Sungkyunkwan University

About: Sungkyunkwan University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Thin film & Graphene. The organization has 28229 authors who have published 56428 publications receiving 1352733 citations. The organization is also known as: 성균관대학교.

Learning by reviewing.

Abstract: Peer review of writing provides an alternative to the traditional approach of practicing writing with feedback from an instructor. Most of the limited research on peer review has examined the general effects or focused on the effects of receiving feedback from peers. The current study focused on the effects of giving feedback, that is, on whether students learn to write better by reviewing peer writing. Sixty-one undergraduate students were randomly assigned to reviewing, reading, or no-treatment control conditions. Reviewers rated and commented on papers written by peers. Readers read the same papers without commenting. All students then wrote a paper in the same genre but on a different topic. Students in the reviewing condition significantly outperformed those in both other conditions on the quality of the report. Follow-up analysis indicated that comments coded as "problem detection" and "solution suggestion" were positively correlated with writing outcomes for students in the reviewing condition. This research provides support for the use of peer review of writing as a learning activity

Ambient Backscatter: A New Approach to Improve Network Performance for RF-Powered Cognitive Radio Networks

Abstract: This paper introduces a new solution to improve the performance for secondary systems in radio frequency (RF) powered cognitive radio networks (CRNs) In a conventional RF-powered CRN, the secondary system works based on the harvest-then-transmit protocol That is, the secondary transmitter (ST) harvests energy from primary signals and then uses the harvested energy to transmit data to its secondary receiver (SR) However, with this protocol, the performance of the secondary system is much dependent on the amount of harvested energy as well as the primary channel activity, eg, idle and busy periods Recently, ambient backscatter communication has been introduced, which enables the ST to transmit data to the SR by backscattering ambient signals Therefore, it is potential to be adopted in the RF-powered CRN We investigate the performance of RF-powered CRNs with ambient backscatter communication over two scenarios, ie, overlay and underlay CRNs For each scenario, we formulate and solve the optimization problem to maximize the overall transmission rate of the secondary system Numerical results show that by incorporating such two techniques, the performance of the secondary system can be improved significantly compared with the case when the ST performs either harvest-then-transmit or ambient backscatter technique

Single-step solvothermal synthesis of mesoporous Ag–TiO2–reduced graphene oxide ternary composites with enhanced photocatalytic activity

Abstract: With growing interest in the photocatalytic performance of TiO2-graphene composite systems, the ternary phase of TiO2, graphene, and Ag is expected to exhibit improved photocatalytic characteristics because of the improved recombination rate of photogenerated charge carriers and potential contribution of the generation of localized surface plasmon resonance at Ag sites on a surface of the TiO2-graphene binary matrix. In this work, Ag-TiO2-reduced graphene oxide ternary nanocomposites were successfully synthesized by a simple solvothermal process. In a single-step synthetic procedure, the reduction of AgNO3 and graphene oxide and the hydrolysis of titanium tetraisopropoxide were spontaneously performed in a mixed solvent system of ethylene glycol, N,N-dimethylformamide and a stoichiometric amount of water without resorting to the use of typical reducing agents. The nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, along with different microscopic and spectroscopic techniques, enabling us to confirm the successful reduction of AgNO3 and graphite oxide to metallic Ag and reduced graphene oxide, respectively. Due to the highly facilitated electron transport of well distributed Ag nanoparticles, the synthesized ternary nanocomposite showed enhanced photocatalytic activity for degradation of rhodamine B dye under visible light irradiation.

Interference management in LTE femtocell systems using Fractional Frequency Reuse

Abstract: Recently, Long Term Evolution (LTE) has developed a femtocell for indoor coverage extension. However, interference problem between the femtocell and the macrocell should be solved in advance. In this paper, we propose an interference management scheme in the LTE femtocell systems using Fractional Frequency Reuse (FFR). Under the macrocell allocating frequency band by the FFR, the femtocell chooses sub-bands which are not used in the macrocell sub-area to avoid interference. Simulation results show that proposed scheme enhances total/edge throughputs and reduces the outage probability in overall network, especially for the cell edge users.

A Benzobisimidazolium-Based Fluorescent and Colorimetric Chemosensor for CO2

Abstract: A new sensor for the fluorescent and colorimetric detection of CO2 is described. The system utilizes fluoride to activate a tetrapropyl benzobisimidazolium salt and operates in the absence of an exogenous base. On the basis of spectroscopic and theoretical analyses, the mode of action of the present system is ascribed to the fluoride-induced formation of an N-heterocyclic carbene intermediate that reacts with CO2 to form an imidazolium carboxylate.