• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.25-29
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• 2002

Single ion exchange process was used, and the ion exchange behavior and mechanical properties were investigated in substrate glass for flat panel display. In order to study the effects of ion exchange, ion exchange behavior with ion penetration depth, amount of ion exchange, density and thermal expansion was measured according to the time and temperature. The mechanical properties were evaluated by the three point bending test and curvature change, and then the fracture patterns were investigated by optical microscope.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.153-160
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• 2001

In order to analyze the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to high temperature. Then, the degradation process was evaluated by comparing contact angle, surface potential, surface resistivity, and XPS. The experimental results showed that the amount of weight loss, contact angle, surface potential and surface resistivity increased up to 200 $^{\circ}C$ as a function of temperature. These phenomena show the existence of hydrophobic surface. With the change to the hydrophobic surface and the electrical potential and resistivity on FRP surface increased. In XPS to analyze surface chemical structures, the increased hydrophobicity in thermal increase of unsaturated double bond in carbon chains. Aslo, thermal treatment caused the discoloration on the point of treated surface. These phenomena were attributed to the generations of ether group.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.767-770
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• 2001

Edge detection is one of issues with essential importance in the area of image process. An edge in image is a boundary or contour which a significant change occurs in image intensity. In the paper, we process edge detection algorithms which are based on Potts automata. The dynamical behavior of these automata is completely determined by Lyapunov operators for sequential and parallel update. If Potts Automata convergence to fixed points, then it can be used to image processing. From the generalized Potts automata point of view, we propose a Potts Automata technique for detecting edge. Based on the experimental results we discuss the advantage and efficiency.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.2
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• pp.17-33
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• 1993

This paper is the on-site case study of the shaping of townscape of port towns in Korea. Inchon has been experienced the rapid urbanization after the opening of a port. Inchon is selected because of the relatively rapid process, the apparent event and influence, and the enough referneces of data about the landscape formation and transformation. As the value of historical landscape, it is very significant to study Inchon and the causes of change in townscape depend on the external element-the opening of a port, Japan colonial policy, economic progress, nationwide development. The main purpose of this study is scrutinized the process, the cause and effect, and the contents and the form of shaping of townscape. The result of the interpretation of landscape is never perfect but only a starting point. Finally this study will be applied to the pragmatic task as a basic tool which construct the desirable image of the city.

• Communications for Statistical Applications and Methods
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• v.27 no.2
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• pp.163-175
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• 2020

We consider a wide class of general weakly-dependent processes, called ψ-weak dependence, which unify almost all weak dependence structures of interest found in statistics under natural conditions on process parameters, such as mixing, association, Bernoulli shifts, and Markovian sequences. For detecting the tail behavior of the weakly dependent processes, change point tests are developed by means of cumulative sum (CUSUM) statistics with the empirical distribution functions of sample extremes. The null limiting distribution is established as a Brownian bridge. Its proof is based on the ψ-weak dependence structure and the existence of the phantom distribution function of stationary weakly-dependent processes. A Monte-Carlo study is conducted to see the performance of sizes and powers of the CUSUM tests in GARCH(1, 1) models; in addition, real data applications are given with log-returns of financial data such as the Korean stock price index.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.636-642
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• 2000

A method for reducing the contact noise of the Progressive Multi-Leaf Spring was investigated. It was found that the contact noise between the main and the help springs is the main source of the noise through our experiments. The conclusions from our experiments were compared with those from our numerical analysis by use of ABAQUS. The main parameters for the unexpected noise in the leaf spring were investigated through structural analysis to make describing noise generation. The contact process between the two leaves is examined by numerical calculations by ABAQUS. The noise produced by the leaf spring could be dramatically reduced by changing the shape of help spring so as to remove a translational jump of the contact point between the main and the help springs. Even with the help spring of the new proposed shape the stiffness of the whole spring did not change much.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.563-569
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• 2015

A chemical reaction occurring in CSTR (Continuous Stirred Tank Reactor) is significantly affected by the concentration, temperature, pressure, and reacting time of materials, and thus it has strong nonlinear and time-varying characteristics. Also, when an existing linear PID controller with fixed gain is used, the performance could deteriorate or could be unstable if the system parameters change due to the change in the operating point of CSTR. In this study, a technique for the design of a fuzzy PD plus I controller was proposed for the temperature control of a CSTR process. In the fuzzy PD plus I controller, a linear integral controller was added to a fuzzy PD controller in parallel, and the steady-state performance could be improved based on this. For the fuzzy membership function, a Gaussian type was used; for the fuzzy inference, the Max-Min method of Mamdani was used; and for the defuzzification, the center of gravity method was used. In addition, the saturation state of the actuator was also considered during controller design. The validity of the proposed method was examined by comparing the set-point tracking performance and the robustness to the parameter change with those of an adaptive controller and a nonlinear proportional-integral-differential controller.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.861-863
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• 2014

Fingerprinting technique exists at the position assumption system for the service of indoor location-based. However, there is a problem it takes a long time to build fingerprinting map. We need to verify that received signal of WAP(wireless access point) is similar at all times in a similar space in order to solve these problems. This paper proposes a plan that is able to build fingerprinting map by using the received signal data of WAP. To do this, change the positon of WAP in the same space, It is confirmed the process of change of the RSSI corresponding to the distance. We also confirmed that the RSSI collected from elsewhere in the space a similar change in the same manner.

• The Journal of Korean Institute of Information Technology
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• v.17 no.6
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• pp.9-16
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• 2019

Companies that want to improve their manufacturing processes have recently introduced the smart factory, which is particularly noticeable. The ultimate goal is to maximize the area of the smart factory that performs the process of the production facility completely with minimal manual control and to minimize errors of reasoning. This research is a part of a project for unmanned production, management, packaging, and delivery management and the detection of the start point of rebars to perform the automatic calibration of the rollers through the tracking of the automated facilities of unmanned production. It must meet the requirement to accurately track the position from the start point to the end point. In order to improve the tracking performance, it is important to set the accurate start point. However, the probability of tracking errors is high depending on environments such as illumination and dust through the conventional time-based detection method. In this paper, we propose a starting point detection method using the average brightness change of high speed IR camera to reduce the errors according to the environments, As a result, its performance is improved by more than 15%.

• Korean Journal of Materials Research
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• v.26 no.12
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• pp.681-687
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• 2016

Zirconium(Zr) nuclear fuel cladding tubes are made using a three-time pilgering and annealing process. In order to remove the oxidized layer and impurities on the surface of the tube, a pickling process is required. Zr is dissolved in HF and $HNO_3$ mixed acid during the process and pickling waste acid, including dissolved Zr, is totally discarded after being neutralized. In this study, the waste acid was recycled by adding $BaF_2$, which reacted with the Zr ion involved in the waste acid; $Ba_2ZrF_8$ was subsequently precipitated due to its low solubility in water. It is very difficult to extract zirconium from the as-recovered $Ba_2ZrF_8$ because its melting temperature is $1031^{\circ}C$. Hence, we tried to recover Zr using an electrowinning process with a low temperature molten salt compound that was fabricated by adding $ZrF_4$ to $Ba_2ZrF_8$ to decrease the melting point. Change of the Zr redox potential was observed using cyclic voltammetry; the voltage change of the cell was observed by polarization and chronopotentiometry. The structure of the electrodeposited Zr was analyzed and the electrodeposition characteristics were also evaluated.