20 May 2011, Volume 37 Issue 10
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Computer Engineering. 2011, 37(10): 1-7. https://doi.org/10.3969/j.issn.1000-3428.2011.10.001
Different applications have different security sensitivities, which are determined by subjective judgment in the process of security research on Internet of Things(IOT). This paper presents a Security Model of IOT Based on Hierarchy(BHSM-IOT), which can be used to analyze the topology structure, predict the attack source and attack type and determine the application level of security domain, so that appropriate safety technical configuration can be made. The model is applied in a wisdom campus system of a university, and result proves that it is helpful for the managers to construct a more safe and stability system for the students and teachers with the model.
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Computer Engineering. 2011, 37(10): 8-10. https://doi.org/10.3969/j.issn.1000-3428.2011.10.002This paper proposes a strategy which generates a codebook for each class. When the classifier between any two classes is trained, only the image vectors generated from the codebooks related to these two classes are considered. Compared with the traditional method using one universal codebook, the dimension of image vectors is greatly reduced while the diversity of them is preserved in the approach, which avoids the occurrence of the curse of dimensionality. Experimental results show that the approach can gain better results than traditional methods which use only one codebook.
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Computer Engineering. 2011, 37(10): 11-13. https://doi.org/imagepyramid;spatialindex;linearquadtree;neighbors-searchingBased on linear quadtree, a spatial image retrieval algorithm of image pyramid is proposed. According to the topological relations of linear quadtree, this paper designs an encoding method with the characteristics of direction coherence, progressive hierarchy; establishes a mapping between image pyramid and linear quadtree; gives a neighbors-searching algorithm in accordance with the natural growth of longitude-latitude; and constructs a global multi-resolution virtual terrain environment to test the encoding method and algorithm. Experimental results show that the algorithm can significantly reduce the time cost of spatial image retrieval, and has a high encoding efficiency and neighbors searching efficiency.
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Computer Engineering. 2011, 37(10): 14-15. https://doi.org/10.3969/j.issn.1000-3428.2011.10.004A Directional Filter Bank(DFB) containing eight directional filter masks is proposed. The filter coefficients which probably go beyond the range of the horizontally oriented mask are assigned zero value, a section of Fibonacci sequence based on the golden segmentation ratio is chosen as the other mask coefficients according to the rule of gradually decrease by the center to peripheral. The other seven masks are rotated from the horizontally oriented mask. The especial structure can ensure the consistency of all the filter masks’ structure. This DFB not only solves the overflow problem of filter masks, but also ensures the coefficients on the rotated masks distribute more regularly. The performance of this DFB is evaluated with some typical low quality images of FVC database. Experimental results show that the proposed DFB has dramatic effect to low quality fingerprint images, it can connect the broken fingerprint and enhance the ridges more efficiently.
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Computer Engineering. 2011, 37(10): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2011.10.005It is difficult to dig out the relevant hidden earthquake region because of the high complexity and non-linear relationship in seismic activity. To solve this problem, a new method is used to study the seismic trend combining time sequence similarity matching with Extreme Value Theory(EVT), including morphology-based time sequence-earthquake magnitude Two-Dimensional(2D) similarity matching and statistical research by applying EVT. Some correlation between the regions is verified according to those methods. The effectiveness of the method is verified and the judgment is made by applying it in the historical data.
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Computer Engineering. 2011, 37(10): 19-22. https://doi.org/10.3969/j.issn.1000-3428.2011.10.006A Track Before Detection(TBD) method based on marginalized particle filter is proposed for the single-frame low Signal to Noise Ratio (SNR) infrared small target detection and tracking in infrared detection system. Under the idea of mixture state filter, the method is directly used on the original image data. The number of continue probability density particles and new birth probability density particles are deterministic and the probability of the existence of the target is derived. Linear variables disappeared in the measurement equation are marginalized and updated by Kalman filter. Experimental results prove that this method can effectively reduce the root mean square error of target tracking and improve target detection rate, especially for low SNR target.
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Computer Engineering. 2011, 37(10): 23-25. https://doi.org/10.3969/j.issn.1000-3428.2011.10.007
For the requirement of reliable communication and efficiency of Computer Numerical Control(CNC) system to field-bus, this paper analyzes the efficiency of traditional field-bus and its causation, and designs a high efficiency and reliable communication mechanism based on hardware link layer retry. Mechanism is successfully used into CNC system, it eliminates layer protocol transform and interrupt delay of operating system. Experimental results show that the mechanism has high efficiency and real-time, it can meet the requirement of CNC system application.
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Computer Engineering. 2011, 37(10): 26-28. https://doi.org/10.3969/j.issn.1000-3428.2011.10.008Integrating RFID security and RFID anti-collision are research hotspots of RFID technology in the Internet of things. Its shortcoming is them being resolved as two different parts. This paper attempts to deal with them as a whole, with a strategy integrating lightweight random key double-authentication and dynamic slot-ALOHA protocol. The processing mechanism and performance comparison are given in this paper. The new mechanism not only maintains the advantage of rapid tag identification, but also has the ability to resist re-transmission attack, tracking-attack, blocking-attack, tampering-attack and so on. It has a high safety and practicality.
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Computer Engineering. 2011, 37(10): 29-31. https://doi.org/10.3969/j.issn.1000-3428.2011.10.009
To solve the problems that exitst in computational model of space-based visual attention, a computational model for object-based visual attention using spatial visual saliency is proposed in this paper. Edges are extracted from the input image and salient edges are obtained according to the edge saliency. Then these salient edges are organized to get the boundary of the perceptual objects. Attention value of each perceptual object is computed according to the area, location and saliency. Focus of attention is shifted among these perceptual objects in terms of the attention value. The proposed model is tested on many natural images. Experimental results show that the proposed model is valid and the attention results are consistent with human visual system.
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Computer Engineering. 2011, 37(10): 32-34. https://doi.org/10.3969/j.issn.1000-3428.2011.10.010The up-to-date algorithms on delay tomography are based on the discrete delay mode, but it is low efficiency in this mode. This paper proposes a continuous delay mode, whose delay is distributed on a function with some parameters. According to the rule of multicast and based on end-to-end moments, the parameters can be estimated using nonlinear least squares and the best step is chosen by the one-dimension Newton search in iteration. Experimental results on Matlab and NS2 simulation show that the algorithm needs little storage and is simple with high efficiency.
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Computer Engineering. 2011, 37(10): 35-37. https://doi.org/10.3969/j.issn.1000-3428.2011.10.011
Aiming at that the boundaries of time series exists uncertainty when clustering, this paper presents a method of soften boundaries. In order to form sub-series, the values of multivariate time series are put into recordset’s attributes and windows of given width are slided through the attributes. The sub-series are normalized with a simple method and then clustered with fuzzy logic so as to obtain its delegates with soften boundaries. Rule’s support and confidence are calculated with membership so as to make the two important measures more exact. Good rules are selected with J-measure which is based on membership. Empirical results show that the patterns and rules are meaningful and resultful.
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Computer Engineering. 2011, 37(10): 38-40. https://doi.org/10.3969/j.issn.1000-3428.2011.10.012
This paper studies on the dangerous edge that presents in the Mod-dejavoo algorithm. It points out that the location and the role of the dangerous edge, by comparing the control-flow graphs around the program changed, analysing the characteristics of Java. It also points out the dangerous edge does not occur uniquely. It proposes a method to find the location and quantity based on the Mod-dejavoo algorithm, which generates regression test set effectively. The research provides test set screening with a new method.
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Computer Engineering. 2011, 37(10): 41-43. https://doi.org/10.3969/j.issn.1000-3428.2011.10.013According to the characteristics of a lot of words co-occurrence in mass data of Short Messaging Service(SMS), a context-based SMS text classification method based on the context term is defined word similarity relations, and defines the term weights using context, which expresses more scientific terms in this category in the semantic representation and thus further improves classification efficiency of SMS text. Experimental results show that the classification performance of method than the traditional simple vector distance classification is significantly improved.
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Computer Engineering. 2011, 37(10): 44-46. https://doi.org/10.3969/j.issn.1000-3428.2011.10.014
The paper introduces the pre-processing procedure, which includes data cleaning, Website topology identification, user identification, session identification, page filtering and path completion. With respect to logs without reference record, a path completion algorithm based on Website topology is put forward and implemented. A multi-factor user similarity computing method is introduced and applies on Web user clustering. Davies-Bouldin index is used to evaluate to effectiveness of the experiment results.
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Computer Engineering. 2011, 37(10): 47-49. https://doi.org/10.3969/j.issn.1000-3428.2011.10.015In order to improve the accuracy of sentence similarity from structures similarity, this paper proposes a similarity measure method of Chinese sentence structures. It performs the optimal matching between the Part Of Speech(POS) sequences and POS dependency of two compared sentences. Experimental results show that the new method works well and it is more reasonable than the other methods.
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Computer Engineering. 2011, 37(10): 50-51. https://doi.org/10.3969/j.issn.1000-3428.2011.10.016
Collaborative filtering is one of the most widely used algorithms in the personalized recommendation system. With the increase in the number of users and items, the data sparsity becomes the important factor which affects the quality of the personalized recommendation. To address this issue, a new collaborative filtering algorithm based on the similarity propagation is introduced. The similarity between users can propagate in a limited path length as long as the similarity greater than the threshold. So the number of the nearest neighbors which is used to prediction increases and the quality of the recommendation improved because of the relief of the data sparsity.
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Computer Engineering. 2011, 37(10): 52-54. https://doi.org/10.3969/j.issn.1000-3428.2011.10.017The traditional Kernel Principal Component Analysis(KPCA) method maps original data into high dimensional space via the implicit mappings with real-valued function, such a mapping needs too much time for finding the hyper-plane in the classification assignments as well as leads to lower classification accuracy. Aiming at this problem, this paper maps the input into Reproducing Kernel Hilbert Spaces(RKHS) which are full with continuous values function by the explicit mappings, and then implements dimensionality reduction in RKHS. Experimental results in real text data show the proposed method outperforms the comparison in terms of classification accuracy and running time.
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Computer Engineering. 2011, 37(10): 55-57. https://doi.org/10.3969/j.issn.1000-3428.2011.10.018By analyzing the dominant constraints and connectivity constraints of connected dominating set, two reduction rules for minimum connected dominating set in simple connected graph is proposed. These rules can find out some required nodes and delete some redundant nodes in advance through classification of neighbors of any node, and through finding cut nodes in graph, thus reducing the size of the original problem. These reduction rules are proved theoretically and tested by random simulations.
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Computer Engineering. 2011, 37(10): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2011.10.019This paper studies the algorithm for detecting community structure of complex network based on clustering, analyzes the similarity measure method between vertices. It proposes Mapping Vertex into Vector(MVV) algorithm, which converts all vertices in network into vectors. It converts the nodes into the data structure suitable for clustering algorithms. It compares the different clustering algorithms and similarity measure method, the results show that MVV algorithm can improve the ability of detecting complex networks community.
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Computer Engineering. 2011, 37(10): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2011.10.020In the core computing algorithms based on the discernibility matrix idea, there are lots of empty and repeat elements in the discernibility matrix, and these elements cost a mass of memory space and waste plenty of computing time during computing core. In order to solve the problem, by considering frequent pattern tree, this paper proposes a novel data structure named C_Tree, and a quick and efficient core computing algorithm is designed based on C_tree. Theory Analysis and example results show that time complexity and space complexity of the algorithm depend on simplifying the decision table and constructing time and space complexity of the C_Tree, which improves the efficiency of computing core.
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Computer Engineering. 2011, 37(10): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2011.10.021Aiming at Liner-structured Composed Routing Problem(LCRP) based on Service Overlay Network(SON), this paper takes load balance as optimal goal and takes function and multi-QoS constraints of user requests as constraint conditions to construct optimal model. The layered method and improved ants algorithm named AA_LCRP are adopted to solve the problem. Simulation result proves that the success rate of service composition is higher and path length is shorter by using the model, and AA_LCRP has good performance.
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Computer Engineering. 2011, 37(10): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2011.10.022Aiming at the problem that the current computation method of Prolate Spheroidal Wave Function(PSWF) is inefficient and intuitive in simulation, this paper constructs a PSWF generator in Simulink according to the differential equation definition of PSWF. The design method for bandpass PSWF with notch depth is given. To take Federal Communications Commission(FCC) spectral mask and narrowband interference into account, different pulses are generated by the Simulink method. The results show that the designed PSWF can meet FCC requirements and achieve variable notch depth at an arbitrary frequency.
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Computer Engineering. 2011, 37(10): 70-72. https://doi.org/10.3969/j.issn.1000-3428.2011.10.023In order to improve the end-to-end lifetime of paths in Vehicular Ad Hoc Networks(VANET), this paper proposes a route planning algorithm named LGGR based on high-reliable beam path. Every node in an intersection learns if it is connected with those nodes in a neighbored intersection by disseminating connectivity information. The degree of intersections and lifetime and self-heal time of route segments are considered as key measurements to select forward nodes. The forward node with high network connectivity and long path lifetime is selected, and a high- reliable beam path is formed after a lot of route decisions. Simulation results reveal that LGGR outperforms traditional algorithms, such as AODV, GPSR.
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Computer Engineering. 2011, 37(10): 73-75. https://doi.org/10.3969/j.issn.1000-3428.2011.10.024
Aiming at traditional LT code has the drawbacks of coding efficiency is not high, decoding time is long and decoding probability is low, this paper designs a system of Variable Frame Length(VFL) LT code in Wireless Sensor Network(WSN), takes the measure of frame length design, splits the source data and encodes them separately to meet requirement of accuracy and efficiency of data in networks and unequal protection requirements. Experimental results show that VFLLT system can effectively improve the coding efficiency, the decoding and recovery probability in WSN, and enhance the feasibility of LT code in actual system.
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Computer Engineering. 2011, 37(10): 76-78. https://doi.org/10.3969/j.issn.1000-3428.2011.10.025This paper presents a multi-relay Amplification Forwarding(AF) cooperative node selection algorithm based on Residual Power(RP), which jointly considers the Channel State Information(CSI) and the residual energy information of nodes to optimize the network lifetime, uses the weighting function and the channel capacity gain threshold to select the relay set. Simulation results show that both dynamic relay power distribution and fixed relay power distribution, performance reached the best while selecting the 3~4 relays. Relative to only considering the CSI node selection algorithm, this algorithm is able to extend network lifetime up to 82% under dynamic relay power distribution and 4 relay numbers.
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Computer Engineering. 2011, 37(10): 79-80. https://doi.org/10.3969/j.issn.1000-3428.2011.10.026
From the angle whether maintaining flow state information, this paper presents an improved Active Queue Management(AQM)——Single Flow-AQM(SF-AQM). SF-AQM only maintenances data flow state information which has high transmission rate in order to reduce the router overhead identifies the non-adaptive flow by comparing packet the arrival intervals of different flow, improves the fairness of the algorithm, and controls the queue length under the target value to ensure the stability of the algorithm. Simulation results show SF-AQM algorithm has good performance in fairness and stability, and it is an effective algorithm in high performance communication networks congestion control.
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Computer Engineering. 2011, 37(10): 81-83. https://doi.org/10.3969/j.issn.1000-3428.2011.10.027Parallel Decodable Turbo Codes(PDTC) increases data throughput, while reduces the decoding performance. This paper analyzes the collision free interleaving condition in PDTC, introduces row column random interleaver and improves it, uses S-random regulation into interleaving, makes the same column(row) position data distance increase to S at least after interleaving. The contrast simulation to row column random interleaver shows that the improved design scheme can raise the data dispersion, enlarge the neighboring data distance in every processor, make the lower code weight better, and increase the bit error rate performance.
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Computer Engineering. 2011, 37(10): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2011.10.028Blue is a typical active management algorithm, but it suffers from queue size oscillations and delay oscillations, particularly the number of connections is so large or number of connections changes so suddenly that causes queue overflow or empty. Aiming at this problem, this paper proposes an adaptive active queue management algorithm——ABlue(Adaptive Blue), in order to stabilize the queue length and delay jitter, and reduce the packet loss rate according to the dynamic calculation of network flow changes mark probability. Simulation results show that ABlue algorithm significantly reduces the packet loss rate of Blue algorithm, and performs slightly better than Blue in terms of link utilization.
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Computer Engineering. 2011, 37(10): 87-89. https://doi.org/10.3969/j.issn.1000-3428.2011.10.029Aiming at a large number of RREQ packet flooding problems in the route discovery process, an advanced AODVjr algorithm resulting from node energy and Cluster-Tree algorithm is proposed. The new AODVjr algorithm tries to avoid the low-energy nodes when choosing route and can control the general direction and hops of the RREQ packet. At the same time, the simulation results indicate that the new AODVjr algorithm can cut down the total energy cost effectively, share the network load properly, reduce the death of nodes, and extend the network life cycle.
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Computer Engineering. 2011, 37(10): 90-92. https://doi.org/10.3969/j.issn.1000-3428.2011.10.030Aiming at the problem of non-reasonable flow distribution in application layer of DTBF dynamic token distribution based on Best-effect, an improved DTBF+ algorithm of DTBF with link application behavior preference classification mechanism is proposed, which is based on user transfer content classification mechanism. The algorithm allocats excess token of idle user’s links dynamically to heavy user’s links of non- Peer-to-Peer(P2P) application. It can improve bandwidth utilization effectively and reduce the blindness of allocating resource through application test in the actual environment, the algorithm effect obviously on improving the instantaneous utilization bandwidth of non-P2P application links.
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Computer Engineering. 2011, 37(10): 93-95. https://doi.org/10.3969/j.issn.1000-3428.2011.10.031
In view of the irrelativeness between virtual channel scheduling and buffer management of current satellite networks, a new scheduling algorithm of Buffer Utilization rate Detection(BUD) is proposed. The algorithm analyzes the buffer utilization rate and the urgent degree thoroughly and then schedules the Virtual Channel(VC) which is corresponded to the scheduling function. It uses the OPNET to simulate and contrast the new scheduling algorithm, and results indicate that it is effective to decline the loss of data and delay, and the “starvation” phenomena caused by the unfairness of low priority service can be avoided under the premise of guaranteeing the throughput.
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Computer Engineering. 2011, 37(10): 96-98. https://doi.org/10.3969/j.issn.1000-3428.2011.10.032Based on the study of the existed unstructured Peer-to-Peer(P2P) network, this paper structures a three-tier mixed P2P model which combine P2P with the method of humans searching resource. In the model, peers with the same IPv6 network prefix compose a domain, peers with the same property compose groups in every domain, Intelligence Peer(IP) manages terminal peers in every group, routing peer is responsible for query routing between domains. Simulation result shows the model can enhance resource search efficiency, shorten search delay and reduce routing hops.
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Computer Engineering. 2011, 37(10): 99-101. https://doi.org/10.3969/j.issn.1000-3428.2011.10.033In the real world, the nodes in Wireless Sensor Networks(WSN) are often deployed in 3D scenario, e.g., deep sea, hill or forest, etc., therefore the information of three-dimensional localization should be provided for those nodes. A range-based localization algorithm for 3D WSN is proposed. This algorithm bases TDOA(Time Difference of Arrival) and gains the range between all of those nodes, moreover, it sets the weight as one when the range between the single-hop neighbor nodes is not greater than the communication radius, and the rest is zero. This algorithm bases the method of matrix iterative optimization and obtains the accurate position for the unknown nodes. Simulation result indicates that the localization accuracy of the localization algorithm is excellent.
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Computer Engineering. 2011, 37(10): 102-104. https://doi.org/10.3969/j.issn.1000-3428.2011.10.034
This paper presents a network flow inspection method which combines Deep Packet Inspection(DPI) with Deep Flow Inspection(DFI). DPI fulfills the target of fine-grained at the use of Pattern Match Engine(PME) of the network processor MPC8572. DFI is to notify the underlying false detection that can be caused by DPI and to request for re-detecting. Experimental results show that joint method has the ability of inspection wrong and error correction, and it can improve the accuracy of inspection.
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Computer Engineering. 2011, 37(10): 105-107. https://doi.org/10.3969/j.issn.1000-3428.2011.10.035This paper proposes an improved coarse timing synchronization method by altering the structure of training symbols and selecting special training sequences. The improved coarse synchronization algorithm is applied to Single Carrier Frequency Domain Equalization(SC-FDE) system in aeronautical channel of different scenarios. Simulation results show that the proposed method solves the problem about the plateau of timing metric in traditional coarse synchronization algorithm——Schmidl & Cox algorithm, and the mean of timing estimation offset is close to zero. This method gains better effect and accuracy of timing synchronization.
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Computer Engineering. 2011, 37(10): 108-110. https://doi.org/10.3969/j.issn.1000-3428.2011.10.036Virtual machine, instead of the local terminal, communicates with application server in virtual environment. However, the virtual hardware may not support the interface of the cryptographic device when virtual machine uses the local cryptographic device. This paper proposes to develop Virtual Cryptographic Device System(VCDS) as the intermediate party, which combines the real cryptographic device plugged into the local terminal and the application layer of virtual terminal. It describes the designs of the core modules, as well as the implementations of VCDS, and analyzes its security. This system helps to ensure the transparency when virtual terminal using local real cryptographic device, and provides a good service of encryption, authentication and so on.
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Computer Engineering. 2011, 37(10): 111-113. https://doi.org/bt_ssl5211476@sina.comAccording to the features that the attacker usual depends on modifying function return address or function entry address to change the program execution sequence and the structural characteristics of ELF file, while calling function and returning after function calling, certain specific information is dealed with in order to detect attack action. This paper presents a new approach of detecting buffer overflow attacks at runtime depending on the pin that is a tool for the dynamic program monitoring and provides numbers of API functions to design a tool which executives runtime program. Case analysis shows that the method does not need alter the software and hardware system.
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Computer Engineering. 2011, 37(10): 114-116. https://doi.org/10.3969/j.issn.1000-3428.2011.10.038The new encryption algorithm for digital color image is proposed. The image can be encrypted through encryption matrixes generated with Logistic chaotic sequences to eXclusive OR(XOR) color matrixes many times. The R, G and B components of the color image can be treated randomly and encrypted image becomes more uniform. Because the chaotic sequences are extremely sensitive to the parameters and the initial values, even if the encryption algorithm is open. Without the right key, the useful information can not be got. The encryption key length is effectively enlarged by using multiple sets of parameter of the branch and initial value as the encryption key. The experiments confirm its validity.
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Computer Engineering. 2011, 37(10): 117-119. https://doi.org/10.3969/j.issn.1000-3428.2011.10.039
The secret information is embedded in one of elements of every 8×8 Discrete Cosine Transform(DCT) coefficient matrixes of cover image, and based on DCT characteristic the stego-image is correspondingly changed according to different embedded locations, which can improve imperceptibility of Spread Spectrum(SS) algorithm. Simulation results indicate that the SS algorithm based on DCT characteristic can improve Peak Signal to Noise Ratio(PSNR) of stego-image not by reduction of embedment strength, thus avoids the problem that reduction of embedment strength enlarges retrieval errors. In order to effectively overcome the adverse effect of round error and raise accuracy rating, a fault-tolerant retrieval algorithm is proposed according to the probability density function of retrieval errors. Simulation results verify the feasibility and validity of the algorithm.
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Computer Engineering. 2011, 37(10): 120-122. https://doi.org/xuning1979@126.comThis paper analyzes the application of SELinux on the current Linux type operating systems, introduces the definition of new identifier for the privileged user based on Role Based Access Control(RBAC) module and trusted computing, and propose a new privileged user management based on this definition for the secure Linux operating system. To solve the problem of distinguishing privileged users through UID with the role, it enhances the security of authentication strength by trusted computing’s password service, solves the problem of security mode switching by kernel enhancement, and effectively improves the secure application of SELinux in Linux system.
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Computer Engineering. 2011, 37(10): 123-124. https://doi.org/10.3969/j.issn.1000-3428.2011.10.041The validity of digital certificate depends on the digital signatures. To ensure the validity of digital signatures, a digital signature scheme with intrusion-tolerance private key is proposed. The Certificate Authority(CA) private key is generated using the RSA algorithm to ensure its un-forged. CA private key is shared based on the new (t, n) secret sharing mechanism. It uses its identification as a share of the private key. Furthermore, it is no need to reconstruct the CA private key to sign, so it enhances the security of CA private key. Theoretical analysis and experimental results show the effectiveness of the scheme.
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Computer Engineering. 2011, 37(10): 125-127. https://doi.org/10.3969/j.issn.1000-3428.2011.10.042To overcome the limitations of existing brute forcer for wpa/wpa2-psk based on single core CPU, a new high-speed brute forcer for wpa/wpa2-psk based on distributed multi-core CPU and Graphics Processing Unit(GPU) is proposed. Wherein, the PSK list is distributed to each PC reasonably using distributed technology. Multiple computing cores are made up of multi-core CPU and GPU on single PC to crack in parallel. GPU contributes to the cracking speed improvement due to its strong computing power of processing computation-intensive parallel tasks. Experimental results and reasonable estimations show that compared with traditional brute forcer, this new high speed brute forcer improves the cracking speed of wpa/wpa2-psk notably.
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Computer Engineering. 2011, 37(10): 128-130. https://doi.org/10.3969/j.issn.1000-3428.2011.10.043Peers in social network are divided into active nodes and inactive nodes after analyzing the features of social network. Mathematical model is built through analyzing the impact factors on XSS worms propagation. Simulations show that the impact of visit bias probability of nodes is small. The proficiency of social engineering used by XSS worms and the security consciousness of nodes can have a great impact on XSS worms propagation. Furthermore, the security consciousness of active nodes is very important and the strategy that active nodes are used as defensive points and monitoring points is feasible to defend against XSS worms.
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Computer Engineering. 2011, 37(10): 131-133. https://doi.org/10.3969/j.issn.1000-3428.2011.10.044
According to the possibility that an attacker can be detected during a network attack, an attack graph is transferred into a Petri Net, which is then expanded into an Expanded Petri Net(EPN). Attack costs of places are used to solve the optimum attach path and the total attack cost of an network attack; the concept of maximum flow is used defined the maximum burdening ability, and the concept of attack feasibility is put forward from the angle of two-dimensional analysis of network attack. The attack graph-based expanded Petri net attack net is represented, the ergodicity of the model’s related algorithms is assured by the EPN inference rules. When there are many arcs in an original attack graph, the complexity of the algorithm is lower than that of the Dijkstra algorithm. More is the paths among attack launching points and attack goals in an attack graph, more is efficient the algorithms. Results of a testing case show that the model can make a comprehensive analysis to network attack.
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Computer Engineering. 2011, 37(10): 134-136. https://doi.org/10.3969/j.issn.1000-3428.2011.10.045Aiming at the defects such as detection efficiency is still low, the application scope is narrow in currently detection methods, based on analyzing the impact of the correlation of traffic size and IP address caused by Distributed Denial of Service(DDoS) attacks, this paper proposes a method of detecting DDoS attacks based on the correlation of network flow, analyses the correlation of traffic size, defines the rate of variance of hurst exponent as the measure to distinguish the normal traffic and abnormal traffic which cause the original traffic increase notable. The correlation of IP address is analysed, flash traffic and DDoS attacks through the measure of degree of similarity are distinguished. Result shows that through combine correlation analysis of traffic size and IP address, it can distinguish DDoS attacks traffic from normal traffic and burst traffic, and raise the detection efficiency.
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Computer Engineering. 2011, 37(10): 137-139. https://doi.org/10.3969/j.issn.1000-3428.2011.10.046
Aiming at the privacy protection problem and message reliability problem in Vehicular Ad Hoc NETwork(VANET), a scheme for reliable message authentication and signature based on bilinear pair and pseudonym is proposed. The scheme uses self-generated pseudonym to sign each message, which can protect the user’s privacy and be verified efficiently at the same time. A priori counter measure for improving message reliability is given. The security and efficient analysis is also proposed.
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Computer Engineering. 2011, 37(10): 140-142. https://doi.org/10.3969/j.issn.1000-3428.2011.10.047As to the previous algorithms, the accuracy of matching is low and when the line segments are occupied, the matching is failure or even not to be implemented. Focusing on these instances, this paper presents a modified method. In matching, a new search method establishes a new contour of the model image via removing its lines corresponding to the missing lines, so it solves the problem that the procedure of matching can not be implemented when several line segments in model image are absence; and in matching, the Random Sample Consensus(RANSAC) algorithm is introduced to settle the problem of mismatch by removing the pairs of mismatching lines. Experiments demonstrate that the proposed algorithm can settle the problem brought by occupied lines, and promote the accuracy of the matching.
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Computer Engineering. 2011, 37(10): 143-145. https://doi.org/10.3969/j.issn.1000-3428.2011.10.048Dynamic Bayesian Network(DBN) learning with evolutionary MCMC algorithm is presented. Parameter learning with absent data is done with EM algorithm. In structure learning, multiple Bayesian network chromosomes are generated as candidates and are processed with mutation and crossover. The structures are learned with MCMC function which is obtained with temperatures and Bayesian Information Criterion(BIC) scores of corresponding Bayesian networks. In each generation, the Bayesian network with the maximal BIC score is selected as the result of the structure learning. Experimental results proves the stability of the method’s performance.
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Computer Engineering. 2011, 37(10): 146-148. https://doi.org/10.3969/j.issn.1000-3428.2011.10.049
To improve 3D facial expression feature regions segmentation, an automatic feature regions segmentation method is presented. The facial feature points are detected by conducting projection and curvature calculation, and are used as the basis of facial expression feature regions automatic segmentation. To obtain more abundant facial expression information, the Facial Action Coding System(FACS) coding rules is introduced to extend the extracted characteristic matrix. And facial expressions can be recognized by combining classifiers. Experimental results of 3D facial expression samples show that the method is effective with high recognition rate.
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Computer Engineering. 2011, 37(10): 149-151.Connected Dominating Set(CDS) has a wide range of applications in wireless networks. For the Minimal Connected Dominating Set(MCDS) problem, an approximation algorithm is presented based on an improved Distributed Learning Automata(DLA). The proposed algorithm considers not only the deeper exploration with random selections, but also the strategy of backtracking. The dominating tree is constructed using only neighborhood information, and some properties of the dominating tree are analyzed on Unit Disk Graph(UDG) to model networks. Experimental results on those graphs show the superiority of the proposed algorithm over the existing algorithms in terms of the MCDS size.
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Computer Engineering. 2011, 37(10): 152-153. https://doi.org/10.3969/j.issn.1000-3428.2011.10.051According to the prematurity matter of the Genetic Algorithm(GA), this paper gives a complex optimization method based on k-means and Quantum Genetic Algorithm(QGA). It accounts the center of the RBF neural network through k-means, and trains the weights of RBF neural network by QGA. The express and renewal of quantum chromosome is used to improve the parallel of this procedure, so the problem of prematurity is solved, the fitness of network is improved, and convergence speed of the network is improved compared with the PSO-RBF and ACO-RBF. Optimization of the RBF neural network is implemented.
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Computer Engineering. 2011, 37(10): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2011.10.052According to the needs of speech processing applications such as how to improve the naturalness of speech synthesis system, this paper presents for the first time the systematic empirical acoustical features analysis results of the tenuis consonants in Uyghur language based on the “Uyghur Acoustical feature Database”, which contains acoustical measurements of tenuis consonants contained in words such as p, t, k, q, which are recorded by 1 male and 1 female speakers separately, and finds the basics for the studying the prosody in words and sentences of Uyghur language. The aims and research results of this paper is to get a high value for further studying the Uyghur natural language processing techniques.
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Computer Engineering. 2011, 37(10): 157-159. https://doi.org/10.3969/j.issn.1000-3428.2011.10.053Support Vector Machine(SVM) is used to diagnose airplane hard landing. According to airplane’s motion equation of landing phase, major influencing factors are determined and extended airplane hard landing diagnosis from one index to several. Multi-kernel Support Vector Machine(MKSVM) is proposed, on this basis, airplane hard landing diagnosis model is established. Compared with traditional SVM and BP neural networks, the MKSVM diagnosis model is feasible and accurate, has high generalization ability.
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Computer Engineering. 2011, 37(10): 160-161. https://doi.org/njuwangwei@hotmail.com
On different distribution of multi-class imbalanced data, different base classifiers have different adaptability. To aim at the classifier selection problem, based on the analysis and comparison of the evaluation criteria of Accuracy(ACC) and Area Under the ROC(AUC), it chooses AUC to evaluate a classifier and draws the conclusion that Bayesian classifier is the best one and SVM classifier has greater room for improvement, through the experiments on dealing with many different distribution unbalanced data from standard database.
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Computer Engineering. 2011, 37(10): 162-164. https://doi.org/10.3969/j.issn.1000-3428.2011.10.055Classical Bayesian classifier which satisfies the assumption of condition attributes independent of each other can not use between-class information effectively. In order to solve this problem, an improved algorithm of Bayesian classifier combined with Fisher Linear Discriminant Analysis(FLDA) is proposed. This algorithm is the key to search the projection space of maximum separation. The original samples are projected to maximum separation space and new samples are obtained. These new samples are classifed by Bayesian classifier. Experimental results show that improved Bayesian classifier has higher accuracy of classification and better performance of classification in the given data collection.
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Computer Engineering. 2011, 37(10): 165-166. https://doi.org/10.3969/j.issn.1000-3428.2011.10.056In order to solve the feature extraction problem of nonlinear small sample sizes present in the traditional Fisher discriminant analysis method, a matrix transform is proposed on the basis of kernel linear subspace theory, by which a new kernel symmetrical linear subspace of within-class scatter matrix is constructed. Two kernel solution spaces derived from the within-class scatter matrix and its corresponding symmetrical subspace are respectively utilized to obtain the efficient discriminatory information of the samples. Experimental results conduct on the NUST603 and ORL face databases demonstrate the effectiveness of the proposed method.
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Computer Engineering. 2011, 37(10): 167-169. https://doi.org/10.3969/j.issn.1000-3428.2011.10.057This paper proposes a new feature selection method based on relative entropy for feature selection, which is one of the key technologies in text categorization. Based on that text category is decided by limited keywords, this paper uses relative entropy to select the words distinguishing effectively between one category and another. Experimental results show that the proposed method can effectively reduce feature dimension and improve precision rate.
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Computer Engineering. 2011, 37(10): 170-172. https://doi.org/10.3969/j.issn.1000-3428.2011.10.058Focusing on the problem of the process of refreshing, the knowledge point is so weak that it is bad for getting the optimization resolution in social cognitive algorithm. Through bringing in the chaos and Kent mapping function to modify and optimize the conditions of neighborhood search, it can get more reasonable knowledge points which are distributed more uniformly. Using the compared data, it can find that the speed of convergence and the legitimacy is better than before, and the value of the object function is closed to the theory value.
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Computer Engineering. 2011, 37(10): 173-175. https://doi.org/10.3969/j.issn.1000-3428.2011.10.059In order to make glue-robot fit for variable shoe sole, a small robot with camera is proposed in this paper. Mechanism is designed and kinematics model is derived. Then based on Matlab/Simulink, simulation platform is established and motion is simulated. Two-layer hierarchical control system is designed. USB camera is used to capture sole image and edge is detected using VC++ procedure. Edge track is translated to joint angle curve through kinematics model. Brushless DC motor is adopted to driven joint and controlled by DSP using incremental PID control algorithm. Tests are done on the self-develop robot prototype. Results show that intelligent glue-robot proposed can work for various sole and system is applied.
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Computer Engineering. 2011, 37(10): 176-178. https://doi.org/10.3969/j.issn.1000-3428.2011.10.060
In the process of building manual system relying on multi-Agent, the factors such as the difference of Agent’s interests, the limited resources and so on will inevitably lead to conflict. While effective consultation and competition between multi-Agent helps to reduce conflict and improve overall performance. It proposes a new multi-Agent negotiation competition model, which relies on negotiation information to improve the forecast accuracy of opponent’s competing strategies, depends on probability to selection strategies to maximize the interest and shortens negotiation time effectively.
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Computer Engineering. 2011, 37(10): 179-181. https://doi.org/10.3969/j.issn.1000-3428.2011.10.061Problem of big computation volume and low classifying velocity exists in conventional Support Vector Machine(SVM) multi-value classifying algorithm in constructing several two-value classifiers. For this, a SVM multi-value classifying algorithm based on covering is put forward. The covering thought is introduced into SVM algorithm and the tighter optimizing area can be found by constructing covering, which makes the classifying velocity improve notably. The algorithm is applied in radar emitter recognition. Simulation results show it is of excellent performance.
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Computer Engineering. 2011, 37(10): 182-183. https://doi.org/10.3969/j.issn.1000-3428.2011.10.062Aimed to extract the horizon from volatile sky/ground scene of the landing field, a horizon sequential extraction algorithm for Unmanned Aerial Vehicle(UAV) landing, which combines Ostu methods with Hough Transform is proposed in this paper. In the algorithm, basing on the original horizon determination, a subimage area, which includes the target horizon, is acquired by means of overstriking the original horizon. Experimental results show that the algorithm can accurately and effectively extract the horizon from different sky/ground scene.
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Computer Engineering. 2011, 37(10): 184-186. https://doi.org/10.3969/j.issn.1000-3428.2011.10.063Automatic extracting protein-protein interaction information from biomedical literature can help to build protein relation network and design new drugs. This paper presents a multiple kernels learning based approach to automatically extract protein-protein interactions from biomedical literature. The approach combines feature-based kernel, tree kernel and graph kernel. In particular, it extends shortest path-enclosed tree and dependency path tree to capture richer contextual information. Experimental evaluations show that the method can achieve state-of-the-art performance with respect to comparable evaluations, with 63.9% F-score and 87.83% AUC on the AImed corpus.
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Computer Engineering. 2011, 37(10): 187-188. https://doi.org/10.3969/j.issn.1000-3428.2011.10.064
The traditional clustering method is prone to fall into local extremum. It is bad to classify when the data is linear inseparable. This paper proposes a fuzzy kernel clustering image segmentation method based on maximum entropy. It applies maximum entropy algorithm to obtain the initial centers and maps the sample from the input space to the feature space by introducing Mercer kernel function into the method. It completes image segmentation in the feature space. Experimental result shows that the method can reduce the iteration time and steady the class result, and effectively segment the target from its background.
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Computer Engineering. 2011, 37(10): 189-191. https://doi.org/10.3969/j.issn.1000-3428.2011.10.065By combining the multiscale, multidirection, anisotropy and shift-invariant of Nonsubsampled Contourlet Transform(NSCT) transform and effective approach characteristic of Taylor series, this paper propose a superresolution image reconstruction algorithm, which uses Taylor series to replace double-line. Experimental result shows that the algorithm can recovery the detailed information and texture features of image, and resist Gaussian noise.
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Computer Engineering. 2011, 37(10): 192-194. https://doi.org/10.3969/j.issn.1000-3428.2011.10.066Aiming at the limitations of the traditional Chan-Vese(CV) model applied to the highway pavement disease image segmentation. An improved CV model based on the gradient information is proposed in this paper, which can successfully segment the region with different texture caused by road damage. The threshold of the gradient is introduced to the model which combines the intensity information and the texture information, and increases the flexibility of the method. Experimental results show that the segmentation effect of the improved CV model is better than the traditional CV model.
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Computer Engineering. 2011, 37(10): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2011.10.067Aiming at the limitation of correlation method of subjective assessment and its poor effect when facing the problems of local optimum, nonlinearity, higher dimension and small sample, the objective assessment indexes of image quality such as Mean Square Error(MSE), Peak Signal to Noise Ratio(PSNR) and Singular Value Decomposition(SVD), and the scores from LIVE database are used as the learning sample. By using Support Vector Machine(SVM) to train a correlation function between subjective and objective and Genetic Algorithm(GA) for parameter optimization, a perfect model is obtained to achieve the consistency of subjective and objective. Experimental results show that compared with traditional methods, the assessment with the method is more accurate.
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Computer Engineering. 2011, 37(10): 198-199. https://doi.org/10.3969/j.issn.1000-3428.2011.10.068
The processing of smooth region and edge region is identity using Markov Random Fields(MRF), which leads to a lot of redundancy program and too long operation time. Aiming at this problem, this paper presents MRF image restoration method based on fuzzy classification. Image subblock can be fuzzy classified according to its statistical characteristics obeying different distribution, the image can be restored by MRF. The blurred binary image is restored by this method and the experimental results show that comparing with the MRF method, the method based on fuzzy classification can reduce operation time and improve denoising effect.
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Computer Engineering. 2011, 37(10): 200-201. https://doi.org/10.3969/j.issn.1000-3428.2011.10.069
Aiming at the problems of characteristic extraction and description in image recognition, retrieval and registration, by using eigenvalue decomposition approach for weighted graph, this paper constructs boundary shape descriptor and spatial relation descriptor based on metric matrix eigenvalue, which is invariant under translation, scaling and rotation. Analysis and experiments prove that the spatial relation descriptor is robust under translation, scaling, rotation and small noise, and it has good similarity discriminating ability. Compared with traditional algorithms, it can describe image better with less computation.
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Computer Engineering. 2011, 37(10): 202-203. https://doi.org/10.3969/j.issn.1000-3428.2011.10.070
An adaptive Fuzzy C-Means(FCM) method for image segmentation based on fuzziness rate is proposed. It automatically determines the proper number of fuzzy clustering by utilizing the gradient detection method of wave trough and peak. Accurate original cluster centers are acquired by utilizing fuzzy threshold method. A novel objective function is established which contains feature information and spatial information. Experimental results show that the method has fast segmentation speed and high segmentation accuracy, and has stronger robustness.
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Computer Engineering. 2011, 37(10): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2011.10.071This paper combines the characteristics of Moving Picture Experts Group Audio Layer 3(MP3) encoding, and presents a digital watermarking algorithm for MP3 audio files. It goes on watermark embedding and extraction directly in the compressed domain. The watermark is embedded in MP3 by slightly modifying the scale factors in bit stream, the method does not need encode the sound data into an MP3 file or decode the MP3 file. Experimental results show that the size of the audio file is not changed in the embedding process, and it does not need original audio file when watermark is extracted. The algorithm has advantages of higher real-time, lower computational complexity and excellent imperceptibility.
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Computer Engineering. 2011, 37(10): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2011.10.072TV commercial detection using audio features has many advantages such as high speed and accuracy. This paper presents a fast and robust audio fingerprint extraction algorithm. The optimized frequency domain is divided into 33 bands, and the energy differences of the neighbor bands in current frame and in the previous frame are extracted separately. And the sum of the energy differences is set as corresponding value of 0 or 1. The audio fingerprint can be generated by 32 values of 0 or 1 in each frame. Experimental results show that the method proposed ensures high extraction speed and robustness against common audio signal operations.
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Computer Engineering. 2011, 37(10): 210-212. https://doi.org/10.3969/j.issn.1000-3428.2011.10.073In order to improve robustness and reliability of the composite service path in distributed multimedia service composition system, this paper presents an anomaly prediction algorithm based on Markov chain and Weighted Na?ve Bayesian Classification(WNBC). It adopts Markov chain model to predict the resource states of the node. Based on the prediction, a WNBC is introduced to determine whether an exception occurs in the node. Simulation results demonstrate that the proposed algorithm can predict the anomalies effectively according to the states of node, and its performance is improved compared with previous algorithms.
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Computer Engineering. 2011, 37(10): 213-215. https://doi.org/10.3969/j.issn.1000-3428.2011.10.074Aiming at data transmission question of Internet Protocol Television(IPTV) in 802.11 Wireless Local Area Network(WLAN), this paper proposes a video streaming multicast optimization mechanism, in which the key I-frames are transmitted by using reliable multicast communication mechanism and B-frames and P-frames are transmitted by using multicast communication mechanism. Simulation results show that the mechanism based on frame classification can get a flexible compromise between frame loss rate and packet delay, especially when wireless network bandwidth is insufficient, it improves the watching quality of video after data transmission.
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Computer Engineering. 2011, 37(10): 216-218. https://doi.org/10.3969/j.issn.1000-3428.2011.10.075In order to solve the problems that current false color image fusion method results in single hue and color transfer algorithm leads to huge computing amount, a novel false color fusion method is proposed and used to fuse infrared and visible digital videos. It imposes statistical properties to mapping color lookup table and transfer color rapidly, and makes the fusion result have the same color information with the reference image based on Toet algorithm. Experimental result shows that the algorithm is fast and convenient for real-time digital video processing, and the color-transferred image has better natural color perception than the conventional false color image.
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Computer Engineering. 2011, 37(10): 219-220. https://doi.org/10.3969/j.issn.1000-3428.2011.10.076Conventional adder adding the required number of signed operands into the form of complement operations，and return a result in signed magnitude number. This paper proposes a new structure one’s complement Signed Adder(SA) based on the flagged prefix adder, which could combine the increment unit with the adder, to reduce the delay of the signed adder. A 64-bits enhanced SA has been implemented in SMIC 180nm CMOS technology. Compared with previous work, the area, power, and delay of our design are decreased by 39.1%, 39.9%, and 5.1%, respectively. Results show that this structure is superior to two’s complement adder.
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Computer Engineering. 2011, 37(10): 222-225. https://doi.org/10.3969/j.issn.1000-3428.2011.10.077A serial data recover algorithm based on over-sampling is advanced to implement serial communication inside a sensor network measurement system. After analysis of composition of clock data recovery, phase detection and data discrimination are researched, and influences of frequency difference on them and corresponding solution are demonstrated in detail, then theoretical proof on performance parameters of this serial transfer technology is given. Modeling and algorithm tests using SystemC class through serial interface engine are prompted. Theoretical analysis and tests showed that serial data stream can be recovered within clock disparity of 3%.
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Computer Engineering. 2011, 37(10): 226-227. https://doi.org/10.3969/j.issn.1000-3428.2011.10.078In atmospheric interference modulation system of vertical detection, this paper presents a current acquisition system design which is applied in space remote sensing instruments according to the stability of the scan mechanism of mirrors driven by oscillating motor in sounder. The peripheral circuit can work together harmoniously under the control of Field Programmable Gate Array(FPGA), and the output of current signals of oscillating motor can be sampled and transferred. Experimental result shows that the current waveform get by this system is consistent with theoretical analysis, and it has high stability.
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Computer Engineering. 2011, 37(10): 228-230. https://doi.org/10.3969/j.issn.1000-3428.2011.10.079According to the analysis of addressing mode of ARM instructions, the number of registers, and the number of instructions cycles etc, this paper considers the influence of three-level pipelining to the energy and proposes a hierarchical classification energy consumption measurement method. Experimental result shows that this method can efficiently measure the power consumption of the instruction set, and concludes that the energy consumption of instruction set is nonnegative with the product of current and the instruction cycles. Reducing the cycles can reduce the energy of instruction set. The measured energy value of 3 kinds of program executed on HMSim simulator is close to the energy of executed on the target board W90P710, the absolute error is below 10%.
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Computer Engineering. 2011, 37(10): 231-233. https://doi.org/10.3969/j.issn.1000-3428.2011.10.080According to the analysis of the current situation of the information integration for die & mould enterprises, this paper presents a service-oriented, loose-coupled, reusable Enterprise Service Bus(ESB) which is based on the content-based router. It realizes the information integration among die & mould enterprises, unifies the ESB-collocation. Interface and fulfill the application integration among systems and departments, which reduces the difficulty and costs of the implementation of the application integration for enterprises.
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Computer Engineering. 2011, 37(10): 234-236. https://doi.org/10.3969/j.issn.1000-3428.2011.10.081After a thorough study on M/N Logic-based method and one-step delaying method for track initiation, this paper proposes a novel track initiation method based on the combination of the above two methods. It adds a limitation to the measurement from related district, which relatively simplifies the track initiation. It reduces the influence clutter made on track initiation by comparing weight and threshold from two adjacent periods. This approach can initiate the track properly and shorten the time of initiation at the same time under the guarantee of low false track probability. It is appropriate to the multi-target track initiation under dense clutters. Simulation results testify the validity of the present method.
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Computer Engineering. 2011, 37(10): 237-239. https://doi.org/10.3969/j.issn.1000-3428.2011.10.082
In embedded systems, this paper proposes a Dynamic Power Management(DPM) scheme based on Linux Dynamic Frequency Scaling(DFS). The scheme can achieve more than 2 levels of the frequency of adjustments, and provide users with the interface which is used to setting system frequency level, thus add the function to help the user select automatically, so that it solves the numerical restrictions problem, that is relying solely on the system to automatically adjust the frequency level. And it separates the application layer, the kernel layer, and the driver layer from each other, thus enhances the portability of code. The realization result of S3C2440A platform proves the validation of this scheme.
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Computer Engineering. 2011, 37(10): 240-242. https://doi.org/10.3969/j.issn.1000-3428.2011.10.083
A new reciprocal algorithm is provided to realize the traditional reciprocal division on Field Programmable Gate Array(FPGA) with high precision and fast speed. In order to solve the reciprocal of the divisor, the Taylor series expansion is used combining with searching approximation to get a fitting binomial of degree 1 with one variable in every separated section, and the Newton-Raphson iteration is used one time to improve precision. The result of timing simulation proved that the divider based on this new division algorithm can be easily realized on FPGA. The divider can get the answer of 2-34 available accuracy only six clock pulses after input variables being given, and the highest operating frequency is 86.95 MHz.
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Computer Engineering. 2011, 37(10): 243-245. https://doi.org/10.3969/j.issn.1000-3428.2011.10.084
This paper proposes a design and implementation of intelligent model car based on Renesas H8/3048-one Single Chip Microcomputer(SCM). The model car uses infrared sensors to obtain lane image information, and employs the H8/3048-one as its control micro-processor. Through the open-loop proportional control on servo to change the direction and the closed-loop Pelvic Inflammatory Disease(PID) control on motors to implement the control the speed, it can realize to track the lane automatically. Practice proves that the scheme is reasonable and effective to make the model car pass the crank, lane change and other special lane smoothly, it has the characteristics of optimal tracing line, fast adjustable speed, strong anti-interference performance, little steady-state error, and it also has good dynamic and steering performance.
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Computer Engineering. 2011, 37(10): 246-248. https://doi.org/10.3969/j.issn.1000-3428.2011.10.085As disk capacity increases, the probability of partial disk failure increases. This paper presents a Multilevel Array’s Recovery System (MARS)to save recovering time when recover a degraded array and reduce the rebuild frequency. The MARS system will choose bad-sector- remapping(MARS-1), or data-migrating-between-disks subsystems(MARS2), or Redundant Array of Independent Disk(RAID) rebuild to recover RAIDs according to different disk health status. Experiment results shows that the MARS system can save recovering time and reduce the rebuilding frequency obviously. Besides, the I/O performance of the RAID may not drop during the recovering.
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Computer Engineering. 2011, 37(10): 249-251. https://doi.org/10.3969/j.issn.1000-3428.2011.10.086According to the theory that the scattered point cloud data of buildings is certainly located on their contour line, this paper proposes a data reduction algorithm of clustering plane feature so that the scattered point cloud data of large group of ancient buildings can achieve a higher reduction ratio on the basis of maintaining the shape feature. Appling it to reconstruct the Small Wild Goose Pagoda with point cloud techniques achieves good modeling results.
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Computer Engineering. 2011, 37(10): 252-254. https://doi.org/10.3969/j.issn.1000-3428.2011.10.087To solves some common problems in 2D data processing such as data alignment and address mapping, this paper presents the mechanism of 2D block data access in multi-core system. It introduces the principle of data mapping, addressing, and data transmission. It applies a general method. Simulation result proves that the mechanism can increase the efficiency of data access and decrease the imbalance between 1D and 2D.
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Computer Engineering. 2011, 37(10): 255-256. https://doi.org/10.3969/j.issn.1000-3428.2011.10.088
The envelope area of the body barycenter swaying trajectory is one of sensitive indicators that discriminates the balanced capacity of dizziness patient. Traditional computing method firstly determines the shape of convex hull enveloping all points and then calculates the area of convex hull, it need sort all points, time complexity of algorithm close to O(nlbn) on the best cases. This paper introduces a kind of algorithm of approximate convex hull, calculates coordinates of different rotation angle, looks up the point set of maximum and minimum along X-axis and Y-axis, quickly marks the points and make sure the shape of convex hull. Time complexity of algorithm close to O(n). It is proved that the algorithm can meet accuracy requirement of balance test system, and increase calculation speed.
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Computer Engineering. 2011, 37(10): 257-259. https://doi.org/10.3969/j.issn.1000-3428.2011.10.089This paper analyzes the anti-collision algorithm in existence, and proposes a new algorithm based on binary-tree search algorithm with matrix form. The algorithm takes use of several bits but not one as search prefix. It means that the search prefix is made up of non-collision bits and collision bits. When continuous collision is appeared, it takes quad tree structure and when there is only one collision bit, it takes binary-tree structure. In this way, the time of identifying the tag is shorter and it also proves to be effective.
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Computer Engineering. 2011, 37(10): 260-262. https://doi.org/10.3969/j.issn.1000-3428.2011.10.090In order to eliminate aliasing noise signal of gastric motility impedance signals, using independent component analysis of the redundancy reduction features, a new method of gastric motility impedance signals denoise is proposed. Construction of virtual noise channel used empirical mode decomposition, the one-dimensional original gastric motility impedance signal is extended to multi-dimensional observation signals, and it is implemented blind separate by FastlCA algorithm. Simulation experimental results show that the denoise method can effectively eliminate the noise of gastric motility impedance signal. The method does not require a large number of observation samples, which can achieve denoise of a single observed sample by Independent Component Analysis(ICA).
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Computer Engineering. 2011, 37(10): 263-265. https://doi.org/10.3969/j.issn.1000-3428.2011.10.091
According to the feature of computer forensic, a method is proposed to reassemble JPEG fragment files and the reassemble progress is described. By analyzing JPEG file structure, an algorithm called JFDDM(JPEG Fragment Degree of Difference Matching) for reassembling JPEG fragmented files is proposed and discussed, by which the MCU’ degree of difference in the image and the similarity between adjacent pixels are exploited to decide whether current fragments fall within the same image. Experimental results show that this is an effective method for JPEG fragment reassembling.
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Computer Engineering. 2011, 37(10): 266-268. https://doi.org/10.3969/j.issn.1000-3428.2011.10.092This paper presents a self-adaptive framework of Architecture of Virtual Computing System(AVCS) which provides an idea to solve the problem of applications not matching the architecture of AVCS. Two self-adaptive reconfiguration algorithms oriented the change of dynamic requirements from applications and physical resources are designed in this framework, which enable the threads gathering and virtual machines gathering automated and form a new task assignment and scheduling structure to improve the performance of virtual computing systems. Meanwhile, the virtual machines migration in the algorithms is implemented to keep the load balancing.
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Computer Engineering. 2011, 37(10): 269-271. https://doi.org/10.3969/j.issn.1000-3428.2011.10.093
The bus topology of 1553B is analyzed. A new topology of composite bus topology based on parallel bus topology and hierarchical bus topology is designed, and the communication protocol stack is put forward. The transport layer based on transmit vector word is given. The process of message transfer and the structure of vector word and message are also introduced, as well as the data clustering of network layer. It realizes the testing software based on LabVIEW.
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Computer Engineering. 2011, 37(10): 272-274. https://doi.org/10.3969/j.issn.1000-3428.2011.10.094The propagation of rumors is similar to virus spreading in social networks. This paper builds SIR model and discusses the propagation taking into account topology of microblogging communication network and the rules of rumor. The mathematical derivation and computer simulation reveal that the propagation is impacted by the infection rate and degree distribution entropy. More serious the infection rate affects, more enormous the scale of infection is. Smaller the degree distribution entropy is, easier the rumors spread in it.
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Computer Engineering. 2011, 37(10): 275-277. https://doi.org/xxgcxyzf2008@163.comBack Projection(BP) is the most time-consuming and sophisticated part of the most Cone Beam Computed Tomography(CBCT) reconstruction algorithms. It realizes BP parallel computing by using body element driving method under the model of CBCT, and optimizes memory access and mathematics instruction. The actual CT data reconstruction results indicate that the operation speed of this method is 198 times that CPU serial program, and it has high efficiency and easy implementation.
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Computer Engineering. 2011, 37(10): 278-280. https://doi.org/10.3969/j.issn.1000-3428.2011.10.096
This paper puts forward a real 3D visualizing entity modeling method based on Multi-Scale Spatial Voxel Volume(M-S SVV), discusses the method of modeling and visualization of geological entity and field, develops the software. The structure and physicality data of Dongying depression and Huagou area is used for 3D modeling and visualization. The application results show this method has good adaptability for the geologic data, and is able to meet the demands of the M-S expression and analysis in geologic space. It supplies an effective way for the displaying and analyzing of the geologic data, provides the basic services for the professional analysis and modeling of geology, geophysics and other disciplines.
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Computer Engineering. 2011, 37(10): 281-283. https://doi.org/10.3969/j.issn.1000-3428.2011.10.097In flight data processing, manual analysis is of great labor intensity, low work efficiency and high probability of mistake and omission, which restricts the application of flight data as assistant of ground service. This paper researches establishing flight data criterion to analyze flight data automatically, which can improve the efficiency, decrease the omission rate, and promote application of flight data in ground service. The flight data criterion is defined, the methods and principles in its establishing are expounded, and the construct which is suit for use is made up. And an example of its application shows that flight data criterion can help to get interpretation results quickly and accurately.
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Computer Engineering. 2011, 37(10): 284-286. https://doi.org/10.3969/j.issn.1000-3428.2011.10.098
This paper proposes the thought of getting the edges of exact solution to access the approximate solution of the whole Traveling Salesman Problem(TSP). On the basic of the thought, a new algorithm called collision algorithm is designed. Experiments with the test data from internationally accepted TSPLIB in different cities and size show that the results got through the algorithm is the same or similar with current optimal solution. The algorithm can apply the TSP on a large scale as well as small scale ones.
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Computer Engineering. 2011, 37(10): 287-290. https://doi.org/10.3969/j.issn.1000-3428.2011.10.099Aiming at the characteristics of combat system under the condition of information flight, this paper puts forward an extended FINC(Force, Intelligence, Network, and C2) model. On the basis of this model, it proposes the efficiency measures of the combat system with a quantitative method from the aspects of intelligence delay, unit coordination, execution ability and decision support, reflecting the corresponding combat capability. Experimental result demonstrates the significance of this method in the evaluation of information flow and coordination capacity.
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Computer Engineering. 2011, 37(10): 291-293. https://doi.org/10.3969/j.issn.1000-3428.2011.10.100In order to assure the information security of financial ATM, this paper studies and analyzes the keyboard and mouse drivers in Windows operating system, and based on filter driver, designs and implements keyboard and mouse insertion authorization system. The authorization system can detect the insertion of USB or PS/2 interfaced keyboard and mouse into the computer, and keeps the new device disabled before authorized. The final tests demonstrate that the system can be deployed and run on Windows XP and Windows 7 stably and efficiently.
Volume 50 No 4
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428