An Improved Differential Evolution Algorithm for Maritime Collision Avoidance Route Planning

High accuracy navigation and surveillance systems are pivotal to ensure efficient ship route planning and marine safety. Based on existing ship navigation and maritime collision prevention rules, an improved approach for collision avoidance route planning using a differential evolution algorithm was developed. Simulation results show that the algorithm is capable of significantly enhancing the optimized route over current methods. It has the potential to be used as a tool to generate optimal vessel routing in the presence of conflicts

An integrated solution for lane level irregular driving detection on highways

Global Navigation Satellite Systems (GNSS) has been widely used in the provision of Intelligent Transportation System (ITS) services. Current meter level system availability can fulfill the road level applications, such as route guide, fleet management and traffic control. However, meter level of system performance is not sufficient for the advanced safety applications. These lane level safety applications requires centimeter/decimeter positioning accuracy, with high integrity, continuity and availability include lane control, collision avoidance and intelligent speed assistance, etc. Detecting lane level irregular driving behavior is the basic requirement for these safety related ITS applications. The two major issues involved in the lane level irregular driving identification are accessing to high accuracy positioning and vehicle dynamic parameters and extraction of erratic driving behaviour from this and other related information. This paper proposes an integrated solution for the lane level irregular driving detection. Access to high accuracy positioning is enabled by GNSS and Inertial Navigation System (INS) integration using filtering with precise vehicle motion models and lane information. The detection of different types of irregular driving behaviour is based on the application of a Fuzzy Inference System (FIS). The evaluation of the designed integrated systems in the field test shows that 0.5 m accuracy positioning source is required for lane level irregular driving detection algorithm and the designed system can detect irregular driving styles

A breath-hold R2 mapping pulse sequence detects a decrease in myocardial ferritin iron after one-week of iron chelation

Oral Abstract Session XI – New CMR Methods Applied to Human Imaging: O69Intracellular ferritin iron is evidently in equilibrium with the cytosolic iron pool that can change rapidly with iron chelation. This study demonstrates the feasibility of quantitatively detecting short-term changes in myocardial iron produced by iron-chelating therapy using RR2 measurement.postprintThe 13th Annual Scientific Sessions of the Society for Cardiovascular Magnetic Resonance (SCMR), Phoenix, AZ., 21-24 January 2010. In Final Program of the 13th Annual Scientific Sessions of SCMR, 2010, p. 29, abstract no. O6

Characterisation of GNSS Space Service Volume

There is increasing demand for navigation capability for space vehicles. The idea to extend the application of Global Navigation Satellite Systems (GNSS) from terrestrial to space applications by the use of main beam and side lobe signals has been shown to be feasible. In order to understand the performance and the potential space applications GNSS can support, this paper characterises the Space Service Volume (SSV) in terms of the four parameters of minimum received power, satellite visibility, pseudorange accuracy and Geometric Dilution of Precision (GDOP). This new definition enables the position errors to be estimated. An analytical methodology is proposed to characterise minimum received power for the worst location. Satellite visibility and GDOP are assessed based on grid points at different height layers (to capture the relationship between height and visibility) for single and multiple GNSS constellations, the former represented by BeiDou III (BDS III) and the latter, BDS III in various combinations with GPS, GLONASS and GALILEO. Additional simulation shows that GNSS can potentially support lunar exploration spacecraft at the Earth phasing orbit. This initial assessment of SSV shows the potential of GNSS for space vehicle navigation

Validation of the perceived stress scale (Pss-10) in medical and health sciences students in Hong Kong

INTRODUCTION: The demanding nature of medical and health sciences studies can cause stress among students in these disciplines affecting their wellbeing and academic performance. The Perceived Stress Scale (PSS-10) is a widely used measure of perceived stress among medical students and healthcare professionals that has not yet been validated among medical and health sciences students in Hong Kong. The aim of this study is to establish the construct validity and reliability of the PSS-10 in this context. METHODS: 267 final year medical and health sciences students were surveyed using the PSS-10. The data were analysed using exploratory factor analysis for construct validity and Cronbach’s alpha coefficient and corrected item-total correlations for reliability. RESULTS: Exploratory factor analysis revealed a two-factor structure for PSS-10, with Cronbach’s alpha of 0.865 and 0.796, indicating good internal consistency. Corrected item-total correlations showed satisfactory correlation ranged from 0.539 to 0.748 for all items and their respective subscale. Both tests supported PSS-10 as a two-factor scale. CONCLUSIONS: The PSS-10 is a valid measure for assessing perceived stress in Hong Kong medical and health sciences students

UAV Downwash-Based Terrain Classification Using Wiener-Khinchin and EMD Filters

This work was partially funded by FCT Strategic Program UID/EEA/00066/203 of the Center of Technologies and System (CTS) of UNINOVA - Institute for the Development of new Technologies.Knowing how to identify terrain types is especially important in the autonomous navigation, mapping, decision making and detect landings areas. A recent area is in cooperation and improvement of autonomous behavior between robots. For example, an unmanned aerial vehicle (UAV) is used to identify a possible landing area or used in cooperation with other robots to navigate in unknown terrains. This paper presents a computer vision algorithm capable of identifying the terrain type where the UAV is flying, using its rotors’ downwash effect. The algorithm is a fusion between the frequency Wiener-Khinchin adapted and spatial Empirical Mode Decomposition (EMD) domains. In order to increase certainty in terrain identification, machine learning is also used. The system is validated using videos acquired onboard of a UAV with an RGB camera.authorsversionpublishe

Multi-Constellation GNSS Multipath Mitigation Using Consistency Checking

In a typical urban environment, a mixture of multipath-free, multipath-contaminated and non-line-of-sight (NLOS) propagated GNSS signals are received. The errors caused by multipath-contaminated and NLOS reception are the dominant source of reduced consumer-grade positioning accuracy in the urban environment. Many conventional receiver-based and antenna-based techniques have been developed to mitigate either multipath or NLOS reception with mixed success. Nevertheless, the positioning accuracy can be maximised based on the simple principle of selecting only those signals least contaminated by multipath and NLOS propagation to form the navigation solution. The advent of multi-constellation GNSS provides the opportunity to realise this technique that is potentially low-cost and effective for consumer-grade devices. It may also be implemented as an augmentation to other multipath mitigation techniques. The focus of this paper is signal selection by consistency checking, whereby measurements from different satellites are compared with each other to identify the NLOS and most multipath-contaminated signals. The principle of consistency checking is that multipath-contaminated and NLOS measurements produce a less consistent navigation solution than multipath-free measurements. RAIM-based fault detection operates on the same principle. Three consistency-checking schemes based on single-epoch least-squares residuals are assessed: single sweep, recursive checking and a hybrid version of the first two. Two types of weighting schemes are also considered: satellite elevation-based and signal C/N0-based weighting. The paper also discussed the different observables that may be used by a consistency-checking algorithm for different applications and their effect on detection sensitivity. Test results for the proposed algorithms are presented using data from both static positioning and stand-alone dynamic positioning experiments. The static data was collected using a pair of survey-grade multi-constellation GNSS receivers using both GPS and GLONASS signals at open sky and urban canyon locations, while the dynamic data was collected using a consumer-grade GPS/GLONASS receiver on a car in a mixed urban environment. Significant improvements in position domain are demonstrated using the weighted recursive methods in the open environments. However in the urban environments, there are insufficient directly received signals for the conventional RAIM-based signal selection to be effective all the time. Both positioning improvements and risky outliers are demonstrated. More advanced techniques have been identified for investigation in future research

Physics Opportunities of e+e- Linear Colliders

We describe the anticipated experimental program of an e+e- linear collider in the energy range 500 GeV -- 1.5 TeV. We begin with a description of current collider designs and the expected experimental environment. We then discuss precision studies of the W boson and top quark. Finally, we review the range of models proposed to explain the physics of electroweak symmetry breaking and show, for each case, the central role that the linear collider experiments will play in elucidating this physics. (to appear in Annual Reviews of Nuclear and Particle Science)Comment: 93 pages, latex + 23 figures; typos corrections + 1 reference adde

Assessment of the EarlyCDT-Lung test as an early biomarker of lung cancer in ever-smokers - A retrospective nested case-control study in two prospective cohorts

The EarlyCDT-Lung test is a blood-based autoantibody assay intended to identify high-risk individuals for low-dose computed tomography lung cancer screening. However, there is a paucity of evidence on the performance of the EarlyCDT-Lung test in ever-smokers. We conducted a nested case-control study within two prospective cohorts to evaluate the risk-discriminatory performance of the EarlyCDT-Lung test using pre-diagnostic blood samples from 154 future lung cancer cases and 154 matched controls. Cases were selected from those who had ever smoked and had a pre-diagnostic blood samples less than 3 years prior to diagnosis. Conditional logistic regression was used to estimate the association between EarlyCDT-Lung test results and lung cancer risk. Sensitivity and specificity of the EarlyCDT-Lung test were calculated in all subjects and subgroups based on age, smoking history, lung cancer stage, sample collection time before diagnosis and year of sample collection. The overall lung cancer odds ratios were 0.89 (95% CI, 0.34-2.30) for a moderate risk EarlyCDT-Lung test result and 1.09 (95% CI, 0.48-2.47) for a high-risk test result compared to no significant test result. The overall sensitivity was 8.4% (95% CI, 4.6-14) and overall specificity was 92% (95% CI, 87-96) when considering a high-risk result as positive. Stratified analysis indicated higher sensitivity (17%, 95% CI, 7.2-32.1) in subjects with blood drawn up to 1 year prior to diagnosis. In conclusion, our study does not support a role of the EarlyCDT-Lung test in identifying the high-risk subjects in ever-smokers for lung cancer screening in the EPIC and NSHDS cohorts

Infrequent Detection of KI, WU and MC Polyomaviruses in Immunosuppressed Individuals with or without Progressive Multifocal Leukoencephalopathy

Conflicting prevalence of newly identified KI(KIPyV), WU(WUPyV) and Merkel Cell Carcinoma(MCPyV) polyomaviruses have been reported in progressive multifocal leukoencephalopathy(PML) patient samples, ranging from 0 to 14.3%. We analyzed the prevalence of these polyomaviruses in cerebrospinal fluid(CSF), peripheral blood mononuclear cells(PBMC), and bone marrow samples from PML patients, immunosuppressed individuals with or without HIV, and multiple sclerosis(MS) patients. Distinct PCR tests for KIPyV, WUPyV and MCPyV DNA performed in two independent laboratories detected low levels of MCPyV DNA only in 1/269 samples. The infrequent detections of these viruses in multiple samples from immunosuppressed individuals including those with PML suggest that their reactivation mechanisms may be different from that of JC polyomavirus (JCPyV) and that they do not play a role in the pathogenesis of PML