Robust designs for polynomial regression by maximizing a minimum of D - and D 1-efficiencies

In the common polynomial regression of degree m we determine the design which maximizes the minimum of the D-efficiency in the model of degree m and the D1 -efficiencies in the models of degree

Natural environment and land use in the Chad Basin, NE-Nigeria : preliminary results of an interdisciplinary research

The objective of this paper is to combine the environmental conception of the Kanuri with detailed findings of pedological and botanical field investigations. Interpretation of multitemporal satellite data and aerial photographs should provide land cover and land use information for an extended area. The area of investigation was outlined within the transitional zone from the clay plains to the sandy areas by interpretation of satellite images. The presented subset of a SPOT-XS-satellite image shows part of the Marte Local Government Area with its capital Old Marte in the north-eastern part of the image. The darker colours represent the clay plains while the lighter parts are related to the sandy areas. Almost half of the research area is covered by clay but all settlements are located on the slightly elevated sandy areas. Within these sandy areas different gray shades demonstrate the pattern of the rainy season farming area. Differences in colour within the clay plains are mainly due to variances in soil, water content and vegetation cover. In the north-eastern part of the image irrigation channels of the South Chad Irrigation Project are visible. The main attention, especially of the pedological and botanical research, was directed towards the south-western part of the subset in the vicinity of the villages of Wulwa, Dura, Kajere and Ngubdori

Change point testing for the drift parameters of a periodic mean reversion process

In this paper we investigate the problem of detecting a change in the drift parameters of a generalized Ornstein-Uhlenbeck process which is defined as the solution of dX_t = (L(t) - alpha X_t)dt + delta dB_t and which is observed in continuous time. We derive an explicit representation of the generalized likelihood ratio test statistic assuming that the mean reversion function L(t) is a finite linear combination of known basis functions. In the case of a periodic mean reversion function, we determine the asymptotic distribution of the test statistic under the null hypothesis

Accuracy and Immersion Improvement of Hybrid Motion Capture based Real Time Virtual Validation

AbstractUsing a digital human model for dynamic analysis is due to the high modelling complexity in digital environments not very prevalent. The movement of the worker is either unrealistic, or time-consuming to realize. Therefore, the need for research is a time saving possibility to explore virtual validation by a human model taking advantage of a nonetheless realistic movement design. To achieve this goal, we use an experimental setup including both a hybrid motion capture system and an interface for the connection to digital validation software. The motion capturing in connection along with the validation software allows real time modelling respectively tracking and therefore a realistic movement of the human model. To get good results while applying the motion capturing approach in mixed reality situations, it is necessary to have an exact registration between the real and virtual environment. Hence, the experimental setup must be designed for both. The key challenge here is to superimpose the CAD data with the real objects used for haptic feedback and better immersion. To realize an optimal registration we use a laser tracker solution

Time Travel Gamification of Learning and Training: From Theoretical Concepts to Practical Applications

Gamification is considered the systematic anticipation and design of affective experiences. It is not erroneously reduced to the usage of game-typical elements in another context. The human experiences in focus are varying forms of virtual time travel. In a time travel exploratory game, players return virtually to the past for gaining insights and, possibly, finding artifacts bring back to the present time. This works well for environmental education studying, by way of illustration, the worldwide ocean warming over several decades. Time travel prevention games go even further. Players who visit the past get an opportunity to impact their fate. This works well in application areas such as crime prevention and industrial accident prevention. Dynamic time travel prevention games are a recently developed game type in which the past changes dynamically to support the player’s chances of successfully completing the mission. The authors present original concepts and technologies and demonstrate running applications

Untersuchung der Trocknungsluftströmung an einer neu entwickelten Geometrie für Dächerschachttrockner

Der Dächerschachttrockner wurde in den letzten Jahren hinsichtlich der Trocknungseffizienz, Regelungstechnik und Leistungssteigerung vielfach analysiert. Dennoch besteht erheblicher Optimierungsbedarf bezüglich Energieeffizienz und Gleichmäßigkeit der Trocknung. Zur Analyse des spezifischen Energieverbrauchs und der Homogenität des Trocknungsprozesses wurden thermodynamische Prozesszustände anhand der konventionellen Trocknergeometrie numerisch und experimentell analysiert. Aus den gewonnenen Ergebnissen wurde eine neue Trocknergeometrie entwickelt, mit der eine deutliche Effizienzsteigerung erreicht werden soll. Wie die strömungsmechanische Analyse des ersten Designentwurfs ergab, ist weiterer Entwicklungsbedarf bis zur Praxisüberführung erforderlich. Während im Kernflussbereich in der Trocknermitte gleichmäßige Strömungsbedingungen nachgewiesen werden konnten, ist die Konstruktion in den wandnahen Bereichen zu optimieren.The mixed-flow dryer has been a matter of investigation many times regarding drying efficiency, dryer control, and performance enhancement over the past years. However, there is still considerable demand for optimization in terms of energy efficiency and homogeneity of drying. In order to analyze the specific energy consumption and the homogeneity of the drying process, different thermodynamic process conditions have been investigated for the conventional MFD design using numerical and experimental methods. Based on the results obtained, a novel dryer design has been developed. With this, a considerable increase of efficiency is expected. As the fluid dynamic analysis of the first design draft revealed, further development is required until scaling-up and transfer into practice will be possible. While homogeneous airflow conditions could be demonstrated in the core flow region in the center of the dryer, the configuration must be optimized in the near wall regions

High Figure‐of‐Merit Telluride‐Based Flexible Thermoelectric Films through Interfacial Modification via Millisecond Photonic‐Curing for Fully Printed Thermoelectric Generators

The thermoelectric generator (TEG) shows great promise for energy harvesting and waste heat recovery applications. Cost barriers for this technology could be overcome by using printing technologies. However, the development of thermoelectric (TE) materials that combine printability, high-efficiency, and mechanical flexibility is a serious challenge. Here, flexible (SbBi)2(TeSe)3-based screen-printed TE films exhibiting record-high figure of merits (ZT) and power factors are reported. A high power factor of 24 µW cm−1 K−2 (ZTmax ≈ 1.45) for a p-type film and a power factor of 10.5 µW cm−1 K−2 (ZTmax ≈ 0.75) for an n-type film are achieved. The TE inks, comprised of p-Bi0.5Sb1.5Te3 (BST)/n-Bi2Te2.7Se0.3 (BT) and a Cu-Se-based inorganic binder (IB), are prepared by a one-pot synthesis process. The TE inks are printed on different substrates and sintered using photonic-curing leading to the formation of a highly conducting β-Cu2−δSe phase that connects “microsolders,” the grains resulting in high-performance. Folded TEGs (f-TEGs) are fabricated using the materials. A half-millimeter thick f-TEG exhibits an open-circuit voltage (VOC) of 203 mV with a maximum power density (pmax) of 5.1 W m−2 at ∆T = 68 K. This result signifies that a few millimeters thick f-TEG could power Internet-of-Things (IoTs) devices converting low-grade heat to electricity