scholarly journals Modelling, Analysis, and Optimization of Three-Dimensional Restricted Visual Field Metric-Free Swarms

2021 ◽  
Author(s):  
Qing Li ◽  
Lingwei Zhang ◽  
Yongnan Jia ◽  
Tianzhao Lu
Keyword(s):  
Visual Field ◽  
Population Size ◽  
Collective Intelligence ◽  
Three Dimensional ◽  
Analysis Data ◽  
Research Field ◽  
External Information ◽  
Single Individual ◽  
Modelling Analysis ◽  
Cohesive Group

Models of collective behaviour have been proved helpful in revealing what mechanism may underlie characteristics of a flock of birds, a school of fish, and a swarm of herds. Recently, the metric-free model gradually occupies a dominant position in the research field of collective intelligence. Most of these models endow every single individual with the ability of a global visual field, which can offer each particle sufficient external information. In this paper, we mainly focus on whether the global visual field is necessary to form a consistent and cohesive group or not. Inspired by the biological characteristic of starlings, we develop a three-dimensional restricted visual field metric-free(RVFMF) model based on Pearce and Turner's previous work. We further investigate several vital factors governing the convergent consistency of the RVFMF model with the assistance of extensive numerical simulations. According to the simulation results, we conclude that the best view angle of each particle in a swarm increases with the expansion of the population size. Besides, the best view angle gradually becomes stable around 155 degrees when the population size is larger than 1000. We also offer quantitative analysis data to prove that a flock of birds could obtain better consistency under optimal restricted visual field than under global visual field.

Inhibition of return at different eccentricities in visual field under three-dimensional (3D) world

2017 ◽  
Vol 49 (6) ◽  
pp. 723
Author(s):  
Aijun WANG ◽  
Xiaole LIU ◽  
Xiaoyu TANG ◽  
Ming ZHANG
Keyword(s):  
Visual Field ◽  
Inhibition Of Return ◽  
Three Dimensional

scholarly journals Collaborative Pursuit-Evasion Strategy of UAV/UGV Heterogeneous System in Complex Three-Dimensional Polygonal Environment

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiao Liang ◽  
Honglun Wang ◽  
Haitao Luo
Keyword(s):  
Visual Field ◽  
Heterogeneous System ◽  
Three Dimensional ◽  
Unmanned Ground Vehicle ◽  
Worst Case ◽  
Ground Vehicle ◽  
Pursuit Evasion ◽  
Evasion Game ◽  
Evasion Strategy ◽  
Aerial Vehicle

The UAV/UGV heterogeneous system combines the air superiority of UAV (unmanned aerial vehicle) and the ground superiority of UGV (unmanned ground vehicle). The system can complete a series of complex tasks and one of them is pursuit-evasion decision, so a collaborative strategy of UAV/UGV heterogeneous system is proposed to derive a pursuit-evasion game in complex three-dimensional (3D) polygonal environment, which is large enough but with boundary. Firstly, the system and task hypothesis are introduced. Then, an improved boundary value problem (BVP) is used to unify the terrain data of decision and path planning. Under the condition that the evader knows the position of collaborative pursuers at any time but pursuers just have a line-of-sight view, a worst case is analyzed and the strategy between the evader and pursuers is studied. According to the state of evader, the strategy of collaborative pursuers is discussed in three situations: evader is in the visual field of pursuers, evader just disappears from the visual field of pursuers, and the position of evader is completely unknown to pursuers. The simulation results show that the strategy does not guarantee that the pursuers will win the game in complex 3D polygonal environment, but it is optimal in the worst case.

scholarly journals Cloning, post-translational modifications, heterologous expression and ligand-binding of boar salivary lipocalin

2000 ◽  
Vol 350 (2) ◽  
pp. 369-379 ◽  
Author(s):  
Dietrich LOEBEL ◽  
Andrea SCALONI ◽  
Sara PAOLINI ◽  
Carlo FINI ◽  
Lino FERRARA ◽  
...  
Keyword(s):  
Amino Acid ◽  
Sequence Similarity ◽  
Three Dimensional ◽  
Protein Isoforms ◽  
Cysteine Residues ◽  
Protein Chemistry ◽  
Single Individual ◽  
Amino Acid Residues ◽  
Three Dimensional Model ◽  
Submaxillary Glands

Boar submaxillary glands produce the sex-specific salivary lipocalin (SAL), which binds steroidal sex pheromones as endogenous ligands. The cDNA encoding SAL was cloned and sequenced. From a single individual, two protein isoforms, differing in three amino acid residues, were purified and structurally characterized by a combined Edman degradation/MS approach. These experiments ascertained that the mature polypeptide is composed of 168 amino acid residues, that one of the three putative glycosylation sites is post-translationally modified and the structure of the bound glycosidic moieties. Two of the cysteine residues are paired together in a disulphide bridge, whereas the remaining two occur as free thiols. SAL bears sequence similarity to other lipocalins; on this basis, a three-dimensional model of the protein has been built. A SAL isoform was expressed in Escherichiacoli in good yields. Protein chemistry and CD experiments verified that the recombinant product shows the same redox state at the cysteine residues and that the same conformation is observed as in the natural protein, thus suggesting similar folding. Binding experiments on natural and recombinant SAL were performed with the fluorescent probe 1-aminoanthracene, which was efficiently displaced by the steroidal sex pheromone, as well as by several odorants.

scholarly journals Three-dimensional Sonography in the Assessment of Normal Fetal Anatomy in Late Pregnancy

2010 ◽  
Vol 4 (3) ◽  
pp. 217-231
Author(s):  
Badreldeen Ahmed ◽  
Ulrich Honemeyer
Keyword(s):  
Continuous Wave ◽  
Power Doppler ◽  
Three Dimensional ◽  
Late Pregnancy ◽  
Research Field ◽  
Surface Rendering ◽  
Volume Data ◽  
Data Set ◽  
3D Volume ◽  
Color And Power Doppler

Abstract Three-dimensional, multiplanar sonography, using a volume data set acquired with a 3D probe, has revolutionized ultrasonographic imaging and takes sonographers to a new perception of the fetus in 3 dimensions. Real time scanning, until the late nineties only possible in B-mode, can now be performed in 3D with up to 40 frames/sec. Fetal neurology emerged as a new perinatal research field with the 4D visualization of fetal behavior. Doppler ultrasound, diversified and refined from continuous wave and pulsed Doppler to Color – and Power Doppler, when added to 3D sonography, creates fascinating options of noninvasive fetal vascular mapping (sonoangiography) and vascular assessment of placenta. The diagnostic and demonstrative potential of an acquired 3D volume data set can be maxed with the help of postprocessing and rendering software. After storage, the evaluation of fetal 3D data sets can happen without the patient, with the option of specialist consultation, using telemedicine. In the article, the new 3D “modes” like surface rendering, maximum mode, 3D Color and Power Doppler, STIC, volume rendering, and glass body rendering, are described and illustrated in their display of normal fetal anatomy.

3D Structural Bioinformatics of Proteins and Antibodies: State of the Art Perspectives and Challenges

2013 ◽  
Vol 2 (3) ◽  
pp. 67-74
Author(s):  
Arianna Filntisi ◽  
Dimitrios Vlachakis ◽  
George Matsopoulos ◽  
Sophia Kossida
Keyword(s):  
Quantum Mechanics ◽  
Quantum Chemical ◽  
State Of The Art ◽  
Three Dimensional ◽  
Research Field ◽  
Important Class ◽  
Structural Components ◽  
Molecular Systems ◽  
Mechanical Methods ◽  
Harmful Substances

Proteins are an important class of biochemical molecules, as the structural components of animal and human tissue are based on them. Antibodies are proteins that play a crucial role in the preservation of life since they are produced by the body's immune system as a response to harmful substances. The modelling of proteins and antibodies in particular is a vibrant research field which facilitates the design of drugs, a process otherwise demanding in terms of time and resources. A variety of computational methods and tools are being developed towards that goal, among which are hybrid quantum chemical/molecular mechanical methods and three-dimensional antibody modelling. In this review the authors discuss the knowledge concerning proteins and antibodies, as well as the use of quantum mechanics in the simulation of molecular systems and the three-dimensional antibody modelling.

Automatic Quality Assessment for Internet Pages

2011 ◽  
pp. 104-112
Author(s):  
Thomas Mandl
Keyword(s):  
Quality Assessment ◽  
Information Overload ◽  
Quality Criteria ◽  
Research Field ◽  
External Information ◽  
Web Page ◽  
Internet Resources ◽  
Systems Learning ◽  
Information Work ◽  
New Research

Automatic quality assessment of Web pages needs to complement human information work in the current situation of an information overload. Several systems for this task have been developed and evaluated. Automatic quality assessments are most often based on the features of a Web page itself or on external information. Promising results have been achieved by systems learning to associate human judgments with Web page features. Automatic evaluation of Internet resources according to various quality criteria is a new research field emerging from several disciplines. This chapter presents the most prominent systems and prototypes implemented so far and analyzes the knowledge sources exploited for these approaches.

scholarly journals Methodological insights on measurement and evaluation of compulsive buying behavior among young consumers in Poland: the case of compulsive- and non-compulsive buyers

2020 ◽  
Author(s):  
Piotr Tarka ◽  
Jasurbek Babaev
Keyword(s):  
Consumer Research ◽  
Latent Variables ◽  
Three Dimensional ◽  
Reliability And Validity ◽  
Compulsive Buying ◽  
Analysis Data ◽  
Dimensional Structure ◽  
Research Association ◽  
Young Consumers ◽  
Measurement And Evaluation

AbstractIn this study we focused on the methodological insights, the measurement and evaluation of compulsive buying tendencies among young consumers in Poland. We administered the Compulsive Buying Scale (CBS) developed by d’Astous et al. (in: Goldberg, Gorn, Pollay (eds) Advances in consumer research, Association for Consumer Research, Provo, 1990) for North America and adapted it to the Polish population. Then used the data to develop a Polish version of the Compulsive Buying Scale (P-CBS). The study extended previous methodological work on new consumers’ culture, and more importantly, investigated the compulsive buying in two groups of consumers: compulsive- and non-compulsive buyers. The sample comprised 504 young Polish citizens, aged between 17 and 25 years. In the complex analytical process, we replicated the three-dimensional structure of the CBS scale (d'Astous et al. 1990): the ‘Tendency to Spend’, a 'Reactive Aspect' of compulsive buying, and 'Post Purchase Guilt'. This process included the following steps: the translation of the items, an exploratory and confirmatory factor analysis, based on latent variables theory, and a reliability and validity analysis. Data analyses indicated a satisfactory reliability and validity of the P-CBS. Research findings are presented across the sample and the subsamples of compulsive buyers and non-compulsive buyers.

Quick phases control ocular torsion during smooth pursuit

2011 ◽  
Vol 106 (5) ◽  
pp. 2151-2166 ◽  
Author(s):  
Bernhard J. M. Hess ◽  
Jakob S. Thomassen
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Oculomotor Control ◽  
Visually Guided ◽  
Open Questions ◽  
Spatial Frequencies ◽  
Eye Rotation ◽  
Smooth Tracking

One of the open questions in oculomotor control of visually guided eye movements is whether it is possible to smoothly track a target along a curvilinear path across the visual field without changing the torsional stance of the eye. We show in an experimental study of three-dimensional eye movements in subhuman primates ( Macaca mulatta) that although the pursuit system is able to smoothly change the orbital orientation of the eye's rotation axis, the smooth ocular motion was interrupted every few hundred milliseconds by a small quick phase with amplitude <1.5° while the animal tracked a target along a circle or ellipse. Specifically, during circular pursuit of targets moving at different angular eccentricities (5°, 10°, and 15°) relative to straight ahead at spatial frequencies of 0.067 and 0.1 Hz, the torsional amplitude of the intervening quick phases was typically around 1° or smaller and changed direction for clockwise vs. counterclockwise tracking. Reverse computations of the eye rotation based on the recorded angular eye velocity showed that the quick phases facilitate the overall control of ocular orientation in the roll plane, thereby minimizing torsional disturbances of the visual field. On the basis of a detailed kinematic analysis, we suggest that quick phases during curvilinear smooth tracking serve to minimize deviations from Donders' law, which are inevitable due to the spherical configuration space of smooth eye movements.

Responses of the teleostean nucleus isthmi to looming objects and other moving stimuli

2006 ◽  
Vol 23 (2) ◽  
pp. 209-219 ◽  
Author(s):  
SHAWN P. GALLAGHER ◽  
DAVID P.M. NORTHMORE
Keyword(s):  
Visual Field ◽  
Neural Activity ◽  
Three Dimensional ◽  
Object Motion ◽  
Activity Levels ◽  
Nucleus Isthmi ◽  
Spike Density ◽  
Ball Size ◽  
Longitudinal Body Axis ◽  
The Right

Visually evoked extracellular neural activity was recorded from the nucleus isthmi (NI) of goldfish and bluegill sunfish. When moving anywhere within the right eye's visual field, three-dimensional checkered balls or patterns on a computer screen evoked bursts of spikes in the left NI. Object motion parallel to the longitudinal body axis gave responses that habituated markedly upon repetition, but movement into recently unstimulated regions of the visual field gave vigorous responses. Thus, while NI's response is not visuotopic, its habituation is. An object approaching the animal's body generated a rising spike density, whereas object recession generated only a transient burst. During the approach of a checkered stimulus ball, average NI spike density rose linearly as the ball-to-eye distance decreased and at a rate proportional to the ball's speed (2.5–30 cm/s). Increasing ball size (2.2–9.2 cm) did not affect the rate of activity rise at a given speed, but did increase overall activity levels. NI also responded reliably to expanding textures of fixed overall size. The results suggest that NI signals changes in motion of objects relative to the fish, and estimates the proximity of approaching objects.

scholarly journals 3D Culture as a Clinically Relevant Model for Personalized Medicine

2017 ◽  
Vol 22 (3) ◽  
pp. 245-253 ◽  
Author(s):  
Eliza Li Shan Fong ◽  
Tan Boon Toh ◽  
Hanry Yu ◽  
Edward Kai-Hua Chow
Keyword(s):  
Cancer Research ◽  
Drug Development ◽  
Cancer Patients ◽  
Cancer Progression ◽  
Three Dimensional ◽  
3D Culture ◽  
Research Field ◽  
Cancer Drug ◽  
Specific Patient ◽  
Culture Systems

Advances in understanding many of the fundamental mechanisms of cancer progression have led to the development of molecular targeted therapies. While molecular targeted therapeutics continue to improve the outcome for cancer patients, tumor heterogeneity among patients, as well as intratumoral heterogeneity, limits the efficacy of these drugs to specific patient subtypes, as well as contributes to relapse. Thus, there is a need for a more personalized approach toward drug development and diagnosis that takes into account the diversity of cancer patients, as well as the complex milieu of tumor cells within a single patient. Three-dimensional (3D) culture systems paired with patient-derived xenografts or patient-derived organoids may provide a more clinically relevant system to address issues presented by personalized or precision medical approaches. In this review, we cover the current methods available for applying 3D culture systems toward personalized cancer research and drug development, as well as key challenges that must be addressed in order to fully realize the potential of 3D patient-derived culture systems for cancer drug development. Greater implementation of 3D patient-derived culture systems in the cancer research field should accelerate the development of truly personalized medical therapies for cancer patients.

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