Exact colouring algorithm for weighted graphs applied to timetabling problems with lectures of different lengths

An exact algorithm is presented for determining the interval chromatic number of a weighted graph. The algorithm is based on enumeration and the Branch-and-Bound principle. Computational experiments with the application of the algorithm to random weighted graphs are given. The algorithm and its modifications are used for solving timetabling problems with lectures of different lengths

True zero-training brain-computer interfacing: an online study

Despite several approaches to realize subject-to-subject transfer of pre-trained classifiers, the full performance of a Brain-Computer Interface (BCI) for a novel user can only be reached by presenting the BCI system with data from the novel user. In typical state-of-the-art BCI systems with a supervised classifier, the labeled data is collected during a calibration recording, in which the user is asked to perform a specific task. Based on the known labels of this recording, the BCI's classifier can learn to decode the individual's brain signals. Unfortunately, this calibration recording consumes valuable time. Furthermore, it is unproductive with respect to the final BCI application, e.g. text entry. Therefore, the calibration period must be reduced to a minimum, which is especially important for patients with a limited concentration ability. The main contribution of this manuscript is an online study on unsupervised learning in an auditory event-related potential (ERP) paradigm. Our results demonstrate that the calibration recording can be bypassed by utilizing an unsupervised trained classifier, that is initialized randomly and updated during usage. Initially, the unsupervised classifier tends to make decoding mistakes, as the classifier might not have seen enough data to build a reliable model. Using a constant re-analysis of the previously spelled symbols, these initially misspelled symbols can be rectified posthoc when the classifier has learned to decode the signals. We compare the spelling performance of our unsupervised approach and of the unsupervised posthoc approach to the standard supervised calibration-based dogma for n = 10 healthy users. To assess the learning behavior of our approach, it is unsupervised trained from scratch three times per user. Even with the relatively low SNR of an auditory ERP paradigm, the results show that after a limited number of trials (30 trials), the unsupervised approach performs comparably to a classic supervised model

Shunting passenger trains: getting ready for departure

In this paper we consider the problem of shunting train units on a railway station. Train units arrive at and depart from the station according to a given train schedule and in between the units may have to be stored at the station. The assignment of arriving to departing train units (called matching) and the scheduling of the movements to realize this matching is called shunting. The goal is to realize the shunting using a minimal number of shunt movements.\ud For a restricted version of this problem an ILP approach has been presented in the literature. In this paper, we consider the general shunting problem and derive a greedy heuristic approach and an exact solution method based on dynamic programming. Both methods are flexible in the sense that they allow the incorporation of practical planning rules and may be extended to cover additional requirements from practice

Emotional Responses to Multisensory Environmental Stimuli: A Conceptual Framework and Literature Review.

How we perceive our environment affects the way we feel and behave. The impressions of our ambient environment are influenced by its entire spectrum of physical characteristics (e.g., luminosity, sound, scents, temperature) in a dynamic and interactive way. The ability to manipulate the sensory aspects of an environment such that people feel comfortable or exhibit a desired behavior is gaining interest and social relevance. Although much is known about the sensory effects of individual environmental characteristics, their combined effects are not a priori evident due to a wide range of non-linear interactions in the processing of sensory cues. As a result, it is currently not known how different environmental characteristics should be combined to effectively induce desired emotional and behavioral effects. To gain more insight into this matter, we performed a literature review on the emotional effects of multisensory stimulation. Although we found some interesting mechanisms, the outcome also reveals that empirical evidence is still scarce and haphazard. To stimulate further discussion and research, we propose a conceptual framework that describes how environmental interventions are likely to affect human emotional responses. This framework leads to some critical research questions that suggest opportunities for further investigation

Zero training for BCI – Reality for BCI systems based on event-related potentials

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.This contribution reviews how usability in Brain- Computer Interfaces (BCI) can be enhanced. As an example, an unsupervised signal processing approach is presented, which tackles usability by an algorithmic improvement from the field of machine learning. The approach completely omits the necessity of a calibration recording for BCIs based on event-related potential (ERP) paradigms. The positive effect is twofold - first, the experimental time is shortened and the productive online use of the BCI system starts as early as possible. Second, the unsupervised session avoids the usual paradigmatic break between calibration phase and online phase, which is known to introduce data-analytic problems related to non-stationarity

Implantation of an Elastic Ring at Equator of the Left Ventricle Influences Cardiac Mechanics in Experimental Acute Ventricular Dysfunction

ObjectivesWe hypothesize that the implantation of an endoventricular elastic ring at the left ventricle (LV) equatorial site will positively affect the cardiac mechanics in an experimental model of acute LV dysfunction.BackgroundChanges in the elastic properties of LV occur in the dilated and failing heart, contributing to overall cardiac mechanical dysfunction. No interventions are as yet specifically designed to improve LV elasticity in failing hearts.MethodsAcute LV enlargement and dysfunction was induced in 13 healthy sheep via the insertion of a large Dacron patch into the lateral wall. In 6 of these sheep, a customized elastic ring was implanted at the inner surface of the LV equator (ring group), and the remaining 7 served as control subjects (dysfunction group). Systolic and diastolic function was evaluated using echocardiography and pressure–volume (P–V) analysis.ResultsIn the ring group, both the maximum rate of pressure increase and the slope of end-systolic P–V relationship were significantly different from those without ring (1,718 ± 726 vs. 1,049 ± 269 and 1.25 ± 0.30 vs. 0.88 ± 0.19; both p < 0.05). Preload recruitable stroke work changed even more prominently (33 ± 11 vs. 17 ± 5; p = 0.005), along with stroke volume, ejection fraction, and stroke work. Although ring implantation had no effect on end-diastolic P–V relationship, it positively affected the active component of diastole: the maximum rate of pressure decrease declined significantly (p = 0.037). The time constant of relaxation tended to decrease (37 ± 8 vs. 44 ± 6; p = 0.088).ConclusionsImproving the elastic component of the LV at its equatorial site substantially augments contractility and early relaxation in acute systodiastolic LV dysfunction

The e-harbours journey: Point of arrival; smart energy networks in the North Sea Region.

The twenty-eight member states of the European Union have agreed upon ambitious targets that address climate change, energy security and economic competitiveness. Can "smart energy networks" help to speed up the energy transition? This question has been the focus of the e-harbours project, formed by eight partners from seven harbours located in five countries around the North Sea. Large industrial cities and harbour areas, with a dense variety of production and consumption processes, are a perfect testing ground for smart energy concepts. The aim of e-harbours is to explore the possibilities for large-scale implementation of smart energy networks, specifically through four pillars of energy optimisation: 1. optimal capacity in the system for additional renewable energy, which is intermittent by nature; 2. a strong improvement in energy efficiency, supporting savings; 3. the integration of electric mobility, reducing fossil fuels and possibly adding a buffer to the grid; 4. enhanced stability for the energy network and greater energy security. This report presents an overview of the e-harbours project journey, including a presentation of the main findings and recommendations