• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.539-545
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• 2010

Through the AUTOSAR methodology, the embedded software shall become more flexible, reusable, maintainable than ever. However, it is not mentioned about specific timing constraints of software components in AUTOSAR. There are a few basic principles for mapping runnable entities. At this point, AUTOSAR software design with optimal scheduling method is one of the enabling technologies in vehicle embedded system. This paper presents an approach based on mapping runnable entities and task scheduling design method for EPS (Electric Power Steering) software components, based on AUTOSAR. In addition, the experimental results of concurrent simulation show that the proposed scheduling technique and timing synchronization in the software component design can achieve the improved torque ripple performance and it well suited for EPS application software.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.286-293
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• 2004

The air fuel ratios of current gasoline engines are almost controlled by several air flow meters. When CVVT (Continuous Variable Valve Timing) is applied to a gasoline engine for higher engine performance, the MAP (Manifold Absolute Pressure) sensor is difficult to follow the instantaneous air fuel ratio due to the valve timing effect. Therefore, a HFM (Hot Film Flow Meter) is widely used for measuring intake air flow in this case. However, the HFMs are incapable of indicating to reverse flow, the oscillation of intake air flow has an negative effect on the precision of the HFM. Consequently, the various duct configurations in front of the air flow sensor affect the precision of HFM sensitivity. This paper mainly focused on the analysis of the reverse flow, flow fluctuation in throttle upstream and the geometry of intake system which influence the HFM measurement.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.771-774
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• 1999

This paper presents a new timing structure for real time communications and its performance analysis. The cycle time consists of several "one time slot" which may be an interval defined by a synchronous traffic part followed by an asynchronous traffic part. If a station receives a token within a synchronous interval, it transmits its synchronous message if any, otherwise it may transmit an asynchronous message. This scheme is different from usual allocation schemes which divide one cycle into alternating synchronous and asynchronous subslots. This protocol is designed to prevent low priority messages from delaying too much due to lots of high priority messages. We propose the algorithm and show its justification by simulation.

• Tribology and Lubricants
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• v.22 no.1
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• pp.14-19
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• 2006

VCT(Variable Cam Timing) system is one of very useful engine components to improve fuel economy and overcome emission regulation etc. In order to adapt the VCT to a base engine, many design mod ifications in the mechanical and lubrication fields are required. Especially, because the VCT performance itself depends on supplied oil flow rate and pressure, it is very important to evaluate the engine lubrication system in a viewpoint of supplied oil flow rate and pressure. In this paper, unsteady transient flow network analysis on the engine oil circuit system was carried out to do this.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.369-378
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• 1988

In this paper, the performance of the timing jitter which has great effects on the echo canceller that can be used for full-duplex digital transmission on two-wire subscriber loops is analyzed. The power spectrum of timing jitter is about 8.9dB lower in the AMI input format than in the Polar-NRZ-L input format. The performance of the echo canceller also has been shown improved by 4dB when the input signal is in the AMI format.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.101-116
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• 2002

Modern vehicles require a high degree of refinement, including good driveability to meet customer demands. Vehicle driveability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore, Engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes analysis procedures using a mathematical model which has been developed to simulate spark timing control logic. Inertia mass moment, stiffness and damping coefficient of engine and drive train were simulated to analyze the effect of parameters which were related vehicle dynamic behavior. Inertia mass moment of engine and stiffness of drive line were shown key factors for the shuffle characteristics. It was found that torque increase rate, torque reduction rate and torque recovery timing and rate influenced the shuffle characteristics at the tip-in condition for the given system in this study.

• Journal of ILASS-Korea
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• v.22 no.1
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• pp.22-28
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• 2017

In this study, the effects of intake valve closing timing by using Cam-in-Cam system on combustion and emission characteristics for diesel engine were investigated under GT-POWER simulation environment. As a result, it was found that volumetric efficiency and effective compression ratio were decreased as the intake valve closing(IVC) timing is retarded due to its backflow effect. Also, we found that in-cylinder pressure, heat release rate and NOx emission were decreased as IVC timing was retarded. These show that the LIVC(late intake valve closing) can be effective to control AFR and mixing rate in diffusion combustion of diesel engine.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.603-605
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• 1998

In recent years, chip delay estimation has had an increasingly important impact on overall design technology. The analysis of the timing behavior of an ASIC should be based not only on the delay characteristics of gates and interconnect circuits but also on the interactions between them. This model plays an important role in our CAD system to analyze the ASIC timing characteristics accurately, together with two-dimensional gate delay table model, AWE algorithm and effective capacitance concept. In this paper, we present an efficient algorithm which accounts for series resistance by computing a reduced-order approximation for the driving-point admittance of an RC-tree and an effective capacitance equation that captures the complete waveform response accurately.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.52-60
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• 1993

Fluttering ghost which is the most severs picture impairment in mobile TV reception under multipath fading environments can be detected by measuring the dynamic variation of the synchronizing pulse timing. And also, the occurrence-stucture of fluttering ghost are directly correlated with the multipath parameters. This paper describes the quantitative evaluating method of the mobile TV pictures impaired by multipath parameters by means of the spectral analysis of synchronizing timing fluctuation. The ghost-flutter curve derived from the spatial amplitue spectrum of synchronizing pulse timing fluctuation express well the spatial variation characteristic, and it has been found to be the quantitative evaluating measure of picture impairment in mobile reception. A correspondence between the ghost-flutter curve (and/or index) and picture quality opinion test results is established.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.215-218
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• 2003

A 2R O/E/O wavelength converter is useful for bit rate transparency, though it has a limit on cascadability due to timing-jitter accumulation. In this paper, we propose a nonlinear signal model which is more practical than the commonly used sine wave model. With our model, we theoretically analyzed the effects of timing-jitter and the cascadability of a 2R O/E/O wavelength converter. To confirm the theoretical results, we measured the cascadability in a 40-km re-circulation loop for 10 Gb/s signal.