A Context-Aware Adaptive Streaming Media Distribution System in a Heterogeneous Network with Multiple Terminals

We consider the problem of streaming media transmission in a heterogeneous network from a multisource server to home multiple terminals. In wired network, the transmission performance is limited by network state (e.g., the bandwidth variation, jitter, and packet loss). In wireless network, the multiple user terminals can cause bandwidth competition. Thus, the streaming media distribution in a heterogeneous network becomes a severe challenge which is critical for QoS guarantee. In this paper, we propose a context-aware adaptive streaming media distribution system (CAASS), which implements the context-aware module to perceive the environment parameters and use the strategy analysis (SA) module to deduce the most suitable service level. This approach is able to improve the video quality for guarantying streaming QoS. We formulate the optimization problem of QoS relationship with the environment parameters based on the QoS testing algorithm for IPTV in ITU-T G.1070. We evaluate the performance of the proposed CAASS through 12 types of experimental environments using a prototype system. Experimental results show that CAASS can dynamically adjust the service level according to the environment variation (e.g., network state and terminal performances) and outperforms the existing streaming approaches in adaptive streaming media distribution according to peak signal-to-noise ratio (PSNR)

An investigation on nitrogen uptake and microstructure of equimolar quaternary FeCoNiCr high entropy alloy after active-screen plasma nitriding

Under nitrogen diffusion treatments, N-expanded austenite (γN) can form at the surface of self-passivating Fe-Cr, Ni-Cr, and Co-Cr alloys at low temperatures, which provides beneficial hardening and enhancements in wear resistance without reducing corrosion resistance. Given the wide research interests in multicomponent equimolar alloys, an equimolar quaternary FeCoNiCr high entropy alloy (HEA) was investigated after active-screen plasma nitriding at 430–480 °C in this study. Firstly, the formation of γN-FeCoNiCr case at 430 °C was demonstrated with the bright case appearance after metallographic etching, the lattice expansion under XRD, the FCC electron diffraction patterns and the shear bands under TEM. Secondly, the thick treatment cases at ∼9–16 μm first indicated that N interstitial diffusion was not sluggish in the FeCoNiCr surface. Thirdly, analogous to stainless steels, the onset of dark regions in the etched γN-FeCoNiCr case was owing to the formation of a cellular mixture of CrN + γ-(Fe, Co, Ni) nano-lamellae at elevated treatment temperatures. The residual bright regions in γN-FeCoNiCr at 480 °C showed ∼1–3 nm CrN nanoprecipitates with no substantial Cr segregation. Additionally, a significant nanocrystalline layer was seen at the topmost surface at 480 °C, which is most likely associated with the high substrate Cr content

Topology-Preserving Adversarial Training

Despite the effectiveness in improving the robustness of neural networks, adversarial training has suffered from the natural accuracy degradation problem, i.e., accuracy on natural samples has reduced significantly. In this study, we reveal that natural accuracy degradation is highly related to the disruption of the natural sample topology in the representation space by quantitative and qualitative experiments. Based on this observation, we propose Topology-pReserving Adversarial traINing (TRAIN) to alleviate the problem by preserving the topology structure of natural samples from a standard model trained only on natural samples during adversarial training. As an additional regularization, our method can easily be combined with various popular adversarial training algorithms in a plug-and-play manner, taking advantage of both sides. Extensive experiments on CIFAR-10, CIFAR-100, and Tiny ImageNet show that our proposed method achieves consistent and significant improvements over various strong baselines in most cases. Specifically, without additional data, our proposed method achieves up to 8.78% improvement in natural accuracy and 4.50% improvement in robust accuracy

Acceptor plane expansion enhances horizontal orientation of thermally activated delayed fluorescence emitters.

Manipulating orientation of organic emitters remains a formidable challenge in organic light-emitting diodes (OLEDs). Here, expansion of the acceptor plane of thermally activated delayed fluorescence (TADF) emitters was demonstrated to selectively modulate emitting dipole orientation. Two proof-of-the-concept molecules, PXZPyPM and PXZTAZPM, were prepared by introducing a planar 2-phenylpyridine or 2,4,6-triphenyl-1,3,5-triazine substituent into a prototypical molecule (PXZPM) bearing a pyrimidine core and two phenoxazine donors. This design approach suppressed the influence of substituents on electronic structures and associated optoelectronic properties. Accordingly, PXZPyPM and PXZTAZPM preserved almost the same excited states and similar emission characteristics as PXZPM. The expanded acceptor plane of PXZPyPM and PXZTAZPM resulted in a 15 to 18% increase in horizontal ratios of emitting dipole orientation. PXZPyPM supported its green device exhibiting an external quantum efficiency of 33.9% and a power efficiency of 118.9 lumen per watt, competitive with the most efficient green TADF OLEDs reported so far

Research Roadmap of Service Ecosystems: A Crowd Intelligence Perspective

With the mutual interaction and dependence of several intelligent services, a crowd intelligence service network has been formed, and a service ecosystem has gradually emerged. Such a development produces an ever-increasing effect on our lives and the functioning of the whole society. These facts call for research on these phenomena with a new theory or perspective, including what a smart society looks like, how it functions and evolves, and where its boundaries and challenges are. However, the research on service ecosystems is distributed in many disciplines and fields, including computer science, artificial intelligence, complex theory, social network, biological ecosystem, and network economics, and there is still no unified research framework. The researchers always have a restricted view of the research process. Under this context, this paper summarizes the research status and future developments of service ecosystems, including their conceptual origin, evolutionary logic, research topic and scale, challenges, and opportunities. We hope to provide a roadmap for the research in this field and promote sound development

Control Effect of Deposition Processes on Shale Lithofacies and Reservoirs Characteristics in the Eocene Shahejie Formation (Es4s), Dongying Depression, China

The lacustrine fine-grained sedimentary rocks in the upper interval of the fourth member of the Eocene Shahejie Formation (Es4s) in the Dongying Depression are important shale oil exploration targets in Bohai Bay Basin. They are widely distributed and rich in organic matter. In this study, samples were observed under the optical microscope and FESEM, combined with geochemical test and physical property analysis to study the sedimentary characteristics and reservoir characteristics of them. Nine lithofacies are recognized based on the mineral composition, the content of organic matter and the beddings. The middle-high organic laminated calcareous fine-grained sedimentary rocks (LF1) and the middle-high organic laminated mixed fine-grained sedimentary rocks (LF2) resulted from seasonal sediment variations and settled by suspension in the deep lake. The middle-high organic flaggy mixed fine-grained sedimentary rocks (LF3), the middle-high organic flaggy calcareous fine-grained sedimentary rocks (LF4), the middle-high organic massive calcareous fine-grained sedimentary rocks (LF5) and the middle organic massive mixed fine-grained sedimentary rocks (LF6) were formed by redeposition. The low organic massive argillaceous fine-grained sedimentary rocks (LF7), the low organic massive felsic fine-grained sedimentary rocks (LF8) and the low organic massive mixed fine-grained sedimentary rocks (LF9) are affected by the terrigenous input events. The pore structures vary in different beddings which are influenced by the kinds and arrangement of minerals and particles. In the laminated lithofacies, the ink-bottle-shaped pores are dominant. In the flaggy and massive lithofacies, the ink-bottle-shaped pores and the slit-shaped pores coexist. LF1 and LF2 are the best target for shale oil exploration and the LF3, LF4, LF5 and LF6 are the second. The deposition processes control the lithofacies and reservoir characteristics of the fined-grained sedimentary rocks

In-situ stress field of Fanzhuang coabed methane block in Qinshui Basin

Geostress is a crucial factor that affects the in-situ permeability and reservoir stimulation, and thus the performance of coalbed methane (CBM) recovery from coal. Therefore, a systematically investigation of in-situ geostress was made based on pressure-time records of the hydraulic fracturing of 238 CBM wells collected from Fanzhuang block in Qinshui Basin of China. The results indicate the vertical stress, maximum and the minimum horizontal principal stress range from 5.92 to 20.08 MPa, 8.03 to 41.75 MPa and 5.38 to 21.24 MPa, respectively. The gradient of the maximum horizontal stress and least horizontal stress vary from 14.16 to 77.82 kPa/m and from 11.12 to 41.43 kPa/m in respective. The relatively high horizontal principal stress zone concentrates in the NE trending within the middle of the block, while the relatively low-stress zone distributes in west, east and south of the block. The analysis of the microseismic fracture monitoring from 72 CBM wells shows that the orientation of the maximum horizontal principal stress concentrates in the NEE similar to NE direction and locally distorted by the faults, which can be further used to optimize the CBM well drilling, completion and stimulation in the studied area