Publications Articles

2005
Forlines C, Shen C, Buxton B. “Glimpse: A Novel Input Model for Multi-Level Devices”. ACM CHI '05 Extended Abstracts on Human Factors in Computing Systems. 2005.Abstract
We describe a technique that supports the previewing of navigation, exploration, and editing operations by providing convenient Undo for unsuccessful and/or undesirable actions on multilevel input devices such as touch screens and pen-based computers. By adding a Glimpse state to traditional three-state pressure sensitive input devices, users are able to preview the effects of their editing without committing to them. From this Glimpse state, users can undo their action as easily as they can commit to it, making Glimpse most appropriate for systems in which the user is likely to try out many variations of an edit before finding the right one. Exploration is encouraged as the cumbersome returning to a menu or keyboard to issue an Undo command is eliminated. Glimpse has the added benefits that the negative effects of inconsistencies in the Undo feature within an application are reduced.
glimpse_a_novel_input_model.pdf
Shen C, Hancock MS, Forlines C, Vernier FD. “CoR2Ds: Context-Rooted Rotatable Draggables for Tabletop Interaction”. ACM CHI '05 Extended Abstracts on Human Factors in Computing Systems. 2005.Abstract
We present a new popup widget, called CoR2Ds (Context-Rooted Rotatable Draggables), designed for multi-user direct-touch tabletop environments. CoR2Ds are interactive callout popup objects that are visually connected (rooted) at the originating displayed object by a semi-transparent colored swath. CoR2Ds can be used to bring out meanus, display drilled-down or off-screen ancillary data such as metadata and attributes, as well as instantiate tools. CoR2Ds can be freely moved, rotated, and re-oriented on a tabletop display surface by fingers, hands, pointing devices (mice) or marking devices (such as a stylus or light pen). CoR2Ds address five issues for interaction techniques on interactive tabletop display surfaces: occlusion, reach, context on a cluttered display, readability, and concurrent/coordianted multi-user interaction. In this paper, we present the design, interaction and implementation of CoR2Ds. We also discuss a set of current usage scenarios.
cor2ds_context-rooted_rotatable_draggables_for_tabletop_interaction.pdf
Hancock MS, Shen C, Forlines C, Ryall K. “Exploring Non-Speech Auditory Feedback at an Interactive Multi-User Tabletop”. Proceedings of the 2005 Conference on Graphics Interface. 2005 :41-50.Abstract
We present two experiments on the use of non-speech audio at an interactive multi-touch, multiuser tabletop display. We first investigate the use of two categories of reactive auditory feedback: affirmative sounds that confirm user actions and negative sounds that indicate errors. Our results show that affirmative auditory feedback may improve one’s awareness of group activity at the expense of one’s awareness of his or her own activity. Negative auditory feedback may also improve group awareness, but simultaneously increase the perception of errors for both the group and the individual. In our second experiment, we compare two methods of associating sounds to invididuals in a co-located environment. Specifically, we compare localized sound, where each user has his or her own speaker, to coded sound, where users share one speaker, but the waveform of the sounds are vaired so that a different sound is played for each user. Results of this experiement reinforce the presence of tension between group awareness and individual focus found in the first experiment. User feedback suggests that users are more easily able to identify who caused a sound when either localized or coded sound is used, but that they are also more able to focus on their individual work. Our experiments show that, in general, auditory feedback can be used in co-located collaborative applications to support either individual work or group awareness, but not both simultaneously, depending on how it is presented.
exploring_non-speech_auditory_feedback_at_an_interactive_multi-user_tabletop.pdf
Ryall K, Esenther A, Everitt K, Forlines C, Morris MR, Shen C, Shipman S, Vernier FD. “iDwidgets: Parameterizing Widgets by User Identity”. Proceedings of Human-Computer Interaction - INTERACT 2005: IFIP TC13 International Conference. 2005 :1124-1128.Abstract
We introduce the concept of identity-differentiating widgets(iDwidgets), widgets parameterized by the identity of their user. Although multi-user applications have become more common, most support only traditional “single-user” widgets. By adding user-identity information we allow interactions with today’s widgets to be dynamically customized on a per-user basis in a group usage setting. The concept has inspired the design of new widgets as well. In this paper we describe example iDwidgets and define a conceptual framework based on what is being customized in the widget. iDwidgets can support novel interaction techniques in collaborative settings.
idwidgets.pdf
Forlines C, Shen C, Vernier FD. “Under My Finger: Human Factors in Pushing and Rotating Documents Across the Table”. Proceedings of Human-Computer Interaction - INTERACT 2005: IFIP TC13 International Conference. 2005 :994-997.Abstract
When passing a document to someone across a table, the person passing the document often rotates it to face the receiver. In this paper, we present the results of a user evaluation of three Push-and-Rotate schemes that offer different underlying control semantics for how an electronic document can automatically rotate as it is pushed across an interactive tabletop surface. The effects of document size are also discussed.
under_my_finger.pdf
Everitt K, Shen C, Ryall K, Forlines C. “DocuBits and Containers: Providing e-Document Micro-Mobility in a Walk-up Interactive Tabletop Environment”. Proceedings of Human-Computer Interaction - INTERACT 2005: IFIP TC13 International Conference. 2005 :998-1001.Abstract
A key challenge in supporting face-to-face collaborative work is e-document micro-mobility: supporting movement of digital content amongst shared display surfaces and personal devices at arbitrary levels of document granularity. Micro-mobility is a dexterity that physical paper artifacts afford - the ability to be handled with any position and placement, to be dismantled, cut and torn apart, marked up, reassembled and sorted. To support micro-mobility for electronic content and group work, we propose DocuBits and Containers. DocuBits offer the metaphor of a paper-cutter and a scanner for electronic documents. A portion of screen ´bits´from any application or any parts of visible display can be cut, grabbed, send and launched onto a different display surface or device with minimal interaction - merely three mouse/stylus click-select. Once arrived on the target display surface, DocuBits can be arbitrarily positioned, re-oriented, marked up, and pulled into other documents, or again send to other display surfaces. A Container is a composite draft of DocuBits and other documents, usually composed as the outcome of a collaborative meeting.
docubits_and_containers_providing_e-document_micro-mobility_in_a_walk-up_interactive_tabletop_environment.pdf
Forlines C, Shen C. “DTLens: Multi-User Tabletop Spatial Data Exploration”. Proceedings of the 18th Annual ACM Symposium on User Interface Software and Technology [Internet]. 2005 :119-122. Publisher's VersionAbstract
Supporting groups of individuals exploring large maps and design diagrams on interactive tabletops is still an open research problem. Today’s geospatial, mechanical engineering and CAD design applications are mostly single-user, keyboard and mouse-based desktop applications. In this paper, we present the design of and experience with DTLens, a new zoom-in-context, multiuser, two-handed, multi-lens interaction technique that enables group exploration of spatial data with multiple individual lenses on the same direct-touch interactive tabletop. DTLens provides a set of consistent interactions on lens operations, thus minimizes tool switching by users during spatial data exploration.
dtlens_multi-user_tabletop_spatial_data_exploration.pdf
Srinivasan U, Nepal S, Tian Q, Moghaddam B, Lesh N, Shen C, Huang TS. Visualization, Estimation and User-Modeling for Interactive Browsing of Personal Photo Libraries. In: Managing Multimedia Semantics. Hershey, PA: IRM Press ; 2005. pp. 193-222. Publisher's VersionAbstract
 
TR2002-53.pdf
2004
Everitt K, Forlines C, Ryall K, Shen C. Observations of a Shared Tabletop User Study, in ACM Conference on Computer Supported Cooperative Work (CSCW). Chicago, IL ; 2004. Publisher's VersionAbstract
We discuss the findings of two surveys, which presented respondents with a hypothetical situation regarding a conflict over either a paper or a digital document and solicited their free-form responses regarding possible outcomes of the situation. The results suggest conditions under which mechanisms to coordinate the outcome of such conflicts might be useful to include in groupware, as well as offering possibilities for what these mechanisms might be.
observation_of_a_shared_tabletop_user_study.pdf
Morris MR, Forlines C, Ryall K, Shen C. CSCW 2004 Conflict Resolution in Paper and Digital Worlds: Two Surveys of User Expectations, in ACM Conference on Computer Supported Cooperative Work (CSCW). Chicago, IL ; 2004. Publisher's VersionAbstract
We discuss the findings of two surveys, which presented respondents with a hypothetical situation regarding a conflict over either a paper or a digital document and solicited their free-form responses regarding possible outcomes of the situation. The results suggest conditions under which mechanisms to coordinate the outcome of such conflicts might be useful to include in groupware, as well as offering possibilities for what these mechanisms might be.
conflict_resolution.pdf
Moghaddam B, Tian Q, Lesh N, Shen C, Huang TS. "Visualization and User-Modeling for Browsing Personal Photo Libraries". International Journal of Computer Vision. 2004;56 (1/3) :109-130.Abstract
We present a user-centric system for visualization and layout for content-based image retrieval. Image features (visual and/or semantic) are used to display retrievals as thumbnails in a 2-D spatial layout or “configuration” which conveys all pair-wise mutual similarities. A graphical optimization technique is used to provide maximally uncluttered and informative layouts. Moreover, a novel subspace feature weighting technique can be used to modify 2-D layouts in a variety of context-dependent ways. An efficient computational technique for subspace weighting and re-estimation leads to a simple user-modeling framework whereby the system can learn to display query results based on layout examples (or relevance feedback) as provided by the user. The resulting retrieval, browsing and visualization engine can adapt to the users’s (time-varying) notions of content, context and preferences in presentation style and interactive navigation. Monte Carlo simulations with machine-generated layouts as well as pilot user studies have demonstrated the ability of this framework to model or “mimic” users, by automatically generating layouts according to their preferences.
visualization_and_user-modeling_for_browsing_personal_photo_libraries.pdf
Ringel M, Ryall K, Shen C, Forlines C, Vernier FD. "Release, Relocate, Reorient, Resize: Fluid Techniques for Document Sharing on Multi-User Interactive Tables". CHI '04 Extended Abstracts on Human Factors in Computing Systems [Internet]. 2004. Publisher's VersionAbstract
Group work frequently involves transitions between periods of active collaboration and periods of individual activity. We aim to support this typical work practice by introducing four tabletop direct-manipulation interaction techniques that can be used to transition the status of an electronic document from private to group-accessible. After presenting our four techniques – release, relocate, reorient, and resize – we discuss the results of an empirical study that compares and evaluates these mechanisms for sharing documents in a co-located tabletop environment.
release_relocate_reorient_resize.pdf
Shen C, Vernier FD, Forlines C, Ringel M. “DiamondSpin: An Extensible Toolkit for Around-the-Table Interaction”. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems [Internet]. 2004 :167-174. Publisher's VersionAbstract
DiamondSpin is a toolkit for the efficient prototyping of and experimentation with multi-person, concurrent interfaces for interactive shared displays. In this paper, we identify the fundamental functionality that tabletop user interfaces should embody, then present the toolkit’s architecture and API. DiamondSpin provides a novel realtime polar to Cartesian transformation engine that has enabled new, around-the-table interaction metaphors to be implemented. DiamondSpin allows arbitrary document positioning and orientation on a tabletop surface. Polygonal tabletop layouts such as rectangular, octagonal, and circular tabletops can easily be constructed. DiamondSpin also supports multiple work areas within the same digital tabletop. Multi-user operations are offered through multithreaded input event streams, multiple active objects, and multiple concurrent menus. We also discuss insights on tabletop interaction issues we have observed from a set of applications built with DiamondSpin.
diamondspin.pdf
Ma Z, Shao H-R, Shen C. “A New Multi-Path Selection Scheme for Video Streaming on Overlay Networks”, in IEEE International Conference on Communications (ICC). Paris, France: IEEE ; 2004.Abstract
This paper presents a new multi-path selection scheme for video streaming on overlay networks. Our scheme uses an overlay network architecture that makes minimal assumptions about the knowledge of the underlying network. We first propose a new QoS metric link correlation and a path correlation model for multi-path selection problem. After discussing the tractability of minimal correlation multi-path selection problem, we present an efficient algorithm called correlation cost routing to select multi-path in overlay networks. The simulation results show that the average peak signal-to-noise ratio (PSNR) of the transmitted multiple descriptions coding (MDC) video using our multi-path selection algorithm improves by up to 3.2 dB over maximally link-disjoint multi-path selection method. Furthermore our new algorithm is more efficient than previous methods since it shares the same complexity with Dijsktra algorithm.
a_new_multi-path_selection_scheme_for_video_streaming.pdf
Ryall K, Forlines C, Shen C, Morris MR. “Exploring the Effects of Group Size and Table Size on Interactions with Tabletop Shared-Display Groupware”. Proceedings of CSCW 2004 [Internet]. 2004 :284-293. Publisher's VersionAbstract
Interactive tabletops have been previously proposed and studied in the domain of co-located group applications. However, little fundamental research has been done to explore the issue of size. In this paper we identify a number of size considerations for tabletop design, and present an experiment to explore some of these issues, in particular the effects of group size and table size on the speed at which the task was performed, the distribution of work among group members, issues of shared resources, and user preference for table size. Our findings shed light on (1) how work strategies are affected by group size, (2) how social interaction varies with respect to table size, and (3) how the speed of task performance is influenced by group size but not by table size. In addition, our experiments revealed that for larger groups, designers might need to add additional vertical displays for shared information. This finding opens the door for extending singledisplay groupware to shared-display groupware settings that involve multiple, shared displays.
exploring_the_effects_of_group_size_and_table_size_on_interactions.pdf
Morris MR, Ryall K, Shen C, Forlines C, Vernier FD. “Beyond Social Protocols: Multi-User Coordination Policies for Co-located Groupware”. Proceedings of CSCW 2004 [Internet]. 2004 :262-265. Publisher's VersionAbstract
The status quo for co-located groupware is to assume that ”social protocols” (standards of polite bhavior) are sufficient to coordinate the actions of a group of users; however, prior studies of groupware use as well as our own observations of groups using a shared tabletop display suggest potential for improving groupware interfaces by incorporating coordination policies - direct manipulation mechanisms for avoiding and resolving conflicts. We discuss our observations of group tabletop usage and present our coordination framework. We conclude with example usage scenarios and discuss future research suggested by this framework.
beyond_social_protocols.pdf
2003
Shao H-R, Shen C, Gu D, Zhang J, Orlik P. Dynamic Resource Control for High-Speed Downlink Packet Access Wireless Channel, in 23rd International Conference on Distributed Computing Systems Workshops (ICDCSW'03). Providence, RI ; 2003. Publisher's VersionAbstract
It is a challenging task to provide Quality of Service (QoS) control for a shared high-speed downlink packet access (HSDPA) wireless channel. In this paper, we first propose a new dynamic resource control framework integrated with adaptive modulation and coding (AMC) and hybrid automatic repeat request (H-ARQ) to support class-based multimedia applications over HSDPA wireless channels. Then we present a new scheduling algorithm, Delay-sensitive Dynamic Fair Queueing (DSDFQ), to meet delay requirements of multimedia applications as well as maintain high network efficiency. The proposed approach can easily adapt to load fluctuations of different traffic classes and varying wireless channel conditions caused by user mobility, fading and shadowing. Performance evaluation shows the advantage of our proposed approach.
dynamic_resource_control.pdf
Shen C, Lesh N, Vernier FD. "Personal Digital Historian: Story Sharing Around The Table". ACM Interactions [Internet]. 2003;10 (2) :15-22. Publisher's Version personal_digital_historian_story_sharing_around_the_table.pdf
Zhou J, Shao H-R, Shen C, Sun M-T. "FGS Enhancement Layer Truncation with Minimized Intra-Frame Quality Variation", in IEEE International Conference on Multimedia and Expo (ICME). ; 2003.Abstract
This paper proposes an enhancement layer truncation scheme for the Fine-Granularity-Scalability (FGS) video. Our target is to minimize the quality variation of different parts within each frame when the last transmitted enhancement layer is truncated according to the available network bandwidth. This paper proposes an enhancement layer truncation scheme for the Fine-Granularity-Scalability (FGS) video. Our target is to minimize the quality variation of different parts within each frame when the last transmitted enhancement layer is truncated according to the available network bandwidth.
fgs_enhancement_layer_truncation.pdf
Shen C, Everitt KM, Ryall K. "UbiTable: Impromptu Face-to-Face Collaboration on Horizontal Interactive Surfaces". UbiComp 2003: The Fifth International Conference on Ubiquitous Computing [Internet]. 2003 :281-288. Publisher's VersionAbstract
Despite the mobility enabled by the plethora of technological tools such as laptops, PDA and cell phones, horizontal flat surfaces are still extensively used and much preferred for on-the-move face-to-face collaboration. Unfortunately, when digital documents need to be shared during collaboration, people are still mostly constrained to display surfaces that have been designed for single users, such as laptops and PDAs. Technologically there is a lack of computational support for shared digital document access, browsing, visualization and manipulation on horizontal surfaces. We believe support for such serendipitous meetings will play a critical role in future ubiquitous computing spaces. Our UbiTable project examines the design space of tabletops used as scrap displays. Scrap displays support kiosk-style walk-up interaction for impromptu face-to-face collaboration. Our design offers the affordances of a physical table. It provides the flexibility by allowing users to layout shared documents with desired orientation and position; at the same time it augments traditional paper-based interactions by providing a flexible gradient or shades of sharing semantics. UbiTable addresses visual accessibility vs. electronic accessibility of documents, an issue which is critical to ubiquitous environments.
ubitable.pdf

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