2,260 research outputs found

    The MacWilliams identity for quantum convolutional codes

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    In this paper, we propose a definition of the dual code of a quantum convolutional code, with or without entanglement assistance. We then derive a MacWilliams identity for quantum convolutional codes. Along the way, we obtain a direct proof of the MacWilliams identity, first found by Gluesing-Luerssen and Schneider, in the setting of classical convolutional codes. © 2014 IEEE

    A complete MacWilliams theorem for convolutional codes

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    © 2014 IEEE. In this paper, we prove a MacWilliams identity for the weight adjacency matrices based on the constraint codes of a convolutional code (CC) and its dual. Our result improves upon a recent result by Gluesing-Luerssen and Schneider, where the requirement of a minimal encoder is assumed. We can also establish the MacWilliams identity for the input-parity weight adjacency matrices of a systematic CC and its dual. Most importantly, we show that a type of Hamming weight enumeration functions of all codewords of a CC can be derived from the weight adjacency matrix, which thus provides a connection between these two very different notions of weight enumeration functions in the convolutional code literature. Finally, the relations between various enumeration functions of a CC and its dual are summarized in a diagram. This explains why no MacWilliams identity exists for the free-distance enumerators

    Barrier-Lyapunov-Function-Based Backstepping Adaptive Hybrid Force/Position Control for Manipulator with Force and Position Constraints

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    In this paper, we present a backstepping adaptive hybrid force/position control based on Barrier Lyapunov Function for a robotic manipulator to prevent constraint violation of applied force and position simultaneously. First, the task space is partitioned according to the constrained and unconstrained directions, and a new representation of dynamics is introduced. Next, force/position control is applied using the strict-feedback backstepping technique, in which a time-varying Barrier Lyapunov Function is employed to ensure that the force and position do not violate their constraints. Finally, to deal with uncertainty, disturbance and non-linearity of the system, an adaptive radial basis function neural network (RBFNN) is also implemented in the control algorithm. Stability proof of the proposed control method is presented, and simulation studies on a 2-link manipulator show the effectiveness as well as the performance of the proposed controller in preventing constraint violation

    Anomalous diffusivity and electric conductivity for low concentration electrolytes in nanopores

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    The dynamic properties of electrolytes in nanopores were studied using the equilibrium and non-equilibrium molecular dynamic simulations. The realistic primitive model and the restrictive primitive models that were widely used in liquid state theory were applied to the electrolyte model. The electrolytic ions that were found to be immersed in the water were treated as dielectric continuum or macroscopic dielectric continuum. Simulation studies for the discrete solvent primitive model were performed and detailed analysis of the characteristics of the ion radial density functions was done.published_or_final_versio

    Best practices in managing specialist subcontracting performance : final report

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    Construction Industry Institute-Hong Kong Report, no. 11Author name used in this publication: K T ChanAuthor name used in this publication: Edward YiuOther Versio

    Improved Performance of Amorphous InGaZnO Thin-Film Transistor with Ta2O5 Gate Dielectric by using La Incorporation

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    Argon laser peripheral iridoplasty (ALPI) versus systemic intraocular pressure lowering medications as the immediate management for phacomorphic angle closure

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    Poster Session: Glaucoma PhenotypesPurpose: To compare the efficacy and safety of argon laser peripheral iridoplasty (ALPI) to systemic intraocular pressure (IOP) lowering medications in the immediate management of phacomorphic angle closure. Patients and methods: This was a prospective randomized controlled study conducted at a district hospital in Hong Kong, China. Consecutive cases of phacomorphic angle closure were recruited from December 2009 to December 2010. Patients received intravenous (IV) and oral carbonic anhydrase inhibitor or ALPI as the initial treatment. IV mannitol was administered in both groups for presenting IOP > 60 mmHg or IOP > 40 mmHg 2 hours post treatment. The following perimeters were compared between the 2 arms: Snellen best correct visual acuity (BCVA); duration of symptoms; presenting IOP; IOP at 15 minutes, 30minutes and hourly after treatment until IOP < 25 mmHg; post-op angle, retinal nerve fibre layer (RNFL), endothelial count, BCVA and IOP. Results: Ten consecutive cases were included in the study. Six cases received medication therapy and 4 received ALPI. The mean age was 79.7 ± 7.2 in the medical therapy group and 78.3 ± 11.0 in the ALPI group. The presenting IOP was 50.7 ± 8.4 mmHg and 50.25 ± 6.9 mmHg in the medical therapy and ALPI group respectively. The duration of phacomorphic glaucoma in the medical group was 2.8 ± 3.5 days and 0.9 ± 0.25 days in the ALPI group. In the medical therapy group, 50% (3/6) required IV mannitol and none in the ALPI group. The time taken to reduce the presenting IOP to < 25 mmHg was 115.0 ± 97.0 minutes in the medical therapy group and 18.8 ± 7.5 minutes in the ALPI group. Within the first 30minutes, the drop in IOP was 20.8 ± 13.5mmHg in the medical group and 34.8 ± 3.2mmHg in the ALPI group, representing a 41.0% and 69.3% drop in IOP respectively. The degree of peripheral anterior synechiae (PAS) formation at 3 months was 45 ± 45.3° and 22.5 ± 5° in the medical and ALPI group respectively. The RNFL, angle, endothelial count, post-op VA and IOP were comparable in both groups. Conclusion: ALPI is an effective and safe IOP lowering modality in acute phacomorphic angle closure, offering a more rapid reduction of IOP, avoiding the use of systemic carbonic anhydrase inhibitor and hyperosmotic agents, and with seemingly less PAS formation and comparable post-op results as compared to medical therapy. ALPI should replace medical therapy as first line treatment in phacomorphic angle closure especially in elderly patients cannot tolerable the side effects of systemic IOP-lowering medication.published_or_final_versio

    Augmented reality in robot programming

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    Industrial robots have been traditionally programmed using teaching pendants, whereas offline programming methods are getting increasingly popular in recent years. Although the above two methods are widely-used in the industry, they both have certain disadvantages. For instance, the teaching pendant method requires a shutdown of the production line during the programming process, while offline programming method requires 3D CAD models of both the robot and the workpiece. In this paper, an augmented reality (AR) application which alleviates the aforementioned problems was proposed for robot programming purposes. The application is created using commercially available AR software, with the addition of our JavaScript code. The use of commercially available software allows an easier sharing and widespread adoption of the application

    High-mobility pentacene OTFT with TaLaO gate dielectric passivated by fluorine plasma

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    Pentacene thin-film transistor with high-κ TaLaO as gate dielectric has been fabricated and shows a carrier mobility of 0.73 cm2/V s, much higher than that based on pure La2O3 (0.43 cm2/V s) due to the smoother surface of the TaLaO film and thus larger pentacene islands grown on it in the initial stage. Moreover, among various times for fluorine-plasma treatment on the TaLaO gate dielectric, 100 seconds result in the highest carrier mobility of 1.12 cm2/V s due to (1) smoothest oxide surface achieved by fluorine passivation of oxide traps, as measured by AFM and supported by smallest sub-threshold swing and lowest low-frequency noise; (2) the largest pentacene grains grown on the smoothest oxide surface, as demonstrated by AFM. Pentacene islands on on TaLaO or La2O3 gate dielectric with different plasma treatment times.postprin
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