Code Generation in the Programmer's Apprentice

The Programmer's Apprentice is a highly interactive program development tool. The user interface to the system relies on program text which is generated from an internal plan representation. The programs generated need to be easy for a programmer to read and understand. This paper describes a design for a code generation module which can be tailored to produce code which reflects the stylistic preferences of individual programmers.MIT Artificial Intelligence Laborator

Why are patients with diabetic peripheral neuropathy more likely to fall? An examination of the underpinning biomechanical mechanisms of locomotion and the influence of intervention.

The research for this thesis examined the effects of diabetic peripheral neuropathy (DPN) on biomechanical factors related to the risk of falling during locomotor tasks, and the effects of a 16-week multi-factorial intervention on the identified impairments. The speed of ankle and knee strength generation, and muscular activations were measured during stair ascent and descent; and minimum toe clearance, stepping accuracy, and visual gaze parameters were measured during level ground walking. Patients with DPN, diabetes patients with no neuropathy and non-diabetic controls were measured before and after a 16-week intervention consisting of high-load resistance exercises and a visual gaze training task. Patients with DPN displayed slower ankle and knee strength generation during stair ascent and descent than healthy controls (p<0.05). Post-intervention, strength was generated faster at the ankle and knee during both tasks (p<0.05), which is expected to improve stability during the weight acceptance phase. During level ground walking, patients with DPN displayed a higher minimum toe clearance (p<0.05), which is expected to reduce the risk of tripping on smaller, less observable hazards; but displayed a decreased stepping accuracy (p<0.05), which may reduce the ability to avoid tripping hazards. Stepping accuracy was improved as a result of the intervention (p<0.05), which may originate from improvements in visual gaze strategy and motor control, contributing to reduce the risk of tripping in patients with DPN. Biomechanical impairments during locomotion were observed in patients with DPN; however, the intervention improved these aspects and may reduce the risk of falling in this population

Altered joint moment strategy during stair walking in diabetes patients with and without peripheral neuropathy

© 2016 The Authors. Aim: To investigate lower limb biomechanical strategy during stair walking in patients with diabetes and patients with diabetic peripheral neuropathy, a population known to exhibit lower limb muscular weakness. Methods: The peak lower limb joint moments of twenty-two patients with diabetic peripheral neuropathy and thirty-nine patients with diabetes and no neuropathy were compared during ascent and descent of a staircase to thirty-two healthy controls. Fifty-nine of the ninety-four participants also performed assessment of their maximum isokinetic ankle and knee joint moment (muscle strength) to assess the level of peak joint moments during the stair task relative to their maximal joint moment-generating capabilities (operating strengths). Results: Both patient groups ascended and descended stairs slower than controls (p < 0.05). Peak joint moments in patients with diabetic peripheral neuropathy were lower (p < 0.05) at the ankle and knee during stair ascent, and knee only during stair descent compared to controls. Ankle and knee muscle strength values were lower (p < 0.05) in patients with diabetic peripheral neuropathy compared to controls, and lower at knee only in patients without neuropathy. Operating strengths were higher (p < 0.05) at the ankle and knee in patients with neuropathy during stair descent compared to the controls, but not during stair ascent. Conclusion: Patients with diabetic peripheral neuropathy walk slower to alter gait strategy during stair walking and account for lower-limb muscular weakness, but still exhibit heightened operating strengths during stair descent, which may impact upon fatigue and the ability to recover a safe stance following postural instability

CFD prediction of performance of wind turbines integrated in the existing civil infrastructure

Power generation from wind energy is almost entirely performed in rural locations or at sea, and very little attention has been given to the use of wind turbines in urban locations. Since the re-emergence of wind turbines, the majority of their applications are in large commercial wind farms in rural areas or out at sea, and there is an increasing focus on the use of wind turbines within an urban environment possibly using existing structures, such as bridges and viaducts. There are very few existing buildings which have been designed from the ground-up to include wind turbines in the structure. In order to estimate the wind resources and the performance of a turbine at a particular site, a CFD model is designed and CFD calculations are performed. In order to simplify the modelling of a wind turbine actuator, disc theory is applied. Actuator disc theory is used, as it allows the aerodynamic behaviour of a wind turbine to be analyzed by just considering the energy extraction process without a specific wind turbine design. The power output of wind turbines installed beneath an already existing civil infrastructure is determined and analyzed

THE RELATIONSHIP OF ANTHROPOMETRY AND BODY COMPOSITION WITH RUNNING ECONOMY

The aim of this study was to investigate the relationships of anthropometry and body composition with running economy within a large heterogeneous cohort of runners. Locomotory energy cost was determined in ninety-four healthy male and female endurance runners across a range of performance standards. Various anthropometric and body composition measurements were taken manually and via DXA scans. The relationships between anthropometry and running economy were assessed using independent Pearson’s correlation and stepwise multiple linear regression. Three parameters, normalised neck and calf perimeters and normalised whole body bone mass explained 30% of the variance in locomotory energy cost. Low locomotory energy cost was related solely to parameters indicating relative slenderness of the body

A kinematic algorithm to identify gait events during running at different speeds and with different footstrike types

Although a number of algorithms exist for estimating ground contact events (GCEs) from kinematic data during running, they are typically only applicable to heelstrike running, or have only been evaluated at a single running speed. The purpose of this study was to investigate the accuracy of four kinematics-based algorithms to estimate GCEs over a range of running speeds and footstrike types. Subjects ran over a force platform at a range of speeds; kinetic and kinematic data was captured at 1000 Hz, and kinematic data was downsampled to 250 Hz. A windowing process initially identified reduced time windows containing touchdown and toe-off. Algorithms based on acceleration and jerk signals of the foot markers were used to estimate touchdown (2 algorithms), toe-off (2 algorithms), and ground contact time (GCT) (4 algorithms), and compared to synchronous ‘gold standard’ force platform data. An algorithm utilising the vertical acceleration peak of either the heel or first metatarsal marker (whichever appeared first) for touchdown, and the vertical jerk peak of the hallux marker for toe-off, resulted in the lowest offsets (+3.1 ms, 95% Confidence Interval (CI): -11.8 to +18.1 ms; and +2.1 ms, CI: -8.1 to +12.2 ms respectively). This method also resulted in the smallest offset in GCT (-1.1 ms, CI: -18.6 to +16.4 ms). Offsets in GCE and GCT estimates from all algorithms were typically negatively correlated to running speed, with offsets decreasing as speed increased. Assessing GCEs and GCT using this method may be useful when a force platform is unavailable or impractical

Running technique is an important component of running economy and performance

© 2017 American College of Sports MedicineDespite an intuitive relationship between technique and both running economy (RE) and performance, and the diverse techniques employed by runners to achieve forward locomotion, the objective importance of overall technique and the key components therein remain to be elucidated. PURPOSE: To determine the relationship between individual and combined kinematic measures of technique with both RE and performance. METHODS: Ninety-seven endurance runners (47 female) of diverse competitive standards performed a discontinuous protocol of incremental treadmill running (4 min stages, 1 km.h increments). Measurements included three-dimensional full body kinematics, respiratory gases to determine energy cost, and velocity of lactate turnpoint (vLTP). Five categories of kinematic measures (vertical oscillation, braking, posture, stride parameters and lower limb angles) and locomotory energy cost (LEc) were averaged across 10-12 km.h (the highest common velocit

Is there an optimum speed for economical running?

The influence of running speed and sex on running economy is unclear and may have been confounded by measurements of oxygen cost that do not account for known differences in substrate metabolism, across a limited range of speeds, and differences in performance standard. Therefore, this study assessed the energy cost of running over a wide range of speeds in high-level and recreational runners to investigate the effect of speed (considered in absolute and relative terms) and sex (males vs. females of equivalent performance standard) on running economy. 92 healthy runners (high-level males, n=14; high-level females, n=10; recreational males, n=35; recreational females, n=33) completed a discontinuous incremental treadmill test for the determination of the energy cost (kcal·kg 1·km-1) of submaximal running, speed at lactate turnpoint (sLTP) and the maximal rate of oxygen uptake (V̇O2max). There were no sex specific differences in the energy cost of running for the recreational or high-level runners when compared at absolute or relative running speeds (P>0.05). The absolute and relative speed-energy cost relationships for the high-level runners demonstrated a curvilinear inverted “u shape” with a nadir reflecting the most economical speed at 13 km.h-1 or 70% sLTP. The high-level runners were more economical than the recreational runners at all absolute and relative running speeds (P<0.05). These findings demonstrate that there is an optimal speed for economical running; there is no sex-specific difference; and, high-level endurance runners exhibit a better running economy than recreational endurance runners