Network Selection Optimization in a Secured Mobile IP Data Overlay System

The purpose of this thesis to so solve a limitation in the switchover mechanism of a Mobile IP (MIP) client device where it fails to change the active Mobile IP leg in a scenario where the current used path is just marginally good. The MIP client is a Cisco 819 router that provides internet connectivity to end users via an internal radio interface to a public Mobile Network Operator (MNO) and an external modem connected via an Ethernet port. When Mobile IP fails to properly select the active leg, the end user’s experience detriments and is unable to continue normal operation, this is why a mechanism is needed to probe the available networks and to select the best one for the end user. This work studies different vertical handover mechanisms that could be used in this type of environments where not only, not all the participants of the handover selection are radio interfaces; as in this case one interface is an external device, but also where most of the physical information of an interface is not available to use as part of a handover algorithm. This thesis proposes three different mechanisms to choose the best available network at any given time to complement the Mobile IP operation. The first mechanism is based on Round-Trip-Time (RTT), the next mechanism uses immediate throughput as the metric for the network selection and the final proposal is a muti-attribute algorithm where very poor networks will be filtered by their larger RTT values first and only then will the immediate available throughput will be measured. The results show that the three mechanisms provided a decrease in the downtime experienced by the end user where the RTT-based algorithm had the lowest increase in performance and the immediate-throughput-based proposal had the highest increase. The multi-attribute mechanism; while not top performing in terms of less downtime, significantly reduced the amount of time it took to select the new network and thus provides better end user experience

Examining assistance in a scenario-based test of L2 argumentative speaking ability: A learning-oriented approach for assessing complex competencies in language education.

The current study explored the assessment of English Language Learners’ argumentative speaking ability. Specifically, the study involved the development and administration of a scenario-based test that aimed to measure learners’ ability to display competency in L2 argumentative speaking ability by building an argument from factual evidence and presenting it to a simulated audience. In addition, the study aimed to examine whether embedding assistance in the test can help overcome gaps in background knowledge. Following a mixed-methods approach, results from the test administration were analyzed using robust statistical analyses (e.g., MG-Theory, Rasch Analysis, Multiple Regression) and qualitative analysis of the responses (e.g., rhetorical moves and theme-based analysis). A learning-oriented approach (Purpura & Turner, 2018) to assessment as a design and validation framework was used to interpret qualitative and quantitative evidence. It is hoped that this research project will shed light on the assessment of a foreign language within complex tasks and will help understand the affordances of implementing embedded assistance in language assessment

Forcespinning: A new method for the mass production of Sn/C composite nanofiber anodes for lithium ion batteries

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA h g− 1 at a current density of 100 mA g− 1 for over 50 cycles compared to most nanofiber electrodes prepared by electrospinning and centrifugal spinning. The FS method clearly produces Sn/C nanofiber composite electrodes that have a high specific capacity and excellent cyclic performance, owing to the unique structure and properties of the nanofibers. The FS technology is thus a viable method for the large scale production of nano/micro fibers for battery electrodes, separators, and other applications. To the best of our knowledge, this is the first time to report results on the use of Forcespinning technology to produce composite nanofiber anodes for lithium-ion batteries

On The Gould’s Formula for Stirling Numbers of The Second Kind

We present an alternative deduction of the Gould’s relation for Stirling numbers of the second kind. Our approach is based in the Nörlund polynomials and in the duality property between the Stirling numbers

Thermal Jeans fragmentation within 1000 AU in OMC-1S

We present subarcsecond 1.3 mm continuum ALMA observations towards the Orion Molecular Cloud 1 South (OMC-1S) region, down to a spatial resolution of 74 AU, which reveal a total of 31 continuum sources. We also present subarcsecond 7 mm continuum VLA observations of the same region, which allow to further study fragmentation down to a spatial resolution of 40 AU. By applying a Mean Surface Density of Companions method we find a characteristic spatial scale at ~560 AU, and we use this spatial scale to define the boundary of 19 `cores' in OMC-1S as groupings of millimeter sources. We find an additional characteristic spatial scale at ~2900 AU, which is the typical scale of the filaments in OMC-1S, suggesting a two-level fragmentation process. We measured the fragmentation level within each core and find a higher fragmentation towards the southern filament. In addition, the cores of the southern filament are also the densest (within 1100 AU) cores in OMC-1S. This is fully consistent with previous studies of fragmentation at spatial scales one order of magnitude larger, and suggests that fragmentation down to 40 AU seems to be governed by thermal Jeans processes in OMC-1S.Comment: Accepted to Ap

Peroxisome proliferator-activated receptor (PPAR)alpha expression in T cells mediates gender differences in development of T cell-mediated autoimmunity.

Peroxisome proliferator-activated receptor (PPAR)alpha is a nuclear receptor that mediates gender differences in lipid metabolism. PPARalpha also functions to control inflammatory responses by repressing the activity of nuclear factor kappaB (NF-kappaB) and c-jun in immune cells. Because PPARalpha is situated at the crossroads of gender and immune regulation, we hypothesized that this gene may mediate sex differences in the development of T cell-mediated autoimmune disease. We show that PPARalpha is more abundant in male as compared with female CD4(+) cells and that its expression is sensitive to androgen levels. Genetic ablation of this gene selectively removed the brake on NF-kappaB and c-jun activity in male T lymphocytes, resulting in higher production of interferon gamma and tumor necrosis factor (but not interleukin 17), and lower production of T helper (Th)2 cytokines. Upon induction of experimental autoimmune encephalomyelitis, male but not female PPARalpha(-/-) mice developed more severe clinical signs that were restricted to the acute phase of disease. These results suggest that males are less prone to develop Th1-mediated autoimmunity because they have higher T cell expression of PPARalpha

Propuesta de mejora en los procesos productivos de equipos metal mecánicos en una empresa metalmecanica mediana

El siguiente trabajo presenta la oportunidad de la aplicación de herramientas de ingeniería industrial en los procesos productivos de los equipos con mayor frecuencia de ventas en la compañía metalmecánica Tama Ingenieros S.A.C., con el fin de estandarizar su proceso de producción y mejorar, de ese modo, la eficiencia de la línea de producción de equipos estándar. En la actualidad, a pesar de la desaceleración de la economía, en particular en el sector minero, principal cliente de las empresas metalmecánicas, estas todavía tienen un mercado de productos para la ampliación y mantenimiento de las plantas de producción minera y de empresas anexas a ellas. Además, se tiene los nuevos mercados de proyectos de infraestructura, donde se tiene una oportunidad con las empresas anexas como las siderúrgicas. El presente trabajo busca incrementar la eficiencia del proceso de producción, de los productos que se fabrican con mayor frecuencia, utilizando alguna de las herramientas que proporciona la ingeniería industrial, lo cual se revertirá en mejorar la competitividad de la empresa, al contribuir en el análisis de costos, basándose en la eficiencia de los procesos. El trabajo, en su primer capítulo, proporciona un marco teórico que brinda los conceptos básicos relacionados a los procesos productivos, calidad total, los conceptos en los que se basa el desarrollo de la filosofía Kaizen y una breve descripción del método 5S. El segundo capítulo, brinda un análisis de la situación actual del sector metalmecánico, las oportunidades que ofrece y un horizonte de las inversiones relacionadas con este sector industrial. Así mismo, presenta un análisis de la situación actual de la compañía Tama Ingenieros S.A.C., el estado actual de sus procesos de fabricación, sus ratios y sus costos de fabricación. Todo esto con la finalidad de brindar un marco general y poder ubicarnos en el entorno de la compañía, e identificar las oportunidades de mejora. El tercer capítulo plantea dos diferentes metodologías que se pueden utilizar para revertir las oportunidades de mejora identificadas en el capítulo previo. En este caso, se presenta una comparación entre la Ingeniería de Métodos y el Kaizen y a través de una matriz de decisiones se opta por la metodología más adecuada para la solución del problema identificado: Kaizen. El capítulo desarrolla la implementación de la metodología seleccionada e incluye el cronograma de implementación. Finalmente, el cuarto y último capítulo presenta la simulación de la aplicación de la propuesta planteada así como el análisis financiero correspondiente.Tesi

Unit fractions in the context of proportionality: supporting students' reasoning about the inverse order relationship

We analyze a classroom design experiment, conducted in a fourth grade classroom, that served to explore an instructional path in which the introduction of unit fractions and supporting proportional reasoning coincide. Central to this path is the use of means of support in which the objects that unit fractions quantify are not characterized as equal-sized parts of a whole, but as entities that are always separate from a reference unit. We argue that such a path is crucial for helping students develop deep quantitative understandings of fractions, where fraction quantities are, from the very start, linked to the reciprocal and multiplicative relations that their use implies. We focus on the first part of the design experiment in which we helped the students make sense of a concept that is important for initial fraction learning and proportional reasoning, the inverse order relationship among unit fractions