Chung-Ang University

About: Chung-Ang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 13381 authors who have published 26978 publications receiving 416735 citations. The organization is also known as: CAU & Chung.

Intelligent Reflecting Surface-Assisted Cognitive Radio System

Abstract: Cognitive radio (CR) is an effective solution to improve the spectral efficiency (SE) of wireless communications by allowing the secondary users (SUs) to share spectrum with primary users (PUs). Meanwhile, intelligent reflecting surface (IRS), also known as reconfigurable intelligent surface (RIS), has been recently proposed as a promising approach to enhance energy efficiency (EE) of wireless communication systems through intelligently reconfiguring the channel environment. To improve both SE and EE, in this paper, we introduce multiple IRSs to a downlink multiple-input single-output (MISO) CR system, in which a single SU coexists with a primary network with multiple PU receivers (PU-RXs). Our design objective is to maximize the achievable rate of SU subject to a total transmit power constraint on the SU transmitter (SU-TX) and interference temperature constraints on the PU-RXs, by jointly optimizing the beamforming at SU-TX and the reflecting coefficients at each IRS. Both perfect and imperfect channel state information (CSI) cases are considered in the optimization. Numerical results demonstrate that IRS can significantly improve the achievable rate of SU under both perfect and imperfect CSI cases.

Visible Korean Human: Improved serially sectioned images of the entire body

Abstract: The data from the Visible Human Project (VHP) and the Chinese Visible Human (CVH), which are the serially sectioned images of the entire cadaver, are being used to produce three-dimensional (3-D) images and software. The purpose of our research, the Visible Korean Human (VKH), is to produce an enhanced version of the serially sectioned images of an entire cadaver that can be used to upgrade the 3-D images and software. These improvements are achieved without drastically changing the methods developed for the VHP and CVH; thus, a complementary solution was found. A Korean male cadaver was chosen without anything perfused into the cadaver; the entire body was magnetic resonance (MR) and computed tomography (CT) scanned at 1.0-mm intervals to produce MR and CT images. After scanning, entire body of the cadaver was embedded and serially sectioned at 0.2-mm intervals; each sectioned surface was inputted into a personal computer to produce anatomical images (pixel size: 0.2 mm) without any missing images. Eleven anatomical organs in the anatomical images were segmented to produce segmented images. The anatomical and segmented images were stacked and reconstructed to produce 3-D images. The VKH is an ongoing research; we will produce a female version of the VKH and provide more detailed segmented images. The data from the VHP, CVH, and VKH will provide valuable resources to the medical image library of 3-D images and software in the field of medical education and clinical trials.

Organic–Inorganic Hybrid Halide Perovskites for Memories, Transistors, and Artificial Synapses

Abstract: Fascinating characteristics of halide perovskites (HPs), which cannot be seen in conventional semiconductors and metal oxides, have boosted the application of HPs in electronic devices beyond optoelectronics such as solar cells, photodetectors, and light-emitting diodes. Here, recent advances in HP-based memory and logic devices such as resistive-switching memories (i.e., resistive random access memory (RRAM) or memristors), transistors, and artificial synapses are reviewed, focusing on inherently exotic properties of HPs: i) tunable bandgap, ii) facile majority carrier control, iii) fast ion migration, and iv) superflexibility. Various fabrication techniques of HP thin films from solution-based methods to vacuum processes are introduced. Up-to-date work in the field, emphasizing the compositional flexibility of HPs, suggest that HPs are promising candidates for next-generation electronic devices. Taking advantages of their unique electrical properties, low-cost and low-temperature synthesis, and compositional and mechanical flexibility, HPs have enormous potential to provide a new platform for future electronic devices and explosively intensive studies will pave the way in finding new HP materials beyond conventional silicon-based semiconductors to keep up with "More-than-Moore" times.