• Earthquakes and Structures
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• v.5 no.1
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• pp.111-127
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• 2013

This paper describes effects of infill walls on behavior of RC frame with low strength, including numerical modeling, modal testing and finite-element model updating. For this purpose full scaled, one bay and one story RC frame is produced and tested for plane and brick in-filled conditions. Ambient-vibration testis applied to identify dynamic characteristics under natural excitations. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are used to obtain experimental dynamic characteristics. A numerical modal analysis is performed on the developed two-dimensional finite element model of the frames using SAP2000 software to provide numerical frequencies and mode shapes. Dynamic characteristics obtained by numerical and experimental are compared with each other and finite element model of the frames are updated by changing some uncertain modeling parameters such as material properties and boundary conditions to reduce the differences between the results. At the end of the study, maximum differences in the natural frequencies are reduced on average from 34% to 9% and a good agreement is found between numerical and experimental dynamic characteristics after finite-element model updating. In addition, it is seen material properties are more effective parameters in the finite element model updating of plane frame. However, for brick in-filled frame changes in boundary conditions determine the model updating process.

• Journal of Acupuncture Research
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• v.27 no.3
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• pp.117-126
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• 2010

Objectives : The purpose of this study was to compare the effect of needle retention(NR) and electro-acupuncture of low(EA(L)) and high(EA(H)) frequencies at Haegye($ST_{41}$) on intestinal hypermotility induced with carbachol in rats Methods : We made over-activated state of intestinal motility with carbachol in rats and caried out needle retention acupuncture, low frequency electro-acupuncture and high frequency electro-acupuncture at Haegye($ST_{41}$) or sham point in rat devided into pre-treatment group and post-treatment group. And we resulted as followings from measuring charcoal travel rate with observation of intestinal motility. Results : 1. None of acupuncture, low frequency electro-acupuncture and high frequency electro-acupuncture at $ST_{41}$ had significant influences on intestinal motility of rat in normal state. 2. Pre-treated with acupuncture, low frequency electro-acupuncture and high frequency electro-acupuncture and post-treated with acupuncture and low frequency electro-acupuncture at $ST_{41}$ didn't significantly influences intestinal motility in rat which over-activated with carbachol. 3. Post-treated with high frequency electro-acupuncture at $ST_{41}$ suppressed intestinal motility in rat which over-activated with carbachol. Conclusions : These results suggest that treatment high frequency electro-acupuncture at ST41 may be effective on gastric disorders such as intestinal hypermotility and its effect had more cure than prevention.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.243-250
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• 2009

The expression of signal to noise ratio (SNR) is derived for the individual echo sounder and for the general specifications of commercial echo sounder. The SNR is depicted by several factors on transmitting and receiving, sound propagation, scattering by fishes, and mainly self ship noise. The detection ranges of echo sounders in depth and breadth are derived by finding the border of an acceptable SNR. The detection ranges are computed for the echo sounders of individual and general specifications. Generally, the detection range is lager for low frequencies. Increasing an electrical power and a diameter of transducer is not as effective for high frequencies as for low frequencies to increase the detection range. The theoretical results of the detection range can be applied to design low electrical power echo sounder for coastal use, to select an appropriate echo sounder, to know the capability of a sounder, and to interpret echograms. A method for evaluating and designing low electrical power echo sounder is developed. A universal diagram for the basic design of the low electrical power echo sounder where SNR is plotted against frequency is developed. An appropriate frequency, transducer diameter, and beam width are easily determined by using the diagram.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.1
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• pp.33-36
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• 2012

A total of 423 blood samples were collected (during 2009 and 2010) from all the ram holdings at three major Jordanian governmental Awassi breeding stations (Al-Khanasry, Al- Mushairfa and Al-Fjaje) and two private flocks. All blood samples were screened for the presence of mutations at the CNGA3 gene (responsible for day blindness in Awassi sheep) using RFLP-PCR. The day blindness mutation was detected in all studied flocks. The overall allele and genotype frequencies of all studied flocks of the day blindness mutation were 0.088 and 17.49%, respectively. The genotype and allele frequencies were higher in station flocks than the farmer flocks (0.121, 24.15 and 0.012, 2.32, respectively). Al-Mushairfa and Al-Khanasry stations have the highest genotype and allele frequencies for the day blindness mutation that were 27.77, 30.00% and 0.14, 0.171, respectively. The investigated farmer flocks have low percentages (0.03, 5.88% at Al-Shoubak and 0.005 and 1.05%, at Al-Karak, respectively for genotype and allele frequencies) compared with the breeding stations. Ram culling strategy was applied throughout the genotyping period in order to gradually eradicate this newly identified day blindness mutation from Jordanian Breeding station, since they annually distribute a high percentage of improved rams to farmer's flocks.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.3
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• pp.211-217
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• 2014

This study analyzes the nonlinear interaction between two different vortex shedding frequencies from a cylinder with two diameters. In particular, two different vortex shedding frequencies are generated by preparing a cylinder having two diameters artificially. Flow velocity fluctuations behind the cylinder are measured three-dimensionally. Additionally, we fabricated a hole and placed a pressure transducer for measuring the pressure on the cylinder surface. The pressure signal from the pressure transducer is used as basic signal. A TSC(Trans Spectrum Coherence) is used for checking the strength of the nonlinear interaction between two different vortex shedding frequencies. As a result, the following are clarified: i) frequency distribution behind the cylinder, ii) three-dimensional flow state behind the cylinder through calculation of ensemble average, and iii) close relationship between the vertical vortex and change of low frequency by nonlinear interaction between two different vortex shedding frequencies from the cylinder with two diameters.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.924-932
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• 1992

This paper presents the results of an experimental study on the characteristics of the vortex- induced vibration of an elastically supported circular cylinder in the cross air flow. For a range of velocities, power spectral densities of the signals from a hot-wire anemometer placed in the wake of an oscillating circular cylinder and gap sensors placed in the both ends of a circular cylinder were obtained to determine vortex-shedding frequencies, natural frequencies and vibrating frequencies of a cylinder. The effects of slots in the test section on vortex shedding and cylinder oscillation were investigated. The present study covered the reduced velocity range 1.0 .leg. Ur .leg. 64.6. The response characteristics of the cylinder has been shown to vary extensively, depending on the slots in the test section as well as on the reduced velocity. For an elastically supported cylinder, a purely translation mode oscillation was observed at a low velocity, however a rotation mode oscillation was often superposed for higher velocities. These two oscillating frequencies were equal to their natural frequencies irrespective of the changes of free stream velocities.

• Journal of Acupuncture Research
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• v.25 no.4
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• pp.105-116
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• 2008

Objectives : The aim of this study was to compare the effect of acpuncture and electroacupuncture of low(EA(L)) and high(EA(H)) frequencies at San Yin Jiu($SP_6$) and sham point in rats. We made suppressed state of intestinal motility with loperamide in rat and carried out needle retention acupuncture, low frequency electro-acupuncture and high frequency electro-acupuncture at ($SP_6$) in rat devided into pre-treatment group and post-treatment group. We fed charcoal to them after the treatment and measured the travel rate of charcoal in the gastrointestine track to analyze which treatment affected more in intestinal hypermotility Results : 1. Examining intestinal motility of normal rat treated with electro-acupuncture at $SP_6$, high frequency electro-acupuncture significantly increased intestinal motility. 2. Pre-treated with acupuncture at $SP_6$ significantly suppressed intestinal motility. 3. Post treatment with acupunture and low frequency electro-acupuncture at $SP_6$ showed significant increase of intestinal motility. Conclusions : As folowing study there were 21 groups to find out which treatment showed significant increase of intestinal motility and pre-treated acupuncture, post-treated with acupunture and low frequency electro-acupuncture at $SP_6$ was highly significant with control at the figure than any other groups.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.516-518
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• 1990

We have derived the equation which involves the variation of electron energy with time in a lowly ionized plasma when a low alternating electric field is applied. We consider only elastic collisions between electrons and neutral atoms. This equation is solved using the 4th-order Runge-Kutta method, and applied to argon gas discharge which is driven by source frequency of 100, 1K, 10K, 100K, and 1M (Hz). The results show that the variation of electron energy becomes flat with higher frequencies.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.147-147
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• 2003

Human exposure to benzene is derived occupationally from the petrochemical and petroleum refining industries. This study was carried out to find whether the frequencies of chromosome aberrations in workers exposed to low level benzene in a petroleum factory were elevated compared to non-exposed workers.(omitted)

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.50-57
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• 2007

Shocks are excited by impulsive forces and cause discomfort in vehicles. Current standards define means of evaluating shocks and predicting their discomfort, but the methods are based on research with a restricted range of shocks. This experimental study was designed to investigate the discomfort of seated subjects exposed to a wide range of vertical shocks. Shocks were produced from the responses of one degree-of-freedom models, with 16 natural frequencies (from 0.5 to 16 Hz) and four damping ratios (0.05 0.1, 0.2 and 0.4), to a hanning-windowed half-sine force inputs. Each type of shock was presented at five vibration dose values in the range $0.35\;ms^{-1.75}$ to $2.89\;ms^{-1.75}$. Fifteen subjects used magnitude estimation method to judge the discomfort of all shocks. The exponent in Stevens' power law, indicating the rate of growth in discomfort with shock magnitude, decreased with increasing fundamental frequency of the shocks. At all magnitudes, the equivalent comfort contours showed greatest sensitivity to shocks having fundamental frequencies in the range 4 to 12.5 Hz. At low magnitudes the variations in discomfort with the shock fundamental frequency were similar to the frequency weighting $W_b$ in BS 6841, but low frequency high magnitudes shocks produced greater discomfort than predicted by this weighting. At some frequencies, for the same unweighted vibration dose value, there were small but significant differences in discomfort caused by shocks having different damping ratios. The rate of increase in discomfort with increasing shock magnitude depends on the fundamental frequency of the shock. In consequence, the frequency-dependence of discomfort produced by vertical shocks depends on shock magnitude. For shocks of low and moderate discomfort, the current methods seem reasonable, but the response to higher magnitude shocks needs further investigation.