• Title/Summary/Keyword: Fixed time technique

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A Study on the Radiation Exposure Dose of Brain Perfusion CT Examination a Phantom (Phantom을 이용한 뇌 관류 CT검사에서 방사선 피폭선량에 관한 연구)

  • Jung, Hong-Rynag;Kim, Ki-Jeong;Mo, Eun-Hee
    • Journal of the Korea Convergence Society
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    • v.6 no.5
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    • pp.287-294
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    • 2015
  • The purpose of this study, was Let's examine the exposure dose at the time of cerebral blood flow CT scan of acute ischemic stroke patients. In particular, long-term high doses of radiation sensitive organs and we Measured using phantom and a glass dosimeter. Apply the existing protocol suggested by the manufacturer (fixed time delay technique) and the proposed new convergence protocol (bolus tracking technique), reporting to measure the dose, dose reduction was to prepare the way. Results up to 39.8% as compared to the existing protocols in a new suggested convergence protocol, a minimum of 5.8% was long-term dose is reduced. Test dose of $CDTI_{vol}$ and DLP values decreased 25%, respectively, were measured at less than recommended dose. Try checking the protocol set out in the existing based on the analysis result of the above, by applying the proposed new convergence protocol by reducing the dose would have to contribute to improved public health. It is believed to be research continues to find the optimum protocol in the other tests.

The real-time scheduling algorithms based on the Insertion technique and Two-way SCAN technique (삽입기법과 양방향 스캔 기법에 기반한 실시간 디스크 스케줄링 알고리즘)

  • Lee Myung Sub;Park Chang Hyeon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6B
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    • pp.377-386
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    • 2005
  • Recently, to increase throughput per hour on real-time disk scheduling, a lot of algorithms that apply SCAN technique to EDF(Earliest Deadline First) that is representative real-time disk scheduling algorithm are studied. However, existing disk scheduling algorithms have several limitations because they consider continuous I/O requests when create SCAN group. Also, because SCAN technique was fixed direction, the existing algorithms have shortcoming that there are a lot of time damages. This paper proposes a new real-time disk scheduling algorithm based on the insertion technique and the two-way SCAN technique to solve the problems of the exiting real-time disk scheduling algorithms in hard real-time system. The simulation result shows that, when using our techniques, the disk throughput and the number of serviceable I/O requests are enhanced.

Real-Time Generation of City Map for Games in Unity with View-dependent Refinement and Pattern Synthesis Algorithm

  • Kim, Jong-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.4
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    • pp.51-56
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    • 2019
  • In this paper, we propose an algorithm that can quickly generate and synthesize city maps in racing games. Racing games are characterized by moving a wide map rather than a fixed map, but designing and developing a wide map requires a lot of production time. This problem can be mitigated by creating a large map in the preprocessing step, but a fixed map makes the game tedious. It is also inefficient to process all the various maps in the preprocessing step. In order to solve this problem, we propose a technique to create a terrain pattern in the preprocessing process, to generate a map in real time, and to synthesize various maps randomly. In addition, we reduced unnecessary rendering computations by integrating view-dependent techniques into the proposed framework. This study was developed in Unity3D and can be used for various contents as well as racing game.

An Adaptive Undervoltage Load Shedding Against Voltage Collapse Based Power Transfer Stability Index

  • Nizam, Muhammad;Mohamed, Azah;Hussain, Aini
    • Journal of Electrical Engineering and Technology
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    • v.2 no.4
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    • pp.420-427
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    • 2007
  • This paper highlights the comparison of a proposed methods named adaptive undervoltage load shedding based PTSI techniques for undervoltage load shedding and two previous methods named Fixed Shed Fixed Delay (FSFD) and Variable Shed Variable Delay (VSVD) for avoiding voltage collapse. There are three main area considerations in load shedding schemes as the amount of load to be shed, the timing of load shedding event, and the location where load shed is to be shed. The proposed method, named as adaptive UVLS based PTSI seem to be most appropriate among the uncoordinated schemes. From the simulation result can be shown the Adaptive UVLS based PTSI give faster response, accurate and very sensitive control for the UVLS control technique. This technique is effectively when calculating the amount to be shed. Therefore, it is possible to bring the voltage to the threshold value in one step. Thus, the adaptive load shedding can effectively reduce the computational time for control strategy.

Occlusal Adjustment in the Natural and Restored Dentition (고정성 보철물 및 자연치열을 위한 교합조정)

  • Ahn, Seung-Geun
    • Journal of Dental Rehabilitation and Applied Science
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    • v.19 no.1
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    • pp.49-55
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    • 2003
  • When treating the occlusion the dentist must ensure that patients do not develop an occlusal awareness or neurosis after therapy. This means that after treatment patients should not be conscious of the dentition at rest, in occlusion, or during function. Butactually this goal is not easy to reach in daily practice. The dental technician works with rigid casts and dies that do not move. The dentist must use fixed prostheses that have been made in a laboratory setting in a clinical environment that is significantly different. In this article relativey easy cast adjustment technique which can decrease the time necessary to clinically adjust the occlusion of newly fabricated fixed prostheses, and actual occlusal equilibration technique for natural and restored dentition will be discussed.

Design and Implementation of Flexible Sensor to Measure Mechanical Stiffness of Soft Particles (Soft Particle의 강성 측정을 위한 단순한 구조의 유연 물질 센서의 개발)

  • Ihn, Yong Seok;Yang, Minho;Koo, Ja Choon
    • The Journal of Korea Robotics Society
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    • v.11 no.3
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    • pp.133-139
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    • 2016
  • Increasing interest of human health, building bio-database (Bio DB) has been become a hot issue in life science. Consequently, Single Cell Analysis (SCA) which can explain biodiversity of lives has been a significant factor for building Bio DB. In numerous studies from these analyses, they have been showed that mechanical properties of cells can serve explanation of biological heterogeneity and criterion of disease states. Therefore, measuring mechanical properties of cells have great potential to be used in bio-medical applications. However, traditionally, many researchers have undergone difficult and time consuming work because handling small sized cells usually requires high-skilled technique. Thus, this paper shows robotized stiffness measurement technique using fixed ended beam sensor, precision motorized stage and substrate which have wall structure.

Experimental Studies of Neural Compensation Technique for a Fuzzy Controlled Inverted Pendulum System

  • Lee, Geun-Hyeong;Jung, Seul
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.10 no.1
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    • pp.43-48
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    • 2010
  • This article presents the experimental studies of controlling angle and position of the inverted pendulum system using neural network to compensate for errors caused due to fuzzy controller. Although fuzzy control method can deal with nonlinearities of the system, fixed fuzzy rules may not work and result in tracking errors in some cases. First, a nominal Takagi-Sugeno (TS) type fuzzy controller with fixed weights is used for controlling the inverted pendulum system. Then the neural network is added at the reference input to form the reference compensation technique (RCT)control structure. Neural network modifies the input trajectories to improve system performances by updating internal weights in on-line fashion. The back-propagation learning algorithm for neural network is derived and used to update weights. Control hardware of a DSP 6713 board to have real time control is implemented. Experimental results of controlling inverted pendulum system are conducted and performances are compared.

System Technique of Light Rail Transit (경량 전철 시스템 기술)

  • Yu, Hae-Chul;Lee, Jae-Seok
    • Journal of the Korean Professional Engineers Association
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    • v.40 no.6
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    • pp.59-64
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    • 2007
  • LRT(LAght Rail Transit) system is a new transportation system with new technique of an electric railway. Transportation ability of LRT is mid-scale of a bus and a subway, transporting 5,000-30,000 people per hour and direction. LRT automatically operates in the existing metropolitan railway and large-scale development areas or satellite cities with a fixed route and has a short interval that guarantees scheduled-time, safety and environment-friendly.

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Sliding Mode Controller Design Considering Weight (가중치를 고려한 슬라이딩 모드 제어기 설계)

  • 임동균;서병설
    • Proceedings of the KIPE Conference
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    • 1998.11a
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    • pp.73-77
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    • 1998
  • The conventional sliding mode controller (SMCr) approach is often impractical or difficult when applied to high order process because the number of tuning parameters in the SMCr increases with the order of the plant. Camacho(1996) proposed the design of a fixed structure sliding mode controller based on a first order plus dead time approximation to the higher-order process. But, there are such problems as overshoot, settling time and command following. They are mainly due to the approximation errors of the time delay term by Taylor series. In this paper, in order to improve Camcho's method, a new Taylor approximation technique considering a weight is proposed.

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Reducing of Craniofacial Radiation Dose Using Automatic Exposure Control Technique in the 64 Multi-Detector Computed Tomography (64 다중 검출기 전산화단층촬영에서 관전류 자동노출조절 기법을 이용한 두개부 방사선량 감소 정도 평가)

  • Seoung, Youl-Hun;Kim, Yong-Ok;Choe, Bo-Young
    • Progress in Medical Physics
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    • v.21 no.2
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    • pp.137-144
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    • 2010
  • The purpose of this study was to evaluate the usefulness of reducing of craniofacial radiation dose using automatic exposure control (AEC) technique in the 64 multi-detector computed tomography (MDCT). We used SOMATOM Definition 64 multi-detector CT, and head of whole body phantom (KUPBU-50, Kyoto Kagaku CO. Ltd). The protocol were helical scan method with 120 kVp, 1 sec of rotation time, 5 mm of slice thickness and increment, 250 mm of FOV, $512{\times}512$ of matrix size, $64{\times}0.625\;mm$ of collimation, and 1 of pitch. The evaluation of dose reducing effect was compared the fixed tube current of 350 with AEC technique. The image quality was measured the noise using standard deviation of CT number. The range of craniofacial bone was to mentum end from calvaria apex, which devided three regions: calvaria~superciliary ridge (1 segment), superciliary ridge~acanthion (2 segment), and acanthion~mentum (3 segment). In the fixed tube current technique, CTDIvol was 57.7 mGy, DLP was $640.2\;mGy{\cdot}cm$ in the all regions. The AEC technique was showed that 1 segment were 30.7 mGy of CTDIvol, 340.7 $mGy{\cdot}cm$ of DLP, 2 segment were 46.5 mGy of CTDIvol, $515.0\;mGy{\cdot}cm$ of DLP, and 3 segment were 30.3 mGy of CTDIvol, $337.0\;mGy{\cdot}cm$ of DLP. The standard deviation of CT number was 2.622 with the fixed tube current technique and 3.023 with the AEC technique in the 1 segment, was 3.118 with the fixed tube current technique and 3.379 with the AEC technique in the 2 segment, was 2.670 with the fixed tube current technique and 3.186 with the AEC technique in the 3 segment. The craniofacial radiation dose using AEC Technique in the 64 MDCT was evaluated the usefulness of reducing for the eye, the parotid and thyroid with high radiation sensitivity particularly.