On the rotating surge and stall and the polar control method

In this paper, the polar controller is applied to the three-state, one-mode Moore-Greitzer Compressor model. A benchmark is first established with a backstepping controller. The polar control method is then explained, and compared to the backstepping controller. The polar controller is used successfully to control the surge and stall problem in the presence of both disturbances and uncertainties

Approximate string matching with reduced alphabet

Peer reviewe

Increasing follow-up questionnaire response rates in a randomized controlled trial of telehealth for depression: three embedded controlled studies

Background: Attrition is problematic in trials, and may be exacerbated in longer studies, telehealth trials and participants with depression – three features of The Healthlines Study. Advance notification, including a photograph and using action-oriented email subject lines might increase response rates, but require further investigation. We examined the effectiveness of these interventions in three embedded Healthlines studies. Methods: Based in different trial sites, participants with depression were alternately allocated to be pre-called or not ahead of the 8-month follow-up questionnaire (Study 1), randomized to receive a research team photograph or not with their 12-month questionnaire (Study 2), and randomized to receive an action-oriented (‘ACTION REQUIRED’) or standard (‘Questionnaire reminder’) 12-month email reminder (Study 3). Participants could complete online or postal questionnaires, and received up to five questionnaire reminders. The primary outcome was completion of the Patient Health Questionnaire (PHQ-9). Secondary outcome measures were the number of reminders and time to questionnaire completion. Results: Of a total of 609 Healthlines depression participants, 190, 251 and 231 participants were included in Studies 1–3 (intervention: 95, 126 and 115), respectively. Outcome completion was ≥90 % across studies, with no differences between trial arms (Study 1: OR 0.38, 95 % CI 0.07–2.10; Study 2: OR 0.84, 95 % CI 0.26–2.66; Study 3: OR 0.53 95 % CI 0.19–1.49). Pre-called participants were less likely to require a reminder (48.4 % vs 62.1 %, OR 0.41, 95 % CI 0.21–0.78), required fewer reminders (adjusted difference in means −0.67, 95 % CI −1.13 to −0.20), and completed follow-up quicker (median 8 vs 15 days, HR 1.35, 95 % CI 1.00–1.82) than control subjects. There were no significant between-group differences in Studies 2 or 3. Conclusions: Eventual response rates in this trial were high, with no further improvement from these interventions. While the photograph and email interventions were ineffective, pre-calling participants reduced time to completion. This strategy might be helpful when the timing of study completion is important. Researchers perceived a substantial benefit from the reduction in reminders with pre-calling, despite no overall decrease in net effort after accounting for pre-notification

A Symmetric Approach to Compilation and Decompilation

Just as specializing a source interpreter can achieve compilation from a source language to a target language, we observe that specializing a target interpreter can achieve compilation from the target language to the source language. In both cases, the key issue is the choice of whether to perform an evaluation or to emit code that represents this evaluation. We substantiate this observation by specializing two source interpreters and two target interpreters. We first consider a source language of arithmetic expressions and a target language for a stack machine, and then the lambda-calculus and the SECD-machine language. In each case, we prove that the target-to-source compiler is a left inverse of the source-to-target compiler, i.e., it is a decompiler. In the context of partial evaluation, compilation by source-interpreter specialization is classically referred to as a Futamura projection. By symmetry, it seems logical to refer to decompilation by target-interpreter specialization as a Futamura embedding

Landslides Triggered by the MW 7.8 14 November 2016 Kaikoura Earthquake, New Zealand

The MW 7.8 14 November 2016 Kaikoura earthquake generated more than 10000 landslides over a total area of about 10000 km2, with the majority concentrated in a smaller area of about 3600 km2. The largest landslide triggered by the earthquake had an approximate volume of 20 (±2) M m3, with a runout distance of about 2.7 km, forming a dam on the Hapuku River. In this paper, we present version 1.0 of the landslide inventory we have created for this event. We use the inventory presented in this paper to identify and discuss some of the controls on the spatial distribution of landslides triggered by the Kaikoura earthquake. Our main findings are (1) the number of medium to large landslides (source area ≥10000 m2) triggered by the Kaikoura earthquake is smaller than for similar sized landslides triggered by similar magnitude earthquakes in New Zealand; (2) seven of the largest eight landslides (from 5 to 20 x 106 m3) occurred on faults that ruptured to the surface during the earthquake; (3) the average landslide density within 200 m of a mapped surface fault rupture is three times that at a distance of 2500 m or more from a mapped surface fault rupture ; (4) the “distance to fault” predictor variable, when used as a proxy for ground-motion intensity, and when combined with slope angle, geology and elevation variables, has more power in predicting landslide probability than the modelled peak ground acceleration or peak ground velocity; and (5) for the same slope angles, the coastal slopes have landslide point densities that are an order of magnitude greater than those in similar materials on the inland slopes, but their source areas are significantly smaller

On the rotating surge and stall and the polar control method

In this paper, the polar controller is applied to the three-state, one-mode Moore-Greitzer Compressor model. A benchmark is first established with a backstepping controller. The polar control method is then explained, and compared to the backstepping controller. The polar controller is used successfully to control the surge and stall problem in the presence of both disturbances and uncertainties.IEE

Associations between neighbourhood environmental factors and the uptake and effectiveness of a brief intervention to increase physical activity: findings from deprived urban communities in an English city

Background: Evidence suggests behavioural interventions may exacerbate health inequalities, potentially due to differences in uptake or effectiveness. We used a physical activity intervention targeting deprived communities to identify neighbourhood-level factors that might explain differences in programme impact. Methods: Individuals aged 40–65 were sent a postal invitation offering a brief intervention to increase physical activity. We used postcodes linkage to determine whether neighbourhood indicators of deprivation, housing, crime and proximity to green spaces and leisure facilities predicted uptake of the initial invitation or an increase in physical activity level in those receiving the brief intervention. Results: A total of 4134 (6.8%) individuals responded to the initial invitation and of those receiving the intervention and contactable after 3 months, 486 (51.6%) reported an increase in physical activity. Area deprivation scores linked to postcodes predicted intervention uptake, but not intervention effectiveness. Neighbourhood indicators did not predict either uptake or intervention effectiveness. Conclusions: The main barrier to using brief intervention invitations to increase physical activity in deprived, middle-aged populations was the low uptake of an intervention requiring significant time and motivation from participants. Once individuals have taken up the intervention offer, neighbourhood characteristics did not appear to be significant barriers to successful lifestyle change

Succinct Suffix Arrays based on Run-Length Encoding

Mäkinen V, Navarro G. Succinct Suffix Arrays based on Run-Length Encoding. In: Apostolico A, ed. Proc. 16th Annual Symposium on Combinatorial Pattern Matching (CPM 2005). Lecture notes in computer science. Vol 3537. Berlin, Heidelberg: Springer Berlin Heidelberg; 2005: 45-56