• Korean Journal of Chemical Engineering
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• v.36 no.3
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• pp.356-367
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• 2019

This work presents an advanced and systematic approach to analytically design the optimal parameters of a two parameter second-order internal model control (IMC) filter that satisfies operational constraints on the output process, the manipulated variable as well as rate of change of the manipulated variable, for a first-order plus dead time (FOPDT) process. The IMC parameters are designed to minimize a control objective function composed of the weighted sum of the error between the process variable and the set point, and the rate of change of the manipulated variable, and to satisfy the desired constraints. The feasible region of the constrained IMC control parameters was graphically analyzed, as the process parameters and the constraints varied. The resulting constrained IMC control parameters were also used to find the corresponding industrial proportional-integral controller parameters of a Smith predictor structure.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.828-834
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• 1989

On-Line optimization of process units has heretofore been restricted to the individual equipment level using linear approximate models. The advent of the low cost, high speed micro-computer coupled with the speed and robustness of an equation based exact simulator is making real-time optimization of entire process units a reality. The resultant implications for a decision system applied to day-to-day operations, point to a significant change in the way process plants will be managed in the future.

• Korean Journal of Metals and Materials
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• v.48 no.4
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• pp.315-319
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• 2010

In this study, the hydrogen reduction behavior of ball-milled NiO nanopowder was investigated depending on the partial pressure of water vapor. The hydrogen reduction behavior was analyzed by thermogravimetry and hygrometry under heating to 873 K in hydrogen. In order to change the partial pressure of the water vapor, the dew point of hydrogen was controlled in the range of 248 K~293 K by passing high-purity hydrogen through a saturator that contained water. Interestingly, with the increase in the dew point of the hydrogen atmosphere, the first step of the hydrogen reduction process decreased and the second step gradually increased. After the first step, a pore volume analysis revealed that the pore size distribution in the condition with a higher water vapor pressure shifted to a larger size, whereas the opposite appearedat a lower pressure. Thus, it was found that the decrease in the pore volume during the chemical reaction controlled process at a dew point of 248 K caused a reduction in retardation in the diffusion controlled process.

• Journal of KIBIM
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• v.8 no.2
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• pp.10-18
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• 2018

BIM technologies store, share and integrate the information produced in each sector of the construction industry. From this point on, it increases the efficiency of the work. Currently, quantity take-off and process schedule are derived separately based on BIM technology. When calculating the quantity by process, relevant information shall be collected, reinterpreted, and reevaluated as required by the practice. The purpose of this study is to develop an integrated process and quantity management system through BIM collaboration and to build prototypes for steel structures. The main research is to build a construction BIM model for steel structures and a process BIM model through BIM collaboration. Furthermore, necessary information was selected and processed according to the user's needs for integrated management. Relevant integration outcomes are visualized graphically to maximize utilization. Through these studies, a system for integrated control of processes and supplies is provided, and the results are expected to contribute to the improvement of working efficiency and are easily and quickly reflected in design change and process change. In this study, we intended to enhance the usability of information by linking process schedules with quantity calculations based on BIM. Thus, the process for integrated control of the quantity of structural components by process unit and the BIM based schedule information was established. In addition, the efficiency of the information link of the integrated management system was considered for design changes and process schedule changes.

• 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 Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.1-8
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• 2006

In this study a process simulation method was used to analyze the accumulation phenomena of anionic starch in the process white water as the closure level of a fine paper making process is increased. A pilot paper machine was used as a model process. Dynamic simulations of the influence of white water usage ratio and uncoated broke addition ratio on the variation of process variable was monitored as a function of time. Results from the dynamic simulations showed that the volume of reservoirs affected the dynamic behavior of the process. The dynamic behavior of flow rate and dissolved starch concentration in process units were different from each other. The speed of the change of dissolved starch concentration in process units was depend on the starting point of the change of dissolved starch concentration, the length of circulation loop, and the volume of reservoirs.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.1
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• pp.24-34
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• 1985

The study of unsteady gas exchange processes in the inlet and exhaust systems of the single-cylinder 4-stroke cycle spark ignition engine is presented in this paper. The generalized method of characteristics including friction, heat transfer, change of flow area and entropy gradients was used for solving the equations defining the gas exchange process. The path line calculation was also conducted to allow for calculation of the gas composition and entropy change along the path lines, and of the variable specific heat due to the change of temperature and composition. As the result of the simulation, the properties at each point in the inlet and exhaust pipe, pressure and temperature in the cylinder, and charging efficiency were obtained. Pumping loss and residual gas fraction were also computed. The effect of engine speed, exhaust and inlet pipe length on the pumping loss and charging efficiency were studied showing that the results were in agreement with what has been known from experiments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.652-660
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• 2003

T-history method, measuring heat-of-fusion of phase change material (PCM) in sealed tubes, has the advantages of a simple experimental device and no requirements in sampling process. However, a degree of supercooling used in selecting the range of latent heat release and neglecting sensible heat during the phase change process can cause significant errors in determining the heat of fusion in the original method, which has been improved in order to predict better results by us. In the present study, the modified method was applied to a variety of PCM such as paraffin and lauric acid having very small or no supercooling with a satisfactory precision. Also the selection of inflection point and temperature measurement position was fumed out not to affect the accuracy of heat-of-fusion significantly. As a result, the method can provide an appropriate means to assess a new developed PCM by cycle test even if a very accurate value cannot be obtained.

• The Korean Journal of Pain
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• v.24 no.3
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• pp.141-145
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• 2011

Background: Stellate ganglion block is usually performed at the transverse process of C6, because the vertebral artery is located anterior to the transverse process of C7. The purpose of this study is to estimate the location of the transverse process of C6 using the cricoid cartilage in the performance of stellate ganglion block. Methods: We reviewed cervical lateral neutral-flexion-extension views of 48 patients who visited our pain clinic between January and June of 2010. We drew a horizontal line at the surface of the cricoid cartilage in the neutral and extension views of cervical lateral x-rays. We then measured the change in the shortest distance from this horizontal line to the lowest point of the transverse process of C6 between the neutral and extension views. Results: There was a statistically significant difference in the shortest distance from the horizontal line at the surface of the cricoid cartilage to the lowest point of transverse process of C6 between neutral position and neck extension position in both males and females, and between males and females in both neutral position and neck extension position. The cricoid cartilage level was 4.8 mm lower in males and 14.4 mm higher in females than the lowest point of transverse process of C6 in neck extension position. Conclusions: Practitioners should recognize that the cricoid cartilage has cephalad movement in neck extension. In this way, the cricoid cartilage can be still useful as a landmark for stellate ganglion block.

• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.103-113
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• 2018

In this study, Construction work is mainly done outdoors, so earth works, reinforced concrete works, etc. are Non-Working Days to rainfall. In particular, changes in rainfall due to global warming have made air calculation more difficult. Therefore, when establishing the process plan, the change of the rainfall in the area should be identified and Non-Working Days should be calculated. In this study, the time of rainfall change point was identified using the meteorological 'observation' data from 1960 to 2016 in Incheon and RCP 4.5, 'weather forecast' data from 2018 to 2074, Year rainfall and seasonal rainfall. The results showed that rainfall changed point in 1972, 1988, 2013, 2038, 2050 and 2069. In particular, it has been found that non-working days due to rainfall has big changed point as of 2013, 2038 and 2069.