• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.52-54
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• 2009

This paper deals with design parameters deduction and analysis of hybrid magnetic bearing. Using the solutions obtained from equivalent magnetic circuit, we predict the electromagnetic characteristics from permanent magnet and electromagnet and obtain the initial parameters. And then, using non-linear finite element analysis, a detailed design is performed considering saturation and asymmetry of flux density at the surface in order to meet requirements.

• Journal of the Optical Society of Korea
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• v.9 no.4
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• pp.157-161
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• 2005

Medical infrared imaging is obtained by measuring the self-emitted infrared radiance from the human body. Infrared emission is related to surface temperature and temperature is one of the most important physiological parameters related to health. Though recent applications such as security identification and oriental medicine have provided new fields of biomedical applications, infrared thermography has had ups and downs in its usages in cancer detection. Some of the main difficulties include finding proper applications and efficient diagnostic algorithms. In this study, infrared thermal imaging was used to detect regional metastasis of breast cancer. Our measurements were done for 110 women. From 63 individuals of a Healthy Group and a Benign Breast Disease Group, we developed algorithms for differentiating malignant regional metastasis based on temperature difference and asymmetry of temperature distribution. Testing with 47 cancer patients, we achieved a positive predictive value of $87.5\%$ and a negative predictive value of $95.6\%$. The results were better than for mammogram examination. A proper analysis of infrared imaging proved to be a highly informative and sensitive method for differentiating regional cancer metastasis from normal regions.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.357-367
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• 2021

In general, common cause failures (CCFs) have been modeled with the assumption that components within the same group are symmetric. This assumption reduces the number of parameters required for the CCF probability estimation and allows us to use a parametric model, such as the alpha factor model. Although there are various asymmetric conditions in nuclear power plants (NPPs) to be addressed, the traditional CCF models are limited to symmetric conditions. Therefore, this paper proposes the copulabased CCF model to deal with asymmetric as well as symmetric CCFs. Once a joint distribution between the components is constructed using copulas, the proposed model is able to provide the probability of common cause basic events (CCBEs) by formulating a system of equations without symmetry assumptions. In addition, Bayesian inferences for the parameters of the marginal and copula distributions are introduced and Markov Chain Monte Carlo (MCMC) algorithms are employed to sample from the posterior distribution. Three example cases using simulated data, including asymmetry conditions in total failure probabilities and/or dependencies, are illustrated. Consequently, the copula-based CCF model provides appropriate estimates of CCFs for asymmetric conditions. This paper also discusses the limitations and notes on the proposed method.

• Archives of Craniofacial Surgery
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• v.22 no.6
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• pp.287-295
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• 2021

Orthognathic surgery has steadily evolved, gradually expanding its scope of application beyond its original purpose of simply correcting malocclusion and the facial profile. For instance, it is now used to treat obstructive sleep apnea and to achieve purely cosmetic outcomes. Recent developments in three-dimensional digital technology are being utilized throughout the entire process of orthognathic surgery, from establishing a surgical plan to printing the surgical splint. These processes have made it possible to perform more sophisticated surgery. The goal of this review article is to introduce current trends in the field of orthognathic surgery and controversies that are under active discussion. The role of a plastic surgeon is not limited to performing orthognathic surgery itself, but also encompasses deep involvement throughout the entire process, including the set-up of surgical occlusion and overall surgical planning. The authors summarize various aspects in the field of orthognathic surgery with the hope of providing helpful information both for plastic surgeons and orthodontists who are interested in orthognathic surgery.

• Current Optics and Photonics
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• v.6 no.2
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• pp.129-136
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• 2022

We propose a photonic crystal fiber (PCF) with a slotted porous core and elliptical-hole cladding, for high birefringence in the terahertz regime. Asymmetry in the guided mode is obtained mainly by using arrays of elliptical air holes in the TOPAS^® polymer cladding. We investigate the tradeoff between several structural parameters and find optimized values that can have a high birefringence while satisfying the single-mode condition. The optical properties in the terahertz regime are thoroughly analyzed in numerical simulations, using a full-vector finite-element method with the perfectly-matched-layer condition. In an optimal design, the proposed photonic crystal fiber shows a high birefringence of 8.80 × 10^-2 and an effective material loss of 0.07 cm^-1 at a frequency of 1 THz, satisfying the single-mode-guidance condition at the same time. The proposed PCF would be useful for various polarization-management applications in the terahertz range.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3320-3325
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• 2023

The scaled water-cooled Reactor Cavity Cooling System (RCCS) experimental facility reproduces a passive safety feature to be implemented in Generation IV nuclear reactors. It keeps the reactor cavity and other internal structures in operational conditions by removing heat leakage from the reactor pressure vessel. The present work uses Flownex one-dimensional thermal-fluid code to model the facility and predict the experimental thermal-hydraulic behavior. Two representative steady-state cases defined by the bulk volumetric flow rate are simulated (Re = 2,409 and Re = 11,524). Results of the cavity outlet temperature, risers' temperature profile, and volumetric flow split in the cooling panel are also compared with the experimental data and RELAP system code simulations. The comparisons are in reasonable agreement with the previous studies, demonstrating the ability of Flownex to simulate the RCCS behavior. It is found that the low Re case of 2,409, temperature and flow split are evenly distributed across the risers. On the contrary, there's an asymmetry trend in both temperature and flow split distributions for the high Re case of 11,524.

• Journal of Korean Vacuum Science & Technology
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• v.5 no.1
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• pp.25-32
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• 2001

Baffles have been used in cryopumps to prevent 300 K thermal radiation from reaching freely cryopanels whose temperature must be kept steadily below certain levels(4 K, 20 K or something) depending on the gas to be pumped. There are two conflicting requirements in designing a baffle such that the transmission of particles(gas molecules) should be maximized, while that of the thermal radiation(photons) minimized. The transmission probability of gas molecules or photons through chevron type baffles, influenced by the detailed geometry of blades, the reflection mode, and the absorption property of the surface, was analyzed parametrically. The effects of geometrical discrepancy between the fabricated baffle and the designed one, resulting in unexpected deterioration in the performance of the baffle, were also investigated by taking into account the gaps(or overlaps) between the baffle blades and the asymmetry in the blade arms.

• 한국벤처창업학회:학술대회논문집
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• 2022.04a
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• pp.25-30
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• 2022

Despite the importance of partnership for commercialization of innovations in startups, it is not easy for startups to persuade an established firm to collaborate on a completely novel idea. If information transfer about the innovations is too costly, startups may avoid pursuing radically new projects. Our paper examines the impact of policy signals on the novelty of the innovations pursued by startups. In the context of the Orphan Drug Act(ODA), we find that startups develop more radical therapies when policy signals help them to convince potential partners of the value of prospective therapies. While the likelihood of partnership increases, the timing of partnership is delayed in ODA-affected fields.

• Asia pacific journal of information systems
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• v.29 no.4
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• pp.731-751
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• 2019

This study examined the impact of various product photo features on the attention of potential consumers in online apparel retailers' environment. Recently, the method of apparel's product photo representation in online shopping stores has been changed a lot from the classic product photos in the early days. In order to investigate if this shift is effective in attracting consumers' attention, we examined the related theory and verified its effect through laboratory experiments. In particular, experiment data was collected and analyzed using eye tracking technology. According to the results of this study, it was shown that the product photos with asymmetry are more attractive than symmetrical photos, well emphasized object within a photo more attractive than partially emphasized, smiling faces are more attractive for customer than emotionless and sad, and photos with uncentered models focus more consumer's attention than photos with model in the center. These results are expected to help design internet shopping stores to gaze more customers' attention.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.99-101
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• 2008

At 21st century, material development concepts were changed to fulfill the environmental friendly demands. This study is to study the effect of pressurized nitrogen gas and manganese in high nitrogen austenitic stainless steel(HNS) in which N and Mn elements substitute the nickel element. 100kg HNS ingots were made by Pressurized Vacuum Induction Melting(P-VIM) and were forged according to free forging process. As forged HNS were hot and cold rolled by pilot scale rolling machine. Depending on the rolling condition, the mechanical properties of HNS were changed. The roll thrust and sheet folding showed asymmetry condition between work and drive side during cold and hot rolling. The purpose of this study are to improve workability the hot and cold rolling machine and to set the conditions for establishing the rolling process.