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MobiCom 2000 Tutorials
 
 
 
       
August 6

(Sunday)

 

AM T1:Mobile IP in the Current and Future Internet T2:Database Management Systems and Mobile Computing T3: Personal Area Networking Over Bluetooth
PM T4: Service Discovery and Device Cooperation
August 7

 (Monday)

AM T5: Energy Efficiency in Mobile Computing and Networking T7:Mobile Ad hoc Networks: Routing, MAC and Transport Issues T8: Shaping the User Experience for Handheld Computing
PM T6: Mobile Voice over IP

 
Tutorial 1 : Mobile IP in the Current and Future Internet      
        (Sunday August 6,  Full day)

Speaker:

David B. Johnson
Rice University and Carnegie Mellon University 
dbj@cs.cmu.edu
http://www.monarch.cs.cmu.edu/

Abstract:

The global Internet continues to grow at a tremendous rate, now with over 72 million hosts.  At the same time, portable computing devices such as laptops and palmtops have become widely available at very affordable prices, and many new wireless networking products and services are becoming available based on technologies such as spread spectrum radio, infrared, cellular, and satellite.  With these dramatic increases in portability and ease of network access, it becomes natural for users to expect to be able to access the Internet at any time and from anywhere, and to transparently remain connected and continue to use the network as they move about.  However, without specific support for mobility in IP, packets destined to a mobile node would not be able to reach it while the mobile node is away from its home network, due to the nature of IP (or any internetwork) routing.

Mobile IP is a technology that has been developed to solve this problem. The area of Mobile IP has seen rapidly increasing interest among researchers and has already become the basis of some commercial mobile network systems, with more expected to follow in coming years. Indeed, with the development of IPv6 to replace the current version of IP in use in the Internet today (IPv4), Mobile IP is expected to become a standard feature of all IP implementations.  This tutorial will cover the design and operation of Mobile IP, as well as the rationale behind the design choices.  We will focus on the important concepts and principles behind the protocol, its development, and its future.

Outline:

1. Introduction - Why Mobile Networking and Mobile IP?
2. Basic Operation of Mobile IP for IPv4
3. Mobile IP Security Problems and Solutions
4. Route Optimization for Mobile IPv4
5. IPv6 and Mobile IP for IPv6
6. Future Directions and Open Areas

Intended Audience:

The tutorial is intended for networking and computer science researchers, wireless product engineers, cellular telephony engineers, and anyone interested in mobile networking.  It is also intended for end users working with or considering deploying Mobile IP systems or related protocols.  Participants should come away with an understanding of the underlying concepts of Mobile IP, the design and use of the protocol, and the current state and future directions for the area.

Speaker's Biography:

David B. Johnson has recently joined Rice University as an Associate Professor of Computer Science and Electrical and Computer Engineering. Prior to this he was on the faculty at Carnegie Mellon University for eight years, where he was an Associate Professor in the School of Computer Science. His research interests are in the areas of network protocols, distributed systems, and operating systems.  He received a B.A. in computer science and mathematical sciences in 1982, an M.S. in computer science in 1985, and a Ph.D. in computer science in 1990, all from Rice University.  He was one of the main designers of the IETF Mobile IPv4 protocol and is the primary designer of Mobile IPv6.  He has served as a member of the Technical Program Committee for over 20 international conferences and workshops, is a member of the editorial board for IEEE/ACM Transactions on Networking, and is an area editor for the ACM/Baltzer journal Mobile Networks and Applications and the ACM SIGMOBILE magazine Mobile Computing and Communications Review.  He is also an Executive Committee member and the Treasurer for ACM SIGMOBILE.

 

Tutorial 2: Database Management Systems and Mobile Computing
(Sunday August 6, Full day)
 
Speakers:

Wang-Chien Lee
GTE Laboratories Inc.
Waltham, MA 02451
wlee@gte.com

Sandeep K. S. Gupta
Colorado State University
Ft. Collins, CO 80523
gupta@cs.colostate.edu

Pradip K. Srimani
Colorado State University
Ft. Collins, CO 8052

srimani@cs.colostate.edu

Abstract:

Mobile computing is the merger of advances in portable computing and wireless communication with the aim of providing seamless and ubiquitous services for mobile users. In mobile environments, database applications are enhanced with the useful features of wireless technology. However, mobile computing environments have severe resource constraints and unstable operating conditions. Many software problems associated with data management, transaction management, and data recovery have their origin in distributed database systems. In mobile computing, however, these problems become more difficult to solve, mainly because of the narrow bandwidth of the wireless communication channels, the relatively short active life of the power supply in mobile devices, and the changing locations of required information (sometimes in cache, sometimes in air and sometimes at the server) and mobile users.  Further, in many mobile database applications, data changes very rapidly (or even constantly). Users need to receive timely information in order to make critical decisions (e.g., stock market information and trading). This tutorial will provide an overview of the academic research and industry activities on mobile database and wireless data services. The focus will be on systems aspects of mobile computing and the new data management architecture and mechanisms being adapted for mobile environment.

Outline:

1. Introduction
    - Why mobile database systems? 
    - Potential applications, technical issues and technologies
2. Location Services and Management, Location Based Queries.
3. Wireless Data Dissemination
    - Broadcast channels, indexing techniques
4. Data Distribution and Synchronization
5. Transactions, Recovery and Mobility
6. Mobile Database Design
    - Intermittently synchronized databases (ISDBs)
7. Industry Activities
    - Standards and alliances, 
    - Products, platforms, and services

Intended Audience:

Engineers, scientists, software developers, system analysts, network users and designers, project managers, faculty members, graduate and undergraduate students, who are interested in knowing the fundamentals of designing mobile databases and the recent advances and practices in the field. Participants will get an overview of how user mobility provides an interesting new dimension to distributed database design.

Speakers' Biographies:

Wang-Chien Lee is a principal member of technical staff in the Advanced Systems Laboratory of GTE Laboratories in Waltham, Massachusetts.  He received the PhD degree in Computer and Information Science from the Ohio State University in 1996. His primary research activities lie in the areas of mobile databases, Web/XML data management, pervasive computing, object-oriented database systems, and telecommunications management network (TMN).  Dr. Lee has given a tutorial and several talks on various topics related to mobile data dissemination and management. He was the program co-chair for the First International Conference on Mobile Data Access (MDA'99), the International Workshop on Wireless Network and Mobile Computing (WNMC'99), and the International Workshop on Pervasive Computing (PC2000). 

Sandeep Kumar S. Gupta received the M.S. and Ph.D. degree in computer and information science from The Ohio State University, Columbus, Ohio, in 1991 and 1995, respectively. He is currently an Assistant professor in Department of Computer Science at Colorado State University, Ft.  Collins, Colorado.  Prior to joining Colorado State University he has held research and teaching positions at Duke University and Ohio University. Dr. Gupta has given tutorials on Mobile IP and Mobile ATM. He was program chair for International workshop on Group Communication and program co-chair for International Workshop on Wireless Networks and Mobile Computing, and International Workshop on Pervasive Computing. He was a program committee member for Mobile Data Access (MDA'99) and 1999 International Conference on Parallel Processing (ICPP'99).

Pradip K. Srimani is Professor of Computer Science at Colorado State University, Ft. Collins, Colorado. He has previously served the faculty of India Statistical Institute, Calcutta, Gesselschaft fuer Mathematik und Datenverarbeitung, Bonn, West Germany, Indian Institute of Management, Calcutta, India and Southern Illinois University, Carbondale, Illinois. He is a Fellow of IEEE and a member of ACM; he is currently the Editor-in-Chief of IEEE Computer Society Press and is a member of the Editorial Boards of IEEE Software Magazine and IEEE Transactions on Knowledge and Data Engineering.  He has guest-edited special issues for IEEE Software, VLSI Design, Journal of Systems & Software, and Journal of Computer & Software Engineering, IEEE Transactions on Software Engineering, IEEE Computer, International Journal of System Software, Parallel Computing.
 

Tutorial 3: Personal Area Networking Over Bluetooth
(Sunday August 6, Morning)

Speaker:

Pravin Bhagwat
AT&T Labs Research
Florham Park, NJ 07932
pravin@acm.org

Abstract:

Bluetooth is a promising new technology that is aimed at supporting wireless connectivity among cell phones, headsets, PDAs, digital cameras, and laptop computers. Initially, the technology will be used as replacement for point-to-point cables, but solutions for forming personal area networks of Bluetooth devices will evolve in the near future. This tutorial is aimed at computer professionals, academics, network architects, and application developers who wish to develop deeper understanding of this new technology. The tutorial will also illustrate in what ways low cost, low power, and form factor features of Bluetooth are different from other short range wireless technologies, such as 802.11 and HomeRF. 

The tutorial will first provide the necessary background in radio communication, signal processing, and low power circuit design and then explain the design choices made in Bluetooth 1.0 specifications. A detailed discussion of radio, baseband, link manager, L2CAP, RFCOMM, and SDP layers will be presented next. 

In principle, using Bluetooth radio modules it is possible to form an ad hoc network of devices, but the techniques for forming such networks have not been fully explored yet. The last quarter of the tutorial will be devoted to the review of the initial results in this area (namely, the techniques for characterizing Bluetooth scatternets, algorithms for self-organization, and methods for routing packets over Bluetooth scatternets). The tutorial will conclude with a discussion of open problems.

Outline:

1. Review of basic concepts (RF, signal processing) and technology trends (low cost, low power, small form factor) 
2. Overview of Bluetooth 1.0 specifications 
3. Multi-hop networking over Bluetooth scatternets 
4. TCP/IP over Bluetooth 
5. Future directions and open problems 

Intended Audience:

The tutorial is intended for researchers and practitioners who want to learn more about Bluetooth 1.0 standard. Computer professionals who want to develop better understanding of technology trends and identify new market opportunities in the space of short range wireless networking will also benefit from this tutorial. Basic understanding of layered network architecture is expected. No background in analog radio, signal processing, or wireless communication is required. Researchers who want to identify open research problems in the area of personal area networking will also find this tutorial very useful.

Speaker's Biography:

Pravin Bhagwat is a member of technical staff at AT&T Labs. Prior to joining AT&T he was a member of research staff at IBM Thomas J. Watson Research Center, where he worked on a number of topics including mobile computing, networking protocols, proxies, and firewalls. He is the chief architect of BlueSky, an indoor wireless networking system for palmtop computers, and the co-inventor of TCP splicing, a technique for building fast application layer proxies. He actively serves on program committees of mobile computing and networking conferences and has published several technical papers in the area of mobile computing and networking. He has a Ph.D. in computer science from theUniversity of Maryland, College Park. He is also an active member of the Bluetooth PAN working group.
 

Tutorial 4: Service Discovery and Device Cooperation
(Sunday August 6, Afternoon)

Speaker:

Golden Richard III
University of New Orleans
golden@cs.uno.edu

Abstract:

The broad goals of service advertisement and discovery are to enhance device cooperation and interoperability and to reduce configuration hassles. These technologies are useful in wired settings, because they allow devices to be dynamically installed, discovered, and removed. But service discovery is perhaps even more exciting in mobile settings, where it can be used to augment the abilities of resource-poor devices. Suitable form factors for mobile devices clearly mandate trading peripherals for size and weight reductions. Who wants to carry around a 3-pound PDA, even if it can print? Using service discovery technologies, mobile units will be able to configure themselves dynamically to rely on neighboring devices for storage of large data sets, fax, high-speed network access, and printing. Service discovery can also enable sophisticated data synchronization schemes.

In this tutorial, we will survey a number of service advertisement and discovery technologies, including Bluetooth SDP, Salutation, Jini, SLP, and Microsoft's Universal Plug and Play. Some of these technologies are complimentary and most offer similar functionality. But the philosophies are divergent and the players are not entirely friendly. 

We'll look at the architectures in detail, examine the promise of these technologies, and explore open issues. A brief introduction to mobile computing issues will set the stage, so the tutorial will be interesting to a wide audience. You'll emerge with an understanding of the basic issues, and without having to read the 1500 page Bluetooth specification! 

Outline:

1. Brief introduction to mobile computing
2. Issues in service discovery and device cooperation
3. Specific technologies in detail: Bluetooth SLP, Jini, Salutation, Microsoft's UPnP
4. Comparison of technologies
5. Security issues 
6. Conclusions and areas for further study

Intended Audience:

This tutorial will appeal to anyone interested in a survey of the current technologies for service discovery and device cooperation (Jini, Bluetooth, Microsoft's offerings, etc.) including students, software developers, and researchers. No significant background in mobile computing is assumed, but a basic computer science background will be helpful. A detail bibliography will be provided in the tutorial materials for further study.

Speaker's Biography:

Golden G. Richard III is an Assistant Professor of Computer Science at the University of New Orleans in Louisiana. His broad research interests include mobile computing, wireless networking, operating systems, and fault tolerance. Dr. Richard is on the Executive Committee of the IEEE Technical Committee on the Internet (TCI) and is actively involved in the organization of several mobile computing and networking conferences. He is a member of the ACM, IEEE, and is USENIX's Educational Outreach Liaison for the University of New Orleans. Dr. Richard is an academic member of the Salutation Consortium. When he's not hacking, he can be found consuming New Orleans jazz or covered in dirt, in his garden.
 

Tutorial 5: Energy Efficiency in Mobile Computing and Networking
(Monday August 7, Morning)

Speaker:

Mani Srivastava
University of California, Los Angeles
mbs@ee.ucla.edu

Abstract:

Energy efficiency directly affects battery life and portability, and is perhaps the single most important design metric in mobile and wireless systems. It is becoming even more important with a variety of embedded devices, such as sensors, becoming  wirelessly networked. The mismatch between the slow improvement in batteries on the one hand, and increasing user expectations and shrinking form factors in wireless devices on the other hand, makes energy efficient wireless system design particularly challenging.

Wireless systems, where the energy consumption for "communication" is dictated by the link budget, require going beyond low-power implementation techniques developed for "computing" systems. Higher layers of the system also need to be power aware and energy efficient. A comprehensive discussion of battery technology, sources of power consumption in computing and communication, and generic low-power hardware and software implementation techniques will be followed in the tutorial by a presentation of techniques such as low-power network protocols that are specific to wireless and mobile systems. 

Commercial trends such as low-power "mobile" processors and power management APIs, and the latest research in the field will also be described. With a balanced presentation of basic concepts, new ideas, real-life applications, and research trends, the tutorial should interest practicing engineers as well as researchers.

Outline:

1. Introduction
    - overview of the field, commercial and technology trends
    - sources of power consumption
    - battery technology
2. Generic low-power design techniques
    - voltage scaling, dynamic voltage/frequency
    - software: estimation, scheduling, data structures
3. Power consumption in radios
    - sources of power consumption, link budget
    - techniques for lower-power and power-aware radios
4. Low-power network protocols
    - energy efficient link layer
    - low-power MAC protocols
    - power-aware routing
    - power-aware transport protocols
5. Application and OS level techniques
    - CPU and subsystem shutdown, predictive shutdown
    - scheduling with dynamic voltage/frequency CPUs
    - explicit management of power by applications
    - power-efficient encryption
6. Commercial and research trends
    - new "low-power" processors for mobile applications
    - APIs for OS level power management
    - ultra low-power wireless sensor networks
    - ambient power harvesting and scavenging

Intended Audience:

The tutorial is targeted at both practicing engineers and researchers who want to learn about energy efficiency and design for low power across the various layers (physical, protocol, application) of mobile and wireless computing and networking systems. To the practicing engineers the tutorial will provide a comprehensive treatment of recent developments in design for low power at various layers in the system, and case studies of real-life applications incorporating ideas described in the tutorial. To the researchers the tutorial will provide an opportunity to learn about low power related research issues in mobile computing, and particularly problems that arise from the strong interplay of physical, protocol, middleware, and application level considerations that is typical of wireless systems. The tutorial is self contained with an extended bibliography to guide the interested participants to later delve into more details, and would be accessible to participants with typical EE and CS backgrounds.

Speaker's Biography:

Mani Srivastava is an Associate Professor at UCLA. He received MS and Ph.D. degrees from Berkeley, and worked for several years in Networked Computing Research at Bell Labs. His research at UCLA is on networked and embedded systems, focusing particularly on low-power, sensor networking, wireless QoS mobility, and terminal architecture issues. He leads DARPA and NSF funded projects in these areas. He has several patents, and has published extensively. His recent awards include ACM Design Automation Conference 2000 Student Design Contest Honorable Mention Award, the Okawa Foundation Grant, and the NSF CAREER Award.
 

Tutorial 6: Mobile voice over IP
(Monday August 7, Afternoon)

Speakers:

Prathima Agrawal
Telcordia Technologies
pagrawal@research.telcordia.com

Parmesh Ramanathan
University of Wisconsin, Madison
parmesh@ece.wisc.edu

Cormac J. Sreenan
University College Cork, Ireland
cjs@cs.ucc.ie

Abstract:

Voice-over-IP (VoIP) is attracting significant interest in both the  telecommunications and Internet communities. The emergence of packet telephony will create new services and allow greater flexibility and efficiency in the way people communicate. At the same time, demand for cellular telephony is exploding, with the number of subscribers predicted to exceed 500 Million in the year 2000. The marriage of these two technologies promises the benefits of packet telephony combined with the freedom of user mobility. It does, however, raise a set of difficult technological challenges. The aim of this tutorial is to explain the key concepts and technologies involved in designing a mobile voice-over-IP system, and identify the opportunities and technical challenges that arise. 

Outline:

1. Introduction - motivation for VoIP, telephony and mobility background
2. Networking - transport requirements, QoS (medium access, 3G wireless, RSVP) Mobile-IP, location tracking and handoff performance
3. Protocols and services - signaling protocols (SIP, H.323), transport (RTP), user directories, the impact of mobility
4. Conclusion - summary of key technologies, discussion of open issues and recent research

Intended Audience:

The tutorial is targeted at practicing engineers and service providers in the telecommunications and data networking areas who are interested in learning about voice-over-IP and its role in the evolution of the mobile communications industry. The material will also appeal to researchers with interests in mobile computing, packet telephony or multimedia networking, who wish to learn more about the challenges that arise in the marriage of voice-over-IP and mobile computing technologies. The tutorial is self-contained, with a web page to guide interested participants to later delve into more detail. Prior exposure to the fundamentals of IP and wireless data networking will be a plus, though not essential.

Speakers' Biographies:

Prathima Agrawal is Executive Director of the Computer Networking Research Department and Assistant Vice President of the Internet Architecture Research Laboratory at Telcordia Technologies (formerly Bellcore), Morristown, NJ. She is also a Visiting Professor of Electrical and Computer Engineering, Wireless Networking Laboratory (WINLAB), Rutgers University, NJ. Prior to this she worked for 20 years in AT&T/Lucent Bell Laboratories in Murray Hill, NJ, where she was Head of the Networked Computing Research Department. Presently, she leads the ITSUMO joint research project between Telcordia and Toshiba Corp.. ITSUMO is a third generation wireless access system for multimedia communication over end-to-end packet networks. Dr. Agrawal received her Ph.D. degree in Electrical Engineering from the University of Southern California. Her research interests are computer networks, mobile and wireless computing and communication systems and parallel processing. 

Parmesh Ramanathan is an Associate Professor in the Department of Electrical and Computer Engineering  and in the Department of Computer Science at University of Wisconsin, Madison, USA. He has been faculty member at the University of Wisconsin since 1989. Presently, he is also a consultant to the ITSUMO project at Telcordia Technologies, Inc.  where has been looking at quality of service issues in the third generation wireless IP networks. He holds a Ph.D. in Computer Science and Engineering from University of  Michigan, Ann Arbor. His research interests are in the areas of wireless and wireline networking, real-time systems, fault-tolerant computing, and distributed systems. 

Cormac J. Sreenan is a Professor of Computer Science at University College Cork in Ireland. Prior to taking up his current position in August 1999, he was a Principal  Technical Staff Member at AT&T Labs Research in Florham Park, NJ, USA, and a Member of Technical Staff at Bell Labs in Murray Hill, NJ, USA. While at AT&T he was a principal investigator on the TOPS and WISP projects, that proposed new directory architectures and mobility protocols for packet telephone systems. He holds a Ph.D. in Computer Science from Cambridge University. His research interests include multimedia networking, mobile computing, and packet telephony.
 

Tutorial 7: Mobile Ad hoc Networks: Routing, MAC and Transport Issues
(Monday August 7, Full day)


Speaker:

Nitin Vaidya
Texas A&M University
College Station, TX 77843-3112
vaidya@cs.tamu.edu

Abstract:

A mobile ad hoc network is a collection of mobile wireless nodes that can dynamically form a network without using any pre-existing network infrastructure. In general, routes between nodes in an ad hoc network may include multiple hops. Due to the potential ease of deployment, many practical applications have been conceived for ad hoc networks, including personal area networking, home networking, search-and-rescue operations, and battlefield applications.

When designing mobile ad hoc networks, several interesting and difficult problems arise due to shared nature of the wireless medium, limited transmission range of wireless devices, node mobility, and battery limitations. This tutorial will present an overview of issues related to medium access control (MAC), routing, and transport in mobile ad hoc networks, including interaction between the different layers of the protocol stack. Techniques proposed to improve performance of MAC, routing and transport protocols will be discussed. The tutorial will include a discussion of approaches for reducing energy consumption by nodes in a mobile ad hoc network. Some security-related issues will also be considered. In addition, the tutorial will discuss implementation-related problems, and mechanisms for integrating a mobile ad hoc network with existing wired networks. Finally, the tutorial will also present an overview of some standards activities related to ad hoc networking.

Outline:

1. Introduction to mobile ad hoc networks
2. Medium Access Control Protocols for ad hoc networks
3. Unicast Routing Protocols for mobile ad hoc networks
4. Performance of TCP and UDP in mobile ad hoc networks
5. Multicast and geocast protocols for mobile ad hoc networks
6. Techniques to reduce energy consumption 
7. Security-related issues
8. Implementation-related problems
9. Related standards activities
10. Conclusions and open problems

Intended Audience:

This tutorial is designed to provide an overview of the issues related to design and implementation of mobile ad hoc networks. The tutorial should benefit researchers as well as practitioners from industry and academia, who are interested in areas related to wireless communications, and mobile networking.

Speaker's Biography:

Nitin Vaidya is an Associate Professor of Computer Science at the Texas A&M University. He received Ph.D. from the University of Massachusetts at Amherst. He has held visiting positions at Microsoft Research and Sun Microsystems. His current research is in the areas of wireless networking and mobile computing. He presently serves as Program Co-Chair for the Workshop on Mobile Ad Hoc Networking and Computing (MobiHoc), and has served on program committees of several other conferences. He is a speaker for the Distinguished Visitors Program of the IEEE Computer Society and a recipient of a teaching award at the Texas A&M University. He is a Senior Member of the IEEE and a member of the ACM. For more information, see http://www.cs.tamu.edu/faculty/vaidya/.
 

Tutorial 8: Shaping the User Experience for Handheld Computing
(Monday August 7, Morning)

Speaker:

Phillip B. Shoemaker
Palm Inc.
pshoemak@palm.com

Abstract:

With the handheld computer becoming more horizontally successful, there is a need for designers to become aware of the tips and techniques necessary to design effective handheld applications. Many designers are unfamiliar with the unique requirements of handheld computers, and therefore attempt to use desktop metaphors on their designs. This tutorial will introduce design concepts used by the creators of the most popular and easy-to-use handheld computers. It includes designing screens and dialog boxes, designing for speed, using progressive disclosure, and employing benchmarks. It will also demonstrate the difference between designing a standalone device, and one that is connected. Additionally, it will talk about creating a complete solution for the user, that includes documentation concerns, packaging concerns, as well as affordability. Anyone who participates in product design activities for handheld applications could benefit from this class, including user interface designers, developers, managers, marketeers, usability professionals, technical writers and more. It is appropriate for beginners as well as seasoned professionals.

Outline:

1. Overview
2. Your first steps
3. Application design guidelines
4. Choosing the right platform
5. Differences between handheld and desktop computers
6. Getting to know your platform
7. Design guidelines
8. Packaging concerns - One stop shop
9. Documentation issues
10. Affordability
11. Designing a complete wireless solution

Intended Audience:

Anyone who participates in product design activities for handheld applications could benefit from this class, including user interface designers, developers, managers, marketers, usability professionals, technical writers and more. It is appropriate for beginners as well as seasoned professionals.

Speaker's Biography:

Phillip B. Shoemaker is Director of Development Tools at Palm Computing, where he is responsible for all development tools released for the Palm Computing Platform. Prior to Palm, he was Director of Software Development at PenRight!, where he was responsible for all software development and software design of handheld software. Phillip has over 13 years experience designing user interfaces for Sun Microsystems, Tandem Computers, Borland International, and Symantec Corporation, where he designed user interfaces for Delphi, JustWrite, and Q&A. Phillip is a committee member of BayCHI and the Human Factors Society, and has participated in CHI conferences since 1988. He was a co-presenter of a tutorial at the 1994 CHI Conference in Boston.