• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.1-12
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• 2003

The purpose of this study was to investigate the effect of high voltage pulsed current stimulation (HVPCS) on the healing rate of a dermal wound in a rat. We also determined the mechanism of promoting healing by HVPCS. Twenty male Sprague-Dawley rats were randomly divided into two group; HVPCS group (n=10) and control group (n=10). The HVPCS rats received electrical stimulation with a current intensity of 50 V at 100 pps for a duration of 30 minutes, while the control group was given the same treatment without electricity for a week. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with Masson's trichrome, hematoxylin and eosin (H&E). The fibroblasts and collagen density were counted using a light microscope and computerized image analysis system and calculated as the density and the percent. A Student t-test showed a significantly higher wound healing rate of the HVPCS group than control (t=-4.161, p<0.001). The fibroblasts in the HVPCS group were higher than in the control group (t=-4.921, p<0.001). The density of collagen in the HVPCS group was also higher than in the control group (t=-4.367, p<0.001). These results indicate that the HVPCS accelerated the rate of healing in dermal wound, and increased fibroblasts and collagen density in the regenerative dermis. These findings suggest that the HVPCS may activate fibroblasts by alteration of the electrical environment, and it may increase collagen synthesis in the regenerative dermal wound.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.289-292
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• 2010

본 연구에서는 ISM 밴드 소출력 무선 통신을 이용한 수액세트 감시시스템 개발에 대하여 연구하였다. 사회가 발전하면서 복지 수요가 증가되고 있으며 특히 의료 서비스에 대한 수요의 증가가 예상되고 있다. 유비쿼터스를 이용한 각종 의료장비들이 개발되고 있다. 본 논문에서는 병원의 응급실이나 중환자실과 같이 수액공급시 수액의 주입여부, 종료여부를 감시하는 수액세트 자동 감시시스템을 개발하고자 한다. 수액세트 감시장치는 센서부와 수신부로 구성되며, 센서부는 수액 백으로부터 수액이 공급중인지 여부를 검출하고 검출된 신호를 처리한 후 447MHz ISM 밴드의 무선주파수를 이용하여 중앙통제실로 전송한다. 센서부는 동전형 리튬전지를 이용하여 3개월 사용하도록 설계 구현하였고 실내에서최대 65m까지 전송이 가능하였다. 수신부는 센서부에서 전송된 데이터를 표시하는 기능을 한다.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.376-382
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• 2015

Dollar spot, caused by Sclerotinia homoeocarpa, is the major disease in cool-season turfgrasses. Understanding the distribution of this pathogen in soil and thatch is important to developing disease control strategies. In this study, toothpicks were used to detect S. homoeocarpa in the turfgrass canopy, thatch, and soil at different distances from dollar spot infection centers. The effect of penetrant and contact fungicide applications with different water volumes on distribution of S. homoeocarpa was also investigated. S. homoeocarpa was detected in 100% of samples taken from the leaf canopy, 83.3% in thatch area, and 0% in the soil from within the infection center. S. homoeocarpa was isolated in 100% of samples taken from the edge of the infection center, but was only detected in 13% of the samples taken at 1.5 cm away from the infection center edge. S. homoeocarpa was isolated at a higher frequency in the propiconazole treated plots than those treated with chlorothalonil and was not detected in leaf canopy samples when either fungicides was applied with 6.78 L of water. In conclusion, the toothpick-aided detection technique has improved our understanding of S. homoeocarpa epidemiology and could be used as a diagnostic tool to detect for fungicide resistance on golf courses.

• Membrane Journal
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• v.13 no.1
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• pp.37-46
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• 2003

The electrokinetic effect can be found in cases of the fluid flowing across the charged membrane micropores. The externally applied body force originated from the electrostatic interaction between the nonlinear Poisson-Boltzmann field and the flow-induced electrical field is taken into the equation of motion. The electrostatic potential profile is computed a priori by applying the finite difference scheme, and an analytical solution to the Navier-Stokes equation of motion for slit-like pore is obtained via the Green's function. An explicit analytical expression for the flow-induced streaming potential is derived as functions of relevant physicochemical parameters. The influences of the electric double layer, the surface potential of the wall, and the charge condition of the pore wall upon the velocity profile as well as the streaming potential are examined. With increasing of either the electric double layer thickness or the surface potential, the average fluid velocity is entirely reduced, while the streaming potential increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.218-223
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• 2008

Cell-phone becomes a necessary communication device in modern society. However, a paging signal by a sound transducer often acts as an unpleasant noise, thus necessitating a paging signal by a vibration motor. The conventional flat type vibration motor uses three-phase windings with three phase coils. In this article, a new design of a vibration motor using a V connection with two phase coils is presented, increasing mass productivity. For electromagnetic field analysis, due to the motor symmetry, two-dimensional modeling can be implemented for fast computation, and performance is predicted by the finite element method. The winding distribution angle turns out to be the most important design parameter for the elimination of dead points, and a new coil configuration is suggested which has no adverse effect on motor size and weight. Experimental tests of vibration confirm the validity of the proposed design.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.3
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• pp.151-160
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• 2014

In this study, the effect of the automotive haptic-seat technology which can transmit the driving information by the vibro-stimulus from the seat was investigated to overcome previous system's limitation relied on the visual and audial method and to help handicap driving. A prototype haptic seat cover with 30 coin-type motors and driver module were developed for this sake. In an experiment of seat vibration stimulation being performed under virtual driving situation by targeting the elderly aged over 65 years old, average score of test subjects for total vibration recognition was 3.5/4 points and recognition rate of 87.5% was represented. In addition, a result that all the test subjects totally recognized overspeed warning signal of 4 times was represented. As a result of statistical analysis for vibration recognition score by each group depending on TMT score, a significant difference was not found and a result that tactile function of which vibration is recognized even by the aged whose visual, perceptional function is declined showed an equal ability was obtained.. In this study it was shown that the seat vibration stimulus could be used to transfer the old drivers' information while driving.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.1-7
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• 2014

In this study, the effect of the automotive haptic-seat technology which can transmit the driving information by the vibro-stimulus from the seat was investigated to overcome previous system's limitation relied on the visual and audial method and to help handicap driving. A prototype haptic seat covers with 30 coin-type motors and driver module were developed for this sake. A driving simulator on the 6-DOF motion-base was used for driving situation and we executed the seat vibro-stimulus test with 10 young participants who have normal tactile sense. The haptic recognition ratio by 30 locations was measured and analyzed in the result. The intensity of vibro-stimulus was adjusted by input voltage of motors (1.5V,2.5V,3.5V). All vibro-stimulus locations at 2.5V and 3.5V could be recognized by all participants and even in the lowest recognition ratio of 1.5V. The results showed that the seat vibration stimulus could be useful to transfer the drivers' information while driving.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.3-12
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• 2016

Bluetooth Low Energy (BLE) protocol has attracted attention as a promising technology for low data throughput and low energy wireless sensor networks. Fast device discovery is very important in a BLE based wireless network. It is necessary to configure the network to work with minimized energy consumption because the BLE network nodes are expected to operate a long time typically on a coin cell battery. However, since it is difficult to obtain low energy and low latency at the same time, the BLE standard introduces wide range setting of parameters related to device discovery process and let the network operators to set up parameter values for the application. Therefore, it is necessary to analyze the performance of device discovery according to the related parameter values prior to BLE network operation. In this paper we analyze the expected value and the cumulative distribution function of the number of advertisements for device discovery in the BLE network. In addition, we propose a scheme for controlling the interval between advertising events that can improve the performance of device discovery without increasing energy consumption.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.131-139
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• 2005

On this study, I constructed the reflective acoustic signal detecting system using 15MHz acoustic transducer. The most difficult problems discriminating the characteristics of the metal substance are the discriminating the corrosion state and seeking hidden defects by using none destructive testing. For solving these problems, at first, theoretic analysis has been proceeded on the acoustic V(z) characteristics which is very important on discriminating the material characteristics. For application the V(z) theory to discriminating corrosion state, the 100 and 500 won metal coins which are issued on the different years are used as the test samples. The experimental results showed the distinct differences among the coin's acoustic signals accorded to its issued years. I catched the common regulation by analysing the acquisited acoustic signals and convinced this technique to be very useful on corrosion discrimination of the metal substances by none destructive testing and also can be used to inspect on the aeronautical materials for safety navigation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.9
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• pp.882-887
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• 2011

A spiral electrodynamic wheel is proposed as an actuator for the contactless conveyance of a conductive rod. When rotating the wheel around the rod, a radial force, a tangential force, and an axial force are generated on the rod and cause a screw motion of the rod. The rotation of the rod is the inevitable result due to traction torque of the wheel and the unintended motion to be excluded. However, the rotating speed of the rod should be measured without mechanical contact to be cancelled out through the controller, so the electrodynamic wheel is used as a sensor measuring the rotating speed of the rod indirectly as well as an actuator. In this paper, we model the magnetic forces by the proposed wheel theoretically and compare the derived model with simulation result by Maxwell, and analyze influences on the magnetic forces by key parameters constituting the wheel. The feasibility of the conveyance system is verified experimentally.