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1.
CAI Yunfei TANG Zhenmin ZHAO Chunxia 《电子学报:英文版》2014,(1):25-30
A new layered multi-robots architecture for cooperative online simultaneous localization and map- ping based on Service-oriented architecture (SOA) is pro- posed. This architecture is constructed by the concepts of service-oriented and loosely coupled center scheduling. These methods make robots' underlying function realiza- tion be transparent in cooperation and avoid the impact affected by robot heterogeneous characteristics, which will be beneficial to the system construction, expansion, re- structuring and maintenance. All data packages follow the SOA unified data format, which can avoid the impact af- fected by sensor heterogeneous characteristics. The point to point serving model reduces the path of data transmis- sion which can improve the timeliness of the system. All of these features can satisfy the requirements of multi-robots cooperative online SLAM. The simulation results show the feasibility, applicability and practicability of this architec- ture. 相似文献
2.
Thanks to the spread of the Internet, opportunities to use online bookstores have been increasing in recent years. However, it is difficult for the typical customer to intuitively grasp which book sells well or which book is recommended by the shop. We have therefore developed a display system for virtual bookstores in which an image of books arranged in a bookshelf or stacked on a table is reproduced by using WebGL. Since the amount of book stock that is managed by the server side needs to be changed as orders come in from clients, we introduce a server side technology using a hypertext preprocessor (PHP). 相似文献
3.
基于XML网上书店系统的设计 总被引:2,自引:2,他引:0
XML是新一代网络数据表示、传递和交换的标准,是Internet环境中跨平台的、依赖于内容的技术。XML的新特性改变了人们在网络的交换方式,加速了电子商务的发展。网上书店系统体系结构采用B/S结构,MSVS2005作为B/S结构应用程序的开发工具。在开发中采用基于XML技术及MSSQLServer2005数据库技术,实现了用户登录注册、图书信息浏览、图书搜索、购物车、书籍管理、结账、生成订单等主要功能,使系统具有方便快捷、界面友好、可移植等特点。 相似文献
4.
Despite that existing data sharing systems in online social networks (OSNs) propose to encrypt data before sharing, the multiparty access control of encrypted data has become a challenging issue. In this paper, we propose a secure data sharing scheme in 0SNs based on ciphertext-policy attribute- based proxy re-encryption and secret sharing. In order to protect users' sensitive data, our scheme allows users to customize access policies of their data and then outsource encrypted data to the OSNs service provider. Our scheme presents a multiparty access control model, which enables the disseminator to update the access policy of ciphertext if their attributes satisfy the existing access policy. Further, we present a partial decryption construction in which the computation overhead of user is largely reduced by delegating most of the decryption operations to the OSNs service provider. We also provide checkability on the results returned from the OSNs service provider to guarantee the correctness of partial decrypted ciphertext. Moreover, our scheme presents an efficient attribute revocation method that achieves both forward and backward secrecy. The security and performance analysis results indicate that the proposed scheme is secure and efficient in OSNs. 相似文献
5.
随着Internet技术的快速发展,网上购物已成为人们生活方式中的重要选择。与传统购物相比,它具有选择面大、价格便宜、交易方便、节省时间等优势。由于M VC模式开发的系统具有可维护性、可扩展性、可移植性和组件可复用性等特点,越来越多的中小型电子商务网站开发都采用此模式。本系统采用M VC模式进行开发,具备完备的前、后台处理功能,能满足用户基本的网上购书需求。 相似文献
6.
This paper reports the physical realization of the Bipolar Field-Effect Transistor (BiFET) and its onetransistor basic building block circuits. Examples are given for the one and two MOS gates on thin and thick, pure and impure base, with electron and hole contacts, and the corresponding theoretical current-voltage characteristics previously computed by us, without generation-recombination-trapping-tunneling of electrons and holes. These examples include the one-MOS-gate on semi-infinite thick impure base transistor (the bulk transistor) and the impurethin-base Silicon-on-Insulator (SOI) transistor and the two-MOS-gates on thin base transistors (the FinFET and the Thin Film Transistor TFF). Figures are given with the cross-section views containing the electron and hole concentration and current density distributions and trajectories and the corresponding DC current-voltage characteristics. 相似文献
7.
Using the measured capacitance-voltage curves ofNi/Au Schottky contacts with different areas and the current-voltage characteristics for the A1GaAs/GaAs, A1GaN/A1N/GaN and InoAsA10.szN/A1N/GaN heterostructure field-effect transistors (HFETs) at low drain-source voltage, the two-dimensional electron gas (2DEG) electron mobility for the prepared HFETs was calculated and analyzed. It was found that there is an obvious difference for the variation trend of the mobility curves between the Ⅲ-V nitride HFETs and the A1GaAs/GaAs HFETs. In the III-V nitride HFETs, the variation trend for the curves of the 2DEG electron mobility with the gate bias is closely related to the ratio of the gate length to the drainto-source distance. While the ratio of the gate length to the drainto-source distance has no effect on the variation trend for the curves of the 2DEG electron mobility with the gate bias in the A1GaAs/GaAs HFETs. The reason is attributed to the polarization Coulomb field scattering in the Ⅲ-V nitride HFETs. 相似文献
8.
The 'abnormally' high electrical conductivity ofpure water was recently studied by us using our protonic bond, trap and energy band model, with five host particles: the positive and negative protons, and the amphoteric protonic trap in three charge states, positive, neutral and negative. Our second report described the electrical charge storage capacitance of pure and impure water. This third report presents the theory of particle density and electrical conductance of pure and impure water, including the impuritons, which consist of an impurity ion bonded to a proton, proton-hole or proton trap and which significantly affect impure waters' properties. 相似文献
9.
10.
SHAN Hangguan WANG Hao WANG Zongxin 《电子学报:英文版》2008,(2):381-385
An amplify-and-forward multicarrier cooperative system was proposed in this paper. The optimal resource-allocation problem was investigated in terms of improving data rate. An effective resource-allocation algorithm was proposed based on three techniques, adaptive modulation, subchannel reassignment design and transmit power adaptation. The designed subchannel reassignment not only increases the average data rate, but also raises the threshold of "water-filling" in optimizing power allocation that can further increase data rate. Since the power allocation is based on the designed subchannel reassignment, the complexity of the proposed algorithm is reduced greatly. Simulation results show that the proposed algorithm effectively increases the system's average data rate. 相似文献
11.
LI Ning CAO Zhen DENG Zhongliang 《电子学报:英文版》2014,(3):516-520
The localization of satellite interference sources under the condition of low SNR has been a hot research topic at current, where the signal de-noising is important in the following positioning work. With the help of the wavelet analysis theory, this paper proposes a denoising algorithm based on the wavelet coefficients in low SNR. After correcting and reconstructing the signal by the correction coefficients, we could obtain the SNR and Root mean square error (RMSE), and then we could correct the signal for the second time. The simulation results show that this de-noising algorithm can effectively remove the noise of the signal in low SNR, which would have a good effect on the estimation of time delay parameter in the localization of satellite interference sources. 相似文献
12.
WANG Wei HE Weiping LEI Lei GUO Gaifang 《电子学报:英文版》2014,(3):550-556
In this paper we present a method for extracting the best candidate edge combination based on multi-features fusion, aiming at the challenges of accurately locating the DataMatrix (DM) code (hereinafter referred to as DM code) with pollution and perspective deformation. Firstly, DM code edges are transformed from image into Hough domain in which linear feature is more prominent. We are able to obtain the valid combinations of candidate marginal points after prior rules-based filtering. Then, we design and extract four boundary features of the finder pattern in image domain. Meanwhile, we establish the model of distorted DM code edge distribution in Hough domain and extract the corresponding features. Finally, we merge the multi-features according to the D- S theory and make the final locating based on the fusion result. Compared with traditional methods, the experiments demonstrate the greater robustness and flexibility of our proposed approach to accurately detecting the contaminated Data Matrix coexisted with perspective deformation. 相似文献
13.
In this paper's simple upper bounds are derived on the frame and bit error probabilities of binary linear codes over Additive white Gaussian noise (AWGN) channels. The conventional union bound is first truncated and then amended, which can be justified by invoking Gallager's first bounding technique (GFBT). Different from most other works, the "good region" is specified by a suboptimal list decoding algorithm. The error probability caused by the good region can be upper-bounded by the union bounds using pair-wlse error probability and tripletwise error probability, which can be further tightened by exploiting the independence between the error events and certain components of the receiving signal vector. The proposed bounds are simple since they involve only the Q-function. The proposed bounds improve our recently proposed bounds. Numerical results are also presented to compare the proposed bounds with the Divsalar bound, which is a simple tight upper bound with closed-form, and the Tangential-sphere bound (TSB), which is considered as one of the tightest upper bounds. 相似文献
14.
DRA (Dynamic resolution adaptation) audio coding standard was shown to deploy transientlocalized MDCT to effectively suppress pre-echo artifacts and statistic allocation of codebooks to improve the compression efficiency of Huffman coding. Its quantizers and Huffman codebooks are designed in such a way that a signal path of 24 bits is provided throughout the codec so that high audio quality can be delivered if bit rate suffices. Although simple, it delivers state-of-the-arts compression efficiency as shown by five rounds of ITU-R BS.11116 compliant subjective listening tests. 相似文献
15.
At present the video sharing service has gradually became one of the Internet killer applications. It is crucial to the service providers that understand the intrinsic nature of Sharing video relationshlp-networks (SVRNs) formed by video related list. This paper investigates the relationships between sharing videos using complex networks theory. New metrics are introduced to model and characterize the SVRN from topological view. Through extensive study on YouTub% a set of key findings are revealed. The results show that the node in- degree of SVRNs follows the power-law distribution and its entropy remains stable over time. The topology also exhibits an assortative property and obvious clustering phenomenon. But the rich-club phenomenon is not evident compared with the Internet AS-level topology. This research will enable the service providers to optimally plan and operate their video-based services. 相似文献
16.
ZHOU Dong LIU Jianxun ZHANG Sanrong 《电子学报:英文版》2014,(3):480-483
One of the defining challenges in patent prior-art search is the problem of representing a long, technical document as a query. Previously work on this problem has concentrated on single query representations of the patent application. In the following paper, we describe an approach which uses multiple query representations generated from semantically coherent passages extracted from patent documents. We validate our technique in an experiment using the CLEF-IP 2011 patent search collection. Our system achieves statistically significant improvements over various state-of-art query generation techniques. 相似文献
17.
Aiming at detecting Cl2 gas, this study was made on how to make In-based compound semiconductor oxide gas sensor. The micro-property and sensitivity of In-based gas sensing material were analyzed and its gas sensitive mechanism was also discussed. Adopting constant temperature chemical coprecipitation, the compound oxides such as In-Nb, In-Cd and In-Mg were synthesized, respectively. The products were sintered at 600 ℃ and characterized by the Scanning Electron Microscope (SEM), showing the grain size almost about 50-60 nm. The test results show that the sensitivities of In-Nb, In-Cd and In-Mg materials under the concentration of 50 × 10^-6 in Cl2 gas are above 100 times, 4 times and 10 times, respectively. The response time of In-Nb, In-Cd and In-Mg materials is about 30, 60 and 30 s, and the recovery time less than 2, 10 and 2 min, respectively. Among them, the In-Nb material was found to have a relatively high conductivity and ideal sensitivity to Cl2 gas, which showed rather good selectivity and stability, and could detect the minimum concentration of 0.5 × 10^-6 with the sensitivity of 2.2, and the upper limit concentration of 500 × 10^-6. The power loss of the device is around 220 mW under the heating voltage of 3 V. 相似文献
18.
WANG Xuesong CAO Ge CHENG Yuhu 《电子学报:英文版》2014,(4):718-722
In order to realize automatic region matching between source and target images, a multi-source local color transfer algorithm based on texture similarity is proposed. The source and target images are segmented into a set of regions using an image segmentation algorithm. It computes the texture features of each region through the gray level co-occurrence matrix and then constructs corresponding texture feature vectors. The authors measure the relevance between the target and source regions by computing the Euclidean distance between corresponding tex- ture feature vectors. The source region having the largest relevance with the target region is selected as the transfer source. Complete the color transfer by performing color space transformation and linear conversion on color values. Experimental results concerning on multi-source local color transfer and gray image colorization verify the validity of the proposed algorithm. 相似文献
19.
The Online social networks (OSNs) offer attractive means for social interactions and data sharing, but also raise a number of security and privacy issues. Since the OSNs service provider is always semi-trusted, current solutions propose to encrypt data before sharing. However, data encryption causes a lot of inconveniences and large overheads for data dissemination and data retrieval. In this paper, we propose a secure data sharing and retrieval scheme in cloud-based OSNs. Based on ciphertext-policy attribute-based encryption, our scheme achieves multi- party access control, which allows data owners to outsource encrypted data to the OSNs service provider for sharing, and enables data disseminators to disseminate the data owners' data by customizing new access policy. Our scheme also provides searchable encryptlon scheme to support fast searches in massive amount of encrypted data from both data owners and data disseminators. Further, our scheme preserves the privacy of data owners and data retrievers during the data sharing and retrieval processes. In addition, the computation overhead of data retrievers is reduced by delegating most of the decryption operations to the OSNs service provider. The security and performance analysis results indicate that our scheme is secure and privacy-preserving. 相似文献
20.
SHANG Xiaopu ZHANG Runtong LI Xiaolong 《电子学报:英文版》2014,(4):805-809
This paper proposes an intra-PAN mobility management scheme for IPv6 over Low-power wireless personal area networks (6LoWPAN) on the basis of "networkbased" idea. We developed a tree-like network architecture which includes coordinate nodes for packet routing. All of the control messages are designed to transmit in link layer, and the sensor nodes are free to consider care-of address and the mobile nodes are unnecessary to deal with any mobility handoff messages. The simulation results show that this scheme efficiently cuts down the signaling cost and reduces the energy consumed by fixed nodes which can extend the life time of the whole Personal area networks (PAN). 相似文献