• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.1-9
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• 2023

For optimal image quality of computer tomography angiography (CTA), different iodine concentrations and scan parameters were applied to quantitatively evaluate the image quality characteristics of filtered back projection (FBP), hybrid-iterative reconstruction (hybrid-IR), and deep learning reconstruction (DLR). A 320-row-detector CT scanner scanned a phantom with various iodine concentrations (1.2, 2.9, 4.9, 6.9, 10.4, 14.3, 18.4, and 25.9 mg/mL) located at the edge of a cylindrical water phantom with a diameter of 19 cm. Data obtained using each reconstruction technique was analyzed through noise, coefficient of variation (COV), and root mean square error (RMSE). As the iodine concentration increased, the CT number value increased, but the noise change did not show any special characteristics. COV decreased with increasing iodine concentration for FBP, adaptive iterative dose reduction (AIDR) 3D, and advanced intelligent clear-IQ engine (AiCE) at various tube voltages and tube currents. In addition, when the iodine concentration was low, there was a slight difference in COV between the reconstitution techniques, but there was little difference as the iodine concentration increased. AiCE showed the characteristic that RMSE decreased as the iodine concentration increased but rather increased after a specific concentration (4.9 mg/mL). Therefore, the user will have to consider the characteristics of scan parameters such as tube current and tube voltage as well as iodine concentration according to the reconstruction technique for optimal CTA image acquisition.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.6
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• pp.57-69
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• 2001

Expert system is one of AI area. It simulates the human's way of thinking to give solutions of problem in many applications. Most expert system consists of many components such as inference engine, knowledge base, and so on. Especially the performance of expert system depend on the control of efficiency of inference engine. Inference engine has to get features; first, if possible to minimize restrictions when it constructed the knowledge base. second, it has to serve various kinds of inferencing methods. In this paper we propose knowledge scheme for representing domain knowledge in ease, knowledge implementation technique for inferencing, and integrated knowledge-base engine with blackboard and inference engine. And we describe a expert system prototype that implemented in this paper using proposed methods, it perform diagnose about heavy industrial device. The fault diagnosis system prototype has been studied in this paper will be practical foundation in the research area of knowledge based system.

• Journal of Korea Game Society
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• v.17 no.1
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• pp.7-16
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• 2017

The 3D game graphic technology has become an important factor in the contents field with the game contents development. In particular, game character technology provides a realistic technique and visual pleasure, as well as an intermediate step in the immersion of the game in which the game might create an optical illusion that enables the player to enjoy heroic adventure in the game. The high expression level of characters in 3D games is a key factor in the development process, with details and carefulness of the character setting work [3]. In this paper, we propose a character representative technique applied to mobile games using mathematical model of radiosity energy, spectral radiance model, and ray tracing model method using 3D unity game engine with sensible AI algorithm for game implementation. As a practical application to the game contents, it was found that the projection of the surface in the rendering process and the game simulation might change according to the lighting condition of the game content environment, so that the high quality of game characters was simulated.

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.163-170
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• 2022

With the advent of the 4th Industrial Revolution, solutions that apply AI technology are being actively developed. Since 2017, the introduction of business automation solutions using AI-based Robotic Process Automation (RPA) has begun in the financial sector and insurance companies, and recently, it is entering a time when it spreads past the stage of introducing RPA solutions. Among the business automation using these RPA solutions, it is very important how accurately textual information in the document is recognized for business automation using various documents. Such character recognition has recently increased its accuracy by introducing deep learning technology, but there is still no recognition model with perfect recognition accuracy. Therefore, in this paper, we checked how much accuracy is improved when pre- and post-processor technologies are applied to deep learning-based character recognition engines, and implemented RPA recognition engines and linkage technologies.

• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.23-29
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• 2022

Virtual humans are implemented with dedicated modeling tools like Unity 3D Engine in virtual space (virtual reality, mixed reality, metaverse, etc.). Various human modeling tools have been introduced to implement virtual human-like appearance, voice, expression, and behavior similar to real people, and virtual humans implemented via these tools can communicate with users to some extent. However, most of the virtual humans so far have stayed unimodal using only text or speech. As AI technologies advance, the outdated machine-centered dialogue system is now changing to a human-centered, natural multi-modal system. By using several pre-trained networks, we implemented an emotion-based multi-modal dialogue system, which generates human-like utterances and displays appropriate facial expressions in real-time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.119-124
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• 2017

In 1997, IBM's DeepBlue won the world chess championship, Garry Kasparov, and recently, Google's AlphaGo won all three games against Ke Jie, who was ranked 1st among all human Baduk players worldwide, interest in deep running has increased rapidly. DeepPurple, proposed in this paper, is a AI chess engine based on deep learning. DeepPurple Chess Engine consists largely of Monte Carlo Tree Search and policy network and value network, which are implemented by convolution neural networks. Through the policy network, the next move is predicted and the given situation is calculated through the value network. To select the most beneficial next move Monte Carlo Tree Search is used. The results show that the accuracy and the loss function cost of the policy network is 43% and 1.9. In the case of the value network, the accuracy is 50% and the loss function cost is 1, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.680-685
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• 2006

The latest trend in the automotive industry demands the development of high stiffness car bodies and the securement of inter-system performance for low vibration and noise vehicles. This demand, however, conflicts with need for light weight design and greater fuel efficiency, thus raising the importance of optimization design to satisfy both developmental goals. We chose two European medium sedans, which has gasoline engine and diesel one, to elucidate the noise characteristics of diesel passenger cars, whose sales have been increasing in both Korea and Europe. In the present study a systematic experiment was conducted to analyze the noise characteristics in diesel cars. we made it possible for differentiating car management according to customer demand while allowing for improved commercial feasibility. it was possible to improve interior noise by 2 dB(A) on average sound pressure level. As a result, by 4% higher on articulation index(AI).

• International journal of advanced smart convergence
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• v.13 no.1
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• pp.23-36
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• 2024

Interest in virtual humans continues to increase due to the development of generative AI, extended reality, computer graphics technology, and the spread of a converged metaverse that goes beyond the boundaries between reality and virtuality. Despite the negative public opinion that virtual humans were just temporary form of entertainment event in the early days of their emergence, the reason they are showing continuous growth is due to the unique characteristics of virtual humans and the expansion of diverse usage from technological advancements. The production of video content using virtual humans is becoming vigorously active, but currently there is limitation and no exact process for the technology to apply virtual humans to video content for it to be produced accordingly to the characteristics or situations of virtual humans. In this study, we investigated the characteristics of virtual human production technology methods & processes, and identifying the impact of each production technology on the production environment through examples of virtual human content applied to domestic and international video contents. In conclusion, by proposing an appropriate production method for each content, we hope to develop and assist production practitioners so they can effectively use virtual humans in video content production.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.141-149
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• 2009

The oil pan is an important factor for the noise behavior of the engine system. In this paper a new Magnesium oil pan was designed and analyzed to replace the current Aluminium oil pan. Dynamic stiffness and sound pressure level of the newly designed Mg oil pan were compared with the AI oil pan using the finite element method. NVH characteristics of the Mg oil pan is slightly insufficient when we changed the material of the oil pan from Al to Mg without modifying the design. Some design modifications of the Mg oil pan resulted in equal or superior characteristics compared to the Al oil pan. New ribs were added to stiffen the structure of the Mg oil pan. Thickness of thin plate area was increased to reduce the radiated noise. Through the changes of shape, higher dynamic stiffness than the current Al oil pan were achieved. Results of frequency response analysis show that we can reduce the sound pressure level of the oil pan if we increase the thickness of the thin plate area. It is shown that the new Mg oil pan could reduce the weight of the engine system and improve NVH quality of an automobile.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.24-27
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• 2018

본 논문은 최신 가상현실 미디어 기술동향과 다양한 분야에서 시도해 온 VR 멀미저감 방안을 리뷰하여, 가상현실 사용자의 인지적 수용성을 높이는 방안에 대해 논의하였다. 이를 통해 최신 미디어 기술의 사용자 가치제안 방식을 분석하고 Social VR 플랫폼의 인지적 수용성을 개선하는 효율적 방안을 제안하였다. 생체신호 모니터링, VR 콘텐츠 적합도 분석, 멀미 메커니즘 조절, 신체동요측정 기반 멀미예측 등 다양한 멀미저감 방식 중 개발 비용과 사용자 수용성 측면에서 가장 효율적인 신체동요측정 기반 멀미예측 기술의 사전테스트 결과를 소개하고 적용 방안을 구체화하였다. 가상현실 체험 전 미세한 신체동요가 많은 사용자일수록 VR 멀미 민감도가 크게 증가하는 것을 확인하였다. 개인의 멀미민감도를 반영하는 본 측정 결과를 다양한 가상현실 환경에서 테스트하고 개인특성에 따른 VR 멀미 데이터베이스를 구축한다면 AI 기반의 멀미 예측기술을 구현하는데 크게 기여할 것으로 예상된다.