• Geomechanics and Engineering
• /
• v.28 no.1
• /
• pp.77-87
• /
• 2022

Many geotechnical analyses require the investigation of water flow within partially saturated soil zone to incorporate the effect of climatic conditions. It is widely understood that the hydraulic properties of the partially saturated soil should be included in the transient seepage analyses. However, the characteristics of dual porosity soils with dual-mode water retention curve are normally modelled using single-mode mathematical equation for simplification of the analysis. In reality, the rainwater flow can be affected significantly by the dual-mode hydraulic properties of the soil. This paper presents the variations of safety factor for dual porosity soil slope with dual-mode water retention curve and dual-mode unsaturated permeability. This paper includes the development of the new dual-mode unsaturated permeability to represent the characteristics of soil with the dual-mode water retention curve. The finite element analyses were conducted to examine the role of dual-mode water retention curve and dual-mode unsaturated permeability on the variations of safety factor under rainfall loading. The results indicate that the safety factor variations of dual porosity soil slope modelled using the dual-mode water retention curve and the unsaturated permeability equation are lower than those of dual porosity slope modelled using single-mode water retention curve and unsaturated permeability equations.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.444-446
• /
• 2011

A bidirectional dual active converter with the power factor control capability is proposed as a battery charger. The source side half-bridge acts as a PWM converter that maintains the unity power factor. The battery side half-bridge converter acts as a dual active bridge (DAB) together shares the same DC link voltage with PWM converter. The imbalance voltage phenomenon is eliminated by employing asymmetric duty cycle technique. Simulation results are included to verify theoretical analysis.

• Steel and Composite Structures
• /
• v.14 no.6
• /
• pp.621-636
• /
• 2013

Response modification factor is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake, in conformity with the point that many seismic design codes led to reduce the loads. In the present paper it's tried to evaluate the response modification factors of dual moment resistant frame with buckling restrained braced (BRB). Since, the response modification factor depends on ductility and overstrength; the nonlinear static analysis, nonlinear dynamic analysis and linear dynamic analysis have been done on building models including multi-floors and different brace configurations (chevron V, invert V, diagonal and X bracing). The response modification factor for each of the BRBF dual systems has been determined separately, and the tentative value of 10.47 has been suggested for allowable stress design method. It is also included that the ductility, overstrength and response modification factors for all of the models were decreased when the height of the building was increased.

• Proceedings of the KIEE Conference
• /
• 1988.11a
• /
• pp.385-387
• /
• 1988

Dual converter is being used as a four-quadrant source for the controlled rectifier. But the rectifier itself and circulating current between P and N-converter contribute to generate reactive power. The methodology of input power factor control of dual converter by means of circulating current control is presented in this paper.

• Journal of Families and Better Life
• /
• v.21 no.2
• /
• pp.213-220
• /
• 2003

In this study, I analyzed dual-career commuting couples time use. Concretely, this study compared the husband with the wife on the becoming a commuter family, the living apart on weekdays. And it examined time use on weekdays and weekends by the time amount of each activities and the ratio of actor on each hour. The survey participants included 131 married people who were dual-career commuting couple and who were maintained separate residence and work place. The major findings are as follows: First, weekday separation of the dual-career commuting couples is largely due to career. This kind separation is mostly due to sociostructural labor market factor and individual factor to increasing working women. Second, 94.6%(53) of male participants were resident living apart from their family on weekdays. Third, the most wives mentioned some kind of emotional liberation such as freedom on weekdays. Finally, there was gender difference in the time spent on each activities when dual-career commuting couples are living together and they are apart. Especially the most gender difference on weekdays is household work time and leisure time.

• Structural Engineering and Mechanics
• /
• v.69 no.6
• /
• pp.591-605
• /
• 2019

Investigations on seismic performance of eccentrically braced frames equipped with dual vertical links have received little attention. Therefore, the main goal of this paper is to describe design steps for such frames and evaluate nonlinear performance of this system according to the reliability analysis. In this study, four and eight story frame structures are analyzed and the response modification factors for different intensity and damage levels are derived in a matrix form based on a new approach. According to the obtained results, the system has high ductility and acceptable seismic performance. Moreover, it is concluded that using response modification factor equal to 8 in the design of system provides desirable seismic reliability under the design and maximum probable hazard levels. Due to desirable performance and significant advantages of the dual vertical links, this system can be used as a main lateral load bearing system, in addition to its application for rehabilitation of damaged structures.

• Journal of Power Electronics
• /
• v.10 no.3
• /
• pp.293-299
• /
• 2010

In this paper, a single-phase PFC (Power Factor Correction) dual boost converter based on input voltage estimation is studied for DC inverter air conditioner. It is focused on improving input power factor and power quality to satisfy the recent harmonic current regulation standards. Furthermore the input voltage estimation is introduced for price competitive products. A low cost and reasonable control system is implemented using a specified high-speed 32-bit microprocessor. Their effectiveness are verified through theoretical analysis and experiments.

• Computational Structural Engineering : An International Journal
• /
• v.1 no.2
• /
• pp.137-137
• /
• 2001

The reliability/redundancy of structural system has become a serious concern among engineers and researchers after structural failures in Northridge and Kobe earthquakes. The reliability/redundancy factor, ρ, in current codes considers only member force and floor area and has received much criticism from dissatisfied engineers. Within a reliability framework. the redundancy is investigated for dual systems of primary shear walls and secondary moment frames and steel moment frame systems. Probabilistic performance analyses are carried out baled on nonlinear responses under SAC ground motion. The effects of structural configuration, ductilily capacity, 3-D motion, and uncertainty of demand verses capacity are investigated. Important redundancy-contributing factors are identified and a uniform-risk redundancy factor is developed for design. The result are compared with the p factor and its inconsistency is pointed out.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.1
• /
• pp.92-97
• /
• 2008

In this Paper, we present a scaling theory for dual material surrounding gate (DMSGTs) MOSFETs, which gives a guidance for the device design and maintaining a precise subthreshold factor for given device parameters. By studying the subthreshold conducting phenomenon of DMSGTs, the effective conductive path effect (ECPE) is employed to acquire the natural length to guide the design. With ECPE, the minimum channel potential is used to monitor the subthreshold behavior. The effect of ECPE on scaling factor significantly improves the subthreshold swing compared to conventional scaling rule. This proposed model offers the basic designing guidance for dual material surrounding gate MOSFETs.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.2
• /
• pp.134-141
• /
• 2022

This study presents a method for reducing current distortion that occurs when a dual-buck inverter generates reactive power. Dual-buck inverters, which are only capable of unity power factor operation, can generate reactive power capabilities by modifying a modulation technique. However, under non-unity power factor conditions, current distortion occurs at zero-crossing points of grid voltage and output current. This distortion is caused by parasitic capacitors, dead-time, and discontinuous conduction mode operation. This study proposes a modified modulation method to alleviate the current distortion at zero-crossing point of the grid voltage. A repetitive controller is applied to reduce this distortion of the output current. A 1 kVA prototype is built and tested. Simulation and experimental results demonstrate the effectiveness of the proposed method.