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The objective of this thesis is to implement a computer game based motivation system for maximal strength testing on the Biodex System 3 Isokinetic Dynamometer. The prototype game has been designed to improve the peak torque produced in an isometric knee extensor strength test. An extensive analysis is performed on a torque data set from a previous study. The torque responses for five second long maximal voluntary contractions of the knee extensor are analyzed to understand torque response characteristics of different subjects. The parameters identifed in the data analysis are used in the implementation of the 'Shark and School of Fish' game. The behavior of the game for different torque responses is analyzed on a different torque data set from the previous study. The evaluation shows that the game rewards and motivates continuously over a repetition to reach the peak torque value. The evaluation also shows that the game rewards the user more if he overcomes a baseline torque value within the first second and then gradually increase the torque to reach peak torque.
In the eld of accessing and visualization mobile sensors and their recorded data, di erent approaches were realized. The OGC1 Sensor observation Service supplies a standard to access these information, stored on servers. To be able to access these servers, an interface must be developed and implemented. The result should be a con gurable development framework for web-based GIS clients supporting the OGC sensor observation services. In particular the framework should allow continuous position updates of mobile sensors. Visualization features like charts, bounding boxes of sensors and data series should be included.
This work extends the affordance-inspired robot control architecture introduced in the MACS project [35] and especially its approach to integrate symbolic planning systems given in [24] by providing methods to automated abstraction of affordances to high-level operators. It discusses how symbolic planning instances can be generated automatically based on these operators and introduces an instantiation method to execute the resulting plans. Preconditions and effects of agent behaviour are learned and represented in Gärdenfors conceptual spaces framework. Its notion of similarity is used to group behaviours to abstract operators based on the affordance-inspired, function-centred view on the environment. Ways on how the capabilities of conceptual spaces to map subsymbolic to symbolic representations to generate PDDL planning domains including affordance-based operators are discussed. During plan execution, affordance-based operators are instantiated by agent behaviour based on the situation directly before its execution. The current situation is compared to past ones and the behaviour that has been most successful in the past is applied. Execution failures can be repaired by action substitution. The concept of using contexts to dynamically change dimension salience as introduced by Gärdenfors is realized by using techniques from the field of feature selection. The approach is evaluated using a 3D simulation environment and implementations of several object manipulation behaviours.
The task of this thesis is to develop an OGC-compliant Sensor Observation Service (SOS) { a component of the SWE { for GPS related sensor data in this context. It should, in contrast to existing implementations, support full mobility of the sensors and be con gurable with respect to adding di erent kinds of sensors. In particular, mobile phones should be considered as sensors, which transmit their data to the SOS server through the transactional SOS interface.
This report presents an approach on a quadrotor dynamics stabilization based on ICP SLAM. Because the quadrotor lacks sensory information to detect its horizontal drift an additional sensor as Hokuyo-UTM has been used to perform on-line ICP-based SLAM. The obtained position estimates were used in control loops to maintain desired position and orientation of the vehicle. Such attitude parameters as height, yaw and position in space were controlled based on the laser data. As a result the quadrotor demonstrated two significant for autonomous navigation capabilities: performance of on-line SLAMon a flying vehicle and maintaining desired position in 3D space. Visual approach on optical flow based on Pyramid Lucas-Kanade algorithm has been touched and tested in different environmental conditions though hasn't been implemented in the control loop. Also the performance of the Hokuyo laser scanner and the related to it ICP SLAM algorithm have been tested in different environmental conditions indoors, outdoors and in presence of smoke. Results are presented and discussed. The requirement of performing on-line SLAM algorithm and to carry quite heavy equipment for it forced to seek a solution to increase the payload of the quadrotor with its computational power. A new hardware and distributed software architectures are therefore presented in the report.
Distributed systems comprise distributed computing systems, distributed information systems, and distributed pervasive systems. They are often very complex and their implementation is challenging. Intensive and continuous testing is indispensable to ensure reliability and high quality of a distributed system. The testing process should have a high degree of automation, not only on lower levels (i.e. unit and module testing), but also on higher testing levels (e.g. system, integration, and acceptance tests). To achieve automation on higher testing levels virtual infrastructure components (e.g. virtual machines, virtual networks) that are offered as a Service (IaaS) can be employed. The elasticity of on-demand computation resources fits well together with the varying resource demands of automated test execution.
A methodology for automated acceptance testing of distributed systems that uses virtual infrastructure is presented. It is founded on a task-oriented model that is used to abstract concurrency and asynchronous, remote communication in distributed systems. The model is used as groundwork for a domain-specific language that allows expressing tests for distributed systems in the form of scenarios. On the one hand, test scenarios are executable and, therefore, fully automated. On the other hand, test scenarios represent requirements to the system under test making an automated, example-based verification possible.
A prototypical implementation is used to apply the developed methodology in the context of two different case studies. The first case study uses RCE as an example of a distributed, workflow-driven integration environment for scientific computing. The second one uses MongoDB as an example of a document-oriented database system that offers distributed data storage through master-slave replication. The results of the experimental evaluation indicate that the developed acceptance testing methodology is a useful approach to design, build, and execute tests for distributed systems with high quality and a high degree of automation.
This work aims to create a natural language generation (NLG) base for further development of systems for automatic examination questions generation and automatic summarization in Hochschule Bonn-Rhein-Sieg and Fraunhofer IAIS, respectively. Nowadays both tasks are very relevant. The first can significantly simplify the university teachers' work and the second to be of assistance for a faster retrieval of knowledge from an excessively large amount of information that people often work with. We focus on the search for an efficient and robust approach to the controlled NLG problem. Therefore, though the initial idea of the project was the usage of the generative adversarial neural networks (GANs), we switched our attention to more robust and easily-controllable autoencoders. Thus, in this work we implement an autoencoder for unsupervised discovery of latent space representations of text, and show the ability of the system to generate new sentences based on this latent space. Apart from that, we apply Gaussian mixture techniques in order to obtain meaningful text clusters and thereby try to create a tool that would allow us to generate sentences relevant to the semantics of the Gaussian clusters, e.g. positive or negative reviews or examination questions on certain topic. The developed system is tested on several datasets and compared to GANs' performance.
Object detection concerns the classification and localization of objects in an image. To cope with changes in the environment, such as when new classes are added or a new domain is encountered, the detector needs to update itself with the new information while retaining knowledge learned in the past. Previous works have shown that training the detector solely on new data would produce a severe "forgetting" effect, in which the performance on past tasks deteriorates through each new learning phase. However, in many cases, storing and accessing past data is not possible due to privacy concerns or storage constraints. This project aims to investigate promising continual learning strategies for object detection without storing and accessing past training images and labels. We show that by utilizing the pseudo-background trick to deal with missing labels, and knowledge distillation to deal with missing data, the forgetting effect can be significantly reduced in both class-incremental and domain-incremental scenarios. Furthermore, an integration of a small latent replay buffer can result in a positive backward transfer, indicating the enhancement of past knowledge when new knowledge is learned.
Grid services will form the base for future computational Grids. Web Services, have been extended to build Grid services. Grid Services are dened in the Open Grid Service Architecture (OGSA). The Globus Alliance has released a Web Service Resource Framework, which is still under development and which is still missing vital parts. One of them is a Concept that allows Grid-Service Requests to securely traverse Firewalls, and its realization. This Thesis aims at the development and realization of a detailed Concept for an Application Level Gateway for Grid services, based on an existing rough concept. This approach should enable a strict division between a local network and the Internet. The internet is considered as a untrusted site and the local network is considered as a trusted site. Grid resources are placed in the internet as well as in the local network. This means that the possibility to communicate through a Firewall is essential. Some further protocols like Grid Resource Allocation and Management (GRAM) and the Grid File Transfer Protocol (GridFTP) must be able to traverse the network borders securely as well, while no further actions must be taken from the user side. The German Federal Oce for Information Security (BSI) proposes a Firewall - Application Level Gateway (ALG) - Firewall solution to the German Aerospace Center (DLR) where this Thesis is written, as a principle approach. In this approach, the local network is divided from the Internet with two rewalls. Between those rewalls is a demilitarized zone (DMZ), where computers may be placed, which can be accessed from the Internet and from the local network. An ALG which is placed in this DMZ should represent the local Grid nodes to the Internet and it should act as a client to the local nodes. All Grid service requests must be directed to the ALG instead of the protected Grid nodes. The ALG then checks and validates the requests on the application level (OSI layer 7). Requests that pose no security threat and fulll certain criteria will then be forwarded to the local Grid nodes. The responses from the local Grid nodes are checked and validated by the ALG as well.
Distributed computing environments allow collaborative problem solving across teams and organisations. A fundamental precondition for collaboration is the ability to find available participants and be able to exchange information. One way to approach this conceptual formulation are central directories or registry services. A major disadvantage of centralized components is, that they limit the flexibility to form ad hoc networks that are targeted to solve a specific problem. To facilitate flexible and dynamic collaborations, ideas from decentralized and self-organising networks can be combined with concepts of service oriented computing. This project aims to investigate potential solutions for dynamic discovery of network participants and outlines how to manage challenges associated with the development of a discovery protocol for distributed systems. During the course of this project a prototypical implementation was created that integrates into the open source distributed, collaborative problem solving environment RCE [9]. It is currently developed at the German Aerospace Center (DLR) but is planned to make the framework available to broader community.