Biomedical Engineering

The current aging population and the rise in the incidence of age related fractures pose a huge burden on the health services. Current therapies including the use of allografts and autografts are limited.  An injectable in situ solidifying polymer based scaffold, which can be injected into cavities of irregular shape and size in a minimally invasive manner could offer a superior alternative. The scaffold could be designed to release BMP2 in situ, while degrading and allowing the regeneration of bone tissues. The aim of this project was to develop an injectable scaffold formulation that could easily be injected at room temperature and hardened at body temperature, producing a scaffold with sufficient mechanical properties to withstand in vivo loading. The entrapment of protein molecules into PLGA [Poly(lactic-co-glycolic) acid] microspheres was also optimised. These particles were then used to prepare injectable scaffolds and the release of protein was determined over time.

Among all agro industrial material hydrolyzing enzymes, xylanases gained importance due to their role in production of xylose based products of industrial importance. An isolated fungal strain, Aspergillus sp. RSP-6, having potential in xylanase production specific to palm fiber was characterized for enzyme production properties under solid suspend fermentation environments. Effective enzyme production was achieved with palm fiber as carbon source compared to all other tested agro materials and carbohydrates. Among different nitrogen sources, beef extract supported maximum enzyme production. Various fermentation parameters (pH of the medium, particle size and its concentration, incubation time and medium volume in addition to carbon and nitrogen sources) influenced the xylanase production. Maximum enzyme production of 62,480 U/l was observed in the medium of pH 3.0 containing 2% palm material having particle size of 2.8–1.4 mm and 1% (w/v) beef extract in presence of other mineral salts in 144 hours of incubation. Over all, the enzyme production has increased significantly from 20,000 to 62,480 U/ l under optimized environment and observed to be constitutive in nature in this fungal strain.

Diffuse optical topography (DOT) is a non-invasive technique that uses near-infrared light to measure changes in brain activity through an array of sensors placed on the surface of the head. The reconstruction of accurate spatial images of brain activity from optical measurements represents an ill-posed and underdetermined problem that requires regularization. We describe a novel image reconstruction approach which uses surface-based wavelets derived from structural MRI to incorporate high-resolution anatomical information into the reconstruction of diffuse optical images of brain activity. This approach is used to approximate brain activation patterns through the reconstruction and presentation of topographical maps of brain activation directly onto the folded surface of the cortex. The wavelet coefficients are directly estimated by a truncated singular-value decomposition and pseudo-inversion of the wavelet projection of the optical forward model. A unique choice of a reconstruction metric derived from Shannon entropy quantifies the sparse loading of the wavelet coefficients and is used to determine the optimal truncation and regularization of this inverse model.

Near-infrared spectroscopy is a non-invasive neuroimaging method which uses light to measure changes in cerebral blood oxygenation associated with brain activity. In this work, we demonstrate the ability to record and analyze images of brain activity in real-time using a 16-channel continuous wave optical NIRS system. We demonstrate a novel real-time analysis framework using an adaptive Kalman filter and a state-space model based on a canonical general linear model of brain activity. We show that our adaptive model has the ability to estimate single-trial brain activity events as we apply this method to track and classify experimental data acquired during an alternating bilateral finger opposition task.

Mucor rouxii biomass (MRB) was found to be most potent sorbent for the removal of copper from its aqueous solution. Maximum adsorption was noted within pH range 5.0–6.0, and the process follows Langmuir adsorption isotherm (r2 = 0.998). Adsorption process is very fast initially and reaches equilibrium very quickly following pseudo second order rate kinetics. Amino, carboxyl and phosphate groups present on the cell surface of the biomass are involved in chemical interaction with copper ion as revealed from FTIR and SEM-EDX study and also by blocking experiments. Both SEM and AFM micrographs revealed the formation of metal nanostructure on the biomass surface due to copper adsorption. Biomass surface modification indicates the major involvement of amino functional group for the binding probably through the chelation. Copper ion can be eluted from the adsorbed biomass with 0.1 M hydrochloric acid.

We report a cross-modal translation system from Hindi strings to Indian Sign Language (ISL) for possible use in the Indian Railways reservation counters. INGIT adopts a semantically mediated formulaic framework for Hindi-ISL mapping. An in-depth investigation into the structure of ISL forms the groundwork for INGIT. Some representational and mapping issues concerning cross-modal translation are identified and an implementation design is evolved. We adopt the Construction Grammar approach for handling formulaic inputs in terms of a construction lexicon with single constituents as well as larger phrases, with direct semantic mappings at each level. We present results based on a small corpus collected at a railway counter, for which translations were validated from native ISL signers. The work builds upon a semantic module worked out for Hindi and ISL.

This paper presents an efficient model for automatic detection and extraction of blood vessels in ocular fundus images. The model is formed using a combination of the concept of ribbon snakes and twin snakes. On each edge, the twin concept is introduced by using two snakes, one inside and one outside the boundary. The ribbon concept integrates the pair of twins on the two vessel edges into a single ribbon. The twins maintain the consistency of the vessel width, particularly on very blurred, thin and noisy vessels. The model exhibits excellent performance in extracting the boundaries of vessels, with improved robustness compared to alternative models in the presence of occlusion, poor contrast or noise. Results are presented which demonstrate the performance of the discussed edge extraction method, and show a significant improvement compared to classical snake formulations.

We describe an approach to integrated robot control, high-level planning, and action effect learning that attempts to overcome the representational difficulties that exist between these diverse areas. Our approach combines ideas from robot vision, knowledge level planning, and connectionist machine learning, and focuses on the representational needs of these components.We also make use of a simple representational unit called an instantiated state transition fragment (ISTF) and a related structure called an object-action complex (OAC). The goal of this work is a general approach for inducing high-level action specifications, suitable for planning, from a robot’s interactions with the world. We present a detailed overview of our approach and show how it supports the learning of certain aspects of a high-level representation from low-level world state information.

"Preimplantation tissue typing has been proposed as a method for creating a tissue matched child that can serve as a haematopoietic stem cell donor to save its sick sibling in need of a stem cell transplant. Despite recent promising results, many people have expressed their disapproval of this method. This paper addresses the main concerns of these critics: the risk of preimplantation genetic diagnosis (PGD) for the child to be born; the intention to have a donor child; the limits that should be placed on what may be done to the donor child, and whether the intended recipient can be someone other than a sibling. The author will show that these concerns do not constitute a sufficient ground to forbid people to use this technique to save
not only a sibling, but also any other loved one’s life. Finally, the author briefly deals with two alternative scenarios: the creation of a human leukocyte antigen (HLA) matched child as an insurance policy, and the banking of HLA matched embryos."

The present paper investigates the long-term functionality of an ex vivo gene therapy approach based on cell microencapsulation for the continuous delivery of erythropoietin (EPO) without implementation of immunosuppressive protocols. Polymer icrocapsules (0.5 ml) loaded with EPOsecreting C2C12 myoblasts and releasing 15,490 F 600 IU EPO/24 h were implanted in the peritoneum and subcutaneous tissue of syngeneic and allogeneic mice. High and constant hematocrit levels were maintained for more than 100 days in all implanted mice. Capsules retrieved from the peritoneum were free-floating or forming small capsule clusters, and we detected only a weak fibroblast outgrowth in capsules adhered to organs, whereas capsules explanted from the subcutaneous region appeared altogether as a richly vascularized structure with no signs of major host reaction. Interestingly, the functionality of capsules implanted in the allogeneic mice persisted until day 210 after implantation. These results highlight the feasibility of cell encapsulation technology for the long-term delivery of EPO independent of the method of administration and the mouse strain.

Purpose: The matching of prosthetic devices to the needs of the individual is a challenge for providers
and patients. The aims of this study are to explore the values and preferences that prosthetic users
have of their prosthetic devices; to investigate users’ perceptions of alternative prosthetic options and to
demonstrate a novel method for exploring the values and preferences of prosthetic users.
Methods: This study describes four case studies of upper limb and lower limb high tech and
conventional prosthetic users. Participants were interviewed using the repertory grid technique (RGT), a
qualitative technique to explore individual values and preferences regarding specific choices and events.
Results: The participants generated distinctive patterns of personal constructs and ratings regarding
prosthetic use and different prosthetic options available. The RGT produced a unique profile of
preferences regarding prosthetic technologies for each participant.
Conclusions: User choice is an important factor when matching prosthetic technology to the user.
The consumer’s values regarding different prosthetic options are likely to be a critical factor in
prosthetic acceptance and ultimate quality of life. The RGT offers a structured method of exploring
these attitudes and values without imposing researcher or practitioner bias and identifies personalized
dimensions for providers and users to evaluate the individuals’ preferences in prosthetic technology.

This paper presents a nouvelle and non-destructiveBroadbandcharacterizationmethodwhichusesacoplanarlineforthemeasurementofthecomplexpermittivityoflineardielectricmaterialsandprecisely,thatofferroelectricthinfilms.Themethodusesthetransmissioncoefficientandthequasi-TEManalysistofindtheeffectivepermittivityofthemultilayersystem,andthenthecoplanarconformalmappingtechniqueisemployedtoextracttherelativepermittivityofthethinlayer.Comparingourresultstothoseofcavityresonatormethodat12GHzshowsagoodagreement.Themeasurementisdoneinthemicrowavefrequencyband(45MHz–20GHz).

We describe the synthesis of metal chelating polymers based on polyaspartamide and polyglutamide backbones as carriers for 111 In in radioimmunoconjugates. These polymers [PAsp(DTPA), PGlu(DTPA)] have a biotin end group and diethylenetriaminepentaacetic acid (DTPA) chelators attached to the primary amines of the diethylenetriamine (DET) pendant groups of biotin-poly{N′-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} [PAsp(DET)] and of biotin-poly{N′-[N-(2-aminoethyl)-2-aminoethyl]glutamide} [PGlu(DET)]. Like Asn-containing proteins and polypeptides, polyaspartamides undergo uncatalyzed degradation under model physiological conditions (10 mM phosphate buffer, pH 7.4, 150 mM NaCl)

Author disambiguation is the problem of determining whether records in a publications database refer to the same person. A common supervised machine learning approach is to build a classifier to predict whether a pair of records is coreferent, followed by a clustering step to enforce transitivity. However, this approach ignores powerful evidence obtainable by examining sets (rather than pairs) of records, such as the number of publications or co-authors an author has. In this paper we propose a representation that enables these first-order features over sets of records. We then propose a training algorithm well-suited to this representation that is (1) error-driven in that training examples are generated from incorrect predictions on the training data, and (2) rankbased in that the classifier induces a ranking over candidate predictions. We evaluate our algorithms on three author disambiguation datasets and demonstrate error reductions of up to 60% over the standard binary classification approach.

Object-Process Methodology (OPM), which is a holistic approach to modeling and evolving systems, views objects and processes as two equally important entities that describe the system’s structure and behavior in a single model. Unified Modeling Language (UML), which is the standard object-oriented modeling language for software systems, separates the system model into various aspects, each of which is
represented in a different view (diagram type). The exponential growth of the Web and the progress of Internet-based architectures have set the stage for the proliferation of a variety of Web applications, which are classified as hybrids between hypermedia and information systems. Such applications require a modeling approach that is capable of clearly specifying aspects of their architecture, communication, and distributive nature. Since UML and OPM are two candidates for this task, this study has been designed to establish the level of comprehension and the quality of the constructed Web application models using each one of these two approaches. In the experiment we carried out, third year undergraduate information systems engineering students were asked to respond to comprehension and construction questions about two representative Web application models. The comprehension questions related to the system’s structure, dynamics, and distribution aspects. The results suggest that OPM is better than UML in modeling the dynamics aspect of the Web applications. In specifying structure and distribution aspects, there were no significant differences. The results further suggest that the quality of the OPM models students built in the construction part were superior to that of the corresponding UML models.

Keywords: Object-Process Methodology, Unified Modeling Language, Web applications, software development,
IS development methodologies, object-oriented design, functional design.

The project discussed in this paper has been conducted as part of the Autonomatic research cluster based at University College Falmouth. The cluster is focused on research projects that explore the use of digital production technologies within the context of designer maker and craft practice.

My project is concerned with developing more direct control of processes that are typically automated by CAD software and CAM tools. I believe the use of these standardised tools limit the ability of the maker to create unique visual vocabularies.

It is possible to view the aesthetic qualities emerging in the new genre of ‘digital craft’ - such as the use of triangulation and the quality of line produced by generic pre-set machine parameters - as a temporary phase in the digital craft timeline. As more makers adopt digital technologies, we may discover that these visual aesthetic qualities are more attributable to the technology than the maker rather than being understood as unique. The author believes it is therefore important for makers wishing to further their practice in this field to seek ways in which they can gain greater control over the processes and tools they are using.

This paper presents research that explores ways in which programmed mathematical elements in 3D CAD can be deconstructed and manipulated throughout the design and production phases. Employing an iterative designing and making process I have used this ‘hand’ manipulated CAD data to drive CNC machine tools in highly specified ways. This has lead to an in depth understanding of the inter-relationship between CAD and CAM as intrinsic to the development of unique aesthetic qualities. The development of a dialogue between CAD code and CNC tooling has resulted in a greater level of control enabling the realisation of complex and completely controlled patterning on 3D forms that go beyond the restrictions of standard toolsets.

This research has resulted in a range of 3D aluminium sample pieces that I have used to create a visual knowledge bank which documents the relationship between software input, machine parameters and their effects on the visual form. This knowledge has been applied to my working digital design practice enabling me to create aluminium platters and beakers that counter the affects of automation.

This paper aims to offer other makers methods which allow the potential for 'hacking' into code in order to expand the possibilities for control and creative engagement with digital tools and thereby offering more unique opportunities for developing visual vocabularies than using standard toolsets alone.

Musculoskeletal injuries are a leading occupational hazard. Apart from the physical consequences of such injuries, the social and emotional effects are serious for the injured workers, favoring a downward spiral toward chronicity. The human and economic costs of chronicity are substantial for workers, employers, compensation agencies, and the health care system. A low-cost intervention that arrests this downward spiral would be highly desirable. We decided to explore this possibility in our local setting, Edmonton, Alberta.

Automated collection of environmental data may be accomplished with wireless sensor networks (WSNs). In this paper, a general discussion of WSNs is given for the gathering of data for educational research. WSNs enhance the scope of a researcher to include multiple streams of data: environmental, cyberdata, video, and RFID. A brief overview of the technology prepares the exploration of a setting used for outdoor learning.

Natural plaque biofilms were generated in vivo on natural enamel surfaces using the device described by Robinson et al 1997. After 7 days these were recovered from the mouth and immersed in solutions of the therapeutic to be tested. After designated time intervals, devices were removed and immediately snap frozen using liquid nitrogen. After lyophilisation the accumulated biofilm was embedded in methacrylate and sectioned at 5-micron intervals from saliva interface to the enamel surface. Groups of 10 sections were pooled for determination of therapeutic content and between the 5th and 6th section a pair of 2μm sections was collected for image analysis from which biomass volume and distribution were determined. Penetration for all compounds examined was limited in 30 seconds to the outer third or so of the plaque layer. At 2 minutes concentrations in the outer regions increased but little more penetrated to the enamel surface. For fluoride, only after 30 minutes was there a semblance of equilibration with the supernatant solution. The distribution profiles obtained were compared with biomass distribution and were closely related to the surface area to mass curves suggesting that uptake may be dictated by available surface area. This may also limit penetration. From preliminary investigations, where radioactive materials were used in vitro, amine fluoride was often seen to reside at the surfaces of biomass. The much more hydrophobic riclosan, however, seemed to be located within the biomass, possibly in the region of bacterial cells.

High-resolution three-dimensional (3-D) positron emission tomography (PET) scanners with high count rate performance, such as the quad-high density avalanche chamber (HIDAC), place new demands on image reconstruction algorithms due to the large quantities of high-precision list-mode data which are produced. Therefore, a reconstruction algorithm is required which can, in a practical time frame, reconstruct into very large image arrays (submillimeter voxels, which range over a large field of view) whilst preferably retaining the precision of the data. This work presents an algorithm which meets these demands: one-pass list-mode expectation maximization (OPL-EM) algorithm. The algorithm operates directly on list-mode data, passes through the data once only, accounts for finite resolution effects in the system model, and can also include regularization. The algorithm performs multiple image updates during its single pass through the list-mode data, corresponding to the number of subsets that the data have been split into. The algorithm has been assessed using list-mode data from a quad-HIDAC and is compared to the analytic reconstruction method 3-D reprojection (RP) with 3-D filtered backprojection.

This paper presents Markov chain Monte Carlo data association (MCMCDA) for solving data association problems arising in multiple-target tracking in a cluttered environment. When the number of targets is fixed, the single-scan version of MCMCDA approximates joint probabilistic data association (JPDA). Although the exact computation of association probabilities in JPDA is NP-hard, we prove that the single-scan MCMCDA algorithm provides a fully polynomial randomized approximation scheme for JPDA. For general multiple-target tracking problems, in which unknown numbers of targets appear and disappear at random times, we present a multi-scan MCMCDA algorithm that approximates the optimal Bayesian filter. It exhibits remarkable performance compared to multiple hypothesis tracking (MHT) under extreme conditions, such as a large number of targets in a dense environment, low detection probabilities, and high false alarm rates.

High-level actions (HLAs) lie at the heart of hierarchical planning. Typically, an HLA admits multiple refinements into primitive action sequences. Correct descriptions of the effects of HLAs may be essential to their effective use, yet the literature is mostly silent. We propose an angelic semantics for HLAs, the key concept of which is the set of states reachable by some refinement of a high-level plan, representing uncertainty that will ultimately be resolved in the planning agent's own best interest. We describe upper and lower approximations to these reachable sets, and show that the resulting definition of a high-level solution automatically satisfies the upward and downward refinement properties. We define a STRIPS-like notation for such descriptions. A sound and complete hierarchical planning algorithm is given and its computational benefits are demonstrated. This is an extended version of a paper by the same name appearing in ICAPS '07.

We study the criteria under which an object can be gripped by multi-ngered dexterous hand, assuming no static friction between the object and the ngers; such grips are called positive grips. We study three cases in detail: (i) the body is at equilibrium, (ii) the body is under some constant external force/torque, and (iii) the body is under a varying external force/torque. In each case we obtain tight bounds on the number of ngers needed to obtain grip. We also present e cient algorithms to synthesize such positive grips for bounded polyhedral/polygonal objects; the number of ngers employed in the grips synthesized by our algorithms match the above bounds. The algorithms run in time linear in the number of faces/sides.

By Fourier's theorem 1 , signals can be decomposed into a sum of sinusoids of different frequencies. This is especially relevant for hearing, because the inner ear performs a form of mechanical Fourier transform by mapping frequencies along the length of the cochlear partition. An alternative signal decomposition, originated by Hilbert 2 , is to factor a signal into the product of a slowly varying envelope and a rapidly varying fine time structure. Neurons in the auditory brainstem 3 -6 sensitive to these features have been found in mammalian physiological studies. To investigate the relative perceptual importance of envelope and fine structure, we synthesized stimuli that we call 'auditory chimaeras' , which have the envelope of one sound and the fine structure of another. Here we show that the envelope is most important for speech reception, and the fine structure is most important for pitch perception and sound localization. When the two features are in conflict, the sound of speech is heard at a location determined by the fine structure, but the words are identified according to the envelope. This finding reveals a possible acoustic basis for the hypothesized 'what' and 'where' pathways in the auditory cortex 7 -10 .

In this paper, we describe the soccer playing agent developed by our team UT Austin Villa to participate in the RoboCup 3D simulation soccer competition held in Atlanta, U.S.A., in July 2007. The 2007 competition saw the introduction of a humanoid robot in the 3D simulation league. We present an overview of this new version of the simulation league, followed by a description of our approaches in programming the humanoid robot. Our main emphasis was on developing skills such as walking and turning for the humanoid robot.

Named-entity recognition systems extract entities such as people, organizations, and locations from unstructured text. Rather than extract these mentions in isolation, this paper presents a record extraction system that assembles mentions into records (i.e. database tuples). We construct a probabilistic model of the compatibility between field values, then employ graph partitioning algorithms to cluster fields into cohesive records. We also investigate compatibility functions over sets of fields, rather than simply pairs of fields, to examine how higher representational power can impact performance. We apply our techniques to the task of extracting contact records from faculty and student homepages, demonstrating a 53% error reduction over baseline approaches.

Named-entity recognition systems extract entities such as people, organizations, and locations from unstructured text. Rather than extract these mentions in isolation, this paper presents a record extraction system that assembles mentions into records (i.e. database tuples). We construct a probabilistic model of the compatibility between field values, then employ graph partitioning algorithms to cluster fields into cohesive records. We also investigate compatibility functions over sets of fields, rather than simply pairs of fields, to examine how higher representational power can impact performance. We apply our techniques to the task of extracting contact records from faculty and student homepages, demonstrating a 53% error reduction over baseline approaches.

There is a growing consensus that clinical evaluation of the real-world consequences of eye disease requires new performance-based tests. This is because Sueilen acuity and other common clinical tests are often poor predictors of everyday function. Ahn and Legge !(1995) Vision Research, 35, [1931][1932][1933][1934][1935][1936][1937][1938]] validated a computerized test of reading speed by showing that it provides an accurate prediction of low-vision reading performance with magnifiers. Here, we describe development of a printed-card version of the test suitable for clinical use. This printed-card test retains key design features of the validated computerized test, including the same set of sentences and display format. Data from 23 low-vision subjects showed that a very simple testing procedure using printed cards and a stop watch could be used effectively to estimate reading speed. Reading speed based on a single card was quite accurate (SD equal to about 18% of the mean) and showed no practice effects from one card to the next. Reading speeds obtained with printed cards correlated highly (r ----0.887) with those from computerized testing. We conclude that a simple test, using printed cards, can be used to obtain useful estimates of low-vision reading speed.

This is the eighth in a series of papers dealing with the role of vision in reading. In previous papers, we have evaluated the effects of stimulus and subject variables on reading rate using a drifting-text procedure. In this paper, we describe a new test of reading rate that uses static text, called the Minnesota Low-Vision Reading Test (MNread). It is microcomputer-based, and more easily set up and administered than the drifting-text procedure. It is of potential value as a standardized psychophysical test of reading and should be useful in research, clinical, and educational applications. Some types of low-vision aids rely on drifting text and others on static text. Is reading performance different for these two modes of text presentation? We measured reading rate as a function of angular character size for normal and low-vision subjects with drifting and static text. Although reading rates were highly correlated for the two modes of text presentation, normal subjects usually read static text more rapidly. The reverse was true for lowvision subjects; their reading rates for drifting text were slightly higher (average 15%) than for static text.

Fractal functions are explored as a representation for rough data in computer graphics. Two new techniques for using fractal interpolation functions to approximate rough functions and curves are introduced. The first is based on a Hough transform of fractal function transformation parameters. The second is based on previous techniques in fractal image compression. These techniques are then demonstrated on the task of recovering the parameters of a fractal function, approximating a rough function and approximating the boundary of a leaf.

Numerous techniques have been developed to perform advanced shading operations in real time. The real-time versions vary greatly from their original implementations due to the constraints of existing hardware and programming libraries. This paper introduces a grammar for articulating these modern real-time shading pipelines. We survey the existing techniques, using the grammar to classifies them into a taxonomy illustrating the commutations that differentiate the pipelines from the classical version and each other. The taxonomy follows a natural development that concludes with texture shading, which is applied to four advanced shaders to explore its versatility.

An ordered series of control poses may be interpolated by a polyscrew rigid body motion composed of a series of screws, each interpolating a pair of consecutive control poses. The trajectory of each point during screw motion is (C ∞ ). Although a polyscrew is continuous, velocities are typically discontinuous at control poses when the motion switches between screws. We obtain a smooth motion by subdividing the polyscrew. Three subdivision schemes are proposed: the interpolating 4-point subdivision, the smooth cubic B-spline subdivision, and the Jarek subdivision, an average of these two. Their implementation is trivial and their computation sufficiently fast for realtime subdivision and animation, which is particularly important for interactive motion editing and hardware support for animation.

In contrast to machined mechanical parts, the 3D shapes encountered in biomedical or styling applications contain many tubular parts, protrusions, engravings, embossings, folds, and smooth bends. It is difficult to design and edit such features using the parameterized operations or even free-form deformations available in CAD or animation systems. The Bender tool proposed here complements previous solutions by allowing a designer holding a 6 DoF 3D tracker in each hand to control the position and orientation of the ends of a stretchable virtual ribbon, which is used to grab the shape in its vicinity and to deform it in realtime, as the designer continues to move, bend, and twist the ribbon. To ensure realtime performance and intuitive control of the ribbon, we model its centerline as a circular biarc and perform adaptive refinement of the triangle-mesh approximation of the surface. To produce a natural and predictable warp, we use the initial and final shapes of the ribbon to define a one-parameter family of screw-motions. The deformation of a surface point is computed by finding its locally closest projection, or projections, on the biarc and by applying the corresponding screws, weighted by a function that decays with the distance to the projection. The combination of these solutions leads to an easy-to-use and effective tool for the direct manipulation of organic or stylized shapes.

The growing interest in haptic applications suggests that haptic digital media will soon become widely available, and the need will arise to protect digital haptic data from misuse. In this article, we present our study and findings on psychophysical experiments regarding human abilities to perceive a digital watermark, or hidden signal, through a haptic interface.

Traditional supervised learning techniques do not address online learning problems such as concept drift, due to the fact that learning is offline when using these methods. Associative neural networks using Hebbian learning rules show robust performance in classification tasks involving concept drift. Biologically plausible neural networks represent a set of computational models designed to be more strongly related to biological neuron models. In this paper, we apply a biologically inspired plasticity model of synapse dynamics to a concept drift classification problem. The motivation for this method is to provide more biologically plausible networks in cognitive tasks.

This paper summarizes the design and implementation of a parallel algorithm for state assignment of large Finite State Machines (FSMs). High performance CAD tools are necessary to overcome the computational complexity involved in the optimization of large sequential circuits. FSMs constitute an important class of logic circuits, and state assignment is one of the key steps in combinational logic optimization. The SMPbased parallel algorithm -based on the sequential program JEDI targeting multilevel logic implementation -scales nearly linearly with the number of processors for FSMs of varying problem sizes chosen from standard benchmark suites while attaining quality of results comparable to the best sequential algorithms.

Since their debut in 1987, snakes (active contour models) have become a standard image analysis technique with several variants now in common use. We present a framework called ''United Snakes'', which has two key features. First, it unifies the most popular snake variants, including finite difference, B-spline, and Hermite polynomial snakes in a consistent finite element formulation, thus expanding the range of object modeling capabilities within a uniform snake construction process. Second, it embodies the idea that the heretofore presumed competing technique known as ''live wire'' or ''intelligent scissors'' is in fact complementary to snakes and that the two techniques can advantageously be combined by introducing an effective hard constraint mechanism. The United Snakes framework amplifies the efficiency and reproducibility of the component techniques, and it offers more flexible interactive control while further minimizing user interactions. We apply United Snakes to several different medical image analysis tasks, including the segmentation of neuronal dendrites in EM images, dynamic chest image analysis, the quantification of growth plates in MR images and the isolation of the breast region in mammograms, demonstrating the generality, accuracy and robustness of the tool.