• 대한환경공학회지
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• 제31권2호
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• pp.102-108
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• 2009

연속회분식반응기에서 측정되는 기초상용계측기의 프로파일은 공정 내에서 수행되는 유기오염물질 및 영양염류 제거반응의 진행 정도에 대한 정보를 제공할 수 있다. 특히 호기성 반응구간에 측정되는 pH나 DO, ORP의 변곡점 등의 정보를 이용한 반응 종료 감지는 널리 알려진 응용사례라고 할 수 있다. 그러나 이러한 정보들은 반응의 종료 여부에 대한 정보를 제공할 뿐, 현재 공정에 가해지는 부하에 대한 정보를 제공하지는 못한다. 본 논문에서는 운전자에게 공정 유입수 내의 호기적 반응을 요하는 부하, 즉 암모니아 부하 및 유기물 부하의 고/중/저에 관한 정보를 제공할 수 있는 기초상용계측기의 정보를 활용한 진단 알고리즘을 개발하였다. 본 알고리즘으로 인해, 연속회분식반응기를 운전할 시에 수시로 변화하는 유입수의 부하를 습식분석 없이 자동 계측기 프로파일로부터 얻어낼 수 있을 것으로 사료된다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
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• pp.19-22
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• 2001

In this paper, Streaming Current Monitor (SCM), Pilot Filter (PF) and Coagulant Feeding System(CFS) for fuzzy neural network are used as a coagulation control method in WTP and the results are compared. Several parameters such as coagulant dosage, pH, and turbidity have been changed to find the response characteristic of each equipment. SCM, PF and CFS responded for certain parameters but the range of sensitivity was different each other. It is demonstrated that WTP will be operated more efficiently when SCM, PF and CFS are used as coagulation control strategy.

• Asian-Australasian Journal of Animal Sciences
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• 제14권5호
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• pp.655-667
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• 2001

This experiment was conducted to investigate the effect of feeding a low CP diet supplemented with synthetic amino acids on performance, nutrient utilization and carcass characteristics of finishing pigs fed under a three-phase feeding regimen. Ninety-six finishing pigs (Landrace$\times$Large White$\times$Duroc), $55.75kg{\pm}0.65$ of initial body weight, were blocked by weight and sex and allotted to four dietary treatments in a randomized block design. There were six pens per treatment and four pigs per pen. Pigs were fed a 16%-14%-12% CP (for phase I-II-III, respectively), sequence of diets. Dietary treatments were 1) Control, 2) Con+L (a sequence of diets reduced in CP by l percentage unit with lysine (L) supplementation, 3) Con+LMT (a sequence of diets reduced in CP by 2 percentage unit with LYS, methionine (MET) and threonine (THE) supplementation) and 4) Con+LMTT (a sequence of diets reduced in CP by 3 percentage unit with LYS, MET, THR and tryptophan (TRP) supplementation). The finishing period (55 to 105 kg) was divided into three phases (55 to 72 kg, 72 to 90 kg and 90 to 105 kg). Pigs fed either the control or Con+L diet grew faster (p<0.05) than pigs fed the Con-LMT or Con+LMTT diet. There was no difference in ADFI among dietary treatments. Phosphorus (P) digestibility was lowest in the control group and highest in the Con+LMTT group (p<0.05). Within each phase, no significant differences in dry matter (DM) and CP digestibilities were found. Although some amino acid digestibilities were affected by dietary treatments, digestibilities of essential amino acids (EAA), non-essential amino acids (NEAA) and total amino acid were not significantly influenced by dietary treatments. For the entire experiment periods, Con+L, Con+LMT and Con+LMTT treatments resulted in 13.4, 18.8 and 21.6% lower total N excretion compared with the control. Con+LMT and Con+LMTT treatments showed significantly lower BUN concentration compared with the control and Con+L treatment (p<0.05), but there was no significant difference in BUN concentration between pigs fed the control and Con+L treatment or between pigs fed Con+LMT and Con+LMTT treatments (p>0.05). Carcass length, backfat thickness and carcass grade were not significantly affected by dietary treatments (p>0.05). In conclusion, reducing dietary CP level by 1 percentage unit and supplementing only LYS at each phase could be a very beneficial feeding strategy for finishing pigs fed under a three phase feeding regimen in terms of both environmental and economical aspects.

• The Korean Journal of Pain
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• 제31권1호
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• pp.10-15
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• 2018

Background: To identify a new strategy for postoperative pain management, we investigated the analgesic effects of allopregnanolone (Allo) in an incisional pain model, and also assessed its effects on the activities of the primary afferent fibers at the dorsal horn. Methods: In experiment 1, 45 rats were assigned to Control, Allo small-dose (0.16 mg/kg), and Allo large-dose (1.6 mg/kg) groups (n = 15 in each). The weight bearing and mechanical withdrawal thresholds of the hind limb were measured before and at 2, 24, 48, and 168 h after Brennan's surgery. In experiment 2, 16 rats were assigned to Control and Allo (0.16 mg/kg) groups (n = 8 in each). The degree of spontaneous pain was measured using the grimace scale after the surgery. Activities of the primary afferent fibers in the spinal cord (L6) were evaluated using immunohistochemical staining. Results: In experiment 1, the withdrawal threshold of the Allo small-dose group was significantly higher than that of the Control group at 2 h after surgery. Intergroup differences in weight bearing were not significant. In experiment 2, intergroup differences in the grimace scale scores were not significant. Substance P release in the Allo (0.16 mg/kg) group was significantly lower than that in the Control group. Conclusions: Systemic administration of Allo inhibited mechanical allodynia and activities of the primary afferent fibers at the dorsal horn in a rat postoperative pain model. Allo was proposed as a candidate for postoperative pain management.

• 한국지능시스템학회논문지
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• 제24권3호
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• pp.330-336
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• 2014

연속교반탱크반응기, 담수화 플랜트, 증류탑, pH 중화 프로세스 등을 포함한 많은 산업용 프로세스들은 높은 비선형성과 시변 특성으로 인해 제어가 까다로워 보다 정밀하고 안정된 성능을 가지는 제어기를 설계하려는 많은 노력들이 있어 왔다. 본 논문에서는 기존 연구의 단점을 개선한 CSTR 프로세스의 농도제어용 PID 제어기를 동조하는 문제를 다룬다. 액추에이터 포화 문제를 극복하기 위해 PID 제어기에는 적분기 안티와인드업 피드백 루프가 구성되며, PID 제어기의 파라미터는 전체 제어 프로세스가 만족스러운 설정치 추종 성능을 가지도록 진화연산(EA)에 의해 동조된다. 제안하는 방법은 시뮬레이션을 통해 설정치 추종 성능, 외란 억제 성능과 파라미터 변동에 대한 강인성을 확인한다.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.644-651
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on water quality such as turbidity, temperature, pH and alkalinity. However, the process of chemical reaction to improve water quality (e.g., turbidity) by chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts using Jar-test data. In this paper, a systematic control strategy is proposed to derive the optimum dosage of coagulant, PAC(Polymerized Aluminium Chloride), using Jar-test results. A neural network model is developed for coagulant dosing and purifying process by means of six input variables (turbidity, temperature, pH, alkalinity of raw water, PAC feed rate, turbidity in flocculation) and one output variable, while considering the relationships to the reaction of coagulation and flocculation. The model is utilized to derive the optimum coagulant dosage (in the sense of minimizing turbidity of water in flocculator). The ability of the proposed control scheme validated through the field test has proved to be of considerable practical value.

• Asian-Australasian Journal of Animal Sciences
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• 제26권3호
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• pp.394-400
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• 2013

A total of 192 broiler chicks were used to evaluate the influence of dietary ${\alpha}$-lipoic acid (ALA) on growth performance, carcass characteristics and meat quality of broiler chickens with the purpose of developing a strategy to prevent the occurrence of pale, soft, and exudative (PSE) meat and to improve the meat quality of broilers. At 22 d of age, birds were allocated to 4 ALA treatments (0, 400, 800, and 1200 ppm). The results showed that dietary ALA significantly decreased average feed intake (AFI), average daily gain (ADG), final live body weight (BW) and carcass weight (p<0.05), while no difference in feed conversion ratio (FCR) was detected among chickens fed with and without ALA. Abdominal fat weight significantly decreased (p<0.05) for broilers fed 800 and 1200 ppm ALA. However when calculated as the percentage of carcass weight there was no significant difference between control and ALA treatments. Meat quality measurements showed that dietary ALA regulated postmortem glycolysis and improved meat quality as evidenced by increased muscle pH and decreased drip loss of meat (p<0.05). Although ALA did not change the tenderness of meat as indicated by meat shear force, dietary ALA decreased collagen content and mRNA expression of COL3A1 gene (p<0.05). In conclusion, the results indicate that dietary ALA may contribute to the improvement of meat quality in broilers.

• Animal Bioscience
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• 제35권2호
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• pp.184-195
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• 2022

Objective: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle. Methods: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d. Results: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation. Conclusion: The results demonstrated dietary ADY improved ruminal fermentation dose-dependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation.

• 동력기계공학회지
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• 제9권4호
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• pp.162-167
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that are cost less and faster than previous semiconductor processes have been developed for the production of electric paper and RFID(Radio Frequency IDentification). The system proposed in this study prints by spraying the molten metal. And this system consist of a nozzle, heating furnace, operating actuator and an XYZ 3-axis stage. As an operating system, the piezoelectric(PZT) actuator is a very useful tool for position control of the metal printing system. However, the PZT actuator has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element. This hysteresis causes problem position control characteristics in the system and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. In order to reduce the hysteresis nonlinearity of the PZT actuator, this proposed a inverse hysteresis model and a mathematic modeling method that can express the geometric relationship between voltage and displacement. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good tracking performance.

• 대한환경공학회지
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• 제35권4호
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• pp.294-300
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• 2013

혐기성 암모늄 산화공정 전처리로써 적절한 $NO_2{^-}-N/NH_4{^+}-N$ 반응비율에 맞는 유출수를 생성하기 위한 연구실 규모의 연속 회분식 반응기 시스템을 적용하였다. 부분아질산화 적용에 있어서 운전인자들을 이용하여 AOB를 활성화하고, 동시에 NOB를 억제하는 다양한 전략이 있다. 하지만 적용된 인자들은 명확히 정의되지 않고 아질산 축적에 있어서 극복할 점이 있다. 본 연구의 목적은 부분아질산화의 주 인자를 조사하여 안정적인 공정을 구축하는데 있다. 부분아질산화 시스템을 구축하기 위하여 우세적인 인자인 온도, 중탄산알칼리도, pH를 평가하고자 한다. 실험의 결과로써 알맞은 알칼리도 비가 $35^{\circ}C$와 상온 두가지 온도범위에 안정적인 50% 부분아질산화가 이루어졌다. 이는 질산화시 필요한 알칼리도를 50% 아질산화에 맞추어 주입하여 질산화과정을 억제하는 것이다. 알칼리도 비는 pH 조절없이 50% 부분아질산화의 전략으로 제안한다. 유출수의 $NO_2{^-}-N/NH_4{^+}-N$ 비가 거의 100%에 다다랐을 때 중탄산알칼리도는 각각 6.8, 6.7이 되었다. PCR-DGGE의 미생물 분석 결과 암모늄산화균이 지배적인 질산화균임을 알 수 있었으며 NOB는 억제되어 활성을 잃은 것으로 사료된다.