• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.882-890
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• 2009

In this paper, we describe a compensation method that can be used for the situation where Loran receivers lose their phase lock to the received Loran signals when Loran signals are employed for the synchronization of national infrastructures such as telecommunication networks, electric power distribution and so on. In losing the phase lock to the received signals in a Loran receiver, the inner oscillator of the receiver starts free-running and the performance of the timing synchronization signals which are locked to the oscillator's phase is very severly degraded, so the timing accuracy under 1 us for a Primary Reference Clock (PRC) required in the International Telecommunications Union (ITU) G.811 standard can not be satisfied in the situation. Therefore, in this paper, we propose a method which can compensate the phase jump by using a compensation algorithm when a Loran receiver loses its phase lock and the performance evaluation of the proposed algorithm is achieved by the Maximum Time Interval Error (MTIE) of the measured data. From the performance evaluation results, it is observed that the requirement under 1 us for a PRC can be easily achieved by using the proposed algorithm showing about 0.6 us with under 30 minutes mean interval of smoothing with 1 hour period when the loss of phase lock occurs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3330-3335
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• 2010

Due to the acceleration of medical information age, the semantic interoperability of clinical information is rising up as a major issue. The laboratory results are known as the best significant area among clinical information to be required for exchanging and sharing. The aim of this research is to develop the clinical contents model for exchange laboratory results. This research was conducted from March 2008 to September 2008. Firstly, the method is to get the attributes and codes from LOINC which is one of the standard medical terminology system related to laboratory and the Reference Information Model(RIM) of Health Level 7(HL7). Secondly, the attributes from each work process around orders and reports of laboratory was analyzed. We evaluated the attributes whether they could be represented into the attributes contained in HL7's RIM. Thirdly, the prototype for hemoglobin case using the structure of clinical contents model and defined attribute. Fourthly, the face validity was done by one laboratory physician with four clinicians. The assessment contents were for the suitability involved in representation and exchange with proposed model. The results shows that the model corresponds with the aim of the research. Eventually the proposed model for the exchange of laboratory results could contributes to information interchange according to laboratory area for the future.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.146-154
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• 2001

This research was conducted to investigate the seasonal changes in physicochemical characteristics of stream water at the four points in the northeastern part of the Puk'ansan National Park from July of 1998 to November of 2000. The average pH of stream water was 6.6(6.53~6.74) and the dissolved oxygen was ranged from 11.0 to $11.3mg/{\ell}$, which indicated that the water quality could be categorized in the first class for the quality of river water quality standard. The average electrical conductivity of stream water was 106.8(52.3~154.0) ${\mu}S/cm$ and the electrical conductivities of downstream water were ranged from 139.4 to $154{\mu}S/cm$, which were about 1.7~3.0 times higher than those in upstream water that showed from 52.3 to $81.6{\mu}S/cm$. The amount of anion($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) which indicates the pollution index in downstream was higher than that in upstream, In addition, the seasonal impacts of pollution on stream water were higher in Autumn than in Spring or Summer.

• Journal of Korean Society of Steel Construction
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• v.22 no.5
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• pp.399-409
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• 2010

Steel structures are threatened to reduce load-carrying capacity as the cross section is decreased by corrosion. However, there has been no method in definitely evaluating residual load-carrying capacity and the effect of corrosion to the load-carrying capacity of steel. This study evaluated tensile residual load-carrying capacity of corroded steel plates by using tensile tests of specimens, which were selected from the web of temporary structure's main beam. After the surface shapes were measured and tensile tests were examined, the rust of 21 corroded specimens was, first of all, removed using a chemical method. From the tensile test result, which of reference specimens that was picked off at the flange of the same main 13-mm-thick beam and corroded specimens were based, surface geometry and correlation with the reduction of corroded thickness and strain, yield strength or tensile strength was established as constant numbers. Effective thickness of corroded steel with irregular cross sections could be calculated using average residual thickness and standard deviation. The irregular cross sections could be the evaluated tensile strength that is equalized to non-corroded uniform steel's regardless of corrosion. Also, reasonable measuring intervals of residual thickness could be proposed by using this result to apply for executive work.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.1-6
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• 2019

In this study, the development of a weight estimation model of electronic scale with nonlinear characteristics is presented using polynomial regression analysis. The output voltage of the load cell was measured directly using the reference mass. And a polynomial regression model was obtained using the matrix and curve fitting function of MS Office Excel. The weight was measured in 100g units using a load cell electronic scale measuring up to 5kg and the polynomial regression model was obtained. The error was calculated for simple($1^{st}$), $2^{nd}$ and $3^{rd}$ order polynomial regression. To analyze the suitability of the regression function for each model, the coefficient of determination was presented to indicate the correlation between the estimated mass and the measured data. Using the third order polynomial model proposed here, a very accurate model was obtained with a standard deviation of 10g and the determinant coefficient of 1.0. Based on the theory of multi regression model presented here, it can be used in various statistical researches such as weather forecast, new drug development and economic indicators analysis using logistic regression analysis, which has been widely used in artificial intelligence fields.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.496-502
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• 2015

Hydrocarbon dew point(HCDP), a property which is the most generally used for describing natural gas condensation, is a very important parameter of natural gas quality specifications. HCDP is strongly influenced by the concentration of the heavier hydrocarbon components, especially $C_6+$, so, along with compliance with gas quality specifications, build up of procedures for obtaining accurate HCDP is essential for gas transmission company, because hydrocarbon condensation present may cause serious operational and safety problems. This study has been carried out in an attempt to measure HCDP accurately by the automatic hydrocarbon dew point meter under the actual field conditions. Measured HCDP also has been compared with calculated HCDP using the composition determined by gas chromatograph and industry accepted equation of state at multiple pressures, along with the cricondentherm. The test results are 1) the automatic hydrocarbon dew point meter was able to measure stable HCDP continuously 2) the automatic hydrocarbon dew point meter has been performed reference measurement by pure propane with a known dew point from literature, and 3) A meaningful differences was observed when comparing the automatic hydrocarbon dew point meter and gas chromatograph results for synthetic standard gas mixtures and real gas mixtures.

• The Journal of Korean Physical Therapy
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• v.17 no.3
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• pp.329-338
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• 2005

The determination of peripheral nerve conduction velocity is an important part to electrodiagnosis. Its value as neurophysiologic investigative procedure has been known for many years but normal value of digital nerve was not reported in Korea. To evaluate of digital nerve conduction velocity of median nerve for obtain clinically useful reference value and compare difference in each fingers. 71 normal volunteers(age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II was use for detected conduction velocity and amplitude of digital nerves in median nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation, ANOVA was used to compare each fingers and independent t-test was used to compare between Rt and Lt side also compare between different in genders. Conduction velocity of the right thumb was 49.77m/sec, index finger was 56.80m/sec, middle finger was 56.15m/sec and ring finger was 53.38m/sec. The left thumb was 50.48m/sec, index finger was 56.76m/sec, middle finger was 55.99m/sec and ring finger was 53.23m/sec. Amplitude of the right thumb was $64.30{\mu}V$, index finger was $73.95{\mu}V$, middle finger was $77.97{\mu}V$ and ring finger was $43.92{\mu}V$. The left thumb was $74.21{\mu}V$, index finger was $85.72{\mu}V$, middle finger was $88.06{\mu}V$ and ring finger was $47.28{\mu}V$. There were significantly difference between thumb, index, middle and ring fingers(p<.01) but there were no statistically difference between conduction velocity and amplitude of index and middle fingers(p>.01). The conduction velocity of index finger are faster than other fingers and amplitude of middle finger are greater than other fingers. The present results revealed that electodiagnosis can easily perform in index and middle finger for digital nerve of median nerve study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.191-200
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• 2020

Tracked military vehicles are operated under harsher conditions and climates than ordinary vehicles, and the components require high degrees of reliability and durability. A diesel engine is the main power generator, and when the vehicle breaks down, there is a high possibility of causing a large-scale accident. Therefore, analyzing the cause of engine failure can be important for preventing similar cases that may occur. In this study, we clarified the mechanism of engine failure according to an overhaul test, hardness measurement, and an analysis of the fracture surface. The overhaul test confirmed that a bolt was separated from the connecting rod (number 4). In addition, the hardness measurement results of the connecting rod bolt conformed to the standard, and it was found that the bolt fracture was ductile fracture through an analysis of the fracture surface. Based on the results, it was concluded that damage to a diesel engine of a tracked military vehicle was caused by separating and damage caused by loosening of the connecting rod bolts, resulting in cascading damage. The results of the study could be used as reference examples and could be useful for another study on engine failure analysis.

• Analytical Science and Technology
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• v.14 no.2
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• pp.131-139
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• 2001

There is personal difference in the concentrations of trace elements in human hair according to human life or history suck as occupation, race, sex, age, food habit, social condition and so on. It is also found that the individual's deviation of elemental concentrations is reflecting the degree of environmental pollutants exposure to human body, intakes of food and metabolism. To compare the degree of accumulation in the hair tissue, human hair samples were collected from five positions of head and analyzed by non-destructive neutron activation analysis with and without washing according to IAEA's recommended method. Analytical quality control is performed using the certified reference material. The relative error of Cu, Cr, Na, Co, Mg, As, Se, Zn and those of Mn, Ca, Fe, Sr are within ${\pm}5%$ and ${\pm}10%$, respectively and the relative standard deviation of elements are within ${\pm}10%$. The deviations between the individuals and hair sampling positions were estimated. The deviation of individual was seven times more than that of positions. Under the defined condition, the difference and the correlation of elemental concentrations were compared with two different groups, office and factory workers. The result can be used as a fundamental data for human health and environment assessment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.382-390
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• 2017

In this paper, we consider particular exposure scenarios to evaluate human effects for inductive commercial wireless charging device operating at low frequency. The coil used in this study is the A10 model in Qi standard proposed by WPC(Wireless Power Consortium), and input power is 5 W to the operating frequency of 155 kHz. In perfectly aligned condition, the max leakage magnetic field is $257.58{\mu}T$ which is obtained at the side of the device, and it is exceeded about 7.4 times of the ICNIRP 1998 reference level. The SAR is evaluated with homogeneous phantom which has electric constants of wet skin. The max value of the SAR is $134.47{\mu}W/kg$ which is obtained at the side of the device also, and it is much lower than the international guidelines. Especially, it showed higher SAR values in case of misalignment condition, so we will need to consider the misalignment condition importantly when we evaluate human effects for wireless power transfer system.