How to Staff when Customers Arrive in Batches

In settings as diverse as autonomous vehicles, cloud computing, and pandemic quarantines, requests for service can arrive in near or true simultaneity with one another. This creates batches of arrivals to the underlying queueing system. In this paper, we study the staffing problem for the batch arrival queue. We show that batches place a significant stress on services, and thus require a high amount of resources and preparation. In fact, we find that there is no economy of scale as the number of customers in each batch increases, creating a stark contrast with the square root safety staffing rules enjoyed by systems with solitary arrivals of customers. Furthermore, when customers arrive both quickly and in batches, an economy of scale can exist, but it is weaker than what is typically expected. Methodologically, these staffing results follow from novel large batch and hybrid large-batch-and-large-rate limits of the general multi-server queueing model. In the pure large batch limit, we establish the first formal connection between multi-server queues and storage processes, another family of stochastic processes. By consequence, we show that the limit of the batch scaled queue length process is not asymptotically normal, and that, in fact, the fluid and diffusion-type limits coincide. This is what drives our staffing analysis of the batch arrival queue, and what implies that the (safety) staffing of this system must be directly proportional to the batch size just to achieve a non-degenerate probability of customers waiting

Person-to-Person Lending: The Pursuit of (More) Competitive Credit Markets

Person-to-person lending (P2PL) on the Internet is a relatively new credit market. The success of these markets hinges on their ability to provide both borrowers and lenders the chance to improve on the opportunities available in traditional intermediated credit markets. In essence, P2PL must create a more competitive market. Empirical observations provide evidence that frictions exist in these markets, which generally move markets away from competitive outcomes. Currently, auctions are the most popular mechanism for P2PL. This paper develops and analyzes an equilibrium competing auction model of P2PL. Coordination frictions and the presence of non-creditworthy borrowers create an environment where many potentially productive transactions are not made and interest rate dispersion is observed. Additionally, if the market naturally segments into groups of similar borrowers then increased frictions in a segment may lead some portion of lenders to migrate to a different segment

New Hampshire rural towns\u27 comparative road burdens and road services, Bulletin, no. 339

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire

Pocket Guide to Transportation 2023

The BTS Pocket Guide to Transportation is a quick reference guide that provides transportation statistics at your fingertips. It provides key information and highlights major trends on the U.S. transportation system. Intended as a compact reference, the Pocket Guide supports the BTS mission to create, manage, and share transportation statistical knowledge

Predictors of residential stability among homeless young adults : a cohort study.

Abstract : BACKGROUND: Homelessness episodes have been shown to be associated with serious health outcomes among youth. This study was undertaken to estimate the probability of reaching residential stability over time and to identify predictors of residential stability among homeless young adults aged 18 to 25 years. METHODS: A prospective cohort study was carried out in Montréal, Canada, between April 5(th) 2006 and January 21(th) 2009. Interviews conducted every three months included questions on life conditions and social and mental health factors that are known to influence residential trajectories. Residential status was determined, starting on the first day after recruitment; each follow-up day was classified as a homeless day or a housed day. A period of 90 days was used to define residential stability; therefore the main study outcome was the occurrence of the first consecutive 90 housed days during the follow-up period. Kaplan-Meier and Cox proportional-hazards regression analyses were conducted. RESULTS: Of the 359 participants, 284 reached 90 days of residential stability over the study period, representing an annual probability of 80.5 %. In multivariate analysis, youth who had a high school degree, had a formal sector activity, and those who had sought psychological help were more likely to reach residential stability. Being a man, injecting substances, and having an informal sector activity were associated with a decreased probability to reach residential stability. CONCLUSION: Exposure to factors related to opportunities that promote social integration increases the chance of reaching residential stability. On the other hand, factors related to high level of street entrenchment seem to interfere with stabilization. Maximum efforts should be made to prevent chronic homelessness among youth, targeting not only individual impairments but also hinging on services adapted to foster social connections among the youth

Contrasting Transcriptional Responses of a Virulent and an Attenuated Strain of Mycobacterium tuberculosis Infecting Macrophages

Along with the recent identification of single nucleotide polymorphisms in H37Ra when compared to H37Rv, our demonstration of differential expression of PhoP-regulated and ESX-1 region-related genes during macrophage infection further highlights the significance of these genes in the attenuation of H37Ra

Challenges and opportunities for conducting a vaccine trial during the COVID-19 pandemic in the United Kingdom

The COVID-19 pandemic has resulted in unprecedented challenges for healthcare systems worldwide. It has also stimulated research in a wide range of areas including rapid diagnostics, novel therapeutics, use of technology to track patients and vaccine development. Here, we describe our experience of rapidly setting up and delivering a novel COVID-19 vaccine trial, using clinical and research staff and facilities in three National Health Service Trusts in Cambridgeshire, United Kingdom. We encountered and overcame a number of challenges including differences in organisational structures, research facilities available, staff experience and skills, information technology and communications infrastructure, and research training and assessment procedures. We overcame these by setting up a project team that included key members from all three organisations that met at least daily by teleconference. This group together worked to identify the best practices and procedures and to harmonise and cascade these to the wider trial team. This enabled us to set up the trial within 25 days and to recruit and vaccinate the participants within a further 23 days. The lessons learned from our experiences could be used to inform the conduct of clinical trials during a future infectious disease pandemic or public health emergency