title: Using state machines for the visualisation of specifications via refinement

authors: Pilbrow, Colin

abstract: We talk in this paper about using state machines and refinement to characterise the visualisation of a computation.

We use Z specifications to give examples of systems in the usual way, and then use Z schemas to also represent states and transitions in state machines, which we consider to be a particular kind of visualisation of a specified system.

We have investigated the principle of substitutivity and the idea of downward simulation to check whether or not a refinement relation exists between the specification and the state machine. We are looking at this because we believe that the soundness of the visualisation can be captured by such a refinement relationship.

text: Using state machines for the visualisation of specifications via refinement We talk in this paper about using state machines and refinement to characterise the visualisation of a computation.

We use Z specifications to give examples of systems in the usual way, and then use Z schemas to also represent states and transitions in state machines, which we consider to be a particular kind of visualisation of a specified system.

We have investigated the principle of substitutivity and the idea of downward simulation to check whether or not a refinement relation exists between the specification and the state machine. We are looking at this because we believe that the soundness of the visualisation can be captured by such a refinement relationship.

year: 2015

title: The architecture of an optimistic CPU: the WarpEngine

authors: Cleary, John G.

subjects: computer science

abstract: The architecture for a shared memory CPU is described. The CPU allows for parallelism down to the level of single instructions and is tolerant of memory latency. All executable instructions and memory accesses are time stamped. The TimeWarp algorithm is used for managing synchronisation. This algorithm is optimistic and requires that all computations can be rolled back. The basic functions required for implementing the control and memory system used by TimeWarp are described. The memory model presented to the programmer is a single linear address space modified by a single thread of control. Thus, at the software level there is no need for explicit synchronising actions when accessing memory. The physical implementation, however, is multiple CPUs with their own caches and local memory with each CPU simultaneously executing multiple threads of control.

text: The architecture of an optimistic CPU: the WarpEngine The architecture for a shared memory CPU is described. The CPU allows for parallelism down to the level of single instructions and is tolerant of memory latency. All executable instructions and memory accesses are time stamped. The TimeWarp algorithm is used for managing synchronisation. This algorithm is optimistic and requires that all computations can be rolled back. The basic functions required for implementing the control and memory system used by TimeWarp are described. The memory model presented to the programmer is a single linear address space modified by a single thread of control. Thus, at the software level there is no need for explicit synchronising actions when accessing memory. The physical implementation, however, is multiple CPUs with their own caches and local memory with each CPU simultaneously executing multiple threads of control.

year: 1994-09

title: Real world initiation of newly funded empagliflozin and dulaglutide under special authority for patients with type 2 diabetes in New Zealand

authors: Chepulis, Lynne Merran

subjects: GLP1RA

abstract: Background: Type 2 diabetes (T2D) is sub-optimally managed for many in Aotearoa New Zealand, and disproportionately affects Māori and Pacific peoples. In February 2021, SGLT2i/GLP1RA agents were funded for use for the first time with prioritisation for Māori, Pacific and those with cardiovascular and/or renal disease or risk (CVRD). This study evaluates the impact of health system factors on initiation of SGLT2i/GLP1RA therapy. 

Methods: Primary care data was collected for patients with T2D aged 18–75 years from four primary care organisations (302 general practices) in the Auckland / Waikato region of New Zealand (Feb 2021 – July 2022). Initiation of SGLT2i/GLP1RA therapy was reviewed by patient (age, gender, ethnicity, CVRD status) and health system variables (funding, provider type, staffing, patient numbers, rurality, after-hours access). Logistic regression was used to estimate the odds ratio of a patient being dispensed SGLT2i/GLP1RA. 

Results: Of 57,743 patients with T2D, 22,331 were eligible for funded SGLT2i/GLP1RA access and 10,272 of those (46.0%) were prescribed. Initiation of therapy was highest in Māori (50.8%) and Pacific (48.8%) patients (vs. 36·2–40·7% of other ethnic groups; P < 0.001), but was comparable in those with and without CVRD (47·1% vs. 48·9%; P = 0.2). Prescribing was highest in practices with higher doctor/patient numbers, low-cost fees, Māori health providers and clinics without after-hours access.

Conclusion: Prioritised access for SGLT2i/GLP1RA appears to be associated with a reduced health equity gap for Māori and Pacific patients with T2D in NZ, but work is required to improve prescribing for patients with CVRD.

text: Real world initiation of newly funded empagliflozin and dulaglutide under special authority for patients with type 2 diabetes in New Zealand Background: Type 2 diabetes (T2D) is sub-optimally managed for many in Aotearoa New Zealand, and disproportionately affects Māori and Pacific peoples. In February 2021, SGLT2i/GLP1RA agents were funded for use for the first time with prioritisation for Māori, Pacific and those with cardiovascular and/or renal disease or risk (CVRD). This study evaluates the impact of health system factors on initiation of SGLT2i/GLP1RA therapy. 

Methods: Primary care data was collected for patients with T2D aged 18–75 years from four primary care organisations (302 general practices) in the Auckland / Waikato region of New Zealand (Feb 2021 – July 2022). Initiation of SGLT2i/GLP1RA therapy was reviewed by patient (age, gender, ethnicity, CVRD status) and health system variables (funding, provider type, staffing, patient numbers, rurality, after-hours access). Logistic regression was used to estimate the odds ratio of a patient being dispensed SGLT2i/GLP1RA. 

Results: Of 57,743 patients with T2D, 22,331 were eligible for funded SGLT2i/GLP1RA access and 10,272 of those (46.0%) were prescribed. Initiation of therapy was highest in Māori (50.8%) and Pacific (48.8%) patients (vs. 36·2–40·7% of other ethnic groups; P < 0.001), but was comparable in those with and without CVRD (47·1% vs. 48·9%; P = 0.2). Prescribing was highest in practices with higher doctor/patient numbers, low-cost fees, Māori health providers and clinics without after-hours access.

Conclusion: Prioritised access for SGLT2i/GLP1RA appears to be associated with a reduced health equity gap for Māori and Pacific patients with T2D in NZ, but work is required to improve prescribing for patients with CVRD.

year: 2025