The existing deep hashing methods of content-based speech retrieval do not make enough use of supervised information and have the suboptimal generated hash codes, low retrieval precision and low retrieval efficiency. To address the above problems, a triplet deep hashing method for speech retrieval was proposed. Firstly, the spectrogram image features were used as the input of the model in triplet manner to extract the effective information of the speech feature. Then, an Attentional mechanism-Residual Network (ARN) model was proposed, that is, the spatial attention mechanism was embedded on the basis of the ResNet (Residual Network), and the salient region representation was improved by aggregating the energy salient region information in the whole spectrogram. Finally, a novel triplet cross-entropy loss was introduced to map the classification information and similarity between spectrogram image features into the learned hash codes, thereby achieving the maximum class separability and maximal hash code discriminability during model training. Experimental results show that the efficient and compact binary hash codes generated by the proposed method has the recall, precision and F1 score of over 98.5% in speech retrieval. Compared with methods such as single-label retrieval method, the average running time of the proposed method using Log-Mel spectra as features is shorted by 19.0% to 55.5%. Therefore, this method can improve the retrieval efficiency and retrieval precision significantly while reducing the amount of computation.
In multi-controller Software Defined Network (SDN), since the existed switch migration strategies always have low efficiency and need to migrate many times which only consider single migration factor, a mechanism of switches migration based on progressive auction named PASMM (Progressive Auction based Switches Migration Mechanism) was proposed. To improve network benefit, the switch migration problem was optimized by auctioning controllers' remaining resources in the mechanism. By increasing the trading price of the over-demanded controllers' resources, PASMM completed the auction and redeployed the controllers and switches. The simulation results show that, compared with some typical switch migration policies, PASMM achieves good load balancing of controllers, reduces the response time of the PACKET_IN messages by an average of 13.5%, and spends the least migration time with the increasing of switches flow requests.
The vertex shader needs an extra generating pattern and the calculation of subdivision level is complicated when subdividing terrain grid. A Level of Detail (LOD) terrain rendering algorithm using subdivision shader was put forward for the insufficiency. The proposed method used block quad tree organization to build a rough terrain grid hierarchical structure, and filtrated the activity terrain blocks by LOD discrimination function. A subdivision factor calculation method was proposed based on viewpoint in a three-dimensional continuous distance in tessellation control shader and cracks of the external factor segment was eliminated. As a result, displacement mapping on tessellation evaluation shader and displacement of height component in fine grid blocks were achieved. Meanwhile, the quadtree was saved to vertex buffer, and the exchange of resource between Central Processing Unit (CPU) and Graphic Processing Unit (GPU) was decreased. The subdivision process was accelerated by bringing in subdivision queue. The experimental results show that the proposed algorithm has a smooth detail level transition and good subdivision effect, and it can increase the utilization ratio of GPU and terrain rendering efficiency.
In order to solve the problem that deep learning ignores the local structure features of faces when it extracts face feature in face recognition, a novel face recognition approach which combines block Local Binary Pattern (LBP) and deep learning was presented. At first, LBP features were extracted from different blocks of a face image, which were connected together to serve as the texture description for the whole face. Then, the LBP feature was input to a Deep Belif Network (DBN), which was trained level by level to obtain classification capability. At last, the trained DBN was used to recognize unseen face samples. On ORL, YALE and FERET face databases, the experimental results show that the proposed method has a better recognition performance compared with Support Vector Machine (SVM) in small sample face recognition.
In order to reveal the evolution rules of supply chain network with the core of manufacturers, a kind of five-level local world network model was put forward. This model used the BA model and the multi-local world theory as the foundation, combined with the reality of network node generation and exit mechanism. First of all, the intrinsic characteristics and evolution mechanism of network were studied. Secondly, the topology structure and evolution rules of the network were analyzed, and the simulation model was established. Finally, the changes of network characteristic parameters were simulated and analyzed in different time step and different critical conditions, including nodes number, clustering coefficient and degree distribution, then the evolution law of the network was derived. The simulation results show that the supply chain network with the core of manufacturers has the characteristics of scale-free and high concentration. With the increase of time and the growth rate of the network nodes, the degree distribution of overall network approaches to the power-law distribution with the exponent three. The degree distribution of the network at all levels is different, sub-tier suppliers and retailers obey power-law distribution, suppliers and distributors obey exponential distribution, manufacturers generally obey the Poisson distribution.
Aiming at efficient data acquisition, real-time precise positioning and attitude measurement problems of geostress low-frequency electromagnetic monitoring, real-time data acquisition system was designed and implemented in combination with positioning and attitude measurement module. The hardware system took ARM microprocessor (S3C6410) as control core based on embedded Linux. The hardware and software design architecture were introduced in detail. In addition, the algorithm of positioning and attitude measurement characteristics data extraction was proposed. Monitoring terminal of data acquisition and processing was designed using Qt/Embedded GUI programming technique based on LCD (Liquid Crystal Display) and achieved human-computer interaction. Meanwhile, the required data could be real-time stored to SD card. The results of system debugging and actual field experiments indicate that the system can complete the positioning and attitude data acquisition and processing, effectively solve the problem of real-time positioning for in-situ monitoring. It also can realize geostress low-frequency electromagnetic monitoring with high-speed, real-time and high reliability.
Concerning the perspective of supply chain integration, a blood supply model was developed, which aimed to minimize the blood acquisition risk, system operation cost, the punishment for both excessive and insufficient acquisition by the multi-objective programming method. Taking into account the feature that the amount of expired blood is proportional to time, as well as the cost for expired blood processing, a regional supply and demand equilibrium model characterized by stochastic demand of the four types of blood was built. The model was proved to be convex, and the variational inequality of the blood supply and demand network equilibrium was derived. By modified quasi-Newton method, the solutions of the blood supply chain supply and demand equilibrium under stochastic demand condition were obtained. Finally, a case study in Chengdu verified the model's applicability.
The key issue of network virtualization is Virtual Network Embedding (VNE), and the rapid growth of energy cost makes infrastructure providers concern energy conservation. An energy conservation VNE algorithm that centrally used network topology for saving energy on VNE problem was presented. The importance of the nodes was characterized by the conception of closeness centrality and the capabilities of the nodes, and the working nodes were preferentially used for resources integration to reduce energy consumption and calculation cost, that ensured the distance of the substrate links won't be too long. The simulation results show that the proposed algorithm improves revenue-energy ratio more than 20% when accept ratio reaches 70% and revenue cost ratio reaches 75%, and has advantages compared with the previous algorithms.
Navigation exists potential safety hazard when autonomous mobile robot moves in dynamic uncertain environments. In order to improve the navigation safety, a representation method of navigation environments using time of contact was proposed, namely time of contact space. As risk index in navigation environments, the time of contact between two points of an arbitrary was computed by using linear velocity and rotation velocity, and the configuration space was mapped into time of contact space when robot moved in the navigation environment. The time of contact space was applied to classic behavior dynamic navigation method. Compared with the classical behavior dynamics method and behavior dynamics adding velocity obstacles, the simulation results prove that the time of contact space can guarantee safety navigation of autonomous mobile robot.