• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.2
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• pp.53-59
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• 2014

Simultaneous parallel approaches in all weather conditions should be applied to manage efficiently increasing volume of air traffic flow and solve the problem of delayed arrivals. But All of the airports which have closely-spaced parallel-runways in Korea don't meet the interval-standards for IFR parallel approaches. In that regard, more accurate and safer System should be applied for the Korean airports. GNSS was adopted as an international standard of the next-generation navigation system and many studies and master plans have been activated by stages in Korea. In this paper, the current state of the domestic airports will be analyzed focusing on the interval of parallel runways and future specification of both flight operation system and air-side management will be recommended.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.149-151
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• 2008

This paper presents an architecture for driving multiple parallel cold cathode fluorescent lamps (CCFLs) for back lighting applications. The key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.907-915
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• 2002

We present a state-space approach to design a passivity-based dynamic output feedback control of a finite collection of non-square linear systems. We first determine a squaring gain matrix and an additional dynamics that is connected to the systems in a feedforward way, then a static passivating (i.e. rendering passive) control law is designed. Consequently, the actual feedback controller will be the static control law combined with the feedforward dynamics. A necessary and sufficient condition for the existence of the parallel feedfornward compensator (PFC) is given by the static output feedback fomulation, which enables to utilize linear matrix inequality (LMI). The effectiveness of the proposed method is illustrated by some examples including the systems which can be stabilized by the proprotional-derivative (PD) control law.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1007-1009
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• 2008

This paper presents an architecture for driving multiple paralleled cold cathode fluorescent lamps (CCFLs) for back lighting applications. The key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition. This like the EEFL it will be able to use the CCFL is the thing. Also, it investigates the effect where the leakage current goes mad to the Lamp.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.126-128
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• 2008

This paper presents an architecture for driving multiple paralleled cold cathode fluorescent lamps (CCFLs) for back lighting applications. Multi CCFL operation and increase of brightness, the key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, The capacitive coupling the leakage inductance and stray capacitance creation which it used, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition.

• Steel and Composite Structures
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• v.46 no.1
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• pp.53-73
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• 2023

Man-made structure materials like concrete usually contain inclusions. These inclusions affect the mechanical properties of concrete. In this investigation, the influence of inclusion length and inclination angle on three-dimensional failure mechanism of concrete under uniaxial compression were performed using experimental test and numerical simulation. Approach of acoustic emission were jointly used to analyze the damage and fracture process. Besides, by combining the stress-strain behavior, quantitative determination of the thresholds of crack stress were done. concrete specimens with dimensions of 120 mm × 150 mm × 100 mm were provided. One and two holes filled by gypsum are incorporated in concrete samples. To build the inclusion, firstly cylinder steel tube was pre-inserting into the concrete and removing them after the initial hardening of the specimen. Secondly, the gypsum was poured into the holes. Tensile strengths of concrete and gypsum were 2.45 MPa and 1.5 MPa, respectively. The angle bertween inclusions and axial loadind ary from 0 to 90 with increases of 30. The length of inclusion vary from 25 mm to 100 mm with increases of 25 mm. Diameter of the hole was 20 mm. Entirely 20 various models were examined under uniaxial test. Simultaneous with experimental tests, numerical simulation (Particle flow code in two dimension) were carried out on the numerical models containing the inclusions. The numerical model were calibrated firstly by experimental outputs and then failure behavior of models containing inclusions have been investigated. The angle bertween inclusions and axial loadind vary from 0 to 90 with increases of 15. The length of inclusion vary from 25 mm to 100 mm with increases of 25 mm. Entirely 32 various models were examined under uniaxial test. Loading rate was 0.05 mm/sec. The results indicated that when inclusion has occupied 100% of sample thickness, two tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. When inclusion has occupied 75% of sample thickness, four tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. When inclusions have occupied 50% and 25% of sample thickness, four tensile cracks originated from boundaries of sample and spread parallel to the loading direction until being integrated together. Also the inclusion was failed by one tensile crack. The compressive strength of samples decease with the decreases of the inclusions length, and inclusion angle had some effects on that. Failure of concrete is mostly due to the tensile crack. The behavior of crack, was affected by the inclusion length and inclusion number.

• Wind and Structures
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• v.13 no.1
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• pp.57-82
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• 2010

The 486m-long roof of Shenzhen Citizens Centre is one of the world's longest spatial lattice roof structures. A comprehensive numerical study of wind effects on the long-span structure is presented in this paper. The discretizing and synthesizing of random flow generation technique (DSRFG) recently proposed by two of the authors (Huang and Li 2008) was adopted to produce a spatially correlated turbulent inflow field for the simulation study. The distributions and characteristics of wind loads on the roof were numerically evaluated by Computational Fluid Dynamics (CFD) methods, in which Large Eddy Simulation (LES) and Reynolds Averaged Navier-Stokes Equations (RANS) Model were employed. The main objective of this study is to explore a useful approach for estimations of wind effects on complex curved roof by CFD techniques. In parallel with the numerical investigation, simultaneous pressure measurements on the entire roof were made in a boundary layer wind tunnel to determine mean, fluctuating and peak pressure coefficient distributions, and spectra, spatial correlation coefficients and probability characteristics of pressure fluctuations. Numerical results were then compared with these experimentally determined data for validating the numerical methods. The comparative study demonstrated that the LES integrated with the DSRFG technique could provide satisfactory prediction of wind effects on the long-span roof with complex shape, especially on separation zones along leading eaves where the worst negative wind-induced pressures commonly occur. The recommended LES and inflow turbulence generation technique as well as associated numerical treatments are useful for structural engineers to assess wind effects on a long-span roof at its design stage.

• Convergence Security Journal
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• v.15 no.6_1
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• pp.79-92
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• 2015

It is required to expand area of inter-Korean economic cooperation, being limited to non-military field, to military field and then, to positively promote arms control in order to establish foundation for peaceful reunification in Korean peninsula. Reasons why arms control has not been promoted between South and North Korea in the meantime were such original factors as follows; (1) limit of confidence building between the South and the North, (2) functional limit of arms control itself, (3) institutional structural limit between the South and the North, (4) environmental limit at home and abroad. It is necessary to get out from existing frame and to seek a new paradigm in order to overcome above factors and to realize arms control between the South and the North. First, it is required to have prior political dialog at the South-North high-level talks in order to promote arms control and to exercise 'strategic flexibility' during negotiation and promotion process. For this, 'flexible reciprocity' has to be adopted in compliance with situation and conditions. Second, it is necessary to get out from existing principle of 'confidence building in advance and arms reduction later' but to seek the 'simultaneous driving principle of confidence building and arms reduction' as an eclectic approach. Namely, based on reasonable sufficiency, it is required to promote military confidence building and limited arms reduction in parallel, which is a lower level of arms control. Third, as an advisory body of Prime Minister's Office, it is necessary to install an organization exclusively responsible for arms control and to positively handle arms control issue from the standpoint of national policy strategy. If the South-North high-level talks take place, it is necessary to organize and operate 'South-North Joint Arms Control Promotion Board (tentative name)'. Fourth, it is required to exercise more active diplomatic competence in order to create national consensus on necessity of arms control for peaceful reunification and to form more favorable international environment. Especially, it is necessary to think about how to solve nuclear issue of North Korea together in collaboration with international society and how to maintain balance between ROK-US alliance and Sino-Korean cooperation relations.