The User Interfaces Transition Diagram-Editor: A Tool to Simplify User-System Interaction Modeling

The User Interface Transition Diagram (UITD) is a formal modeling notation that simplifies the specification and design of user-system interactions. It is a valuable communication tool for technical and non-technical stakeholders during the requirements elicitation phase, as it provides a simple yet technically complete notation that is easy to understand. In this paper, we investigated the efficiency of creating UITDs using draw.io, a widely used diagramming software, compared to a dedicated UITD editor. We conducted a study to compare the time required to use each tool to complete the task of creating a medium size UITD, as well as the subjective ease of use and satisfaction of participants with the dedicated Editor. Our results show that the UITD editor is more efficient and preferred by participants, highlighting the importance of using specialized tools for creating formal models such as UITDs. The findings of this study have implications for software developers, designers, and other stakeholders involved in the specification and design of user-system interactions.

The asymptotic solution of particle growth in the convective undercooled melt driven by a biaxial straining flow

A dynamical system of particle growth in the con vective undercooled melt driven by a biaxial straining flow is modeled. A uniformly valid asymptotic solution for the in terface evolution in particle growth is obtained by means of the multiple variable expansion method. The analytical so lution as a function of both azimuth angle and polar angle shows that the interface shape of particle growth in the bi axial straining flow is significantly deformed by the biaxial straining flow. The biaxial straining flow results in higher lo cal growth rate near the surface where the flow comes in and leads to lower local growth rate near the surface where the flow goes out. Due to the difference in local growth rate, an initially spherical particle will evolve into a prolate barrel like shape in the biaxial straining flow.

Reachability analysis of web service compositions via NWA

In order to improve the design and implementation quality of web service compositions,formal methods are used to model them and certain properties are verified.WCFA （web service interface control flow automata）is used to model web services,especially the control flow and possible interactions with other web services.A web service composition consists of a set of interacting WCFA.The global behavior of web service compositions is captured by NWA（nested word automata）.A variation of the depth-first search algorithm is used to transform a set of WCFA into an NWA.State formulae and call stacks at each node of NWA are computed by a path-sensitive reachability analysis.Safety properties,call stack inspection properties and pre/post-conditions of service invocations are described by assertions.Then verification of these assertions is carried out by an automated SAT tool.

A Pragmatic Method to Determine Transient Stability Constrained with Interface Real Power Flow Limits via Power System Scenario Similarity

In practical power systems,operators generally keep interface flowing under the transient stability constrained with interface real power flow limits(TS-IRPFL)to guarantee transient stability of the system.Many methods of computing TS-IRPFL have been proposed.However,in practice,the method widely used to determine TS-IRPFL is based on selection and analysis of typical scenarios as well as scenario matching.First,typical scenarios are selected and analyzed to obtain accurate limits,then the scenario to be analyzed is matched with a certain typical scenario,whose limit is adopted as the forecast limit.In this paper,following the steps described above,a pragmatic method to determine TS-IRPFL is proposed.The proposed method utilizes data-driven tools to improve the steps of scenario selection and matching.First of all,we formulate a clear model of power system scenario similarity.Based on the similarity model,we develop a typical scenario selector by clustering and a scenario matcher by nearest neighbor algorithm.The proposed method is pragmatic because it does not change the existing procedure.Moreover,it is much more reasonable than the traditional method.Test results verify the validity of the method.

DNS analysis of incipient drop impact dynamics using an accurate level set method

A series of 2D direct numerical simulations were performed with an accurate level set method for single drop impacts.The adopted ACLS method was validated to be efficient with perfect mass conservation in both normal and oblique impacts.A square-root correction for neck bases was modified in accuracy as well as scope of applications.In addition,process of jet formation and evolution was studied to reveal internal dynamics in drop impacts.It's found that pressure gradient and vortex are coexisting and completive reasons for jet topology while the inclined angle has a significant effect on them.Mechanisms of jet formation and evolution are different in the front and back necks.With the help of PDF distribution and correction calculation,a compromise in the competition is observed.This work lays a solid foundation for further studies of dynamics in gas-liquid flows.

Simulation of flows with moving contact lines on a dual-resolution Cartesian grid using a diffuse-interface immersed-boundary method

In this paper, we investigate flows with moving contact lines on curved solid walls on a dual-resolution grid using a diffuse-interface immersed-boundary（DIIB） method. The dual-resolution grid, on which the flows are solved on a coarse mesh while the interface is resolved on a fine mesh, was shown to significantly improve the computational efficiency when simulating multiphase flows. On the other hand, the DIIB method is able to resolve dynamic wetting on curved substrates on a Cartesian grid, but it usually requires a mesh of high resolution in the vicinity of a moving contact line to resolve the local flow. In the present study, we couple the DIIB method with the dual-resolution grid, to improve the interface resolution for flows with moving contact lines on curved solid walls at an affordable cost. The dynamic behavior of moving contact lines is validated by studying drop spreading, and the numerical results suggest that the effective slip length λ_n can be approximated by 1.9Cn, where Cn is a dimensionless measure of the thickness of the diffuse interface. We also apply the method to drop impact onto a convex substrate, and the results on the dual-resolution grid are in good agreement with those on a single-resolution grid. It shows that the axisymmetric simulations using the DIIB method on the dual-resolution grid saves nearly 60% of the computational time compared with that on a single-resolution grid.

FRACTURE ASSESSMENT OF AN INTERFACE CRACK BETWEEN TWO DISSIMILAR MAGNETOELECTROELASTIC MATERIALS UNDER HEAT FLOW AND MAGNETOELECTROMECHANICAL LOADINGS

A magnetoelectrically permeable interface crack between two semi-infinite magnetoelectroelastic planes under the action of a heat flow and remote magnetoelectromechanical loadings is considered, where the assumption of frictionless contact between two dissimilar half-planes is adopted. Not only the solutions of the interface crack problem are presented in an explicit form, but also the general condition for the transition from a perfect thermal contact of two mag- netoelectroelastic bodies to their separation is given.