Probability Of Successful Delivery Research Articles

Understanding the impact of persistence and propagation on the Age of Information of broadcast traffic in 5G NR-V2X sidelink communications

The current Cellular V2X (C-V2X) standard for direct communication between vehicles is based on the so called Semi-Persistent Scheduling (SPS) algorithm. It is based on the multiple access structure of 5G New Radio (NR) and exploits sensing and persistence to realize a randomized multiple access. We consider the application of SPS to support periodic broadcast traffic where no acknowledgments are provided. Persistence is a key feature, which consists of a node using the same resource for its transmissions for multiple frames. The specific resource used is randomly selected from among those that are perceived to be idle, and reselected anew after a randomized number of frames. We define a model to gain insight into the interplay between persistence and key performance metrics for the type of traffic considered, namely probability of successful delivery and Age of Information (AoI). A core version of the model is validated against simulations and used to show that there exists an optimal level that minimizes AoI. The model is then extended to account for a distance-dependent propagation model, allowing further insight into the effects of the interplay between sender–receiver distance and persistence. Finally, an even more detailed model is investigated, using ns-3-based simulations. This further analysis confirms the qualitative behaviors revealed by the analytical model and provides more insight into the complex interactions of system parameters and channel characteristics. The obtained results help to identify the limits of SPS, opening the way to system-principled parameter optimization and design of more powerful variants of the multiple access scheme.

METHODOLOGY OF THE RATIONALE OF AN AMOUNT OF UNMANNED CARGO DELIVERY SYSTEMS

It is possible to reduce human losses during the cargo delivery to units on the battlefield with the use of unmanned systems (UMSs), including logistical unmanned ground vehicles (UGV) of various groups carrying capacity and unmanned aircraft systems (UAS). The urgent task is to determine the required number of unmanned cargo delivery systems in the interests of the mechanized infantry battalion. The method of determining the number of unmanned cargo delivery systems for the logistical means (LM) transportation to the units of the mechanized infantry battalion is described. The optimality criterion of the selected composition of the system is the maximum efficiency-cost ratio (ECR) under the condition of transporting the maximum weight of LM required for the battle day from the combat supply point to the units of the mechanized infantry battalion. In this case, the efficiency indicator is the share of the total weight of LM that must be delivered to the units. In order to calculate this indicator, it is necessary to estimate the probability of successful delivery of LM to different battalion units for each UMSs. The cost indicator is the product of the masses of the cargo and energy costs on the delivery route, purchase costs and total costs for operating the UMSs during the forecasted average life of operation in terms of 1 kg of cargo. Two transport tables are built based on the results of the calculations. The first table includes probability weighting factors, and the second includes weighting factors of the cost of delivering LM from a combat supply point to units by various UMSs. For each of these transport problems, the optimal solution is obtained by linear programming methods, and for the ECR, by methods of optimization of problems with a nonlinear objective function, which is illustrated by an example using the "Solver" add-on in the Excel spreadsheet processor. Keywords: logistic support, unmanned systems, logistical unmanned ground vehicles, unmanned aircraft systems, load capacity, cargo delivery, efficiency-cost, optimization of an amount.

Spatial modeling and reliability analyzing of reconfigurable intelligent surfaces-assisted Fog-RAN with repulsion

Reconfigurable Intelligent Surface (RIS), fog computing, and Cell-Free (CF) network architecture are three promising technologies for application to the Ultra-Reliable Low Latency Communication (URLLC) scenario in 6G mobile communication systems. This paper considers a RIS-assisted FogRadio Access Network (Fog-RAN) architecture where a) the repulsively distributed Fog-Access Points (F-APs) communicate in a CF manner to suppress inter-cell interference, b) RISs are introduced into the CF network to avoid shadowing and enhance the system performance, and c) fog computing evolved as cloud services providers at the edge of the network and an enabler for constructing a multi-layer computing power RAN. Then, we derive and validate the integral form of the maximum F-AP offloading probability and Successful Delivery Probability (SDP) of this RIS-assisted Fog-RAN over composite Fisher-Snedecor F fading, where the spatial effects are reconsidered with the assumption that the F-APs are modelled as a Beta Ginibre Point Process (β-GPP). The numeric and simulation results indicate that for the investigated RIS-assisted Fog-RAN, the β-GPP-based deployment of F-APs can increase maximum of 8% of the SDP within the repulsion-effective range, compared with the Matern Cluster Process (MCP)-based ones. Also, deploying more RISs per F-AP offers more significant SDP improvements.

Optimizing Average Age of Information in Industrial IoT Systems Under Delay Constraint

Age of Information (AoI) is a new metric that can measure the data freshness of the Industrial Internet of Things (IIoT) systems. Focusing on a hybrid scenario where periodic and random sampling devices exist simultaneously, we investigate AoI-aware scheduling schemes under deterministic delay constraint of devices with periodic sampling in noisy channels. We first consider that the probability of successful delivery of data obeys a known fixed probability, and develop a dynamic scheduling scheme utilizing the slot-based Lyapunov drift framework. Secondly, for the case where the prior knowledge of the probability of successful data delivery is unknown, we introduce Deep Reinforcement Learning (DRL) to learn the model-free scheduling and propose a scheduling policy based on the Dueling Deep Q Network (D3QN). Numerical results show that the proposed Lyapunov policy and D3QN policy can minimize the average AoI while subjecting to the delay constraint.

On the Performance Analysis of Epidemic Routing in Non-Sparse Delay Tolerant Networks

We study the behavior of epidemic routing in a delay tolerant network as a function of node density. Focusing on the probability of successful delivery to a destination within a deadline (PS), we show that PS experiences a phase transition as node density increases. Specifically, we prove that PS exhibits a phase transition when nodes are placed according to a Poisson process and allowed to move according to independent and identical processes with limited speed. We then propose four fluid approximations to evaluate the performance of epidemic routing in non-sparse networks. An ordinary differential equation (ODE) is proposed for supercritical networks based on approximation of the infection rate as a function of time. Other ODEs are based on the approximation of the pairwise infection rate. Two of them, one for subcritical networks and another for supercritical networks, use the pairwise infection rate as a function of the number of infected nodes. The other ODE uses pairwise infection rate as a function of time, and can be applied for both subcritical and supercritical networks achieving good accuracy. The ODE for subcritical networks is accurate when density is not close to the percolation critical density. Moreover, the ODEs that target only supercritical regime are accurate.

UAV Fleet as a Dependable Service for Smart Cities: Model-Based Assessment and Application

The paper suggests a model-based approach to assessment and choice of parameters of unmanned aerial vehicle (UAV) fleets applied as one of the main services for Smart Cities and recommendations to assure their dependability. The principles of building and modeling a UAV Fleet as a Dependable Service (UAVFaaDS) for Smart Cities are formulated. Dependability issues for UAVFaaDS including a taxonomy of UAVF failures caused by equipment faults and attacks on assets were specified. The main results cover methodology, classification of UAVFaaDS models as models of queuing systems, and a set of queueing theory-based models for assessment of UAVFaaDS performance, and availability allowing for analysis and choice of fleet parameters. The efficiency of UAVFaaDS is assessed by the probability of successful delivery of services. The proposed modeling base and algorithms provide a choice of appropriate models for analysis and synthesis of UAVFaaDS, grounding of parameters of UAV fleets considering operation modes, and maintenance policy. The application of the developed models and algorithms during the synthesis of UAVFaaDS allows choosing the appropriate parameters of the fleet and ensuring the dependability of services, as well as service of orders with a probability of 0.9–0.99 depending on the requirements. Two cases of UAVFaaDS application for delivery of medicines in normal and emergence modes, models’ development, and recommendations for their utilization are discussed.

Performance modeling of Licklider transmission protocol (LTP) via proactive transmission of signaling segments in deep‐space network

SummaryDelay‐tolerant networking (DTN) bundle protocol is considered one of the best transmission protocols to be used in space communications by NASA. There are studies that evaluated the performance, measuring the total transfer time of a complete file from sender to receiver, of the DTN protocol via simulation or emulated experiments beyond the real space‐based experiences. In addition, there is a very few additional research works available for the modeling of the Licklider transmission protocol (LTP). However, these past studies on LTP modeling are implemented as a Logarithmic approach that is based on the calculation of loss segments in file delivery. In this work, the approach is investigated in a different manner. Specifically, the performance model was created based on the probability of the segment's successful delivery on the LTP. Moreover, the original model is enhanced via introducing a burst of transfer and equal interval distribution of signaling segments, specifically check point (CP), along with the retransmission time out (RTO). The results from the developed model for the original DTN protocol and enhanced versions align with the results obtained by PC‐based testbeds.

Improving Delivery Probability in Mobile Opportunistic Networks with Social-Based Routing

There are contexts where TCP/IP is not suitable for performing data transmission due to long delays, timeouts, network partitioning, and interruptions. In these scenarios, mobile opportunistic networks (MONs) are a valid option, providing asynchronous transmissions in dynamic topologies. These architectures exploit physical encounters and persistent storage to communicate nodes that lack a continuous end-to-end path. In recent years, many routing algorithms have been based on social interactions. Smartphones and wearables are in vogue, applying social information to optimize paths between nodes. This work proposes Refine Social Broadcast (RSB), a social routing algorithm. RSB uses social behavior and node interests to refine the message broadcast in the network, improving the delivery probability while reducing redundant data duplication. The proposal combines the identification of the most influential nodes to carry the information toward the destination with interest-based routing. To evaluate the performance, RSB is applied to a simulated case of use based on a realistic loneliness detection methodology in elderly adults. The obtained delivery probability, latency, overhead, and hops are compared with the most popular social-based routers, namely, EpSoc, SimBet, and BubbleRap. RSB manifests a successful delivery probability, exceeding the second-best result (SimBet) by 17% and reducing the highest overhead (EpSoc) by 97%.

Cross-Layer Design Based N-ary Huffman Coding for Performance Analysis of DSDV Routing Protocol in MANETs

The implementation of the optimal Huffman coding technique for achieving proficient data compression, lower information redundancy and minimal utilization of the scarce bandwidth is essential to handle the effective processing of massive network data. In this paper, we employ cross-layer design technique among the data link, network and presentation layers of the traditional protocol stack to develop the improved DSDV routing protocol based on n-ary Huffman coding procedure. The entropy-based adaptive prefix codewords with variable length are assigned to the probability of packet successful delivery across the ad-hoc wireless network. Several coding and network efficiency parameters are deployed to assess the performance of the proposed routing scheme under three distinctive IPv4 network scenarios. These investigated network protocols include the default IPv4, multi IPv4 and dynamic IPv4 routing methodologies. Diversified simulation settings are employed with deviating network size to measure the multitude of essential wireless network characteristics incorporating the average delay, packet error rate, packet delivery fraction, data rate, ping loss rate, entropy rate, and reception cache hit. In addition, the set of key data compression/coding indicators are examined through comprehensive numerical analysis such as codeword length, source information rate, mean redundancy, and coding efficiency. Beyond, we significantly compare the performance of our developed cross-layer coded mobile routing model with several previous algorithms to validate its enhanced feasibility and superiority in terms of crucial network operation metrics such as throughput, packet drop rate, mean delay and packet delivery ratio.

Two-Tier Cache-Aided Full-Duplex Hybrid Satellite–Terrestrial Communication Networks

Enabling global Internet access is challenging for cellular-based Internet of Things (IoT) due to the limited range of terrestrial network services. One viable solution is to deploy IoT over satellite systems for coverage extension. However, operating a hybrid satellite–terrestrial network might incur high satellite bandwidth consumption and excessive service latency. Aiming to reduce the content delivery latency from the Internet-connected gateway to the users, this article proposes a two-tier cache-enabled model with full-duplex transmissions where content caches are deployed at the satellite and ground station. A closed-form solution for the successful delivery probability (SDP) of the files is derived considering the requested content distributions and channel statistics. Then, the SDP performance under common caching policies can be evaluated. The results are also used to optimize cache placement under caching capacity constraints. Numerical results demonstrate the performance improvements of the proposed system over those of single-tier cache-aided and half-duplex transmission systems.

Performance Evaluation of LTE Random Access Procedure under Distributed Location Data Mining for Road Traffic Monitoring

The widely-used cellular system, such as LTE, has a large potential to serve vehicle-related connectivity which is one of the potential IoT market in the near future. However, the connection-oriented nature of LTE Random Access procedure remains the challenge. The RA procedure in LTE is prone to be overloaded with simultaneous access request from large number of mobile users. This overload condition is likely to happen due to synchronized location reporting for road traffic monitoring in Intelligent Transportation System (ITS). This work studies the performance of RA procedure under overload condition in term of probability of successful report delivery and average report delivery delay. Subsequently, two proposals are made to increase the performance: report time spreading and truncated binary exponential decrease backoff mechanism. The two proposals are evaluated and compared with the existing configuration of LTE RA procedure. Our simulation results show that both proposals can increase the probability of successful report delivery and obtain fairly low average report delivery delay, which is necessary for accurate location reporting and road traffic monitoring system.

Optimal Throughput for Multicast over MANET-Satellite Networks

The convergence of MANET and satellite networks has been considered as one of the potential solutions to provide emergency communication and disaster relief services. However, unreliable MANET and satellite links may influence seriously to data transmission. In this paper, we study the application of packet-level coding for enhancing network throughput for multicast services over integrated MANET-satellite networks. First, we characterize the performance of multicast networks in terms of the probability of packet delivery under different packet-level codes. We then formulate and solve the coding optimization problem for typical values of computational resources at the network nodes given some target probability of successful delivery to the receivers. Finally, several simulation results show significant gains in the average achievable rate at the receivers with respect to routing for representative scenarios with different types of network devices given a strictly-high probability of successful delivery of the multicast networks. Furthermore, the devices with higher computational resources can obtain significantly better throughput gain.

Caching modeling and energy analyzing of cell-free wireless heterogeneous networks with beta Ginibre point process

Cell-free Wireless Heterogeneous Networks (HetNets) have emerged as a technological alternative for conventional cellular networks. In this paper, we study the spatially correlative caching strategy, the energy analysis, and the impact of parameter β on the total energy cost of the cell-free wireless HetNets with Access Points distributed by Beta Ginibre Point Process (β-GPP). We derive the approximate expression of Successful Delivery Probability (SDP) based on the Signal-to-Interference-plus-Noise Ratio coverage model. From both analytical and simulation results, it is shown that the proposed caching model based on β–GPP placement, which jointly takes into account path loss, fading, and interference, can closely simulate the caching performance of the cell-free HetNets in terms of SDP. By guaranteeing the outage probability constraints, the analytical expression of the uplink energy cost is also derived. Another conclusion is that with AP locations modeled by β-GPP, the power consumption is not sensitive to β, but is sensitive to the dimension of the kernel function; hence β is less restrictive, and only the truncation of the Ginibre kernel has to be appropriately modified. These findings are new compared with the existing literature where the nodes are commonly assumed to be of Poisson Point Process, Matérn Hard-Core Process, or Poisson Cluster Process deployment in cell-free systems.

Prediction of labor outcome by measuring the angle of progression using two dimensional trans-perineal Ultrasound: A prospective cohort study

Background: Failure of descent due to fetal malposition is one of the most common indications for performing surgical deliveries. It has recently been suggested that trans-perineal intra-partum ultrasonography may be useful in assessing fetal head engagement, position and station as well as it’s reliable, cheap, painless and effective tool. Measuring the ‘angle of progression’ could assist in the obstetrician’s decision regarding mode of delivery. Objectives: The primary outcome is to use the AOP to develop a predictive model for the probability of successful vaginal delivery. Secondary outcomes including assessment of possibly successful VBAC in previous one CS women. Methods: We recruited 500 women in labor. For each woman, a (TPU) was performed to measure the AOP in late first and second stages of labor. We compared AOP between women who delivered fetuses through vaginal route to those who delivered by CS. Results: Through 467 women included in the study, AOP was significantly Higher in spontaneous vaginal delivery group (with cut off 123°±8.5°) as compared with women delivered by vacuum or by CS (113°±10.5°) (P=0.003). The VBAC as another secodary outcome seems to be insignificant. Conclusions: TPU is safe, non-invasive and easily preformed technique which is useful to predict labor outcomes.

THE AUTONOMOUS UNMANNED AERIAL VEHICLE GROUP APPLICATION CONCEPT OF THE CLUSTER OF OBJECTS OF INTEREST PAYLOAD DELIVERY

The modern weapons key features are: autonomy, precision, long arm (range more than 2000 km). Such AUAV (Autonomous Unmanned Aerial Vehicles) are quite expensive. The traditional way of delivering a payload is a priori programming each AUAV to the concrete OI (Object of Interest). Since the probability of successful payload delivery is usually about 0.8 or less, then to increase the successful solution probability to the problem posed, the method of launching two or more AUAVs at one OI is used. Thus, a method that minimizes the cost of a solution, i.e. minimizes the AUAV squad, while maintaining a given probability of completing a flight task is of obvious economic interest. A flock of AUAVs can exchange data before the payload delivery, before the final guidance stage, distribute the available AUAVs to the OI to maximize the total task efficiency. To solve the problem of AUAV reprogramming, a method of AUAV data exchange in the synchronization zone is proposed. The geometrical parameters of the zone, the possibility of radio communication with the required exchange rate, and the speed of the synchronization algorithms have been determined. The program exchange parameters are determined and one of the possible Raft algorithms is selected for solving consensus problems in the unreliable computations network.

A comparison of antenatal prediction models for vaginal birth after caesarean section

An antenatal scoring system for vaginal birth after caesarean section (VBAC) categorises patients into a low or high probability of successful vaginal delivery. It enables counselling and preparation before labour starts. The current study aims to evaluate the role of Grobman nomogram and the Kalok scoring system in predicting VBAC success in Singapore. This is a retrospective study on patients of gestational age 37 weeks 0 day to 41 weeks 0 day who underwent a trial of labour after 1 caesarean section between September 2016 and September 2017 was conducted. Two scoring systems were used to predict VBAC success, a nomogram by Grobman et al. in 2007 and an additive model by Kalok et al. in 2017. A total of 190 patients underwent a trial of labour after caesarean section, of which 103 (54.2%) were successful. The Kalok scoring system (area under curve [AUC] 0.740) was a better predictive model than Grobman nomogram (AUC 0.664). Patient's age (odds ratio [OR] 0.915, 95% CI [confidence interval] 0.844-0.992), body mass index at booking (OR 0.902, 95% CI 0.845-0.962), and history of successful VBAC (OR 4.755, 95% CI 1.248-18.120) were important factors in predicting VBAC. Neither scoring system was perfect in predicting VBAC among local women. Further customisation of the scoring system to replace ethnicity with the 4 races of Singapore can be made to improve its sensitivity. The factors identified in this study serve as a foundation for developing a population-specific antenatal scoring system for Singapore women who wish to have a trial of VBAC.

573 Effect of increasing body mass index on infectious morbidity at the extremes of obesity

While the risks associated with obesity in pregnancy are well-appreciated, very little data on the effects of extreme obesity on postpartum outcomes exists. The objective of this study was to evaluate the impact of extreme obesity on infectious morbidity and wound complications during the postpartum period. Retrospective cohort analysis included women with a body mass index (BMI) ≥40kg/m2 delivering at a single tertiary care hospital from 2013-2017. The primary outcome was postpartum infectious morbidity including endometritis, wound infection, and wound seroma. Bivariate statistics was used to compare baseline demographics, pregnancy complications, and primary outcomes among women by increasing BMI groups (40-49.9kg/m2, 50-59.9kg/m2, 60-69.9kg/m2, and >70kg/m2). Regression modeling was used to estimate odds of primary infectious composite and components. Of 374 women included, 244(65.2%) had a BMI 40-49.9kg/m2, 113(35.5%) BMI 50-59.9kg/m2, 13(3.4%) BMI 60-69.9kg/m2, and 4(1.0%) BMI>70kg/m2. Rates of chronic hypertension and weight gain increased with BMI category (Table 1). Increased estimated blood loss and lower rates of vaginal delivery were also seen with increasing BMI category (Table 1). The composite was not significantly different among increasing BMI groups, though rates of postpartum wound infection (2.9% vs 5.3% vs 23.1 % vs 0%, p<0.01) did vary (Table 2). After adjusting for confounders, compared to women with BMI40-49.9, adjusted odds of infectious composite and postpartum wound infection for women with BMI 60-69.9 were 1.91 (95% 0.31-11.8) and 11.01 (95% 1.90-64.0) respectively. Women with BMI 50-70 are at an increased risk of infectious morbidity compared to women with BMI 40-49.9. The lower probability of successful vaginal delivery among women with extremes of BMI raises the question regarding the utility of attempted vaginal delivery in this population. Providers should consider the increased infectious risk when counseling women with BMI>50.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Content Caching and Channel Allocation in D2D-Assisted Wireless HetNets

The fifth generation cellular networks are required to provide very fast and reliable communications while dealing with the increase of users traffic. In heterogeneous networks (HetNets) assisted with device-to-device (D2D) communications, traffic can be offloaded to small base stations or to users to make content delivery faster and alleviate the traffic burden from the core network. In this paper, we aim to maximize the probability of successfully delivering files to users, referred to as the successful delivery probability, by jointly optimizing the caching placement and channel allocation in cache-enabled D2D-assisted HetNets. First, an analytical expression of the average content delivery delay is derived. The latter is subsequently used to formulate the joint optimization problem of cache placement and channel allocation. Due to the problem’s non-convexity, a linearization transformation is proposed, which allows to find the optimal solution. However, given the high complexity of the problem, we propose a low-complex heuristic approach for channel allocation and caching. Numerical results illustrate the efficacy of the proposed solutions and compare them to the conventional HetNet. Finally, the impact of several key parameters, e.g., transmit power, caching capacity, and QoS requirements, is investigated, which provides design guidelines for D2D-assisted HetNets.

A Link-Layer Synchronization and Medium Access Control Protocol for Terahertz-Band Communication Networks

In this paper, a link-layer synchronization and medium access control (MAC) protocol for very-high-speed wireless communication networks in the Terahertz (THz) band is presented. The protocol relies on a receiver-initiated handshake to guarantee synchronization between transmitter and receiver. Two scenarios are considered, namely, a macroscale scenario, where nodes utilize rotating directional antennas to periodically sweep the space while overcoming the distance problem at THz frequencies, and a nanoscale scenario, where nano-devices require energy harvesting systems to operate. Both scenarios are implemented on a centralized and an ad-hoc network architecture. A carrier-based physical layer is considered for the macro-scenario, whereas the physical layer for the nano-scenario is based on a femtosecond-long pulse-based modulation scheme with packet interleaving. The performance of the proposed MAC protocol is analytically investigated in terms of delay, throughput and probability of successful packet delivery, and compared to that of an adapted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) with and without handshake. The results are validated by means of extensive simulations with ns-3, in which all the necessary THz elements have been implemented. The results show that the proposed protocol can maximize the successful packet delivery probability without compromising the achievable throughput in THz-band communication networks.

Impact of Jamming Attacks on Vehicular Cooperative Adaptive Cruise Control Systems

Cooperative Adaptive Cruise Control (CACC) is considered as a key enabling technology to automatically regulate the inter-vehicle distances in a vehicle string, and improve the traffic throughput efficiency. In the existing CACC systems, the coupling between wireless communication uncertainty, and system states is not well modeled. In this paper, we integrate the jamming attacks, and wireless channel fading effects into the CACC state space equations such that it effectively captures the coupling impact. Then, we propose a novel time domain approach to analyze the mean string stability (MSS) of such a model. Based on the proposed model, we analyze the impact of the jammer's location on the string stability. We derive a sufficient condition for the packet successful delivery probability which indicates that the jammer has a higher probability to destabilize the string when it is closer to the first vehicle following the lead vehicle. We also propose a methodology to compute the upper, and lower bounds of the inter-vehicle distance trajectories between the lead vehicle, and its follower. Furthermore, string safety is investigated by numerically estimating the collision probability across the string. We conduct comprehensive Monte Carlo simulations to evaluate the stability, and safety of the string in various scenarios. We identify that string stability, and safety are highly influenced by the jamming attacks signal, and jammer's location. We show the consistency between the main results achieved by MSS analysis, and the Monte Carlo simulations.