Packet reordering, high speed networks and transport protocol performance

We performed end-to-end measurements of UDP/IP flows across an Internet backbone network. Using this data, we characterized the packet reordering processes seen in the network. Our results demonstrate the high prevalence of packet reordering relative to packet loss, and show a strong correlation between packet rate and reordering on the network we studied. We conclude that, given the increased parallelism in modern networks and the demands of high performance applications, new application and protocol designs should treat packet reordering on an equal footing to packet loss, and must be robust and resilient to both in order to achieve high performance

Surveying the Scope of the SU(2)_L Scalar Septet Sector

Extending the Standard Model by adding a scalar field transforming as a septet under $SU(2)_L$ preserves the $\rho$ parameter at tree level and can satisfy experimental constraints on the electroweak parameters $S$ and $T$. This work presents the first fully general phenomenological study of such an extension. We examine constraints on the septet model couplings based on electroweak and Higgs observables, and use LHC searches for new physics to bound the mass of the septet to be above $\sim 400$ GeV at a $95\%$ CL.Comment: pdfLateX, 17 pages, 6 figures, reference added. Version published in JHE

Quantum Walks of SU(2)_k Anyons on a Ladder

We study the effects of braiding interactions on single anyon dynamics using a quantum walk model on a quasi-1-dimensional ladder filled with stationary anyons. The model includes loss of information of the coin and nonlocal fusion degrees of freedom on every second time step, such that the entanglement between the position states and the exponentially growing auxiliary degrees of freedom is lost. The computational complexity of numerical calculations reduces drastically from the fully coherent anyonic quantum walk model, allowing for relatively long simulations for anyons which are spin-1/2 irreps of SU(2)_k Chern-Simons theory. We find that for Abelian anyons, the walk retains the ballistic spreading velocity just like particles with trivial braiding statistics. For non-Abelian anyons, the numerical results indicate that the spreading velocity is linearly dependent on the number of time steps. By approximating the Kraus generators of the time evolution map by circulant matrices, it is shown that the spatial probability distribution for the k=2 walk, corresponding to Ising model anyons, is equal to the classical unbiased random walk distribution.Comment: 12 pages, 4 figure

Experiences with high definition interactive video conferencing

We review the design and implementation of UltraGrid, a new high definition video conferencing system, and present some experimental results. UltraGrid was the first system to support gigabit rate high definition interactive video conferencing on commodity systems and networks, and we present measurements to illustrate behavior of production networks subject to such real time traffic. We illustrate the benefits of hybrid IP/provisioned optical networks over best effort IP networks for this class of traffic, and motivate the development of congestion control algorithms for interactive conferencing on best effort IP networks

Assessing statistical significance of periodogram peaks

The least-squares (or Lomb-Scargle) periodogram is a powerful tool which is used routinely in many branches of astronomy to search for periodicities in observational data. The problem of assessing statistical significance of candidate periodicities for different periodograms is considered. Based on results in extreme value theory, improved analytic estimations of false alarm probabilities are given. They include an upper limit to the false alarm probability (or a lower limit to the significance). These estimations are tested numerically in order to establish regions of their practical applicability.Comment: 7 pages, 6 figures, 1 table; To be published in MNRA

Multicultural Competence: A Literature Review Supporting Focused Training for Preservice Teachers Teaching Diverse Students

This paper focuses on an in depth literature review based on preservice teachers perceptions of their multicultural competence in teaching diverse students. More specifically, the literature review was framed around findings from a study looking at the gap between increased diversity of students and the level of multicultural competence of preservice teachers at a local university was investigated in this qualitative case study. Inductive data analysis results indicated that preservice teachers perceived a need for additional multicultural competence including increased awareness, knowledge, and skills in working with diverse students. A professional development training workshop design was created to address four dominant themes from the analysis.  The literature review supports the prominent components addressed by the professional development training workshop. Adequately preparing preservice teachers for teaching  diverse students continues as a focus in teacher preparation programs. As a faculty member at the local university, school of education, ongoing research focused on building preservice teachers multicultural competence remains essential. Keywords: multicultural competence, diverse students, preservice teacher, awareness, knowledge, skills

The role of optimization in structural model refinement

To evaluate the role that optimization can play in structural model refinement, it is necessary to examine the existing environment for the structural design/structural modification process. The traditional approach to design, analysis, and modification is illustrated. Typically, a cyclical path is followed in evaluating and refining a structural system, with parallel paths existing between the real system and the analytical model of the system. The major failing of the existing approach is the rather weak link of communication between the cycle for the real system and the cycle for the analytical model. Only at the expense of much human effort can data sharing and comparative evaluation be enhanced for the two parallel cycles. Much of the difficulty can be traced to the lack of a user-friendly, rapidly reconfigurable engineering software environment for facilitating data and information exchange. Until this type of software environment becomes readily available to the majority of the engineering community, the role of optimization will not be able to reach its full potential and engineering productivity will continue to suffer. A key issue in current engineering design, analysis, and test is the definition and development of an integrated engineering software support capability. The data and solution flow for this type of integrated engineering analysis/refinement system is shown

Resilience and Depressive Symptoms in Midlife Women

Rates of depression are increasing throughout the world, with women experiencing depression twice as often as men. This study utilized the Neuman Systems Model to examine the relationship in midlife women between depressive symptoms and resilience. Women ages 35-55, selected from four health care settings, completed written surveys on demographic information, life events, depression, and resilience. Results supported depressive symptoms as a health concern for mid-life women: 32% reporting current or previous treatment for depression, and 24% screening positive for depression. Resilience, measured by the Polk Resilience Patterns Scale, was related to education, perceived health, conflict in the living situation, and financial resources. It was inversely correlated with depressive symptoms. Depressive symptoms were related to perceived health, conflict in the living situation, financial resources, and sleep. Negative life events and the situational and philosophical resilience subscales contributed to 64% of the variance in the measure of depressive symptoms

RT_BUILD: An expert programmer for implementing and simulating Ada real-time control software

The RT BUILD is an expert control system programmer that creates real-time Ada code from block-diagram descriptions of control systems. Since RT BUILD embodies substantial knowledge about the implementation of real-time control systems, it can perform many, if not most of the functions normally performed by human real-time programmers. Though much basic research was done in automatic programming, RT BUILD appears to be the first application of this research to an important problem in flight control system development. In particular, RT BUILD was designed to directly increase productivity and reliability for control implementations of large complex systems