• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.5
• /
• pp.433-441
• /
• 2006

With a development of electrical technology in recent, it is possible to measure distance without direct contact to object using laser which launched at instrument and reflect from object. Furthermore, the advent of non prism total station brought the increment of application in many fields including not only road, airport, and harbors but also measurement and monitoring of structural displacement in construction fields. In this study, therefore, to evaluate accuracy of non prism total station, accuracy was analyzed by measuring certain distance which classified by both certain materials and angle of reflection. By this method, the derived values were applied to topographical survey for the efficient applicability. According to a study, result value of non prism total station was satisfBctory regardless of material when the angle of reflection was 90 degrees. RMSE increased when the angle of reflection are gradually increased to acute angle. In result of regression analysis using certain distance which classified by both materials and angles of reflection, there is relationship between distance and angle of reflection, but material has no relevance to the result value. When carrying out general topographical survey, proper application of non prism total station will go far conducting safe and prompt survey at the dangerous site such a road which have lots of traffic flow and rock joint which have high angles of inclination.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.1
• /
• pp.61-71
• /
• 2009

Anchorage control is important in orthodontic treatment. Recently miniscrew is widly used as maximum anchorage in orthodontic treatment, and then it is important to install miniscrew safely without damaging adjacent anatomic structure. In a view of Miniscrew's stability, maxilla is unfavorable than mandible, and moreover maxillary soft buccal bone has disadvantage on stability. so palatal area comes into notice for installation area. We measured distance between palatal roots and bone thickness at midpalatal area using 3D computed tomography, and have found following results. 1. On the comparison of distance between palatal roots, the distance between 2nd premolar and 1st molar was significantly longest and the distance between premolars was significantly shortest. 2. Going toward lateral area from midpalatal suture and posterior area from zero point, bone thickness significantly became shorter and shorter. And 5.0mm palatal sagittal plane has more significance decrease of bone thickness than 2.5mm palatal sagittal plane. According to these results, we can conclude that the palatal installation of miniscrew between 2nd premolar and 1st molar is safest. And it is more safe that comes closer to midpalatal suture and to anterior area in regard to incisive canal.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.133-139
• /
• 2018

Keeping a proper straight route length under the marine bridge is one of the important factors for the safe passage of ships. However, according to port and harbor design standards, there is only a constant guideline of 8 times the length of the marine bridge underpass. On this study, we used the ES model to determine the ratio of risk to the route width, traffic volume, the degree of curvature of the route, and the length of the straight route in order to derive the optimal straight route distance. As a result, the risk ratio decreased by 2.27% as the route distance increased from 3L to 10L when the degree of curvature of the route was $45^{\circ}$. The risk associated with curvature was found to be 4.83% when the bending degree was changed from $0^{\circ}$ to $45^{\circ}$ in the case of 3L length. In addition, it was confirmed that the risk ratio according to the degree of curvature of the route and the straight route was reduced by 1.45% at maximum under the condition that the width of the line was 400m and the number of the vessels generated per hour was 20. It was verified that a straight route distance more than a certain length is needed depending on the congestion degree and the degree of curvature of the route when constructing the marine bridge.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.2
• /
• pp.267-278
• /
• 2019

Variety of tunnel ahead prediction methods have been performed for safe tunnel construction during tunnel excavation. Pole-pole array among the electrical resistivity survey, which is one of the tunnel ahead prediction method, has been utilized to predict water-bearing sediments or weak zone located within 5 times of tunnel diameter. One of the most important processes is the estimation of virgin ground resistivity and it can be obtained from the following process: 1) calculation of contact area between the electrodes and the medium, and 2) assumption of the electrodes as equivalent spherical electrodes which have a same surface area with the electrodes. This assumption is valid in a small contact area and sufficient distance between the electrodes. Since the measured resistance, in general, varies with the electrode size, shape, and distance between the electrodes, it is necessary to evaluate the influence of these factors. In this study, theoretical equations were derived and experimental tests were conducted considering the electrode size, shape, and distance of cylindrical electrodes which is the most commonly utilized electrode shape. Through this theoretical and experimental study, it is known that one should be careful to use the assumption of the equivalent half-spherical electrode with large ratio between the penetrated depth and radius of the cylindrical electrode, as the error may get larger.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2020

If a dangerous situation arises in a place where out of reach from the human, UAVs can be used to determine the size and location of the situation to reduce the further damage. With this in mind, this paper sets the minimum value of the roll, pitch, and yaw using beta flight to detect the UAV's smooth hovering, integration, and derivative (PID) values to ensure that the UAV stays horizontal, minimizing errors for safe hovering, and the camera uses Open CV to install the Raspberry Pi program and then HSV (color, saturation, Brightness) using the color palette, the filter is black and white except for the red color, which is the closest to the fire we want, so that the UAV detects the image in the air in real time. Finally, it was confirmed that hovering was possible at a height of 0.5 to 5m, and red color recognition was possible at a distance of 5cm and at a distance of 5m.

• Journal of Digital Convergence
• /
• v.10 no.10
• /
• pp.295-300
• /
• 2012

Various forward collision warning algorithms have studied in order to protect a car accident. For this, in general, algorithms using an external device such as a camera and sensor generate a forward collision warning. However, if using the external device, it can occur errors due to device characteristics when there is rain or fog. Also, the prevention of a chain-reaction collision is insufficient because the system generates a warning in case of only vehicle having a forward collision danger. If it combines the vehicle safety communications, the method becomes a solution to protect a chain-reaction collision. So, In this paper, we proposes a improved forward collision warning algorithm using the wireless communication technique, driver's information, breaking distance, and velocity. And we compare and analyze our algorithm and previous algorithms.

• Journal of Korean Neurosurgical Society
• /
• v.47 no.5
• /
• pp.338-344
• /
• 2010

Objective : This study assessed the safety and efficacy of one level unilateral laminotomy bilateral decompression (ULBD) with the placement of a device for intervertebral assisted motion (DIAM) compared with one level ULBD only in elderly patients with degenerative lumbar spinal stenosis (DLSS). Methods : A non randomized prospective analysis was performed on 16 patients who underwent one level ULBD with DIAM (Group A) and 20 patients with one level ULBD only (Group B) between February 2007 and March 2008. Radiographic imaging, visual analog scale (VAS) and MacNab outcome scale were obtained before and after surgery at a mean interval of 21 months (range 17-27 months). Results : The disc height, interpedicular distance, slip distance and segmental lordotic angle were similar between two groups. In the group A, there was no significant difference between the pre- and post-operative imaging in terms of the sagittal balance and disc height. Both groups showed significant improvement in the clinical outcomes. In addition, there was significantly less low-back pain in the group A than in the group B at the last follow up, while the clinical improvement of the leg pain and MacNab outcome scale showed no significant difference in the two groups. There were no major complications or DIAM associated complications. Conclusion : ULBD with DIAM is a safe and efficacious treatment for selective elderly patients with DLSS, particularly for relieving low back pain comparing to ULBD. ULBD with DIAM did not alter the disc height or sagittal alignment at the mean 21 months follow-up interval.

• Korean Journal of Remote Sensing
• /
• v.36 no.5_4
• /
• pp.1255-1266
• /
• 2020

In this study, a complex simulation prototype was developed for rapid and accurate prediction of chemical dispersion range in order to reduce human casualties caused by chemical accidents. Complex simulation considered the leakage momentum during the near-field dispersion to take into account the leakage characteristics of the chemical. In the far-distance dispersion process, the wind distribution of the existing model, which was presented uniformly, was improved using weather and topographical information around the accident site, to realize a wind field similar to the actual one. Finally, the damage range was more precise than the existing model in line with the improved near- and far-distance dispersion process. Based on the results of damage range prediction of the complex simulation, it is expected that it will be highly utilized as a system to support policy decision-making such as evacuation and return of residents after a chemical accident.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.6
• /
• pp.499-503
• /
• 2015

Objective : The transradial catheterization (TRC) is becoming widespread, primarily for neurointerventions. Therefore, the evaluation of radial artery puncture in clinical practice and a better understanding of the anatomy are important to improve the safety of neuroendovascular surgery. Methods : Ten formalin-fixed adult Korean cadavers were dissected to expose radial artery (RA), brachial artery (BrA) and subclvian artery (ScA), bilaterally. Vessel lengths and diameters were meaured using a caliper and distance between the specific point of vessels and the anatomical landmarks including the radial styloid process, the medial epicondyle of the humerus, the sternoclavicular joint, and the vertebral artery orifice were also measured. Results : The average length between the radial (RAPS) and the BrA puncture sites (BrAPS) and between the vertebral artery orifice (VAO) and the BrA bifurcation (BrAB) did not differ between sides (p>0.05). The average length between the radial styloid process (RSP) and the RAPS was $13.41{\pm}2.19mm$, and the RSP was $26.85{\pm}2.47mm$ from the median nerve (MN). The mean length between the medial epicondyle (ME) and the BrAPS as $44.23{\pm}5.47mm$, whereas the distance between the ME and the MN was $42.23{\pm}4.77mm$. The average VAO-ScA angle was $70.94{\pm}6.12^{\circ}$, and the length between the ScA junction (SCJ) and the VAO was $60.30{\pm}8.48mm$. Conclusion : This study provides basic anatomical information about the radial artery and the brachial route and can help improving new techniques, selection of size and shape of catheters for TRC. This can help neurointerventionists who adopt a transradial neuroendovascular approach and offers comprehensive and safe care to their patients.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.04a
• /
• pp.203-209
• /
• 1999

In this study, the structural deflection analysis of robot manipulator for removing nuclear fuel rod from nuclear reactor vessel is performed by using general purpose finite element code (ANSYS). The structural deflection analysis results reported in this study is very required for the accurate design of robot system. The structural deflection analysis for the manipulator's structural status at which the gripper grasps and draws up the nuclear fuel rod is done, For this beginning structural status of robot manipulator's removing motion, the reaction forces at each joint have static maximum values as reported in the reference(6), and so these forces may cause the maximum deflection of robot structure. The structural deflection analysis is performed for selected four working cases of the proposed structural model and results on deformation, stress for the manipulator's solid body and the deflection at the end of robot manipulator's gripper are calculated. And further, the same analysis is performed for the slenderer manipulator with cross section reduced by one-fifth of each side length of proposed model. The analysis is performed not only for the nuclear fuel rod with weight load of 300kg but also for nuclear fuel rods with weight loads of 100kg, 200kg, 400kg and 500kg. The static structural deflection analysis results show that the deflection value increases as the load increases and the largest value (corresponding to the weight load of 500kg in case 1) is much smaller than the gap distance between nuclear fuel rods. but the largest value for the slenderer manipulator is almost as large as the gap distance, Hence, conclusively, the proposed manipulator's structural model is acceptably safe for mechanical design of robot system.