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11.
Chang-Yu Lu Myung-Cheol Roh Seung-Yeon Kang Seong-Whan Lee 《Pattern Analysis & Applications》2012,15(2):175-187
The amount of user created contents has been increasing rapidly and is associated with a serious copyright problem. Automatic logo detection and recognition in videos is a natural and efficient way of overcoming the copyright problem. However, logos have varying characteristics, which make logo detection and recognition very difficult. Moreover, logo transitions between two different logos exist in one video comprising several video contents. This disrupts the automatic logo detection and recognition. Therefore, in order to improve logo detection, it is necessary to take into account the logo transitions explicitly. This paper proposes an accurate logo transition detection method for recognizing logos in digital video contents. The proposed method accurately segments a video according to logo and efficiently recognizes various types of logos. The experimental results demonstrate the effectiveness of the proposed method for logo detection and video segmentation according to logo. 相似文献
12.
Ji Eun Lee Hoon Chae Park Hang Seok Choi Seung Yeon Cho Tae Young Jeong Sung Cheoul Roh 《Korean Journal of Chemical Engineering》2016,33(3):782-794
Numerical simulations were conducted using computational fluid dynamics to evaluate the effect of ventilation conditions on radon (222Rn) reduction performance in a residential building. The results indicate that at the same ventilation rate, a mechanical ventilation system is more effective in reducing indoor radon than a natural ventilation system. For the same ventilation type, the indoor radon concentration decreases as the ventilation rate increases. When the air change per hour (ACH) was 1, the indoor radon concentration was maintained at less than 100 Bq/m3. However, when the ACH was lowered to 0.01, the average indoor radon concentration in several rooms exceeded 148 Bq/m3. The angle of the inflow air was found to affect the indoor air stream and consequently the distribution of the radon concentration. Even when the ACH was 1, the radon concentrations of some areas were higher than 100 Bq/m3 for inflow air angles of 5° and 175°. 相似文献
13.
Hyun-Seog Roh Jong-San Chang Sang-Eon Park 《Korean Journal of Chemical Engineering》1999,16(3):331-337
Both powder-type and film-type mesoporous silica materials have been prepared by using a sol-gel process in highly acidic,
solvent-rich and mild conditions by solvent evaporation method. Powder mesoporous silica which has hexagonal arrays was well
synthesized within only 10 minutes, and mesoporous film was formed on the glass plate within only several seconds by supramolecular
interactions between the silicate species and surfactant-templates. In particular, the synthesis time was very short compared
with that of hydrothermal synthesis owing to the solvent evaporation. This method has some characteristics different from
the hydrothermal method such as the following. There is no precipitation because particles do not form in the solution before
solvent evaporation, bulk powder is rigid, whereas that of hydrothermal synthesis is very soft, and mesoporous materials are
synthesized in acidic condition. Solvent evaporation method for the synthesis of mesoporous materials is promising because
the method is very simple and time-saving. 相似文献
14.
15.
Dong-Hyuck Seo Tae-Seong Roh Dong-Whan Choi 《Journal of Mechanical Science and Technology》2009,23(3):677-685
A hybrid method of an artificial neural network (ANN) and a support vector machine (SVM) has been used for a health monitoring
algorithm of a gas turbine engine. The method has the advantage of reducing learning data and converging time without any
loss of estimation accuracy, because the SVM classifies the defect location and reduces the learning data range. In off-design
condition, however, the operation region of the engine becomes wide and the nonlinearity of learning data increases considerably.
Therefore, an improved hybrid method with the module system and the advanced SVM has been suggested to solve the problems.
The module system divides the whole operating region into reasonably small-sized sections, and the advanced SVM has two steps
of the classification. The proposed algorithm has been proven to reliably and effectively diagnose the simultaneous defects
of the triple components as well as the defects of the single and dual components of the gas turbine engine in off-design
condition.
This paper was recommended for publication in revised form by Associate Editor Tong Seop Kim
Tae-Seong Roh received his B.S. and M.S. degrees in Aeronautical Engineering from Seoul National University in 1984 and 1986. He then went
on to receive his Ph.D. degree from Pennsylvania State University in 1995. Dr. Roh is currently a Professor at the department
of Aerospace Engi-neering at Inha University in Incheon, Korea. His research interests are in the area of combustion instabilities,
rocket and jet propulsions, interior ballistics, and gas turbine engine defect diagnostics.
Dong-Whan Choi received his B.S. degree in Aeronautical Engineering from Seoul National University in 1974. He then went on to receive his
M.S. and Ph.D. degrees from University of Washington in 1978 and 1983. Dr. Choi served three years as a President of Korea
Aerospace Research Institute from 1999. He is currently a professor at the department of Aerospace Engineering at Inha University
in Incheon, Korea. His research interests are in the area of turbulence, jet propulsions, and gas turbine defect diagnostics. 相似文献
16.
Woojin Chung Myoungkuk Park Kwanghyun Yoo Jae Il Roh Jongsuk Choi 《Journal of Mechanical Science and Technology》2011,25(11):2895-2905
A passive multiple-trailer system provides various practical advantages for multi-functional service robots. However, motion
control is difficult because the kinematic model is highly nonlinear. The kinematic design of a trailer system was proposed
in prior research of ours. In this paper, it is shown how the backward motion of a robot with n passive trailers can be controlled.
Once the desired trajectory of the last trailer is computed, the control input of the pushing robot is obtained through the
proposed control scheme. Some experimental issues on reversing the trailer system are addressed. This paper provides an answer
to the following question: “Does the system work well even if there are sensing or modeling errors?” Although it is difficult
to obtain general analytic solutions for the above research question, a practical answer will be explored though simplified
analysis and experiments. Experimental verifications are carried out using a mobile robot with three passive trailers. The
experimental results show that backward-motion control can be successfully carried out by applying the proposed control scheme. 相似文献
17.
Feng-Jin Li Byeong-Gyu Roh Hyun-Taek Lim Ji-Soo Kim Jae-Yong Park Hong-Woo Yu Seung-Chul Park Yoon-Heung Tak Byung-Chul Ahn 《Thin solid films》2009,517(9):2941-2944
Thin silver film is widely used as the cathode in organic light-emitting diode displays and it is generally fabricated using the thermal evaporation method. But during the evaporation process, there is an inevitable outgassing problem and this creates high viscosity bubbles in melted silver. When the bubbles break, the high energy released scatters silver droplets which damage the silver surface. In this study, we were able to decrease the number of droplets from 6,171 to 278 with a degassing process of 400 °C for 6 h before proceeding with a thermal evaporation process. 相似文献
18.
WiMAX is the first cellular standard that employs OFDMA technology and provides true integrated services for both fixed and mobile broadband access. Among the many new technologies adopted in WiMAX, MIMO antenna technology plays an essential role in delivering fast, rich-content, mobile broadband service reliably over extended coverage areas. In this article we provide a survey on the state of art of MIMO technologies in current WiMAX standards with an emphasis on practical engineering considerations. Moreover, we also briefly discuss the ongoing MIMO technologies in the evolution toward the next-generation WiMAX network. 相似文献
19.
Roh Y Khuri-Yakub BT 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(3):293-298
A simple electromechanical equivalent circuit model is used to predict the behavior of capacitive micromachined ultrasonic transducers (cMUT). The equivalent circuit model of the cMUT lacks important features such as coupling to the substrate and the ability to predict crosstalk between elements of an array of transducers. To overcome these deficiencies, a finite element model of the cMUT is constructed using the commercial code ANSYS(R). Calculation results of the complex load impedance seen by single capacitor cells are presented, then followed by a calculation of the plane wave real load impedance seen by a parallel combination of many cells that are used to make a transducer. Crosstalk between 1-D array elements is found to be due to two main sources: coupling through a Stoneley wave propagating at the transducer-water interface and coupling through Lamb waves propagating in the substrate. To reduce the crosstalk level, the effect of structural variations of the substrate are investigated, which includes a change of its thickness and etched trenches or polymer walls between array elements 相似文献
20.
Roh Sungwon; Ahn Dong Hyun; Nam Jung Hyun; Yang Byung Hwan; Lee Bang Hun; Kim Yang Suk 《Canadian Metallurgical Quarterly》2006,14(1):94
Clozapine is an atypical antipsychotic agent that is more effective than the standard neuroleptics currently used for treating refractory schizophrenia. In addition, clozapine is a drug with few extrapyramidal side effects. However, clozapine is also associated with potentially serious adverse effects, such as cardiac complications as well as agranulocytosis. Clozapine-related cardiomyopathy has not been previously reported in East Asia. This report describes a 31-year-old Korean male patient with schizophrenia who developed dilated cardiomyopathy on treatment with clozapine. The removal of clozapine caused subsequent physical improvement. However, the readministration of clozapine for managing relapse of psychosis caused a recurrence of dilated cardiomyopathy in this patient. Therefore, this is the 1st report showing that the 2nd trial of clozapine caused recurrence of cardiomyopathy associated with clozapine. Thus, this report adds important support for a causal relation between clozapine and cardiac complications. In conclusion, this report attempts to raise awareness of clozapine-related cardiomyopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献