Vol.12 No.1&2 April 8, 2016

A Flexible Router with Tangible Network Interfaces for Sharing a Last Mile and its Performance (1-16)
        Toshikazu Nishimura
After the big earthquake in 2011 in Japan, the disaster survivors lost the means to acquire and convey information in the stricken area. In this paper, we propose a means to share seamless access to the Internet immediately among survivors using surviving access lines including ground infrastructures and satellite communications even if disaster exceeds assumption. We introduce the notion of TNI (Tangible Network Interface) that can easily configure small handy router named Flexible Router on site without configuring the settings of router from external console device. We also introduce Integrated Wireless Authentication System to share Internet access line among disaster survivors. We implemented Flexible Router and its TNIs and demonstrate its performance as well as the solution to improve its poor performance of Wi-Fi device and the intercontinental throughput measurement over VPN (Virtual Private Network).

A Scheduling Method for Waiting Time Reduction in Area-based Broadcasting Considering Loading Time (17-30)
        Yusuke Gotoh and Tomoki Yoshihisa
Due to the recent popularization of digital broadcasting systems, clients can watch several types of contents. In addition, area-based broadcasting, which uses the bandwidth that is not used in radio broadcasting, has attracted great attention. In area-based network environments, a server can deliver continuous media data such as audio and video in a limited area. Clients can get improved convenience by receiving such information as shopping coupons and community news based on their watching area using their own nodes. In area-based broadcasting, many clients watch content in the delivery area. Although servers can concurrently deliver data to many clients, they have to wait until their data are broadcast. To reduce waiting times, many studies employ the division-based broadcasting technique, which reduce waiting times by dividing the data into several segments and frequently broadcasting the precedent segments. These scheduling methods make a broadcast schedule that considers the situation in actual network environments. When the server makes a broadcast schedule in area-based broadcasting, it needs to consider both the loading times of the highlight and main scenes. In broadcasting, since the playing time of the commercial contents is predetermined, clients watch them during the loading time. Therefore, the server needs to make the broadcast schedule based on the consumption rate and the number of channels by setting both the loading times of the highlight and main scenes. In this paper, we propose a scheduling method that considers the loading time for area-based broadcasting. In our scheduling method, since the server makes a broadcast schedule using a different ratio of dividing the data for highlight and main scenes, the waiting time is reduced effectively.

CoreASM-Based Evaluation of the N-AODV Protocol for MANETs (31-51)
        Alessandro Bianchi, Sebastiano Pizzutilo, and Gennaro Vessio
Network topology awareness (NTA) is a fundamental issue in the context of computer networks: the lack of control over the topology can negatively impact performance, security, resilience, and so on. However, in Mobile Ad-hoc NETworks (MANETs), NTA is difficult to achieve because of their dynamicity. Different reactive protocols for MANETs, in which routes are established only when needed, provide different NTA to each host, depending on their algorithmic features. NACK-based AODV (N-AODV) is a variant of the well-known Ad-hoc On-demand Distance Vector (AODV) reactive protocol for MANETs which we proposed with the aim of improving the NTA of the original protocol. In this paper, an experiment aimed at comparing N-AODV to AODV is reported; it moves from an exploratory case study we conducted preliminarily. The results obtained show that a MANET adopting N-AODV exploits higher NTA than a MANET adopting AODV. Moreover, the improved awareness positively impacts effectiveness.

YOUPLAY: Designing Participatory Theatrical Performance using Wearable Sensors (52-75)
        Naoya Isoyama, Masahiro Kinoshita, Ryo Izuta, Tsutomu Terada, and Masahiko Tsukamoto
This paper describes a participatory theatrical performance named YOUPLAY. In YOUPLAY, a general person who is usually treated as an audience member becomes an actor and plays a character role in the performance. He/she wears several types of equipments such as sensors and a microphone, and experiences an interactive story. While our system presents various interactive stage effects using wearable sensors, these devices raise hardware/software troubles. We found during the development and actual use of the system that such interactive systems need robust activity recognition techniques. We explain the details of the system for YOUPLAY and present the knowledge gathered from 80 actual stages. Additionally, we discuss the general design for interactive system with the results of questionnaires that are gathered from participants of our system, the occurrence of the troubles, and the way to deal with them.

Is Bluetooth Low Energy an Alternative to Near Field Communication (76-90)
        Wolfgang Narzt, Lukas Furtmuller, and Matthisa Rosenthaler
While the Bluetooth Low Energy (BLE) standard is commonly being used for energy-efficient mid-range data transmission and localization where distances of several meters are to be covered, its signal characteristics also reveals stable and deterministic behavior in the ultra-short range with significant higher signal strengths compared to distant placements, which potentially qualifies BLE as a substitute technology for Near Field Communication (NFC) for the purpose of identifying objects at very short distances. This paper investigates the signal strength behavior of BLE at a few centimeters distance between transmitter and receiver, points out strengths and weaknesses in terms of antenna alignments, shielding issues and interfering signals and presents potential application areas for ultra-short range object identification with a transmission technology that is not designed for that purpose.

Multi-Platform Mobile Service Creation: Increasing Brand Touch-Points for Hotels (91-109)
        Elias Kärle and Anna Fensel
With the introduction of smart phones, the marketing possibilities for businesses changed fundamentally. New advertisement and publication mechanisms developed a new way of communication between business and customers in a more frequent and more personalized way. This paper describes a design approach for the development and implementation of a tool which can be used by hotels as well as by other end-user oriented businesses to keep close contact with customers by using a technology almost everyone uses nowadays -- the smart phone. Offering a possibility for the customers to communicate with the business is as important as leaving the business' imprint on the customer and keeping the customer's retention by increasing brand touch points. To accomplish the above mentioned requirements we propose the design and implementation of a content management system (CMS) rendering mobile apps for different platforms: Android, iOS and in mobile website mode. After the roll out of the resulting product and a testing phase with two customers it is apparent that the utilization of mobile marketing mechanisms really increases the brand touch points and has a high acceptance rate by customers of all ages, genders and social environments.

Clustering and Nearest Neighbour Based Classification Approach for Mobile Activity Recognition (110-124)
        Sulaimon Bashir, Daniel Doolan, and Andrei Petrovski
We present a hybridized algorithm based on clustering and nearest neighbour classifier for mobile activity recognition. The algorithm transforms a training dataset into a more compact and reduced representative set that lessens the computational cost on mobile devices. This is achieved by applying clustering on the original dataset with the concept of percentage data retention to direct the operation. After clustering, we extract three reduced and transformed representation of the original dataset to serve as the reference data for nearest neighbour classification. These reduced representative sets can be used for classifying new instances using the nearest neighbour algorithm step on the mobile phone. Experimental evaluation of our proposed approach using real mobile activity recognition dataset shows improved result over the basic KNN algorithm that uses all the training dataset.

Structured-light-based Depth Reconstruction Using Low-light Pico Projector (125-137)
        Thomas Rittler, Florian Seitner, and Margrit Gelautz
In this work we investigate an infrared structured light prototype which is intended for 3D reconstruction in resource-restricted mobile applications. We explore the constraints on working range and pattern resolution that are imposed by the low-light property of our single-shot set-up. While focusing on the most light-sensitive steps of the decoding workflow, we suggest adaptations of image rectification, pattern generation and segmentation algorithms that are tailored to the specific spatial and radiometric requirements of our system. We incorporate two disparity estimation techniques based on codeword look-up and foreground/background segmentation into our system and analyze the effects of different algorithmic components on the overall runtime of our implementation.

Rapid Prototyping of a Mobile SAAS Application (138-158)
        A Alamaki, A Dirin, J Huotari, and N Korhonen
Rapidly developing a customizable mobile application and the related software as a service (SaaS) is challenging and rarely studied. Traditionally, SaaS solutions are mainly accessed using personal computers, but the mobile SaaS solutions are needed in the tourism sector, for example, where users are mobile. This paper presents a case study where the original need was to design a customizable mobile tourism guide service for use by several small tourism companies, and to assess its functionality in a field study. The result of applying the Vaadin 6 Java web framework and LAMP technologies was a robust mobile application SaaS prototype system that fulfilled the essential design needs in the eight field test cases. This study shows that the field testing of a mobile concept can be completed easier when using Vaadin Java web framework, as it provides support for cross-platform functionality and GUI design, and completes, for example, LAMP-based SaaS solution. However, results point it out that new digital navigation features were needed to develop or improved and mobile web approach causes some usability challenges especially in the compass based navigation and user tracking. This study provides an example of how to develop a SaaS-based mobile service prototyping environment, which is needed while field testing new B2B mobile services with various groups of stakeholders. Our case study analysis reveal that the Vaadin development environment facilitates the rapid prototyping for digital services in an affordable way. The overall contribution of this paper is predominantly for software engineers and web application developers.

Privacy-Based Adaptive Context-Aware Authentication System for Personal Mobile Devices (159-180)
        Zhan Liu, Riccardo Bonazzi, and Yves Pigneur
Over the past decade, mobile devices such as smartphones have become increasingly common as a form of handheld computing platform. The use of mobile applications on these mobile devices is experiencing unprecedented rates of growth. However, when using mobile applications, users are often requested to give context information. Such requests have led to growing privacy concerns. This paper proposes the use of context-awareness to improve single sign-on (SSO) solutions so that mobile users can protect their private information. A privacy-based adaptive SSO (ASSO) may be able to increase users’ perceived ease of use of the system and give service providers the necessary authentication security for their applications. The study was based on data gathered from 168 participants as part of the Lausanne Data Collection Campaign. This was led by the Nokia research center in Switzerland and used Nokia N95 phones. The analysis of SVM showed our expectations to be correct. Consequently, a new business model for mobile platforms has been proposed to reinforce our claim that privacy-friendly value propositions are possible and can be used to obtain a competitive advantage.

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