• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.4
• /
• pp.377-386
• /
• 2021

In dense cities, which are covered by many impermeable areas, rainwater flows quickly along the roads and collects in certain areas. The surface runoff that fails to get intercepted by the roadside rain gutters results in a wider flow of water along the sides, which in turn increases the amount of water on the road and causes traffic congestion as well as accidents due to slippage. Based on these issues, this study was carried out in order to propose an intercepted flow calculation formula. To this end, the maximum longitudinal slopes of arterial roads and expressways were reflected to depict a road condition of 2~10 %, while a general traverse slope of 2 % was selected for the traverse slope on the side. As for the road lane condition, two, three, and four lanes were chosen for the area from the centerline to the sidewalk. As for the experimental flow rate, the rainwater runoffs at the actual design frequency of 5, 10, 20, and 30 years for road conditions were converted into experimental flow rates, and as a result, flow rates ranging from 1.36 l/s to 3.96 l/s were divided into ten flow rates for a hydraulic experiment. Also, an equation taking into consideration the inflow velocity and flow width along the roadsides was proposed. The results of the experiment showed an increase in flow width and a decrease in interception rate. Also, the inflow velocity at a traverse slope of 2 % was measured, while increasing the longitudinal slope. Accordingly, an equation for calculating the flow intercepted by rain gutters at a flow width reflecting the longitudinal slope of the road and rainwater runoff, according to the design frequency, was derived by performing a regression analysis using IBM SPSS Statistics 24. It is deemed that the equation derived in this study will be useful in designing rain gutters for roads.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.3
• /
• pp.108-127
• /
• 2014

Gangwha was a capital city of Goryeo, in spite of short-term occupation, where various national facilities such as palace stood in a row. Nevertheless, its historic importance has been undervalued owing to undiscovered palace. According to ${\ll}Goryeosa{\gg}$, palace in Gangwha was built in imitation of that of Gaegyeong. If it is true, the site of the old palace in Gaeseong as an original could give significant information for that of Gangwha. The distinct feature of Gaegyeong is that the palace was located in the west area of the centerline from north to south and pond lay in the east side. There is a mountain in the center of capital and two rivers runs along side the mountain. Gunggol at Gwancheong-ri is a best place where structural peculiarities of Gaegyeong can be applicable to Gangwha. There is an area of celadon distribution and is some topographic similarities such as central mountain, two rivers are quite similar. It is assumable that excavation result of no. 405 Gwancheongri reflects the function of east pond and thoroughfare responds to main street from north to south of Gaegyeong. After all the analysis from archaeological information, old maps, cadastral maps, topographic similarities and so on, Gunggol at Gwancheong-ri within an arc shape road is a most suitable place as palace in Gangwha.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.6D
• /
• pp.931-936
• /
• 2008

Surveying by using terrestrial LiDAR(Light Detection And Ranging) is more rapid than by using total station which enables tunnel section profile surveying to be done in suitable time and minimize centerline error, occurrence of overcut and undercut. Therefore, utilization of terrestrial LiDAR has increased more and more in section profile survey and measurement field Moreover, studies of terrestrial LiDAR for accurate and efficient utilization is now ongoing vigorously. Average end area formula, which was generally used to calculate overcut and undercut, was compared with existing methods such as total station survey and photogrammetry. However, there are no criteria of spacing distance for calculating overcut and undercut through terrestrial LiDAR surveying which can acquire 3D information of whole tunnel. This research performed reverse engineering to decide optimal spacing distance when surveying tunnel section profile by comparing whole tunnel volume and tunnel volume in difference spacing distance. This result was utilized to produce CAD drawing for the test tunnel site where there is no design drawings. In addition to this, efficiency of LiDAR and accuracy of CAD drawing was compared with targetless total station surveying of tunnel section profile. Finally, error analysis of target coordinate's accuracy and incidence angle was done in order to verify the accuracy of terrestrial LiDAR technology.

• Korean Journal of Radiology
• /
• v.22 no.5
• /
• pp.688-698
• /
• 2021

Objective: To compare the lumen parameters measured by the location-adaptive threshold method (LATM), in which the inter- and intra-scan attenuation variabilities of coronary computed tomographic angiography (CCTA) were corrected, and the scan-adaptive threshold method (SATM), in which only the inter-scan variability was corrected, with the reference standard measurement by intravascular ultrasonography (IVUS). Materials and Methods: The Hounsfield unit (HU) values of whole voxels and the centerline in each of the cross-sections of the 22 target coronary artery segments were obtained from 15 patients between March 2009 and June 2010, in addition to the corresponding voxel size. Lumen volume was calculated mathematically as the voxel volume multiplied by the number of voxels with HU within a given range, defined as the lumen for each method, and compared with the IVUS-derived reference standard. Subgroup analysis of the lumen area was performed to investigate the effect of lumen size on the studied methods. Bland-Altman plots were used to evaluate the agreement between the measurements. Results: Lumen volumes measured by SATM was significantly smaller than that measured by IVUS (mean difference, 14.6 mm³; 95% confidence interval [CI], 4.9-24.3 mm³); the lumen volumes measured by LATM and IVUS were not significantly different (mean difference, -0.7 mm³; 95% CI, -9.1-7.7 mm³). The lumen area measured by SATM was significantly smaller than that measured by LATM in the smaller lumen area group (mean of difference, 1.07 mm²; 95% CI, 0.89-1.25 mm²) but not in the larger lumen area group (mean of difference, -0.07 mm²; 95% CI, -0.22-0.08 mm²). In the smaller lumen group, the mean difference was lower in the Bland-Altman plot of IVUS and LATM (0.46 mm²; 95% CI, 0.27-0.65 mm²) than in that of IVUS and SATM (1.53 mm²; 95% CI, 1.27-1.79 mm²). Conclusion: SATM underestimated the lumen parameters for computed lumen segmentation in CCTA, and this may be overcome by using LATM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.37 no.4
• /
• pp.394-399
• /
• 2024

An irradiator is developed using two UVA wavelength ranges of SMD LEDs as a curing light source. This module has dimensions of 545×111×300 mm³ and is equipped with a TIR bar-shaped lens made of PDMS silicone resin. The developed irradiator offers high uniformity, with 89% in the centerline of the horizontal axis direction, for two different wavelength ranges of 365 nm and 385 nm. The radiation intensity from the light source module shows highly directional characteristics, and the irradiator provides a maximum irradiance of 1,634 mW/cm² at a working distance of 50 mm. During the initial 5 minutes of operation, the irradiance experiences a rapid decrease. However, this issue is addressed by optimizing the LED's current reduction characteristics and managing the Transistor's temperature rise in the constant current circuit. After continuous operation for approximately 60 minutes. The highest temperature, near the central part of the irradiating surface, reaches 69.7℃, while the lowest temperature, near the edges, is 41.1℃.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.355-362
• /
• 2014

Purpose : When head&neck cancer radiation therapy, thermoplastic mask is applied for patients with fixed. The purpose of this study is to evaluate usefulness of thermoplastic mask for SRS in tomotherapy by conparison with the conventional mask. Materials and Methods : Typical mask(conventional mask, C-mask) and mask for SRS are used to fix body phantom(rando phantom) on the same iso centerline, then simulation is performed. Tomotherapy plan for orbit and salivary glands is made by treatment planning system(TPS). A thick portion and a thin portion located near the treatment target relative to the mask S-mask are defined as region of interest for surface dose dosimetry. Surface dose variation depending on the type of mask was analyzed by measuring the TPS and EBT film. Results : Surface dose variation due to the type of mask from the TPS is showed in orbit and salivary glands 0.65~2.53 Gy, 0.85~1.84 Gy, respectively. In case of EBT film, -0.2~3.46 Gy, 1.04~3.02 Gy. When applied to the S-mask, in TPS and Gafchromic EBT3 film, substrantially 4.26%, 5.82% showed maximum changing trend, respectively. Conclusion : To apply S-mask for tomotherapy, surface dose is changed, but the amount is insignificant and be useful when treatment target is close critical organs because decrease inter and intra fractional variation.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.7
• /
• pp.2386-2396
• /
• 1996

A numerical simulation has been performed for isothermal and reacting flows in an exisymmetric, bluff-body research combustor. The present formulation is based on the density-weighted averaged Navier-Stokes equations together with a k-epsilon. turbulence model and a modified eddy-breakup combustion model. The PISO algorithm is employed for solution of thel Navier-Stokes system. Comparison between measurements and predictions are made for a centerline axial velocities, location of stagnation points, strength of recirculation zone, and temperature profile. Even though the numerical simulation gives acceptable agreement with experimental data in many respects, the present model is defictient in predicting the recoveryt rate of a central near-wake region, the non-isotropic turbulence effects, and variation of turbulent Schmidt number. Several possible explanations for these discrepancies have been discussed.

• The Korean Journal of Air & Space Law and Policy
• /
• v.23 no.2
• /
• pp.115-136
• /
• 2008

The development of the aviation technology is beyond the people's imagination. For example, with some exaggeration, If the autopilot engage upon take off, You will realize that you are on the centerline of the foggy JFK runway 13R after 15 hours with only once or twice of intervention. But the more aviation technology develops, the more responsible the pilot will be who has the final authority of the aviation safety. In the JAL 706 accident caused by unidentified reason, the pilot increased pitch abruptly and overrode the control from the autopilot. The result of this process made the death of a flight attendant and some injuries of a few passengers. The district court found the pilot not guilty at the first trial on the ground that the control override was not connected to the possibility of foresight and avoidance of the human death. The pilot was proved to be innocent through the analysis of the DFDR and ADAS that the override did not precede the unidentified pitch up motion. The judicial precedent related to aviation accidents in Korea requires pilots' absolute and extended care compared to the ordinarily prudent or reasonably careful behaviors in the vehicle and medical accidents. Although there is some controversy about the standard care, the care required in the actual operation of high tech aircraft by a pilot should include objective and standard care and be judged by analysis of the scientific data. Although the pilot maintained the unusual hi speed that doesn't have safety margin and descended under turbulence in case of the JAL 706 accident, the court negatived its relation to the cause of pitch up. Also, the override of the control after initial pitch up might have caused the possibility of the death and injury, but the court denied it. Because of this complex cause of the aviation accidents, it is important for a court to figure out the core reason of the event and casual relationship with the pilot Now, It is required that the judgement of negligence in the aviation accidents should include an objective care with scientific data from simulated circumstances(or a simulator) as the Japanese court not from the theory of vehicle's negligence.