• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.395-400
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• 2015

Obtaining the parameters for PID controllers based on limit cycle information for the process in a relay controlled feedback loop has become an accepted practical procedure. If the form of the plant transfer function is known, exact expressions for the limit cycle frequency and amplitude can be derived so that their measurements, assumed error free, can be used to calculate the true parameter value. In the literature, parameter estimation for an assumed form of the plant transfer function has generally been considered for disturbance free cases, except a recently published work of the author. In this paper additional simulation results are reported on exact parameter estimation from relay autotuning under static load disturbances.

• ETRI Journal
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• 제24권4호
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• pp.280-289
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• 2002

In this work, we present a novel approach to the bit allocation problem that aims to minimize overall distortion subject to a bit rate constraint. The optimal solution can be found by the Lagrangian method with dynamic programming. However, the optimal bit allocation for block-based interframe coding is practically unattainable because of the interframe dependency of macroblocks caused by motion compensation. To reduce the computational burden while maintaining a result close to the optimum, i.e., near optimum, we propose an alternative method. First, we present a partitioned form of the bit allocation problem: a "frame-level problem" and "one-frame macroblock-level problems." We show that the solution to this new form is also the solution to the conventional bit allocation problem. Further, we propose a bit allocation algorithm using a "two-phase optimization technique" with an interframe dependency model and a rate-distortion model.

• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.218-225
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• 2020

The purpose of this paper is to establish an IoT-based big data platform that can check the space and form analysis in various play cultures of children. Therefore, to this end, in order to understand the healthy play culture of children, we are going to build a big data platform that allows IoT and smart devices to work together to collect data. Therefore, the goal of this study is to develop a big data platform linked to IoT first in order to collect data related to observation of children's mobile movements. Using the developed big data platform, children's play culture can be checked anywhere through observation and intuitive UI design, quick information can be automatically collected and real-time feedback, data collected through repeaters can be aggregated and analyzed, and systematic database can be utilized in the form of big data.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.206-207
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• 2015

Due to the nature of construction industry which is labor-intensive and outdoor mobile production industry, climatic changes work as a major factor affecting construction period and safety accident. In Korea, changes in the amount of precipitation are more severe than those in climate. In addition, climatic changes are also shown as a change in precipitation form. Thus, this study aims to provide baseline data for establishing safety regulations at construction sites by analyzing fatal accidents by precipitation type.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.799-808
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• 2017

Failure of a redundant long-span bridge is often described by innumerable failure modes, which make the structural system reliability analysis become a computationally intractable work. In this paper, an innovative procedure is proposed to efficiently identify the dominant failure modes and quantify the structural reliability for a long-span bridge system. The procedure is programmed by ANSYS and MATLAB. Considering the correlation between failure paths, a new branch and bound operation criteria is applied to the traditional stage critical strength branch and bound algorithm. Computational effort can be saved by ignoring the redundant failure paths as early as possible. The reliability of dominant failure mode is computed by FORM, since the limit state function of failure mode can be expressed by the final stage critical strength. PNET method and FORM for system are suggested to be the suitable calculation method for the bridge system reliability. By applying the procedure to a CFST arch bridge, the proposed method is demonstrated suitable to the system reliability analysis for long-span bridge structure.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.1978-1980
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• 2009

A mesostructured form of carbon was fabricated from a template of mesostructured silica by using pentane, an aliphatic hydrocarbon precursor. To synthesize the mesostructured silica, a buffered (pH of 6.5) mixture of nonionic Pluronic P123 surfactant, sodium silicate, and acetic acid were used. The impregnated silica with Fe$(CO)_5$ (wt 5%) and pentane was placed in a quartz tube, treated with pentane vapor at 800 ${^{\circ}C}$ for two hours to synthesize the mesostructured carbon. The XRD patterns of the carbon replica in the low/wide angle regions, its TEM images, and nitrogen adsorption-desorption isotherm revealed that the long-range framework order of mesostructure with the pore size centered on 2.8 nm was maintained to some extent mainly due to some portions of mesophase carbon that work as a support to fix the hexagonal frameworks by anchoring on the pore surface with an improved graphitic character. The dc conductivity of the mesostructured carbon in pressed powder form at 6.0 MPa was 2.08 S/cm.

• Journal of the Korean Home Economics Association
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• 제38권5호
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• pp.79-90
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• 2000

The purpose of this research is to offer basic data for the study of men's suit by investigating the preference of design and form for men's suits. For data collection, a questionnaire was composed stymie of suits, form of lapel and vent of suits etc‥‥ The subjects of this research were male aged 20-59 and resided in Seoul and the capital region. The results of the research are summarized as the following: 1. Most men tend to prefer a set of suits rather than combination and formal style rather than casual or character style. And most of men like a little enough fittiness of suits. 2. Most men tend to prefer single-breasted jacket rather than double-breasted one. they also tend to prefer notched lapel and no vent jacket, especially men who work in sale, office and an independent enterprise. 3. Men who aged 20-40 tend to prefer classical pants, and one who aged 50 like wide pants. They also tend to prefer pants with pleats rather than one with darts. 4. Most men tend to prefer plain cloth rather than check, stripe pattem, and they tend to select blue and black color as their suits.

• Language and Information
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• 제18권1호
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• pp.53-75
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• 2014

This study discovers the dynamic nature of an interactional hierarchy as well as an institutional hierarchy in the use of Korean honorifics. Data was collected from the conversations of two Korean female interlocutors. The interlocutors met for the first time in the U.S. and often changed their use of honorifics. The paper examines the method in which the two interlocutors negotiate hierarchies during interaction and how the negotiation is reflected in their use of honorific shifts. The paper also investigates honorific shifts in terms of self-representation to suggest that there is another hierarchy at work other than the institutional hierarchy. An examination of the data shows that the shifts occurred not randomly but strategically. The findings suggest that 1) interlocutors may negotiate interactional hierarchy during their conversation, often in the same sentence, 2) interactional hierarchy often cross the boundary of the institutional hierarchy to obtain interactional goals, in this case, intimacy, and 3) the utterance contents may play a significant role in the interlocutors' honorific shifts.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제30권2호
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• pp.62-73
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• 1998

The aim of this work was to investigate the effects of pigment composition on the calendering response and structure of the coated paper. Calendering response of the coated paper was determined from the gloss values of the uncalendered and calendered coated papers, and the relationship between gloss and coating structure was discussed. The surface and cross section of the coating layer was observed using a scanning electron microscope to examine the coating structure. Coating layers were hardened in epoxy resin and polished with carbimet paper disc for preparing SEM samples. Maximum calendering response was obtained for the coated paper prepared from 80pph of clay and 20pph of ground calcium carbonate (GCC) as pigments. Photomicrographs of the surface and cross section of the coating layer show that clay tends to form dense coating structure, while GCC tends to form bulky coating layer.

• Journal of the Korean Society for Precision Engineering
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• 제15권12호
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• pp.106-112
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• 1998

A major problem in automation of turning operations is the difficulty in obtaining a sufficient and reliable chip control. The chip should be detected in order to provide a optimum chip control for unmanned turning operation. Using the difference of energy radiated from the chip, chip Patterns are estimated using pyrometer. From the initial output from the pyrometer, chips are identified according to the backpropagation algorithm developed in the research. The learning system developed in this work can be applied in real-time control of turning process with minor modification in drive system.