A tabulation of pipe length to diameter ratios as a function of Mach number and pressure ratios for compressible flow

Computer programs and resulting tabulations are presented of pipeline length-to-diameter ratios as a function of Mach number and pressure ratios for compressible flow. The tabulations are applicable to air, nitrogen, oxygen, and hydrogen for compressible isothermal flow with friction and compressible adiabatic flow with friction. Also included are equations for the determination of weight flow. The tabulations presented cover a wider range of Mach numbers for choked, adiabatic flow than available from commonly used engineering literature. Additional information presented, but which is not available from this literature, is unchoked, adiabatic flow over a wide range of Mach numbers, and choked and unchoked, isothermal flow for a wide range of Mach numbers

Comprehension of spacecraft telemetry using hierarchical specifications of behavior ⋆

Abstract. A key challenge in operating remote spacecraft is that ground operators must rely on the limited visibility available through spacecraft telemetry in order to assess spacecraft health and operational status. We describe a tool for processing spacecraft telemetry that allows ground operators to impose structure on received telemetry in order to achieve a better comprehension of system state. A key element of our approach is the design of a domain-specific language that allows operators to express models of expected system behavior using partial specifications. The language allows behavior specifications with data fields, similar to other recent runtime verification systems. What is notable about our approach is the ability to develop hierarchical specifications of behavior. The language is implemented as an internal DSL in the Scala programming language that synthesizes rules from patterns of specification behavior. The rules are automatically applied to received telemetry and the inferred behaviors are available to ground operators using a visualization interface that makes it easier to understand and track spacecraft state. We describe initial results from applying our tool to telemetry received from the Curiosity rover currently roving the surface of Mars, where the visualizations are being used to trend subsystem behaviors, in order to identify potential problems before they happen. However, the technology is completely general and can be applied to any system that generates telemetry such as event logs.

Runtime Verification of Temporal Properties over Out-of-order Data Streams

We present a monitoring approach for verifying systems at runtime. Our approach targets systems whose components communicate with the monitors over unreliable channels, where messages can be delayed or lost. In contrast to prior works, whose property specification languages are limited to propositional temporal logics, our approach handles an extension of the real-time logic MTL with freeze quantifiers for reasoning about data values. We present its underlying theory based on a new three-valued semantics that is well suited to soundly and completely reason online about event streams in the presence of message delay or loss. We also evaluate our approach experimentally. Our prototype implementation processes hundreds of events per second in settings where messages are received out of order.Comment: long version of the CAV 2017 pape

Runtime verification of parametric properties using SMEDL

Parametric properties are typical properties to be checked in runtime verification (RV). As a common technique for parametric monitoring, trace slicing divides an execution trace into a set of sub traces which are checked against non-parametric base properties. An efficient trace slicing algorithm is implemented in MOP. Another RV technique, QEA further allows for nested use of universal and existential quantification over parameters. In this paper, we present a methodology for parametric monitoring using the RV framework SMEDL. Trace slicing algorithm in MOP can be expressed by execution of a set of SMEDL monitors. Moreover, the semantics of nested quantifiers is encoded by a hierarchy of monitors for aggregating verdicts of sub traces. Through case studies, we demonstrate that SMEDL provides a natural way to monitor parametric properties with more potentials for flexible deployment and optimizations

A Homogeneous Actor-Based Monitor Language for Adaptive Behaviour

This paper describes a structured approach to encoding monitors in an actor language. Within a configuration of actors, each of which publishes a history, a monitor is an independent actor that triggers an action based on patterns occurring in the histories. We define a monitor language based on linear temporal logic and show how it can be homogeneously embedded within an actor language. The approach is demonstrated through a number of examples and evaluated in terms of a real-world actor-based simulation

Consequences of Kaizen Practices in MSMEs in the Philippines: The Case of the Manufacturing Productivity Extension Program (MPEX)

The Manufacturing Productivity Extension Program (MPEX) is a fully subsidized public-instigated productivity improvement program directed toward the micro, small, and medium enterprise (MSME) sector. While not advertised and packaged as a Kaizen initiative, it has all the elements of the Kaizen philosophy. Based on survey responses from 64 MPEX beneficiaries and 47 non-MPEX beneficiaries, the study showed that MPEX increased the number of product lines implying that Kaizen practice leads to product innovation among firms. Due to data and confounding issues, significant difference in productivity in terms of number of workers and sales per worker was not established. Firm asset size was implied to influence the capability to implement Kaizen. Regulatory compliance and customer demand requirements and entrepreneurial capacity are catalysts for enabling, adopting, and sustaining Kaizen implementation

A foundation for runtime monitoring

Runtime Verification is a lightweight technique that complements other verification methods in an effort to ensure software correctness. The technique poses novel questions to software engineers: it is not easy to identify which specifications are amenable to runtime monitor-ing, nor is it clear which monitors effect the required runtime analysis correctly. This exposition targets a foundational understanding of these questions. Particularly, it considers an expressive specification logic (a syntactic variant of the modal μ-calculus) that is agnostic of the verification method used, together with an elemental framework providing an operational semantics for the runtime analysis performed by monitors. The correspondence between the property satisfactions in the logic on the one hand, and the verdicts reached by the monitors performing the analysis on the other, is a central theme of the study. Such a correspondence underpins the concept of monitorability, used to identify the subsets of the logic that can be adequately monitored for by RV. Another theme of the study is that of understanding what should be expected of a monitor in order for the verification process to be correct. We show how the monitor framework considered can constitute a basis whereby various notions of monitor correctness may be defined and investigated.peer-reviewe

A Foundation for Runtime Monitoring

Runtime Verification is a lightweight technique that complements other verification methods in an effort to ensure software correctness. The technique poses novel questions to software engineers: it is not easy to identify which specifications are amenable to runtime monitoring, nor is it clear which monitors effect the required runtime analysis correctly. This exposition targets a foundational understanding of these questions. Particularly, it considers an expressive specification logic (a syntactic variant of the mmucalc) that is agnostic of the verification method used, together with an elemental framework providing an operational semantics for the runtime analysis performed by monitors. The correspondence between the property satisfactions in the logic on the one hand, and the verdicts reached by the monitors performing the analysis on the other, is a central theme of the study. Such a correspondence underpins the concept of monitorability, used to identify the subsets of the logic that can be adequately monitored for by RV. Another theme of the study is that of understanding what should be expected of a monitor in order for the verification process to be correct. We show how the monitor framework considered can constitute a basis whereby various notions of monitor correctness may be defined and investigated