Sign In

Communications of the ACM

71 - 80 of 286 for bentley

Understanding Video Rewatching Experiences

New video platforms have enabled a wide variety of opportunities for rewatching video content. From streaming sites such as Netflix, Hulu, and HBO Now, to the proliferation of syndicated content on cable and satellite television, to new streaming devices for the home such as Roku and Apple TV, there are countless ways that people can rewatch movies and television shows. But what are people doing? We set out to understand current rewatching practices across a variety of devices and services. Through an online, open-ended survey to 150 diverse people and in- depth, in-person interviews with 10 participants, we explore current rewatching behaviors. We quantify the types of content that are being rewatched as well as qualitatively explore the reasons and contexts behind rewatching. We conclude with key implications for the design of new video systems to promote rewatching behaviors.


The 32 Days of Christmas: Understanding Temporal Intent in Image Search Queries

Temporal terms, such as 'winter', 'Christmas', or 'January' are often used in search queries for personal images. But how do people's memories and perceptions of time match with the actual dates when their images were captured? We compared the temporal terms that 74 Flickr users used to search their own photo collections, and compared them to the date captured data in the target image. We also conducted a larger study across several billion images, comparing user-applied tags for holidays and seasons to the dates the images were captured. We demonstrate that various query terms and tags can be in conflict with the actual dates photos were taken for specific types of temporal terms up to 40% of the time. We will conclude by highlighting implications for search systems where users are querying for personal content by date.


FitPlay Games: Increasing Exercise Motivation Through Asynchronous Social Gaming

Many factors contribute to people's physical inactivity, but among the leading factors is a lack of motivation. Fitness trackers have been shown to encourage an increase in exercise, but they are frequently abandoned within a few short months. We developed our asynchronous-play social gaming platform, FitPlay Games, to fill the gap in motivation left by current fitness trackers. By providing users with a variety of asynchronous cooperative and competitive gaming styles, we enable them to find a motivation technique that works best for their lifestyle and fitness prowess. The platform encourages prolonged use of fitness trackers, helping users to have more healthy lifestyles. Individual games are designed to allow both the novice and the maven to have a chance at winning, leveling the playing field, and increasing motivation to win. The effectiveness, usability, and enjoyability of the social games will be assessed, with an emphasis on understanding differences in play habits due to gender and lifestyle.


Embedding User Understanding in the Corporate Culture: UX Research and Accessibility at Yahoo

This case study shows how a UX Research organization created a company-wide user first culture, aligned the strategy of multiple products to align with real user needs, and improved product usability in a global company with over 1 billion monthly web and mobile app users. We will describe the team, its organization and role, and specific ways research is conducted to positively impact product development. As the organization and function of research teams in industry has been largely opaque to the broader CHI community, we hope that this case study will provide deep insight and foster a larger conversation about the role of UX Research at scale and the best ways to organize and deliver that research for maximum effect.


Examining Unlock Journaling with Diaries and Reminders for In Situ Self-Report in Health and Wellness

In situ self-report is widely used in human-computer interaction, ubiquitous computing, and for assessment and intervention in health and wellness. Unfortunately, it remains limited by high burdens. We examine unlock journaling as an alternative. Specifically, we build upon recent work to introduce single-slide unlock journaling gestures appropriate for health and wellness measures. We then present the first field study comparing unlock journaling with traditional diaries and notification-based reminders in self-report of health and wellness measures. We find unlock journaling is less intrusive than reminders, dramatically improves frequency of journaling, and can provide equal or better timeliness. Where appropriate to broader design needs, unlock journaling is thus an overall promising method for in situ self-report.


On-Demand Biometrics: Fast Cross-Device Authentication

We explore the use of a new way to log into a web service, such as email or social media. Using on-demand biometrics, users sign in from a browser on a computer using just their name, which sends a request to their phone for approval. Users approve this request by authenticating on their phone using their fingerprint, which completes the login in the browser. On-demand biometrics thus replace passwords or temporary access codes found in two-step verification with the ease of use of biometrics. We present the results of an interview study on the use of on-demand biometrics with a live login backend. Participants perceived our system as convenient and fast to use and also expressed their trust in fingerprint authentication to keep their accounts safe. We motivate the design of on-demand biometrics, present an analysis of participants' use and responses around general account security and authentication, and conclude with implications for designing fast and easy cross-device authentication.


"I thought she would like to read it": Exploring Sharing Behaviors in the Context of Declining Mobile Web Use

The use of applications on mobile devices has changed dramatically over the past few years. While web browsing was once a common activity, it's now reported that 86% of time on mobile phones is in apps other than the browser. We set out to understand how the mobile web was currently fitting into people's lives and what web sessions looked like. Finding a dramatic reduction in mobile web revisi-tation rates compared to previous work and that a large number of sessions comprised single page views, we then studied how web content was shared with others in mobile messaging, the source of many single page sessions. The HCI community has not heavily studied this sharing activity that many people perform daily. We conclude with design implications for new mobile applications from our two studies with a combined 287 participants where we studied actual logs of mobile web use and link sharing behavior.


Exploring Privacy Preservation in Outsourced K-Nearest Neighbors with Multiple Data Owners

The k-nearest neighbors (k-NN) algorithm is a popular and effective classification algorithm. Due to its large storage and computational requirements, it is suitable for cloud outsourcing. However, k-NN is often run on sensitive data such as medical records, user images, or personal information. It is important to protect the privacy of data in an outsourced k-NN system. Prior works have all assumed the data owners (who submit data to the outsourced k-NN system) are a single trusted party. However, we observe that in many practical scenarios, there may be multiple mutually distrusting data owners. In this work, we present the first framing and exploration of privacy preservation in an outsourced k-NN system with multiple data owners. We consider the various threat models introduced by this modification. We discover that under a particularly practical threat model that covers numerous scenarios, there exists a set of adaptive attacks that breach the data privacy of any exact k-NN system. The vulnerability is a result of the mathematical properties of k-NN and its output. Thus, we propose a privacy-preserving alternative system supporting kernel density estimation using a Gaussian kernel, a classification algorithm from the same family as k-NN. In many applications, this similar algorithm serves as a good substitute for k-NN. We additionally investigate solutions for other threat models, often through extensions on prior single data owner systems.


Reducing replication bandwidth for distributed document databases

With the rise of large-scale, Web-based applications, users are increasingly adopting a new class of document-oriented database management systems (DBMSs) that allow for rapid prototyping while also achieving scalable performance. Like for other distributed storage systems, replication is important for document DBMSs in order to guarantee availability. The network bandwidth required to keep replicas synchronized is expensive and is often a performance bottleneck. As such, there is a strong need to reduce the replication bandwidth, especially for geo-replication scenarios where wide-area network (WAN) bandwidth is limited.

This paper presents a deduplication system called sDedup that reduces the amount of data transferred over the network for replicated document DBMSs. sDedup uses similarity-based deduplication to remove redundancy in replication data by delta encoding against similar documents selected from the entire database. It exploits key characteristics of document-oriented workloads, including small item sizes, temporal locality, and the incremental nature of document edits. Our experimental evaluation of sDedup with three real-world datasets shows that it is able to achieve up to 38X reduction in data sent over the network, significantly outperforming traditional chunk-based deduplication techniques while incurring negligible performance overhead.