Symbolic Implementation of Connectors in BIP

BIP is a component framework for constructing systems by superposing three layers of modeling: Behavior, Interaction, and Priority. Behavior is represented by labeled transition systems communicating through ports. Interactions are sets of ports. A synchronization between components is possible through the interactions specified by a set of connectors. When several interactions are possible, priorities allow to restrict the non-determinism by choosing an interaction, which is maximal according to some given strict partial order. The BIP component framework has been implemented in a language and a tool-set. The execution of a BIP program is driven by a dedicated engine, which has access to the set of connectors and priority model of the program. A key performance issue is the computation of the set of possible interactions of the BIP program from a given state. Currently, the choice of the interaction to be executed involves a costly exploration of enumerative representations for connectors. This leads to a considerable overhead in execution times. In this paper, we propose a symbolic implementation of the execution model of BIP, which drastically reduces this overhead. The symbolic implementation is based on computing boolean representation for components, connectors, and priorities with an existing BDD package

Experimental Study on Behavior of Shear Connectors Embedded in Steel-Reinforced Concrete Joints

[EN] This paper presents an experimental study on the behavior of shear connectors embedded in steel-reinforced concrete joints. In steel-reinforced concrete joints, the shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface. Further, in Japan, some studies in recently have also been undertaken to apply perfobond rib shear connector (PBL), which is a type of shear connectors developed in civil engineering, to the steel-reinforced concrete joints in building structures. To clarify the influence of the arrangement methods of headed studs and PBLs to reinforced concrete member on the joints, T-shaped subassembrages were tested under the monotonic tensil loading.This experiment is constituted of the following; Exp. I: Bond strength across the steel-concrete interface. Exp. II: Arrangement methods of these shear connectors to reinforced concrete member. The following can be drawn from the test results 1) The experimental values of the average maximum and residual bond strength are 0.230-0.280 and 0.15-0.18 N/mm2, respectively. 2) When the distance of between the upper surface of the reinforced concrete member from the first layer for headed studs are small, the failure mode of the specimens is similar to a concrete-cone type failure. 3) In case that the total number of headed studs or the hole provided to PBL is the same, the maximum load of the specimen with the parallel arrangement is larger than that of when shear connecters are vertically arranged. 4) The shear strength of headed studs in the joints embedded the steel member in the reinforced concrete member is estimated by superposing the average residual bond strength across the steel-concrete interface.Nakamori, R.; Kageyama, Y.; Baba, N. (2018). Experimental Study on Behavior of Shear Connectors Embedded in Steel-Reinforced Concrete Joints. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 527-532. https://doi.org/10.4995/ASCCS2018.2018.7124OCS52753

Extended Connectors: Structuring Glue Operators in BIP

Based on a variation of the BIP operational semantics using the offer predicate introduced in our previous work, we extend the algebras used to model glue operators in BIP to encompass priorities. This extension uses the Algebra of Causal Interaction Trees, T(P), as a pivot: existing transformations automatically provide the extensions for the Algebra of Connectors. We then extend the axiomatisation of T(P), since the equivalence induced by the new operational semantics is weaker than that induced by the interaction semantics. This extension leads to canonical normal forms for all structures and to a simplification of the algorithm for the synthesis of connectors from Boolean coordination constraints.Comment: In Proceedings ICE 2013, arXiv:1310.401

Structure and Behaviour of Virtual Organisation Breeding Environments

This paper provides an outline of a formal approach that we are developing for modelling Virtual Organisations (VOs) and their Breeding Environments (VBEs). We propose different levels of representation for the functional structures and processes that VBEs and VOs involve, which are independent of the specificities of the infrastructures (organisational and technical) that support the functioning of VBEs. This allows us to reason about properties of tasks performed within VBEs and services provided through VOs without committing to the way in which they are implemented

Relating BIP and Reo

Coordination languages simplify design and development of concurrent systems. Particularly, exogenous coordination languages, like BIP and Reo, enable system designers to express the interactions among components in a system explicitly. In this paper we establish a formal relation between BI(P) (i.e., BIP without the priority layer) and Reo, by defining transformations between their semantic models. We show that these transformations preserve all properties expressible in a common semantics. This formal relation comprises the basis for a solid comparison and consolidation of the fundamental coordination concepts behind these two languages. Moreover, this basis offers translations that enable users of either language to benefit from the toolchains of the other.Comment: In Proceedings ICE 2015, arXiv:1508.0459

Improvement of bearing failure behaviour of T-shaped steel beam-reinforced concrete columns joints using perfbond plate connectors

[EN] For the joints composed of steel beams and reinforced concrete columns, shear failure and bearing failure are the key failure modes. The shear failure indicates stable hysteresis loop without the strength degradation. On the other hand, the bearing failure mode indicates large pinching and strength degration after the attainment of the maximum load.Accordingly, bearing failure in the joints should not be caused in RCS system.To improve the bearing failure behavior of S beam - RC column joint, joint details using perfobond plate connectors were proposed. Perfobond plate connectors were attached on the upper and bottom flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joints details experimentally and theoretically.Six specimens were tested. All specimens were T-shaped planar beam - column joints with 350mm square RC column and S beams with the width of 125mm and the depth of 300mm. The beams were all continuous through the column.Perfobond plate connectors were attached on the bottom flanges at right angles to the steel flange.Three holes were set up in the perfobond plate connectors. The experimental variable was the transverse reinforcement ratio of the joints. The transverse reinforcement ratio of the joints was 0.181% and 0.815%. For each transverse reinforcement ratio of the joints, specimen without the perfobond plate connectors, specimen with the perfobond plate connectors and specimen with the reinforcing bar inserted the hole of perfobond plate connectors were planned.For all specimens, the hysteresis loop showed the reversed S-shape. However, energy dissipation for specimens for specimens with perfobond plate connectors was larger than of specimen without perfobond plate connectors. Bearing strength of specimens with perfobond plate connectors was larger than that of specimen without perfobond plate connectors. From the test results, shear strength of concrete connector a hole was 0.7 times compression strength of concrete.On the other hand, shear strength of inserted reinforcing bar was 1.25 times shear strength of reinforcing bar.Based on the stress transferring mechanism and resistance mechanism of joints proposed by authors, the design formulae of joints with perfobond plate connectors were proposed.The predictions were shown to be in good agreement with the test results.Yoshida, M.; Nishimura, Y. (2018). Improvement of bearing failure behaviour of T-shaped steel beam-reinforced concrete columns joints using perfbond plate connectors. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 457-463. https://doi.org/10.4995/ASCCS2018.2018.7007OCS45746

Screw- and nail-gluing techniques for wood composite structures

Composite systems enhance the structural capacity and reliability of wood solutions for structures. With today engineered wood products and structural adhesives, high performing structures can be constructed. Hybrid assembly techniques that combine mechanical fasteners and an adhesive (screw- and nailgluing techniques) allow manufacturing large dimension composite structures with reasonable infrastructure. They also give full composite properties to the interlayers. Furthermore, these hybrid connections can experience ductility. This paper presents a research on small-scale glued assemblies which were manufactured using screw- and nail-gluing techniques. It discusses qualitative and quantitative analyses that confirmed the full-composite properties and ductility of the interlayers. The analyses also show that superposing the behaviour of both connectors is reasonable to predict the strength and slip modulus of hybrid connections. © 2007 Taylor & Francis Group, London

Runtime Enforcement for Component-Based Systems

Runtime enforcement is an increasingly popular and effective dynamic validation technique aiming to ensure the correct runtime behavior (w.r.t. a formal specification) of systems using a so-called enforcement monitor. In this paper we introduce runtime enforcement of specifications on component-based systems (CBS) modeled in the BIP (Behavior, Interaction and Priority) framework. BIP is a powerful and expressive component-based framework for formal construction of heterogeneous systems. However, because of BIP expressiveness, it remains difficult to enforce at design-time complex behavioral properties. First we propose a theoretical runtime enforcement framework for CBS where we delineate a hierarchy of sets of enforceable properties (i.e., properties that can be enforced) according to the number of observational steps a system is allowed to deviate from the property (i.e., the notion of k-step enforceability). To ensure the observational equivalence between the correct executions of the initial system and the monitored system, we show that i) only stutter-invariant properties should be enforced on CBS with our monitors, ii) safety properties are 1-step enforceable. Given an abstract enforcement monitor (as a finite-state machine) for some 1-step enforceable specification, we formally instrument (at relevant locations) a given BIP system to integrate the monitor. At runtime, the monitor observes and automatically avoids any error in the behavior of the system w.r.t. the specification. Our approach is fully implemented in an available tool that we used to i) avoid deadlock occurrences on a dining philosophers benchmark, and ii) ensure the correct placement of robots on a map.Comment: arXiv admin note: text overlap with arXiv:1109.5505 by other author