• The Korean Journal of Physiology
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• v.23 no.2
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• pp.263-275
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• 1989

Mechanical contractions and electrical activities of the fundic longitudinal and antral circular muscle fibers were investigated in order to elucidate topical differences of gastric motility. K-induced contracture was produced by exposure of muscle strips to high K Tyrode solution. Membrane potential and mechanical contraction were simultaneously recorded by conventional glass microelectrode method and single sucrose-gap technique. All experiments were performed in tris-buffered Tyrode solution which was aerated with $100%\;O_2\;and\;kept\;35^{\circ}C$. The results obtained were as follows: 1) The resting membrane potential of circular muscle cells in the antral region was about 10 mV more negative than that in the fundic region. 2) The membrane potentials decreased almost linearly as the extracellular KCI concentration was increased both in antral circular muscle cells and in fundic longitudinal muscle cells. 3) The thresholdal K concentration of K-contracture was 15 mM (membrane potential, -48 mV) for the antral circular muscle strip and 20 mM for the fundic longitudinal muscle cells. 4) The ratio of membrane permeability coefficient for $Na^+\;and\;K^+,\;P_{Na}/P_K\;({\alpha})$ was 0.065 for antral circular muscle cells and was 0.108 for fundic longitudinal muscle cells. 5) K-contracture of antral and fundic smooth muscle strips showed the contracture composed of phasic and tonic components. The amplitude of the phasic component increased sigmoidally in a dose-dependent manner, whereas that of the tonic component was maximal at a concentration of 40 mM KCI and at the concentrations above or below 40 mM KCI the amplitude was reduced. 6) The inverse relationship between the amplitude of tonic component and extracellular KCI concentration in the range of 40 to 150 mM KCI was more prominent in the antral circular muscle strip than in the fundic longitudinal muscle strip, where the amplitude of the tonic component decreased less steeply and was maintained higher at the same high K concentrations. 7) The tonic component was totally dependent on the external $Ca^{2+}$ and completely abolished by verapamil, while tile phasic component was far less dependent on the external $Ca^{2+}$ and partially suppressed by verapamil. From the above results, the following conclusions could be made. 1) The phasic component of K-contracture is produced both by intracellular $Ca^{2+}$ mobilization and by $Ca^{2+}$-influx from outside, while the tonic component is generated and maintained by the $Ca^{2+}-influx$ through the potential-dependent $Ca^{2+}$ channel. 2) The mechanism of reducing the free $Ca^{2+}$ concentration in the myoplasm seems to be more developed in the antral circular muscle than in the fundic longitudinal muscle. 3) The lower resting membrane potential of the fundic longitudinal muscle cell reflects a relatively high $P_{Na}/P_K$ ratio of about 0.108.

• Journal of the Korean GEO-environmental Society
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• v.17 no.4
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• pp.33-37
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• 2016

The hydration process of Controlled Low Strength Material (CLSM) used for backfill is the primary factor to determine the construction period. The objective of this study is to monitor the hydration process of CLSM using the Time Domain Reflectometry (TDR) and to establish the relationship between dielectric constant and compressive strength. The CLSM specimen is composed of cement, flyash, silt, sand, accelerator, and water. The material characteristics of the CLSM including flow, unit weight, compressive strength are investigated. To measure the dielectric constant of the CLSM during the curing time, TDR probe incorporated with a mold and a reflectometer are used. Experimental results show that the dielectric constant remains constant at early stage, and then decreases as the curing time increases. In addition, the dielectric constant is related to the compressive strength in inverse power function. This paper suggests that the TDR technique may be used as a non-destructive testing method in order to estimate the compressive strength of the CLSM mixture under construction.

• Journal of the Korean GEO-environmental Society
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• v.9 no.6
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• pp.31-41
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• 2008

Consolidation characteristics of reclamated ground with dredged soil and methods of evaluating them are investigated in this paper. For a dredged and reclamated ground with a very high water content, self-weight consolidation being progressed, its consolidation characteristics are difficult to find since it is almost impossible to have a undisturbed sample. In order to overcome such a problem, methods of laboratory tests with disturbed sample were studied to obtain consolidation parameters required to analyze consolidation settlement in practices, using the conventional infinitesimal consolidation theory, were evaluated by carrying out various laboratory tests with disturbed soils such as oedometer test, constant rate of deformation test, Rowe-cell tests with ring diameters of 60 mm, 100 mm and 150 mm and the centrifuge model tests with 40 g-levels. Constitutive relations of void ratio - effective vertical stress - permeability were evaluated by using the inverse technique implemented with the finite strain consolidation theory and results of centrifuge model tests. Design soil parameters related to consolidation such as compression index, swelling index, coefficient of volume change and vertical and horizontal consolidation coefficients were proposed properly by analyzing the various test results comprehensively.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.06a
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• pp.3-17
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• 2004

Space-borne Earth observation technique is one of the most cost effective and rapidly advancing Earth science research tools today and the potential field and micro-wave radar applications have been leading the discipline. The traditional optical imaging systems including the well known Landsat, NOAA - AVHRR, SPOT, and IKONOS have steadily improved spatial imaging resolution but increasing cloud covers have the major deterrent. The new Earth observation satellites ENVISAT (launched on March 1 2002, specifically for Earth environment observation), ALOS (planned for launching in 2004 - 2005 period and ALOS stands for Advanced Land Observation Satellite), and RADARSAT-II (planned for launching in 2005) all have synthetic aperture radar (SAR) onboard, which all have partial or fully polarimetric imaging capabilities. These new types of polarimetric imaging radars with repeat orbit interferometric capabilities are opening up completely new possibilities in Earth system science research, in addition to the radar altimeter and scatterometer. The main advantage of a SAR system is the all weather imaging capability without Sun light and the newly developed interferometric capabilities, utilizing the phase information in SAR data further extends the observation capabilities of directional surface covers and neotectonic surface displacements. In addition, if one can utilize the newly available multiple frequency polarimetric information, the new generation of space-borne SAR systems is the future research tool for Earth observation and global environmental change monitoring. The potential field strength decreases as a function of the inverse square of the distance between the source and the observation point and geophysicists have traditionally been reluctant to make the potential field observation from any space-borne platforms. However, there have recently been a number of potential field missions such as ASTRID-2, Orsted, CHAMP, GRACE, GOCE. Of course these satellite sensors are most effective for low spatial resolution applications. For similar objects, AMPERE and NPOESS are being planned by the United States and France. The Earth science disciplines which utilize space-borne platforms most are the astronomy and atmospheric science. However in this talk we will focus our discussion on the solid Earth and physical oceanographic applications. The geodynamic applications actively being investigated from various space-borne platforms geological mapping, earthquake and volcano .elated tectonic deformation, generation of p.ecise digital elevation model (DEM), development of multi-temporal differential cross-track SAR interferometry, sea surface wind measurement, tidal flat geomorphology, sea surface wave dynamics, internal waves and high latitude cryogenics including sea ice problems.

• Nuclear Engineering and Technology
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• v.46 no.3
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• pp.439-446
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• 2014

An amphibious inspection robot system (hereafter AIROS) is being developed to visually inspect the in-containment refueling storage water tank (hereafter IRWST) strainer in APR1400 instead of a human diver. Four IRWST strainers are located in the IRWST, which is filled with boric acid water. Each strainer has 108 sub-assembly strainer fin modules that should be inspected with the VT-3 method according to Reg. guide 1.82 and the operation manual. AIROS has 6 thrusters for submarine voyage and 4 legs for walking on the top of the strainer. An inverse kinematic algorithm was implemented in the robot controller for exact walking on the top of the IRWST strainer. The IRWST strainer has several top cross braces that are extruded on the top of the strainer, which can be obstacles of walking on the strainer, to maintain the frame of the strainer. Therefore, a robot leg should arrive at the position beside the top cross brace. For this reason, we used an image processing technique to find the top cross brace in the sole camera image. The sole camera image is processed to find the existence of the top cross brace using the cross edge detection algorithm in real time. A 5-DOF robot arm that has multiple camera modules for simultaneous inspection of both sides can penetrate narrow gaps. For intuitive presentation of inspection results and for management of inspection data, inspection images are stored in the control PC with camera angles and positions to synthesize and merge the images. The synthesized images are then mapped in a 3D CAD model of the IRWST strainer with the location information. An IRWST strainer mock-up was fabricated to teach the robot arm scanning and gaiting. It is important to arrive at the designated position for inserting the robot arm into all of the gaps. Exact position control without anchor under the water is not easy. Therefore, we designed the multi leg robot for the role of anchoring and positioning. Quadruped robot design of installing sole cameras was a new approach for the exact and stable position control on the IRWST strainer, unlike a traditional robot for underwater facility inspection. The developed robot will be practically used to enhance the efficiency and reliability of the inspection of nuclear power plant components.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.123-138
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• 2018

To sustainably monitor air pollution in Seoul, the number of Air Pollution Monitoring Station has been gradually increased by Korea's Ministry of Environment. Although particulate matters(PM), one of the pollutants measured at the stations, have an significant influence on human body, the concentration of PM in Korea came in second among 35 OECD member countries. In this study, using the data of PM concentration from the stations, distribution maps of PM10 and PM2.5 concentrations over Seoul were generated, and spatial factors potentially related to PM distribution were investigated. Based on a circumscribed hexagon about a circle in radius of 500 meters created as a basic unit, Seoul was sectionalized and PM concentration map was generated using the interpolation technique of 'inverse distance weighting'. The distributions of PM concentrations were investigated with commuting time by administrative district and the outcome was related with land-use type and volume of traffic. Results from this analysis indicated distribution pattern of PM10 concentration was different from that of PM2.5 by administrative district and time. The distribution of PM concentration was strongly related to not only the size of business and trafficked areas among the land-use type, but also the existence of urban green. Further analysis of the relationship between the PM concentration and detailed land-use and urban green maps can be helpful to identify spatial factors which have an impact on the PM concentration on the regional scale.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.706-715
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• 2004

In this paper, to decide the watermark embedding positions and embed the watermark we use the subband tee structure which is presented in the wavelet domain and the edge information in the spatial domain. The significant frequency region is estimated by the subband searching from the higher frequency subband to the lower frequency subband. LH1 subband which has the higher frequency in tree structure of the wavelet domain is divided into 4${\times}$4 submatrices, and the threshold which is used in the watermark embedding is obtained by the blockmatrix which is consists by the average of 4${\times}$4 submatrices. Also the watermark embedding position, Keymap is generated by the blockmatrix for the energy distribution in the frequency domain and the edge information in the spatial domain. The watermark is embedded into the wavelet coefficients using the Keymap and the random sequence generated by LFSR(Linear feedback shift register). Finally after the inverse wavelet transform the watermark embedded image is obtained. the proposed watermarking algorithm showed PSNR over 2㏈ and had the higher results from 2％ to 8％ in the comparison with the previous research for the attack such as the JPEG compression and the general image processing just like blurring, sharpening and gaussian noise.

• The Journal of Art Theory & Practice
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• no.7
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• pp.165-188
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• 2009

In the development of linear perspective, Brook Taylor's theory has achieved a special position. With his method described in Linear Perspective(1715) and New Principles of Linear Perspective(1719), the subject of linear perspective became a generalized and abstract theory rather than a practical method for painters. He is known to be the first who used the term 'vanishing point'. Although a similar concept has been used form the early stage of Renaissance linear perspective, he developed a new method of British perspective technique of measure points based on the concept of 'vanishing points'. In the 15th and 16th century linear perspective, pictorial space is considered as independent space detached from the outer world. Albertian method of linear perspective is to construct a pavement on the picture in accordance with the centric point where the centric ray of the visual pyramid strikes the picture plane. Comparison to this traditional method, Taylor established the concent of a vanishing point (and a vanishing line), namely, the point (and the line) where a line (and a plane) through the eye point parallel to the considered line (and the plane) meets the picture plane. In the traditional situation like in Albertian method, the picture plane was assumed to be vertical and the center of the picture usually corresponded with the vanishing point. On the other hand, Taylor emphasized the role of vanishing points, and as a result, his method entered the domain of projective geometry rather than Euclidean geometry. For Taylor's theory was highly abstract and difficult to apply for the practitioners, there appeared many perspective treatises based on his theory in England since 1740s. Joshua Kirby's Dr. Brook Taylor's Method of Perspective Made Easy, Both in Theory and Practice(1754) was one of the most popular treatises among these posterior writings. As a well-known painter of the 18th century English society and perspective professor of the St. Martin's Lane Academy, Kirby tried to bridge the gap between the practice of the artists and the mathematical theory of Taylor. Trying to ease the common readers into Taylor's method, Kirby somehow abbreviated and even omitted several crucial parts of Taylor's ideas, especially concerning to the inverse problems of perspective projection. Taylor's theory and Kirby's handbook reveal us that the development of linear perspective in European society entered a transitional phase in the 18th century. In the European tradition, linear perspective means a representational system to indicated the three-dimensional nature of space and the image of objects on the two-dimensional surface, using the central projection method. However, Taylor and following scholars converted linear perspective as a complete mathematical and abstract theory. Such a development was also due to concern and interest of contemporary artists toward new visions of infinite space and kaleidoscopic phenomena of visual perception.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.867-879
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• 2006

This paper concerns fast and time accurate HW/SW cosimulation for MPSoC(Multi-Processor System-on-chip) architecture where multiple software and/or hardware components exist. It is becoming more and more common to use MPSoC architecture to design complex embedded systems. In cosimulation of such architecture, as the number of the component simulators participating in the cosimulation increases, the time synchronization overhead among simulators increases, thereby resulting in low overall cosimulation performance. Although SystemC cosimulation frameworks show high cosimulation performance, it is in inverse proportion to the number of simulators. In this paper, we extend the novel technique, called virtual synchronization, which boosts cosimulation speed by reducing time synchronization overhead: (1) SystemC simulation is supported seamlessly in the virtual synchronization framework without requiring the modification on SystemC kernel (2) Parallel execution of component simulators with virtual synchronization is supported. We compared the performance and accuracy of the proposed parallel SystemC cosimulation framework with MaxSim, a well-known commercial SystemC cosimulation framework, and the proposed one showed 11 times faster performance for H.263 decoder example, while the accuracy was maintained below 5%.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.409-416
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• 2012

In this study, an electrical resistivity survey and a drilling investigation were conducted at an animal carcass disposal site. Chemical analysis of leachate collected from the site was also performed (sampling times: May 2011 and June 2012). Five lines of dipole-dipole electrical resistivity surveys were carried out, along with drilling investigations at 3 points within the disposal areas and 11 points near the disposal site. Two-dimensional inverse modeling of the collected resistivity data was performed to evaluate the properties (size, depth, and form) of the disposal site. Leachate analysis showed that pH of leachate decreased from 7.4 to 6.7, while Eh changed from -358 mV to -48 mV over time. In addition, dissolved ions increased due to the progression of carcass decomposition. Results of the electrical resistivity survey indicated that low resistivity zones (minimum value, $0.64{\Omega}m$) existed at a depth of 8 m from the surface. Considering the bedrock location and carcass disposal depth, there was no evidence of bedrock contamination by leachate. The results of the electrical resistivity survey are consistent with those of the drilling investigation, which indicates that electrical resistivity effectively depicted the properties of the disposal site. This study demonstrates that electrical resistivity survey is a suitable technique for investigation of animal carcass disposal sites.