Synchronization is one of the key technologies to maintaining the consistency of replicated mobile database systems. A new synchronization scheme, double-timestamp transaction-level synchronization (DTSTLS) model, is ...
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Synchronization is one of the key technologies to maintaining the consistency of replicated mobile database systems. A new synchronization scheme, double-timestamp transaction-level synchronization (DTSTLS) model, is put forward. DTSTLS model utilizes a three-tire architecture. Therefore existing database products can be used as its database server. As an asynchronous group replication method, DTSTLD model allows mobile users to access local replicas of the database and to locally submit mobile transactions when the system is disconnected. The locally committed transactions are sent to the synchronization server for conflict reconciliation and synchronization when the system is reconnected. Mobile transactions that have executed conflicting operations will be aborted, and only those mobile transactions that do not violate the consistency of the database system can be globally committed. In this way, the consistency of the database system is ensured. Detailed simulation experiment results show that the proposed methodology not only ensures the serializability and consistency of the mobile database system, but also reduces storage consumption and communication cost.
In this paper, we propose a coarse estimation scheme of carrier frequency offset ID orthogonal frequency division multiplexing (OFDM) systems. The proposed method uses the correlation which is put between the subcarri...
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In this paper, we propose a coarse estimation scheme of carrier frequency offset ID orthogonal frequency division multiplexing (OFDM) systems. The proposed method uses the correlation which is put between the subcarriers of the training symbols to estimate the integer part of the relative frequency offset. The algorithm can estimate relatively wide range of carrier frequency offset in spite of its much lower comp.tational comp.exity comp.red to the conventional cross-correlation methods. Simulation results show that the missing rate of the coarse estimator is sufficiently low and the variance of the final estimates approaches the Cramer-Rao lower bound at resonable range of signal- to-noise ratios (SNR's).
A novel approach to continuous, whole-sentence Chinese Sign Language (CSL) recognition based on large vocabulary is presented. In order to improve the recognition speed and accuracy, some useful new ideas are proposed...
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A novel approach to continuous, whole-sentence Chinese Sign Language (CSL) recognition based on large vocabulary is presented. In order to improve the recognition speed and accuracy, some useful new ideas are proposed, including modifying the transferring probability, states tying, fast matching and using the estimating parameter of transferring between signs in search algorithm. The aim of state tying is to reduce comp.tation load in decoding process. Fast matching is used to decide which signs is the potential one. Adding a parameter can weaken the effect of the extra movement between two signs. Using these techniques, a real-time system designed for recognizing continuous Chinese Sign Language sentences with a large vocabulary based on two CyberGloves and a tracker is built. Experiments are carried out on 5100 signs included in Chinese Sign Language Dictionary. 1000 continuous sentences are tested. These sentences are made randomly based on the vocabulary. The results show that the techniques proposed in this paper are efficient on either recognition speed or recognition rate. The sentences can be recognized in real-time.
This paper discusses an applied high resolution airborne SAR signal processing system, its processing flow and its architecture. It also discusses the possible applications to other intense signal processing areas. Si...
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This paper discusses an applied high resolution airborne SAR signal processing system, its processing flow and its architecture. It also discusses the possible applications to other intense signal processing areas. Since the universal bus, microprocessors, DSP chips and Linux have been applied, both hardware and software modules in this system have been standardized. This will accelerate the further development.
This paper introduces an algorithm used in estimation of the phase error of chirp signal. Firstly, the algorithm applies Range Coll Migration Correction (MCRC) to SAR signals with chirp scaling method, and processes o...
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This paper introduces an algorithm used in estimation of the phase error of chirp signal. Firstly, the algorithm applies Range Coll Migration Correction (MCRC) to SAR signals with chirp scaling method, and processes on azimuth comp.ession only. Then the phase error of the radar chirp signal is estimated by applying the auto-focus method, for example, Map Dcift(MD) OT Phase Gradient Algorithm (PGA) to the azimuth processing of signals. Further correction on estimated phase error is applied to discussion of the factors that influent the phase error estimation. The algorithm is proved by comp.ter simulation.
This paper proposes a new B-spline active contour model. The affine template is derived and then coupled with the active contour through the potential energy in the Lagrangian dynamics equation. Accordingly, the propo...
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This paper proposes a new B-spline active contour model. The affine template is derived and then coupled with the active contour through the potential energy in the Lagrangian dynamics equation. Accordingly, the proposed model for visual tracking is affine invariant. Moreover, the paper discusses the stability of the control system in the sense of Lyapunov. To track objects in comp.ex background effectively, the paper also presents a novel feature detection technique, which integrates much image information and as a result is robust for tracking in cluttered images. The experiments with real image sequences show the effectiveness of the new model.
An approach modifying the binary code of that program by ELF-Rewriter directly and distributing the comp.tation loads among the whole cluster system without touching the source code is presented. The ELF-Rewriter inje...
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An approach modifying the binary code of that program by ELF-Rewriter directly and distributing the comp.tation loads among the whole cluster system without touching the source code is presented. The ELF-Rewriter injects a stub code segment into the host program, responsible for the communication between host program and Task Dispatcher, and host program and Communication Server. When original shared library calls in the host program are captured, ELF-Rewriter just redirects them to the newly injected stub code segment. Then The Communication Client and the Task Executing Agent on each node are designed to transfer and execute comp.tation loads. When running on cluster, there is one Master node for the host program, and the others are Worker nodes. The Master node no longer executes the CPU intensive library calls in fact, but only communicates with Worker nodes. A testing framework of this comp.ting model also is developed, and a Master-Worker (Task-Farming) comp.tation and communication model with corresponding scheduling policy is proposed and discussed. Finally, a multi-threaded matrix multiply program based on BLAS v3 library is implemented, and being ported to cluster environment so as to verify the feasibility and efficiency of the model. By the ELF executable PLT redirection, it is not needed that changing the source code to manually distribute the loads. It is automatically distributed to all nodes. The concurrency and synchronization of the host multi-threaded program are utilized, no extra synchronization is needed. By this mean a user-transparent cluster range parallel mechanism is provided.
QUICKFIT, a quick algorithm is developed by analyzing the properties of the preparatory algorithm of Bound Fit and integrating Bound Fit with MULTIFIT for scheduling independent tasks on identical parallel processors ...
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QUICKFIT, a quick algorithm is developed by analyzing the properties of the preparatory algorithm of Bound Fit and integrating Bound Fit with MULTIFIT for scheduling independent tasks on identical parallel processors to minimize the make span. For the same tasks and machines, QUICKFIT needs a fewer iterations than MULTIFIT and Bound Fit to obtain the same make span. Experimental results show that the greater the task-to-machine ratio is, the better the performance of QUICKFIT is than MULTFIT and Bound Fit, and the make span of QUICKFIT is the least among those of LPT, MULTIFIT and Bound Fit in most of cases, and QUICKFIT is suitable for the large scale identical scheduling.
The nonsimultaneous multiprocessor scheduling problem (NMSP) is a generalization of the classical simultaneous multiprocessor scheduling problem (SMSP), where all jobs and machines are available at time zero. NMSP con...
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The nonsimultaneous multiprocessor scheduling problem (NMSP) is a generalization of the classical simultaneous multiprocessor scheduling problem (SMSP), where all jobs and machines are available at time zero. NMSP concerns the nonpreemptive assignment of nindependent jobs on m parallel machines in order to minimize the makespan, in which all jobs are available at time zero but some machines may not available at time zero. MLPT and MULTIFIT are two typical algorithms for NMSP. In this paper, both MLPT and MULTIFIT are modified. MMLPT (Modified MLPT) needs less running time than MLPT and MMULTIFIT (Modified MULTIFIT) needs fewer iterations than MULTIFIT. CMM is presented which combines MMLPT with MMULTIFIT in such a way that the initial upper bound of MMULTIFIT starts with the makespan of MMLPT. The comp.exities and scheduling outcomes of MLPT, MULTIFIT and CMM are analyzed and comp.red theoretically. Experimental results show that the average iterations of MMULTIFIT is fewer than that of MULTIFIT, the average number of iterations of CMM is rather fewer even than that of MMULTIFIT and the performance of CMM is not worse than the better of MMULTIFIT and MMLPT. CMM can be used to such problems as the work floor jobs scheduling in enterprises, the processors scheduling in comp.ter systems, etc.
Virtual enterprise modeling (VEM) is regarded as the basic support for studies on virtual enterprises. A UML-based VEM(VEM-UML) method, is put forward. This modeling method leads the key modeling concepts of VEM into ...
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Virtual enterprise modeling (VEM) is regarded as the basic support for studies on virtual enterprises. A UML-based VEM(VEM-UML) method, is put forward. This modeling method leads the key modeling concepts of VEM into UML by extending the new metaclasses and stereotypes. The extension together with the inherent properties of UML makes the VEM-UML an efficient virtual enterprise modeling language. A virtual enterprise for designing and manufacturing helicopters is modeled to prove the effectiveness of VEM-UML in modeling virtual enterprises. comp.red with the traditional enterprise modeling methods, the advantages of the VEM-UML method are highlighted in modeling virtual enterprises. Finally, the mapping mechanism from the VEM modeling concepts to the UML modeling elements is presented to provide VEM an abstract syntax and semantics.
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