper proposes a remote experiment environment in civil engineering that are being developed in a project called Korea Construction Engineering Development(KOCED), which connects major civil engineering experiment facilities using grid technology, allows researchers to participate in a remote experiment, and has the experiment results shared by remote researchers automatically. Then, based on the suggested environment, we designed a hybrid test facility that involves two physical experiment facility sites and one numerical simulation site that are geographically apart. Then, we implemented its prototype and ran some tests, which showed a possibility of grid-based civil engineering experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.484-490
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• 2016

Full-duplex communication can enhance wireless capacity by enabling simultaneous transmission and reception of the signals on the same frequency spectrum. Such a benefit, however, is only achieved when strong self-interference is well canceled below a sufficient level. To achieve this goal, there have been several approaches for cancellation, each of which is combined with digital-domain cancellation for a higher gain. In this paper, we implement two self-interference cancellation techniques and integrate them with a software defined radio-based wireless communication testbed. Two cancellation techniques (antenna cancellation and noise subtraction) are implemented and the cancellation gain is measured via real experiments. The results show that the gain of the antenna placement technique highly depends on the placement of a receiving antenna and the highest gain is achieved at the expected point, and we show that combining the noise subtraction circuit with the antenna placement further improves the cancellation gain.