The Korea National University of Transportation is a public, national university in Chungju City, North Chungcheong province, South Korea. The university was established in 2012 by merging Chungju National University and Korea National Railroad College. It enrolls about 200 graduate and 8,000 undergraduate students, and employs about 295 professors. The president of the University is Dr. Kim Yeong Ho. Wikipedia.
Kim H.-C.,Korea National University of Transportation
Physical Review D - Particles, Fields, Gravitation and Cosmology
We study phenomena happening at the surface of a star in Eddington-inspired Born-Infeld (EiBI) gravity. The star is made of particles, which are effectively described by a polytropic fluid. The EiBI theory was known to have a pathology that singularities happen at a star surface. We suggest that the gravitational backreaction on the particles cures the problem. Strong tidal forces near the (surface) singularity modify the effective equation of state of the particles or make the surface be unstable depending on its matter contents. The geodesic deviation equations take after Hooke's law, where its frequency squared is proportional to the scalar curvature at the surface. For a positive curvature, a particle collides with a probing wall more often and increases the pressure. With the increased pressure, the surface is no longer singular. For a negative curvature, the matters around the surface experience repulsions with infinite accelerations. Therefore, the EiBI gravity is saved from the pathology of a surface singularity. © 2014 American Physical Society. Source
Samsung and Korea National University of Transportation | Date: 2014-04-17
The present invention proposes an apparatus and a method capable of forming M*N number of beams by a base station, which supports signal transmission/reception of the macro service area in heterogeneous networks in which a macro service area is formed with the M*N number of beams through a two-dimensional arrangement simultaneously considering the horizontal dimension and the vertical dimension and at least one small service is formed in the macro service area. To this end, at least one interference prediction beam formed to transmit signals interfering in transmission signals in at least one small service area from among the signals to be transmitted by the M*N number of beams is selected, and each of the M*N number of beams is formed in consideration of the inter-cell interference in at least one small service area due to the signals to be transmitted by at least one selected interference prediction beam.
Method And Device For Transmitting Channel State Information Reference Signal, Hybrid Spatial Division Multiplexing, And Space Division Multiple Access In Wireless Communication System Using Two-Dimensional Planar Array Antenna
Samsung and Korea National University of Transportation | Date: 2014-01-15
The present invention proposes a hybrid spatial multiplexing (SM) and a space division multiple access (SDMA) technique in a frequency division duplex (FDD) massive multiple-input multiple output (MIMO) system using a two-dimensional planar array antenna, which effectively transmits a channel state information reference signal (CSI-RS) for estimating a downlink two-dimensional space channel using only a limited amount of downlink radio resources, and optimally selects and performs the SM and SDMA techniques in a two-dimensional space channel. To this end, the present invention proposes a technique which defines space resource blocks (SRB) by grouping space elements (SE) having a high spatial correlation between downlink channels in the horizontal dimension and corresponding SEs thereof in the vertical dimension, and transmits CSI-RSs for estimating channels in vertical dimension SEs corresponding to one selected horizontal SE in each SRB every transmit time interval (TTI). The present invention proposes a technique wherein user equipment (UE) estimates the spatial correlation between channels of different horizontal dimension SEs belonging to the same SRB received in different TTIs and the spatial correlation between channels of horizontal dimension SEs belonging to different SRBs received in the same TTI, and feeds information for changing the size of SRB of the corresponding UE to an optimal size back to eNodeB. The present invention proposes a technique wherein the UE estimates downlink channels through CSI-RSs transmitted from each SRB, and each UE feeds an index of a preferred SRB, a rank of the corresponding SRB in the vertical dimension, and channel quality information (CQI) back to eNodeB. When each UE determines the rank, it is possible to transmit the ranks to the fullest extent in the vertical dimension and only a single rank from each SRB in the horizontal dimension.
Korea National University of Transportation | Date: 2014-04-29
The present invention relates to optical wave guide having multiple independent optical path and optical gas sensor using that, having an effect of improving optical efficiency by elongating optical path and condensing incident light without a separate artificial structure, by using first focus points of multiple 3 dimensional elliptical mirrors as a common focus point and equipping a light source at a first focus point and optical sensor parts at each second focus points in an optical structure using multiple 3 dimensional elliptical mirrors, and by placing so that virtual lines of first elliptical mirror and second elliptical mirror form a constant angle for improving optical efficiency in a structure equipping a light source at a second focus point of any one of elliptical mirror of multiple 3 dimensional elliptical mirrors and optical sensor parts at each second focus points of another 3 dimensional elliptical mirror.
Korea National University of Transportation, Electronics and Telecommunications Research Institute | Date: 2012-06-27
A wireless communication method and apparatus using adaptive transmission polarization control are provided. The wireless communication apparatus includes an orthogonal polarization antenna, a channel state estimator, and a transmission polarization state (TPS) selector. The orthogonal polarization antenna receives at least one reference signal. The channel state estimator estimates a wireless polarization channel on the basis of the reference signal. The TPS selector selects a TPS corresponding to the estimated wireless polarization channel from among a plurality of predefined TPSs, and feeds back the selected TPS information. Accordingly, the wireless communication apparatus feeds back information for polarization control using minimum uplink wireless resources, and maximizes a transmission capacity on the basis of the feedback information.