• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.1964-1966
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• 2001

Active Noise control(ANC) is rapidly becoming the most effective way to reduce noises that can otherwise be very difficult and expensive to control. This research presents ANFIS (Adaptive Network Fuzzy Inference System) controller for adaptively noise cancelling in a duct. ANC system generates secondary control sound pressure with same amplitude and with opposite phase as noise to be eliminated. ANFIS controller is trained to optimize its parameters for adaptively cancelling noise. That is ANFIS train its parameters by gradient descent and LSE method so called hybrid method. This paper present ANFIS in active noise control which provides an improvement convergence speed and limitation of linearity condition. It can model nonlinear functions of arbitrary complexity and ANFIS can construct an input-ouput mapping based on both human knowledge in the form of Takagi and Sugeno's fuzzy if-then rules and stipulated input-output data pairs. This paper also shows that the proposed ANFIS active noise control system successfully cancelled noise.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.286-291
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• 2019

Purpose: This study examined the effects of self-volar gliding combined with a strap and wrist distraction on pain and the active and passive wrist extension range of motion (ROM) in subjects with dorsal wrist pain during partial weight bearing of the hand. Methods: Thirty subjects (14 males and 16 females) with dorsal wrist pain during partial weight bearing through the hand participated in this study. The two different self-volar gliding techniques were performed for each group. Self-volar gliding using a strap (SVGS) and SVGS and wrist distraction (SVGSD) were performed five times for one week for each group. The active and passive ROM of wrist extension and the peak pressure pushed by the hand at pain (PPHP) were measured. An independent t-test was used to compare the improvements of these elements between the two different self-volar gliding techniques. The level of statistical significance was at ${\alpha}=0.05$. Results: The active and passive ROM of wrist extension and PPHP were greater in both self-volar gliding groups after the one week intervention. On the other hand, these parameters were greater in the SVGSD group than in the SVGS group (p<0.05) Conclusion: SVGSD is recommended to improve the active and passive ROM of wrist extension and PPHP in subjects with dorsal wrist pain during partial weight bearing of the hand.

• The Journal of Korean Physical Therapy
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• v.22 no.3
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• pp.17-21
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• 2010

Purpose: This study was designed to investigate possibilities for quantitative analysis using the electromyography and sonography. For better understanding, we evaluated the correlation between the pressure pain threshold and sonography, spontaneous electrical activity in trigger points located in the upper trapezius muscle. Methods: Thirty three active subjects volunteered to participate in this study (n=33). They had a palpable taut band, exquisite spot tenderness of a nodule in a taut band, spontaneous pain, referred pain, jump sign, local twitch response, and a painful limit to full stretch range of motion. We measured Pressure pain threshold, density, white area index, root mean square, and reaction. Pearson’s correlation coefficient was calculated to estimate the relationship between the pressure pain threshold and other variables including density, white area index, root mean square, and reaction time. Results: There were significant correlations between pressure pain threshold and density (r=-0.75, p<0.01), and between pressure pain threshold and white area index (r=-0.74, p<0.01). A significant correlations between pressure pain threshold and root mean square (r=-0.59, p<0.01). The significant correlation was found between pressure pain threshold and reaction time (r=-0.64, p<0.01). Conclusion: These should indicate whether quantitative analysis can be done using the characteristics of electromyography and sonography.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.192-200
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• 2002

Semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspensions for passenger cars. In this study, a continuous variable damper for a passenger car suspension is developed, which is controlled actively and exhibits high performance with light weight, low cost, and low energy consumption. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper that offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that rebound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-off becomes smooth when the fixed orifice size increases, which means that the blow-off slope is controllable using the fixed orifice size. The damping force variance is wide and continuous, and is controlled by the spool opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to be utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is confirmed through real car test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1472-1477
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• 2005

Recently, the performance development of the exhaust system of a car is very important. The most important part of parts that constructing the exhaust system of a car is a muffler. The muffler reducing the exhaust noise from the engine influence on the engine performance directly. The inner parts of the muffler construct with the baffle and perforated pipes and so on. In the recent study, the study to design the semi-active muffler sensing the exhaust gas pressure controlling the back pressure variably with a EVV progress activity. So that the inner parts of the muffler show the complicated turbulent flow phenomena because of pulsatile flow from the engine and the structural properties and so on. The qualitative and quantitative analysis about the turbulent flow phenomena of the inner parts of the muffler is required gradually. In this study, to analysis the flow field of the inner parts of the muffler, analysis results with the PIV measurement to be able to analysis the variable change of the time and the space. Therefore, try to show the design variables to need to design the inner parts of a muffler of a car.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.3
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• pp.87-99
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• 2009

Objectives : The study was to examine the empirical evidence concerning the effects of massage intervention for the laboring women and to investigate the effect sizes related to the characteristics of intervention. Methods : Meta analysis was performed. A total of 11 trials related to massage intervention between 2000 and 2007 were reviewed. Results : Massage intervention showed a beneficial effect on length of labor(1st stage : U=46.75, p=0.00, 2nd stage : U=6.13, p=0.01), perception of childbirth experience(U=12.57, p=0.00), intensity of uterine contraction at the active(U=6.34, p=0.01) and the transition phases(U=24.83, p=0.00), and interval of uterine contraction at the active phase(U=4.83, p=0.03). Massage decreased systolic(U=10.81, p=0.00) and diastolic blood pressure at the transition phase(U=10.60, p=0.00). However, massage had no effect on subjective and objective labor pain and anxiety. No differences were found in effectiveness of massage according to characteristics of intervention(massage material, massager, and massage site) except for anxiety(QB=4.82, p=0.03) and diastolic blood pressure at the active phase by massage site(QB=4.52, p=0.03). Conclusions :We found that massage intervention for the laboring women had an empirical evidence on improving perception of childbirth experience and shortening length of labor. These results should be interpreted with caution due to the lack of studies. More full-scale randomized clinical trials with reliable designs are recommended to further warrant the effectiveness of massage.

• Structural Engineering and Mechanics
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• v.20 no.5
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• pp.543-558
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• 2005

The natural frequencies of a long span bridge vary during its construction and it is thus difficult to apply traditional tuned liquid column dampers (TLCD) with a fixed configuration to reduce bridge vibration. The restriction of TLCD imposed by frequency tuning requirement also make it difficult to be applied to structure with either very low or high natural frequency. A semi-active tuned liquid column damper (SATLCD), whose natural frequency can be altered by active control of liquid column pressure, is studied in this paper. The principle of SATLCD with adaptive tuning capacity is first introduced. The analytical models are then developed for lateral vibration of a structure with SATLCD and torsional vibration of a structure with SATLCD, respectively, under either harmonic or white noise excitation. The non-linear damping property of SATLCD is linearized by an equivalent linearization technique. Extensive parametric studies are finally carried out in the frequency domain to find the beneficial parameters by which the maximum vibration reduction can be achieved. The key parameters investigated include the distance from the centre line of SATLCD to the rotational axis of a structure, the ratio of horizontal length to the total length of liquid column, head loss coefficient, and frequency offset ratio. The investigations demonstrate that SATLCD can provide a greater flexibility for its application in practice and achieve a high degree of vibration reduction. The sensitivity of SATLCD to the frequency offset between the damper and structure can be improved by adapting its frequency precisely to the measured structural frequency.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.104-109
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• 2018

A non-intrusive ECG and BCG measurement system is introduced. The system is built on a auxiliary backrest of a chair. The developed system is aimed to non-intrusive assessment of cardiovascular dynamic indices such as pulse arrival time(PAT) and pre-ejection period (PEP). In the system, capacitive active electrodes and capacitive grounding were used for the non-intrusive indirect-contact ECG measurement, and EMFi pressure sensor was used for the non-intrusive BCG measurement. The capacitive active electrodes and the EMFi sensor were attached on the backrest. Using the system, ECG and BCG were successfully acquired. The measured BCG showed peaks that following ECG R peaks. It was shown that the time interval between Q wave in ECG and first peak in BCG correlates Pre-ejection period measured by impedance-cardiogram. The results showed that the introduced system can be used for the non-intrusive various cardiovascular information including ECG, PAT, PEP.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.106-106
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• 2011

Recently, zinc oxide (ZnO) thin films have attracted great attention as a promising candidate for various electronic applications such as transparent electrodes, thin film transistors, and optoelectronic devices. ZnO thin films have a wide band gap energy of 3.37 eV and transparency in visible region. Moreover, ZnO thin films can be deposited in a poly-crystalline form even at room temperature, extending the choice of substrates including even plastics. Therefore, it is possible to realize thin film transistors by using ZnO thin films as the active channel layer. In this work, we investigated influence of oxygen partial pressure on ZnO thin films and fabricated ZnO-based thin film transistors. ZnO thin films were deposited on glass substrates by using a pulsed laser deposition technique in various oxygen partial pressures from 20 to 100 mTorr at room temperature. X-ray diffraction (XRD), transmission line method (TLM), and UV-Vis spectroscopy were employed to study the structural, electrical, and optical properties of the ZnO thin films. As a result, 80 mTorr was optimal condition for active layer of thin film transistors, since the active layer of thin film transistors needs high resistivity to achieve low off-current and high on-off ratio. The fabricated ZnO-based thin film transistors operated in the enhancement mode with high field effect mobility and low threshold voltage.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.667-674
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• 2017

Angiotensin II (Ang II) is metabolized from N-terminal by aminopeptidases and from C-terminal by Ang converting enzyme (ACE) to generate several truncated angiotensin peptides (Angs). The truncated Angs have different biological effects but it remains unknown whether Ang-(4-8) is an active peptide. The present study was to investigate the effects of Ang-(4-8) on hemodynamics and atrial natriuretic peptide (ANP) secretion using isolated beating rat atria. Atrial stretch caused increases in atrial contractility by 60% and in ANP secretion by 70%. Ang-(4-8) (0.01, 0.1, and $1{\mu}M$) suppressed high stretch-induced ANP secretion in a dose-dependent manner. Ang-(4-8) ($0.1{\mu}M$)-induced suppression of ANP secretion was attenuated by the pretreatment with an antagonist of Ang type 1 receptor ($AT_1R$) but not by an antagonist of $AT_2R$ or $AT_4R$. Ang-(4-8)-induced suppression of ANP secretion was attenuated by the pretreatment with inhibitor of phospholipase (PLC), inositol triphosphate ($IP_3$) receptor, or nonspecific protein kinase C (PKC). The potency of Ang-(4-8) to inhibit ANP secretion was similar to Ang II. However, Ang-(4-8) $10{\mu}M$ caused an increased mean arterial pressure which was similar to that by 1 nM Ang II. Therefore, we suggest that Ang-(4-8) suppresses high stretch-induced ANP secretion through the $AT_1R$ and $PLC/IP_3/PKC$ pathway. Ang-(4-8) is a biologically active peptide which functions as an inhibition mechanism of ANP secretion and an increment of blood pressure.