Tenshi Hara

Decentralised approach for a reusable crowdsourcing platform utilising standard web servers

Crowdsourcing has gained increasing interest during the last years as means for solving complex tasks with the help of a flexible group of contributors. The crowd can contribute with collecting data in the field, completing map information or votes for ideas or products. Even though the participation of large numbers of users with heterogeneous devices in crowdsourcing is a highly recurrent task, generic infrastructures for crowdsourcing can be hardly found. Especially the management of users, mobile devices and contributed data has to be repetitively implemented in new projects. To ease the development of crowdsourcing applications, in this paper we propose a generic platform for crowdsourcing supporting diverse crowdsourcing scenarios, the ability to handle large numbers of users and the involvement of heterogeneous mobile devices. The evaluation is based on scalability and performance experiments in order to demonstrate the feasibility of our approach.

Comparing Tool-supported Lecture Readings and Exercise Tutorials in Classic University Settings

Teaching in classic courses offers too little interaction between docents and students and should be improved. Addressed approaches include a range from Simple Voting Systems to Clickers and Audience Response Systems, and interaction and Student motivation may be improved therein. However, different university course settings are affected in different ways by these systems. Therefore, this paper presents a comparison of a selected range of these systems (implemented as tool kits) within two course settings, namely lecture readings and exercise tutorials. These tools are Audience Response Systems, Question and Answer Systems (Q&A Systems), Discussion Systems (Panels), as well as Virtual Whiteboard Feedback Systems. A synopsis of feasibility for different settings is provided and concluded with important results on the distinguishability of Q&A Systems and Panels.

Towards a Reusable Infrastructure for Crowdsourcing

In the course of the last few years crowd sourcing has received growing research focus due to its conception of solving complex tasks with the help of a flexible group of contributors of whom each needs to only contribute a simpler task part. Hence, the crowd can contribute by collecting data from distributed locations, completing map information, or voting on product ideas, et cetera. However, even though it is a necessary conceptual feature, the participation of large numbers of users with heterogeneous devices, generic infrastructures for crowd sourcing can hardly be found. For example, the management of users, mobile devices and contributed data has to be repetitively implemented in new projects. To ease the development of crowd sourcing applications, in this paper we propose a generic platform for simplified crowd sourcing deployment while supporting diverse crowd sourcing scenarios, the ability to handle large numbers of users and the involvement of heterogeneous mobile devices. The focus therein is put on the deployment process. Hence, the evaluation is based on an actual deployment, namely the migration of Cyface, an existing crowd sourcing project build from scratch, into using our proposed infrastructure.

ML-SLA: Multi-Level Service Level Agreements for Highly Flexible IoT Services

Service systems in upcoming application domains like the Internet of Things (IoT) have a high demand for dynamic changes of provided service quality and related pricing. Changes can be requested by service consumers to address adjusted requirements at application level or by service providers to accommodate resource constraints. Anyway, traditional approaches to handle Service Level Agreements (SLA) are limited to a predefined service quality provided for a fixed price. Changed application requirements or SLA violations result in a re-negotiation, usually combined with a service termination. In this paper we present a novel approach called Multi-Level SLA (ML-SLA) that supports the negotiation of multiple service levels combined with an extended service runtime environment. It supports dynamic level switches during the execution phase of an SLA initiated by service consumers or providers. An evaluation based on the implementation of the Multi-Level SLA concept demonstrates that quality levels of services can be efficiently changed without service termination.

An integrated system for indoor and outdoor location-based services (MapBiquitous): mobisys'13 poster abstract

Within the last decade, outdoor location services have developed to be ubiquitous and generally available to the majority of users, be it on desktop pcs or on mobile devices such as smartphones and tablets. However, these types of services are limited to outdoor areas, e.g. navigation between two buildings. The logical next step was to expand to the indoor area, for which recently different indoor location services, especially navigation services, have emerged. Up to now, these solutions lack global coverage, since most of them operate in a proprietary and isolated manner. This fact makes the integration of outdoor and indoor location based systems a very topical area of research. Major challenges are the provisioning of building information in an interoperable and scalable manner, the support of heterogeneous technologies (e.g. based on various technologies like Wifi, RFID, or smartphone sensors) for indoor positioning and the cross-building navigation with pathes inside and outside buildings. MapBiquitous∗ addresses these challenges by providing an integrated system for indoor and outdoor locationbased services. The basic principle envisages a decentralised client/server architecture with building servers providing the necessary building information, e.g. ichnography, floor plans and navigation information. Clients are able to discover building servers using a location-based directory service and load building information at the granularity of floor plans with separate layers for navigation and positioning. To ensure interoperability of building information, open standards for accessing and representing building information are used. We particularly use the Web Feature Service (WfS) and the Geography Markup Language (GML) specified by the Open Geospatial Consortium (OGC). Floor plans contain geometric information representing rooms and floors as polygons as well as semantic information like room numbers and room descriptions. Clients store that information in a local model and project floor plans onto the map information based on overlays. Since WGS 84 coordinates are used, no coordinate transformation is required to match positions provided by GPS. To determine the position we support multiple positioning methods. In addition to GPS two modes are supported: On the one hand, multilateration based on WLAN access ∗ Project description and comprehensive list of references at http://goo.gl/eqJkG Copyright is held by the author/owner(s). MobiSys’13, June 25–28, 2013, Taipei, Taiwan. ACM 978-1-4503-1672-9/13/06. Functional showcase architecture of MapBiquitous points can be utilised. On the other hand, building servers can provide a service for positioning based on WiFi fingerprints. Furthermore, mobile device sensors (particularly magnetometer, accelerometers and barometer) are used to determine orientation and distance of relative movements as well as the floor level. The concept for calculating navigation paths is based on the shortest path algorithm by Dijkstra. The calculation is carried out by the involved building servers. For outdoor paths Google Maps Navigation API is used. Ascertainment and correction of information is supported by a distributed crowdsourcing architecture that makes users and their submissions anonymous towards the building servers while maintaining retroactive cancellation of submissions as well as anonymous user ratings. Building servers are implemented based on GeoServer and WfS. An Android App serves as MapBiquitous client. Crowdsourcing is ought to be a self-organising P2P network. Our research includes feasible methods of positioning by smartphones, combination of different approaches (e.g. angulation with pace models) as well as possibilities of correcting data and ascertainment of real time information. The focus remains on mobile computing and offline availability.

On Providing Crowdsourcing as a Service

In this paper we present an approach to separate submission capturing and processing from basic crowd sourcing functionality to create reusable crowd sourcing services which are more flexible and secure.

Graphicuss - Temporal Visualisation of Canvas Creation Processes.

The use of graphical models to describe complex topics is very common in teaching, helping students build an adequate model of knowledge presented. Often, students discuss open questions on-line in forums. Backtracking of errors conducted during the creation process is hard. The individual steps of developing a solution – the temporal information – are lost. Graphicuss combines concepts of textual discussion systems and graphical feedback systems. It fosters better discussions and comprehension through access to the temporal information of canvases. Especially self-regulated learning benefits from the addition of temporal information; students’ skill acquisition capabilities are amplified. Yet, an intuitive representation of temporal information is still required. Based on image and video processing, we investigated existing metaphors for temporal information. A series of user studies emphasises the differences of the metaphors in varying use-cases and strongly points at a candidate suitable and feasible for PCs as well as mobile devices.

Multi-level De-anonymisation for Initially Anonymous Discussion Systems in a Self-regulated Learning Environment.

Discussion systems are a valuable asset in attaining self-regulated learning. Beyond the limitations of oncampus classroom settings, they enable internal feedback, peer feedback as well as external feedback. A motivating factor to continued and frequent utilisation of such systems is anonymity. However, anonymity is a double-edged sword. On one side, it provides strong incentives to use discussion systems, on the other side it invites destructive behaviour such as trolling. Furthermore, strong students are discouraged from continued utilisation if they cannot attribute their contribution to themselves. We propose an initially anonymous discussion system, which enables retroactive de-anonymisation on multiple levels, namely with respect to the identity degree as well as the attribution dimension.

Graphicuss - Proposing a Graphical Discussion System.

In this position paper, we present an approach to a graphical discussion tool, namely Graphicuss. It combines known concepts of textual discussion systems (such as forums) and graphical feedback systems (such as virtual interactive whiteboards) into a single canvas-based application. Graphicuss aims at graphics-based or -enhanced discussions within a classroom setting. The goal is to allow all students to participate in such discussions, rather than only a selected few students at a physical blackboard/whiteboard presenting their work as a discussion base. The combination of text and graphics allows for better discussion of concepts through temporal correlation of text and graphics. Thus, Graphicuss applies known text-based discussion features (such as quoting) to the graphical level while adding temporal context. Rather than quoting/forwarding an invariable or only amendable image, Graphicuss enables quoting up until any point in time with changes/amendments thereafter. After presenting the conceptual ideas and a few comments on our prototype, we discuss a some preliminary findings with respect to interface design as well as storage requirements.

A Concept for Interoperable IoT Intercloud Architectures.

Cloud platforms have evolved over the last years as means to provide value-added services for Internet of Things (IoT) infrastructures, particularly smart home applications. From different use cases the necessity arises to connect IoT cloud solutions of different vendors. While some established platforms support an integration of other vendors’ systems into their own infrastructure, solutions to federate IoT cloud platforms can hardly be found. In this paper, we analyze existing IoT cloud platforms with respect to their similarities and derive a concept of an Intercloud Broker (IB) that enables the establishment of an IoT Intercloud to support interoperability of cloud-based IoT platforms from different vendors. To demonstrate the feasibility of our approach we evaluated the overhead introduced by the Intercloud Broker. As the results show, the IB can be implemented with minimal overhead in terms of throughput and delay even on commodity hardware.