• The Korean Journal of Health Service Management
• /
• v.7 no.3
• /
• pp.71-82
• /
• 2013

Arterial stiffness(AS) is an important pathologic state of vascular injury. This study was carried out to elucidate the effect of physiological variables on brachial-ankle pulse wave velocity(BAPWV), index of AS. Four hundred adults(volunteers) participated in this study. Body indices, biochemical, cardiac and inflammatory markers, and right(Rt)- and left(Lt)-BAPWV were measured. Body mass index(BMI), Rt- and Lt-BAPWV, glucose, triglyceride, alkaline phosphatase(ALP), gamma-glutamyl transferase(GGT), creatinine, uric acid, troponin-I(TNI), NT-proBNP and high sensitivity C-reactive protein(hs-CRP) levels were higher than the reference value of each variable. Rt- and Lt-BAPWV were directly correlated with age, body weight, BMI, glucose, ketone, aspartate aminotransferase, alanine aminotransferase, ALP, GGT, total cholesterol, low density lipoprotein, lipoprotein(a), apolipoprotein-B, blood urea nitrogen, heart rate, TNI, creatine kinase, CK-MB, lactic dehydrogenase, myoglobin, hs-CRP, lipase, reumatoid factor, fibrinogen and D-dimer (P<0.05, P<0.01, P<0.001 or P<0.000, respectively), but inversely associated with total bilirubin, uric acid, apolipoprotein-A1 and GFR (P<0.05). These observations suggest that a variety of physiological variables may influence BAPWV, resulting in increased risk or prevention of cardiovascular and/or cerebrovascular attacks. Therefore, physiological variables affecting BAPWV should be regularly controlled.

• 한국지구물리탐사학회:학술대회논문집
• /
• 1999.08a
• /
• pp.48-64
• /
• 1999

For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsurface velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etc. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data quality Geophone spacing of 3 to 5m is recommended in the land slope area for house land development and 5 to 10m in the tunnel site. In refraction tomography technique, the number of source points should be more than a half of available channel number of instrument, which can make topographic effect ignorable. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700${\~}$1,200m/s, soft rock 1,200${\~}$1,800m/s. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss. In case of tunnel site, it is recommended in tunnel design and construction to consider that tunnel is in contact with soft rock layer where three lineaments intersecting each other are recognized from the results of the other survey.

• The Journal of Engineering Geology
• /
• v.11 no.2
• /
• pp.163-174
• /
• 2001

For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsUJiace velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etC. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data Quality. Geophone spacing of 3 to 5m is reconunended in the land slope area of house land development site. In refraction tomography technique, the number of source points should be more than a Cluarter of available channel number of instrument and the subsurface structure interpretation can be decreased the artifact of inversion by topographic effect. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700~1,200m/s, soft rock 1,200~1,800m/s on the velocity tomogram section. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss.

• Journal of Nutrition and Health
• /
• v.55 no.4
• /
• pp.506-520
• /
• 2022

Purpose: Physical activity (PA) has a beneficial effect on the prevention of arteriosclerosis in healthy adults. The purpose of this study was to analyze the relationship between PA measured using an accelerometer and arterial stiffness in healthy Korean adults. Methods: This study involved 87 subjects (36.8% women) aged 20-64 years. PA was evaluated using an accelerometer (wGT3X-BT, ActiGraph, Florida, USA) for 7 days. Based on the results of the accelerometer measurement, subjects were classified into active and inactive groups according to the World Health Organization (WHO) PA guidelines. The brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI) to assess arterial stiffness were measured by a non-invasive vascular screening device (VP-1000 Plus, Omron). Results: The average age of the study subjects was 47.7 ± 11.3 years and the WHO PA guideline achievement rate was 29.9%. There was no significant difference in arterial stiffness (baPWV and ABI) between the active and inactive groups. In females, the time spent in light PA were positively correlated with ABI (r = 0.396; p < 0.05) and the number of sedentary bouts over 50 minutes was inversely correlated with ABI (r = -0.402; p < 0.05). However, there was no significant correlation between PA and arterial stiffness in males. Conclusions: The results of this study suggest that light PA and sedentary behavior have a positive correlation with arterial stiffness in females.

• The Journal of Engineering Geology
• /
• v.26 no.3
• /
• pp.339-352
• /
• 2016

The best way of investigating the physical and mechanical properties of subsurface materials is the combined interpretation of data from borehole geophysical surveys and geotechnical experiments with rock samples. In this study two surface seismic surveys with refraction and surface-wave method are alternatively conducted for downhole seismic surveys in test site for geological field trip in Jeungpyung, Chungbuk. P- and S-wave velocity structures are delineated by refraction and MASW (multichannel analysis of shear waves) methods, respectively. Possion's ratio section, reconstructed from P- and S-wave velocities, is correlated to the outcrop geological features consisting of reddish sedimentary rock, gray volcanic rock, and joints/fractures. In addition, rock samples representative for reddish sedimentary and gray volcanic features are geotechnically analyzed to provide physical, mechanical properties, and elastic modulus. Dynamic elastic moduli estimated from geophysical data is found to be higher than the one from geotechnical data. Reddish sedimentary rock characterized with low porosity and moisture content corresponds to the zone of low electrical resistivities and their small variations in the resistivity sections between the rainy and dry days. This trend suggests that the weathered gray volcanic rock and the nearby fractures with higher low porosity and moisture content are interpreted to be good carrier especially in rainy season.

• Geophysics and Geophysical Exploration
• /
• v.21 no.2
• /
• pp.103-111
• /
• 2018

The recent research aim of seismic trace interpolation is to effectively interpolate the data with spatial aliasing. Among various interpolation methods, the Matching Pursuit interpolation, that finds the proper combination of basis functions which can best recover traces, has been developed. However, this method cannot interpolate aliased data. Thus, the multi-component Matching Pursuit interpolation and moveout correction method have been proposed for interpolation of spatially aliased data. It is difficult to apply the multi-component Matching Pursuit interpolation to interpolating the OBC (Ocean Bottom Cable) data which is the multi-component data obtained at the ocean bottom because the isolation of P wave component is required in advance. Thus, in this study, we dealt with an effective single-component matching Pursuit interpolation method in OBC data where P-wave and S-wave are mixed and spatial aliasing is present. To do this, we proposed the Ricker wavelet based single-component Matching Pursuit interpolation workflow with moveoutcorrection and systematically investigated its effectiveness. In this workflow, the spatial aliasing problem is solved by applying constant value moveout correction to the data before the interpolation is performed. After finishing the interpolation, the inverse moveout correction is applied to the interpolated data using the same constant velocity. Through the application of our workflow to the synthetic OBC seismic data, we verified the effectiveness of the proposed workflow. In addition, we showed that the interpolation of field OBC data with severe spatial aliasing was successfully performed using our workflow.

• Geophysics and Geophysical Exploration
• /
• v.20 no.4
• /
• pp.207-215
• /
• 2017

To develope shale play which is one of unconventional energy resources, horizontal drilling and hydraulic fracturing are necessary and those are applied to the place where the differential horizontal stress ratio (DHSR) is low. The differential horizontal stress ratio is generally calculated by the minimum and maximum horizontal stress, but it is also calculated from dynamic elastic constants and anisotropic parameters. In this study we analyzed anisotropic properties through the core samples from Danyang limestone and calculated DHSR. The three types of core samples shaped in three directions (vertical, parallel and 45 degree to bedding) were used for laboratory test. We measured P-, S-wave velocities, and density and then calculated dynamic elastic constants, compliance and DHSR. According to the results of the core sample analysis the calculated DHSR is 0.185. Thomsen parameters of the Danyang limestone used in this study are characterized by the P- and S-wave velocities varying along the bedding symmetry axis. It is observed that the DHSR value is more affected by the change in compliance value than the Poisson's ratio. It is necessary to measure SH-wave velocity for more correct petrophysical properties.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.37 no.3_4
• /
• pp.61-71
• /
• 1995

Natural ground is a composite consisted of the three phases of water, air and soil paircies. Among the three components, water as a material is weU understood but soil particles are not in foundation engineering. Especially, weathered granite soil generally shows a large volumetric expansion when they freeze. And, the stability and durability of the soil have shown decreased with repetitive freezing and thawing processes. These unique charcteristics may cause various construction and management problems if the soil is used as a construction material and foundation layers. This project was initiated to investigate the soil's physical and engineering characteristics resulting from freezing and freezing-thawing processes. Research results may be used as a basic data in solving various problems related to the soil's unique characteristics. The following conclusions were obtained: The degree of decomposition of weathered granite soil in Kangwon-do was very different between the West and East sides of the divide of the Dae-Kwan Ryung. Soil particles distributed wide from very coarse to fine particles. Consistency could be predicted with a function of P200 as LL=0.8 P200+20. Permeability ranged from 10-2 to 10-4cm/sec, moisture content from 15 to 20% and maximum dry density from 1.55 to 1.73 g /cmΥ$^3$ By compaction, soil particles easily crushed, D50 of soil particles decreased and specific surface significantly increased. Shear characteristics varied wide depending on the disturbance of soil. Strain characteristics influenced the soil's dynamic behviour. Elastic failure mode was observed if strain was less than 1O-4/s and plastic failure mode was observed if strain was more than 10-2/s. The elastic wave velocity in the soil rapidly increased if dry density became larger than 1.5 g /cm$^3$ and these values were Vp=250, Vg= 150, respectively. Frost heave ratio was the highest around 0 $^{\circ}C$ and the maximum frost heave pressure was observed when deformation ratio was less than 10% which was the stability state of soil freezing. The state had no relation with frost depth. Over freezing process was observed when drainage or suction freezing process was undergone. Drainage freezing process was observed if freezing velocity was high under confined pressure and suction frost process was occurred if the velocity was low under the same confined process.

• Journal of the Korean Geophysical Society
• /
• v.4 no.2
• /
• pp.113-120
• /
• 2001

The discrete wavelet transform(DWT) has potential as a tool for supplying discriminatory attributes with which to distinguish seismic events. The wavelet transform has the great advantage over the Fourier transform in being able to localize changes. In this study, a discrete wavelet transform is applied to seismic traces for identifying seismic events and picking of arrival times for first breaks and S-wave arrivals. The precise determination of arrival times can greatly improve the quality of a number of geophysical studies, such as velocity analysis, refraction seismic survey, seismic tomography, down-hole and cross-hole survey, and sonic logging, etc. provide precise determination of seismic velocities. Tests for picking of P- and S- wave arrival times with the wavelet transform method is conducted with synthetic seismic traces which have or do not have noises. The results show that this picking algorithm can be successfully applied to noisy traces. The first arrival can be precisely determined with the field data, too.

• The Korean Journal of Physiology
• /
• v.26 no.1
• /
• pp.75-88
• /
• 1992

It is well established that neurons in ventrolateral medulla play a key role in determining the vasomotor tone. The purpose of present study is to identify sympathetic related, medullospinal tract neurons in ventrolateral medulla and to show that these mediate somato-sympathetic reflex. Medullospinal tract cells were identified by antidromic stimulation to intermediolateral nucleus (IML) of the second thoracic ($T_2$) spinal cord in anesthetized cats. Peripheral nerves were stimulated for orthodromic activation of these cells and peripheral receptive fields were determined. Post R wave histogram of unit and spike triggered averaging of sympathetic nerve discharge (SND) were used to define sympathetic related cell. A total of 113 neurons was recorded in ventrolateral medulla that had the axonal projections to $T_2$ spinal cord. Thirty four of these medullospinal cells showed spontaneous discharges and the others not. Between these two groups, rostro-caudal coordinate of the distribution from obex [$4.7{\pm}0.2\;$ (mean S.E.) mm, 4.1 0.1 mm], depth from dorsal surface ($5.5{\pm}0.2mm,\;4.9{\pm}0.1mm$ and conduction velocity ($9.9{\pm}1.7m/sec,\;16.7{\pm}1.9\;m/sec$) were significantly different (p<0.05). In spontaneously discharging group, characteristics of rostral and caudal groups were significantly different and we demonstrated that cells in rostral group mediate somatosympathetic reflex. From these results, we conclude that a certain portion of spontaneously discharging medullospinal tract cells in rostral ventrolateral medulla comprise the efferent outputs of somatosympathetic reflex to sympathetic preganglion neurons.