Flow Sensing-Based Congestion Detection for D2D Streaming on a 5G gNB

To provide high-quality streaming services in device-to-device (D2D) communications, performance parameters such as encoding rate, decoding rate, and flow rate should be detected and monitored. The proposed algorithm provides a method to detect time streaming for traffic flows in D2D communications, and a sequence to detect rate imbalance. This paper proposes a new FS-CDA (flow sensing-based congestion detecting algorithm) to prevent high congestion rates and assist an optimized D2D streaming service in 5G-based wireless mobile networks. The proposed algorithm detects and controls flow imbalance for streaming segments during D2D communications, and it includes operations such as transmission rate monitoring, rate adjustment functions, and underflow and overflow sensing for these operations. The paper aims to effectively control traffic flow rates caused by adjacent channel bandwidth, high bit rate error, and heterogeneous radio interference, and to enhance the performance of D2D streaming services by performing such operations. The proposed algorithm for D2D streaming services is measured by deriving the individual weight of certain versions of a streaming flow. Based on the given operations, the simulation results indicated that the proposed algorithm has better performance with respect to average congestion control ratio, PSNR, and average throughput than other methods.

COVID-19 with rapid progression to hypoxemia likely due to imbalance between ventilation and blood flow: A case report

We experienced a case of COVID-19 with hypoxia, which was presumed to be due to the development of ventilation and blood flow imbalance by pulmonary intravascular coagulopathy or hypoxic pulmonary vasoconstriction. Early, short-term combination therapy with remdesivir, nafamostat mesilate and low-dose dexamethasone was extremely effective.

Internal Flow Optimization in a Complex Profile Extrusion Die Using Flow Restrictors and Flow Separators

The control of flow balance at the die exit is the key for successful extrusion of polymers. The complex cross-sectional variation in real-world hollow extrusion profiles intrinsically promotes flow imbalance in the die cavity. Special considerations are required for designing extrusion dies for such profiles. The die design for a complex door frame profile was computationally optimized in this study with the aid of a commercially available software package. The velocity distribution at the die exit, post-die extrudate deformation, temperature distribution, and pressure distribution of a traditional die was investigated in detail and found to be inadequate. A modified die incorporated three distinct features, flow restrictors, flow separators and approach angle of the torpedoes, to achieve a balanced and uniform velocity at the die exit. The flow restrictors and flow separators were added in the pre-parallel zone. Flow restrictors were added on top and bottom of the torpedoes to increase the restriction on polymer flow. A unique inclined flow restrictor was introduced to achieve uniform internal melt flow. Flow separators were added at junctions of outer wall and inner vertical walls to separate the polymer flow into different sections and minimize cross flow between these sections. The addition of these features proved to be highly effective for balancing the velocity distribution at the die exit. The combination of 3-D modeling and simulation is an effective cost and time efficient approach for optimizing complex die designs before manufacturing.

A Gasless Reservoir Solution for Electro-Hydraulic Compact Drives With Two Prime Movers

Due to an increased focus on improving the energy efficiency and compactness of hydraulic linear actuators, the electro-hydraulic compact drive (ECD) has received increased attention lately. In this study the ECD consists of variable-speed electric motors and fixed-displacement pumps, which are directly connected to the cylinder, thus controlling the linear motion in a throttleless manner. Furthermore, ECDs are self-contained systems, i.e. based on a fully enclosed oil circuit, in order to avoid external contamination and air to enter the system and to increase system compactness. Conventionally a low-pressure gas-loaded accumulator is used as an oil reservoir to compensate for the flow imbalance occurring whenever utilizing single-rod cylinders in closed systems. The accumulator pressure is to be kept relatively low to stay within the required limits governed by the permitted pump housing’s pressure. Generally, this pressure is not allowed to exceed 1–3 bar. To avoid violating this limitation, the gas volume must be significantly larger than the actual oil volume, which needs to be stored in the accumulator. This requirement decreases the obtainable compactness of the ECD, especially for systems with a large cylinder stroke. Furthermore, the accumulator represents a potential of gas leakage, which ultimately could result in the ECD being non-functional. This paper presents a gasless reservoir solution, improving the system compactness and avoiding the risk of gas leakage. The proposed solution is based on a bootstrap reservoir which is charged by the lowest cylinder chamber pressure. This strategy is feasible for the class of ECDs that is capable of controlling the lowest cylinder chamber pressure alongside the cylinder motion. An ECD consisting of two electric prime movers is considered as a case study. It is shown how the gasless reservoir may be integrated into the system, and an analysis of how this affects the operating range and the dynamic couplings of the system is presented. This leads to the derivation of a control strategy for the Multi-Input-Multi-Output (MIMO) system based on state decoupling, by defining virtual inputs to control virtual outputs. A numerical study suggests that the reservoir volume may be reduced by approximately 50% for the given system dimensions. The proposed control strategy shows good position tracking performance while also being able to control the reservoir pressure within the pre-defined limits of 1 to 3 bar.