• Journal of Biosystems Engineering
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• 제39권4호
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• pp.400-404
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• 2014

Purpose: Concerns over the quantity of available freshwater for agriculture have triggered the development of technologies intended to increase efficiency of water use, especially with regard to irrigation. A new technique called fertirrigation has been developed to use the same irrigation equipment for fertilization. Methods: Since the above-mentioned technique requires care during installation and use on farms, current analysis focuses on some of its characteristics. Results: High uniformity irrigation systems provide the best distribution of fertilizers, especially when used in combination with drip irrigation or micro-aspersion. The factors purity, compatibility, acidification, salinity, and solubility should be taken into account. Conclusions: Fertirrigation provides a significant increase in productivity as it allows for highly controlled nutrient application during the entire growing season. However, it may cause serious problems if misused or overused.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.150-153
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• 2006

Micro vibration isolation, typically originated from ground, is always a prime concern for the nano-measurement instruments such as Atomic Force Microscopes. A four mount active vibration isolation system is proposed in this paper. Modeling and control of such a four mount system as analyzed. Combined active-passive isolation principle is used for vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in parallel that consists of very soft actuation system, the Voice Coil Motor. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator.

• International Journal of Fluid Machinery and Systems
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• 제1권1호
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• pp.92-100
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• 2008

The main objective of this study was to clarify the origin of the unsteady flows arising in a mixed-flow vaneless diffuser system and also the effects of physical components of the system. The testing equipment consists of a straight tube, a swirl generator, and a mixed-flow vaneless diffuser. Pressure fluctuations of the flow through the tube and diffuser were measured by using a semiconductor-type pressure transducer and analyzed by an FFT analyzer. In the experiment, the velocity ratio (axial velocity/peripheral velocity) of the internal flow, and the geometric parameters of the diffuser were varied. Two kinds of unsteady flows were measured according to the combination of the components, and the origin of each unsteady flow was clarified. The fundamental frequencies of unsteady flows arose were examined by two-dimensional small perturbation analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.311-314
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• 1997

According to the development of industrial equipment such as semiconductor manufacturing machines, optical device, and precision machine tool, a high-precision translation system with wide range has been required. This paper describes a high-precision 2-axis translation system, which consists of microstage and global stage. In order to achieve the highresolution in the long range, some engineering techniques are used. Three linear guides with flexible coupling are adopted to reduce the motor vibration in the global stage. A simple elastic hinge structure activated by five PZT is applied to reduce the angular dev~atlon. As the result of combination of microstage and global stage associated with some engineering techniques, the 2-axis translation system can measure the 200 X 200 mrn range with the nanometer accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.236-239
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• 1995

It is useful to simulate the human visual function for the purpose of image-processing. In this study, the hardware of the spatial filter with the sensitivity of lateral inhibition is realized by the combination of optical parts with electronic circuits. The diffused film with the characteristics of Gaussian type is prepared as a spatial filter. An object's image is convoluted with the spatial filter. From the difference of the convoluted images, the zero-cross position is detected at video rate. The edge of object is extracted in real-time by the use of this equipment. The resolution of edge changes with the value of the standard deviation of diffused film. In addition, it is possible to extract a directional edge selectively when the spatial filter with directional selectivity is used instead of Gaussian type of spatial filter.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1061-1064
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• 2009

The objective of this study is to find the optimal operational planning of the hybrid cooling system, which is combined by ice storage system and the absorption chiller. The optimization technique used in this study is dynamic programming. The objective function is summed cost during a day including charge and discharge periods of ice storage system and operation time of absorption chiller. Assuming that initially ice storage tank is stored fully and the cooling load is perfectly predicted for the operational planning. This method provides the most efficient and economic combination of equipment operational planning for cooling with respect to energy consumption cost.

• 한국소음진동공학회논문집
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• 제15권4호
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• pp.375-381
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• 2005

The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation were carried out to examine the characteristics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of experimental studies it has been confirmed that the existence of important frequency ranges, which were attributable to the suspension and chassis system. The tire, axle and chassis natural frequency of automobile govern the road noise. Results that material property of tire and experimental condition are parameter for shifting of tire natural frequency, which enables a designer of an automobile to foresee the influence of the various design factors on the road noise.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.138-150
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• 2001

Researchers have investigated nasal flow both numerically and experimentally for centuries. Experimental studies most have suffered from various limitations necessary to allow the measurements to be obtained with available equipment. Nasal airflow can be subdivided into two interrelated categories; nasal airflow resistance and heat and mass transfer between the air stream and the walls of the nasal cavity. In this study, thanks to a new method for model casting by a combination of Rapid prototyping and curing of clear silicone, a transparent rectangular box containing the complex nasal cavity is made for PIV experiments. The CBC PIV algorithm is used for analysis. Average and RMS distributions are obtained for inspirational and expiration nasal airflows. Comparison between western and Korean nasal air flows are appreciated. Flow fields for Korean model shows some differences from western's. Flow resistances for breathing are measured with varying flow rates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1822-1824
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• 1996

Damage and upset of control and communication equipment due to transient overvoltages which occur due primarily to internal switching surge and external lightning surge are an important problems in electromagnetic compatibility(EMC). In this paper, we analyzed operation characteristic of metal oxide varistor widely used low voltage AC line using the electromagnetic transients program(EMTP) and compare it with experimental results and also, we modeled combination generator producing $1.2/50{\mu}s$ open circuit voltage and $8/20{\mu}s$ short circuit current as a source which is critical in calculating operation characteristic. Simulation results showed that most of Transient energy consumes at MOV located in service entrance side than load side, and it showed similar to experimental results. Therefore, entrance side MOV should be selected more energy capacity than that of load side MOV.

• Journal of Yeungnam Medical Science
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• 제37권3호
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• pp.159-168
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• 2020

The demand for drug-induced sedation for magnetic resonance imaging (MRI) scans have substantially increased in response to increases in MRI utilization and growing interest in anxiety in children. Understanding the pharmacologic options for deep sedation and general anesthesia in an MRI environment is essential to achieve immobility for the successful completion of the procedure and ensure rapid and safe discharge of children undergoing ambulatory MRI. For painless diagnostic MRI, a single sedative/anesthetic agent without analgesia is safer than a combination of multiple sedatives. The traditional drugs, such as chloral hydrate, pentobarbital, midazolam, and ketamine, are still used due to the ease of administration despite low sedation success rate, prolonged recovery, and significant adverse events. Currently, dexmedetomidine, with respiratory drive preservation, and propofol, with high effectiveness and rapid recovery, are preferred for children undergoing ambulatory MRI. General anesthesia using propofol or sevoflurane can also provide predictable rapid time to readiness and scan times in infants or children with comorbidities. The selection of appropriate drugs as well as sufficient monitoring equipment are vital for effective and safe sedation and anesthesia for ambulatory pediatric MRI.