2,645 research outputs found
Creeping motion of a solid particle inside a spherical elastic cavity
On the basis of the linear hydrodynamic equations, we present an analytical
theory for the low-Reynolds-number motion of a solid particle moving inside a
larger spherical elastic cavity which can be seen as a model system for a fluid
vesicle. In the particular situation where the particle is concentric with the
cavity, we use the stream function technique to find exact analytical solutions
of the fluid motion equations on both sides of the elastic cavity. In this
particular situation, we find that the solution of the hydrodynamic equations
is solely determined by membrane shear properties and that bending does not
play a role. For an arbitrary position of the solid particle within the
spherical cavity, we employ the image solution technique to compute the
axisymmetric flow field induced by a point force (Stokeslet). We then obtain
analytical expressions of the leading order mobility function describing the
fluid-mediated hydrodynamic interactions between the particle and confining
elastic cavity. In the quasi-steady limit of vanishing frequency, we find that
the particle self-mobility function is higher than that predicted inside a
rigid no-slip cavity. Considering the cavity motion, we find that the
pair-mobility function is determined only by membrane shear properties. Our
analytical predictions are supplemented and validated by fully-resolved
boundary integral simulations where a very good agreement is obtained over the
whole range of applied forcing frequencies.Comment: 15 pages, 5 figures, 90 references. To appear in Eur. Phys. J.
Software Architecture Patterns for a Context-Processing Middleware Framework
International audienceUbiquitous applications are characterised by variations of their execution context. Their correct operation requires some continual adaptations based on the observation of their execution context. The design and the implementation of these observation policies is then the cornerstone of any ubiquitous applications. In this article, we propose COSMOS which is a framework for the principled specification and composition of context observation policies. With COSMOS, these policies are decomposed into fine-grained units called \emph{context nodes} implemented as software components. These units perform basic context-related operations (\emph{e.g.}, gathering data from a system or network probe, computing threshold or average values) and are assembled with a set of well-identified architectural design patterns. In this article, COSMOS is motivated and illustrated with an example from the domain of mobile e-commerce applications
CSP channels for CAN-bus connected embedded control systems
Closed loop control system typically contains multitude of sensors and actuators operated simultaneously. So they are parallel and distributed in its essence. But when mapping this parallelism to software, lot of obstacles concerning multithreading communication and synchronization issues arise. To overcome this problem, the CT kernel/library based on CSP algebra has been developed. This project (TES.5410) is about developing communication extension to the CT library to make it applicable in distributed systems. Since the library is tailored for control systems, properties and requirements of control systems are taken into special consideration. Applicability of existing middleware solutions is examined. A comparison of applicable fieldbus protocols is done in order to determine most suitable ones and CAN fieldbus is chosen to be first fieldbus used. Brief overview of CSP and existing CSP based libraries is given. Middleware architecture is proposed along with few novel ideas
Intelligent Debris Mass Estimation Model for Autonomous Underwater Vehicle
Marine debris poses a significant threat to the survival of marine wildlife,
often leading to entanglement and starvation, ultimately resulting in death.
Therefore, removing debris from the ocean is crucial to restore the natural
balance and allow marine life to thrive. Instance segmentation is an advanced
form of object detection that identifies objects and precisely locates and
separates them, making it an essential tool for autonomous underwater vehicles
(AUVs) to navigate and interact with their underwater environment effectively.
AUVs use image segmentation to analyze images captured by their cameras to
navigate underwater environments. In this paper, we use instance segmentation
to calculate the area of individual objects within an image, we use YOLOV7 in
Roboflow to generate a set of bounding boxes for each object in the image with
a class label and a confidence score for every detection. A segmentation mask
is then created for each object by applying a binary mask to the object's
bounding box. The masks are generated by applying a binary threshold to the
output of a convolutional neural network trained to segment objects from the
background. Finally, refining the segmentation mask for each object is done by
applying post-processing techniques such as morphological operations and
contour detection, to improve the accuracy and quality of the mask. The process
of estimating the area of instance segmentation involves calculating the area
of each segmented instance separately and then summing up the areas of all
instances to obtain the total area. The calculation is carried out using
standard formulas based on the shape of the object, such as rectangles and
circles. In cases where the object is complex, the Monte Carlo method is used
to estimate the area. This method provides a higher degree of accuracy than
traditional methods, especially when using a large number of samples
On using the CAMA framework for developing open mobile fault tolerant agent systems
The paper introduces the Cama (Context-Aware Mobile Agents) framework intended for developing large-scale mobile applications using the agent paradigm. Cama provides a powerful set of abstractions, a supporting middleware and an adaptation layer allowing developers to address the main characteristics of the mobile applications: openness, asynchronous and anonymous communication, fault tolerance, device mobility. It ensures recursive system structuring using location, scope, agent and role abstractions. Cama supports system fault tolerance through exception handling and structured agent coordination. The applicability of the framework is demonstrated using an ambient lecture scenario - the first part of an ongoing work on a series of ambient campus applications
An Analysis of the Creative Style of French New Wave Cinema, Illustrated by Godard’s Film “Breathless”
When delving into the annals of film history, the pivotal juncture of the French New Wave movement in the 1940s stands as an indispensable focal point, leaving an indelible mark on cinematic evolution and the advancement of the film industry. By introducing a distinctive creative paradigm, the movement notably championed the notion of “auteur cinema”, and encouraged novel production methodologies while endorsing personalized themes, distinctive narrative architectures, unique cinematographic aesthetics, and pioneering editing techniques. As a luminary within the constellation of the French New Wave, Jean-Luc Godard orchestrated elaborate and audacious cinematic experiments in the realms of visual and auditory language. Godard dismantled entrenched narrative conventions and cinematic mores of the studio apparatus, thereby clearing a path for a more self-revealing and artistically-inflected cinematic discourse. This cinematic idiom exerted a profound influence not only upon contemporaneous directors but also furnished subsequent generations of cineastes with a wellspring of inspiration.From the vantage point of Godard, this research attempts to explore and synthesize the historical backdrop of the New Wave era, the idiosyncrasies and shared traits of movie auteurs, and analyzed in a meticulous manner of his magnum opus, “Breathless”. This analytical research encompasses editing methodologies, cinematographic modalities, narrative architectures, and proclivities toward expression with the overarching goal of unearthing the unique cinematic lexicon emblematic of the New Wave. Conclusively, this study pivots back to appraise the French New Wave, unraveling its cultural import and historical limitations
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