• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.335-335
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• 2000

Applications such as unmanned aerial vehicles (UAVs), autonomous underwater vehicles (AUVs) and the time varying nature of their navigation, guidance and control systems motivate an integrated approach to trajectory general ion and trajectory tracking for autonomous vehicles. In this paper, an experimental testbed was designed for studying this integrated trajectory control approach. In this paper we apply the separating approach to an autonomous nonlinear vehicle system. A new linear matrix inequality based H$_{\infty}$ control technique for periodic time-varying systems is applied to the role of trajectory tracking. Trajectory general ion is accomplished by exploit ing the differential flatness property of the vehicle system; this at lows product ion of desired feasible nominal or reference trajectories from certain ″flat'system outputs. Simulation and experimental results are presented showing stable tracking of a periodic circular trajectory.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.311-316
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• 2012

In this paper, chaotic circuit of the Lorentz system for engineering applications was implemented using resistor, multipliers, capacitors and operational amplifiers. The implemented Lorentz chaotic system was analysed by PSPICE program. PSPICE simulation results show many kind of chaotic phenomena such time waveforms and phase plots. Meanwhile, according to resistor's variation, we got that Lorentz system show equilibrium state, periodic state and chaotic state.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.76-84
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• 2011

Embedded Systems need to ensure real-time of the task response time depending on the applied fields of it. And task could be faulty due to various reasons in real time systems. Therefore in this paper, we design a task scheduler that guarantees deadlines of periodic tasks and considers a fault tolerance of defective task in embedded system with a single processor. In order to provide real-time, we classify tasks with periodic/aperiodic tasks and applies RMS(Rate Monotonic Scheduling) method to schedule periodic tasks and can guarantees execution of aperiodic tasks by managing surplus times obtained after analyzing the execution time of periodic tasks. In order to provide fault tolerance, we manage backup times and reexecute a fault task to restore it's conditions.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.1
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• pp.27-39
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• 2023

This study was to quantitatively evaluate periodic and maximum energy loads for broiler-standard design models by the Ministry of Agriculture, Food and Rural Affairs (2016). Building energy simulation method was used to compute heating and cooling loads of the designed broiler houses according to regional locations and insulation characteristics of wall and roof. It considered sensible and latent heat generation from broilers, dynamic operation of ventilation system according to environment variations. It was found that variation of periodic heating loads was relatively higher than that of periodic cooling loads according to thickness changes of wall and roof. Assuming that broiler was raised at every even-month, periodic heating and cooling loads were 6 and 18% lower, respectively than odd-month raising condition. When recommendation rules of insulation characteristics (wall and roof thickness) by the Ministry of Land, Infrastructure and Transport was adopted, periodic heating load of Jeju-si was 20.3% higher than national average values. Based on the BES computed periodic and maximum energy loads under the designed experimental condition, these results can contribute to reestablishing standard design of broiler houses, especially for insulation characteristics, and designing management strategies for efficient energy uses.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1612-1617
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• 2011

Rolling stock needs many maintenance works because of its long service life. The maintenance of rolling stock has periodic preventive maintenance system. This periodic preventive maintenance system can't reflect the characteristics of every part. The condition-based maintenance system which reflects the functional condition of every part prevents breakdown and reduces maintenance cost. This study will analyze the records of every part by unreasonable examples of time-based preventive maintenance and reliability management activities, and discuss the necessity of maintenance system reflected the results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2620-2631
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• 2012

In this paper, a rerouting-controlled ISL (Inter-Satellite link) handover protocol for LEO satellite networks (RCIHP) is proposed. Through topological dynamics and periodic characterization of LEO satellite constellation, the protocol firstly derives the ISL related information such as the moments of ISL handovers and the intervals during which ISLs are closed and cannot be used to forward packet. The information, combined with satellite link load status, is then been utilized during packet forwarding process. The protocol makes a forwarding decision on a per packet basis and only routes packets to living and non-congested satellite links. Thus RCIHP avoids periodic rerouting that occurs in traditional routing protocols and makes it totally unnecessary. Simulation studies show that RCIHP has a good performance in terms of packet dropped possibility and end-to-end delay.

• Bulletin of the Korean Mathematical Society
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• v.22 no.2
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• pp.95-98
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• 1985

In [1], E.B. Lee and L. Markus described a sufficient condition for which the domain of null-controllability of a linear autonomous system is all of R$^{n}$ . The purpose of this note is to extend the result to a certain linear nonautonomous system. Thus we consider a linear control system dx/dt = A(t)x+B(t)u in the Eculidean n-space R$^{n}$ where A(t) and B(t) are n*n and n*m matrices, respectively, which are continuous on 0.leq.t<.inf. and A(t) is a periodic matrix of period .omega.. Admissible controls are bounded measurable functions defined on some finite subintervals of [0, .inf.) having values in a certain convex set .ohm. in R$^{m}$ with the origin in its interior. And we present a sufficient condition for which the domain of null-controllability is all of R$^{n}$ .

• Bulletin of the Korean Mathematical Society
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• v.49 no.2
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• pp.307-317
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• 2012

We say (W, {${\phi}_1,\;{\ldots}\;,{\phi}_t$}) is a polarizable dynamical system of several morphisms if ${\phi}_i$ are endomorphisms on a projective variety W such that ${\otimes}{\phi}_i^*L$ is linearly equivalent to $L^{{\otimes}q}$ for some ample line bundle L on W and for some q > t. If q is a rational number, then we have the equidistribution of small points of given dynamical system because of Yuan's work [13]. As its application, we can build a polarizable dynamical system of an automorphism and its inverse on a K3 surface and can show that its periodic points are equidistributed.

• Journal of the Korean Mathematical Society
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• v.48 no.6
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• pp.1225-1248
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• 2011

The present paper is concerned with a two-competitor/oneprey population system with Holling type-II functional response and two discrete delays. By linearizing the system at the positive equilibrium and analyzing the associated characteristic equation, the asymptotic stability of the positive equilibrium and existence of local Hopf bifurcations are investigated. Particularly, by applying the normal form theory and the center manifold reduction for functional differential equations (FDEs) explicit formulae determining the direction of bifurcations and the stability of bifurcating periodic solutions are derived. Finally, to verify our theoretical predictions, some numerical simulations are also included at the end of this paper.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.939-941
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• 2001

An efficient control method of ZVS Full-bridge PWM converter with a periodic pulsed-load current is proposed. This novel control method can reduce the switching loss of switches during no load condition. Moreover, by using feed-forwarded load current information this method can obtain better transient dynamics compared to the system with only linear feedback control.