Smooth Morphing Research Articles

Smooth morphing of immersed spherical curves and application to ruled surfaces

In this paper, we realize a rapid, smooth iterative morphing algorithm between two immersed and closed spherical curves of arbitrary turning numbers. By compensating in turning numbers, we linearly interpolate between geodesic curvatures and the side lengths of their accurate spherical polygons approximation. Our algorithm is essentially based on a geometrical closure condition for a flow of spherical polygons involving the variation of both sides and exterior angles. A curvature smoothing flow using discrete geodesic curvature is adopted for smooth curve generation. To demonstrate the good properties of the method, a morphing of spherical curves and ruled surfaces is illustrated.

A Preliminary Evaluation of Morphing Horizontal Tail Design for UAVs

Morphing structures are a relatively new aircraft technology currently being investigated for a variety of applications, from civil to military. Despite the lack of literature maturity and its complexity, morphing wings offer significant aerodynamic benefits over a wide range of flight conditions, enabling reduced aircraft fuel consumption and airframe noise, longer range and higher efficiency. The aim of this study is to investigate the impact of morphing horizontal tail design on aircraft performance and flight mechanics. This study is conducted on a 1:5 scale model of a Preceptor N-3 Pup at its trim condition, of which the longitudinal dynamics is implemented in MATLAB release 2022. Starting from the original horizontal tail airfoil NACA 0012 with the elevator deflected at the trim value, this is modified by using the X-Foil tool to obtain a smooth morphing airfoil trailing edge shape with the same CLα. By comparing both configurations and their influence on the whole aircraft, the resulting improvements are evaluated in terms of stability in the short-period mode, reduction in the parasitic drag coefficient CD0, and increased endurance at various altitudes.

Morphometry and Molecular Identification of Haemonchus Cobb, 1898 (Trichostrongylidae: Nematoda) Isolates from Small Ruminants in Tanzania Based on Mitochondrial cox 1 and rRNA-ITS genes.

The genus Haemonchus is the major abomasal parasite of ruminants responsible for substantial economic losses in tropical and temperate regions. This study was conducted to clarify the morphometry and molecular characterisation of Haemonchus species isolated from sheep in Babati district, Tanzania. A total of 486 trichostrongylid nematodes were recovered from five sheep. Of the total worms, 106 nematodes were distinguished by 37 males and 69 females. The asymmetrical length of dorsal ray and the distance of bulb at the apex of spicules were used for identification of males. In females, the linguiform vulvar flap was the most predominant with 33 out of 69 (48%) compared with knobbed morph type which was 25/69 (36%) and smooth morph type with 11/69 (16%). Partial cox1 sequence fragments of Haemonchus contortus isolates showed 98.8%, 99.3%, 99.7%, 99.5%, 99.3%, and 98.4% in male, smooth, knobbed, linguiform A, linguiform B, and linguiform C, respectively; with the average nucleotide divergence ranged from 1.03 to 2.35%. The amplified fragments of ITS-2 genes in knobbed, linguiform A, and smooth morphotypes revealed 99.4%, 98.5%, and 98.3%, respectively. Phylogenetic analysis was evaluated by employing Bayesian inference and maximum-likelihood, and the tree was distinctly separated into three clusters focusing on H. contortus in cluster I within the family Haemonchidae. Genetic drifting, mutation, and modification of the morphological features of the Haemonchus species described to have an impact on the development of drug resistance. Species identification is necessary to understand which species infect animal host. We recommend more studies on the parasites intensity and the strategies for controlling Haemonchus species in Tanzania.

Light load analysis and topology morphing between full-/half-bridge DC-to-DC converter

ABSTRACT To retain high efficiency in a wide output voltage range and reduce the conduction and switching losses for a DC power supply, this work makes use of topology morphing between full- and half-bridge converters. The operation of the converter is better as a phase-shift modulated (PSM) full-bridge converter for a high output voltage and as the asymmetrical pulse-width modulated (APWM) half-bridge counterpart for a low output voltage. The light load operations of PSM full-bridge and APWM half-bridge DC converter are analysed in detail to account for the voltage gain variation as well as the switching and conduction losses. A suitable control algorithm is also proposed to facilitate smooth morphing transitions and eliminates the unwanted voltage and current overshoot. A laboratory converter circuit rated at outputs up to 60 V, 1.8 kW with 180 V input voltage is designed and built to verify the operation with topology morphing. The experimental results have demonstrated by adapting the PSM full-bridge DC converter to the APWM half-bridge DC converter at the low voltage range that the circuit efficiency can be effectively improved and enhanced 6% for the best.

High actuation capability and smooth-deformation piezo morphing wing based on multi-layer parallel pre-compressed MFC bimorph

A single macro-fiber composite (MFC) unimorph or bimorph wing can only be applied to micro aerial vehicles (MAV) at speeds lower than 20 m/s owing to its relatively small output work. In this study, a high-actuation MFC pre-compressed bimorph actuator (MFC-PBA) multilayer parallel morphing wing is proposed for application in high-speed miniature unmanned aerial vehicles (mini-UAVs). The morphing wing adopts the proposed ribs with an arc groove and three parallel layers of MFC-PBAs to improve the output work and guarantee smooth morphing wing surface. The large deformation finite element (FE) models of a single MFC-PBA and its multilayer parallel morphing wing are established to evaluate the output deformation and output force. Subsequently, a prototype of the morphing wing is fabricated, and the actuation capabilities of the single MFC-PBAs and morphing wing are tested. The experimental and FE simulation results satisfactorily agree. The results show that at the peak driving voltage, with axial compression forces of 18 and 27 N applied to the side and middle MFC-PBAs, respectively, the deflection angle of the morphing wing reaches ±12°, which is twice that of the morphing wing without compression; and its blocking force is maintained at 1.682 N; thus, its output work has doubled. The multiphysics model of the proposed morphing wing under airflow is established to evaluate the deformation capability. The results show that the present morphing wing achieves a deflection of 5.04° on the side of the incoming flow direction, and a unit lift of 249.1 N/m at an air speed of 40 m/s and angle of attack of 15°. Consequently, the proposed morphing wing exhibits a high deformation capability. We expect the proposed morphing wing will be used for the flight control of mini-UAVs at higher speeds and larger sizes.

Theoretical and experimental investigations on modified LQ terminal control scheme of piezo-actuated compliant structures in finite time

This study focuses on the open-loop dynamic shape control to realize a rapid and smooth morphing process for a flexible plate which is actuated by a macro fiber composite patch. A finite element model of the system is established and verified for theoretical investigations. Steady-state and dynamic analyses are carried out to satisfy the desired rest-to-test morphing requirement. Spurious oscillations and large overshoots are observed while applying some common voltage signals. The results imply that the voltage profile of the actuator plays a key role in the dynamic morphing behavior of the system. Therefore, a quantitative criterion is proposed to determine the critical voltage slope for evaluating the boundary between quasi-static and dynamic processes. An optimal finite-time feedforward control approach named “modified linear quadratic (LQ) terminal controller” is proposed to optimize the voltage profiles by simultaneously considering the suppression of transient and residual vibration. The superiority of the proposed open-loop control scheme is appreciated when it is compared with the standard LQ terminal controller. An experimental setup is designed for verification. The effectiveness of the theoretical model is validated through modal analysis, static deformation, and dynamic responses. It is indicated by the experiment results that rapid and smooth dynamic shape morphing processes with negligible vibration within a short period of time can be achieved using the optimized voltage profile.

OD Morphing: Balancing Simplicity with Faithfulness for OD Bundling

OD bundling is a promising method to identify key origin-destination (OD) patterns, but the bundling can mislead the interpretation of actual trajectories traveled. We present OD Morphing, an interactive OD bundling technique that improves geographical faithfulness to actual trajectories while preserving visual simplicity for OD patterns. OD Morphing iteratively identifies critical waypoints from the actual trajectory network with a min-cut algorithm and transitions OD bundles to pass through the identified waypoints with a smooth morphing method. Furthermore, we extend OD Morphing to support bundling at interaction speeds to enable users to interactively transition between degrees of faithfulness to aid sensemaking. We introduce metrics for faithfulness and simplicity to evaluate their trade-off achieved by OD morphed bundling. We demonstrate OD Morphing on real-world city-scale taxi trajectory and USA domestic planned flight datasets.

Dynamic shape control of piezocomposite-actuated morphing wings with vibration suppression

Aerodynamic properties and aeroelastic responses of morphing wings can be improved via active shape control using piezoelectric actuators. In this article, a type of piezocomposite material called macro-fiber composite is used for actuation to achieve shape control of the morphing wing. This study focuses on the vibration suppression of the wing during dynamic morphing motion in open-loop architecture. The aeroelastic model is established using finite element method and Theodorsen unsteady aerodynamic loads. Because the arbitrary selection of any admissible control voltage profiles will cause vibrations of the wing structure and fluctuations in aerodynamic lift, a dynamic shape control approach is presented to optimize the voltage profiles for the actuators. A proof-of-concept simulation is presented for a scaled high-aspect-ratio wing. The results show that continuous, smooth morphing motion with gentle aeroelastic responses can be realized by applying the optimum voltage profiles. The dynamic shape control performance of the morphing wing can be improved compared with step and ramp voltage profiles.

Documenting domestication in a lost crop (Polygonum erectum L.): evolutionary bet-hedgers under cultivation

This study uses morphometrics and digital image analysis to document domestication syndrome in an annual seed crop, Polygonum erectum L. (erect knotweed), which was cultivated by Native Americans for c. 2,500 years in eastern North America. This plant is one of several seed crops referred to as the Eastern Agricultural Complex, a pre-maize agricultural system that supported societies in a core area centred on the central Mississippi valley for millennia. The extinct domesticated subspecies P. erectum ssp. watsoniae N. G. Muell. described here, exhibits some classic markers of domestication, including larger fruits and reduced germination inhibitors in comparison to its wild progenitor. Domesticated P. erectum also exhibits greatly reduced germination heteromorphism. Germination heteromorphism is the classic example of evolutionary bet-hedging in plants: wild P. erectum sacrifices maximum fitness per generation for a reduction in fitness variance over many generations. It does so by producing two different types of fruits: ones that germinate immediately in the spring after they are produced (smooth morphs), and ones that remain in the soil seed bank for one or more growing seasons before germinating (tubercled morphs). Tubercled morphs allow populations to recover after adverse events. Under cultivation, the selective pressures that maintained this strategy were relaxed as humans saved seeds and created predictable microenvironments for seedlings, resulting in homogenous harvests and reliable germination for ancient farmers.

CaRo 2.0: An Interactive System for Expressive Music Rendering

In several application contexts in multimedia field (educational, extreme gaming), the interaction with the user requests that system is able to render music in expressive way. The expressiveness is the added value of a performance and is part of the reason that music is interesting to listen. Understanding and modeling expressive content communication is important for many engineering applications in information technology (e.g., Music Information Retrieval, as well as several applications in the affective computing field). In this paper, we present an original approach to modify the expressive content of a performance in a gradual way, applying a smooth morphing among performances with different expressive content in order to adapt the audio expressive character to the user’s desires. The system won the final stage of Rencon 2011. This performance RENdering CONtest is a research project that organizes contests for computer systems generating expressive musical performances.

Multidisciplinary parameterization study-based control-centric idea for hypersonic morphing vehicle

The design problems using multidisciplinary parameterization methods for a hypersonic morphing vehicle are investigated in this paper. First, the non-linear model of the hypersonic morphing vehicle in line with the parameterized process is established by combining with the different disciplines. Then, the waverider performances determined by the static and dynamic properties are discussed by application of the multidisciplinary design ideas. Afterwards, the optimal results considering the anticipated performance criteria are acquired by multidisciplinary optimization. Furthermore, the switching control system is designed for hypersonic morphing vehicle to implement the smooth morphing process and to guarantee the overall stability. Finally, the proposed methods are verified by a numerical example, and the resulting simulation shows that waveriding performance can be enhanced as the hypersonic vehicle is designed as a morphing shape.

The Inheritance of Intrasexual Dimorphism in Female Diving Beetles (Coleoptera: Dytiscidae)

Many species of Dytiscus diving beetles exhibit intrasexual dimorphism, e.g., the elytra is smooth in some females and grooved in others. However, the expression of the grooves and whether they are a product of heredity or the environment remain unknown. One Japanese species, Dytiscus sharpi sharpi Wehncke, 1875 , also shows female dimorphism, with grooved and smooth morphs, while D. sharpi validus Régimbart, 1899, only has a single morph (the grooved type). A hybrid of the two species should therefore provide a means of sorting out how the grooves are inherited. We found two independent wetlands of D. sharpi sharpi in Chiba Prefecture, Japan. One was a place where a high proportion of grooved females lived, and the others had high proportions of smooth females. After five to eight generations of beetles from two populations with different proportions of grooved females were reared under aquarium conditions constituting a common garden design, i.e., water temperature, water depth, and presence of a plant for oviposition, the differences remained. We mated smooth virgin females of D. sharpi sharpi with males of D. sharpi validus to obtain hybrid offspring. The elytral traits of the hybrid females produced only grooved forms. These results suggested that the female dimorphism is determined by genetics, and that the grooved morph was dominant over the smooth one, independent of environmental factors. In addition, the hybrid insects did not differ from the two subspecies insects in larval survivorship, pupation success, or sex ratio. They also showed neither morphological abnormality nor reduced survival.

A novel terrain rendering algorithm based on quasi Delaunay triangulation

Terrain rendering has long been an interesting research topic, and Delaunay triangulation has been one of the methods frequently employed. The problem of smooth morphing between successive Delaunay meshes in a dynamic setting does not have a satisfactory solution however. In this paper, we address this issue by temporarily relieving the mesh from the strict constraints of Delaunay triangulation (DT). The proposed algorithm uses an off-line process to compute a relative importance for each sampling point in a Digital Elevation Model (DEM). It then constructs a mesh model in real-time from a set of points selected according to their viewpoint distances and relative importances. The mesh model is initialized to be a genuine DT. As the viewpoint moves, some points are added, and some are removed. We use simple methods for point insertion and removal that allow smooth morphing between successive frames. While the simple methods do not ensure Delaunay properties, we eliminate the slivery triangles gradually by collecting and flipping illegal edges incident to them. Point insertions, removals, edge flips, and their animations are organized by queueing and carried out over time. In this way, we amortize the burst computations to successive frames, so that a balanced workload and a high frame rate are achieved. The proposed algorithm produces a concise and well-composed mesh adaptive to both viewpoint and the terrain’s local geometry, and, most importantly, it supports smooth morphing.

Spatiotemporal separation of New Zealand mudsnails from predatory fish

The use of subsurface sediments by benthic prey as spatial refugia from predators can potentially influence predator consumption, and hence density-dependent relationships. We studied how predatory fish affect subsurface sediment use by spiny- and smooth-shelled morphs of the mudsnail, Potamopyrgus antipodarum, on New Zealand’s South Island. Spines reduce consumption risk by small benthic fishes (e.g., bullies [Gobiomorphus spp.]). Thus, we predicted that spiny morphs would be more likely to use sediment surfaces with relatively high algal food supplies than the more vulnerable smooth morphs when exposed to fish predators. Epi- and endobenthic samples from 5 streams with fish showed that ∼80% of snails typically were retrieved from subsurface sediments, whereas only 33% of snails from fishless Jackson’s Creek occurred in subsurface sediments. A laboratory experiment revealed that significantly more snails used subsurface sediments when with common bullies (G. cotidianus) than when without. Subsurface sediment use in the presence of bullies was similar between shell morphs, a result suggesting that use of spatial refugia might be a more important predator defense than shell armature for Potamopyrgus. Regardless of fish presence, more spiny than smooth morphs burrowed into sand, but subsurface use did not differ between shell morphs in cobbles and gravel. Fewer snails were active on rock surfaces at night than during the day in a stream run, apparently to reduce encounters with nocturnally hunting bullies and shortfinned eels (Anguilla australis). Our results suggest that if fish predation pressure were reduced, then surface densities of Potamopyrgus would increase significantly. Given the snail’s superior competitive abilities, this increase could alter top-down and bottom-up effects in food chains and threaten local biodiversity.

Optimal Design of Compliant Trailing Edge for Shape Changing

Adaptive wings have long used smooth morphing technique of compliant leading and trailing edge to improve their aerodynamic characteristics. This paper introduces a systematic approach to design compliant structures to carry out required shape changes under distributed pressure loads. In order to minimize the deviation of the deformed shape from the target shape, this method uses MATLAB and ANSYS to optimize the distributed compliant mechanisms by way of the ground approach and genetic algorithm (GA) to remove the elements possessive of very low stresses. In the optimization process, many factors should be considered such as airloads, input displacements, and geometric nonlinearities. Direct search method is used to locally optimize the dimension and input displacement after the GA optimization. The resultant structure could make its shape change from 0 to 9.3 degrees. The experimental data of the model confirms the feasibility of this approach.

Abomasal nematodes of sheep and goats slaughtered in Awassa (Ethiopia): species composition, prevalence and vulvar morphology

Abstract A study was carried out to determine the prevalence of abomasal nematodes of sheep and goats slaughtered in Awassa town from January 2006 through June 2006 with special emphasis given to Haemonchus spp. and to characterize vulvar morphs of female Haemonchus worms. During the study period 180 abomasa of sheep and 132 abomasa of goats were examined. Three genera of nematodes were identified in both sheep and goats abomasa with overall prevalence of 91.1 % and 87.1 % respectively. The specific prevalence rates observed were 81.1 % for Haemonchus spp., 47.2 % for Trichostrongylus axei, and 19.4 % for Teladorsagia spp. in sheep and 76.5 % for Haemonchus spp., 39.4 % for T. axei and 20.5 % for Teladorsagia spp. in goats. Out of 653 female Haemonchus recovered from sheep, 37.8 % had a linguiform vulvar flap, 30 % knobbed and 35.4 % smooth vulvar morphs. Out of 448 female Haemonchus recovered from goats, 43.8 % had linguiform vulvar flaps, 27.2 % knobbed and 29 % smooth morph type. A total of 239 linguiform female Haemonchus from sheep were further classified in to 15.1 % linguiform A (LA), 17.5 % linguiform B (LB), 39.7 % linguiform C (LC) and 27.6 % linguiform I (LI) and similarly from goats 196 linguiform female Haemonchus were further classified into 11.2 % LA, 12.2 % LB, 44.9 % LC and 31.6 % LI. Similar findings were observed in both host species regarding the worm burden, prevalence of infection and morphological pattern of Haemonchus species. Generally a high infection rate with abomasal nematodes was observed in both sheep and goats of the study area.

HABITAT-SPECIFIC VARIATION AND PERFORMANCE TRADE-OFFS IN SHELL ARMATURE OF NEW ZEALAND MUDSNAILS

Studies documenting phenotypic variation among populations show that ecological performance in one activity is sometimes traded off against another. Identifying environment-specific costs and benefits associated with performance trade-offs is fundamental to knowing how conflicting selection pressures shape phenotype-environment matching in populations. We studied phenotypic variation in shell armature (spininess) of the New Zealand mudsnail, Potamopyrgus antipodarum (Gray), and explored how this variability relates to performance trade-offs between flow resistance and predator deterrence. Smooth- and spiny-shell morphotypes exist in populations in New Zealand streams and lakes, but the patterns and correlates of spatial variation of these phenotypes, and the possible hydrodynamical constraints and antipredatory benefits associated with spiny shell armature, are unknown. Samples from 11 rivers and nine lakes on the South Island showed that, on average, nearly 70% of snails in streams were smooth-shelled, whereas >80% of snails in lakes were spiny, suggesting dissimilar selective pressures between habitats. A laboratory flume experiment revealed that spines collected seston (i.e., suspended algae) at current speeds <40 cm/s, making spiny morphs more prone to flow-induced dislodgment than smooth morphs. However, a fish feeding experiment showed that one benefit of spines on shells was a decrease in predation risk from the common bully (Gobiomorphus cotidianus), a widespread predator of mudsnails in both streams and lakes. All snails egested by bullies were dead, further suggesting that these fishes may exert strong lethal effects on mudsnail populations in nature. Spine expression in lakes also appeared to be temperature related. We conclude that functional trade-offs between risk of flow-induced dislodgment and risk of fish predation affect shell armature frequencies of Potamopyrgus in freshwater habitats.

Video metamorphosis using dense flow fields

AbstractWhen we perform video metamorphosis, it would be desirable to make smooth morphing transitions simultaneously along with the original motion in the image sequences. In this paper, we present a novel semi‐automatic video morphing technique that exhibits this behavior. Our technique effectively exploits temporal coherence and automatic image matching. One‐to‐one dense mappings between pairs of corresponding frames are obtained by applying a compositing procedure and a hierarchical image matching technique. These dense mappings can be initialized with sparse frame‐to‐frame feature correspondences obtained semi‐automatically by integrating a friendly user interface with a robust feature tracking algorithm. Experimental results show that our approach to video metamorphosis can produce superior results. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Modeling and Control of Expressiveness in Music Performance

Expression is an important aspect of music performance. It is the added value of a performance and is part of the reason that music is interesting to listen to and sounds alive. Understanding and modeling expressive content communication is important for many engineering applications in information technology. For example, in multimedia products, textual information is enriched by means of graphical and audio objects. In this paper, we present an original approach to modify the expressive content of a performance in a gradual way, both at the symbolic and signal levels. To this purpose, we discuss a model that applies a smooth morphing among performances with different expressive content, adapting the audio expressive character to the user's desires. Morphing can be realized with a wide range of graduality (from abrupt to very smooth), allowing adaptation of the system to different situations. The sound rendering is obtained by interfacing the expressiveness model with a dedicated postprocessing environment, which allows for the transformation of the event cues. The processing is based on the organized control of basic audio effects. Among the basic effects used, an original method for the spectral processing of audio is introduced.

Controllable morphing of compatible planar triangulations

Two planar triangulations with a correspondence between the pair of vertex sets are compatible ( isomorphic ) if they are topologically equivalent. This work describes methods for morphing compatible planar triangulations with identical convex boundaries in a manner that guarantees compatibility throughout the morph. These methods are based on a fundamental representation of a planar triangulation as a matrix that unambiguously describes the triangulation. Morphing the triangulations corresponds to interpolations between these matrices.We show that this basic approach can be extended to obtain better control over the morph, resulting in valid morphs with various natural properties. Two schemes, which generate the linear trajectory morph if it is valid, or a morph with trajectories close to linear otherwise, are presented. An efficient method for verification of validity of the linear trajectory morph between two triangulations is proposed. We also demonstrate how to obtain a morph with a natural evolution of triangle areas and how to find a smooth morph through a given intermediate triangulation.