The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Weyl point is a topological point in three dimension momentum space and each Weyl point acts as a monopole of Berry flux. Weyl points with topological charges of the same sign can merge in the momentum space to forma multi Weyl point if certain symmetry conditions are satisfied. Here, we show that Weyl points with topological charges 1 and 2 can be found in a certain class of photonic crystals. Such...
An X-band optically-steered phased array radar is developed to demonstrate high resolution multi-target detection. The beam forming is implemented based on wavelength-swept true time delay (TTD) technique. The beam forming system has a wide direction tuning range of ±54°, low magnitude ripple of ±0.5 dB and small delay error of 0.13 ps/nm. To further verify performance of the proposed optically-steered...
Based on the Babinet Principle, a new metamaterial sensor is proposed in microwave region. The main part of the device is a microstrip coupled complementary asymmetric double-split resonator (CADSR). In this device, an extremely sharp resonance have been obtained due to the excitation of “trapped modes”. From the analysis, the effect of the degree of asymmetry on the frequency response and Q-Factor...
Image pre-processing is the critical step in the ship target identification of ISAR images, which consists of speckle noise suppression and stripe noise suppression. In this paper, a pre-processing method of speckle noise and stripe noise suppression is proposed. For speckle noise estimation, an adaptive initial threshold is generated based on hypothesis of Rayleigh distribution, and the second segmentation...
With the fast growth in smart phones, tablets and apps markets, the competition is increasing between market platform such as Android and iOS. And the growth numbers of apps available and downloaded, the competition between app market platforms are also very intensive. The economic behaviours of participants are determined by market factors, such as the effects of the number of apps available in the...
In this study, we focus on the investigations of oil slicks observed by TerraSAR-X and TanDEM-X operating over the drilling platforms in Forties oil field, the largest one in the North Sea. Previous researches indicate that oil spills observed by consecutive SAR images represent the same leaks, but in this paper, we presented four cases which suggest completely different situations of oil spill variations...
The TerraSAR-X and TanDEM-X (TSX/TDX) satellites adopt the HELIX operation manner of formatted flight to form a mono-rail dual antenna system for earth observation. In the monostatic mode, TSX/TDX operates independently, and the time interval for the observation over the same region is relatively short. Therefore, using TSX and TDX monostatic mode data, we can apply the maximum cross-correlation (MCC)...
Synthetic Aperture Radar (SAR) imaging can suffer distortion in the presence of phase errors in the acquired signal data caused by the non-ideal platform motion trajectory. Autofocus algorithms are used to remove the undesired phase error through signal processing techniques. Multi-channel convolution model of the SAR autofocus problem is established on the condition that phase error is range-independent...
Urban built-up area information is pivotal to understand complex drivers and mechanisms in global climate change application. However, built-up area extraction using Landsat time series data is a challenging task due to spatial-temporal expression and modeling of land cover types. To provide insights into the intra-annual dynamics of land use change, focusing on how time series characteristics improves...
Sea ice charts are provided operationally by the Canadian Ice Service (CIS) for the convenience of people in high-latitude regions. Hence, approaches to ice-water discrimination are in demand. An approach is proposed in this paper, in which no manual interpretation is involved in the selection of training data. It is done based on the discrepancy of incidence angle dependence between sea ice and open...
Pantograph-catenary dynamics performance determined the current receiving quality. In this paper, the pantograph-catenary dynamics model is established according to CED160D pantograph and simple chain contaction catenary based on ADAMS. The operating state of the train is used as the excitation load to the model. We extract important current receiving parameters such as the contact force of the pantograph...
In recent years, global tidal power industry is developing rapidly in the case that the working environment of tidal turbines is extremely complicated and turbines are affected by the fluctuation of current speed and load, so its vibration signal is non-stationary, nonlinear and time-varying. Besides tidal turbines maintenance costs have been high all the time, which seriously restricts the healthy...
Currently the research of face recognition mostly aim on little internal face of simple environment and carried out on single computer, which limited the application of face recognition. The emergence of big data technology make parallel compute more easy, which make big scale compute work could be accomplished in very short time. An dynamic face recognition system was put forward in this paper. The...
This paper is focus on the massive face recognition. We want to recognize a face from a lot of faces at public location. There are two kinds of techniques are used to hit the goal: one is the 3D face detection technique and the other is the Hadoop technique. Face detection technique find a similar face by 3D face features form mass face data. The Hadoop is a parallel processing structure, it can enhance...
The high frequency surface wave radar (HFSWR) plays an important role in marine surveillance. However, the weak targets detection for HFSWR is a hard problem. To address such a problem, this paper focuses on the weak target detection method, which extends the idea of reverse phase transition into complex Duffing oscillator in order to improve the detection accuracy. Furthermore, for the sake of detection...
Mobile robots are capable of performing spatial displacement motions in different environments. These motions can be computed based on the sensorial data (autonomous robot) or given by an operator (tele operated robot). This paper is focused on the latter providing the control and software architecture that bridges the tele operator, the sensorial data from the task circumstance and the robot's locomotion...
Rapid tooling (RT) technology can effectively improve the production efficiency and market competitiveness of enterprises, but the forming process of RT is influenced by many factors, which is a typical weak theoretical strong experience field, How to introduce the expert knowledge and experience into RT forming process is the key to improve product quality. However, due to lack of the information...
Due to the rising competition in budget hotel sector, it becomes more and more imperative for service providers to increase their competitiveness. Nowadays, customers have put more attention to satisfy their feelings. Therefore, service designers need to investigate customers' real feelings and improve their services to meet customers' needs. In this paper, the Kansei Engineering (KE), a tool for...
To monitor virtual machines and applications in IaaS cloud environments, cloud providers require installing agents in tenants' virtual machines. It is inconvenient for users and is prone to cyber attacks. In this paper, we propose oMon, a out-of-the-box application monitoring framework for cloud applications. oMon does not requires installing any agent in the guest OS of tenants' virtual machines,...
In this work, a feasible multi-VT modulation strategy in vertical nanowire FETs (VNWFETs) combining asymmetric halo doping with nanowire diameter is proposed and verified by TCAD simulation. The results show that halo configuration close to source side exhibits larger VT-tuning range and better SCE controlling. Moreover, adjustment of halo doping concentration and nanowire diameters can be adopted...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.