Interference Alignment Through User Cooperation for Two-cell MIMO Interfering Broadcast Channels

This paper focuses on two-cell multiple-input multiple-output (MIMO) Gaussian interfering broadcast channels (MIMO-IFBC) with $K$ cooperating users on the cell-boundary of each BS. It corresponds to a downlink scenario for cellular networks with two base stations (BSs), and $K$ users equipped with Wi-Fi interfaces enabling to cooperate among users on a peer-to-peer basis. In this scenario, we propose a novel interference alignment (IA) technique exploiting user cooperation. Our proposed algorithm obtains the achievable degrees of freedom (DoF) of 2K when each BS and user have $M=K+1$ transmit antennas and $N=K$ receive antennas, respectively. Furthermore, the algorithm requires only a small amount of channel feedback information with the aid of the user cooperation channels. The simulations demonstrate that not only are the analytical results valid, but the achievable DoF of our proposed algorithm also outperforms those of conventional techniques.Comment: This paper will appear in IEEE GLOBECOM 201

Topology Optimization to Reduce Electromagnetic Force Induced Vibration for the Specific Frequency of PMSM Motor Using Electromagnetic-Structural Coupled Analysis

Vibration and noise reduction are very important in electric vehicle driving motors. In this study, topology optimization of housing was performed to reduce vibration in a specific frequency caused by electromagnetic force generated by a permanent magnet synchronous motor (PMSM). The vibration induced by the electromagnetic force of the motor was calculated using electromagnetic-structural coupled analysis. Then, the magnitude of the acceleration for a specific frequency at which peak occurs in the rectangular and circular shape housing concept design model was reduced by using the topology optimization method. As a result, the rectangular and circular shape housing design reduced 92.9% and 96.0%, respectively. Finally, the vibration was effectively reduced while maintaining the electromagnetic characteristics of the motor, for which topology optimization was conducted while not changing the rotor or stator shape design (electromagnetic design factor) but by changing the motor housing shape design (mechanical and structural design factor)

Direct Writing and Aligning of Small-Molecule Organic Semiconductor Crystals via "Dragging Mode" Electrohydrodynamic Jet Printing for Flexible Organic Field-Effect Transistor Arrays

Patterning and aligning of organic small-molecule semiconductor crystals over large areas is an important issue for their commercialization and practical device applications. This Letter reports "dragging mode" electrohydrodynamic jet printing that can simultaneously achieve direct writing and aligning of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN) crystals. Dragging mode provides favorable conditions for crystal growth with efficient controls over supply voltages and nozzle-to-substrate distances. Optimal printing speed produces millimeter-long TIPS-PEN crystals with unidirectional alignment along the printing direction. These crystals are highly crystalline with a uniform packing structure that favors lateral charge transport. Organic field-effect transistors (OFETs) based on the optimally printed TIPS-PEN crystals exhibit high field-effect mobilities up to 1.65 cm(2)/(V-s). We also demonstrate the feasibility of controlling pattern shapes of the crystals as well as the fabrication of printed flexible OFET arrays.113sciescopu

Index Terms

In today’s IEEE 802.11 Wireless LANs (WLANs), e.g., the popular IEEE 802.11b, stations support multiple transmission rates, and use them adaptively depending on the underlying channel condition via link adaptation. It has been known that when some stations use low transmission rates due to bad channel conditions, the performance of the stations using high rates is heavily degraded, and this phenomenon is often referred to as performance anomaly. In this paper, we model the WLAN incorporating stations with multiple transmission rates in order to demonstrate the performance anomaly analytically. Note that all the previously-proposed models of the IEEE 802.11 assume a single transmission rate. We also develop possible remedies to improve the performance. Our solution is basically to control the access parameters such as the initial backoff window, the frame size, and the maximum backoff stage, depending on the employed transmission rate. Throughout simulations, we demonstrate that our analytical model is accurate, and the proposed mechanism can indeed provide the remedies to the performance anomaly by increasing the aggregate throughput up to six times

GPU-Accelerated Framework for Intracoronary Optical Coherence Tomography Imaging at the Push of a Button

Frequency domain optical coherence tomography (FD-OCT) has become one of the important clinical tools for intracoronary imaging to diagnose and monitor coronary artery disease, which has been one of the leading causes of death. To help more accurate diagnosis and monitoring of the disease, many researchers have recently worked on visualization of various coronary microscopic features including stent struts by constructing three-dimensional (3D) volumetric rendering from series of cross-sectional intracoronary FD-OCT images. In this paper, we present the first, to our knowledge, "push-of-a-button" graphics processing unit (GPU)-accelerated framework for intracoronary OCT imaging. Our framework visualizes 3D microstructures of the vessel wall with stent struts from raw binary OCT data acquired by the system digitizer as one seamless process. The framework reports the state-of-the-art performance; from raw OCT data, it takes 4.7 seconds to provide 3D visualization of a 5-cm-long coronary artery (of size 1600 samples x 1024 A-lines x 260 frames) with stent struts and detection of malapposition automatically at the single push of a button

Pharmacokinetic and Pharmacodynamic Evaluation of Marbofloxacin in Pig against Korean Local Isolates of Actinobacillus pleuropneumoniae

The pharmacokinetics of marbofloxacin in pigs after intravenous (i.v.), intramuscular (i.m.), and peroral (p.o.) administration and pharmacokinetic/pharmacodynamic indices of this drug against Korean local isolates of Actinobacillus pleuropneumoniae were determined in this study. Marbofloxacin (2.50 mg/kg of body weight) was administered, and blood samples were collected with designated time intervals. Plasma-extracted marbofloxacin was injected into the LC-MS/MS system. The in vitro and ex vivo antibacterial activities of marbofloxacin were evaluated against 20 isolates of A. pleuropneumoniae. The mean peak plasma concentrations (Cmax) after i.v., i.m., and p.o administration were 2.60±0.10, 2.59±0.12, and 2.34±0.12 µg/mL at 0.25±0.00, 0.44±0.10, and 1.58±0.40 h, respectively. The area under the plasma concentration-time curves (AUC0–24) and elimination half-lives were 24.80±0.90, 25.80±1.40, and 23.40±5.00 h·μg/mL and 8.60±0.30, 12.80±1.10, and 8.60±0.00 h, for i.v., i.m., and p.o. administration, correspondingly. The AUC0–24/MICs of marbofloxacin after i.v., i.m., and p.o. administration were 253.86±179.91, 264.1±187.16, and 239.53±169.75 h, respectively. The Cmax/MIC values were 26.58±18.84, 26.48±18.77, and 23.94±16.97, and T>MICs were 42.80±1.01, 36.40±1.24, and 38.60±1.18 h, after i.v., i.m., and p.o. administration, respectively. Thus, marbofloxacin dosage of 2.50 mg/kg of body weight by i.v., i.m., and p.o. administration with 24 h dosing interval will provide effective treatment for the infection of pig by A. pleuropneumonia

Unified film patterning and annealing of an organic semiconductor with micro-grooved wet stamps

A unified patterning and annealing approach was successfully demonstrated for 5,11-bis(triethylsilylethynyl)-anthradithiophene (TES-ADT) films spun-cast on polymer-treated SiO2 dielectrics. First, rubbery polydimethylsiloxane (mu-PDMS) stamps with microscale periodic grooves were swollen in 1,2-dichloroethane and then softly placed onto amorphous-like TES-ADT films. In this case, the film sides physically in contact with the wet stamps were quickly absorbed into the PDMS matrix while the non-contact area formed highly ordered phases by the solvent-annealing effect. The resulting patterns of TES-ADT contained discernable crystallites, where the grain sizes drastically decreased and their shapes transformed from spherulites to optically featureless ones with a decreasing line width from 100 to 2.5 mu m. Unlike ordinary systems containing spherulitic domains, the 2.5 mu m line-confined TES-ADT patterns contained layer-stacked crystallites but an optically invisible grain boundary, yielding an unexpectedly high field-effect mobility of 2.60 cm(2) V-1 s(-1) in organic field-effect transistors (OFETs), with narrow deviations less than 8% (averaged from 42 devices). The results suggest that the well pi-overlapped grains and their smooth connections are key factors to achieve high performance multi-array OFET applications.1165sciescopu