Performance Enhancement in Multicore Fiber Using Trench Assisted Technique

Analysis of crosstalk in multicore fiber using trench assisted technique. To reduce the crosstalk between the cores in the fiber the coupled mode theory and coupled power theory are adopted for crosstalk estimation and considering different design parameters such as core pitch, bending radius and wavelength to optimize the crosstalk performance. The homogeneous fiber which works under single mode operation has been considered. The study of performance by varying the trench width is also analysed. Crosstalk variation in outer cores and center core of the fiber is studied. And the study of variation of crosstalk with 5 different core radius has been done. The numerical simulation results of crosstalk behavior over bending radius, wavelength and trench width is obtained.

A Cable Length Invariant Robotic Tail Using a Circular Shape Universal Joint Mechanism

This paper presents the development of a new robotic tail based on a novel cable-driven universal joint mechanism. The novel joint mechanism is synthesized by geometric reasoning to achieve the desired cable length invariance property, wherein the mechanism maintains a constant length for the driving cables under universal rotation. This feature is preferable because it allows for the bidirectional pulling of the cables which reduces the requisite number of actuators. After obtaining this new joint mechanism, a serpentine robotic tail with fewer actuators, simpler controls, and a more robust structure is designed and integrated. The new tail includes two independent macro segments (2 degrees of freedom each) to generate more complex shapes (4 degrees of freedom total), which helps with improving the dexterity and versatility of the robot. In addition, the pitch bending and yaw bending of the tail are decoupled due to the perpendicular joint axes. The kinematic modeling, dynamic modeling, and workspace analysis are then explained for the new robotic tail. Three experiments focusing on statics, dynamics, and dexterity are conducted to validate the mechanism and evaluate the new robotic tail's performance.

What Makes an Instrument Sound Sad? Commentary on Huron, Anderson, and Shanahan

Huron, Anderson, and Shanahan investigated the hypothesis that instruments that are deemed most capable of expressing sadness would also be judged better able to generate acoustic features similar to those used to convey sadness in speech. The judgments of these acoustic features accounted for approximately half (51.3%) of the variance in the judgments of <em>sadness capacity</em>. I argue that the relatively low explanation rate may be partly explained by choices made in the operationalization of the acoustic features, the overlap and relatedness of three of the acoustic features used (<em>mumbling, dark timbre, </em>and<em> lowest pitch</em>), as well as the practical omission of such a significant feature as legato articulation. Furthermore, the method used by Huron and colleagues may have inflated the effect of cultural conceptions on the judgments of <em>sadness capacity. </em>I also argue that <em>low energy</em> &ndash; albeit a fundamental feature of sadness as an emotion &ndash; is not the meaningful factor underlying the set of acoustic features most correlated with <em>sadness capacity. </em>Instead, I suggest that the only acoustic variable significantly predicting evaluations of <em>sadness capacity</em> &ndash; <em>pitch-bending &ndash; </em>best reflected an instrument&rsquo;s capability to manipulate timbre, pitch, loudness and articulation in ways that match and exaggerate the features of sad vocal expression.

Note on the swimming of an elongated body in a non-uniform flow

This paper presents an extension of Lighthill’s large-amplitude elongated-body theory of fish locomotion which enables the effects of an external weakly non-uniform potential flow to be taken into account. To do so, the body is modelled as a Kirchhoff beam, made up of elliptical cross-sections whose size may vary along the body, undergoing prescribed deformations consisting of yaw and pitch bending. The fluid velocity potential is decomposed into two parts corresponding to the unperturbed potential flow, which is assumed to be known, and to the perturbation flow. The Laplace equation and the corresponding Neumann’s boundary conditions governing the perturbation velocity potential are expressed in terms of curvilinear coordinates which follow the body during its motion, thus allowing the boundary of the body to be considered as a fixed surface. Equations are simplified according to the slenderness of the body and the weakness of the non-uniformity of the unperturbed flow. These simplifications allow the pressure acting on the body to be determined analytically using the classical Bernoulli equation, which is then integrated over the body. The model is finally used to investigate the passive and the active swimming of a fish in a Kármán vortex street.