There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

CA : A Cancer Journal for Clinicians

Introduction to linear and nonlinear programming

Bilateral teleoperation: An historical survey

Scientific microgravity experiments conducted on platforms such as the Soviet Mir space station and the U.S. Space Shuttle indicated that the microgravity environment is contaminated with disturbances which result in the reduction of a gravity quality, from micro-g to milli-g. This paper describes the vibration isolation technology developed by the Canadian Space Agency, the 1DOF Large Motion Isolation Mount (LMIM) and the 3DOF LMIM, for the KC-135 aircraft. The results of the developmental activity are presented, and the applicability of the approach taken to the Space Shuttle, Space Station Freedom, and the Mir space station is discussed.

Development and performance of a three degree of freedom large motion vibration isolation mount for the KC-135 aircraft

In "human teleoperation" (HT), mixed reality (MR) and haptics are used to tightly couple an expert leader to a human follower [1]. To determine the feasibility of HT for teleultrasound, we quantify the ability of humans to track a position and/or force trajectory via MR cues. The human response time, precision, frequency response, and step response were characterized, and several rendering methods were compared.Volunteers (n=11) performed a series of tasks as the follower in our HT system. The tasks involved tracking pre-recorded series of motions and forces while pose and force were recorded. The volunteers then performed frequency response tests and filled out a questionnaire.Following force and pose simultaneously was more difficult but did not lead to significant performance degradation versus following one at a time. On average, subjects tracked positions, orientations, and forces with RMS tracking errors of [Formula: see text] mm, [Formula: see text], [Formula: see text] N, steady-state errors of [Formula: see text] mm, [Formula: see text] N, and lags of [Formula: see text] ms, respectively. Performance decreased with input frequency, depending on the input amplitude.Teleoperating a person through MR is a novel concept with many possible applications. However, it is unknown what performance is achievable and which approaches work best. This paper thus characterizes human tracking ability in MR HT for teleultrasound, which is important for designing future tightly coupled guidance and training systems using MR. 

/pdf/human-as-a-robot-performance-in-mixed-reality-teleultrasound-tq1tm8q4.pdf

Human-as-a-robot performance in mixed reality teleultrasound

Registration of histological slices to volumetric imaging of the prostate is an important task that can be used to optimize imaging for cancer detection. Such registration is challenging due to change in volume of the specimen during xation, and misalignment of the histological slices during preparation and digital scanning. In this work we propose a multiple-slice to volume registration method in which a stack of equispaced, uniaxial but unaligned 2D contours, extracted from digitally scanned whole-mount histological slices, is registered to a 3D surface, extracted from a volumetric image of the prostate. Initially, the stack of unaligned contours is coarsely aligned to the surface as a whole. Then, each contour is nely registered to the surface while being conned to its plane along the sectioning axis. We incorporate the method in a particle ltering framework to compensate for the high dimensionality of the search space and multi-modal nature of the problem. Moreover, such framework allows modeling the uncertainty in the segmentation of the contours and surface, in order to derive optimal registration parameters in a Bayesian approach. The proposed algorithm is demonstrated and evaluated on both synthetic and clinical data. The mean area overlap of the registered gland and the segmented histology was found to be 90.2%, with a mean registration error of 1.8mm between visible landmarks.

Registration of whole-mount histology and tomography of the prostate using particle ltering

Treatment planning in low-dose-rate prostate brachytherapy (LDR-PB) aims to produce arrangement of implantable radioactive seeds that deliver a minimum prescribed dose to the prostate whilst minimizing toxicity to healthy tissues. There can be multiple seed arrangements that satisfy this dosimetric criterion, not all deemed 'acceptable' for implant from a physician's perspective. This leads to plans that are subjective to the physician's/centre's preference, planning style, and expertise. We propose a method that aims to reduce this variability by training a model to learn from a large pool of successful retrospective LDR-PB data (961 patients) and create consistent plans that mimic the high-quality manual plans. Our model is based on conditional generative adversarial networks that use a novel loss function for penalizing the model on spatial constraints of the seeds. An optional optimizer based on a simulated annealing (SA) algorithm can be used to further fine-tune the plans if necessary (determined by the treating physician). Performance analysis was conducted on 150 test cases demonstrating comparable results to that of the manual prehistorical plans. On average, the clinical target volume covering 100% of the prescribed dose was 98.9% for our method compared to 99.4% for manual plans. Moreover, using our model, the planning time was significantly reduced to an average of 2.5 mins/plan with SA, and less than 3 seconds without SA. Compared to this, manual planning at our centre takes around 20 mins/plan.

Rapid treatment planning for low-dose-rate prostate brachytherapy with TP-GAN

We describe in this paper an extension of the 2-DOF fine positioner reported in 1985 [1]. The extension combines x and y translational motion with rotation ρz about the z axis, allowing general planar alignment tasks to be performed. The device is a compact combination of 3-D OF linear motor, flexure springs, position sensor and digital controller. The semiconductor lateral-effect method used for position sensing is extended to include measurement of rotation. A new suspension system based on flexing rods substantially cancels unwanted z motion and motor gap change associated with the 2-DOF device, but introduces highly resonant structural vibration modes that need to be controlled. This paper briefly describes the new device, discusses the issues involved in controlling it, presents several controller designs, and reports their performance.

Septimiu E. Salcudean

Papers

Development and performance of a three degree of freedom large motion vibration isolation mount for the KC-135 aircraft

Human-as-a-robot performance in mixed reality teleultrasound

Registration of whole-mount histology and tomography of the prostate using particle ltering

Rapid treatment planning for low-dose-rate prostate brachytherapy with TP-GAN

Control issues for a flexure-suspension three-dof robotic fine positioning device