Indexing the Event Calculus with Kd-trees to Monitor Diabetes

Personal Health Systems (PHS) are mobile solutions tailored to monitoring patients affected by chronic non communicable diseases. A patient affected by a chronic disease can generate large amounts of events. Type 1 Diabetic patients generate several glucose events per day, ranging from at least 6 events per day (under normal monitoring) to 288 per day when wearing a continuous glucose monitor (CGM) that samples the blood every 5 minutes for several days. This is a large number of events to monitor for medical doctors, in particular when considering that they may have to take decisions concerning adjusting the treatment, which may impact the life of the patients for a long time. Given the need to analyse such a large stream of data, doctors need a simple approach towards physiological time series that allows them to promptly transfer their knowledge into queries to identify interesting patterns in the data. Achieving this with current technology is not an easy task, as on one hand it cannot be expected that medical doctors have the technical knowledge to query databases and on the other hand these time series include thousands of events, which requires to re-think the way data is indexed. In order to tackle the knowledge representation and efficiency problem, this contribution presents the kd-tree cached event calculus (\ceckd) an event calculus extension for knowledge engineering of temporal rules capable to handle many thousands events produced by a diabetic patient. \ceckd\ is built as a support to a graphical interface to represent monitoring rules for diabetes type 1. In addition, the paper evaluates the \ceckd\ with respect to the cached event calculus (CEC) to show how indexing events using kd-trees improves scalability with respect to the current state of the art.Comment: 24 pages, preliminary results calculated on an implementation of CECKD, precursor to Journal paper being submitted in 2017, with further indexing and results possibilities, put here for reference and chronological purposes to remember how the idea evolve

Risk analysis for RoPax vessels

The paper presents the results of a recent risk analysis study for RoPax vessels, carried out as part of the activities of the SAFEDOR Integrated Project. The objective of this study was to investigate the causes of hazards during RoPax operation and quantify, to the extent possible, their frequencies and consequences. Potential scenarios initially identified and prioritised during a Hazard Identification (HAZID) session were used in the pro cess. The work has been performed in accordance with the IMO FSA Guidelines (IMO 2002). A previous comprehensive study on the safety assessment of RoPax vessels sailing in North West European waters, covering the period until 1994, was used as the basis in putting together a high-level risk model for the current study. All scenarios are presented in the form of event trees, quantification of which is done on the basis of world-wide accident experience (from 1994 to 2004), relevant past studies and judgment. The study estimates the risk of loss of life among passengers and crew (by calculating for each scenario the In di -vidual Risk, the Potential Loss of Life – PLL and plotting the corresponding F-N curves), and compares them with current risk acceptance criteria. The resulting high-level risk model is used to provide recommendations for improvement in the form of proposed risk control options (RCOs)

Risk evaluation for RoPax vessels

The paper presents the results of a recent risk evalua-tion study for RoPax vessels, carried out as part of the activities of the SAFEDOR Integrated Project. The objective of the study was to investigate hazards and their causes during RoPax operation and to quantify, to the extent possible, their frequencies and conse-quences. A previous study on the safety assessment of RoPax vessels sailing in North-West European waters, covering the period until 1994, was used as the basis in putting together a high-level risk model for the current study. All scenarios are presented in the form of event trees, quantification of which is done on the basis of world-wide accident experience (from 1994 to 2004), relevant past studies and judgment. The study esti-mates the risk of loss of life among passengers and crew (by calculating for each scenario the Individual Risk, the Potential Loss of Life – PLL and plotting the corresponding F-N curves), and compares them with current risk acceptance criteria

Exact Failure Frequency Calculations for Extended Systems

This paper shows how the steady-state availability and failure frequency can be calculated in a single pass for very large systems, when the availability is expressed as a product of matrices. We apply the general procedure to $k$-out-of-$n$:G and linear consecutive $k$-out-of-$n$:F systems, and to a simple ladder network in which each edge and node may fail. We also give the associated generating functions when the components have identical availabilities and failure rates. For large systems, the failure rate of the whole system is asymptotically proportional to its size. This paves the way to ready-to-use formulae for various architectures, as well as proof that the differential operator approach to failure frequency calculations is very useful and straightforward

Composite load spectra for select space propulsion structural components

The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen posts and system ducting. The first approach will consist of using state of the art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The second approach will consist of developing coupled models for composite load spectra simulation which combine the deterministic models for composite load dynamic, acoustic, high pressure, and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data