• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.525-532
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• 2016

High-energy linear accelerators are increasingly used in the medical field. However, the unwanted photo-neutrons can also be contributed to the dose delivered to the patients during their treatments. In this study, neutron fluxes were measured in a solid water phantom placed at the isocenter 1-m distance from the head of an18-MV linac using the foil activation method. The produced activities were measured with a calibrated well-type Ge detector. From the measured fluxes, the total neutron fluence was found to be $(1.17{\pm}0.06){\times}10^7n/cm^2$ per Gy at the phantom surface in a $20{\times}20cm^2$ X-ray field size. The maximum photo-neutron dose was measured to be $0.67{\pm}0.04$ mSv/Gy at $d_{max}=5cm$ depth in the phantom at isocenter. The present results are compared with those obtained for different field sizes of $10{\times}10cm^2$, $15{\times}15cm^2$, and $20{\times}20cm^2$ from 10-, 15-, and 18-MV linacs. Additionally, ambient neutron dose equivalents were determined at different locations in the room and they were found to be negligibly low. The results indicate that the photo-neutron dose at the patient position is not a negligible fraction of the therapeutic photon dose. Thus, there is a need for reduction of the contaminated neutron dose by taking some additional measures, for instance, neutron absorbing-protective materials might be used as aprons during the treatment.

• Fire Science and Engineering
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• v.31 no.2
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• pp.119-126
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• 2017

This study examined the soundness, vibration, and size of ambulances currently used in Korea as well as the comfort and convenience of ambulancesin Korea. The target vehicles were measured and investigated using the currently used freight type, van type, and Benz ambulance. Currently, the ambulance standards in Korea have only formal production standards, and there is no regulation on safety for ambulances, space regulation for first aid, comfort, and convenience. Therefore, comparative experiments on the comfort and convenience were measured using noise and vibration measurement experiments, and research was conducted on the size and interior rearrangement of ambulances to investigate the areas that can improve the comfort and convenience. The noise measurementsshowed that the noise was large in the order of the van type, Benz type, and freight type. In the case of a speed of 40 km/h or more, the noise measurement result was 60 to 70 dB or more. In the case of vibration, the Benz type and van type ambulance were good, and the vibration of the freight type showed the worst result, highlighting the need for improvement. Lastly, it is not possible to increase the internal size of the structure of domestic ambulance. On the other hand, it is important that through ambulance relocation and the position of first aid personnel, it will be possible to use it more comfortably and conveniently.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.2
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• pp.33-38
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• 2020

In the photoelectrochemical (PEC) water splitting, GaN is one of the most promising photoanode materials due to high stability in electrolytes and adjustable energy band position. However, the application of GaN is limited because of low efficiency. To improve solar to hydrogen conversion efficiency, we introduce a Cobalt Phosphate (Co-pi) catalyst by photo-electrodeposition. The Co-pi deposition GaN were characterized by SEM, EDS, and XPS, respectively, which illustrated that Co-pi was successfully decorated on the surface of GaN. PEC measurement showed that photocurrent density of GaN was 0.5 mA/㎠ and that of Co-pi deposited GaN was 0.75 mA/㎠. Impedance and Mott-Schottky measurements were performed, and as a result of the measurement, polarization resistance (R_p) and increased donor concentration (N_D) values decreased from 50.35 Ω to 34.16 Ω were confirmed. As a result of analyzing the surface components before and after the water decomposition, it was confirmed that the Co-pi catalyst is stable because Co-pi remains even after the water decomposition. Through this, it was confirmed that Co-pi is effective as a catalyst for improving GaN efficiency, and when applied as a catalyst to other photoelectrodes, it is considered that the efficiency of the PEC system can be improved.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.57-65
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• 2019

Purpose: The purpose is to clarify the effect of additional scattering ratio on the edge of the block according to the increasing block thickness with low melting point lead alloy and pure lead in electron beam therapy. Methods and materials: $10{\times}10cm^2$ Shielding blocks made of low melting point lead alloy and pure lead were fabricated to shield mold frame half of applicator. Block thickness was 3, 5, 10, 15, 20 (mm) for each material. The common irradiation conditions were set at 6 MeV energy, 300 MU / Min dose rate, gantry angle of $0^{\circ}$, and dose of 100 MU. The relative scattering ratio with increasing block thickness was measured with a parallel plate type ion chamber(Exradin P11) and phantom(RW3) by varying the position of the shielding block(cone and on the phantom), the position of the measuring point(surface ans depth of $D_{max}$), and the block material(lead alloy and pure lead). Results : When (depth of measurement / block position / block material) was (surface / applicator / pure lead), the relative value(scattering ratio) was 15.33 nC(+0.33 %), 15.28 nC(0 %), 15.08 nC(-1.31 %), 15.05 nC(-1.51 %), 15.07 nC(-1.37 %) as the block thickness increased in order of 3, 5, 10, 15, 20 (mm) respectively. When it was (surface / applicator / alloy lead), the relative value(scattering ratio) was 15.19 nC(-0.59 %), 15.25 nC(-0.20 %), 15.15 nC(-0.85 %), 14.96 nC(-2.09 %), 15.15 nC(-0.85 %) respectively. When it was (surface / phantom / pure lead), the relative value(scattering ratio) was 15.62 nC(+2.23 %), 15.59 nC(+2.03 %), 15.53 nC(+1.67 %), 15.48 nC(+1.31 %), 15.34 nC(+0.39 %) respectively. When it was (surface / phantom / alloy lead), the relative value(scattering ratio) was 15.56 nC(+1.83 %), 15.55 nC(+1.77 %), 15.51 nC(+1.51 %), 15.42 nC(+0.92 %), 15.39 nC(+0.72 %) respectively. When it was (depth of $D_{max}$ / applicator / pure lead), the relative value(scattering ratio) was 16.70 nC(-10.87 %), 16.84 nC(-10.12 %), 16.72 nC(-10.78 %), 16.88 nC(-9.93 %), 16.90 nC(-9.82 %) respectively. When it was (depth of $D_{max}$ / applicator / alloy lead), the relative value(scattering ratio) was 16.83 nC(-10.19 %), 17.12 nC(-8.64 %), 16.89 nC(-9.87 %), 16.77 nC(-10.51 %), 16.52 nC(-11.85 %) respectively. When it was (depth of $D_{max}$ / phantom / pure lead), the relative value(scattering ratio) was 17.41 nC(-7.10 %), 17.45 nC(-6.88 %), 17.34 nC(-7.47 %), 17.42 nC(-7.04 %), 17.25 nC(-7.95 %) respectively. When it was (depth of $D_{max}$ / phantom / alloy lead), the relative value(scattering ratio) was 17.45 nC(-6.88 %), 17.44 nC(-6.94 %), 17.47 nC(-6.78 %), 17.43 nC(-6.99 %), 17.35 nC(-7.42 %) respectively. Conclusions: When performing electron therapy using a shielding block, the block position should be inserted applicator rather than the patient's body surface. The block thickness should be made to the minimum appropriate shielding thickness of each corresponding using energy. Also it is useful that the treatment should be performed considering the influence of scattering dose varying with distance from the edge of block.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.2
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• pp.159-164
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• 2013

It is well known that a single moving camera video is capable of extracting the 3-dimensional position of an object. With this in mind, current research performed image-based monitoring to establish a floating structure model using a camcorder system. Following this, the present study extracted frame images from digital camcorder video clips and matched the interest points to obtain relative 3D coordinates for both regular and irregular wave conditions. Then, the researchers evaluated the transformation accuracy of the modified SURF-based matching and image-based displacement estimation of the floating structure model in regular wave condition. For the regular wave condition, the wave generator's setting value was 3.0 sec and the cycle of the image-based displacement result was 2.993 sec. Taking into account mechanical error, these values can be considered as very similar. In terms of visual inspection, the researchers observed the shape of a regular wave in the 3-dimensional and 1-dimensional figures through the projection on X Y Z axis. In conclusion, it was possible to calculate the displacement of a floating structure module in near real-time using an average digital camcorder with 30fps video.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.2
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• pp.123-129
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• 2013

Purpose: The way check the movement of the fiducial marker insertion in the treatment of patients with prostate cancer. However the existing methods of fiducial marker verification process difficult to identify the specific location of the marker behind the femur and pelvic bone. So to study the evaluation of maker match with using kilo voltage (KV) X-ray by On-board imager to both oblique verification method. Materials and Methods: Five patients were selected for rectal ballooning and inserted fiducial marker. Compare the position of the fiducial marker of reference plan 2D/2D Anterior/Posterior verification method and 2D/2D both oblique verification method. So to measurement the shift score of X, Y, Z (axis) and measure exposure dose given to patients and compare matching time. Results: 2 dimensional OBI KV X-ray imaging using two-dimensional matching image are orthogonal, so locating fiducial marker matching clear and useful DRR (digital reconstruction radiography) OBI souce angle ($45^{\circ}/315^{\circ}$) matching most useful. 2D/2D both oblique verification method was able to see clearly marker behind the pelvic bone. Also matching time can be reduced accordingly. According to the method of each matching results for each patient in each treatment fraction, X, Y, and Z axis the Mean $value{\pm}SD$ (standard deviation) is X axis (AP/LAT: $0.4{\pm}1.67$, OBLIQUE: $0.4{\pm}1.82$) mm, Y axis (AP/LAT: $0.7{\pm}1.73$, OBLIQUE: $0.2{\pm}1.77$) mm, Z axis (AP/LAT: $0.8{\pm}1.94$, OBLIQUE:$1.5{\pm}2.8$) mm. In addition, the KV X-ray source dose radiation exposure given to the patient taking average when AP/LAT matching is (0.1/2.1) cGY, when $315^{\circ}/45^{\circ}$ matching is (0.27/0.26) cGY. Conclusion: In conclusion for inserted fiducial marker of prostate cancer patients 2D/2D both oblique matching method is more accurate verification than 2D/2D AP/LAT matching method. Also the matching time less than the 2D/2D AP/LAT matching method. Taken as the amount of radiation exposure to patients less than was possible. Suggest would improve the treatment quality of care patients more useful to establish a protocol such as case.

• Journal of Korean Society of Disaster and Security
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• v.9 no.1
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• pp.33-38
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• 2016

Real time location system was development for safety management at road and bridge maintenance field. The system can check the real-time location detection, movement history, behavior of a number of laborers. The system consisted of a Bluetooth and ZigBee that uses low-power. It had a very large error that the previous method for the position recognition by triangulation using the RSSI. Because This study proposed a new distance measurement and correction scheme using RSSI and accelerometer. It was evaluated in the maintenance field. A development system were evaluated in the field, the results are shown an error between 0.2 m and 0.4 m. And through the acceleration of history it was confirmed by determining possible to determine the safety situation of the laborers.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.25-31
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• 2009

Purpose: Evaluate the mold we have made to improve the reproducibility of the patient position and make homogeneous dose distribution to the treatment volume effectively when treating the patient who has hypervascular ulcer on her tongue caused by paraneoplastic autoimmune multiorgan syndrome by mold brachytherapy. Materials and Methods: The mold is consisted of upper and lower parts. We inserted 2 mm of lead sheet on the gums toward the oral cavity to protect them from unnecessary irradiation during the treatment. We had planned on orthogonal images obtained the patient. 200 cGy was delivered in every fraction with a total dose of 3000 cGy. To evaluate the effect of the lead sheet, we made a measurement with a phantom that has gums and tongue made of tissue with an equivalent material (bolus). Five of TLDs were placed on the interesting points of gums to measure the dose during irradiation with lead sheet and without lead sheet for three times respectively. Results: The result of the measurement without lead sheet are A: 33.9 cGy, B: 30.1 cGy, C: 31.8 cGy, D: 23.3 cGy, E: 24.1 cGy. The results of measurement with lead sheet are A: 20.6 cGy, B: 18.8 cGy, C: 19.6 cGy, D: 14.7 cGy, E: 15.1 cGy. Conclusion: Since we are using the mold made in our department during the treatment of the patient with hypervascular ulcer on tongue, we could deliver a proper dose to the treatment volume. In addition, the mold provided highly accurate and reproducible treatment and reduced the dose to the gums and teeth. Therefore, the possibility of side effects could be decreased significantly.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.2
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• pp.20-30
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• 1999

We have made the single side hand filter for the dual channel receiver which is a heterodyne receiver to observe the cosmic radio waves with 100GHz band ranged from 85GHz to 115GHz and 150GHz band ranged from 125GHz to 175GHz simultaneously. We have introduced the filter theory using the principle of the Martion-Puplett interferometer, which has the characteristics of rotated polarization. To reduce the loss of the transmission and beam coupling which are caused from the path difference associated with the intermediate frequency the design and the implementation have been intensely considered. The receiver needs two filters with different characteristics each other. Because each of them has the optimum positions as a function frequency at which the signal frequency is fed to mixer and the image frequency is rejected to the image termination load. The intermediate frequency and its band width have been also evaluated. We have measured the property of two filters using the vector network analyser and the beam measurement system which is made by us. The responses of the filter as a function of the position and the frequency are compared with the theory. It is shown that not only the measured values are very close to the theoretical values, but also the image rejection ratios are better than 22dB for both filters. Through successful observation using a dual channel receiver with two manufactured filters, the performance of the filters has finally verified.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.603-612
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• 2006

Recently the web service area is rapidly growing as the next generation IT paradigm because of increase of concern about SOA(Services-Oriented Architecture) and growth of B2B market. Since a service discovery through UDDI(Universal Description, Discovery and Integration) is limited to a functional requirement, it is not considered an effect on frequency of service using and reliability of mutual relation. That is, a quality as nonfunctional aspect of web service is regarded as important factor for a success between consumer and provider. Therefore, the web service selection method with considering the quality is necessary. This paper suggests the agent-based quality broker architecture and selection process which helps to find a service providing the optimum quality that the consumer needs in a position of service consumer. A theory of agent is accepted widely and suitable for proposed system architecture in the circumstance of distributed and heterogeneous environment like web service. In this paper, we considered the QoS and CoS in the evaluation process to solve the problem of existing researches related to the web service selection and used PROMETHEE(Preference Ranking Organization MeTHod for Enrichment Evaluations) as an evaluation method which is most suitable for the web service selection among MCDM approaches. PROMETHEE has advantages that solve the problem that a pair-wise comparison should be performed again when comparative services are added or deleted. This paper suggested a case study with the service composition scenario in order to verify the selection process. In this case study, the decision making problem was described on the basis of evaluated values for qualities from a consumer's point of view and the defined service level.