• Progress in Superconductivity
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• v.13 no.1
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• pp.1-6
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• 2011

Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.215-219
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• 2004

In this study, Types of irrigation water development in islands district were classified. The types were reservior, fleshwater lake, pumped storage, etc. Most of islands district has delveloped reuse irrigation system as a pumped storage system. But. Irrigation water-reuse ratio doesn't define a basis clearly and the value of measurement for water-reuse ratio doesn't exist so far. so, we measured Irrigation water-reuse to clarify for water-reuse ratio in a pumped storage system. Also, we need to develop hydrologic analysis and water balance method with characteristic factor of islands district. that make use of plan about security of agriculture water efficiently in islands district.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.622-627
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• 2002

The power comparison techniques have implemented power measurements, in which a power comparator is used to balance ac against a dc power obtained from known values. The developed power standard system using the comparison techniques consists of dc sources, ac source, control switches, resistive voltage dividers, resistive shunts and a power comparator. The total uncertainty of the power standard system was proved by analysis of the component instruments. Its expanded(k=2) uncertainty is evaluated to be less than 30 uW/VA at unit power factor and 42 uW/VA at power factor 0.5

• Journal of Mechanical Science and Technology
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• v.16 no.9
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• pp.1121-1136
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• 2002

The flow characteristics of film coolant issuing into turbulent boundary layer developing on a convex surface have been investigated by means of flow visualization and three-dimensional velocity measurement. The Schlieren optical system with a spark light source was adopted to visualize the jet trajectory injected at 35° and 90° inclination angles. A five-hole directional pressure probe was used to measure three-dimensional mean velocity components at the injection angle of 35°. Flow visualization shows that at the 90° injection, the jet flow is greatly changed near the jet exit due to strong interaction with the crossflow. On the other hand, the balance between radial pressure gradient and centrifugal force plays an important role to govern the jet flow at the 35° injection. The velocity measurement shows that at a velocity ratio of 0.5, the curvature stabilizes downstream flow, which results in weakening of the bound vortex structure. However, the injectant flow is separated from the convex wall gradually, and the bound vortex maintains its structure far downstream at a velocity ratio of 1.98 with two pairs of counter rotating vortices.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2037-2042
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• 2011

The railway electromagnetic environment is much more severe than most commercial and domestic environments. There are concerns about electromagnetic emissions from railways and their potential to interfere with the operation of commercial radio service and other equipment. EMC standards for railway applications are referenced as EN 50121 series and these standards describe the measurement method and specify limits for emission. However standard provide precise description of the general aspect of the measurement procedure and requirement of test equipments, making a reliable measurement of the radiated emissions from a train is a problem of balance between available observation time and the measurement time required by the characteristics of the measurement system. This paper focuses on the problem of measurement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.723-728
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• 2003

The physical restoration technology for lower limb amputees is being advanced as the biomechatronics is being applied to the area of rehabilitation. As the advanced prosthetics for lower limb amputees are introduced, a suitable prescription of biomechanical rehabilitation training becomes important to utilize the advanced full features of the devices. Since lower limb amputation significantly affects biomechanical balance of mosculoskeletal system for gait, an appropriate and optimal biomechanical training and exercise should be provided to rebalance the system before wearing the prostheses. Particularly, biomechanical muscular training for hip movements in the both affected and sound lower limbs is important to achieve a normal-like ambulation. However, there is no study to understand the effect of hip muscle strength on the gait performance of lower limb amputees. To understand the hip muscle strength characteristics for normal and amputated subjects, the isokinetic exercises for various ratios of concentric contraction to eccentric contraction were performed for hip flexion-extension and adduction-abduction. As a results. biomechanical isokinetic training protocols and performance measurement methodologies for lower limb amputees were developed in this study. Using the protocols and measurement methods, it has been understood that the appropriate and optimal biomechanical prescription for the rehabilitation process for lower limb amputees is important for restoring their gait ability

• Journal of Power System Engineering
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• v.3 no.3
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• pp.44-53
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• 1999

This study is concerned with the emission characteristics of kerosene fan heater, which is burned with kerosene and water droplets simultaneously in the burner, in order to prohibit the emissions of harmful exhaust gas and reduce smell caused by incomplete combustion, and the addition of water droplets to the conventional kerosene fan heater was performed by ultrasonic atomizer. For the investigation of this study, the measurement of exhaust gas components and exhaust gas temperature was carried out by using an automatic combustion gas analyser and $NO_x$ analyser, and the measurement of consumption weight of oil and water was obtained by using electric digital balance. Consequently, according as the water percent weight ratio of about $21{\sim}23%$ was supplied for this study, it was found that the combustion-generated $NO_x$ and CO emissions were reduced very largely, but the emissions of $O_2\;and\;CO_2$ and the temperature of exhaust gas were not changed.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.117-124
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• 2011

This study was realized the home network system for home care by bio-physical sensor system, to convey for the remote physical signal. The composition condition has four functions of displacement point for a Vision, Somatosensory, Vestibular and CNS that the basic measurement used to a Heart Rate, Temperature, Weight. Physical signal are decided to search a max and min point with adjustment of 0.01 unit in the reference level. There were checked physical condition of body balance to compounded a physical neuroceptor of sensory organ for the measurement such as a Vision, Somatosensory, Vestibular, CNS, BMI. There are to check a health care condition through a combination of physical organ with a posturography of a exercise. The service of home network system can be used to support health care management system through health assistants in health care center and central health care system. It was expected to monitor a physical parameter for the remote control health management system.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.705-713
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• 2003

In mid-August 2002, under clear summer pressure patterns, we carried out an intensive meteorological observation to examine the warming effects due to artificial constructions in a large housing complex. We set an automatic weather system(AWS) at two places in a bare soil surface within a limited development district and an asphalt surface within a large apartment residence area, respectively. As a result of observation, it became clear that the difference of the surface air(ground) temperature between the bare soil surface and its peripheral asphalt area reached about 4$^{\circ}C$(13$^{\circ}C$) at the maximum from diurnal variation of surface temperatures on AWS data. Through the heat balance analysis using measurement data, it became clear that the thermal conditions at two places are dependent on the properties of surface material. The latent heat flux over the bare soil surface reached to about 300 W/㎡, which is more than a half of net radiation during the daytime. On the other hand, it was nearly zero over the asphalt surface. Hence, the sensible heat flux over the asphalt surface was far more than that of the bare soil surface. The sensible heat flux over the asphalt surface showed about 20∼30 W/㎡ during the night. It was released from asphalt surface which have far more heat capacity than that of bare soil surface.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.5
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• pp.359-366
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• 2015

TMJ(TemporoMandibular Joint) is considered as the most important articulation in human body for maintaining the balance. Thus it is one of the main treatment areas in Chiropractic. Instead of Chiropractic treatment, NOSICK, a TMJ balancing device, can be used. As there is no such device to quantify the effect of NOSICK, a system was developed to measure the effect of NOSICK. This system is composed of stereo vision, infrared lights, and infrared through filter, etc. It requires optical markers for the measurement. 8 land markers were selected from the face which will show different displacement as NOSICK is applied. 11 test subjects were measured with the system developed with and without NOSICK applied. Quantifiable displacement of markers before and after applying NOSICK was successfully measured with the system developed.