• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.6
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• pp.521-530
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• 2016

Weather radar is observation equipment that transmits electromagnetic waves and receives backscattered signals from the targets. The weather radar systems of the Korea Meteorological Administration have a doppler mode that can extract the target's radial velocity. However, the radial velocity over the maximum unambiguous velocity(${\nu}_m$) for which is in a trade-off relationship with the maximum unambiguous range is folded. Therefore, a dual PRF mode of which transmits and receives signals using two different PRFs(high and low) must be used to extend the vm while maintaining the maximum unambiguous range. Using a dual PRF mode, vm can be extended to the amount of lowest common denominator of two observed vm from high and low PRF. For this extension, we have developed a velocity unfolding algorithm of which uses several criteria for classification considering observed velocity differences between high and low PRF and their error boundary. Then, correction factors are calculated for each class and are applied to unfold radial velocity. The developed algorithm was applied to the Yong-In Testbed(YIT) radar and the generated better performance of radial velocity extraction than those of the previous system.

• Journal of Life Science
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• v.19 no.7
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• pp.968-975
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• 2009

The purpose of the present study was to examine effects of different exercise training modes (Aerobic Training, Resistance Training) on exercise specificity and transability. The tested subjects, composed of 10 healthy males without known family history or medical illnesses, were divided into two groups: Aerobic Training Group (ATG; n=5) and Resistance Training Group (RTG; n=5). An aerobic training program, based on maximum oxygen consumption rates taken during standard testing, was conducted in 60 minute sessions 3 times a week, and the Heart Rate Reserve (HRR) at 70% of maximum oxygen consumption rate was measured the using Polar. In the weight training program, based on repetition maximum rate (1-RM) taken during standard testing, the weight at 70% of such rates was measured during 60 minute sessions of 7 categories of exercise (Bench press, Leg press, Squat, Shoulder press, Arm curt Lat pull down, Triceps pull down), conducted 3 times a week. The data collected from this research were calculated to obtain average and differences compared to standards using an SPSS 11.0 statistics package. In conclusion, increase in V0$_{2max}$ and production of NO$_x$ (NO$_2$/NO$_3$), reduction of %fat, MAPwere shown effective in aerobic training and in different exercise tests, and aerobic testing within the aerobic training group (ATG) was shown to be more effective. In contrast, resistance training was shown to be more effective for the reduction of CK and LDH, and even in different tests, the resistance test within the resistance training group (RTG) showed to be more effective. Exercise specificity also significantly increased in both groups (ATG, RTG). but there was no significant difference in transability in both groups (ATG, RTG).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.354-354
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• 2009

We have developed the prototypes of superconducting magnetic separation system with high temperature superconductor wire. This separation filter system consist of magnetized matrix SUS430 wire and acrylic frame. This study introduced rolled steel process coolant wastewater applied superconductor HGMS(High Gradient Magnetic Separation). HGMS treatment have acted high efficient method for various wastewater. We have surveyed superconducting magnetic separation technology and reviewed the status of related industries using applied superconductivity. In our basic preliminary experiment using HGMS, it was made clear that the fine para-magnetic particles in the wastewater obtained from rolling process of steel can be separated with high efficiency. We investigated the ability of magnetic flock formation, which used inorganic materials and polymer coagulants. We had a purpose to remove SS of coolant at steel factory. Maximum coagulation remove rate of SS 98%. Removing ratio of $Fe_3O_4$ fine particles in wastewater showed over than 99% in the wastewater containing magnetic fines after four times of repetition of separation.

• Journal of the Korea Computer Industry Society
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• v.6 no.2
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• pp.357-364
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• 2005

The prefabricated type used generally in Korea to join cable runs on new installations or to repair broken Cable runs on existing installations, because installation is very simple and save time. This type is a permanent, shielded and submersible cable joint for direct burial or vault application. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Faults arise from impurities or voids. A suitable solution for a monitoring of cable joints during the after-laying test and service is partial discharge detection. Specimen obtained 1mm thickness from the insulation of real power cable and cable joint. <중략>The partial discharges are measured to determine their time dependence for 60 minutes and the influence of applied electrical stress under 30kV. $\Phi-q-n$ properties were measured using detection impedance, high pass filter and computerized data acquisition system. Statistic Value like maximum charge, repetition rate, average charge, etc. are calculated. It is possible to quantitative analysis of $\Phi-q-n$ properties from this statistic value and pattern analysis.

• Journal of the Korea Computer Industry Society
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• v.6 no.2
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• pp.279-286
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• 2005

The prefabricated type used generally in Korea to join cable runs on new installations or to repair broken Cable runs on existing installations, because installation is very simple and save time. This type is a permanent, shielded and submersible cable joint for direct burial or vault application. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Faults arise from impurities or voids. A suitable solution for a monitoring of cable joints during the after-laying test and service is partial discharge detection. <중략> $\Phi-q-n$ properties were measured using detection impedance, high pass filter and computerized data acquisition system. Statistic Value like maximum charge, repetition rate, average charge, etc. are calculated. It is possible to quantitative analysis of $\Phi-q-n$ properties from this statistic value and pattern analysis.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.79-86
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• 1995

The structural materials for cryogenic technology have been recently developed to support the many modern large-scale application from superconducting magnets for nuclear fusion reactor, magnetic levitation railway to LNG tankers. However it is pointed out that quenching phenomenon is one of the serious problems for the integrity of these applications, which is mainly attributed to the rapid temperature rising in the material due to some extrinsic factors of structures. From the viewpoint of fracture mechanics, it is therefore very important to clarify the mechanism of temperature rising of structural material due to cyclic loading at cryogenic temperature. From this purpose, fatigue test was carried out for high manganese steel at liquid helium temperature(4.2K) using triangular stress waveform to identify both the mechanism of temperature rising near crack tip and the effect of loading stress waveform on temperature rising near crack tip and the effect of loading stress waveforms on temperature rising. As the results, two types of temperature rising, that is, regular and burst types were observed. And a periodical temperature rising corresponding to the stress waveforms was also found. The peaks of the temperature rising were recorded near both the maximum and the minimum values of the applied stress. The sudden temperature rises, which indicated the higher values than those of periodical temperature rises under the repetition of stress, were observed at the final region of crack growth. It was shown that the peak values of the temperature rising increased with stress intensity factor range.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1651-1658
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• 2002

Recently power cable used generally in Korea, because installation is very simple and it has high stability. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Especially, fault rates are arise from impurities or voids. A suitable solution for a monitoring of power cable during the after-laying test and service is partial discharge detection. The artificial defects between cable joint(EPR) and insulator(XLPE) interface are considered in this research to investigating the partial discharge characteristics. ${\varphi}$-q-n properties were detected using data acquisition system and Maximum charge($q_{max}$), repetition rate(${\={n}$), average charge(${\={q}$), Unbalance rate of ${\={n}$ and ${\={q}$ are calculated in order to analysis partial discharge properties quantitatively from this statistic value.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.75-80
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• 2013

In this paper, the Ka-band maritime satellite communication systems for mobile terminals are proposed. The design includes the link budget analysis, determination of modulation and coding schemes and the overall structure of a transmitter. To avoid the harmful effects on the existing DVB-S2 services, the proposed maritime satellite system using the same spectrum with DVB-S2 at the same time employs the very wideband spreading transmission. Additionally, omni-directional low-gain antennas should be equipped in a mobile terminal to reduce the system cost. These two considerations limit the maximum transmission rate of the proposed system. Due to the limitations, the proposed system includes 36 dB or 39 dB spreading gain depending on the modulation scheme and a link-adaptive repetition method depending on the level of rain attenuation. To support short packets with minimal performance loss, the turbo code used in 3GPP instead of LDPC(low density parity check code) is adopted. By combining them, the overall structure of low-rate maritime satellite communication system is designed.

• Korean Journal of Child Studies
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• v.3
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• pp.83-96
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• 1982

TV has a very strong influence on various aspects of children's life and development. In view of this influence, various problems related to the content and production of TV programs for early - childhood deserve a careful study. Recognizant of this significance, this study aims to suggest the direction in which the production of TV programs for early childhood in Korea will steer by defining the concept of TV programs for early childhood and by analyzing the current status and trends of producting TV program for early childhood at abroad. In this study, attempts were made to suggest some strategies for the production of TV programs for early childhood based on an expansive literature review. 1. The running time of TV programs for early-childhood ages of 4-5 year old is suggested to be 15 minutes. 2. In the process of producing the programs, a group of professionals including in-service teachers, researchers specializing in child development, psychology and sociology, idea-creators, script writers, media experts, producers, and monitors should provide concerted efforts throughout the process. 3. The running time of TV programs for early-childhood should be less than 20 minutes and therefore should have simple learning objectives. 4. The contents of programs should be organized in such a way as to enable children to view themselves as well as the environment in more positive ways and to fester desirable values and beliefs in them based on various constructive activities and plays. 5. The programs should adopt various techniques including repetition, to ensure the maximum learning effect in full consideration of children's interest. 6. The programs should be continuously revised and supplemented based on the evaluation of the programs, children's responses and monitor's feedbacks.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.34-39
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• 2016

Objective: Hip abductors play a role in providing stability and movement to the lower limbs. The purpose of this study was to examine the effects of hip abductor fatigue on static balance and gait in the general population. Design: One group pre-test post-test design. Methods: Thirteen university students in their twenties volunteered for the study and had underwent a functional assessment. To induce fatigue, the subjects were instructed to raise their dominant lower extremity up against a load of 50% of 1 repetition maximum while producing hip abduction in a side-lying position. Subjects were instructed to maintain an abduction speed of 30 repetitions per minute to induce fatigue. Muscle fatigue was considered to be established when subjects were unable to perform hip abduction three consecutive times along with the metronome. A post-test of balance and gait was performed immediately in order to prevent fatigue recovery. The center of pressure (COP) distance area was measured using the Zebris FDM-S Multifunction Force measuring plate. Gait performance was analyzed using the GAITRite. Results: The COP distance was increased after fatigue was induced. There was a significant increase in the standard deviation of the medio-lateral and antero-posteror distance (p<0.05). Although there was no significant difference in gait parameters, there was a significant decrease in single support time after fatigue was induced (p<0.05). Conclusions: There was an increase in static balance instability and a significant decrease in single support time during gait due to hip abductor muscle fatigue.