David J. Malan

Bio: David J. Malan is an academic researcher from Harvard University. The author has contributed to research in topics: Computer science & Wireless sensor network. The author has an hindex of 14, co-authored 39 publications receiving 3612 citations.

Sensor networks for emergency response: challenges and opportunities

Abstract: Sensor networks, a new class of devices has the potential to revolutionize the capture, processing, and communication of critical data for use by first responders. CodeBlue integrates sensor nodes and other wireless devices into a disaster response setting and provides facilities for ad hoc network formation, resource naming and discovery, security, and in-network aggregation of sensor-produced data. We designed CodeBlue for rapidly changing, critical care environments. To test it, we developed two wireless vital sign monitors and a PDA-based triage application for first responders. Additionally, we developed MoteTrack, a robust radio frequency (RF)-based localization system, which lets rescuers determine their location within a building and track patients. Although much of our work on CodeBlue is preliminary, our initial experience with medical care sensor networks raised many exciting opportunities and challenges.

CodeBlue: An Ad Hoc Sensor Network Infrastructure for Emergency Medical Care

Abstract: Sensor devices integrating embedded processors, low-power, lowbandwidth radios, and a modest amount of storage have the potential to enhance emergency medical care. Wearable vital sign sensors can track patient status and location, while simultaneously operating as active tags. We introduce CodeBlue, a wireless infrastructure intended for deployment in emergency medical care, integrating low-power, wireless vital sign sensors, PDAs, and PC-class systems. CodeBlue will enhance first responders’ ability to assess patients on scene, ensure seamless transfer of data among caregivers, and facilitate efficient allocation of hospital resources. Intended to scale to very dense networks with thousands of devices and extremely volatile network conditions, this infrastructure will support reliable, ad hoc data delivery, a flexible naming and discovery scheme, and a decentralized security model. This paper introduces our architecture and highlights research challenges being addressed by the CodeBlue

A public-key infrastructure for key distribution in TinyOS based on elliptic curve cryptography

Abstract: We present the first known implementation of elliptic curve cryptography over F/sub 2p/ for sensor networks based on the 8-bit, 7.3828-MHz MICA2 mote. Through instrumentation of UC Berkeley's TinySec module, we argue that, although secret-key cryptography has been tractable in this domain for some time, there has remained a need for an efficient, secure mechanism for distribution of secret keys among nodes. Although public-key infrastructure has been thought impractical, we argue, through analysis of our own implementation for TinyOS of multiplication of points on elliptic curves, that public-key infrastructure is, in fact, viable for TinySec keys' distribution, even on the MICA2. We demonstrate that public keys can be generated within 34 seconds, and that shared secrets can be distributed among nodes in a sensor network within the same, using just over 1 kilobyte of SRAM and 34 kilobytes of ROM.

Scratch for budding computer scientists

Abstract: Scratch is a "media-rich programming environment" recently developed by MIT's Media Lab that "lets you create your own animations, games, and interactive art." Although Scratch is intended to "enhance the development of technological fluency [among youths] at after-school centers in economically disadvantaged communities," we find rarkable potential in this programming environment for higher education as well.We propose Scratch as a first language for first-time programmers in introductory courses, for majors and non-majors alike. Scratch allows students to program with a mouse: programmatic constructs are represented as puzzle pieces that only fit together if "syntactically" appropriate. We argue that this environment allows students not only to master programmatic constructs before syntax but also to focus on probls of logic before syntax. We view Scratch as a gateway to languages like Java.To validate our proposal, we recently deployed Scratch for the first time in higher education via harvard Summer School's Computer Science S-1: Great Ideas in Computer Science, the summertime version of a course at harvard College. Our goal was not to improve scores but instead to improve first-time programmers' experiences. We ultimately transitioned to Java, but we first introduced programming itself via Scratch. We present in this paper the results of our trial.We find that, not only did Scratch excite students at a critical time (i.e.,, their first foray into computer science), it also familiarized the inexperienced among th with fundamentals of programming without the distraction of syntax. Moreover, when asked via surveys at term's end to reflect on how their initial experience with Scratch affected their subsequent experience with Java, most students (76%) felt that Scratch was a positive influence, particularly those without prior background. Those students (16%) who felt that Scratch was not an influence, positive or negative, all had prior programming experience.

Implementing public-key infrastructure for sensor networks

Abstract: We present a critical evaluation of the first known implementation of elliptic curve cryptography over F2p for sensor networks based on the 8-bit, 7.3828-MHz MICA2 mote. We offer, along the way, a primer for those interested in the field of cryptography for sensor networks. We discuss, in particular, the decisions underlying our design and alternatives thereto. And we elaborate on the methodologies underlying our evaluation.Through instrumentation of UC Berkeley's TinySec module, we argue that, although symmetric cryptography has been tractable in this domain for some time, there has remained a need, unfulfilled until recently, for an efficient, secure mechanism for distribution of secret keys among nodes. Although public-key infrastructure has been thought impractical, we show, through analysis of our original implementation for TinyOS of point multiplication on elliptic curves, that public-key infrastructure is indeed viable for TinySec keys' distribution, even on the MICA2. We demonstrate that public keys can be generated within 34 seconds and that shared secrets can be distributed among nodes in a sensor network within the same time, using just over 1 kilobyte of SRAM and 34 kilobytes of ROM. We demonstrate that communication costs are minimal, with only 2 packets required for transmission of a public key among nodes. We make available all of our source code for other researchers to download and use. And we discuss recent results based on our work that corroborate and improve upon our conclusions.

Scratch: programming for all

Abstract: "Digital fluency" should mean designing, creating, and remixing, not just browsing, chatting, and interacting.

Context Aware Computing for The Internet of Things: A Survey

Abstract: As we are moving towards the Internet of Things (IoT), the number of sensors deployed around the world is growing at a rapid pace. Market research has shown a significant growth of sensor deployments over the past decade and has predicted a significant increment of the growth rate in the future. These sensors continuously generate enormous amounts of data. However, in order to add value to raw sensor data we need to understand it. Collection, modelling, reasoning, and distribution of context in relation to sensor data plays critical role in this challenge. Context-aware computing has proven to be successful in understanding sensor data. In this paper, we survey context awareness from an IoT perspective. We present the necessary background by introducing the IoT paradigm and context-aware fundamentals at the beginning. Then we provide an in-depth analysis of context life cycle. We evaluate a subset of projects (50) which represent the majority of research and commercial solutions proposed in the field of context-aware computing conducted over the last decade (2001-2011) based on our own taxonomy. Finally, based on our evaluation, we highlight the lessons to be learnt from the past and some possible directions for future research. The survey addresses a broad range of techniques, methods, models, functionalities, systems, applications, and middleware solutions related to context awareness and IoT. Our goal is not only to analyse, compare and consolidate past research work but also to appreciate their findings and discuss their applicability towards the IoT.

TinySec: a link layer security architecture for wireless sensor networks

Abstract: We introduce TinySec, the first fully-implemented link layer security architecture for wireless sensor networks. In our design, we leverage recent lessons learned from design vulnerabilities in security protocols for other wireless networks such as 802.11b and GSM. Conventional security protocols tend to be conservative in their security guarantees, typically adding 16--32 bytes of overhead. With small memories, weak processors, limited energy, and 30 byte packets, sensor networks cannot afford this luxury. TinySec addresses these extreme resource constraints with careful design; we explore the tradeoffs among different cryptographic primitives and use the inherent sensor network limitations to our advantage when choosing parameters to find a sweet spot for security, packet overhead, and resource requirements. TinySec is portable to a variety of hardware and radio platforms. Our experimental results on a 36 node distributed sensor network application clearly demonstrate that software based link layer protocols are feasible and efficient, adding less than 10% energy, latency, and bandwidth overhead.