Next Generation Emergency Call System with Enhanced Indoor Positioning

The emergency call systems in the United States and elsewhere are undergoing a transition from the PSTN-based legacy system to a new IP-based system. The new system is referred to as the Next Generation 9-1-1 (NG9-1-1) or NG112 system. We have built a prototype NG9-1-1 system which features media convergence and data integration that are unavailable in the current emergency calling system. The most important piece of information in the NG9-1-1 system is the caller's location. The caller's location is used for routing the call to the appropriate call center. The emergency responders use the caller's location to find the caller. Therefore, it is essential to determine the caller's location as precisely as possible to minimize delays in emergency response. Delays in response may result in loss of lives. When a person makes an emergency call outdoors using a mobile phone, the Global Positioning System (GPS) can provide the caller's location accurately. Indoor positioning, however, presents a challenge. GPS does not generally work indoors because satellite signals do not penetrate most buildings. Moreover, there is an important difference between determining location outdoors and indoors. Unlike outdoors, vertical accuracy is very important in indoor positioning because an error of few meters will send emergency responders to a different floor in a building, which may cause a significant delay in reaching the caller. This thesis presents a way to augment our NG9-1-1 prototype system with a new indoor positioning system. The indoor positioning system focuses on improving the accuracy of vertical location. Our goal is to provide floor-level accuracy with minimum infrastructure support. Our approach is to use a user's smartphone to trace her vertical movement inside buildings. We utilize multiple sensors available in today's smartphones to enhance positioning accuracy. This thesis makes three contributions. First, we present a hybrid architecture for floor localization with emergency calls in mind. The architecture combines beacon-based infrastructure and sensor-based dead reckoning, striking a balance between accurately determining a user's location and minimizing the required infrastructure. Second, we present the elevator module for tracking a user's movement in an elevator. The elevator module addresses three core challenges that make it difficult to accurately derive displacement from acceleration. Third, we present the stairway module which determines the number of floors a user has traveled on foot. Unlike previous systems that track users' foot steps, our stairway module uses a novel landing counting technique. Additionally, this thesis presents our work on designing and implementing an NG9-1-1 prototype system. We first demonstrate how emergency calls from various call origination devices are identified, routed to the proper Public Safety Answering Point (PSAP) based on the caller's location, and terminated by the call taker software at the PSAP. We then show how text communications such as Instant Messaging and Short Message Service can be integrated into the NG9-1-1 architecture. We also present GeoPS-PD, a polygon simplification algorithm designed to improve the performance of location-based routing. GeoPS-PD reduces the size of a polygon, which represents the service boundary of a PSAP in the NG9-1-1 system

Improving the Vertical Accuracy of Indoor Positioning for Emergency Communication

The emergency communication systems are undergoing a transition from the PSTN-based legacy system to an IP-based next generation system. In the next generation system, GPS accurately provides a user's location when the user makes an emergency call outdoors using a mobile phone. Indoor positioning, however, presents a challenge because GPS does not generally work indoors. Moreover, unlike outdoors, vertical accuracy is critical indoors because an error of few meters will send emergency responders to a different floor in a building. This paper presents an indoor positioning system which focuses on improving the accuracy of vertical location. We aim to provide floor-level accuracy with minimal infrastructure support. Our approach is to use multiple sensors available in today's smartphones to trace users' vertical movements inside buildings. We make three contributions. First, we present the elevator module for tracking a user's movement in elevators. The elevator module addresses three core challenges that make it difficult to accurately derive displacement from acceleration. Second, we present the stairway module which determines the number of floors a user has traveled on foot. Unlike previous systems that track users' foot steps, our stairway module uses a novel landing counting technique. Third, we present a hybrid architecture that combines the sensor-based components with minimal and practical infrastructure. The infrastructure provides initial anchor and periodic corrections of a user's vertical location indoors. The architecture strikes the right balance between the accuracy of location and the feasibility of deployment for the purpose of emergency communication

Finding 9-1-1 Callers in Tall Buildings

Accurately determining a user’s floor location is essential for minimizing delays in emergency response. This paper presents a floor localization system intended for emergency calls. We aim to provide floor-level accuracy with minimum infrastructure support. Our approach is to use multiple sensors, all available in today’s smartphones, to trace a user’s vertical movements inside buildings. We make three contributions. First, we present a hybrid architecture for floor localization with emergency calls in mind. The architecture combines beacon-based infrastructure and sensor-based dead reckoning, striking the right balance between accurately determining a user’s location and minimizing the required infrastructure. Second, we present the elevator module for tracking a user’s movement in an elevator. The elevator module addresses three core challenges that make it difficult to accurately derive displacement from acceleration. Third, we present the stairway module which determines the number of floors a user has traveled on foot. Unlike previous systems that track users’ foot steps, our stairway module uses a novel landing counting technique

NetServ: Reviving Active Networks

In 1996, Tennenhouse and Wetherall proposed active networks, where users can inject code modules into network nodes. The proposal sparked intense debate and follow-on research, but ultimately failed to win over the networking community. Fifteen years later, the problems that motivated the active networks proposal persist. We call for a revival of active networks. We present NetServ, a fully integrated active network system that provides all the necessary functionality to be deployable, addressing the core problems that prevented the practical success of earlier approaches. We make the following contributions. We present a hybrid approach to active networking, which combines the best qualities from the two extreme approaches — integrated and discrete. We built a working system that strikes the right balance between security and performance by leveraging current technologies. We suggest an economic model based on NetServ between content providers and ISPs. We built four applications to illustrate the model

Capacitive Heart-Rate Sensing on Touch Screen Panel with Laterally Interspaced Electrodes

It is demonstrated that the heart-rate can be sensed capacitively on a touch screen panel (TSP) together with touch signals. The existing heart-rate sensing systems measure blood pulses by tracing the amount of light reflected from blood vessels during a number of cardiac cycles. This type of sensing system requires a considerable amount of power and space to be implemented in multi-functional mobile devices such as smart phones. It is found that the variation of the effective dielectric constant of finger stemming from the difference of systolic and diastolic blood flows can be measured with laterally interspaced top electrodes of TSP. The spacing between a pair of non-adjacent top electrodes turns out to be wide enough to distinguish heart-rate signals from noises. With the aid of fast Fourier transform, the heart-rate can be extracted reliably, which matches with the one obtained by actually counting heart beats on the wrist

NetServ Framework Design and Implementation 1.0

Eyeball ISPs today are under-utilizing an important asset: edge routers. We present NetServ, a programmable node architecture aimed at turning edge routers into distributed service hosting platforms. This allows ISPs to allocate router resources to content publishers and application service pro\-vi\-ders motivated to deploy content and services at the network edge. This model provides important benefits over currently available solutions like CDN. Content and services can be brought closer to end users by dynamically installing and removing custom modules as needed throughout the network. Unlike previous programmable router proposals which focused on customizing features of a router, NetServ focuses on deploying content and services. All our design decisions reflect this change in focus. We set three main design goals: a wide-area deployment, a multi-user execution environment, and a clear economic benefit. We built a prototype using Linux, NSIS signaling, and the Java OSGi framework. We also implemented four prototype applications: ActiveCDN provides publisher-specific content distribution and processing; KeepAlive Responder and Media Relay reduce the infrastructure needs of telephony providers; and Overload Control makes it possible to deploy more flexible algorithms to handle excessive traffic

Polygon Simplification for Location-Based Services Using Population Density

An important group of location-based services (LBS), including 9-1-1 service, rely on the mapping between a user’s location and a service boundary in order to select the appropriate service provider. In such cases, mobile clients can cache the mapping information to reduce service latency and server load. However, caching such a mapping can be burdensome on mobile devices because representing the polygon that defines a service boundary requires a large amount of data. We present GeoPS-PD, a polygon simplification algorithm designed for LBS applications. Unlike existing algorithms, GeoPS-PD never produces a false positive, is tunable at runtime for the desired balance between target polygon size and area coverage, and optionally takes into account the population density. We demonstrate the efficacy of GeoPS-PD using the US state boundary data. For New York, GeoPS-PD produces a simplified polygon which is only 3 % of the original size, yet covers 95 % of the original area, and makes the LBS queries 3.17 times faster

Polygon Simplification for Location-Based Services Using Population Density

Abstract—An important group of location-based services (LBS), including 9-1-1 service, rely on the mapping between a user’s location and a service boundary in order to select the appropriate service provider. In such cases, mobile clients can cache the mapping information to reduce service latency and server load. However, caching such a mapping can be burdensome on mobile devices because representing the polygon that defines a service boundary requires a large amount of data. We present GeoPS-PD, a polygon simplification algorithm designed for LBS applications. Unlike existing algorithms, GeoPS-PD never produces a false positive, is tunable at runtime for the desired balance between target polygon size and area coverage, and optionally takes into account the population density. We demonstrate the efficacy of GeoPS-PD using the US state boundary data. For New York, GeoPS-PD produces a simplified polygon which is only 3 % of the original size, yet covers 95 % of the original area, and makes the LBS queries 3.17 times faster. I