• 대한기계학회논문집B
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• 제37권7호
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• pp.695-701
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• 2013

본 논문은 비이온의 계면 활성제에 의해 증발하는 물방울의 열모세관 유동(마랑고니 유동)이 억제되는 것을 실험적으로 검증한다. 물방울이 소수성 표면 위에서 증발할 때, 액적 내부의 마랑고니 유동을 관찰하였고, 계면 활성제 농도에 따라 이 유동이 억제되는 것을 조사하였다. 초기 계면 활성제 농도가 증가하면, 마랑고니 유동의 속도와 수명이 감소한다. 이 결과는 계면 활성제에 의해 액적 계면에서 점착 경계 조건이 성립됨을 보여주는데, 이것은 계면 점착 현상과 관련된 기존의 모델에 기초하여 설명되었다. 또한 액적의 초기 계면 활성제 농도가 임계 농도 이하일 때, 증발 초기 접촉선 비고정 현상을 발견했는데, 이것은 마랑고니 유동이 접촉각의 이력 현상을 감소시키기 때문이다.

• 한국화재소방학회논문지
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• 제21권4호
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• pp.44-51
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• 2007

우리나라 대부분의 문화재인 사찰은 목조 건축물로 가연성이 높고 도심과 떨어진 산속에 있어 화재 진화에도 소방력의 접근성이 용이하지 않아 초기 진화가 어렵다. 또한 장기 지속적인 화원으로부터 문화재 보호를 위한 수원의 확보 및 자체 소방시설도 한계가 있다. 따라서 본 연구에서는 산불로 인한 화재의 초기 진화 및 장기 지속적인 화원으로부터 문화재를 보호하고자 기존의 수계설비보다 피해를 최소화 할 수 있는 미분무수 설비를 적용하여 우리나라 문화재의 지형적 위치를 고려한 가연물의 발화에너지를 제거하는 방식의 소방시설과 차단벽을 활용한 방식의 소방시설을 제안하였다.

• 대한임상검사과학회지
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• 제37권2호
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• pp.96-101
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• 2005

Status epilepticus is a medical emergency, so that rapid and vigorous treatment is required to prevent neuronal damage and systemic complication. Status epilepticus is generally defined as a continuous or intermittent seizure or an unconscious condition after the onset of seizure, lasting for 30 minutes or more. We report here the outcome of status epilepticus. We retrospectively reviewed medical record of 15 patients who were diagnosed with status epilepticus at the Asan Medical Center from January 2003 to February 2004. This outcome was evaluated considering various factors such as age of patients, history of seizures, neurologic impairment, etiology, mortality, return to baseline and initial electroencephalogram (EEG) findings. The range of age was between 1 to 79 years old and the longest duration of treatment was 118 days. Most patients were treated by using pentobarbital, midazolam, phenobarbital and other antiepileptic drugs. The overall mortality was 5 (33%) out of 15 patients. The mortality was related to etiology, underlying other medical conditions and initial EEG findings. 5 (55%) out of the 9 patients with acute etiology, 5 (71%) out of the 7 patients with a multifocal or burst-suppression EEG activity, and 3 (60%) out of the 5 patients with other medical disease were related to mortality. This data demonstrate high mortality due to status epilepticus. Mortality is related to etiology, other medical conditions and abnormalities on the initial EEG.

• The Plant Pathology Journal
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• 제24권3호
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• pp.352-356
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• 2008

Root discs of 4-year-old ginseng, Panax ginseng C. A. Meyer, were inoculated with the higher($10^8$ colonyforming units(CFU)/ml) and lower($10^6\;or\;10^5$ CFU/ml) initial inoculum levels of a plant-growth promoting rhizobacterium(PGPR), Paenibacillus polymyxa GBR-1 to examine rot symptom development and bacterial population changes on the root discs. At the higher inoculum level, brown rot symptoms developed and expanded on the whole root discs in which the bacterial population increased continuously up to 4 days after inoculation. In light and electron microscopy, ginseng root cells on the inoculation sites were extensively decayed, which were characterized by dissolved cell walls and destructed cytoplasmic contents. However, no rot symptoms were developed and the bacterial population increased only during the initial two days of inoculation at the lower inoculum level($10^6$ CFU/ml) of P. polymyxa GBR-1. At the lower inoculum level($10^5$ CFU/ml), boundary layers with parallel periclinal cell divisions, structurally similar to wound periderm, were formed internal to the inoculation sites, beneath which the cells were intact containing numerous normal-looking starch granules and no disorganized cell organelles, suggesting that these structural features may be related to the suppression of symptom development, a histological defense mechanism.

• 제어로봇시스템학회논문지
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• 제21권2호
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• pp.145-149
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• 2015

This paper introduces a sway suppression control for container cranes with unknown payloads and sway rates. With no priori knowledge concerning the magnitude of payload mass and sway rate, the proposed control maintains superior sway suppressing and trolley positioning against external disturbances. The proposed scheme combines a second order sliding mode control and an adaptive control to cope with unknown payloads. A second order sliding mode control without feedback of the sway rate is first designed, which is based on a class of feedback linearization methods for stabilization of the under-actuated sway dynamics of the container. Under applicable restrictions of the magnitude of payload inertia and sway rate, a linear regression model is obtained, and an adaptive control with a payload estimator is then designed, which is based on Lyapunov stability methods for the fast attenuation of trolley oscillations in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown in the existence of initial sway and external wind disturbances.

• 한국생산제조학회지
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• 제21권6호
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• pp.878-884
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• 2012

In this paper, we consider the sway suppression control problem for container cranes with the frictions between the trolley and the rail. If the friction effects in the system can be modelled, there is an improved potential to design controllers that can cancel the effects. The proposed control improves the trolley positioning and sway suppressing against various frictions. The proposed synthesis combines a variable structure control and the adaptive control to cope with various frictions including the unknown constants. First, the variable structure control with the simple switching action is designed, which is based on a class of feedback lineariztion methods for the fast stabilization of the under-actuated sway dynamics of container. Second, the adaptive control with a parameter estimation is designed, which is based on Lyapunov stability methods for suppressing the oscillation of the trolley travelling, especially due to Coulomb friction in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown under initial sway, external wind disturbances, and various frictions.

• 대한안전경영과학회지
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• 제18권3호
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• pp.1-8
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• 2016

The definition of an apartment is a building more than 5 stories high and which is the standard law. Currently, the number of apartments is increasing much faster than detached houses. Owning an apartment is a normal trend these days. However, the increasing number of apartments has been increasing the number of apartment fires which also has been making social problems. Therefore, this study was conducted for the fire extinguisher among other fire facilities because it is important for initial fire suppression. The research subject is on the fire extinguisher that is in the underground parking lot of 40 apartment complexes which are more than 10 stories. Survey and analysis were conducted for 80 fire extinguishers. There are two fire extinguishers for each apartment. The result of this study is that all installed fire extinguishers are ABC dry chemical type, 92% of them is 3.3kg and that meet the legal height(less than 1.5m). However, the condition such as appearance, inspection, manufactured year, appearance of signs, material of signs, size of signs, etc. was insufficiency. So improvement of law and system that are fire facility construction, maintenance implementation and additional designation of type approval about sign will be needed in my opinion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1795-1811
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• 2019

In order to achieve rapid and accurate detection of vehicle objects in complex traffic conditions, we propose a novel vehicle detection method. Firstly, more contextual and small-object vehicle information can be obtained by our Joint Feature Network (JFN). Secondly, our Evolved Region Proposal Network (EPRN) generates initial anchor boxes by adding an improved version of the region proposal network in this network, and at the same time filters out a large number of false vehicle boxes by soft-Non Maximum Suppression (NMS). Then, our Mask Network (MaskN) generates an example that includes the vehicle occlusion, the generator and discriminator can learn from each other in order to further improve the vehicle object detection capability. Finally, these candidate vehicle detection boxes are optimized to obtain the final vehicle detection boxes by the Fine-Tuning Network(FTN). Through the evaluation experiment on the DETRAC benchmark dataset, we find that in terms of mAP, our method exceeds Faster-RCNN by 11.15%, YOLO by 11.88%, and EB by 1.64%. Besides, our algorithm also has achieved top2 comaring with MS-CNN, YOLO-v3, RefineNet, RetinaNet, Faster-rcnn, DSSD and YOLO-v2 of vehicle category in KITTI dataset.

• 한국정밀공학회지
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• 제11권1호
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• pp.54-62
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• 1994

This paper presents active control methodologies to suppress structural deflections of a composite beam using a distributed piezoelectric-film actuator and sensor. Three types of different controllers are employed to achieve vibration suppression. The controllers are established depending upon the information on the velocity components of the structrue and on the deflection magnitudes as well. They are constant-amplitude controller(CAC), constant-gain mcontroller(CGC), and constant-amplitude-gain controller(CAGC). For the minimization of the residual vibration (chattering in a settled phase), which is the practical shortcoming of the conventional CAC dur to time delay phenomenon of the hardware system, a new control algoritym CAGCis designed by selecting switching constants in an optimal manner with respect to the initial tip deflection and the applied voltage. The experimental investigations of the transient and forced vibration control for the first vibrational mode are undertaken in order to compare the suppression efficiency of each control algorithm. Moreover, simultaneous controllability of various vibrational modes through the proposed scheme is also experimentally verified by pressenting both the transfer function and the phase.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3754-3767
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• 2023

Turbulent jet discharges in subcooled water pools are essential for safety systems in nuclear power plants, specifically in the pressure suppression pool of boiling water reactors and In-containment Refueling Water Storage Tank of advanced pressurized water reactors. The gas and liquid flow in these systems is investigated using multiphase flow analysis. This field has been extensively examined using a combination of experiments, theoretical models, and Computational Fluid Dynamics (CFD) simulations. ANSYS CFX offers two approaches to model multiphase flow behavior. The non-homogeneous Eulerian-Eulerian Model has been used in this work; it computes global information and is more convenient to study interpenetrated fluids. This study utilized the Large Eddy Simulation Model as the turbulence model, as it is better suited for non-stationary and buoyant flows. The CFD results of this study were validated with experimental data and theoretical results previously obtained. The figures of merit dimensionless penetration length and the dimensionless buoyancy length show good agreement with the experimental measurements. Correlations for these variables were obtained as a function of dimensionless numbers to give generality using only initial boundary conditions. CFD numerical model developed in this research has the capability to simulate the behavior of non-condensable gases discharged in water.