• Title/Summary/Keyword: Timing Analysis

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Bounding Worst-Case Data Cache Performance by Using Stack Distance

  • Liu, Yu;Zhang, Wei
    • Journal of Computing Science and Engineering
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    • v.3 no.4
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    • pp.195-215
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    • 2009
  • Worst-case execution time (WCET) analysis is critical for hard real-time systems to ensure that different tasks can meet their respective deadlines. While significant progress has been made for WCET analysis of instruction caches, the data cache timing analysis, especially for set-associative data caches, is rather limited. This paper proposes an approach to safely and tightly bounding data cache performance by computing the worst-case stack distance of data cache accesses. Our approach can not only be applied to direct-mapped caches, but also be used for set-associative or even fully-associative caches without increasing the complexity of analysis. Moreover, the proposed approach can statically categorize worst-case data cache misses into cold, conflict, and capacity misses, which can provide useful insights for designers to enhance the worst-case data cache performance. Our evaluation shows that the proposed data cache timing analysis technique can safely and accurately estimate the worst-case data cache performance, and the overestimation as compared to the observed worst-case data cache misses is within 1% on average.

The Effect of Electromyographic Biofeedback Training on the VMO/VL Electromyographic Activity Ratio and Onset Timing in Women without Knee Pathology (건강한 여성에 대한 근전도를 이용한 생체되먹이기 훈련이 안쪽빗넓은근과 가쪽넓은근의 근활성비와 개시시간에 미치는 영향)

  • Kim, Hyun-Hee;Song, Chang-Ho
    • Journal of the Korean Society of Physical Medicine
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    • v.5 no.4
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    • pp.605-613
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    • 2010
  • Purpose : The purpose of this study was to investigate the VMO/VL ratio and onset timing using EMG biofeedback training over a 5-day period. Methods : Twenty-one healthy female college students with no known right knee musculoskeletal dysfunction were recruited this study. Muscle activity was measured by surface electromyography(Myosystem 1400A, Noraxon Inc., U.S.A). Statistical analysis was used two-way repeated ANOVA to know difference between the vastus lateralis and vastus medialis oblique onset timing differences, VMO/VL ratio. Results : Biofeedback training group significantly improved VMO/VL ratio and EMG activity of the vastus medialis oblique after intervention. Conclusion : These result indicate that biofeedback training on the vastus medialis oblique has effect on the VMO/VL ratio. EMG biofeedback can be recommended for the facilitation of VMO muscular recruitment.

Optimal Investment Decision Timing Model Using Real Options Approach (실물 옵션을 이용한 최적 투자 의사결정 시기 선택 모형)

  • 이재한;이동주;안재현
    • Journal of the Korean Operations Research and Management Science Society
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    • v.26 no.4
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    • pp.83-97
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    • 2001
  • Net Present Value (NPV) criterion has been the most widely used criterion to evaluate investment opportunities. However, the analysis based on the NPV criterion falls to consider the managerial flexibility of deferring decisions until major uncertainty is resolved. Recently, real options method attracted a lot of attention as a Powerful approach to address the problem. If investment decision is deferred, the value of the investment opportunity increases but opportunity cost increases at the same time. Therefore, it is important to decide the optimal timing how long the decision can be deferred. In this paper, we developed a model deciding the optimal decision timing. Using the real options approach, the model derived the optimal deferring time until a decision is made. Then, the model was applied to a Korean mobile telecommunications company who wants to invest on the wireless resale business. We believe that this model would be very useful to overcome the problem of NPV decision criterion. With this approach, we can make contingent decisions based on the observation of uncertainly resolutions.

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Threshold level analysis of the FFH-MA system using noncoherent FSK modulation under the presence of frequency and timing offsets (주파수와 타이밍 옵셋에 의한 빠른 주파수 호핑 시스템의 임계값 분석)

  • Jeungmin Joo;Yeomin Yoon;Miheung Choe;Lee, Kwangeog;Kim, Kiseon
    • Proceedings of the IEEK Conference
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    • 2003.07a
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    • pp.226-229
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    • 2003
  • Under the prsence of the frequency and timing offset, we evaluate the BER performance of the FFH-MA system using noncoherent M-ary FSK modulation in the Rayleigh fading channel. The numerical resuts show that while the frequency and timing offset increases at a given SNR, the BER is severely degraded. The threshold level used in the envelope detector increases with the increase of the frequency and timing offset, and with the proper selection of the threshold level, the BER can be improved under the presence of such offsets.

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Analysis of OHC drive timing belt system behavior for fixed and automatic tensioner (고정 및 자동장력식 텐셔너에 대한 OHC 구동 타이밍 벨트 시스템의 거동해석)

  • 김현수;이인환;여창기
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.79-89
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    • 1992
  • The behavior of belt tension in OHC drive timing belt system was investigated analytically and experimentally for (1)fixed and (2)automatic tensioner. From the numerical results it was found that the automatic tensioner makes the belt tension larger than those of the fixed tensioner. When the initial belt tension decreased due to the belt elongation, the belt tension of the fixed tensioner could decrease to near zero while the belt tension for the automatic tensioner maintained above zero by the tensioner spring. The mean valve and the difference between the maximum and the minimum belt tension for the automatic tensioner increased compared with those of the fixed tensioner. Also, the numerical results for a hydraulic tensioner showed that the hydraulic tensioner has the good parts of both tensioners; i.e., thesmaller amplitude in belt tension and the higher mean tension. Experimental results for the automatic and fixed tensioner of the OHC timing belt system were in agreement with the theoretical results.

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Analysis of Transmission Error for Stepping Motor Drive Timing Belt System (스테핑 모터 구동 타이밍벨트 시스템의 전동오차 해석)

  • Kim, Hyun-Soo;Wee, Hyuk
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.4
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    • pp.649-657
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    • 1992
  • Transmission error for a stepping motor-timing belt drive system is investigated experimentally and analytically. From FFT analysis of the experimental results, it is found that the transmission error consists of three periodic errors : (1) error by the stepping motor per one resolution angle theta.$_{m}$, (2) error by the pulley eccentricity per one revolution theta.$_{e}$, and (3) error by the meshing effect between the belt and the pulley teeth per one pitch revoltion theta.$_{p}$. In order to investigate the effects of some design parameters on the transmission error, the dynamic models of the stepping motor-timing belt drive system are derived by Bondgraph. According to the simulation results, as the belt total tension increases, theta.$_{m}$ and theta.$_{e}$ decrease due to the nonlinearity of the belt. In adition, the numerical and experimental results show that theta.$_{m}$ and theta.$_{e}$ of the loaded case are larger than those of the unloaded case. The analytical results are in good accordance with the experimental results.sults.s.sults.

The Effect of Fuel Injection Strategy on Combustion and Nano-particle Emissions in a Small Diesel Engine (소형디젤기관의 연료분사조건에 따른 연소 및 미세입자 배출 특성에 관한 연구)

  • Kang, Seok-Ho;Lee, Seang-Wock;Eom, Dong-Seop
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.7
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    • pp.98-106
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    • 2014
  • Emission standards for passenger diesel engines are becoming more and more stringent. Especially, Europe started the regulation of nano-particles from 2011 with EURO 5b. The objective of this study is to investigate the effect of fuel injection strategy on combustion and nano-particle emission in a small diesel engine. In this study, we conducted combustion analysis and measured both the weight of PM and number of nano-particels. At first, the optimum injection timing was determined with fixed engine operating conditions, such as engine speed, load, and fuel injection quantity. After that, the injection timing was controlled, and the effect of pilot injection was investigated. The number of nano-particles increased as engine load decreases, and it increased up to 10 times depending on the change of injection timing. The weight of PM emissions was increased at low load, and the PM emissions increased with increasing the number of pilot injections.

Valuation and Optimal Timing of the Investment in Next Generation Telecommunication Service Using Real Options (실물옵션을 이용한 차세대 정보통신 투자사업의 가치 평가 및 최적 투자시기 결정)

  • Lim, Kum-Soon;Lee, Deok-Joo;Kim, Ki-Hong;Oh, Hyung-Sik
    • Journal of Korean Institute of Industrial Engineers
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    • v.32 no.3
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    • pp.180-190
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    • 2006
  • We evaluate the economic value and the optimal investment timing of IMT-2000 in Korea, in the perspective of a service provider who owns the business license for IMT-2000, by using the real options analysis. The result clearly shows the project value with options is positive and delaying the investment is more favorable to the provider. Binomial lattice approach, in which we try to describe American call option and sequential compound option, and sensitivity analysis present the optimal decisions according to future states and enable the management to make decision strategically and proactively.

A Linear Electromagnetic Motion Device for VVT in Combustion Engine (가변 밸브타이밍을 위한 신개념 전자기 리니어 엑츄에이터)

  • Kim, Jin-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.9
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    • pp.53-58
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    • 2008
  • The traditional engine valve train in a combustion engine is the mechanically driven camshaft system that provides one-fixed valve timing. The variable valve timing (VVT), however, is highly required to achieve the significant improvement in fuel economy. To achieve VVT in combustion engine, the solenoid type of actuator had been developed in past years, but it requires current in all operation period, the starting is difficult and the efficiency is low. In this paper, a new linear actuator using permanent magnet (PM) is proposed and verified its feasibility by finite element (FE) analysis.

Analysis of the Timing of Spoken Korean Using a Classification and Regression Tree (CART) Model

  • Chung, Hyun-Song;Huckvale, Mark
    • Speech Sciences
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    • v.8 no.1
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    • pp.77-91
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    • 2001
  • This paper investigates the timing of Korean spoken in a news-reading speech style in order to improve the naturalness of durations used in Korean speech synthesis. Each segment in a corpus of 671 read sentences was annotated with 69 segmental and prosodic features so that the measured duration could be correlated with the context in which it occurred. A CART model based on the features showed a correlation coefficient of 0.79 with an RMSE (root mean squared prediction error) of 23 ms between actual and predicted durations in reserved test data. These results are comparable with recent published results in Korean and similar to results found in other languages. An analysis of the classification tree shows that phrasal structure has the greatest effect on the segment duration, followed by syllable structure and the manner features of surrounding segments. The place features of surrounding segments only have small effects. The model has application in Korean speech synthesis systems.

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