1,230 research outputs found
Prioritizing Content of Interest in Multimedia Data Compression
Image and video compression techniques make data transmission and storage in digital multimedia systems more efficient and feasible for the system's limited storage and bandwidth. Many generic image and video compression techniques such as JPEG and H.264/AVC have been standardized and are now widely adopted. Despite their great success, we observe that these standard compression techniques are not the best solution for data compression in special types of multimedia systems such as microscopy videos and low-power wireless broadcast systems. In these application-specific systems where the content of interest in the multimedia data is known and well-defined, we should re-think the design of a data compression pipeline. We hypothesize that by identifying and prioritizing multimedia data's content of interest, new compression methods can be invented that are far more effective than standard techniques. In this dissertation, a set of new data compression methods based on the idea of prioritizing the content of interest has been proposed for three different kinds of multimedia systems. I will show that the key to designing efficient compression techniques in these three cases is to prioritize the content of interest in the data. The definition of the content of interest of multimedia data depends on the application. First, I show that for microscopy videos, the content of interest is defined as the spatial regions in the video frame with pixels that don't only contain noise. Keeping data in those regions with high quality and throwing out other information yields to a novel microscopy video compression technique. Second, I show that for a Bluetooth low energy beacon based system, practical multimedia data storage and transmission is possible by prioritizing content of interest. I designed custom image compression techniques that preserve edges in a binary image, or foreground regions of a color image of indoor or outdoor objects. Last, I present a new indoor Bluetooth low energy beacon based augmented reality system that integrates a 3D moving object compression method that prioritizes the content of interest.Doctor of Philosoph
Manpower planning and cycle-time reduction of a labor-intensive assembly line
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 49).The demand for Gas Lift Mandrels(GLM) in the oil and gas industry is expected to increase over the next few years, requiring Schlumberger's GLM assembly line to increase their manufacturing capacity. Given the labor-intensive nature of Schlumberger's GLM assembly line, other than implementing kaizens and purchasing more equipment, it is important to also consider manpower issues. This research analyzes manpower management issues in the GLM assembly line to meet the projected increase in customer demand over the next three years. A detailed time study was conducted to understand and characterize all processes in the assembly line, before manpower plans were drawn up for each year till 2013. Several manpower scheduling concepts were incorporated in the manpower plan, such as Job Rotation and Workforce Flexibility to optimize the rate of utilization, human performance and well-being. By clustering processes together, the labor utilization rate can be increased to more than ninety percent. A new position of grinders has also been proposed to assist in various grinding operations, in order to reduce the cycle times of processes, to help workers gain better focus in their work and to reduce the cost of labor.by Shao Chong Oh.M.Eng
Resummation Prediction on Higgs and Vector Boson Associated Production with a Jet Veto at the LHC
We investigate the resummation effects for the SM Higgs and vector boson
associated production at the LHC with a jet veto in soft-collinear effective
theory using "collinear anomalous" formalism. We calculate the jet vetoed
invariant mass distribution and the cross section for this process at
Next-to-Next-to-Leading-Logarithmic level, which are matched to the QCD
Next-to-Leading Order results, and compare the differences of the resummation
effects with different jet veto and jet radius . Our
results show that both resummation enhancement effects and the scale
uncertainties decrease with the increasing of jet veto and
jet radius , respectively. When GeV and ,
the resummation effects reduce the scale uncertainties of the Next-to-Leading
Order jet vetoed cross sections to about , which lead to increased
confidence on the theoretical predictions. Besides, after including resummation
effects, the PDF uncertainties of jet vetoed cross section are about .Comment: 22 pages, 10 figures and 2 tables; final version in JHE
Modeling of Turbulent Sooting Flames
Modeling multiphase particles in turbulent fluid environment is a challenging task. To accurately describe the size distribution, a large number of scalars need to be transported at each time-step. Add to that the heat release and species mass fraction changes from nonlinear combustion chemistry reactions, and you have a tightly coupled set of equations that describe the (i) turbulence, (ii) chemistry, and (iii) soot particle interactions (physical agglomeration and surface chemistry reactions). Uncertainty in any one of these models will inadvertently introduce errors of up to a few orders of magnitude in predicted soot quantities. The objective of this thesis is to investigate the effect of turbulence and chemistry on soot evolution with respect to different soot aerosol models and to develop accurate models for simulating soot evolution in aircraft combustors. To investigate the effect of small scale turbulence time-scales on soot evolution, a partially-stirred reactor (PaSR) configuration is used and coupled with soot models from semi-empirical to detailed statistical models. Differences in soot property predictions including soot particle diameter and number density among the soot models are highlighted. The soot models will then be used to simulate the turbulent sooting flame in an aircraft swirl combustor to determine the large scale soot-turbulence-chemistry interactions. Highlights of this study include the differences in location of bulk soot mass production in the combustor using different soot models. A realistic aircraft combustor operating condition is simulated using a state-of-the-art minimally dissipative turbulent combustion solver and soot method of moments to investigate pressure scaling and soot evolution in different operating conditions. A separate hydrodynamic scaling is introduced to the pressure scaling, in addition to thermochemical scaling from previous studies. Finally, a Fourier analysis of soot evolution in the combustor will be discussed. A lower sooting frequency mode is found in the combustor, separate from the dominant fluid flow frequency mode that could affect statistical data collection for soot properties in turbulent sooting flame simulations.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147513/1/stchong_1.pd
Search for the signal of monotop production at the early LHC
We investigate the potential of the early LHC to discover the signal of
monotops, which can be decay products of some resonances in models such as
R-parity violating SUSY or SU(5), etc. We show how to constrain the parameter
space of the models by the present data of boson hadronic decay branching
ratio, mixing and dijet productions at the LHC. Then, we study
the various cuts imposed on the events, reconstructed from the hadronic final
states, to suppress backgrounds and increase the significance in detail. And we
find that in the hadronic mode the information from the missing transverse
energy and reconstructed resonance mass distributions can be used to specify
the masses of the resonance and the missing particle. Finally, we study the
sensitivities to the parameters at the LHC with =7 TeV and an
integrated luminosity of in detail. Our results show that the
early LHC may detect this signal at 5 level for some regions of the
parameter space allowed by the current data.Comment: 25 pages, 18 figures, 3 tables, version published in Phys.Rev.
Threshold Resummation for WZ and ZZ Pair Production at the LHC
We perform the threshold resummation for WZ and ZZ pair production at the
next-to-next-to-leading logarithmic accuracy in Soft-Collinear Effective Theory
at the LHC. Our results show that the resummation effects increase the total
cross sections by about 7% for ZZ production and 12% for WZ production
with$\sqrt{S}= 7,~8,~13 and 14 TeV, respectively, and the scale uncertainties
are significantly reduced. Besides, our numerical results are well consistent
with experimental data reported by the ATLAS and CMS collaborations.Comment: 14 pages, 8 figures, 2 tables, version published in Phys.Rev.
Soft gluon resummation in the signal-background interference process of
We present a precise theoretical prediction for the signal-background
interference process of , which is useful to constrain the
Higgs boson decay width and to measure Higgs couplings to the SM particles. The
approximate NNLO -factor is in the range of (),
depending on , at the 8 (13) TeV LHC. And the soft gluon resummation
can increase the approximate NNLO result by about at both the 8 TeV and
13 TeV LHC. The theoretical uncertainties including the scale, uncalculated
multi-loop amplitudes of the background and PDF are roughly
at . We also confirm that the approximate
-factors in the interference and the pure signal processes are the same.Comment: 18 pages, 9 figures; v2 published in JHE
Searching for the signal of dark matter and photon associated production at the LHC beyond leading order
We study the signal of dark matter and photon associated production induced
by the vector and axial-vector operators at the LHC, including the QCD
next-to-leading order (NLO) effects. We find that the QCD NLO corrections
reduce the dependence of the total cross sections on the factorization and
renormalization scales, and the factors increase with the increasing of the
dark matter mass, which can be as large as about 1.3 for both the vector and
axial-vector operators. Using our QCD NLO results, we improve the constraints
on the new physics scale from the results of the recent CMS experiment.
Moreover, we show the Monte Carlo simulation results for detecting the
\gamma+\Slash{E}_{T} signal at the QCD NLO level, and present the integrated
luminosity needed for a discovery at the 14 TeV LHC . If the signal
is not observed, the lower limit on the new physics scale can be set.Comment: 19 pages, 18 figures, 2 tables, version published in Phys.Rev.
Phenomenology of an Extended Higgs Portal Inflation Model after Planck 2013
We consider an extended inflation model in the frame of Higgs portal model,
assuming a nonminimal coupling of the scalar field to the gravity. Using the
new data from Planck and other relevant astrophysical data, we obtain
the relation between the nonminimal coupling and the self-coupling
needed to drive the inflation, and find that this inflationary model
is favored by the astrophysical data. Furthermore, we discuss the constraints
on the model parameters from the experiments of particle physics, especially
the recent Higgs data at the LHC.Comment: 21 pages, 8 figures; Version published in EPJ
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