• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.73.3-73
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• 2001

Finishing mill (FM) is set up with rolling conditions (rolling speed, rolling force, roll gap, etc.) calculated by a FSU (Finisher Setup) model considering the temperature, qualities and size of a transfer bar and a strip at the entry and exit of FM before the transfer bar is rolled through FM. If the accuracy of setup is low mass flow unbalance occurs, so that the accuracies of the strip thickness and width become lower or rolling operation fault occurs. Therefore, to enhance the performance of the FSU model and to improve mass flow and the thickness accuracy of a strip in the 7-stand finishing mill using a hot strip speed measurement system. This study is being performed. In this paper, the speed measurement system, a developed neural network for predicting ...

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.19-25
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• 2005

A tunnel that uses the RMR method or the Q-system is called a 'modem tunnel' because the New Austrian Tunneling Method (NATM) is not employed, even though shotcrete and rock bolts are used as support. It is known that the modem tunnel, which is supported by shotcrete, is basically different from the conventional tunnel, which is supported by steel ribs. In order to preserve the load-carrying capacity of the rock mass, loosening and excessive rock deformations must be minimized. Although it is known that this can be achieved by applying shotcrete in the case of the modem tunnel, this has not been clearly demonstrated. In order to inspect the distinctions between the conventional tunnel and the modern tunnel, their support characteristics and the rock loads of the rock mass classifications are compared. Terzaghi's rock load classification was used as the conventional tunnel's representative rock mass classification. The RMR method and the Q-system were adopted as the modem tunnel's representative rock mass classification. The study's results show that the load-carrying capacity of shotcrete, when used as the main support in the modern tunnel, is greater than the load-capacity of the steel ribs used in the conventional tunnel. Because it has been verified that the rock loads of their rock mass classifications are not different, then, according to the rock mass classifications, the load-carrying capacity of the rock mass of the modern tunnel, which uses shotcrete, is not greater than that of the conventional tunnel.

• Journal of Multimedia Information System
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• v.3 no.3
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• pp.97-102
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• 2016

Deep learning enables machines to have perception and can potentially outperform humans in the medical field. It can save a lot of time and reduce human error by detecting certain patterns from medical images without being trained. The main goal of this paper is to build the optimal model for breast mass classification by applying various methods that influence the performance of Convolutional Neural Network (CNN). Google's newly developed software library Tensorflow was used to build CNN and the mammogram dataset used in this study was obtained from 340 breast cancer cases. The best classification performance we achieved was an accuracy of 0.887, sensitivity of 0.903, and specificity of 0.869 for normal tissue versus malignant mass classification with augmented data, more convolutional filters, and ADAM optimizer. A limitation of this method, however, was that it only considered malignant masses which are relatively easier to classify than benign masses. Therefore, further studies are required in order to properly classify any given data for medical uses.

• Membrane and Water Treatment
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• v.3 no.3
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• pp.151-168
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• 2012

Gas sparging is one of the techniques used to control the concentration polarization during ultrafiltration. In this work, the effects of gas sparging in stratified flow regime were investigated during gel layer controlling cross flow ultrafiltration in a rectangular channel. Synthetic solution of pectin was used as the gel forming solute. The liquid and gas flow rates were selected such that a stratified flow regime was prevalent in the channel. A mass transfer model was developed for this system to quantify the effects of gas flow rates on mass transfer coefficient (Sherwood number). The results were compared with the case of no gas sparging. Gas sparging led to an increase of mass transfer coefficient by about 23% in this case. The limitation of the developed model was also evaluated and it was observed that beyond a gas flow rate of 20 l/h, the model was unable to explain the experimental observation, i.e., the decrease in permeate flux with flow rate.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.228-233
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• 2000

An experimental study has been performed regarding heat and mass transfer in a falling film absorber of domestic small-sized absorption chiller/heater. Components were concentrically arranged in cylindrical form : from the center, with a series of low temperature generator, absorber and evaporator. The arrangement of such helical-typed heat exchangers allows to make the system more compact as compared to conventional one. Experimental measurements were conducted with a helical absorber using $LiBr+LiI+LiNO_3+LiCl$ and LiBr solutions. As a result, the heat and mass flux performance of $LiBr+LiI+LiNO_3+LiCl$ solution shows the tendency of $2{\sim}5%$ increase. Therefore, $LiBr+LiI+LiNO_3+LiCl$ solution can be taken consideration into applying to small-sized absorption chiller/heater because of using without crystal through high concentration as 4wt% comparing with LiBr solution.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.931-938
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• 2006

Using high resolution stereoscopic imaging system three digital elevation model of tunnel face is acquired. The images oriented within a given tunnel coordinate system are brought into a stereoscopic vision system enabling three dimensional inspection and evaluation. The possibilities for the prediction ahead and outside of tunnel face have been improved by the digital vision system with 3D model. Interpolated image structures of rock mass between subsequent stereo images will enable to model the rock mass surrounding the opening within a short time at site. The models shall be used as input to numerical simulations on site, comparison of expected and encountered geological conditions, and for the interpretation of geotechnical monitoring results.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.385-391
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• 2004

This paper examines the applicability of DAF-system to the domestic sewers for the effective CSOs treatment. The procedures for the experiment include mainly two steps. One is to analyse the water qualities and settling test of the CSOs and the other focuses on general characteristics of the CSOs such as the removal efficiency of pollutant, the distribution of particle size and mass balance of DAF-system. The result of this study show that the application of DAF-system is more effective and economical than the existing treatment systems because it has two removal mechanisms of sedimentation and flotation simultaneously.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.108-113
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• 2004

This paper presents methods to improve performance of the power supply system in a NASA deep space explorer. In the Stirling engine driven reciprocating Brushless DC (BLDC) generator, the accurate position information of the prime mover is important to diagnose the performance of the engine and prevent distortion of the output power. Since sensors to detect the position are fragile and unreliable, and conventional sensorless techniques have drawbacks in the low speed region, a novel sensorless position detection technique for the prime mover has been proposed and verified. Another major issue of the generator for the spacecraft is power density maximization. The mass of the power system is important to the mass of the satellite. Therefore, the components of the spacecraft should be lightweight. Conventional rectification methods cannot achieve the maximum power possible due to non-optimal current waveforms. The optimal current waveform for maximizing power density and minimizing machine size and weight in a nonsinusoidal power supply system has been derived, incorporated in a control system, and verified by simulation work.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.66-73
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• 2004

This paper presents wafer motion modeling of transfer unit in clean tube system, which was developed as a means for transferring the air-floated wafers inside the closed tube filled with the super clean airs. When the wafer is transferred in x direction with an initial velocity the motion along x direction can be modeled as a simple decaying motion due to viscous friction of the fluid. But, the motion in y direction is modeled as a mass-spring-damper system where the recovering force by air jets issued from the perforated is modeled as a linear spring. Experiments with a clean tube system built fur 12 wafer show the validity of the presented force and motion models.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.235-242
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• 2011

The control performance in active structural control system can be drastically deteriorated when the modeling errors and the uncertainties existing in the disturbances are disregarded in the designing stage. It can even throw the control system into an unstable phase, resulting in out of control against the seismic excitations. The purpose of the study is to investigate the control effectiveness of a non-linear control system called sliding mode controller(SMC) in cooperation with a Tuned Mass Damper subjected to the three seismic excitations selected from the FFT analysis. Even though the transient performance such as settling time and overshoot were deteriorated, the robustness against the system stability was appeared from SMC when the structural masses and stiffness perturbed within the range of ${\pm}30%$. SMC is a feasible technique for active structural control in cooperation with TMD against seismic disturbances, exhibiting robustness in perturbation of system stiffness and mass as well as uncertainties of the disturbances.