"A Survey of Mobility Models for Ad Hoc Network Research," Wireless Comm. & Mobile Computing (WCMC) : Special issue on Mobile Ad Hoc Networking : Research

In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models that are used in the simulations of ad hoc networks. We describe several mobility models that represent mobile nodes whose movements are independent of each other (i.e., entity mobility models) and several mobility models that represent mobile nodes whose movements are dependent on each other (i.e., group mobility models). The goal of this paper is to present a number of mobility models in order to offer researchers more informed choices when they are deciding upon a mobility model to use in their performance evaluations. Lastly, we present simulation results that illustrate the importance of choosing a mobility model in the simulation of an ad hoc network protocol. Specifically, we illustrate how the performance results of an ad hoc network protocol drastically change as a result of changing the mobility model simulated.

/pdf/a-survey-of-mobility-models-for-ad-hoc-network-research-ygkxat400x.pdf

A survey of mobility models for ad hoc network research

We study the problem of searching on data that is encrypted using a public key system. Consider user Bob who sends email to user Alice encrypted under Alice’s public key. An email gateway wants to test whether the email contains the keyword “urgent” so that it could route the email accordingly. Alice, on the other hand does not wish to give the gateway the ability to decrypt all her messages. We define and construct a mechanism that enables Alice to provide a key to the gateway that enables the gateway to test whether the word “urgent” is a keyword in the email without learning anything else about the email. We refer to this mechanism as Public Key Encryption with keyword Search. As another example, consider a mail server that stores various messages publicly encrypted for Alice by others. Using our mechanism Alice can send the mail server a key that will enable the server to identify all messages containing some specific keyword, but learn nothing else. We define the concept of public key encryption with keyword search and give several constructions.

https://link.springer.com/content/pdf/10.1007%2F978-3-540-24676-3_30.pdf

Public Key Encryption with Keyword Search

We consider routing security in wireless sensor networks. Many sensor network routing protocols have been proposed, but none of them have been designed with security as a goal. We propose security goals for routing in sensor networks, show how attacks against ad-hoc and peer-to-peer networks can be adapted into powerful attacks against sensor networks, introduce two classes of novel attacks against sensor networks sinkholes and HELLO floods, and analyze the security of all the major sensor network routing protocols. We describe crippling attacks against all of them and suggest countermeasures and design considerations. This is the first such analysis of secure routing in sensor networks.

/pdf/secure-routing-in-wireless-sensor-networks-attacks-and-4630unozk9.pdf

Secure routing in wireless sensor networks: attacks and countermeasures

As sensor networks edge closer towards wide-spread deployment, security issues become a central concern. So far, much research has focused on making sensor networks feasible and useful, and has not concentrated on security.We present a suite of security building blocks optimized for resource-constrained environments and wireless communication. SPINS has two secure building blocks: SNEP and mTESLA SNEP provides the following important baseline security primitives: Data confidentiality, two-party data authentication, and data freshness. A particularly hard problem is to provide efficient broadcast authentication, which is an important mechanism for sensor networks. mTESLA is a new protocol which provides authenticated broadcast for severely resource-constrained environments. We implemented the above protocols, and show that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we demonstrate that the suite can be used for building higher level protocols.

http://www.csl.mtu.edu/cs5461/www/Reading/Perrig02.pdf

SPINS: security protocols for sensor networks

This installment of Notes from the Community covers new developments in interaction toolkits and platforms, security and privacy, smartphones, power consumption and battery life, and ubicomp education. It also includes a vision of ubicomp's past and future and presents works in progress on behavioral change.

Interaction Platforms, Energy Conservation, Behavior Change Research, and More

We would like to provide high-quality video conferencing so that people can communicate comfortably with each other anywhere, anytime. This is not a new goal, and there are now several applications such as Skype™ and FaceTime™ on mobile platforms that bring us closer to achieving anywhere, anytime video communications. Alas, these mobile conferences are often of poor quality due to the many challenges presented by mobile devices, such as constrained networks, limited processing power, small displays, and uncontrolled view angles and lighting. These challenges mean that simply porting existing desktop video conferencing solutions to portable devices does not provide the best user experience. Fortunately, these mobile devices also have many advantages that we can exploit to enable better-quality portable video conferences. In this paper we describe how we exploit the devices' mobility and embedded sensors to detect and fix two problems that are often ignored but that adversely affect user experience: bad view angles and too-tiny views of people and content, especially in multi-party conferences. Please note that what we describe is very much an experimental prototype and not a finished project.

/pdf/avoiding-nostril-cam-and-postage-stamp-people-in-mobile-5eygrn087g.pdf

Avoiding nostril-cam and postage-stamp people in mobile video conferences

Examples disclosed herein provide the ability for a computing device to configure one microphone at a time from physically colocated devices to remain active for participating in a teleconference. In one example method, the computing device determines whether a first device with a first microphone on the teleconference is physically colocated with respect to a second device with a second microphone on the teleconference. When the first and second devices are physically colocated with respect to each other, the computing device configures either the first or second microphone to remain active for participating in the teleconference while the other of the first or second microphone is to be muted.

Muting microphones of physically colocated devices

Desktop video conferencing participants are often poorly positioned in their outgoing video — unaware of their appearance on camera. We combine face detection, feature tracking and motion detection for automatic real-time detection of poorly framed participants and subsequently provide framing feedback by compositing their incoming and outgoing video streams. Our solution provides participants visual feedback only while they have framing problems. Otherwise the display shows only the remote participants, allowing users to focus fully on the conference. We analyze the system components and describe a user study that found advantages of our approach over the existing mirror window solution.

Visual framing feedback for desktop video conferencing

This document describes the technology behind the accompanying video, which gives a demonstration of determining the dynamic group membership of a meeting by matching patterns of relative audio silence, or "silence signatures," sensed by mobile devices.

Mary Baker

Papers

Interaction Platforms, Energy Conservation, Behavior Change Research, and More

Avoiding nostril-cam and postage-stamp people in mobile video conferences

Muting microphones of physically colocated devices

Visual framing feedback for desktop video conferencing

Sensing device co-location through patterns of silence