• Korean Journal of Geomatics
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• v.1 no.1
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• pp.69-74
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• 2001

In conventional photogrammetry, three-dimensional coordinates are obtained from two consecutive images of a stationary object photographed from two exposure stations, separated by a certain distance. However, it is impossible to photograph moving objects from two stations with one camera at the same time. Various methods to overcome this obstacle were devised e. g. taking the left and right scenes simultaneously with one camera using a beam splitter attached to the front, thus creating a stereo scene in one image. A beam splitter consists of two outer mirrors and two inner mirrors. This paper deals with research where the optical principles of the beam splitter were evaluated based on light path phenomena between the outer mirrors and the inner mirrors. A mathematical model of the geometric configuration was derived for the beam splitter. This allows us to design and control a beam splitter to obtain maximum scale and maximum base-height ratio by stepwise application of the mathematical model. The results show that the beam splitter is a very useful tool for stereophotography with one camera. The optimum geometric configurations ensuring maximum scale and base-height ratio are closely related to inner and outer reflector sizes, their inclination angles and the offsets between the outer mirrors.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4310-4321
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• 2022

The concept of dense granular-flow target (DGT) for the China Initiative Accelerator Driven Subcritical system (CiADS) is an attractive choice for high heat removal ability, low chemical toxicity, and radiotoxicity. A wobbling hollow beam is proposed to enhance the homogeneity of temperature rise of flowing particles in beam-target coupling zone. In this paper, the design procedure of target and beam parameters was discussed firstly. Then we simulated the heat deposition and transfer of the scanning beam in DGT to study the effect of beam parameters. The results show the flux density of proton beam plays a crucial role in the distribution of temperature rise while the contributions from scanning frequency heat transfer are also obvious. Moreover, heat transfer in transversal directions is insignificant, resulting in a low heat flux towards the sidewalls of DGT. This work not only contributes to the design of DGT, but also beneficial for understanding the beam-target coupling in porous materials.

• Steel and Composite Structures
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• v.45 no.1
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• pp.101-118
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• 2022

The seismic performance of the reinforced concrete (RC) special-shaped column to steel beam connections with steel jacket used in the RC column to steel beam fabricated frame structures was investigated in this study. The three full-scale specimens were subjected to cyclic loading. The failure mode, ultimate bearing capacity, shear strength capacity, stiffness degradation, energy dissipation capacity, and strain distribution of the specimens were studied by varying the steel jacket thickness parameters. Test results indicate that the RC special-shaped column to steel beam connection with steel jacket is reliable and has excellent seismic performance. The hysteresis curve is full and has excellent energy dissipation capacity. The thickness of the steel jacket is an important parameter affecting the seismic performance of the proposed connections, and the shear strength capacity, ductility, and initial stiffness of the specimens improve with the increase in the thickness of the steel jacket. The calculation formula for the shear strength capacity of RC special-shaped column to steel beam connections with steel jacket is proposed on the basis of the experimental results and numerical simulation analysis. The theoretical values of the formula are in good agreement with the experimental values.

• Structural Engineering and Mechanics
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• v.57 no.6
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• pp.989-1014
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• 2016

This paper deals with the analysis of the natural frequencies, mode shapes of an axially loaded beam system carrying ends consisting of non-concentrated tip masses and three spring-two mass sub-systems. The influence of system design and sub-system parameters on the combined system characteristics is the major part of this investigation. The effect of material properties, rotary inertia and shear deformation of the beam system is included. The end masses are elastically supported against rotation and translation at an offset point from the point of attachment. Sub-systems are attached to center of gravity eccentric points out of the beam span. The boundary conditions of the ordinary differential equation governing the lateral deflections and slope due to bending of the beam system including developed shear force frequency dependent terms, due to the sub.system suspension, have been formulated. Exact formulae for the modal frequencies and the modal shapes have been derived. Based on these formulae, detailed parametric studies are carried out. The geometrical and mechanical parameters of the system under study have been presented in non-dimensional analysis. The applied mathematical model is presented to cover wide range of mechanical, naval and structural engineering applications.

• Steel and Composite Structures
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• v.45 no.2
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• pp.231-248
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• 2022

Hybrid Steel-Trussed Concrete Beam (HSTCB) is structural typology suitable for light industrialization. HSTCBs usually cover long span with small depths, which lead to significant amount of longitudinal rebars. The latter make beam-column joints more prone to damage due to earthquake-induced cyclic actions. This phenomenon can be avoided using friction-based BCCs. Friction devices at Beam-to-Column Connections (BCCs) have become promising solutions to reduce the damage experienced by structural members during severe earthquakes. Few solutions have been developed for cast-in-place Reinforced Concrete (RC) and steel-concrete composite Moment Resisting Frames (MRFs), because of the difficulty of designing cost-effective damage-proof connections. This paper proposes a friction-based BCC for RC MRFs made with HSTCBs. Firstly, the proposed connection is described, and its innovative characteristics are emphasized. Secondly, the design method of the connection is outlined. A detailed 3D FE model representative of a beam-column joint fitted with the proposed connection is developed. Several monotonic and cyclic analyses are performed, investigating different design moment values. Lastly, the numerical results are discussed, which demonstrate the efficiency of the proposed solution in preventing damage to RC members, and in ensuring satisfactory dissipative capacity.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2064-2071
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• 2020

For proton pencil beam scanning (PBS) technology, the accuracy of the dose distribution in a patient is sensitive to the properties of the incident beam. However, mechanical deformation of the proton therapy facility may occur, and this could be an important factor affecting the proton dose distribution in patients. In this paper, we investigated the effect of deformation on an SC200 proton facility's beam isocenter properties. First, mechanical deformation of the PBS nozzle, L-shape plate, and gantry were simulated using a Finite Element code, ANSYS. Then, the impact of the mechanical deformation on the beam's isocenter properties was evaluated using empirical formulas. In addition, we considered the simplest case that could affect the properties of the incident beam (i.e. if only the bending magnet (BG3) has an error in its mounting alignment), and the effect of the beam optics offset on the isocenter characteristics was evaluated. The results showed that the deformation of the beam position in the X and Y direction was less than 0.27 mm, which meets the structural design requirements. Compared to the mechanical deformation of the L-shape plate, the deformation of the gantry had more influence on the beam's isocenter properties. When the error in the mounting alignment of the BG3 is equal to or more than 0.3 mm, the beam deformation at the isocenter exceeds the maximum accepted deformation limits. Generally speaking, for the current design of the SC200 scanning beam delivery system, the effects of mechanical deformation meet the maximum accepted beam deformation limits. In order to further study the effect of the incident beam optics on the isocenter properties, a fine-scale Monte Carlo model including factors relating to the PBS nozzle and the BG3 should be developed in future research.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.245-250
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• 1999

In this study, the development of graphic user interface(GUI) program for optimum design of RC continuous beam is dealt. Optimum design problem that satisfies strength, serviceability, durability and geometrical conditions is formulated as a non-linear programming problem(NLP) in which the objective function as well as the constraints are highly non-linear on design variables such as cross sectional dimensions and steel ratio. Optimum design problem is solved by NLP techniques namely, sequential linear programming(SLP), sequential convex programming(SCP). Numerical examples of R.C. continuous beam using GUI system are given to show usefulness of GUI system for practical design work and efficiency of algorithm for the NLP techniques.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.329-330
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• 2009

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.391-398
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• 2009

In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of hierarchical fair competition-based genetic algorithm(HFCGA) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. The displacement change the position of ball leads to the change of the angle of the beam which determines the position angle of a servo motor. Consequently the displacement change of the position of the moving ball and its ensuing change of the angle of the beam results in the change of the position angle of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling factors) of each fuzzy controller using HFCGA. The inner controller controls the position of lever arm which corresponds to the position angle of a servo motor and the outer controller decides the set-point value of the inner controller. HFCGA is a kind of parallel genetic algorithms(PGAs), and helps alleviate the premature convergence being generated in conventional genetic algorithms (GAs). For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on HFCGA, is presented in comparison with the conventional PD cascade controller based on serial genetic algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2038-2043
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• 2009

This study investigates elastic lateral-torsional buckling(LTB) of T-beams subjected to pure bending using finite element analysis(FEA). The results from the FEA are compared with those from the current American Institute of Steel Council(AISC) Load and Resistance Factor Design(LRFD) Specifications. The comparison indicates that AISC-LRFD provide unsafe values for T-beam subjected to pure bending. Therefore, a new design equation are presented using results from the FEA. The new equation could be easily used to calculate the elastic lateral-torsional buckling moment resistance of T-beam for beam design and to expand the new equation for developing LTB equations of T-beam subjected to general loading conditions such as a concentrated load, distributed load, or a seres of concentrated load.