• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.53-55
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• 2004

In emergency cases, such as the severe trauma involving the fracture of skull, spine, or cervical bone, from auto accident or a fall, and/or pneumothorax which can not be diagnosed exactly by the eye examination, it is necessary the radiological examination during transferring to the hospital for emergency care. The aim of this study was to design and evaluate the prototype of mobile medical image communication system based on CDMA 1X EVDO. The system consists of a laptop computer used as a transmit DICOM client, linked with cellular phone which support to the CDMA 1X EVDO communication service, and a receiving DICOM server installed in the hospital. The DR images were stored with DICOM format in the storage of transmit client. Those images were compressed into JPEG2000 format and transmitted from transmit client to the receiving server. All of those images were progressively transmitted to the receiving server and displayed on the server monitor. To evaluate the image quality, PSNR of compressed image was measured. Also, several field tests had been performed using commercial CDMA2000 1X-EVDO reverse link with the TCP/IP data segments. The test had been taken under several velocity of vehicle in seoul areas.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.168-168
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• 2017

ICT 융합 스마트팜 내의 환경계측 센서, 영상 및 사양관리 시스템의 증가에도 불구하고 이들 장비에서 확보되는 데이터를 적절히 유효하게 활용하는 기술이 미흡한 실정이다. 돈사의 경우 가축의 복지수준, 성장 변화를 실시간으로 모니터링 및 예측할 수 있는 데이터 분석 및 모델링 기술 확보가 필요하다. 이를 위해선 가축의 생리적 변화 및 행동적 변화를 조기에 감지하고 가축의 복지수준을 실시간으로 감시하고 분석 및 예측 기술이 필요한데 이를 위한 대표적인 정보 통신 공학적 접근법 중에 하나가 Data mining 이다. Data mining에 대한 연구 수행에 필요한 다양한 소프트웨어 중에서 Open source로 제공이 되는 4가지 도구를 비교 분석하였다. 스마트 돈사 내에서 열환경 모델링을 목표로 한 데이터 분석에서 고려해야할 요인으로 데이터 분석 알고리즘 도출 시간, 시각화 기능, 타 라이브러리와 연계 기능 등을 중점 적으로 분석하였다. 선정된 4가지 분석 도구는 1) R(https://cran.r-project.org), 2) OpenCV(http://opencv.org), 3) OpenNN (http://www.opennn.net), 4) Orange(http://orange.biolab.si) 이다. 비교 분석을 수행한 운영체제는 Linux-Ubuntu 16.04.4 LTS(X64)이며, CPU의 클럭속도는 3.6 Ghz, 메모리는 64 Gb를 설치하였다. 개발언어 측면에서 살펴보면 1) R 스크립트, 2) C/C++, Python, Java, 3) C++, 4) C/C++, Python, Cython을 지원하여 C/C++ 언어와 Python 개발 언어가 상대적으로 유리하였다. 데이터 분석 알고리즘의 경우 소스코드 범위에서 라이브러리를 제공하는 경우 Cross-Platform 개발이 가능하여 여러 운영체제에서 개발한 결과를 별도의 Porting 과정을 거치지 않고 사용할 수 있었다. 빌트인 라이브러리 경우 순서대로 R 의 경우 가장 많은 수의 Data mining 알고리즘을 제공하고 있다. 이는 R 운영 환경 자체가 개방형으로 되어 있어 온라인에서 추가되는 새로운 라이브러리를 클라우드를 통하여 공유하기 때문인 것으로 판단되었다. OpenCV의 경우 영상 처리에 강점이 있었으며, OpenNN은 신경망학습과 관련된 라이브러리를 소스코드 레벨에서 공개한 것이 강점이라 할 수 있다. Orage의 경우 라이브러리 집합을 제공하는 것에 중점을 둔 다른 패키지와 달리 시각화 기능 및 망 구성 등 사용자 인터페이스를 통합하여 운영한 것이 강점이라 할 수 있다. 열환경 모델링에 요구되는 시간 복잡도에 대응하기 위한 부가 정보 처리 기술에 대한 연구를 수행하여 스마트팜 열환경 모델링을 실시간으로 구현할 수 있는 방안 연구를 수행할 것이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1054-1061
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• 2015

Navigation accuracy, integrity, and safety of commercial Unmanned Aerial Vehicle (UAV) is becoming crucial as utilization of UAV in commercial applications is expected to increase. Recently, the concept of Local-Area Differential GNSS (LADGNSS) which can provide navigation accuracy and integrity of UAV was proposed. LADGNSS can provide differential corrections and separation distances for precise and safe operation of the UAV. In order to derive separation distances between UAVs, modeling of Flight Technical Error (FTE) is required. In most cases, FTE for civil aircraft has been assumed to be zero-mean normal distribution. However, this assumption can cause overconservatism especially for UAV, because UAV may use control and navigation equipments in wider performance range and follow more diverse path than standard airway for civil aircraft. In this research, flight experiments were carried out to understand the characteristics of FTE distribution. Also, this paper proposes to use Johnson distribution which can better describe heavy-tailed and skewed FTE data. Futhermore, Kolmogorov-Smirnov and Anderson-Darling tests were conducted to evaluate the goodness of fit of Johnson model.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.83-90
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• 2004

DVB-MHP recommends that NPT(normal play time) be used as the times of stream events. NPT is the local time within an event(TV program). But we found that commercial transport stream (TS) generators and middlewares for DVB-MHP settop boxes are not ready to support the use of NPT by applications. In particular, TS generators do not create NPT reference descriptors needed to reconstruct NPT at the TV receiver. This situation is undesirable because program providers cannot experiment with the idea of synchronized applications. So we have implemented a TS generator that inserts NPT reference descriptors to TS and MyGetNPT API to approximately reconstruct NPT. STC (system time clock) is needed to reconstruct NPT, but Xlets are not allowed to read it. So, we approximate STC by using PCR (program clock reference) and the Java system tune. In this method, the stream generator extrats PCRs from an existing TS and inserts them into null TS packets in the form of MPEG sections, which can be read by Xlets. Because PCRs are displaced into new positions in TS, their values should be adjusted based on the time intervals between the original positions and the new positions. We implemented a synchronized application by using our TS generator and MyGetNPT API, where the task of stream events are to display graphic images. We found that graphic images are displayed where 240 ㎳ from their intended time, where 240ms is a human tolerance for the synchronization skew between graphic image and video.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.369-380
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• 2003

With the proliferation of a wireless support and the advances of mobile devices, there is a growing need of making it available for a wireless network as well. Low bandwidth of a wireless network is one of the major issues that should be considered for extending a synchronous collaboration system developed for a wired network to supuort a wireless network. We propose a priority-based view synchronization scheme, exploiting the relaxed synchronization. The proposed scheme leverages the fact that mobile users need not have the exactly same view as the users in a wired network since they usually have a limited screen size and thus focus only on part of a whole document. We evaluate the performance of a simple group editor with the propose scheme using ns -2. The performance results show that the proposed scheme keeps the message transmission delay low so that mobile users can have synchronous colloboration with wired users without signification delay. The proposed scheme is designed and implemented as a framework to support various kinds of realtime groupware applications, exploiting the existing groupware framework, Habanero. As a client program, we implemented a simple group text editor.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.6
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• pp.752-758
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• 2013

Estrogen like activities were evaluated using ethanol and hot water extracts of herbal medicines by using an in vitro detection system. Bokryung (Poria cocos), Sanyak (root of Dioscorea batatas) and Mokdanpi (root skin of Paeonia suffruticosa) represented statistically significant estrogen-like activities (p<0.001), while Omija (fruit of Schizandra chinensis), Taeksa (root of Alisma canaliculatum A. BR.), Jihwang (root of Rhemannia glutinosa), and Sansuyu (fruit of Cornus officinalis) did not. Estrogen-like activities of Bokryung hot water extract (500 ${\mu}g/ml$) and ethanol extract (50 ${\mu}g/ml$) were almost same as that of a C M $17{\beta}$-estradiol. Furthermore, estrogen-like activities of ethanol extracts (500 ${\mu}g/ml$) of Bokryung and Mokdanpi were stronger than that of $10^{-7}$ M $17{\beta}$-estradiol. These results suggest that Bokryung, Sanyak and Mokdanpi show estrogen-like activities. Especially, Sanyak and Mokdanpi represented promotive effect on the proliferation of MC3T3-E1 osteoblastic cells. Bokryung, Sanyak and Mokdanpi also exhibited superior inhibitory effect on the viability of RAW 264.7 cells. In conclusion, these three herbal medicines might be interpreted as candidates for the further study or development of functional foods or medicine to prevent or avoid postmenopausal symptoms of women.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.93-103
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• 2006

소비자의 하이테크 서비스 가입 이후 행태를 살펴보면, 가입자들은 서비스를 실제로 사용하기도 전에 가입 해지결정을 내리기도 한다. 최근 미국의 기간통신회사에서 출시된 인터넷전화 서비스의 경우, 출시 후 1년 반 동안 이탈한 고객 중 무려 60%정도가 서비스를 실제로 사용하기 전 상태인 네트워크 및 시스템이 준비되는 동안이나 소비자가 가정에서 전화기 연결용 어댑터를 설치하는 단계에서 이탈한 것으로 나타났다. 이와 같은 가입초기 고객의 이탈은 기업에게 고객획득과정에서 지출된 마케팅비용의 손실 및 미래의 매출감소뿐만 아니라, 기 가입자를 통한 미래의 가입 희망자에게 미칠 수 있는 긍정적 구전효과와 같은 간접효과에 대한 손실을 의미한다. 하지만 하이테크 서비스에 대한 소비자의 가입 후 행태에 대한 기존연구는 고객불평 연구, 서비스 사용 후 발생하는 정상적 이탈행태(normal churn)에 대한 연구, 또는 탐색적 연구를 제외하면 매우 부족하다. 더욱이 하이테크서비스의 특성을 고려한 서비스 출시초기에 소비자의 가입직후 해지결정에 대한 결정요인 연구는 그 필요성에 비해 연구가 전무하다시피한 실정이다. 본 연구에서는 하이테크 서비스에 대한 소비자의가입시점과 실제 사용시점 사이에 발생하는 소비자의 이탈행태를 이탈시점에 따라 '가입직후 이탈(immediate churn)' 과 '가입 후 이탈(earlychurn)'로 정의한 후, 특히 가입직후 고객의 이탈행태를 설명하기 위해 하이테크 서비스에 대한 소비자의 이전 사용경험정도와 서비스에 대한 정보를 획득한 채널의 정보전달 풍부성 등을 연구모형에 포함하였다. 이 기간 동안에 기업은 서비스 제공에 필요한 부수적인 기기 제공 및 서비스 준비 등을 수행하지만, 동시에 소비자는 여러가지 이유로 가입결정을 제고할 수도 있게 된다. 제안된 연구모형에 대한 실증분석을 위해 미국 유수의 기간통신회사에서 2004년 출시된 인터넷전화(Voice over Internet Protocol: VoIP)서비스에 가입한 12,000여명 의 고객 프로파일과 서비스사용 데이터를 활용하였다. 분석결과 가입자의 하이테크 서비스에 대한 사용경험정도가 낮을수록 서비스 가입직후 바로 해지하는 경향을 보였다. 하지만 하이테크 서비스에 대한 이전 사용경험이 낮은 경우라도, 가입 후서비스를 실제로 사용하였다면 서비스에 대한 가입해지 경향은 더 이상 나타나지 않았다. 이는 가입자의 하이테크 서비스에 대한 이전 사용경험정도가 가입직후 해지에만 영향을 미치는 요인임을 보여준다. 또한 매체의 정보전달 풍부성 (media richness)이 상대적으로 높은 소매점이나 웹사이트를 통해 서비스에 가입한 소비자일수록 가입 직후뿐만 아니라 서비스사용 이후에도 낮은 해지성향을 나타냈다. 이러한 분석결과를 바탕으로 인터넷전화 서비스에 적합한 고객지원 프로그램 설계와 마케팅 매체선정과 관련한 전략적 시사점을 도출한다. 그리고 국내에서 최근 이슈가 되고 있는 차세대 무선인터넷 서비스인 와이브로 출시에 따른 마케팅 및 고객관리와 관련된 시사점을 논의한다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.196-205
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• 2017

In recent years, the service design in the medical sector evolves through practical service research and development that can visualize both intangible and intangible service elements in an integrative way and derive innovative solutions to help customers feel the service more important value. With the improvement of personal income, interest in medical welfare and well-being is increasing day by day, and the focus of the medical sector shifts from the concept of treatment of diseases and illness to preventive medicine. In response to this trend, research and development of home health care system, which greatly reduces the time and space constraint of health checkup and health care by combining ubiquitous concept with medical welfare, are being actively conducted, and the needs for improving products and medical environment based on user-centered medical service and user needs in accordance with the Health Care 3.0 Era, it becomes necessary to develop on-site medical diagnostic products that reflect user-centered needs and needs. This study is intended to research and develop a product that sufficiently reflects the needs of users by applying suitable materials and shape for on-site diagnostic product in researching and developing Wireless X-ray Detector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.922-929
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• 2005

This paper proposes an adaptive pilot beacon equipment for mobile communication systems based on direct spread spectrum technology which generates the pilot channel for handoff between base stations by using the information acquired from the downstream wireless signal regarding the overhead channel information. Such an adaptive pilot beacon equipment will enable low power operation since among the wireless signals, only the pilot channel will be generated and transmitted. The pilot channel in the downstream link of the CDMA receiver is used to acquire time and frequency synchronization and this is used to calibrate the offset for the beacon, which implies that time synchronization using GPS is not required and any location where forward receive signal can be received can be used as the installation site. The downstream link pilot signal searching within the CDMA receiver is performed by FPGA and DSP. The FPGA is used to perform the initial synchronization for the pilot searcher and DSP is used to perform the offset correction between beacon clock and base station clock. The CDMA transmitter the adaptive pilot beacon equipment will use the timing offset information in the pilot channel acquired from the CDMA receiver and generate the downstream link pilot signal synchronized to the base station. The intermediate frequency signal is passed through the FIR filter and subsequently upconverted and amplified before being radiated through the antenna.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.35-44
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• 2010

For efficient maintenance management of bridges, an establishment of asset management system is necessary which helps prediction of maintenance cost and strategic allocation of budget in consideration of top priority. The main purpose of this study is to suggest asset valuation method, which is practical in conformity with domestic situations, through researches on asset valuation method of bridges. This study has researched asset valuation method of bridge, which is appropriate for domestic situations by finding out advantages and disadvantages through investigating domestic and foreign application examples of asset valuation method for bridge facilities. In this study, asset valuation method by historical cost and replacement cost were suggested and a valuation model for bridges was established. In addition, two suggested valuation methods were applied to actual bridges which is used in Korea. As the result, it was analyzed that bridge asset valuation method in consideration of historical cost is desirable for the accounting purpose. And, it was analyzed that valuation method utilizing depreciated replacement cost(DRC), which could consider various factors, is desirable for the maintenance decision supporting purpose.