Autonomous software: Myth or magic?

We discuss work by the eSTAR project which demonstrates a fully closed loop autonomous system for the follow up of possible micro-lensing anomalies. Not only are the initial micro-lensing detections followed up in real time, but ongoing events are prioritised and continually monitored, with the returned data being analysed automatically. If the ``smart software'' running the observing campaign detects a planet-like anomaly, further follow-up will be scheduled autonomously and other telescopes and telescope networks alerted to the possible planetary detection. We further discuss the implications of this, and how such projects can be used to build more general autonomous observing and control systems.Comment: 3 pages, 4 figures, to appear in proceedings of Hot-wiring the Transient Universe (HTU) 2007, Astronomische Nachrichten, March 200

SURE reliability analysis: Program and mathematics

The SURE program is a new reliability analysis tool for ultrareliable computer system architectures. The computational methods on which the program is based provide an efficient means for computing accurate upper and lower bounds for the death state probabilities of a large class of semi-Markov models. Once a semi-Markov model is described using a simple input language, the SURE program automatically computes the upper and lower bounds on the probability of system failure. A parameter of the model can be specified as a variable over a range of values directing the SURE program to perform a sensitivity analysis automatically. This feature, along with the speed of the program, makes it especially useful as a design tool

Model reduction by trimming for a class of semi-Markov reliability models and the corresponding error bound

Semi-Markov processes have proved to be an effective and convenient tool to construct models of systems that achieve reliability by redundancy and reconfiguration. These models are able to depict complex system architectures and to capture the dynamics of fault arrival and system recovery. A disadvantage of this approach is that the models can be extremely large, which poses both a model and a computational problem. Techniques are needed to reduce the model size. Because these systems are used in critical applications where failure can be expensive, there must be an analytically derived bound for the error produced by the model reduction technique. A model reduction technique called trimming is presented that can be applied to a popular class of systems. Automatic model generation programs were written to help the reliability analyst produce models of complex systems. This method, trimming, is easy to implement and the error bound easy to compute. Hence, the method lends itself to inclusion in an automatic model generator

Verifying Algorithms for Autonomous Aircraft by Simulation Generalities and Example

An open question in Air Traffic Management is what procedures can be validated by simulation where the simulation shows that the probability of undesirable events is below the required level at some confidence level. The problem is including enough realism to be convincing while retaining enough efficiency to run the large number of trials needed for high confidence. The paper first examines the probabilistic interpretation of a typical requirement by a regulatory agency and computes the number of trials needed to establish the requirement at an equivalent confidence level. Since any simulation is likely to consider only one type of event and there are several types of events, the paper examines under what conditions this separate consideration is valid. The paper establishes a separation algorithm at the required confidence level where the aircraft operates under feedback control as is subject to perturbations. There is a discussion where it is shown that a scenario three of four orders of magnitude more complex is feasible. The question of what can be validated by simulation remains open, but there is reason to be optimistic

Designing Fault-Injection Experiments for the Reliability of Embedded Systems

This paper considers the long-standing problem of conducting fault-injections experiments to establish the ultra-reliability of embedded systems. There have been extensive efforts in fault injection, and this paper offers a partial summary of the efforts, but these previous efforts have focused on realism and efficiency. Fault injections have been used to examine diagnostics and to test algorithms, but the literature does not contain any framework that says how to conduct fault-injection experiments to establish ultra-reliability. A solution to this problem integrates field-data, arguments-from-design, and fault-injection into a seamless whole. The solution in this paper is to derive a model reduction theorem for a class of semi-Markov models suitable for describing ultra-reliable embedded systems. The derivation shows that a tight upper bound on the probability of system failure can be obtained using only the means of system-recovery times, thus reducing the experimental effort to estimating a reasonable number of easily-observed parameters. The paper includes an example of a system subject to both permanent and transient faults. There is a discussion of integrating fault-injection with field-data and arguments-from-design

Perceptions of Czech and Slovak participants of the usefulness of the Iowa State University Farm Management in a Market Economy Workshop

The purpose of this investigation was to assess the perception of the participants who attended Farm Management in a Market Economy (Workshop I), which was presented at the three agriculture universities in the Czech and Slovak Federal Republic. The workshop was designed to assist them in their efforts in moving from a centrally controlled economy (society) to a market economy (society). Objectives of the study were to determine: (1) to what extent the participants were able to understand the information presented in the workshop; (2) the usefulness of the workshop to the participants in their efforts to understand a market economy; and (3) to what extent the workshop was effectively planned and organized;For the study\u27s first objective, 99.2 percent of the respondents indicated they completely understood the information or they understood most, but not all, of the information presented;The composite overall mean score for the second objective was 4.25 (useful to very useful). The respondents indicated that they felt that the question and response period was the most useful. Least useful were audio visual presentations;For the study\u27s third objective, that of assessing if the participants felt the workshop was effectively planned and organized, the overall mean score for this objective was 4.06 (more than adequate);Significant differences (=.05) were observed among group means for the objectives when the respondents were grouped by age, professional responsibility, years in current position, and location in which they participated in the workshop;Several of the participants indicated that they felt the workshop was very well presented and several indicated they were going to try to use the information to make changes in their work. The most striking example was given by a participant from the Nitra workshop, Jan\u27 Goldsmith. On Thursday, during the open discussion period set aside for evaluation comments, he publicly announced, Because of this workshop, I quit my job on the cooperative farm last night and I am going to be a private farmer. Participants also indicated that they felt the workshop was useful to them in their efforts to understand a market economy

ABSORPTION AND UTILISATION OF NATURAL AND SYNTHETIC ASTAXANTHIN FORMS IN SALMONID NUTRITION

Consumer preference for commercially reared fish products that resemble their wild counterparts has resulted in the supplementation of pigments called carotenoids into aquafeeds to promote a pink-red colour in the flesh of salmonid fish. To date synthetic forms of these pigments have been commonly utilised to achieve this desired colouration, with the carotenoid astaxanthin being the regular choice for the feed manufacturer. However, increase in consumer demand for farmed fish products reared on natural feed additives has evoked an interest in natural sources of astaxanthin that could be successfully used to pigment salmonid fish efficiently. In the current study, the microalga Haemalococcus pluvialis has been assessed as a potential feed supplement to pigment the flesh of rainbow trout (Oncorhynchus mykiss). More specifically, those natural characteristics that may well limit the absorption and utilisation of astaxanthin from this source have been assessed individually and discussed from a physiological standpoint. The cell wall of Haemalococcus pluvialis when cracked efficiently presents no limitation to the absorption and utilisation of astaxanthin from this source. Indeed, the cell wall remnants help to prevent oxidation of astaxanthin in the feed compared to cell wall free extracts of carotenoid from the same source. However, esterified astaxanthin (which this algae predominantly contains) is not absorbed as efficiently as unesterified synthetic astaxanthin. Furthermore, the extent of esterification is negatively related to the absorption of astaxanthin. Regional variation in ester hydrolysis along the gastrointestinal tract combined with gut transit time of the ingested feed may explain these limitations. However, despite limitations in absorption, the muscle deposition of astaxanthin supplied as esters does not significantly differ from the unesterified form. The optical purity of astaxanthin esters from this source does not prejudice the final deposition of astaxanthin in fish tissues. An in vitro model has been developed to assess the absorption of astaxanthin at the intestinal level in salmonid fish in order to define absorption characteristics of carotenoids under different abiotic and biotic conditions. The absorption of astaxanthin seems to occur in a linear passive manner into the intestinal tissue. Although size of the fish does not affect the absorption of astaxanthin, temperature does have a significant effect. Although there were no significant differences in absorption between Atlantic salmon (Salmo salar) and rainbow trout, absorption tended to be greater in the latter species and merits further study.Carotenoid Research Group, Department of Biological sciences, Liverpool John Moores University, Liverpoo

A Framework for Delivering Contextually Appropriate Opportunities for Warfighter Practice

Computer-based modeling and simulation has been a training staple in the military domain since the first aircraft simulators were adopted. More recently, virtual environments based on modeling, simulation and serious games, have introduced relatively low-cost, yet high value additions to the learning environment. As these virtual environments have proliferated, many researchers have investigated the relationship between theoretical foundations of learning, learner development and content delivery, and applied their findings in an attempt to bolster learning, yet performance deficiencies continue to exist. This study asserts that performance deficiencies exist in part because of insufficient contextually appropriate opportunities to practice. This work is multi-disciplinary in nature. Its foundation is modeling and simulation engineering; the use of technology to deliver training. Educational psychology and human factors concepts explain the theoretical basis for modeling and simulation as an effective training delivery agent. The study\u27s thesis is that a framework for delivering contextually appropriate opportunities for warfighter practice can be applied to discover whether modeling, simulation and game-based virtual environments have the potential to improve individual performance for learners beyond the Novice Stage (e.g., Competent Stage) of skills acquisition. Furthermore, this conceptually appropriate practice (CAP) framework can be used to assess the potential of low fidelity virtual environments to provide targeted practice and to improve individual performance, not only during training in high-fidelity virtual environments (near transfer) but also in the live environment (far transfer). To evaluate the thesis, this study investigates the relationship of technology and learning science, and features an empirical evaluation of training effectiveness afforded by delivering additional training repetitions using both low-fidelity virtual environment simulator systems and high-fidelity aircraft simulators