• 대한환경공학회지
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• 제27권4호
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• pp.409-413
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• 2005

본 논문에는 자가영양균의 최대비성장율 추정법이 제시되었다. 먼저 질산화균의 농도가 질산화 된 암모니아, 슬러지 일령 및 사멸계수를 이용하여 시뮬레이션 되었고, 다음단계로 과잉암모니아를 공급하여 질산화균의 호흡율을 측정하였다. 자가영양균의 최대비성장율은 ${\mu}_{max,A}\;=\;OUR_{max,A}/Y_A$의 관계를 통해 계산되어질 수 있으며 추정된 최대비성장율은 운전기간에 걸쳐 일정한 값을 가지지 앉고 시간에 따라 변화한다는 결과를 얻었다. 본 연구를 통해 최대호흡율을 이용한 최대비성장율의 동적 추정법이 수행되었고, 일정한 최대비성장율를 이용한 처리장 운전결과 예측은 처리장 거동을 예측할 수 없으며 활성슬러지공정의 성능예측을 위한 시뮬레이션을 위해서는 동적 추정된 매개변수의 사용이 필요함을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.1013-1018
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• 2014

In this study, we developed kinetic models to predict the growth of pathogenic Escherichia coli on cheeses during storage at constant and changing temperatures. A five-strain mixture of pathogenic E. coli was inoculated onto natural cheeses (Brie and Camembert) and processed cheeses (sliced Mozzarella and sliced Cheddar) at 3 to 4 log CFU/g. The inoculated cheeses were stored at 4, 10, 15, 25, and $30^{\circ}C$ for 1 to 320 h, with a different storage time being used for each temperature. Total bacteria and E. coli cells were enumerated on tryptic soy agar and MacConkey sorbitol agar, respectively. E. coli growth data were fitted to the Baranyi model to calculate the maximum specific growth rate (${\mu}_{max}$; log CFU/g/h), lag phase duration (LPD; h), lower asymptote (log CFU/g), and upper asymptote (log CFU/g). The kinetic parameters were then analyzed as a function of storage temperature, using the square root model, polynomial equation, and linear equation. A dynamic model was also developed for varying temperature. The model performance was evaluated against observed data, and the root mean square error (RMSE) was calculated. At $4^{\circ}C$, E. coli cell growth was not observed on any cheese. However, E. coli growth was observed at $10{\circ}C$ to $30^{\circ}C$C with a ${\mu}_{max}$ of 0.01 to 1.03 log CFU/g/h, depending on the cheese. The ${\mu}_{max}$ values increased as temperature increased, while LPD values decreased, and ${\mu}_{max}$ and LPD values were different among the four types of cheese. The developed models showed adequate performance (RMSE = 0.176-0.337), indicating that these models should be useful for describing the growth kinetics of E. coli on various cheeses.

• 한국항행학회논문지
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• 제15권4호
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• pp.487-494
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• 2011

레이더를 이용한 항적 융합 알고리즘은 반드시 필요하며, 이를 통해서 높은 신뢰성을 확보할 수 있다. 본 논문에서는 칼만필터 보다 성능이 좋다고 알려진 IMM(Interacting Multiple Model) 필터를 이용하여 다중 레이더 융합 알고리즘을 제안하였다. 분산형 융합 방식을 적용하였고, 부필터 3개, 주필터 1개를 이용하였다. 성능분석은 등속운동, 가속운동, 선회 등 항공기 기동을 묘사한 가상의 레이더 데이터를 이용하여 분석하였다. 성능분석 결과, 항공기가 기동하는 구간에서도 좋은 추적 성능을 보였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.557-562
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• 2004

A surface-piercing barrier model is presented for understanding morphological development in the sheltered region and investigating the main factors causing the severe accumulation. Surface-piercing structures like vertical barriers, surface docks and floating breakwaters are recently favored from the point of view of a marine scenario since they do not in general partition the natural sea. The numerical solutions are compared with experimental data on wave profiles and morphological change rates within a rectangular harbor of a constant depth protected by surface-piercing thin breakwaters as a simplified problem. Our numerical study involves several modules: 1) wave dynamics analyzed by a plane-wave approximation, 2) suspended sediment transport combined with sediment erosion-deposition model, and 3) concurrent morphological changes. Scattering waves are solved by using a plane wave method without inclusion of evanescent modes. Evanescent modes are only considered in predicting the reflection ratio against the vertical barrier and energy losses due to vortex shedding from the lower edge of plate are taken into account. A new relationship to relate the near-bed concentration to the depth-mean concentration is presented by analyzing the vertical structure of concentration. The numerical solutions were also compared with experimental data on morphological changes within a rectangular harbor of constant water depth. Through the numerical experiments, the vortex-induced flow appears to be not ignorable in predicting the morphological changes although the immersion depth of a plate is not deep.

• Advances in environmental research
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• 제4권1호
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• pp.25-38
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• 2015

Wastewaters of textile industry cause high volume colour and harmful substance pollutions. Photocatalytic degradation is a method which gives opportunity of reduction of organic pollutants such as dye containing wastewaters. In this study, photocatalytic degradation of C.I. Basic Yellow 28 (BY28) as a model dye contaminant was carried out using Degussa P25 in a photocatalytic reactor. The experiments were followed out at three different azo dye concentrations in a reactor equipped UV-A lamp (365 nm) as a light source. Azo dye removal efficiencies were examined with total organic carbon and UV-vis measurements. As a result of experiments, maximum degradation efficiency was obtained as 100% at BY28 concentration of $50mgL^{-1}$ for the reaction time of 2.5 h. The photodegradation of BY28 was described by a pseudo-first-order kinetic model modified with the langmuir-Hinshelwood mechanism. The adsorption equilibrium constant and the rate constant of the surface reaction were calculated as $K_{dye}=6.689{\cdot}10^{-2}L\;mg^{-1}$ and $k_c=0.599mg\;L^{-1}min^{-1}$, respectively.

• 드라이브 ㆍ 컨트롤
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• 제12권3호
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• pp.11-17
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• 2015

An intelligent deburring control (IDC) device is used to control the constant force for a deburring tool mounted on the end-effector of a robotic arm. This device maintains a constant contact force between the deburring tool and the workpiece in order to provide a good deburring performance. In this paper, we build a mathematical model in Matlab/Simulink to estimate the force control mechanism of the pneumatic system for the IDC device. The Simulink blocks are built for each separate part and are linked into an integrated simulation system. Such a model also relies on the effects of the flow rate through the valve, air compressibility in the cylinder, and time delay in the pressure valve. The results of the simulation are compared to a simple experiment in which convenient math modeling is performed. These results are then used to optimize the mechanical design and to develop a force control algorithm for the pneumatic cylinder.

• Composites Research
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• 제22권4호
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• pp.27-32
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• 2009

본 연구에서는 충돌속도가 다르지만, 총 충돌에너지는 동일하게 유지한 상태에서 충돌을 가했을 때 발포 고분자의 응력-변형률 관계와 충돌에너지 흡수 특성에 관하여 고찰하였다. 이는 충돌시 관성과 변형률 속도에 변화를 주어 재료의 반응거동 및 특성을 파악하기 위함이다. 두가지 다른 밀도(64 $kg/m^3$, 89 $kg/m^3$)를 갖는 발포고분자시편에 대한 준정적시험과 충돌시험이 수행되었다. 또한 Sherwood-Frost 모델과 임펄스 모멘텀 이론의 두가지가 연성된 방정식을이용하여 발포고분자의 구성방정식으로 제안하였다.\ 제안된 구성방정식을 이용하여, 응력변형률 선도를 구하고, 충돌시험결과와 비교하여, 본 구성방정식이 우수하게 결과를 예측할 수 있는 것으로 나타났다.

• 대한설비공학회지:설비저널
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• 제17권6호
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• pp.696-707
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• 1988

This study simulates a typical solar system using the transient simulation program TRNSYS, and calculates the maximum cooling load of the model room of $50m^2$. In this study, energy rate control method is used in calculating a maximum cooling load. On the ground of the maximum cooling load of the model room, the variables that have an effect on the solar collection performance of the solar system are made a selection. Also in this study the trend of the solar collection performance is shown as the variables change. The results show that the variables which have an effect on the collection performance are collector area, collector mass flow rate, collector slope and the volume of storage tank, and the optimal value of Ac/Vt is not constant but varies as the collector area and the collector mass flow rate. Also the results show that for cooling system the optimal value of the collector slope is latitude minus $15^{\circ}$ during the seasonal operations, and twenty percent of the maximum cooling load is saved with the aid of the solar energy.

• 천문학회보
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• 제42권1호
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• pp.39.2-39.2
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• 2017

Stars form through the gravitational collapse of molecular clouds. However, the rate at which a star gains most of its mass and the physics that drives the main phase of stellar growth is still unclear. The typical luminosity of observed protostars is smaller than what expected from the Shu's inside-out collapse model, which predicts a constant mass accretion rate. The episodic accretion model has been suggested as a solution of this luminosity problem. The JCMT Transient survey is a long term monitoring program using JCMT/SCUBA-2 to detect accretion variability of protostars in the eight nearby star-forming regions. Recently, we found a rise of the 850 micron flux at a clump in the Serpens main region at the rate of ~17% relative to the mean flux over previous observations. The submm clump is associated with a class I protostar, EC53, which has been reported as a binary system with a periodic variability. In this talk, we will provide a brief overview of the JCMT Transient Survey project, present the detection of the variable source, and discuss about follow-up observations.

• 대한산업공학회지
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• 제33권2호
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• pp.246-253
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• 2007

All of the machines in a production line can be classified into bottleneck and non-bottleneck machines. A bottleneck is a resource whose capacity limits the throughput of the whole production facility. This paper addresses a batch sizing problem at the bottleneck machine. Traditionally, most batch sizing decisions have been made based on the EOQ (economic order quantity) model where setup and inventory costs are considered while throughput rate is assumed to be given. However, since batch size affects the capacity of the bottleneck machine, the throughput rate may not be constant. As the batch size increases, the frequency of the setup decreases. The saved setup time can be transferred to processing time, which results in higher throughput. But, the larger batch size may also result in longer lead time and larger WIP inventory level. This paper presents an alternative method to determine batch size at the bottleneck machine in a manufacturing line. A linear search algorithm is introduced to find optimal throughput rate and batch size at the same time. Numerical examples are provided to see how the proposed method works and to investigate the effects of some parameters.