김규홍 교수

Minimum variance (MV) beamforming has been studied for improving the performance of a diagnostic ultrasound imaging system. However, it is not easy for the MV beamforming to be implemented in a real-time ultrasound imaging system because of the enormous amount of computation time associated with the covariance matrix inversion. In this paper, to address this problem, we propose a new fast MV beamforming method that almost optimally approximates the MV beamforming while reducing the computational

Functional recovery was more likely to be achieved in patients who were under 40 years of age, victims of motor vehicle collision and having preoperative reactive pupils, higher GCS score and the absence of ABS during surgery. These results would be helpful for neurosurgeon to improve outcomes from traumatic acute subdural hematomas.

The predictors of mortality and functional recovery after PICH identified during this analysis may assist during clinical decision-making, when advising patients or family members about the prognosis of PICH and when planning intervention trials.

The aerodynamic properties of a pantograph that is under consideration for application on Korean high-speed trains are experimentally investigated. The selected experimental models were one-quarter scale pantographs (a double-arm pantograph, single-arm pantograph and a periscope pantograph) with either a rectangular panhead or a panhead with an optimized streamlined shape. To increase the performance and the robustness of the pantograph, the drag coefficient and the fluctuation of the lift coeff

The existing computer code ARCFLO, which calculates the flow through the constricted-arc heater, is modified and expanded by the use of the modern computational fluid dynamics technique. The entire flowfield within an arc-heated wind tunnel, that is, from the upstream electrode chamber to the nozzle exit, is described by the Navier-Stokes equations, but the joule heating and radiative transfer phenomena are described as in the ARCFLO code. The modeling of turbulence in the constrictor region is

There have been concerns about how far we can extend the so far so successful conventional semiconductor memories Such as DRAM, SRAM and Flash memory and what will be the future directions of memory development. In this article, we will review the key technical limits of conventional memory scaling and the directions to overcome the problem. In addition, we will review the technical challenges and opportunities of emerging. new memories such as ferroelectric RAM (FRAM), magnetic RAM (MRAM) and p

A horizontal-axis wind turbine blade is designed using two step optimization procedures with probability approach. For the efficient management of the multiple design variables required for the blade design, the design procedure is divided into two optimization steps. In step 1, the diameter and rotating speed of a blade are determined and design points are extracted from the design space. In step 2-1, blade shapes are optimized by using the strip theory with the minimum energy loss method. The