• Computers and Concrete
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• v.30 no.4
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• pp.277-287
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• 2022

Due to the scarcity of extortionate experimental data, fatigue failure of the reinforced concrete (RC) element might be achieved economically adopting nonlinear finite element (FE) analysis as an alternative approach. However, conventional implicit dynamic analysis is expensive, quasi-static method overlooks interaction effects and inertia, direct cyclic analysis computes stabilized responses. Apart from this, explicit dynamic analysis may provide a numerical operating system for factual long-term responses. The study explores the fatigue behavior based on a simplified explicit dynamic solution employing nonlinear time domain analysis. Among fourteen RC beams, one beam is selected to validate under static loading, one under fatigue with the experimental study and other twelve to check the detail fatigue behavior. The SWOT (Strength, Weakness, Opportunities, Threats) analysis has been carried out to pinpoint the detail scenario in the adoption of numerical approach as an alternative to the experimental study. Excellent agreement of FE and experimental results is seen. The 3D nonlinear RC beam model at service fatigue limits is truthful to be used as an expedient contrivance to envisage the precise fatigue behavior. The simplified analysis approach for RC beam under fatigue offers savings in computation to predict responses providing acceptable accuracy rather than the complicated laboratory investigation. At higher frequency, the flexural failure occurs a bit earlier gradually compared to the repeated loading case of lower frequency. The deflection increases by 6%-10% at the end of first cycle for beams with increasing frequency of cyclic loading. However, at the end of fatigue loading, greater deflection occur earlier for higher load range because of more rapid stiffness degradation. For higher frequency, a slight boost in concrete compressive strains at an initial stage of loading has been seen indicating somewhat stepper increment. Stiffness degradation in larger loading cycle at same duration escalates the upsurge of the rate of strain in case of higher frequency.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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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.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.341-348
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• 1985

This study aims at analysis hog cycles and seasonal price patterns, and at develop the procedure for price forecasting based on the relative price ratios by farmers. Seasonal price patterns have been a persistent feature of hog markets. Some month have historically high price and other months historically low price. Hog price tend to be high in Feb, May, June, Sept, winter (Nov. to Jan.) and tend to be low in the other months. There have been four price cycles for 12 years, 1972-1984, the length of the hog price cycle has varied from 24 month to 42 months, with the irregular frequency. The increasing period of the price cycle lasted 23 months and the decreasing period of the price cycle lasted 13 months. Tables 2, 3, 4 in this study show average hog price ratios and the number of times price fall, rose for one, two, and three months ahead of each calendar month.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1133-1138
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• 2007

DLLs(Delay Locked Loops) have widely been used in many systems in order to achieve the clock synchronization. A SMD (Synchronous Mirror Delay) structure is used both for skew reduction and for DCC (Duty Cycle Correction). In this paper, a SMD based DLL with DCC using Reduced Delay Lines is proposed in order to reduce the clock skew and correct the duty cycle. The merged structure allows the forward delay array to be shared between the DLL and the DCC, and yields a 25% saving in the number of the required delay cells. The designed chip was fabricated using a $0.25{\mu}m$ 1-poly, 4-metal CMOS process. Measurement results showed the 3% duty cycle error when the input signal ranges from 80% to 20% and the clock frequency ranges from 400MHz to 600MHz. The locking operation needs 3 clock and duty correction requires only 5 clock cycles as feature with SMD structure.

• Journal of the Korean housing association
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• v.12 no.4
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• pp.43-52
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• 2001

The purpose of this study is to fined out the characteristics of using & change of the residential space according to the children age and family life cycle. The results of this study are as follows: The first, as children grow up, children's activity space changed from living room to the private room, and housing condition was related to the frequency of each activity. The second, as children grow up, family's sleeping pattern changed, and this change effected the number of private rooms for sleeping and the use of the extra room. The third, changes of the using of dwelling space come out several pattern, increasing bedroom number through reconstruction, exchange of An-band and children room, parents' sleeping space move to living room, and change the function of rooms. The change pattern of the correspondence to the housing needs differed from each family life cycle stage.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.10
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• pp.141-151
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• 1994

this paper describes the design and implementation of a RISC processor for embedded control systems. This RISC processor integrates a register file, a pipelined execution unit, a FPU interface, a memory interface, and an instruction prefetcher. Its characteristics include both single cycle executions of most instructions in a 2 phase 20 MHz frequency and the worst case interrupt latency of 7 cycles with the vectored interrupt handling that makes it possible to be applicable to the real time processing system. For efficient handling of multi-cycle instructions, data stationary hardwired control scheme equippedwith cycle counter was used. This chip integrates about 139K transistors and occupies 9.1mm$\times$9.1mm in a 1.0um DLM CMOS technology. The power dissipation is 0.8 Watts from a 5V supply at 20 MHz operation.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.165-172
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• 1995

Many algorithms to enhance a speed performance of a robot have been studied, but it's rare to consider disign aspect of a robot arm for time optimal problem. In this paper, section demensions of a robot arm and a velocity profile of an end-effector were optimally designed to minimize the cycle time. Capacity of actuators, deflections of end-effector, and a fundamental natural frequency of the robot arm were constrained in optimal design. For a given path with a trapezoidal velocity profile, torques of each joint were calculated using the inverse kinematics and dynamics. For the SCARA type robot which is mainly used for assembly tasks, the time optimal design of each robot arm id presented with the above constraints.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.61-67
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• 2001

비대칭 펄스 직류 반응성 스퍼터링을 이용하여 상온에서 Si(100) 기판 위에 AlN 박막을 증착하였다. 100 kHz에서 200 kHz까지 펄스 주파수의 변화 및 70%에서 90%까지 duty cycle의 변화에 따른 아크 발생과 AlN 박막의 결정성 그리고 미세 조직을 관찰하였다. Duty cycle에서 양의 펄스 유지 시간이 증가함에 따라 증착 중에 아크 발생 빈도가 현저히 감소하였고 AlN 박막의 입자 크기와 결정상의 c축 배향성이 증가하였다. 반면에 펄스 주파수 변화에 따른 아크 발생은 일정한 경향을 나타내지 않았지만 전반적으로 많은 아크가 발생했다. 아크 발생 빈도가 늘어남에 따라 c축 배향성이 감소하였다. 양의 펄스 유지 시간과 펄스 주파수가 감소함에 따라 박막의 증착 속도는 증가하였으며 440$\AA$/min의 높은 증착 속도를 나타냈다.

• BMB Reports
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• v.53 no.7
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• pp.367-372
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• 2020

Cell cycle-related kinase (CCRK) has a conserved role in ciliogenesis, and Ccrk defects in mice lead to developmental defects, including exencephaly, preaxial polydactyly, skeletal abnormalities, retinal degeneration, and polycystic kidney. Here, we found that Ccrk is highly expressed in mouse trachea and bronchioles. Ccrk mutants exhibited pulmonary hypoplasia and abnormal branching morphogenesis in respiratory organ development. Furthermore, we demonstrated that Ccrk mutant lungs exhibit not only impaired branching morphogenesis but also a significant sacculation deficiency in alveoli associated with reduced epithelial progenitor cell proliferation. In pseudoglandular stages, Ccrk mutant lungs showed a downregulation of Hedgehog (Hh) signaling and defects in cilia morphology and frequency during progenitor-cell proliferation. Interestingly, we observed that activation of the Hh signaling pathway by small-molecule smoothened agonist (SAG) partially rescued bud morphology during branch bifurcation in explants from Ccrk mutant lungs. Therefore, CCRK properly regulates respiratory airway architecture in part through Hh-signal transduction and ciliogenesis.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.19-23
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• 2010

Life cycle and secondary production of Nymphs of Nemoura gemma Ham and Lee were estimated by using specimens collected from a stream in Mt. Jumbong in the central Korean peninsula. N. gemma in the study stream was univoltine. Youngest nymphs were collected in April. They appeared to grow continuously until the emergence in early spring next year. The cohort production interval for the species was estimated as 399 days. The annual secondary production (ash free dry weight) estimated by removal-summation and the size-frequency methods were 582 and $786\;mg\;m^{-2}\;yr^{-1}$, respectively. Gut content analysis showed that N. gemma was a shredder.