• Title/Summary/Keyword: 동기획득

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Evaluation of using Gantry Tilt Scan to Head & Neck of Patients during Radiation Therapy for Reduction of Metal Artifact (Head & Neck 환자의 방사선 치료시 Metal Artifact의 감소를 위한 Gantry Tilt Scan의 유용성 평가)

  • Lee, Chung-Hwan;Yun, In-Ha;Hong, Dong-Gi;Back, Geum-Mun;Kwon, Gyeong-Tae
    • The Journal of Korean Society for Radiation Therapy
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    • v.22 no.2
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    • pp.85-95
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    • 2010
  • Purpose: The degradation of an image quality and error of the beam dose calculation can be caused because the metal artifact is generated during the CT simulation of head and neck patient. The usability of the gantry tilt scan for reducing the metal artifact tries to be appraised. Materials and Methods: The inferior $20^{\circ}$ gantry tilt scan was made in order to reduce the metal artifact and $0^{\circ}$ reconstruction image was acquired. The AAPM CT performance Phantom was used in order to compare the CT number of the reconstructed image and Original image. the difference of volume was compared by using the acrylic phantom. The homogeneity of the CT number was evaluated the Intensity volume Histogram (IVH) as in order to evaluate an influence by the metal artifact. A dose was evaluated as the Dose Volume Histogram (DVH). Results: in the comparison of the CT number and volume, the difference showed up less than 0.5%. As to the comparison of IVH, in the gantry tilt scan, influence by an artifact was reduced and the homogeneity of the CT number was improved. The comparison of DVH result reduced the mean dose error of the both sides parotid 0.2~6%. Conclusion: In the Head & Neck radiation therapy, It is difficult and to distinguish tumor and normal tissue and the error of dose is generated by the metal artifact. The delineation of the exact organization was possible if the Gantry tilt scan was used. The CT number homogeneity was improved and the error of dose could be reduced. The Gantry tilt scan confirmed in the Head & Neck radiation therapy to be very useful in the exact radiation therapy.

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Preparatory Research prior to the Development of Consumer-Tailored 3D Printing Service Platform (소비자 맞춤형 삼차원 프린팅 서비스 플랫폼 개발을 위한 탐색)

  • Lee, Guk-Hee;Choi, Hye-Kyong
    • Science of Emotion and Sensibility
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    • v.20 no.1
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    • pp.3-16
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    • 2017
  • With the development and proliferation of three-dimensional(3D) printers, consumers in modern society can now print products of what they want three-dimensionally at home. However, consumers themselves would have to produce digital design maps that are compatible with 3D printers and to set up the optimum printing quality and temperature, as well as to pay for maintenance and repair of 3D printers and to respond to any possible lawsuits related to intellectual property right about designs in order to make possible consumer-tailored manufacturing through 3D printing. However, in reality, since it is very difficult for consumers to respond to these issues, it is necessary to develop services that perform 3D printing on behalf of consumers in the desired direction. Motivated by this objective, this study investigated user experiences on Shapeways(www.shapeways.com), which is a global online 3D printing product and sales companies, from many viewpoints in order to obtain insight into 3D printing services and modes which were preferred by consumers. The study result showed that quantitative evaluations on usability, search process, price adequacy, re-visit intention, diversity of design, and satisfaction of design was scored low overall. Furthermore, this study acquired insight about consumer-tailored 3D printing services through constructive suggestions on multi-language support, openness of manufacturing process, simultaneous operation of online and offline sites, design-oriented consumer-tailored manufacturing service, services that ensure delivery safety and product durability, and surface finishing services. This study is expected to provide a wide range of opinions not only on 3D printing service platform development but also on related industry and research.

Three-Dimensional Image Display System using Stereogram and Holographic Optical Memory Techniques (스테레오그램과 홀로그래픽 광 메모리 기술을 이용한 3차원 영상 표현 시스템)

  • 김철수;김수중
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.6B
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    • pp.638-644
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    • 2002
  • In this paper, we implemented a three dimensional image display system using stereogram and holographic optical memory techniques which can store many images and reconstruct them automatically. In this system, to store and reconstruct stereo images, incident angle of reference beam must be controlled in real time, so we used BPH(binary phase hologram) and LCD(liquid crystal display) for controlling reference beam. The reference beams are acquired by Fourier transform of BPHs which designed with SA(simulated annealing)algorithm, and the BPHs are represented on the LCD with the 0.05 seconds time interval using application software for reconstructing the stereo images. And input images are represented on the LCD without polarizer/analyzer for maintaining uniform beam intensities regardless of the brightness of input images. The input images and BPHs are edited using application software(Photoshop) with having the same recording scheduled time interval in storing. The reconstructed stereo images are acquired by capturing the output images with CCD camera at the behind of the analyzer which transforms phase information into brightness information of images. In output plane, we used a LCD shutter that is synchronized to a monitor that display alternate left and right eye images for depth perception. We demonstrated optical experiment which store and reconstruct four stereo images in BaTiO$_3$ repeatedly using the proposed holographic optical memory techniques.

A Study on the Characteristics of Bonsai Industry in Korea, China and Japan (한·중·일 분재산업의 특성에 관한 연구)

  • Yoo, Su-Hyung;Jeong, Joon-Rae;Park, Yool-Jin
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.37 no.3
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    • pp.119-126
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    • 2019
  • For this purpose, research was made to look into the style, material, organization, and legal as well as institutional system of the bonsai industry in the three countries. In order to understand what significance it has and how it has changed historically, related literature was surveyed and questionnaires were distributed to the concerned people to collect the data needed for them to plan bonsai industry. The results of the survey are as follows. Analysis of awareness of bonsai culture, respondents replied that the motive and purpose of bonsai is because they like flower trees, and the technical information about bonsai is usually obtained by visits to bonsai gardens. The analysis revealed that respondents usually join more than one bonsai club and are active more than once a month, which means longer than 4 hours each month, and their activities are more frequently in the metropolitan area. From the analysis of preference for bonsai culture, it was made known that the favorite bonsai size is less than middle one(20~50cm), the characteristics of the favorite species are beauty. A research and analysis of bonsai-related technical education found that bonsai is trimmed manually in general, bonsai experts are usually kept in contact with, and the bonsai technique is learned through interaction with the experts.

A Global Korean Networking Strategy for Tourism-related Firms' Internationalization (관광관련기업의 국제화를 위한 글로벌 코리안 네트워킹 전략)

  • Kim, Min-Sook;Bang, Ho-Yeol
    • International Commerce and Information Review
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    • v.14 no.2
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    • pp.55-79
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    • 2012
  • The previous studies based on a resource-based view of firm highlighted the role of resources within a firm in creating and sustaining competitive advantage. Recent research, however, the relational view points to the importance of inter-firm sources(or relational capital) in creating firm competitiveness. In international business field, the studies on born-global firms also states that when firms are lack of ownership-specific advantages in their internationalization process, they resort to the external partners and social networks to complement their resource scarcity. By adopting the relational view and born-global firms concept, a network-based approach needs to be applied to explain the international strategy of Korean service firms. This is because most of Korean service firms own less ownership-specific advantages than global competitors. This study proposes Korean firms' global network building and exploiting strategy to enhance their international stages of development. The network, for example, Global Korean Tourism Network, enables network members access to the valuable resources and capabilities they are lack of when undergoing internationalization process. This study's contribution is along two dimension. First, even global Korean network is emerging as a major issue in recent years, we could not figure out how to build global Korean network for service firms. This studies gives an answer. Second, we derived what benefits can be gained from the network if Global Korean Tourism Network is developed for hotel, tourism, convention firms' internationalization.

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A Cell Selection Technique Considering MIMO Precoding (MIMO 프리코딩을 고려한 셀 탐색 기법)

  • Kim, Han Seong;Hong, Tae Howan;Cho, Yong Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37A no.12
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    • pp.1076-1084
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    • 2012
  • In the CS/CB(Coordinated Scheduling/Beamforming) scheme, the cell edge user throughput is increased by selecting MIMO (Multiple Input Multiple Output) precoders which can minimize the interferences from adjacent base stations (BSs). However, in current LTE(Long Term Evolution) systems, the serving cell is selected in the initialization stage by using the synchronization signals and cell specific reference signals transmitted by adjacent BSs with a single antenna. The selected BS in the initialization stage may not be the best one since the MIMO precoding gain has not been considered in the cell selection stage. In this paper, a new cell selection technique is proposed for LTE systems with MIMO precoder by taking into account the effect of the precoder in the initialization stage. The proposed technique enables a user equipment (UE) in the cell boundary to select the serving BS by using the information (channel rank, effective channel capacity, and effective SINR(Signal to Interference plus Noise Ratio)) acquired from cell specific reference signals of candidate BSs. It is verified by computer simulation that the proposed technique can increase the channel capacity significantly in the multi-cell environments, compared with the conventional CS/CB scheme.

A CDMA Network-based Wireless System for Measuring Lap Time on a Ski Slope (CDMA 망에 기반한 스키장 슬로프의 무선 구간 기록 측정 시스템)

  • Lee, Hyung-Bong;Park, Lae-Jeong;Moon, Jung-Ho;Chung, Tae-Yun
    • The KIPS Transactions:PartD
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    • v.16D no.1
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    • pp.133-138
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    • 2009
  • This paper introduces a pilot CDMA network-based wireless lap time measurement system set up on a ski slope of Yongpyong Ski Resort. The wireless lap time measurement system is one output of U-Sports Project of Gangwon Province, which is intendended for promoting local strategic business and preparation for hosting 2018 Winter Olympic Games at Pyeongchang. A pair of laser sensors is installed at the entry and exit points of a section requiring lap time measurement on a ski slope. Each laser sensor is connected to a sensor node via wire so that the sensor node can detect the time when a skier enters or exits the section. Also each sensor node is connected to a CDMA network via a modem and receives a standard time from a NTP server. Each node executes the NTP algorithm to synchronize its local time to the received server time. As a result of the time synchronization, the sensor nodes maintain its local time within a resolution of at least 10 miliseconds and transmit the time of detection to a central control center. While the wireless lap time measurement system introduced in the paper does not need expensive measurement equipment, the system allows the central control center to provide lap time records in a more convenient manner compared to conventional manual lap time measuremnt methods.

Characteristics of Remote Sensors on KOMPSAT-I (다목적 실용위성 1호 탑재 센서의 특성)

  • 조영민;백홍렬
    • Korean Journal of Remote Sensing
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    • v.12 no.1
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    • pp.1-16
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    • 1996
  • Korea Aerospace Research Institute(KARI) is developing a Korea Multi-Purpose Satellite I(KOMPSAT-I) which accommodates Electro-Optical Camera(EOC), Ocean Color Imager(OCI), Space Physics Sensor(SPS) for cartography, ocean color monitoring, and space environment monitoring respectively. The satellite has the weight of about 500 kg and is operated on the sun synchronized orbit with the altitude of 685km, the orbit period of 98 minutes, and the orbit revisit time of 28days. The satellite will be launched in the third quarter of 1999 and its lifetime is more than 3 years. EOC has cartography mission to provide images for the production of scale maps, including digital elevation models, of Korea from a remote earth view in the KOMPSAT orbit. EOC collects panchromatic imagery with the ground sample distance(GSD) of 6.6m and the swath width of 15km at nadir through the visible spectral band of 510-730 nm. EOC scans the ground track of 800km per orbit by push-broom and body pointed method. OCI mission is worldwide ocean color monitoring for the study of biological oceanography. OCI is a multispectral imager generating 6 color ocean images with and <1km GSD by whisk-broom scanning method. OCI is designed to provide on-orbit spectral band selectability in the spectral range from 400nm to 900nm. The color images are collected through 6 primary spectral bands centered at 443, 490, 510, 555, 670, 865nm or 6 spectral bands selected in the spectral range via ground commands after launch. SPS consists of High Energy Particle Detector(HEPD) and Ionosphere Measurement Sensor(IMS). HEPD has mission to characterize the low altitude high energy particle environment and to study the effects of radiation environment on microelectronics. IMS measures densities and temperature of electrons in the ionosphere and monitors the ionospheric irregularities in KOMPSAT orbit.

Artists or Educators? : A Phenomenological Study on the Collective Identity of Future Arts & Culture Education Instructors (ACEIs) (예술가인가 교육가인가?: 문화예술교육사 국가자격증 취득희망자의 정체성에 관한 현상학적 연구)

  • Kim, InSul;Park, ChilSoon;Cho, Hyojung
    • Review of Culture and Economy
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    • v.17 no.2
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    • pp.185-216
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    • 2014
  • It has been two years since the national certificate of Arts & Culture Education Instructor(ACEI) was implemented the 2012 amendment to the Arts & Culture Education Act. Separate from the initial policy goals, students who attend the program to achieve ACEI certificate share various expectations, motivations and intents. The purpose of the research is to understand the collective identity of future ACEIs to evaluate the initial policy implementation during the period when the collective professional identity has not been fully formed yet. This research studies the data that were collected from 172 students who were attending one of the official ACEI institutes in Seoul area. As one of qualitative research methods, Questionnaire Method was employed to conduct this phenomenological study. James E Marcia's theory provides the theoretical framework for the data analysis of this study. The research results indicate that many students'identity status are between Identity Diffusion and Moratorium, which raises concerns for both arts and cultural fields as well as the policy success. Therefore, this research will relate these findings to the larger arts and culture infrastructure in order to better prepare them as arts and cultural professionals and also to stress the importance of the job market development and social environment that can accept them.

Current Status and User Experiences of the Science-Related YouTube Services by Government-Funded Research Institutes (정부출연연구기관의 과학 유튜브 서비스 현황과 이용자 경험 연구)

  • Byun, Kwanjoo;Oh, Sanghee
    • Journal of Korean Library and Information Science Society
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    • v.52 no.4
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    • pp.277-307
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    • 2021
  • This study aims to understand the current status of science-related channels on YouTube provided by government-funded research institutes and investigate user experiences and behaviors of using the services. We examined the number of subscribers, view counts, and video contents of 26 YouTube channels from the government-funded research institutes. We also designed a user study with the uses and gratifications theory and conducted a semi-structured interview. By grouping videos into five categories: Public Relations, Lectures, Entertainment, Vlogs, and Q&A, most videos were about research projects or institutional promotions. User motivation for using the YouTube channel was to acquire scientific knowledge and information. Users thought that YouTube channels could provide reliable information and satisfy their intellectual curiosity. But they criticized that most videos were uninteresting, and the lack of promotions of the channels made others hesitant to sign up and watch. Findings from this study could help fully understand the current status of the government-funded research institute's YouTube channel and be used as resources for the government's planning and development of various YouTube services.