Multi-Quality Auto-Tuning by Contract Negotiation

A characteristic challenge of software development is the management of omnipresent change. Classically, this constant change is driven by customers changing their requirements. The wish to optimally leverage available resources opens another source of change: the software systems environment. Software is tailored to specific platforms (e.g., hardware architectures) resulting in many variants of the same software optimized for different environments. If the environment changes, a different variant is to be used, i.e., the system has to reconfigure to the variant optimized for the arisen situation. The automation of such adjustments is subject to the research community of self-adaptive systems. The basic principle is a control loop, as known from control theory. The system (and environment) is continuously monitored, the collected data is analyzed and decisions for or against a reconfiguration are computed and realized. Central problems in this field, which are addressed in this thesis, are the management of interdependencies between non-functional properties of the system, the handling of multiple criteria subject to decision making and the scalability. In this thesis, a novel approach to self-adaptive software--Multi-Quality Auto-Tuning (MQuAT)--is presented, which provides design and operation principles for software systems which automatically provide the best possible utility to the user while producing the least possible cost. For this purpose, a component model has been developed, enabling the software developer to design and implement self-optimizing software systems in a model-driven way. This component model allows for the specification of the structure as well as the behavior of the system and is capable of covering the runtime state of the system. The notion of quality contracts is utilized to cover the non-functional behavior and, especially, the dependencies between non-functional properties of the system. At runtime the component model covers the runtime state of the system. This runtime model is used in combination with the contracts to generate optimization problems in different formalisms (Integer Linear Programming (ILP), Pseudo-Boolean Optimization (PBO), Ant Colony Optimization (ACO) and Multi-Objective Integer Linear Programming (MOILP)). Standard solvers are applied to derive solutions to these problems, which represent reconfiguration decisions, if the identified configuration differs from the current. Each approach is empirically evaluated in terms of its scalability showing the feasibility of all approaches, except for ACO, the superiority of ILP over PBO and the limits of all approaches: 100 component types for ILP, 30 for PBO, 10 for ACO and 30 for 2-objective MOILP. In presence of more than two objective functions the MOILP approach is shown to be infeasible

Quantitative wavelength-resolved fluorescence detection for microchip capillary electrophoresis

This thesis describes the development and application of a new wavelengthresolved CCD-based fluorescence detector for microchip separations. In recent years, miniaturization has been one of the major trends in the development of new analytical separation systems. As the manipulated sample amounts and detection volumes on microchips have become smaller and smaller, the need for high-performance detection systems has never been more relevant. Applied methods of detection have to be well adapted to the small dimensions and high speed of microchip separations

Summary of the 9th Workshop on [email protected]

The [email protected] workshop (MRT) series offers a discussion forum for the rising need to leverage modeling techniques at runtime for the software of the future. MRT has become a mature research topic, which is, e.g., reflected in separate sessions at conferences covering MRT approaches only. The target venues of the workshops audience changed from workshops to conferences. Hence, new topics in the area of MRT need to be identified, which are not yet mature enough for conferences. In consequence, the main goal of this edition was to reflect on the past decade of the workshop's history and to identify new future directions for the workshop

Summary of the 10th International workshop on [email protected]

The 10th anniversary of the workshop [email protected] was held at the 18th International Conference on Model Driven Engineering Languages and Systems. The workshop took place in the city of Ottawa, Canada, on the 29th of September 2015. The workshop was organized by Sebastian Gtz, Nelly Bencomo, Gordon Blair and Hui Song. Here, we present a summary of the discussions at the workshop and a synopsis of the topics discussed and highlighted during the workshop. The workshop received the award for the best workshop at the MODELS 2015 conference out of 18 workshops in total. The award was based upon the organization, program, web site timing and the feedback provided by the workshop participants

Summary of the 8th International workshop on [email protected]

The 8th edition of the workshop [email protected] was held at the 16th International Conference MODELS. The workshop took place in the city of Miami, USA, on the 29th of September 2013. The workshop was organised by Nelly Bencomo, Sebastian Götz, Robert France and Bernhard Rumpe. Here, we present a summary of the workshop and a synopsis of the papers discussed during the workshop

Summary of the 11th international workshop on [email protected]

After last years anniversary, this year the 11th edition of the workshop [email protected] was held at the 19th International Conference on Model Driven Engineering Languages and Systems. The workshop took place in the city of Saint Malo, France, on the 4th of October 2016. The workshop was organized by Sebastian Götz, Nelly Bencomo, Kirstie Bellman and Gordon Blair. Here, we present a summary of the discussions at the workshop and a synopsis of the topics discussed and highlighted during the workshop

Summary of the 12th international workshop on [email protected]

This year the 12th edition of the workshop [email protected] was held at the 20th International Conference on Model Driven Engineering Languages and Systems. The workshop took place in the city of Austin, Texas, USA, on the 18th of September 2017. The workshop was organized by Sebastian Götz, Nelly Bencomo, Kirstie Bellman and Gordon Blair. Here, we present a summary of the workshop and a synopsis of the topics discussed and highlighted during the workshop

Influencing factors on agricultural transports and their effect on energy consumption and average speed

This article deals with the importance of transportation in agriculture, focusing on energy consumption and average speed of different agricultural transport vehicles. Transportation of goods is an important section of both logistics and agricultural production; therefore this article concentrates on the linkage of these two fields of study – agriculture and logistics. Against this background, current trends in logistics and their significance for and impact on agriculture are defined first. The presented data were collected via a road trial comparing agricultural transport vehicles to those commonly deployed in road haulage. The advantages of the well-established tractor lie – of course – in its high cross-country mobility and the many resulting fields of application on agricultural production. The off-road attributes of the tractor combined with the high level of soil protection are characteristics highly in its favor, especially when applying a single phase harvesting system. With multiphase transport chains on the other hand, the deployment of trucks can be the sensible choice because of their higher average speed and lesser fuel consumption compared to the tractor. Furthermore, the motorization of the tractor is a factor to be considered when choosing the right transport system, since a comparison between two forms of motorization showed clear differences in their road performance.   Keywords: agricultural transports, energy consumption, average transport speed, transport vehicle comparison

Comparing Mobile Applications' Energy Consumption

As mobile devices are nowadays used regularly and everywhere, their energy consumption has become a central concern for their users. However, mobile applications often do not consider energy requirements and users have to install and try them to reveal information on their energy behavior. In this paper, we compare mobile applications from two domains and show that applications reveal different energy consumption while providing similar services. We define microbenchmarks for emailing and web browsing and evaluate applications from these domains. We show that non-functional features such as web page caching can but not have to have a positive influence on applications' energy consumption