• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3685-3693
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• 2021

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

• 한국수산과학회지
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• 제49권1호
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• pp.45-52
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• 2016

This experiment investigated changes in metabolic rate (MO₂), critical oxygen saturation (S_crit), and blood chemistry of olive flounder Paralichthys olivaceus exposed to progressive hypoxia and returned to normoxic water at 20°C. The normoxic standard metabolic rate (SMR) and routine metabolic rate (RMR) were 69.5-83.9 and 70.2-156.4 mg O₂ kg^-1h^-1, respectively based on fish weight. S_crit was 31.0% dissolved oxygen (DO) at 20°C. After returning the fish to 70% DO following exposure to hypoxia (20% DO), MO₂ increased two-fold compared to the normoxic SMR and then decreased into the range of the RMR with time. Blood PO₂ and plasma lactate decreased significantly after exposure to hypoxia (20% DO) and then increased as ambient oxygen saturation decreased. Cortisol levels increased as ambient oxygen saturation decreased, but the levels decreased rapidly in the range of the normoxic control when the fish were returned to ambient water with 70% DO. Plasma glucose levels increased when the fish were returned to normoxic water after exposure to a progressively more hypoxic condition.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.48.1-48.11
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• 2020

Objectives: This systematic review aimed to identify mean oxygen saturation values (SpO₂) using pulse oximetry in permanent maxillary anterior teeth. Materials and Methods: The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of "oximetry" AND "dental pulp test" were used as search terms. Studies reporting means and standard deviations of SpO₂ values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I² statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. Results: Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO₂ values were 84.94% (95% confidence interval [CI], 84.85%-85.04%) for the central incisors, 89.29% (95% CI, 89.22%-89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%-89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment. Conclusions: Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status.

• 생태와환경
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• 제38권2호통권112호
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• pp.217-224
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• 2005

본 연구는 4년에 걸쳐 조사된 팔당호 식물플랑크톤 조사자료를 토대로 각 분류군별 세포수 및 점유율 그리고 우점 조류속의 장기변동 패턴을 평가하고, 아울러 이들과 수질과의 관계를 규명해보고자 시도되었다. 규조류는 조사기간 중 비교적 지속적으로 출현하는 경향을 보였으며, 남조류는 매년 6 ${\sim}$ 9월에 집중적으로 발생하는 특징을 보였고 7월경 가장 높은 세포수를 나타냈다. 녹조류의 경우 높은 세포수를 나타내는 시기는 6 ${\sim}$ 8월로서 남조류의 경우와 유사하였다. 기타 조류는 Cryptomonas속이 거의 대부분을 차지하였으며, 5 ${\sim}$ 8월에 높은 세포수가 관찰되었다. 조사기간 중 우점속 (매년 조사기간 중 출현 세포수 총계가 평균 7,000 cells $mL^{-1}$ 이상인 것을 대상으로 함)은 Aulacoseira 및 Cyclotella속(규조류), Microcystis와 Anabaena속 (남조류), Scenedesmus속 (녹조류) 그리고 Cryptomonas속 (은편모조류) 이었다. 각 분류군별 세포수와 수질조사 자료 간의 상관관계는 낮은 수준을 보였으며, 유의성이 있는 것 (p<0.05)으로 나타난 항목 중 상관계수 0.3 이상을 나타낸 분류군은 규조류의 경우 수온과 총인, 남조류는 수온, pH, DO포화도, COD, 총인, 녹조류는 수온, pH, DO포화도, COD, SS, 총인이었다. 속(genera)별 상관계수 0.3 이상을 나타낸 것은 Aulacoseira속의 경우 총질소와 총인, Anabaena속은 수온, DO포화도, COD, 총인, Microcystis속은 수온, pH, DO포화도, 총인, Coelastrum속은 COD와 SS, Scenedesmus속은 수온, COD, 총질소, 총인, Cryptomonas속은 DO포화도와 총질소였다. 팔당호에서의 남조류 bloom에는 유입량에 의한 1차적인 영향을 제외하면, 수온조건이 인 농도 증가에 의한 영향보다 더 크게 작용한 것으로 사료되었다.

• 한국문헌정보학회지
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• 제58권1호
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• pp.83-97
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• 2024

본 연구에서는 충청북도교육청을 중심으로 한 공동보존관의 설립 타당성을 검토하고자 학교도서관 담당자를 대상으로 설문조사를 실시하였다. 연구결과, 첫째, 조사대상 학교도서관들은 이미 포화도가 극에 달해 개별 도서관은 장서 포화도의 관리와 적정 장서 수의 관리를 요구받는 상황이었다. 둘째, 장서보존을 위한 시설을 갖추고 있는 도서관이 거의 없었다. 셋째, 78%의 학교도서관에서 장서포화도가 이미 75% 이상을 넘고 있고, 이로 인해, 매년 폐기 장서가 폭발적으로 증가하고 있는 것으로 조사되었다. 따라서, 신속한 공동보존 자료관의 체계적인 운영이 필요한 것으로 보인다. 또한 단위 도서관에 보존을 위한 시설을 갖추기 어려운 상황으로 희귀서, 특화자료 등 보존가치가 있는 자료는 공동보존자료관으로 이관이 필요하며, 자료보존 관련 정책 및 규정도 필요할 것이다.

• 한국응급구조학회지
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• 제28권1호
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• pp.35-46
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• 2024

Purpose: This study aimed to compare the oxygen saturation measured at fingertips with unpolished and self-artificial nails (sticker, tip) using a portable pulse oximeter. Methods: The sample comprised 27 women who had used nail care services. Using a pulse oximeter, oxygen saturation was measured at fingertips with unpolished nails in a stable state. Self-fabricated sticker and tip nails were attached to the right and left hands, respectively, using five nail colors (black, blue, green, purple, and brown). Oxygen saturation was measured at fingertips with self-fabricated nails first in the usual manner and then measured again by rotating the oximeter by 90°. Values of oxygen saturation were compared and analyzed using the Friedman test and Wilcoxon signed-rank test with Bonferroni correction using IBM SPSS 26.0. Results: Oxygen saturation values were significantly different among colors for both sticker nails (p=.036) and tip nails (p=.000), with black self-artificial nails tending to demonstrate lower oxygen saturation. Moreover, oxygen saturation values obtained by measuring the usual way on unpolished nails was significantly different than those obtained by rotating the oximeter by 90° on thumb with sticker (p=.001) and tip nails (p=.001). Conclusion: The findings of this study suggest that oxygen saturation should be measured on other fingers except for thumb instead of removing the self-artificial nails in emergency situations. For patients with black self-artificial nails, is the findings recommend measuring oxygen saturation at other body parts such as toes, earlobes, forehead, etc.

• 한국도서관정보학회지
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• 제55권1호
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• pp.27-45
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• 2024

충청북도교육청 소속 공공도서관의 장서 소장 및 보존현황, 장서관리의 어려움, 장서 포화에 대한 예측에 대한 조사를 수행하였다. 충청북도교육청 소속 공공도서관은 극심한 장서 포화로 인한 어려움을 겪고 있어 신속한 공동보존자료관의 체계적인 운영 증대 필요성을 절감하고 있었다. 향후 공동보존자료관으로 이관 시 도서 위주 자료 이관이 주를 이룰 것으로 보인다. 단위 도서관에 보존을 위한 시설을 갖추기 어려운 상황으로 희귀서, 특화자료 등 보존가치가 있는 자료는 공동보존자료관으로 이관이 필요하며, 자료보존 관련 정책 및 규정마련이 필요한 상황이며, 특히 공동보존자료관으로 자료 이관 시 단순한 이용률 저하 자료 등에 대한 이관 기준이 필요할 것으로 보인다. 향후 연구에서는 지자체 소속 공공도서관들의 장서 포화 상태도 조사함으로써 충청북도 전체 공공도서관 자료의 공동보존 방안 모색을 논의할 필요가 있을 것이다.

• KSBB Journal
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• 제15권3호
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• pp.280-284
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• 2000

The simple imcroprocessor device was provided for the control of dissolved oxygen(DO) level. The DO analog signal output from fementer was used as a measurement variable and the agitation speed of fermenter was used as a manipulatio variable. Agitation speed was manipulated to maintain DO level above 10% of saturation condition during cell growth period with microprocessor. Since the experimental resultsshowed that the DO level was maintained above 10% and agitation speed was inverse proportional to DO level ithis simple control device can be used for the DO control of fermenter.

• 산업기술연구
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• 제26권A호
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• pp.89-93
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• 2006

Pulse oximetry, which monitors non-invasively the oxygen saturation in blood, is influenced by patient's respiration, movement or a factor of an environment. Specially, it's difficult to measure a PPG (Photoplethsmography) signal from the moving patient because of the motion artifact. Accordingly, it is required to extract the pure PPG signal from the PPG signal to measure oxygen saturation. In this paper, we propose an adaptive noise canceller to improve the performance of motion artifact removal. Then we design a hardware system for real time monitoring of the oxygen saturation. The proposed algorithm estimates the slope of transition rate between two different wavelength signals.

• Environmental Engineering Research
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• 제21권4호
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• pp.427-435
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• 2016

In this study, change in water-dissolved oxygen (DO) was analyzed under various synthetic water qualities and nanobubbles (NBs) application conditions, such as gas type, initial DO as well as water dissolved, suspended and organic matters contents. When oxygen, rather than air, was introduced into nitrogen-desorbed ultra-pure water, the stagnation time was significantly increased. It took ten days for DO concentration to drop back to saturation. The higher the initial DO concentration, the longer particles were observed above saturation due to particle stability improvement. The oxygen mass transfer rate of 0.0482 mg/L/min was found to reach a maximum at an electrolytic concentration of 0.75 g/L, beyond which the transfer rate decreased due to adsorption of negative ions of the electrolyte at the interface. High levels of turbidity caused by suspended solids have become a barrier to dissolution of NBs oxygen into the water solution, and thus affected the transfer performance. On the other hand, by applying NBs for just an hour, up to 7.2% degradation of glucose as representative organic matter was achieved. Thus, NBs technology would maintain a high DO extent for an extended duration, and thus can improve water quality provided that water chemistry is closely monitored during its application.