Direct model fitting to combine dithered ACS images

The information lost in images of undersampled CCD cameras can be recovered with the technique of `dithering'. A number of subexposures is taken with sub-pixel shifts in order to record structures on scales smaller than a pixel. The standard method to combine such exposures, `Drizzle', averages after reversing the displacements, including rotations and distortions. More sophisticated methods are available to produce, e.g., Nyquist sampled representations of band-limited inputs. While the combined images produced by these methods can be of high quality, their use as input for forward-modelling techniques in gravitational lensing is still not optimal, because the residual artefacts still affect the modelling results in unpredictable ways. In this paper we argue for an overall modelling approach that takes into account the dithering and the lensing without the intermediate product of a combined image. As one building block we introduce an alternative approach to combine dithered images by direct model fitting with a least-squares approach including a regularization constraint. We present tests with simulated and real data that show the quality of the results. The additional effects of gravitational lensing and the convolution with an instrumental point spread function can be included in a natural way, avoiding the possible systematic errors of previous procedures.Comment: 6 pages, 8 figure

A location-aware embedding technique for accurate landmark recognition

The current state of the research in landmark recognition highlights the good accuracy which can be achieved by embedding techniques, such as Fisher vector and VLAD. All these techniques do not exploit spatial information, i.e. consider all the features and the corresponding descriptors without embedding their location in the image. This paper presents a new variant of the well-known VLAD (Vector of Locally Aggregated Descriptors) embedding technique which accounts, at a certain degree, for the location of features. The driving motivation comes from the observation that, usually, the most interesting part of an image (e.g., the landmark to be recognized) is almost at the center of the image, while the features at the borders are irrelevant features which do no depend on the landmark. The proposed variant, called locVLAD (location-aware VLAD), computes the mean of the two global descriptors: the VLAD executed on the entire original image, and the one computed on a cropped image which removes a certain percentage of the image borders. This simple variant shows an accuracy greater than the existing state-of-the-art approach. Experiments are conducted on two public datasets (ZuBuD and Holidays) which are used both for training and testing. Morever a more balanced version of ZuBuD is proposed.Comment: 6 pages, 5 figures, ICDSC 201

Metabolism of the dihydropyridine calcium channel blockers mebudipine and dibudipine by isolated rat hepatocytes

The prototype 1,4-dihydropyridine (1,4-DHP) nifedipine, indicated for the management of hypertension and angina pectoris, has drawbacks of rapid onset of vasodilating action and a short half-life. Several newer analogues have been designed to offset these problems and these include mebudipine and dibudipine. These analogues contain t-butyl substituents that have been selected to alter the fast metabolism without altering pharmacological activity. In this study, the metabolism of mebudipine and dibudipine by isolated rat hepatocytes has been investigated. These compounds were extensively metabolized in 2 h by oxidative pathways, analogous to those known for nifedipine, and by O-glucuronidation after hydroxylation of the t-butyl substituents. The in-vitro half-lives of mebudipine (22 ± 7.1 min) and dibudipine (40 ± 9.8 min) were significantly longer than that of nifedipine (5.5 ± 1.1 min), which was investigated in parallel in this study. These newer 1,4-DHPs address the problem of the short half-life of nifedipine and have potential for further development in view of their comparable potency to nifedipine

Persistent operation of mobile robots

Success of numerous unmanned mobile missions in space, air, ground, and water is measured by the ability of the robots to usefully operate for extended time in dynamic and uncertain environments. This talk will provide an overview of the recent progress towards performing autonomous long-term missions. The approach includes task and energy routing scheduling, efficient path planning and coordination, and low-infrastructure platforms. The goal is to provide practical solutions by lowering deployment and operating costs, while also increasing efficiency, endurance and persistence during complex missions like disaster responses and long-term science discoveries.https://digitalcommons.mtu.edu/techtalks/1026/thumbnail.jp

A comprehensive review: Evaluation of AC Induced Voltage on Buried Pipeline Near Overhead Transmission Lines and Mitigation Techniques Comparison

Steel pipelines used to transport gas and other petroleum products are protected by insulating coatings as well as cathodic protection systems. These pipelines sometimes are passed near the power lines, causing induced AC voltage on them. Increasing the AC voltage amplitude on the buried pipelines will increase the risk of electric shock, electric sparking between the equipment connected to the pipeline and the ground or adjacent metal structures, increasing the rate of insulation damage to the pipelines, disrupting the functioning of the cathodic protection system as well as increasing the AC corrosion of pipelines. Therefore, it is necessary to study and evaluate the factors affecting the inductive AC voltage level and provide effective solutions to reduce its destructive effects. In this paper, the inductive voltage of overhead lines on buried metal pipeline has been investigated under normal conditions of power system. The amount of induced voltage on the pipelines depends on some factors such as the current of the transmission line, the number of transmission line circuits, the arrangement of the phases, and the distance between the transmission line and the underground pipeline

Dusty space plasma diagnosis using temporal behavior of polar mesospheric summer echoes during active modification

The objective of this paper is to study the effect of different plasma and dust parameters on Polar Mesospheric Summer Echoes (PMSE) temporal behavior after turn-on and turn-off of radio wave heating and to use these responses to diagnose the properties of the dust layer. The threshold radar frequency and dust parameters for the enhancement or suppression of radar echoes after radio wave heating turn-on are investigated for measured mesospheric plasma parameters. The effect of parameters such as the electron temperature enhancement during heating, dust density, dust charge polarity, ion-neutral collision frequency, electron density and dust radius on the temporal evolution of electron irregularities associated with PMSE are investigated. The possible diagnostic information for various charged dust and background plasma quantities using the temporal behavior of backscattered radar power in active experiments is discussed. The computational results are used to make predictions for PMSE active modification experiments at 7.9, 56, 139, 224 and 930MHz corresponding to existing radar facilities. Data from a 2009 VHF (224 MHz) experiment at EISCAT is compared with the computational model to obtain dust parameters in the PMSE

The Power of Subliminal vs. Supraliminal versions of the Combi Emotional Stroop Test in Measuring Attentional Bias for test and Social Anxiety

The present study was carried out with the purpose of investigating cognitive attentional bias in non-clinical populations as well as evaluation of attentional bias in groups with high social and test anxiety on two subliminal and supraliminal levels. First, 300 third-grade female high-school students filled out test anxiety and social anxiety questionnaires. Afterwards, 60 high-anxiety students were selected as the subjects of the study on the basis of social anxiety (N=30) and test anxiety (n=30) variables. Moreover, in each group, 15 students were assessed as the control group. In the second stage of the study, using the Combined Emotional Stroop Test, attentional bias of the participants was assessed on two subliminal and supraliminal levels in response to anxiety stimulants. The results showed that response times and interference scores of the experimental groups were not significantly different from those of the control groups on both subliminal and supraliminal levels