Online Estimation of Evolving Human Visual Interest

Regions in video streams attracting human interest contribute significantly to human understanding of the video. Being able to predict salient and informative Regions of Interest (ROIs) through a sequence of eye movements is a challenging problem. Applications such as content-aware retargeting of videos to different aspect ratios while preserving informative regions and smart insertion of dialog (closed-caption text) into the video stream can significantly be improved using the predicted ROIs. We propose an interactive human-in-the-loop framework to model eye movements and predict visual saliency into yet-unseen frames. Eye tracking and video content are used to model visual attention in a manner that accounts for important eye-gaze characteristics such as temporal discontinuities due to sudden eye movements, noise, and behavioral artifacts. A novel statistical-and algorithm-based method gaze buffering is proposed for eye-gaze analysis and its fusion with content-based features. Our robust saliency prediction is instantiated for two challenging and exciting applications. The first application alters video aspect ratios on-the-fly using content-aware video retargeting, thus making them suitable for a variety of display sizes. The second application dynamically localizes active speakers and places dialog captions on-the-fly in the video stream. Our method ensures that dialogs are faithful to active speaker locations and do not interfere with salient content in the video stream. Our framework naturally accommodates personalisation of the application to suit biases and preferences of individual users.

Species-area and species-individual relationships for tropical trees: A comparison of three 50-ha plots

1 Species-accumulation curves for woody plants were calculated in three tropical forests, based on fully mapped 50-ha plots in wet, old-growth forest in Peninsular Malaysia, in moist, old-growth forest in central Panama, and in dry, previously logged forest in southern India. A total of 610 000 stems were identified to species and mapped to < Im accuracy. Mean species number and stem number were calculated in quadrats as small as 5 m x 5 m to as large as 1000 m x 500 m, for a variety of stem sizes above 10 mm in diameter. Species-area curves were generated by plotting species number as a function of quadrat size; species-individual curves were generated from the same data, but using stem number as the independent variable rather than area. 2 Species-area curves had different forms for stems of different diameters, but species-individual curves were nearly independent of diameter class. With < 10(4) stems, species-individual curves were concave downward on log-log plots, with curves from different forests diverging, but beyond about 104 stems, the log-log curves became nearly linear, with all three sites having a similar slope. This indicates an asymptotic difference in richness between forests: the Malaysian site had 2.7 times as many species as Panama, which in turn was 3.3 times as rich as India. 3 Other details of the species-accumulation relationship were remarkably similar between the three sites. Rectangular quadrats had 5-27% more species than square quadrats of the same area, with longer and narrower quadrats increasingly diverse. Random samples of stems drawn from the entire 50 ha had 10-30% more species than square quadrats with the same number of stems. At both Pasoh and BCI, but not Mudumalai. species richness was slightly higher among intermediate-sized stems (50-100mm in diameter) than in either smaller or larger sizes, These patterns reflect aggregated distributions of individual species, plus weak density-dependent forces that tend to smooth the species abundance distribution and 'loosen' aggregations as stems grow. 4 The results provide support for the view that within each tree community, many species have their abundance and distribution guided more by random drift than deterministic interactions. The drift model predicts that the species-accumulation curve will have a declining slope on a log-log plot, reaching a slope of O.1 in about 50 ha. No other model of community structure can make such a precise prediction. 5 The results demonstrate that diversity studies based on different stem diameters can be compared by sampling identical numbers of stems. Moreover, they indicate that stem counts < 1000 in tropical forests will underestimate the percentage difference in species richness between two diverse sites. Fortunately, standard diversity indices (Fisher's sc, Shannon-Wiener) captured diversity differences in small stem samples more effectively than raw species richness, but both were sample size dependent. Two nonparametric richness estimators (Chao. jackknife) performed poorly, greatly underestimating true species richness.

Turbulent mixed convection in a shallow enclosure with a series of heat generating components

Turbulent mixed convection flow and heat transfer in a shallow enclosure with and without partitions and with a series of block-like heat generating components is studied numerically for a range of Reynolds and Grashof numbers with a time-dependent formulation. The flow and temperature distributions are taken to be two-dimensional. Regions with the same velocity and temperature distributions can be identified assuming repeated placement of the blocks and fluid entry and exit openings at regular distances, neglecting the end wall effects. One half of such module is chosen as the computational domain taking into account the symmetry about the vertical centreline. The mixed convection inlet velocity is treated as the sum of forced and natural convection components, with the individual components delineated based on pressure drop across the enclosure. The Reynolds number is based on forced convection velocity. Turbulence computations are performed using the standard k– model and the Launder–Sharma low-Reynolds number k– model. The results show that higher Reynolds numbers tend to create a recirculation region of increasing strength in the core region and that the effect of buoyancy becomes insignificant beyond a Reynolds number of typically 5×105. The Euler number in turbulent flows is higher by about 30 per cent than that in the laminar regime. The dimensionless inlet velocity in pure natural convection varies as Gr1/3. Results are also presented for a number of quantities of interest such as the flow and temperature distributions, Nusselt number, pressure drop and the maximum dimensionless temperature in the block, along with correlations.

Interrogating an insect society

Insect societies such as those of ants, bees, and wasps consist of 1 or a small number of fertile queens and a large number of sterile or nearly sterile workers. While the queens engage in laying eggs, workers perform all other tasks such as nest building, acquisition and processing of food, and brood care. How do such societies function in a coordinated and efficient manner? What are the rules that individuals follow? How are these rules made and enforced? These questions are of obvious interest to us as fellow social animals but how do we interrogate an insect society and seek answers to these questions? In this article I will describe my research that was designed to see answers from an insect society to a series of questions of obvious interest to us. I have chosen the Indian paper wasp Ropalidia marginata for this purpose, a species that is abundantly distributed in peninsular India and serves as an excellent model system. An important feature of this species is that queens and workers are morphologically identical and physiologically nearly so. How then does an individual become a queen? How does the queen suppress worker reproduction? How does the queen regulate the nonreproductive activities of the workers? What is the function of aggression shown by different individuals? How and when is the queen's heir decided? I will show how such questions can indeed be investigated and will emphasize the need for a whole range of different techniques of observation and experimentation.

A rapid and sensitive method for the estimation of individual tRNA pools

A rapid and sensitive method is described to quantitatively compare tRNA pools for individual aminoacids in a single experiment. The procedure comprises of: (i) charging of total tRNA with a mixture of radiolabeled aminoacids, (ii) deacylation of the esterified tRNA with a volatile base and the recovery of the labeled aminoacid, (iii) derivatisation of the aminoacid with phenylisothiocyanate after mixing with excess of nonradioactive aminoacids, (iv) baseline separation of the phenylthiocarbamyl aminoacids by reverse phase high performance liquid chromatography monitored by A254nm and (v) quantitation of the radioactivity in individual aminoacid peaks. The radioactivity in the aminoacid peak corresponds to the quantity of the aminoacylated tRNA. The method has been successfully applied to quantitate the individual tRNA pools in the developing silk glands of Bombyx mori, a functionally adapted tissue which undergoes considerable variations in tRNA content. PSG, posterior silk gland; PITC, phenylisothiocyanate; DMAA, N,N-dimethyl-N-allylamine; APH, algal protein hydrolysate; ptc-, phenylthiocarbamyl; HPLC, high performance liquid chromatography.

Resolution of racemic gossypol and interaction of individual enantiomers with serum albumins and model peptides

Racemic gossypol has been resolved by HPLC separation of diastereomeric (−) norepinephrine adducts on a reverse-phase column. The binding constants for the interaction of the three gossypol forms (+, − and −) with human and bovine serum albumins have been determined by fluoresence quenching studies. The KD values demonstrate that all three forms bind equally effectively to the two proteins, suggesting an absence of chiral discrimination in albumin-gossypol interactions. Circular dichroism studies of (+)-gossypol binding to the model dibasic peptides, Boc-Lys-Pro-Aib-Lys-NHMe and gramicidin S, suggesting that distortions of binaphthyl geometry may occur only for specific orientations of interacting residues at the receptor site.

Recognition And Top-Down Generation Of Beta-Acyclic Database Schemes

Database schemes can be viewed as hypergraphs with individual relation schemes corresponding to the edges of a hypergraph. Under this setting, a new class of "acyclic" database schemes was recently introduced and was shown to have a claim to a number of desirable properties. However, unlike the case of ordinary undirected graphs, there are several unequivalent notions of acyclicity of hypergraphs. Of special interest among these are agr-, beta-, and gamma-, degrees of acyclicity, each characterizing an equivalence class of desirable properties for database schemes, represented as hypergraphs. In this paper, two complementary approaches to designing beta-acyclic database schemes have been presented. For the first part, a new notion called "independent cycle" is introduced. Based on this, a criterion for beta-acyclicity is developed and is shown equivalent to the existing definitions of beta-acyclicity. From this and the concept of the dual of a hypergraph, an efficient algorithm for testing beta-acyclicity is developed. As for the second part, a procedure is evolved for top-down generation of beta-acyclic schemes and its correctness is established. Finally, extensions and applications of ideas are described.

Queuing Models for Estimating Aircraft Fleet Availability

The availability of a small fleet of aircraft in a flying-base, repair-depot combination is modeled and studied. First, a deterministic flow model relates parameters of interest and represents the state-of-the art in the planning of such systems. Second, a cyclic queue model shows the effect of the principal uncertainties in operation and repair and shows the consequent decrease in the availability of aircraft at the flying-base. Several options such as increasing fleet size, investments in additional repair facilities, or building reliability and maintainability into the individual aircraft during its life-cycle are open for increasing the availability. A life-cycle cost criterion brings out some of these features. Numerical results confirm Rose's prediction that there exists a minimal cost combination of end products and repair-depot capability to achieve a prescribed operational availability.

Increased Efficacies of an Individual Catalytic Site in Clustered Multivalent Dendritic Catalysts

In the studies reported so far on dendrimer-mediated catalysis, the efficacies of the catalytic units were studied and compared primarily across the generations. In order to identify the efficacy of an individual catalytic unit with respect to the number of such units present within a given generation, a series of catalysts were prepared within a generation. Dendrimers incorporated with phosphinemetal complexes were chosen for the study and as many as 11 catalysts within three generations were synthesized. The C-C bond-forming reactions, namely, the Heck and the Suzuki coupling reactions, were then selected to study the catalytic efficiencies of the series of partially and fully phosphine-metal complex functionalized dendrimers. The efficacies of the formation of cinnamate and biphenyl. catalyzed by the dendritic catalysts, were compared. The comparative analyses show that an individual catalytic site is far more effective in its catalytic activity when presented in multiple numbers, i.e., in a multivalent dendritic system, than as a single unit within the same generation, i.e., in a monovalent dendritic system. The study identifies the beneficial effects of the multivalent presentation of the catalytic moieties, both within and across the dendrimer generations.

Scouts, Promoters, and Connectors: The Roles of Ratings in Nearest-Neighbor Collaborative Filtering

Recommender systems aggregate individual user ratings into predictions of products or services that might interest visitors. The quality of this aggregation process crucially affects the user experience and hence the effectiveness of recommenders in e-commerce. We present a characterization of nearest-neighbor collaborative filtering that allows us to disaggregate global recommender performance measures into contributions made by each individual rating. In particular, we formulate three roles-scouts, promoters, and connectors-that capture how users receive recommendations, how items get recommended, and how ratings of these two types are themselves connected, respectively. These roles find direct uses in improving recommendations for users, in better targeting of items and, most importantly, in helping monitor the health of the system as a whole. For instance, they can be used to track the evolution of neighborhoods, to identify rating subspaces that do not contribute ( or contribute negatively) to system performance, to enumerate users who are in danger of leaving, and to assess the susceptibility of the system to attacks such as shilling. We argue that the three rating roles presented here provide broad primitives to manage a recommender system and its community.

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

The stochasticity of domain-wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time dependence of noise reveals a diffusive random walk of the DWs with a universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.

Regenerating Codes for Distributed Storage Networks

In a storage system where individual storage nodes are prone to failure, the redundant storage of data in a distributed manner across multiple nodes is a must to ensure reliability. Reed-Solomon codes possess the reconstruction property under which the stored data can be recovered by connecting to any k of the n nodes in the network across which data is dispersed. This property can be shown to lead to vastly improved network reliability over simple replication schemes. Also of interest in such storage systems is the minimization of the repair bandwidth, i.e., the amount of data needed to be downloaded from the network in order to repair a single failed node. Reed-Solomon codes perform poorly here as they require the entire data to be downloaded. Regenerating codes are a new class of codes which minimize the repair bandwidth while retaining the reconstruction property. This paper provides an overview of regenerating codes including a discussion on the explicit construction of optimum codes.

Loud calls of male Nilgiri langurs (Presbytis johnii): Age-, individual-, and population-specific differences

Adult male Nilgiri langurs (Presbytis johnii) utter loud call bouts consisting of one or more phrases. Phrases are made up of several units showing similar or different structural features. The units involved differ with respect to not only their physical structure but also their overall utilization: three vocal patterns are uttered exclusively by mature males living in bisexual groups or all-male bands and, in addition to being part of loud call bouts, are given during encounters with terrestrial predators; two vocal patterns are uttered by males and females, again not just as constituents of loud calls; and one vocal pattern is given exclusively by mature males living in bisexual groups. Within a given bout, phrases differ not only with respect to their composition but also in their temporal organization. In addition to the acoustic components, loud calls are regularly accompanied by stereotyped motoric displays. The motoric and acoustic components of loud call displays appear independently of each other and at different times during ontogeny. The development of the display is characterized by combination of units with different structural features and synchronization of vocal and motoric components. Although more evidence is needed, our observations suggest that the development of loud call displays coincides with the aquisitation of social maturation and competence and requires not only social experience but also a certain amount of motoric training. In spite of the high degree of ritualization, loud call displays are not completely fixed in form, but instead are open to individual- and population-specific variation.

Analysis of side-chain conformation in proteins

The crystal structures of a number of globular proteins are currently available. An analysis of the distribution of side-chains among different allowed conformations in these proteins has been carried out. The observed conformations of individual residues are discussed on the basis of well-known stereochemical criteria. The population distribution of side-chains in different allowed regions in conformational space can be explained largely on the basis of simple steric considerations. In addition to examining the conformational behaviour of individual residues, some population distributions of conformational angles of general interest involving groups of residues have also been analyzed.