Autonomous power expert system

The goal of the Autonomous Power System (APS) program is to develop and apply intelligent problem solving and control technologies to the Space Station Freedom Electrical Power Systems (SSF/EPS). The objectives of the program are to establish artificial intelligence/expert system technology paths, to create knowledge based tools with advanced human-operator interfaces, and to integrate and interface knowledge-based and conventional control schemes. This program is being developed at the NASA-Lewis. The APS Brassboard represents a subset of a 20 KHz Space Station Power Management And Distribution (PMAD) testbed. A distributed control scheme is used to manage multiple levels of computers and switchgear. The brassboard is comprised of a set of intelligent switchgear used to effectively switch power from the sources to the loads. The Autonomous Power Expert System (APEX) portion of the APS program integrates a knowledge based fault diagnostic system, a power resource scheduler, and an interface to the APS Brassboard. The system includes knowledge bases for system diagnostics, fault detection and isolation, and recommended actions. The scheduler autonomously assigns start times to the attached loads based on temporal and power constraints. The scheduler is able to work in a near real time environment for both scheduling and dynamic replanning

Autonomous power system intelligent diagnosis and control

The Autonomous Power System (APS) project at NASA Lewis Research Center is designed to demonstrate the abilities of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution hardware. Knowledge-based software provides a robust method of control for highly complex space-based power systems that conventional methods do not allow. The project consists of three elements: the Autonomous Power Expert System (APEX) for fault diagnosis and control, the Autonomous Intelligent Power Scheduler (AIPS) to determine system configuration, and power hardware (Brassboard) to simulate a space based power system. The operation of the Autonomous Power System as a whole is described and the responsibilities of the three elements - APEX, AIPS, and Brassboard - are characterized. A discussion of the methodologies used in each element is provided. Future plans are discussed for the growth of the Autonomous Power System

Enhancement of polyelectrolyte precipitation through the genetic fusion of charged polypeptides to enzymes

The focus of this work was to investigate the enhancement of polyelectrolyte precipitation through the genetic alteration of the target protein. The dissertation is divided into three primary chapters: a literature review of precipitation techniques which display high selectivity, experimental work including the characterization and precipitation of the fusion enzymes, and modeling of the precipitation process;The literature review of selective precipitation techniques focuses on those techniques for which relatively high purifications can be achieved. The techniques include precipitation with polyelectrolytes, affinity ligands, metal ions, and protein-binding dyes. Topics discussed include the mechanisms of selectivity and precipitation, degrees of purification which can be obtained, practical application of the precipitants, enhancement through genetic engineering, and other considerations such as mixing and recovery of the product;For the experimental work, carboxylic terminus fusions of poly(aspartic acid) were made using two proteins, [beta]-galactosidase and glucoamylase. Poly(arginine) fusions were also made with [beta]-galactosidase. The polyelectrolytes investigated were polyethyleneimine and poly(acrylic acid). Precipitation was found to be enhanced as the number of charged fusion peptides increased. An optimal tail length was observed, beyond which the addition of further peptides did not result in any further enhancement of precipitation. Activity could be quantitatively recovered from precipitates of all fusion enzymes except for the poly(arginine)-[beta]-galactosidase fusions. The degree of precipitation for each of the glucoamylase fusions was found to decrease upon increasing ionic strength. The [beta]-galactosidase control and native enzymes displayed the same behavior. The [beta]-galactosidase fusion enzymes actually displayed an increase in the degree of precipitation upon increasing the ionic strength;A model was developed to account for the presence of the charged fusion peptides in polyelectrolyte precipitation. The model is based on multiple equilibrium binding with cooperativity effects and multiple association constants. The model treats the enzyme and the fusion tail as having separate association constants. Electrostatic cooperativity is not evidenced for the binding of these negatively charged proteins to positively charged, highly branched polyethyleneimine. Experimental results for the monomeric control enzyme correlate well with model predictions. For the tailed enzymes, however, corrections for their enhanced solubility at low polyelectrolyte dosages had to be made. For the tetrameric enzyme, it is proposed that the formation of an interconnected matrix results from the multiple tails on an enzyme strongly binding to multiple polyelectrolytes. Such a mechanism would account for the increase in precipitation with increasing ionic strength if the increase in ionic strength is not sufficient to disrupt protein-polyelectrolyte binding but can reduce the electrostatic barrier to formation of a matrix of complexes carrying a net charge

Analysis of real-world passwords for social media sites

Textual passwords have dominated all other entity authentication mechanisms since they were introduced in the early 1960’s. Despite an inherent weakness against social engineering, keylogging, shoulder surfing, dictionary, and brute-force attacks, password authentication continues to grow as the Internet expands. Existing research on password authentication proves that dictionary attacks are successful because users make poor choices when creating passwords. To make passwords easier to remember, users select character strings that are shorter in length and contain memorable content, like personal identity information, common words found in a dictionary, backward spellings of common words, recognizable sequences, and easily guessed mnemonic phrases. A number of these studies identify weaknesses found in passwords on social media sites [1] [2] [3] [4] [5]. However, this body of work fails to explore whether users choose more secure passwords on accounts that protect their professional online identity than they choose on accounts that are used for personal entertainment. In this study, we first cracked passwords from the over 6.4 million unsalted, SHA-1 hashed passwords stolen from the professional, social media site, LinkedIn. Next, we analyzed the length, character set composition, and entropy score of the passwords recovered. Then, we compared our results to the analysis of passwords performed by Weir, et al. on the RockYou! dataset to determine whether professionals protecting their online presence chose wiser passwords than social media site users who play online games. In our analysis we found that the users of the professional, social media site, LinkedIn, chose more secure passwords than the users of the social media gaming site, RockYou!. LinkedIn passwords contained a greater percentage of numbers, special characters, and uppercase letters than RockYou!. We also found that the LinkedIn passwords utilized special characters more frequently, but RockYou! passwords applied special character less predictably

SAILS: : Spectral Analysis In Linear Systems

Autoregressive modelling provides a powerful and flexible parametric approach to modelling uni- or multi-variate time-series data. AR models have mathematical links to linear time- invariant systems, digital filters and Fourier based frequency analyses. As such, a wide range of time-domain and frequency-domain metrics can be readily derived from the fitted au- toregressive parameters. These approaches are fundamental in a wide range of science and engineering fields and still undergoing active development. SAILS (Spectral Analysis in Linear Systems) is a python package which implements such methods and provides a basis for both the straightforward fitting of AR models as well as exploration and development of newer methods, such as the decomposition of autoregressive parameters into eigenmodes

Athlete Monitoring in Rugby League: a focus on the conceptualisation, implementation and utilisation of a wellness questionnaire.

Wellness questionnaires are often used to monitor athletes to gain an understanding of the responses to training and gameplay. This thesis presents original information concerning the conceptualisation, implementation and use of wellness questionnaires with a focus on the sport of rugby league. The overall aim of the thesis was to investigate the use and implementation of a wellness questionnaire with the goal of developing a framework for successful implementation. Whilst wellness questionnaires appear to be a popular method for evaluating the response to training and readiness to perform, there are limited details on the type of questionnaires used by practitioners. Study 1 investigated the use and implementation of current wellness questionnaires across a range of high- performance sports. The study examined if there is commonality amongst the use of wellness questionnaires with regard to customised designs, scales, items and the levels of implementation achieved. Based on a review of the literature and practical experience of the research team, an online survey was constructed consisting of 23 questions. 122 participants recruited through the network of the research team completed the survey. Analysis of the responses indicated that customised wellness questionnaires were prevalent and used by the majority of respondents (74%) each training day. These questionnaires differed in the types of scale, items and analysis techniques used. With regard to implementation, the majority reported completion rates above 75%. However, issues associated with the questionnaire, team resources, issuing reminders and generating buy-in were evident. In a follow up to the main survey, practitioners identified five key themes needed for successful implementation which were labelled the Implementation Outcomes. These outcomes can be used to evaluate the success of the implementation and use of wellness questionnaires. Following on from study 1 it was necessary to give an in-depth focus on the implementation and use of wellness questionnaires within a rugby league context. Previous research has identified factors associated with the measure and the social environment that influence questionnaire use in a range of different sports (Saw, Main, & Gastin, 2015b). Therefore, study 2 interviewed players and staff (n = 20) within a European Super League team to examine the factors that were relevant within their context. Reported Implementation Factors were identified across the organisation (e.g. team resources), the measure (e.g. mode and accessibility of the wellness questionnaire), inter-personal (e.g. reminders), and individual level (e.g. player buy-in). The factors were consistent with previous research into implementation and several novel higher order factors were identified residing within the organisation (context, process, personalisation and coaching staff). Twenty-three original lower order themes specific to a rugby league environment were identified. Implementation factors manifested across data collection, analysis and decision-making. The findings lend support to the use of a social ecological model to identify factors influencing wellness questionnaire use in rugby league. The customised wellness questionnaires which have been used within rugby league research give limited insight into the questionnaire development and validation. No wellness questionnaire exists that has been thoroughly validated and tested within a rugby league environment. Study 3 subsequently sought to develop and validate a new wellness questionnaire for use in rugby league. This study involved four phases of development to examine face, content and concurrent validity in addition to the reliability of the questionnaire. The construction of the new questionnaire also concerned the appraisal as to the ecological fit of using wellness questionnaires within the host setting. Taking into account the findings of studies 1 and 2, consideration was given to implementation in the construction of the questionnaire. Aligned with current guidelines, assessments were made to determine the purpose of using the wellness questionnaire, if there was buy-in from the stakeholders and if it was feasible to implement. The newly developed 9-item wellness questionnaire was deemed valid, reliable and acceptable to use within rugby league environments. The study comprehensively demonstrates the process of developing and validating a wellness questionnaire above and beyond other previously used and published questionnaires. Study 4 used the newly developed questionnaire to assess player wellness in conjunction with external and internal load in a European Super League team. There is a lack of normative wellness data, including details on how to monitor, analyse and interpret this data at team and individual levels. Players completed a wellness questionnaire across 68 consecutive days of the rugby league season (Super 8s to Grand Final). Global positioning system data and session rating of perceived exertion was recorded for training and games. Results indicate the new wellness questionnaire is sensitive to detect change and identifies a high variation in wellness data the day after game-play. This questionnaire is recommended to collect data at matchdays +1, +3, +4, and +6. Results support the findings of previous studies which suggest that it takes at least 4 days post-game to recover to pre-game levels of wellness. Wellness questionnaires should be used in conjunction with training load data and results found that post-game wellness strongly correlated with the number of tackles in rugby league games, r(6) = 0.80 p= 0.17. Furthermore, when tackles were combined with high speed running metres wellness was significantly predicted post-game, F(2, 5) = 17.760, p = .005, adj. R2 = .83. Wellness scores showed high inter and intra individual variability. The study provides case study examples analysing team and individual player wellness, suggesting the use of z- scores and visualisations using statistical process control charts and radar plots. The findings of this thesis lend support to the use of wellness questionnaires in rugby league and high- performance sport, providing they are appropriately developed, validated and implemented. The final written chapter presents a conceptual model named the Successful Implementation Framework which aims to guide practitioner implementation of wellness questionnaires. The framework brings together aspects established in this thesis including the Implementation Considerations (study 3), Implementation Areas (study 2), Implementation Factors (study 2), Implementation Outcomes (study 1) and recommendations for use (study 4)

Single-Molecule Junction Conductance through Diaminoacenes

The study of electron transport through single molecules is essential to the development of molecular electronics. Indeed, trends in electronic conductance through organic nanowires have emerged with the increasing reliability of electron transport measurements at the single-molecule level. Experimental and theoretical work has shown that tunneling distance, HOMO-LUMO gap and molecular conformation influence electron transport in both saturated and pi-conjugated nanowires. However, there is relatively little experimental data on electron transport through fused aromatic rings. Here we show using diaminoacenes that conductivity depends not only on the number of fused aromatic rings in the molecule, which defines the molecular HOMO-LUMO gap, but also on the position of the amino groups on the rings. Specifically, we find that conductance is highest with minimal disruption of aromaticity in fused aromatic nanowires.Comment: 2 pages, 3 figure

Local Theory of Almost Split Sequences for Comodules

We show that almost split sequences in the category of comodules over a coalgebra with finite-dimensional right-hand term are direct limits of almost split sequences over finite dimensional subcoalgebras. In previous work we showed that such almost split sequences exist if the right hand term has a quasifinitely copresented linear dual. Conversely, taking limits of almost split sequences over finte-dimensional comodule categories, we then show that, for countable-dimensional coalgebras, certain exact sequences exist which satisfy a condition weaker than being almost split, which we call ``finitely almost split\u27\u27. Under additional assumptions, these sequences are shown to be almost split in the appropriate category