• Title/Summary/Keyword: Timer accuracy

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Overhead Compensation Technique to Enhance the Accuracy of a Software Timer for Light-weight Embedded Device (경량 임베디드 디바이스 환경에서 소프트웨어 타이머의 정확성 향상을 위한 오버헤드 보정기법)

  • Kim, Hiecheol
    • Journal of Korea Society of Industrial Information Systems
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    • v.24 no.4
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    • pp.9-19
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    • 2019
  • As light-weight embedded devices become widely used in the area of low-power networking and high-precision sensor data acquisition, support for time-critical applications becomes essential for the light-weight embedded devices. This paper addresses the accuracy issue of a software timer for small or tiny embedded devices equiped with light-weight MCUs(Micro controller units). We first explore the characteristics of overhead in a typical implementation of a software timer, and then measure the overhead through a realistic implementation. Using the measurement result, we propose an overhead compensation technique which reduces the overhead from the hardware timer-tick.

PRICING OF TIMER DIGITAL POWER OPTIONS BASED ON STOCHSTIC VOLATILITY

  • Mijin Ha;Sangmin Park;Donghyun Kim;Ji-Hun Yoon
    • East Asian mathematical journal
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    • v.40 no.1
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    • pp.63-74
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    • 2024
  • Timer options are financial instruments proposed by Société Générale Corporate and Investment Banking in 2007. Unlike vanilla options, where the expiry date is fixed, the expiry date of timer options is determined by the investor's choice, which is in linked to a variance budget. In this study, we derive a pricing formula for hybrid options that combine timer options, digital options, and power options, considering an environment where volatility of an underlying asset follows a fast-mean-reverting process. Additionally, we aim to validate the pricing accuracy of these analytical formulas by comparing them with the results obtained from Monte Carlo simulations. Finally, we conduct numerical studies on these options to analyze the impact of stochastic volatility on option's price with respect to various model parameters.

Long-Tail Watchdog Timer for High Availability on STM32F4-Based Real-Time Embedded Systems (STM32F4 기반의 실시간 임베디드 시스템의 가동시간 향상을 위한 긴 꼬리 와치독 타이머 기법)

  • Choi, Hayeon;Yun, Jiwan;Park, Seoyeon;Kim, Yesol;Park, Sangsoo
    • Journal of Korea Multimedia Society
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    • v.18 no.6
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    • pp.723-733
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    • 2015
  • High availability is of utmost importance in real-time embedded systems. Temporary failures due to software or hardware faults should not result in a system crash. To achieve high availability, embedded systems typically use a combination of hardware and software techniques. A watchdog timer is a hardware component in embedded microprocessors that can be used to automatically reset the processor if software anomalies are detected. The embedded system relies on a single watchdog timer, however, can be permanently disabled if the timer is not properly configured, e.g. falling into an indefinite loop. STM32F4 provides two different types of watchdog timer in terms of timing accuracy and robustness. In this paper, we propose a hybrid approach, called long-tail watchdog timer, to utilize both timers to achieve self-reliance in embedded systems even though one of timers fails. Experimental results confirm that the proposed approach successfully handles various failure scenarios and present performance comparisons between single watchdog timer and hybrid approach in terms of configuration parameters of watchdog timers in STM32F4, counter value and window size.

A New input-filtering method for High Speed Counter module of PLC using embedded timer pulse function of general purpose MPU (범용 MPU 내장 타이머 펄스 출력을 이용한 PLC 고속 카운터 모듈의 입력 필터링 기능 개선)

  • Park, Kang-Hee;Lee, Sang-Beak;Han, Kyoung-Sik
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1798-1799
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    • 2011
  • In this paper, A new cost-effective and accurate input noise rejection method for High Speed Counter module of PLC (Programmable Logic Controller) is proposed. By using combination of simple additional logic circuit and the Timer Pulse function of general purpose MPU, Cost-effectiveness and improvement of accuracy of filtering function can be achieved. This proposed method is verified by simulation. This proposed method is much useful for simple industrial controller based on simple microprocessor because of simplicity, accuracy and low cost.

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Dynamic Modeling and Control of Electronic Timer in Fuel Injection System of Light-Duty Diesel Engines (소형디젤엔진용 연료분사장치 전자타이머의 동적모델링과 제어)

  • 한도영;김증열
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.6
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    • pp.196-204
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    • 1996
  • The simplified dynamic models of the timer assembly in the diesel engine fuel injection system were developed. The first order system with time delay was assumed and the various parameters in this model were obtained by experimental data. These simplified dynamic models were used for the development of control algorithm of the injection timing control system. The PI control algorithm was modified to include the anti-windup property and disturbance compensation. This modified PI control algorithm was used for the control of the injection timing. Improved control accuracy and reduced control efforts were observed.

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Development of a oscillating frequency measurement and adjustment system of a balance wheel of Mechanical Timer (기계식 타이머 밸런스 휠의 진동 주파수 측정 및 조정 장비의 개발)

  • Lee, D.J.;Park, S.B.;Ahn, J.H.
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.879-883
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    • 2000
  • A system for measuring and adjusting the oscillating frequency of a balance wheel whick determins the accuracy of mechanical timers. The balance wheel oscillates rotatively suspended by a hair spring which is welded at the other end to the pivot tube. The natural oscillatory frequency of the balance wheel is determined by the length of hairspring from the balance wheel to the point if other parameters the length in the torsional oscillation model are not changed, so the frequency of the balance wheel can be adjusted to meet a requirement by the adjustment of the hairspring length using ultrasonic welding. And the movement of wheel teeth is measured in realtime by a high speed photo fiber sensor and Auto Correlation is used to find a more accurate oscillation period from the measured signal with some variations.

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Delay Performance Analysis of the NAK-based SR-ARQ Protocol with the Reverse Acknowledgment (RA) Scheme

  • Han, Je-Chan;Lee, Jai-Yong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.11B
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    • pp.989-997
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    • 2008
  • The reverse acknowledgment (RA) scheme supports a fast loss recovery for negative acknowledgment (NAK)-based selective repeat automatic repeat request (SR-ARQ) by detecting a retransmission failure quickly before a retransmission timer expires. In this paper, we evaluate the performance of a NAK-based SR-ARQ protocol with the RA scheme and compare it with the conventional NAK-based SR-ARQ protocol. Particularly, we propose a simple analysis model for the transport delay of the NAK-based SR-ARQ protocol considering the traffic condition, the retransmission persistence, the timer-based retransmissions and the RA scheme's behavior. Both NAK-based SR-ARQ protocols with and without the RA scheme are implemented by using the OPNET simulator. We verified the analysis model's accuracy through the simulation results. Also, we evaluate the performance of the NAK-based SR-ARQ protocol with the RA scheme based on analysis and simulation results.

Uncertainty Characteristics of Diverter for Flowmeter Calibration System (액체용 유량계 교정시스템의 Diverter 불확도 특성 연구)

  • Lee, Dong-Keun;Park, Jong-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.11 no.3
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    • pp.50-55
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    • 2008
  • The diverter system is a key component in achieving a high accuracy liquid flow rate standard using a static gravimetric system with a flying start and stop method. The diverter is a moving device used to direct flow alternately along its normal course(by pass) or towards the weighing tank. The time needed for collection into the weighing tank is measured using a timer. So it is important to the diversion period is sufficiently fast and triggering point of timer which is determined the filling time. On this studies show that uncertainty of diverter system for changing diversion speed and triggering point was estimated in accordance with Guide to The Expression of Uncertainty in Measurement(ISO).

High precision Gating Algorithm for Predictive Current Control of Phase Controlled Rectifier (위상제어 정류기의 예측전류제어를 위한 새로운 고정밀 게이팅 알고리즘)

  • 정세종;송승호
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.3
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    • pp.206-211
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    • 2004
  • In phase controlled rectifier, it's been known that a fast response is achieved by predictive current control without any overshoot. The frequent sampling period is essential to improve the firing accuracy in conventional predict current control. However, improving the firing accuracy if difficult to reduce the period of sampling efficiently because current sampling and predictive current control is carried out in every period and the ON-OFF current control is performed by comparing two different one. To improve the firing accuracy at the predictive current control, the calculated firing angle is loaded into the high-accuracy hardware timer. So the calculation of exact crossing point between the predictive and actual current is the most important. In this paper, the flow chart for proposed firing angle calculation algorithm is obtained for the fastest current control performance in transient state. The performance of proposed algorithm is verified through simulations and experiments.

Improvement of Uncertainty for Gravimetric Flow Calibrator (10톤 용량의 중량식 교정장치에 대한 불확도 개선)

  • Lee, Dong-Keun;Park, Joo-Young;Lee, Haeng-Soo
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1042-1046
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    • 2008
  • Both the weighing bridge and the diverter system is a important component in achieving a high accuracy liquid flow rate standard using a static gravimetric method. The weighing bridge is a tank which weighing collected flow with a load cells. The diverter is a moving device used to direct flow alternately along its normal course(by pass) or towards the weighing tank. The time needed for collection into the weighing tank is measured using a timer. So it is important to the diversion period is sufficiently fast and triggering point of timer which is determined the filling time. On this studies show that the measurement deviation of load cell and uncertainty of diverter system for changing diversion speed and triggering point was estimated in accordance with Guide to The Expression of Uncertainty in Measurement(ISO).

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