Bill van Melle, Ph.D.

Senior Research Scientist

Bill van Melle

Bill’s research focuses on technologies to support collaboration.  He has worked on the DICE project (in the Usable Smart Environments area), and more recently on myUnity, a system to promote presence awareness in the workplace. He earned his B.S. in Math and Computer Science from the University of Illinois and his Ph.D. in Computer Science from Stanford.

Co-Authors

Publications

2013

Private Aggregation for Presence Streams

Publication Details
  • Future Generation Computer Systems
  • May 28, 2013

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Collaboration technologies must support information sharing between collaborators, but must also take care not to share too much information or share information too widely. Systems that share information without requiring an explicit action by a user to initiate the sharing must be particularly cautious in this respect. Presence systems are an emerging class of applications that support collaboration. Through the use of pervasive sensors, these systems estimate user location, activities, and available communication channels. Because such presence data are sensitive, to achieve wide-spread adoption, sharing models must reflect the privacy and sharing preferences of their users. This paper looks at the role that privacy-preserving aggregation can play in addressing certain user sharing and privacy concerns with respect to presence data. We define conditions to achieve CollaPSE (Collaboration Presence Sharing Encryption) security, in which (i) an individual has full access to her own data, (ii) a third party performs computation on the data without learning anything about the data values, and (iii) people with special privileges called “analysts” can learn statistical information about groups of individuals, but nothing about the individual values contributing to the statistic other than what can be deduced from the statistic. More specifically, analysts can decrypt aggregates without being able to decrypt the individual values contributing to the aggregate. Based in part on studies we carried out that illustrate the need for the conditions encapsulated by CollaPSE security, we designed and implemented a family of CollaPSE protocols. We analyze their security, discuss efficiency tradeoffs, describe extensions, and review more recent privacy-preserving aggregation work.

2012
Publication Details
  • CHI 2012
  • May 7, 2012

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Affect influences workplace collaboration and thereby impacts a workplace's productivity. Participants in face-toface interactions have many cues to each other's affect, but work is increasingly carried out via computer-mediated channels that lack many of these cues. Current presence systems enable users to estimate the availability of other users, but not their affect states or communication preferences. This work investigates relationships between affect state and communication preferences and demonstrates the feasibility of estimating affect state and communication preferences from a presence state stream.
Publication Details
  • Fuji Xerox Technical Report No.21 2012
  • Feb 2, 2012

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Modern office work practices increasingly breach traditional boundaries of time and place, making it difficult to interact with colleagues. To address these problems, we developed myUnity, a software and sensor platform that enables rich workplace awareness and coordination. myUnity is an integrated platform that collects information from a set of independent sensors and external data aggregators to report user location, availability, tasks, and communication channels. myUnity's sensing architecture is component-based, allowing channels of awareness information to be added, updated, or removed at any time. Multiple channels of input are combined and composited into a single, high-level presence state. Early studies of a myUnity deployment have demonstrated that the platform allows quick access to core awareness information and show that it has become a useful tool for supporting communication and collaboration in the modern workplace.
2011
Publication Details
  • ACM Multimedia Industrial Exhibits
  • Nov 28, 2011

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Modern office work practices increasingly breach traditional boundaries of time and place, making it difficult to interact with colleagues. To address these problems, we developed myUnity, a software and sensor platform that enables rich workplace awareness and coordination. myUnity is an integrated platform that collects information from a set of independent sensors and external data aggregators to report user location, availability, tasks, and communication channels. myUnity's sensing architecture is component-based, allowing channels of awareness information to be added, updated, or removed at any time. Our current system includes a variety of sensor and data input, including camera-based activity classification, wireless location trilateration, and network activity monitoring. These and other input channels are combined and composited into a single, high-level presence state. Early studies of a myUnity deployment have demonstrated that use of the platform allows quick access to core awareness information and show it has become a useful tool supporting communication and collaboration in the modern workplace.
Publication Details
  • MobileHCI
  • Aug 30, 2011

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Modern office work practices increasingly breach traditional boundaries of time and place, increasing breakdowns workers encounter when coordinating interaction with colleagues. We conducted interviews with 12 workers and identified key problems introduced by these practices. To address these problems we developed myUnity, a fully functional platform enabling rich workplace awareness and coordination. myUnity is one of the first integrated platforms to span mobile and desktop environments, both in terms of access and sensing. It uses multiple sources to report user location, availability, tasks, and communication channels. A pilot field study of myUnity demonstrated the significant value of pervasive access to workplace awareness and communication facilities, as well as positive behavioral change in day-to-day communication practices for most users. We present resulting insights about the utility of awareness technology in flexible work environments.

Secured histories for presence systems

Publication Details
  • SECOTS 2011
  • May 23, 2011

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As sensors become ever more prevalent, more and more information will be collected about each of us. A longterm research question is how best to support beneficial uses while preserving individual privacy. Presence systems are an emerging class of applications that support collaboration. These systems leverage pervasive sensors to estimate end-user location, activities, and available communication channels. Because such presence data are sensitive, to achieve wide-spread adoption, sharing models must reflect the privacy and sharing preferences of the users. To reflect users' collaborative relationships and sharing desires, we introduce CollaPSE security in which an individual has full access to her own data, a third party processes the data without learning anything about the data values, and users higher up in the hierarchy learn only statistical information about the employees under them. We describe simple schemes that efficiently realize CollaPSE security for time series data. We implemented these protocols using readily available cryptographic functions, and integrated the protocols with FXPAL's MyUnity presence system.
2010
Publication Details
  • NPUC2010
  • Oct 22, 2010

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The massive amounts of information that are being collected about each of us will only increase as sensors become ever cheaper and more powerful. Analysis of this wealth of data supports advances in medicine and public health, improved software and services through user pattern analysis, and more efficient economic mechanisms. At the same time, the potential for misuse of such data is significant. A long-term research question is how best to support beneficial uses while inhibiting misuse. One approach is to enable individuals to maintain tighter control of their own data while still supporting the computation of group statistics. Currently, analysts are usually given access to all data in order to compute statistics, and often use a third party service provider to store, or even process, such data. Either the third party has access to all data or the data are encrypted, in which case the third party does no processing. An interesting research question is how to provide mechanisms to support "need to know" security in which an individual has full access to her own data, the third party learns nothing about the data but can nevertheless contribute to the processing, and the analyst learns only the desired statistics. We have explored "need to know" security in connection with MyUnity, a prototype awareness system. MyUnity collects data from a variety of sources and displays summary presence states, such as ``in office'' or ``with visitor,'' computed from the received data. MyUnity was deployed in a small research lab and has been in use by over 30 people for more than a year. To avoid concerns about misuse, the system did not store any data initially. The researchers developing the system were interested, however, in analyzing usage patterns, and users expressed interest in seeing personal trends, activity patterns of coworkers, and long-term data pooled across groups of users, all requiring data to be stored. At the same time, users continued to be concerned about misuse of stored data. We looked at ``need to know'' security for cases in which, at each time step, each member of a group of users has a value (i.e., a presence state) to contribute, and the group would like to provide only an aggregate view of those values to people outside their group. We designed and implemented an efficient protocol that enables each user to encrypt under her own key in such a way that a third party can compute an encryption of a sum across values encrypted under different keys without the need for further interactions with the individuals. The protocol provides means for an analyst to decrypt the encrypted sum. We designed key structures and extensions to provide a family of efficient non-interactive ``need to know'' protocols for time series data in which the analyst learns only the statistics, not the individual data values, and the third party learns nothing about the values.
2009
Publication Details
  • Book chapter in "Designing User Friendly Augmented Work Environments" Series: Computer Supported Cooperative Work Lahlou, Saadi (Ed.) 2009, Approx. 340 p. 117 illus., Hardcove
  • Sep 30, 2009

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The Usable Smart Environment project (USE) aims at designing easy-to-use, highly functional next-generation conference rooms. Our first design prototype focuses on creating a "no wizards" room for an American executive; that is, a room the executive could walk into and use by himself, without help from a technologist. A key idea in the USE framework is that customization is one of the best ways to create a smooth user experience. Since the system needs to fit both with the personal leadership style of the executive and the corporation's meeting culture, we began the design process by exploring the work flow in and around meetings attended by the executive. Based on our work flow analysis and the scenarios we developed from it, USE developed a flexible, extensible architecture specifically designed to enhance ease of use in smart environment technologies. The architecture allows customization and personalization of smart environments for particular people and groups, types of work, and specific physical spaces. The first USE room was designed for FXPAL's executive "Ian" and installed in Niji, a small executive conference room at FXPAL. The room Niji currently contains two large interactive whiteboards for projection of presentation material, for annotations using a digital whiteboard, or for teleconferencing; a Tandberg teleconferencing system; an RFID authentication plus biometric identification system; printing via network; a PDA-based simple controller, and a tabletop touch-screen console. The console is used for the USE room control interface, which controls and switches between all of the equipment mentioned above.
Publication Details
  • In Proceedings of CHI 2009
  • Apr 4, 2009

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One of the core challenges now facing smart rooms is supporting realistic, everyday activities. While much research has been done to push forward the frontiers of novel interaction techniques, we argue that technology geared toward widespread adoption requires a design approach that emphasizes straightforward configuration and control, as well as flexibility. We examined the work practices of users of a large, multi-purpose conference room, and designed DICE, a system to help them use the room's capabilities. We describe the design process, and report findings about the system's usability and about people's use of a multi-purpose conference room.
2006
Publication Details
  • UbiComp 2006 Workshop position paper
  • Sep 20, 2006

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We describe our work-in-progress: a "wizard-free" conference room designed for ease of use, yet retaining next-generation functionality. Called USE (Usable Smart Environments), our system uses multi-display systems, immersive conferencing, and secure authentication. It is based in cross-cultural ethnographic studies on the way people use conference rooms. The USE project has developed a flexible, extensible architecture specifically designed to enhance ease of use in smart environment technologies. The architecture allows customization and personalization of smart environments for particular people and groups, types of work, and specific physical spaces. The system consists of a database of devices with attributes, rooms and meetings that implements a prototype-instance inheritance mechanism through which contextual information (e.g. IP addresses application settings, phone numbers for teleconferencing systems, etc.) can be associated