The classification and detection of single timing faults in timed FSMs are introduced. A graph augmentation method is used to formulate the detection models for timing faults. It is shown that, by using our graph augm...
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The classification and detection of single timing faults in timed FSMs are introduced. A graph augmentation method is used to formulate the detection models for timing faults. It is shown that, by using our graph augmentation models, a faulty IUT ends up in a different state than the intended one, hence, enabling the detection of these single timing faults
A well-developed pose estimation scenario suitable for low altitude unmanned aerial vehicle (UAV) is proposed. By employing dual CCD cameras onboard, the instant pose of UAV can be determined without any use of expens...
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A well-developed pose estimation scenario suitable for low altitude unmanned aerial vehicle (UAV) is proposed. By employing dual CCD cameras onboard, the instant pose of UAV can be determined without any use of expensive sensor like gyro. The unscented Kalman filter (UKF) is hereafter introduced to resolve the highly nonlinear system dynamics as well as the measurement process of the pose estimation system. The only measurements recorded are those snapshots of ground targets/landmarks taken by two CCD cameras. The proposed scenario can also detect large angle rotation of UAV. Simulation is conducted via a simple case, both UAV and ground targets are stationary, to show the feasibility and applicability of the proposed scheme. Actual GPS measurement data of ground targets coordinates was recorded for UKF processing. A highlight phenomenon, implied by simulation, reveals that a sudden transition of estimation errors arises at the epoch when the UAV is experiencing a large angle maneuvering up to 180/spl deg/ per second.
An arbitrary pattern exposure system has been developed by employing a liquid crystal display (LCD) with 1600 × 1200 pixels for the formation of projection images in place of a conventional reticle. The minimum p...
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The U.S. Navy's Automated Digital Network System (ADNS) serves as the primary means of ship-to-shore and ship-to-ship WAN connectivity. As such, ADNS is a key element of current and future naval network architectu...
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ISBN:
(纸本)1563477122
The U.S. Navy's Automated Digital Network System (ADNS) serves as the primary means of ship-to-shore and ship-to-ship WAN connectivity. As such, ADNS is a key element of current and future naval network architectures. A major limitation of current ADNS networks is their inability to provide prioritized service for mission-critical traffic and end-to-end quality of service over high-delay, low-bandwidth satellite links. Accordingly, an upgrade strategy has been developed to provision ADNS with Differentiated Services (DiffServ) and priority queuing. Weighted Random Early Detection (WRED) is a key congestion avoidance mechanism within the ADNS DiffServ model. However, the tuning of different WRED parameters is essential in optimizing performance for high-priority traffic and in achieving predictable throughput, delay, and packet loss guarantees. This paper describes the results of ADNS QoS testing of the proposed WRED configuration to ascertain its performance relative to best-effort networks. An alternate WRED configuration is proposed to further enhance network performance. Test results suggest that use of the alternate WRED settings will improve throughput and maintain low packet loss rates for high-priority traffic.
We have developed a method of catalyst preparation for carbon nanotube (CNT) growth that uses solid-state diffusion to precipitate Co particles in a Cu matrix and control the size and size distribution of catalyst par...
We have developed a method of catalyst preparation for carbon nanotube (CNT) growth that uses solid-state diffusion to precipitate Co particles in a Cu matrix and control the size and size distribution of catalyst particles. Copper is an excellent electrical and thermal conductor, and has a small or negligible solubility for Co. Cu–Co alloys of approximately 5 atm% Co were formed in bulk by splat quenching the liquid alloy and on Si substrates by e-beam evaporation of the alloy, sputtering of the alloy, and sputter deposition of thin films of pure Cu and Co. The Co easily precipitates from dilute solutions of Cu–Co with heat treatment. These alloys and films were used to generate uniform distributions of Co precipitates, and CNTs were successfully grown by plasma enhanced chemical vapor deposition (PE-CVD) and thermal CVD on the materials. These alloys can be patterned by photolithography and sputtering in order to grow CNTs in defined locations. Therefore, the technique is amenable to very large scale silicon integration for field emission applications. The results of this work and data from field emission studies are presented herein.
the wireless ad hoc network is attracting more and more research attentions because of its infrastructureless character. A number of routing algorithms are proposed for multi-hop ad hoc networks. There is a debate in ...
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ISBN:
(纸本)0780382196
the wireless ad hoc network is attracting more and more research attentions because of its infrastructureless character. A number of routing algorithms are proposed for multi-hop ad hoc networks. There is a debate in the literature that a period of route information initialization, which is defined as the initial determination of necessary route information before the transmission of real data packets, should help to improve the performance of pure on-demand routing algorithms for ad hoc networks. In this paper, we study how route information initialization affects the performance of two on-demand routing algorithms for ad hoc networks, DSR and AODV. We examined the effects of various duration of initialization time upon performance, and the effects of fixed-duration of initialization with various mobility patterns upon performance. Through simulations as well as analysis, we find that under a certain network condition, there is an optimal value of initialization duration to get the best end-to-end delay without degradation of packet delivery rate and increase of the message overhead for DSR routing protocol, while the best value does not exist for AODV. In addition, we also find that the route information initialization does help to improve DSR's end-to-end delay almost without degradation of its delivery rate for low mobility networks, however, it does not bring benefits to AODV under most circumstances.
A novel computational scheme has been used to predict the electric potentials generated by arbitrary temperature gradients in semiconductor materials. Written in object-oriented code, the Discrete State Simulation (DS...
A novel computational scheme has been used to predict the electric potentials generated by arbitrary temperature gradients in semiconductor materials. Written in object-oriented code, the Discrete State Simulation (DSS) is a coupled cellular automata simulator that builds upon the objects and rules of quantum mechanics. The DSS represents global non-equilibrium processes as patterns that emerge through an ensemble of scattering events that are localized at vibronic nodes. By tracking the energy-momentum-position coordinates of the individual particles that define the vibronic state at a node, the DSS undercuts equilibrium concepts such as temperature. Consequently, the DSS can represent physical systems that are described by more than one temperature or that contain physical features that defy definitions of temperature. Using modified bootstrap sampling algorithms, the DSS depicted (1) shifts in distribution functions induced by external fields and temperature gradients, (2) field-dependent transitions from linear mobility to non-linear mobility, (3) saturation velocities, (4) non-exponential decay functions generated by multiple phonon scattering modes, and (5) charge separations and electric potentials generated by temperature gradients. Ensemble averages were sensitive to the structure of dispersion relations, to the energy of the system, and to quantum coupling strengths. Seebeck coefficients were sensitive to the features of the electronic and the vibrational band structures, and their associated coupling coefficients.
Information technology is providing manufacturers with additional flexibility with regard to their supply chain network choices. Our research studies supply chain network organization structures categorized by the org...
Information technology is providing manufacturers with additional flexibility with regard to their supply chain network choices. Our research studies supply chain network organization structures categorized by the organic and mechanistic management control structures. The structural impacts on cost and fill rate performance are studied in two-echelon and two-supply-chain network organization models under different market coordination conditions using system dynamic simulations. Our results show significant effects of demand and network structural factors, and their interactions, on these measures. As demand becomes dynamic, the cooperative interaction model, where supply chains cooperate to satisfy customer demand, is found to have better system performance than the competitive supply chain model. The analysis also suggests that increasing the responsiveness at the downstream plant is particularly important to the overall system performance improvement.
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