6,692 research outputs found
Simulation framework of port operation and recovery planning
This study proposes a framework of simulation tool suites for ports to evaluate their response to disaster crisis and port security policies. The focus is containerized cargos that are imported through ports in the U.S. with final destinations also in the U.S. A crisis, such as a man-made or natural disaster, may cause a delay at the seaport. The down time of ports may result in severe economic losses. Thus, when a seaport cannot normally operate, it is important to minimize the impact caused by the disrupted freight flow. Port security policies also have a significant impact on the port operation efficiency. This model developed in this study evaluates the performance of re-routing strategies under different crisis scenarios and can help the user to find an effective re-routing decision and analyze security policies of a port. This model also analyzes security policies of the simulation port
Graphics processing unit accelerating compressed sensing photoacoustic computed tomography with total variation
Photoacoustic computed tomography with compressed sensing (CS-PACT) is a commonly used imaging strategy for sparse-sampling PACT. However, it is very time-consuming because of the iterative process involved in the image reconstruction. In this paper, we present a graphics processing unit (GPU)-based parallel computation framework for total-variation-based CS-PACT and adapted into a custom-made PACT system. Specifically, five compute-intensive operators are extracted from the iteration algorithm and are redesigned for parallel performance on a GPU. We achieved an image reconstruction speed 24–31 times faster than the CPU performance. We performed in vivo experiments on human hands to verify the feasibility of our developed method
Controllability of multi-agent systems with input and communication delays
Distributed cooperative control of multi-agent systems is broadly applied in artificial intelligence in which time delay is of great concern because of its ubiquitous. This paper considers the controllability of leader-follower multi-agent systems with input and communication delays. For the first-order systems with input delay, neighbor-based protocol is adopted to realize the interactions among agents, yielding a system with delay existed in state and control input. New notions of interval controllability and interval structural controllability for the system are defined. Algebraic criterion is established for interval controllability, and graph-theoretic interpretation is put forward for the interval structural controllability. Results imply that input delay of the multi-agent systems has significant influence on the interval controllability and interval structural controllability. Corresponding conclusions are generalized to the first-order systems and the high-order ones with communication delays, respectively. Example is attached to illustrate the work
A Model-Based Method for Minimizing CVaR and Beyond
We develop a variant of the stochastic prox-linear method for minimizing the
Conditional Value-at-Risk (CVaR) objective. CVaR is a risk measure focused on
minimizing worst-case performance, defined as the average of the top quantile
of the losses. In machine learning, such a risk measure is useful to train more
robust models. Although the stochastic subgradient method (SGM) is a natural
choice for minimizing the CVaR objective, we show that our stochastic
prox-linear (SPL+) algorithm can better exploit the structure of the objective,
while still providing a convenient closed form update. Our SPL+ method also
adapts to the scaling of the loss function, which allows for easier tuning. We
then specialize a general convergence theorem for SPL+ to our setting, and show
that it allows for a wider selection of step sizes compared to SGM. We support
this theoretical finding experimentally
Study the Heavy Molecular States in Quark Model with Meson Exchange Interaction
Some charmonium-like resonances such as X(3872) can be interpreted as
possible molecular states. Within the quark model, we study
the structure of such molecular states and the similar
molecular states by taking into account of the light meson exchange (,
, , and ) between two light quarks from different
mesons
[(3aS,5aR,8aR,8bS)-2,2,7,7-Tetramethyltetrahydro-3aH-bis[1,3]dioxolo[4,5-b:4′,5′-d]pyran-3a-yl]methyl (R)-N-(1-phenylethyl)sulfamate
In the title compound, C20H29NO8S, the two five-membered rings adopt envelope conformations (with an O atom at the flap in each case), while the six-membered pyran ring displays a twist-boat conformation. In the crystal, molecules are linked by N—H⋯O hydrogen bonds into a supramolecular chain running along the a axis
Hi, Magic Closet, Tell Me What to Wear!
In this demo, we present a practical system, magic closet, for automatic occasion-oriented clothing pairing. Given a user-input occasion, e.g., wedding or shopping, the magic closet intelligently and automatically pairs the user-specified reference clothing (upper body or lower body) with the most suitable one from online shops. Two key criteria are explicitly considered for the magic closet system. One criterion is to dress properly, e.g., compared to suit pants, it is more decent to wear a cocktail dress for a banquet occasion. The other criterion is to dress aesthetically, e.g., a red T-shirt matches better with white pants than with green pants.
To narrow the semantic gap between the low-level visual features and the high-level occasion categories, we propose to adopt middle-level clothing attributes (e.g., clothing category, color, pattern) as a bridge. More specifically, the clothing attributes are treated as latent variables in our proposed latent Support Vector Machine (SVM)-based recommendation model.
The properly criterion is described through a feature-occasion potential and an attribute-occasion potential, while the aesthetically criterion is expressed by an attribute-attribute potential
- …