Published papers

© 2016 ACM. As users enjoy their computing with an increasing number of devices, applications and services, and connected other users, users' attention is getting the most precious resource in computing due to increasing information fragments provided proactively. Research on user's attention management and especially interruptibility have been accelerated in the recent years. After clarifying some recent background computing trends, this paper focuses on those researches areas, specifies several possible opportunities in the area, and proposes 3 key future opportunities that include being a layer and platform, communication with industries, and intersection with research areas. This paper aims to motivate active discussion on how we can make our research flourish in rather longer term.

© 2016 ACM. We propose a system for improving the answer rate to ES inquiry to reduce the user's mental burden by detectin breakpoints in user's physical activity and pushing notification in such timings. We conducted an in-The-wild use study with 30 participants for 4-days. The results reveale the effectiveness of breakpoint-based notification delivery In the best case, 70.0% improvement in user's respons time to notifications was observed at a transition to th user's activity from "walking" to "stationary".

LiveLabs is an urban scale research testbed in Singapore. It is currently in the process of design, implementation and deployment at real-life urban spaces like a sprawling university campus, a shopping mall, an airport and an amusement park; where real smartphone users are being incentivized to participate in large scale consumer behavioral trials and experiments. The scale of the testbed needs careful research on multiple aspects of mobile computing - including smart application and UI design, smartphone power management, handling user privacy and so on. In this demonstration paper, we outline some important aspects of ongoing research, for handling some key technical challenges of a real city-scale smartphone testbed. © 2014 IEEE.

We propose "MobileSocket", a new simple user-level enhanced socket library written in pure-Java. MobileSocket provides Java applications with application layer mobility and connection continuity in order to support their continuous operation. Existing Java applications Can attain socket-level mobility and connection continuity without any modification to their sourcc code merely by replacing Java standard socket class with our MobileSocket. Two mechanisms inside the library, Dynamic Socket Switching (DSS) and Application Layer Window (ALW) provide application layer mobility and connection continuity without any kernel-level modifications or additional proxy software. In this paper, we describe design and implementation of MobileSocket and show evaluated results on our systems with FreeBSD.

© 1999 IEEE. This paper proposes "MobileSocket" which realizes session layer communication continuity support for Java Applications towards the continuous operations for mobile applications. In the mobile computing environment where mobile hosts move around the network even during communications with the remote, maintenance of the communication continuity between the applications is significant. Not only mobility support but virtual circuit continuity support is required for communication continuity. Existing approaches have not provided the complete communication continuity for applications. "MobileSocket" is a user-level enhanced socket library written in Java, and provides library-based session layer mobility and virtual circuit continuity support for applications. Two mechanisms, dynamic socket switching (DSS) and the application layer window (ALW) were developed for MobileSocket and enable a simple implementation. The MobileSocket applications can be used in Java mobile applications and the agents, as well as for ordinary network applications. In this paper, after we clarify the communication continuity and existing approaches, we present the MobileSocket design, mechanism, and results of evaluation.

We propose "MobileSocket", a new simple user-level enhanced socket library written in pure-Java. MobileSocket provides Java applications with application layer mobility and connection continuity in order to support their continuous operation. Existing Java applications can attain socket-level mobility and connection continuity without any modification to their source code merely by replacing Java standard socket class with our MobileSocket. Two mechanisms inside the library, Dynamic Socket Switching (DSS) and Application Layer Window (ALW) provide application layer mobility and connection continuity without any kernel-level modifications or additional proxy software. In this paper, we describe design and implementation of MobileSocket and show evaluated results on our systems with FreeBSD.

© 2018 Association for Computing Machinery. Towards wellbeing-awareness in computing, researches for estimating users' emotions using smartphone sensor data have been actively conducted as smartphones are getting more and more ubiquitous. Most studies have constructed emotion estimation models based on machine learning with contextual data from the smartphones and user's self-reporting ground truth label often collected via Experience Sampling Method (ESM). However, snice our emotion changes frequently in our daily lives, trying to collect the ground truth of such volatile emotions leads a storm of ESMs which could be burden to the users. In order to find better ESM methods, we propose and compare 3 ESMs, namely Randomized ESM that executes in randomly timings, Trigger ESM that executes when the user's behavior changes, and Unlocking ESM that sets up ESM on the unlocking screen. We constructed various emotional estimation models with four types of time granularity (1 day, 1/3 day, 3 hours, 1 hour) in four weeks experience with eight persons. As for the response rate, Unlocking ESM was the highest. In addition, it was clear that Unlocking ESM had the highest estimation accuracy in most cases.