• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1998-2004
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• 2019

The Multi-Physics (MP) instrument is one of 20 neutron spectrometers planned in the China Spallation Neutron Source (CSNS). This paper presents a shielding calculation for the MP instrument using Monte Carlo codes MCNPX and FLUKA. First, the neutrons that escape from the CSNS decoupled water moderator and are delivered to the beam line of the MP instrument are calculated to use as the source term of the shielding calculation. Then, to validate the calculation method based on multiple variance reduction techniques, a cross check between MCNPX and FLUKA codes is performed by comparing the calculation results of the dose rate distribution on a simplified beam line model. Finally, a complete geometry model of the MP instrument is set up, and the primary parameters for the shielding design are obtained according to the calculated dose rate map considering different worst-case scenarios.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.257-265
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• 2004

The aim of this study is to investigate the inelastic buckling behavior of the beams under moment gradient using a line-type finite element method. The method is incorporated the non-uniform yielding of the cross-section caused by the presence of residual stress and accepted model of residual stress so called 'simplified' and 'polynomial' pattern is adopted in this study. The inelastic lateral-torsional buckling results obtained in this study is compared with the buckling results obtained from the design method based on the allowable stress method given in Korean Steel Designers Manual (KSDM 1995). This study have found that the design method in KSDM (1995) is conservative without and with intermediate bracing applied at the mid span of the beam, and there is some scope for improving the provisions of KSDM (1995)

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.200-205
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• 2014

In this paper, 5.8GHz band $4{\times}4$ Butler matrix is designed using easily accessible commercial $90^{\circ}$ hybrid coupler and semirigid coaxial cable as a transmission line. This Butler matrix is very flexible to changes of antenna system specification like a frequency band because $90^{\circ}$ hybrid coupler changing is all to do. The result of design is the distance of $2{\times}2$ array antenna element is $\sqrt{2}{\lambda}/4$, the 4 beam directions are diagonal of array antenna and phase shifter is not necessary. The beam width is roughly $25^{\circ}$ narrower because of array antenna geometry and the side lobe is about 10dB higher partially than theoretical beam pattern. But the overall beam pattern is similar with theoretical beam. This Butler matrix can be applied to switching beam antenna of 5.8GHz band Wi-Fi and WAVE system.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.17-22
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• 2008

Construction project have extremely high risk in the process of construction owing to unexpected event, like as design amendment. As a result, owner have to endure enormous extra-cost to control the risk and continue to the project having more higher uncertainty. Also, if the structure is completed, it is needed that the structure is protected and maintained continuously during life cycle time to satisfying original aim of structure itself. LCC analysis to calculate cost of structure alternatives divides into two stage, one is design_LCC and the other is maintenace_LCC. But two stages all is needed in the transition deterioration model to calculate more reasonable LCC analysis. This paper developed the model using analysis of FMS contents and survey from professional about Prestressed concrete beam girder bridge(PC Beam bridge)in railway. The model is focused in project level of PC beam because any condition state information for element level analysis can not get up. This paper is intended to use the developed model in LCC analysis of PC Beam bridge in railway and constitute the foundation to perform more deep study in the near future.

• 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.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1174-1187
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• 2007

Monorail System has many advantages compared with other Urban Lightweight Transit Systems, such as the friendliness of the vehicle's appearance, slenderness of the bridge structures, it's low construction cost and short construction period. So, lots of city governments have reviewed or proposed the Monorail System as the attractive alternative system. And recently, Daegu Metropolitan City Government have chosen the Monorail System for the Urban Railroad Line 3. According to these trends on Urban Lightweight Transit Systems, this paper has introduced the outline of the planning and design of Monorail Bridges. At first, trends of overseas Monorail Bridges have been reviewed and the principal design criteria adopted in the basic design of the Urban Railroad Line 3 for Daegu have been introduced. And next, the methods of planning, design, fabrication of the guideway beams which are made of PSC Beam or Steel Beam have been explained. We hope this paper be helpful for the Engineers who are interested in the Monorail Bridges.

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.295-303
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• 2017

In this paper, we have studied a method of forming a line beam using a UV LED. The existing linear-type UV LED curing optical system is composed of several cylindrical lenses, but problems such as optical system alignment, enlargement of the module, efficiency, etc. may arise in the future. As an alternative to these problems, a bar-type TIR lens having a freeform surface only in the y-axis direction is designed, to verify that it shows advantages in maximum illuminance, uniformity of illuminance, and flux efficiency.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.320-328
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• 2011

The down town passage segment which follows in the straight line which follows recently in high speed of the railway and rail construction is increasing. Also according to quality of life improvement of the citizens whom follows in national income increase the resident demand only becomes larger day by day about a environmental creation which is comfortable and house environmental etc. Demand of the citizens is not the problem of today yesterday about like this railway mean of transportation and with the fact that continuously will increase in future. This study is to predict and reduce railway noise from the conventional PSC-beam bridges which passes through urban areas under the government strateges of speed and weight increases of railway. The purpose of this study is to recommend a proper noise prediction method for designing pleasant roadside environments. The railway design including existing line reconstructions should minimize curved alignment to increase train speed to 180~200km/hr under the government's long-term planing such as the 4th Comprehensive National Development Plan (2000~2020), National Intermodal Transportation Plan (2000~2019) and National Railroad Network Establishment Plan (2006~2015), Since the PSC-beam bridges are mainly used for bridge structures urban areas, noise measurements were performed and analyzed to recommend the noise prediction methods for each type and speed of train respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.155-160
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• 2024

The polarization-selective beam splitter grating can be widely used in numerous optical information processing systems. In this paper, to design a high-efficiency plasma polarization beam splitter (PBS), the structure composed of an Ag metal layer in Littrow mounting is implemented. To achieve high diffraction efficiency in the transmitted 0th-order TE polarization and the reflected 0th-order TM polarization, the grating depth and grating ratio of presented PBS is optimized by using rigorous Modal Transmission-Line Theory. From the optimized results, PBS has advantages of wide band properties for incident wavelength and angle, and the efficiency is higher than 95% for both TE and TM polarization. Therefore, this highly efficient PBS wideband grating with high extinction ratio can be used as an excellent optical diffraction device.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.4
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• pp.50-55
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• 2007

Stereolithography (SLA) is a technique using a laser beam to cure a photopolymer liquid resin with three-dimensional computer-aided design (CAD) data, The accuracy of the prototype, the build time, and the cured properties of the resins are controlled by the SLA process parameters such as the size of the laser beam, scan velocity, hatch spacing, and layer thickness, In particular, the size of the laser beam is the most important parameter in SLA, This study investigated the curing properties of photopolymers as a function of the laser beam size, The cure width and depth were measured either on a single cure line or at a single cure layer for various hatch spacings and laser beam sizes, The cure depth ranged from 0.23 to 0.34 mm and was directly proportional to the beam radius, whereas the cure width ranged from 0.42 to 1.07 mm and was inversely proportional to the beam radius, The resulting surface roughness ranged from 1.12 to $2.23{\mu}m$ for a ratio of hatch spacing to beam radius in the range 0.5-2.0 at a beam radius of 0.17 mm and a scan velocity of 125 mm/sec.