• 천문학논총
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• 제18권1호
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• pp.1-9
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• 2003

In the framework of linear perturbation theory and linear approximation of spacetime anisotropy, we investigated the formulae for the CMBR temperature anisotropy and fluctuation spectrum which have their origin in the primordial tensor perturbations of the perturbed Bianchi type I universe model. The resulting formulae were compared with those of the flat Friedmann model.

• 한국항해학회지
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• 제22권4호
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• pp.37-44
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• 1998

This paper presents a procedure for automated extraction of ridge shadows in noisy gray images. This procedure mainly consists of 1) a deformable model which is designed basing upon the knowledge about the shape of shadows and is expected to be useful in extracting ridge shadows especially located in low signal to noise ratio background, and 2) the scale space scheme which is also useful even if there is less information about the size and the positions of ridge shadows in advance. This procedure is applied to artificial images and its performance is evaluated experimentally.

• 천문학회보
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• 제35권2호
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• pp.49.2-49.2
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• 2010

In order to understand the configuration of magnetic field producing a solar penumbral microjet that was recently discovered by Hinode, we performed a magnetohydrodynamic simulation reproducing a dynamic process of how that configuration is formed in a modeled solar penumbral region. A horizontal magnetic flux tube representing a penumbral filament is placed in a stratified atmosphere containing the background magnetic field that is directed in a relatively vertical direction. Between the flux tube and the background field there forms the intermediate region in which the magnetic field has a transitional configuration, and the simulation shows that in the intermediate region magnetic reconnection occurs to produce a clear jet- like structure as suggested by observations. The result that a continuous distribution of magnetic field in three-dimensional space gives birth to the intermediate region producing a jet presents a new view about the mechanism of a penumbral microjet, compared to a simplistic view that two field lines, one of which represents a penumbral filament and the other the background field, interact together to produce a jet. We also discuss the role of the intermediate region in protecting the structure of a penumbral filament subject to microjets.

• 대한기계학회논문집B
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• 제24권6호
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• pp.845-851
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• 2000

In this paper, we show the numerical and the experimental results of two-dimensional fluid motions inside a rectangular container subjected to a background rotation added by a rotational oscillation. In the PlY experiment we apply a new algorithm, new three step search(NTSS), to the velocity calculation. In the numerical computation, the linear Ekman-pumping model was used to take the bottom friction effect into account. It was found that it well produces the experimental results at low e number.

• 패션비즈니스
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• 제22권3호
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• pp.16-29
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• 2018

The present study examines whether consumers' perception of waiting time and their behavioral intentions are influenced by the presence of background music in an online shopping environment. In particular, this study aims to explain the underlying mechanism for the effects of background music on consumers' perceived wait and behavioral intentions toward the online retailer by proposing the mediating role of emotions drawing on the Stimulus-Organism-Response (S-O-R) framework. A lab experiment was employed to test the hypotheses. A total of 102 college students were used for data analyses. Results show that the presence of music has a significant impact on participants' emotions, perceived waiting time, and approach behavior. Moreover, the findings show that pleasure and the perceived waiting time serve as mediators in the relationship between the presence of music and approach behavior. Implications of the model for theory, practice, and further research are discussed.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2009년도 추계학술대회
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• pp.1-7
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• 2009

Most industrial accidents occur when the workers' unsafe behavior and the unsafe situation of workplace take place at the same time. Although human's unsafe behavior is indispensable to work field, the evaluation scheme to detect the causes for the accident resulted from human's unsafe behavior and counterplan should be prepared to prevent and reduce accident. To do this, we first classify the specific background factors in terms of human inner factor and environment factor and then develop the AHP (Analytic Hierarchy Process) model to analyze the background factors that affect the worker's unsafe behavior. We also develop a checklist to be able to evaluate the occurrence possibility of individual worker's unsafe behavior.

• 천문학회보
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• 제41권1호
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• pp.46.3-47
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• 2016

We construct a solar eruption model with a background solar wind by performing three-dimensional zero-beta magnetohydrodynamic (MHD) simulation. The initial configuration of a magnetic field is given by nonlinear force-free field (NLFFF) reconstruction applied to a flux emergence simulation. The background solar wind is driven by upflows imposed at the top boundary. We analyzed the temporal development of the Lorentz force at the flux tube axis. Based on the results, we demonstrate that a solar eruption is caused by the imbalance between magnetic pressure gradient force and magnetic tension force. We conclude that this imbalance is produced by a weak but continuously existing solar wind above an active region.

• Archives of Plastic Surgery
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• 제50권1호
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• pp.96-100
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• 2023

The microsurgical anastomosis is integral to the success of autologous-free tissue transfer. Successful performance of this procedure relies strongly on operator dexterity, which can be made more challenging when blood and edematous fluids obscure the field of view. Workflow is impeded by intermittent irrigation and suctioning, necessitating presence of an assistant, with risk of arterial thrombosis, from vessels being drawn into suction drains. To negate these current disadvantages and minimize the barrier of entry to microvascular operations, we designed, manufactured, and patented a novel three-dimensional printed microsurgical background device with microfluidic capabilities that allow continuous suction and irrigation as well as provide platforms that enable multiangle retraction to facilitate operator autonomy. This was validated in an ex vivo model, with the device found to be superior to the current standard. We believe that this will have major applicability to the improvement of microsurgeon

• 융합신호처리학회논문지
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• 제13권1호
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• pp.44-49
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• 2012

간접접촉 심전도 측정(Indirect-Contact ECG)은 일상생활에서의 무구속 무자각 측정에 적합한 새로운 심전도 측정 방법이다. 간접접촉 심전도 측정 에 서 관측되는 큰 배경 잡음을 줄이기 위한 기초 연구로서, 본 연구에서는 간접 접촉 심전도에서 사용되는 용량성 결합 능동 전극(Capacitively coupled active electrode)의 열잡음(Thermal Noise) 모델을 구성하였다. 실험을 통해, 용량성 결합 능동 전극만의 배경 잡음의 크기가 열잡음 모델에서 예상한 수준과 거의 일치함을 확인하였다. 면으로 된 직물의 실제의 전기적 특성을 열잡음 모델에 적용하여, 면 위에서 측정된 간접접촉 심전도의 이론적 열잡음을 계산하였다. 이 연구를 통해, op-amp의 내부 잡음(intrinsic noise)은 저항에 의한 열잡음에 비해 무시할 수 있을 정도로 작음을 알 수 있었다. 그리고 열잡음의 크기와 능동 전극의 입력 저항간의 관계를 도출할 수 있게 되어, 능동 전극의 입력 저항의 최적 값 선정을 위한 향후 연구의 기반이 되었다.

• 소프트웨어공학소사이어티 논문지
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• 제29권1호
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• pp.13-21
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• 2020

CNN 모델이 이미지 분류와 객체 탐지 등 여러 분야에 활용됨에 따라, 자율주행자동차와 같이 안전필수시스템에 사용되는 CNN 모델의 성능은 신뢰할 수 있어야 한다. 이에 CNN 모델이 다양한 환경에서도 성능을 유지하는지 평가하기 위해 배경을 변경한 이미지를 생성하는 이미지 데이터 증강 도구를 개발한다. 이미지 데이터 증강 도구에 객체가 존재하는 이미지를 입력하면, 해당 이미지로부터 객체 이미지를 추출한 후 수집한 배경 이미지 내에 객체 이미지를 합성하여 새로운 이미지를 생성한다. CNN 모델 성능 평가 방법으로 개발한 도구를 사용하여 기존 테스트 이미지로부터 새로운 테스트 이미지를 생성하고, 생성한 새로운 테스트 이미지로 CNN 모델을 평가한다. 사례 연구로 Pascal VOC2007 테스트 데이터로부터 새로운 테스트 이미지를 생성하고, 새로운 테스트 이미지로 YOLOv3 모델을 평가하였다. 그 결과 기존 테스트 이미지의 mAP 보다 새로운 테스트 이미지의 mAP가 약 0.11 더 낮아지는 것을 확인하였다.