• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.373-384
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• 2002

This paper presents a robust PID controller design technique using the concept of model matching method in the frequency domain. To design the robust PID controller satisfying disturbance attenuation and robust tracking property for a reference input, first an H$\infty$ controller satisfying given performance is designed using the H$\infty$ control method. And then, the parameters(proportional, integral, and derivative gains) of the robust PID controller are determined using the model matching at frequency domain. The proposed technique is applied to a position controller design of the web. The simulation results show that the proposed robust PID controller satisfies disturbance attenuation and tracking property.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.171-176
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• 1998

The objective of this study was to re-evaluate ultrasound attenuation as an indicator of bone properties. Ultrasound attenuation(BUA), were measured in the three orthogonal directions of trabecular bone cubes, Measurements of bone mineral density(BMD) were made using quantitative computed tomography and apparent density by weighing bone specimens and measuring their volume. Ultrasonic modulus was calculated from the standard equation with apparent density and ultrasound velocity. Ultrasound attenuation at a frequency of 0.5 MHz and BUA were correlated with BMD and ultrasonic modulus in the anterior/posterior, medial/lateral, and superior/inferior directions. Analysis of correlations demonstrated that attenuation at 0.5 MHz was superior to BUA in describing both BMD and elastic modulus of trabecular bone. This result may be used to improve current ultrasound diagnostic techniques for assessing bone status.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.313-318
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• 2015

The lung opacity on radiography is influenced by various factors. The physical density of the lung and the attenuation ensured on computed tomography (CT) scans is determined by three components : lung tissue, blood, and air. Temporary right lateral recumbency may responsible for the increase of opacity on ventrodorsal projection view. Thus, our aim is to demonstrate that the effect of right lateral recumbency posture on right lung opacity using radiograph and CT scan. In this study, 62 dogs without clinical or radiologic signs of cardiopulmonary disease are selected. Thorax radiographs per 30 seconds for 2 minutes (30s, 60s, 90s, 120s) were performed for 62 dogs. After discussion of the radiographic findings of lung field by two radiologists and a student at Chungbuk national university veterinary medical center a consensus opinion was recorded. Computed tomography per a minute (1 min, 2 min) for 2 minutes were performed for 2 dogs. Mean x-ray attenuation of lung was measured quantitatively using software at two levels (aortic arch and basal level). Among 62 dogs with radiograph comparison, 9.3% of dogs showed influence by postural effect. However, all 2 dogs with computed tomography comparison, showed influence by postural effect. In conclusion, position dependent changes of lung density in CT exam are not consistent with thoracic radiograph.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.112-112
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• 2000

The aim of this paper is to design a two degree-of-freedom H$_{\infty}$ controller for lateral control of the vehicle. The object of this controller is to track the centerline of the reference lane. The controller is splited into two parts, feedback and prefilter. The feedback part is for both robust stability and disturbance attenuation, while the prefilter is for improving the robust tracking properties of closed loop system. This paper is consist of preface, background theory, dynamics of vehicle, controller design and computer simulation.ter simulation.

• Journal of Magnetics
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• v.10 no.4
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• pp.163-170
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• 2005

The RF integrated noise filters are fabricated by photolithography. The stack for the electromagnetic noise filters consists of the nano-granular ($Co_{41}Fe_{38}AI_{13}O_8$) soft magnetic film / $SiO_2$ / Cu transmission line / seed layer (Cu/Ti) / $SiO_2$-substrate. A good signal-attenuation feature along with a low signal-reflection feature is observed in the present filters. Especially in the noise filter incorporated with a $Co_{41}Fe_{38}AI_{13}O_8$ magnetic film with lateral dimensions of $2000{\mu}m$ wide, 15 mm long and $1{\mu}m$ thick, the maximum magnitude of signal attenuation reaches -55 dB, and the magnitude of signal reflection is below -10 dB in the overall frequency range. And this level of signal attenuation is much larger than that of a noise filter incorporated with a Fe magnetic film.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.4
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• pp.7-13
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• 1992

Diffraction loss occurs when the propagation path is obstructed by mountains and hills between a base station antenna and a moving vehicle antenna in mobile-radio communication. In this paper an approximate mathematical model using Fresnel-Kirchhoff diffraction theory is considered to predict propogation attenuation by natural obstacles with lateral profiles having general shapes. Field tests are conducted using helical and crossed drooping dipole antenna at 820 MHz. The theoretical analysis used in estimating the effects of hills agrees reasonably with experimental data. The results seem to be useful for estimating the level of received power, the minimum allowable input power, the optimum site of base station and consequently, planning terrestrial microwave links.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.253-260
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• 1989

The time domain methods of estimating the attenuation coefficient are generally based on the analysis of statisical properties of the reflected echoes form an attenuating medium. Hence, it is often required to have a large number of data samples in order to obtain a statistically stable estimation result. In the attenuation estimation problem, this means that many different speckle patterns are required in the spatial resolution volume of an attenLlation image. In this paper, by using the fact that the speckle pattern Is sensitive to the point spread function of the ultrasound beam, we suggest a method to generate the statiscally uncorrelated or slightly correlated data samples in a given region by rotating a linear transducer and carrying out lateral scans for all rotating angles. This technique is applied to the entropy method for attenuation estimation proposed recently by the authors where the performance is verified by experiments using a tissue equivalent phantom.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.3
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• pp.149-154
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• 2002

The blood pressure (BP) is regulated by the nervous system and humoral factors, such as renin- angiotensin system, vasopressin and others. In the present study, we examined the central effects of glutamate and GABA on the cardiovascular regulation by injection of these substances into the lateral ventricle and also investigated the relationship between these central effects and the action of angiotensin II (Ang). Male Sprague Dawley rats, $350{\sim}400$ g, were anesthetized with urethane and instrumented with an arterial catheter for direct measurement of BP and heart rate (HR), and an guide cannula in the lateral ventricle for drug injection. A glass microelectode was inserted into the rostral ventrolateral medulla (RVLM) for recording single unit spikes. Barosensitive neurons were identified by changes of single unit spikes in RVLM following intravenous injection of nitroprusside and phenylephrine. The effects of GABA and glutamate injected into the lateral ventricle were studied in single neuronal activity of the RVLM in addition to changes in BP and heart rate, and compared the results before and after treatment with intravenous losartan, nonpeptide Ang II-type 1 receptor antagonist (1 mg/100 g BW). Intracerebroventricular administration of GABA decreased systolic blood pressure (SBP) and HR, but increased the firing rates in the RVLM. However, intracerebroventricular glutamate injection produced effects opposite to GABA. After pretreatment of intravenous losartan, the central effects of GABA on BP and firing rate in the RVLM were significantly attenuated and that of glutamate showed a tendency of attenuation. These results suggested that central GABA and glutamate regulated BP and firing rates in RVLM were inversely related to BP change. The central effects of GABA or glutamate on the autonomic nervous function were modulated by humoral factor, Ang II, by maintaining BP.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1033-1037
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• 2007

The final purpose of this study is to develop noise abatement procedures for minimizing the environmental impacts caused by aircraft noise in the vicinity of Gimpo Int'l Airport, and to establish appropriate noise limits and monitoring system. The results of study was suggests for more detail the crucial factors which one is reference noise level, $L_{MAX}=88dB(A)$ at 6.5km after take-off, and second one is to installation the additional three(3) noise monitoring system on both side of runway.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.874-880
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• 2007

The final purpose of this study is to develop noise abatement procedures for minimizing the environmental impacts caused by aircraft noise in the vicinity of Gimpo Int'l Airport, and to establish appropriate noise limits and monitoring system. The results of study was suggests for more detail the crucial factors which one is reference noise level, $L_{MAX}=88 dB(A)$ at 6.5 km after take-off, and second one is to installation the additional three(3) noise monitoring system on both side of runway.