Interruption Probability Research Articles

Optimized Adaptive Streaming of Multi-video Stream Bundles

In contrast to traditional video, multi-view video streaming allows viewers to interactively switch among multiple perspectives provided by different cameras. One approach to achieve such a service is to encode the video from all of the cameras into a single stream, but this has the disadvantage that only a portion of the received video data will be used, namely that required for the selected view at each point in time. In this paper, we introduce the concept of a “multi-video stream bundle” that consists of multiple parallel video streams that are synchronized in time, each providing the video from a different camera capturing the same event or movie. For delivery we leverage the adaptive features and time-based chunking of HTTP-based adaptive streaming, but now employing adaptation in both content and rate. Users are able to change their viewpoint on-demand and the client player adapts the rate at which data are retrieved from each stream based on the user's current view, the probabilities of switching to other views, and the user's current bandwidth conditions. A crucial component of such a system is the prefetching policy. For this we present an optimization model as well as a simpler heuristic that can balance the playback quality and the probability of playback interruptions. After analytically and numerically characterizing the optimal solution, we present a prototype implementation and sample results. Our prefetching and buffer management solution is shown to provide close to seamless playback switching when there is sufficient bandwidth to prefetch the parallel streams.

The Effect of Power Adjustment on Handover in High-Speed Railway Communication Networks

In future 5G communication systems, supporting high-quality wireless communications in high-mobility scenarios becomes very essential. Although many existing works indicate that increasing transmit power is able to reduce the handover failure probability (referred to as the power greedy scheme) through improving the radio condition or received signal strength, it goes against the requirement of green system design. In this paper, we investigate the effect of power adjustment on handover performance from the perspective of reducing the “uncertainty” in handover procedure in high-speed railway communications systems by embedding it into the existing handover procedure. It is shown that, with power adjustment, the handover performance can be improved without increasing extra energy consumption. The power adjustment-assisted handover scheme is applied to a high-speed railway scenario with distributed antenna system (DAS) cells. Both the blanket transmission-based handover scheme and the remote antenna unit selection transmission-based handover scheme are discussed for DAS cells. To evaluate the performance, the handover probability, handover failure probability, and communication interruption probability associated with two handover schemes are analyzed. Moreover, two new performance metrics, named handover occurrence probability and handover failure occurrence probability, are defined to efficiently evaluate the handover performance versus the position of the train. Both the analytical and the numerical results show that introducing power adjustment into handover gives ability to achieve a better performance compared with the current existing ones. Moreover, the power adjustment-assisted handover scheme is capable of achieving the similar system performance to existing power greedy scheme but without increasing energy consumption.

Cognitive radio networks with multiple secondary users under two kinds of priority schemes: Performance comparison and optimization

In this paper, we consider a cognitive radio network with multiple Secondary Users (SUs). The SU packets generated from the SUs are divided into SU1 packets and SU2 packets, and the SU1 packets have higher priority than the SU2 packets. Different from the conventional preemptive priority scheme (called Scheme Ⅰ), we propose a non-preemptive priority scheme for the SU1 packets (called Scheme Ⅱ) to guarantee the transmission continuity of the SU2 packets. By constructing a three-dimensional Markov chain, we give the transition probability matrix of the Markov chain, and obtain the steady-state distribution of the system model. Accordingly, we derive some performance measures, such as the channel utilization, the blocking probability of the SU1 packets, the interruption probability of the SU1 packets and the SU2 packets, the normalized throughput of the SU1 packets, and the average latency of the SU2 packets. Moreover, we provide numerical experiments to compare different performance measures between the two priority schemes. Finally, we show and compare the Nash equilibrium strategy and the socially optimal strategy for the SU2 packets between Scheme Ⅰ and Scheme Ⅱ.

Analysis of secondary user performance in cognitive radio networks with reactive spectrum handoff

Cognitive radio networks use dynamic spectrum access of secondary users (SUs) to deal with the problem of radio spectrum scarcity . In this paper, we investigate the SU performance in cognitive radio networks with reactive-decision spectrum handoff. During transmission, a SU may get interrupted several times due to the arrival of primary (licensed) users. After each interruption in the reactive spectrum handoff, the SU performs spectrum sensing to determine an idle channel for retransmission. We develop two continuous-time Markov chain models with and without an absorbing state to study the impact of system parameters such as sensing time and sensing room size on several SU performance measures. These measures include the mean delay of a SU, the variance of the SU delay, the SU interruption probability, the average number of interruptions that a SU experiences, the probability of a SU getting discarded from the system after an interruption and the SU blocking probability upon arrival.

An Optimized Seamless Dual-Link Handover Scheme for High-Speed Rail

In high-speed rail (HSR) with Long-Term Evolution (LTE) technology, the wireless communication quality of service (QoS) is enormously degraded because of the unstable signal and frequent handover. Recently, a seamless handover using two antennas on the top of a train has been introduced to provide a better user experience. The two antennas are mounted on the front and the rear of the train, respectively, so that one performs handover, and the other is communicating. A bicasting mechanism is adopted to eliminate the delay and overhead of data forwarding. In this paper, we consider a new algorithm to optimize the handoff opportunity by investigating not only the hysteresis exceeding level but the signal strength of both antennas as well. The parameter selection in the algorithm is analyzed based on a probability model. Furthermore, a set of new handover procedures, which optimize the utilization of the two antennas, is proposed to decrease the overhead and improve the QoS of the users. Accordingly, numerical results show that the handover failure probability (HFP) and the communication interruption probability (CIP) are both obviously reduced.

The effect of interruption probability in lattice model of two-lane traffic flow with passing

A new lattice model is proposed by taking into account the interruption probability with passing for two-lane freeway. The effect of interruption probability with passing is investigated about the linear stability condition and the mKdV equation through linear stability analysis and nonlinear analysis, respectively. Furthermore, numerical simulation is carried out to study traffic phenomena resulted from the interruption probability with passing in two-lane system. The results show that the interruption probability with passing can improve the stability of traffic flow for low reaction coefficient while the interruption probability with passing can destroy the stability of traffic flow for high reaction coefficient on two-lane highway.

Spectrum Handoff Method Based on Extenics for Cognitive Radio Sensor Networks

A spectrum handoff model and optimal channel decision method based on Extenics have been proposed in order to resolve the optimal channel decision problem of spectrum handoff in Cognitive Radio Sensor Networks. The method of matter-element Extenics is used to analyses the spectrum handoff process. The channel state through the spectrum sensing and status information of the primary users is analyzed and transformed by matter-element Extenics. Then the parameters to determine the best channel are calculated on the basis of Extenics correlation function. Finally the optimal channel is selected. The simulation results show that the proposed method can improve spectrum utilization efficiency of Cognitive Radio Sensor Networks and can reduce the interrupt probability of second users.

INTERRUPTED BINARY MASS TRANSFER IN STAR CLUSTERS

ABSTRACT Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters ( ≲ 10 4 ?> M ⊙ ?> ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect ≪ 1 % ?> to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ∼2.

A dynamic sourcing strategy considering supply disruption risks

This study presents a formulation that supports decision-making by determining the optimal number of standby suppliers required to respond to supply failure risks. The problem of supply failure is modelled through a standby approach, in which failure is time-dependent. The probabilities of supply interruption, financial loss caused by supply failure, and operating cost of working with suppliers are modelled to yield the expected total cost, which enables organisations to determine the optimal number of suppliers. Two possible modes of substitution failure are considered in the standby model to enhance the analysis. A set of sensitivity analyses are performed for several input parameters to illustrate the model’s behaviour. The analysis provides an optimal sourcing strategy depending on a combination of supply risk, operational cost vs. loss ratio and length of the supply period. The proposed model indicates the benefits of cost savings, unlike other dynamic models that use multiple suppliers simultaneously.

A Machine Learning Based Approach to Control Network Activity

A Machine Learning Based Approach to Control Network Activity

Special Issue on Sustainable Civil Infrastructures: Innovative Technologies and Materials

Special Issue on Sustainable Civil Infrastructures: Innovative Technologies and Materials

Study of a Computer-Based Control System with Fault-Tolerant and Fail-Safe Behavior

Abstract The software and hardware of Safety Critical Systems - SCS, which control special critical technology process or operation, are subject of enhanced requirements for reliability and inadmissibility of any incorrect controlling influences (safety) after failures. This paper suggests and investigates a hybrid computerbased fail-safe/fault-tolerance FST-structure with single reservation, which has the qualities to meet these requirements. The base system 2 ∨ 2, based on which it is built, is studied in the previous edition of Information Technjlogies and Control. For derivation of probabilistic models through which to establish the efficiency of the strutucral redundancy in a fault-tolerant structure, in this paper are used the published results. Formulas are derived for the probability of failure-free operation (availability coefficient), for safe failure and for unidentified (dangerous) failure. Models are found for calculation of the enhancement of reliability and the variation of safety relative to the base system 2 ∨ 2. Subject of analysis are type software and hardware modifications of the proposed general scheme used in the practice of different companies, which manufacture and operate SCSs. It is proven that at the expense of acceptable hardware redundancy and insignificant increase of dangerous failures the probability of interruption of the operation of the FST- system and its down-time due to failure may decrease by tenths of thousands of times.

Influence of the traffic interruption probability on traffic stability in lattice model for two-lane freeway

In this paper, a new lattice model is proposed with the traffic interruption probability term in two-lane traffic system. The linear stability condition and the mKdV equation are derived from linear stability analysis and nonlinear analysis by introducing the traffic interruption probability of optimal current for two-lane traffic freeway, respectively. Numerical simulation shows that the traffic interruption probability corresponding to high reaction coefficient can efficiently improve the stability of two-lane traffic flow as traffic interruption occurs with lane changing.

Strategy decision of business interruption insurance and emergency supply strategy based on supply disruptions

Purpose: Recent years have witness the pervasive supply disruptions and their impacts on supply chain performance. It is significant for enterprises to adopt comprehensive measures to cope with supply disruptions. The purpose of this study is to investigate how BI insurance make up the shortage of emergency supply and affect the expected profit of enterprises. Design/methodology: This study develops the penalty cost function on the basic of the financial costs caused by the interruption losses, introduces variables of BI insurance and operational measures, establishes the profit model with BI insurance or not. Findings: Through the proof and analysis, it is demonstrated that BI insurance can mitigate the adverse effect of the increasing cost for expected profit. And this study finds that the value of BI insurance is higher when interruption probability is lower and penalty coefficient is higher. Originality/value: In this study, it is investigated that the impact of business interruption (BI) insurance on supply disruptions and its complementary value against the higher purchase cost of emergency sourcing strategy. BI insurance is an efficient measure for supply interruption and should be adopted correctly to play a role in managing supply disruption risk.

Methodology for analyzing risk at nuclear facilities

A methodology for evaluating risks at nuclear facilities is developed in this work. A series of measures is drawn from the analysis of factors that determine risks. Five measures are created to evaluate risks at nuclear facilities. These include the legal and institutional framework, material control, physical protection system effectiveness, human resources, and consequences. Evaluation attributes are developed for each measure and specific values are given in order to calculate the risk value quantitatively. Questionnaires are drawn up on whether or not a state has properly established a legal and regulatory framework (based on international standards). These questionnaires can be a useful measure for comparing the status of the physical protection regime between two countries. Analyzing an insider threat is not an easy task and no methodology has been developed for this purpose. In this study, attributes that could quantitatively evaluate an insider threat, in the case of an unauthorized removal of nuclear materials, are developed by adopting the Nuclear Material Accounting & Control (NMAC) system. The effectiveness of a physical protection system, P(E), could be analyzed by calculating the probability of interruption, P(I), and the probability of neutralization, P(N). In this study, the Tool for Evaluating Security System (TESS) code developed by KINAC is used to calculate P(I) and P(N). Consequence is an important measure used to analyze risks at nuclear facilities. This measure comprises radiological, economic, and social damage. Social and economic damages are difficult to evaluate. Therefore, radiation levels and theft of nuclear materials that could be quantified are adopted as attributes for analyzing the consequences. Awareness of the nuclear security culture and physical protection resources such as staffing, capabilities, and cost required to provide PP should be considered when evaluating risks. In this study, these attributes are included in the measure of human resources. Human resources include such factors as trustworthiness, degree of nuclear security culture awareness, and frequency of psychiatric testing of employees. A case study performed on hypothetical facilities demonstrates that the developed methodology could be used to analyze innovative nuclear systems as well as existing facilities.

A new lattice model with the consideration of the traffic interruption probability for two-lane traffic flow

In this paper, we proposed a new lattice model of two-lane traffic flow considering the effects of traffic interruption probability. The stability condition is deduced from the linear stability analysis for two-lane freeways. Also, the modified Korteweg–de Vries equation is obtained to describe the traffic phase transition resulted from traffic interruption probability through nonlinear analysis in two-lane system. The numerical simulation results validate that the traffic interruption probability further improves the stability of traffic flow on two-lane freeways.

Probability of Road Interruption due to Landslides under Different Rainfall-Return Periods Using Remote Sensing Techniques

AbstractHeavy rainfall-induced landslides along mountain routes in Taiwan easily cause road interruption, especially under extreme rainfall conditions. Road interruption due to rainfall-induced landslides is a major problem for Taiwanese authorities. In this study, remote sensing data, including satellite images and aerial photos, were employed to interpret landslides, which were mapped using geographical information systems (GISs). The goal was an event-based landslide inventory. Causative and triggering factors for landslides were adopted in a logistic model to predict landslide occurrence. These factors included lithology, normalized difference vegetation index, slope gradient, slope roughness, maximum elevation, total curvature, total slope height, maximum hourly rainfall, and total accumulated rainfall. With the proposed landslide prediction model, the probability of road interruption due to rainfall-induced landslides was evaluated under different rainfall-return periods. The model was confirmed by ...

Export Survival in Global Production Chains

AbstractIn this paper, we examine the survival capacity of trade relationships in cross‐border production chains. Our main contribution is to show that there are differences in the probability of export interruption between intermediate and final stages along the global value chain, finding a lower sensitivity of intermediate goods to the increasing competition from lower‐income countries. In addition, the paper also makes a methodological contribution by using time‐discrete duration models with product‐country random effects to control for unobservable heterogeneity and by including interactions in the model, in order to identify the sources of these differences. Our estimates show that variables such asEUmembership, export experience, product and market diversification, initial trade value, destination market size, geographical proximity and economic proximity reduce the likelihood of export failure more for intermediate than for final goods, being the differential impact particularly higher for the two first variables. These results would suggest that factors that reduce uncertainty and search costs and increase trust and reliability among production partners are particularly relevant for intermediate stages, fostering the probability of remaining an active member of global production chains.

Impact of the traffic interruption probability of optimal current on traffic congestion in lattice model

In this paper, a new lattice model is proposed with the consideration of the traffic interruption probability of the optimal current. The linear stability condition is obtained by linear stability analysis and the mKdV equation is deducted from nonlinear analysis via considering the traffic interruption probability of the optimal current, respectively. The results of numerical simulation show that the traffic interruption probability of the optimal current can efficiently suppress traffic jams under high response coefficient and deteriorate traffic situations under low response coefficient.

A competing risk analysis of hormone therapy interruption in Asian women with breast cancer.

This study aimed to use a competing risk approach to evaluate the probability of the occurrence of hormone therapy (HT) interruption and to assess its associated predictors in Asian women with breast cancer. This retrospective cohort study used the Taiwan Health Insurance Research Database from 2003 to 2011. Reimbursement data for women with newly diagnosed primary breast cancer were extracted. Interruption (gap ≥ 180 days) and time to first interruption of HT were identified. The probability of interruption was analysed by Kaplan-Meier (KM) method and cumulative incidence competing risk (CICR) method. Competing risk regressions were used to assess the predictors of interruption. The 5-year cumulative incidence of first HT interruption was 14% versus 13% estimated by the KM and the CICR methods, respectively. The estimated incidences from CICR method tended to be around 11% lower than KM method in various HT utilization patterns. Younger (≤50 years) age at diagnosis, switching HT and the presence of HT-related adverse events were identified as predictors of interruption in competing risk regressions. The competing risk approach provided lower probabilities and estimates when investigating the incidence of first interruption than the standard survival analysis. The competing risk method, which takes into account the competing risks from cancer recurrence and death, should be considered in future analysis. In terms of improving persistence of HT, it is important to focus on patients of younger age at diagnosis, HT switching and experiencing adverse events.