Yonsei University

About: Yonsei University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Cancer. The organization has 50162 authors who have published 106172 publications receiving 2279044 citations. The organization is also known as: Yonsei.

Reliability Improvement Using Receive Mode Selection in the Device-to-Device Uplink Period Underlaying Cellular Networks

Abstract: A new interference management scheme is proposed to improve the reliability of a device-to-device (D2D) communication in the uplink (UL) period without reducing the power of cellular user equipment (UE). To improve the reliability of the D2D receiver, two conventional receive techniques and one proposed method are introduced. One of the conventional methods is demodulating the desired signal first (MODE1), while the other is demodulating an interference first (MODE2), and the proposed method is exploiting a retransmission of the interference from the base station (BS) (MODE3). We derive their outage probabilities in closed forms and explain the mechanism of receive mode selection which selects the mode guaranteeing the minimum outage probability among three modes. Numerical results show that by applying the receive mode selection, the D2D receiver achieves a remarkable enhancement of outage probability in the middle interference regime from the usage of MODE3 compared to the conventional ways of using only MODE1 or MODE2.

An overview of the past, present and future of gravity-wave drag parametrization for numerical climate and weather prediction models

Abstract: An overview of the parametrization of gravity ‐wave drag in numerical ‐weather prediction and climate simulation models is presented. The focus is primarily on understanding the current status of gravity wave drag parametrization as a step towards the new parametrizations that will be needed for the next generation of atmospheric models. Both the early history and latest developments in the field are discussed. Parametrizations developed specifically for orographic and convective sources of gravity waves are described separately, as are newer parametrizations that collectively treat a spectrum of gravity wave motions. The differences in issues in and approaches for the parametrization of the lower and upper atmospheres are highlighted. Various emerging issues are also discussed, such as explicitly resolved gravity waves and gravity wave drag in models, and a range of unparametrized gravity wave processes that may need attention for the next generation of gravity wave drag parametrizations in models.

A novel timing estimation method for OFDM systems

Abstract: We present a novel timing offset estimation method for orthogonal frequency division multiplexing systems. The estimator proposed here is designed to avoid the ambiguity which occurs in Schmidl's (1997) timing offset estimation method. The performance of the proposed scheme is presented in terms of mean and mean-square error (MSE) obtained by simulations. The simulation results show that the proposed estimator has a significantly smaller MSE than the other estimators.

Dual-mode nanoparticle probes for high-performance magnetic resonance and fluorescence imaging of neuroblastoma.

Abstract: Inorganic nanoparticles are emerging as potential probes in next-generation biomedical applications. Their enhanced properties arising from nanoscale effects and their comparable size to biofunctional molecules have allowed for ultrasensitive detection of biomolecular targets. Of the various nanoparticles, quantum dots and fluorescent-dye-doped silica nanoparticles are representative examples of optical nanoprobe systems. Dye-doped silica nanoparticles have several advantages for optical imaging: 1) high photostability arising from the stabilization of dye molecules in a protective silica matrix, 2) amplification of the fluorescent signal owing to high dye-incorporation capabilities of silica nanoparticles, and 3) the silica is known to be relatively biocompatible and less toxic. On the other hand, magnetic nanoparticles exhibit a unique magnetic-resonance (MR) contrast enhancement effect that enables noninvasive MR imaging of cell trafficking, gene expression, and cancer. However, retrieving detailed biological information on a subcellular level is difficult owing to limited resolution and low sensitivity of the MRI technique. Until now, most previous studies that utilized optical and/or magnetic nanoparticle probes have been focused on monofunctional probes, except for a few primitive dual probes such as the single magnetic nanoparticle that was directly linked to organic dyes. Our strategy for the development of the next generation of nanoprobes has been to fuse multiple fluorescent dyes and multiple magnetic nanoparticles into a single nanoprobe that provides superior fluorescence and MR imaging capabilities through the synergistic enhancement of its respective components. Specifically, we have fabricated new “core–satellite” structured dual functional nanoparticles comprised of a dyedoped silica “core” and multiple “satellites” of magnetic nanoparticles. We further demonstrate their utilization as simultaneous optical and MR imaging of neuroblastoma cells expressing polysialic acids (PSAs). Detection of PSA is important as it is not only an important carbohydrate associated with neural pathways, such as synaptic plasticity, learning and memory, and cell-to-cell interaction, but it is also a marker of neuroblastoma, lung carcinoma, and Wilms7 tumors. Rhodamine-dye-doped silica (DySiO2) nanoparticles with surface amine groups were synthesized by a modified literature method. The obtained nanoparticles have a homogeneous size of 30 nm (Figure 1b). High-quality watersoluble iron oxide (Fe3O4, abbreviated as WSIO) nanoparticles were synthesized following a method previously reported by us. The WSIO nanoparticles are 9 nm in diameter with high monodispersity (s 5%) and coated with 2,3-dimercaptosuccinic acid (DMSA; Figure 1c). Our core–satellite nanoparticles were fabricated through the conjugation of these DySiO2 nanoparticles with WSIO by using sulfosuccinimidyl-(4-N-maleimidomethyl)cyclohexane1-carboxylate (sulfo-SMCC, Pierce) cross-linkers (Figure 1a). First, the amine groups of the DySiO2 nanoparticle were modified with maleimide groups by reacting them with sulfoSMCC cross-linkers. The reactions between the maleimide groups of the silica nanoparticle and the thiol groups ofWSIO nanoparticles subsequently yielded hybrid nanoparticles ((DySiO2–(Fe3O4)n, n= 10 2) of a dye-doped silica core and iron oxide satellites. [*] S.-I. Yeon, Prof. J.-S. Shin Department of Microbiology College of Medicine Yonsei University Seoul 120-752 (Korea) E-mail: jsshin6203@yumc.yonsei.ac.kr