• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.92.1-92
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• 1999

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.3
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• pp.322-333
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• 2012

AESA radar is able to instantaneously and adaptively position and control the beam, and such adaptive beam pointing of AESA radar enables to remarkably improve the multi-mission capability. For this reason, Radar Resource Management(RRM) becomes new challenging issue. RRM is a technique efficiently allocating finite resources, such as energy and time to each task in an optimal and intelligent way. Especially radar beam scheduling is the most critical component for the success of RRM. In this paper, we proposed a rule-based scheduling algorithm and Simulated Annealing(SA) based scheduling algorithm, which are alternatively selected and applied to beam scheduler according radar load status in real-time. The performance of the proposed algorithm was evaluated on the multi-function radar scenario. As a result, we showed that our proposed algorithm can process a lot of beams at the right time with real time capability, compared with applying only rule-based scheduling algorithm. Additionally, we showed that the proposed algorithm can save scheduling time remarkably, compared with applying only SA-based scheduling algorithm.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1654-1663
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• 2015

Compared to LC resonance, LCL resonance has distinct advantages such as a large resonant capability, low voltage and current stresses of the power device, constant voltage or current output characteristics, and fault-tolerance capability. Thus, LCL resonant compensation is employed for a movable Inductive Contactless Power Transfer (ICPT) system with a multi-load in this paper, which achieves constant current output characteristics. Peculiarly, the primary side adopts a much larger compensation inductor than the primary leakage inductor to lower the reactive power, reduce the input current ripple, generate a large current in the primary side, and realize soft-switching. Furthermore, this paper proposes an approximate resonant point for large inductor-ratio LCL resonant compensation through fundamental wave analysis. In addition, the PWM control strategy is used for this system to achieve constant current output characteristics. Finally, an experimental platform is built, whose secondary E-Type coils can ride and move on a primary rail. Simulations and experiments are conducted to verify the effectiveness and accuracy of both the theory and the design method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1479-1484
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• 2014

This paper deals with regenerative energy in railway system which one of the largest customer in terms of load capability. Unlike the other loads of power system, loads of railway systems change in time and space. It has a characteristic amount of generating regenerative energy by frequent starting and braking in railway system. Therefore, it is expected higher utilization in railway system than the other systems. The purpose of DC power supply simulation is analyzing backed energy, regenerative energy by each railway vehicle and substation. In this paper, regenerative energy utilization are analyzed using DC power supply simulation and it is performed changing major influence on the design such as the number of installing absorber, internal resistance value, no-load voltage value at substation or operating parameters at regenerative energy utilization. After simulating, results are compared and analyzed.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.94-103
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• 1997

It is necesary that analog buffer circuit should drive an external load in the VLSI design such as switched capacitor efilter (SCF), D/A converter, A/d converter, telecommunicatin circuit, etc. The conventional CMOS buffer circuit have many probvlems according as CMOS technique. Firstly, Capacity of large load ar enot able to opeate well. The problem can be solve to use class AB stages. But large load are operated a difficult, because an element of existing CMOS has a quadratic functional relation with inptu and outut voltage versus output current. Secondly, whole circuit of dynamic rang edecrease, because a range of inpt and output voltages go down according as increasing of intergration rate drop supply voltage. In this paper suggests that new differential CMOS line driver make out of operating an external of large load. In telecommunication's chip case transmission line could be a load. It is necessary that a load operate line driver. The proposal circuit is planned to hav ea high generation power rnage of voltage with preservin linearity. And circuit of capability is inspected through simulation program (HSPICE).

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.869-871
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• 1998

The extensive use of composite insulators for transmission lines can ultimately be justified only on long-term qualification tests. The actual load working on the insulator in the field is not static load but cyclic load. So in this paper, we discussed an examination of aging degradation by mechanical performance of composite insulators under static tension load and cyclic tension load. and also described useful approaches for analyzing their long term performance so as to develop reliable composite insulators. The static and cyclic tension load-time test data were examined by Weibull distribution for their capability of presuming long term performance. It was found that cyclic tension loads were more severe than static tension loads. The results also indicate that it may be relevant for an user to select composite insulators on basis of their performance under cyclic tension loads than static tension loads.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.790-793
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• 2001

The characteristics of smart skin for wireless LAN system under compression load are investigated. The smart skin structure is composed of 3 layers of face material and 2 layers of core material. Theoretical formula for determining buckling load is derived by Rayleigh-Ritz method and compared with experimental result. The maximum length of specimen that buckling does not occur is determined by assuming that the compression load is sustained by only face material. In the experiment, if buckling occurs obviously then it follows the theoretical result well. In the process of buckling, the load supporting capability and the antenna property such as radiation pattern and reflection coefficient were examined.

• Composites Research
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• v.28 no.5
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• pp.297-310
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• 2015

This study aims to develop efficient composite laminates for buckling load enhancement, interlaminar shear stress minimization, and weight reduction. This goal is achieved through cover-skin lay-ups around skins and stiffeners, which amplify bending stiffness and defer delamination by means of effective stress distribution. The design problem is formulated as multi-objective optimization that maximizes buckling load capability while minimizing both maximum out-of-plane shear stress and panel weight. For efficient optimization, response surface methodology is employed for buckling load, two out-of-plane shear stresses, and panel weight with respect to one ply thickness, six fiber orientations of a skin, and four stiffener heights. Numerical results show that skin-covered composite stiffened panels can be devised for maximum buckling load and minimum interlaminar shear stresses under compressive load. In addition, the effects of different material properties are investigated and compared. The obtained results reveal that the composite stiffened panel with Kevlar material is the most effective design.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3685-3693
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• 2021

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.457-466
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• 2013

Wind energy is rapidly becoming significant generating technologies in electricity markets. As probabilistic nature of wind energy creates many uncertainties in the short-term scheduling, additional actions for reliable market operation should be taken. This paper presents a novel approach to evaluate ramping capability requirement for changes in imbalance energy between day-ahead market and real-time market due to uncertainty of wind generation as well as system load. Dynamic ramp rate model has been applied for realistic solution in unit commitment problem, which is implemented in day-ahead market. Probabilistic optimal power flow has been used to verify ramping capability determined by the proposed method is reasonable in economic and reliable aspects. This approach was tested on six-bus system and IEEE 118-bus system with a wind farm. The results show that the proposed approach provides ramping capability information to meet both forecasted variability and desired confidence level of anticipated uncertainty.