Mark Pickering

Prof. Mark Pickering


Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
21 April 2016 in International Journal of Behavioral Nutrition and Physical Activity
Verified
Journal Article
Open access
PDF file
DKDeborah Kerr
Deborah Kerr
Amelia HarrayAmelia Harray
Amelia Harray
Christina Mary PollardChristina Mary Pollard
Christina Mary Pollard
SDSatvinder Dhaliwal
Satvinder Dhaliwal
EDEdward Delp
Edward Delp
CBCarol Boushey
Carol Boushey
Early adulthood represents the transition to independent living which is a period when changes in diet and body weight are likely to occur. This presents an ideal time for health interventions to reduce the effect of health problems and risk factors for chronic disease in later life. As young adults are high users of mobile devices, interventions that use this technology may improve engagement. The Connecting Health and Technology study aimed to evaluate the effectiveness of tailored dietary feedback and weekly text messaging to improve dietary intake of fruit, vegetables and junk food over 6 months among a population-based sample of men and women (aged 18–30 years). A three-arm, parallel, randomized control trial was conducted. After baseline assessments, participants were randomized to one of three groups: A) dietary feedback and weekly text messages, B) dietary feedback only or C) control group. Dietary intake was assessed using a mobile food record App (mFR) where participants captured images of foods and beverages consumed over 4-days at baseline and post-intervention. The primary outcomes were changes in serves of fruits, vegetables, energy-dense nutrient-poor (EDNP) foods and sugar-sweetened beverages (SSB). The intervention effects were assessed using linear mixed effect models for change in food group serves. Young adults (n = 247) were randomized to group A (n = 82), group B (n = 83), or group C (n = 82). Overall, no changes in food group serves for either intervention groups were observed. An unanticipated outcome was a mean weight reduction of 1.7 kg (P = .02) among the dietary feedback only. Men who received dietary feedback only, significantly reduced their serves of EDNP foods by a mean of 1.4 serves/day (P = .02). Women who received dietary feedback only significantly reduced their intake of SSB (P = .04) by an average of 0.2 serves/day compared with controls. Tailored dietary feedback only resulted in a decrease in EDNP foods in men and SSB in women, together with a reduction in body weight. Using a mobile food record for dietary assessment and tailored feedback has great potential for future health promotion interventions targeting diet and weight in young adults. Australian Clinical Trials Registry Registration number: ACTRN12612000250831 .

26 August 2016 in IEEE Transactions on Image Processing
Verified
Journal Article
Closed access
GWGengkun Wang
Gengkun Wang
Wei XiangWei Xiang
Wei Xiang
MPMark Pickering
Mark Pickering
CCChang Wen Chen
Chang Wen Chen
Light field (LF) technology has been popularly adopted by a wide range of conventional industries. However, one problem when dealing with LFs is the sheer size of data volume. There have been many multi-view video coding (MVC)-based LF video coding methods reported in the literature, aiming at finding the best prediction structure for LF video coding. It is clear that the number of possible prediction structures is unlimited, and it is also observed that the coding bit-rate can be reduced by increasing the number of bi-directionally encoded views in the prediction structure. However, none work has been conducted to analyze the relationship of the prediction structure with its coding performance. In light of this observation, we first design a new LF-MVC prediction structure by extending the inter-view prediction into a two-directional parallel structure. Analytical models for source coding rate and encoding time are developed to analyze their relationships with the prediction structure, and are proven to be well-matched to our experimental results. Experimental evaluation of two LF video sequences demonstrates that the proposed LF-MVC prediction structure can achieve a factor of 26% bit-rate reduction against the conventional MVC prediction structure for an LF video with 5 × 5 views, and a further 34% bit-rate reduction for an LF video with a larger 10 × 10 views. Compared with the state-of-the-art MVC-based LF video coding prediction structures in the literature, LF-MVC can achieve the best coding performance, and with its high encoding efficiency, is well suited for deployment in practical LF-based 3D systems.

22 June 2012 in BMC Public Health
Verified
Journal Article
Open access
PDF file
DKDeborah Kerr
Deborah Kerr
Christina Mary PollardChristina Mary Pollard
Christina Mary Pollard
PHPeter Howat
Peter Howat
EDEdward Delp
Edward Delp
MPMark Pickering
Mark Pickering
CBCarol Boushey
Carol Boushey
Increasing intakes of fruits and vegetables intake, in tandem with reducing consumption of energy-dense and nutrient poor foods and beverages are dietary priorities to prevent chronic disease. Although most adults do not eat enough fruit and vegetables, teenagers and young adults tend to have the lowest intakes. Young adults typically consume a diet which is inconsistent with the dietary recommendations. Yet little is known about the best approaches to improve dietary intakes and behaviours among this group. This randomised controlled trial aims to evaluate the effectiveness of using a mobile device to assess dietary intake, provide tailored dietary feedback and text messages to motivate changes in fruit, vegetable and junk food consumption among young adults.

15 March 2010 in IEEE Transactions on Circuits and Systems for Video Technology
Verified
Journal Article
Closed access
AMAbdullah A. Muhit
Abdullah A. Muhit
MPMark Pickering
Mark Pickering
MFMichael R. Frater
Michael R. Frater
JAJohn F. Arnold
John F. Arnold
Motion-compensated prediction is the key to high-performance video coding. Previous works have explored alternatives to the classical translational motion model in video coding, but the cumulative rate-distortion performance has not been significant enough to see such approaches adopted in mainstream standards. In this paper, we propose a new extended prediction strategy that incorporates non-translational motion prediction. This method uses an elastic motion model with 2-D cosine basis functions to estimate non-translational motion between the blocks. To achieve superior performance, the proposed scheme takes advantage of larger blocks with multi-level partitioning. Experimental results show that this combined framework outperforms the existing techniques, including those available in the recent H.264 standard.

12 November 2015 in BMC Musculoskeletal Disorders
Verified
Journal Article
Open access
PDF file
BSBenjamin G Serpell
Benjamin G Serpell
JSJennie M. Scarvell
Jennie M. Scarvell
MPMark Pickering
Mark Pickering
NBNick Ball
Nick Ball
PNPhil Newman
Phil Newman
PSPaul Smith
Paul Smith
Many injury prevention and rehabilitation programs aim to train hamstring and quadriceps co-activation to constrain excessive anterior tibial translation and protect the anterior cruciate ligament (ACL) from injury. However, despite strong clinical belief in its efficacy, primary evidence supporting training co-activation of the hamstrings and quadriceps muscles for ACL injury prevention and rehabilitation is quite limited. Therefore, the purpose of the study presented in this paper was to determine if hamstring-quadriceps co-activation alters knee joint kinematics, and also establish if it affects ACL elongation. A computed tomography (CT) scan from each participant’s dominant leg was acquired prior to performing two step-ups under fluoroscopy: one with ‘natural’ hamstring-quadriceps co-activation, one with deliberate co-activation. Electromyography was used to confirm increased motor unit recruitment. The CT scan was registered to fluoroscopy for 4-D modeling, and knee joint kinematics subsequently measured. Anterior cruciate ligament attachments were mapped to the 4-D models and its length was assumed from the distance between attachments. Anterior cruciate ligament elongation was derived from the change in distance between those points as they moved relative to each other. Reduced ACL elongation as well as knee joint rotation, abduction, translation, and distraction was observed for the step up with increased co-activation. A relationship was shown to exist for change in ACL length with knee abduction (r = 0.91; p ≤ 0.001), with distraction (r = −0.70; p = 0.02 for relationship with compression), and with anterior tibial translation (r = 0.52; p = 0.01). However, ACL elongation was not associated with internal rotation or medial translation. Medial hamstring-quadriceps co-activation was associated with a shorter ACL (r = −0.71; p = 0.01), and lateral hamstring-quadriceps co-activation was related to ACL elongation (r = 0.46; p = 0.05). Net co-activation of the hamstrings and quadriceps muscles will likely reduce ACL elongation provided that the proportion of medial hamstring-quadriceps co-activation exceeds lateral.

1 September 2009
Verified
Conference Paper
Closed access
MPMark Pickering
Mark Pickering
AMAbdullah A. Muhit
Abdullah A. Muhit
JSJennie M. Scarvell
Jennie M. Scarvell
PSPaul N. Smith
Paul N. Smith
2D-3D image registration has been adopted in many clinical applications such as image-guided surgery and the kinematic analysis of bones in knee and ankle joints. In this paper we propose a new single-plane 2D-3D registration algorithm which requires far less iteration than previous techniques. The new algorithm includes a new multi-modal similarity measure and a novel technique for the analytic calculation of the required gradients. Our experimental results show that, when compared to existing gradient and non-gradient based techniques, the proposed algorithm has a wider range of initial poses for which registration can be achieved and requires significantly fewer iterations to converge to the true 3D position of the anatomical structure.