Temporal Violations Research Articles

Humans predict the forest, not the trees: statistical learning of spatiotemporal structure in visual scenes.

The human brain is capable of using statistical regularities to predict future inputs. In the real world, such inputs typically comprise a collection of objects (e.g. a forest constitutes numerous trees). The present study aimed to investigate whether perceptual anticipation relies on lower-level or higher-level information. Specifically, we examined whether the human brain anticipates each object in a scene individually or anticipates the scene as a whole. To explore this issue, we first trained participants to associate co-occurring objects within fixed spatial arrangements. Meanwhile, participants implicitly learned temporal regularities between these displays. We then tested how spatial and temporal violations of the structure modulated behavior and neural activity in the visual system using fMRI. We found that participants only showed a behavioral advantage of temporal regularities when the displays conformed to their previously learned spatial structure, demonstrating that humans form configuration-specific temporal expectations instead of predicting individual objects. Similarly, we found suppression of neural responses for temporally expected compared with temporally unexpected objects in lateral occipital cortex only when the objects were embedded within expected configurations. Overall, our findings indicate that humans form expectations about object configurations, demonstrating the prioritization of higher-level over lower-level information in temporal expectation.

Modeling Pedestrian Temporal Violations at Signalized Crosswalks: A Random Intercept Parametric Survival Model

This study aims to model pedestrian temporal violation behavior at signalized crosswalks. Video data of pedestrian crossing behavior were collected from three locations in China and were used to investigate the effect of several factors on pedestrian temporal violation behavior. The temporal violation behavior was analyzed using the relationship between pedestrian waiting duration and their endurance probabilities. A fully parametric duration model with Weibull distribution was used to model the temporal violation behavior, and the cluster-specific heterogeneity among the three study sites was accounted for using random intercepts. Six variables were identified to significantly affect the violation behavior: pedestrian gender and phone distraction status, location type, pedestrian volume, day of the week, and time of the day. The results show that pedestrians are likely to disobey traffic regulations when there are longer waiting durations. Male pedestrians have a higher violation tendency than females. Pedestrians distracted by their phones have longer waiting durations than undistracted pedestrians. Signalized road segment crosswalks are associated with higher temporal violation propensity than signalized intersection crosswalks. Pedestrians are more likely to commit violations at higher pedestrian densities. Weekdays are associated with shorter waiting durations and higher violation tendency than weekends. Pedestrians are more likely to violate traffic regulations in the morning than at midday and in the evening. These findings give insights into the pedestrian crossing behavior to better accommodate pedestrians and improve safety.

Altered event processing in persons with Parkinson's disease.

Persons with Parkinson's disease (PD) often show particular problems in seemingly simple routines despite relatively preserved cognitive function. We therefore investigated the processing of everyday events on behavioral and neurophysiological levels in a PD and control group. The participants had to indicate via button press whether three sequentially presented sub-events described a previously defined event (e.g., going grocery shopping). Sub-event sequences were either correct or included an event that did not belong to the event (content violation), or events were chronologically wrong (temporal violation). During task execution event-related potentials (ERPs) were recorded. Generally, the PD group showed less accurate performance independently from task conditions, and reaction times to temporal violations were particularly slow compared to the control group. Regarding ERP results, the control group showed a right lateralized N400 effect in response to content violations, which was absent in the PD group indicating altered content event processing. Concerning the reanalysis of content event violations, the expression of late positive components (LPCs) was similar between both groups. Upon temporal violations, both groups also showed a LPC with a tendentially earlier onset in the PD group, resembling positive components indicative of novelty processing. Together, these findings suggest poor event prediction in PD, which may originate from weak event representation or retrieval and possibly relate to prevalent behavioral dysfunctions in everyday life in PD.

The human brain processes hierarchical structures of meter and harmony differently: Evidence from musicians and nonmusicians.

The processing of temporal structure has been widely investigated, but evidence onhow the brain processes temporal and nontemporal structures simultaneously is sparse. Using event-related potentials (ERPs), we examined how the brain responds to temporal (metric) and nontemporal (harmonic) structures in music simultaneously, and whether these processes are impacted by musical expertise. Fifteen musicians and 15 nonmusicians rated the degree of completeness of musical sequences with or without violations in metric or harmonic structures. In the single violation conditions, the ERP results showed that both musicians and nonmusicians exhibited an early right anterior negativity (ERAN) as well as an N5 to temporal violations ("when"), and only an N5-like response to nontemporal violations ("what"), which were consistent with the behavioral results. In the double violation condition, however, only the ERP results, but not the behavioral results, revealed a significant interaction between temporal and nontemporal violations at a later integrative stage, as manifested by an enlarged N5 effect compared to the single violation conditions. These findings provide the first evidence that the human brain uses different neural mechanisms in processing metric and harmonic structures in music, which may shed light on how the brain generates predictions for "what" and "when" events in the natural environment.

Self-Stabilizing Secure Computation

Self-stabilization refers to the ability of systems to recover after temporal violations of conditions required for their correct operation. Such violations may lead the system to an arbitrary state from which it should automatically recover. Typically, a self-stabilizing algorithm is examined for eventual functionality, namely, whether the algorithm eventually exhibit the desired input output relation. In this article, we extend the typical functionality criteria to include the recovery of privacy and security aspects. In cryptographic protocol problems, two or more parties want to perform some joint computation, while guaranteeing security properties against adversarial behavior. Current cryptographic protocols guarantee these security properties as long as the adversary is limited to compromise only a fraction of the parties. However, in reality, the adversary may compromise all the parties of the system for a while. We introduce the notion of Self-Stabilizing Secure Computation, a design that ensures that the security properties of computation are automatically regained, even if at some point the entire system is compromised. We then propose a self-stabilizing secure protocol for the evaluation of a reactive functionality which yields a computation of a virtual global finite state machine.

Dynamic Monitoring of Service Outsourcing for Timed Workflow Processes

Service outsourcing for workflow processes has drawn much attention from researchers in recent years. Service outsourcing can not only improve the execution efficiency of workflow processes, but also reduce the overall costs and risks effectively. However, the existing methods neglect to consider the dynamic monitoring of the temporal constraints and the data transferring relationship of the activities among the local subplans or subprocesses of service providers in service outsourcing. As a result, the existing methods cannot propose solutions to temporal violations. In this paper, we propose a Petri net-based approach for dynamic monitoring of the temporal constraints of service outsourcing for timed workflow processes. As a widely used formal tool for modeling and analyzing the workflow processes, Petri nets can be used to design the structure of the workflow processes and provide powerful analysis techniques to verify the constraints. Specifically, we first propose a procedure to construct the Petri net-based fragments with data transferring of workflow processes. The monitoring mechanism of the temporal constraints is then set based on the fragments. Finally, we present algorithms for dynamically verifying the temporal constraints during the execution of fragments and repairing the temporal violations on the fragments. Compared with the existing methods, the proposed approach can construct fragments based on arbitrary service outsourcing results and provide optimal solutions to resolving temporal violations. Accordingly, the proposed approach can improve the efficiency of the exception handling in the workflow processes and reduce the overall operational costs.

Effects of Handshake Duration on Other Nonverbal Behavior.

Although detailed descriptions of proper handshakes partly comprise many etiquette books, how a normal handshake can be described, its proper duration, and the consequences of violating handshake expectations remain empirically unexplored. This study measured the effect of temporal violations of the expected length of a handshake (less than three seconds according to previous studies) administered unobtrusively in a naturalistic experiment. We compared volunteer participants' (N = 34; 25 females; 9 males; Mage = 23.76 years, SD = 6.85) nonverbal behavior before and after (a) a prolonged handshake (>3 seconds), (b) a normal length handshake (average length <3 seconds), and (c) a control encounter with no handshake. Frame-by-frame behavioral analyses revealed that, following a prolonged handshake (vs. a normal length or no handshake), participants showed less interactional enjoyment, as indicated by less laughing. They also showed evidence of anxiety and behavioral freezing, indicated by increased hands-on-hands movements, and they showed fewer hands-on-body movements. Normal length handshakes resulted in less subsequent smiling than did prolonged handshakes, but normal length handshakes were also followed by fewer hands-on-face movements than prolonged handshakes. No behavior changes were associated with the no-handshake control condition. We found no differences in participants' level of empathy or state/trait anxiety related to these conditions. In summary, participants reacted behaviorally to temporal manipulations of handshakes, with relevant implications for interactions in interviews, business, educational, and social settings and for assisting patients with social skills difficulties.

Sensory loss enhances multisensory integration performance

Auditory and visual sensory loss has repeatedly been shown to alter abilities in remaining sensory modalities. It is, however, unclear whether sensory loss also impacts multisensory integration; an ability that is fundamental for the perception of the world around us. We determined effects of olfactory sensory deprivation on multisensory perception by assessing temporal as well as semantic aspects of audio-visual integration in 37 individuals with anosmia (complete olfactory sensory loss) and 37 healthy, matched controls. Participants performed a simultaneity judgement task to determine the temporal binding window, and a multisensory object identification task with individually degraded, dynamic visual, auditory, and audio-visual stimuli. Individuals with anosmia demonstrated an increased ability to detect multisensory temporal asynchronies, represented by a narrowing of the audio-visual temporal binding window. Furthermore, individuals with congenital, but not acquired, anosmia demonstrated indications of greater benefits from bimodal, as compared to unimodal, stimulus presentation when faced with degraded, semantic information. This suggests that the absence of the olfactory sense alters multisensory integration of remaining senses by sharpening the perception of cross-modal temporal violations, independent of sensory loss etiology. In addition, congenital sensory loss may further lead to increased gain from multisensory, compared to unisensory, information. Taken together, multisensory compensatory mechanisms at different levels of perceptual complexity are present in individuals with anosmia.

Temporal impact analysis and adaptation for service-based systems

Temporality is an influential aspect of service-based systems (SBS). Inability of a service to achieve time requirements may lead to violation of service-level agreements (SLA's) in a SBS. Such non-conformity by a service may introduce temporal inconsistency between dependent services and the composition. The temporal impact of the anomaly on related services and also the composition will need to be identified if SLA violations have to be rectified. Existing studies concentrate on impact analysis due to web service evolution or changes to a web service. There is a huge lacunae regarding studies on impact of time delay on temporal constraints of dependent services and obligations of business process. Although reconfiguration of SBS to overcome failures is extensively addressed, reconfiguration triggered due to temporal delay is not well explored. In this study, we try to fill the gap between reconfiguration and impact analysis invoked due to temporal violations. Once the impacted region and the amount of temporal deviation to the business process are known, we try recovery by localising the reconfiguration of services to the impacted zone.

Temporal impact analysis and adaptation for service-based systems

Temporality is an influential aspect of service-based systems (SBS). Inability of a service to achieve time requirements may lead to violation of service-level agreements (SLA's) in a SBS. Such non-conformity by a service may introduce temporal inconsistency between dependent services and the composition. The temporal impact of the anomaly on related services and also the composition will need to be identified if SLA violations have to be rectified. Existing studies concentrate on impact analysis due to web service evolution or changes to a web service. There is a huge lacunae regarding studies on impact of time delay on temporal constraints of dependent services and obligations of business process. Although reconfiguration of SBS to overcome failures is extensively addressed, reconfiguration triggered due to temporal delay is not well explored. In this study, we try to fill the gap between reconfiguration and impact analysis invoked due to temporal violations. Once the impacted region and the amount of temporal deviation to the business process are known, we try recovery by localising the reconfiguration of services to the impacted zone.

Model checking of timed compatibility for mediation-aided web service composition: A three stage approach

Currently, modeling and analyzing timed compatibility of Petri net based mediation-aided Web service composition by model checking are attracting increasing attention in the expert and intelligent systems community. However, existing methods cannot handle mediation-aided Web service composition involving complex mediation transitions, suffer from low efficiency owing to the larger size of time automata (TA) models, or are unable to automatically check temporal constraints whose activities do not include exchanged messages by observing TA. In this paper, we present a novel three-stage approach for analyzing timed compatibility of mediation-aided Web service composition via model checking. First, stage 1 treats each service in Petri net based mediation-aided Web service composition as a fragment. Second, stage 2 transforms fragments into a time automata net (TAN) based on structure transformation and interactive message transformation. Finally, stage 3 checks all types of temporal constraints. The main impact of our approach on expert and intelligent systems involves the following aspects: 1) mediation-aided service composition with complex mediation transitions can be dealt with; 2) compact TAN can be constructed for fragments in which the number of states and arcs is dramatically decreased and the verification time is extremely reduced compared with existing methods; and 3) temporal constraints whose activities have or do not have exchanged messages can be located in TAN. The main significance of our approach in the field of expert and intelligent systems is that it can greatly reduce the risk of making business decisions and the cost of handling temporal violations, and improves the innovation capability of enterprises.

A sufficient and necessary temporal violation handling point selection strategy in cloud workflow

To deliver high QoS (quality of service) for business process participants, workflow temporal verification is conducted to provide satisfactory on-time completion rate of business process in the cloud. Temporal violation handling is the last task in a typical workflow temporal verification framework to deal with detected time delays. However, there are very few existing studies regarding temporal violation handling for cloud business workflows. In this paper, queuing theory is first employed to simulate time features of parallel workflow instances. Then, propagation effect based temporal consistency model for business workflows and temporal consistency model for workflow activities in the same queuing system are presented respectively. Finally, a promising temporal violation handling point selection strategy for cloud business workflows is proposed and proved to satisfy the property of sufficiency and necessity. Compared with other representative strategies, experimental results show that our novel handling point selection strategy can reduce the monitoring and handling cost while maintaining the target on-time completion rate agreed between users and service providers.

Predicting temporal violations for parallel business cloud workflows

SummaryWorkflow temporal violations, namely, intermediate workflow runtime delays, often occur and have a serious impact on the on‐time completion of massive concurrent requests. Therefore, accurate prediction of cloud workflow temporal violations is critical as its result can serve as an essential reference for temporal violation prevention and handling strategies. Conventional studies mainly focus on the time delays of a single workflow activity or a single workflow instance but overlook the propagation of time delays among them. This is a serious problem as time delays can propagate in cloud workflow system due to resource sharing and the dependencies among workflow activities. This paper first proposes a novel temporal violation transmission model inspired by an epidemic model to model the dynamics of time delay propagation. Afterward, a novel temporal violation prediction strategy is presented to estimate the number of temporal violations that may occur and determine the number of violations that must be handled to achieve the target service‐level agreement, namely, the on‐time completion rate. To the best of our knowledge, this is the first attempt to predict cloud workflow temporal violations at the workflow build‐time stage by analyzing the propagation of temporal violations. Experimental results demonstrate that our strategy can make highly accurate predictions and is scalable for a large batch of parallel workflows running in the cloud.

Alcohol consumption as a risk factor for tuberculosis: meta-analyses and burden of disease.

Meta-analyses of alcohol use, alcohol dosage and alcohol-related problems as risk factors for tuberculosis incidence were undertaken. The global alcohol-attributable tuberculosis burden of disease was also re-estimated.Systematic searches were conducted, reference lists were reviewed and expert consultations were held to identify studies. Cohort and case-control studies were included if there were no temporal violations of exposure and outcome. Risk relations (RRs) were pooled by using categorical and dose-response meta-analyses. The alcohol-attributable tuberculosis burden of disease was estimated by using alcohol-attributable fractions.36 of 1108 studies were included. RRs for alcohol use and alcohol-related problems were 1.35 (95% CI 1.09–1.68; I2: 83%) and 3.33 (95% CI 2.14–5.19; 87%), respectively. Concerning alcohol dosage, tuberculosis risk rose as ethanol intake increased, with evidence of a threshold effect. Alcohol consumption caused 22.02 incident cases (95% CI 19.70–40.77) and 2.35 deaths (95% CI 2.05–4.79) per 100 000 people from tuberculosis in 2014. Alcohol-attributable tuberculosis incidence increased between 2000 and 2014 in most high tuberculosis burden countries, whereas mortality decreased.Alcohol consumption was associated with an increased risk of tuberculosis in all meta-analyses. It was consequently a major contributor to the tuberculosis burden of disease.

A sprouting graph-based approach to analysing timed workflow processes with shared resources

Recently, temporal constraint satisfiability is regarded as an important criterion in the field of business process management. Existing methods do not fully investigate the various modes of shared resources, cannot provide the solutions for temporal violations or cannot develop the prototype system to automatically verify them. In this paper, we propose a new sprouting graph based approach to analysing temporal constraints of workflow processes with shared resources. First of all, in order to deal with various modes of shared resources we propose the corresponding patterns to record the executing information of resources. Then, how to automatically construct sprouting graph is presented, and the procedure of solving temporal violations is proposed. Finally, we also develop a prototype system. Compared with existing works, our approach is more effective and practical in the real business environment.

An efficient temporal verification algorithm for intersectant constraints in scientific workflow

It is usually essential to conduct temporal verification in order to ensure overall temporal correctness for the usefulness of execution results in a scientific workflow. For improving the efficiency of temporal verification, many efforts have been dedicated to the selection of more effective and efficient checkpoints along scientific workflow execution so that temporal violations can be found and handled in time. Most of checkpoint selection strategies involve temporal constraints, but the relations among the temporal constraints have been ignored. The only existing strategy considering relations among temporal constraints is for the nested situation and temporal dependency based only. However, the intersectant situation and non-dependency relationship of temporal constraints have to be considered. In this paper, a constraint adjustment strategy-based algorithm for efficient temporal verification in scientific workflow involved in both temporal dependency and temporal reverse-dependency is presented for the intersectant situation. Simulations show that the temporal verification efficiency of our algorithm is significantly improved.

An integrated framework of formal methods for interaction behaviors among industrial equipments

With the rapid advancement of Internet of Things, interaction behaviors among their industrial equipments have been complex dramatically whereas they have been becoming a kind of safety–critical systems and high requirements for safety have been urgent unprecedentedly. Therefore, it has been a great challenge for practicing engineers to ensure temporal correctness and reliability of interaction behaviors among industrial equipments. Nowadays, π-calculus, a process algebra and NuSMV, a symbolic model checker, have been widely applied to address this posed challenge respectively. However, they are always used separately. Because different formal methods focus on different aspects of systems, only one single method is still difficult to cope very well with the posed challenge. Therefore in this paper, an integrated framework of formal methods, which combines π-calculus with NuSMV, is constructed. π-Calculus can definitely specify equipment interaction, and NuSMV can automate verification process. Especially counterexamples fed back by NuSMV can help practicing engineers to trace temporal violations. Furthermore, a cooperative traffic lights control strategy is illuminated to show how the framework works.

Necessary and sufficient checkpoint selection for temporal verification of high-confidence cloud workflow systems

On-time completion is an important temporal QoS (Quality of Service) dimension and one of the fundamental requirements for high-confidence workflow systems. In recent years, a workflow temporal verification framework, which generally consists of temporal constraint setting, temporal checkpoint selection, temporal verification, and temporal violation handling, has been the major approach for the high temporal QoS assurance of workflow systems. Among them, effective temporal checkpoint selection, which aims to timely detect intermediate temporal violations along workflow execution plays a critical role. Therefore, temporal checkpoint selection has been a major topic and has attracted significant efforts. In this paper, we will present an overview of work-flow temporal checkpoint selection for temporal verification. Specifically, we will first introduce the throughput based and response-time based temporal consistency models for business and scientific cloud workflow systems, respectively. Then the corresponding benchmarking checkpoint selection strategies that satisfy the property of“necessity and sufficiency”are presented. We also provide experimental results to demonstrate the effectiveness of our checkpoint selection strategies, and finally points out some possible future issues in this research area.

Automated Pedestrian Safety Analysis at a Signalized Intersection in New York City: Automated Data Extraction for Safety Diagnosis and Behavioral Study

Automated computer vision techniques were used to analyze 2 h of video data collected at a major signalized intersection in New York City. The main objectives of this study were to diagnose pedestrian safety issues and identify contributing factors at the intersection and to demonstrate the feasibility of the automatic extraction of pedestrian data required for pedestrian behavior analysis—mainly pedestrian speed and gait parameters. The safety study was conducted with traffic conflict techniques. The main factor that contributed to the high number of pedestrian and vehicle conflicts was found to be pedestrian violations, mainly temporal violations in which pedestrians crossed the street during the “Don't Walk” or flashing “Don't Walk” phase. During the 2 h analyzed, about one-third of pedestrians were noncompliant with the signal timing or crosswalk boundary (17.9% spatial violations and 15.3% temporal violations). Pedestrian speed, step frequency, and step length were automatically extracted for 333 pedestrians and were found to follow the normal distribution with 95% confidence (mean and standard deviation of 1.47 ± 0.27 m/s, 1.96 ± 0.17 Hz, and 0.75 ± 0.14 m, respectively). Gait analysis showed that the walking speed for single pedestrians was 9% higher than for those who walked in groups. Males tended to be slightly faster than females, with higher step length but lower step frequency. Violators tended to have higher walking speeds compared with non-violators, and the difference in speed was dependent on step length but not on step frequency.

Early processing of auditory lexical predictions revealed by ERPs

Auditory lexical processing starts within 200ms after onset of the critical stimulus. Here, we used electroencephalography (EEG) to investigate whether (1) the so-called N200 effect can be triggered by single-item lexical context, and (2) such effects are robust against temporal violations of the signal. We presented items in which lexical status (i.e., is the stimulus a word or a pseudoword?) was determined at third syllable onset. The critical syllable could be naturally timed or delayed (by ∼440 or ∼800ms). Across all conditions, we observed an effect of lexicality that started ∼200ms after third syllable onset (i.e., an N200 effect in naturally timed items and a similar effect superimposed on the P2 for the delayed items). The results indicate that early lexical processes are robust against violations of temporal coherence.