• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1460-1463
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• 1997

The aim of this paper is to suggest a design method of the model following optimal boiler-turbine H.inf. control system using genetic algorithm. This boiler-turbine H.inf. control system is designed by applying genetic algortihm with reference model to the optimal determination of weighting functions and design parameter .gamma. that are given by Glover-Doyle algornithm whch can design H.inf. contrlaaer in the sate. space. The first method to do this is ghat the gains of weightinf functions and .gamma. are optimized simultaneously by genetic algroithm. And the second method is that not only the gains and .gamma. but also the dynamics of weighting functions are optimized at the same time by genetic algonithm. The effectiveness of this boiler-turbine H.inf. control system is verified and compared with LQG/LTR control system by computer simulation.

• The Journal of Information Systems
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• v.23 no.1
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• pp.185-202
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• 2014

ERP, a typical enterprise application, helps companies to increase their productivity and to support their decision makings. ERP is composed of diverse functions that are optimized under PC environment, whereas the ERP applications on a mobile platform have many constraints such as a small screen, limited resolution, and computing power. Because all the functions of a ERP legacy system are not required for ERP on a mobile device, the core functions of the ERP system should be selected to increase system efficiency. In this study, two main methods were used; interviews and log analyses. The end users using a ERP system were interviewed for their perceptions, and log data analyses were made for the hitting number of specific ERP functions. The differences between the actual usage based on log data and users' cognitive preferences about ERP functions were analysed. Finally, the functional differences between users' perception and actual usage were suggested for some practical implications.

• Journal of Technology Innovation
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• v.5 no.1
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• pp.150-180
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• 1997

This article introduces the five functions of the national innovation system(NIS). As one of social systems in the national level, the five generic functions of open system - production, boundary spanning, maintenance, adaptation, management functions - are applied to the NIS. The production function is the primary process, which produces innovative products and services of the NIS. The boundary spanning function is the function of procuring input and disposing the innovation output or aiding in these processes. Experienced R&D human resources, R&D funds, technology etc. are some of the components of the input of the NIS. The maintenance function is responsible for maintaining smooth operation and upkeeping the system in terms of various conditions. The adaptation function is to help the system change and adapt, and scan the environment for problems, opportunites, and technological developments. It has outward orientation, from the long-term view for the survival of the system. The management function carries out planning and control of the overall activities for the other four functions in order to effectiving run the system as a whole. Finally, this article discusses implications of the diagnosis of the national innovation system and the decision making process of S&T policy.

• Journal of KSNVE
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• v.9 no.4
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• pp.778-784
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• 1999

A method for obtaining the motion of an impact system whose primary and secondary system are composed of lumped masses, springs and dampers, and all the contacts are made through spring and damping elements is presented. The frequency response functions derived from the equations of motion and the impulse response functions obtained from the inverse Fourier transform of the derived frequency response functions are used for the calculation of the system responses. The procedure developed for the calculation of displacements and force time-histories was based on the convolution integrals of impulse response functions and forces applied to the systems. Time histories of displacements and contact forces are obtained for the case where a random excitation is applied to a point in the system. Impact statistics such as contact forces and the time between impacts calculated from those time histories is presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.87-92
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• 2008

In this paper, certain scaling functions are generated using the dyadic subband tree structure and applied to a time-hopping, pulse position modulation, ultra-wideband (TH-PPM UWB) system. Scaling functions can be obtained by iterating a lowpass filter at each level using a critically sampled dyadic tree. The performance of the TH-PPM UWB system employing scaling functions as the mono-cycle waveform is evaluated through computer simulations in a Rayleigh fading environment.

• Journal of applied mathematics & informatics
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• v.23 no.1_2
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• pp.345-352
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• 2007

In this paper, cone-valued Lyapunov functions are employed to study the impulsive control system with variable times. The stability criteria on the non-zero solution of the impulsive control system are given by the cone-valued Lyapunov functions and the results of the controllability on the control system are also obtained.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.3 s.258
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• pp.365-372
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• 2007

Revisited in this paper are Green's functions for unit concentrated forces in an infinite orthotropic Kirchhoff plate. Instead of obtaining Green's functions expressed in explicit forms in terms of Barnett-Lothe tensors and their associated tensors in cylindrical or dual coordinates systems, presented here are Green's functions expressed in two quasi-harmonic functions in a Cartesian coordinates system. These functions could be applied to thin plate problems regardless of whether the plate is homogeneous or inhomogeneous in the thickness direction. With a composite variable defined as $z=x_1+ipx_2$ which is adopted under the necessity of expressing the Green's functions in terms of two quasi-harmonic functions in a Cartesian coordinates system Stroh-like formalism for orthotropic Kirchhoffplates is evolved. Using some identities of logarithmic and arctangent functions given in this paper, the Green's functions are presented in terms of two quasi-harmonic functions. These forms of Green's functions are favorable to obtain the Newtonian potentials associated with defect problems. Thus, the defects in the orthotropic plate may be easily analyzed by way of the Green's function method.

• East Asian mathematical journal
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• v.37 no.1
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• pp.109-122
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• 2021

We establish existence and uniqueness of Green functions for flow velocity of stationary Stokes systems, under a continuity assumption of weak solutions to the system, in a bounded domain such that the divergence equation is solvable there. We also obtain pointwise bounds of the Green functions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.383-386
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• 2006

The safety of the railway system is important because the system is a mass transit system and the results of the accident are inconceivable. The railway system is operated by train operation system such as train control system. So the train control system requires safety critical characteristics. In the European railway, ETCS (European Train Control System) project has been finished to accomplish the interoperability of each national railway signaling system. According to the interoperability degree, ETCS levels are suggested. As the highest level, ETCS level 3 suggests a radio communication. Also recently urban railway system is operated by driverless and automatic train control system. In this circumstance, more safety is required than before in the railway system. In order to accomplish the safety of a system, the requirements considering safety have to be suggested. The requirement is a set of several functions such as general function, environment, safety etc. For the safety critical system, safety function is more important than any other functions. The safety functions are deduced by safety analysis. In order to perform the safety analysis, the system hazards have to be identified and then risk analysis for each hazard should be performed. The risk is related to the frequency and the severity of each hazard. And then countermeasures for each risk have to be prepared. The summary of the countermeasures is about a kind of safety functions in a system. In this paper, the safety functions for a train control system are presented according to the above procedure.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.28-34
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• 2006

Recently, in accordance with the development of IT technology, it is prevalent for power quality monitors to be connected to each other via networks and share their data because such networks provide system-wide insights to customers concerning power quality. Those systems can alarm and display power quality events for the convenience of customers. However, if a power quality event occurs, it is difficult for customers to determine its cause and solution because the systems do not provide appropriate power quality diagnosis functions. The power quality management system presented in this paper has been developed to provide customers with various power quality diagnosis functions so that they can cope well with power quality problems with the right measure in the right place. This paper presents the structure and functions of the developed power quality management system and shows some results of the power diagnosis functions.