• 대한치과보철학회:학술대회논문집
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• 2000.04a
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• pp.43-43
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• 2000

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.3-9
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• 1998

This paper presents soil-gas surveying technique to delineate an area contaminated with volatile organic compounds, which are common solvents and constituents of gasoline. The sampling method of soil-gas surveying is 1) grab sampling, which actively takes sample using a pump, or 2) passive sampling, which takes sample through diffusion in a trap filled with absorbent. The grab sampling shows the level of contamination at a certain location at a certain time, while the passive sampling shows the change in the contamination at a certain location. The analysis of soil gas can be performed with 1) a small portable detectors such as PID (photoionization detector) or FID (flame-ionization detector) to measure the total hydrocarbon in the soil gas, 2) a gas detector tube, which is filled with indicator reagents and changes its color with concentrations of the gas of interest, or 3) a portable GC (gas chromatograph), which can analyze different compounds simultaneously. The soil-gas surveying technique is a much less expensive method to investigate area contaminated volatile organic compounds and thus can be used as a screening tool to identify an area, which needs to be further investigated.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.2
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• pp.75-81
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• 2018

Background: The purpose of this study was to investigate the effect of various relaxation techniques on various dysfunction problems caused by shortening of the sagittal muscles. Method: The subjects were 44(18 males, 26 females). The subjects were composed of 3 groups. The experimental group consisted of 14 patients with proprioceptive neuromuscular facilitation stretching (PNF) technique, control group A 15 patients with self myofacial release (SMR) ball exercise, and control group B with 15 patients with Sling exercise. After 3 weeks of relaxation on the hamstring muscle, the length of the hamstring muscle before and after the intervention was compared. Results: The results of relaxation exercise of the snake muscles applied to passive PNF group, SMR ball group, and Sling relaxation group are as follows. 1. In the passive PNF group, the muscle length of the hamstring muscle was significantly increased after the intervention. 2. The muscle length of the hamstring muscle was significantly increased after the intervention in the SMR ball group. 3. Sling relaxation group significantly increased the muscle length of the hamstring muscle after sling exercise intervention. 4. Passive PNF group showed the greatest change in muscle length before and after intervention than SMR ball group and Sling relaxation group. Conclusion: Passive PNF relaxation therapy, SMR ball relaxation therapy, and Sling relaxation therapy applied to the hamstring muscle were effective in increasing muscle length of the hamstring muscle. PNF relaxation therapy showed the most significant effect after 3 weeks intervention.

• Journal of Korean Physical Therapy Science
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• v.26 no.2
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• pp.38-45
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• 2019

Purpose: This study purpose to comparison the effects of passive scapular alignment exercise and hold & relaxation technique on craniovertebral angle (C1~C7) with forward head posture due to using variety bag and using computer in healthy subjects. Design: Randomized Controlled Trial. Methods: 22 subjects were divide into two groups: PSAEx group and H/R group two groups. After exercise, the CVA were measured using C7 and tragus. Collected data were statistically analyzed by SPSS 20.2 Results: There were significant differences pre and post the exercise. Conclusion: PSAEx and H/R technique was effective to correct a abnormal CVA posture. The result of this study may helpful as basic data for orthopedic physical therapy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.284-290
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• 2012

This paper addresses a new passive target tracking problem using the range differences measured by cooperative UAVs. In order to solve the range difference based passive target tracking problem within the framework of linear robust state estimation, the uncertain linear measurement model which contains the stochastic parameter uncertainty is derived by using the noisy range difference measurements. To cope with the performance degradation due to the stochastic parameter uncertainty, the recently developed non-conservative robust Kalman filtering technique [1] is applied. For the cruciform formation flying UAVs, the relationship between the target tracking performance and the measurement errors is quantitatively analyzed. The proposed filter has practical advantages over the classical nonlinear filters because, for its recursive linear structure, it can provide satisfactory convergence properties and is suitable for real-time multiple UAVs applications. Through the simulations, the usefulness of the proposed method is demonstrated.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.98-103
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• 2001

In case that electronic ballast employing a valley-fill passive power factor correction (PFC) circuit is used for feeding fluorescent lamps, a new method to reduce crest factor of the lamp current is studied in this paper. In order to reduce crest factor to lower value, a pulse frequency modulation technique based on the waveform of the dc-link voltage which is predetermined by the passive PFC circuit, is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed.

• Smart Structures and Systems
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• v.21 no.1
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• pp.99-111
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• 2018

Wind induced large bending oscillation amplitudes in tall and slender telecommunication steel towers may lead to precocious fatigue cracks and consequent risk of collapse of these structures, many of them installed in rural areas alongside highways and in highly populated urban areas. Varying stress amplitudes at hot spots may be attenuated by means of passive control mechanical devices installed in the tower. This paper gives an account of both mathematical-numerical model and the technique applied to design and evaluate the performance of a double controller installed in existing towers which is composed by a nonlinear pendulum and a novel type of passive controller described herein as a planar motion disk mounted on shear springs. Results of experimental measurements carried out on two slender tubular steel towers under wind action demonstrate the efficiency of the double controllers in attenuating the towers bending oscillation amplitudes and consequent stress amplitudes extending the towers fatigue life.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.466-471
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• 2012

In this paper, we consider the problem of a robust passive filtering with low-order for discrete-time singular systems with polytopic uncertainties. A BRL(bounded real lemma) for robust passivity with a dissipativity of discrete-time uncertain singular systems is derived. A low-order robust passive filter design method is proposed by new reduced-order method and LMI(linear matrix inequality) technique on the basis of the obtained BRL. Finally, illustrative examples are presented to show the applicability of the proposed method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.2
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• pp.115-122
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• 2002

In this paper, we proposed a new technique to be compatible the passive with active ETC system. Now the TTA is making a Standard of the Active DSRC System. So It is necessary to be compatible the developed and running passive ETC system with the developing active ETC system. So we proposed the direct conversion method without performance a decreasing of passive DSRC system using a similar bandwidth of the active ETC system. Simulations carried out and the results show the difference between the conventional and proposed method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.1
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• pp.92-106
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• 1990

Active compliance is often used in the control of robot manipulators for the implementation of complex tasks such as assembly, multi-finger fine motion, legged-vehicle adaptive control,etc. This technique balances the interactive force between the manipulator tip and its working environment with its position and velocity errors to achieve the operation of a damped spring. This paper investigates the effecft of passive compliance on system stability with regard to force feedback implementation for actively compliant motion. Usually it is understood that accurate position control require a stiff system. However, theoretical examination of control experiments on a legged suspension vehicle suggests that, if the control includes discrete-time force feedback, some passive compliance is necessssary at the legs of the vehicle for system stability. This can be an important factor to bl considered in manipulator design and control. A theoretical analysis, numerical simulation, and experimental result, confirming the above conclusion, are introduced in this paper.