• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.315-323
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• 2015

The weld scallop has been used for joining T-bars. There are a lot of weld scallops in shipbuilding. It is difficult to perform scallop welding due to the inconvenient welding position. This results in many problems such as porosity, slag inclusion, etc. In this study, a new method is devised to remove weld scallops by incorporating a Ceramic Backing Material (CBM). The weld scallop is removed by an elongation of the v groove. In order to insert a CBM into the groove without a weld scallop, a wedge-shaped CBM is developed. The top side of the developed CBM is similar to the shape of a general back bead. The bottom surface has a saw-toothed shape for cutting at a suitable length. This can be attached to the root side of a face plate using adhesive tape, just like a general CBM. Welding experiments in normal and abnormal conditions are carried out and the possibility of burn-through is examined. This CBM's applicability to shipbuilding is verified.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.1
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• pp.35-41
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• 2017

We propose a face recognition and notification system that can transform visual face information into tactile signals in order to help visually impaired people. The proposed system consists of a glasses type camera, a mobile computer and an electronic cane. The glasses type camera captures the frontal view of the user, and sends this image to mobile computer. The mobile computer starts to search for human's face in the image when obstacles are detected by ultrasonic sensors. In a case that human's face is detected, the mobile computer identifies detected face. At this time, Adaboost and compressive sensing are used as a detector and a classifier, respectively. After the identification procedures of the detected face, the identified face information is sent to controller attached to a cane using a Bluetooth communication. The controller generates motor control signals using Pulse Width Modulation (PWM) according to the recognized face labels. The vibration motor generates vibration patterns to inform the visually impaired person of the face recognition result. The experimental results of face recognition and notification system show that proposed system is helpful for visually impaired people by providing person identification results in front of him/her.

• Journal of ILASS-Korea
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• v.19 no.2
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• pp.69-74
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• 2014

The comparison of the flow characteristics between circular and swirl jets which were controlled by the spinner attachment inside the airtube were conducted in this study. Swirl jet means a flow in whirls by mixing the flow of axial and tangential direction. Swirl flow has been used for the improvement of the combustion efficiency in the combustor. This flow is controlled by the spinner which has several vanes inclined by certain angles to the axial direction. In this study, angle of vane $30^{\circ}$ and diameter ratio of outlet to inlet of the airtube 0.73 were made. These spec. should find on the general gun type burner built in the domestic small size boiler. As the flow characteristics, axial and tangential velocities were measured by using the 2-D hot-wire velocimeter system and analyzed statistically. And also this research conducted a practical experiment considering to the attached belongings likes as ignitor, nozzle etc. on the airtube of the gun type burner. As a result, swirl occurred at the occasion of beingness and flow region extended considerably toward the radial direction. But effect of swirl did not transmit to the downstream. And the complicated flow was appeared regardless of the existence of spinner because of the effect of belongings.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.15-22
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• 2004

Static and dynamic analyses of a very flexible and light riser, for upwelling the deep ocean water, is performed. In this numerical study, an implicit finite difference algorithm is employed for three-dimensional riser equations. Fluid non-linearity and bending stiffness are considered and solved, using the Newton-Raphson iteration. Maintaining the depth of end point of a flexible and light riser is very important for upwelling deep ocean water in a floating type development system. Weight is attached at the end point of the riser in order to maintain its intake depth. It is designed under the strong surface current and the configuration of the rise is predicted. In the dynamic analysis, the tension variation at the top point of the riser is presented. T e results of this study can contribute to the design of the development system in floating type for upwelling deep ocean water.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2046-2048
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• 2005

This paper deals with ground potential rise of structure grounding electrode when a test current flows through grounding electrode. In order to analyze the potential gradient of ground surface on structure grounding electrode, the reduced scale model has been used. The structures were designed through reducing real buildings and fabricated with four types on a scale of one-one hundred sixty. The supporter was made to put up with weight of structure and could move into vertical, horizontal, rotary direction. When a test current flowed through structure grounding electrodes, ground potential rise was the lowest value at electric cage type(type B). According to resistivity and absorption percentage in concrete attached to structure, the potential distribution of ground surface appeared differently.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.859-865
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• 2008

Bacterial glycosyltransferases have drawn growing attention as economical enzymes for oligosaccharide synthesis, with their easy expression and relatively broad substrate specificity. Here, we characterized a glycosyltransferase homolog (Fnu_GT) from a human oral pathogen, Fusobacterium nucleatum. Bioinformatic analysis showed that Fnu_GT belongs to the glycosyltransferases family II. The recombinant Fnu_GT (rFnu_GT) expressed in Escherichia coli displayed the highest glycosylation activity when UDP-galactose (Gal) was used as a donor nucleotide-sugar with heptose or N-acetylglucosamine (GlcNAc) as an acceptor sugar. Interestingly, rFnu_GT transferred the galactose moiety of UDP-Gal to a nonreducing terminal GlcNAc attached to the trimannosyl core glycan, indicating its potential as an enzyme for human-type N-glycan synthesis.

• Journal of Korea Foundry Society
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• v.17 no.5
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• pp.480-487
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• 1997

Particle reinforced metal matrix composites(MMCs) via a centrifugal spray-cast deposition(CSD) process were fabricated by injecting second phase particles($Al_2O_3$<40${\mu}m$, W<17.3${\mu}m$) into copper melt on the atomizing disc. Compositing modes were investigated by combining microstructures and mathematical modeling between Cu droplets and the reinforced particles injected. The $Cu/W_P$ powders were shown that the W particles penetrate and get embedded in the Cu droplets. It is considered that the W particles composite preferentially in Cu melt on the atomizing disc. On the other hand, the $Al_2O_3$, particles did not penetrate into the Cu droplets on the atomizing disc but get attached in surface of Cu droplets during the flight. It is considered that the compositing may be attained in the flight distance which the relative velocity between Cu droplet and $Al_2O_3$, particle is maximum. The microstructure of the $Cu/W_P$ and the $Cu/(Al_2O_3)_p$ composite preform was strongly influenced by compositing modes of droplets, and after subsequent deposition it was comprised as it is called the dispersed type and the cell type of microstructure, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.113-118
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• 2000

Centrifugal pump are widely used and the noise generated by these machines causes one of the most serious problems. In general, the centrifugal pump noise is often dominated by tones at BPF(blade passage frequency) and its higher harmonics. This is a consequence of the strong interaction between the flow discharged from the impeller and the cutoff in the casing. However, only a few researches have been carried out on predicting the noise because of the difficulty in obtaining detailed information about the flow field and casing effects on noise radiation. The objective of this study is to develop a prediction method for the unsteady flow field and the acoustic pressure field of a centrifugal pump, and to calculate the effects of small vanes that are attached in original impeller-splitter impeller. We assume that the impeller rotates with a constant angular velocity and the flow field around the impeller is incompressible and inviscid. So, a discrete vortex method(DVM) is used to model the centrifugal pump and to calculate the flow field. The force of each element on the blade is calculated by the unsteady Bernoulli equation. Lowson's method is used to predict the acoustic source. The splitter impeller changes the acoustic characteristics as well as performance. Two-splitter type impeller is good for acoustic characteristics.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.1-6
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• 2013

A 25ft class fishing leisure boat is developed, and the resistance performances are investigated by a model test in a high-speed circulating water channel. The design speed of the developed ship is 25 knots using a 150 ps outboard engine. A catamanan type hull form using a planing section is adopted considering the Froude number and large deck area. The effect of a center body attached on the bottom of the cross deck is studied under various conditions. Wave patterns are observed to make clear the relationship between the resistance performance and the wave characteristics. The results show that the shape of the center body and the position of the chine line can have a strong effect on the resistance performance in a certain velocity range.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.45-52
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• 2019

In this study, the seismic strengthening technique considering the rocking behavior of the wall was developed. The rocking system rotates left and right around the vertical axis of the wall. The development system is a method of dissipating energy by installing a damper which was attached at a large displacement portion. The damper was made of a steel material, and the shape and height of the strut were selected as variables. Experimental results showed that in case of shorter strut make strength capacity increasement and in case of longer strut make deformation capacity increasement. As a result of comparing the abilities according to I and S type strut shapes, it was evaluated that S type has better seismic performance.