Transportation and Distribution of Strategic National Stockpile Supplies in a Public Health Emergency

In the event of a public health emergency in the United States, it is important that public authorities are equipped to distribute medical supplies to every person in need as quickly as possible. Federal guidelines state that all persons in an area affected by a public health emergency should receive their medical countermeasures within 48 hours of the emergency’s declaration. While the CDC has determined a general dispensing plan for each state and county to follow, it is ultimately up to the state and county to formalize and implement detailed plans. A body of academic literature focuses on optimizing the placement and operation of Points of Dispensing (PODs), which are mass dispensing locations the public visits to receive countermeasures. However, very few papers have considered the logistics associated with moving countermeasures from state receiving areas to county-level PODs. This research addresses this gap through service network design and transportation modeling. Specifically, the feasibility of a multi-tiered distribution model is evaluated for a case study region representative of a US state comprised of a mix of urban and rural areas

Behavioural simulation of biological neuron systems using VHDL and VHDL-AMS

The investigation of neuron structures is an incredibly difficult and complex task that yields relatively low rewards in terms of information from biological forms (either animals or tissue). The structures and connectivity of even the simplest invertebrates are almost impossible to establish with standard laboratory techniques, and even when this is possible it is generally time consuming, complex and expensive. Recent work has shown how a simplified behavioural approach to modelling neurons can allow “virtual” experiments to be carried out that map the behaviour of a simulated structure onto a hypothetical biological one, with correlation of behaviour rather than underlying connectivity. The problems with such approaches are numerous. The first is the difficulty of simulating realistic aggregates efficiently, the second is making sense of the results and finally, it would be helpful to have an implementation that could be synthesised to hardware for acceleration. In this paper we present a VHDL implementation of Neuron models that allow large aggregates to be simulated. The models are demonstrated using a system level VHDL and VHDL-AMS model of the C. Elegans locomotory system

Modelica - A Language for Physical System Modeling, Visualization and Interaction

Modelica is an object-oriented language for modeling of large, complex and heterogeneous physical systems. It is suited for multi-domain modeling, for example for modeling of mechatronics including cars, aircrafts and industrial robots which typically consist of mechanical, electrical and hydraulic subsystems as well as control systems. General equations are used for modeling of the physical phenomena, No particular variable needs to be solved for manually. A Modelica tool will have enough information to do that automatically. The language has been designed to allow tools to generate efficient code automatically. The modeling effort is thus reduced considerably since model components can be reused and tedious and error-prone manual manipulations are not needed. The principles of object-oriented modeling and the details of the Modelica language as well as several examples are presented

Residual Z2 x Z2 symmetries and lepton mixing

We consider two novel scenarios of residual symmetries of the lepton mass matrices. Firstly we assume a Z2 x Z2 symmetry G_ell for the charged-lepton mass matrix and a Z2 symmetry G_nu for the light neutrino mass matrix. With this setting, the moduli of the elements of one column of the lepton mixing matrix are fixed up to a reordering. One may interchange the roles of G_ell and G_nu in this scenario, thereby constraining a row, instead of a column, of the mixing matrix. Secondly we assume a residual symmetry group G_ell \cong Zm (m>2) which is generated by a matrix with a doubly-degenerate eigenvalue. Then, with G_nu \cong Z2 x Z2 the moduli of the elements of a row of the lepton mixing matrix get fixed. Using the library of small groups we have performed a search for groups which may embed G_ell and G_nu in each of these two scenarios. We have found only two phenomenologically viable possibilities, one of them constraining a column and the other one a row of the mixing matrix.Comment: 14 pages, 1 figur

DIVERSE: a Software Toolkit to Integrate Distributed Simulations with Heterogeneous Virtual Environments

We present DIVERSE (Device Independent Virtual Environments- Reconfigurable, Scalable, Extensible), which is a modular collection of complimentary software packages that we have developed to facilitate the creation of distributed operator-in-the-loop simulations. In DIVERSE we introduce a novel implementation of remote shared memory (distributed shared memory) that uses Internet Protocol (IP) networks. We also introduce a new method that automatically extends hardware drivers (not in the operating system kernel driver sense) into inter-process and Internet hardware services. Using DIVERSE, a program can display in a CAVE™, ImmersaDesk™, head mounted display (HMD), desktop or laptop without modification. We have developed a method of configuring user programs at run-time by loading dynamic shared objects (DSOs), in contrast to the more common practice of creating interpreted configuration languages. We find that by loading DSOs the development time, complexity and size of DIVERSE and DIVERSE user applications is significantly reduced. Configurations to support different I/O devices, device emulators, visual displays, and any component of a user application including interaction techniques, can be changed at run-time by loading different sets of DIVERSE DSOs. In addition, interpreted run-time configuration parsers have been implemented using DIVERSE DSOs; new ones can be created as needed. DIVERSE is free software, licensed under the terms of the GNU General Public License (GPL) and the GNU Lesser General Public License (LGPL) licenses. We describe the DIVERSE architecture and demonstrate how DIVERSE was used in the development of a specific application, an operator-in-the-loop Navy ship-board crane simulator, which runs unmodified on a desktop computer and/or in a CAVE with motion base motion queuing

Practical Modelling of Trip Rescheduling under Congested Conditions

There is plenty of anecdotal evidence that drivers may make small changes in their time of travel to take advantage of lower levels of congestion. However, progress in modelling such “micro” re-scheduling within peak period traffic remains slow. While there exist research papers describing theoretical solutions, there are no techniques available for practical use. Most commonly used assignment programs are temporally aggregate, while packages which do allow some “dynamic assignment” typically assume a fixed demand profile. The aim of the paper is to present a more heuristic method which could at least be used on an interim basis. The assumption is that the demand profile can be demanded into a number of mutually exclusive “windows” in relation to the “preferred arrival time”, while on the assignment side, independently defined sequential “timeslices” are used in order to respect some of the dynamic processes relating to the build-up of queues. The demand process, whereby some drivers shift away from their preferred window, leads to an iterative procedure with the aim of achieving reasonable convergence. Using the well-known scheduling theory developed by Vickrey, Small, and Arnott, de Palma & Lindsey, the basic approach can be described, extending from the simple “bottleneck”, to which the theory was originally applied, to a general network. So far, insufficient research funds have been made available to test the approach properly. It is hoped that by bringing the ideas into the public domain, further research into this area may be stimulated.