The TV-WEB project - combining internet and television – lessons learnt from the user experience studies

We present the results of the user experience studies conducted as part of the European SEE TV-WEB project activities. The SEE TV-WEB project aims to use the free digital terrestrial television (DTT) broadcasting frequency spectrum capacities for transmitting selected Internet content and ensuring at least some Internet experience via TV devices to the certain less advantaged segments of the population, or those in rural areas without broadband access. Five different test study cases are presented, four in Slovenia and one in Austria, each with different specific target user groups and their own dynamics. According to the project disposition goals the focus was on the elderly. Methods, such as think-aloud protocol in combination with a guided interview and observation of verbal as well as of non-verbal responses, were used. To ensure the repeatability of tests and to help guide the process, a special questionnaire was developed. The research questions focused on: the navigation and interaction concept, the content, the readability, and the overall acceptance and the perception of value of the TV-WEB service. More than 74 users participated in the user experience studies, 27 of them 65 years old or older. The results indicate that the presented navigation and interaction concept is indeed intuitive and simple enough to be used by most users with no or little effort. This is especially proven by the results from studies at both elderly citizens homes, where the majority of participants were 65 years old or older.     

Two-step dynamic programming approach for optimal irrigation water allocation

A two-step (deterministic and stochastic) dynamic programming approach has been introduced in this study to solve the complex problem of optimal water allocation in a run-of-the-river-type irrigation project. The complexity of a real-world situation is represented by incorporating in the optimization model the stochasticity of water supply and the nonlinearity of crop production functions. A nonlinear, dated, and multiplicative production function is transformed into a sequentially additive type to replace the usual method of creating an additional state of the plant variable which only increases the dimension of the problem. As compared to the explicit stochastic dynamic programming which necessitates, along with its use, an enormous computational complexity due to the so-called curse of dimensionality, the present model can approximate the theoretical global optimum, at least for the present case study, with a dramatic reduction in computer processing time. It also eliminates the rigidity of the policy derived by the explicit approach, since it provides irrigation planners with alternative decision policies which incorporate intangibles and other nonengineering factors. The traditional method of fixing the cropping pattern based on deterministic estimates of a dependable water supply can likewise be evaluated by the use of the present model. The results of the model's application appear to be practically acceptable.     

六方氮化硼改性ABS材料的制备及性能研究

本文采用微米级六方氮化硼(h-BN)对ABS树脂进行共混改性。通过FT-IR和SEM测试表征h-BN改性ABS材料物性及微观结构,并考察了h-BN对ABS树脂力学、导热和表面摩擦性能的影响。研究发现,随着h-BN增加,改性ABS材料韧性下降,而材料刚性提升。添加4wt%h-BN改性ABS悬臂梁缺口冲击强度为12.2 k J/m2,弯曲模量高达2800 MPa,导热系数为0.312 W/m K,静摩擦系数为0.30,滑动摩擦系数为0.25。因此,h-BN改性ABS材料具有较强的力学强度、亮白的外观、良好的导热和较低的摩擦系数等性能,更适合用于制作家电和电子电器等消费品的外观制件。     

User identification approach based on simple gestures

We present an intuitive, implicit, gesture based identification system suited for applications such as the user login to home multimedia services, with less strict security requirements. The term “implicit gesture” in this work refers to a natural physical hand manipulation of the control device performed by the user, who picks it up from its neutral motionless position or shakes it. For reference with other related systems, explicit and well defined identification gestures were used. Gestures were acquired by an accelerometer sensor equipped device in a form of the Nintendo WiiMote remote controller. A dynamic time warping method is used at the core of our gesture based identification system. To significantly increase the computational efficiency and temporal stability, the “super-gesture” concept was introduced, where acceleration features of multiple gestures are combined in only one super-gesture template per each user. User evaluation spanning over a period of 10 days and including 10 participants was conducted. User evaluation study results show that our algorithm ensures nearly 100 % recognition accuracy when using explicit identification signature gestures and between 88 % and 77 % recognition accuracy when the system needs to distinguish between 5 and 10 users, using the implicit “pick-up” gesture. Performance of the proposed system is comparable to the results of other related works when using explicit identification gestures, while showing that implicit gesture based identification is also possible and viable.     

Fruit recognition from images using deep learning applications

Multimedia Tools and Applications - Smart imaging devices have been used at a rapid rate in the agriculture sector for the last few years. Fruit recognition and classification is noticed as one of...     

Ordering of fluorite-type phases in erbium-doped oxyfluoride glass ceramics

In this study, novel transparent Er³⁺ doped glass ceramics were prepared from melt-quenched oxyfluoride glasses with general composition of Na₂O-NaF-BaF₂-YbF₃-Al₂O₃-SiO₂. The crystallization of fluorite (BaF₂, BaF₂-YbF₃, NaF-BaF₂-YbF₃ and Na_0.5-xYb_0.5+xF_2+2x) and distorted fluorite (rhombohedral Ba₄Yb₃F₁₇ and tetragonal NaF-BaF₂-YbF₃) phases was analysed in glass ceramics with different BaF₂ and YbF₃ ratio. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Intense red upconversion luminescence (UCL) was detected under near-infrared excitation resulting from three photon upconversion followed by cross-relaxation between Er³⁺ and Yb³⁺ ions.The local environment of Er³⁺ ions in fluorite and distorted phases was analysed using site-selective spectroscopy. The Er³⁺ ions were found to act as nucleation centres in the glass ceramics containing BaF₂. The phase transition from metastable fluorite to rhombohedrally and tetragonally distorted fluorite phases was detected using Er³⁺ ions as a probe.     

Effect of VR technology matureness on VR sickness

In this paper relationship of perceived virtual reality (VR) sickness phenomenon with different generations of virtual reality head mounted displays (VR HMD) is presented. Action content type omnidirectional video clip was watched by means of four HMDs of different levels of technological matureness, with a 2D monitor used as a reference point. In addition to subjective estimation of VR sickness effects by means of the SSQ questionnaire, psychophysiology of the participants was monitored. Participant’s electrodermal activity, heart rate, skin temperature and respiration rate were measured. Results of the study indicate differences between HMDs in both SSQ score and changes of physiology. Skin conductance was found to be significantly correlated with VR sickness. Mobile HMD did not induce significantly higher levels of VR sickness. Disorientation SSQ was proven to be a useful tool for assessing the VR sickness effects.

     

Boundary integral equations for thin bodies

A boundary integral equation formulation for thin bodies which uses CBIE (conventional BIE) only is well known to be degenerate. A mixed formulation for a thin rigid scatterer which combines CBIE and HBIE (hypersingular BIE) is motivated by examining the discretized form of the integral equations, and this formulation is shown to be non-degenerate for thin non-rigid inclusion problems. A near-singular integration procedure, useful for singular integrals as well, is presented. Finally, numerical examples for acoustic wave scattering from rigid and soft scatterers are presented.     

Development of hydrological tools using extreme rainfall events for Dhaka,Bangladesh

Annual daily maximum rainfall data for 57 years (1953 to 2009) in Dhaka, Bangladesh are analysed statistically to prepare two hydrological tools: (1) probable return periods of extreme rainfall events, and (2) intensity-duration-frequency (IDF) curves. Limited availability of short-duration rainfall data leads to difficulties in performing the task through traditional approaches; hence, the Gumbel distribution function and scaling theory have been applied in preparing the probable return periods of extreme rainfall events and IDF curves, respectively. The outcomes of this paper can be used in better designing hydraulic structures in Bangladesh.