• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.494-496
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• 1999

In this paper, we consider the design of a state feedback $H_{\infty}$ controller for uncertain linear systems with saturating actuators. We consider a general saturating actuator and employ the additive decomposition to deal with it effectively. And the considered uncertainty is the unstructured uncertainty which is only known its norm bound. Based on Linear Matrix Inequality(LMI) techniques, we present a condition on designing a controller that guarantees the $L_2$ gain, from the noise to the output, is not greater than a given value. A controller is obtained by checking the feasibility of three LMI's, and this can be easily done by well-known control package. Finally, we show the usefulness of our result by a numerical example.

• Electronics and Telecommunications Trends
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• v.24 no.2
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• pp.111-119
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• 2009

세계의 방송 통신환경은 글로벌화 되고 있으며 주요 기업간 M&A로 업계 재편이 본격화 되고 있다. 통신산업 환경이 개방화 글로벌화 되어 가는 과정에서 국내 통신산업도 경쟁력을 가지기 위해서는 해외시장 확보와 규모의 경제 달성이 필요하다. 국내 통신산업은 국제적 경쟁력을 갖추고 있음에도 이를 활용한 해외진출은 미흡한 실정이다. 국내 통신사업자가 글로벌 통신시장에 진출하여 해외 통신사업자들과 본격적으로 경쟁하기 위해서는 자본 확충과 다양한 정부 지원이 필요하나 이를 확보하기에 많은 애로점이 있다. 본 고에서는 이러한 문제를 해결하기 위한 하나의 대안으로서 정부의 주요 국정 과제 중 하나인 자원외교와 연계한 통신서비스 산업의 패키지형 해외진출 전략을 제안한다. 본 고에서 제안하는 패키지형 진출 전략의 핵심은 우리나라와 자원부국간의 상생과 자원 IT 금융의 산업간 시너지를 도출하는 데 의의가 있다.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.596-598
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• 1999

In this paper, we consider the design of a state feedback $H_{\infty}$ controller for linear systems with saturating actuators. We consider a general saturating actuator and employ the multiplicative decomposition to deal with it effectively. Based on Linear Matrix Inequality (LMI) techniques, we present a condition on designing a controller that guarantees the $L_2$ gain, from the noise to the output, is not greater than a given value. A controller is obtained by checking the feasibility of three LMI's, and this can be easily done by well-known control package. Finally, we show the usefulness of our result by a numerical example.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.133.4-133
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• 2001

In the paper, a Visual factory model for a optical-components manufacturing process is built. The optical-components manufacturing process is composed of 3 operation processes; optical sub assembly process, package assembly process, and fiber assembly process. Each process is managed not a batch mode, which is one of most popular manufacturing styles to produce a great deal of industrial output, but though a modular cell. In the processes, a modular cell has to be processed independently of the other cells. Optimization for the composition of assembly cell in the optical-components system is made by the Visual factory model.

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.229-233
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• 1997

The demand to increase productivity and quality, the shortage of skilled labour and the strict health and safety requirements have led to the development of the automated welding process to deal with many of the present problems of welded fabrication. To make effective use of the automated arc welding process, it is imperative that a mathematical model, which can be programmed easily and fed to the robot, should be developed. The objectives of the paper are to develop the mathematical equations (linear and curvilinear) for study of the relationship between process variables and bead geometry by employing a standard statistical package program, SAS and to choose the best model for automation of the $CO_2$ gas arc welding process. Mathematical models developed from experimental results can be employed to control the process variables in order to achieve the desired bead geometry based on weld quality criteria. Also these equations may prove useful and applicable for automatic control system and expert systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.107-112
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• 1998

A great deal of time and effort are required to evaluate the safety and durability of a vehicle structure in the vehicle development stage. It is difficult to find the reasons for cracks which occur in the body and frame of a vehicle during tests. Recently computer aided engineering techniques have been utilized to solve the problems of safety and durability of vehicles. In this study, a dynamic stress analysis is performed on the frame of the vehicle by rigid and flexible multibody dynamics techniques. The result of the analysis is compared to that of the actual test. The full vehicle dynamic models for the rigid and flexible bodies are developed by DADS package. The modal coordinate system is used to save time for the dynamic stress analysis. The flexible multibody dynamic models have 12 normal modes considering the flexibility of the frame. Dynamic stresses arc calculated by relating the stress influence coefficients and the applied forces.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.115-118
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• 2008

The promotion of overseas projects by construction enterprises has appeared as a way to overcome the current business difficulties of the Korean construction industry, which largely caused by the slow growth of the domestic market and the intensified competition among construction companies. The government has also shown considerable interests in the strategic approach of promoting construction projects by private companies in natural resource-rich countries, which helps the internationalization of Korean companies and the acouisition of natural resources. In this regard, this research examines the status of the construction market in the Democratic Republic of the Congo(DRC) whose potential economic growth is considered as significant, while exploring the appropriate Investment strategies of Korean construction enterprise. Since little appears to be known about the construction market and economic conditions of the DRC, after a documented review of the development trajectory of the country, a field investigation was preformed in June 2008 for obtaining information on the subjects. This research finds that the road construction is the area to fulfill the several important criteria of implementing construction projects in developing regions, including the safety/reliability for gaining investment profits, the possibility of implementing construction projects on the gradual basis, the possibility of using the facilities after the project completion, and the linkage between payment and the construction stages. In regard to the current economic situation of the DRC and the policies of the DRC government, a package deal approach, which contains the exchange of the infrastructure construction by the Korean companies and the provision of natural resources by the DRC government, is the most feasible method for Korean companies to promote their businesses in the DRC's construction market.

• Smart Structures and Systems
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• v.15 no.2
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• pp.299-314
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• 2015

Submersed rock-berm structures are frequently used for protection of underwater lifelines such as pipelines and power cables. During the service life, the rock-berm structure can experience several accidental loads such as anchor collision. The consequences can be severe with a certain level of frequency; hence, the structural responses should be carefully understood for implementing a proper structural health monitoring method. However, no study has been made to quantify the structural responses because it is hard to deal with the individual behavior of each rock. Therefore, this study presents a collision analysis of the submersed rock-berm structure using a finite element software package by facilitating the smoothed-particle hydrodynamics (SPH) method. The analysis results were compared with those obtained from the Lagrange method. Moreover, two types of anchors (stock anchor and stockless anchor), three collision points and two different drop velocities (terminal velocity of each anchor and 5 m/s) were selected to investigate the changes in the responses. Finally, the effect of these parameters (analysis method, anchor type, collision point and drop velocity) on the analysis results was studied. Accordingly, the effectiveness of the SPH method is verified, a safe rock-berm height (over 1 m) is proposed, and a gauge point (0.5 m above the seabed) is suggested for a structural health monitoring implementation.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.389-390
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• 1996

The CCDs are widely used in astronomical observations either in direct imaging use or spectroscopic mode. However, the areas of available sensors are too small for large imaging format. One possibility to obtain large detection area is to assemble mosaics of CCD, and drive them simultaneously. Parallel driving of many CCDs together rules out the possibility of individual tuning; however, such optimisation is very important, when the ultimate low light level performance is required, particularly for new, or mixed devices. In this work, a new concept is explored for an entirely novel approach, where the drive waveforms are multiplexed and interleaved. This simultaneously reduces the number of leadout connections and permits individual optimisation efficiently. The digital controller can be designed within a single EPLD (Erasable Programmable Logic Device) chip produced by a CAD software package, where most of the digital controller circuits are integrated. This method can minimise the component. count., and improve the system efficiency greatly, based on earlier works by Han et a1. (1996, 1994). The system software has an open architecture to permit convenient modification by the user, to fit their specific purposes. Some variable system control parameters can be selected by a user with a wider range of choice. The digital controller design concept allows great flexibility of system parameters by the software, specifically for the compatibility to deal with any number of mixed CCDs, and in any format, within the practical limit.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.543-554
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• 2013

Acoustic Doppler Current Profilers (ADCPs) are increasingly popular in the river research and management communities being primarily used for estimation of stream flows. ADCPs capabilities, however, entail additional features that are not fully explored, such as morphological representation of river or reservoir bed based upon multi-beam depth measurements. In addition to flow velocity, ADCP measurements include river bathymetry information through the depth measurements acquired in individual 4 or 5 beams with a given oblique angle. Such sounding capability indicates that multi-beam ADCPs can be utilized as an efficient depth-sounder to be more capable than the conventional single-beam eco-sounders. The paper introduces the post-processing algorithms required to deal with raw ADCP bathymetry measurements including the following aspects: a) correcting the individual beam depths for tilt (pitch and roll); b) filtering outliers using SMART filters; d) transforming the corrected depths into geographical coordinates by UTM conversion; and, e) tag the beam detecting locations with the concurrent GPS information; f) spatial representation in a GIS package. The developed algorithms are applied for the ADCP bathymetric dataset acquired from Han-Cheon in Jeju Island to validate themselves applicability.