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This paper defines a suite of requirements for future hybrid cosimulation standards, and specifically provides guidance for development of a hybrid cosimulation version of the Functional Mockup Interface (FMI). A cosimulation standard defines interfaces that enable diverse simulation tools to interoperate. Specifically, one tool defines a component that forms part of a simulation model in another tool. We focus on components with inputs and outputs that are functions of time, and specifically on mixtures of discrete events and continuous time signals. This hybrid mixture is not well supported by existing cosimulation standards, and specifically not by FMI 2.0, for reasons that are explained in this paper. The paper defines a suite of test components, giving a mathematical model of an ideal behavior, plus a discussion of practical implementation considerations. The discussion includes acceptance criteria by which we can determine whether a standard supports definition of each component. In addition, we define a set of test compositions that define requirements for coordination between components, including consistent handling of timed events.

We prove invariance principles for phase separation lines in the two dimensional nearest neighbour Ising model up to the critical temperature and for connectivity lines in the general context of high temperature finite range ferromagnetic Ising models.

Abstract:The complexity of contemporary systems causes Systems Engineers great pains during early architectural design phases. Model-Based Systems Engineering (MBSE) proposes methodologies to deal with complexity and streamline design processes, but the penetration of the new approach is slow. This paper proposes a generic SysML based methodology for improving the Architectural Design phase of Systems and mitigate the barriers for MBSE adoption. The proposed methodology suggests an alternative way to formalize requirements, define design alternatives, automate design space exploration and examine optimization results in the original modeling format. A representative example is provided. A glossary is included at the end of the paper.

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Abstract This paper defines a suite of requirements for future hybrid cosimulation standards, and specifically provides guidance for development of a hybrid cosimulation version of the Functional Mockup Interface (FMI) standard. A cosimulation standard defines interfaces that enable diverse simulation tools to interoperate. Specifically, one tool defines a component that forms part of a simulation model in another tool. We focus on components with inputs and outputs that are functions of time, and specifically on inputs and outputs that are mixtures of discrete events and continuous time signals. This hybrid mixture is not well supported by existing cosimulation standards, and specifically not by FMI 2.0, for reasons that are explained in this paper. The paper defines a suite of test components, giving a mathematical model of an ideal behavior, plus a discussion of practical implementation considerations. The discussion includes acceptance criteria by which we can determine whether a standard supports definition of each component. In addition, the paper defines a set of test compositions of components. These compositions define requirements for coordination between components, including consistent handling of timed events.

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The Functional Mockup Interface (FMI) standard enables hybrid simulation of models from different tools. Such tools can have different underlying behavioral semantics, creating challenges when models are combined. A case in point is the combination of the Rhapsody tool, widely used to describe and implement discrete control behavior, and Modelica, widely used to describe continuous plant behavior.This paper describes a plugin we developed for exporting Functional Mockup Units (FMUs) from Rhapsody, and the results of combining generated FMUs with continuous models. When a Rhapsody FMU is used in a different environment, some basic assumptions on its behavior are challenged. We describe the semantic mismatches between the tools, to what extent they can be overcome, and what modelers need to do in order to preserve the intended semantics of an exported FMU.

Privacy-preserving solutions enable companies to offload confidential data to third-party services while fulfilling their government regulations. To accomplish this, they leverage various cryptographic techniques such as Homomorphic Encryption (HE), which allows performing computation on encrypted data. Most HE schemes work in a SIMD fashion, and the data packing method can dramatically affect the running time and memory costs. Finding a packing method that leads to an optimal performant implementation is a hard task. We present a simple and intuitive framework that abstracts the packing decision for the user. We explain its underlying data structures and optimizer, and propose a novel algorithm for performing 2D convolution operations. We used this framework to implement an inference operation over an encrypted HE-friendly AlexNet neural network with large inputs, which runs in around five minutes, several orders of magnitude faster than other state-of-the-art non-interactive HE solutions.