A resource allocation algorithm for throughput maximization with fairness increase based on virtual PRB in MIMO-OFDMA systems

This paper deals with a new resource allocation algorithm in downlink MIMO-OFDMA systems. The objective is to maximize the system throughput with respect to fairness criteria since some users may experience bad channel conditions for a long time. Known to be NP-hard, the original optimization problem is divided into two sub-problems where radio resource allocation and power allocation are performed separately. Firstly, a recursive PRB allocation algorithm is performed aiming at maximizing the system throughput. In LTE systems, 41% of sub-carriers are considered unused which introduces spectral efficiency loss. As solution, the eNodeB aggregates the unused sub-carriers by each user to construct a “virtual” PRB to be allocated to seldom served user for fairness and throughput increase. Secondly, power allocation is performed to select a more appropriate MCS.

     

System Performance of Transmit Diversity Methods and a Two Fixed-Beam System in WCDMA

Downlink transmit diversity modes for WCDMA together with a two fixed-beam antenna array system are compared relative to the single antenna sectorized system in a radio network simulator. The transmit diversity methods investigated are: space-time transmit diversity and closed-loop mode I transmit diversity. Frequency selective (COST 259) and flat fading channels are considered and their impact to speech-only and data-only services is evaluated. A third service, which highlights the system performance of the various advanced antennas, is also investigated.The results in this investigation point out that the diversity gain in flat fading channels is substantial. In frequency-selective fading, the benefits of fixed beam systems is encouraging, whereas transmit diversity methods (especially Space-Time Transmit Diversity) is unsatisfactory.     

Delayed delivery. Two cases, and review of the literature

Delayed deliveries are rarely encountered in multiple pregnancies. They are useful in case of premature fetus. We report two case of delayed delivery; the first one of 23 days in a twin pregnancy, and the second one of 4 days in a triplet pregnancy. In both cases, the first delivered fetus died, and the later one or ones survived. Delayed delivery is a good management practice for multiple pregnancies in case of prematurity if no contraindications exist.     

Vertebral hemangioma symptomatic during pregnancy. A case report and review of the literature

A simple four-tube arteries-microvessels-veins system which simulates a more realistic loading for human circulation was built using transmission line network. Hemodynamic data from literature are used in the fluid-circuit analogy, and the flow leakage and viscoelastic properties of the blood vessels have been considered. The effect of veins on the input impedance spectrum was found to be negligibly small above 0.5 Hz. The predicted input impedance spectra agree reasonably well with the published measurements both in shape and magnitude. Parametric analysis shows that the changes of vascular properties in the lower body affect the first minimum, and the changes in the upper body influence the second minimum. The blood flow in and out of kidney and liver dominates the aortic impedance from 0 to 5 Hz. Decreasing capacitance (i.e., increasing arterial stiffness due to aging), reducing the lumen area, or decreasing the length of blood vessels result in an increase in the impedance modulus, and the first minimum shift to a higher frequency which agree well with experiments. In the current model, the pressure, flow waveform, and local impedance can be predicted at any location along the circulatory tree. The characteristic of arterial pulse propagation resembles published measurements.     

Identification of the major HOx radical pathways in an indoor air environment

OH and HO₂ profiles measured in a real environment have been compared to the results of the INCA‐Indoor model to improve our understanding of indoor chemistry. Significant levels of both radicals have been measured and their profiles display similar diurnal behavior, reaching peak concentrations during direct sunlight (up to 1.6×10⁶ and 4.0×10⁷ cm^?3 for OH and HO₂, respectively). Concentrations of O₃, NO_x, volatile organic compounds (VOCs), HONO, and photolysis frequencies were constrained to the observed values. The HO_x profiles are well simulated in terms of variation for both species (Pearson's coefficients: p_OH=0.55, p_HO2=0.76) and concentration for OH (mean normalized bias error: MNBE_OH=?30%), HO₂ concentration being always underestimated (MNBE_HO2=?62%). Production and loss pathways analysis confirmed HONO photolysis role as an OH precursor (here up to 50% of the production rate). HO₂ formation is linked to OH‐initiated VOC oxidation. A sensitivity analysis was conducted by varying HONO, VOCs, and NO concentrations. OH, HO₂, and formaldehyde concentrations increase with HONO concentrations; OH and formaldehyde concentrations are weakly dependent on NO, whereas HO₂ concentrations are strongly reduced with increasing NO. Increasing VOC concentrations decreases OH by consumption and enhances HO₂ and formaldehyde.     

Traffic Signs Detection for Real-World Application of an Advanced Driving Assisting System Using Deep Learning

Neural Processing Letters - Recent advanced driving systems are used as luxury tools to handle a difficult or repetitive task. One of the most important tasks is traffic signs detection that...     

Energy Efficient Siloxane Lubricants Utilizing Temporary Shear-Thinning

This study investigates the rheologic properties, elastohydrodynamic film, and friction coefficients of several siloxane-based lubricants to assess their shear stability and their potential for energy efficient lubrication. Several siloxane-based polymers with alkyl, aryl, and alkyl-aryl branches were synthesized in order to examine the relationship between their molecular structures and tribological performance. Nuclear magnetic resonance spectroscopy and gel permeation chromatography were used to characterize the molecular structures and masses, respectively. Density, viscosity, elastohydrodynamic film thickness, and friction measurements were measured from 303 to 398 K. Film thickness and friction measurements were made at loads and speeds that cover the boundary, mixed, and full film lubrication regimes. These results illustrate that the shear characteristics of siloxane lubricants vary significantly with polymer length as well as branch structure and content. The findings provide quantitative insight into the features of siloxane molecular structure conducive to optimum film formation with minimum wear and elastohydrodynamic friction to enhance energy efficiency.     

An Evaluation of RetinaNet on Indoor Object Detection for Blind and Visually Impaired Persons Assistance Navigation

Neural Processing Letters - Indoor object detection presents a computer vision task that deals with the detection of specific indoor classes. This task attracts a lot of attention, especially in...     

Thin‐wall injection molding of polypropylene using molds with different laser‐induced periodic surface structures

In injection molding, high pressure is required to completely replicate the mold geometry, due to the viscosity of thermoplastic polymers, the reduced thickness of the cavity, and the low mold temperature. The reduction of the drag required to fill a thin‐wall injection molding cavity can be promoted by inducing the strong slip of the polymer melt over the mold surface, which occurs within the first monolayer of macromolecules adsorbed at the wall. In this work, the effects of different laser‐induced periodic surface structures (LIPSS) topographies on the reduction of the melt flow resistance of polypropylene were characterized. Ultrafast laser processing of the mold surface was used to manufacture nano‐scale ripples with different orientation and morphology. Moreover, the effects of those injection molding parameters that mostly affect the interaction between the mold surface and the molten polymer were evaluated. The effect of LIPSS on the slip of the polymer melt was modeled to understand the effect of the different treatments on the pressure required to fill the thin‐wall cavity. The results show that LIPPS can be used to treat injection mold surfaces to promote the onset of wall slip, thus reducing the injection pressure up to 13%. POLYM. ENG. SCI., 59:1889–1896, 2019. © 2019 Society of Plastics Engineers     

Effect of Different Drying Procedures on the Nutritional Value of the Mantle and Tentacles of <Emphasis Type="Italic">Sepia officinalis</Emphasis>

The aim of this work was to investigate the influence of two different drying methods, traditionally by sun and controlled temperatures of 45, 50, 60 and 70 °C and relative humidity of 20 and 30% on the chemical composition of Sepia officinalis. When compared to fresh samples, lipid content increased under both drying methods whereas protein levels significantly increased only under controlled conditions. Drying procedures increased the percentage of saturated fatty acids mainly in sun‐dried samples and at high temperature (70 °C). A significant decrease in the amount of polyunsaturated fatty acids was detected in sun‐dried samples. No significant differences were found between the levels of polyunsaturated fatty acids of fresh cuttlefish and those under controlled conditions. The highest value of malondialdehyde in mantles was observed in sun‐dried samples, while in tentacles the highest level was seen at 70 °C. The highest level of advanced oxidation protein products was noted in traditionally sun‐dried samples. The results obtained showed that 45–50 °C and 20–30% humidity conserved the value of proteins and lipids more than traditional drying. Results of this study may be suitable for developing a reliable industrial index.