The Effects of Network Delays on Group Work in Real-Time Groupware

Gutwin, Carl

doi:10.1007/0-306-48019-0_16

Cited by 40 publications

(50 citation statements)

References 13 publications

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“…User studies have shown that jitter leads to a further decrease in productivity and an increase in user errors. 12 In addition to physical-layer transmission delays and end-to-end software path lengths, technologies such as firewalls, virtual private networks and other overlay networks, and lossy wireless networks add latency and other hurdles. While our simulation does not model these factors, their inclusion would have further biased our results against thin clients.…”

Section: Discussionmentioning

confidence: 99%

Quantifying Interactive User Experience on Thin Clients

2006

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Computer P u b l i s h e d b y t h e I E E E C o m p u t e r S o c i e t yclients offer a good computing experience. As network quality degrades, interactive performance suffers.It is latency-not bandwidth-that is the greater challenge. Tightly coupled tasks such as graphics editing suffer more than loosely coupled tasks such as Web browsing. The combination of worst anticipated network quality and most tightly coupled tasks will determine whether a thin-client approach is satisfactory for an organization.Stateless thick clients, an alternative to thin-client computing, preserve many of the benefits of thin-client computing but eliminate its acute sensitivity to network latency. This alternative approach achieves this improvement by asynchronously transferring more runtime state to a client and executing from that state on a local processor. TIME-SHARING REDUXIn his 1983 classic, "Hints for Computer System Design," 2 Butler Lampson offered the following quote from Jim Morris: "The nicest thing about the Alto is that it doesn't run faster at night." This quote succinctly captures the joy of a time-sharing user who has just discovered the crisp, unvarying performance of a personal computer on highly interactive tasks. Gone is the pain of sluggish interactive response during periods of peak load. By colocating a processor with each user, personal computing offers a computing experience that is unaffected by the actions of other users.The adequacy of thin-client computing is highly variable and depends on both the application and the available network quality. For intensely interactive applications, a crisp user experience may be hard to guarantee. An alternative-stateless thick clientspreserves many of the benefits of thin-client computing but eliminates its acute sensitivity to network latency. Niraj Tolia, David G. Andersen, and M. SatyanarayananCarnegie Mellon University A fter a few false starts in the past decade, thinclient computing is finally gaining serious attention and acceptance among large and medium-size companies. For example, recent Wall Street Journal articles (17 Jan. 2005, 3 Feb. 2005) predicted that more than 3 million enterprise desktops, amounting to 10 percent of the market, will be thin clients by 2008. These articles also mention Time-Warner, Wal-Mart, and the Pentagon as examples of enterprises that are adopting thin clients in significant numbers. Microsoft is also reported to be close to releasing a stripped-down version of Windows XP that transforms an old PC into a thin client (www. brianmadden.com; 18 April 2005).A thin client consists of a display, keyboard, and mouse combined with sufficient processing power and memory for graphical rendering and network communication with a compute server using a specialized protocol. All application and operating system code is executed on the server. The client has no long-term user state and needs no disk. A standard PC can be made to function as a thin client through software such as Virtual Network Computing (VNC). 1 We describe an approach ...

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Section: Discussionmentioning

confidence: 99%

Quantifying Interactive User Experience on Thin Clients

2006

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“…Work in the area of system response time suggests that delays in the range of 80-100 ms will not be noticeable by the majority of users. In a study by Mauve et al [2004] users did not notice network lags below 120 ms, thus, depending on the applications, tolerable latencies might be even higher than 80-100 ms. Gutwin [2002] showed that in a simple coordination task a delay of 200 ms already significantly increased the error rates. However, the examples used in such studies are primarily targeting humanmachine interaction or manipulation of objects and do not address the issue of self-perception and self-monitoring.…”

Section: R2: Low Latency and High Frame Ratementioning

confidence: 99%

Realizing a low-latency virtual reality environment for motor learning

Waltemate

Hülsmann

Pfeiffer

et al. 2015

Proceedings of the 21st ACM Symposium on Virtual Reality Software and Technology

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Figure 1: Real-time feedback using a virtual mirror requires an immersive Virtual Reality environment that provides full-body motion capturing, motion analysis, and realistic character rendering at a low end-to-end latency. AbstractVirtual Reality (VR) has the potential to support motor learning in ways exceeding beyond the possibilities provided by real world environments. New feedback mechanisms can be implemented that support motor learning during the performance of the trainee and afterwards as a performance review. As a consequence, VR environments excel in controlled evaluations, which has been proven in many other application scenarios.However, in the context of motor learning of complex tasks, including full-body movements, questions regarding the main technical parameters of such a system, in particular that of the required maximum latency, have not been addressed in depth. To fill this gap, we propose a set of requirements towards VR systems for motor learning, with a special focus on motion capturing and rendering. We then assess and evaluate state-of-the-art techniques and technologies for motion capturing and rendering, in order to provide data on latencies for different setups. We focus on the end-to-end latency of the overall system, and present an evaluation of an exemplary system that has been developed to meet these requirements.

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“…Delay is a fact of life in real-world distributed applications because information must be transmitted across a network and processed at the other end before it can be displayed [9]. There are two main types of delay: latency and jitter.…”

Section: Network Delay and Its Effects On Collaborationmentioning

confidence: 99%

The effects of local lag on tightly-coupled interaction in distributed groupware

Stuckel

Gutwin

2008

Proceedings of the 2008 ACM Conference on Computer Supported Cooperative Work

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Tightly-coupled interaction is shared work in which each person's actions immediately and continuously influence the actions of others. Tightly-coupled collaboration is a hallmark of expert behavior in face-to-face activity, but becomes extremely difficult to accomplish over distributed groupware. The main cause of this difficulty is network delay that disrupts people's ability to synchronize their actions with another person. In this paper we report on two studies that explore local lag as a way of reducing this problem. When applied to visual feedback, local lag synchronizes the visual environments of the local and remote clients, preventing one person from getting ahead of the other. We tested the effects of local lag in several delay conditions: we found that the technique significantly improved performance, and that users did not rate local lag as more difficult or frustrating to use. Our studies improve our understanding of local lag and of how it improves tightly-coupled interaction in distributed groupware.

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The Effects of Network Delays on Group Work in Real-Time Groupware

Cited by 40 publications

References 13 publications

Quantifying Interactive User Experience on Thin Clients

Quantifying Interactive User Experience on Thin Clients

Realizing a low-latency virtual reality environment for motor learning

The effects of local lag on tightly-coupled interaction in distributed groupware

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