• Analytical Science and Technology
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• v.34 no.5
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• pp.202-211
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• 2021

Volatile organic compounds (VOCs) in hazardous air pollutants (HAPs) have been regulated by the Air Pollution Control Act (1978) and their atmospheric concentrations have been monitored in 39 monitor sites in Korea. However, measurement standards of volatile organic compounds (VOCs) in HAPs at ambient levels have not been established in Korea. Primary reference gas mixtures (measurement standards) at ambient levels are required for accurately monitoring atmospheric VOCs in HAPs and managing their emissions. In this study, primary reference gas mixtures (PRMs) at 5 nmol/mol were developed in order to establish primary national standards of VOCs in HAPs at ambient levels. Primary reference gas mixtures (PRMs) were prepared in pressurized aluminum cylinders with special internal surface treatment using gravimetric method. Analytical methods using gas chromatography-flame ionization detector (GC-FID) coupled with a cryogenic preconcentrator were also developed to verify the consistency of gravimetrically prepared HAP VOCs PRMs. Three different columns installed in the GC-FID were evaluated and compared for the retention times and separation of eighteen target components in a chromatogram. Results show that the HAP VOCs PRMs at 5 nmol/mol were consistent within a relative expanded uncertainty (k=2) of less than 3 % except acrylonitrile (less than 6 %) and the 18 VOCs were stable for 1 year within their associated uncertainties.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1772-1776
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• 2006

The Ministry of Environment is determining reference flows and goal water qualities in many stations over all around riverbasin to control TMDL. Reference flow is now defined to 10 years averaged 275th minimum flow$(Q_{275})$. Dam operation takes direct effect on flows downstream. The Yongdam mutipurposed dam was constructed in 2002 and TMDL managing stations between the Daecheong dam and the Yongdam dam are the Geumbon B, C, D, E, and F in main stream of the Geum river. Geumbon F is the Daecheong dam site. Observed flows are ideal to be used to set reference flows, but simulated flows are more practical to be used to set reference flows from the cause of the Yongdam dam's operation. A system for simulating daily storages of the Yongdam dam was constructed and the DAWAST model was selected to simulate daily streamflows. Analysis period was selected for 10 years from 1996 to 2005. Scenario was set as follows; Firstly, observed outflows from the Yongdam dam are used from 2002 to 2005 and the Yongdam dam does not exist from 1995 to 2001. Secondly, the Yongdam dam existed also from 1995 to 2001 and simulated outflows from the Yongdam dam are used from 1996 to 2005 with provision of constant outflow of $7.0m^3/s$ and water supply to the Jeonju region outsided watershed of $900,000m^3/day$. In case of scenario 1 reference flows at the Geumbon B, C, D, E, F are 4.52, 6.69, 7.96, 11.17, and $13.21m^3/s$, respectively. And in case of scenario 2 reference flows at the Geumbon B, C, D, E, F are 6.27, 8.48, 9.58, 12.73, and $15.12m^3/s$, respectively.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.799-815
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• 2016

In this study, according to the reference setting based on the runoff video of 9:00 where the highest water level of 3.94 m has been recorded during the runoff of Cheon-mi Stream in Jeju Island by the attack of Typhoon no. 16 Sanba on September $17^{th}$, 2012, the error rate of long-distance and short-distance velocimetry and real-distance change rate by input error have been calculated and the input range value of reference point by stream has been suggested. In the reference setting process, if a long-distance reference point input error occurs, the real-distance change rate of 0.35 m in the x-axis direction and 1.35 m in y-axis direction is incurred by the subtle input error of 2~11 pixels, and if a short-distance reference point input error occurs, the real-distance change rate of 0.02 m in the x-axis direction and 0.81 m in y-axis direction is incurred by the subtle input error of 1~11 pixels. According to the long-distance reference point setting variable, the velocity error rate showed the range of fluctuation of at least 14.36% to at most 76.06%, and when calculating flux, it showed a great range of fluctuation of at least 20.48% to at most 78.81%.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.1
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• pp.83-89
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• 2023

The Korea Augmentation Satellite System (KASS) system is a Satellite Based Augmentation System (SBAS) under development to provide APV-I SBAS service in the Republic of Korea. The KASS ground segment generates correction and integrity information for GPS measurements of KASS users using the accurate positions of KASS Reference Station (KRS) antenna phase centers. For this reason, the accuracy of KRS reference points through geodetic survey campaigns is one of the important factors for providing the KASS service in compliance with the required navigation performance. In order to obtain accurate positions, two geodetic survey campaigns were performed at several reference points, such as Mark, Center of Mast at Ground Level (CMGL), and Center of Hole in Top Plate (CHTP), of each KRS site using three different survey methods, the Virtual Reference Station (VRS), Flächen Korrektur Parameter (FKP), and raw data post-processing methods. By comparing and analyzing the results, the computed coordinates of the reference points were verified and Antenna Phase Center (APC) positions were calculated using KRS Antenna Reference Point (ARP) data, and the first KASS Site Acceptance Test (SAT#1) was performed successfully using the verified APC coordinates. After the first site survey activities, the KASS operators should maintain the coordinates with the required performance such that the overall KASS navigation performance commitment is guaranteed during the lifetime of 15 years. Therefore, the maintenance plan for the KRS antenna coordinates should be developed before the commissioning of KASS operation planned after 2023. Therefore, this paper presents a geodetic survey method selected for the maintenance activities and provides the rationale for using this method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.423-428
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• 2008

The monitoring efficiency of the aircraft noise monitoring stations is decided to the reference noise level and the infringement of each monitoring stations. We are calculate the monitoring efficiency of three noise monitoring stations among twelve in the vicinity of Gimpo Int'l Airport. As a result, the monitoring efficiency shows that the noise monitoring stations #3,#5 and #6 are 14.3%, 18.5% and 29.3% respectively, #6 which is underneath the flight track is higher efficiency than another two stations.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.194-197
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• 2007

This paper proposes a linearization technique for the 3 level NPC type inverter, which increases the linear control range of inverter up to the 6-step inverter. The overmodulation range is divided into two modes depending on the modulation index(MI), In mode I, the reference angles are derived from the Fourier series expansion of the reference voltage corresponds to the MI. In mode II, the holding angles are also derived in the same way. Therefore, it is possible to obtain the linear control and the maximized utilization of PWM inverter output voltage.

• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.45-51
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• 1976

Hematological studies were conducted in reference to the immune enhancing mechanism of formalin applied to, as an inactivating agent, a formalin inactivaed anthrax vaccines in rabbits. Rabbits were inoculated two types of formalinized anthrax immunogens namely capsular and spore vaccines in addition of formalin saline as a control. From immune rabbits, peripheral blood was collected and subjected to count a total erythrocytes, leukocytes, and pyroninophilic lymphocytes. The experimental results were summarized as followings. At a level of 0.5M 0.5ml formalin with or without the addition to vaccine, a total leukocytes count was increased. Due to the increased lymphocytes, the ratio of neutrophil and lymphocyte was lowered within 4 to 12 hours of the postinoculation. Formalin saline, anthrax spore vaccine and capsular vaccine, without group difference, caused an increased level of pyroninophilic lymphocytes in peripheral blood. Throughout the studies, a possible role of immune enhancement by formlin was disscused and suggested.

• Journal of Korean Society for Quality Management
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• v.36 no.4
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• pp.87-92
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• 2008

It is common to use CUSUM charts for detecting small level shifts in processes control, in which reference value(k) and decision interval(h) are the design parameters to be determined. To control process with autocorrelation, CUSUM charts could be applied to residuals obtained from fitting ARIMA models. However, constant level shifts in processes lead to varying mean shifts in residual processes and thus standard CUSUM charts may need to be modified. In this paper, we study the performance of CUSUM charts with various design parameters applied to autocorrelated processes, especially focussing on ARMA(1,1) models, and propose how they can be determined to get better performance in terms of the average run length.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.193-197
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• 1987

Decentralized model reference adaptive controller is used to control interconnected system. Influences caused by interactions between each subsystem are regarded as unmodeled dynamics or disturbances, thus decentralized adaptive controller is designed using MRAC algorithms which guarantees robustness. To expand the stability regions of over all system and to improve control performances, higher level controller is introduced to adjust the control factors such as filter band, size of deadzone or maximum norm of parameter. Local controllers for each subsystem are realized in real time and higher level controller has an ability of detecting the instability phenomena and adjusts the local controller by analysis of power spectrum or square sum of tracking errors.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1131-1134
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• 2005

정보보호를 위해 네트워크 수준에서의 침입탐지 시스템이나 방화벽 시스템을 사용한다. 그러나 외부에서의 공격을 네트워크 수준에서 미처 대비하지 못하였을 경우에는 각 호스트들은 무방비 상태이므로 공격받을 경우 침형적인 피해를 입을 수 있다. 이러한 피해를 막기 위해서는 운영체제단에서의 대비가 필요하다. 이에 본 논문에서는 보안 운영체제 연구에 대한 동향을 살펴보고, MLS(Multi Level Security)정책을 사용하는 보안 운영체제에서 보안등급이 서로 다른 주체와 객체의 긴급접근이 이루어져야 할 때, 기존 MLS의 참조모니터(Reference Monitor)를 개선시켜 접근을 해결하는 방안을 제시했다.