A projective formalism applied to topological and probabilistic event structures

We define a new denotational semantics for a first-order probabilistic programming language in terms of probabilistic event structures. This semantics is intensional, meaning that the interpretation of a program contains information about its behaviour throughout execution, rather than a simple distribution on return values. In particular, occurrences of sampling and conditioning are recorded as explicit events, partially ordered according to the data dependencies between the corresponding statements in the program. This interpretation is adequate: we show that the usual measure-theoretic semantics of a program can be recovered from its event structure representation. Moreover it can be leveraged for MCMC inference: we prove correct a version of single-site Metropolis-Hastings with incremental recomputation, in which the proposal kernel takes into account the semantic information in order to avoid performing some of the redundant sampling.

Overlay networks have emerged as a powerful and flexible platform for developing new disruptive network applications. The performance and reliability of overlay applications depend on the capability of overlay networks to dynamically adapt to various factors such as link/node failures, overlay link quality, and overlay node characteristics. In order to achieve this, the overlay applications require scalable and open overlay monitoring services to monitor, aggregate globally distributed events and take appropriate control actions. In this paper, we propose the techniques and algorithms to create an optimal event monitoring and aggregation infrastructure (called MOON) that minimizes the monitoring latency (i.e., event retrival/detection time) and event aggregation cost (i.e., intrusiveness) considering the large-scale geographical and network distribution of overlay nodes. The proposed monitoring infrastructure, MOON, clusters and organizes overlay nodes efficiently such that overlay applications can globally monitor and query correlated events in an overlay network with minimum latency and monitoring cost. Our simulations and experimental studies show the evaluation of MOON under many various topological structures, network sizes, and event aggregation volumes.

Rule-based and object-based event structures for membrane systems

By using the coupled model of Hindmarsh—Rose neuronal systems, we numerically investigate the effect of topology structures on the firing patterns transition (FPT). A four-cell coupled system with all possible configurations are studied. We select the membrane current Iext as a controllable parameter, and set it to be near the left side for one of the bifurcation points. It is found that to have a response from some external stimuli with the proper amplitude and frequencies, the transition will appear between different firing states only when the cells in the system are coupled with some proper topological structures, which implies the occurrence of FPT induced by the configuration in the coupled system. Similar FPT phenomena could also be observed in a five-cell coupled system. Furthermore, we find that such transition behaviors may have some inherent relevance with the synchronization error and the average connective number among cells in the coupled system for different topology structures. These results suggest that the biological neuron systems may achieve an effective response to the external feeble stimulus by selecting the proper configuration and using the corresponding transition mode.

A logical characterization of well branching event structures

This paper presents the methodology and analysis procedure required for a nonlinear dynamic soil-pile-structure interaction analysis of the offshore structures subjected to ductility level earthquakes with emphasis on the design of a well-balanced optimized structural system. The analysis uses a 3- dimensional MicroSAS II structural model with full structural representation of the piles to which a series of nonlinear soil springs and dashpots are attached. The nonlinear inelastic soil elements, cyclic strain rate, gapping and hysteretic energy dissipation were properly considered. The nonlinear inelastic behaviors of the structural members were modeled. A new technique has been applied to identify the time-varying power spectral density of the earthquake accelerograms. The advanced nonlinear inelastic finite element analysis was performed to evaluate the structural stability of the legskirtpile connections. Introduction The current design criteria specified in the API RP 2A-WSD address the strength level earthauke design and ductility level earthquake design. The typical design approach considering the strength level earthquake is based on the natural periods of the linearlized structural model, the modal analysis, and response spectra specified in the codes. In the seismically active areas, platform response to the rare, intense earthquake motions or ductility level earthquake may involve inelastic behavior and structural damage may occur but structure collapse shall be avoided. It may be unrealistic to use a linear structural model and response spectrum methods to design an offshore structure subjected to the very intense ductility level earthquake without huge cost penalty. For these reasons, the time history method is recommended in API RP 2A to perform the nonlinear, inelastic, dynamic soil-pile-structure interaction analysis to demonstrate the sufficient structural system redundancy such that the load redistribution and inelastic deformation will occur to prevent offshore structural collapse or the abrupt changes in stiffness in the vertical configuration of the offshore structure. Some examples had been investigated for the dynamic overload analysis of the offshore structure [1, 2, and 3]. In this paper, a four-leg and eight-skirt-pile platform (shown in Figure 1) designed for north offshore Trinidad in 497 ft water was used in the analysis. As per the seismic hazard study, three sets of seafloor time history accelerograms (two for shallow crustal earthquake with Mw 7.3 and Mw 7.4, and one for interplate subduction-zone earthquake with Mw 7.7), which were representative of 2,000-year return period earthquake at the site, were considered. It was demonstrated that the structure-optimized platform can withstand the 2000- year earthquake at the north offshore Trinidad without structural system collapse. It is estimated that over 15% of the structural steel have been saved after the reconfiguration of the structural system. Figure 1 Outline of the platform topsides and jacket model (Available in full paper) Ground motion accelerograms Three sets of accelerograms (3 components/set) were selected as being representative of the ductility level earthquake seafloor motions for the structural seismic design and analysis. The accelerograms are listed as follows:Yermo accelerogram recorded during the 1992 Landers, California earthquake of magnitude Mw of 7.3

Event Structures for Local Traces

In the design of structures, incorporating resilient structural systems is important to protect the structures in extreme or abnormal load events. In many cases, these systems are necessary to ensure continued operation of an essential facility, although it is also important in protecting the investment associated with a major development, or the preservation of historic buildings. Various systems have been developed to accommodate abnormal loads caused by seismic ground motions that are designed to create a high level of resiliency. The intent of this paper is to consider resiliency for a range of building types and the benefits of enhanced seismic structural systems when subjected to extreme loads. Because the Ninth District U.S. Court of Appeals, San Francisco, constructed in 1905, is so important historically, the building was seismically retrofitted to include friction pendulum bearings under existing columns, located just above the foundation level. At 365 Main Street, San Francisco, an existing 1940s non-ductile reinforced concrete warehouse was converted into a stateof-the-art internet co-location facility by introducing seismic isolation as well as an entirely self-sufficient fully redundant building services systems allowing for continued operation after an extreme seismic event. The Cathedral of Christ the Light in Oakland, California, combines seismic isolation with a reinforced concrete structure to achieve a building with a desired life of hundreds of years, even though the site is only a few kilometers from the Hayward Fault. The 222 South Main Office Building, Salt Lake City and the San Diego Central Courthouse use a diagonal system of unbonded braces and viscous dampers respectively to address building resiliency.

Power flow controllers and DC circuit breakers are compulsory components in a multi‐terminal DC grid with overhead lines. They are both composed of similar power electronic devices and thus can be reasonably combined together to realize cost savings. This paper proposes a multi‐port circuit breaker integrated with a multi‐port power flow controller (M‐PFCHCB). The topology structure, operation principles, control strategy and parameter configuration are illustrated in detail. The main breakers are composed of unidirectional power electronic switches, and the selection branch is based on two diode strings, which can significantly save the investment of the breaker. The proposed M‐PFCHCB is able to deal with the fault isolation and the ultra‐fast disconnector failure with high performance. Besides, the power flow of multiple lines can be simultaneously regulated by the M‐PFCHCB without any external power supply. The internal power balance is achieved by controlling the AC circulating current inside the M‐PFCHCB. The simulations conducted on PSCAD in a five‐terminal DC grid with eight DC lines verify the feasibility of the proposed M‐PFCHCB. The technical and economic analysis performed proves that the proposed M‐PFCHCB can achieve the comprehensive functions of fault isolation and power flow control with low construction cost.

Flexible DC transmission (VSC-HVDC) after a large number of access to the power system, the flexible control and unique topological structure will greatly change the system fault response characteristics. This paper aims at studying the effect of VSC-MTDC system of different topological structures and different control modes on power system transient stability. In this paper, firstly, a four terminal flexible HVDC transmission system is constructed. The statistical analysis of clearing time critical with different topologies in three phase short circuit fault is carried out. Through statistical analysis, the relationship between VSC-MTDC topology and transient stability is obtained. Based on that, studying the influence of control mode on transient stability, in turn, four converters are set to the constant DC voltage control, analysis of the impact of control on the stability of the power grid integrated proximal and distal line fault. Finally combined with extended equal area criterion (EEAC) analyze qualitatively the influence of VSC-MTDC accessing on the transient stability of power system.

Topological phases play a novel and fundamental role in matter and display extraordinary robustness to smooth changes in material parameters or disorder. A crossover between topological material and quantum information may lead to inherent fault-tolerant quantum simulations and quantum computing. Quantum features may be preserved by being encoded among topological structures of physical evolution systems. This requires stimulation, manipulation, and observation of topological phenomena at the single quantum particle level, which has not, however, yet been realized. It is asked whether the quantum features of single photons can be preserved in topological structures. The boundary states are experimentally observed at the genuine single-photon level and the performance of the topological phase is demonstrated to protect the quantum features against diffusion-induced decoherence in coupled waveguides and noise decoherence from the ambient environment. Compatibility between macroscopic topological states and microscopic single photons in the ambient environment is thus confirmed, leading to a new avenue to "quantum topological photonics" and providing more new possibilities for quantum materials and quantum technologies.

The article suggests a technique for parameters determining of a maintenance and repair system (MRS) for a geographically dispersed park of technical systems (PTS). The solutions of problems of this class assume the formation, as a rule, of the topological and functional structures of the system. In addition, for geographically dispersed fleet of vehicles, it is necessary to solve the problem of distributing equipment that requires maintenance to service areas. The solution of the problem in such a formulation requires the consideration of a large number of heterogeneous factors (variables in the formalized representation of the problem). And this leads to a large dimension of the problem, which makes it difficult to obtain acceptable solutions by known methods. To overcome these difficulties, the article proposes a technique for solving such problems based on its decomposition into three problems (tasks of three levels) - the task of forming requests for maintenance, the task of forming the topological structure of the system and the task of forming the functional structure of MRS. To solve each of the problems, its formulation and methods of solution are proposed. At the first level, it is advisable to simulate the processes of changing the technical state of the PTS samples and forming applications for its servicing. Applications must be formed in such a way as to optimize the reliability (availability) of technical systems and (or) the costs of their operation. At the second level, taking into account the existing applications, it is necessary to model the functioning of the MRS elements, optimize the PTS readiness indicators and operational costs by selecting the MRS topology and the operational strategies of its elements, and by optimally distributing the maintenance and repair tasks according to the levels and elements of the system. At the third level, it is necessary to calculate and minimize the capital costs for the construction of the MRS and operating costs for various options for its construction, various ways of distributing the maintenance tasks and repairing the PTS by levels and elements of the system to make decisions about the meaning of the maintenance and repair parameters. The proposed methodology makes it possible to obtain acceptable solutions for large-dimensional problems and heterogeneous factors (task solution variables).

This paper uses fractal theory to analyze interorganizational information systems (IOS). Firstly, IOS’s structure has fractal characteristics of self-similarity, self-optimization and self-organization, consequently, gives the concept and definition of fractal interorganizational information systems (FIOS). Thirdly, builds IOS topological structure fits actual needs based on Diffused-Limited Aggregation (DLA) model to optimize the growth rule of IOS, then, designs six topological structures of FIOS and estimates approximatively their fractal dimension values. Finally, gives fractal interorganizational information systems application to optimize the supply chain network structure to improve operation efficiency.

<p>Due to its huge material and energy consumption, super tall buildings exert great impact on the environment. Embodied carbon is an important tool to measure the environmental impacts of super tall buildings. The embodied carbon of super tall buildings could be optimized by integrating the energy dissipation devices in the structural system. Viscoelastic coupling dampers (VCDs) is a kind of efficient energy dissipation devices. By replacing coupling beams in structural configurations, VCDs can effectively increase the level of inherent damping of structure, and thus reduce the internal forces of structural members subject to lateral loads. Optimization for the sectional dimension of structural components is made possible, accompanied by reduction in embodied carbon. A super tall building located in high seismicity area is presented as an example to illustrate embodied carbon based integrated structural design method. The results for a real super tall building project show that the proposed method is reasonable and can effectively reduce embodied carbon and total cost of super tall buildings.</p>

Design, fabrication and vibration characteristics of a novel composite auxetic structure embedded with resonators