Tracking by Animation: Unsupervised Learning of Multi-Object Attentive Trackers

Online Multi-Object Tracking (MOT) from videos is a challenging computer vision task which has been extensively studied for decades. Most of the existing MOT algorithms are based on the Tracking-by-Detection (TBD) paradigm combined with popular machine learning approaches which largely reduce the human effort to tune algorithm parameters. However, the commonly used supervised learning approaches require the labeled data (e.g., bounding boxes), which is expensive for videos. Also, the TBD framework is usually suboptimal since it is not end-to-end, i.e., it considers the task as detection and tracking, but not jointly. To achieve both label-free and end-to-end learning of MOT, we propose a Tracking-by-Animation framework, where a differentiable neural model first tracks objects from input frames and then animates these objects into reconstructed frames. Learning is then driven by the reconstruction error through backpropagation. We further propose a Reprioritized Attentive Tracking to improve the robustness of data association. Experiments conducted on both synthetic and real video datasets show the potential of the proposed model. Our project page is publicly available at: https://github.com/zhen-he/tracking-by-animationComment: CVPR 201

An attractor for the dynamical state of the intracluster medium

Galaxy clusters provide us with important information about the cosmology of our universe. Observations of the X-ray radiation or of the SZ effect allow us to measure the density and temperature of the hot intergalactic medium between the galaxies in a cluster, which then allow us to calculate the total mass of the galaxy cluster. However, no simple connection between the density and the temperature profiles has been identified. Here we use controlled high-resolution numerical simulations to identify a relation between the density and temperature of the gas in equilibrated galaxy clusters. We demonstrate that the temperature-density relation is a real attractor, by showing that a wide range of equilibrated structures all move towards the attractor when perturbed and subsequently allowed to relax. For structures which have undergone sufficient perturbations for this connection to hold, one can therefore extract the mass profile directly from the X-ray intensity profile.Comment: 7 pages, 3 figures, accepted by apj

PHYSIOCHEMICAL, PROXIMATE, AND SENSORY PROPERTIES OF UNFERMENTED AND FERMENTED SOY-CARROT BEVERAGES SWEETENED WITH SUGAR, DATE, AND HONEY

Objective: Physiochemical, proximate, and sensory properties of unfermented and fermented soy-carrot beverage sweetened with sugar, date, and honey were evaluated. Phytochemical content of soymilk, carrot juice, and their blend was also analyzed. Methods: Three sets of soy-carrot beverages were produced by homogenizing soy milk and carrot juice in a ratio of 2:1 and sweetened to 12% Brix. Each set was sweetened with sugar, date, and honey, respectively. A fourth set was unsweetened and served as control. After pasteurization, one part was fermented with pure culture of Lactobacillus acidophilus at 42°C for 24 h. Results: Fermentation significantly (p≤0.05) decreased pH (≥5.40–≤3.90), increased titratable acidity (≤0.55–≥0.90% lactic acid), and viscosity (≤0.65–≥0.87 Pa.S) of the soy-carrot beverages. Moisture, protein, fat, ash, carbohydrate, and energy content of unfermented beverages were 82.95– 93.95%, 2.15–2.87%, 0.42–1.21%, 0.10–0.20%, 3.21–12.55%, and 25.46–73.53 Kcal/g, respectively, while fermented beverages had 90.00–93.00%, 2.06–2.20%, 0.88–1.08%, 0.11–10.20%, 4.85–8.75%, and 36.76–52.20 Kcal/g, respectively. Total carotenoid, phenol, and DPPH radical scavenging activity varied, respectively, from 2.40–7.90, 14.81–26.59 mg tannic acid/ml, and 4.02–27.83% and were significantly (p≤0.05) highest in soy-carrot blend with carrot as major contributor. Degree of likeness of the sensory attributes for the sweetened and unfermented beverages was significantly (p≤0.05) higher than the fermented. Conclusion: Date and honey (12% Brix) can be used as sucrose alternatives in producing acceptable nutritious beverage from soymilk and carrot juice

PHYSICO-CHEMICAL, PROXIMATE COMPOSITION, ASCORBIC ACID, SENSORY, AND MICROBIOLOGICAL QUALITY OF MINIMALLY PROCESSED CARICA PAPAYA CONSUMED IN RIVERS STATE, NIGERIA

Objective: This study evaluated the physico-chemical, proximate, ascorbic acid, sensory, and microbiological properties of minimally processed Carica papaya consumed in Rivers State Nigeria. Methods: Minimally processed papaya in transparent polyethylene bags were purchased from four different locations: Nwinpi, Mile III, Rumuokuta, and Rumuokoro Junctions in Port Harcourt, Rivers State, Nigeria. Control sample was prepared in the laboratory. Standard analytical methods were used for analysis. Results: pH and titratable acidity ranged from 4.90–5.20 to 1.00–1.04% citric acid, respectively. Moisture, fat, ash, crude fiber, and carbohydrate ranged, respectively, from 85.80–89.60, 0.64–0.69, 0.55–0.96, 1.71–1.93, and 7.20–10.97%. Energy value was 35.31–50.07 kcal/g while protein was 0.09% for all samples. Ascorbic acid varied significantly (p<0.05) from 17.81 to 44.91 mg/100 g. Sensory results showed that 75% of the assessors’ degree of likeness for aroma, appearance/color, texture (smoothness), sweetness, and overall acceptability was that of moderate to extreme likeness. Total aerobic, coliform, Escherichia coli, Salmonella, and Staphylococcus aureus counts varied from 3.85–5.76, 3.74–5.68, 3.95–5.57, 3.82–5.58, and 3.30–5.45 Log10CFU/g, respectively. The control had significantly (p<0.05) the least bacterial count. Fungi count varied from 3.65 to 4.62 Log10CFU/g. Conclusion: The minimally processed papaya was low in acidity, rich in ascorbic acid and a good source of the nutrient. Sensory attributes of the products were acceptable to the assessors. Microbial counts were unsatisfactory and can pose a risk factor to public health

Market impact under a new regulatory regime: Credit rating agencies in Europe

We investigate whether there are any identifiable differences in market perceptions of rating news released by Moody’s, S&P and Fitch following the establishment of a new regulatory regime in July 2011, when the European Securities and Markets Authority assumed responsibility for rating agencies’ regulation in Europe. We focus the analysis on the impact of bank rating actions on stock returns and volatility during 2008-2013. Among the intended effects of the new regulatory regime are reduced market impact of rating actions and enhanced market stability, yet we find very mixed evidence. Differentials in market responses across CRAs are identified

Potts and percolation models on bowtie lattices

We give the exact critical frontier of the Potts model on bowtie lattices. For the case of $q=1$, the critical frontier yields the thresholds of bond percolation on these lattices, which are exactly consistent with the results given by Ziff et al [J. Phys. A 39, 15083 (2006)]. For the $q=2$ Potts model on the bowtie-A lattice, the critical point is in agreement with that of the Ising model on this lattice, which has been exactly solved. Furthermore, we do extensive Monte Carlo simulations of Potts model on the bowtie-A lattice with noninteger $q$. Our numerical results, which are accurate up to 7 significant digits, are consistent with the theoretical predictions. We also simulate the site percolation on the bowtie-A lattice, and the threshold is $s_c=0.5479148(7)$. In the simulations of bond percolation and site percolation, we find that the shape-dependent properties of the percolation model on the bowtie-A lattice are somewhat different from those of an isotropic lattice, which may be caused by the anisotropy of the lattice.Comment: 18 pages, 9 figures and 3 table

The clustering coefficient and community structure of bipartite networks

Many real-world networks display a natural bipartite structure. It is necessary and important to study the bipartite networks by using the bipartite structure of the data. Here we propose a modification of the clustering coefficient given by the fraction of cycles with size four in bipartite networks. Then we compare the two definitions in a special graph, and the results show that the modification one is better to character the network. Next we define a edge-clustering coefficient of bipartite networks to detect the community structure in original bipartite networks.Comment: 9 pages, 4 figure

Ranking the Risks from Multiple Hazards in a Small Community

Natural hazards, human-induced accidents, and malicious acts have caused great losses and disruptions to society. After September 11, 2001, critical infrastructure protection has become a national focus in the United States and is likely to remain one for the foreseeable future. Damage to our infrastructures and assets could be mitigated through pre-disaster planning and actions. We have developed a systematic methodology to assess and rank the risks from these multiple hazards in a community of 20,000 people. It is an interdisciplinary study that includes probabilistic risk assessment, decision analysis, and expert judgment. Scenarios are constructed to show how the initiating events evolve into undesirable consequences. A value tree, based on multi-attribute utility theory, is used to capture the decision maker’s preferences about the impacts on the infrastructures and other assets. The risks from random failures are ranked according to their Expected Performance Index, which is the product of frequency, probability, and consequence of a scenario. Risks from malicious acts are ranked according to their Performance Index as the frequency of attack is not available. A deliberative process is used to capture the factors that could not be addressed in the analysis and to scrutinize the results. This methodology provides a framework for the development of a risk-informed decision strategy. Although this study uses the Massachusetts Institute of Technology campus as a test-bed, it is a general methodology that could be used by other similar communities and municipalities