Multi-stakeholder Interactive Simulation for Federated Satellite Systems

Federated satellite systems (FSS) are a new class of space-based systems which emphasize a distributed architecture. New information exchanging functions among FSS members enable data transportation, storage, and processing as on-orbit services. As a system-of-systems, however there are significant technical and social barriers to designing a FSS. To mitigate these challenges, this paper develops a multi-stakeholder interactive simulation for use in future design activities. An FSS simulation interface is defined using the High Level Architecture to include orbital and surface assets and associated transmitters, receivers, and signals for communication. Sample simulators (federates) using World Wind and Orekit open source libraries are applied in a prototype simulation (federation). The application case studies a conceptual FSS using the International Space Station (ISS) as a service platform to serve Earth-observing customers in sun-synchronous orbits (SSO). Results identify emergent effects between FSS members including favorable ISS power conditions and potential service bottlenecks to serving SSO customers

Bounding the End-to-End Execution Time in Distributed Real-Time Systems: Arguing the case for Deterministic Networks in Lingua Franca

Designing and implementing distributed systems with real-time requirements quickly reveal the complexity of handling time and logic across multiple systems. As data traverse a network, it is subjected to variable delay due to interfering traffic and variable load on network components. This introduces an element of non-determinism in execution time for distributed algorithms, which translates into increased error logic and pessimistic worst-case estimates. Over the next few years, it is expected that Cyber-Physical Systems will see many new use cases, and the network connecting these will play an ever more important role. Combined with the onset of the fourth industrial revolution, IEEEs Time Sensitive Networking, IETFs Deterministic Networking, and 3GPPs Ultra Reliable Low Latency profile will play a vital role in realizing these systems. Coordination languages such as Lingua Franca can offer a substantial contribution to the design process and implementation of distributed systems such as Cyber-Phyiscal Systems, both through its model of computation which elevates time to a first-class citizen and with its support for distributed models. In this paper, we show that by introducing deterministic network channels with a fixed delay, the worst-case execution time is not increased whereas the variance in total execution time from start to finish is greatly reduced. For a coordination language such as LF, this means that we can analyze a system using much tighter delay bounds for network traffic, which in turn can yield better resource utilization.publishedVersio

Microgrid Protection Student Laboratory: Human-Machine Interface and SCADA Database

The electric utility system, a ubiquitous and fundamental component of modern life, has changed more in the last 20 years than the last 100. With more homes and businesses installing distributed energy resources (DERs) such as solar panels, battery storage, and other intermittent sources, massive changes need to take place in the electric transmission and distribution systems. Engineers must develop a new skill set for a modern utility industry. This project summarizes a component for a new laboratory class aimed at power engineering students at Cal Poly which supports the laboratory through the creation of a human-machine interface (HMI) and SCADA data concentrator. This HMI streamlines data-collection for laboratory experiments, giving instructors more flexibility when designing labs as data collection procedures are simplified, while the SCADA system serves as a platform to automate system processes in the microgrid, enabling the continuation of this project, developing methodology to automate and control the microgrid laboratory and create subsequent lab experiments on the control of the syste

Potential applications of simulation modelling techniques in healthcare: lessons learned from aerospace and military

The Aerospace and Military areas are to do with complex missions and situations. Modelling and Simulation (M&S) has been applied in many areas of defence ranging from space sciences, satellite engineering to multi-warfare (air warfare, undersea warfare), air & missile defence, acquisition, tactical military trainings & exercises, national security analysis and strategic decision making & planning, etc. The application of simulation modelling techniques in healthcare would improve the provision of healthcare services; however, their application has been much relatively feeble in the healthcare sector as compared to the defence sector. This paper presents results from a systematic literature survey on applications of modelling simulation techniques in the Aerospace & Military. The knowledge gained or lessons learned from the survey were finally used to analyze the potential applications of the simulation modelling techniques to the healthcare sector. Results show that in the defence sector, Distributed Simulation has now become a widely adopted technique. However, System Dynamics (SD) and Discrete Event Simulation (DSE) have also gained relative attention. From this survey it becomes clear that various simulation modelling techniques are useful for specific purposes and have potential applications in the healthcare sector

Design as conversation with digital materials

This paper explores Donald Schön's concept of design as a conversation with materials, in the context of designing digital systems. It proposes material utterance as a central event in designing. A material utterance is a situated communication act that depends on the particularities of speaker, audience, material and genre. The paper argues that, if digital designing differs from other forms of designing, then accounts for such differences must be sought by understanding the material properties of digital systems and the genres of practice that surround their use. Perspectives from human-computer interaction (HCI) and the psychology of programming are used to examine how such an understanding might be constructed.</p

Software acquisition: a business strategy analysis

The paper argues that there are new insights to be gained from a strategic analysis of requirements engineering. The paper is motivated by a simple question: what does it take to be a world class software acquirer? The question has relevance for requirements engineers because for many organisations market pressures mean that software is commonly acquired rather than developed from scratch. The paper builds on the work of C. H. Fine (1998) who suggests that product, process and supply chain should be designed together, i.e., 3D concurrent engineering. Using a number of reference theories, it proposes a systematic way of carrying out 3D concurrent engineering. The paper concludes that the critical activity in supply chain design is the design of the distribution of skills and the nature of contract