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Communications of the ACM


81 - 90 of 371 for bentley


Efficient Location-Aware Web Search

Mobile search is quickly becoming the most common mode of search on the internet. This shift is driving changes in user behaviour, and search engine behaviour. Just over half of all search queries from mobile devices have local intent, making location-aware search an increasingly important problem. In this work, we compare the efficiency and effectiveness of two general types of geographical search queries, range queries and k nearest neighbor queries, for common web search tasks. We test state-of-the-art spatial-textual indexing and search algorithms for both query types on two large datasets. Finally, we present a rank-safe dynamic pruning algorithm that is simple to implement and use with current inverted indexing techniques. Our algorithm is more efficient than the tightly coupled best-in-breed hybrid indexing algorithms that are commonly used for top-k spatial textual queries, and more likely to find relevant documents than techniques derived from range queries.

2015-12-08
https://dl.acm.org/ft_gateway.cfm?id=2838933&dwn=1

Learning from the experts: enabling and studying DIY development of location-based visitor experiences

In this paper we show how -- with the aid of enabling technology -- creative Location Based Experiences can be developed for visitors by non-technical professionals from the cultural heritage sector. We look at how these "Place Experts" approach and adopt web technologies to create and publish experiences including the roles they take on, the processes they adopt, and the way they appropriate the technology. We describe our short and long-term research engagements with the cultural heritage sector over the last three years and introduce Wander Anywhere, the website developed to enable this research. We find that place experts typically follow a four stage process in their engagement with location-based experiences, moving from comprehension to translation, development and finally approval. We suggest implications for the processes and technologies that might be employed by others seeking to support a similar type of engagement.

2015-09-07
https://dl.acm.org/ft_gateway.cfm?id=2805838&dwn=1

Visualization of time-series sensor data to inform the design of just-in-time adaptive stress interventions

We investigate needs, challenges, and opportunities in visualizing time-series sensor data on stress to inform the design of just-in-time adaptive interventions (JITAIs). We identify seven key challenges: massive volume and variety of data, complexity in identifying stressors, scalability of space, multifaceted relationship between stress and time, a need for representation at multiple granularities, inter-person variability, and limited understanding of JITAI design requirements due to its novelty. We propose four new visualizations based on one million minutes of sensor data (n=70). We evaluate our visualizations with stress researchers (n=6) to gain first insights into its usability and usefulness in JITAI design. Our results indicate that spatio-temporal visualizations help identify and explain between- and within-person variability in stress patterns and contextual visualizations enable decisions regarding the timing, content, and modality of intervention. Interestingly, a granular representation is considered informative but noise-prone; an abstract representation is the preferred starting point for designing JITAIs.

2015-09-07
https://dl.acm.org/ft_gateway.cfm?id=2807537&dwn=1

Sharing (and Discussing) the Moment: The Conversations that Occur Around Shared Mobile Media

Today's smartphones enable rich, media-enhanced conversations. Millions of photos and billions of messages are shared each day on smartphones. But how, exactly, are images and web links being used in mobile conversations? And what does this mean for the design of new mobile communications applications? We set out to learn how people currently share and discuss mobile media by performing a detailed content analysis of 109 photos and links that were shared in 2,779 messages using a mobile messaging application deployed in the United State and Taiwan. Through our analysis of these conversations, we show how mobile media is used to experience the moment together, to fill in the visual details, to provide background context, and to exchange information. We then discuss our results and provide two designs inspired by our findings.

2015-08-24
https://dl.acm.org/ft_gateway.cfm?id=2785868&dwn=1

Visualising Multi-objective Populations with Treemaps

Visualising populations of solutions is an important aspect of evolutionary computation (EC), allowing an algorithm user to evaluate the performance of an algorithm and a decision maker to understand the solution set from which they must choose an operating solution. We present a novel approach to visualising multi-objective data, employing treemaps to display both solutions and objectives. We define a simple approach to constructing a tree that can represent a multi-objective population in terms of dominance, and illustrate several ways in which it can be used. Examples are provided that reveal characteristics of objective space, as well as combining information about the parameter space component of the population. The paper concludes with a discussion about the further potential of treemaps within EC.

2015-07-11
https://dl.acm.org/ft_gateway.cfm?id=2768445&dwn=1

"I'm just on my phone and they're watching TV": Quantifying mobile device use while watching television

In recent years, mobile devices have become a part of our daily lives--much like television sets had over the second half of the 20th century. Increasingly, people are using mobile devices while watching television. We set out to understand this behavior on a minute-by-minute quantified level as well as users' motivations and purposes of device use while watching television. We conducted a novel mixed-methods study inside seven households with fourteen instrumented phone and tablet devices, capturing all app launches and app use durations, correlated with the moment in the television program when they occurred. Surprisingly, we found little difference between the volume of device use during programs and commercials. Our two main findings are that 1) participants often joined family members in the TV room to physically be together; when they lack interest in the program, they spend the majority of the show on a secondary device and watch TV only during key moments. 2) Virtually none of participants' app and web use during TV consumption was directly related to the running show. With our study, we set the stage for larger-scale investigations into the details of mobile interactions while watching television. Our novel method will aid future work of the community as a means of fully understanding multi-device use alongside television consumption.

2015-06-03
https://dl.acm.org/ft_gateway.cfm?id=2745210&dwn=1

Investigating mobile broadband affordability in developing countries: a cross-national comparison

This paper aims to identify and understand whether national policy initiatives, regulatory measures, or governance practices increase a developing nation's mobile broadband affordability. For this purpose, a cross-national multiple regression analysis of non-OECD countries is used. The results revealed that when controlling for wealth, education and other factors, competition to provide mobile services, financial investment in ICTs, and income inequality are all important variables for determining mobile broadband affordability. Findings suggest that service providers and other stakeholders are still recouping the cost of deploying the infrastructure necessary to provide mobile services, and have not yet achieved the economies of scale required for the price of mobile broadband to begin to fall, at least in the developing world. This paper provides contributions to academia, industry, and policymakers.

2015-05-15
https://dl.acm.org/ft_gateway.cfm?id=2737875&dwn=1

Reducing the Stress of Coordination: Sharing Travel Time Information Between Contacts on Mobile Phones

We explore the everyday use of a new abstraction for mo-bile location-sharing. By sharing the travel time between contacts calculated for walking, transit, and driving, we have enabled users to more easily coordinate meeting up and planning family obligations. Specifically, our participants reported that the information helped to lower the stress of these activities and provided reassurance of the arrival times of their close friends and family. In this paper, we describe our system, motivate its design, and explore results from a 20-user, 21-day field trial showing the use-fulness of the abstraction as well as attitudes towards privacy when sharing travel times with close friends or family.

2015-04-18
https://dl.acm.org/ft_gateway.cfm?id=2702208&dwn=1

The Composition and Use of Modern Mobile Phonebooks

Over the past decade, the mobile phonebook has evolved from a relatively short list of people that one calls and texts to a many-hundred person list of aggregated contacts from around the web. This is happening at a time when an increasing number of mobile applications are relying on the mobile phonebook to create one's social network in their services. Through a large-scale study of the phonebooks of 200 diverse participants, containing 65,940 contacts, we set out to understand today's mobile contact lists. Our participants reported that they did not recognize the names of 29% of their contacts and we found that the most frequently contacted five contacts represent greater than 80% of all calls and text messages with phonebook contacts. We conclude with implications for the design of mobile applications that rely on phonebook data.

2015-04-18
https://dl.acm.org/ft_gateway.cfm?id=2702182&dwn=1

"It's kind of like an extra screen for my phone": Understanding Everyday Uses of Consumer Smart Watches

The CHI, Ubicomp, and UIST communities have been studying watch-based interactions for many years. While much of this work has been technical or focused on interaction techniques in the lab, now smart watch devices are available directly to consumers from a variety of manufacturers. However, little has been studied as to why people adopt these devices and the real-world problems that they are solving in their lives. We set out to explore current smart watch use in an interview-based study of five diverse participants. We will use data from this study to help design and develop new smart watch applications.

2015-04-18
https://dl.acm.org/ft_gateway.cfm?id=2732931&dwn=1