15 May 2013, Volume 39 Issue 5
-
Select all|
-
Computer Engineering. 2013, 39(5): 1-4. https://doi.org/10.3969/j.issn.1000-3428.2013.05.001
Regarding the intelligent network management system, the traditional systematic sampling method is unable to monitor to the modern information network in real-time. In order to solve this problem, this paper presents a fuzzy self-adaptive sampling method. Based on the fuzzy control principle, the method can dynamically adjust the sampling interval using the set of membership functions and fuzzy rules, and it can detect the network anomaly and network bottlenecks in the minimize of affecting network latency and network bandwidth. Experimental results show that this method is less than the system sampling method 69% based on the same error condition, and the errors of fuzzy adaptive sampling method are less than the system sampling method 54% in the equal sample count.
-
Computer Engineering. 2013, 39(5): 5-11. https://doi.org/10.3969/j.issn.1000-3428.2013.05.002
Dozens or even hundreds of virtual routers may be deployed in a memory limited physical router. To save memory overhead, this paper proposes an algorithm named optimal trie merging algorithm. It adopts dynamic programming approach to find the nodes for initial merging of each trie, and computes the number of nodes of the optimal trie. The sub-node arrangements of any two nodes, which achieve optimal matching, are written down in the process of dynamic programming computation. Then, according to the three computation results, it constructs a data structure named optimal trie. Experimental results show that the algorithm saves 20%~90% memory overhead than simple trie merging algorithm.
-
Computer Engineering. 2013, 39(5): 12-17. https://doi.org/10.3969/j.issn.1000-3428.2013.05.003
This paper designs a path planning system for crane lifts. The problem of lift path planning is formulated. The architecture of this system is proposed. The overview of path planning approaches is focused on for crane lifts. The paper introduces the implementation of path planning module. Experimental results show that this system is able to visualize the result of one certain path planning algorithm and compare the performance of several algorithms under the same condition. Besides, this system allows users not only easily to append new algorithm, but also handily to add new lift path planning problem.
-
Computer Engineering. 2013, 39(5): 18-22,27. https://doi.org/10.3969/j.issn.1000-3428.2013.05.004
A novel Artificial Fish Swarm Algorithm(AFSA) based on differential evolution is proposed, which aims to accelerate convergence and improve accuracy of AFSA, and refers to the strategy of globel fish swarm cluster and trace action. The fish cluster for the whole fish center and trace with the bulletin board record in the algorithm. Meanwhile, it is set stagnation threshold and stagnation record in the bulletin board so that fish can execute the differential evolution for out of local minima in the stagnation stages and overcome the lack of purpose of the fish search by it. The convergence and accuracy of the algorithm are improved significantly after evolution. Comparing to the results of other AFSAs and Particle Swarm Optimization(PSO), result shows that the algorithm has better optimization effects.
-
Computer Engineering. 2013, 39(5): 23-27. https://doi.org/10.3969/j.issn.1000-3428.2013.05.005
The method of distance measurement system based on single Duffing system has large system error and determining system state is complex. Aiming at these problems, this paper proposes a novel method of ultrasonic distance measurement based on Duffing oscillator coupled synchronization system. It adopts the coupled synchronization system to receive the echo signal, and according to the output signal of the synchronization system hop or not to determine whether the echo signal arrives, so that the method can achieve accurate ranging. By using the system’s property of being immune to noise, it can not only reduce the effect of noise, but also improve the measuring distance, and determining system state is simple. Simulations are given to verify the feasibility of the proposed method.
-
Computer Engineering. 2013, 39(5): 28-33. https://doi.org/10.3969/j.issn.1000-3428.2013.05.006
A recent path loss measurement is presented in two typical kinds of outdoor urban application environment for Wire- less Sensor Network(WSN) channel model in three different frequency channels. The measured data are analyzed by least square linear regression method. The results indicate that radio channel is different from the traditional one, but two slope log distance path loss models are still acceptable. The analysis outcome can provide the evidence of design and engineering application for WSN in urban application environment.
-
Computer Engineering. 2013, 39(5): 34-41. https://doi.org/10.3969/j.issn.1000-3428.2013.05.007
In order to enhance efficiently a degraded video image in various scenes, a new adaptive image enhancement algorithm is proposed. The new algorithm uses Laplacian operator for extraction of image detail, constructs and uses different grey-level conversion strategy for images in different scenes based on dynamic scene estimation, and adaptively adjusts image’s gray-level range to improve the performance of image enhancement. By using line buffer and pipeline structure, the algorithm has a good timing performance and compact hardware implementation with minimum use of memory resource. Experimental result shows that the proposed algorithm has satisfying performance in each scene, while has a careful protection of image’s original details.
-
Computer Engineering. 2013, 39(5): 42-47. https://doi.org/10.3969/j.issn.1000-3428.2013.05.008Aiming at the problems in current study on cloud services purchase decision that ignoring fluctuations in users’ demands, as well as potential risks, this paper makes a study of multi-instance combination decision for minimizing customers’ cost under cloud demands fluctuation with taking risk cost into consideration, describes the conditions and the reasons for optimal decision with a case in detail, and analyzes the relationship between demand fluctuation, effective working time, risk sensitive factor and optimal decision. Analysis results show that, compared with the existing research, this method can minimum total cost with users’ resource needs guaranteed.
-
Computer Engineering. 2013, 39(5): 48-52. https://doi.org/10.3969/j.issn.1000-3428.2013.05.009Aiming at the problem of the data uncertainty in information gathering system, a multi-sensor information fusion method based on fuzzy set and evidence theory is proposed, in which the fuzzy support probability of the uncertain information is defined by the correlation function. Credibility of the information measured by each sensor is obtained by using the membership function. The support and credibility are transformed into basic probability assignment function. The sensors with higher measurement precision are identified by D-S evidence combination. Practical application results show that this method can improve the problems that basic probability assignment function is difficult to be determined and the calculation of degree of mutual support is absolute, and the fusion result has higher accuracy and reliability.
-
Computer Engineering. 2013, 39(5): 53-56,60. https://doi.org/10.3969/j.issn.1000-3428.2013.05.010Locally Linear Embedding(LLE) algorithm can achieve data dimensionality reduction by finding the local linear low-dimensional manifold hidden in the high-dimensional space. The LLE algorithm is sensitive to noise, moreover, the stability of the algorithm is very poor when exposed to strong noise. This paper proposes a sparse constraint improvement method, by adding L1 norm punitive constraint to the reconstruction error function, the optimal reconstruction weight matrix is sparser. Transform the reconstruction error function which adds the sparse constraint into a general quadratic programming problem by regularization, and uses interior-point iteration method to search the optimal solution quickly. Simulation experimental results of the typical high-dimensional data set dimensionality reduction show that the dimensionality reduction results of the LLE algorithm in sparse constraint is significantly better than the classic LLE algorithm under the influence of different noise, and has a stronger ability in resisting noise.
-
Computer Engineering. 2013, 39(5): 57-60. https://doi.org/10.3969/j.issn.1000-3428.2013.05.011This paper presents a polygonization method of simple linestrings based on topology in Geographic Information System(GIS). Simple linestrings are preprocessed using topological data structure rule to construct topological relationship between node and edge, then graph theory is used to implement Depth First Search(DFS) to detect the closed polygon in the linestrings set. Experimental results show that topology based method can identify complex intersect condition and handle degeneration polygon well.
-
Computer Engineering. 2013, 39(5): 61-64,68. https://doi.org/10.3969/j.issn.1000-3428.2013.05.012Multi-sensors are often used when testing in a complex environment, however the results sometimes are difficult to interpret especially when data distribution is irregular and even inconsistent. This paper presents a new analysis and fusion method which focuses on the distribution analysis for all the data rather than just making the weights for each single sensor in the traditional ways. It uses a fuzzy gradient function to quantify the consistent degree of the sensor data, and makes an algorithm for cluster analysis. The method integrates data by using the supportive degree. Experimental results show that the method can make a better integration and also can help to find faults.
-
Computer Engineering. 2013, 39(5): 65-68. https://doi.org/10.3969/j.issn.1000-3428.2013.05.013To remedy the deficiency of the existing methods about the 3D direction relations, based on the 3DR44 direction relations model, the 3D dynamic direction relations and the reverse relations are researched emphatically. The dynamic direction relations induced by the change of the shape and size of the reference object are dealt with, the dynamic migratory characteristics of the direction blocks are studied. The complex 3D reverse direction relations are predicted and analyzed, the relevant information of the positive relations and the reverse relations of the direction space elements in the 3DR44 direction relations model are given. Application results show that this research work can enhance the ability to represent the complex 3D direction relations of the spatial database.
-
Computer Engineering. 2013, 39(5): 69-72,77. https://doi.org/10.3969/j.issn.1000-3428.2013.05.014Dempster Shafer Theory(DST) fusion accuracy is higher than Dezert Smarandache Theory(DSmT) under low-conflict conditions, and DSmT fusion accuracy is better than DST under high-conflict conditions. In order to obtain more accurate fusion results, through combining advantages of DST and DSmT, this paper proposes an adaptive information fusion algorithm based on DST and PCR2. The allocation rules under DSmT framework are analyzed, and the rule of PCR2 is selected because of its higher accuracy and lower complexity. Adaptive fusion algorithm is given using PCR2 and DST, PCR2 is employed when there are higher conflicts, and DST is employed when there are lower conflicts. Numerical results show that this algorithm obtains better fusion results and its complexity is between DST and PCR2.
-
Computer Engineering. 2013, 39(5): 73-77. https://doi.org/10.3969/j.issn.1000-3428.2013.05.015Aiming at the problem of load latency and power consumption in deep pipeline, this paper proposes a method of getting data immediately which is based on base address register. Building locality accessing history between base address register and destination data dynamically during the execution of load instruction, and designing a base address register tracking buffer, which let load instruction get data immediately at decode stage. This method accelerates the speed of load instruction to get destination data, and avoids address calculating and cache accessing. Results of benchmark show that performance of processor with this method increases about 3.7% averagely, and data cache power reduces about 18.7% averagely.
-
Computer Engineering. 2013, 39(5): 78-83. https://doi.org/10.3969/j.issn.1000-3428.2013.05.016Current research review on interaction test of composite services is given, including model check of composite services, requirements monitoring of composite services, generation of test case, and test oracle. An important research issue is to find more interaction errors in implementation of composite services accurately. About this issue, three areas are focused, including formal flow of composite services for test analysis, obtaining of dynamic test information related to interaction and analysis of dynamic test information.
-
Computer Engineering. 2013, 39(5): 84-87. https://doi.org/10.3969/j.issn.1000-3428.2013.05.017There are two problems in normal schedulers, one is that threads with different contexts cost a lot while scheduling, another is that it is unfair to allocate time slice without considering thread-number of process. This paper proposes a Fast Context Switching Scheduler(FCSS) algorithm. It takes threads belonging to the same process as close as possible in the ready queue, and the total amount of threads into consideration when allocating time slice. Experimental results show that the algorithm reduces the cost of switching of the system, controls the total amount of time slice, and improves the efficiency and fairness of the system.
-
Computer Engineering. 2013, 39(5): 88-91,100. https://doi.org/10.3969/j.issn.1000-3428.2013.05.018The definition of cluster supply chain is proposed as a new management pattern to help small and medium-sized enterprises realize “ant colony effect” and gain more profit. But the research of cluster supply chain is still at an early stage and is short of technology support. Aiming at this problem, this paper presents a method that builds business logic models of cluster supply chain by adopting the technology of Agent, Agent models map to the corresponding Web Service models according to mapping rules and builds functional models by adopting the technology of Web Service, which combines modeling technology with economic management technology, the economics and sociology essence what is behind phenomenon is dug out through repeating experiments, so cluster supply chain can be explored deeply.
-
Computer Engineering. 2013, 39(5): 92-95,105. https://doi.org/10.3969/j.issn.1000-3428.2013.05.019This paper presents a dedicated architecture of texture mapping unit with an optimized design of single-precision floating-point divider and texture Cache, against the processing speed and memory bandwidth problem. It uses a small look-up table with quadratic polynomial approximation algorithm to achieve floating-point division. According to different sampling methods, it configures Cache mapping strategy among direct mapping, two-way set associative mapping and four-way set associative mapping. The design of the texture mapping unit is synthesized under SMIC0.13 μm CMOS process technology. Experimental results show that the design can achieve frame rate up to 51 f/s for 480×640 resolution at frequency up to 313 MHz, it is efficient for real time rendering for mobile devices.
-
Computer Engineering. 2013, 39(5): 96-100. https://doi.org/10.3969/j.issn.1000-3428.2013.05.020It becomes difficult to play the games that need face-to-face mechanism to ensure the fairness on Internet. Bit Commitment(BC) can solve this problem. This paper, using public-key cryptosystem based on high degree composite residuosity classes, proposes a new bit commitment scheme, and then, using this BC scheme as building block, designs two protocols to implement the traditional rock, paper and scissors game for multi-players. These protocols use the homomorphism of the public-key cryptosystems to perform the counting function, to hide the information of the fail player’s promise, and to reduce the network overhead meanwhile. In design of these protocols, algorithmic game theory is introduced to guarantee that all players will loyally follow the prescribed game protocols. Analysis result shows that the traditional rock, paper and scissors game designed by the idea mentioned above can be achieved fairly and effectively in network.
-
Computer Engineering. 2013, 39(5): 101-105. https://doi.org/10.3969/j.issn.1000-3428.2013.05.021Aiming at the problems of the present social mining algorithms, which are primarily static and the accuracy is not high enough and stability is not enough to balance of the social networks which are constructed through present algorithms. This paper proposes a dynamic miming algorithm called Dynamic Mobile Graph Community Mining(DMGCM) which is based on mobile phone data. The main idea of this algorithm is that the social networks are dynamically constructed according to the specified time in a certain period. It is need to judge whether there is a change point in each time slice, the pervious social networks can be merged into present social networks if there exists a change point, so the complete social networks are constructed. It is necessary to analyze the mobile phone data and construct directed and weighted graph. A real dataset is used in the experiment and comparing the traditional random walk and shortest path algorithms with DMGCM algorithm. Experimental results show that algorithm effectively improves the accuracy of social networks and ensures growth trend gradually achieve the balance.
-
Computer Engineering. 2013, 39(5): 106-109. https://doi.org/10.3969/j.issn.1000-3428.2013.05.022For the reliability issues of the wireless transmission which energy is limited, this paper puts forward the probability expression to calculation the reliability of linear sensor network. It establishes a system model, which includes transfer model, energy model, link model and service model. By taking into account the energy consumption of sensors, it derives the reliability expression of the source node. Considering the condition of link, the normal operation probability expression of link is derived. The reliability expression of the transmission is obtained by comprehensive consideration of the nodes and link situations. Simulation results show that the reliability expression can provide sufficient precision for evaluating the reliable performance of wireless transmission.
-
Computer Engineering. 2013, 39(5): 110-113. https://doi.org/10.3969/j.issn.1000-3428.2013.05.023In the Internet of Thing(IoT), wireless data transmission is an important way for the information acquisition layer to abtain the information. This paper presents a Data Reliable Gathering Cross-layer protocol(DRGC) for wireless sensor nodes in the Internet of Thing(IoT) for the event detecting and reporting. This protocol includes a clock synchronization algorithm that balanced precision and energy consumption, and a cross-layer data gathering algorithm that fuses MAC and routing strategy. Simulation results show that DRGC effectively prolongs the network lifetime and reduces the communication delay in comparison with LEACH and PEGASIS.
-
Computer Engineering. 2013, 39(5): 114-117. https://doi.org/10.3969/j.issn.1000-3428.2013.05.024Traditional Transmission Control Protocol(TCP) calling congestion control mechanism in error in wireless networks leads to performance reduction. This paper presents an improved TCP protocol(TCP-FR) to improve this problem. The protocol distinguishes network congestion packet loss and link error packet loss by the trend of data relative transmission time delay. It divides network congestion level according to the degree of network congestion and adjusts the size of congestion window dynamically. Simulation results show that the algorithm improves the accuracy of network congestion judgment, and effectively improves the channel utilization and throughput of the network.
-
Computer Engineering. 2013, 39(5): 118-122. https://doi.org/10.3969/j.issn.1000-3428.2013.05.025Aiming at different data delay requirement in Wireless Sensor Network(WSN), a delay constrained energy efficient routing algorithm for WSN called DCEER is proposed. If this is the only path that has a delay smaller than or equal to the data delay requirement, then the message will be delivered by using the pure sensor-to-sensor path, otherwise the most energy-efficient path in terms of minimum number of forwarding sensors and the minimum total delay is selected, namely, by using sensor to supernodes to sink. Simulation results show that, DCEER has a longer network lifetime and shorted delay, it can balance the energy efficient and delay constrained.
-
Computer Engineering. 2013, 39(5): 123-126,131. https://doi.org/10.3969/j.issn.1000-3428.2013.05.026In order to alleviate the effects of transmission delay and inaccurate receiving time on the time synchronization of the Wireless Sensor Network(WSN), based on the sender-receiver time synchronization algorithm, this paper proposes an improved time synchronization method, which uses the maximum likelihood estimation to estimate the value of each receiving node and to approximate its real value. Then it gets the system clock deviation from the clock deviation of each nodes’ receiving data, obtaining more accurate synchronization time offset. Simulation results show that, without changing the synchronization mechanism, the proposed method can improve the precision of synchronization.
-
Computer Engineering. 2013, 39(5): 127-131. https://doi.org/10.3969/j.issn.1000-3428.2013.05.027Through the analysis of current common radio frequency identification authentication protocol, an authentication protocol based on Kerberos protocol is proposed according to the security and privacy protection with limited computation in Radio Frequency Identification(RFID). By the use of tickets distribution, it can deal with the frequency of mutual authentication, reducing the counts of verification. Analysis and comparison results show that the protocol has a very good improvement for RFID system’s overall performance, particularly in efficiency.
-
Computer Engineering. 2013, 39(5): 132-135. https://doi.org/10.3969/j.issn.1000-3428.2013.05.028Traditional Support Vector Machine(SVM) drops significantly when it is applied to the problem of learning from unbalanced datasets. Based on the study of SVA, a new classifying method which combines the method of under-sampling and cost-sensitive SVM together is proposed. In the first stage, balanced data are set by reconstructing both the majority and the minority class. And in the second stage, cost sensitive SVM is conducted for detection decision function. Receiver Operating Characteristic(ROC) analysis is used to select optimum parameters of cost sensitive SVM in limited grid scope. The proposed model is used for attack detection on recommender systems. Experimental results show that the proposed method can improve the classification accuracy.
-
Computer Engineering. 2013, 39(5): 136-139. https://doi.org/10.3969/j.issn.1000-3428.2013.05.029Aiming at non super-increment sequence knapsack encryption algorithm, this paper proposes two methods for attacking based on lattice. Method 1 can construct three dimensions lattice and utilize LLL algorithm to recover the private key directly with time complexity O(n2); Method 2 can utilize low-density attack to recover its plaintext with high probability and time complexity O(n3lb(max(bi))). Experimental results show that the scheme by Li et al is insecure.
-
Computer Engineering. 2013, 39(5): 140-143,147. https://doi.org/10.3969/j.issn.1000-3428.2013.05.030Because of the low efficiency of Public Key Infrastructure(PKI) authentication mechanism in Grid Security Infrastructure(GSI), this paper designs an authentication model based on Kerberos and Hierarchical ID-based Cryptography(HIBC). Authentication methods between two grid entities in a domain, from two domains and authentication method between PKG are illustrated. Entities in first domain authenticates to each other through Kerberos. Entities in second domain authenticates to each other through HIBC. This model can meet the demand of authentication need in large scale grid. Analysis result shows that the new model is better than previous PKI authentication method in computation and communication. At the same time, it has better security and meets demand of autonomous grid.
-
Computer Engineering. 2013, 39(5): 144-147. https://doi.org/10.3969/j.issn.1000-3428.2013.05.031To improve the problem of the security of Android access permission mechanism, this paper proposes an optimization scheme for access permission security based on Android platform. It divides the Android permission into four categories, acquires categories of different permission combination, quantifies the permission combination security threat values and takes fact that free applications are more likely for malicious applications than paid applications into consideration, for judging application security threat level by application access permission security threat value. Experimental results show that the permission access security mechanism can effectively detect security threat level of applications, judge the degree of application security threat more accurately and achieve the goal of enhancing the security of Android access control.
-
Computer Engineering. 2013, 39(5): 148-151,155. https://doi.org/10.3969/j.issn.1000-3428.2013.05.032To solve the problem of different node trust recommendation priority allocated unreasonably, this paper proposes the Peer-to-Peer(P2P) network trust model based on priority. It designs the method of computing trust value and priority algorithm. The priority algorithm of attenuation with time adopts to compute the node’s trust value which reflects the actual situation of the node. Experimental results show that this model can detect abnormal behavior of nodes, thus effectively avoides abnormal nodes destruction activity. With the increasing of the proportion of simple malicious nodes, conspiracy to discredit nodes and selfish nodes in the network, the request success rate of this model is higher than PeerTrust model and EigenTrust model.
-
Computer Engineering. 2013, 39(5): 152-155. https://doi.org/10.3969/j.issn.1000-3428.2013.05.033To improve the efficiency and veracity of the intrusion detection, this paper presents an intrusion detection algorithm based on Principal Component Analysis(PCA) and K-nearest neighbor algorithm. This algorithm classifies the original attack data ordering by the class of attack, and extracts each class features based on the PCA. It uses the K-nearest neighbor algorithm to classify the observational data. Matlab simulations experiments result shows that this algorithm can effectively decrease the data dimension and enhance the veracity.
-
Computer Engineering. 2013, 39(5): 156-159,164. https://doi.org/10.3969/j.issn.1000-3428.2013.05.034This paper shows that Hong’s efficient certificateless signature scheme is insecure against public key replacement attacks and malicious Private Key Generator(PKG) attacks. Aiming at these problems, the scheme is improved by the means that PKG generates the user’s public key and makes it public. The analysis of security shows that the improved scheme is able to resist public key replacement attacks and malicious PKG attacks. Its security relies on the hardness of the q-Strong Diffie- Hellman(q-SDH) problem and Extended-Inverse-Computational Diffie-Hellman(E-Inv-CDH) problem. Under the random oracle model, the improved scheme is proved to be secure against existential forgery on adaptively chosen message attacks.
-
Computer Engineering. 2013, 39(5): 160-164. https://doi.org/10.3969/j.issn.1000-3428.2013.05.035In order to solve the problems of the nonholonomic mobile robot trajectory tracking, a mobile robot trajectory tracking control method based on sliding mode variable structure control is presented. Based on motion model of mobile robot, a continuous state feedback control law for the angler velocity is proposed to asymptotically reduce the tracking error of the heading angle by using the finite time control method. With the error of the heading angle reaching equilibrium condition at the origin, the other control law for the linear velocity which gives the tracking error of the planar coordinate is designed by using the sliding mode variable structure control theory on basis of backstepping. Experimental result shows that the control laws of this method are tending towards stability in a very short time, the tracking error of the planar coordinate and the error of the heading angle are almost zero.
-
Computer Engineering. 2013, 39(5): 165-168,173. https://doi.org/10.3969/j.issn.1000-3428.2013.05.036Considering the support vector data description model having disadvantages of simple form with only one kernel information and hard to choose the best kernel and its parameters, the multi-kernel one-class classification with a linear combination of multi-kernel is proposed. The multi-kernel support vector data description model which can descript the data distribution boundary in eigenspace more flexibly is built after analysing the space of multi-kernel mapping. The optimal combination kernels’ weight is solved by reduced gradient algorithm. Test dataset which includes abnormal samples is introduced to control and evaluate the description accuracy and expansibility of hyper spherical interface. Experimental results show the method has better learning ability and computing efficiency.
-
Computer Engineering. 2013, 39(5): 169-173. https://doi.org/10.3969/j.issn.1000-3428.2013.05.037In order to solve the Joint Replenishment Problem(JRP) with uncertainty demand, this paper proposes a hybrid Genetic Algorithm(GA) based on improved fuzzy simulation. According to fuzzy set theory, the demands are addressed as the fuzzy variables, using trapezoidal fuzzy number to formulate the expected value model. In order to reach the basic cycle time and the minimal expected value efficiently, a new fuzzy simulation based on the traditional fuzzy simulation and GA are integrated to produce a hybrid GA, and this algorithm is compared with the conclusion of the hybrid GA based on traditional fuzzy simulation. Comparison results show that the expectation cost deviation rate of this algorithm is smaller under the same condition.
-
Computer Engineering. 2013, 39(5): 174-177,182. https://doi.org/10.3969/j.issn.1000-3428.2013.05.038In order to solve the problem of bad performance of a sampling algorithm based on Euclidean distance in a large meteorological dataset with an imbalanced characteristics, this paper proposes a lightning data sampling algorithm based on the Huffman tree. An approach to quickly calculate the number of cluster centers and the number of the samples of each cluster is designed by using the technique for building Huffman tree. According to two values attained, this algorithm can be used to generate non-lightning samples from the large meteorological dataset. Sampling testing on the given set with 27 552 records, results show that this algorithm sampling time is about 16 minutes, not only can reduce the amount of data, and can improve the time performance of this algorithm.
-
Computer Engineering. 2013, 39(5): 178-182. https://doi.org/10.3969/j.issn.1000-3428.2013.05.039A binocular three-dimention reconstruction method combined with Gray coding and phase-shift is presented to achieve a fast high-resolution non-contact binocular three-dimention reconstruction. This method combines Gray code with phase-shift, divides the measured space into sub-spaces with Gray code, makes sure the point in the sub-spaces range in 0~2π phase by using phase-shift image, and combines the phase with the sub-spaces code which makes all the points into a sole code. It matches the points between the left-image and the right-image, if they conform to the matching principle, then match each other in pairs, and use triangular method principle to get the three-dimention coordinates of space points. Experimental results show that this method can quickly realize three-dimention reconstruction, the error is less than 0.351 mm.
-
Computer Engineering. 2013, 39(5): 183-186,191. https://doi.org/10.3969/j.issn.1000-3428.2013.05.040Existing task schedule algorithms for cloud computing are not well to take into account the cost of all the tasks for the pursuit of the shortest completion time. To solve this problem, a task schedule algorithm based on improved particle swarm is proposed in this paper, which uses indirect encoding to encode the resources of each subtask takes, gives decoding way, considers the fitness function about the time and the cost, and establishes the particle position and velocity updating method. Experimental results show that the general assignment finished time and cost of this algorithm are lower than the traditional Particle Swarm Optimization(PSO) algorithm.
-
Computer Engineering. 2013, 39(5): 187-191. https://doi.org/10.3969/j.issn.1000-3428.2013.05.041BP network learning algorithm has the shortcomings of slow convergence speed, easying to fall into local minimum. In order to solve this problem, this paper presents a remote sensing water depth inversion model based on chaotic immune optimization Radial Basis Function(RBF) network. In the model, it introduces the water depth remote sensing inversion principle, the RBF network center vector and weights are optimized by using Chaotic Immune Optimization Algorithm(CIOA), and the CIOA RBF network model are applied in the comparing experiments of remote sensing water depth inversion. Experimental results show that the average absolute error of this model between the inversion water depth and measured water depth is 0.436 7 m, the average relative error is 8.91%, the mean square root error is 0.563 5 m, this model has good nonlinear mapping ability and generalization ability.
-
Computer Engineering. 2013, 39(5): 192-195,199. https://doi.org/10.3969/j.issn.1000-3428.2013.05.042The disadvantage of Gaussian Mixture Model(GMM) is that it requires large amount of computation and its poor real-time detection performance in the process of moving object detection. Aiming at this problem, a moving object detection algorithm based on match times is proposed. It constructs background by creating Gaussian models, counts the number of match times of the observed values of each pixel with the background model, according to the number of match times, divides the detected scene into two areas, such as a static area and a dynamic area. It detects every discontinuous frame for static pixels, does every frame detection for dynamic pixels, and is combined with testing quality and the real-time requirements to study the match threshold value and the interval between frames. Experimental results show that when the static zone area is about 50% for the area of the whole frame, the image detection times of this algorithm for each frame in indoor and outdoor scene are 27 ms and 20 ms, and it can improve the efficiency of detection.
-
Computer Engineering. 2013, 39(5): 196-199. https://doi.org/10.3969/j.issn.1000-3428.2013.05.043Due to frequent decoding operations, the efficiency of optimization is severely reduced when the binary Quantum Genetic Algorithm(QGA) based on qubits measure is applied to the continuous space optimization. To solve this problem, an improved QGA is proposed in this paper. In this algorithm, the search mechanism is built based on Bloch sphere. The individuals are expressed with qubits, the axis of revolution is established with Pauli matrix, and the evolution search is realized with the rotation of qubits in Bloch sphere. In order to avoid premature convergence, the mutation of individuals is achieved with Hadamard gates. Such rotation can make the current qubits approximate the target qubits along with the biggest circle on the Bloch sphere. Example results show that the Integral Time Absolute Error(ITAE) value of this algorithm can meet minimum 4.122 after about 26 step iteration, optimization ability is better than the QGA based on quantum bits Bloch coordinates and Genetic Algorithm(GA) with elite reserving strategy.
-
Computer Engineering. 2013, 39(5): 200-203,208. https://doi.org/10.3969/j.issn.1000-3428.2013.05.044Aiming to improve the performance of standard Particle Swarm Optimization(PSO) algorithm, an improved PSO algorithm based on Multi-swarm and Multi-model cooperative evolution(MSM-PSO) is proposed. The particles are divided into three swarms in the same size, different swarms adapt different evolution models, and three swarms interact and affect each other. Besides, adaptive dynamic inertia weight is adopted in the algorithm, which can maintain diversity of population and reduce the possibility of local minimum. Simulation result shows that this method has better global performance, and higher optimization precision.
-
Computer Engineering. 2013, 39(5): 204-208. https://doi.org/10.3969/j.issn.1000-3428.2013.05.045For script text strokes which contain a large number of discrete points and the additional part, division performance of the existing algorithm is low. In order to solve this problem, this paper proposes a text line segmentation algorithm based on segmented foreground daub and background thinning. This algorithm makes sectional daub on outlook parts, removes the expansion area that length-width ratio does not meet the conditions, gets the text area location, gets the text line segmentation line with image background thinning, gives the weight determination algorithm to solve the context words overlapping problem between the text. Experimental results show that the error rate of this algorithm is only 3.3%, is lower than horizontal projection algorithm, sectional projection algorithm and clustering algorithm. It can make relatively complete segmentation for text lines in 210 pictures, 2 563 text lines.
-
Computer Engineering. 2013, 39(5): 209-211,217. https://doi.org/10.3969/j.issn.1000-3428.2013.05.046It is difficult to detect the weak target in infrared background. In order to solve this problem, this paper proposes an integrated background weak target detection method based on consistency in class. It defines the class consistency function, through the histogram and infrared image segmentation value to make segmentation, uses morphological operation to process images, fills target internal void and connects fracture target, makes multipurpose regional growth, according to the division of several target shape size information to confirm final goal. Experimental results show that the 3 frame image detection times of this method are 0.355 ms, 0.363 ms, 0.335 ms, are better than the Ostu method and average method.
-
Computer Engineering. 2013, 39(5): 212-217. https://doi.org/10.3969/j.issn.1000-3428.2013.05.047This paper surveys Histogram of Oriented Gradient(HOG) and its extension. Combining with the computing step of HOG, this paper discusses its underline idea, the main image features captured by it and its limitations. It discusses several important extensions of HOG, including variable-size HOG, Pyramid of Histogram of Oriented Gradient(PHOG) and analytic dimension reduction HOG. And it also describes the way to speedup the computing of these extensions with integral image. It gives other possible ways to improve HOG and the possible directions to improve the ability of HOG, and makes the comparison of HOG improving methods with measure, complexity, dimension and idea. Several valuable research directions are proposed.
-
Computer Engineering. 2013, 39(5): 218-221. https://doi.org/10.3969/j.issn.1000-3428.2013.05.048In the optimization process of the fruit fly algorithm, the convergence accuracy is unstable because of the initial value choosing suitable or not. In order to solve this problem, this paper proposes a new mixed fruit fly algorithm. The Logistic mapping is integrated into the fruit fly algorithm to do global search for the optimal parameter. It uses the value as the center to do tiny fluctuations to obtain initial value of quadratic optimization, and improve the initial value selection method of fruit fly algorithm. In the function optimization simulation process, compared with the original fruit fly algorithm and Particle Swarm Optimization(PSO) algorithm etc., the convergence accuracy of this mixed fruit fly algorithm has obvious advantages.
-
Computer Engineering. 2013, 39(5): 222-224. https://doi.org/10.3969/j.issn.1000-3428.2013.05.049Traditional evolutionary algorithm sees each chromosome of the population as independent individuals, and doesn’t make fully minning between its internal relations. In order to solve this problem, this paper proposes an evolution algorithm based on chromosome difference and variation attenuation principle. It uses the chromosome index and chromosome structure to do cross operation, gives experience crossover probability formula, set blind date frequency for each chromosome, according to the evolution law, variation attenuation principle is introduced into the mutation operator of evolutionary algorithm. Experimental results show that under 3 functions, the highest average evolution of this algorithm is 78, minimum search success rate is 99%, and is better than basic Genetic Algorithm(GA) and GA introduced division operator.
-
Computer Engineering. 2013, 39(5): 225-229. https://doi.org/10.3969/j.issn.1000-3428.2013.05.050To improve the correct rate of image classification using sparse representation dictionaries, a discriminate dictionary training algorithm based on adaptive steepest descent is proposed. This algorithm uses alternating gradient descent for bi-objective optimization model of discriminate dictionary training. To guarantee the convergence of sparse representation residual and the incoherence of atoms from dictionaries corresponding to different classes and increasing convergence rate, adaptive step size is adopted and the method of calculating the step size is proved. The steps of the algorithm are as following: Fix dictionaries and use current dictionaries and data samples to calculate the steepest descent directions and adaptive step sizes of the sparse representation coefficients. Small coefficients are set to zero according to sparseness constraints. Fix sparse representation coefficients, and use sparse representation coefficients and data samples to calculate the steepest descent direction and adaptive step size of dictionaries. Experimental results of hand-writing recognition show that the correct rate is 96.51%.
-
Computer Engineering. 2013, 39(5): 230-234. https://doi.org/10.3969/j.issn.1000-3428.2013.05.051The protection of copyright property arouses much attention in the present information age. Aiming at the dispute problem caused by the text similarity between some novels, this paper proposes a method based on language model and feature classification, with statistics of coincidences and the proportion of pos to analyze the grammatical collocations and the coincidences. The methods of Principal Component Analysis(PCA) and Random Forest(RF) used to extract characteristics for automatic classification are added into experiments. The result of machine learning shows that the method can effectively identify whether novels exist plagiarism phenomenon.
-
Computer Engineering. 2013, 39(5): 235-242. https://doi.org/10.3969/j.issn.1000-3428.2013.05.052Aiming at the lack of the single perception method of population diversity and premature stagnation, Particle Swarm Optimization(PSO) algorithm based on L norm multi-measures population diversity feedback (PSO-L) is proposed. Position diversity, velocity diversity and self-cognitive diversity using L norm are defined as feedback information of a self-organized particle swarm system, which adjusts the parameters of the proposed algorithm so as to adaptively modify the particles to converge or diverge. The corresponding characteristics of population diversity and the performance of the proposed algorithm on different norms and parameter strategies are performed based on test functions. Moreover, PSO-L, along with other tested algorithms is conducted based on much more benchmark problems. Experimental results show that the proposed method has stronger global search ability and higher accuracy.
-
Computer Engineering. 2013, 39(5): 243-247,252. https://doi.org/10.3969/j.issn.1000-3428.2013.05.053For the structure characteristics usually become instable in traditional graph based image representation methods, a novel image representation and recognition method based on complex network is proposed in this paper. Key points are extracted for an image and an initial complex network is constructed in which nodes correspond to the key points. A novel dynamic evolution process is devised for the initial complex network using the minimum spanning tree decomposition. The features of the networks in different evolution stages are extracted to finally achieve image structural information extraction. This method can simply describe an image by using geometrical feature of the image key points. Experimental results on both classification and clustering demonstrate that the proposed method outperforms the traditional edge weight threshold evolution method and it can describe the structure of images more effectively.
-
Computer Engineering. 2013, 39(5): 248-252. https://doi.org/10.3969/j.issn.1000-3428.2013.05.054Traditional Fourier registration algorithm has big interpolation errors, and has bad image registration effect for scale change larger than 2. In order to solve this problem, this paper proposes a frequency domain image registration algorithm based on quasi-polar coordinate. It uses quasi coordinates discrete Fourier transform close to logarithmic coordinates of discrete Fourier transform, establishes the polar coordinate grid of same angle, when it converts into a logarithmic coordinates, only needs to do a linear interpolation on the pole diameter direction, instead of the direction of bilinear interpolation in polar radius and polar angle. Experimental results show that the registration rate of this algorithm is higher than traditional Fourier registration algorithm.
-
Computer Engineering. 2013, 39(5): 253-256. https://doi.org/10.3969/j.issn.1000-3428.2013.05.055In order to achieve high speed and high quality image scaling in Field Programmable Gate Array(FPGA), this paper proposes an edge adaptive image scaling algorithm based on FPGA. This algorithm uses bilinear interpolation algorithm out of the edge area, uses directional three interpolation algorithm in the edge area, designs the hardware structure and operation logic structure, uses Verilog language to describe, and gives the object code. Experimental results show that this algorithm can gain edge clear scaling image, the complexity of the algorithm is low, after magnifing 2.5 times, the Peak Signal to Noise Ratio(PSNR) of image is 40.76 dB.
-
Computer Engineering. 2013, 39(5): 257-260. https://doi.org/10.3969/j.issn.1000-3428.2013.05.056A medical image segmentation algorithm based on robust feature statistics is proposed in this paper. Users provide seeds, and this paper uses robust feature statistics to describe the features of objects, makes contour smoothly and decreases the effect of noise. It makes contour evolution fast and according to the Sparse Field Method(SFM) to get the outline of objects. Experimental results show that this algorithm gets 73 points in 5 kinds of evaluation indicators for MR abdominal liver segmentation, is better than the region growing algorithm and rapid level set algorithm, liver segmentation time is 123 s, and can make good segmentation of organs and tumors in MR and CT images.
-
Computer Engineering. 2013, 39(5): 261-265. https://doi.org/10.3969/j.issn.1000-3428.2013.05.057The images filmed by digital devices are always coupled with perspective distortions, which result in a failure of the layout processing and recognition. An effective perspective distortion correction method is presented to resolve the perspective distortion correction in cuboid’s surface. A vanishing line is determined by two pairs of parallel lines which are four edges of cuboid’s surface. The vanishing line is used to determine the direction and value of perspective distortion correction. An image can be obtained which is same as original cuboid’s surface except the size. Experimental results show that this method is accurately and effectively for perspective distortion correction in cuboid’s surface.
-
Computer Engineering. 2013, 39(5): 266-269. https://doi.org/10.3969/j.issn.1000-3428.2013.05.058A new kind of cotton image segmentation algorithm based on Support Vector Machine(SVM) is proposed. The cotton image is classified into the target and the background. The sample pixel value is extracted from the two categories under OHTA color space. These samples are trained with category information by SVM. Otsu method is used to deal with the image. SVM classifier is trained to segment the cotton image after pretreatment, and the noise is removed by region label. Experimental results show that this method can segment cotton image with the complex background, and the accuracy of segmentation cotton images is as high as 92.3%. Its classify speed is better than directly using SVM to segment the image. The accuracy and stability are better than threshold segmentation method.
-
Computer Engineering. 2013, 39(5): 270-272,276. https://doi.org/10.3969/j.issn.1000-3428.2013.05.059In order to satisfy the requirement of the traffic monitoring in the road which is needed to deploy quickly, also reduce costs, this paper proposes a solution to integrate the GPRS network communication with low-cost image acquisition device. To select the MC9S12XS128 microcontroller as the core of the data acquisition device, the OV7620 data video as the image sensor, and the EM310 wireless communication module as the GPRS communication module, the system network establishes the connection between data acquisition device and monitoring center by a server which has a public IP. This system has the advantages of low-cost, quick deployment and wide monitoring range, which can satisfy the application requirement.
-
Computer Engineering. 2013, 39(5): 273-276. https://doi.org/10.3969/j.issn.1000-3428.2013.05.060Aiming at the clock is asynchronous between the detection nodes in Wireless Sensor Network(WSN), the Peer-to-Peer Time Synchronization Algorithm(PTPTSA) is proposed, which is subnet synchronous solution. The PTPTSA puts the nodes clock synchronize to the base station, and uses the linear regression to fit the clock offset curve, in order to determine the clock offset rate of the nodes, so compensating the accumulative time synchronization error, realizing the long time synchronization between the nodes. Experimental results show that while the clock compensation is carried out every 6 minutes, the practically synchronization error between nodes is within 10 microseconds per second, and the cumulative error is less than 1 millisecond, so the algorithm meets the requirement of water supply pipelines leak detection.
-
Computer Engineering. 2013, 39(5): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2013.05.061For now, some researches on the detection of voice authenticity are almost based on the recording material content and background noise, not involves the essence of recording material storage, resulting in poor authenticity detection results of the voice signal. According to the essence of digital storage and the stochastic resonance theory, a test method for voice signal authenticity is proposed. It can identify the edit points from the faint change of magnetism/charge. Many time domain simulation experiments show that this method has higher identification percentage than other methods, and can judge the location of the voice edit points.
-
Computer Engineering. 2013, 39(5): 280-283. https://doi.org/10.3969/j.issn.1000-3428.2013.05.062In order to improve the accuracy of the speech recognition, this paper starts from text analysis module and chooses some words, with easy wrong pronunciation, for the Chinese text corpus. These words are recorded by one male and one female speaker who are the first batch of Xinjiang Uyghur students graduated from the bilingual class. The comparison of experimental is done using the IFLYTEK mandarin standard male and female voice. The features of Chinese pronunciations of Uyghur people are analyzed from the acoustic point of view, and some of the rules are summarized. By measuring the acoustic parameters, the presence of errors in pronunciation is confirmed and the reasons are analyzed. Experimental basis for the research of speech recognition is provided.
-
Computer Engineering. 2013, 39(5): 284-287,292. https://doi.org/10.3969/j.issn.1000-3428.2013.05.063Aiming at the porting of embedded Real-time Operating System(RTOS) TOPPERS/ASP is difficult, this paper researches on the porting process, presents the features and kernel structure of embedded RTOS TOPPERS/ASP. The necessary work and key points of porting TOPPERS/ASP are presented and verified in the porting for one new processor architecture, Freescale MCF56F8367 microcontroller. The work can be a guideline for porting TOPPERS/ASP for new processor architecture under commercial integrated development environment.
-
Computer Engineering. 2013, 39(5): 288-292. https://doi.org/10.3969/j.issn.1000-3428.2013.05.064In Power Line Communication(PLC) G3 physical layer protocol, for the problem of large resource consume on realization of Field Programmable Gate Array(FPGA), an improved algorithm suited for FPGA implementation is proposed, which uses the quantification of P signal saves in local, the absolute normalization method of Q(n) and Singular Value Decomposition (SVD). The analysis and comparison between the result of FPGA implementation and algorithm simulation show that the improved algorithm can accurately estimate the channel, and the FPGA implementation is reasonable.
-
Computer Engineering. 2013, 39(5): 293-296. https://doi.org/10.3969/j.issn.1000-3428.2013.05.065In order to overcome the shortcoming that Optimal Sub Pattern Assignment(OSPA) only measures the distance, Optimal Sub Pattern Assignment Probability(OSPAP) metric standard is proposed. By introducing the probability, it measures tracking algorithm performance by computing elementary probability and label error probability between the ground truth tracks and the estimated tracks. It is impossible to obtain the ground truth tracks in the applications but the probability is easy to be got in the multi-target tracking algorithms based on the probability. Experimental result shows the measurement data obtained from this standard is accordance with the actual situation, and it can reflect the performance of probability tracking algorithm in actual tracking system in real-time.
-
Computer Engineering. 2013, 39(5): 297-300. https://doi.org/10.3969/j.issn.1000-3428.2013.05.066In order to make the functionality and performance test of all parts of the new planes accurate, and give assistance to the designers to maximize the test of each moment, the flight simulation platform proposes demand which needs higher simulation accuracy. It includes completing the real-time solver of flight simulation model, simultaneously collecting and storing 5 000 simulation data in 1 ms simulation cycle. This work introduces ping-pang cache storage algorithm and two kinds of real-time data acquisition algorithm which are compact acquisition and choose acquisition. And in this work, the millisecond level simulation cycles, huge amounts of high-speed real-time data acquisition and storage is solved.
-
Computer Engineering. 2013, 39(5): 301-304. https://doi.org/10.3969/j.issn.1000-3428.2013.05.067This paper presents a channel estimator based on multi-core platform for Long Term Evolution(LTE) downlink. This design partitions task into various sub tasks, and then maps subtasks onto 13 different cores by the relative inter-core communication traffic. The integration usage of shared memory and NoC message transfer are 2 ways for inter-core communication, as to realize multi-core collaborative work. By using the extended register file, SIMD data path characteristics and balanced single core computation load. Performance analysis result shows that this channel estimator can achieve a throughput of 678 Mb/s.
-
Computer Engineering. 2013, 39(5): 305-308. https://doi.org/10.3969/j.issn.1000-3428.2013.05.068This paper presents a complete and automatic method to resolve the relationship between bitstream and circuit configuration of Xilinx Field Programmable Gate Array(FPGA). Including method for analyzing relationship between single Programmable Point(PP) and bitstream data, and method for analyzing mass scripts based on distributed architecture. Using circuit recovering method, a Bit2NCD tool is developed, which can reverse the bitstream file to Native Circuit Description(NCD) netlist file. A demonstration on Spartan2 chip verifies the circuit recovering method is feasible, and the configuration data is correct and complete.
-
Computer Engineering. 2013, 39(5): 309-313. https://doi.org/10.3969/j.issn.1000-3428.2013.05.069Aiming at the purpose of transmitting the audio and video data, as well as the position information to the command center for the command crew to process the emergency cases, this paper designs a portable mobile terminal system based on embedded Linux system. The processing chip Hi3512 is used as the core of the system to realize the work of processing the audio and video data information. Those data as well as the position information are transmitted by the 3G wireless communication system. The test of the whole system shows that the audio and video transmission delay is quietly low and the position information is accuracy. It reaches the require of the whole project.
-
Computer Engineering. 2013, 39(5): 314-317. https://doi.org/10.3969/j.issn.1000-3428.2013.05.070Due to the initial alignment declination and odometer coefficient error, navigation errors are increased with time. To solve this problem, the map matching algorithm is used to precisely match the dead reckoning to compensate the vehicles heading deviation angle and odometer coefficient error by positioning error. The error feedback iterative method is used to compensate for correction. Study result shows that the odometer coefficient error and dynamic alignment accuracy are mainly affected by the vehicles displacement and positioning accuracy, the odometer coefficient error is significantly lower and the accuracy of alignment can reach minute level after five iterative calculations, which can also better inhibit the gyro drift on navigation deviations impact.
-
Computer Engineering. 2013, 39(5): 318-321. https://doi.org/10.3969/j.issn.1000-3428.2013.05.071Facing the problem of synthesizes performance formal verification for complex information system, this paper uses the data transmission system as example and applies a new property verification method based on improved Markov decision process to verify the performance of the system. A new more expressive temporal logic is used to describe system model properties on the basis of all kinds of continuous stochastic logic variants. By using automata to express logic path formula, the corresponding algorithm is described based on product model which realizes the simultaneous evolution of the model and the automata. Example result verifies the method can effectively expand the application scope of the model checking technology.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
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
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