• Title/Summary/Keyword: Engineering M&S

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Hardware-Saving Realizations of Interpolators and Decimators Using Periodically Time-Varying Coefficients

  • Ratansanya, San;Amornraksa, Thumrongrat;Tipakorn, Bundit
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.860-863
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    • 2002

  • Realizations of multirate converters are proposed using periodically time-varying (PTV) structures. By exploiting the computational redundancy of the filtering operation in a multirate filter, it is possible to implement the filter with much less hardware. In the proposed implementations, several coefficients time-share in a periodic fashion the hardware of one multiply-and-add. Therefore, each multiply-and-add circuit performs different coefficient scalings at different time instants within a period. Compared to the direct form realization, the proposed realizations reduce the hardware of an interpolator and a decimator by a factor of approximately U and M, respectively, while retaining the same processing speed, where U and M are the upsampling and downsampling factors, respectively. The approach can be used to obtain realizations for sampling rate conversion by a rational factor of U/M, where U and M are relatively prime, in which case hardware reduction by a factor of approximately UM can be achieved.

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Analysis of Helical Turbine Characteristics for Tidal Current Power Plant (조류발전용 헬리컬 터빈의 특성치 분석)

  • Han, Sang-Hun;Lee, Kwang-Soo;Yum, Ki-Dae;Park, Woo-Sun;Park, Jin-Soon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.4
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    • pp.301-307
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    • 2009

  • The Korean peninsula has a number of coastal sites where the rhythmic rising and lowering of water surface due to tides results in strong tidal current. The kinetic energy of these currents can be efficiently exploited by use of tidal current turbines. This paper investigates the characteristics of helical turbine based on in-field test. The experimental frame was constructed at the Uldolmok narrow channel between Jindo and Haenam and installed the helical turbine of diameter 2.2 m and height 2.5 m. 3-blade turbine had the maximum efficiencies of about 30% in the current velocity range between 1.5 and 2.3 m/s and 6-blade turbine han the maximum efficiencies of about 25%. The efficiency was constant with the current velocity. TSRs of 3-blade and 6 blade turbines were observed as 2.4 and 1.9 respectively.

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Implementation of 3-D Collision Avoidance Algorithm and Comparison of Micro Controller Unit's Performance using Real-Time Operating System (항공기 3차원 충돌회피 알고리즘 구현과 실시간 운영체계를 이용한 Micro Controller Unit의 성능 비교)

  • Lim, Ji-Sung;Kim, Dong-Sin;Park, In-Hyeok;Lee, Sangchul
    • Journal of Aerospace System Engineering
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    • v.12 no.5
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    • pp.48-53
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    • 2018

  • In this study, Real-Time Operating System(RTOS) and 3-D collision avoidance algorithm are implemented to three different Miciro Controller Unit(MCU)s and their performances compared. We selected Microchip Technology's ATmega2560, STM's ARM Cortex-M3 and ARM Cortex-M4, because they are widely used. FreeRTOS, an open-source operating system, was also used. The 3D collision avoidance algorithm consists of the vertical and the horizontal avoidance algorithm, which is implemented using C++. The performances of the MCUs were compared with respect to used memory and calculation time. As a result, Cortex-M4's calculation time was the fastest and ATmega2560 used least memory.

  • https://doi.org/10.20910/JASE.2018.12.5.48 인용 PDF KSCI