• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.1 s.29
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• pp.43-47
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• 1989

The microstructural changes of nylon 6 UDY, POY and FDY were compared after free-annealing through crystallinity, birefringence, and melting behavior analyses. Free-annealing was done at various temperatures $(120^{\circ}C\;,140^{\circ}C,\;160^{\circ}C,\;180^{\circ}C,\;200^{\circ}C)$ and times (15 min., 30 min., 60 min.) using vaccum oven. Crystallinity was measured by the density gradient column technique and birefringence was measured using a Nikon polarizing microscope with a quartz wedge and Senarmont compensator. Melting behavior was investigated on the basis of DSC melting corves. Crystallinites of specimens increased as the treatment temperature and time increased. Birefringence of UDY increased after annealing and increased as the treatment temperature increased. On the other hand, those of POY and FDY decreased after annealing. Especially, the changes of crystallinity and birefringence of treated POY were particularly lower than those of treated UDY and FDY. Melting peaks of untreated UDY, POY and FDY were different in the position and the shape, but little change was seen in melting peaks in spite of increasing the annealing temperature and time. UDY and FDY showed single melting peaks in all the specimens. But POY showed double melting peaks, which means the coexistences of crystals with different thermal properties.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.645-652
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• 1994

The leading edge of a turbine blade was simulated as a circular cylindrical surface. The effect of free-stream turbulence on the mass transfer upstream of the injectionhole has been investigated experimentally. The effects of injection location, blowing ratio on the Sherwood number distribution were examined as well. The mass transfer coefficients were measured by a naphthalene sublimation technique. The free-stream Reynolds number based on the cylinder diameter is 53,000. Other conditions investigated are: free-stream turbulence intensities of 3.9% and 8.0%, injection locations of $40^{\circ}$, $50^{\circ}$, and $60^{\circ}$ from the front stagnation point of the cylinder, and blowing ratios of 0.5 and 1.0. The role of the horseshoe vortex formed upstream edge of the injected jet is dicussed in detail. When the blowing ratio is unity, and the coolant jet is injected at $40^{\circ}$, the mass transfer upstream of the jet is not affected by the coolant jet at all. On the other hand, when the injection hole is located beyond $50^{\circ}$, the mass transfer upstream edge of the injection hole suddenly increases due to the formation of the horseshoe vortex, but it dereases as the free-stream turbulence intensity increases because the strength of the horseshoe vortex structure becomes weakened. The role of the horseshoe vortex is clearly evidenced by placing a rigid rod at the injection hole instead of issuing the jet. In the case of the rigid rod, the spanwise Sherwood number upstream of the injection hole is much larger due to the intense influence of the horseshoe vortex.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.131-136
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• 1997

We present a method to estimate a dense and sharp depth map using multiple cameras for the application to flexible video production. A key issue for obtaining sharp depth map is how to overcome the harmful influence of occlusion. Thus, we first propose to selectively use the depth information from multiple cameras. With a simple sort and discard technique, we resolve the occlusion problem considerably at a slight sacrifice of noise tolerance. However, boundary overreach of more textured area to less textured area at object boundaries still remains to be solved. We observed that the amount of boundary overreach is less than half the size of the matching window and, unlike usual stereo matching, the boundary overreach with the proposed occlusion-overcoming method shows very abrupt transition. Based on these observations, we propose a hierarchical estimation scheme that attempts to reduce boundary overreach such that edges of the depth map coincide with object boundaries on the one hand, and to reduce noisy estimates due to insufficient size of matching window on the other hand. We show the hierarchical method can produce a sharp depth map for a variety of images.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.296-300
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• 2018

Penile shaft reconstruction requires adequate soft tissue characteristics as well as constant vascular pedicles when considering a perforator flap. The free flap technique using various donor sites and regional conventional and perforator flaps have been utilized for penile shaft reconstruction. Still, the free flap techniques include challenging surgical procedures in addition to postoperative management. The regional flap can be applied to limited defects due to the size and shape. We performed the bilateral superficial external pudendal artery (SEPA) perforator flaps in order to reconstruct a circumferential penile shaft defect. The circumferential wound has noted necrotic tissue involving superficial (Dartos) fascia. We underwent debridement, preserving deep (Buck's) fascia and corpus spongiosum. Thereafter, the soft tissue defect was covered with bilateral SEPA perforator flaps. The patient has been observed for 27 months, showing penile resilience without deformity or wound-related problems.

• Journal of the Korean Society of Fashion and Beauty
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• v.1 no.1 s.1
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• pp.105-118
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• 2003

The purpose of this study was to analyze entertainer Byeon Jeong-su's hair styles and thereby, apply the results to models. For the applications, models' hair styles were bisected into two sections, and thereby, the edges of the outsides were cut into solid points, and thereupon, into diverse bases by using vertical section, Perpendicular direction and square angles. On the other hand, the insides were cut in the same way of the outside bases by using radial section, varied combing and $45{\sim}90$ degree head angles. In addition, tops and sides were arranged in their corners, while a graduation technique was used to express a natural difference of levels. The fringes were cut by using free-hand and slicing techniques. furthermore, the quantity and mass of the hairs were treated with such techniques as thinning, swing, effect, rolling, slide and slicing, while a bridge product was used for coloring together with a highlight technique. The hair styles were rendered for straight and wave by using an magic iron machine. It was confirmed through this study that the same cutting techniques would result in different images depending on individuals' physical shapes, facial shapes, head skeletons and types of hairs. Thus, it is required of the hair designers to suggest their own custom hair designs adequate to individuals' images through continued image-wise hair design practices.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.294-299
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• 2001

Objectives : CT-guided stereotactic evacuation for spontaneous intracerebral hemorrhage can minimize the brain damage and can be performed safely and simply under local anesthesia. But that procedure is time consuming and has a risk of rebleeding because of the stress during head pin fixation. So authors describe easy and precise guidelines for FHA of putaminal hemorrhage without stereotactic instrument. Methods and Materials : We analyzed the data of 298 patients who underwent CT-guided stereotactic aspiration of putaminal hematoma in our hospital between January 1990 and December 2000. We divided the patients into three groups according to the location of hematoma : anterior portion, middle portion and posterior portion of putamen. Total number of catheters inserted into the hematoma were 345 and there were with regard to the direction and depth of catheters. Results : Proposed guidelines of catheter insertion to putaminal hemorrhage in our institution. 1) hematoma at the anterior portion of putamen ; Direction of catheter was the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between external auditory meatus(EOM) and 1cm posterior to EOM. Depth of catheter was 6-6.5cm. 2) hematoma at the middle portion of putamen ; Direction of catheter was the midpupillary line of the the eye and the point intersecting a line drawn from the burr hole to a point between 1cm and 2cm posterior to EOM. Depth of catheter was 6.5-7cm. 3) hematoma at the posterior portion of putamen ; Direction of catheter was 15 degree laterally from the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between 2cm and 3cm posterior to EOM. Depth of catheter was 7-7.5cm. We have performed FHA of putaminal hemorrhage in 48 cases according to this guideline. All catheter were inserted exactly at the center of hematoma and average operation time was about 30 minutes. Conclusion : Our proposed guidelines for putaminal hemorrhage are considered to be safe and simple method with similar accuracy and rapid decompression compared with traditional stereotactic method. Main advantages of this technique were unnecessity of stereotactic frame application and less time requirement for hematoma removal.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1392-1399
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• 2001

The flow fields inside a molten Zn pot of continuous hot-chip galvanizing process were investigated experimentally. With varying several parameters including the strip speed Vs, flow rate Q of induction heater. scrapper location and baffle configuration, instantaneous velocity fields were measured using a PIV velocity field measurement technique. Inside the strip region, counter-clockwise rotating flow is dominant. The general flow pattern inside the strip region is nearly not influenced by the strip speed Vs, flow rate Q and the scrapper location. In the exit region, the flow separated from the moving strip due to the existence of a stabilizing roll ascends to the free surface, for the cases of no scrapper and scrapper detached form the roll. On the other hand, the ascending flow to the free surface is decreased, as the flow rate Q of induction heater increases. By installing a baffle around the uprising strip, the flow moving up to the stabilizing roll decreases. In addition, B-type baffle is better than A-type baffle in reducing speed of flow around the stabilizing rolls. However, the flow ascended to the free surface is largely influenced by changing the flow rate Q, and the scrapper location, irrespective of the baffle type.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1546-1551
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• 2004

The laser Doppler technique is well-established as a velocity measurement technique of high precision for flow velocity. Recently, the laser Doppler technique has also been used to measure acceleration of fluid particles. Acceleration is interesting from a fluid mechanics point of view, since the Navier Stokes equations, specifically the left-hand-side, are formulated in terms of fluid acceleration. Further, there are several avenues to estimating the dissipation rate using the acceleration. However such measurements place additional demands on the design of the optical system; in particular fringe non-uniformity must be held below about 0.0001 to avoid systematic errors. Relations expressing fringe divergence as a function of the optical parameters of the system have been given in the literature; however, direct use of these formulae to minimize fringe divergence lead either to very large measurement volumes or to extremely high intersection angles. This dilemma can be resolved by using an off-axis receiving arrangement, in which the measurement volume is truncated by a pinhole in front of the detection plane. In the present study an optical design study is performed for optimizing laser Doppler systems for fluid acceleration measurements. This is followed by laboratory validation using a round free jet and a stagnation flow, two flows in which either fluid acceleration has been previously measured or in which the acceleration is known analytically. A 90 degree off-axis receiving angle is used with a pinhole or a slit.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.71-86
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• 2021

Purpose - This study examines the awareness regarding the symptoms of COVID-19 exposures and safety distances strategies whether they were useful to resile the businesses a mid of the pandemic. Besides exploring the awareness and safety distances, the effectiveness of offering free use of protective equipment (mask, hand sanitizer, frequent hand washing, etc.) to the customers for visiting the business centers was also examined. Design/methodology/approach - This study collected 264 survey data in Bangladesh which is one of the most densely populated country and very vulnerable for COVID-19 due to its socio-economic condition. The multiple regression analysis is used to analyze the data. Findings - The findings of the study indicate that the awareness about the symptoms of virus exposures (cough, fever, diarrhea, and weakness) has significant affirmative effects to enhance the public movement for business purposes with the lower possibility to be affected by the virus. The study also indicates that safety distances and protective equipment can mediate the significant positive relationship between the awareness of the disease and the businesses' resilient capacity. Research implications or Originality - COVID-19, as an apprehensive health issue in the current world, has sharpened the uncertainty of the businesses. One essential technique as lockdown, has been followed by almost every country to protect the transmission of the virus even though the scholars criticized it due to the substantial adverse effects on the country's economy. Under this circumstances, this study provides implications to the relevant businesses by assessing the nexus between the safety distances and the proper uses of protective equipment with the business resilient.

• Smart Structures and Systems
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• v.31 no.3
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• pp.229-245
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• 2023

The absence of excitation measurements may pose a big challenge in the application of structural damage identification owing to the fact that substantial effort is needed to reconstruct or identify unknown input force. To address this issue, in this paper, an iterative strategy, a synergy of Tikhonov regularization method for force identification and modified Jaya algorithm (M-Jaya) for stiffness parameter identification, is developed for damage identification with partial output-only responses. On the one hand, the probabilistic clustering learning technique and nonlinear updating equation are introduced to improve the performance of standard Jaya algorithm. On the other hand, to deal with the difficulty of selection the appropriate regularization parameters in traditional Tikhonov regularization, an improved L-curve method based on B-spline interpolation function is presented. The applicability and effectiveness of the iterative strategy for simultaneous identification of structural damages and unknown input excitation is validated by numerical simulation on a 21-bar truss structure subjected to ambient excitation under noise free and contaminated measurements cases, as well as a series of experimental tests on a five-floor steel frame structure excited by sinusoidal force. The results from these numerical and experimental studies demonstrate that the proposed identification strategy can accurately and effectively identify damage locations and extents without the requirement of force measurements. The proposed M-Jaya algorithm provides more satisfactory performance than genetic algorithm, Gaussian bare-bones artificial bee colony and Jaya algorithm.