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Fighting the jar of gherkinsHentschel, Christian 31 May 2012 (has links) (PDF)
Opening food packages without additional aids is a common problem, which especially affects elder people. A study carried out at the Professorship of Human Factors and Ergonomics shows results of opening successes at a variety of packages. Opening a jar of gherkins proved to be a challenging task for the majority of the test persons. Further examples of badly designed packages as well as good solutions are introduced.
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Ultra-thin Ceramic Films for Low-temperature Temperature Embedding of Decoupling Capacitors into Organic Printed Wiring BoardsBalaraman, Devarajan 27 October 2005 (has links)
As microprocessors move towards higher frequencies, lower operating voltages and higher power consumption, supplying noise-free power to the ICs becomes increasingly challenging. Decoupling capacitors with low inductance interconnections are critical to meet the power supply impedance targets. A variety of capacitors are used today to provide decoupling at different frequencies. Surface-mount multi-layer ceramic capacitors currently used at package level provide decoupling only till about 100 MHz because of the component and lead inductances. Embedding thin film capacitors into the package can expand the operating range of package level capacitors to low GHz frequencies. Thin films with capacitance of several microfarads and organic-compatible processes are required for embedding decoupling capacitors at package level.
The organic-compatible high-permittivity materials available today do not provide adequate capacitance for the application on hand. While ferroelectric thin films can provide the required capacitance, processing temperatures over 300o C are required to achieve crystalline films with high permittivity. Hence, there is a need to develop novel materials and processes to integrate decoupling capacitors into currently prevalent organic packages. To this end, hydrothermal synthesis and sol-gel synthesis of BaTiO3 films were explored in this study. BaTiO3 films were synthesized by low temperature hydrothermal conversion of metallic titanium. Hydrothermal process parameters such as bath molarity and temperature were optimized to obtain thin films with grain sizes close to 100 nm, at temperatures less than 100o C. Novel post-hydrothermal treatments were developed to improve the dielectric properties of the films. Sol-gel process requires sintering at >700o C to obtain crystalline BaTiO3 films. However, the films can be synthesized on free-standing copper foils and subsequently integrated into organic packages using lamination. Prevention of foil oxidation during sintering is critical. Nickel and titanium barriers explored in this study were ineffective due to instabilities at the interfaces. Hence, films were synthesized on bare copper foils by controlling the oxygen partial pressure during sintering. Using these techniques BaTiO3 thin films with capacitances of 400 1000 nF/cm2 and breakdown voltages of 6 15 V were demonstrated. The films synthesized via either techniques exhibited stable dielectric properties up to 8 GHz owing to fine grain sizes.
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A Recommendation System for Preconditioned Iterative SolversGeorge, Thomas 2009 December 1900 (has links)
Solving linear systems of equations is an integral part of most scientific simulations. In
recent years, there has been a considerable interest in large scale scientific simulation of
complex physical processes. Iterative solvers are usually preferred for solving linear systems
of such magnitude due to their lower computational requirements. Currently, computational
scientists have access to a multitude of iterative solver options available as "plug-and-
play" components in various problem solving environments. Choosing the right solver
configuration from the available choices is critical for ensuring convergence and achieving
good performance, especially for large complex matrices. However, identifying the
"best" preconditioned iterative solver and parameters is challenging even for an expert due
to issues such as the lack of a unified theoretical model, complexity of the solver configuration
space, and multiple selection criteria. Therefore, it is desirable to have principled
practitioner-centric strategies for identifying solver configuration(s) for solving large linear
systems.
The current dissertation presents a general practitioner-centric framework for (a) problem
independent retrospective analysis, and (b) problem-specific predictive modeling of
performance data. Our retrospective performance analysis methodology introduces new
metrics such as area under performance-profile curve and conditional variance-based finetuning
score that facilitate a robust comparative performance evaluation as well as parameter
sensitivity analysis. We present results using this analysis approach on a number of popular
preconditioned iterative solvers available in packages such as PETSc, Trilinos, Hypre, ILUPACK, and WSMP. The predictive modeling of performance data is an integral part
of our multi-stage approach for solver recommendation. The key novelty of our approach
lies in our modular learning based formulation that comprises of three sub problems: (a)
solvability modeling, (b) performance modeling, and (c) performance optimization, which
provides the flexibility to effectively target challenges such as software failure and multiobjective
optimization. Our choice of a "solver trial" instance space represented in terms
of the characteristics of the corresponding "linear system", "solver configuration" and their
interactions, leads to a scalable and elegant formulation. Empirical evaluation of our approach
on performance datasets associated with fairly large groups of solver configurations
demonstrates that one can obtain high quality recommendations that are close to the ideal
choices.
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An Additive Bivariate Hierarchical Model for Functional Data and Related ComputationsRedd, Andrew Middleton 2010 August 1900 (has links)
The work presented in this dissertation centers on the theme of regression and
computation methodology. Functional data is an important class of longitudinal
data, and principal component analysis is an important approach to regression with
this type of data. Here we present an additive hierarchical bivariate functional data
model employing principal components to identify random e ects. This additive
model extends the univariate functional principal component model. These models
are implemented in the pfda package for R. To t the curves from this class of models
orthogonalized spline basis are used to reduce the dimensionality of the t, but retain
exibility. Methods for handing spline basis functions in a purely analytical manner,
including the orthogonalizing process and computing of penalty matrices used to t
the principal component models are presented. The methods are implemented in the
R package orthogonalsplinebasis.
The projects discussed involve complicated coding for the implementations in R.
To facilitate this I created the NppToR utility to add R functionality to the popular
windows code editor Notepad . A brief overview of the use of the utility is also
included.
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Reliability Study of IC Packages with Hygrothermal EffectChen, Thai-ping 29 May 2007 (has links)
It is an important issue for manufacturing and operation to formulate reliability about the effects of the moisture absorption and IR reflow parameters on IC packages. Two problems, the warpage of the thin IC package, and characterizing the adhesion features of IC package¡¦s interface, are studied in this dissertation. In a thin IC package, the CTE and CHE mismatch between materials are primarily attributed to the warpage which occurs when the package is being mounted on a PCB. The existence of defects in the corresponding interfaces can gradually degrade the interfacial adhesion when IC package is exposed to the high temperature and humidity. In this dissertation, the stability equations for the warpage in a thin IC package without the solder balls being subjected to hygrothermal loading, by modeling it as an initially perfect/imperfect composite plate, is developed. The analytical closed-form solutions are found and used to compute not only the critical moisture content but also the warpage occurrence before the critical loads are reached. The hygrothermal buckling phenomenon is checked by shadow moiré whole-field maps with different moisture content. The results indirectly indicate that the thin PBGA package has little imperfection. For characterizing the adhesion features of IC package¡¦s interface, the fuzzy controller is used to stabilize multiple performance characteristics, i.e., the moisture weight gain and adhesion strength, for the button shear test specimen. Parameters design, although based on the Taguchi method, can optimize the performance characteristic through the setting of process parameters and can reduce the sensitivity of the system performance to sources of variation. The control rules of the fuzzy controller were formed using the author¡¦s experience and knowledge of IC packaging process. The control parameters to be tuned were the membership functions. Therefore, the controller¡¦s performance depended on the membership functions. The fuzzy controller combined Taguchi parameter design, which makes the control performance insensitive to the operating condition change and noise, was used to determine the membership functions.
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Thrust Vector Control By Secondary InjectionErdem, Erinc 01 September 2006 (has links) (PDF)
A parametric study on Secondary Injection Thrust Vector Control (SITVC) has been accomplished numerically with the help of a commercial Computational Fluid Dynamics (CFD) code called FLUENT® / . This study consists of two parts / the first part includes the simulation of three dimensional flowfield inside a test case nozzle for the selection of parameters associated with both computational grid and the CFD solver such as mesh size, turbulence model accompanied with two different wall treatment approaches, and solver type. This part revealed that simulation of internal flowfield by a segregated solver with Realizable k-& / #949 / (Rke) turbulence model accompanied by enhanced wall treatment approach is accurate enough to resolve this kind of complex three dimensional fluid flow problems. In the second part a typical rocket nozzle with conical diverging section is picked for the parametric study on injection mass flow rate, injection location and injection angle. A test matrix is constructed / several numerical simulations are run to yield the assessment of performance of SITVC system. The results stated that for a nozzle with a small divergence angle, downstream injections with distances of 2.5-3.5 throat diameters from the nozzle throat lead to higher efficiencies over a certain range of total pressure ratios, i.e., mass flow rate ratios, upstream injections should be aligned more to the nozzle axis, i.e., higher injection angles, to prevent reflection of shock waves from the opposite wall and thus low efficiencies. Injection locations that are too much downstream may result reversed flows on nozzle exit.
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Imf Stabilization Packages And Development: Argentina In The 1990Kencebay, Betul 01 December 2006 (has links) (PDF)
This thesis analyzes the IMF stabilization packages and how those packages may affect the development. In order to explain the applications of the Packages, Argentine case is discussed for the period of 1990&rsquo / s. By analyzing the theories behind the IMF Stabilization packages, it is aimed to explain the conditionalities, actions and results, as could be observed in Argentine case.
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The Resource Allocation Capabilities Of Commercial Project Management Software Packages For Resource Constrained Project Scheduling ProblemCekmece, Kerem 01 March 2009 (has links) (PDF)
Resource constrained project scheduling problem (RCPSP) has been subject of extensive
research in project management literature as RCPSP is one of the most challenging
problems in the project management and is of great practical importance. In
this thesis, resource allocation capabilities of Primavera Enterprise V.6.0-Project
Management (P6) and MS Project 2007 (MS) were evaluated for solving overallocated
problems in the RCPSP. Fourty-five resource overallocated instance projects
were selected from the PSPLIB to evaluate performance of P6 and MS Project
2007. Three resource allocation priority rules of P6 and two resource allocation
priority rules of MS were used for comparision. The best solutions of different priority
rules for P6 and MS were compared by using t-test. Results of the P6 and MS
were compared with the lower bounds and optimum solutions of the previous heuristic
methods. The comparisions indicate that both P6 and MS has limited capabilities
for solving overallocated problems in RCPSP. Especially for larger projects the
widely used project management software packages can not provide optimum or
near optimum solutions.
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Thermal and mechanical analysis of interconnect structures in 3D stacked packagesWakil, Jamil Abdul 07 January 2011 (has links)
Physical scaling limits of microelectronic devices and the need to improve electrical performance have driven significant research and development into 3D architecture. The development of die stacks in first level packaging is one of the more viable short-term options for improved performance. Placement of memory die above or below processors in a traditional flip chip C4 package with through-silicon vias (TSVs) has significant benefits in reducing data and power transmission paths. However, with the electrical performance benefits come great thermal and mechanical challenges. There are two key objectives for this work. The first is understanding of the die-die interface resistance, R[subscript dd], composed of the back end of line (BEOL) layers and micro-C4 interconnects. The interfacial resistance between BEOL material layers, the impact of TSVs and the impact of strain on R[subscript dd] are subtopics. The second key objective is the understanding of package thermal and mechanical behavior under operating conditions, such as local thermal disturbances. To date, these topics have not been adequately addressed in the literature. It is found that R[subscript dd] can be affected by TSVs, and that the interfacial contributions predicted by theoretical sub-continuum models can be significantly different than measurements. Using validated finite element models, the significance of the power distribution and R[subscript dd] on the temporal responses of 2D vs. 3D packages is highlighted. The results suggest local thermal hotspots can greatly exacerbate the thermal penalty due to the R[subscript dd] and that no peaks in stress arise in the transient period from power on to power off. / text
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Going With the Grain: Development, Knowledge Creation, and Database use at the International Maize and Wheat Improvement Center (CIMMYT)Burnett, Samuel Gray 01 August 2013 (has links)
Record keeping is not a static way to document history but rather a way for people in the present to engage with, and be affected by, the past. This is especially true in the case of online databases. Databases store information but their use also encourages the adoption of specific methodologies for apprehending reality because it is through those methodological agreements that the information in the database becomes relevant. In the summer of 2012 I spent four months observing and interviewing wheat researchers and database developers at a major agricultural research center in Mexico as part of my M.A. thesis project. This paper argues that people using the International Wheat Information System (IWIS) database at the International Maize and Wheat Improvement Center (CIMMYT) are involved in a process that documents wheat pedigree information while also enacting a reality based on assumptions about the value of certain types of human pedigree.
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