Application Layer Multicast Model with Low Delay and High Stability

As an alternative of Internet protocol(IP)multicast,application layer multicast(ALM)is widely used with the advantage of simplicity and flexibility.However,the existing problems of large transmission delay and poor stability limit the application and development.In this article,to solve these problems,an ALM model based on node potential(NP)and topological index(TI)is proposed.The proposed model considers the factors of node capability and node distance in constructing and maintaining multicast tree to reduce transmission delay and increase stability,and thus it improves the application level in real-time multimedia multicast.The computer simulations prove that the proposed model reduces the ALM transmission delay,increases multicast tree stability effectively,and improves the ALM performance,and therefore it is suitable to apply in large-scale real-time multimedia environment.

An analytical model to estimate the time delay to reach spontaneous ignition considering heat loss in oil reservoirs

During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There is a time delay from the injection to ignition.There are mixed results regarding the feasibility of spontaneous ignition in real-field projects and in laboratory experiments.No analytical model is available in the literature to estimate the oxidation time required to reach spontaneous ignition with heat loss.This paper discusses the feasibility of spontaneous ignition from theoretical points and experimental and field project observations.An analytical model considering heat loss is proposed.Analytical models with and without heat loss investigate the factors that affect spontaneous ignition.Based on the discussion and investigations,we find that it is more difficult for spontaneous ignition to occur in laboratory experiments than in oil reservoirs;spontaneous ignition is strongly affected by the initial reservoir temperature,oil activity,and heat loss;spontaneous ignition is only possible when the initial reservoir temperature is high,the oil oxidation rate is high,and the heat loss is low.

Low-Delay Loop Detection Algorithm for LDPC Codes

Abstract:A low-delay loop detection algorithm for bit-flipping based iteration LDPC decoding is proposed.By introducing the concept of loop characteristic,only the iteration steps with loop characteristics are detected and labeled for the subsequent loop detection.As a result,computation delay is greatly reduced.Furthermore,the position vector for the selected iteration steps is also established to implement loop detection for these iteration steps,which reduces the hardware cost of the loop detection as well.The validity of the proposed algorithm is verified by simulations.

Effects of Placental Transfusion by Delayed Cord Clamping or Umbilical Cord Milking versus Immediate Cord Clamping on Neonatal Outcomes in Very Low Birth Weight Neonates

Background: Delayed cord clamping (DCC) and umbilical cord milking (UCM) are two recently advocated interventions to enhance placental transfusion at birth. DCC and MCM might increase blood volume and help neonates to transition from fetal to neonatal circulation. Objective: To evaluate the effects of delayed cord clamping (DCC), umbilical cord milking (UCM), and immediate cord clamping (ICC) on very low birth weight (VLBW) neonates. Methods: At our institution, ICC was routinely done until December, 2012 when it was replaced by DCC. UCM was implemented in March, 2015. Neonatal outcomes were compared among ICC, DCC, and UCM. Results: A total of 94 neonates met inclusion criteria. Comparing with ICC neonates, DCC and UCM neonates had higher hematocrits, fewer blood transfusions, and lower incidence of chronic lung disease at 36 completed weeks of gestation. All groups were similar in APGAR scores, vasopressor use, intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). Conclusion: Compared to ICC, DCC and UCM appear to be more beneficial to VLBW neonates without apparent adverse risks.

A PCA-Based Internet Delay Space Dividing Algorithm

It's a hot issue to improve the accuracy of network coordinate systems(NCS). By analyzing the error source of NCSes, it's emphasized that guaranteeing the low dimensionality of embedding datasets is the principle on the designing of NCSes. Based on this observation, a PCA based Internet delay space dividing algorithm(IDSD-PCA) is proposed. Beginning at choosing an optimized sub dataset randomly, IDSD-PCA partitions the Internet delay dataset into several sub datasets with low dimensionality by iterations. After the partition, the whole delay dataset and sub datasets are embedded into a hierarchical NCS. The experimental results show that with this framework both the metric space based models and the non-metric space based models can predict the end-to-end delays more accurately.

ANALYSIS OF TRANSIENT CHARACTERISTICS OF ECL CIRCUIT AT LOW TEMPERATURE

Detailed analysis on transient characteristics of ECL circuits are performed in this paper, then a relatively exact propagation delay expression applied for all temperatures is presented. The cryogenic characteristics of some dominant parameters contributed to propagation delay are also discussed. The model achieved is suitable for optimum designs of high speed devices and circuits at all temperatures.

Realizing External Quantum Efficiency over 25% with Low Efficiency Roll-Off in Polymer-Based Light-Emitting Diodes Synergistically Utilizing Intramolecular Sensitization and Bipolar Thermally Activated Delayed Fluorescence Monomer

Since polymer-based light-emitting diodes(PLEDs)arewellsuited building blocks for large-area and low-cost flexible display equipment,state-of-the-art thermally activated delayed fluorescence(TADF)PLEDs are in high demand.To respond to this demand,light-emitting TADF units have initially been modified with electron-transporting units to balance the carrier transport of regiorandom TADF polymers,and simultaneously,an intramolecular sensitizing strategy has also been employed by covalently incorporating TADF sensitizers with light-emitting TADF units and hosts in conjugated polymers to accelerate the spin-flip of triplet excitons.Superior photophysical properties have been achieved by a rational regulation of the proportions of each component,achieving a photoluminescence quantumyield of 90%,an extremely high rate of reverse intersystem crossing of 3×106 s−1,and a relatively low nonradiative decay rate of around 105 s−1.As a result,the solutionprocessed PLEDs can attain an external quantum efficiency(EQE)value of 25.4%with emission peaks of around 550 nm,representing record-high performance for PLEDs.The efficiency roll-off can also be significantly suppressed,maintaining an EQE value of 24.2%at 1000 cd/m2 with ideal efficiency roll-off of lower than 5%.Encouragingly,this work provides a valid strategy to tackle the imperative need for PLEDs with high EQE and low efficiency roll-off.

Interrupt CW Approach for IF Video Signal Real Time Simulating and Its Validity

To determine the feasibility and practicability of interrupt continuous wave (CW) approach proposed for real time simulating radar intermediate frequency(IF) video signal, theoretical analysis and computer simulation were used. Phases at two linked points between the end and beginning of adjoined frames are always consistent; the bias Doppler frequency for the time delay of A/D sampling start responds to that for target acceleration. No digital phase compensation is required at continuous points, and the interrupt CW approach has apparently practical values.

High-throughput low-delay MAC protocol for Tera Hertz ultra-high data-rate wireless networks

To address the problems of the present Tera Hertz medium access control（MAC） protocols such as not updating the time slot requests numbers in time, unreasonable superframe structures and not merging time slot requests from the same pair of nodes, high throughput low delay medium access control（HLMAC）, a novel MAC protocol for Tera Hertz ultra-high data-rate wireless networks is proposed. It reduces the data access delay largely with a new superframe structure, from which nodes can get time slot allocation information immediately. The network throughput is also improved with the help of updating time slot requests number and merging time slot requests from the same pair of nodes. The theoretical analysis verifies the effectiveness of HLMAC, and the simulation results show that HLMAC improves the network throughput by 65.7% and decreases the access delay by 30%, as compared to energy and spectrum-aware medium access control（ES-MAC）.

A Novel Rate Control Method for Low Delay Applications

In real time applications, the low delay rate is an important requirement of video coding. We propose a simple low delay rate control method in this paper for such applications. In this method, target bits are divided into two parts: uncontrolled and controlled bits in the frame layer. The first part is assigned to the header, syntax and motion vectors according to that spent in the previous encoded frame. The second part is assigned to DCT coeffcients by employing a rate model for mactorblock Q P determination. Experiments show that the proposed method can achieve better performance compared with that of the test model TMN5 of H .263, and slightly worse performance, but with lower computation complexity, compared with that of the TMN8 of H.263+ .

基于不同显示终端和编码方式的QoE研究

近年来,随着网络技术和多媒体技术的迅速发展,越来越多的研究致力于提高多媒体观众的感知视频质量的水平,其中,一个重要的研究方向是提高用户的体验质量(Qo E)。Qo E的影响因素主要分为三个层面:服务层面、环境层面及用户层面。本文综合考虑了这三个因素,定量研究了不同的显示终端和不同编码方法对Qo E的影响。本文通过主观实验获得主观评价的数据,分析统计数据并构建了解析模型。利用该模型,可获取在不同显示设备终端下不同的编码方式的视频与用户的主观体验之间的关系,从而能够更好地衡量视频传输中的用户体验,借以对视频传输技术和策略提出指导。

A New Speech Codec Based on ANN with Low Delay

The author designs a new speech codec in this paper, which is based on ANN tocarry out nonlinear prediction . This new codec synthesizes speeches with better quality than theconventional waveform or hybrid codecs does at the same bit rate. Moreover, the most importantcharacteristic of this codec is the low coding delay, which will benefit the enhancement of thespeech communication QoS when we transmit speech signals in IP or ATM networks.

Effect of low operating temperature on the aerodynamic characteristics of a high-speed train

In this study,an improved delayed detached eddy simulation(IDDES)method based on the shear-stress transport(SST)k-ωturbulence model has been used to investigate the underbody flow characteristics of a high-speed train operating at lower temperatures with Reynolds number Re=1.85×10^(6).The accuracy of the numerical method has been validated by wind tunnel tests.The aerodynamic drag of the train,pressure distribution on the surface of the train,the flow around the vehicle,and the wake flow are compared for four temperature values:+15℃,0℃,−15℃,and−30℃.It was found that lower operating t emperatures significantly increased the aerodynamic drag force of the train.The drag overall at low temperatures increased by 5.3%(0℃),11.0%(−15℃),and 17.4%(−30℃),respectively,relative to the drag at+15℃.In addition,the low temperature e nhances the positive and negative pressures around and on the surface of the car body,raising the peak positive and negative pressure values in areas susceptible to impingement flow and to rapid changes in flow velocity.The range of train-induced winds around the car body is significantly reduced,the distribution area of vorticity moves backwards,and the airflow velocity in the bogie cavity is significantly increased.At the same time,the temperature causes a significant velocity reduction in the wake flow.It can be seen that the temperature reduction can seriously disturb the normal operation of the train while increasing the aerodynamic drag and energy consumption,and significantly interfering with the airflow characteristics around the car body.

Statistically uniform intra-block refresh algorithm for very low delay video communication

This paper focuses on the mechanism underlying the overall delay of a real-time video communication system from the time of capture at the encoder to the time of display at the decoder. A detailed analysis is presented to illustrate the delay problem. We then describe a statistically uniform intra-block refresh scheme for very low delay video communication. By scattering intra-blocks uniformly into continuous frames, the overall delay is significantly decreased, and object changes in the scene could be presented to the end user instantly. For comparison, the overall delay and the peak signal-to-noise ratio (PSNR) performance are tested. The experiment results show that an average of approximately 0.1 dB PSNR gain on average is obtained relative to random intra-macroblock refresh algorithm in H.264 JM, and the end-to-end delay performance is significantly improved.

A low-power DCO using inverter interlaced cascaded delay cell

This paper presents a low-power small-area digitally controlled oscillator （DCO） using an inverters interlaced cascaded delay cell （IICDC）. It uses a coarse-fine architecture with binary-weighted delay stages for the delay range and resolution. The coarse-tuning stage of the DCO uses IICDC, which is power and area efficient with low phase noise, as compared with conventional delay cells. The ADPLL with a DCO is fabricated in the UMC 180-nm CMOS process with an active area of 0.071 mm2. The output frequency range is 140-600 MHz at the power supply of 1.8 V. The power consumption is 2.34 mW@ a 200 MHz output.

BCTCP:A Feedback-Based Congestion Control Method

Delay and throughput are the two network indicators that users most care about.Traditional congestion control methods try to occupy buffer aggressively until packet loss being detected,causing high delay and variation.Using AQM and ECN can highly reduce packet drop rate and delay,however they may also lead to low utilization.Managing queue size of routers properly means a lot to congestion control method.Keeping traffic size varying around bottleneck bandwidth creates some degree of persistent queue in the router,which brings in additional delay into network unwillingly,but a corporation between sender and router can keep it under control.Proper persistent queue not only keeps routers being fully utilized all the time,but also lower the variation of throughput and delay,achieving the balance between delay and utilization.In this paper,we present BCTCP(Buffer Controllable TCP),a congestion control protocol based on explicit feedback from routers.It requires sender,receiver and routers cooperating with each other,in which senders adjust their sending rate according to the multiple bit load factor information from routers.It keeps queue length of bottleneck under control,leading to very good delay and utilization result,making it more applicable to complex network environments.

Voltage Controlled Ring Oscillator Design with Novel 3 Transistors XNOR/XOR Gates

In present work, improved designs for voltage controlled ring oscillators (VCO) using three transistors XNOR/XOR gates have been presented. Supply voltage has been varied from [1.8 - 1.2] V in proposed designs. In first method, the VCO design using three XNOR delay cells shows frequency variation of [1.900 - 0.964] GHz with [279.429 - 16.515] μW power consumption variation. VCO designed with five XNOR delay cells shows frequency variation of [1.152 - 0.575] GHz with varying power consumption of [465.715 - 27.526] μW. In the second method VCO having three XOR stages shows frequency variation [1.9176 - 1.029] GHz with power consumption variation from [296.393 - 19.051] μW. A five stage XOR based VCO design shows frequency variation [1.049 - 0.565] GHz with power consumption variation from [493.989 - 31.753] μW. Simulations have been performed by using SPICE based on TSMC 0.18μm CMOS technology. Power consumption and output frequency range of proposed VCOs have been compared with earlier reported circuits and proposed circuit’s shows improved performance.

A Handover Strategy in the LEO Satellite-Based Constellation Networks with ISLs

A new handover strategy named minimal-hops handover(MHH) strategy for the lowearth orbit(LEO) satellite constellations networks equipped with inter-satellite links(ISLs) is proposed.MHH strategy,which is based on the hops of the end-to-end connection paths and makes good use of theregularity of the constellation network topology,can appropriately combine the handover procedure withrouting and efficiently solve the inter-satellite handover issue.Moreover,MHH strategy can providequality of services(QoS) guarantees to some extent.The system performances of the MHH strategy,suchas time propagation delay and handover frequency,are evaluated and compared with that of otherprevious strategies.The simulation results show that MHH strategy performs better than other previoushandover strategies.

Novel thioxanthone host material with thermally activated delayed fluorescence for reduced efficiency roll-off of phosphorescent OLEDs

2,7-Di（9,9-dimethyl-9H-fluoren-l-yl）-9H-thioxanthen-9-one （DMBFTX） with thermally activated delayed fluorescence （TADF） was well designed and synthesized. The phosphorescent organic lightemitting device （PHOLED） based on this novel TADF host material displays a stable red phosphorescence region, a peak external quantum efficiency （EQE） value of 12.9% and a low EQE roll-off of 38.8%at a luminance of 10000 cd/m2, which is benefited from the reverse intersystem crossing （RISC） of TADF host and less populated triplet exitons. Notably, the red device based on the TADF host DMBFrX exhibits superior electroluminescence performance and reduced efficiency roll-offcompared with the one hosted by commercially available host 1,3-bis（9-carbazolyl）benzene （mCP）, illustrating the high potential of employing the TADF host material with small energy gap to reduce efficiency roll-off in PHOLED.

A low power time-interleaved 10-bit 250-MSPS charge domain pipelined ADC for IF sampling

A 10-bit 250-MSPS two-channel time-interleaved charge-domain（CD） pipelined analog-to-digital converter （ADC） is presented.MOS bucket-brigade device（BBD） based CD pipelined architecture is used to achieve low power consumption.An all digital low power DLL is used to alleviate the timing mismatches and to reduce the aperture jitter.A new bootstrapped MOS switch is designed in the sample and hold circuit to enhance the IF sampling capability.The ADC achieves a spurious free dynamic range（SFDR） of 67.1 dB,signal-to-noise ratio （SNDR） of 55.1 dB for a 10.1 MHz input,and SFDR of 61.6 dB,SNDR of 52.6 dB for a 355 MHz input at full sampling rate.Differential nonlinearity（DNL） is ＋0.5/-0.4 LSB and integral nonlineariry（INL） is ＋0.8/-0.75 LSB.Fabricated in a 0.18-μm 1P6M CMOS process,the prototype 10-bit pipelined ADC occupies 1.8×1.3 mm2 of active die area,and consumes only 68 mW at 1.8 V supply.