• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1165-1168
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• 2005

This paper proposes an digital image watermarking method based on discrete wavelet transform(DWT) and spatial perceptual properties of human visula system. first, an digital image is transformed by DWT and inserted gaussian watermark into the frequency domain. To increase the robustness and perceptual invisibility of watermark, the proposed algorithm is combined with the characteristics of digital image and human visual system. The proposed method is invisible and blind watermarking which the original image is not required to detect watermarks. Simulation results show that the proposed method is robust to the general attack such as JPEG compression, enhancement, noise, cropping, and filtering etc.

• The korean journal of orthodontics
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• v.49 no.3
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• pp.140-149
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• 2019

We are currently living in an era where the use of computer-aided design/computer-aided manufacturing has allowed individualized orthodontic treatments, but has also incorporated enhanced digitalized technology that does not permit improvisation. The purpose of this systematic review was to analyze publications that assessed the accuracy and efficiency of the $Invisalign^{(R)}$ system. A systematic review was performed using a search strategy to identify articles that referenced $Invisalign^{(R)}$, which were published between August 2007 and August 2017, and listed in the following databases: MEDLINE, Embase, Cochrane Library, Web of Knowledge, Google Scholar, and LILACS. Additionally, a manual search of clinical trials was performed in scientific journals and other databases. To rate the methodological quality of the articles, a grading system described by the Swedish Council on Technology Assessment in Health Care was used, in combination with the Cochrane tool for risk of bias assessment. We selected 20 articles that met the inclusion criteria and excluded 5 due to excess biases. The level of evidence was high. Although it is possible to treat malocclusions with plastic systems, the results are not as accurate as those achieved by treatment with fixed appliances.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1388-1391
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• 2010

In this paper, we present a design and implementation of U-learning system using pen based augmented reality approach. Student has been given a smart pen and a smart study book, which is similar to the printed material already serviced. However, we print the study book using CMY inks, and embed perceptually invisible dot patterns using K ink. Smart pen includes (1) IR LED for illumination, IR pass filter for extracting the dot patterns, and (3) camera for image captures. From the image sequences, we perform topology analysis which determines the topological distance between dot pixels, and perform error correction decoding using four position symbols and five CRC symbols. When a student touches a smart study books with our smart pen, we show him/her multimedia (visual/audio) information which is exactly related with the selected region. Our scheme can embed 16 bit information, which is more than 200% larger than previous scheme, which supports 7 bits or 8 bits information.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.15-23
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• 2009

In ubiquitous environments, invisible devices and software are connected to one another to provide convenient services to users. In this environments, users want to get a variety of customized services by using only an individual mobile device which has limitations such as tiny display screens, limited input, and less powerful processors. Therefore, The device sharing for solving these limitation problems and its efficient processing is one of the new research topics. This paper proposes a device recommender system which searches and recommends devices for composing user requested services. The device recommender system infers devices based on environmental context of a user. However, customized devices for each user are different because of a variety of user preference even if users want to get the same service in the same space, Therefore the paper considers the user preference for device recommendation. Our device recommender system is implemented and tested on the real mobile object developed for device sharing in ubiquitous environments. Therefore we can expect that the system will be adaptable in real device sharing environments.

• Fire Science and Engineering
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• v.27 no.6
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• pp.115-121
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• 2013

Industrial facilities are becoming bigger and more up to date, And a kind of the hazardous material used in the industrial filed is diversified. Therefore, serious accidents such as leakage of toxic materials, fire and explosion, is continuously occurred. There is Process Safety Management (PSM) system of the several preventive systems, but it is supposed to be a limitation to ensure safety or huge PSM industrial sites where have potential to catastrophically invisible and unexpected risks because it is still being managed by instruction and inspection of authority having jurisdiction other than self-regulating management differing from the primarily aim of PSM system. To verify safety management system of work-place, supplementation of existing system is urgently required. In this study, it suggests that PSM self-audit be emphasized significantly analyzing problems of the current systems for enhancing self-audit be emphasized significantly analyzing problems of the current systems for enhancing self-control safety through efficient self-audit management and improving the existing system and improving the existing as verifying the system there of, as well as studying methods which can support institutionally.

• Journal of the Korea Society of Computer and Information
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• v.7 no.1
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• pp.161-173
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• 2002

The increasing disposable time through advancing information has come to make the tourism industry as well as the information communication industry glow in the 21st century We cannot make rational decision without proper guide information. It is impossible to anticipate tourism Products which are invisible products consisting of a variety of basic combinations of products. Tourists are getting dissatisfied with tourism experts' distorted guidance every year. A recent survey shows that the current tourism information system can't meet the need of tourists who are informative and individualized. This paper presents tourism information system that offers the most appropriate tour courses depending on the tastes of tourists by utilizing expert system, artificial intelligent applied technology. This paper is the first attempt to maximize comsumer satisfaction by developing the intelligent agent system that is able to reflect the traits of individualized customers' in the tourism industry The establishment of this system will contribute to activating the tourism industry, ultimately, by decreasing inconveniencies and tour schedules appropriate to the purpose of individual tours.

• Journal of the Korea Society of Computer and Information
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• v.26 no.5
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• pp.23-30
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• 2021

In this paper, we propose an extended reality-based simultaneous multi presence system in a process of remote cooperative work. The proposed system generates a ring-shaped invisible screen which surrounds a user, and it provides position and manipulation of remote workspace and personal workspace. With the proposed system, the user easily navigates the several workspace for the remote collaboration or he/she selects a specific space for immersion. The proposed system also provides manipulation of personal workspace for the user during the remote cooperative work. We conducted a user study to prove effectiveness of the proposed system. According to the results, the proposed system increased understanding spatial information and usage of time during the remote cooperative work.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.324-333
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• 2005

Distraction osteogenesis for the advancement of hypoplastic maxilla of cleft patients has shown successful results. In this report, rigid external distraction(RED) system and internal distraction device were used for maxillary advancement. Each system has its advantages and disadvantages. Larger amount of advancement can be achieved with RED system. But complex external device may give patients psychological stress. Internal device is invisible. However its distraction amount have limitation for the advancement (< 20mm) and the vector cannot be changed freely during distraction. The authors treated five cleft patients with maxillary hypoplasia(three with RED system and two with internal distractor). Their results were clinically satisfactory. We present the pros and cons of RED and internal system for maxillary distraction osteogenesis.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1131-1135
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• 2010

This paper presents a method to capture the posture of the human lower-limbs on the 3D space by using a single camera and a planar mirror. The system estimates the pose of the camera facing the mirror by using four coplanar IR markers attached on the planar mirror. After that, the training space is set up based on the relationship between the mirror and the camera. When a patient steps on the weight board, the system obtains relative position between patients' feet. The markers are attached on the sides of both legs, so that some markers are invisible from the camera due to the self-occlusion. The reflections of the markers on the mirror can partially resolve the above problem with a single camera system. The 3D positions of the markers are estimated by using the geometric information of the camera on the training space. Finally the system estimates and visualizes the posture and motion of the both legs based on the 3D marker positions.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.623-629
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• 2003

In this paper, we have proposed a full phase encryption scheme based on phase-encoded XOR operation. The proposed scheme encrypts a gray-level image by slicing an original image and combining with XORed images which resulted from phase-encoded XOR operations between sliced images and phase-encoded binary random images. Then we produce an encrypted image by combining only XORed images and a key image by only phase-encoded binary random images. The encrypted image and key image are converted into encrypted data and key data by a phase-encoding method. The merits are that the proposed encryption scheme can basically fulfill a high-level encryption using a full phase encryption scheme which has nonlinear and invisible characteristics. The scheme also improves security by encrypting the phase information before full phase encryption. The decryption system based on the principle of interference between a reference wave and a direct pixel-to-pixel mapping image of encrypted data with key data can be simply implemented using a phase-visualization system. Simulation results indicate that our proposed encryption scheme is effective and simple for a gray-scale image and optical decryption system.