• Progress in Medical Physics
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• v.23 no.3
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• pp.162-168
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• 2012

In proton therapy, in vivo dose verification is one of the most important parts to fully utilize characteristics of proton dose distribution concentrating high dose with steep gradient and guarantee the patient safety. Currently, in order to image the proton dose distribution, a prompt gamma distribution detection system, which consists of an array of multiple CsI(Tl) scintillation detectors in the vertical direction, a collimator, and a multi-channel DAQ system is under development. In the present study, the optimal design of prompt gamma distribution detection system was studied by Monte Carlo simulations using the MCNPX code. For effective measurement of high-energy prompt gammas with enough imaging resolution, the dimensions of the CsI(Tl) scintillator was determined to be $6{\times}6{\times}50mm^3$. In order to maximize the detection efficiency for prompt gammas while minimizing the contribution of background gammas generated by neutron captures, the hole size and the length of the collimator were optimized as $6{\times}6mm^2$ and 150 mm, respectively. Finally, the performance of the detection system optimized in the present study was predicted by Monte Carlo simulations for a 150 MeV proton beam. Our result shows that the detection system in the optimal dimensions can effectively measure the 2D prompt gamma distribution and determine the beam range within 1 mm errors for 150 MeV proton beam.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.69-83
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• 2006

A Level 3 reliability analysis has been performed for wave run-up and overtopping on a sloping seawall. A Monte-Carlo simulation was performed considering the uncertainties of various variables affecting the wave overtopping event. The wave overtopping probability was evaluated from the individual wave run-up by using the wave-by-wave method, while the mean overtopping rate was calculated directly from the significant wave height. Using the calculated overtopping probability and mean overtopping rate, the maximum overtopping volume was also calculated on the assumption of two-parameter Weibull distribution of individual wave overtopping volume. In addition, by changing wave directions, depths, and structure slopes, their effects on wave overtopping were analyzed. It was found that, when the variability of wave directions is considered or the water depth decreases toward shore, wave height become smaller due to wave refraction, which yields smaller mean overtopping rate, overtopping probability and maximum overtopping volume. For the same mean overtopping rate, the expected overtopping probability increases and the expected maximum overtopping volume decreases as approaching toward shore inside surfzone.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.253-263
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• 1993

Climatological informations have not been fully utilized by agricultural research and extension workers in Korea due mainly to inaccessbilty to the archived climate data. This study was initiated to improve access to historical climate data gathered from 72 weather stations of Korea Meteorological Administration for agricultural applications by using a microcomputer-based methodology. The climatological elements include daily values of average, maximum and minimum temperature, relative humidity, average and maximum wind speed, wind direction, evaporation, precipitation, sunshine duration and cloud amount. The menu-driven, user-friendly data retrieval system(CLIDAS) provides quick summaries of the data values on a daily, weekly and monthly basis and selective retrieval of weather records meeting certain user specified critical conditions. Growing degree days and potential evapotranspiration data are derived from the daily climatic data, too. Data reports can be output to the computer screen, a printer or ASCII data files. CLIDAS can be run on any IBM compatible machines with Video Graphics Array card. To run the system with the whole database, more than 50 Mb hard disk space should be available. The system can be easily upgraded for further expansion of functions due to the module-structured design.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.595-603
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• 2013

Touchscreen is now installed in the majority of information devices thanks to the developed digital technology. In case of copiers, although touchscreen was installed earlier than any other information device, current user interface indicates that conventional methods have been maintained without any special re-validation. But, since common office devices such as copiers have brief usage time and clear, straightforward purposes, user experience between an user and device is perhaps an important element. Nevertheless, conservativeness of the market and the fact that users and buyers are not always the same are a stumbling block to actively changing UI. Recently, however, as hardware element, buttons, have moved to touchscreen mostly for smartphone, and common and public devices have seen rapid changes in UX, mostly with touchscreen, it has led to high demand for changes in UX of copiers. To remedy the issues with copiers, a literature review was conducted through existing studies and user evaluation based on user survey and prototype was done to examine the copier's UI elements and relevant changes in usage. In particular, a new direction for UX of copiers was suggested by analyzing the impact of differences between software button-oriented UI and hardware button-oriented UI on users and usability. This study findings could be used as basic data for improving the usability of future common devices including copier and UX design.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.499-512
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• 2020

The development of the economy and network environment has a great impact on physical stores, and physical bookstores are gradually upgrading and transforming with the pace of the times. This study takes the modern bookstore under the concept of the third space as the research object. The purpose of it is to understand the needs of consumers for the space of the modern bookstores, explore the characteristics and development direction of them, which provides theoretical guidance for the follow-up development of the modern bookstore. Based on the concept of the third space and the theory of lifestyle shops and reorganizing theoretical investigation and prior research, the researcher extracts the characteristic elements of modern bookstores in line with the concept of the third space. Moreover, the research analyzes five bookstores opened in large-scale commercial facilities after 2010 as research cases. Through the analysis of the results, it shows that the modern bookstore is a multi-functional and compounded space which is gradually transformed from a single bookseller to a seller of selling lifestyle proposal. And through the analysis of big data to predict the changes in market consumption, we can find out the different needs of consumers, so as to carry out the targeted design of bookstore space and then improve the value of it. In the context of the co-development of economy and culture, the transformation of modern bookstores actually conforms to the change of consumer demand and realizes a virtuous circle.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.2
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• pp.85-95
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• 2009

The fishing lamp is a fishing gear that gathers fish at night. But the cost of oil, which is used to light fishing lamp, has been risen significantly up to 30-40% of total fishing costs. Therefore it is very urgent to develop an energy economical fishing lamp in order to solve the business difficulties of fisheries. Under this background, this research aims at developing a fishing lamp for squid jigging and hairtail angling fishery using the LED, which has excellent energy efficiency and durability. The LED fishing lamp developed can be controlled to fix a fit direction of fish shoal deep because a fishing lamp can be adjustable up and down directions. One unit of fishing lamp has about an 80Watt capacity and the frame of fishing lamp is made of aluminium to emit generated heat of LED to outside. The LED lamp developed was highly durable, only 5.7% of emitting efficiency decreased for 18 months. The illuminance of a unit LED lamp was 2,070lux at 1m and 21lux at 10 m distance, and the intensity of LED lamp system emitted 2,580lux and 400lux at the respective distances. After development of this fishing lamp, 100 units are installed on operating fishing vessels. Experimental results show that energy consumption of squid jigging and hairtail angling was reduced by 40% and 87%, respectively. In conclusion, our methods showed elevated fishing power, compared with traditional fishing method: 37.7% for squid jigging and 24.5% for hairtail angling.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.235-240
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• 2010

Purpose: In this study, we proposed a simple accommodation-dependent crystalline lens with a constant volume and homogeneous refractive index. Methods: We proposed a human crystalline lens with two aspheric surfaces. Two surfaces intersect in two points and straight line between two points was equator(2b). It assumed that the derivative in axial direction was zero at the equator and the radial derivative was zero at the vertex. Proposed human crystalline lens was divided by the equator into the anterior and posterior parts. It was assume that the volume of each part and refractive index of the human crystalline lens were constant during accommodation. Results: For the changes during accommodation, geometrical parameters were determined by different objective distances. Considering the constant volume of each part with the small decrement of the equator, we obtained the paraxial parameters, such as the anterior and posterior vertex radius of curvature and lens thickness. Compared with the experimental data published in the literature, calculated values using simple approximation showed similar change per accommodative stimulus. Conclusions: These results showed that proposed simple approximation using assumption of constant volume and refractive index of the human crystalline lens made it possible to predict changes of geometrical parameters during accommodation.

• Journal of Astronomy and Space Sciences
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• v.31 no.3
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• pp.277-283
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• 2014

Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of $33.4^{\circ}$ was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.688-701
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• 2020

In this study, a total of 68 domestic and international papers were selected from 1993 to August 2020 in order to examine the research trends related to artificial intelligence for the visually impaired. The papers were compared and analyzed by the number of papers published by year, research method, research topic, keyword analysis status, research type, and implementation method. As a result of the study, the number of papers during the study period seemed to increase steadily. But in the case of domestic research, It can be seen that it has become active since 2016. As for research methods, development research accounted for 89.7% of both domestic and foreign research. Keywords was in Visually Impaired, Deep Learning, and Assistive Device order in domestic research. And it was in Visually Impaired, Deep learning, Artificial intelligence order in foreign research. There was a difference in the frequency of words. Research type were Design, development and implementation both in domestic and foreign. Implementation method were in System 13.2%, Solution 7.4%, App. 4.4% order in domestic research, and it was in System 32.4%, App. 13.2%, Device 7.4% order in foreign research. As for the applied technology of the implementation method, were in YOLO 2.7%, TTS 2.1%, Tensorflow 2.1% order in domestic research, and it was used in CNN 8.0%, TTS 5.3%, MS-COCO 4.3% order in foreign research. The purpose of this study was to compare and analyze the trends of artificial intelligence-related research targeting the visually impaired, to immediately know the current status of domestic and foreign research, and to present the direction of artificial intelligence research for the visually impaired in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.549-557
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• 2017

Numerical studies have been carried out on scrubbers, which are after-treatment devices to satisfy strengthened emission regulations for sulfur dioxide and particulate matter. We investigated the problems with existing scrubbers through numerical analysis and designed and analyzed a new swirl-type scrubber that could solve these problems. As a result, with the swirl-type scrubber, exhaust gas formed a vortex in the lower part of the device, and some of this gas was released along the guide vane through the bottom surface. In this case, the pressure gradient in the vertical direction was not large, but a pressure difference between the inside and outside of the baffle was generated. The shape of the exhaust gas stream was investigated, and when water was not sprayed, the exhaust gas flowed constantly to the outlet along the guide vane, in contrast to when water was sprayed. It was confirmed that the shape of the flow was influenced by the guide vane, nozzle arrangement and water pressure. In the case of the swirl-type scrubber, impact on engine back-pressure was minimal, because differential pressure at the inlet and outlet was less than half of that with a conventional scrubber.