533 research outputs found
Constrained LQR Using Online Decomposition Techniques
This paper presents an algorithm to solve the infinite horizon constrained
linear quadratic regulator (CLQR) problem using operator splitting methods.
First, the CLQR problem is reformulated as a (finite-time) model predictive
control (MPC) problem without terminal constraints. Second, the MPC problem is
decomposed into smaller subproblems of fixed dimension independent of the
horizon length. Third, using the fast alternating minimization algorithm to
solve the subproblems, the horizon length is estimated online, by adding or
removing subproblems based on a periodic check on the state of the last
subproblem to determine whether it belongs to a given control invariant set. We
show that the estimated horizon length is bounded and that the control sequence
computed using the proposed algorithm is an optimal solution of the CLQR
problem. Compared to state-of-the-art algorithms proposed to solve the CLQR
problem, our design solves at each iteration only unconstrained least-squares
problems and simple gradient calculations. Furthermore, our technique allows
the horizon length to decrease online (a useful feature if the initial guess on
the horizon is too conservative). Numerical results on a planar system show the
potential of our algorithm.Comment: This technical report is an extended version of the paper titled
"Constrained LQR Using Online Decomposition Techniques" submitted to the 2016
Conference on Decision and Contro
Lipoplatin Formulation Review Article
Patented platform technologies have been used for the liposomal encapsulation of cisplatin (Lipoplatin) into tumor-targeted 110 nm (in diameter) nanoparticles. The molecular mechanisms, preclinical and clinical data concerning lipoplatin, are reviewed here. Lipoplatin has been successfully administered in three randomized Phase II and III clinical trials. The clinical data mainly include non-small-cell lung cancer but also pancreatic, breast, and head and neck cancers. It is anticipated that lipoplatin will replace cisplatin as well as increase its potential applications. For the first time, a platinum drug has shown superiority to cisplatin, at least in non-squamous non-small-cell lung cancer as reported in a Phase III study which documented a simultaneous lowering of all of the side effects of cisplatin
Cladding Pressures and Primary Structural System Forces of a Wood Building Exposed to Strong Winds.
Several studies have been carried out on the evaluation of wind-induced pressures on building envelopes. However, there is very limited research on wind-induced forces on the main structural elements of a building including its foundation. Thus, a full-scale monitoring research project was initiated to examine the wind-induced structural forces for a low-rise wood building. The field facilities include two weather stations and a test house equipped with load and pressure sensors. The house is resting on top of twenty-seven 3-axis load cells and is structurally isolated, i.e., the only points of contact between the foundation wall and the superstructure are the load cells. Simultaneously to the load monitoring, 40 pressure taps are recording the envelope pressures both on the roof and the wall surfaces. In addition to the field monitoring, a scaled model of the house was tested in a boundary layer wind tunnel using three different upstream terrain configurations that provided varying levels of turbulence characteristics suitable for comparisons with full-scale values. The analysis of the wind speed and direction field data confirmed the non-uniform variation of the basic terrain properties over the wind direction and this was also verified in the comparison of the field with the wind tunnel results. These comparisons were made in the form of both envelope pressures and total uplift forces at the foundation level and provided useful insight regarding the wind load path inside the structural elements of the building. Experimental findings were also compared to the Canadian Code and American Standard wind provisions and indicated an underestimation of the total uplift force when using the code and standard provisions in some cases
Algebraic-matrix calculation of vibrational levels of triatomic molecules
We introduce an accurate and efficient algebraic technique for the
computation of the vibrational spectra of triatomic molecules, of both linear
and bent equilibrium geometry. The full three-dimensional potential energy
surface (PES), which can be based on entirely {\it ab initio} data, is
parameterized as a product Morse-cosine expansion, expressed in bond-angle
internal coordinates, and includes explicit interactions among the local modes.
We describe the stretching degrees of freedom in the framework of a Morse-type
expansion on a suitable algebraic basis, which provides exact analytical
expressions for the elements of a sparse Hamiltonian matrix. Likewise, we use a
cosine power expansion on a spherical harmonics basis for the bending degree of
freedom. The resulting matrix representation in the product space is very
sparse and vibrational levels and eigenfunctions can be obtained by efficient
diagonalization techniques. We apply this method to carbonyl sulfide OCS,
hydrogen cyanide HCN, water HO, and nitrogen dioxide NO. When we base
our calculations on high-quality PESs tuned to the experimental data, the
computed spectra are in very good agreement with the observed band origins.Comment: 11 pages, 2 figures, containg additional supporting information in
epaps.ps (results in tables, which are useful but not too important for the
paper
O-band QKD link over a multiple ONT loaded carrier-grade GPON for FTTH applications
We have successfully integrated an O-band commercial Quantum-Key-Distribution
(QKD) system over a lit GPON testbed that replicates a carrier-grade
Fiber-to-the-Home (FTTH) optical access network with multiple ONTs to emulate
real-life FTTH operational deployments.Comment: 3 page
Assessment of proliferating cell nuclear antigen and its relationship with proinflammatory cytokines and parameters of disease activity in multiple myeloma patients
Multiple myeloma (MM) is a malignant plasma cell disease. Several proinflammatory cytokines produced by malignant plasma cells and bone marrow (BM) stromal cells are involved in the pathogenesis of the disease. We evaluated serum levels of the proinflammatory cytokines Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-8 (IL-8), macrophage inflammatory protein-1α (MIP-1α), in MM patients before treatment, and determined its significance in tumor progression. We also analyzed the correlation between measured parameters with proliferating cell nuclear antigen (PCNA). Forty-four MM patients and 20 healthy controls were studied. Serum levels of the proinflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA), whereas PCNA value in the BM was determined by immunohistochemistry staining. The mean concentrations of the measured cytokines were significantly different among the three stages of disease, with higher values in advanced disease stage. Furthermore, patients with MM had significantly higher serum levels of the measured cytokines than in controls. A positive correlation was found between IL-6 with IL-1β, IL-8 and MIP-1α. Similarly, IL-8 and MIP-1α were positively correlated with markers of disease activity such as β2 microglobulin and LDH. The proliferation index, determined by PCNA immunostaining, was higher in advanced disease stage. Furthermore PCNA value correlated significantly with β2 microglobulin, LDH and the levels of the measured cytokines. Our results showed that the proliferative activity, as measured with PCNA, increases in parallel with disease stage. The positive correlation between PCNA and other measured mediators supports the involvement of these factors in the biology of myeloma cell growth and can be used as markers of disease activity and as possible therapeutic targets
CFD Simulation of Near-Field Pollutant Dispersion on a High-Resolution Grid: A Case Study by LES and RANS for a Building Group in Downtown Montreal
Turbulence modeling and validation by experiments are key issues in the simulation of micro-scale atmospheric dispersion. This study evaluates the performance of two different modeling approaches (RANS standard k-ε and LES) applied to pollutant dispersion in an actual urban environment: downtown Montreal. The focus of the study is on near-field dispersion, i.e. both on the prediction of pollutant concentrations in the surrounding streets (for pedestrian outdoor air quality) and on building surfaces (for ventilation system inlets and indoor air quality). The high-resolution CFD simulations are performed for neutral atmospheric conditions and are validated by detailed wind-tunnel experiments. A suitable resolution of the computational grid is determined by grid-sensitivity analysis. It is shown that the performance of the standard k-ε model strongly depends on the turbulent Schmidt number, whose optimum value is case-dependent and a priori unknown. In contrast, LES with the dynamic subgrid-scale model shows a better performance without requiring any parameter input to solve the dispersion equation
Near-field Pollutant Dispersion in an Actual Urban Area: Analysis of the Mass Transport Mechanism by High-Resolution Large Eddy Simulation
Large-Eddy Simulation of near-field pollutant dispersion from stacks on the roof of a low-rise building in downtown Montreal is performed. Two wind directions are considered, with different wind-flow patterns and plume behavior. The computed mean concentration field is analyzed by means of the convective and turbulent (including subgrid-scale) mass fluxes. This decomposition provides insight into the dispersion process and allows an evaluation of common turbulent transport models used with the Reynolds-Averaged Navier–Stokes approach, such as the standard gradient-diffusion hypothesis. Despite the specific character of the flow and dispersion patterns due to the complex geometry of the urban area under study, some similarities are found with the generic case of dispersion around an isolated simple building. Moreover, the analysis of dispersion in downtown Montreal is facilitated by the physical insight gained by the study of the generic case. In this sense, the present study supports the use of generic, simplified cases to investigate and understand environmental processes as they occur in real and more complex situations. Reciprocally, the results of this applied study show the influence on the dispersion process of the rooftop structures and of the orientation of the emitting building with respect to the incoming wind flow, providing directions for further research on generic cases
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