15 February 2014, Volume 40 Issue 2
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Computer Engineering. 2014, 40(2): 1-5. https://doi.org/10.3969/j.issn.1000-3428.2014.02.001
This paper brings the idea of MapReduce parallel processing to high energy physics data analysis, proposes a high energy physics data analysis system based on Hadoop framework. It significantly reduces the number of events that need to do further analysis by 2~3 classes by establishing an event TAG information database, which reduces the I/O volume and improves the efficiency of data analysis jobs. It designs proper MapReduce libs that fit for the ROOT framework to do things such as data splitting, event fetching and result merging by using event pre-selection model based on TAG information and MapReduce model of event analysis. A real system is implemented on BESIII experiment, an 8-nodes cluster is used for data analysis system test, the test result shows that the system shortens the data analyzing time by 23% of 4×106 event, and event number of concurrence analysis per second is higher than cluster nodes when adding more worker nodes, which explains that the case analysis cluster has a good scalability.
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Computer Engineering. 2014, 40(2): 6-10. https://doi.org/10.3969/j.issn.1000-3428.2014.02.0002
In order to improve the energy utilization rate in data center on the premise of guaranteeing Quality of Service(QoS), this paper proposes a data center Virtual Machine(VM) adaptive energy-saving mechanism based on the prediction of users’ access quantity, and researches periodicity of users’ visit by Adaptive Holt-Winters(AHW) prediction method. It can adaptively adjust the number of VM according to user visits to improve the utilization rate of VM and achieve the purpose of reducing data center energy consumption. Simulation experimental results show that the Mean Absolute Percentage Error(MAPE) of AHW method is 22.46% and the utilization rate of VM in data center is 97.88% which is promoted by 37.19% compared with the former utilization without using this adaptive energy-saving mechanism, and proves that this energy-saving mechanism has good statistical properties and stability for forecasting the periodic user access, it can be better satisfy the needs of data center energy-efficient.
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Computer Engineering. 2014, 40(2): 11-15. https://doi.org/10.3969/j.issn.1000-3428.2014.02.003
In the path planning with endpoint directional constraints, traditional A* algorithm is inefficient due to lack of directional guide. To solve this problem, the dynamic guiding A* algorithm is proposed, which introduces dynamic guide points on the basis of the A* algorithm. The dynamic guiding strategies are given, and then a guiding points generation method is proposed. At the same time, a new evaluation function is designed, and the switch method of the guide points is described. Experimental results show that compared with traditional A* algorithm, this new method can find the resultant path which goes from the specific direction of the start point to the fixed direction of the target efficiently as well by setting the proper parameters, while the planning speed can be improved by more than 10 times.
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Computer Engineering. 2014, 40(2): 16-20. https://doi.org/10.3969/j.issn.1000-3428.2014.02.004
In the new tiered mobile network architecture, this paper proposes a triangle-grid orbit movement and transmission control model. Based on the model, it designs a movement policy of F-connect and proposes a dynamic two-anchor nodes localization algorithm to compute area triangle-grid nodes map. By combining the map and EHCC-communication lemma, it controls the F-collect to collect the data of S. From the simulation, it obviously indicates that this project movement control strategy suits extremely the large-scale Wireless Sensor Networks(WSN). When the network scale achieves certain degree, it can show the superior performance in data collection. The proposed model provides a good solution of the problem on tiered mobile network of instable communication and high-fraction of event loss.
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Computer Engineering. 2014, 40(2): 21-25,30. https://doi.org/10.3969/j.issn.1000-3428.2014.02.005
Aiming at the problem of sending redundant in opportunistic routing protocols based on wireless Mesh network coding, this paper proposes a wireless Mesh network coding opportunistic routing protocol based on dynamic redundancy control, and the transmitting process of this class of protocols is modeled and analyzed by linear space theory. It uses null space acknowledgement to evaluate the amount of update information, and dynamically adjusts node sending redundancy according to total update information. In addition, a forwarding priority scheduling mechanism is introduced to avoid duplicate transmissions of the same linear space from different forwarding nodes. Simulation experimental results show that the protocol improves 30%~100% network throughout and 20%~45% normalized transmission cost compared with MORE protocol.
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Computer Engineering. 2014, 40(2): 26-30. https://doi.org/10.3969/j.issn.1000-3428.2014.02.006
In order to achieve the deterministic transmission of multimedia data in Ethernet for Plant Automation(EPA), this paper analyzes the feasibility of the multimedia data transmit on EPA communication macro cycle and the principle of IP fragment reassembly based on the study of EPA communication scheduling principle. It designs transmission scheduling model of multimedia data in cycle time slice, and a reassemble algorithm of the slice datagram based on linked list insertion method. Aiming at the problem that the most multimedia device can not integrate EPA protocol stack on the market and participate in schedule EPA field layer, it constructs EPA network test platform of accessing multimedia data. Experimental results show that with the case of no disturbance to control data, multimedia data transmission delay based on EPA is 30 ms~36 ms, it can satisfy the acceptable delay-time of 130 ms, delay jitter less than 4 ms, the image is clear and smooth, and the feasibility of multimedia data deterministic transmit on EPA is examined.
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Computer Engineering. 2014, 40(2): 31-34,38. https://doi.org/10.3969/j.issn.1000-3428.2014.02.007The emergence of distributed Web crawl largely expands the scale of related Web information. Since PageRank needs to process the topology of entire existed page set, the limitation of CPU, I/O and memory becomes the big issue when it confronts the data in TB or PB level. Aiming at these problems, this paper proposes a parallel PageRank algorithm based on MapReduce. In a certain iteration of algorithm, it processes the files containing the topology of Web page graph by Map function and calculates the pages’ scores by Reduce function. Using the global Web page score as convergence to control iterations and get more precise Web page sorting result. Experimental result shows that the improved algorithm has better clustering performance and faster execution speed on the basis of keeping the overall Web page sorting accuracy of single machine PageRank algorithm.
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Computer Engineering. 2014, 40(2): 35-38. https://doi.org/10.3969/j.issn.1000-3428.2014.02.008When solving strong plan, through using hierarchical states, it can sharply reduce the scale of the problem, boost search, and it can get the solution of shorter path. But existing hierarchy algorithms are still complex in some extent, and when the number of states is big, it costs large. Based on the ideal of hierarchy, it designs a fast hierarchy algorithm. It uses bidirectional chain graph to save data. In hierarchy, it directly modifies traversed state-action pair, and according to the modified results to make decision directly. With that, only one previous hierarchy is needed to judge rather than all hierarchical states. And it avoids searching the state transition of unnecessary and avoids repeat searching on necessary state transition. Experimental result shows that this algorithm runs more quickly than similar algorithms such as the matrix multiplication hierarchy algorithm.
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Computer Engineering. 2014, 40(2): 39-43,47. https://doi.org/10.3969/j.issn.1000-3428.2014.02.009The high energy physics experiment of Beijing Electron Spectrum III(BESIII) produces experimental data of the magnitude of PB, which becomes an immense challenge for the existing computing resources. In order to solve the bottleneck problem, the distributed computing is considered as one of the most realistic solutions. According to the need, the metadata management is studied as an important component of BESIII distributed computing. The metadata model is designed and then metadata management system is implemented by using the catalog service of the DIRAC middleware. It adopts new techniques such as tree-like directory structure, dynamic construction of data file names and virtual datasets etc to effectively organize and store all kinds of metadata, and provides the mapping among inquiry requests, logical files and physical files. It uses the digital certificate and OpenSSL protocol to guarantee the system security. The system is set up and applied to the data processing and analysis. Test results show that its query time is just 0.3 s when it is accessed by 300 clients at the same time, so its performance meets the requirements of the BESIII experiment.
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Computer Engineering. 2014, 40(2): 44-47. https://doi.org/10.3969/j.issn.1000-3428.2014.02.010Task scheduling is a core issue in grid computing. In view of the load imbalance problem caused by the high heterogeneity of grid resources and tasks, a Balanced Online Scheduling(BOS) algorithm is proposed. The algorithm comprehensively considers task arrival frequencies, task size, task completion time and task execution moment. A task’s turnaround time consists of two parts, such as waiting time and executing time. For a long task, executing time accounts for a greater proportion, while for a short task, waiting time is more critical. Thus, different policies are used for short and long tasks. Experimental results show that compared with MCT algorithm, BOS shortens makespan, average task turnaround time, and average stretch. Resource utilization and load balance factor are improved.
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Computer Engineering. 2014, 40(2): 48-51,57. https://doi.org/10.3969/j.issn.1000-3428.2014.02.011After a discussion of the low efficiency task allocation and load imbalance problem in parallel computing of remote sensing image, this paper gives the multi-task distribution model, and proposes a compute nodes’ priority-based task distribution algorithm, which is in comprehensive consideration of load and performance of compute nodes. It collects real-time information on each node when the task is assigned. According to the formula to calculate the priority of each computing node and in accordance with the priority level of assign tasks, under the premise of load balancing, this algorithm can assign task reasonable to computer nodes. Evaluation result shows that this algorithm can process task allocation in reasonable time. The distribution of the tasks becomes more reasonable and uniform, and behaves better than round-robin scheduling algorithm by about 2 times when the number of tasks increases.
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Computer Engineering. 2014, 40(2): 52-57. https://doi.org/10.3969/j.issn.1000-3428.2014.02.012In order to solve the problem that the existing trust models for internetware lack the analysis and prediction for the trust cooperation process of the software entities, this paper researches the trust collaboration relation of software entities by using Bayesian game. It points out the security problem of internetware, puts forward an evolution model of internetware, and models for the trust cooperation process of the software entities by Bayesian game. It uses Harsanyi conversion to get the Bayesian Nash Equilibrium(BNE), and predicts for the result of the cooperation game. In order to promote the cooperation of the software entities, the relevant parameters in the game model is analyzed and discussed through the experiments. Result shows that it can improve the overall security of the internetware system.
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Computer Engineering. 2014, 40(2): 58-61. https://doi.org/10.3969/j.issn.1000-3428.2014.02.013The distributed text retrieval system is difficult to take both high retrieval efficiency and low cost of index maintenance into account, so this paper proposes a Text Retrieval Model based on Counting Bloom Filter(CBFTRM) to solve the problems above. This model divides the physical node into the data node and the index node, both of which are overlaid with structured P2P network. Each data node is responsible for storing documents, and maintaining the inverted index of the documents. It also transmits the values of Counting Bloom Filter(CBF) which are computed by the inverted index’s keywords to the corresponding index node. Each index node builds a search tree and maintains it when the tree’s leaf node changes. The search tree is built by leaf nodes with the data node’s character(including their counting bloom filter’s value), and its internal nodes with the result computed by the values of counting bloom filter. Simulation result shows that this model locates the document faster, and has less traffic doing index maintenance and higher precision.
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Computer Engineering. 2014, 40(2): 62-66. https://doi.org/10.3969/j.issn.1000-3428.2014.02.014Through using Deep Propagation(DP) algorithm, which is the techniques of inclusion based pointer analysis on-line optimization technology, to optimize the technology of cycle elimination based on invocation graph context-sensitive pointer analysis, and then puts forward a new context-sensitive DP algorithm. It initializes constraint graph, explores and merges ring, executes difference propagation and circulates processing complex constraints in the diagram, until all the point-to set of all nodes no longer change after executive vertical transmission routines for once, then gets mapping of each node in the graph to the point-to set. Using the CIL tool for experiment, results show that the proposed algorithm has higher time efficiency when analyzing the same large scale program compared with cycle elimination technology.
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Computer Engineering. 2014, 40(2): 67-70,76. https://doi.org/10.3969/j.issn.1000-3428.2014.02.015Program dependence relation analysis is an important method of testing, maintaining, analyzing and optimizing program, especially parallel extraction. The dependence of rungs caused by definition and reference has the same variable and the parallelism of sequential rungs in Ladder Diagram(LD). Aiming at the problem, a method is proposed to extract LD diagram rung data flow and data dependence relation by constructing data dependence relation directed diagram, recognize LD diagram parallel rung in data dependence relation directed diagram. Experimental result shows that the LD diagram scan time is shorten to 50%~20% by concurrent extraction.
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Computer Engineering. 2014, 40(2): 71-76. https://doi.org/10.3969/j.issn.1000-3428.2014.02.016In the 64-bit architecture of the CPU, the word length extends from 32 bit to 64 bit, and the data which CPU can process each time also increases to 64 bit. Few studies are performed to date to answer what influences 64-bit systems have on the compression and decompression of inverted index, which is the primary data structure in search engines. Some compression algorithms of posting lists work well on 32-bit machines, but are inefficient on 64-bit machines. This paper proposes three word-aligned compression algorithms on 64-bit system, namely, SimpleX64-16, SimpleX64-32 and SimpleX64-64. It adopts more modes and optimizes each mode for each algorithm. Experiments based on inverted index of GOV2 and ClueWeb09B show that those algorithms can improve compression ratio by 2.5% and decompression rate by 14.5%, compared with the traditional 32-bit word-aligned compression algorithms, on 64-bit machines.
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Computer Engineering. 2014, 40(2): 77-80,85. https://doi.org/10.3969/j.issn.1000-3428.2014.02.017Due to the high complexity and diversity of integrated computer system, it is an urgent problem in embedded weapon systems field that how to simulate integrated computer system and do testing on this basis. Aiming at the problem, this paper proposes an all-digital simulation test platform for integrated computer system. It designs the test cases to generate test scripts on the model-driven test module, and implements the test work scheduling and control by the test console and test agent. By this way to execute test command on the simulation platform, it reaches the aim to test the tested program on the simulation platform, and gives the test strategy for various types of test to prove the effectiveness of this platform.
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Computer Engineering. 2014, 40(2): 81-85. https://doi.org/10.3969/j.issn.1000-3428.2014.02.018As technology scales down, more and more cores are integrated into single chip with larger and larger cache memories. Recently, Non-uniform Cache Architecture(NUCA) is proposed to mitigate the increasing wire delay for cache memories in multi-core systems. High performance block migration policy is crucial for the overall performance of the memory subsystem in multi-core systems. The block access information is not considered in the design of block migration strategy of Dynamic NUCA(D-NUCA) which can lead to the jitter of blocks among different cache banks, result in even longer access latency. Aiming at the lack of efficient block migration strategy, this paper proposes a Reuse-aware Block Migration(RABM) for D-NUCA. Through exploiting the historical block migration information as the hint, the proposed migration strategy can effectively improve the performance of D-NUCA and reduce caching system power consumption. Full system simulation result based on PARSEC benchmark test program show that D-NUCA based on RABM improves the Instruction per Cycle(IPC) by 9.6% on average, and reduces on-chip cache system power consumption by 14% on average compared with D-NUCA.
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Computer Engineering. 2014, 40(2): 86-91,96. https://doi.org/10.3969/j.issn.1000-3428.2014.02.019The complexity of concurrent program verification is uncertain in running, therefore it is difficult to make clear the relation- ship of the verification contents and the verification aim. To resolve the problem, this paper proposes a reliability verification method for concurrent program based on separation logic. It describes an execution diagram about the relation and its statements, turns the logic expression of program property into the logic combination expression of variable concurrent statements sequence, and makes property expression associated with concurrent program statements. It confirms statement execution sequence and logic expression according to logic combination expression, verifies programs according to the expression based on separation logic and temporary logic, and modifies concurrent program by verification result. The Bank counter business function module is implemented based on the proposed verification method, and it shows that the method is effective.
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Computer Engineering. 2014, 40(2): 92-96. https://doi.org/10.3969/j.issn.1000-3428.2014.02.020Aiming at the problems of the increasingly serious environmental pollution and the limitations of the traditional wired monitoring water quality, this paper proposes a water quality monitoring system based on Wireless Sensor Network(WSN), including the design of wireless sensor node, the data acquisition of the monitoring water quality parameters through the wireless sensor nodes, and the data are collected through Zigbee network for collection and processing, and through the General Packet Radio Service(GPRS) network, they are promptly transmitted to the remote supervision departments, so as to realize the real-time, effective supervision and management on river water quality situation. The hardware and software circuit design of the system is introduced in detail, and the system is debugged. Experimental results show that the design system can be well applied to water quality monitoring.
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Computer Engineering. 2014, 40(2): 97-101. https://doi.org/10.3969/j.issn.1000-3428.2014.02.021In the GROUP protocol, the cluster heads’ distribution is irregular and the data path is not the best, so it is necessary to design a better routing protocol. Based on the distance comparison becoming zero method, a grid clustering routing protocol is designed, which chooses the most appropriate neighbor cluster header to carry on the data transmission to guarantee stable data transmission and balanced distribution of energy cost of node inside the cluster, and simulation comparison is completed between GROUP agreement and the improved grid clustering routing protocol. Synthetical comparison and analysis results show that the proposed protocol has obvious ascendant in the complexity, the energy cost of constructing grid clustering and routing delay, especially when the network has many nodes.
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Computer Engineering. 2014, 40(2): 102-105,109. https://doi.org/10.3969/j.issn.1000-3428.2014.02.022A new modeling and Digital Pre-distortion(DPD) method named as Parallel GMP-SCT-CIMT(PGSC) is proposed because of the strong memory effect characteristics of broadband power amplifier. The new behavioral model of power amplifier and pre-distorter are constructed of Generalized Memory Polynomial(GMP), Specific Cross Terms(SCT) and Cross Items between Memory Times(CIMT). A test platform is built to verify the accuracy and linear effect of the method. Experimental results show that compared with the PMEC method, the PGSC method shows an average Normalized Mean Square Error(NMSE) improvement of 2.1 dB in behavioral modeling, and reduces the third-order ACPR of output signal by 4.94/2.03 dB in DPD application. Compared with the GMP method, the PGSC method achieves higher model accuracy and better linear effect just using approximately 73% of coefficients.
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Computer Engineering. 2014, 40(2): 106-109. https://doi.org/10.3969/j.issn.1000-3428.2014.02.023As the sticking point of probabilistic packet marking techniques, marking probability has important influence over the convergence, weakest link, and node burden. Based on the analysis of the existing algorithm’s merit and demrit, this paper proposes a Layered Mixed Probabilistic Packet Marking(LMPPM) algorithm combined with the cluster structure of Wireless Sensor Network(WSN). The distance of nodes’ marking probability is enlarged and the reaching probability of nodes of advanced position is increased by amplifying the relative distance of nodes. Analysis result shows that LMPPM algorithm is better than Basic Probabilistic Packet Marking(BPPM) algorithm in convergence and weakest link respects, and better than Adapt Probabilistic Packet Marking(APPM) algorithm in node burden respect, which can realize whole optimization in WSN resource constraint conditions.
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Computer Engineering. 2014, 40(2): 110-113,118. https://doi.org/10.3969/j.issn.1000-3428.2014.02.024The fault detection in large scale Wireless Sensor Network(WSN) has low performance in accuracy and can bring high communication load. Considering temporal and spatial correlation in WSN, a novel cluster-based sensor fault detection algorithm is proposed. The algorithm provides a way to identify faulty sensors by finding normal cluster heads and using its as reference to infer detection statuses of its neighbors. Performance analysis and experimental results show that the algorithm has good fault detection ability and lower communication load, it can achieve over 98% fault detection accuracy and keep lower energy consumption even in the case of smaller neighboring nodes and higher node’s failure ratio.
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Computer Engineering. 2014, 40(2): 114-118. https://doi.org/10.3969/j.issn.1000-3428.2014.02.025Most of the existing studies about Opportunistic Spectrum Access(OSA) under the power constraint use the completely observable Markov Decision Process(MDP) for environmental modeling to improve the single Medium Access Control(MAC) layer or physical layer indicators. Due to the limitations of the perceived equipment, it is difficult to ensure that users can obtain the environment’s fully information. To solve this problem, this paper proposes a cross-layer optimization OSA design based on Partially Observable MDP(POMDP) and Sarsa(λ). The secondary user’s spectrum sensing and access problem subject to the power constraint is modeled as a POMDP by combining the medium access control layer and the physical layer. The POMDP is converted to the Belief state MDP(BMDP). The Sarsa(λ) algorithm is used to achieve the solution of BMDP model. Simulation results show that the proposed design under the power constraint reduces the effective transmission capacity, throughput and spectrum utilization by 9%, 7% and 3% compared with Q-MDP scheme, reduces the bit error rate by 20% compared with PBVI-POMDP scheme, and improves the bit error rate by 16% compared with Q-MDP scheme.
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Computer Engineering. 2014, 40(2): 119-122,133. https://doi.org/10.3969/j.issn.1000-3428.2014.02.026Research Online Mobile is one of many applications for Duckling, considering of its low bandwidth, long delays and frequent disconnection under mobile communication environment, it leads to conflicts easily when multiple users operating on the same data, so conflict resolution and data synchronization are the key issues in Research Online Mobile. Aiming at this problem, this paper proposes a data synchronization strategy based on conflict resolution. It presents the overall framework and the strategy of data synchronization, and the conflict resolution process. Moreover, according to the scenes of conflict, the pushing model is established based on the user’s classification and the priority. It creates a protocol on the Android platform and carries out experiments taking team contacts in Research Online Mobile as an example. The results show that this strategy can effectively save the bandwidth, improve the synchronization efficiency and has good user experience.
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Computer Engineering. 2014, 40(2): 123-127,139. https://doi.org/10.3969/j.issn.1000-3428.2014.02.027In Cognitive Radio Network(CRN), it exists the secure problem that adversaries emulate the characteristics of Primary User(PU) transmissions in order to occupy the authentic spectrum, and other Cognitive User(CU) mislead the existence of PU. Aiming at this problem, a secure sensing mechanism based on helper nodes is proposed. This mechanism relies on link signatures and cryptographic mechanisms to identify the PU activity. The corresponding fusion algorithm for this scheme is also proposed. The proposed algorithm can identify such adversaries efficiently without any modification to Primary Network(PN), and acquire robust results by utilizing sensing data of trust nodes. The simulation results show that this algorithm can achieve better detection performance in hostile environment than K rank, And and Or algorithm.
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Computer Engineering. 2014, 40(2): 128-133. https://doi.org/10.3969/j.issn.1000-3428.2014.02.028The Synthesis of Linear Shift Register(LSR) with error tolerance is an important problem in the analysis of stream cipher. This paper constructs a homogenous key equation which is described by homogenous ideal of . It shows that the Homogenous key module equation can be used to solve the synthesis problem of the LSR sequence. By means of a fast computation of Gr?bner basis of homogenous polynomial ideal with two variables, the paper finds an efficient algorithm to solve the Homogenous key module equation. It gives a theorem to show the error tolerance of the algorithm. Results show that the success rate of the algorithm has a linear relationship with the complexity of the sequence, for a sequence with length of 1 000 and complexity of 65, the success rate of the algorithm is up to 86.6% at an error code rate of 10–3.
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Computer Engineering. 2014, 40(2): 134-139. https://doi.org/10.3969/j.issn.1000-3428.2014.02.029This paper proposes a two-party key policy attribute-based key agreement protocol on the basis of attribute based encryption scheme. It discusses some properties and potential applications of key policy attribute based key agreement protocol with the characteristics of fuzzy identification, key policy is access tree structure. It analyzes the security attributes of the protocol and gives the rigorous proof of security. Results show that, comparing with previous protocols, the new protocol achieves more complex access structure and is proved secure in the standard model under the Decisional Bilinear Diffie-Hellman(DBDH) assumption.
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Computer Engineering. 2014, 40(2): 140-143,147. https://doi.org/10.3969/j.issn.1000-3428.2014.02.030To solve the problem that mutual authentication is lacked in many existing Password-authenticated Key Exchange(PAKE) protocol, this paper proposes an Universally Composable(UC) secure Mutual Password-authenticated Key Exchange(MPAKE) protocol. An ideal function of PAKE protocol with mutual authentication is defined, the mutual authentication between entities is described explicitly in the defined function, and a new protocol which achieves the ideal function is constructed based on the Joint state UC(JUC) model. So the shared parameters can be used to facilitate the protocol between entities. The new protocol can realize mutual authentication based on password and a session key can also be negotiated. The emulator and its operations are constructed, and its indistinguishability is analyzed. Thus the constructed new PAKE protocol with mutual authentication is proved to be UC secure and simple structure, and the security of protocol is realized when running in parallel in any multi-party environment.
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Computer Engineering. 2014, 40(2): 144-147. https://doi.org/10.3969/j.issn.1000-3428.2014.02.031Aiming at the problem of JPEG steganography detection, a universal steganalysis approach is proposed based on DCT coefficient distribution model. A better bi-parameter Symmetric ?-stable(S?S) model is built according to the statistical regular of the DCT coefficient distribution. The model parameters, estimated by solving a discrete function parameter optimization problem using advanced genetic algorithm, are employed to be the steganalytic features and calibrated to improve its sensibility. A feature-matched one-class classifier with linear computation complexity is designed. Experimental results show that the method is reliable in steganalysis for all kinds of JPEG steganography. When the embedding rate is 25%, its mean detection rate achieves 76.1%, which is at least 5.5% higher than the traditional model-based steganalysis methods, it has high detection performance.
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Computer Engineering. 2014, 40(2): 148-152. https://doi.org/10.3969/j.issn.1000-3428.2014.02.032Secure two-party vector dominance statistic is a special secure multi-party computation problem, which can be used by two parties to get the number of ai>bi without leaking their private vector information. The protocol security and efficiency is very lower in existing secure two-party vector dominance statistic protocol rely on oblivious third party. To address this situation, this paper proposes a new secure two-party vector dominance statistic protocol without oblivious third party based on homomorphic encryption and vector cross protocol in semi-honest model. Theoretical analysis shows that this protocol doesn’t include oblivious third party so that its security is improved, and only needs two rounds communication that leads to the reduction of communication complexity. The performance of ranking protocol is improved significantly when the new secure two-party vector dominance statistic protocol is applied in secure components sum of two vectors ranking.
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Computer Engineering. 2014, 40(2): 153-157. https://doi.org/10.3969/j.issn.1000-3428.2014.02.033According to the problem of multi-robot intricate and multi-robot collaboration unstable for remote monitoring system of multi-mobile robot, a system architecture based on multi-Agent technology can be established to optimize the man-machine intelligence allocation and to give a clear description of the various components of the system. By the analysis of the physical structure of the system, the architecture of hierarchical system based on share control mode of multi-Agent is proposed and a mixed communication model of multi-Agent combining the blackboard architecture and peer-to-peer structure is designed. According to the characteristics of the teleoperation system, a hybrid Agent architecture is designed. An example of the realization of the Agent is given, and an experiment that multi-operator keep robots controlled in line is designed to verify the effectiveness of the hybrid Agent architecture.
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Computer Engineering. 2014, 40(2): 158-161. https://doi.org/10.3969/j.issn.1000-3428.2014.02.034Road detection is an important part of the intelligent transportation vision system, according to the current problems of real-time, accuracy, robustness for unstructured road detection in complex environment, a new method is proposed for road detection. The means compresses data information of image through Gaussian pyramid down-sampling process and adopts bilateral filtering to suppress noise, then extracts edges of the filtered images based on modulus maximum of wavelet transform, uses threshold method to remove non-road edge points. A new K-means clustering algorithm is proposed which is based on slope and intercept, and it realizes road equation fitting. Experimental results show that this method can realize unstructured road detection more accurately in complicated road scene and improve real-time than traditional methods.
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Computer Engineering. 2014, 40(2): 162-165. https://doi.org/10.3969/j.issn.1000-3428.2014.02.035In the computer aided iris diagnosis, iris frill positioning is the foundation of the other iris anomaly feature detection. According this feature, this paper puts forward a detection method based on image gradient extreme. According to the vertical gray difference between the iris frill and its surrounding areas, it uses the improved gradient detection operator to get the image gradient value on the normalized image, extracts the maximum gradient value and gets the frill outline. Contour points are reduced and displayed in the original gray image. Experimental results show that the location accuracy of this method can reach 92.5%, and it has a good effect in the iris frill positioning problem.
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Computer Engineering. 2014, 40(2): 166-170. https://doi.org/10.3969/j.issn.1000-3428.2014.02.036The exist noises like junk mails in dynamic social network which affect the stability of the dynamic social network. The existed dynamic community detection algorithms cannot identify this kind of community structure correctly. Aiming at this problem, an algorithm called preFilter is proposed to solve the problems that the community structure cannot be identified correctly with the noise in the dynamic social network. It uses the relative entropy to filtering the noise in dynamic social network, then an improved incremental algorithm is proposed to identify community structure in the dynamic social network. Experimental results show that preFilter can reach a better performance than other dynamic algorithms, and get a stable NMI value and the modularity Q value which reaches about 0.8. This algorithm can avoid the influence of the noise effectively and performs effectively and accurately in identifying community structures in dynamic social networks.
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Computer Engineering. 2014, 40(2): 171-174. https://doi.org/10.3969/j.issn.1000-3428.2014.02.037Projection pursuit method is increasingly used in text categorization to solve the curse of dimensionality. Traditional projection pursuit method considers the projection index optimization as a single-objective problem rather than a multi-objective one, which will reduce the quality of the solution. To solve this problem, this paper proposes a projection pursuit mehod based on multi-objective optimization. Measures are taken like class difference and difference between the classes as two objectives of pursuit index, the projection pursuit method is extended to multi-dimensional projections, and a Chaotic Particle Swarm Optimization(CPSO) is suggested to find the optimal projection direction. Experiment on commonly used text datasets determines the optimal projection direction and dimensions, and then compares the results of different classification models. The results demonstrate that the proposed method can improve the text categorization performance effectively.
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Computer Engineering. 2014, 40(2): 175-179. https://doi.org/10.3969/j.issn.1000-3428.2014.02.038The traditional approach of semantic Web service discovery is centralized which leads to single point failure and performance bottleneck, quickly becomes impractical. Aiming at this problem, this paper presents a semantic Web service discovery algorithm in structured P2P networks. It partitions ontological concepts into different concept groups and defines group concepts to character service coarsely. Then it presents a service publishing/discovery algorithm based on group concepts generating vectors. The algorithm gets multi-keywords from service/query and realizes semantic Web service’s fuzzy match with appropriate redundancy in structured P2P networks. Experimental results show that the recall of this algorithm is increased from 15.2% to 37.1% compared with exact discovery algorithm.
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Computer Engineering. 2014, 40(2): 180-183,188. https://doi.org/10.3969/j.issn.1000-3428.2014.02.039An audio visual Dynamic Bayesian Network model with State Asynchrony(SA-DBN) transforming acoustic speech to photo realistic facial animation is proposed. Perceptual Linear Prediction(PLP) features from audio speech, as well as Active Appearance Model(AAM) features from face images of an audio visual speech database, are adopted to train the model parameters of the proposed SA-DBN. Based on the SADBN model, an input audio stream is given, the optimal AAM visual features are learned by the Maximum Likelihood Estimation(MLE) criterion, which are used to construct facial images for the animation. Subjective evaluation is presented to compare the proposed constrained state asynchrony DBN with a state synchronous audio visual DBN model. Experimental results show that with the SA-DBN model, high quality facial animations can be obtained with mouth movements matching the input speech.
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Computer Engineering. 2014, 40(2): 184-188. https://doi.org/10.3969/j.issn.1000-3428.2014.02.040Aiming at the problems of standard Invasive Weed Optimization(IWO) algorithm such as population diversity declining in the late evolution and easily trapping into local extremum, an improved algorithm, Multi Sub-population Invasive Weed Optimization algorithm based on K-means clustering(K-MSIWO), is proposed. In K-MSIWO, the weed population is divided into three sub-populations by using K-means clustering. The co-evolutionary relationship of individual and individual, sub-population and sub-population is established through intraspecific and interspecific competition to increase the diversity of the weed population. When the convergence velocity of algorithm begins falling, the random perturbation mutation strategy is adopted for the premature individual to help them out of local minimum. Experimental results on several benchmark functions show that the modified algorithm is applied to PID control parameter tuning of second-order and high-order system, the overshoots of the systems are reduced by 33.2% and 50% respectively compared with GA approaches, and K-MSIWO has better accuracy and consistency.
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Computer Engineering. 2014, 40(2): 189-192,198. https://doi.org/10.3969/j.issn.1000-3428.2014.02.041Aiming at the problems of traffic jams caused by highway traffic accident and improving highway operation safety, this paper proposes a subtraction clustering method combined with Adaptive Neural-fuzzy Inference System(ANFIS) applied in traffic incident duration prediction. Forecasting process is that extracting duration event related factors from I-880 database, using a parameter estimation method for significant analysis, choosing bigger factors as fuzzy system’s input samples, the subtractive clustering is introduced to confirm the fuzzy rule number to build the initial fuzzy inference system, the hybrid algorithm is used to train and optimize the fuzzy system and establish a final training fuzzy model. Simulation results show that the system for traffic incident duration prediction has higher detection rate and lower false positives, in general.
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Computer Engineering. 2014, 40(2): 193-198. https://doi.org/10.3969/j.issn.1000-3428.2014.02.042Received Signal Strength Indication(RSSI) of the Zigbee Wireless Sensor Network(WSN) can be used for providing location service. Using RSSI establishing fingerprint database to design positioning algorithm can get good positioning result. But fingerprint database collection and establishment accuracy directly affect the positioning accuracy. The general method to establish the fingerprint database has larger error, and after researching for the process of Zigbee network fingerprint database collection and establishment, the fingerprint database collection, establishment and optimization method is proposed. In the positioning area, all the collected fingerprint database source data from every sampling point are filtered, and high precision fingerprint database is established. Using the defined region adjacent algorithm, defined region weighted adjacent algorithm and defined region Bayesian algorithm are proposed for this positioning system calculates user’s location, respectively. Experimental result shows that the average error using the optimized fingerprint database is limited within 1.5 m in short range positioning system.
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Computer Engineering. 2014, 40(2): 199-202,207. https://doi.org/10.3969/j.issn.1000-3428.2014.02.043Epilepsy is a brain disease. As the disease is sudden and repeated, which poses a great threat to safety of patients, effective prediction to seizure is of important significance to prevention and treatment. In this paper, dataset comes from University of Freiburg, Germany Prediction Center. Independent Component Analysis(ICA) is used to remove redundancy. Auto regression model is used to extract multi-channel features of changing trend along with time series. Prediction is transferred to classification by Support Vector Machine(SVM) and filter. All the results can be finally got by Monte Carlo statistical methods. Results show that the models can predict seizures in advance 30 min~70 min with false positive rate nearly zero, which may provide good theoretical basic for developing clinical epilepsy warning system.
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Computer Engineering. 2014, 40(2): 203-207. https://doi.org/10.3969/j.issn.1000-3428.2014.02.044A forward vehicle detection method based on multi-feature fusion is proposed in order to improve the accuracy of vehicle detection. The shadow and edge features of vehicle are segmented accurately by using histogram analysis method and adaptive dual-threshold method respectively. The initial candidates are generated by combining edge and shadow features and these initial candidates are further verified by using an integrated feature based on the fusion of symmetry, texture and shape matching degree features. A threshold is used to remove the non-vehicle initial candidates. Experimental results show that this method can adapt to different light conditions robustly with a detection rate over 92%. The proposed method is better than traditional methods based on learning with a higher detection rate and lower error rate.
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Computer Engineering. 2014, 40(2): 208-211,218. https://doi.org/10.3969/j.issn.1000-3428.2014.02.045A kind of parallel architecture based on CPU and GPU is proposed to solve the low speed in high-resolution of multi-channel video stitching system, and this design is implemented on the physical platform successfully. The image pyramid module is deleted and a partial overlap ROI is improved from the traditional Oriented Features from Accelerated Segment Test(FAST) and Rotated Brief(ORB) algorithm. The image data after registration on the CPU side are then fused on the GPU side parallelly. Since the GPU and the CPU device call the execution asynchronously, the ORB image registration of the current frame on the CPU side and the image fusion of the previous frame on GPU side are executed parallelly. At last, the image fusion data which is computed by Compute Unified Device Architecture(CUDA) can be shared with the render device of GPU. It is this optimization that enhances the speed of the render. The result shows that the frame of this panorama video-stitching system can achieve 17 f/s, which meets the real-time demand in large scene.
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Computer Engineering. 2014, 40(2): 212-218. https://doi.org/10.3969/j.issn.1000-3428.2014.02.046In order to improve the distribution and convergence of multi-objective evolutionary algorithm, a kind of Hamming distance- based differences multi-objective evolutionary algorithm is proposed. Hamming grades are defined on the basis of the non-dominated frontier, choosing Hamming distance to operate the individuals. Hamming difference and Pareto evaluation methods are combined to update and maintain the optimal solution of the external memory, using structural similarity to build niche space and guide the algorithm towards Pareto optimal frontier. The test of 6 typical functions shows that, the proposed algorithm has better convergence while maintaining a good uniform distribution than other compared algorithms.
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Computer Engineering. 2014, 40(2): 219-223. https://doi.org/10.3969/j.issn.1000-3428.2014.02.047Aiming at the problem of the damage and distortion of image content existing in the traditional image resizing, an effective image scaling algorithm combining seam carving with scaling is proposed. An image is first resized using seam carving, then the Scale Invariant Feature Transform(SIFT) features are extracted from the original image and the resized one respectively, and the SIFT features between two images are matched and calculated to obtain their similarity distance. When the similarity distance between the original and the resized image reaches a certain threshold, namely, before the salient object and content are damaged obviously, seam carving is stopped and scaling is adopted for the residual task. Experimental results show that this algorithm is able to avoid the damage and distortion of image content and preserve both the local structure and the global visual effect of the image graciously.
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Computer Engineering. 2014, 40(2): 224-228. https://doi.org/10.3969/j.issn.1000-3428.2014.02.048The breast image cannot match by using the method of rigid matching because of its non-rigid characteristics. To solve this problem, this paper proposes a mass matching method based on layering algorithm. Use the method of Otsu threshold segmentation to intercept the pectoral region and use the least-squares method to fit the chest wall line, and establish local coordinate system to identify the matching bar area by finding out the position of nipple and central axis. It extracts the suspected lesion area in the bar areas by using layering algorithm, and by measuring the similarity based on the weighted mutual information to realize the mass matching. It analyzes the feasibility of the stratified mass matching method and does experiments. This paper selects 100 pairs of images to carry out the experiments of mass match. The experimental results show that the layering algorithm for mass matching is more effective than the non-layered algorithm, and the matching precision reaches 86%.
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Computer Engineering. 2014, 40(2): 229-232. https://doi.org/10.3969/j.issn.1000-3428.2014.02.049There are some problems in the typical gradient projection algorithms in the application of Compressed Sensing(CS), such as the large amount of calculation, the low efficiency of convergence process and excessive dependence on the sparsity of the data matrix. In order to deal with these problems, an efficient recovery algorithm is proposed. This algorithm is based on CS which combines the Quasi-Newton method and the gradient projection method. So it can make full use of the estimating and correcting procedure and the global superlinear convergence of the Quasi-Newton method. By correcting the objective function with the Quasi-Newton method, a more accurate searching direction and fewer iteration can be got. It makes the algorithm perform efficiently with a high convergent reconstruction based on compressed sensing. Experimental results prove that this algorithm shows a good reconstruction and anti-noise performance. Compared with the traditional gradient projection recovery method, the proposed method drops the error rate to make a more stable and convergent reconstruction with fewer iteration.
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Computer Engineering. 2014, 40(2): 233-236. https://doi.org/10.3969/j.issn.1000-3428.2014.02.050Discrete Cosine Transform(DCT) and wavelet transform are used for sparse representation, but DCT can’t analyse well in domain of time and frequency. The directional selectivity of wavelet transform is poor and can’t reconstruct edge information well enough. Against the optimization of sparse representation, Curvelet transform has characters of multi-scale, singularity and more sparsity. This paper proposes a compressed sensing reconstruction algorithm based on Curvelet transform, which uses Curvelet transform for sparse representation and thresholding method in wavelet domain to solve the noise problem of signal reconstruction. Results demonstrate that the algorithm gets 1.86 dB higher Peak Signal to Noise Ratio(PSNR) and 1.15 dB higher PSNR compared with traditional wavelet transform and Contourlet transform. As Curvelet transform is applied to compressed sensing, optimal result of edge and smooth part of image are got, also the reconstructed quality of details is increased.
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Computer Engineering. 2014, 40(2): 237-239,245. https://doi.org/10.3969/j.issn.1000-3428.2014.02.051Imaging in the atmosphere is often degraded by scattering due to atmospheric particles such as haze, fog, and mist, which brings great inconvenience to the imaging of computer vision system. This paper presents a method based on the depth of field of the single image defogging algorithm quickly to solve this problem. Through dark channel prior on image processing, it gets image transmission chart, thereby simplifies the atmospheric scattering model. It uses depth of field information estimation of atmospheric scattering model to get the depth relationships of scene edge. Through nearly horizontal death ratio improving transmission chart, it uses bilateral filtering for image edge processing. Starting from three color channels reduces the effect of wavelength on estimating depth of field. Experimental results show that this algorithm can effectively recover scene edge contrast details, and effectively improves image clarity, resulting in a great improvement in image visibility.
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Computer Engineering. 2014, 40(2): 240-245. https://doi.org/10.3969/j.issn.1000-3428.2014.02.052In field conditions, the scattering effect of atmospheric particles leads to serious image degradation and seriously influences the visual effect and application value, which makes it absolutely necessary to defog the image, so as to improve the definition and fidelity. Based on the principle of dark channel priority, this paper uses the region growth algorithm to accurately estimate the depth information of the fog image, and uses the fog image physical model to defog the image and compensate the luminance of the image. Experimental result shows that the algorithm efficiently improves image quality and greatly reduces the time needed in the image fog removal process compared.
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Computer Engineering. 2014, 40(2): 246-249,255. https://doi.org/10.3969/j.issn.1000-3428.2014.02.053Aiming at the problem of human instep 3D modeling, a new scheme that uses line-structured light scanning to reconstruct 3D model and measure parameters is presented. Line structure light photos are taken by 2 high resolution CMOS cameras from different angles. To get the point cloud data of instep, the scanning images are thinned by gray-gravity method and image coordinates is transformed to world coordinates. The least squares curve fitting algorithm is used to fix the blind data in human heel zone. And the 3D Delaunay triangulation algorithm is used to restructure the curved face of instep and get a complete human instep 3D model. Experimental result shows that the running of the scheme is stable, the absolute error of the main parameters of foot is less than 4 mm, and it has high accuracy.
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Computer Engineering. 2014, 40(2): 250-255. https://doi.org/10.3969/j.issn.1000-3428.2014.02.054Aiming at the high-complexity and low-efficiency of constructing 3D geologic sections, an 3D geological section generating algorithm based on octree is proposed. It is an improvement of the traditional geologic sections generating method, which reduces the time complexity to O(log8(n/M)) in the search process. Besides, it adds boundary constraints for preprocessing, guarantees the correctness and the order of the boundaries, and becomes more robust. The algorithm creates spatial index for triangles on complex 3D geologic body mesh models and searches triangles on geologic sections plane based on octree, then computes the intersection points and traces boundaries of geologic sections. The algorithm constructs 3D geologic sections, and uses gallery guard algorithm to triangulate the traced boundaries. Experimental results prove that this method not only has advantages of high-efficiency and robustness, but also reduces the time complexity from O(n2) to O(nlbn) compared with traditional algorithm.
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Computer Engineering. 2014, 40(2): 256-258,262. https://doi.org/10.3969/j.issn.1000-3428.2014.02.055Brain tumor segmentation plays an import role in computer-aided diagnosis. In order to improve the precision of brain tumor segmentation, this paper proposes a brain tumor segmentation method using geodesic combined with Gaussian Mixed Model(GMM). A discrete weighted graph which the edge-weights present the arrival time between the neighbors is constructed, the penalization that the pixel belongs to the target object is computed. The cost energy function consists of the region and edge terms. The geodesic distance is computed by using the shortest path fast algorithm. The brain tumor is detected by the minimizing the energy function according to the geodesic distance. The algorithm is tested on ten sets of MR image datasets and the overlap values between the segmentation result of the proposed algorithm and the ground truth is 0.60~0.85. Experimental results illustrate that the algorithm can reduce the local minimization and it has high efficiency in heterogeneous regions.
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Computer Engineering. 2014, 40(2): 259-262. https://doi.org/10.3969/j.issn.1000-3428.2014.02.056Color is an important visual feature. Color Correlogram(CC) algorithm is commonly used in the color based image retrieval as a feature descriptor, but most of the existing methods based on CC have problems of high computational complexity and low retrieval accuracy. Aiming at this problem, this paper proposes an image retrieval algorithm based on color autocorrelogram and mutual information. It presents a novel color feature descriptor, namely Color Mutual Information(CMI). The new color feature vector which describes the global and spatial distribution relation among different colors is obtained by calculating the average mutual information between one color and all the colors around it in the CC feature matrix, thus reducing the computational complexity. Inter-feature normalization is applied in the combination of CMI and color autocorrelogram to enhance the retrieval accuracy. Experimental result shows that this integrated method can reduce the computational complexity, improves real-time response speed and retrieval accuracy.
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Computer Engineering. 2014, 40(2): 263-266,270. https://doi.org/10.3969/j.issn.1000-3428.2014.02.057Aiming at the issue that the traditional Description Logic(DL) ALCQ based on classical collection cannot describe complex, fuzzy and dynamic knowledge, this paper introduces extension set to be the set theory foundation of the description logic ALCQ and proposes a new description logic ALCQDES with qualifying number. By defining the grammatical form of ALCQDES concept, relationship and TBox axioms, as well as ABox assertions and giving the semantic interpretation of ≥kR.C and ≤kR.C on a basis of semantic interpretation method of extension set and the traditional description logic, ≥kR.C and ≤kR.C expansion rules of the consistency checking algorithm TableauDES* is presented with the research on basic reasoning problems of ALCQDES. The extension logic ALCQDES shows better descriptive ability to knowledge than the traditional description logic ALCQ and fuzzy extension description logic FALCQ.
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Computer Engineering. 2014, 40(2): 267-270. https://doi.org/10.3969/j.issn.1000-3428.2014.02.058This paper introduces the widely adopted J-Link emulator and processor based on Loongson core in embedded system. It describes the realization of porting J-Link protocol to Loongson platform and the key steps of porting are presented. The key steps are the J-Link initialization, the organization of EJTAG control data, J-Link protocol encapsulation, data alignment and using of USB protocols. Porting is implemented on Loongson platform successfully and experimental result shows that when on line programming Flash with EJTAG in ported J-Link emulator, the programming speed and system stability are significantly enhanced.
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Computer Engineering. 2014, 40(2): 271-274,279. https://doi.org/10.3969/j.issn.1000-3428.2014.02.059UCGUI is a graphical user interface library which is widely used in real-time embedded system. As it does not support Chinese character set, a method to support Chinese character by adding GB2312 Chinese character coding is proposed. This paper designs and implements a font drive program by which font data is separated from UCGUI library code, including drive for extended font, font data access interface & method. Font drive is tested on the UCGUI simulators and is completely compatible with the UCGUI library. This makes up for technical blank of Chinese display in low-cost embedded system with UCGUI library.
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Computer Engineering. 2014, 40(2): 275-279. https://doi.org/10.3969/j.issn.1000-3428.2014.02.060In this paper, a method on modeling user’s interests based on short text of micro-blog is presented. In order to overcome the lack of information in short text, on the base of analyzing the structure and content of micro-blog short text, this paper proposes an approach on micro-blog short text reconstruction, and namely, according to the other related and the three kinds of special symbols of the text, extends the content, thereby extending the characteristic information of original micro-blog. It takes advantage of HowNet2000 concept dictionary to map the feature set of reconstruction text to a set of concepts. It clusters the set of concepts to divide user’s interests, and meanwhile, a representation mechanism of user interest model is presented. Experimental results show that the short text reconstruction and concept mapping can improve the effect of clustering. Compared with the modeling based on collaborative filtering, F-Measure value is increased by 29.1%. This means the proposed micro-blog user’s interest modeling has a better performance.
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Computer Engineering. 2014, 40(2): 280-283,288. https://doi.org/10.3969/j.issn.1000-3428.2014.02.061A new method based on geometrical principle and stepping search, waypoint searching method, is proposed to improve the effectiveness and applicability with menace for route planning of military aircrafts. The models of flight-forbidden area, radars, air defense weapons and the terrain obstacles such as a high mountain are established, and the cost function during the route planning is deduced. The process and principle of how to obtain waypoints in planning space and how to select the waypoints which are acquired to make the route by waypoint searching method is introduced, and the optimal route is obtained with the cost function. The simulation based on waypoint searching method is implemented, and the results show that it is simple, has better convergence, and is not sensitive to menace. Thus, this method has a great value in the practical applications.
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Computer Engineering. 2014, 40(2): 284-288. https://doi.org/10.3969/j.issn.1000-3428.2014.02.062In order to meet the demands of the network management and control of video service in the tri-networks integration background, the advantages and disadvantages of using KAD protocol in high concurrent and real-time environment are analyzed and a scheduling management strategy based on loaning video service nodes between resource pools is proposed to minimize redundancy information and delay time of system. Divide the video service nodes into a number of resource pools based on the connectivity between video service node and different networks and each pool is organized by KAD protocol. Adopt a method of loaning available video service nodes from other pools to avoid overload or denial of service when a large number of video requests are predicted. Experimental result shows that the Markov chain prediction method can warn the overload state effectively and false negative rate achieves zero. The resource of video service nodes can be balanced based on the mechanism.
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Computer Engineering. 2014, 40(2): 289-293,299. https://doi.org/10.3969/j.issn.1000-3428.2014.02.063The communication connection among subsystems of the integrated embedded systems is achieved by an external bus. In order to solve interface test problems of the integrated embedded system, integrated embedded systems are simulated by embedded systems virtual machines which create external bus simulation modules. And the communication among virtual machines is achieved by configuring connections of these modules. This technology presents an external bus simulation structure based on Ethernet communication, and takes Controllers Area Network(CAN) bus simulation as an example. It establishes shared memory for bus device interface reading and writing data and achieves the data exchange between simulation node modules via configurations of internal bus on QEMU which is a system virtual machine, registrations of external bus devices, organizations of bus protocol packets and sending and receiving packets through the network, so as to achieve the data communication capabilities of simulation bus.
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Computer Engineering. 2014, 40(2): 294-299. https://doi.org/10.3969/j.issn.1000-3428.2014.02.064High precision and high performance floating-point unit is an important research object of high performance microprocessor design. According to the characteristic of Quadruple Precision(QP) floating-point data format and research on double precision floating-point multiplier accumulator algorithms, a high performance Quadruple Precision Floating-point Multiplier Accumulator(QPFMA) is designed and realized, which supports multiple floating-point arithmetic with a 7 cycles pipeline. By adopting dual path adder and improving on algorithm architecture, optimizing leading-zero-anticipation and normalization shifter logic, the latency and hardware area is decreased. And by making use of parameterized design and verification methodology, the correction of the QPFMA is verified efficiently. Based on 65 nm technology, as the synthesis results show that the QPFMA can work at 1.2 GHz, with the latency decreased by 3 cycles and the frequency increased by about 11.63% compared with current QPFMA design.
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Computer Engineering. 2014, 40(2): 300-302,307. https://doi.org/10.3969/j.issn.1000-3428.2014.02.065Flash Translation Layer(FTL) is always needed when NAND Flash is used in a memory device. Page level translation is the most popular, but needs a large RAM to store mapping table. This pager employs a superblock based hybrid mapping, and realizes a basic FTL on the Solid State Disk(SSD) development board. The test result shows that the hybrid FTL has good sequential read and write performance, and only needs 128 KB SRAM, which is far less than page level mapping. It also does not need to store mapping table. The program runs successfully in solid state disk development board, to achieve the basic functions of solid state disk read and write. Test results show that, the hybrid mapping FTL scheme has better sequential read and write performance.
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Computer Engineering. 2014, 40(2): 303-307. https://doi.org/10.3969/j.issn.1000-3428.2014.02.066In order to enhance the ability of Radio Frequency Identification(RFID) systems to identify a large number of tags, an adaptive multi-way tree anti-collision algorithm based on prior knowledge is proposed. The new algorithm can estimate the number of tags and adjust the number of search fork in different branches and depths dynamically according to the regularity and random distribution of tags. According to the prior knowledge, the new algorithm can enhance the search efficiency. Theoretical analysis and simulation results show that the new algorithm overcomes the shortcomings of the traditional multi-way tree anti-collision algorithm, it can effectively improve throughput of RFID systems especially when the number of tags is large.
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Computer Engineering. 2014, 40(2): 308-313. https://doi.org/10.3969/j.issn.1000-3428.2014.02.067In the multi-industry information products processing system of the remote sensing field, the principle of distributed computing is used to process the remote sensing data, and it is necessary to monitor and manage the processing nodes. To address this problem, a network hardware monitoring system is proposed, which is consisted of three independent parts called monitoring client, monitoring server and monitoring agents. In order to monitor each data processing server in the system, the method combines the Windows Management Instrumentation(WMI) technology and Log4net technology is adopted, and the means of communication is improved and heartbeat detection is also added. Through the implementation of the network hardware monitoring system, the results prove that the program can obtain the monitoring information of each processing node in real-time effectively, an intuitive graphical interface is used to show the monitoring results to managers, and the improving communication means ensuring each component can initiatively discover abnormity.
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Computer Engineering. 2014, 40(2): 314-316. https://doi.org/10.3969/j.issn.1000-3428.2014.02.068For the problem that there are lots of works to do including instantiating and placing and routing parameterized cells to generate huge amount of test chips in the layout editor manually in the process development verification flow, an automatic flow of test chip generation for process development verification is raised. A software interface that generates skill script is used to get information about process development and communicate with and send command to them. The method can help instantiate and place and route parameterized cells as well as floor planning automatically. The software interface is used to develop test chips for a 40 nm semiconductor technology process design kits. The average time to generate a test chip by this software interface is 5.2 s. The result approves that the method is efficient and can decrease the time to verify process design kits.
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Computer Engineering. 2014, 40(2): 317-320. https://doi.org/10.3969/j.issn.1000-3428.2014.02.069In practice of High Frequency(HF) Radio Frequency Identification(RFID) implementation, it is very hard to read multiple tags which are closely stacked because of insufficient energy scavenging caused by resonance frequency shifting. In order to solve this stacked tags problem, theoretical analysis of the stacked-multi-tags model is conducted and a novel variable frequency carrier method is proposed to match the shifted stacked tags’ resonance frequency. Experimental results show significant performance improvement compared with standard HF RFID reader in the condition of same radio frequency power and reading distance.
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