• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.26-33
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• 2011

In this study, a high-sensitive smart wireless sensor based on an Imote2 sensor platform is developed for structural health monitoring of harbor structures. To achieve the objective, the following approaches are implemented. Firstly, the smart wireless sensor based on the high-performance Imote2 sensor platform is designed to measure acceleration with high sensitivity from structures. Secondly, embedded software is designed for autonomous structural health monitoring. Finally, the performance of the smart wireless sensor is estimated from experimental tests on a lab-scaled caisson structure.

• Air Cleaning Technology
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• v.26 no.3
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• pp.16-24
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• 2013

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.307-310
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• 2011

본 연구에서는 항만 구조물의 구조건전성 모니터링을 위한 Imote2 센서 플랫폼 기반의 스마트 무선센서의 적용성을 평가하였다. 이를 위해 먼저, 고민감도 MEMS 가속도계를 탑재한 Imote2 센서 플랫폼 기반스마트 무선센서를 설계하였다. 둘째, 스마트 무선센서노드의 독자적인 구조 상태 모니터링을 위한 내장소프트웨어를 설계하였다. 마지막으로, 모형 케이슨 구조물의 진동실험을 통해 개발된 스마트 무선센서의 성능을 검증하였다.

• The Korean Journal of Nuclear Medicine
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• v.35 no.2
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• pp.100-112
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• 2001

Purpose: The purpose of this study was to establish optimal imaging acquisition conditions for the GE $Advance^{TM}$ PET imaging system by performing the acceptance tests designed by National Electrical Manufacturers Association (NEMA) protocol and General Electric Medical Systems (GEMS) test procedures. Materials and Methods: Performance tests were carried out with $^{18}FDG$ radioactivity source and phantoms by using a standard acquisition mode. Transaxial resolution and scatter traction tests were performed with a line source and axial resolution with a point source, respectively. A cylindrical phantom made of polymethylmethacrylate (PMMA) was used to measure sensitivity, count rate losses and randoms, uniformity correction, and attenuation inserts were added to measure remaining tests. The test results were acquired in a diagnostic acquisition mode and analyzed mainly on high sensitivity mode. Results: Transaxial resolution and axial resolution were measured as average of 4.65 mm and 3.98 mm at 0 cm, and 6.02 mm and 6.71 mm at 20 cm on high sensitivity mode, respectively. Average scatter fraction was 9.87%, and sensitivity was $225.8kcps/{\mu}Ci/cc$ of trues. Activity at 50% deadtime was $4.6{\mu}Ci/cc$, and the error of count rate correction at that activity was from 1.49% to 3.83%. Average nonuniformity for total slice w3s 8.37%. The accuracy of scatter correction was -0.95%. The accuracies of attenuation correction were 5.68% for air, 0.04% for water and -6.51% for polytetrafluoroethylene (PTFE). Conclusion: The results satisfied most acceptance criteria, indicating that the GE $Advance^{TM}$ PET system can be optimally used for clinical applications.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.31-36
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• 2010

Low energy high resolution (LEHR) collimator is the most widely used collimator in SPECT imaging. LEHR has an advantage in terms of image resolution but has a difficulty in acquiring high sensitivity due to the narrow hole size and long septa height. Throughput in SPECT can be improved by increasing counts per second with the use of high sensitivity collimators. The purpose of this study is to develop a system model in iterative image reconstruction to recover the resolution degradation caused by high sensitivity collimators with bigger hole size. We used fan-beam model instead of parallel-beam model for calculation of detection probabilities to accurately model the high sensitivity collimator with wider holes. In addition the weight factors were calculated and applied onto the probabilities as a function of incident angle of incoming photons and distance from source to the collimator surface. The proposed system model resulted in the equivalent performance with the same counts (i.e. in shortened acquisition time) and improved image quality in the same acquisition time. The proposed method can be effectively applied for resolution improvement of pixel collimator of next generation solid state detectors.

• Agrochemical news magazine
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• v.18 no.4 s.139
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• pp.54-56
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• 1997

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.191-196
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• 2012

A double-scattering type Compton camera which is appropriate to imaging a high-energy gamma source has been developed for nuclear material surveillance at Hanyang University. The double-scattering type Compton camera can provide high imaging resolution; however, it has disadvantage of relatively low imaging sensitivity than existing single-scattering type Compton camera. In this study, we introduce a novel concept of a dual-mode Compton camera which incorporates two different types of Compton camera, i.e., single- and double-scattering type. The dual-mode Compton camera can operate high-resolution mode and high-sensitivity mode in a single system. To maximize its performance, the geometrical configuration was optimized by using Geant4 Monte Carlo simulation toolkit. In terms of imaging sensitivity, high-sensitivity mode had higher sensitivity than high-resolution mode up to 100 times while high imaging resolution of the double-scattering Compton camera was maintained.

• Journal of the KSME
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• v.50 no.12
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• pp.50-55
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• 2010

영화 로보캅, 아이언맨 등에 등장하는 외골격기구(exoskeleton)는 이제 더 이상 먼 미래의 얘기도 아니고 딴 나라 얘기도 아니다. 외골격기구 중 특히 하지외골격기구는 Baytheon Sarcos, Berkley Bionics, Exohiker, Bleex, HAL5 등의 이름으로 버클리, 스탠퍼드 등 해외 우수 연구집단에서 이미 개발을 성공하였고 상용화를 앞두고 있다. 늦은 감은 있지만 국내에서도 재활의료용, 군수용 하지외골격기구 연구가 진행되고 있다. 본 저자는 최근 기존연구와 다른 접근방식으로 고민을 시작하였고 본 연구팀이 상표출원한 $PLE^{TM}$, $LeSATA^{TM}$의 개발을 서두르고 있다. 이 글을 통해 그간의 고민들을 간략히 털어놓을까 한다.

• Progress in Medical Physics
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• v.26 no.1
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• pp.18-27
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• 2015

Since a Compton camera has high detection sensitivity due to electronic collimation and a good energy resolution, it is a potential imaging system for nuclear medicine. In this study, we investigated the feasibility of a Compton camera for multi-tracer imaging and proposed a rotating Compton camera to satisfy Orlov's condition for 3D imaging. Two software phantoms of 140 and 511 keV radiation sources were used for Monte-Carlo simulation and then the simulation data were reconstructed by listmode ordered subset expectation maximization to evaluate the capability of multi-tracer imaging in a Compton camera. And the Compton camera rotating around the object was proposed and tested with different rotation angle steps for improving the limited coverage of the fixed conventional Compton camera over the field-of-view in terms of histogram of angles in spherical coordinates. The simulation data showed the separate 140 and 511 keV images from simultaneous multi-tracer detection in both 2D and 3D imaging and the number of valid projection lines on the conical surfaces was inversely proportional to the decrease of rotation angle. Considering computation load and proper number of projection lines on the conical surface, the rotation angle of 30 degree was sufficient for 3D imaging of the Compton camera in terms of 26 min of computation time and 5 million of detected event number and the increased detection time can be solved with multiple Compton camera system. The Compton camera proposed in this study can be effective system for multi-tracer imaging and is a potential system for development of various disease diagnosis and therapy approaches.

• Proceedings of The KACE
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• 2018.01a
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• pp.169-172
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• 2018

본 연구는 SW교육 기초연수를 수강하는 SW교육 초급교사의 SW교육 교수효능감을 측정하고, 그 현황을 파악하여 이를 바탕으로 수강자의 SW교육 교수효능감을 신장시킬 수 있는 연수를 기획 및 수행하는 기초자료를 마련하고자 수행되었다. 연구 결과 SW교육 기초연수에 참가한 교사의 SW교육 교수효능감 중에서 교사 자신의 교수능력에 대한 개인적 판단인 개인효능 영역에서 연령, SW교육 경험에 따라 큰 차이가 존재함을 확인할 수 있었다. 따라서 SW교육 기초연수에서 5년 미만의 저경력 또는 20년 이상의 고경력 교사와 SW교육 경험이 전혀 없는 교사의 개인효능을 향상할 수 있는 방법을 고민하고 이를 연수에 반영할 필요가 있다는 시사점을 도출하였다.