• Proceedings of the KSRS Conference
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• v.1
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• pp.39-42
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• 2006

The paper reports on the first experimental evidence for space-observed manifestation of the open ocean tsunami in the microwave radar backscatter (in C- and Ku-bands). Significant variations of the radar cross section synchronous with the sea level anomaly were found in the geophysical data record of the altimetry satellite Jason-1 for the track which crossed the head wave of the catastrophic tsunami of 26 December 2004. The simultaneous analysis of the available complementary data provided by the satellite three-channel radiometer enabled us to exclude meteorological factors as possible causes of the observed signal modulation. A possible physical mechanism of modulation of short wind waves due to transformation of the thin boundary layer in the air by a tsunami wave is discussed. The results open new possibilities of monitoring tsunamis from space..

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.269-276
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• 2004

A marine diesel engine should realize optimal efficiency operation while reducing NOx. Fuel injection systems by electronic control can become effective means for that. Although it would be able to get more precise engine control compared to the mechanical injection system, it needs some accurate and instant information in order to bring its ability into full play while sailing on the sea. Very important information of them is shaft torque and continuous combustion pressure of all cylinders. The system presented in this report can deliver those data.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.493-495
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• 2007

Future sub-meter resolution LEO missions require simultaneous dual-polarization downlink and/or multiple channel downlinks in single polarization. Especially, dual-polarization is needed to cope with bandwidth limitation due to high speed data transmission. Current KARI 13m X-Band antenna system needs to be upgraded to cope with such downlink schemes. This paper describes brief discussions on engineering work regarding how to meet the new requirements with minimum impact on current system as well as C&M (Control and Monitoring) software.

• Journal of Food Hygiene and Safety
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• v.14 no.2
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• pp.140-145
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• 1999

Analytical method for preservatives in food was developed using gas chromatography/mass spectrometry (GC/MS). Propionic acid, sorbic acid, benzoic acid, ethyl salicylate, ethyl p-hydroxy benzoate, iso-propyl p-hydroxy benzoate, n-propyl p-hydroxy benzoate, iso-butyl p-hydroxy benzoate, n-butyl p-hydroxy benzoate, p-hydroxy benzoic acid and dehydro acetic acid were extracted from cooling beverage with diethyl ether. The polar hydroxyl and carboxyl groups of food preservatives were derivatized with N-methyl-N-tert-butyldimethylisilyl-trifluoroscetamide (MTBSTFA) to form the corresponding tert-bytyldimethyl-silylated derivatives, and submitted to GC/MS analysis. The mass spectra of the derivatives were investigated for the selection of monitoring ions for multi-residue analysis of 11 preservatives by GC/MS. The macro program was also developed for the qualitative analysis of these preservatives in food.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.6
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• pp.475-485
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• 2002

An analytical method was investigated for the meaiiurement of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) concentrations in air samples. Procedures required for column chromatographic clean up. silicagel (stage I) and gel permeation chromatography (stage II), were discussed. Identification and quantification of PCBs and OCPs were performed using a combination of gas chromatography/mass spectrometry/ selected ion monitoring. Recovery tests calculated from six samples are 68∼137% for PCBs and 58∼130% for OCPs except for endrin aldehyde. Instrumental detection limits determined for the PCBs and OCPs varied from 0.05 to 0.18 pg/m3 and from 0.71 to 16.82 pg/㎥, respectively. The method has been applied to the analysis of air samples collected at Ansung city, Kyonggi province, Korea. This method may serve as a screening protocol for the simultaneous determination of PCBs and OCPs in air.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.111-116
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• 2006

PET/CT is a new imaging technology that combines high-quality Positron Emission Tomography (PET) and Computed Tomography (CT). This imaging provides simultaneous anatomical and metabolic information. Therefore PET/CT is useful diagnostic modality for early detection of malignant tumor, accurate staging, decision on therapeutic plan, monitoring response to therapy and rapid detection of recurrence. We report oral and maxillofacial cancers diagnosed by using PET/CT and the usefulness of PET/CT in the evaluation of postoperative recurrence.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.1
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• pp.10-19
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• 1990

A fault tolerant control system, in which a digital back-up controller system is added on the existing analog control system, is developed for enhancing reliability of boiler control system in power plant. The digital back-up controller system(DBCS) has a multi-processor structure with capabilities of fault diagnosis, back-up control, self test, and graphic monitoring. Specifically, switching mechanism composed of expandable modules is designed so that back-up controller takes over any faulty control loops and the number of back-up control loops is determined as that of simultaneous faults. A process simulator that simulates the boiler analog control system is developed for safety test and performance evaluation prior to real plant application. DBCS is installed at the Ulsan thermal power plant, and fault tolerant control performance is assured under the faults that some controller modules are pulled out.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.1
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• pp.100-108
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• 1999

Variable air volume(VAV) system designed for improving interior environmental control has steadily evolved over the last 20 years. Major advantage of VAV system is that VAV technology allows a single system to provide simultaneous heating and cooling without a seasonal changeover. Research is carried out in order to study the influence on the energy consumption and ventilation performance of two kinds of office building with a mixing ventilation system. Data required for performance evaluation in these building is obtained from the central monitoring station and by measurement.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.215-222
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• 2016

When the linear correlation of the quality variables are considerably high, multivariate control charts may be a more effective way than univariate charts which operate quality variables and process parameters individually. Performances and efficiencies of the multivariate control charts under multivariate normal process has been considered. Some numerical results are presented under small scale of the shifts in the process to see the improvement of the efficiency of EWMA chart and CUSUM chart, which use past quality information, comparing to Shewart chart, which do not use quality information. We can know that the decision of the optimum value of the smoothing constant in EWMA structure or the reference value in CUSUM structure are very important whether we adopt combine-accumulate technique or accumulate-combine technique under the given condition of process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.532-535
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• 2000

We have fabricated a sensor system for on-line monitoring the oxygen permeability and diffusivity of six different polymer films using the miniaturized 6 cathode(Ag)-single anode(Ag/AgCl) type hexagonal oxygen electrode. This system consists of multiple input front-end electronics, signal conditioning circuit using the embedded microcontroller 80C196KC, PC interface circuit and PC with the OS for microcontroller and the operating program for this system. The digital low-[ass filter was programmed and the simulated filter characteristics were enough to eliminate the noise from sensor signal. According to the experimental results, the linearity coefficients of the output voltage to oxygen partial pressure for each sensor electrode of six cathode type oxygen sensor are 0.998, 0.997, 0.998, 0.997, 0.997, 0.997 respectively, and the response times are all within 4 minutes.