• Journal of radiological science and technology
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• v.40 no.4
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• pp.595-603
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• 2017

The study is to produced a brain phantom simulating corpus striatum, which can evaluate the progression of parkinson's disease, to investigate possibility of reducing the brain exposure dose to CT while maintaining optimal image quality during PET-CT examinations. CT scans were performed by varying tube voltage (100, 120 kVp) and tube current (80, 140, 200 mAs) with $^{18}F$ FP-CIT injected into the phantom's hot sphere and background (radioactivity ratio 3:1)(reference condition; 120 kVp, 140 mAs). Estimated effective dose was calculated by using conversion factor according to each condition, and image quality was evaluated by setting SNR and CRChot image evaluation factors. Experimental results showed that the predicted effective dose below the CT imaging reference condition was reduced by at least 10% and by up to 60%, and the predicted effective dose beyond the reference condition was increased by 40%. In addition, there was no significant difference between SNR and CRChot of PET images, and it was confirmed that brain dose decreased with decrease of tube voltage and tube current. At the same time, there was no significant change in the quality of the image in terms of SNR and CRChot despite the change in scan conditions. This fact suggests that the quality of the images acquired under the existing dose conditions can be obtained even at low dose conditions and it is expected that it will be possible to use the brain PET-CT scan as a basic data for the research on reduction of dose and improvement of image quality.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1347-1353
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• 2008

Pulse condition is the essential division for conducting pulse diagnosis which is one of the most fundamental and important diagnostics in traditional Korean/Chinese medicine. We studied the pulse condition referred to classics of traditional medicine for a full understanding in present time and come to a conclusion like below. The reference to pulse condition was concluded to 'twenty four pulse conditions' which is the fundamental conception generally accepted in present age since it had first mentioned in "Huangdi Neijing" and after it had passed through "Nanjing", "pulse pattern identification-chapter of normal pulse"of Zhang Zhongjing and reached "Maijing"of Wang Shuhe. Although medical partitioners had different views to some extent about pulse condition, there were no significant differences in the main theoretical frame. Even though there had been a diversity of opinions on the classification of pulse-condition between various medical practitioners, the method of Dae-dae and the method of systematic endeavored by Zhou Xueting and Zhou Xuehai who were medical scholars in the Ch'ing dynasty have been a criterion for the classification of pulse-condition up to date. We were able to recognize that the change of pulse condition caused by pathological situation should be compared to physiological pulse condition for detecting the deficiency and excess by researching the analyzing methods of pulse condition mentioned in the "Lingshu", and the book of Hua Shou and Zhou Xuehai). To sum up, first normal pulse which is the physiological pulse condition should be a standard for detecting physiological pulse condition. Secondly, Zhou Xueting insisted that relaxed pulse should be a standard pulse condition for detecting normal pulse.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.162-169
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• 2016

The agrometeorological reference index means 'the agrometeorological damage possibility' or the possibility of the normal year climate condition to damage the crop cultivation in a certain region. It is a reference used to compare the cultivation risk of a crop by region. The global climate warming is expected to increase the winter temperature. At the same time, the frequency of extreme weather events will also increase. Therefore, people pay attention to the potential of low temperature-induced damages (e.g., frost damage and injury) to fruit trees under the future climate condition. However, simple damage projection based on climate conditions does not help the climate change adaptation in the practical aspect because the climate change affects the phenology of fruit trees as well. This study predicted the phenology of the pear, peach, and apple trees by using the climate change scenarios of major regions. Furthermore, low temperature induced agrometeorological reference indices were calculated based on the effects of temperature on each plant growth stage to predict the damage possibility. It was predicted that the breaking rest would delay more in the future while the bud-burst date and flowering date will be earlier. In Daegu, Jeonju, and Mokpo, the breaking rest delayed more as time passed. The bud-burst date and flowering date of Seoul and Incheon regions were later than other regions. Seoul and Incheon showed a similar pattern, while Daegu and Jeonju revealed a similar pattern. Busan and Mokpo also showed a similar pattern. All regions were safe from the frost damage during the dormancy period. However, plants were vulnerable to frost damage between the breaking rest and the bud-burst period. Regions showed different frost damage patterns between the bud-burst period and the flowering period. During the bud-burst and flowering period, the risk level decreased in general, although the risk of some areas tended to increase.

• Smart Structures and Systems
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• v.20 no.5
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• pp.549-562
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• 2017

The US railroad network carries 40% of the nation's total freight. Railroad bridges are the most critical part of the network infrastructure and, therefore, must be properly maintained for the operational safety. Railroad managers inspect bridges by measuring displacements under train crossing events to assess their structural condition and prioritize bridge management and safety decisions accordingly. The displacement of a railroad bridge under train crossings is one parameter of interest to railroad bridge owners, as it quantifies a bridge's ability to perform safely and addresses its serviceability. Railroad bridges with poor track conditions will have amplified displacements under heavy loads due to impacts between the wheels and rail joints. Under these circumstances, vehicle-track-bridge interactions could cause excessive bridge displacements, and hence, unsafe train crossings. If displacements during train crossings could be measured objectively, owners could repair or replace less safe bridges first. However, data on bridge displacements is difficult to collect in the field as a fixed point of reference is required for measurement. Accelerations can be used to estimate dynamic displacements, but to date, the pseudo-static displacements cannot be measured using reference-free sensors. This study proposes a method to estimate total transverse displacements of a railroad bridge under live train loads using acceleration and tilt data at the top of the exterior pile bent of a standard timber trestle, where train derailment due to excessive lateral movement is the main concern. Researchers used real bridge transverse displacement data under train traffic from varying bridge serviceability levels. This study explores the design of a new bridge deck-pier experimental model that simulates the vibrations of railroad bridges under traffic using a shake table for the input of train crossing data collected from the field into a laboratory model of a standard timber railroad pile bent. Reference-free sensors measured both the inclination angle and accelerations of the pile cap. Various readings are used to estimate the total displacements of the bridge using data filtering. The estimated displacements are then compared to the true responses of the model measured with displacement sensors. An average peak error of 10% and a root mean square error average of 5% resulted, concluding that this method can cost-effectively measure the total displacement of railroad bridges without a fixed reference.

• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.99-105
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• 1999

In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers a robust stability of this 2DOF servosystem with nonlinear type uncertainty in the system, and a robust stability condition for the servosystem is introduced. This result guarantees that if the plant uncertainty is in the permissible set defined by the condition, gain tuning can be carried out to suppress the influence of the plant uncertainties and disturbance inputs.

• Language and Information
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• v.8 no.2
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• pp.131-147
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• 2004

the two Korean causal conjunctive suffixes, -nula(ko) and -nun palamey, based on corpus linguistic analysis. Many of the linguistic accounts available, both in pedagogical reference and in the literature on linguistics, provide incomplete analyses of these suffixes, based on fabricated linguistic data. Using naturally occurring, real linguistic data, this paper examines the syntactic and semantic structures of the two causal suffixes through a consideration of three areas of corpus linguistic analysis: token frequencies, collocations, and semantic prosody. An analysis based on concordance data reveals that the two causal connectives, -nula(ko) and -nun palamey, have more differences than similarities in terms of syntactic and semantic constraints. The idiosyncratic structures of the two suffixes are discussed in terms of same subject condition, verb selection, same agent condition, synchronicity condition, and negative semantic prosody.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.79-89
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• 1998

In determining optimal cutting condition for face milling operation, tool wear is an important factor. For the purpose of establishing the relationship between various machining factors and tool wear, cutting tests have been performed. As a result, hardness and chemical composition of workpiece material, chemical composition and grain size of cutting tool and cutting speed have been selected as machining factors. In addition, relationship between feed rate and workpiece hardness has been observed. Prior to utilizing cutting conditions recommended by ‘Machining Data Handbook(MDH)’ as a knowledge base, an analysis for the validity of the MDH has been provided. Based on this analysis, tool life criteria applied by MDH has been modified. Finally, using MDH recommended data for neural network trainning, the results from the trained neural network for optimal cutting condition for some given workpiece and cutting tool can be used as reference cutting conditions.

• Corrosion Science and Technology
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• v.7 no.1
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• pp.61-67
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• 2008

In this paper, electrochemical and microstructural characteristics of nickel-plated Alloy 600 were investigated in order to identify the performance of electroless Ni-plating on Alloy 600 in high-temperature aqueous condition with the comparison of electrolytic nickel-plating. For high temperature corrosion test of nickel-plated Alloy 600, specimens were exposed for 770 hours to typical PWR primary water condition. During the test, open circuit potentials (OCP's) of all specimens were measured using a reference electrode. Also, resistance to flow accelerated corrosion (FAC) test was examined in order to check the durability of plated layers in high-velocity flow environment at high temperature. After exposures to high flow rate aqueous condition, the integrity of surfaces was confirmed by using both scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). For the field application, a remote process for electroless nickel-plating was demonstrated using a plate specimen with narrow gap on a laboratory scale. Finally, a practical seal design was suggested for more convenient application.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.627-638
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• 1999

In this paper, the system with an artificial intelligent that is able itself to adjust the perimeter condition of the plant is presented. The proposed intelligent system is composed of two learning vector quantization(LVQ) networks, which are used mostly in the field of the pattern recognition and signal processing. From the external condition of the plant, the first LVQ network recognizes the pattern of the sensed signal and the second LVQ network judges synthetically user's characteristics and performs learning. The controller controls the plant using the reference value, which is the output value of the synthetic judgement part. In order to verify the usefulness of the proposed method, we simulated the two LVQs are implemented for the artificial intelligent illuminator as well as being carried out computer simulations. We implemented the proposed artificial intelligent illuminator and perform the experiment.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.128-129
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• 2012

This paper proposed the wind turbine simulator for comparative study of the MPPT controls. The development of this wind turbine simulator is based on the torque controlled induction motor. The torque reference is obtained from a mathematical model of wind turbine whereas the inputs are rotor speed, wind speed and fixed-value of pitch angle. By using this wind turbine simulator, the real wind is not needed. Wind speed information can be stored and regenerated anytime. Hence it is possible to apply the same wind speed condition to different MPPT controls. With the same wind speed condition, it can fairly compare the advantages and disadvantages of the MPPT controls. The proposed wind turbine simulator is verified through PSIM simulation.