Approximate performance analysis of generalized join the shortest queue routing

In this paper we propose a highly accurate approximate performance analysis of a heterogeneous server system with a processor sharing service discipline and a general job-size distribution under a generalized join the shortest queue (GJSQ) routing protocol. The GJSQ routing protocol is a natural extension of the well-known join the shortest queue routing policy that takes into account the non-identical service rates in addition to the number of jobs at each server. The performance metrics that are of interest here are the equilibrium distribution and the mean and standard deviation of the number of jobs at each server. We show that the latter metrics are near-insensitive to the job-size distribution using simulation experiments. By applying a single queue approximation we model each server as a single server queue with a state-dependent arrival process, independent of other servers in the system, and derive the distribution of the number of jobs at the server. These state-dependent arrival rates are intended to capture the inherent correlation between servers in the original system and behave in a rather atypical way.Comment: 16 pages, 5 figures -- version 2 incorporates minor textual change

Steady-state analysis of shortest expected delay routing

We consider a queueing system consisting of two non-identical exponential servers, where each server has its own dedicated queue and serves the customers in that queue FCFS. Customers arrive according to a Poisson process and join the queue promising the shortest expected delay, which is a natural and near-optimal policy for systems with non-identical servers. This system can be modeled as an inhomogeneous random walk in the quadrant. By stretching the boundaries of the compensation approach we prove that the equilibrium distribution of this random walk can be expressed as a series of product-forms that can be determined recursively. The resulting series expression is directly amenable for numerical calculations and it also provides insight in the asymptotic behavior of the equilibrium probabilities as one of the state coordinates tends to infinity.Comment: 41 pages, 13 figure

Extending the Apprenticeship of Observation: How Mentee Experience Shape Mentors

Although the importance of mentor teachers in clinical teacher preparation is well established, few researchers explore the social identity development of these individuals. Through our study we contribute to the body of research by exploring mentor teachers\u27 social identity development through the concept of Apprenticeship of Observation - specifically, how they felt their own mentoring experiences influenced their approaches to mentoring. The multi-case study includes findings about mentoring beliefs and practices during the laboratory school component of an Alternate Route to Licensure program. Incorporating semi-structured interviews and video analysis, the findings demonstrate how four mentor teachers\u27 prior experiences as mentees - including Alternate Route to Licensure, traditional teacher preparation programs, and inservice teaching - influenced their interactions with teacher candidates as mentors. Recommendations for practice and implications for future research are provided

Upaya Meningkatkan Hasil Belajar Passing Atas Bola Voli Menggunakan Media Bola Gantung Pada Siswa SMP Negeri Gudang Arang Merauke

This study aims to improve passing skills for volleyball by using hanging balls as a medium for class VIIIB students of Gudang Arang Merauke State Middle School. This research is a class action research conducted in 2 cycles, each cycle consisting of 2 meetings. Gudang Arang Merauke State, Jalan Pintu Air, Merauke. The subjects of this research were class VIIIB students of Gudang Arang Merauke State Middle School, totaling 23 students consisting of 11 male students and 12 female students. The data collection technique used in learning outcomes contained three aspects. namely: Affective assessment aspect format, worksheet, and psychomotor aspect assessment. In this study, the data analysis technique used was qualitative description analysis. Research skills show that using hanging ball media can improve learning outcomes of passing over volleyball in class VIIIB students of Gudang Arang Merauke Public Middle School, which is marked by increased student learning outcomes in each cycle. In cycle 1 the percentage of students who complete is 74% or 17 students completed experience an increase in cycle 2 value data 80% is 21 students or those who complete learning, then there is an increase of 91% in cycle 2 the increase in completeness from cycle I to cycle II is 91%Penelitian ini bertujuan untuk meningkatkan kemampuan passing atas bola voli dengan mengunakan media bola gantung pada siswa kelas VIIIB SMP Negeri Gudang Arang Merauke.penelitian ini merupakan penilitian tindakan kelas yang dilakukan dalam 2 siklus ,tiap siklus terdiri dari 2 kali  pertemuan.Tempat penilitian dilaksananakn di SMP Negeri Gudang Arang Merauke Jalan Pintu Air,Merauke.Subjek Penilitian ini adalah siswa kelas VIIIB SMP Negeri Gudang Arang Merauke yang berjumlah 23 Siswa yang terdiri dari 11 siswa laki-laki dan 12 perempuan.Teknik pengumpulan data yan g digunakan dalam hasil belajar terdapat tiga aspek yaitu : Fotmat aspek penilaian afektif,LKS,penilaian aspek psikomotor.Dalam penelitian ini teknik analisis data yang di gunakan adalah analisis deskripsi kualitatif.             Keterampilan penilitian menunjukan bahwa dengan media bola gantung  dapat meningkatkan hasil belajar passing  atas bola voli pada siswa kelas VIIIB SMP Negeri Gudang Arang  Merauke,yang ditandai dengan meningkatnya hasil belajar siswa pada tiap siklus.Pada  siklus 1 presentase siswa yang tuntas adalah 74% atau 17 siswa  tuntas mengalami peningkatan data nilai  siklus 2  91% adalah 21 siswa atau yang  tuntas belajar, maka ada penigkatan sebesar 91% pada siklus 2 peningkatan ketuntasan dari siklus I Ke siklus II adalah 91% &nbsp

Selection for resistance to oseltamivir in seasonal and pandemic H1N1 influenza and widespread co-circulation of the lineages

Background: In Spring 2009, a novel reassortant strain of H1N1 influenza A emerged as a lineage distinct from seasonal H1N1. On June 11, the World Heath Organization declared a pandemic - the first since 1968. There are currently two main branches of H1N1 circulating in humans, a seasonal branch and a pandemic branch. The primary treatment method for pandemic and seasonal H1N1 is the antiviral drug Tamiflu® (oseltamivir). Although many seasonal H1N1 strains around the world are resistant to oseltamivir, initially, pandemic H1N1 strains have been susceptible to oseltamivir. As of February 3, 2010, there have been reports of resistance to oseltamivir in 225 cases of H1N1 pandemic influenza. The evolution of resistance to oseltamivir in pandemic H1N1 could be due to point mutations in the neuraminidase or a reassortment event between seasonal H1N1 and pandemic H1N1 viruses that provide a neuraminidase carrying an oseltamivir-resistant genotype to pandemic H1N1. Results: Using phylogenetic analysis of neuraminidase sequences, we show that both seasonal and pandemic lineages of H1N1 are evolving to direct selective pressure for resistance to oseltamivir. Moreover, seasonal lineages of H1N1 that are resistant to oseltamivir co-circulate with pandemic H1N1 throughout the globe. By combining phylogenetic and geographic data we have thus far identified 53 areas of co-circulation where reassortment can occur. At our website POINTMAP, http://pointmap.osu.edu webcite we make available a visualization and an application for updating these results as more data are released. Conclusions: As oseltamivir is a keystone of preparedness and treatment for pandemic H1N1, the potential for resistance to oseltamivir is an ongoing concern. Reassortment and, more likely, point mutation have the potential to create a strain of pandemic H1N1 against which we have a reduced number of treatment options