• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.7
• /
• pp.534-541
• /
• 2002

Vibration and sound characteristics of King Song-Dok Bell are ivesigated. Natural frequencies. vibration modes and beat period of the bell are precisely measured. The effect of striking position and the position of nodal lines on the beat characteristics is examined. It is first found that the beat characteristics are quote different according to the position on the bell surface and clear beat is periodically generated on the circumference. It turns out that in King Song-Dok Bell, Dangjwa(the present striking position) is located at the position which makes a beat in the first vibration mode, as welt as it produces very clear beat In the second vibration mode.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.4
• /
• pp.435-445
• /
• 2019

Ball screw drives are widely used in industry, and many studies have been devoted on precise, fast and robust control of ball screw drives. In this study, a novel position control algorithm for ball screw drives is proposed, which consist of a PD controller, a friction feedforward and a disturbance observer. The dynamics and the position error of such controller are analyzed to establish an error model, which can be used to predict the resulting position error of the given desired trajectory. Using the proposed error model, the desired trajectory can be modified so that the predicted position error can be compensated in a feedforward manner. The proposed algorithm does not require the model of the system for the error prediction, and thus can be easily applied to conventional control systems. The performance of the system is verified through simulations and experiments.

• Maritime Security
• /
• v.1 no.1
• /
• pp.31-59
• /
• 2020

The purpose of this study is to clarify why Russia has changed its position on the Caspian Sea Convention to allow cross-Caspian routes. The theory that explains Russia's change of position on Eurasian integration suggests isolation from the West and rising political and economic importance in the Asia-Pacific as cause, but fails to explain the cause of the change in position that could allow Western influence. Thus, this article suggests that a change in Russia's perception on expanding Eurasia's influence as the cause of the change on its position on the Caspian Sea.

• Journal of ILASS-Korea
• /
• v.28 no.3
• /
• pp.134-142
• /
• 2023

Electric field assisted combustion is a method that reduces instability in lean combustion. In this study investigated the effects of electrode position on propane-air flame characteristic using a ring electrode. Results showed that burning velocity was not affected by electrode position, but positive voltage expanded the flammability limit while negative voltage contracted it. The effect of voltage polarity on the flammability limit decreased as the electrode position increased. Expanding the flammability limit with a positive voltage can reduce NOx emissions.

• Physical Therapy Korea
• /
• v.16 no.4
• /
• pp.8-15
• /
• 2009

Grip strength is an objective indicator for evaluating the functional movement of upper extremities. Therapists have been using it for a long time as an excellent barometer for evaluating the therapy process, therapeutic effects and prognosis of patients with injuries in upper extremities. This study investigated the effects of extensor pattern position and elastic taping of non-dominant hand on the grip strength of dominant hand among general adults. The subjects of this study were 23 males and 7 females from physical therapy departments of 3 Universities located in Busan who agreed to participate in the experiment and the resultant data were analyzed using SPSS version 12.0. The results of the study were as follows. First, there was a significant difference between the grip strength of dominant hand when the non-dominant hand was at the neutral position and that when the non-dominant hand was at the extensor pattern position and both hands were at the maximum strength simultaneously (Bonferroni-corrected p<.001). Second, there was a significant difference between the grip strength of dominant hand when the non-dominant hand was at the neutral position and that when the elastic taping of non-dominant hand was applied (Bonferroni-corrected p<.001). Third, there was no significant difference between the grip strength of dominant hand when the non-dominant hand was at the extensor pattern position and both hands were at the maximum strength simultaneously and that when the elastic taping of non-dominant hand was applied. The irradiation effects through the extensor pattern position of non-dominant hand and application of the elastic taping to non-dominant hand showed significant results in improving the maximum grip strength of dominant hand. This finding could be suggested as the probability for the indirect treatment of the upper extremities of hemiplegia and orthopedic patients due to the long-term fixing of upper extremities.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.6
• /
• pp.516-523
• /
• 2001

This paper introduces a indirect rotor position and speed estimation algorithm for the SRM(switched reluctance motor) sensorless control based on the sliding mode observer and evolutionary programming The information of position and speed is generally provided by encoder or resolve. However, the position sensor not only adds complexity, cost and size to the whole drive system, but also causes limitation for industrial applications. In this paper, in order to eliminate the position sensor, indirect position sensing, indirect position sensing method using sliding mode observer is used for SRM drives. But if sliding mode observer parameters are selected to be large, the corresponding rapid changes of estimated position and velocity result in chattering phenomenon. Therefore in order to reduce the chattering, this observer parameters are optimized by evolutionary programming. And PID controller is also optimized to track precisely for the SRM using evolutionary programming.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.54 no.2
• /
• pp.181-187
• /
• 2018

In order for the probe to perform ocean exploration and survey research, it is necessary to adjust the position of the ship as desired by dynamic positioning system. The dynamic positioning system of T/S NARA is applied to K-POS dynamic positioning system of Kongsberg, which makes maintaining the ship's position, changing position and heading control possible. T/S NARA is not capable of dynamic positioning if one or more propulsive forces are lost with DP Level One. However, it is predicted that dynamic positioning can be achieved even at the time of missing one thrust in a good sea condition. Therefore, we want to analyze the effect of each propulsion on the performance of dynamic position system. When one of the bow thruster and azimuth thrusters lost their propulsion, maintaining the ship's position, changing position and heading control performance were compared and analyzed. If the situation occurred disable from using the bow thruster, they can not maintain ship's position. Azimuth thruster was influential for the ship's position control and bow thruster was influential in heading control. The excellent dynamic positioning performance can be achieved, considering the propulsion power that will have a impact on each situation in the future.

• Physical Therapy Korea
• /
• v.26 no.3
• /
• pp.23-31
• /
• 2019

Background: Measurement of passive ankle dorsiflexion range of motion (ADROM) is often part of a physical therapy assessment. Objects: The objective of this study was to identify the effects of subtalar joint neutral position (SJNP) on passive ADROM according to knee position in young adults. Methods: We recruited 14 young adult participants for this study. Two examiners used a universal goniometer to measure passive ADROM with and without SJNP. Dorsiflexion force was applied to the forefoot until maximum resistance was reached in two knee positions (extension and $90^{\circ}$ flexion) in the prone position. Subtalar joint position was also recorded at maximum ADROM. Passive ADROM was measured three times at different knee and subtalar joint positions, in random order. Two-way repeated-measures analysis of variance was used to compare the effects of subtalar joint and knee position on passive ADROM. Results: Passive ADROM was significantly lower with than without SJNP during both knee extension (mean difference: $7.4^{\circ}$) and $90^{\circ}$ flexion (mean difference: $16.9^{\circ}$) (p<.01). Passive ADROM was significantly higher during $90^{\circ}$ knee flexion than during knee extension both with (mean difference: $5.8^{\circ}$) and without SJNP (mean difference: $15.2^{\circ}$) (p<.01). The valgus position of the subtalar joint was significantly lower with than without SJNP during both knee extension (mean difference: $3.3^{\circ}$) and $90^{\circ}$ flexion (mean difference: $4.3^{\circ}$) (p<.01). Conclusion: Our results indicate that the gastrocnemius may limit ankle dorsiflexion more than the soleus does. Greater dorsiflexion at the subtalar and midtarsal joints was observed during passive ADROM measurement without than that with SJNP; therefore, SJNP should be maintained for accurate measurement of ADROM.

• International Journal of Advanced Culture Technology
• /
• v.12 no.2
• /
• pp.368-374
• /
• 2024

During an X-ray examination, the beam of radiation is dispersed in many directions. We believe that managing radiation dose is about providing transparency to users and patients in the accurate investigation and analysis of radiation dose. The purpose of measuring the radiation dose as a function of location is to ensure that medical personnel using the equipment or participating in the operating room are minimally harmed by the different radiation doses depending on their location. Four mobile diagnostic X-ray units were used to analyze the radiation dose depending on the spatial location. The image intensifier and the flat panel detector type that receives the image analyzed the dose by angle to measure the distribution of the exposure dose by location. The radiation equipment used was composed of four units, and measuring devices were installed according to the location. The X-ray (C-arm) was measured by varying the position from 0 to 360 degrees, and the highest dose was measured at the center position based on the abdominal position, and the highest dose was measured at the 90° position for the head position when using the image intensifier equipment. The operator or medical staff can see that the radiation dose varies depending on the position of the diagnostic radiation generator. In the image intensifier and flat panel detector type that accepts images, the dose by angle was analyzed for the distribution of exposed dose by position, and the measurement method should be changed according to the provision of dose information that is different from the dose output from the equipment according to the position.

• Journal of the Korean Society of Physical Medicine
• /
• v.8 no.3
• /
• pp.327-335
• /
• 2013

PURPOSE: The purpose of this study is to investigate effects of trunk position sense through visual cue deprivation balance training in subacute stroke patients. METHODS: The subjects were randomly allocated to two groups: experimental(n=10) and control(n=10). Both groups performed balance training on sitting for 30minute after measurements. Trunk position sense test was assessed using the David back concept to determine trunk repositioning error for four movement(flexion, extension, affected side lateral flexion, non-affected side lateral flexion). Measurements on each test were assessed prior to the balance training and then immediately following the balance training. RESULTS: In comparison of the difference of the trunk position sense between groups, the experimental group decreased significantly in trunk repositioning error of flexion, extension and affected side lateral flexion than control group(p<.05). CONCLUSION: The trunk position sense of the experimental group showed more improvement after the balance training program compared to the control group, Therefore, these results suggest that visual cue deprivation training is considered an effective exercise method for individuals with subacute stroke.