• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.522-531
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• 2002

In order to study the thermal-hydraulic behavior of the cable-in-conduit-conductor (CICC), a numerical model has been developed. In the model, the high heat transfer approximation between superconducting strands and supercritical helium is adopted. The strong coupling of heat transfer at the front of normal zone generates a contact discontinuity in temperature and density. In order to obtain the converged numerical solutions, a moving mesh method is used to capture the contact discontinuity in the short front region of the normal zone. The coupled equation is solved using the finite element method with the artificial viscosity term. Details of the numerical implementation are discussed and the validation of the code is performed for comparison of the results with thse of GANDALF and QSAIT.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.12-18
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• 2020

In semiconductor manufacturing, defect detection is critical to maintain high yield. Currently, computer vision systems used in semiconductor photo lithography still have adopt to digital image processing algorithm, which often occur inspection faults due to sensitivity to external environment. Thus, we intend to handle this problem by means of using Mask R-CNN instead of digital image processing algorithm. Additionally, Mask R-CNN can be trained with image dataset pre-processed by means of the specific designed digital image filter to extract the enhanced feature map of Convolutional Neural Network (CNN). Our approach converged advantage of digital image processing and instance segmentation with deep learning yields more efficient semiconductor photo lithography inspection system than conventional system.

• 대한전자공학회논문지TC
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• 제47권9호
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• pp.14-18
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• 2010

이중의 제한조건을 사용하는 선형제한 최소분산 (Linear Constraint Minimum Variance LCMV) 빔형성 (Beamforming) 방식에서 가중치 벡터가 갱신 될수록 최적 가중치 벡터에 수렴하기 위한 수렴조건을 분석하였다. 또한 유도된 조건하에서 가중치 벡터가 수렴함을 전산실험을 통하여 보였다.

• 한국환경과학회지
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• 제11권4호
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• pp.289-295
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• 2002

We would like to investigate the strong wind phenomenon effecting to the onset of a sea breeze. It is general the fact that the onset time of a sea breeze is mainly affected according to the distance from the coastline but we find the reversal fact. The onset time at Suyoung is faster than that at Haeundae in spite of the observation site of Suyoung is 5 m and that of Haeundae is 1 km away from the coastline. This is the reason that the nighttime air is converged the lower area by surface cooling and then it is strongly drained onto the lowest area, Suyoung river until the sunrise. it is proved by observation data at Suyoung and Haeundae.

• 한국세라믹학회지
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• 제56권3호
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• pp.325-330
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• 2019

Band convergence is known to be effective in improving thermoelectric performance by increasing the Seebeck coefficient without significantly reducing electrical conductivity. Decoupling of the Seebeck coefficient and electrical conductivity in converged bands is the key requirement. Yet, the degree of decoupling depends on the band parameters of the converging bands. Herein, we report theoretical transport properties of two valence bands as their energy difference changes from 0.25 eV to 0 eV. In order to demonstrate the effect of band parameters in transport, we first conducted calculations for the case where the two bands have the same parameters. Then, we conducted the same calculation by doubling the density-of-states effective mass of one valence band. Given that there are two bands, each band's effective mass was doubled one at a time while the other band's effective mass remained constant. We found that the decoupling was strongest when the bands participating in convergence had the same band parameters.

• Journal of information and communication convergence engineering
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• 제11권1호
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• pp.17-23
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• 2013

Cloud computing is a currently developing revolution in information technology that is disturbing the way that individuals and corporate entities operate while enabling new distributed services that have not existed before. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services. Security is often said to be a major concern of users considering migration to cloud computing. This article examines some of these security concerns and surveys recent research efforts in cryptography to provide new technical mechanisms suitable for the new scenarios of cloud computing. We consider techniques such as homomorphic encryption, searchable encryption, proofs of storage, and proofs of location. These techniques allow cloud computing users to benefit from cloud server processing capabilities while keeping their data encrypted; and to check independently the integrity and location of their data. Overall we are interested in how users may be able to maintain and verify their own security without having to rely on the trust of the cloud provider.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.169-180
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• 2019

In this study, a batch least square estimator that utilizes optical observation data is developed and utilized to determine geostationary orbits (GEO). Through numerical simulations, the effects of error sources, such as clock errors, measurement noise, and the a priori state error, are analyzed. The actual optical tracking data of a GEO satellite, the Communication, Ocean and Meteorological Satellite (COMS), provided by the optical wide-field patrol network (OWL-Net) is used with the developed batch filter for orbit determination. The accuracy of the determined orbit is evaluated by comparison with two-line elements (TLE) and confirmed as proper for the continuous monitoring of GEO objects. Also, the measurement residuals are converged to several arcseconds, corresponding to the OWL-Net performance. Based on these analyses, it is verified that the independent operation of electro-optic space surveillance systems is possible, and the ephemerides of space objects can be obtained.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 추계학술발표대회
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• pp.109-112
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• 2020

본 논문은 기업의 중요 정보를 내부에 저장하면서도 스토리지, 컴퓨팅 및 네트워크를 단일 시스템으로 통합한 HCI(Hyper-Converged Infrastructure) 기반의 On-premises 가상화 인프라를 기업에 도입했을 때의 효과를 검증한다. 150여 대의 물리 서버를 운영하는 기업에서 신규 시스템에 대해서 HCI 가상화 기반의 인프라를 도입하여 물리 서버 대비 약 35%의 구축비용을 절감하고, 기본 사용 연수인 5년간의 유지보수 비용은 약 59%의 절감효과를 예상할 수 있었다. 이를 통해 HCI 가상화 기술을 통해 정보기술이 기업 비즈니스 성패에 큰 영향을 주는 4차산업 혁명 시대에 기업의 총 IT 소유비용(TCO)을 절감할 수 있음은 물론, 빠른 비즈니스 변화에 유연하게 대응할 수 있는 인프라를 구성할 수 있음을 시사했다. 또한 가상화로 전환을 망설이는 기업에는 실질적인 효과를 제시할 수 있을 것이다.

• 대한간호학회지
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• 제48권5호
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• pp.554-564
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• 2018

Purpose: This study aimed to construct a management model for patient transfer in a multilevel healthcare system and to predict the effect of counseling with nurses on the patient transfer process. Methods: Data were collected from the electronic medical records of 20,400 patients using the referral system in a tertiary hospital in Seoul from May 2015 to April 2017. The data were analyzed using system dynamics methodology. Results: The rates of patients who were referred to a tertiary hospital, continued treatment, and were terminated treatment at a tertiary hospital were affected by the management fee and nursing staffing in a referral center that provided patient transfer counseling. Nursing staffing in a referral center had direct influence on the range of increase or decrease in the rates, whereas the management fee had direct influence on time. They were nonlinear relations that converged the value within a certain period. Conclusion: The management fee and nursing staffing in a referral center affect patient transfer counseling, and can improve the patient transfer process. Our findings suggest that nurses play an important role in ensuring smooth transitions between clinics and hospitals.

• ETRI Journal
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• 제40권6호
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• pp.745-758
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• 2018

A wide range of studies in various disciplines has focused on the Internet of Things (IoT) and cyber-physical systems (CPS). However, it is necessary to summarize the current status and to establish future directions because each study has its own individual goals independent of the completion of all IoT applications. The absence of a comprehensive understanding of IoT and CPS has disrupted an efficient resource allocation. To assess changes in the knowledge structure and emerging technologies, this study explores the dynamic research trends in IoT by analyzing bibliographic data. We retrieved 54,237 keywords in 12,600 IoT studies from the Scopus database, and conducted keyword frequency, co-occurrence, and growth-rate analyses. The analysis results reveal how IoT technologies have been developed and how they are connected to each other. We also show that such technologies have diverged and converged simultaneously, and that the emerging keywords of trust, smart home, cloud, authentication, context-aware, and big data have been extracted. We also unveil that the CPS is directly involved in network, security, management, cloud, big data, system, industry, architecture, and the Internet.