• Proceedings of the KWS Conference
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• 1997.10a
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• pp.77-80
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• 1997

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, predicting methods of fatigue life of spot welded joint have been studied fatigue life of conch-peel spot welded joint was influenced by tail effect. Fatigue life was estimated by stress index parameter considering multiaxial stresses and tail effect. Fatigue tests were conducted with the coach-peel specimens using SPCC.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.177-184
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• 2013

This study analyzed the hydraulic characteristics of a venturi flume with a circular cone using a 3-D numerical model which uses RANS(Reynolds-Averaged Navier-Stokes Equation) as the governing equation. The venturi flume with the circular cone efficiently measures the discharge in the low-flow to high-flow range and offers the advantage of accurate discharge measurements in the case of a low flow. With no influence of the tail-water depth, the stage-discharge relationship and the flow behaviors were analyzed to verify the numerical simulation results. Additionally, this study reviewed the effect of the tail-water depth on the flow. The stage-discharge relationship resulting from a numerical simulation in the absence of an effect by the tail-water depth showed a maximum margin of error of 4 % in comparison to the result of a hydraulic experiment. The simulation results reproduced the overall flow behaviors observed in the hydraulic experiment well. The flow starts to become influenced by the tail-water depth when the ratio of the tail-water depth to the total head exceeds approximately 0.7. As the ratio increases, the effect on the flow tends to grow dramatically. As shown in this study, a numerical simulation is effective for identifying the stage-discharge relationship of a venturi flume with various types of venturi bodies, including a venturi flume with a circular cone.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.99-111
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• 2024

Purpose - This study aims to quantify the long tail effect in the digital economy. It also investigates the role of digital platform before and after the COVID-19 pandemic. Design/methodology/approach - We take advantage of a granular data set from one of the biggest digital platforms in Korea. Rather than computing the absolute number of products sold or the Gini coefficient, we estimate the slope of the log-linear relationship of the non-parametric sales distribution. Findings - We find that the use of online food order and delivery services is positively associated with individual restaurant's sales growth. We also document that the long tail effect is increasing over time. Long tail effects are clustered in the cross-section where average revenue per order is high or the restaurant belongs to the top 50% of the sales distribution. Research implications or Originality - The findings may indicate that digital platforms are contributing to the development of the digital economy in Korea. Also, we confirm that digital platforms make it possible for small and sole proprietors to go through the difficulties induced by the COVID-19 pandemic.

• Journal of Korean Library and Information Science Society
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• v.38 no.3
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• pp.73-90
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• 2007

The Pareto principle, also known as the 80/20 rule, describes this common pattern of sales concentration. But long tail principle, that expose the power of majority which had been put aside for a long time, rise as a new business strategy in web 2.0 era. In digital and online environment, as created the conditions that satisfy the need of diversity, long-tail effect has been relevant to all social cultures. This paper consider the long-tail effect from a library service point of view and develop library's long-tail strategies. For the more, suggest practical plan about library long-tail based on library 2.0.

• Journal of Nutrition and Health
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• v.37 no.9
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• pp.794-800
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• 2004

Deer Antler has been known for its traditional oriental medicinal properties and has been widely used to promote growth, boost immune function, treat blood loss and chronic joint pain. Recent study showed imported (New Zealand) Deer Antler was beneficial in reducing the side effects of cancer treatments. However, there was no intervention study conducted on the effect of Korean Deer Antler on reducing the oxidative stress to patients with diabetes. One of the sensitive ways to measure endogenous oxidative stress is by measuring cellular DNA damage using single cell gel electrophoresis (COMET assay). This study was conducted to investigate the possible beneficial effect of commercial Deer Antler drink (provided by Chung-yang Deer Farm) on lymphocyte DNA damage and blood glucose of diabetic patients. Ten patients (4 men, 6 women) participated in the study and consumed 2 pouches of Deer Antler drink every day for 20 days. Blood was collected on the morning before and after the intervention for lymphocyte isolation and blood glucose analysis. Both systolic and diastolic blood pressure showed a tendency to decrease but did not reach statistical significance after the trial. Blood glucose level was not affected by the supplementation. After the intervention, over 50% reduction were noted in the cellular DNA damage, expressed as tail length (TL) and tail moment (TM: tail length ${\times}$ percent tail DNA) . Although we did not obtain beneficial effect on lowering blood glucose levels in the patients, this results suggest that Deer Antler may initially act in protecting endogenous DNA damage in short-term experiment.

• The Journal of Korean Physical Therapy
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• v.9 no.1
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• pp.89-96
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• 1997

The purpose of this study was to determine the effect of Ga-Al-As (Gallium-Aluminum-Arsenid) laser radiation on the tail-flick latency in rat. Thirty Sprague-Dawley male and female rats Were divided into five groups : that is control, laser 15sec radiation, laser 30sec radiation, laser 60sec radiation, and Tramadol Hcl injection groups. The continuous Ga-Al-As laser with, wave length 780-830nm and diameter of probe in the 3mm, averse output of 100mw radiation was applied to the meridian point(Gv 1 : Governing vessel) of the rats. Tail-flick latency were measured with hot plate at $55^{\circ}C$ : before treatment and immediately, 30 minutes, 1 hour, 2 hours, 24 hours, 24 hours and 48 hours after treatment. The result were as follows ; 1. The tail-flick latency according to time varition, control group was not significance. 2. The tail-flick latency according to time varition, laser 15 sec irradiate rats in post-treared was significance(P<0.05). 3. The tail-flick latency according to time varition, laser 30 sec irradiate rats group was not significance. 4. The tail-flick latency according to time varition, laser 60 sec irradiate rats in post 30 minute was significance(P<0.05). 5. The tail-flick latency according to time varition, Tramadol Hcl injection rats in post-treated (P<0.05), post 30 minute(P<0.05), post 60 minute (P<0.01) and 2 hour(P<0.05) was significance. This study suggest that Ga-Al-As (Gallium-Aluminum-Arsenid) laser applied to meridian point of the rat with 15 sec, 30 sec, and 60 set radiation could induc no analgesic effect, but Tramadol Hcl injection rat is good analgesic effect.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.149-156
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• 2007

A three-dimensional inviscid flow solver has been developed based on unstructured meshes for the simulation of steady and unsteady flowfields around a generic fighter aircraft and for the investigation of the aerodynamic interference between the external stores and the tail surfaces. The flow solver is based on a vertex-centered finite-volume method and an implicit point Gauss-Seidel relaxation scheme. To validate the flow solver, calculations were made for a steady flow and the computed results were compared with experimental data. An unsteady time-accurate computation of the generic fighter aircraft with external stores at transonic flight conditions showed that the external stores cause undesirable vibration on the horizontal tail surface due to the mutual interference between their wake and the horizontal tail surface. It was shown that downward deflection of the trailing edge flap significantly reduces the undesirable interference effect.

• Structural Engineering and Mechanics
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• v.13 no.3
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• pp.345-353
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• 2002

Three noded plate and shell finite element and 3D beam element in conjunction with Lanczos method are used for studying the effect of boat tail angle on the free vibration characteristics of a typical payload fairing for three different cylinder diameters with height to diameter ratio 1.5. Configurations without boat tail structural member are also studied. One half of the one side fairing structure is considered for the analysis and symmetric boundary conditions are used.

• The Journal of Korean Physical Therapy
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• v.8 no.1
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• pp.15-20
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• 1996

The purpose of this study were to 1) determine the analgesic effect of 632.8 nm of helium-neon (He-Ne) laser stimulation on acupuncture point in rat and 2) determine the reversal of analgesic effect by naloxone injection. Eighteen Sprague-Dawley rats were devided into three groups : control (n=6) : laser (n=6), laser stimulation at $3.58\;J/cm^2$ ; and naloxone (n=6), 1 mg/kg of naloxone chloride inject into peritoneum before laser stimulation at $3.63J/cm^2$. Tail-flick latency were measured pretreat and posttreat with hot plate $(55^{\circ}C)$. Data were analyzed using one-way ANOVA and paired t-teat for tail-flick latency. No significant change was noted in the tail-flick latency in either control or naloxone groups. But significant increased in tail-flick latency in taller group. The results suggest that He-Ne laser induced analgesic effect, and endogenous opioids may be involved in He-Ne laser induced analgesia.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.139-149
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• 1989

Although tail flick reflex (TFR) in rats has been used as a classic model of the nociceptive test to evaluate the action of analgesics, there have been few studies on the origin of the latent period of TFR. Present study was performed to elucidate the mechanism of increase in latency of TFR by morphine in anesthetized rats. Tail skin and dorsolateral tail nerve were stimulated electrically and EMG activities were recorded from abductor caudae dorsalis muscle participating in tail flick reflex. In the case of noxious radiant heat stimulation to tail, the tail flick tension was recorded before and after administration of morphine. Then changes in latency and conduction velocity of peripheral nerve were evaluated. The results obtained were as follows: 1) The latencies of TFR evoked by the electrical stimulation of tail skin and dorsolateral tail nerve were all within 40 ms and were elongated by several milliseconds from control after the administration of morphine. Peripheral conduction velocities of tail flick afferent nerve were within the range of 10-25 m/s. 2) The conduction velocity of peripheral nerve was significantly reduced after morphine administration, therefore the afferent time (utilization time+conduction time to spinal cord) was significantly increased. But the time for central delay and efferent time was not affected by morphine. 3) The conduction velocity under room temperature $(20-25^{\circ}C)$ was significantly reduced after morphine while that under vasodilation state $(40{\sim}42^{\circ}C)$ increased, 30 min and 45 min after morphine. The conduction velocity under vasodilation state without treatment of morphine increased continuously 4) The latency in tension response of TFR evoked by electrical stimulation was elongated by several milliseconds from control while the latency evoked by noxious radiant heat was elongated by several seconds compared with that of control. From the above results, it could be concluded that: 1) the increased latency of TFR evoked by electrical stimulation of the tail after morphine administration was due to the reducton in conduction velocity of peripheral nerve, which was the secondry effect of morphine on the peripheral vasomotion and 2) increased latency of TFR evoked by noxious radiant heat was also due to the same effect of morphine and the increase in cutaneous insulation to the noxious heat.