Concurrent Transitions Research Articles

The influence of educational transitions on loneliness and mental health from emerging adults’ perspectives

ABSTRACT Educational transitions can influence loneliness and increase mental health issues for young people transitioning between educational stages. The aim was to explore the link between educational transitions and emerging adults’ loneliness and mental health and how they perceive they can alleviate and/or improve these issues. Semi-structured qualitative interviews with a total of 12 emerging adults, 10 females and two males aged 18–29 (mean age, 22.91) were conducted. Data were analysed using qualitative content analysis. Emerging adults’ loneliness and mental health across educational transitions could be influenced by changes to their sense of security, for example concurrent transitions, increased academic demands, changed social network, insufficient attachment, lack of community, or changed physical environment. Transitions can be associated with positive expectations and self-development but also worry, emotional turmoil, loneliness, and mental health issues. A better transition experience can be enabled by increasing resources and activities and promoting a secure environment.

Longitudinal Changes in a Claims-Based Frailty Proxy Measure Compared to Concurrent Changes in the Fried Frailty Phenotype.

Frailty is a dynamic aging-related syndrome, but measuring frailty transitions is challenging. The Faurot frailty index is a validated Medicare claims-based frailty proxy based on demographic and billing information. We evaluated whether 3-year changes in the Faurot frailty index were consistent with concurrent changes in the frailty phenotype in a cohort of older adults. We used longitudinal data from the National Health and Aging Trends Study (NHATS) with Medicare claims linkage (2010-2018). We identified older adults (66+ years) in the 2011 and 2015 NHATS cohorts with at least 1 year of Medicare fee-for-service continuous enrollment (N = 6 951). We described annual changes in mean claims-based frailty for up to 3 years, based on concurrent transitions in the frailty phenotype. At baseline, 32% were robust, 48% prefrail, and 19% frail based on the frailty phenotype. Mean claims-based frailty for older adults who were robust at baseline and worsened to frail increased over 3 years (0.09-0.25). Similarly, those who worsened from prefrail to frail experienced an increase in mean claims-based frailty (0.14-0.26). Improvements in the frailty phenotype did not correspond to decreases in claims-based frailty. Older adults whose frailty phenotype improved over time had a lower baseline claims-based frailty score than those who experienced stable or worsening frailty. Older adults who experienced a frailty phenotype worsening over 3 years experienced concurrent increases in the Faurot frailty index. Our results suggest that claims data may be used to identify clinically meaningful worsening in frailty.

Symbolic Specialization of Rewriting Logic Theories withPresto

AbstractThis paper introduces$\tt{{Presto}}$, a symbolic partial evaluator for Maude’s rewriting logic theories that can improve system analysis and verification. In$\tt{{Presto}}$, the automated optimization of a conditional rewrite theory$\mathcal{R}$(whose rules define the concurrent transitions of a system) is achieved by partially evaluating, with respect to the rules of$\mathcal{R}$, an underlying, companion equational logic theory$\mathcal{E}$that specifies the algebraic structure of the system states of$\mathcal{R}$. This can be particularly useful for specializing an overly general equational theory$\mathcal{E}$whose operators may obey complex combinations of associativity, commutativity, and/or identity axioms, when being plugged into a host rewrite theory$\mathcal{R}$as happens, for instance, in protocol analysis, where sophisticated equational theories for cryptography are used.$\tt{{Presto}}$implements different unfolding operators that are based onfolding variant narrowing(the symbolic engine of Maude’s equational theories). When combined with an appropriate abstraction algorithm, they allow the specialization to be adapted to the theory termination behavior and bring significant improvement while ensuring strong correctness and termination of the specialization. We demonstrate the effectiveness of$\tt{{Presto}}$in several examples of protocol analysis where it achieves a significant speed-up. Actually, the transformation provided by$\tt{{Presto}}$may cut down an infinite folding variant narrowing space to a finite one, and moreover, some of the costly algebraic axioms and rule conditions may be eliminated as well. As far as we know, this is the first partial evaluator for Maude that respects the semantics of functional, logic, concurrent, and object-oriented computations.

C60 at high resolution

Chemical Physics It generally takes more energy for molecules to vibrate than to rotate. A vibrational absorption band thus encompasses many distinct concurrent rotational transitions, but these tend to blur together when the molecules have more than a few atoms. Changala et al. succeeded in cooling C60 fullerenes sufficiently to obtain rotational resolution within a C–C stretching band. Success hinged on careful optimization of argon buffer gas flow. Such quantum state–resolved features could aid characterization of fullerene-type compounds in exotic environments such as interstellar space. Science , this issue p. [49][1] [1]: /lookup/doi/10.1126/science.aav2616

Concurrent transitions in wear rate and surface microstructure in nanocrystalline Ni-W

Nanocrystalline metals are promising materials for wear-resistant applications due to their superior strength and hardness, but prior work has shown that cyclic loading can lead to coarsening. In this study, scratch wear tests were carried out on nanocrystalline Ni-19 at.% W films with an as-deposited grain size of 3 nm, with systematic characterization performed after different wear cycles. A new gradient nanograined microstructure is observed and a direct connection between wear rate and subsurface microstructure is discovered. A second Ni-W specimen with the same composition and a 45 nm average grain size is produced by annealing the original specimen. Subsequent wear testing shows that an identical subsurface microstructure is produced in this sample, emphasizing the importance of the cross-over in deformation mechanisms for determining the steady-state grain size during wear.

Slime Mould Games Based on Rough Set Theory

Abstract We define games on the medium of plasmodia of slime mould, unicellular organisms that look like giant amoebae. The plasmodia try to occupy all the food pieces they can detect. Thus, two different plasmodia can compete with each other. In particular, we consider game-theoretically how plasmodia of Physarum polycephalum and Badhamia utricularis fight for food. Placing food pieces at different locations determines the behavior of plasmodia. In this way, we can program the plasmodia of Physarum polycephalum and Badhamia utricularis by placing food, and we can examine their motion as a Physarum machine-an abstract machine where states are represented as food pieces and transitions among states are represented as movements of plasmodia from one piece to another. Hence, this machine is treated as a natural transition system. The behavior of the Physarum machine in the form of a transition system can be interpreted in terms of rough set theory that enables modeling some ambiguities in motions of plasmodia. The problem is that there is always an ambiguity which direction of plasmodium propagation is currently chosen: one or several concurrent ones, i.e., whether we deal with a sequential, concurrent or massively parallel motion. We propose to manage this ambiguity using rough set theory. Firstly, we define the region of plasmodium interest as a rough set; secondly, we consider concurrent transitions determined by these regions as a context-based game; thirdly, we define strategies in this game as a rough set; fourthly, we show how these results can be interpreted as a Go game.

Unfolding of Parametric Boolean Networks

In systems biology, models of cellular regulatory processes such as gene regulatory networks or signalling pathways are crucial to understanding the behaviour of living cells. Available biological data are however often insufficient for full model specification. In this paper, we focus on partially specified models where the missing information is abstracted in the form of parameters. We introduce a novel approach to analysis of parametric logical regulatory networks addressing both sources of combinatoric explosion native to the model. First, we introduce a new compact representation of admissible parameters using Boolean lattices. Then, we define the unfolding of parametric Boolean networks. The resulting structure provides a partial-order reduction of concurrent transitions, and factorises the common transitions among the concrete models. A comparison is performed against state-of-the-art approaches to parametric model analysis.

Toward uniform random generation in 1-safe Petri nets

We study the notion of uniform measure on the space of infinite executions of a 1-safe Petri net. Here, executions of 1-safe Petri nets are understood up to commutation of concurrent transitions, which introduces a challenge compared to usual transition systems. We obtain that the random generation of infinite executions reduces to the simulation of a finite state Markov chain. Algorithmic issues are discussed.

Proof-relevant π-calculus: a constructive account of concurrency and causality

We present a formalisation in Agda of the theory of concurrent transitions, residuation and causal equivalence of traces for the π-calculus. Our formalisation employs de Bruijn indices and dependently typed syntax, and aligns the ‘proved transitions’ proposed by Boudol and Castellani in the context of CCS with the proof terms naturally present in Agda's representation of the labelled transition relation. Our main contributions are proofs of the ‘diamond lemma’ for the residuals of concurrent transitions and a formal definition of equivalence of traces up to permutation of transitions.In the π-calculus, transitions represent propagating binders whenever their actions involve bound names. To accommodate these cases, we require a more general diamond lemma where the target states of equivalent traces are no longer identical, but are related by abraidingthat rewires the bound and free names to reflect the particular interleaving of events involving binders. Our approach may be useful for modelling concurrency in other languages where transitions carry meta-data sensitive to particular interleavings, such as dynamically allocated memory addresses.

Life transitions of adolescents and young adults with life-limiting conditions.

A systematic review was conducted to appraise and classify evidence related to the life transitions of adolescents and young adults with life-limiting conditions. The databases searched were MEDLINE, CINAHL, PsycINFO, CancerLit, and AMED. Methodological quality was assessed using an established tool and the final articles included in the study were rated as moderate to high quality. Articles were then assessed based on the insight that they provided into life transitions for adolescents and young adults. Eighteen studies were included in the final review, with two major life transitions identified as pertinent: 'illness transition' and 'developmental transition'. These concurrent transitions were found to be relevant to adolescents and young adults with life-limiting conditions, generating complex needs. Sub-themes within the transitions were also identified. Furthermore, the illness transition was found to also impact significant others, namely family members, having physical, mental and emotional health implications and requiring them to make adaptations. Future research is needed to focus on adolescent and young adult perspectives to bring further insight into these key transitions, since such perspectives are currently underrepresented. Attention to the impact of the illness on the whole family would be useful to expand findings from this review.

“Truly concurrent” and nondeterministic semantics of discrete-time Petri nets

In the paper, a "truly concurrent" and nondeterministic semantics is defined in terms of branching processes of discrete-time Petri nets (DTPNs). These nets may involve infinite numbers of transitions and places, infinite number of tokens in places, and (maximal) steps of concurrent transitions, which allows us to consider this class of DTPNs to be the most powerful class of Petri nets. It is proved that the unfolding (maximal branching process) of the DTPN is the greatest element of a complete lattice constructed on branching processes of DTPNs with step semantics. Moreover, it is shown that this result is true also in the case of maximal transition steps if additional restrictions are imposed on the structure and behavior of the DTPN.

Observation of long-range tertiary interactions during ligand binding by the TPP riboswitch aptamer.

The thiamine pyrophosphate (TPP) riboswitch is a cis-regulatory element in mRNA that modifies gene expression in response to TPP concentration. Its specificity is dependent upon conformational changes that take place within its aptamer domain. Here, the role of tertiary interactions in ligand binding was studied at the single-molecule level by combined force spectroscopy and Förster resonance energy transfer (smFRET), using an optical trap equipped for simultaneous smFRET. The 'Force-FRET' approach directly probes secondary and tertiary structural changes during folding, including events associated with binding. Concurrent transitions observed in smFRET signals and RNA extension revealed differences in helix-arm orientation between two previously-identified ligand-binding states that had been undetectable by spectroscopy alone. Our results show that the weaker binding state is able to bind to TPP, but is unable to form a tertiary docking interaction that completes the binding process. Long-range tertiary interactions stabilize global riboswitch structure and confer increased ligand specificity.

Confusion diagnosis and avoidance of discrete event systems using supervisory control

Nondeterministic firing of concurrent transitions in Petri nets (PNs) may lead to the disappearance of conflicts. The disappearance implies that the partial conflicting transitions in a conflict become disabled before the resolution of the conflict. The phenomenon is called confusions that are caused by the interlacement of conflicting and concurrent transitions in PNs, which generates incomplete and faulty system conflicting behavior such that conflicts cannot be correctly resolved. In this paper, conflict‐increasing confusions (CICs) and conflict‐decreasing confusions (CDCs) in a PN are investigated. The relation graph of conflicts and confusions (RGC2) in a PN is proposed to detect the structure of confusions. To avoid the occurrence of confusions in a PN, an algorithm based on generalized mutual exclusion constraints (GMECs) is proposed, which can generate confusion‐avoidance supervisors such that the occurrence of conflicts can be ensured in a PN. Finally, an example of confusion detection and avoidance in a flexible assembly system is presented. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Proof-relevant pi-calculus

Formalising the pi-calculus is an illuminating test of the expressiveness of logical frameworks and mechanised metatheory systems, because of the presence of name binding, labelled transitions with name extrusion, bisimulation, and structural congruence. Formalisations have been undertaken in a variety of systems, primarily focusing on well-studied (and challenging) properties such as the theory of process bisimulation. We present a formalisation in Agda that instead explores the theory of concurrent transitions, residuation, and causal equivalence of traces, which has not previously been formalised for the pi-calculus. Our formalisation employs de Bruijn indices and dependently-typed syntax, and aligns the "proved transitions" proposed by Boudol and Castellani in the context of CCS with the proof terms naturally present in Agda's representation of the labelled transition relation. Our main contributions are proofs of the "diamond lemma" for residuation of concurrent transitions and a formal definition of equivalence of traces up to permutation of transitions.

Confusion Control in Generalized Petri Nets Using Synchronized Events

The loss of conflicting information in a Petri net (PN), usually called confusions, leads to incomplete and faulty system behavior. Confusions, as an unfortunate phenomenon in discrete event systems modeled with Petri nets, are caused by the frequent interlacement of conflicting and concurrent transitions. In this paper, confusions are defined and investigated in bounded generalized PNs. A reasonable control strategy for conflicts and confusions in a PN is formulated by proposing elementary conflict resolution sequences (ECRSs) and a class of local synchronized Petri nets (LSPNs). Two control algorithms are reported to control the appeared confusions by generating a series of external events. Finally, an example of confusion analysis and control in an automated manufacturing system is presented.

Confusion avoidance for discrete event systems by P/E constraints and supervisory control

Non-deterministic firing of concurrent transitions in Petri nets (PNs) may lead to the information loss of conflicts. The phenomenon is called confusions that usually occur in the evolution of a PN containing interlaced conflicting and concurrent transitions, which generates incomplete and faulty system conflicting behaviour such that conflicts cannot be correctly resolved. This paper investigates detection and avoidance approaches of confusions in safe PNs. First, the structural features of confusions are characterized and two detection algorithms are proposed to capture confusion subnets in a PN according to their structural features. Secondly, a method of supervisory control is developed to avoid the occurrence of confusions in a PN. It contains a policy of the generation of confusion avoidance constraints and a method to synthesize supervisors enforcing a class of place and enabling degree constraints, P/E constraints for short. Finally, an example of confusion detection and avoidance in an automated manufacturing system is presented.

A conformance relation for model-based testing of PLC

This paper focuses on the execution of conformance testing of PLC with I/O scanning which executes a control code; it is assumed that the test sequence has been built from a finite state machine that represents the specified behavior. It is first shown that the conformance relation which allows to decide whether the implementation conforms to the specification or not must be defined from a sequence of observations, and not from only one observation, to take into account the delays introduced by the I/O scanning. Then, a second conformance relation is proposed to avoid that asynchronous detection of synchronous input changes leads to biased or non-valid verdicts; this new relation is defined from the analysis of concurrent transitions and accepted sequences in the specification model.

Confusion Analysis and Detection for Workflow Nets

Option processes often occur in a business procedure with respect to resource competition. In a business procedure modeled with a workflow net (WF-net), all decision behavior and option operations for business tasks are modeled and performed by the conflicts in corresponding WF-net. Concurrency in WF-nets is applied to keep a high-performance operation of business procedures. However, the firing of concurrent transitions in a WF-net may lead to the disappearance of conflicts in the WF-net. The phenomenon is usually called confusions that produces difficulties for the resolution of conflicts. This paper investigates confusion detection problems in WF-nets. First, confusions are formalized as a class of marked subnets with special conflicting and concurrent features. Second, a detection approach based on the characteristics of confusion subnets and the integer linear programming (ILP) is developed, which is not required to compute the reachability graph of a WF-net. Examples of the confusion detection in WF-nets are presented. Finally, the impact of confusions on the properties of WF-nets is specified.

Coarsening behaviour of gamma prime precipitates and concurrent transitions in the interface width in Ni-14 at.% Al-7 at.% Cr

Coupling atom probe tomography and transmission electron microscopy, the temporal evolution of γ′ precipitate morphology and size distribution and compositional width of the γ/γ′ interface, have been tracked in a model Ni-14Al-7Cr (at.%) alloy, during isothermal annealing at 800 °C subsequent to rapid quenching. During the initial annealing period, coalescence-dominated growth and coarsening of γ′ precipitates are accompanied by a gradual decrease in the interface width, eventually leading to classical LSW coarsening with a constant interface width at extended annealing time periods.

Confusion Diagnosis and Control of Discrete Event Systems Using Synchronized Petri Nets

AbstractThe mixture of conflicting transitions and concurrent transitions in Petri nets can lead to the loss of conflict information, which is an unfortunate phenomenon in discrete event systems, usually called confusions. They appear in the processes of resource allocation and may cause incomplete decision‐making on conflicts. Hence, a confusion detection method and a control strategy are required. This paper proposes a class of confusion control event reconfigurable (CCR) nets to control confusions with the evolution of markings. Their properties such as safety and liveness with the mapping from original Petri nets to CCR nets are investigated. Two confusion control algorithms are proposed to generate a set of control code sequences, which can completely control the occurrences of confusions. Then, a confusion detection algorithm with polynomial time complexity is developed. Finally, an example of confusion analysis in automated manufacturing systems is presented.