Long Duration Exposure Facility (LDEF) optical systems SIG summary and database

The main objectives of the Long Duration Exposure Facility (LDEF) Optical Systems Special Investigative Group (SIG) Discipline are to develop a database of experimental findings on LDEF optical systems and elements hardware, and provide an optical system overview. Unlike the electrical and mechanical disciplines, the optics effort relies primarily on the testing of hardware at the various principal investigator's laboratories, since minimal testing of optical hardware was done at Boeing. This is because all space-exposed optics hardware are part of other individual experiments. At this time, all optical systems and elements testing by experiment investigator teams is not complete, and in some cases has hardly begun. Most experiment results to date, document observations and measurements that 'show what happened'. Still to come from many principal investigators is a critical analysis to explain 'why it happened' and future design implications. The original optical system related concerns and the lessons learned at a preliminary stage in the Optical Systems Investigations are summarized. The design of the Optical Experiments Database and how to acquire and use the database to review the LDEF results are described

The Visvalingam algorithm: metrics, measures and heuristics

This paper provides the background necessary for a clear understanding of forthcoming papers relating to the Visvalingam algorithm for line generalisation, for example on the testing and usage of its implementations. It distinguishes the algorithm from implementation-specific issues to explain why it is possible to get inconsistent but equally valid output from different implementations. By tracing relevant developments within the now-disbanded Cartographic Information Systems Research Group (CISRG) of the University of Hull, it explains why a) a partial metric-driven implementation was, and still is, sufficient for many projects but not for others; b) why the Effective Area (EA) is a measure derived from a metric; c) why this measure (EA) may serve as a heuristic indicator for in-line feature segmentation and model-based generalisation; and, d) how metrics may be combined to change the order of point elimination. The issues discussed in this paper also apply to the use of other metrics. It is hoped that the background and guidance provided in this paper will enable others to participate in further research based on the algorithm

Why Performance Testing

This paper introduces Benefits of performance testing in organizations. To understand the importance, it is very necessary to know what Performance is testing, why it should be or when it should be performed. Performance testing means to validate the applications/ systems reliability, scalability, stability. If testing is not performed properly then it can produce catastrophic results. Keywords: Performance Testing, HP Load runner, Load testing, Stress Testin

Symmetry Breaking in Bose-Einstein Condensates

A gaseous Bose-Einstein condensate (BEC) offers an ideal testing ground for studying symmetry breaking, because a trapped BEC system is in a mesoscopic regime, and situations exist under which symmetry breaking may or may not occur. Investigating this problem can explain why mean-field theories have been so successful in elucidating gaseous BEC systems and when many-body effects play a significant role. We substantiate these ideas in four distinct situations: namely, soliton formation in attractive BECs, vortex nucleation in rotating BECs, spontaneous magnetization in spinor BECs, and spin texture formation in dipolar BECs.Comment: Submitted to the proceedings of International Conference on Atomic Physics 200

Simulated time for testing railway interlockings with TTCN-3

In this report, we first give an overview of software systems based on Vital Processor Interlocking (VPI). Interlockings guarantee safety of railway control systems, so testing these software systems is a key issue. We show why testing such systems with real time and scaled time is inefficient. We also provide a time semantics for simulated time that is more suitable for testing VPI's software. We provide a solution that allows simulated time for TTCN-3 test systems. TTCN-3 is a standard language for specifying and executing test suites. In the context of the TT-MEDAL project, TTCN-3 is applied to various domains, in particular to testing railway and automotive systems. TTCN-3 supports real-time and scaled-time testing but not simulated-time testing. The solution is based on a distributed termination detection algorithm that we extend to provide the main ingredients of simulated time: idleness detection and correct time progress. We implemented our solution as a TTCN-3 module and several Java classes that can be reused for testing other systems that have characteristics similar to those of VPI

How Should Life Support Be Modeled and Simulated?

Why do most space life support research groups build and investigate large models for systems simulation? The need for them seems accepted, but are we asking the right questions and solving the real problems? The modeling results leave many questions unanswered. How then should space life support be modeled and simulated? Life support system research and development uses modeling and simulation to study dynamic behavior as part of systems engineering and analysis. It is used to size material flows and buffers and plan contingent operations. A DoD sponsored study used the systems engineering approach to define a set of best practices for modeling and simulation. These best practices describe a systems engineering process of developing and validating requirements, defining and analyzing the model concept, and designing and testing the model. Other general principles for modeling and simulation are presented. Some specific additional advice includes performing a static analysis before developing a dynamic simulation, applying the mass and energy conservation laws, modeling on the appropriate system level, using simplified subsystem representations, designing the model to solve a specific problem, and testing the model on several different problems. Modeling and simulation is necessary in life support design but many problems are outside its scope

The Dynamical Nonlocality of Neutral Kaons and the Kaonic Quantum Eraser

Testing quantum foundations for systems in high energy physics gets currently more and more attention e.g. witnessed for entangled neutral K-mesons by the approved programme of the KLOE collaboration at the accelerator facility DAPHNE (Frascati, Italy). We focus on this quantum system in high energy physics and discuss two topics, Bell inequalities and the kaonic quantum eraser, and show how the neutral kaon system differs from systems of ordinary matter and light. In detail, we show a relation of the imbalance of matter and antimatter to the violation of a Bell inequality and discuss another Bell inequality which is maximally violated for a non-maximally entangled state though neutral kaons can be considered as two state systems. We compare in general this system in high energy physics with bipartite qudits. Last but not least we review the quantum marking and eraser procedure and explain why neutral kaons offer more eraser possibilities than usual quantum systems.Comment: 10 pages, 1 figures, to be published in AIP Conference Proceedings: Advances in Quantum Theory, Vaexjoe 201

Spacecraft Testing Programs: Adding Value to the Systems Engineering Process

Testing has long been recognized as a critical component of spacecraft development activities - yet many major systems failures may have been prevented with more rigorous testing programs. The question is why is more testing not being conducted? Given unlimited resources, more testing would likely be included in a spacecraft development program. Striking the right balance between too much testing and not enough has been a long-term challenge for many industries. The objective of this paper is to discuss some of the barriers, enablers, and best practices for developing and sustaining a strong test program and testing team. This paper will also explore the testing decision factors used by managers; the varying attitudes toward testing; methods to develop strong test engineers; and the influence of behavior, culture and processes on testing programs. KEY WORDS: Risk, Integration and Test, Validation, Verification, Test Program Developmen