• Journal of Korean Society of Steel Construction
• /
• v.16 no.4 s.71
• /
• pp.425-432
• /
• 2004

Large studs were suggested not only for the design of steel-concrete composite bridges with simplified sections but also for the shear connection in precast decks requiring uniform distribution of shear pockets. Based on the push-out test results on studs with diameters of more than 25 mm, partial composite beams with 40%-degree shear connection were fabricated, and static tests were performed. The ultimate strength and horizontal shear load redistribution of partial composite beams, which have parameters of stud shank diameters and distribution, were evaluated, and group failure in the shear span was observed. Since the flexural strength of composite beams are dependent on the strength of their shear connection, the strength of the stud connection was estimated and it showed considerably higher shear strength. From the load-slip curves, the sufficient ductility and load redistribution of large studs were confirmed. Uniformly distributed large studs can provide proper ultimate behavior of composite beams.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.12
• /
• pp.2805-2812
• /
• 2015

For the purpose of estimation of time variant frequency selective transmission channels, reference symbols are usually employed. The bit error performance of LTE OFDM systems is analyzed in the case of LTE standard reference symbol arrangement. Results show that LTE OFDM system with this LTE reference symbol arrangement is robust against Doppler time variant fading. However, the performance of that system is degraded due to channel estimation error in frequency domain. An equidistant arrangement with a diamond shape structure of reference symbols, however having 4 subcarriers distance in frequency domain, is suggested for the optimal channel estimation.

• Land and Housing Review
• /
• v.2 no.1
• /
• pp.79-85
• /
• 2011

The bearing capacity of a soil can be improved by conventional ground improvement techniques such as stabilization and compaction methods. Recently, the use of geotextiles in improving the bearing capacity of soils has become popular because of the availability of durable and strong geosynthetic materials. In this paper, through the laboratory model tests on sandy ground reinforced by geotextiles with the strip footing under plane strain condition, the effects of bearing capacity improvement on the sandy ground and its behaviour were investigated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.3
• /
• pp.57-65
• /
• 2005

No matter how well the equally spaced grounding grid is designed, there we questions keep rising, such as leakage of current from comer conductor, high voltage of touch voltage in comers of grid than in center, and high material cost for grounding grid. The best-fitted design for unequally spaced grounding grid is a part that must be considered. Explain advantages of unequally spaced grounding grid and lead formula by dividing the number of grid division, j, into 20, instead of 7. Then, present Dij, which is optimum rate for unequally spaced grounding grid and verify safety and economy of the unequally spaced grounding grid by computer simulation with a poly-nominal function form.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.11
• /
• pp.891-897
• /
• 2018

In this paper, we propose a blind estimation scheme for the antenna spacing of nonuniform linear array MIMO radar using distributed electronic sensors based on ESPRIT. We present a blind method to separate orthogonal waveforms of a MIMO radar based on the antenna spacing estimation. The estimated orthogonal waveforms of a MIMO radar can be used for disabling opponent MIMO radars.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.2
• /
• pp.121-129
• /
• 2002

The present paper describes a technique for installing an effective grounding grids, the major objective is forced on the experimental evaluation of the performance and characteristics with the arrangement and installation method for grounding grids consisting of the means to protect electric shock, electronics and computerized facilities against lightning, switching and ground fault surges. The study is oriented on two major areas: (1) the analysis of the ground surface potential gradient with the arrangement of grounding grids, (2) the control of the dangerous ground surface potential rise. The experiments wee carried out with the impulse currents as a function of the installation method or arrangement of grounding grids. An installation method of the inclined auxiliary grounding grid was proposed to overcome the drawbacks of equally spared grounding grids, i.e. an appropriate design concept far the installation of grounding grids was found out, It has been shown that the installation of the intwined auxiliary grounding grid can also result in a mere than 50% decrease in the maximum potential gradient on the ground surface and enhance the level of safety for persons and electronic equipments..

• Journal of the Korea Computer Graphics Society
• /
• v.25 no.3
• /
• pp.143-152
• /
• 2019

This paper presents two new techniques for solving the two problems of the water curtain: 'shape distortion' caused by gravity and 'resolution degradation' caused by fine satellite droplets around the shape. In the first method, when the user converts a three-dimensional model to a vertical sequence of slices, the slices are evenly spaced. The method is to adjust the time points at which the equi-distance slices are created by the nozzle array. In this method, even if the velocity of a water drop increases with time by gravity, the water drop slices maintain the equal interval at the moment of forming the whole shape, thereby preventing distortion. The second method is called the minimum time interval technique. The minimum time interval is the time between the open command of a nozzle and the next open command of the nozzle, so that consecutive water drops are clearly created without satellite drops. When the user converts a three-dimensional model to a sequence of slices, the slices are defined as close as possible, not evenly spaced, considering the minimum time interval of consecutive drops. The slices are arranged in short intervals in the top area of the shape, and the slices are arranged in long intervals in the bottom area of the shape. The minimum time interval is pre-determined by an experiment, and consists of the time from the open command of the nozzle to the time at which the nozzle is fully open, and the time in which the fully open state is maintained, and the time from the close command to the time at which the nozzle is fully closed. The second method produces water drop sculptures with higher resolution than does the first method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.6
• /
• pp.60-66
• /
• 2010

Mesh grounding electrodes in Korea and abroad are designed as lattice-shaped equidistance grounding grids. In case of a lattice-shaped grounding Grid, however, there is a problem of higher touch voltage at the corner of the grid relative to the center. To overcome this problem, we used oblique-shaped equidistance grounding grid to reduce the area of the corner where mesh voltage occurs. As a result the mesh voltage was reduced. Therefore, this paper suggests the use of oblique-shaped grounding grid instead of the existing lattice-shaped ones. It applied the same grounding design dimensions for both lattice-shaped and oblique-shaped grounding grids, compared and analyzed mesh voltage, GPR, ground resistance, total length of grounding conductor, verified that oblique-shaped grounding grid is superior to the lattice-shaped.