Virtual Cycle Research Articles

SIMULATION OF VIRTUAL DISTRIBUTED PRODUCTION LOCATION UNDER CONDITIONS OF LIMITED POSSIBILITIES OF ENTERPRISE DEVELOPMENT

The task to research the enterprises when locating them in the new areas is posed and solved. The relevance of the problem is related to both moral and physical aging of production systems, which leads to the need for their modernization and reengineering. For the development of the enterprise, new areas are required to accommodate modern technological equipment. Due to the diversification of the company's activities and the appearance of new orders, it is advisable to place modern production lines with a high degree of automation in new areas. The requirements for the organization of new industries, taking into account the concept of Industry 4.0, have led to the creation of enterprises in the form of virtual industries focused on the creation of new innovative products. The aim of the work is to develop models for the rational location of virtual production in the new areas in conditions of limited enterprise capabilities. Due to the complexity of the problem being solved, the study is carried out in three stages: optimization of location on the earth's surface; creation of the communication infrastructure for virtual production; simulation of the virtual enterprise production cycle. The efficient location of virtual production is carried out using both local and multicriteria optimization. In order to create the communication infrastructure of the virtual enterprise the selection of the optimal route for highway laying is carried out. Simulation of the production cycle is carried out considering time delays and queues when performing technological operations. The new scientific result is the solution of the problem of virtual production system locating on the earth's surface, taking into account the proposed indicators and restrictions, which include the cost of land plots renting (acquiring), as well as the costs associated with earth and construction works. Mathematical methods were used: integer optimization, simulation modeling, agent-based modeling.
 Keywords: virtual enterprise, optimization of technological objects location, communication infrastructure of the enterprise, simulation modeling, agent-based modeling.

Dermatology Residency Applicants’ Concerns Due to COVID-19

Background: The COVID-19 pandemic caused substantial disruptions to medical education. We hypothesized that these disruptions may affect students applying to competitive residencies such as dermatology. Methods: A 24-question IRB-exempt, online, anonymous survey was distributed to 240 eligible medical students via social media to assess dermatology residency applicants’ concerns due to the COVID-19 pandemic and to collect student-proposed solutions to assist with the virtual application cycle. Eligibility consisted of US MD students applying to dermatology residency in the 2020-2021 or 2021-2022 application cycles. Statistical significance was calculated using the Chi-squared procedure, T-test/ANOVA, Mann Whitney test, and Kruskil Wallis tests with post-hoc Tukey and Mann Whitney tests. Results: Of 240 eligible students, 77 students attempted the survey whereas 69 students completed it (response rate 32%, completion rate 89%). Salient findings include students without home dermatology departments (WHD; n=24) who demonstrated concerns about research project changes (p=0.00). Students under-represented in medicine (UIM; n=34) concerned about lack of in-person interviews (p=0.00; p=0.04). MS3 (n=14), concerned about test cost (p=0.00), and effect on test scores because of COVID-19 (p=0.03). WHD and UIM applicants showed concerns about changes in clinical experiences (p=0.03, p= 0.03, respectively). Lastly, WHD, UIM and MS3 expressed concerns about obtaining quality recommendation letters (p=0.00, p=0.04, and p=0.03, respectively). Conclusion: Our findings demonstrate the various concerns shared by dermatology residency applicants because of the COVID-19 pandemic. The suggested solutions offered by participants in our study can be used to improve processes for candidates in the 2021-2022 residency application cycle.

Virtual cycles of stable (quasi-)maps with fields

We generalize the results of Chang–Li, Kim–Oh and Chang–Li on the moduli of p-fields to the setting of (quasi-)maps to complete intersections in arbitrary smooth Deligne–Mumford stacks with projective coarse moduli. In particular, we show that the virtual cycle of stable (quasi-)maps to a complete intersection can be recovered by the cosection localized virtual cycle of the moduli of p-fields of the ambient space.

The logarithmic gauged linear sigma model

We introduce the notion of log R-maps, and develop a proper moduli stack of stable log R-maps in the case of a hybrid gauged linear sigma model. Two virtual cycles (canonical and reduced) are constructed for these moduli stacks. The main results are two comparison theorems relating the reduced virtual cycle to the cosection localized virtual cycle, as well as the reduced virtual cycle to the canonical virtual cycle. This sets the foundation of a new technique for computing higher genus Gromov-Witten invariants of complete intersections.

Degeneracy loci, virtual cycles and nested Hilbert schemes, I

Given a map of vector bundles on a smooth variety, consider the deepest degeneracy locus where its rank is smallest. We show it carries a natural perfect obstruction theory whose virtual cycle can be calculated by the Thom-Porteous formula. We show nested Hilbert schemes of points on surfaces can be expressed as degeneracy loci. We show how to modify the resulting obstruction theories to recover the virtual cycles of Vafa-Witten and reduced local DT theories. The result computes some Vafa-Witten invariants in terms of Carlsson-Okounkov operators. This proves and extends a conjecture of Gholampour-Sheshmani-Yau and generalises a vanishing result of Carlsson-Okounkov.

Spectral analysis of short-wavelength emission by up-conversion in a Tm3+:ZBLAN dual-diode-pumped optical fiber

The fluorescence evolution along Tm3+-doped ZrF4–BaF2–LaF3–AlF3–NaF (ZBLAN) optical fibers, as well as amplified spontaneous emission in the UV-IR region with emphasis on 350 nm, 365 nm, and 450 nm, is studied, estimating optimal fiber lengths for amplification within the region. The fibers were diode-pumped with single and double lines (687 and/or 645 nm). Double-line pumping presents a quite superior efficiency for producing UV-blue signals with the benefit of requiring very short fibers, around 20 cm, compared to single-line pumping requiring more than 50 cm. A virtual cycle in which the pumps enhance each other’s absorption is the key to these systems.

Design of a Virtual Improvement Cycle for the analysis and diagnosis of stone facades using flipped classroom and problem-based learning

Design of a Virtual Improvement Cycle for the analysis and diagnosis of stone facades using flipped classroom and problem-based learning

Virtual Improvement Cycle adapted for construction teaching during the period of confinement

Virtual Improvement Cycle adapted for construction teaching during the period of confinement

The concept of heritage in the urban planning: Virtual Improvement Cycle of Teaching

The concept of heritage in the urban planning: Virtual Improvement Cycle of Teaching

An Efficient Void Routing in Geo-Graphics Routing Networks Depend on Virtual Co-Ordinates in WSN

For overcoming the obstacle of void routing on Geo-graphical routing, maximum controlling overheads and transmissions delayed have been used over wireless sensors network. Impress with the structures of composing edges node is don’t void routing, an adequate bypassings routings void protocols depends upon the virtual coordination is proposed. The simple ideas over the protocols is to sends a randomly structures of void edge over the regular once using mapping by edges node coordination into a virtual cycle. By using the virtual cycle, we can avoid the greedy forwardings from fail, such that there will not be routings void in forwardings protocols from sources to destinations and we can reduce the controlling overheads. Further, we can reduce the common lengths of routings path and minimize the transmissions delaying by using the virtual circle. Simulation highlights the higher delivery ratios; shorten the paths lengths, low controlling packets overheading and very less energies consumptions.

Damage evaluation under complex fatigue loading conditions

Fatigue damage and life assessment of multiaxial loadings is still an issue yet to resolve. Many methods have been proposed with promising agreements with the experimental results. However, the performance of such methods is, more than often, purely based on fatigue tests with simple loading conditions. In this work the stress scale factor (SSF) criterion and the virtual cycle counting (vcc) method are used to estimate fatigue life and damage accumulation with two damage accumulation rules. Fatigue tests were carried out with three different variable amplitude random loadings, applied to several specimens made from a 42CrMo4 high-strength steel. Fatigue crack plane measurements were compared with predictions from several critical plane models. The applied methods provided very acceptable results making the SSF package (SSF equivalent stress and virtual cycle counting method) a good method to estimate fatigue life and assessment of the damage accumulation in random fatigue loadings.

Experience in using public Cloud for Belle II experiment within HNSciCloud Project

The current level of flexibility reached by Cloud serviceproviders enables Physicists to take advantage of extra resources to extend the distributed computing infrastructure supporting High Energy Physics Experiments. However, the discussion about the optimal use of such kind of resources is currently ongoing. Moreover, because each Cloud provider offers its interfaces, API sets, and different service levels, the integration in the computing model of an experiment requires a specific work for each provider. In this paper, we summarize the experience matured in the usage of Cloud res urces offered by different providers within the Europeanproject Helix Nebula Science Cloud for Belle II experiment. The goal of the user-case was to run Montecarlo Production jobs properly on Virtual Machines created dynamically. To do that, we defined the golden image, based on CENTOS; we then set up the basic environment, the internal and external network, and local DNS services. For each cloud, we implemented a cache server based on Squid, while the orchestrator has been entralized on a single server located in the INFN-Napoli infrastructure. Finally, we integrated the available resources in the Belle II production framework based on DIRAC, using VCYCLE as Virtual Machine Life Cycle Manager. After a tuning activity that required the optimization of severalaspects included Image distribution and Network configuration, we wer able to run production jobs over the different Cloud with success.

An Integrated Success Factor Model of Professional Virtual Communities: Incorporation of the Operators, Members, and Life Cycle Perspectives

ABSTRACTDue to the growing importance of professional virtual communities (PVCs) to share professional knowledge in practice, this research proposes an integrated success factor model of PVCs encompassing (1) the componential aspect of a VC system from the operator’s perspective, (2) the knowledge-sharing aspect of a professional community from the members’ perspective, and (3) the VC’s life cycle perspective. An analytical framework was established from theories integrating dimensions from the perspective of operators and members and the virtual community life cycle. To collect and categorize the detailed items of success factors, a systematic literature review and a deductive content analysis were conducted with 64 selected articles. The content analysis results represented the specific perspective of PVCs distinguished from general virtual communities, highlighting factors such as reciprocity, content quality, self-efficacy, and recognition of contributions. Moreover, the inherent patterns in the model contingent to PVC life cycle stages were captured. First, different priorities in the relevant success factor dimensions were identified. Second, the patterns of changing values along with the life- cycle were recognized differently from the operators’ and member’s standpoints. This model can be utilized for the service providers of PVCs in terms of the business and design of PVCs as a strategic management tool and a design guideline.

Simulation-Based Virtual Cycle for Multi-Level Airport Analysis

The aeronautical industry is expanding after a period of economic turmoil. For this reason, a growing number of airports are facing capacity problems that can sometimes only be resolved by expanding infrastructure, with the inherent risks that such decisions create. In order to deal with uncertainty at different levels, it is necessary to have relevant tools during an expansion project or during the planning phases of new infrastructure. This article presents a methodology that combines simulation approaches with different description levels that complement each other when applied to the development of a new airport. The methodology is illustrated with an example that uses two models for an expansion project of an airport in The Netherlands. One model focuses on the operation of the airport from a high-level position, while the second focuses on other technical aspects of the operation that challenge the feasibility of the proposed configuration of the apron. The results show that by applying the methodology, analytical power is enhanced and the risk of making the wrong decisions is reduced. We identified the limitations that the future facility will have and the impact of the physical characteristics of the traffic that will operate in the airport. The methodology can be used for tackling different problems and studying particular performance indicators to help decision-makers take more informed decisions.

The fundamental class of smooth Kuranishi atlases with trivial isotropy

Kuranishi structures were introduced in the 1990s by Fukaya and Ono for the purpose of assigning a virtual cycle to moduli spaces of pseudoholomorphic curves that cannot be regularized by geometric methods. Their core idea was to build such a cycle by patching local finite dimensional reductions. The first sections of this paper discuss topological, algebraic and analytic challenges that arise in this program.We then develop a theory of Kuranishi atlases and cobordisms that transparently resolves these challenges, for simplicity concentrating on the case of trivial isotropy. In this case, we assign to a cobordism class of additive weak Kuranishi atlases both a virtual moduli cycle (VMC — a cobordism class of smooth manifolds) and a virtual fundamental class (VFC — a Cech homology class). We, moreover, show that such Kuranishi atlases exist on simple Gromov–Witten moduli spaces and develop the technical results in a manner that easily transfers to more general settings.

Virtual fundamental classes for moduli spaces of sheaves on Calabi–Yau four-folds

Let $({\bf X},\omega_{\bf X}^*)$ be a separated, $-2$-shifted symplectic derived $\mathbb C$-scheme, in the sense of Pantev, Toen, Vezzosi and Vaquie arXiv:1111.3209, of complex virtual dimension ${\rm vdim}_{\mathbb C}{\bf X}=n\in\mathbb Z$, and $X_{\rm an}$ the underlying complex analytic topological space. We prove that $X_{\rm an}$ can be given the structure of a derived smooth manifold ${\bf X}_{\rm dm}$, of real virtual dimension ${\rm vdim}_{\mathbb R}{\bf X}_{\rm dm}=n$. This ${\bf X}_{\rm dm}$ is not canonical, but is independent of choices up to bordisms fixing the underlying topological space $X_{\rm an}$. There is a 1-1 correspondence between orientations on $({\bf X},\omega_{\bf X}^*)$ and orientations on ${\bf X}_{\rm dm}$. Because compact, oriented derived manifolds have virtual classes, this means that proper, oriented $-2$-shifted symplectic derived $\mathbb C$-schemes have virtual classes, in either homology or bordism. This is surprising, as conventional algebro-geometric virtual cycle methods fail in this case. Our virtual classes have half the expected dimension, and from purely complex algebraic input, can yield a virtual class of odd real dimension. Now derived moduli schemes of coherent sheaves on a Calabi-Yau 4-fold are expected to be $-2$-shifted symplectic (this holds for stacks). We propose to use our virtual classes to define new Donaldson-Thomas style invariants 'counting' (semi)stable coherent sheaves on Calabi-Yau 4-folds $Y$ over $\mathbb C$, which should be unchanged under deformations of $Y$.

Smooth Kuranishi atlases with isotropy

Kuranishi structures were introduced in the 1990s by Fukaya and Ono for the purpose of assigning a virtual cycle to moduli spaces of pseudoholomorphic curves that cannot be regularized by geometric methods. Their core idea was to build such a cycle by patching local finite dimensional reductions, given by smooth sections that are equivariant under a finite isotropy group. Building on our notions of topological Kuranishi atlases and perturbation constructions in the case of trivial isotropy, we develop a theory of Kuranishi atlases and cobordisms that transparently resolves the challenges posed by nontrivial isotropy. We assign to a cobordism class of weak Kuranishi atlases both a virtual moduli cycle (VMC - a cobordism class of weighted branched manifolds) and a virtual fundamental class (VFC - a Cech homology class).

The topology of Kuranishi atlases

Kuranishi structures were introduced in the 1990s by Fukaya and Ono for the purpose of assigning a virtual cycle to moduli spaces of pseudoholomorphic curves that cannot be regularized by geometric methods. Starting from the same core idea (patching local finite-dimensional reductions), we develop a theory of topological Kuranishi atlases and cobordisms that transparently resolves algebraic and topological challenges in this virtual regularization approach. It applies to any Kuranishi-type setting, for example, atlases with isotropy, boundary and corners, or lack of differentiable structure.

Harnessing Women’s Potential as a Soft Engine for Growth – Lessons from Contrasting Trajectories between Finland and Japan for Growing Economies

Harnessing the vigor of women’s potential is essential for inclusive economic growth in a digital economy moving toward aging society. This can be a soft engine for sustainable growth substitutable for costly hard investment. While there exists explicit evidence of a virtual cycle between economic growth and gender balance improvement, emerging countries cannot afford to overcome the constraints of low income. Given the foregoing, this paper analyzed possible co-evolution between economic growth, gender balance improvement and digital innovation initiated by information and communication technology (ICT) advancement. Using a unique dataset representing the state of gender balance improvement in the function of economic growth and ICT advancement, an empirical numerical analysis of 44 countries was attempted. These countries were classified as emerging, industrialized and with a specific culture. It was found that while industrialized countries, typically Finland, have realized high performance in co-evolution, emerging countries have been constrained by low ICT advancement, and countries with a specific culture have, notwithstanding their high economic level, also been constrained by a traditional male-dominated culture. Japan is a typical case. Based on these findings, lessons from contrasting trajectories between Finland and Japan for emerging countries were analyzed. It is suggested that advancement of ICT, not only quantitatively but also qualitatively in such a way as constructing a self-propagating system, is crucial for emerging countries. A new practical approach for harnessing the potential resources for sustainable growth was thus explored.

Traffic demand estimation for lane groups at signal‐controlled intersections using travel times from video‐imaging detectors

The purpose of this study is to present a new method for lane-based traffic demand estimation using travel times from video-imaging detectors. The method overcomes the following two shortcomings of loop-detector-based algorithms: the fact that the actual demand is unknown when detectors are located upstream from the stop lines within a short distance; and the difficulty in calculating the ratio between streams in different lane groups if detectors are located at the upper reaches of the links. First, the authors analyse a variety of travel time patterns and introduce the concept of a virtual cycle that satisfies the criteria that all vehicles entering into a link in one virtual cycle have just departed from a downstream stop line within a single signal cycle. Next, the authors improve the travel time reduction rate model for queued vehicles in each cycle, and enhance the algorithms to estimate the lane-based traffic demand under different conditions. Finally, all parameters are calibrated and the new models are evaluated. The results show that: the maximum, minimum and average deviations over 12 cycles are 38.50, 0.02 and 16.19%, respectively. The findings in this study have potential applicability for use in traffic control systems, especially where oversaturated conditions are present.