• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.168-172
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• 1993

As the worst-case analysis for interval plants, a conjecture whether the supremum of the integral of square error(ISE) is attained at the extreme point such as vertices, Kharitonov vertices, CB segment, and edges is suggested. We present a sufficient condition for which the worst performance index occurs at one ofvertices of uncertain parameter space. Numerical examples are also given.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.984-987
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• 1996

We consider a feedback control system including interval plant where uncertain parameters expressed in the hyperrectangular box X. Here we define the maximum value of the integral of the error(ISE) as the worst performance index(WPI) due to the plant parameter uncertainty. Suppose that the closed loop system retains robust stability and it belongs to type I. Then we show that the WPI occurs only on the exposed edges of Q. In particular, it is also shown that if ISE is a convex function relative to X, the WPI is attained at one of vertices of X. Some examples are given.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.30-36
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• 2011

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situation including the worst case such as rollover, spin-out and so on. Although the known NHTSA Sine with dwell steering maneuvers are applied for the vehicle performance assessment, they aren't enough to estimate other possible worst case scenarios. Therefore, it is crucial for us to verify the various worst cases including the existing severe steering maneuvers. This paper includes useful worst case based upon the existing worst case scenarios mentioned above and worst case evaluation for vehicle dynamic controller in simulation basis and UCC HILS. The only human steering angle is selected as a design parameter here and optimized to maximize the index function to be expressed in terms of both yaw rate and side slip angle. The obtained scenarios were enough to generate the worst case to meet NHTSA worst case definition. It has been concluded that the new procedure in this paper is adequate to create other feasible worst case scenarios for a vehicle dynamic control system.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.1-9
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• 2008

The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situation including the worst case such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they aren't enough to estimate other possible worst case scenarios. Therefore, it is crucial for us to verify the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios mentioned above and its application in simulation basis. The only human steering angle is selected as a design parameter here and optimized to maximize the index function to be expressed in terms of either roll angle or yaw rate. The obtained scenarios were enough to generate the worst case to meet NHTSA worst case definition (ex.2-inch wheel lift). Additionally, as an application, the worst case steering maneuver is acquired for the vehicle to operate with a simple ESP system. It has been concluded that the new procedure in this paper is adequate to create other feasible worst case scenarios for a vehicle system both with an intelligent safety control system and without it.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.1976-1978
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• 2001

In this paper, a new robust deadbeat minimax FIR filter (DMFF) is proposed for continuous-time state space signal models. Linearity, deadbeat property, FIR structure, and independence of the initial state information will be required in advance, in addition to a performance index of the worst case gain between the disturbance and the current estimation error. The proposed DMFF is obtained by directly minimizing a performance index with the deadbeat constraint. The proposed DMFF is represented first in a standard FIR form and then in an iterative form. The DMFF will be shown to be used also for the IIR structure. It is shown that the DMFF is similar in form to the existing receding horizon unbiased FIR filter (RHUFF) with some noise covariances. The former is a deterministic filter, while the latter is a stochastic filter.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.531-536
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• 2007

This paper presents a power quality assessment model based on the Analytic hierarchy process. This model can assess unified power quality index which provide an overall performance of the distribution system. To obtain the unified power quality index, we propose the use of the AHP model which has three states: [Ideal]-[Actual]-[Worst]. The proposed method is especially useful and effective for planning. We have applied the proposed method to an actual relatively large system, and verified the usefulness.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.04a
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• pp.37-41
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• 1984

The error rate performance of amplitude phase keying system has been studied in the environment of cochannel interference and impulsive noise. We have derived the error probability equations of amplitude shift keying signal and phase shift keying signal, and combining the results, we have evaluated the circular APK signal which is the one of the several cases of APK arrays. Using the derived equations, the circular APK system has been evaluated in terms of carrier-to-noise power ratio(CNR), carrier-to-interferer power ratio(CIR), and impulsive index. The graphic results show us the best case and worst case of APK system, and good performance compared to the other systems in cochannel interference and impulsive noise.

• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.117-124
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• 2003

Elastohydrodynamic lubrication (EHL) film is measured under the condition of viscosity index improver added to base oil. In-situ optical contact method using the interference principle make the measuring resolution of ~5 nm possible and enables the measuring range all over the contact area of up to ~300 $\mu\textrm{m}$ diameter. What is more important to the developed method by the author is that the measurement of EHL film thickness is possible in the range from 100 nm to 2 $\mu\textrm{m}$, which is the regime of worst contact failures in precision machinery. Viscosity index improver (VII) is one of the major additives to the modem multigrade lubricants for the viscosity stability against temperature rise. However, it causes shear thinning effects which make the film thickness lessened very delicately at high shear rate (over $10^5 s^{-1}$) of general EHL contact regime. In order to exactly verify the VIIs performance of viscosity stability at such high shear rate, it is necessary to make the measurement of EHL film thickness down to ~100 nm with fine resolution for the preliminary study of viscosity control. In this work, EHL film thickness of VII added lubricant is measured with the resolution of ~5 nm, which will give very informative design tool for the synthesis of lubricants regarding the matter of load carrying capacity at high shear rate condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.4
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• pp.499-504
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• 2002

In this paper, we analyzed the performance of FH/CPFSK system with differential detection in thermal noise, partial-band jamming noise and adjacent interference of all eight bit pattern. The parameters to analize performances of FH/CPFSK system have been used the bit rate, modulation index and performances of FH/CPFSK system with the differential detector have been presented with the optimum correlation function. And, we were compared with performance of FH/CPFSK and FH/BFSK system. In result, we could know that bit error probability of the approximation equation and exact equation nearly accorded in the high signal-to-noise ratio. And, we have been proved that FH/CPFSK system with differential detection according to jamming fraction ${\gamma}$ was worst to 3dB than FH/CPFSK system with limiter-discriminator. but was superior to 2dB than FH/BFSK.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.67-72
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• 2014

PURPOSES : This study focuses on conducting pavement rehabilitation for more deteriorated roads given a limited government budget. METHODS : Therefore, we apply a optimization programming model of the permutation algorithm used for rehabilitating more deteriorated pavement areas, which is subjected to the limited budget. RESULTS : The permutation algorithm was evaluated in terms of determining the maximized rehabilitation of deteriorated pavement areas, using the newly developed performance models such as fatigue cracking, rutting, international roughness index(IRI) through the surveying data from 2006 to 2012. When compared with a traditional model of the so-called worst-first sequence(WFS) method, the permutation algorithm worked better than the WFS method, resulting in covering more deteriorated pavement areas given the limited government budget. CONCLUSIONS : Through a case study, it could be concluded that the permutation algorithm provides more reliable results in terms of rehabilitating more deteriorated pavement areas given the limited budget.