Christian Koehler

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Smart devices are becoming increasingly commercially available. However, uptake of these devices has been slow and abandonment swift, which indicates that smart devices may not currently meet the needs of users. To advance an understanding of the ways users benefit from, are challenged by, and abandon smart devices, we asked a group of users to purchase(More)
Reducing the large energy consumption of temperature regulation systems is a challenge for researchers and practitioners alike. In this paper, we explore and compare two common types of solutions: A manual systems that encourages reduced energy use, and an intelligent automatic control system. We deployed an eco-feedback system with the ability to remotely(More)
Occupancy count in rooms is valuable for applications such as room utilization, opportunistic meeting support, and efficient heating-cooling operations. Few buildings, however, have the means of knowing occupancy beyond simple binary presence-absence. In this paper we present the <i>PerCCS</i> algorithm that explores the possibility of estimating person(More)
Location prediction enables us to use a person's mobility history to realize various applications such as efficient temperature control, opportunistic meeting support, and automated receptionists. Indoor location prediction is a challenging problem, particularly due to a high density of possible locations and short transition distances between these(More)
Mobile phones allow us to reach people anywhere, at anytime. In addition to the benefits for end users, researchers and developers can also benefit from the powerful devices that participants carry on a daily basis. Collectively, mobile phones form a ubiquitous computer. Ubiquitous Mobile Instrumentation (UbiMI) workshop focuses on using mobile devices as(More)
The complexity of image processing tasks has risen during the last years. To counteract this trend, we introduce the novel Domain Specific Language GU-DSL allowing to shorten the time-to-market and improving the development process. Therefor we use some base concepts of Java and C#, adopting the idea of encapsulating classes and flowmodels using diagrams as(More)
Rising power demands resulting from technological advancements is an increasingly important global issue. One way to tackle this problem is to motivate individual behavior change, for which the ubiquity of mobile phones offer an ideal platform to influence consumption behavior of users. In this paper we explore the possibilities for using timely(More)
Setting up new data and image processing systems is an always recurring task. Since reusing algorithms and other functionality leads to higher program quality and mostly shorter development time, this approach introduces a novel Component-Based Software Engineering System (CBSE). It supports special types such as diagrams and structures, components and(More)
Mobile phones allow us to reach people anywhere, anytime. In addition to the benefits for end users, researchers and developers can also benefit from the powerful devices that people carry on a daily basis. Collectively, mobile phones form a ubiquitous computer. The Ubiquitous Mobile Instrumentation (UbiMI) workshop focuses on using mobile devices as(More)