Modeling and Optimizing Patient Flows

constructing a consistent process model and its simulation can be instrumental to be used in healthcare issues such as Consistent patient flow modeling. Current process modeling techniques used in healthcare are intuitive and imprecise such as flowcharts, unified modeling language activity diagram (UML AD) and business process modeling notation (BPMN). These techniques are vague in process description and cannot fully capture the complexities of the types of activities and types of temporal constraints between them. Additionally, to schedule patient flows; current modeling techniques does not offer any mechanism so healthcare relies on critical path method(CPM) and program evaluation review technique (PERT) that also have limitations i.e. finish-start barrier. It is imperative that temporal constraints between the start and/or end of a process needs to be specified, e.g., the start of A precedes the start (or end) of B, etc., however, these approaches failed to provide us with a mechanism for handling these temporal situations. This paper proposes a framework that provides enumeration of core concepts to describe a general knowledge base for Business and Healthcare domains. Algorithms are provided to represent the semantics of concepts i.e. based on their ontology. Furthermore, this logical basis is supported by Point graph (PG); a graphical tool, which has a formal translation to a point interval temporal logic (PITL) is used to simulate Patient flows for enhanced reasoning and correct representation. We will briefly evaluate an illustrative discharge patient flow example initially modeled using Unified Modeling Language Activity Diagram (UML AD) with the intention to compare with the technique presented here for its potential use to model patient flows

Modeling Patient Flows: A Temporal Logic Approach

Constructing a consistent process model can be instrumental in streamlining healthcare issues. Current process modeling techniques used in healthcare, such as flowcharts, unified modeling language activity diagram (UML AD), and business process modeling notation (BPMN) are intuitive and imprecise. These techniques are vague in process description and cannot fully capture the complexities of the types of activities and full extent of temporal constraints between them. Additionally, to schedule patient flows, current modeling techniques do not offer any mechanism, so healthcare relies on critical path method (CPM) and program evaluation review technique (PERT), that also have limitations i.e. finish-start barrier. It is imperative that temporal constraints between the start and/or end of a process needs to be specified, e.g., the start of A precedes the start (or end) of B, etc., however, these approaches failed to provide us with a mechanism for handling these temporal situations. This paper proposes a framework that provides enumeration of core terms/concepts to describe a general knowledge basis for Business and Healthcare domains. Definitions are provided to present the semantics of concepts i.e. based on their ontology. Furthermore, this logical basis is supported by Point graph (PG) notation; a graphical tool, which has a formal translation to a point interval temporal logic (PITL), and is used to model Patient flows suitable for enhanced reasoning and correct representation. We will evaluate an illustrative discharge patient flow example initially modeled using Unified Modeling Language Activity Diagram (UML AD) with the intention to compare with the technique presented here for its potential use to model patient flows

Numerical analysis of damage progression and strength of countersunk composite joints

A numerical investigation is conducted into the damage progression and strength of bolted joints between fibre-reinforced composite laminates using countersunk fasteners. Experimental tests were previously conducted on a bearing test specimen and countersunk fastener single-lap joints. In this work, computational models are developed for Abaqus/Explicit, with continuum shells employed to model in-plane ply failure. The bolt-nut assembly is modelled with rigid elements, and the models account for bolt torque and frictional contact. The material properties required in the computational model are determined from standard tests, with the compression fracture toughness of composite plies calibrated against experimental data from the bearing test. The analysis approach captures the load-carrying capability of all configurations, and provides reasonable accuracy in predicting damage patterns. The effects of bolt torque, clearance and countersink height ratio are investigated, and the analysis results compare well with experimental findings. Furthermore, the analysis provides rich insight into the damage progression and joint behaviour at the ply level, with the in-plane and through-thickness damage patterns mapped for increasing applied load. Delamination is incorporated using a cohesive element layer at the start of the countersunk region, though has minimal influence on damage progression and load-carrying capability, which agrees with the experimental results

Characterising fibre compression fracture toughness of composites using bearing tests

In this paper we propose the use of a bearing test with a coupled experimental-numerical approach to characterise the critical strain energy release rate, or "fracture toughness", for fibre compression failure in bearing

Experimental investigation of damage progression and strength of countersunk composite joints

An experimental investigation is conducted into the damage progression and strength of bolted joints with fibre-reinforced composite laminates and countersunk fasteners. The main goal of the experimental investigation is to characterise the effect of the countersink geometry on the load-carrying capacity of single lap joints in comparison to the straight-shank case. The effects of bolt torque, clearance and countersink height ratio on the damage progression and joint strength are also studied. Experimental tests and detailed microscopy studies are conducted on a bearing test specimen with a straight-edged hole, and several single-lap joint configurations with countersunk fasteners. It is found that introduction of the countersunk hole roughly halves the bearing stress, and causes delamination for some configurations. This delamination is primarily located at the start of the countersink region, though is found to be triggered by other damage mechanisms and has only minor influence on the results. Bolt torque increases the density of through-thickness damage though limits its extension from the hole edge, whilst bolt clearance causes localisation of the damage region. Increasing the ratio of the countersink depth to the laminate thickness reduces the extent of bearing and promotes bending, with a change to net section failure at large ratios

The effect of clearance on single lap countersunk composite joints

An experimental investigation was conducted into the effects of bolt-hole clearance on the static strength and damage progression behaviour of single lap countersunk composite bolted joints. Joints were manufactured from carbon/epoxy plain weave fabric and tested with three different bolt clearance levels. The experimental results showed that the bolt-hole clearance had a minimal effect on the ultimate failure load of the bolted joint. However, a significant reduction (approx. 22%) was observed in the bearing damage initiation load, consistent with difference in the through-thickness damage profile. Finite element analysis was conducted, and was able to accurately capture the load-displacement behaviour and through-thickness damage profile of the joints

On vertex independence number of uniform hypergraphs

Abstract Let H be an r-uniform hypergraph with r ≥ 2 and let α(H) be its vertex independence number. In the paper bounds of α(H) are given for different uniform hypergraphs: if H has no isolated vertex, then in terms of the degrees, and for triangle-free linear H in terms of the order and average degree.</jats:p