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

• Journal of Broadcast Engineering
• /
• v.22 no.1
• /
• pp.42-50
• /
• 2017

A Bit-depth expansion is a method to increase the number of bit. It is getting important as the needs of HDR (High Dynamic Range) display or resolution of display have been increased because the level of luminance or expressiveness of color is proportional to the number of bit in the display. In this paper, we present effective bit-depth expansion algorithm for conventional standard 8 bit-depth content to display in high bit-depth device (10 bits). Proposed method shows better result comparing with recently developed methods in quantitative (PSNR) with low complexity. The proposed method shows 1db higher in PSNR measurement with 40 times faster in computational time.

• The Korean Journal of Emergency Medical Services
• /
• v.24 no.2
• /
• pp.39-50
• /
• 2020

Purpose: This study aimed to compare the effect of chest compression and the resulting ventilation volume in walking cardiopulmonary resuscitation (CPR), straddling CPR, and mechanical CPR while moving manikins to main stretchers. Methods: We compared the chest compressions in terms of compression depth, number of incomplete releases, complete release depth, compression rate, duration between peak time of previous compression and peak time of current compression, and respiration. We analyzed the compression comparatively with the ventilation volume in three different types of CPR. Results: The chest compression depth was significantly improved during straddling CPR as compared to walking CPR, during which women were unable to achieve sufficient chest compression depth. A constant chest compression depth was maintained during mechanical CPR. Conclusion: High-quality chest compressions were difficult to achieve in moving spaces. Further, walking CPR may be helpful in men, but straddling or applying automatic chest compressions in women would result in more effective CPR. Our findings demonstrate the limitations and trends in administering CPR in men and women, which may be useful in devising better education and training methods in the future.

• Journal of Information Processing Systems
• /
• v.19 no.4
• /
• pp.483-497
• /
• 2023

Depth estimation is one of the most complicated and difficult problems to deal with in the light field. In this paper, a compound attention convolutional neural network (CAttNet) is proposed to extract depth maps from light field images. To make more effective use of the sub-aperture images (SAIs) of light field and reduce the redundancy in SAIs, we use a compound attention mechanism to weigh the channel and space of the feature map after extracting the primary features, so it can more efficiently select the required view and the important area within the view. We modified various layers of feature extraction to make it more efficient and useful to extract features without adding parameters. By exploring the characteristics of light field, we increased the network depth and optimized the network structure to reduce the adverse impact of this change. CAttNet can efficiently utilize different SAIs correlations and features to generate a high-quality light field depth map. The experimental results show that CAttNet has advantages in both accuracy and time.

• Journal of Ocean Engineering and Technology
• /
• v.19 no.6 s.67
• /
• pp.16-21
• /
• 2005

In the design of super tankers or LNG carriers, which transport a large amount of liquid in the cargo tanks, the structural d11mage due to liquid sloshing is an important problem. The impact pressure from sloshing is most violent when the liquid motion of a partially filled tank is in resonance with the motion of a ship. In this study, the sloshing natural periods of a baffled tank, often installed to reduce liquid motion, is analyzed. A variational method is adopted to estimate the sloshing natural periods for a prismatic cargo tank with baffles of arbitrary filling depth of liquid; the results are compared with Lloyd's Register regulations on sloshing periods. In this study, using an effective liquid-fill-depth concept, sloshing periods for a baffled tank can be expressed by the same form as rectangular prismatic tanks without baffles. In contrast to Lloyd's Register regulations, which can be applicable only to cargo tanks with constant baffle size and distribution, the present results can be applicable to cases of variable baffle size and distribution.

• Journal of Animal Environmental Science
• /
• v.1 no.1
• /
• pp.1-8
• /
• 1995

Litters such as sawdust and rice hulls are used to manage the waste excrements of Hanwoo(Korean Native Cattle). This experiment was conducted to investigate the adequate depth of bedding materials, and the effective substitutive rate of rice hulls and the recycled-dried sawdust mixed with cattle waste for sawdust from 1993 to 1994. The results were as follows; 1. The most adequate bedding depth of sawdust was 4cm and it was able to be utilized for 38 days. The cost of required sawdust was lower in order of 5, 15, 20 and 10cm in depth of bedding sawdust. 2. Rice hulls was able to be fully substituted for sawdust, but 50% substitution the most effective. 3. Recycled-dried sawdust mixed with cattle waste could be substituted less than 25% for sawdust.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.17 no.4
• /
• pp.451-458
• /
• 2004

The study was focused on the development of computational scheme in three dimensional configurations by applying effective heat capacity model to the numerical procedure in order to predict the temperature profiles of a buried pipeline and the frozen penetration depth(FPD) of a freezing soil medium. To realize this, the investigator conducted the unsteady state heat transfer analysis, using the commercial code ABAQUS, for the freezing granite soil medium including a pipeline in a closed system. The proposed model took into consideration the phase change effect of in situ pore water in the frozen fringe. The comparison of results obtained by the proposed model and the actual performances was valuable in establishing a level of confidence in the application of introduced theory.

• Nuclear Engineering and Technology
• /
• v.35 no.2
• /
• pp.144-153
• /
• 2003

The object of this paper is the probabilistic failure analysis on the cladding performance of WPF(Whole Pin Furnace) test fuel pins under transient conditions, and analysis of the KALIMER fuel pin using the preceding analysis. The cumulative damage estimation and Weibull probability estimation of WPF test are performed. The probabilistic method was adapted for these analyses to determine the effective thickness thinning due to eutectic penetration depth. In the results, it is difficult to assume that a brittle layer depth made by eutectic reaction is all of the thickness reduction due to cladding thinning. About 93% cladding thinning of the eutectic penetration depth is favorable as an effective thickness of cladding. And the unreliability of the KALIMER driver fuel pin under the same WPF test condition is lower than that of the WPF pin because of the higher plenum-fuel volume ratio and lower cladding inner radius vs. thickness ratio. KALIMER fuel pin developed from conceptual design has a more stable transient performance for a failure mechanism due to fission gas buildup than the WPF pin.

• Journal of the Korea Concrete Institute
• /
• v.28 no.3
• /
• pp.257-265
• /
• 2016

The failure behavior of reinforced concrete beams is governed by the mechanical relationships between the shear span-to-effective depth ratio, flexural reinforcement ratio, load and support conditions, and material properties. In this study, two simple indeterminate strut-tie models which can reflect all characteristics of the failure behavior of reinforced concrete beams were proposed. The proposed models are effective for the beams with shear span-to-effective depth ratio of less than 3. For each model, a load distribution ratio, defined as the fraction of load transferred by a truss mechanism, is also proposed to help structural designers perform the rational design of the beams by using the strut-tie model approaches of current design codes. In the determination of the load distribution ratios, the effect of the primary design variables including shear span-to-effective depth ratio, flexural reinforcement ratio, and compressive strength of concrete was reflected through numerous material nonlinear analysis of the proposed indeterminate strut-tie models. In the companion paper, the validity of the proposed models and load distribution ratios was examined by applying them to the evaluation of the failure strength of 335 reinforced concrete beams tested to failure by others.

• The Korean Journal of Pain
• /
• v.24 no.4
• /
• pp.216-220
• /
• 2011

Background: Transforaminal epidural steroid injection is one of the effective treatments in managing radicular pain. There have been some prospective studies on the depth to the epidural space with the transforaminal approach. However, there have been no studies about the depth in Asians, especially Koreans. This study was carried out in order to evaluate the depth to the epidural space and the oblique angle and factors that influence the depth to the epidural space during lumbar transforaminal epidural injection. Methods: A total of 248 patients undergoing fluoroscopically guided transforaminal epidural steroid injections were evaluated. At the L3-4, L4-5, L5-S1, and S1 levels, we measured the oblique angle and depth to the epidural space. Results: Needle depth was positively associated with body mass index (correlation coefficient 0.52, P = 0.004). The median depths (in centimeters) to the epidural space were 6.13 cm, 6.42 cm, and 7.13 cm for 50-60 kg, 60-70 kg, and 70-80 kg groups, respectively, at L5-S1. Age and height were not significantly associated with the needle depth. Conclusions: There is a positive association between the BMI (and weight) and transforaminal epidural depth but not with age, sex, and height.