Behavioural and sensory aspects of predation in -mustelids: studies on the sensory capabilities of the weasel, Mustela nivalis L. And the polecat, Mustela putorlus L., with particular reference to predatory behaviour

The relative importance of vision, audition and olfaction to weasels and polecats was determined by training the predators to find a mouse located in a predator-proof container within a small arena. The diversity of sensory information available to the predators had an effect on the time taken to find the mouse with this being shorter when three senses could be used compared to when one sensory modality was available. Vision and olfaction (air-borne scent) were equivalent, with audition being less important. The mouse was found quicker using substrate-scent cues than with air-borne olfactory cues. There was no difference in the relative importance of the senses between the predators. The removal of movement cues had a significant effect on the behaviour of the weasels. The visual movement discrimination ability of both species was investigated using a horizontally-moving spot on a cathode-ray oscilloscope screen. Thresholds were determined for the discrimination of the direction of a fast-moving stimulus and were equivalent in the polecat and weasel. The mean threshold for polecats was 292cms(^-1) and for weasels was 267cms(^-1). The movement detection ability of the weasel was consistent over a range of stimulus radiant intensities (35.4-2.0x10(^5) µWsteradian(^-l)) and discrimination distances (10-50cm), although there was a slight decrease in threshold at the furthest distance used and when the distance traversed by the stimulus was short. A relative velocity discrimination task was devised in which polecats were trained to discriminate differences in speed between identical objects moving in opposite directions in the horizontal plane. They could detect velocity differences of 20% and showed a tendency to select the slower-moving of the two stimuli. Polecats and weasels do not specialize in the use of a particular distance sense to locate potential prey. In terms of their movement detection ability and the relative importance of vision they are intermediate between strictly nocturnal and diurnal species, which is probably attributable to their predominately crepuscular activity pattern

Implementation of target tracking in Smart Wheelchair Component System

Independent mobility is critical to individuals of any age. While the needs of many individuals with disabilities can be satisfied with power wheelchairs, some members of the disabled community find it difficult or impossible to operate a standard power wheelchair. This population includes, but is not limited to, individuals with low vision, visual field neglect, spasticity, tremors, or cognitive deficits. To meet the needs of this population, our group is involved in developing cost effective modularly designed Smart Wheelchairs. Our objective is to develop an assistive navigation system which will seamlessly integrate into the lifestyle of individual with disabilities and provide safe and independent mobility and navigation without imposing an excessive physical or cognitive load. The Smart Wheelchair Component System (SWCS) can be added to a variety of commercial power wheelchairs with minimal modification to provide navigation assistance. Previous versions of the SWCS used acoustic and infrared rangefinders to identify and avoid obstacles, but these sensors do not lend themselves to many desirable higher-level behaviors. To achieve these higher level behaviors we integrated a Continuously Adapted Mean Shift (CAMSHIFT) target tracking algorithm into the SWCS, along with the Minimal Vector Field Histogram (MVFH) obstacle avoidance algorithm. The target tracking algorithm provides the basis for two distinct operating modes: (1) a "follow-the-leader" mode, and (2) a "move to stationary target" mode.The ability to track a stationary or moving target will make smart wheelchairs more useful as a mobility aid, and is also expected to be useful for wheeled mobility training and evaluation. In addition to wheelchair users, the caregivers, clinicians, and transporters who provide assistance to wheelchair users will also realize beneficial effects of providing safe and independent mobility to wheelchair users which will reduce the level of assistance needed by wheelchair users

Moving object extraction by watershed algorithm considering energy minimization

金沢大学大学院自然科学研究科情報システムMPEG-4, which is a video coding standard, supports object-based functionalities for high efficiency coding. MPEG-7, a multimedia content description interface, handles the object data in, for example, retrieval and/or editing systems. Therefore, extraction of semantic video objects is an indispensable tool that benefits these newly developed schemes. In the present paper, we propose a technique that extracts the shape of moving objects by combining snakes and watershed algorithm. The proposed method comprises two steps. In the first step, snakes extract contours of moving objects as a result of the minimization of an energy function. In the second step, the conditional watershed algorithm extracts contours from a topographical surface including a new function term. This function term is introduced to improve the estimated contours considering boundaries of moving objects obtained by snakes. The efficiency of the proposed approach in moving object extraction is demonstrated through computer simulations. © Springer-Verlag Berlin Heidelberg 2007

Amblyopia and real-world visuomotor tasks

A question of increasing interest to the basic science and clinical management communities during the past decade is whether children and adults with amblyopia and associated binocular visual abnormalities experience difficulties in executing real-world actions, to which vision normally makes an important functional contribution. Here we provide objective evidence that they do, by reviewing quantitative data from a number of studies comparing their performance with that of matched normally sighted subjects on a range of everyday visuomotor tasks. Because in real life, these tasks (grasping objects, walking, driving, reading) are habitually performed with both eyes open, our focus is on their binocular skill deficits, rather than those with their amblyopic eye alone. General findings are that individuals with abnormal binocularity show impairments in critical aspects of motor control--movement speed, accuracy or both--on every one of these activities, the extent of which correlates with their loss of stereoacuity, but not the severity of their amblyopia. Impairments were especially marked when the task was time-limited or novel. Implications are that children and adults with severely reduced or absent binocularity may be accident-prone when required to respond rapidly to unexpected situations and that amblyopia management should focus more attention on evaluating and restoring stereoacuity and stereomotion processing

Seeing Past Causes: Causation and Covariation in Informational Teleosemantics

Neander (2017) presents a causal version of informational teleosemantics (CT), where a non-conceptual state R has the content F if and only if R has the function of being caused by F. In contrast, probabilistic versions of informational teleosemantics (PT) claim that R has the content F if and only if R has the function of covarying with F. These two theories ascribe different contents to representational states since PT allows R to have the content F when R non-causally covaries with F. First, I argue that CT is incapable of serving one of the main explanatory aims of a theory of content, which is to fully explain behavior. Second, I defend PT against the charge of indeterminacy, arguing that when PT ascribes multiple contents, these contents serve distinct explanatory aims

Planning Framework for Robotic Pizza Dough Stretching with a Rolling Pin

Stretching a pizza dough with a rolling pin is a nonprehensile manipulation. Since the object is deformable, force closure cannot be established, and the manipulation is carried out in a nonprehensile way. The framework of this pizza dough stretching application that is explained in this chapter consists of four sub-procedures: (i) recognition of the pizza dough on a plate, (ii) planning the necessary steps to shape the pizza dough to the desired form, (iii) path generation for a rolling pin to execute the output of the pizza dough planner, and (iv) inverse kinematics for the bi-manual robot to grasp and control the rolling pin properly. Using the deformable object model described in Chap. 3, each sub-procedure of the proposed framework is explained sequentially