• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.148-156
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• 2020

The paper is a summary of the results of the basic pullout test which is conducted to evaluate the anchorage capacity of high strength headed bars that is mechanical anchored vertically on steel fiber reinforced concrete members. The main experimental parameters are volume fraction of steel fiber, concrete strength, anchorage length, yield strength of headed bars, and shear reinforcement bar. Both sides of covering depth of the specimen are planned to double the diameter of the headed bars. The hinged point is placed at the position of each 1.5𝑙_dt and 0.7𝑙_dt around the headed bars, and the headed bars are drawn directly. As a result of pullout test experiment, concrete fracture and steel tensile rupture appear by experimental parameters. The compressive strength of concrete is 2.7~5.4% higher than that of steel fiber with the same parameters, while the pullout strength is 20.9~63.1% higher than that of steel fiber without the same parameters, which is evaluated to contribute greatly to the improvement of the anchorage capacity. The reinforcements of shear reinforcements parallel to the headed bars increased 1.7~7.7% pullout strength for steel fiber reinforced concrete, but the effect on the improvement of the anchorage capacity was not significant considering the increase in concrete strength. As with the details of this experiment, it is believed that the design formula for the anchorage length of KCI2017and KCI2012 are suitable for the mechanical development design of SD600 head bar that is perpendicular to the steel fiber reinforced concrete members.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.178-188
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• 2019

When using a distributed system, it is very important to know the intention of a target ship in order to prevent collisions. The action taken by a certain ship for collision avoidance and the action of the target ship it intends to avoid influence each other. However, it is difficult to establish a collision avoidance plan in consideration of multiple-ship situations for this reason. To solve this problem, a Distributed Stochastic Search Algorithm (DSSA) has been proposed. A DSSA searches for a course that can most reduce cost through repeated information exchange with target ships, and then indicates whether the current course should be maintained or a new course should be chosen according to probability and constraints. However, it has not been proven how the parameters used in DSSA affect collision avoidance actions. Therefore, in this paper, I have investigated the effect of the parameters and weight factors of DSSA. Experiments were conducted by combining parameters (time window, safe domain, detection range) and weight factors for encounters of two ships in head-on, crossing, and overtaking situations. A total of 24,000 experiments were conducted: 8,000 iterations for each situation. As a result, no collision occurred in any experiment conducted using DSSA. Costs have been shown to increase if a ship gives a large weight to its destination, i.e., takes selfish behavior. The more lasting the expected position of the target ship, the smaller the sailing distance and the number of message exchanges. The larger the detection range, the safer the interaction.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.76-83
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• 2018

In order to prevent overusing the fishing gear and to reduce discarded fishing gear, there is a need for a technique that can efficiently transmit the information including the type and location of the fishing gear and the user's real name to the fishing boat and the control center using IoT-based communication. In order to do this, it is necessary to be able to confirm the position information of a plurality of buoys that can be identified by the base stations on the land. In this paper, in order to service the maritime IoT communication system, we calculate the link budget between the land base station and the targets on the sea to derive the service coverage. To design a marine IoT radio network for building a fishing gear monitoring system, we calculate link budget for wireless service optimization at sea for NB-IoT using 1.8 GHz frequency band and LoRa service using 900 MHz frequency band. In addition, the link budget between the land base station and buoy, the link budget between the land base station and fishing boat are calculated and the results are analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.127-133
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• 2021

A recent study of people physically falling focused on analyzing the motions of the falls using a recurrent neural network (RNN) and a deep learning approach to get good results from detecting 2D human poses from a single color image. In this paper, we investigate a detection method for estimating the position of the head and shoulder keypoints and the acceleration of positional change using the skeletal keypoints information extracted using PoseNet from an image obtained with a low-cost 2D RGB camera, increasing the accuracy of judgments about the falls. In particular, we propose a fall detection method based on the characteristics of post-fall posture in the fall motion-analysis method. A public data set was used to extract human skeletal features, and as a result of an experiment to find a feature extraction method that can achieve high classification accuracy, the proposed method showed a 99.8% success rate in detecting falls more effectively than a conventional, primitive skeletal data-use method.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.233-241
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• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.179-188
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• 1981

The authors made an investigation concerning the geographical distribution and some major differentiations in morphological characteristics associated with the each habitat, of the pond smelt, Hypomesus olidus, which was introduced into Korea more than 50 years ago. Major characteristics utilized for the comparison study were upper jaw (maxillary), number of fin rays, scale structure, vertebral count, number of pyloric caeca, number of gill rakers, and the relative measurements of these and other internal characters. 1. The main areas of natural distribution are Paro Lake, Soyang Lake, Han River, Euirim Lake, and Ogjeong Lake (or Unam Lake) and the tributaries of these waters. 2. Morphological variations varied when the mean values of measurements from each area were compared with the standard measurement value by mosaic comparison, and in some instances a significant variation was found. 3. The most significant variations were found in the number of fin rays of pectoral and anal fins; the lengths from the tip of snout to the origin of pectoral fin, from snout to ventral fin, and from snout to anal fin, relative to standard body length; eye depth relative to head length; upper jaw: the number of pyloric caeca and the scale structure. Variations, on the other hand, by each habitat were not clear in the numbers of ventral and dorsal fin rays, gill rakers, vertebrae and lateral line scale : and the depth of caudal peduncle and distance from the tip of snout to the origin of dorsal fin relative to standard body length. 4. The scales of pond smelt showed some differences in the shape of scales, the shape and position of the focus and the number of ridges according to the scale positions on the body. No radii were present. The relations between longitudinal and transverse diameters of the scale suggest that the pond smelts of Soyang Lake and Un-am Lake are closely related, and those of Han River and Euirim Lake are also closely related. 5. The geographical variations in morphology of the pond smelt seem to have resulted from the variations in turbidity, water temperature, salinity (rather conductivity) and currents. 6. From the results obtained, it may be concluded that such factors as supramaxillary, relation between scale length and its breadth, number of caudal vertebrae and eye depth relative to head length may be used as the key characters for the classification of geographical varieties of Pond smelt.

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.2
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• pp.83-89
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• 2008

Purpose: The checking method of target and normal structure are used by MVCBCT, KVCBCT, CT On-rail System, Ultrasound in H&N cancer patient. In case of MVCT, the utilization of bone structure is valuable to check around tissue. But the utilization of soft tissue is not enough. The point of this paper is dose variation in movable parotid and changeable volume of H&N cancer patient of CT On-rail System. Materials and Methods: The object of H&N cancer patient is 5 in this hospital. The selected patient are scanned ARTISTE CT Vision (CT On-ral System) a triweekly. After CT scanning, tranfered coordinates are obtained by movable of parotid gland comparison with planning image. Checking for the changeable volume of parotid gland. A Obtained CT image are tranfered to the RTP System. So dose variation are checked by following changed volume. Results: The changes of target coordinate by the parotid gland movement are X: -0.4~0.4 cm, Y: -0.4~0.3 cm, Z: -0.3~0.3 cm. the volume of GTV is decreased to about 7.11%/week and then both parotid gland volume are shrinked about 4.81%/week (Lt), 2.91%/week (Rt). At the same time, each parotid gland are diminished in radiation dose as 3.66%/week (Lt), 2.01%/week. Conclusion: Images from CT on the rail System which are able to aquire the better quality images of soft tissue in Target area than MVCBCT. After replanning and dose redistribution by required images, It could gain not only the correction of the patient set-tup errors but exact dose distribution. Accordingly, the delivery of compensated dose, It makes that we could do Adaptive Targeting Radiotherapy and need Real Time Adaptive Targeting Radiotherapy by reduce beam delivary time.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.335-343
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• 2012

Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photonueutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photonbeams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose.

• Progress in Medical Physics
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• v.14 no.2
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• pp.90-98
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• 2003

Purpose : A new virtual simulation technique for craniospinal irradiation (CSI) that uses a CT-simulator was developed to improve the accuracy of field and shielding placement as well as patient positioning. Materials and Methods : A CT simulator (CT-SIM) and a 3-D conformal radiation treatment planning system (3D-CRT) were used to develop CSI. The head and neck were immobilized with a thermoplastic mask while the rest of the body was immobilized with a Vac-Loc. A volumetric image was then obtained with the CT simulator. In order to improve the reproducibility of the setup, datum lines and points were marked on the head and body. Virtual fluoroscopy was performed with the removal of visual obstacles, such as the treatment table or immobilization devices. After virtual simulation, the treatment isocenters of each field were marked on the body and on the immobilization devices at the conventional simulation room. Each treatment fields was confirmed by comparing the fluoroscopy images with the digitally reconstructed radiography (DRR) and digitally composited radiography (DCR) images from virtual simulation. Port verification films from the first treatment were also compared with the DRR/DCR images for geometric verification. Results : We successfully performed virtual simulations on 11 CSI patients by CT-SIM. It took less than 20 minutes to affix the immobilization devices and to obtain the volumetric images of the entire body. In the absence of the patient, virtual simulation of all fields took 20 min. The DRRs were in agreement with simulation films to within 5 mm. This not only reducee inconveniences to the patients, but also eliminated position-shift variables attendant during the long conventional simulation process. In addition, by obtaining CT volumetric image, critical organs, such as the eyes and the spinal cord, were better defined, and the accuracy of the port designs and shielding was improved. Differences between the DRRs and the portal films were less than 3 m in the vertebral contour. Conclusion : Our analysis showed that CT simulation of craniospinal fields was accurate. In addition, CT simulation reduced the duration of the patient's immobility. During the planning process. This technique can improve accuracy in field placement and shielding by using three-dimensional CT-aided localization of critical and target structures. Overall, it has improved staff efficiency and resource utilization by standard protocol for craniospinal irradiation.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.198-221
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• 2009

Royal tombs of Joseon dynasty are the crystallization of history, ideology, culture, art, architecture, and ritual ceremony of Joseon dynasty, all mingled in one. So, they are very significant symbols showing 500 years of dynastic history as a whole. Among various factors comprising a royal tomb, stone figures surrounding grave mound are special factors as a symbol protecting it. Further among them, twelve zodiac images arrayed nearest to the grave mound represent the core of the function. Images of twelve zodiac signs originated from the tombs of the Unified Silla Kingdom are certain to hold important role and position in the construction of royal tombs, judging from huge scale and excellent sculptural art of them. However, both their scale and form had been gradually simplified in Goryeo and Joseon dynasty, thus the importance of them has been underestimated compared to other stone figures Images of twelve zodiac signs were very important factors which decorated royal tombs both as a protective role and as a concept of direction. Their historicity and symbolism cannot be neglected in that they had been transmitted to the royal tombs of Joseon dynasty. In this paper, images of twelve zodiac signs expressed in the royal tombs of Joseon dynasty are classified into 3 forms, and reviewed the origin and development of them for each period. They could be classified into 3 forms ; civil vassals with human body and head, civil vassals with human body and head wearing hat decorated with zodiac animals, Chinese characters of either zodiac signs or either a combination of 10 calendar signs and 8 trigrams. The above 3 forms originated from China and became a favorite motif to decorate the royal tombs from early Joseon period until late Joseon by replacing each other and thus changing along the course of the dynasty. In the meantime, we can see a unique character in the images of twelve zodiac signs of royal tombs of Joseon dynasty. In some cases, 24 directions are expressed in which 10 calender signs and 8 trigrams are composed altogether. Images of twelve zodiac signs in the royal bombs of Joseon dynasty are very significant as evidences by which we can confirm uniqueness and tradition of Korean tomb system transmitted from Unified Silla period.