• Title/Summary/Keyword: stability period

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Evaluation of Internal Settlement of Rockfill Dam under Construction (석괴댐의 축조 중 내부 침하 거동 평가)

  • Seo, Min-Woo;Kim, Yong-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.4
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    • pp.45-52
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    • 2010
  • The purposes of this research are to analyze the internal settlement behavior of Concrete Faced Rockfill Dam (CFRD) typed 'D dam' and to evaluate the stability of the 'D dam' during dam construction using internal settlement measurements and results of numerical analysis. The field measurements were obtained during dam construction period. The numerical analysis was also carried out for the same construction period. The numerical analysis focused mainly on prediction of stress and displacement behavior of 'D dam' during dam construction stage using input parameters obtained from laboratory tests, i.e. large triaxial tests. The behavior of 'D dam' was evaluated to be stable from comparing the results of field measurements and numerical analysis. A simple empirical equation is also presented to predict final settlement at the completion of dam construction, using settlement measurement monitored during dam embankment.

Full mouth rehabilitation with vertical dimension increase in patient with severely worn out dentition (과도한 마모를 가진 환자의 수직 고경 증가를 동반한 전악수복 증례)

  • Jung, Ji-Hye
    • The Journal of the Korean dental association
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    • v.54 no.6
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    • pp.438-446
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    • 2016
  • Severe tooth wear may cause the pathologic change of the TMJ and masticatory muscles, unesthetic facial appearance, pathogenic pulp and occlusal disharmony. Treating patients with severely worn dentition often requires full mouth rehabilitation with increasing vertical dimension. Proper diagnosis and treatment planning are important for esthetic and functional definitive restorations and the long term stability of the neuromuscular system and the TMJ. In this case, 66 year-old female presented with generalized worn dentition. Based on assessment, pathologic destruction of teeth structure on entire dentition was caused by masticatory force and diet habit without loss of vertical dimension. Subsequently, 3 mm increase of vertical dimension that based on incisor for tooth restoration and esthetic improvement was determined. After 8 weeks stabilization period with temporary fixed prostheses, definitive prostheses were fabricated. After 6 months follow up period, satisfactory outcomes were attained both functional and esthetic aspects through this procedure.

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Study of New Control Method for Linear Periodic System

  • Jo, Janghyen
    • 제어로봇시스템학회:학술대회논문집
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    • 1999.10a
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    • pp.83-87
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    • 1999
  • The purpose of this study is to provide the new method for selection of a close to optimal scalar control of linear time-periodic system. The case of scalar control is considered, the gain matrix being assumed to be at worst periodic with the system period T. The form of gain matrix may have various kinds but must have same period, for example, one of each element being represented by Fourier series. As the optimal gain matrix I consider the matrix ensuring the minimum value of the larger real part of the Poincare exponents of the system. Finally we present a pole placement algorithm to make the given system be stable. It is possible to determine the stability of the given periodic system without get the analytic solution. The application of the method does not require the construction of the Floquet solution. At present state of determination of the gain matrix for this case will be done only by systematic numerical search procedures.

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The Effect of Water Activity on the Storage Stability of Red Ginseng (수분활성도가 홍삼저장성에 미치는 영향)

  • 도재호;노해원
    • Journal of Ginseng Research
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    • v.5 no.2
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    • pp.108-113
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    • 1981
  • Major quality indices for deterioration of red ginseng including oxidation of lipids and change of brown color intensity were periodically investicated during storage of Red Ginseng under various water activity conditions at 3$0^{\circ}C$. The results obtained were summarized as follows. 1. The monolayer moisture contents were 3.25% and 6.3% for red ginseng and red ginseng powder, respectively, and the corresponding water activities were 0.14 and 0.16, respectively. 2. Oxidation of lipids as measured by TBA value increased with an increase in relative humidity and storage period 3. Under storage conditions above 42% R H., brown color intensity also increased in similar fashion to that of oxidation of lipids as relative humidity and storage Period increased 4. It was concluded from above results that water activity of Red Ginseng should be kept less than 0.57 so that red ginseng could Preserve stable qualify.

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Ocean Engineering Basic Test for 5MW Offshore Wind Turbine Sub-structure Jack-up Platform (5MW급 해상풍력 Sub-structure Jack-up Platform 수조모형시험)

  • Jeon, Jung-Do;Jeon, Eon-Chan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.1
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    • pp.15-21
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    • 2013
  • The safety and stability of 5MW class offshore wind turbine Jack-up platform was investigated through ocean basin experiment. For simulating the environmental condition of yellow sea in the South Korea, diverse waves, winds and currents were performed based on Froude's number. Regular wave and irregular wave based on Froude's number were applied to the wind turbine structure. In experiments, the height and period of regular wave type were scaled down as the 1:50 ratio of real wave condition. Irregular wave type was simulated with TMA(Texel Storm, Marsen and Arsloe)spectrum. The vertical reaction force, resonance period and wave pressure applied to multi-supporters of wind offshore structure were measured experimentally. Finally, the results showed that the capsizing situation of the offshore structure was generated by the severe environmental condition.

Observer Design of SRM for Position-Velocity Estimation (SRM의 위치-속도 추정을 위한 관측자 설계)

  • Lee, Tae-Gyoo;Kim, Jung-Tae;Huh, Uk-Youl
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.219-222
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    • 1994
  • This thesis describes an observer of Switched Reluctance Motor for position. velocity and torque estimation using current sening. Inductance of SRM varies trapezoidally with respect to the rotor position. This means that the inductance of each phase is a periodic function with the same period. Under this condition. the observer with a constant gain can be developed though SRM has nonlinear characteristics. Because SRM has equivalent physical meaning with each period. The stability of error system which is the difference between actual system and observer system. is analyzed using Lyapunov and variable structure theory. The effectiveness of the proposed estimation is shown by various simulation.

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The Precipitation Climate of South Korea and the Dichotomous Categorical Verification Indices (남한 강수 기후와 이분 범주 예보 검증 지수)

  • Lim, Gyu-Ho
    • Atmosphere
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    • v.29 no.5
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    • pp.615-626
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    • 2019
  • To find any effects of precipitation climate on the forecast verification methods, we processed the hourly records of precipitation over South Korea. We examined their relationship between the climate and the methods of verification. Precipitation is an intermittent process in South Korea, generally less than an hour or so. Percentile ratio of precipitation period against the entire period of the records is only 14% in the hourly amounts of precipitation. The value of the forecast verification indices heavily depends on the climate of rainfall. The direct comparison of the index values might force us to have a mistaken appraisal on the level of the forecast capability of a weather forecast center. The size of the samples for verification is not crucial as long as it is large enough to satisfy statistical stability. Our conclusion is still temporal rather than conclusive. We may need the amount of precipitation per minute for the confirmation of the present results.

A Design of SRM Controller using Microprocessor

  • Park, Joon-Hoon;Ahn, Jung-Soo;Han, Wun-Dong;Park, Boo-Chong
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.2023-2026
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    • 2002
  • This paper explains the study of controller design applied to SRM(Switched Reluctance Motor) concept. This controller executes controller algorithms via ${\mu}$-processor to increase stability and precise measurement, and VHDL (Very high speed integrated circuit Hardware Description Language) is designed to generate SRM driving signal. During initial period, SRM controller was designed to control .respective target RPM (Revolution per minutes) and PR (Proportional Integral Differential) coming from the PC(Personal Computer) monitor program, and receiving clockwise and counter-clockwise rotation signal and target RPM coming from the front panel, and receiving the location of rotational element and RPM generating from the position censor during activation period.

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Modifying Inappropriate Behaviors of Nursery School Children through Token and Social Reinforcement (토오컨강화와 사회적강화를 이용한 유아원 아동의 부적절한 학습행동의 수정)

  • Kim, Jin Sook
    • Korean Journal of Child Studies
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    • v.8 no.2
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    • pp.61-71
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    • 1987
  • The effects of token and social reinforcement on inappropriate study behaviors of nursery school children were investigated. The subjects were three nursery school boys, and the target behaviors were : 1) out-of-seat behaviors, 2) bothering other children, and 3) disruptive behaviors. The ABAB(Reversal) design was used in this experiment. It consisted of four periods : baseline, reinforcement I, reversal, and reinforcement II. During the reinforcement period, social reinforcement as well as token reinforcement was applied. In all three subjects, inappropriate study behaviors decreased during the reinforcement periods (I, II), and increased during the reversal period, showing the effects of token and social reinforcement. The subjects showed stability in three post-experimental tests, indicating that modification of inappropriate study behaviors was being maintained.

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A Preliminary Experiment Study for Development of Floater of Floating Breakwater (부소파제의 부체 개발을 위한 기초적 실험연구)

  • JUNG DONG-HO;KIM HYOUN-JOO;KIM JIN-HA;MOON DEOK-SU
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.11a
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    • pp.102-107
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    • 2004
  • New designed floating breakwater made of Polyethelener with considering the introduction of new material for being harmony with environment and stability of the floater is developed for a marine ranching. Model experiment in order to test its capability is performed for the regular and irregular waves in ocean engineering basin. Good capability to break the incident wave within the 6 second of period and 1 m of height is shown. Breaking efficiency for long period wave is not so good in regular and irregular wave. The results of this study will contribute to the design and construction of the floating breakwater.

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