• Journal of Electrical Engineering and Technology
• /
• v.2 no.3
• /
• pp.373-378
• /
• 2007

Soft switching was applied to the multi-level inverter to enhance the performance of the high-intensity discharge (HID) ballast used in vehicle headlights. The electrical properties were investigated and the available modeling of ballast in steady state was calculated using mathematical methods. The result was used in analyzing the power characteristics. The modeling was confirmed by the experiment.

• Proceedings of the Korean Fiber Society Conference
• /
• 1998.10a
• /
• pp.98-101
• /
• 1998

Segmented polyurethane elastomers are an important class of polymeric materials consisting of thermodynamically incompatible hard and soft segments. Due to the chemical structural difference between the hard and soft segments, a microphase separation occurs, consisting of crystalline hard domains and amorphous soft domains. (omitted)

• Textile Coloration and Finishing
• /
• v.22 no.4
• /
• pp.332-340
• /
• 2010

Nowadays natural textile materials should cope with the global warming. Soft, thin and light angora fibers which have two components. One is spiky hair and the other is soft hair. The spiky hairs have a disadvantage of pilling out. The soft hairs have promising properties comparable to cashmere goat hairs, which is cheap compared to very expensive cashmere goat hairs. In this study, we investigated the dyeing properties of angora/PET, Nylon blend fabrics to acid dyes and reactive dyes including various series of acid dyes and reactive dyes for the dyeing of the blended super soft angora fabrics and their potential for deep shade dyeing effects. Our focus is to get a relation between various kind of blend and their dyeability.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.964-968
• /
• 2010

Ground anchor, commonly referred to as tiebacks or tie-down, is essentially steel elements secured in the ground by cement grout. They are used to provide either lateral or vertical support for various engineered structures, and are effective in all types of soil and rock. However, ground anchor can not be used in soft clay because anchor resistance would not be guaranteed. In this paper, conceptual introduction of the Smart Anchor is presented. The Smart Anchor is a kind of friction type anchor, the load is diffused and applied to the various parts of the distributed bond length, having less impact on the grout strength, and being able to secure necessary anchoring force in relatively soft grounds. This study shows a numerical study of predicting the load transfer of The Smart Anchor in soft clay. A beam-column analysis was performed by a elastic-plastic P-y curves in soft clay.

• Computers and Concrete
• /
• v.25 no.1
• /
• pp.83-94
• /
• 2020

The use of fly ash in modern-day concrete technology aiming sustainable constructions is on rapid rise. Fly ash, a spinoff from coal calcined thermal power plants with pozzolanic properties is used for cement replacement in concrete. Fly ash concrete is cost effective, which modifies and improves the fresh and hardened properties of concrete and additionally addresses the disposal and storage issues of fly ash. Soft computing techniques have gained attention in the civil engineering field which addresses the drawbacks of classical experimental and computational methods of determining the concrete compressive strength with varying percentages of fly ash. In this study, models based on soft computing techniques employed for the prediction of the compressive strengths of fly ash concrete are collected from literature. They are classified in a categorical way of concrete strengths such as control concrete, high strength concrete, high performance concrete, self-compacting concrete, and other concretes pertaining to the soft computing techniques usage. The performance of models in terms of statistical measures such as mean square error, root mean square error, coefficient of correlation, etc. has shown that soft computing techniques have potential applications for predicting the fly ash concrete compressive strengths.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.2
• /
• pp.88-93
• /
• 2016

Soft starters are used with large induction motors in blowers, fans, pumps and the crane hoist drives. AC voltage controllers are used as soft starters in induction motors for starting and to adjust its speed. Soft-starter starting system uses phase control method of input electric source through the setting of the thyristor(SCR) firing angle ${\alpha}$, and it can control input electric source stably and continuously from beginning of starting to ending of starting. In this paper, it is verified that power stack of high-voltage with SCR series system possesses dielectric strength and input electric source is controlled stably by phase control. Especially, from the driving experimental of proposed soft-starter operating, a smoothing acceleration and inrush current decrease can be achieved by the series SCR trigger.

• Journal of Power Electronics
• /
• v.2 no.4
• /
• pp.288-296
• /
• 2002

In this paper, a high frequency transformer - assisted auxiliary active resonant commutated snubber (HFTA-ARCS) for voltage source soft switching pulse width modulated power conversion circuits is presented. A three phase voltage source type soft switching inverter incorporating HFTA-ARCS circuits in its three bridge legs can reduce current rating of auxiliary active power switches and has sensorless simplified control scheme which any specified boost current management is not required for soft switching. Its operation principle and digital control scheme are described and a practical design method of circuit parameters on this HFTA-ARCS circuit is also introduced on the basis of computer simulation. Moreover, this space voltage vector modulated soft switching inverter system with DSP-based digital control scheme Is discussed and its effectiveness is proved on the basis of performance evaluations. The operating performances of this inverter system are also compared with those of conventional three-phase hard switching inverter under practical conditions of specified parameters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.12
• /
• pp.871-876
• /
• 2014

Efficiency of crystalline Si solar cell can be maximized as minimizing optical loss through antireflection texturing with inverted pyramids. Even if cost-competitive, soft lithography can be employed instead of photolithography for the purpose, some limitations still remain to apply the soft lithography directly to as-received solar grade wafer with a bunch of micro trenches on surface. Therefore, it is needed to develop a low-cost, effective planarization process and evaluate its output to be applicable to patterning process with PDMS stamp. In this study new surface planarization process is proposed and the change of micro scale trenches on the surface as a function of etching time is observed. Also, the effect of trenches on pattern quality by soft lithography is investigated using FEM structural analysis. In conclusion it is clear that the geometry and shape of trenches would be basic considerations for soft lithography application to low quality wafer.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.522-525
• /
• 2005

The purpose of this study was to analyze the pattern of muscle usage during swing motion with a soft golf club in comparison with that with a normal golf club. The subjects were normal healthy young adults. The subjects performed swing motion using normal and soft golf clubs in turn. Then, we compared and analyzed the muscular activities for the two cases. The muscular activities of the subject was measured using MP100(BIOPAC Systems, Inc.). For the analysis of muscular activities, we measured EMG(Electromyography) of the subjects during swing motion. The muscles analyzed were deltoid, latissimus dorsi, external oblique, and rectus abdominis of the upper limbs and rectus femoris, biceps femoris, gastrocnemius, and soleus of the lower limbs. The result of the experiment showed that the pattern of muscle usage with soft golf club was similar to that with a normal golf club but the muscular activities with the soft golf was smaller than that with the normal golf club.

• Journal of Biomedical Engineering Research
• /
• v.26 no.1
• /
• pp.55-63
• /
• 2005

A novel imaging system for High-resolution Ultrasonic Transmission Tomography (HUTT) and soft tissue differentiation methodology for the HUTT system are presented. The critical innovation of the HUTT system includes the use of sub-millimeter transducer elements for both transmitter and receiver arrays and multi-band analysis of the first-arrival pulse. The first-arrival pulse is detected and extracted from the received signal (i.e., snippet) at each azimuthal and angular location of a mechanical tomographic scanner in transmission mode. Each extracted snippet is processed to yield a multi-spectral vector of attenuation values at multiple frequency bands. These vectors form a 3-D sinogram representing a multi-spectral augmentation of the conventional 2-D sinogram. A filtered backprojection algorithm is used to reconstruct a stack of multi-spectral images for each 2-D tomographic slice that allow tissue characterization. A novel methodology for soft tissue differentiation using spectral target detection is presented. The representative 2-D and 3-D HUTT images formed at various frequency bands demonstrate the high-resolution capability of the system. It is shown that spherical objects with diameter down to 0.3㎜ can be detected. In addition, the results of soft tissue differentiation and characterization demonstrate the feasibility of quantitative soft tissue analysis for possible detection of lesions or cancerous tissue.