• Title/Summary/Keyword: Simulation-based Acquisition

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Evaluation of Scatter Reduction Effect of the Aft-Multiple-Slit (AMS) System Using MC Simulation (MC 시뮬레이션을 이용한 Aft-Multiple-Silt 시스템의 산란선 제거 효과 평가)

  • Chang, Jin-A;Suh, Tae-Suk;Jang, Doh-Yun;Jang, Hong-Seok;Kim, Si-Yong
    • Radiation Oncology Journal
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    • v.28 no.4
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    • pp.224-230
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    • 2010
  • Purpose: We designed the aft-multiple-slit (AMS) system to reduce scatter in cone-beam computed tomography (CBCT). As a preliminary study, we performed a Monte Carlo N-Particle Transport Code (MCNP) simulation to verify the effectiveness of this system. Materials and Methods: The MCNPX code was used to build the AMS geometry. An AMS is an equi-angled arc to consider beam divergence. The scatter-reduced projection images were compared with the primary images only and the primary plus scatter radiation images with and without AMS to evaluate the effectiveness of scatter reduction. To obtain the full 2 dimensional (2D) projection image, the whole AMS system was moved to obtain closed septa of the AMS after the first image acquisition. Results: The primary radiation with and without AMS is identical to all the slit widths, but the profiles of the primary plus scattered radiation varied according to the slit widths in the 2D projection image. The average scatter reduction factors were 29%, 15%, 9%, and 8% when the slit widths were 5 mm, 10 mm, 15 mm, and 20 mm, respectively. Conclusion: We have evaluated the scatter reduction effect of the AMS in CBCT imaging using the Monte Carlo (MC) simulations. A preliminary study based on the MCNP simulations showed a mount of scatter reduction with the proposed system.

A Study on Converting the Data of Probability of Hit(Ph) for OneSAF Model (OneSAF 모델을 위한 명중률 데이터 변환 방법)

  • Kim, Gun In;Kang, Tae Ho;Seo, Woo Duck;Pyun, Jae Jung
    • Journal of the Korea Society for Simulation
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    • v.29 no.3
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    • pp.83-91
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    • 2020
  • To use the OneSAF model for the analysis of Defence M&S, the most critical factor is the acquisition of input data. The model user is hard to determine the input data such as the probability of hit(Ph) and the probability of kill(Pk). These data can be obtained directly by live fire during the development test and the operational test. Therefore, this needs more time and resources to get the Ph and Pk. In this paper, we reviewed possible ways to obtain the Ph and Pk. We introduced several data producing methodologies. In particular, the error budget method was presented to convert the Ph(%) data of AWAM model to the error(mil) data of OneSAF model. Also, the conversion method which can get the adjusted results from the JMEM is introduced. The probability of a hit was calculated based on the error budget method in order to prove the usefulness of the given method. More accurate data were obtained when the error budget method and the projected area from the published photo were used simultaneously. The importance of the Ph calculation was demonstrated by sensitivity analysis of the Ph on combat effectiveness. This paper emphasizes the importance of determining the Ph data and improving the reliability of the M&S system though steady collection and analysis of the Ph data.

Analysis of Educational Elements of Educational Online Games - Focused on Real Farm Games - (교육용 온라인 게임의 교육적 요소 분석 - 레알팜 게임을 중심으로 -)

  • Jung, Mi-A;Jung, Hyung-Won
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.3
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    • pp.173-180
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    • 2020
  • According to KISA, many people play smartphone games. stress relieving, time is the reason to beat. Attempts to combine mobile games and education in the Korean game market are continuing. Studies have shown that using commercial games for education can be effective. Also, researches for activation educational games are increasing. Creating educational games requires a lot of time and money. Due to the nature of mobile games, the service is often terminated without updating. If you are able to acquire a naturally educational part while playing mobile games, you will see the effect of one pair of fun and education, both at once. We analyzed the education factors of the game with 'Real Farm' which is a simulation farm game. We focused on analyzing information acquisition and utilization part through indirect experience which is characteristic of simulation and examined educational factors based on design elements of educational game. This can signal the positive aspects of the game and the educational content of existing games. If you use smartphones as a pedagogy, you can expect a positive perception of games and an increase in the average life expectancy of mobile games.

Deep Learning Applied Method for Acquisition of Digital Position Signal of PET Detector (PET 검출기의 디지털 위치 신호 측정을 위한 딥러닝 적용 방법)

  • Byungdu, Jo;Seung-Jae, Lee
    • Journal of the Korean Society of Radiology
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    • v.16 no.6
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    • pp.697-702
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    • 2022
  • For imaging in positron emission tomography(PET), it is necessary to measure the position of the scintillation pixel interacting with the gamma rays incident on the detector. To this end, in the conventional system, a flood image of the scintillation pixel is obtained, the imaged area of each scintillation pixel is separated, and the position of the scintillation pixel is specified and acquired as a digital signal. In this study, a deep learning method was applied based on the signal formed by the photosensor of the detector, and a method was developed to directly acquire a digital signal without going through various procedures. DETECT2000 simulation was performed to verify this and evaluate the accuracy of position measurement. A detector was constructed using a 6 × 6 scintillation pixel array and a 4 × 4 photosensor, and a gamma ray event was generated at the center of the scintillation pixel and summed into four channels of signals through the Anger equation. After training the deep learning model using the acquired signal, the positions of gamma-ray events that occurred in different depth directions of the scintillation pixel were measured. The results showed accurate results at every scintillation pixel and position. When the method developed in this study is applied to the PET detector, it will be possible to measure the position of the scintillation pixel with a digital signal more conveniently.

RFID Based Mobile Robot Docking Using Estimated DOA (방향 측정 RFID를 이용한 로봇 이동 시스템)

  • Kim, Myungsik;Kim, Kwangsoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.9
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    • pp.802-810
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    • 2012
  • This paper describes RFID(Radio Frequency Identification) based target acquisition and docking system. RFID is non-contact identification system, which can send relatively large amount of information using RF signal. Robot employing RFID reader can identify neighboring tag attached objects without any other sensing or supporting systems such as vision sensor. However, the current RFID does not provide spatial information of the identified object, the target docking problem remains in order to execute a task in a real environment. For the problem, the direction sensing RFID reader is developed using a dual-directional antenna. The dual-directional antenna is an antenna set, which is composed of perpendicularly positioned two identical directional antennas. By comparing the received signal strength in each antenna, the robot can know the DOA (Direction of Arrival) of transmitted RF signal. In practice, the DOA estimation poses a significant technical challenge, since the RF signal is easily distorted by the surrounded environmental conditions. Therefore, the robot loses its way to the target in an electromagnetically disturbed environment. For the problem, the g-filter based error correction algorithm is developed in this paper. The algorithm reduces the error using the difference of variances between current estimated and the previously filtered directions. The simulation and experiment results clearly demonstrate that the robot equipped with the developed system can successfully dock to a target tag in obstacles-cluttered environment.

Image Restoration and Segmentation for PAN-sharpened High Multispectral Imagery (PAN-SHARPENED 고해상도 다중 분광 자료의 영상 복원과 분할)

  • Lee, Sanghoon
    • Korean Journal of Remote Sensing
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    • v.33 no.6_1
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    • pp.1003-1017
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    • 2017
  • Multispectral image data of high spatial resolution is required to obtain correct information on the ground surface. The multispectral image data has lower resolution compared to panchromatic data. PAN-sharpening fusion technique produces the multispectral data with higher resolution of panchromatic image. Recently the object-based approach is more applied to the high spatial resolution data than the conventional pixel-based one. For the object-based image analysis, it is necessary to perform image segmentation that produces the objects of pixel group. Image segmentation can be effectively achieved by the process merging step-by-step two neighboring regions in RAG (Regional Adjacency Graph). In the satellite remote sensing, the operational environment of the satellite sensor causes image degradation during the image acquisition. This degradation increases variation of pixel values in same area, and results in deteriorating the accuracy of image segmentation. An iterative approach that reduces the difference of pixel values in two neighboring pixels of same area is employed to alleviate variation of pixel values in same area. The size of segmented regions is associated with the quality of image segmentation and is decided by a stopping rue in the merging process. In this study, the image restoration and segmentation was quantitatively evaluated using simulation data and was also applied to the three PAN-sharpened multispectral images of high resolution: Dubaisat-2 data of 1m panchromatic resolution from LA, USA and KOMPSAT3 data of 0.7m panchromatic resolution from Daejeon and Chungcheongnam-do in the Korean peninsula. The experimental results imply that the proposed method can improve analytical accuracy in the application of remote sensing high resolution PAN-sharpened multispectral imagery.

Development of Real-Time Forecasting System of Marine Environmental Information for Ship Routing (항해지원을 위한 해양환경정보 실시간 예보시스템 개발)

  • Hong Keyyong;Shin Seung-Ho;Song Museok
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.8 no.1
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    • pp.46-52
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    • 2005
  • A marine environmental information system (MEIS) useful for optimal route planning of ships running in the ocean was developed. Utilizing the simulated marine environmental data produced by the European Center for Medium-Range Weather Forecasts based on global environmental data observed by satellites, the real-time forecast and long-term statistics of marine environments around planned and probable ship routes are provided. The MEIS consists of a land-based data acquisition and analysis system(MEIS-Center) and a onboard information display system(MEIS-Ship) for graphic description of marine information and optimal route planning of ships. Also, it uses of satellite communication system for data transfer. The marine environmental components of winds, waves, air pressures and storms are provided, in which winds are described by speed and direction and waves are expressed in terms of height, direction and period for both of wind waves and swells. The real-time information is characterized by 0.5° resolution, 10 day forecast in 6 hour interval and daily update. The statistic information of monthly average and maximum value expected for a return period is featured by 1.5° resolution and based on 15 year database. The MEIS-Ship include an editing tool for route simulation and the forecasting and statistic information on planned routes can be displayed in graph or table. The MEIS enables for navigators to design an optimal navigational route that minimizes probable risk and operational cost.

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Study on Local Path Control Method based on Beam Modeling of Obstacle Avoidance Sonar (장애물회피소나 빔 모델링 기반의 국부경로제어 기법 연구)

  • Kim, Hyun-Sik
    • Journal of the Korean Institute of Intelligent Systems
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    • v.22 no.2
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    • pp.218-224
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    • 2012
  • Recently, as the needs of developing the micro autonomous underwater vehicle (AUV) are increasing, the acquisition of the elementary technology is urgent. While they mostly utilizes information of the forward looking sonar (FLS) in conventional studies of the local path control as an elementary technology, it is desirable to use the obstacle avoidance sonar (OAS) because the size of the FLS is not suitable for the micro AUV. In brief, the local path control system based on the OAS for the micro AUV operates with the following problems: the OAS offers low bearing resolution and local range information, it requires the system that has reduced power consumption to extend the mission execution time, and it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent local path control algorithm based on the beam modeling of OAS with the evolution strategy (ES) and the fuzzy logic controller (FLC), is proposed. To verify the performance and analyze the characteristic of the proposed algorithm, the course control of the underwater flight vehicle (UFV) is performed in the horizontal plane. Simulation results show that the feasibility of real application and the necessity of additional work in the proposed algorithm.

A Study on 3D Model Building of Drones-Based Urban Digital Twin (드론기반 도심지 디지털트윈 3차원 모형 구축에 관한 연구)

  • Lim, Seong-Ha;Choi, Kyu-Myeong;Cho, Gi-Sung
    • Journal of Cadastre & Land InformatiX
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    • v.50 no.1
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    • pp.163-180
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    • 2020
  • In this study, to build a spatial information infrastructure, which is a component of a smart city, a 3D digital twin model in the downtown area was built based on the latest spatial information acquisition technology, the drone. Several analysis models were implemented by utilizing. While the data processing time and quality of the three types of drone photogrammetry software are different, the accuracy of the construction model is ± 0.04 in the N direction and ± 0.03m in the E direction. In the m and Z directions, ± 0.02m was found to be less than 0.1m, which is defined as the allowable range of surveying performance and inspection performance for the boundary point in the area where the registration of the boundary point registration is executed. 1: 500 to 1 of the aerial survey work regulation: The standard deviation, which is the error limit of the photographic reference point of the 600 scale, appeared within 0.14 cm, and it was found that the error limit of the large scale specified in the cadastral and aerial survey was satisfied. In addition, in order to increase the usability of smart city realization using a drone-based 3D urban digital twin model, the model built in this study was used to implement Prospect right analysis, landscape analysis, Right of light analysis, patrol route analysis, and fire suppression simulation training. Compared to the existing aerial photographic survey method, it was judged that the accuracy of the naked eye reading point is more accurate (about 10cm) than the existing aerial photographic survey, and it is possible to reduce the construction cost compared to the existing aerial photographic survey at a construction area of about 30㎢ or less.

Construction and Experiment of an Educational Radar System (교육용 레이다 시스템의 제작 및 실험)

  • Ji, Younghun;Lee, Hoonyol
    • Korean Journal of Remote Sensing
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    • v.30 no.2
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    • pp.293-302
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    • 2014
  • Radar systems are used in remote sensing mainly as space-borne, airborne and ground-based Synthetic Aperture Radar (SAR), scatterometer and Doppler radar. Those systems are composed of expensive equipments and require expertise and professional skills for operation. Because of the limitation in getting experiences of the radar and SAR systems and its operations in ordinary universities and institutions, it is difficult to learn and exercise essential principles of radar hardware which are essential to understand and develop new application fields. To overcome those difficulties, in this paper, we present the construction and experiment of a low-cost educational radar system based on the blueprints of the MIT Cantenna system. The radar system was operated in three modes. Firstly, the velocity of moving cars was measured in Doppler radar mode. Secondly, the range of two moving targets were measured in radar mode with range resolution. Lastly, 2D images were constructed in GB-SAR mode to enhance the azimuth resolution. Additionally, we simulated the SAR raw data to compare Deramp-FFT and ${\omega}-k$ algorithms and to analyze the effect of antenna positional error for SAR focusing. We expect the system can be further developed into a light-weight SAR system onboard a unmanned aerial vehicle by improving the system with higher sampling frequency, I/Q acquisition, and more stable circuit design.