Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts

The present invention is generally directed to a system for monitoring a variety of environmental and/or other conditions within a defined remotely located region. In one aspect, a system is configured to monitor utility meters (613) in a defined area. The system is implemented by using a plurality of wireless transmitters (614), each integrated into a sensor (612) adapted to monitor a particular data input. The system also includes a plurality of transceivers (221) that are dispersed throughout the region at defined locations. The system uses a local gateway (210) to translate and transfer information from the transmitters to a dedicated computer (260) on a network (230). The dedicated computer collects, compiles and stores the data for retrieval upon client demand across the network. The computer further includes means for evaluating the received information and identifying an appropriate control signal to be applied at a designated actuator.

System and method for monitoring and controlling remote devices

Concern about the performance of wires wires in scaled technologies has led to research exploring other communication methods. This paper examines wire and gate delays as technologies migrate from 0.18-/spl mu/m to 0.035-/spl mu/m feature sizes to better understand the magnitude of the the wiring problem. Wires that shorten in length as technologies scale have delays that either track gate delays or grow slowly relative to gate delays. This result is good news since these "local" wires dominate chip wiring. Despite this scaling of local wire performance, computer-aided design (CAD) tools must still become move sophisticated in dealing with these wires. Under scaling, the total number of wires grows exponentially, so CAD tools will need to handle an ever-growing percentage of all the wires in order to keep designer workloads constant. Global wires present a more serious problem to designers. These are wires that do not scale in length since they communicate signals across the chip. The delay of these wives will remain constant if repeaters are used meaning that relative to gate delays, their delays scale upwards. These increased delays for global communication will drive architectures toward modular designs with explicit global latency mechanisms.

The future of wires

The IEEE 802.11 Wireless LAN standards allow multiple non-overlapping frequency channels to be used simultaneously to increase the aggregate bandwidth available to end-users. Such bandwidth aggregation capability is routinely used in infrastructure mode operation, where the traffic to and from wireless nodes is distributed among multiple interfaces of an access point or among multiple access points to balance the traffic load. However, bandwidth aggregation is rarely used in the context of multi-hop 802.11-based LANs that operate in the ad hoc mode. Most past research efforts that attempt to exploit multiple radio channels require modifications to the MAC protocol and therefore do not work with commodity 802.11 interface hardware. In this paper, we propose and evaluate one of the first multi-channel multi-hop wireless ad-hoc network architectures that can be built using standard 802.11 hardware by equipping each node with multiple network interface cards (NICs) operating on different channels. We focus our attention on wireless mesh networks that serve as the backbone for relaying end-user traffic from wireless access points to the wired network. The idea of exploiting multiple channels is particularly appealing in wireless mesh networks because of their high capacity requirements to support backbone traffic. To reap the full performance potential of this architecture, we develop a set of centralized channel assignment, bandwidth allocation, and routing algorithms for multi-channel wireless mesh networks. A detailed performance evaluation shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture.

Centralized channel assignment and routing algorithms for multi-channel wireless mesh networks


               Summary
               
                  Background
                  Isolation of cases and contact tracing is used to control outbreaks of infectious diseases, and has been used for coronavirus disease 2019 (COVID-19). Whether this strategy will achieve control depends on characteristics of both the pathogen and the response. Here we use a mathematical model to assess if isolation and contact tracing are able to control onwards transmission from imported cases of COVID-19.
               
               
                  Methods
                  We developed a stochastic transmission model, parameterised to the COVID-19 outbreak. We used the model to quantify the potential effectiveness of contact tracing and isolation of cases at controlling a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-like pathogen. We considered scenarios that varied in the number of initial cases, the basic reproduction number (R
                     0), the delay from symptom onset to isolation, the probability that contacts were traced, the proportion of transmission that occurred before symptom onset, and the proportion of subclinical infections. We assumed isolation prevented all further transmission in the model. Outbreaks were deemed controlled if transmission ended within 12 weeks or before 5000 cases in total. We measured the success of controlling outbreaks using isolation and contact tracing, and quantified the weekly maximum number of cases traced to measure feasibility of public health effort.
               
               
                  Findings
                  Simulated outbreaks starting with five initial cases, an R
                     0 of 1·5, and 0% transmission before symptom onset could be controlled even with low contact tracing probability; however, the probability of controlling an outbreak decreased with the number of initial cases, when R
                     0 was 2·5 or 3·5 and with more transmission before symptom onset. Across different initial numbers of cases, the majority of scenarios with an R
                     0 of 1·5 were controllable with less than 50% of contacts successfully traced. To control the majority of outbreaks, for R
                     0 of 2·5 more than 70% of contacts had to be traced, and for an R
                     0 of 3·5 more than 90% of contacts had to be traced. The delay between symptom onset and isolation had the largest role in determining whether an outbreak was controllable when R
                     0 was 1·5. For R
                     0 values of 2·5 or 3·5, if there were 40 initial cases, contact tracing and isolation were only potentially feasible when less than 1% of transmission occurred before symptom onset.
               
               
                  Interpretation
                  In most scenarios, highly effective contact tracing and case isolation is enough to control a new outbreak of COVID-19 within 3 months. The probability of control decreases with long delays from symptom onset to isolation, fewer cases ascertained by contact tracing, and increasing transmission before symptoms. This model can be modified to reflect updated transmission characteristics and more specific definitions of outbreak control to assess the potential success of local response efforts.
               
               
                  Funding
                  Wellcome Trust, Global Challenges Research Fund, and Health Data Research UK.
               
            

The most radical of the architectures that appear in this issue are Raw processors-highly parallel architectures with hundreds of very simple processors coupled to a small portion of the on-chip memory. Each processor, or tile, also contains a small bank of configurable logic, allowing synthesis of complex operations directly in configurable hardware. Unlike the others, this architecture does not use a traditional instruction set architecture. Instead, programs are compiled directly onto the Raw hardware, with all units told explicitly what to do by the compiler. The compiler even schedules most of the intertile communication. The real limitation to this architecture is the efficacy of the compiler. The authors demonstrate impressive speedups for simple algorithms that lend themselves well to this architectural model, but whether this architecture will be effective for future workloads is an open question.

Baring it all to software: Raw machines

Increasing demand for both greater parallelism and faster clocks dictate that future generation architectures will need to decentralize their resources and eliminate primitives that require single cycle global communication. A Raw microprocessor distributes all of its resources, including instruction streams, register files, memory ports, and ALUs, over a pipelined two-dimensional mesh interconnect, and exposes them fully to the compiler. Because communication in Raw machines is distributed, compiling for instruction-level parallelism (ILP) requires both spatial instruction partitioning as well as traditional temporal instruction scheduling. In addition, the compiler must explicitly manage all communication through the interconnect, including the global synchronization required at branch points. This paper describes RAWCC, the compiler we have developed for compiling general-purpose sequential programs to the distributed Raw architecture. We present performance results that demonstrate that although Raw machines provide no mechanisms for global communication the Raw compiler can schedule to achieve speedups that scale with the number of available functional units.

/pdf/space-time-scheduling-of-instruction-level-parallelism-on-a-4j0j8yfj5q.pdf

Space-time scheduling of instruction-level parallelism on a raw machine

The invention includes an apparatus and method for determining an optimal route based upon path quality of routes to an access node of a wireless mesh network. The method includes receiving routing packets at the access node through at least one wireless route. Each routing packet including route information that identifies the wireless route of the routing packet. A success ration of a number of successfully received routing packets versus a number of transmitted routing packets is determined over a time Tl, for each wireless route. The wireless route having a greatest success ration is first selected, as are other wireless routes that have success rations within a predetermined amount of greatest success ratio. Of the first selected routes, routing packets are at the access node through the first selected routes. Again, each routing packet including route information that identifies the wireless route of the routing packet.

Selection of routing paths based upon path quality of a wireless mesh network

A method and apparatus for generating connectivity is described. The method includes a server broadcasting a beacon including the server's address. The method further includes each client that receives the beacon rebroadcasting the beacon. The result is that each client receiving the beacon knows a way to reach the server.

Method and apparatus to provide a routing protocol for wireless devices

Disclosed is an apparatus and method of client device roaming from a home subnet to a foreign subnet of a network. The method includes the client device accessing the network through a first access node of the home subnet, and the client device roaming to a second access node of the foreign subnet, the client device accessing the network through the second access node, the client device maintaining a fixed client IP address, default gateway IP address and IP subnet attachment as the client device roams from the first access node to the second access node.

Devabhaktuni Srikrishna

Papers

Baring it all to software: Raw machines

Space-time scheduling of instruction-level parallelism on a raw machine

Selection of routing paths based upon path quality of a wireless mesh network

Method and apparatus to provide a routing protocol for wireless devices

Method of subnet roaming within a network