• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1200-1207
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• 2007

An experimental test is presented for photoelastic stress analysis around a crack tip in tensile loaded plate. The hybrid method coupling photoelastsic fringe inputs calculated by finite element method and complex variable formulations involving conformal mappings and analytical continuity is used to calculate full-field stress around the crack tip in uniaxially loaded, finite width tensile plate. In order to accurately compare calculated fringes with experimental ones, both actual and regenerated photoelastic fringe patterns are two times multiplied and sharpened by digital image processing. Regenerated fringes by hybrid method are quite comparable to actual fringes. The experimental results indicate that Mode I stress intensity factor analyzed by the hybrid method are accurate within three percent compared with ones obtained by empirical equation and finite element analysis.

• New & Renewable Energy
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• v.6 no.4
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• pp.50-60
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• 2010

With the development of wind industry, rated power of the wind turbine also increases gradually. Accordingly, size of the wind turbine tower is becoming larger. Tower base diameter of the 2MW wind turbine is about 4m. Larger tower is expected for 4MW or 5MW turbines. Due to limitation of transportation, new type of tower with smooth transportation and effective cost is needed. In this work, a hybrid tower consisting of steel and concrete is designed and analyzed. The optimum ratio of steel and concrete of the hybrid tower is calculated as well as the thickness of the concrete part. Different FE analysis including modal analysis, buckling analysis and static analysis are performed to check the design of hybrid tower comparing with the steel tower. Redesign is also expected after various analyses.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.16-23
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• 2003

In this paper, we propose a new optical hybrid switching system that takes advantage of both Optical Burst Switching (OBS) and Optical Circuit Switching (OCS) technologies. This system classifies incoming IP traffic flows into short-lived and long-lived flows for hybrid switching. For performance analysis, we model the system as a single server queue in a Markovian environment. The burst generation process is assumed to follow a two-state Markov Modulated Poisson Process (MMPP), and the service rate fluctuates based on the number of concurrent OCS sessions. Results of the mean delay and queue size for OBS bursts are derived.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.346-350
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• 2009

The cultivated radish (Raphanus sativus L.) is a major vegetable crop in the world wide and fast-growing species that grows inhabitats of six continents. It is very important to determine hybrid seed purity in the production of hybrid Brassica vegetable seeds to avoid unacceptable contamination with self-inbred (sib) seeds. The use of random amplified polymorphic DNA (RAPD) markers for evaluating seed purity in $F_2$-hybrid radish cultivars demonstrated. One hundred eighty seeds from the F1 male and female harvest were subsequently screened for seed purity using 13 primers. The 13 primers result in 17 cultivar-specific bands and 23 variable RAPD bands scored for cultivar. RAPD analysis of hybrid seeds from the harvest revealed 128 seeds tested except underdevelopment and decayed seeds were sibs. Especially, $F_2$ hybrids of radish, OPC13, OPD20 were presented clear hybrid bands. It maintains higher than average level of genetic diversity compared with their correspondent parents. RAPD amplification of DNA extracted from germinated individuals from the female harvest reveal that 10 of 208 seeds tested were self-inbred (4.8%). RAPD analysis of hybrid seeds from the male harvest revealed 7 of the 208 seeds tested were sibs (3.4%). The RAPD may lead to a better insight in to the hybrid seed purity.

• Earthquakes and Structures
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• v.13 no.3
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• pp.289-297
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• 2017

This paper presents seismic performance and reliability evaluation on steel-timber hybrid shear wall systems composed of steel moment resisting frames and infill light frame wood shear walls. Based on experimental observations, damage assessment was conducted to determine the appropriate damage-related performance objectives for the hybrid shear wall systems. Incremental time-history dynamic analyses were conducted to establish a database of seismic responses for the hybrid systems with various structural configurations. The associated reliability indices and failure probabilities were calculated by two reliability methods (i.e., fragility analysis and response surface method). Both methods yielded similar estimations of failure probabilities. This study indicated the greatly improved seismic performance of the steel-timber hybrid shear wall systems with stronger infill wood shear walls. From a probabilistic perspective, the presented results give some insights on quantifying the seismic performance of the hybrid system under different seismic hazard levels. The reliability-based approaches also serve as efficient tools to assess the performance-based seismic design methodology and calibration of relative code provisions for the proposed steel-timber hybrid shear wall systems.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.729-733
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• 2003

Hybrid RMU is a kind of power circuit breaker and protects electric devices from over-current. In this paper we built a dynamic model of RMU driving mechanism using ADAMS and performed a optimal design of several design parameters. Finally we developed a prototype of RMU driving mechanism through results of analysis and confirmed it to satisfy design requisitions.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.618-621
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• 2002

This paper proposes a static vu compensator using hybrid cascade 5-level PWM inverter, Circuit DQ transformation is used for modeling and analysis of the system, and it reveals the important characteristics and related equations of the system. Also, a multilevel PWM technique suitable to hybrid structure Is proposed for less harmonics in the input currents of the system. Finally, the validity of tile characteristics analysis is shown through PSIM simulations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.71-78
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• 2015

This paper presents a method for analyzing the size and economic sensitivity of a new renewable hybrid generation system according to changes in the component replacement costs based on HOMER (Hybrid Optimization Model for Electric Renewables). The design of a hybrid system can be optimized by reducing the size of a sensitive component based on sensitivity analysis using the change in cost of a component. Sensitivity analysis can also provide information on what combinations are necessary for the optimal hybrid system. As an example, sensitivity analysis was performed on the residential load provided by HOMER, and the effects of component replacement costs on the system size and cost were quantitatively analyzed.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.59-67
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• 2015

PURPOSES : In this study, an image analysis method is used to evaluate the pore structure characteristics and permeability of hybrid concrete. METHODS : The binder weight of hybrid concrete is set to $400kg/m^3$, $370kg/m^3$, and $350kg/m^3$, and for each value of binder weight, the pore structure and permeability of concrete mixture is evaluated. The permeability of hybrid concrete is evaluated using a rapid chloride penetration test(RCPT). RESULTS : The concrete pore structure characteristics of hybrid concrete reveals that as the binder weight is reduced, the entrained air is reduced and the entrapped air is increased. The permeability of the hybrid concrete for all values was measured to be below 1000 C, which indicates a "Very Low" level of permeability relative to the evaluation standard of KS F 2711. Additionally, as the binder weight is decreased, there is a significant increase in the permeability of chloride ions. CONCLUSIONS : In this study, the pore structure characteristics of hybrid concrete at different binder weights shows that as the binder weight is reduced, the entrained air is reduced and the entrapped air is increased. Consequently, chloride ion penetration resistance of the hybrid concrete is diminished. As a result, it is expected that this will reduce the concrete's durability.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1516-1523
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• 2003

An inverse radiation analysis is presented for the estimation of the boundary emissivities for an absorbing, emitting, and scattering media with diffusely emitting and reflecting opaque boundaries. The finite-volume method is employed to solve the radiative transfer equation for a two-dimensional irregular geometry. A hybrid genetic algorithm is proposed for improving the efficiency of the genetic algorithm and reducing the effects of genetic parameters on the performance of the genetic algorithm. After verifying the performance of the proposed hybrid genetic algorithm, it is applied to inverse radiation analysis in estimating the wall emissivities in a two-dimensional irregular medium when the measured temperatures are given at only four data positions. The effect of measurement errors on the estimation accuracy is examined.