Transmission Failure Rate Research Articles

Time-Efficient Joint UAV-BS Deployment and User Association Based on Machine Learning

In this paper, a time-efficient mechanism is proposed to solve the joint unmanned aerial vehicle (UAV) base station deployment and user/sensor association (UDUA) problem aiming at maximizing the downlink sum transmission throughput and reducing the time of on-line computations. In this work, two relevant sub-problems are decoupled from the joint UDUA problem: the first one is denoted as the user association sub-problem, for certain UAV base station (UAV-BS) positions, this sub-problem is settled for finding the strategy which matches aerial and ground nodes optimally. The second sub-problem is the positioning of UAV-BSs in order to obtain the best possible solution to the user association sub-problem from all possible positioning combinations for the UAV-BSs. In the proposed mechanism, the Kuhn-Munkres algorithm is used to solve the first sub-problem as an equivalent bipartite matching problem. For the UAV-BS deployment sub-problem, when the two user distributions own a high similarity, we theoretically prove that little performance decline will be introduced when the new user distribution’s optimal strategy is compared with choosing the optimal UAV-BS deployment strategy of stored user distributions. Based on our mathematical analyses, the similarity level between user distributions is well defined and becomes the key to solve the second sub-problem. According to experimental findings, the proposed UDUA mechanism, when compared to benchmark approaches, can provide near-optimum system performance with regard to average downlink total transmission throughput and failure rate with significantly decreased computing time.

Constructing Multiple CISTs on BCube-Based Data Center Networks in the Occurrence of Switch Failures

The scale of data center networks (DCNs) has grown rapidly with the increasing popularity of cloud computing, data explosion, and the dramatic drop in setup costs. Thus, inevitable component failures (including switches and servers) will become more frequent. A DCN requires maintaining regular and reliable operation and providing efficient routing algorithms for transmitting data between servers. Particularly, fault-tolerant routing is necessary. Recently, constructing completely independent spanning trees (CISTs) on DCNs has received much attention as a dual-CIST (i.e., two CISTs) suffices to configure protection routing, which is a fault-tolerant routing. Moreover, the protection routing can additionally realize a secure mechanism if it is configured by more CISTs. BCube is a server-centric DCN with many advantages, and many variations were deformed from BCube with application requirements, such as RCube and RRect. In this paper, we provide a unified framework called BCube-based DCN (BDCN) that integrates the representation of the logic graphs of DCNs mentioned above, facilitating consistent algorithms' design. Then, we develop efficient algorithms to construct multiple CISTs on BDCN under the consideration of switch failures. Note that this is the first study that constructs multiple CISTs in DCNs with switch failures. Finally, using standard metrics, such as average path length (APL) and transmission failure rate (TFR), we evaluate the performance of the fault-tolerant routing through experiments.

Resource Allocation Based on Digital Twin-Enabled Federated Learning Framework in Heterogeneous Cellular Network

Federated learning (FL) allows user devices (UDs) to upload local model parameters to participate in a global model training, which protects UDs' data privacy. Nevertheless, FL still faces challenges such as core network congestion, UDs' limited resources and less efficient mapping between devices and cyber systems. Therefore, in this article, we integrate the digital twin (DT) and the mobile edge computing (MEC) technologies into a hierarchical FL framework in the heterogeneous cellular network scenario. When the UDs are not in the service range of the small base stations (SBSs), the framework allows macro base stations to assist UDs' local computation, thus reducing the transmission delay. It also protects the user privacy and allows more users to join in the training in order to improve the FL accuracy. In addition, we propose a deep reinforcement learning-based scheme to solve the joint optimization problem of dynamic UDs-stations association and resource allocation, thereby minimizing the energy consumption within a limited time delay. Simulation results show that our proposed scheme not only effectively reduces the task transmission failure rate and energy consumption compared with the baseline scheme, but also saves the communication cost through the DT network.

Performance Optimization of Surface Plasmon Resonance Imaging Sensor Network Based on the Multi-Objective Optimization Algorithm.

In this work, we report performance optimization of a wireless sensor network (WSN) based on the plain silver surface plasmon resonance imaging (SPRi) sensor. At the sensor node level, we established the refractive index-thickness models for both gold and silver in the sensor and calculated the depth-width ratio (DWR) and penetration depth (PD) values of the sensor of different gold and silver thicknesses by the Jones transfer matrix and Kriging interpolation. We optimized the DWR and PD simultaneously by using the multi-objective optimization genetic algorithm (MOGA). In the following performance optimization of WSN, we simultaneously optimized the transmission success rate and information dimension with the number of nodes and transmission failure rate of the sensor node as variables by the same algorithm. By calculating the information dimension and the transmission success rate of each Pareto optimal solution, we obtained the number of nodes and transmission failure probability of the node available for practical deployment of WSN. The above results indicate that the Pareto optimal solution set obtained from MOGA can help to provide the best solution for the optimization of some certain performance parameters and also assist us in making the trade-off decision in the structure design and network deployment if optimal values of all the performance parameters can be obtained simultaneously.

Solar node and gateway wireless system functions in record breaking polar vortex outbreak of February 2021

AbstractAdvances in environmental and agricultural management are increasingly enabled by unattended data acquisition using internet‐of‐things (IOT) approaches. These approaches combine advanced sensors and wireless data transmission to automatically convey field data to the internet. Users, either human or machine, then can access and act upon the data from nearly anywhere in the world. Particularly in the case of machines automatically acting on the data, robustness, reliability and accuracy of data are crucial to preventing unintended outcomes of machine operations and continued supply of key services. Low‐cost, low‐power, and solar‐powered systems are important to enable market entry of advanced decision support systems based on IOT data acquisition approaches. The polar vortex outbreak of February 2021 in the central United States provided an extreme test of such a node and gateway system for automatic data acquisition and telemetry to the internet over the cellular telephone network. The system, codesigned by USDA‐ARS and Acclima, performed admirably despite air temperatures reaching a minimum of −24 °C, temperatures < 0 °C for 8 d and < −7 °C for 6 d, two snowstorms, and overcast conditions. The six nodes, gateway, and 36 sensors continued to function reliably with a data transmission failure rate of <2 in 10,000 even though the Li‐ion batteries could not be recharged for 7 d due to temperatures <5 °C. The system reports geographic position of each node and gateway, model numbers and firmware versions of all equipment, including sensors, date, and time of sensor readings, and individual sensor elevations relative to a reference surface, affording data self‐identification for unfettered use by remote systems.

A protection routing with secure mechanism in Möbius cubes

The protection routing uses the multi-paths technique for integrating route discovery and route maintenance mechanisms in a network, and thus it can tolerate the failure of one component (including a node or a link). Tapolcai (2013) proposed a method showing that a network possessing two completely independent spanning trees (CISTs for short) suffices to configure a protection routing. However, it is well-known that the problem of determining whether there exist two CISTs in a graph (or network) is NP-complete. In this paper, we extend Tapolcai’s method such that the protection routing is configured by a combination of multiple CISTs. The first application of such an extension is that it can be used to deal with the problem of security in transmission, which we call the secure-protection routing scheme (SPR-scheme for short). Thus, a network transmission using the SPR-scheme ensures that no node other than the destination can receive the complete message. Moreover, we show that if a message M is transmitted in a network G using the SPR-scheme configured by a combination of n CISTs, then each intermediate node of G can receive a maximum of 2∕n ratio of M. From a similar idea of the extension, another application is the so-called multiple-protection routing scheme (MPR-scheme for short) which can be used to increase the capability of fault-tolerance. For assessing the performance of routing using MPR-scheme, we first propose a construction of three CISTs in the two types of Möbius cubes, which are hypercube-variant networks and are superior to hypercubes due to having a smaller diameter. For the n-dimensional Möbius cube, the diameters of CISTs we constructed are at most 14 when n=6 and at most 2n+1 when n⩾7. So, we configure the desired protection routing in the Möbius cubes via the three CISTs. Then, we provide simulation results to experimentally evaluate the performance of the newly proposed MPR-scheme in the n-dimensional Möbius cubes for 6⩽n⩽10. As an important point, our results show that the adoption of routing using MPR-scheme will result in a significant slowdown in the transmission failure rate.

Risk-Averse Transmission Path Selection for Secure State Estimation in Power Systems

The secure state estimation (SSE) problem is investigated for a kind of power systems where the smart meters’ measurements are transmitted to a remote estimator. In this paper, we mainly focus on the transmission via wireless networks. Taking consideration of the possible increase in transmission failure rate due to risk events, such as jamming attacks, a so-called risk-averse transmission path selection (RaTPS) method is proposed to improve SSE robustness. Based on the idea of reinforcement learning, the transmission acknowledgments are applied as the reinforcement signals to reward the source node (smart meter) for choosing more reliable paths. The multipath traffic allocation can adaptively performed according to the transmission failure rate of each path. The theoretical analysis about convergence of RaTPS and SSE is given with the technique of Markov chain, and it is illustrated in the simulation that the robustness of SSE can be improved by using RaTPS.

Sampled-data state estimation for a class of delayed complex networks via intermittent transmission

This paper investigates the sampled-data state estimation problem for a class of delayed complex networks. At certain sampling times, transmission of sampled-data through communication network may fail, which means the considered estimator can only intermittently receive sampled-data. The main objective of this paper is to design a sampled-data state estimator subjected to intermittent transmission such that the error system is exponentially stable. Specifically, the error system is first transformed into time-varying delayed switched systems, including both stable and unstable subsystems. And then, to analyze the stability of the error system, a modified Halanay inequality is presented. In view of the modified Halanay inequality and switched systems methodology, a sufficient condition for globally exponential stability of the error system is established. Meanwhile, the upper bound of transmission failure rate is given, which reflects to be closely related to sampling period and the upper bound of node delays. Furthermore, the desired estimator gain of each node is explicitly provided by solving a set of matrix inequalities. Finally, a numerical simulation is carried out to verify the effectiveness of the inferred results.

Design of Notification System Illegal Parking Vehicles on Campus

The increase in the number of private cars as well as non-standard parked behavior has brought great pressure to campus traffic. In order to control this non-standard parked behavior, orderly and reasonable guide and regulate owners to develop good parking habits, we design a vehicle parking violation notification system. A system is designed in the article to record illegal parking information of vehicles. A working principle of this system is that a wireless MMS image terminal captures image information of illegal vehicles, and real-time transmits the captured image information to the Data Center Computer in Security Department of the school through the GPRS network, so as to achieve illegal vehicle information is timely recorded and notified. Meanwhile, outside campus of illegal vehicles will be warned or limited its re-enter the campus. After a year of work and testing, the entire system is stable, and the image information transmission failure rate is very low. Illegal parking behavior on campus has been significantly curbed, and traffic order has been significantly improved.

Optimal protocol for teleconsultation with a cellular phone for dentoalveolar trauma: an in-vitro study

PurposeDental trauma is frequently unpredictable. The initial assessment and urgent treatment are essential for dentists to save the patient's teeth. Mobile-phone-assisted teleconsultation and telediagnosis for dental trauma could be an aid when a dentist is not available. In the present in-vitro study, we evaluated the success rate and time to transfer images under various conditions.Materials and MethodsWe analyzed the image quality of cameras built into mobile phones based on their resolution, autofocus, white-balance, and anti-movement functions.ResultsThe image quality of most built-in cameras was acceptable to perform the initial assessment, with the autofocus function being essential to obtain high-quality images. The transmission failure rate increased markedly when the image size exceeded 500 κB and the additional text messaging did not improve the success rate or the transmission time.ConclusionOur optimal protocol could be useful for emergency programs running on the mobile phones.

Commentary on an article by David D. Greenberg, MD, et al.: “Allograft Compared with Autograft Infection Rates in Primary Anterior Cruciate Ligament Reconstruction”

Multiple graft choices exist for surgical reconstruction of the anterior cruciate ligament. No single graft choice has been demonstrated to be superior, and graft choice should be individualized for each patient. Historically, autologous bone-patellar tendon-bone has been the most commonly used graft. The disadvantages of autologous graft include donor site morbidity, the potential for stiffness, and anterior knee pain. The use of allograft tissue for anterior cruciate ligament reconstruction has gained popularity for multiple reasons. These include less surgical morbidity, shorter operative time, easier early postoperative recovery, improved cosmesis, and the availability of larger and multiple grafts for complex or revision surgeries. The risks of allograft tissue include disease transmission, immune reaction, slower incorporation, and higher failure rate. Despite the fact that postoperative infection following any anterior cruciate ligament reconstruction is a serious complication, there is a paucity of reports concerning the risk of infection related to the choice of graft. Fortunately, the transmission of viral or bacterial infection by allograft tissue has been fairly rare. There have been one reported case of HIV transmission and two cases of hepatitis-C transmission by bone-patellar tendon-bone allografts1. The risk of bacterial infection transmitted through the use of allograft tissue received national attention when fourteen cases of patients with an allograft-associated Clostridium infection, including one death, were reported over a four-year period from 1998 to 2002. All fourteen grafts had been processed by a single tissue bank2. The article entitled “Allograft Compared with Autograft Infection Rates in Primary Anterior Cruciate Ligament Reconstruction,” by Greenberg et al., addresses a very timely question. Historically, the prevalence of septic arthritis after anterior cruciate ligament surgery has been reported to range from 0.2% to 4.0%3. Synthetic grafts and hamstring grafts have been more commonly involved. With the increased use of allograft tissue and at least one known cluster of allograft-associated bacterial infections, it is important to determine if allograft use in anterior cruciate ligament surgery exposes a patient to a greater risk of septic arthritis. Greenberg et al.’s study is a Level-II combined prospective and retrospective multicenter cohort study of 861 patients undergoing primary anterior cruciate ligament surgery with use of autograft or allograft tissue. The allografts were obtained from a single tissue bank that used aseptic processing and low dose irradiation. A single dose of antibiotics was given intravenously preoperatively, and no drains were used postoperatively. No deep infection was identified in any of the 861 patients. Statistical analysis of the fact that there was no case of septic arthritis in either group indicated a 95% confidence interval of 0% to 0.57% for the allograft group and 0% to 1.66% for the autograft group. The overall rate of superficial infections was 2.32%. There was no statistical difference between the two groups. The results of this study are reassuring for orthopaedic surgeons using allograft tissue obtained from an accredited tissue bank. They are also consistent with those of a recent, similar, well-powered study by Barker et al.4 The risk of an immune reaction leading to allograft failure after anterior cruciate ligament reconstruction appears to be extremely low, and, to my knowledge, no report documenting this potential complication has been published in the literature. Long-term follow-up and future studies will even better define the role of allografts in anterior cruciate ligament surgery and the potential problems that may be associated with allograft use.

Binomial parameters differ across neocortical layers and with different classes of connections in adult rat and cat neocortex

Binomial model-based analysis compared excitatory connections involving different classes of neurons in different neocortical layers. Single-sweep excitatory postsynaptic potentials (EPSPs) from dual intracellular recordings in adult cat and rat slices were measured. For data subsets corresponding to first EPSPs exhibiting different degrees of posttetanic potentiation and second, third etc. EPSPs in trains at different interspike intervals, coefficient of variation (CV), transmission failure rates (F), variance (V), and V/M were plotted against mean EPSP amplitude (M). Curves derived from binomial models in which subsets varied only in p (release probability) were fit and parameters q (quantal amplitude), and n (number of release sites) were estimated. Estimates for q and n were similar for control subsets and subsets recorded during Ca(2+) channel blockade, only p varied. Estimates from the four methods were powerfully correlated, but when CV, F, V, and V/M were plotted against M, different types of connections occupied different regions of parameter space. Comparisons of linear fits to V/M against M plots and of parameter estimates indicated that these differences were significant. Connections between pyramids in different layers and inputs to different cell classes in the same layer differed markedly. Monte Carlo simulations of more complex models subjected to simple binomial model-based analysis confirmed the significance of these differences. Binomial models, either simple, in which p and q are identical at all terminals involved, or more complex, in which they differ, adequately describe many neocortical connections, but each class uses different combinations of n, mean p, and mean q.

Multi-unit spike-triggered averaging: a method for probing the physiology of central synapses

We describe the ongoing development of a method that combines multi-unit extracellular recording with intracellular recording to probe unitary synaptic connections in the central nervous system. In multi-unit spike-triggered averaging (multi-unit STA), intracellular recordings are averaged based on extracellularly recorded action potentials from multiple units to rapidly screen large numbers of neuronal pairs for rare synaptic connections. High throughput is achieved by using many extracellular electrodes and online, automated analysis. Using this approach, we were able to screen dozens of candidate pairs per hour. About 1–2% of these were synaptically connected, and for some of these presynaptic unit isolation was sufficient to accurately quantify synaptic properties such as latency, conductance, kinetics and transmission failure rate. Since it requires only a single intracellular recording, multi-unit STA might be a suitable method for probing unitary synaptic connections in the intact brain, where obtaining multiple intracellular recordings is not feasible.

Pre- and postsynaptic properties of somatic and dendritic inhibition in dentate gyrus

We compared somatic and dendritic inhibition in paired recordings from two classes of anatomically identified interneurons and granule cells of the dentate gyrus. Inhibitory postsynaptic current (IPSC) amplitude and decay were remarkably similar at somatic and dendritic synapses. Slower IPSC rise times and longer latencies at dendritic synapses were consistent with their distal location, without requiring differences in postsynaptic γ-aminobutyric acid type A (GABA A) receptor properties. In contrast, higher transmission failure rate and greater paired-pulse depression at dendritic synapses suggest that somatic and dendritic inhibition differ in presynaptic properties. Cholinergic input has been suggested to modulate hippocampal rhythmicity as well as episodic memory function. We therefore tested the effects of acetylcholine (ACh) on paired IPSCs and on spontaneous synaptic activity in interneurons and granule cells. We found no effect of ACh on paired IPSCs; however, spontaneous IPSCs recorded in granule cells were enhanced in amplitude and frequency. ACh potentiated spontaneous excitatory postsynaptic potentials (sEPSPs) and induced spiking in both types of interneuron, and preferentially increased sEPSP frequency in dendritic interneurons. Our findings suggest that patterns of activity in the two classes of interneurons, coupled with differences in their presynaptic properties, are likely to determine the roles of somatic and dendritic inhibition in network function.

Transmission failure rate for computed tomography examinations in a filmless imaging department

The purpose of the study was to determine the frequency and causes of unsuccessful computed tomography (CT) transmissions in a filmless imaging department and to determine the added efficiency gains provided by the sequential addition of modality worklist software and a major network upgrade. Prospective data on CT transmission error rates were recorded over an 18-month period. During the study interval, modality worklist functionality was added, followed by a network upgrade. Failed transmissions were categorized as to the source of the error (human v technical), and the specific problem encountered. Prior to the introduction of modality worklist software, the initial CT transmission failure rate was 7.6%, which was primarily the result of human error (69%), in the form of data entry error. Upon the introduction of modality worklist software, the transmission failure rate decreased to 3.5%, with human error accounting for only 16% of all failed transmissions. The subsequent addition of a network upgrade from shared Ethernet to switched Ethernet further reduced the transmission failure rate to 2.0%, which was believed to be the result of a reduction in the number of network collisions. Other sources of failed transmission occur at the levels of the CT scanner (network interface card), picture archiving and communication system (PACS)/hospital information system (HIS) interface, and modality gateway. When planning the transmission from film-based to filmless operation, one should consider various hardware, software, and infrastructural requirements to ensure successful PACS implementation. Software upgrades, in the form of modality worklist software, serve to improve technologist productivity by minimizing data entry error. Infrastructural changes, in the form of network upgrading, ensure proper dissemination of electronic data with decreased frequency of network collisions. Collectively, these improvements lead to enhanced transmission of digital images, resulting in productivity gains within the filmless CT department.

ACTH and neuromuscular transmission: Electrophysiological in vitro investigation of the effects of corticotropin and an ACTH fragment on neuromuscular transmission

AbstractThe effects of corticotropin (ACTH) and the polypeptide fragment ACTH 4‐10 on neuromuscular transmission were studied in rat phrenic nerve–diaphragm preparations in vitro. ACTH decreased the quantum content of end‐plate potentials (epps) and increased the transmission failure rate. The frequency of miniature end‐plate potentials (mepps) was increased. The results indicate that ACTH acts directly on the presynaptic terminal. The findings could explain the transient decrease in muscle strength often observed during corticotropin therapy for myasthenia gravis, and they suggest that the therapeutic effect of ACTH is indirectly mediated. The only marked effect produced by the ACTH fragment was an increase in the mepp frequency; quantum content and failure rate of epps remained unchanged. Since ACTH 4‐10 is unable to stimulate cortisone release, its clinical efficacy seems unlikely.