研究者詳細 - 徳田　英幸

論文 - 徳田　英幸

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Real-world product deployment of adaptive push notification scheduling on smartphones

Okoshi T., Tsubouchi K., Tokuda H.

Proceedings of the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining （Proceedings of the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining） 2792 - 2800 2019年07月

ISSN 9781450362016

The limited attentional resource of users is a bottleneck to delivery of push notifications in today's mobile and ubiquitous computing environments. Adaptive mobile notification scheduling, which detects opportune timings based on mobile sensing and machine learning, has been proposed as a way of alleviating this problem. However, it is still not clear if such adaptive notifications are effective in a large-scale product deployment with real-world situations and configurations, such as users' context changes, personalized content in notifications, and sudden external factors that users commonly experience (such as breaking news). In this paper, we construct a new interruptibility estimation and adaptive notification scheduling with redesigned technical components. From the deploy study of the system to the real product stack of Yahoo! JAPAN Android application and evaluation with 382,518 users for 28 days, we confirmed several significant results, including the maximum 60.7% increase in the users' click rate, 10 times more gain1compared to the previous system, significantly better gain in the personalized notification content, and unexpectedly better performance in a situation with exceptional breaking news notifications. With these results, the proposed system has officially been deployed and enabled to all the users of Yahoo! JAPAN product environment where more than 10 million Android app users are enjoying its benefit.

Access to Document (DOI)

Cruisers: An automotive sensing platform for smart cities using door-to-door garbage collecting trucks

Chen Y., Nakazawa J., Yonezawa T., Tokuda H.

Ad Hoc Networks （Ad Hoc Networks） 85 32 - 45 2019年03月

ISSN 15708705

Due to the advance in information and communication technologies, smart cities have become an increasingly appealing vision. One indispensable basis in the research, development and implementation of smart cities is urban sensing technology. Automotive sensing is a novel urban sensing technology that equips sensors to vehicles, like buses, taxi cabs or garbage trucks and utilizes their mobility to help to conduct urban sensing tasks. In this paper, we present Cruisers, an automotive sensing platform for smart cities, based on the following ideas: a) Garbage collecting trucks are used to host sensors, b) Cellular communication network is used to deliver sensed data to servers, and c) Proxy server(s) are adopted to convert the format of sensed data to required ones, such as sampling rate, spatial interval or pub/sub protocol. To validate the feasibility of Cruisers, we implement a real system that consists of 66 customized sensing modulars integrating typical environmental and mobility sensors and deploy them into the garbage collecting trucks at Fujisawa, a medium-sized city in Japan. Performance evaluation is conducted to investigate the performance of Cruisers in terms of scalability, data publishing delay and spatial coverage.

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Real-world large-scale study on adaptive notification scheduling on smartphones

Okoshi T., Tsubouchi K., Tokuda H.

Pervasive and Mobile Computing （Pervasive and Mobile Computing） 50 1 - 24 2018年10月

ISSN 15741192

Human attention has bottlenecked today's ubiquitous computing environment where users are consuming increasing amounts of information from numerous applications and services. Since the system-to-user provision of information is becoming more proactive, mainly via push notifications that often cause interruption at the users’ side, attention management is becoming very important. Despite the many existing studies concerned with detecting opportune moments to present such push information to the users (in a way that preserves the user's attention and lowers their cognitive load and frustration), there is little evaluation of such systems in the real-world production environments. Overlooked areas of study also include the examination of real users and notification contents. In this paper, we present various results from the first extensive evaluation on user's interruptibility and engagement in the real-world environment with a market-leading smartphone application that boasts a large number of users, including real notification content on the application. Following our previous mobile-sensing and machine learning-based interruptibility estimation approach, which was an effective study in its own right (Okoshi et al., 2015 [18,19]), we embedded a logic with the same approach in the “Yahoo! JAPAN” Android app (one of the most popular applications on the national market). The results from our large-scale in-the-wild user study (that included more than 680,000 users and spanned three weeks) indicate that, in most cases, delaying the notification delivery until an interruptible moment is detected is beneficial to users. The practice results in significant reduction of user response time (49.7%) when compared to delivering the notifications immediately. We observed a higher number of notifications opened in our system and constant improvement in user engagement levels throughout the entire study period. We also observed differences in click rates among different days and time among users with different attributes (e.g., age, gender, and occupation). Additional evaluation of our revised system, which can train and distribute different models for weekdays and weekends, improved the click rates during weekends. This negated the performance degradation previously observed during weekends.

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Evaluating the spatio-temporal coverage of automotive sensing for smart cities

Chen Y., Yonezawa T., Nakazawa J., Tokuda H.

2017 10th International Conference on Mobile Computing and Ubiquitous Network, ICMU 2017 （2017 10th International Conference on Mobile Computing and Ubiquitous Network, ICMU 2017） 2018-January 1 - 5 2018年04月

ISSN 9784907626310

Automotive sensing is a novel and appealing sensing technology in which sensors are installed into vehicles to utilize vehicles' mobility to conduct urban sensing in smart cities. The coverage performance is a major metric to characterizing the quality-of-service of sensing systems. Despite of the coverage metrics studied in static sensor networks that consist of only spatial dimension, the lack of a proper metric to characterizing the spatio-temporal coverage of automotive sensing systems is stunting the research, development and commercialization of such mobile sensing systems. To address this issue, we propose, for the first time to the best of our knowledge, a spatio-temporal coverage metric for automotive sensing. The proposed metric characterizes the coverage in both spatial and temporal dimensions in order to provide a guideline for smart cities application developers to evaluate the quality-of-service that can be expected from an automotive sensing system. Evaluation based on an automotive sensing system implemented in Fujisawa City, Japan is conducted to demonstrate the usage of this metric in a realistic scenario.

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SpoTrip:観光客リピータ化促進のための隠れスポット情報提供システムの評価

徳田英幸片山晋, 中澤仁, 高汐一紀, , 礒川直大, 小渕幹夫, 西山勇毅, 大越匡, 米澤拓郎

電子情報通信学会技術研究報告 116 （ 508 ） 157 - 163 2017年03月

NiSleep:ゲーミフィケーションを適用可能な睡眠評価

徳田英幸江頭和輝, 古川侑紀, 西山勇毅, 大越匡, 米澤拓郎, 中澤仁, 高汐一紀

情報処理学会研究報告(Web) 2016-UBI-50 （ 2 ） 1 - 6 2016年05月

リアルタイムランキングシステムで観測されたコミュニティの共振現象

徳田英幸小島清信

情報処理学会論文誌ジャーナル(Web) 56 （ 1 ） 148 - 160 2015年01月

Wapplet:A Media Access Framework for Wearable Applications

T.Iwamoto, N.Nishio, H. Tokuda

International Conference on Information Networking （ - ） 5D4.1-5D4.11 2002年02月

研究論文（学術雑誌）, 共著, 査読有り

This paper presents a new framework for constructing applications for wearable computers. We do not consider wearable computing merely as a single self-confined system. Rather, wearable computing can be treated as a cooperative application with information surrounding a person and various devices attached to him/her. We have developed a frameworkof such wearable computing called ``Wapplet.'' Wapplet provides adaptation to the availability of devices as well as a systematic scheme of constructing applications for wearable computing. In this paper, we describe the design and implementation of Wapplet, and show its prototype system.

A Light-weight Transport Protocol for Home Networks

Yoshito Tobe,Hiroto Aida. Hideyuki Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 0 （ 0 ） 179-185 2002年01月

共著, 査読有り

Dynamic Message-path Generation for Improvised Composition of Networked Appliances Services

Jin Nakazawa, Masayuki Iwai, Hideyuki Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 145-154 2002年01月

共著, 査読有り

This paper presents a new middleware architecture for integrating heterogeneous information appliances on heterogeneous network for various users, called Virtual Network Appliance (VNA) Architecture. Instead of merely connecting appliances seen in existing approaches, VNA architecture accommodates creating a function alliance called a VNA. VNA Markup Language is our solution to define VNAs independent of specific home networks. Our middleware enables users not only to define VNAs by themselves (bottom-up integration), but also to virtually plug and play pre-defined VNAs (top-down integration).

PRONA:A Proactive Support System for Networked Appliances

IEEE International Workshop on Networked Appliances(IWNA) 145-154 2002年01月

共著, 査読有り

In this paper, we propose a proactive operational model for home appliances. Recently, users of home appliances often have difficulty in operating appliances due to their high functionality, complex interface, which have many buttons, and users’ lack of knowledge. The current operational model of home appliances is a reactive model, which it is necessary for users to notify appliances of operational information. This causes an increased burden on the user to understanding correct operational information. To cope with these issues we propose a proactive operational model. In this model, appliances acquire the operational information by themselves, and provide users with their services based on that information. Thus, our model eliminates the users’ burden on explicitly expressing requests to the appliances to access their services. It is necessary for programmers to satisfy the autonomy of obtaining information, interaction between users and system, and operation simplification. Based on this model, we have developed a middleware, called Proactive Support System for Networked Appliances (PRONA). PRONA is realized by acquiring information necessary for appliance operation and learning the users’ operational pattern. PRONA consists of three modules, which are the information acquisition module, the suggestion composition module, and the information manager module. The information acquisition module normalizes information gathered from sensors and appliances, and transmits it to the information manager module. The suggestion composition module learns the importance of related sensors when users operate the appliances. We represent the importance of related sensors as a weight, and transmit the weighted data to the information manager module. The suggestion composition module also provides the user suggestions from this weighted data. The information manager module stores this data in its database. We evaluated the use of PRONA in a proactive television application. PRONA’s quantitative evaluation criteria are its processing time, the accuracy of its suggestions for user’ action, and its learning time for the user’ operational pattern while varying the number of proactive components.

Implementation and Evaluation of Wapplet Framework

IEEE International Workshop on Networked Appliances(IWNA) 275-284 2002年01月

共著, 査読有り

It is important for application programmers and users to easily control networked appliances and devices without the need to be aware of their locations. In particular, network transparent control is essential for the ubiquitous computing environment. This is because end-users accomplish their tasks by coordinating devices that they are wearing, such as wearable computers and cellular phones, with various networked appliances, such as display devices and loud speakers. This paper presents the Wapplet framework, a new application framework that addresses this issue for the ubiquitous computing environment. To show the efficiency of the proposed Wapplet framework, we have evaluated it in terms of processing time. Requirements of the Wapplet framework are as follows: (a) support for object-migration, (b) location transparent method of invocation, and c abstraction of device specifics. Object migration is necessary for the ubiquitous computing environment because it is impractical to pre-install all applications on networked appliances. Thus, applications should be composed of multiple mobile modules. Location transparent control mechanisms like RPC (Remote Procedure Call) help application programmers in coordinating networked appliances. The framework needs to provide device independent Application Program Interfaces (APIs) that define interfaces to networked appliances, which eliminates the need to change device control programs for every appliance. In our implementation of the Wapplet framework we satisfied the above requirements using Java 1.2.2 on FreeBSD-4.2RELEASE as follows. Our object migration system (a) is realized by Java's Serialization mechanism. The system supports multi hop migration of mobile objects, which adapts to changes in available devices caused by users' movement. As for location transparent control (b), we developed a location transparent method invocation (LTMI) protocol that works like Java RMI or Sun RPC. Most conventional protocol, such as Java RMI, forces application programmers to manage the locations of mobile objects. We developed LTMI so application programmers only need to invoke the method name of the object but do not need to know the object's location (e.g. IP addresses). In addition, we provide device independent APIs to easily control and manage various kinds of networked appliances. The device control APIs classify networked appliances by media data types. There are four media types: for text, sound, image, and video. To evaluate the efficiency of LTMI, we measured the processing time of LTMI in comparison with Java RMI. As the result, we found that LTMI is more efficient than Java RMI in both local and remote method invocations.

m-P@gent: A Framework of Environment-Aware Mobile Applications for Small, Networked Appliances

Kazunori Takashio,Masakazu Mori, Hideyuki Tokuda

IEEE International Workshop on Networked Appliances(IWNA) 257-266 2002年01月

共著, 査読有り

Mobile agent software architecture has attracted a great deal of attention as a basic technology for building such a ubiquitous computing environment. In our framework, a mobile agent is divided into two parts: a core component and a set of add-on functional modules. Each runtime system dynamically collects add-on modules necessary for a new environment, and links them with the core component. This feature allows us to describe an application as seamless against changes of computing environment. For example, we can realize the following application behavior. When the user changed his location, his applications also move to a device that he personalized as though they followed him. Then, they adapt their contexts to the new location and continue to carry out their tasks. On a device that has a small LCD, an application can indicate its progress to a user progress. On another device that has an input interface such as a touch-panel, the application may wait for instructions from the user. We implemented mobile agent systems based on this framework on actual PCs and small, networked devices. Especially, one of the m-P@gent runtime environments, @TINI, designed for the TINI devices provides X-10 protocol libraries. An ‘agent @TINI’ can control appliances connected over X-10 network by using X-10 commands.

Detection of Congestion Signals from Relative One-Way Delay

Yoshito Tobe,Hiroto Aida, Yosuke Tamura, Hideyuki Tokuda

情報処理学会論文誌 42 （ 12 ） 3222-3230 2001年12月

共著, 査読有り

OR2: A Path Tuning Algorithm for Routing in Ad Hoc Networks

Masato Saito,Hiroto Aida, Yoshito Tobe, Yosuke Tamura, Hideyuki Tokuda

IEEE LCN Workshop on Wireless Local Networks (WLN '01) 560-567 2001年11月

共著, 査読有り

This paper presents 'OR2'', an adaptive path tuning scheme for mobile ad hoc networks. In OR2, the active path adapts dynamically to node mobility without any link failures based on the local link quality. Most conventional routing protocols accommodate the change of network topology only when the link fails. Unless the movement of intermediate nodes leads to any link failures, they cannot adapt to the network topology even if other routes with less hop count become available. In contrast to these protocols, OR2 reduces the hop count of an active route while data packets are sent without link disconnection. Specifically, by introducing the notion of proximity that indicates the nearness of two communicating nodes, OR2 skips the upstream node in a proximity area and continues to shorten an active route as possible. For delay sensitive TCP flows, reducing the number of hops and path delay significantly improves the performance of TCP. We have implemented OR2 as an extension to DSR on FreeBSD. The experimental results have shown that OR2 is effective in enhancing TCP throughput and reducing end-to-end delay for all relevant flows.

m-P@gent: A Framework for Describing Environment-Aware Mobile Agents on Ubiquitous Computing Environment

Kazunori Takashio,Masakazu Mori, Hideyuki Tokuda

IEEE International Conference on Ubiquitous Computing (Ubicomp 2001), Workshop on Application Models and Programming Tools for Ubiquitous Computing (UbiTools 2001) 2001年09月

共著, 査読有り

This paper proposes a new framework m-P@gent for environment-aware mobile agents that can run even on resource-limited devices and appliances. In the framework, a mobile agent is divided into a two parts: a core and addon functional modules. Each runtime system dynamically collects add-on modules necessary for a new environment, and links them with the core component. This feature allows us to describe an application seamless against changes of computing environment. We implements mobile agent systems based on the framework on actual PC environments and small PDA devices, and evaluates their basic performance. Our system makes two contributions. One is that it shows a possibility for expanding the field of mobile agent to resource-limited devices. Another is it reduces the cost of an agent migration. The framework will be a core software infrastructure for building ubiquitous computing environment.

Flexible Distributed Event-Driven Programming Framework for Networked Appliances and Sensors

3rd International Symposium on Distributed Objects and Applications (DOA01) (Short Papers Proceed) 61-68 2001年09月

共著, 査読有り

This paper presents a new framework for constructing flexible event-driven systems for distributed networked devices and appliances, referred to as Dragon. Dragon enables constructing and modifying an event-driven system easily by visualizing distributed services which are handled in an integrated manner. The update of the system is conducted immediately following a modification by Dragon. Dragon is built on Jini/Java and can be executed on any Jini/Java-compliant machines. In addition, Dragon incorporates soft real-time event delivery to enhance the predictability of behavior of the constructed system and composition of distributed services for event management.In this paper, we describe the details of design and implementation of Dragon.

On Dynamic Service Integration in VNA Architecture

Jin Nakazawa,Yoshito Tobe, Hideyuki Tokuda

電子情報通信学会論文誌（電子情報通信学会論文誌多次元移動情報ネットワーク特集号） E84-A （ 7 ） 1610-1623 2001年07月

研究論文（学術雑誌）, 共著, 査読有り

In forthcoming home network environment, computation capability will be embedded invisibly in home appliances, sensors, walls, ceilings, and floors. People will conduct various tasks using multiple devices simultaneously without consciousness of using computers. In this paper, first, we propose an application model named Virtual Network Appliance (VNA) model which simplify and expand device utilization. In the model, each device has VNA runtime system and function objects, called VNA components, running on it. A user task is defined in an application called VNA which is a logical appliance consisting of abstract function requirements and a message graph among them. Second, we propose Virtual Plug&Play mechanism which is a dynamic service integration mechanism in VNA model implementation. When a user conducts a task, he/she makes a VNA runtime system on a user-side terminal load a VNA definition appropriate for the task. Virtual Plug&Play dynamically discovers required VNA components and establishes the message graph as defined. Since XML documents are used to describe a VNA, users can share and customize it easily. We call the device integration done by Virtual Plug&Play top-down integration, which existing middleware do not aim at. Finally, we show that Virtual Plug&Play affords practical performance for top-down integration by performance evaluation.

A Software Approach to Channel-State Dependent Scheduling for Wireless LANs

Hiroto Aida,Yoshito Tobe, Masato Saito, Hideyuki Tokuda

The 4th ACM International Workshop on Wireless Mobile Multimedia (WOWMOM 2001) 34-43 2001年07月

共著, 査読有り

This paper proposes a new practical packet scheduling scheme for wireless LANs called SoCPS and also explores extensively the effectiveness of wireless packet scheduling under a variety of conditions over an actual wireless LAN. One well-known aspect in packet scheduling at the base station is consideration of channel state dependency. In conventional studies, the channel state is expressed in microscopic two states in the Markovian sense. To eliminate a large overhead associated with acquiring such a fine-grain channel state and to establish a software-based enhancement, we introduce the notion of Strength of Connection (SoC) which can be expressed as the long-term strength of the connectivity between the base station and an end host. We examine schemes for identifying the channel state and examine the applicability to packet scheduling. We also design a packet scheduling scheme based on SoC called SoCPS. Finally, we investigate the performance under various conditions of traffic and wireless channel states. We have designed and implemented SoCPS on FreeBSD computers. Our evaluation results obtained with up to eight wireless-LAN nodes have determined the applicability of SoCPS and limitation in wireless packet scheduling for wireless LANs. In particular, while FIFO is sufficient in many cases where TCP traffic is dominant, scheduling with SoC consideration is effective for real-time UDP traffic.

IP Fragment情報を利用したルータにおける効率的なパケット破棄手法

田村陽介,戸辺義人，徳田英幸

情報処理学会論文誌 42 （ 6 ） 1483-1491 2001年06月

共著, 査読有り

IP層において上位アプリケーションのフレームを考慮するApplication Level Framingは長年の課題である．ルータがIPヘッダ以外の情報をもとにパケットを制御することはスケーラビリティの点で不利である．また同時にルータのパケット中継の作業を複雑にしてしまう恐れがある．本論文で我々は送信ホストはIP Fragmentを積極的に活用することにより，ルータに対してアプリケーションデータの境界線を知らせるべきであると主張する．我々が提案するTransport framE Discard（TED）はルータがパケットを破棄する際に，このIP Fragmentの情報を用いてパケットを破棄する順序を動的に変更させる．TEDを利用することでルータはアプリケーションデータの単位でパケットを破棄することが可能となる．我々はTEDをFIFO，WFQ，RED，Random Drop FIFOに組み合わせて実装し，評価した．その結果，ネットワーク内における全体のパケット欠損率を変化させずに，無駄なパケットの中継を回避し，上位アプリケーションに対して高い通信性能を実現することが実証された．

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