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Sample records for active defrost scheme

  1. An active defrost scheme with a balanced energy consumption and food quality loss in supermarket refrigeration systems

    DEFF Research Database (Denmark)

    Cai, Junping; Stoustrup, Jakob; Rasmussen, Bjarne Dindler

    2008-01-01

    This paper introduces food quality as a new parameter, together with energy, to determine an optimal cooling time between defrost cycles. A new defrost-on-demand scheme is proposed. It uses a feedback loop consisting of on-line model updating and estimation as well as a model based optimization. ...

  2. Activating the microscale edge effect in a hierarchical surface for frosting suppression and defrosting promotion.

    Science.gov (United States)

    Chen, Xuemei; Ma, Ruiyuan; Zhou, Hongbo; Zhou, Xiaofeng; Che, Lufeng; Yao, Shuhuai; Wang, Zuankai

    2013-01-01

    Despite extensive progress, current icephobic materials are limited by the breakdown of their icephobicity in the condensation frosting environment. In particular, the frost formation over the entire surface is inevitable as a result of undesired inter-droplet freezing wave propagation initiated by the sample edges. Moreover, the frost formation directly results in an increased frost adhesion, posing severe challenges for the subsequent defrosting process. Here, we report a hierarchical surface which allows for interdroplet freezing wave propagation suppression and efficient frost removal. The enhanced performances are mainly owing to the activation of the microscale edge effect in the hierarchical surface, which increases the energy barrier for ice bridging as well as engendering the liquid lubrication during the defrosting process. We believe the concept of harnessing the surface morphology to achieve superior performances in two opposite phase transition processes might shed new light on the development of novel materials for various applications.

  3. Minimizing quality deteriorations of refrigerated foodstuffs as a side effect of defrosting

    DEFF Research Database (Denmark)

    Cai, Junping; Stoustrup, Jakob

    2008-01-01

    This paper proposes an optimization scheme for traditional refrigeration systems with hysteresis controllers and scheduled defrosts. It aims at minimizing the side effect of defrost cycles on the storage quality of refrigerated foodstuffs in supermarkets. By utilizing the thermal mass of air...... and products inside a display cabinet, this optimization scheme forces the compressor to work harder and cool down more prior to the scheduled defrosts, thus guaranteeing the product temperature after defrost cycles still to be within a controlled safe level....

  4. Defrost Temperature Termination in Supermarket Refrigeration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

    2011-11-01

    The objective of this project was to determine the potential energy savings associated with implementing demand defrost strategies to defrost supermarket refrigerated display case evaporators, as compared to the widely accepted current practice of controlling display case defrost cycles with a preset timer. The defrost heater energy use of several representative display case types was evaluated. In addition, demand defrost strategies for refrigerated display cases as well as those used in residential refrigerator/freezers were evaluated. Furthermore, it is anticipated that future work will include identifying a preferred defrost strategy, with input from Retail Energy Alliance members. Based on this strategy, a demand defrost system will be designed which is suitable for supermarket refrigerated display cases. Limited field testing of the preferred defrost strategy will be performed in a supermarket environment.

  5. 9 CFR 590.538 - Defrosting facilities.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Defrosting facilities. 590.538 Section 590.538 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG..., and Facility Requirements § 590.538 Defrosting facilities. (a) Approved metal defrosting tanks or...

  6. Supermarket Defrost Cycles As Flexible Reserve

    DEFF Research Database (Denmark)

    Pedersen, Rasmus; Sloth, Christoffer; Wisniewski, Rafal

    2015-01-01

    This work analyses how supermarket defrost cycles can be used as flexible reserve in a smart grid context. The consumption flexibility originates from being able to shift defrost cycles in time, while adhering to the underlying refrigeration systems constraints. It is shown how this time constrai...

  7. Efficient defrosting of an inclined flat surface

    Energy Technology Data Exchange (ETDEWEB)

    Subrata Roy; Haribalan Kumar; Anderson, R. [Kettering University, Flint, MI (United States). Computational Plasma Dynamics Laboratory

    2005-06-01

    We present a deicing simulation for a practical three-dimensional geometry inside which hot air jets impinge upon a flat inclined glass surface with a layer of ice on the outside. The main goal is to study the unsteady two-phase melting process over the inclined flat surface, and to identify the traditional control parameters such as jet impingement angles for minimization of the defrosting time for given ice and glass thicknesses. A correlation for defrosting as functions of time, heat transfer parameters and impingement angles has been found. Also, in this study, the first Joule heating defroster using transparent electrodes are proposed and numerically simulated as a viable alternative. A correlation between the electrical Joule power requirement and the defrosting time is given. It is demonstrated that substantial improvements (roughly 70% reduction) in defrosting time may be achieved using Joule heating compared to the traditional jet impingement HVAC technology. (author)

  8. The Effect of Various Methods of Defrosting on Microbial Contamination of Frozen Banana Shrimp (Penaeus merguiensis)

    Institute of Scientific and Technical Information of China (English)

    Ladan Mansouri-Najand

    2012-01-01

    Objective: Background and aim: The most common and the best way of preventing microbial decay of marine foods is using freezing technology and the cycles and methods of defrosting have considerable effect on microbial changes of frozen shrimp. Shrimp is one of the marine foods that due to high active water (aw) and neutral PH and autolytic enzymes have high decay. Thus, in this study the effect of various methods of defrosts on microbial contamination of shrimp was investigated. Methods: This study was an empirical design on Penaeus merguiensis. The shrimps were divided into three groups including 1- peeled and headless (PUD), 2- Complete, 3- Headless (with skin) being frosted and defrosted in three cycles. Each group of shrimp was classified in terms of the type of defrosting method in three groups as 1- Microwave, 2- Refrigerator, 3-Water and were investigated in 3 cycles with the interval of 4 days. In this investigation, the total bacteria, Psychrophil bacteria, coliforms and Staphylococcus aureus were counted in private culture mediums. For data analysis, repeated measure Anova was used. Results: All the bacteria including Psychrophil bacteria, coliforms and Staphylococcus aureus during the cycles had significant reduction process and this reduction showed significant reduction in complete shrimp and defrosting with refrigerator compared to other groups (P<0.05). Conclusions: According to the results, complete shrimp was the best kind of shrimp in terms of microbial load. Thus, avoiding temperature changes during transportation and avoiding unduly defrosts in maintaining the quality of the frozen shrimp is proposed.

  9. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  10. Development of a demand defrost controller. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borton, D.N. [Power Kinetics, Troy, NY (United States); Walker, D.H. [Foster-Miller, Inc., Waltham, MA (United States)

    1993-10-01

    The purpose of this project was to develop and commercialize a demand defrost controller that initiates defrosts of refrigeration systems only when required. The standard method of control is a time clock that usually defrosts too often, which wastes energy. The controller developed by this project uses an algorithm based on the temperature difference between the discharge and return of the display case air curtain along with several time settings to defrost only when needed. This controller was field tested in a supermarket where it controlled defrost of the low-temperature display cases. According to test results the controller could reduce annual energy consumption by 20,000 and 62,000 kWh for hot gas and electric defrost, respectively. The controller saves electric demand as well as energy, is adaptable to ambient air conditions, and provides valuable savings throughout the year. The savings are greatest for low-temperature systems that use the most energy. A less tangible benefit of the demand controller is the improvement in food quality that results from fewer defrosts.

  11. Measured impacts of supermarket humidity level on defrost performance and refrigerating system energy use

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, H.I.; Khattar, M.

    1999-07-01

    This paper presents field-monitor data from two supermarkets where the impact of space humidity on refrigerating system energy use was evaluated. Direct digital control (DDC) systems were used at both stores to collect 15-minute monitored data. At Store A in Minneapolis, the DDC system was used to monitor system performance as well as to implement temperature-terminated control in place of time-terminated control on 16 refrigerated zones using hot gas defrost. At Store B in Indianapolis, the DDC system was used to quantify the performance trends for the single compressor rack system with electric defrost. The results at Store B showed that refrigerating system energy use decreases by nearly 10 kWh/day for each 1% drop in space relative humidity, or about 0.4% of average annual system energy use. This value includes the impact of reduced latent loads, the reduction in direct energy use and imposed load from reduced electric defrost heater operation, and the smaller imposed load from reduced anti-sweat heater energy use. The measured reductions agree well with the impact predicted using the calculation methods developed by Howell (1933b) in ASHRAE Research Project 596. At Store A, the measured data show that implementing temperature-terminated defrost reduced refrigerating system energy use by nearly 70 kWh/day over the winter period when the average space humidity was 22% RH. The savings from temperature-terminated defrost increase by 4 kWh/day per each 1% drop in relative humidity. At both stores, the same type of mechanical controls were used to duty cycle the anti-sweat heaters based on store dew point. Anti-sweat heater electricity use was observed to decrease by 4.6 kWh/day at Store B and 3.4 kWh/day at Store A for each 1% drop in relative humidity. At Store A, a more aggressive control scheme was implemented with the DDC system that reduced anti-sweat heater energy use by 7.8 kWh/day per % RH. The more aggressive control approach was reported to properly

  12. Frost formation and defrost control parameters for open multideck refrigerated food display cabinets

    Energy Technology Data Exchange (ETDEWEB)

    Tassou, S.A.; Datta, D. [Brunel Univ., Dept. of Mechanical Engineering, Uxbridge (United Kingdom); Marriott, D. [Safeway Stores plc, Hayes (United Kingdom)

    2001-04-03

    In order to achieve the required air and product temperatures in refrigerated food display cabinets, the evaporator coils, which are normally located in the base of the cabinets, operate at temperatures below the freezing point of water. The air which is circulated over the evaporator coil is cooled below its dew point and water vapour present in the air condenses and eventually freezes on the coil surface. With continuous operation of the coil, frost will accumulate on the coil surface leading to a decrease both in the air flowrate and in the overall heat transfer coefficient. In order to maintain satisfactory performance, evaporator coils are defrosted periodically. Although different defrost control strategies can be employed, for simplicity and cost considerations, defrosting in supermarket refrigeration systems is usually controlled by a pre-set time cycle. It is widely acknowledge, however, that time-based defrost may cause a number of unnecessary defrost cycles and this reduces the energy efficiency of the refrigeration systems as well as the accuracy of temperature control of the cabinets. Implementing defrost only when it is needed or on 'demand' should reduce the number of defrost cycles and lead to savings in energy and improved product quality. This paper reports on field and experimental investigations on the processes of frosting and defrosting of medium-temperature display cabinet evaporator coils. The results show that for medium-temperature refrigeration applications where the environment temperature is kept reasonably constant, the store humidity is the primary parameter influencing the rate of frost formation. Using relative humidity as a control parameter the defrost frequency can be reduced considerably without affecting cabinet performance and product integrity. Alongside the effect of relative humidity, the paper also considers the effects of other performance parameters on the processes of frosting and defrosting such as cooling

  13. Dynamics of Defrosting on Hydrophobic and Superhydrophobic Surfaces

    Science.gov (United States)

    Murphy, Kevin; McClintic, William; Lester, Kevin; Collier, Patrick; Boreyko, Jonathan

    2016-11-01

    It has recently been demonstrated that frost can grow in a suspended Cassie state on nanostructured superhydrophobic surfaces, which has implications for enhanced defrosting rates. However, to date there have been no direct comparisons of the defrosting kinetics of Cassie frost versus frost on conventional surfaces. Here, we fabricate a hybrid aluminum plate where half of the top face exhibits a superhydrophobic nanostructure while the other half is smooth and hydrophobic. By growing frost to varying thicknesses and melting at several tilt angles, we reveal the advantages and disadvantages of each surface with regards to the extent and speed of the shedding of melt water. For sufficiently thick frost layers, the Cassie state of frost on the superhydrophobic surface uniquely enabled the rapid and effective shedding of melt water even at low tilt angles. On the other hand, the hydrophobic surface was more effective at removing very thin frost sheets, as the reduced contact angle of water on the surface facilitated the coalescence of droplets to grow the melt water beyond the capillary length for gravitational removal. Therefore, the utilization of superhydrophobic versus hydrophobic surfaces for defrosting applications depends upon the context of the system conditions.

  14. An activation-recruitment scheme for use in muscle modeling.

    Science.gov (United States)

    Hawkins, D A; Hull, M L

    1992-12-01

    The derivation of a new activation-recruitment scheme and the results of a study designed to test its validity are presented. The activation scheme utilizes input data of processed surface EMG signals, muscle composition, muscle architecture, and experimentally determined activation coefficients. In the derivation, the relationship between muscle activation and muscle fiber recruitment was considered. In the experimental study, triceps muscle force was determined for isometric elbow extension tasks varying in intensity from 10 to 100% of a maximum voluntary contraction (MVC) using both a muscle model that incorporates the activation scheme, and inverse dynamics techniques. The forces calculated using the two methods were compared statistically. The modeled triceps force was not significantly different from the experimental results determined using inverse dynamics techniques for average activation levels greater than 25% of MVC, but was significantly different for activation levels less than 25% of MVC. These results lend support for use of the activation-recruitment scheme for moderate to large activation levels, and suggest that factors in addition to fiber recruitment play a role in force regulation at lower activation levels.

  15. 16 CFR Appendix B1 to Part 305 - Upright Freezers With Manual Defrost

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Upright Freezers With Manual Defrost B1 Appendix B1 to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC ACTS OF...) Pt. 305, App. B1 Appendix B1 to Part 305—Upright Freezers With Manual Defrost Range...

  16. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Science.gov (United States)

    2010-10-01

    ... defrosting and defogging systems. S1. Scope. This standard specifies requirements for windshield defrosting... passenger vehicles, trucks, and buses. S3. Definitions. Road load means the power output required to move a... driveline friction, rolling friction, and air resistance. S4. Requirements. (a) Except as provided...

  17. An active interferometer-stabilization scheme with linear phase control

    DEFF Research Database (Denmark)

    Vardhan Krishnamachari, Vishnu; Andresen, Esben Ravn; Potma, Eric Olaf

    2006-01-01

    We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....

  18. Design and Analysis of a Multiscale Active Queue Management Scheme

    Institute of Scientific and Technical Information of China (English)

    Qi-Jin Ji; Yong-Qiang Dong

    2006-01-01

    Since Internet is dominated by TCP-based applications, active queue management (AQM) is considered as an effective way for congestion control. However, most AQM schemes suffer obvious performance degradation with dynamic traffic. Extensive measurements found that Internet traffic is extremely bursty and possibly self-similar. We propose in this paper a new AQM scheme called multiscale controller (MSC) based on the understanding of traffic burstiness in multiple time scale. Different from most of other AQM schemes, MSC combines rate-based and queue-based control in two time scales. While the rate-based dropping on burst level (large time scales) determines the packet drop aggressiveness and is responsible for low and stable queuing delay, good robustness and responsiveness, the queue-based modulation of the packet drop probability on packet level (small time scales) will bring low loss and high throughput. Stability analysis is performed based on a fluid-flow model of the TCP/MSC congestion control system and simulation results show that MSC outperforms many of the current AQM schemes.

  19. Schemes for applying active lubrication to main engine bearings

    DEFF Research Database (Denmark)

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    The work presented here is a theoretical study that describes two different schemes for the oil injection system in actively lubricated main engine bearings. The use of active lubrication in journal bearings helps to enhance the hydrodynamic fluid film by increasing the fluid film thickness...... orifices circumferentially located around the bearing surface. The pressure distribution of the hydrodynamic fluid film in journal bearings is governed by the Reynolds equation, which is modified to accommodate the dynamics of active lubrication, and which can be numerically solved using finite......-difference method. The computed bearing fluid film forces are coupled to the set of nonlinear equations that describes the dynamics of the reciprocating engine, obtained with the help of multibody dynamics (rigid components) and finite elements method (flexible components). The main equations that govern...

  20. Influence of supermarket environmental parameters on the frosting and defrosting of vertical multideck display cabinets

    Energy Technology Data Exchange (ETDEWEB)

    Tassou, S.A.; Datta, D.

    1999-07-01

    This paper reports on results of investigations to identify and quantify the effect of in-store environmental conditions on frost accumulation on the evaporator coils of open multideck refrigerated display cabinets. Field and environmental chamber-based tests have shown that both ambient relative humidity and temperature of a store have a significant effect on the rate of frost formation on the evaporator coils, with the effect of relative humidity being much more pronounced than the effect of temperature. In supermarkets where a fixed-time defrost control strategy is employed, it is possible that cabinets are defrosted too infrequently at high relative humidities, resulting in high product temperatures, and too frequently at low relative humidities, resulting in excessive energy consumption. Considerable opportunity exists for the application of more sophisticated defrost control strategies, both to save energy and improve temperature control.

  1. A new numerical scheme for the simulation of active magnetic regenerators

    DEFF Research Database (Denmark)

    Torregrosa-Jaime, B.; Engelbrecht, Kurt; Payá, J.;

    2014-01-01

    A 1D model of a parallel-plate active magnetic regenerator (AMR) has been developed based on a new numerical scheme. With respect to the implicit scheme, the new scheme achieves accurate results, minimizes computational time and prevents numerical errors. The model has been used to check the boun...

  2. 16 CFR Appendix A3 to Part 305 - Refrigerator-Freezers With Partial Automatic Defrost

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Refrigerator-Freezers With Partial Automatic Defrost A3 Appendix A3 to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER... LABELING RULEâ) Pt. 305, App. A3 Appendix A3 to Part 305—Refrigerator-Freezers With Partial...

  3. Modelling and experimental validation of the hot-gas defrost process of an air-cooled evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Dopazo, J. Alberto; Fernandez-Seara, Jose; Uhia, Francisco J.; Diz, Ruben [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No 9, 36310 Vigo, Pontevedra (Spain)

    2010-06-15

    A detailed transient simulation model has been developed to predict and evaluate the performance of the hot-gas defrost process of an air-coil evaporator. In the model, the defrost process is subdivided into six stages: preheating, tube frost melting start, fin frost melting start, air presence, tube-fin water film and dry-heating. In each stage, the control volume is subdivided into systems represented by a single node, which has the representative properties of the system. A finite difference approach was used to solve the model equations. The results include the time required to defrost, the distribution of the energy during defrost process, the instantaneous refrigerant properties and the instantaneous fin and tube temperature distribution. The results are compared with experimental data obtained in a local storage facility under actual operating conditions and also using data available in the literature. The model results substantially agree with the experimental data in both cases. (author)

  4. An implicit evolution scheme for active contours and surfaces based on IIR filtering.

    Science.gov (United States)

    Delibasis, Konstantinos K; Asvestas, Pantelis A; Kechriniotis, Aristides I; Matsopoulos, George K

    2014-05-01

    In this work, we present an approach for implementing an implicit scheme for the numerical solution of the partial differential equation of the evolution of an active contour/surface. The proposed scheme is applicable to any variant of the traditional active contour (AC), irrespectively of the calculation of the image-based force field and it is readily applicable to explicitly parameterized active surfaces (AS). The proposed approach is formulated as an infinite impulse response (IIR) filtering of the coordinates of the contour/surface points. The poles of the filter are determined by the parameters controlling the shape of the active contour/surface. We show that the proposed IIR-based implicit evolution scheme has very low complexity. Furthermore, the proposed scheme is numerically stable, thus it allows the convergence of the AC/AS with significantly fewer iterations than the explicit evolution scheme. It also possesses the separability property along the two parameters of the AS, thus it may be applied to deformable surfaces, without the need to store and invert large sparse matrices. We implemented the proposed IIR-based implicit evolution scheme in the Vector Field Convolution (VFC) AC/AS using synthetic and clinical volumetric data. We compared the segmentation results with those of the explicit AC/AS evolution, in terms of accuracy and efficiency. Results show that the VFC AC/AS with the proposed IIR-based implicit evolution scheme achieves the same segmentation results with the explicit scheme, with considerably less computation time.

  5. An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

    DEFF Research Database (Denmark)

    Torregrosa-Jaime, Bárbara; Corberán, José M.; Payá, Jorge;

    2015-01-01

    A one-dimensional model of a parallel-plate active magnetic regenerator (AMR) is presented in this work. The model is based on an efficient numerical scheme which has been developed after analysing the heat transfer mechanisms in the regenerator bed. The new finite difference scheme optimally...

  6. Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme

    Directory of Open Access Journals (Sweden)

    Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin

    2012-08-01

    Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words:  Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.

  7. Demonstration of a 4-Sensor Folded Sangac Sensor Array with Active Phase Biasing Scheme

    Institute of Scientific and Technical Information of China (English)

    Zhang-Qi Song; Ming-Ye Yang; Xue-Liang Zhang; Yong-Ming Hu

    2008-01-01

    A 4-sensor folded Sagnae sensor array with an active phase biasing scheme is presented. The overlapping of the signal and noise pulse is avoided through a time division multiplexing scheme and the noise pulses is eliminated almost completely. The scheme can address 16 sensors when the repeat frequency of input pulse is at 68.3 kHz. The alternative phase bias technique is demonstrated, which can provide sensors with stable phase bias. The future benefit of this technique is that the 1/f noise in the circuit can be suppressed.

  8. A Lightning Activity Forecast Scheme Developed for Summer Thunderstorms in South China

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; ZHANG Yijun; DONG Wansheng

    2010-01-01

    Based on the relationship between lightning flash density and radar echoes and a statistical analysis using satellite and radar observations,a scheme was introduced into the mesoscale model GRAPES(Global and Regional Assimilation and PrEdiction System)to forecast the cloud to ground(CC)flash activities.Because the relationship is a necessary but not sufficient condition for lightning,an additional constraint condition related to temperature of cloud top is added into the scheme to determine whether the lightning activity really occurs.Only if the lightning activity meets the criterion to occur,the CG flash density in a grid is considered to be valid.This was proved to be necessary for reducing the false prediction.Two cases that occurred on the edge of the subtropical high in coastal regions of South China were simulated to examine the efficiency of the scheme.The results showed that the scheme was capable of forecasting lightning activities in South China.The simulated lightning areas agreed with the CG flash observations,and the CG flash density forecast by the model was also consistent with observational results in magnitude.In consideration of the forecast aging of the explicit cloud microphysical scheme in GRAPES,lightning activities can now be forecast accurately within 6 h.

  9. Comparative Study between Two Schemes of Active-Control-Based Mechatronic Inerter

    Directory of Open Access Journals (Sweden)

    He Lingduo

    2017-01-01

    Full Text Available Based on force-current analogy and velocity-voltage analogy in the theory of electromechanical analogy, the inerter is a device that corresponded to the capacitor completely where conquers the nature restriction of mass, what’s more, it is significant to improve the ratio of the inerter’s inertance to its mass for mechanical networks synthesis. And according to the principle of active-control-based mechatronic inerter, we present two implementation schemes. One was based on linear motor, and the other was based on the ball screw and rotary motor. We introduced the implementation methods and established theoretical model of the two schemes, then compared the ratio of the inerter’s inertance to its mass for the two schemes. Finally, we consider the scheme is better which was based on the ball screw and rotary motor.

  10. Does Mixed Reimbursement Schemes Affect Hospital Activity and Productivity? An Analysis of the Case of Denmark

    DEFF Research Database (Denmark)

    Hansen, Xenia Brun; Bech, Mickael; Jakobsen, Mads Leth;

    2013-01-01

    The majority of public hospitals in Scandinavia are reimbursed through a mixture of two prospective reimbursement schemes, block grants (a fixed amount independent of the number of patients treated) and activity-based financing (ABF). This article contributes theoretically to the existing...... whether different incentives affects the performance of hospitals regarding activity and productivity differently. Information on Danish reimbursement schemes has been collected from documents provided by the regional governments and through interviews with regional administrations. The data cover...... and region we show that there have not been any significant changes in the number of hospital discharges for any of the regions from 2007 to 2010 within any of the treatment groups....

  11. Smartphone-Based Patients' Activity Recognition by Using a Self-Learning Scheme for Medical Monitoring.

    Science.gov (United States)

    Guo, Junqi; Zhou, Xi; Sun, Yunchuan; Ping, Gong; Zhao, Guoxing; Li, Zhuorong

    2016-06-01

    Smartphone based activity recognition has recently received remarkable attention in various applications of mobile health such as safety monitoring, fitness tracking, and disease prediction. To achieve more accurate and simplified medical monitoring, this paper proposes a self-learning scheme for patients' activity recognition, in which a patient only needs to carry an ordinary smartphone that contains common motion sensors. After the real-time data collection though this smartphone, we preprocess the data using coordinate system transformation to eliminate phone orientation influence. A set of robust and effective features are then extracted from the preprocessed data. Because a patient may inevitably perform various unpredictable activities that have no apriori knowledge in the training dataset, we propose a self-learning activity recognition scheme. The scheme determines whether there are apriori training samples and labeled categories in training pools that well match with unpredictable activity data. If not, it automatically assembles these unpredictable samples into different clusters and gives them new category labels. These clustered samples combined with the acquired new category labels are then merged into the training dataset to reinforce recognition ability of the self-learning model. In experiments, we evaluate our scheme using the data collected from two postoperative patient volunteers, including six labeled daily activities as the initial apriori categories in the training pool. Experimental results demonstrate that the proposed self-learning scheme for activity recognition works very well for most cases. When there exist several types of unseen activities without any apriori information, the accuracy reaches above 80 % after the self-learning process converges.

  12. Simultaneous Manipulation of Electric and Thermal Fields via Combination of Passive and Active Schemes

    CERN Document Server

    Lan, Chuwen; Zhou, Ji

    2015-01-01

    Increasing attention has been focused on the invisibility cloak due to its novel concept for manipulation of physical field. However, it is usually realized by single scheme (namely passive or active scheme) and limited in a single field. Here, we proposed a general method to achieve simultaneous manipulation of multi-physics field via combination of passive and active schemes. Experimentally, this method was demonstrated by simultaneous manipulation of electric field and thermal field. Firstly, a device was designed to simultaneously behave as electric and thermal invisibility cloak. Secondly, another device was demonstrated to simultaneously behave as electric invisibility cloak and thermal concentrator. The experimental results agree well with the simulated ones, thus confirming the feasibility of our method. Our method can also be extended to the other multi-physics fields, which would create much more freedom to design of new system and might enable new potential application in broad areas.

  13. Activation energy of thermoluminescence glow curves in a hyperbolic heating scheme

    Energy Technology Data Exchange (ETDEWEB)

    Shambhunath Singh, W. [Manipur College, Imphal (India). Dept. of Physics; Dorendrajit Singh, S.; Mazumdar, P.S. [Manipur Univ. (India). Dept. of Physics; Deb, N.C. [Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Theoretical Physics

    1997-04-07

    We present a set of expressions for the determination of the activation energy of a thermoluminescence peak recorded with a hyperbolic heating scheme. It is demonstrated that the order of kinetics can be estimated from the fractional intensities at the points of inflection of the peak. (author).

  14. Design and Performance Research of a Chaotic Secure Communication Scheme Based on Active-Passive Synchronization

    Institute of Scientific and Technical Information of China (English)

    ZHANGXingzhou; SONGChunyan; QIAOYulong

    2005-01-01

    A new scheme of chaotic secure communication based on active-passive synchronization is proposed.Not only the complexity of system is reduced, but also the capability is enhanced. At the same time, it does not destroy the correlation. The experimental results show that the proposed method can recover signals well. Because the system is very sensitive to the parameters, which reaches the level of asynchronous method, and it can resist the attack of decryption methods to chaotic synchronization, the scheme is safe.

  15. Interleaved Buck Converter with Variable Number of Active Phases and a Predictive Current Sharing Scheme

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Garcia, O.; Oliver, J. A.

    2008-01-01

    The efficiency of an interleaved Buck converter is typically low at light load conditions because of the switching losses in each of the switching stages. Improvements in the converter efficiency can be achieved by dynamically changing the number of active phases depending on the load current. Th...... and shows that the predictive current equalisation scheme can equalise the phase currents in a single PWM period....

  16. Electronic temperatures of terahertz quantum cascade active regions with phonon scattering assisted injection and extraction scheme.

    Science.gov (United States)

    Patimisco, Pietro; Scamarcio, Gaetano; Santacroce, Maria Vittoria; Spagnolo, Vincenzo; Vitiello, Miriam Serena; Dupont, Emmanuel; Laframboise, Sylvain R; Fathololoumi, Saeed; Razavipour, Ghasem S; Wasilewski, Zbigniew

    2013-04-22

    We measured the lattice and subband electronic temperatures of terahertz quantum cascade devices based on the optical phonon-scattering assisted active region scheme. While the electronic temperature of the injector state (j = 4) significantly increases by ΔT = T(e)(4) - T(L) ~40 K, in analogy with the reported values in resonant phonon scheme (ΔT ~70-110 K), both the laser levels (j = 2,3) remain much colder with respect to the latter (by a factor of 3-5) and share the same electronic temperature of the ground level (j = 1). The electronic population ratio n(2)/n(1) shows that the optical phonon scattering efficiently depopulates the lower laser level (j = 2) up to an electronic temperature T(e) ~180 K.

  17. Agent-based power sharing scheme for active hybrid power sources

    Science.gov (United States)

    Jiang, Zhenhua

    The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

  18. Screening for proteolytic activities in snake venom by means of a multiplexing electrospray ionization mass spectrometry assay scheme

    NARCIS (Netherlands)

    Liesener, André; Perchuc, Anna-Maria; Schöni, Reto; Wilmer, Marianne; Karst, Uwe

    2005-01-01

    A multiplexed mass spectrometry based assay scheme for the simultaneous determination of five different substrate/product pairs was developed as a tool for screening of proteolytic activities in snake venom fractions from Bothrops moojeni. The assay scheme was employed in the functional characteriza

  19. Novel active fault-tolerant control scheme and its application to a double inverted pendulum system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    On the basis of the gain-scheduled H∞ design strategy,a novel active fault-tolerant control scheme is proposed.Under the assumption that the effects of faults on the state-space matrices of systems can be of affine parameter dependence,a reconfigurable robust H∞ linear parameter varying controller is developed.The designed controller is a function of the fault effect factors that can be derived online by using a well-trained neural network.To demonstrate the effectiveness of the proposed method,a double inverted pendulum system,with a fault in the motor tachometer loop,is considered.

  20. The unrealised potential of bike share schemes to influence population physical activity levels - A narrative review.

    Science.gov (United States)

    Bauman, Adrian; Crane, Melanie; Drayton, Bradley Alan; Titze, Sylvia

    2017-02-20

    The recent proliferation of bike share schemes (BSS, also known as public bicycle use programs) in many cities has focused attention on their potential for reducing motorised traffic congestion, improving air quality and reducing car use. Since 2005, hundreds of bike share schemes have been implemented in many cities, with bike share usage patterns monitored in many of them. This paper assesses the development of BSS and provides a rationale for their potential health benefits. The key research question, as yet unanswered, is whether BSS themselves can contribute to improving population health, particularly through increasing population cycling, which would increase population levels of health-enhancing physical activity. This paper presents a framework for evaluating the contribution of BSS to population physical activity, and uses examples of new data analyses to indicate the challenges in answering this question. These illustrative analyses examine cycling in Australia, and [i] compares rates of cycling to work in BSS cities compared to the rest of Australia over time, and [ii] modelling trends in bike counts in Central Melbourne before and after introduction of the BSS in 2010, and compared to adjacent regions in nearby suburbs unexposed to a BSS. These indicative examples point to difficulties in attributing causal increases in cycling for transport to the introduction of a BSS alone. There is an evidence gap, and a need to identify opportunities to improve the health-related components of BSS evaluations, to answer the question whether they have any impact on population physical activity levels.

  1. 汽车除霜系统性能CFD分析与试验%The CFD Analysis and Experiment for Automotive Defrost System Performance

    Institute of Scientific and Technical Information of China (English)

    王俊; 陈如意

    2011-01-01

    依据CAD数据和其他分析所需数据,进行了3个阶段的CFD除霜性能分析,除霜风道分析、稳态流场分析和瞬态除霜分析.依据布置和接口来设计风道,掌控各个出风口的流量分配.通过稳态计算来预测汽车空调的除霜性能并进行了验算.用瞬态模拟获得前挡风玻璃上随时间变化的除霜效果表明,除霜面积和形状与试验结果相符,试验除霜速度稍快于CFD计算的除霜速度.%CFD defrosting performance analysis, defrosting wind tunnel analysis, steady state flow field analysis and transient state defrosting analysis of three phases were made based on CAD data and other data needed in analysis. Wind tunnel is designed according to layout and interface,to control air flow distribution in each air outlet. Defrosting performance of air conditioner is predicated by steady state calculation.The defrosting effect of front windshield which changes with time obtained with transient state simulation indicates that the defrosting area and shape are consistent with test results, the test defrosting speed is slightly faster than the one with CFD calculation.

  2. A New Decoding Scheme for Errorless Codes for Overloaded CDMA with Active User Detection

    CERN Document Server

    Mousavi, Ali; Marvasti, Farokh

    2010-01-01

    Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA [1]. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme of coding/decoding show impressive performance, the decoder can be improved. In this paper by assuming more practical conditions for the traffic in the system, we suggest an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of 400 in some Eb/N0's The algorithm supposes the Poison distribution for the time of activation/deactivation of the users.

  3. Performance Analysis Of Active Queue Management AQM In VOIP Using Different Voice Encoder Scheme

    Directory of Open Access Journals (Sweden)

    Samir Eid Mohammed

    2015-08-01

    Full Text Available Abstract Voice over Internet Protocol VoIP is a rapidly growing technology that enables transport of voice over data networks such as Ethernet Wide area networks WANs due to this important different codec scheme is developed to meet the QoS requirements. This thesis presents a comprehensive study about the impact of active queue management AQM on Voice over Internet Protocol VoIP quality of service using different codec scheme such as G711 G723 G729 and GSM using simulations tools. The evaluation is done using the OPNET Modeler which provides a convenient and easy-to-use platform for simulating large scale networks and this also give a power to go through different levels of designing a network even with the ability to program the mechanism you want which is used here to implement two types of AQM mechanism which is not included by default in the OPNET and these two mechanisms are ARED and GRED. The performance metrics used in the study are jitter throughput and delay. The study shows that G.711 and G729 codecs in a simulation gives a significant result for the performance of VoIP that codec G711 and G.729A has acceptable throughput and less deviation of received to transmit packet as compared to GSM and G.723 also average delay like end to end delay and Voice jitter is lesser in codec G711 and G.729 as compared to the other two referenced codecs.

  4. Defrosting the digital library: bibliographic tools for the next generation web.

    Science.gov (United States)

    Hull, Duncan; Pettifer, Steve R; Kell, Douglas B

    2008-10-01

    Many scientists now manage the bulk of their bibliographic information electronically, thereby organizing their publications and citation material from digital libraries. However, a library has been described as "thought in cold storage," and unfortunately many digital libraries can be cold, impersonal, isolated, and inaccessible places. In this Review, we discuss the current chilly state of digital libraries for the computational biologist, including PubMed, IEEE Xplore, the ACM digital library, ISI Web of Knowledge, Scopus, Citeseer, arXiv, DBLP, and Google Scholar. We illustrate the current process of using these libraries with a typical workflow, and highlight problems with managing data and metadata using URIs. We then examine a range of new applications such as Zotero, Mendeley, Mekentosj Papers, MyNCBI, CiteULike, Connotea, and HubMed that exploit the Web to make these digital libraries more personal, sociable, integrated, and accessible places. We conclude with how these applications may begin to help achieve a digital defrost, and discuss some of the issues that will help or hinder this in terms of making libraries on the Web warmer places in the future, becoming resources that are considerably more useful to both humans and machines.

  5. Defrosting the digital library: bibliographic tools for the next generation web.

    Directory of Open Access Journals (Sweden)

    Duncan Hull

    2008-10-01

    Full Text Available Many scientists now manage the bulk of their bibliographic information electronically, thereby organizing their publications and citation material from digital libraries. However, a library has been described as "thought in cold storage," and unfortunately many digital libraries can be cold, impersonal, isolated, and inaccessible places. In this Review, we discuss the current chilly state of digital libraries for the computational biologist, including PubMed, IEEE Xplore, the ACM digital library, ISI Web of Knowledge, Scopus, Citeseer, arXiv, DBLP, and Google Scholar. We illustrate the current process of using these libraries with a typical workflow, and highlight problems with managing data and metadata using URIs. We then examine a range of new applications such as Zotero, Mendeley, Mekentosj Papers, MyNCBI, CiteULike, Connotea, and HubMed that exploit the Web to make these digital libraries more personal, sociable, integrated, and accessible places. We conclude with how these applications may begin to help achieve a digital defrost, and discuss some of the issues that will help or hinder this in terms of making libraries on the Web warmer places in the future, becoming resources that are considerably more useful to both humans and machines.

  6. The destructive negative binomial cure rate model with a latent activation scheme.

    Science.gov (United States)

    Cancho, Vicente G; Bandyopadhyay, Dipankar; Louzada, Francisco; Yiqi, Bao

    2013-07-01

    A new flexible cure rate survival model is developed where the initial number of competing causes of the event of interest (say lesions or altered cells) follow a compound negative binomial (NB) distribution. This model provides a realistic interpretation of the biological mechanism of the event of interest as it models a destructive process of the initial competing risk factors and records only the damaged portion of the original number of risk factors. Besides, it also accounts for the underlying mechanisms that leads to cure through various latent activation schemes. Our method of estimation exploits maximum likelihood (ML) tools. The methodology is illustrated on a real data set on malignant melanoma, and the finite sample behavior of parameter estimates are explored through simulation studies.

  7. Half-Duplex Active Eavesdropping in Fast Fading Channels: A Block-Markov Wyner Secrecy Encoding Scheme

    CERN Document Server

    Amariucai, George T

    2010-01-01

    In this paper we study the problem of half-duplex active eavesdropping in fast fading channels. The active eavesdropper is a more powerful adversary than the classical eavesdropper. It can choose between two functional modes: eavesdropping the transmission between the legitimate parties (Ex mode), and jamming it (Jx mode) -- the active eavesdropper cannot function in full duplex mode. We consider a conservative scenario, when the active eavesdropper can choose its strategy based on the legitimate transmitter-receiver pair's strategy -- and thus the transmitter and legitimate receiver have to plan for the worst. We show that conventional physical-layer secrecy approaches perform poorly (if at all), and we introduce a novel encoding scheme, based on very limited and unsecured feedback -- the Block-Markov Wyner (BMW) encoding scheme -- which outperforms any schemes currently available.

  8. An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei;

    2016-01-01

    Traditional droop-controlled systems assume that the generators are able to provide sufficient power as required. This is however not always true, especially in renewable systems, where the energy sources (e.g., photovoltaic source) may not be able to provide enough power (or even loss of power......-stage photovoltaic (PV) system has not been considered. In this paper, an enhanced droop scheme is thus proposed to address those issues, and the proposed scheme can enable resilient active power sharing in parallel two-stage PV inverter systems. Furthermore, a small-signal analysis for the proposed droop control...

  9. Models of the Optical/Ultraviolet Continuum Polarization in Active Galactic Nuclei: Implications for Unification Schemes

    Science.gov (United States)

    Kartje, John F.

    1995-10-01

    I have computed the 1200-8000 A thermal continuum polarization induced by gas and dust arranged in configurations compatible with current active galactic nuclei (AGNs) unification schemes. Both uniform- density tori and stratified-density disk-driven winds were considered. A Monte Carlo radiative transfer code was developed which includes the polarization mechanisms of electron and dust scattering as well as dichroic extinction by aligned grains. A Galactic-type grain population was assumed. Based on these calculations, I propose a new interpretation of many of the observed polarization traits of Seyfert galaxies and QSOs: namely, that the polarization in these sources is induced by the same optically thick material which is assumed to obscure the central engine in unification schemes. In particular, I suggest that stratified-density winds could provide a natural explanation (and one consistent with unification models) of the polarization trends observed in Seyfert galaxies. Such winds can display polarizations (P ≲ 20%) oriented perpendicular to the axis along viewing angles inclined to the axis by θ0 ≳ 45° in well-collimated winds, this polarization shifts to smaller magnitudes (P ≲ 2%) and parallel orientations for more face-on viewing, consistent with the patterns observed in Seyfert 2 and Seyfert 1 sources, respectively. In less-collimated winds, scattering alone tends to produce parallel orientations for all viewing angles; perpendicular polarization at large θ0 can result if there is a high degree of magnetic grain alignment. The simplest torus models (i.e., uniform-density, opaque gas and dust) do not reproduce this flip in polarization position angle. Furthermore, they generally display high polarization magnitudes (P ≳ 10%) along most viewing angles θ0 > θ∞ (where θ is the torus half-opening angle) and negligible polarization along θ0 > θ∞. Unlike previous models for AGN polarization which invoke scattering by optically thin electron

  10. Developing a Coding Scheme to Analyse Creativity in Highly-constrained Design Activities

    DEFF Research Database (Denmark)

    Dekoninck, Elies; Yue, Huang; Howard, Thomas J.;

    2010-01-01

    of design and analysis on a highly constrained design task. This paper shows how design changes can be coded using a scheme based on creative ‘modes of change’. The coding scheme can show the way a designer moves around the design space, and particularly the strategies that are used by a creative designer......This work is part of a larger project which aims to investigate the nature of creativity and the effectiveness of creativity tools in highly-constrained design tasks. This paper presents the research where a coding scheme was developed and tested with a designer-researcher who conducted two rounds...... to skip from one ‘train of solutions’ to new avenues. The coding scheme can be made more robust by: ensuring design change is always coded relative to a reference design; tightening up definitions of ‘system’, ‘element’ and ‘function’; and using a matrix to develop a more complete set of codes. A much...

  11. An active 3-dimensional localization scheme for femtocell subscribers using E-UTRAN

    KAUST Repository

    Mohammed, Aquil Mirza

    2012-05-01

    Femtocells provide an efficient solution to overcome the indoor coverage problems and also to deal with the traffic within Macro cells. The possibility of localizing femtocell subscriber stations based on the timing ranging advance parameter (TRAP), obtained from E-UTRAN (Evolved UMTS Terrestrial Radio Access Network), within the network signal internals is challenging and is studied throughout in this paper. The principle approach to localization based on Euclidean distances from multiple base stations is outlined.We investigate the specifications of the timing parameters or TRAP used for air interface of 4G network as they relate to calculating the subscriber distances. Computer simulation is used to demonstrate the localization accuracy using multiple base station networks when estimating likely locations of femtocell subscribers stations on a twodimensional coordinate mapping system. However, we further extend our simulations to demonstrate expected location accuracy of subscriber stations, for multiple base station networks, on a three dimensional coordinate mapping scheme. The possibility of of error-fixes shows eight times greater accuracy than in previous results is expected to achieve by applying timing advance techniques to Global System for Mobile communications networks, by using a two-dimensional coordinate mapping scheme. We later compare our study with the effect of global positioning system (GPS) by using a three-dimensional coordinate mapping scheme, which is predicted to give an 72.4 cms accuracy of subscriber station location. © 2012 IEEE.

  12. Source Driver Channel Reduction Schemes Employing Corresponding Pixel Alignments for Current Programming Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Hong, Soon-Kwang; Oh, Du-Hwan; Jeong, Seok-Hee; Park, Young-Ju; Kim, Byeong-Koo; Ha, Yong-Min; Jang, Jin

    2008-03-01

    We propose two types of novel scheme for reducing the number of output channels of driver-integrated circuit (D-IC) for the current programming compensation pixel structures of active-matrix organic light-emitting diodes (AMOLEDs). One is a 2:1 data demultiplexing technique that can reduce the number of output channels of D-IC by half. The proposed second scheme is a vertically aligned red (R), green (G), and blue (B) subpixel scheme instead of a horizontally aligned R-G-B subpixel one, which is regarded as the conventional pixel alignment scheme. We have also successfully implemented these schemes in a 2.4-in.-sized QCIF + (176 × RGB × 220) AMOLED using p-type excimer laser annealing (ELA) low-temperature polycrystalline silicon (LTPS) technology and evaluated key performance characteristics.

  13. Robust and fast schemes in broadband active noise and vibration control

    NARCIS (Netherlands)

    Fraanje, Petrus Rufus

    2004-01-01

    This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods.

  14. Automated segmentation of the quadratus lumborum muscle from magnetic resonance images using a hybrid atlas based - geodesic active contour scheme.

    Science.gov (United States)

    Jurcak, V; Fripp, J; Engstrom, C; Walker, D; Salvado, O; Ourselin, S; Crozier, S

    2008-01-01

    This study presents a novel method for the automatic segmentation of the quadratus lumborum (QL) muscle from axial magnetic resonance (MR) images using a hybrid scheme incorporating the use of non-rigid registration with probabilistic atlases (PAs) and geodesic active contours (GACs). The scheme was evaluated on an MR database of 7mm axial images of the lumbar spine from 20 subjects (fast bowlers and athletic controls). This scheme involved several steps, including (i) image pre-processing, (ii) generation of PAs for the QL, psoas (PS) and erector spinae+multifidus (ES+MT) muscles and (iii) segmentation, using 3D GACs initialized and constrained by the propagation of the PAs using non-rigid registration. Pre-processing of the images involved bias field correction based on local entropy minimization with a bicubic spline model and a reverse diffusion interpolation algorithm to increase the slice resolution to 0.98 x 0.98 x 1.75mm. The processed images were then registered (affine and non-rigid) and used to generate an average atlas. The PAs for the QL, PS and ES+MT were then generated by propagation of manual segmentations. These atlases were further analysed with specialised filtering to constrain the QL segmentation from adjacent non-muscle tissues (kidney, fat). This information was then used in 3D GACs to obtain the final segmentation of the QL. The automatic segmentation results were compared with the manual segmentations using the Dice similarity metric (DSC), with a median DSC for the right and left QL muscles of 0.78 (mean = 0.77, sd=0.07) and 0.75 (mean =0.74, sd=0.07), respectively.

  15. Construction of Z-scheme Ag2CO3/N-doped graphene photocatalysts with enhanced visible-light photocatalytic activity by tuning the nitrogen species

    Science.gov (United States)

    Song, Shaoqing; Meng, Aiyun; Jiang, Shujuan; Cheng, Bei; Jiang, Chuanjia

    2017-02-01

    Semiconductor-based photocatalysis has great potential in various environmental and energy applications, and Z-scheme photocatalysts have many advantages over single-component photocatalysts. The construction of a highly efficient Z-scheme photocatalytic system depends on the geometric structure arrangement, microscopic and crystalline form of the stoichiometric species, and it has not been elucidated whether the Z-scheme photocatalysts can be designed by tuning the electronic structures of cocatalysts alone. Here, using N-doped graphene (NG) as cocatalyst, we successfully constructed Z-scheme Ag2CO3-NG photocatalysts with enhanced activity for the photooxidative degradation of phenol pollutant. It was found that the pyridinic nitrogen species (Np) of NG could spontaneously reduce Ag+ to produce plasmonic Ag nanoparticles on Ag2CO3-NG, while the efficiency of the photogenerated charge separation, Z-scheme transfer option, and O2 adsorption were promoted by the graphitic nitrogen species (Ng). Therefore, the as-designed Z-scheme Ag2CO3-NG photocatalysts showed much higher activity than Ag2CO3 and its composites with graphene oxide (GO) or reduced GO as cocatalysts in the photocatalytic degradation of phenol. Hence, our results provide a new strategy for exploring advanced Z-scheme photocatalysts with NG as cocatalyst by rationally tuning the Np and Ng species.

  16. Physical activity on prescription schemes (PARS): do programme characteristics influence effectiveness? Results of a systematic review and meta-analyses

    Science.gov (United States)

    Arsenijevic, Jelena; Groot, Wim

    2017-01-01

    Background Physical activity on prescription schemes (PARS) are health promotion programmes that have been implemented in various countries. The aim of this study was to outline the differences in the design of PARS in different countries. This study also explored the differences in the adherence rate to PARS and the self-reported level of physical activity between PARS users in different countries. Method A systematic literature review and meta-analyses were conducted. We searched PubMed and EBASCO in July 2015 and updated our search in September 2015. Studies that reported adherence to the programme and self-reported level of physical activity, published in the English language in a peer-reviewed journal since 2000, were included. The difference in the pooled adherence rate after finishing the PARS programme and the adherence rate before or during the PARS programme was 17% (95% CI 9% to 24%). The difference in the pooled physical activity was 0.93 unit score (95 CI −3.57 to 1.71). For the adherence rate, a meta-regression was conducted. Results In total, 37 studies conducted in 11 different countries met the inclusion criteria. Among them, 31 reported the adherence rate, while the level of physical activity was reported in 17 studies. Results from meta-analyses show that PARS had an effect on the adherence rate of physical activity, while the results from the meta-regressions show that programme characteristics such as type of chronic disease and the follow-up period influenced the adherence rate. Conclusions The effects of PARS on adherence and self-reported physical activity were influenced by programme characteristics and also by the design of the study. Future studies on the effectiveness of PARS should use a prospective longitudinal design and combine quantitative and qualitative data. Furthermore, future evaluation studies should distinguish between evaluating the adherence rate and the self-reported physical activity among participants with different

  17. The theoretical research on pneumatic defrosting of t'late-fin air COoler%板翅式空气冷却器气动除霜的理论探析

    Institute of Scientific and Technical Information of China (English)

    毛业斌; 费千

    2001-01-01

    在气动除霜实验的基础之上,运用气体动力学理论、边界层理论,对气动除霜的机理进行了探析,指出当气流动力作用大于霜层与翅片的粘附功时,霜层被吹离翅片表面.%The method of pneumatic defrosting breaks through the traditional meaning of “melting”, and it is a newly developed defrosting method. In this paper, based on experiments and with the application of the theory on gas dynamics、 boundary-layer theory, the mechanism of pneumatic defrosting on plate-fin air cooler is studied theoretically. And it is pointed out that when the drive of airflow is greater than the adhesion work of frost, frost will be eliminated.

  18. Oleate lipase activity in Gardnerella vaginalis and reconsideration of existing biotype schemes

    Directory of Open Access Journals (Sweden)

    Moncla Bernard J

    2009-04-01

    Full Text Available Abstract Background Gardnerella vaginalis is a facultative gram positive organism that requires subculture every 1–2 days to maintain viability. It has been linked with bacterial vaginosis (BV, a syndrome that has been associated with increased risk for preterm delivery, pelvic inflammatory disease and HIV acquisition. About 10% of the G. vaginalis isolates have been reported to produce sialidase, but there have not been any studies relating sialidase production and biotype. Sialidase activity is dramatically increased in the vaginal fluid of women with BV and bacterial sialidases have been shown to increase the infectivity of HIV in vitro. There are 8 different biotypes of G. vaginalis. Biotypes 1–4 produce lipase and were reported to be associated with BV and the association of these biotypes with BV is under dispute. Other studies have demonstrated that G. vaginalis biotype 1 can stimulate HIV-1 production. Because of the discrepancies in the literature we compared the methods used to biotype G. vaginalis and investigated the relationship of biotype and sialidase production. Results A new medium for maintenance of Gardnerella vaginalis which allows survival for longer than one week is described. Some isolates only grew well under anaerobic conditions. Sialidase producing isolates were observed in 5 of the 6 biotypes tested. Using 4-methylumbelliferyl-oleate to determine lipase activity, instead of egg yolk agar, resulted in erroneous biotypes and does not provide reliable results. Conclusion Previous studies associating G. vaginalis biotype with bacterial vaginosis were methodologically flawed, suggesting there is not an association of G. vaginalis biotypes and bacterial vaginosis. Sialidase activity was observed in 5 of the 8 biotypes.

  19. Chaos suppression via observer based active control scheme: Application to Duffing's oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Lopez, Ricardo [Departamento de Energia, Universidad Autonoma Metropolita-Azcapotzalco, Av. San Pablo No. 180, Reynosa-Tamaulipas, Azcapotzalco 02200, Mexico DF (Mexico)]. E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, Rafael [Departamento de Control Automatico, CINVESTAV-IPN, C.P. 07360 Mexico DF (Mexico)

    2007-06-15

    The aim of this paper is the synthesis of a robust control law for chaos suppression of a class of non-linear oscillator with affine control input. A robust state observer based active controller, which provides robustness against model uncertainties and noisy output measurements is proposed. The closed-loop stability for the underlying closed-loop system is done via the regulation and estimation errors dynamics. The performance of the proposed control law is illustrated with numerical simulations. The method is general and can be applied to various non-linear systems which satisfy the conditions required.

  20. Optimization of the active absorber scheme for the protection of the Dispersion Suppressor

    CERN Document Server

    Magistris, M; Assmann, R; Bracco, C; Brugger, M; Cerutti, F; Ferrari, A; Redaelli, S; Vlachoudis, V

    2009-01-01

    There are two main types of cold elements in IR7: quadrupole and dipole magnets (MQ and MB). According to predictions, these objects are to lose their superconducting properties if the spurious power densities reach about 1 and 5 mW/cm3, respectively. In order to protect these fragile components, 5 active absorbers (TCLA) were designed and a systematic study was launched to maximize the shielding efficiency of the absorber system for different configurations (locations and orientations). The TCLA's are identical to the secondary collimators (TCS), the only difference is found in the material of the jaw, which, initially, was set integrally to Cu (instead of C) and later included a small W insertion. This report summarizes the survey of cold element protection through TCLA insertion optimization.

  1. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  2. GPU-based Monte Carlo Dust Radiative Transfer Scheme Applied to Active Galactic Nuclei

    Science.gov (United States)

    Heymann, Frank; Siebenmorgen, Ralf

    2012-05-01

    A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman & Wood method to reduce the calculation time, and the Fleck & Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 μm silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission.

  3. The Realization of a CO2 Heat Pump Defrosting Method%一种CO2热泵除霜方法的实现

    Institute of Scientific and Technical Information of China (English)

    杨军红

    2016-01-01

    空气源CO2热泵在冬季运行时,由于外部环境温度低、空气湿度大等原因,往往会在蒸发器表面形成霜层,从而降低热泵运行效率,甚至影响热泵机组的正常运行,根据CO2热泵的实际应用,设计一种CO2热泵智能除霜方法,用于解决空气源CO2热泵低温、高湿环境下的除霜问题。%Air source CO2 heat pump running in winter, due to the external environment of low temperature, high air humidity and so on, often formation frost layer in the evaporator surface, thereby reducing the efficiency of the heat pump, and even affect the normal operation of the heat pump units, this paper will according to the practical application of the CO2 heat pump, design a CO2 heat pump intelligent defrosting method, is used to solve the CO2 air source heat pump defrost problem under the low temperature, high humidity environment.

  4. Degradation in urban air quality from construction activity and increased traffic arising from a road widening scheme.

    Science.gov (United States)

    Font, Anna; Baker, Timothy; Mudway, Ian S; Purdie, Esme; Dunster, Christina; Fuller, Gary W

    2014-11-01

    Road widening schemes in urban areas are often proposed as a solution to traffic congestion and as a means of stimulating economic growth. There is however clear evidence that new or expanded roads rapidly fill with either displaced or induced traffic, offsetting any short-term gains in eased traffic flows. What has not been addressed in any great detail is the impact of such schemes on air quality, with modelled impact predictions seldom validated by measurements after the expansion of road capacity. In this study we made use of a road widening project in London to investigate the impact on ambient air quality (particulate matter, NOX, NO2) during and after the completion of the road works. PM10 increased during the construction period up to 15 μg m(-3) during working hours compared to concentrations before the road works. A box modelling approach was used to determine a median emission factor of 0.0022 kg PM10 m(-2) month(-1), three times larger than that used in the UK emission inventory (0.0007 kg PM10 m(-2) month(-1)). Peaks of activity released 0.0130 kg PM10 m(-2) month(-1), three and eight times smaller than the peak values used in the European and US inventories. After the completion of the widening there was an increase in all pollutants from the road during rush hour: 2-4 μg m(-3) for PM10; 1 μg m(-3) for PM2.5; 40 and 8 μg m(-3) for NOX and NO2, respectively. NO2 EU Limit Value was breached after the road development illustrating a notable deterioration in residential air quality. Additionally, PM10, but not PM2.5, glutathione dependent oxidative potential increased after the road was widened consistent with an increase in pro-oxidant components in the coarse particle mode, related to vehicle abrasion processes. These increased air pollution indices were associated with an increase in the number of cars, taxis and LGVs.

  5. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  6. Indirect Z-Scheme BiOI/g-C3N4 Photocatalysts with Enhanced Photoreduction CO2 Activity under Visible Light Irradiation.

    Science.gov (United States)

    Wang, Ji-Chao; Yao, Hong-Chang; Fan, Ze-Yu; Zhang, Lin; Wang, Jian-She; Zang, Shuang-Quan; Li, Zhong-Jun

    2016-02-17

    Rational design and construction of Z-scheme photocatalysts has received much attention in the field of CO2 reduction because of its great potential to solve the current energy and environmental crises. In this study, a series of Z-scheme BiOI/g-C3N4 photocatalysts are synthesized and their photocatalytic performance for CO2 reduction to produce CO, H2 and/or CH4 is evaluated under visible light irradiation (λ > 400 nm). The results show that the as-synthesized composites exhibit more highly efficient photocatalytic activity than pure g-C3N4 and BiOI and that the product yields change remarkably depending on the reaction conditions such as irradiation light wavelength. Emphasis is placed on identifying how the charge transfers across the heterojunctions and an indirect Z-scheme charge transfer mechanism is verified by detecting the intermediate I3(-) ions. The reaction mechanism is further proposed based on the detection of the intermediate (•)OH and H2O2. This work may be useful for rationally designing of new types of Z-scheme photocatalyst and provide some illuminating insights into the Z-scheme transfer mechanism.

  7. Research on Anodic Oxidation Preparation and Performance of Anti-icing Defrosting Coating%防冰除霜涂层的阳极氧化法制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    陈志; 闫共芹; 林瑞基; 闫斌; 刘建华

    2015-01-01

    输电线路覆冰使得电线出现一系列抖动、闪烁、烧伤现象,严重威胁着电力系统的安全运行,在输电线表面涂覆防冰除霜涂层制备防结冰除霜输电线是一种新的除冰防霜方法。为了探究防冰除霜涂层对输电线防冰除霜效果的影响,本文通过阳极氧化法制备出防冰除霜涂层输电线,并分别对不同材质的铝片进行实验研究。根据人工气候室中的实验结果,分析得出防冰除霜涂层对不同基底的输电线防冰都起到一定程度的作用,其中6061型号铝片延长结冰时间效果最好。%Transmission lines ice makes wire appearing a series of jitter, flicker, burned phenomenon. In transmission line surface coating anti-icing defrosting coating is a new method of deicing frost prevention.In order to explore the anti-icing defrosting coating on transmission line anti-icing defrosting effect, two different anti-icing defrosting coating were prepared by anode oxidation method on different aluminium materials. According to the experimental results of artificial climate chamber, two different deicing defrosting coating had inhibition to a certain degree in ice on power lines.Among them 6061 type aluminum prolonged freezing effect was best.

  8. MANIFESTATION OF THE EFFECT OF CRYOSELECTION IN CARP OFFSPRINGS OBTAINED FROM DEFROSTED SPERM SUSPENSION WITH MODIFIED CRYOPROTECTIVE SOLUTIONS

    Directory of Open Access Journals (Sweden)

    V. Cherepnin

    2016-09-01

    Full Text Available Purpose. The purpose of these studies was to evaluate the effect of the cryoselection of carp sperm of multiple age groups depending on the quality of thawed sperm after modification of the composite cryoprotective medium, which was used for the dilution of native sperm before freezing. Methodology. Coenzyme B12 (cobamamide, blood plasma of Prussian carp (Carassius gibelio, which was subjected to natural cold-acclimation, and purified protein antifreeze tmAFP isolated from larval mealworm (Tenebrio molitor, which also was subjected to natural cold-acclimation, were sued as modifiers. Findings. The results of the study demonstrated that qualitative and quantitative characteristics of the defrosted sperm, results of the incubation, rearing of embryos and larvae of Nyvky scaled carp (NLC, as well as fish culture parameters of produced young-of-the-year depended from on the composition of cryoprotective medium. The best results were demonstrated for the experimental groups, obtained with the use of the cryoprotective solution supplemented with purified antifreeze protein tmAFP. The larvae obtained from the sperm cryopreserved with the addition of cryoprotective medium TmAFP had better resistance to dehydration, surpassing the experimental groups obtained from the modifiers of Prussian carp plasma and cobamamide. There is a consolidation in the action of the related extracellular cryoprotectors, which were isolated from the cold-resistant organisms. And carp produced with their used demonstrated better performance during their rearing. The fact can be established that the manifestation of cryoselective effect depends on the integrity of sperm hereditary material and does not depend on the effect of extremely low temperatures on the cell membranes. Originality. There were the first experiments, where Prussian carp plasma and antifreeze protein tmAFP were used as extracellular cryoprotectors. Practical value. The modifications of composite

  9. Development and experiment about recombination heating circulation defrosting system of mini cold storage house%微型冷库复合加热循环除霜系统的研制与试验

    Institute of Scientific and Technical Information of China (English)

    赵松松; 杨昭; 陈爱强; 张娜; 陈明锋; 刘兴华

    2015-01-01

    针对冷冻冷藏库传统除霜方法高能耗、冷库温湿度波动大等缺陷,通过设计系统除霜结构,完善控制策略,研发了一种智能除霜方法。复合加热循环除霜采用时间—压差联合智能控制策略界定最佳除霜点,配备排管辅助制冷技术,基于欧姆龙PLC高精度控制系统使各设备协同完成除霜过程。对复合加热循环除霜系统进行试验研究,对比分析不同除霜方法的工作性能及能耗情况。结果显示:相比于传统电加热除霜,复合加热循环除霜过程冷库温度波动减小3.8℃,相对湿度波动降低21.1百分点,除霜时间缩短14 min,系统除霜节能率达34.5%。%In recent years, mini cold storage house has developed rapidly. The evaporator is extremely easy to frost as a result of locating in the condition of low temperature and high humidity. However, defrosting energy consumption accounts for more than 10% of system’s total energy consumption. To overcome the defect about high energy consumption, temperature and humidity fluctuation of traditional defrosting technology in mini cold storage house, we investigated a new framework by changing the structure of the defrosting system and optimizing the control technology. Firstly, we developed a new defrosting system named as recombination heating circulation defrosting (RHCD) based on overhead coil auxiliary refrigeration. After that, the time-differential pressure (TDP) combining intelligent control method was used innovatively to determine the best defrosting point. Finally, OMRON programmable logic controller was applied to combine some devices to finish the defrosting. In the defrosting process, the electric-air valves installed on the incubator were closed timely to restrain heat and vapor into the cold storage house, and hot air flow was forced to circulate in the bypass channel under the working of blowers. Meanwhile overhead coil auxiliary refrigeration system was

  10. Accounting for Students' Schemes in the Development of a Graphical Process for Solving Polynomial Inequalities in Instrumented Activity

    Science.gov (United States)

    Rivera, Ferdinand D.

    2007-01-01

    This paper provides an instrumental account of precalculus students' graphical process for solving polynomial inequalities. It is carried out in terms of the students' instrumental schemes as mediated by handheld graphing calculators and in cooperation with their classmates in a classroom setting. The ethnographic narrative relays an instrumental…

  11. Supporting Innovation Activities of SMEs with Innovation Vouchers Scheme%英国实施创新券计划支持中小企业创新

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      英国技术战略委员会(TSB)最新推出创新券计划(Innovation Vouchers Scheme),专门支持中小企业创新活动。作为英国政府推出新的创新资助工具之一,该计划资助对象明确、资助目标清晰,资助重点突出,并且在资助方式上跟以往科技计划比较有所创新。通过对TSB推出的创新券计划资助标准和原则、资助领域和重点以及申请和资助流程进行详细介绍和分析,简要总结出创新券计划的几个特点,以为我国有关科技计划和创新基金实施提供参考。%The Innovation Vouchers Scheme was launched by Technology Strategy Board (TSB) of UK in 2012 as a new funding tool to support the innovation activities of SMEs specifically. The objects and priorities of Innovation Vouchers Scheme are clearly defined and the funding mode of the scheme has a big difference from other S&T programs. This paper introduced the funding standards and principles of the scheme, analyzed its funding priorities and application procedure, and summarized the new characteristics of Innovation Vouchers Scheme, hoping to provide a useful reference for the policy making and implement of innovation plan and programs in China.

  12. New Driving Scheme to Improve Hysteresis Characteristics of Organic Thin Film Transistor-Driven Active-Matrix Organic Light Emitting Diode Display

    Science.gov (United States)

    Yamamoto, Toshihiro; Nakajima, Yoshiki; Takei, Tatsuya; Fujisaki, Yoshihide; Fukagawa, Hirohiko; Suzuki, Mitsunori; Motomura, Genichi; Sato, Hiroto; Tokito, Shizuo; Fujikake, Hideo

    2011-02-01

    A new driving scheme for an active-matrix organic light emitting diode (AMOLED) display was developed to prevent the picture quality degradation caused by the hysteresis characteristics of organic thin film transistors (OTFTs). In this driving scheme, the gate electrode voltage of a driving-OTFT is directly controlled through the storage capacitor so that the operating point for the driving-OTFT is on the same hysteresis curve for every pixel after signal data are stored in the storage capacitor. Although the number of OTFTs in each pixel for the AMOLED display is restricted because OTFT size should be large enough to drive organic light emitting diodes (OLEDs) due to their small carrier mobility, it can improve the picture quality for an OTFT-driven flexible OLED display with the basic two transistor-one capacitor circuitry.

  13. 制冷剂流量控制法在风冷热泵除霜中的应用%Application of Refrigerant Flux Control Method in Air-cooled Heat Pump Defrosting

    Institute of Scientific and Technical Information of China (English)

    苏顺玉; 田甜; 陈俭

    2011-01-01

    Based on the difference of refrigerant flux between refrigeration operating condition and heating operating condition in a heat-pump air-conditioning system, the refrigerant flux in the heat-pump air-conditioning system was controlled by refrigerant flux control method. And the combined method with refrigerant flux control and hot gas bypass defrosting was applied in heat-pump defrosting. The results show that the heat-pump air-conditioning cycling system with refrigerant flux control can be used to restrain or retard frosting in the surface of outdoor heat-exchanger while this system works in order. When the surface of outdoor heat-exchanger was already covered with frost, this system could be used to accelerate defrosting or shorten defrosting time.%根据热泵空调系统中制冷工况和制热工况时制冷剂流量的差别,采用制冷剂流量控制法对热泵空调系统中的制冷剂流量进行控制,并将制冷剂流量控制法与热气旁通法除霜相结合应用于热泵除霜过程中。结果表明,在控制制冷剂流量的热泵空调系统中,系统正常运行时,该循环系统能抑制或减缓室外换热器表面的结霜;当室外换热器表面结霜时,则可加速除霜,缩短除霜时间。

  14. Fabrication and photocatalytic activity enhanced mechanism of direct Z-scheme g-C3N4/Ag2WO4 photocatalyst

    Science.gov (United States)

    Zhu, Bicheng; Xia, Pengfei; Li, Yao; Ho, Wingkei; Yu, Jiaguo

    2017-01-01

    Herein, a direct Z-scheme graphitic carbon nitride (g-C3N4)/silver tungstate (Ag2WO4) photocatalyst was prepared by a facile in situ precipitation method using g-C3N4 as a support and silver nitrate as a precursor. X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental mapping demonstrated that β-Ag2WO4 nanoparticles were evenly distributed on the surface of g-C3N4 nanosheets, which acted as a support for the nucleation and growth of β-Ag2WO4 and inhibited the phase transformation of metastable β-Ag2WO4 to stable α-Ag2WO4. Photocatalytic experiments indicated that the g-C3N4/Ag2WO4 nanocomposite photocatalyst displayed a better photocatalytic activity than pure g-C3N4 and Ag2WO4 toward the degradation of methyl orange. The enhanced photocatalytic performance of g-C3N4/Ag2WO4 could be well explained by a direct Z-scheme photocatalytic mechanism. This mechanism was related to the efficient space separation of photogenerated electron-hole pairs and the great oxidation and reduction capabilities of the g-C3N4/Ag2WO4 system. This work provided new insights into the design and fabrication of g-C3N4-based direct Z-scheme photocatalysts.

  15. Constructing probabilistic models for realistic velocity distributions based on forward modeling and tomographic inversion: applications for active and passive source observation schemes

    Science.gov (United States)

    Koulakov, I. Yu.

    2009-04-01

    Seismic tomography is like a photography taken by a camera with deformed and blurred lenses. In the resulting tomograms, colors (amplitudes of anomalies) and shapes of objects are often strongly biased and are usually not representing the reality. We propose an approach which allows investigating properties of the "camera" and retrieving most probable shapes and amplitudes of anomalies in the real Earth. The main idea of this approach is to construct a synthetic model which, after performing forward modeling and tomographic inversion, reproduces the same amplitudes and shapes of patterns as after inversion of observed data. In this modeling, the conditions of the tomographic inversion (damping, grid spacing, source location parameters etc) should be absolutely identical to the case of the observed data processing. The a priori information, if available any, should be taken into account in this modeling to decrease the uncertainty related to fundamental non-uniqueness of the inversion problem. In the talk, several examples of applying this approach at various scales for different data schemes are presented: (1) regional scheme which uses the global data of the ISC catalogue (with examples of regional upper mantle models in Europe and central Asia); (2) local earthquake tomography scheme (illustrated with models in Toba caldera area and in Central Java); (3) seismic profiling which is based on active source refraction travel time data (with examples of several deep seismic sounding profiles in Central Pacific and subduction zones in Chile).

  16. Fabrication of Z-scheme Ag3PO4/MoS2 composites with enhanced photocatalytic activity and stability for organic pollutant degradation

    Science.gov (United States)

    Zhu, Chaosheng; Zhang, Lu; Jiang, Bo; Zheng, Jingtang; Hu, Ping; Li, Sujuan; Wu, Mingbo; Wu, Wenting

    2016-07-01

    In this study, highly efficient visible-light-driven Ag3PO4/MoS2 composite photocatalysts with different weight ratios of MoS2 were prepared via the ethanol-water mixed solvents precipitation method and characterized by ICP, XRD, HRTEM, FE-SEM, BET, XPS, UV-vis DRS and PL analysis. Under visible-light irradiation, Ag3PO4/MoS2 composites exhibit excellent photocatalytic activity towards the degradation of organic pollutants in aqueous solution. The optimal composite with 0.648 wt% MoS2 content exhibits the highest photocatalytic activity, which can degrade almost all MB under visible-light irradiation within 60 min. Recycling experiments confirmed that the Ag3PO4/MoS2 catalysts had superior cycle performance and stability. The photocatalytic activity enhancement of Ag3PO4/MoS2 photocatalysts can be mainly ascribed to the efficient separation of photogenerated charge carriers and the stronger oxidation and reduction ability through a Z-scheme system composed of Ag3PO4, Ag and MoS2, in which Ag particles act as the charge separation center. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Ag3PO4 by transferring the photogenerated electrons of Ag3PO4 to MoS2. The evidence of the Z-scheme photocatalytic mechanism of the composite photocatalysts could be obtained from the active species trapping experiments and the photoluminescence technique.

  17. Rational construction of Z-scheme Ag2CrO4/g-C3N4 composites with enhanced visible-light photocatalytic activity

    Science.gov (United States)

    Luo, Jin; Zhou, Xiaosong; Ma, Lin; Xu, Xuyao

    2016-12-01

    Novel visible-light driven Z-scheme Ag2CrO4/g-C3N4 composites with different contents of Ag2CrO4 were fabricated by a facile chemical precipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy and photoelectrochemical measurements. Compared with individual g-C3N4 and Ag2CrO4, the Ag2CrO4/g-C3N4 composites displayed much larger photocatalytic activities for the photocatalytic degradation of methyl orange (MO) solution at room temperature under visible light irradiation (λ > 420 nm). Importantly, the optimum photodegradation rate constant of the Ag2CrO4/g-C3N4 composite at a theoretical weight content of 8.0% Ag2CrO4 for the photodegradation of MO was 0.0068 min-1, which was 5.7 and 4.3 times higher than that of pure g-C3N4 and Ag2CrO4, respectively. Such enormous enhancement in photocatalytic performance was predominantly ascribed to the efficient separation and transfer of photogenerated electrons and holes at the Ag2CrO4/g-C3N4 interface imparted through the Z-scheme electron transfer. Furthermore, radical trap experiments depicted that both the holes and superoxide radical anions were thought to dominate oxidative species of the Ag2CrO4/g-C3N4 composite for MO degradation under visible light irradiation. Ultimately, a tentative Z-scheme photodegradation mechanism was proposed. This work may be useful for the rational design of new types of Z-scheme photocatalysts and provide some illuminate insights into the Z-scheme transfer mechanism for application in energy conversion and environmental remediation.

  18. In-situ preparation of Z-scheme AgI/Bi5O7I hybrid and its excellent photocatalytic activity

    Science.gov (United States)

    Cui, Min; Yu, Jingxiong; Lin, Hongjun; Wu, Ying; Zhao, Leihong; He, Yiming

    2016-11-01

    The aim of this work was to synthesize, characterize and evaluate the photocatalytic activity of AgI/Bi5O7I composite photocatalyst under visible light irradiation. The photocatalyst was prepared by a simple one-step ionic reaction between Bi5O7I microrods and AgNO3 solutions, and was characterized by various techniques including X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The characterizations indicate that AgI particles were closely anchored on Bi5O7I micronods. During the photocataytic reaction, the composite was actually an Ag-AgI-Bi5O7I ternary system. The plasmonic effect of the formed Ag nanoparticles improved the visible light absorption performance, which benefits the photocatalytic reaction. However, more important was the formed heterojunction structure in the composite, which efficiently promoted the separation of electron-hole pairs by a plasmonic Z-scheme mechanism, and ultimately enhanced the photocatalytic activity. The optimal AgI/Bi5O7I composite showed a RhB degradation rate of 0.046 min-1, which was 3.83 and 6.57 times higher than those of Bi5O7I and AgI, respectively. This work may provide some insight into the design of novel and highly efficient Z-scheme visible-light photocatalysts.

  19. Efficient active feedback scheme of image multi-class classification%结合主动反馈的图像多分类框架

    Institute of Scientific and Technical Information of China (English)

    刘君; 王银辉; 李黎; 张宇

    2011-01-01

    为了解决图像语义分类中的训练数据不对称、小样本训练和噪声数据这3个难题,提出结合主动反馈的图像多分类框架.该框架将主动选择的策略应用到图像的多分类中,通过主动的选择出不确定的图片给用户手动标记,扩大训练图片集,提高分类的精度.为了验证该框架的有效性,提出一种有效的结合主动选择的图像多分类算法,即结合投票的DDAG SVM(decision directed acyclic graph support vector machine)算法.该算法提出了新的主动选择策略,即结合投票和旁移机制的主动选择策略.实验结果表明,该算法能有效应用到图像多分类中,比DDAGSVM和采用普通主动选择策略的DDAGSVM具有更高的分类的精度.%In order to solve three difficulties of image classification, including asymmetry of training data, small sample issue and noise sample problem, efficient active feedback scheme of image multi-class classification which introduce active selecting technique into image multi-class classification is proposed. By actively selecting doubtful images for users to label, more training samples can be gotten and more accurate classification can be done. In order to validate the scheme, an image multi-class classification algorithm combining with active selecting is fulfilled, which is named as DDAG SVM (decision directed acyclic graph support vector machine) with voting.Experiments show that the algorithm has more accuracy than DDAG SVM and DDAG SVM with normal selecting strategy, so it is efficient and the proposed scheme is also good for image multi-class classification.

  20. Laterotrusive occlusal schemes and jaw posture tasks effects on supra- and infrahyoid EMG activity in the lateral decubitus position.

    Science.gov (United States)

    Miralles, Rodolfo; Gallardo, Francisca; Baeza, Mauricio; Valenzuela, Saúl; Ravera, María José; Ormeño, Guillermo; Cavada, Gabriel

    2007-04-01

    The purpose of this study was to determine the effect of canine guidance and group function on supra- and infrahyoid EMG activity in the lateral decubitus position at different jaw posture tasks. The sample included 40 healthy subjects with natural dentition and bilateral molar support, 20 with bilateral canine guidance and 20 with bilateral group function. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left supra- and infrahyoid muscles for EMG recordings. In the lateral decubitus position, EMG activity was recorded in subjects with canine guidance or group function, during the following jaw posture tasks: A. maximal clenching in the edge-to edge lateral contact position; B. grinding from intercuspal position to edge-to-edge lateral contact position, and C. grinding from edge-to-edge lateral contact position to intercuspal position. Supra- and infrahyoid EMG activity was not significantly different with canine guidance or group function (mixed model with unstructured covariance matrix). Overall comparison of suprahyoid or infrahyoid EMG activity among the three jaw posture tasks studied showed a significantly higher activity during jaw posture task A (clenching) than jaw posture tasks B and C (grinding). Suprahyoid EMG activity was significantly higher during jaw posture task C than B, whereas infrahyoid EMG activity did not present a significant difference between jaw posture tasks C and B. These EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding. The neurophysiological mechanisms involved are discussed.

  1. News Schemes for Activity Recognition Systems Using PCA-WSVM, ICA-WSVM, and LDA-WSVM

    Directory of Open Access Journals (Sweden)

    M’hamed Bilal Abidine

    2015-08-01

    Full Text Available Feature extraction and classification are two key steps for activity recognition in a smart home environment. In this work, we used three methods for feature extraction: Principal Component Analysis (PCA, Independent Component Analysis (ICA, and Linear Discriminant Analysis (LDA. The new features selected by each method are then used as the inputs for a Weighted Support Vector Machines (WSVM classifier. This classifier is used to handle the problem of imbalanced activity data from the sensor readings. The experiments were implemented on multiple real-world datasets with Conditional Random Fields (CRF, standard Support Vector Machines (SVM, Weighted SVM, and combined methods PCA+WSVM, ICA+WSVM, and LDA+WSVM showed that LDA+WSVM had a higher recognition rate than other methods for activity recognition.

  2. Electromyographic activity of hand muscles in a motor coordination game: effect of incentive scheme and its relation with social capital.

    Directory of Open Access Journals (Sweden)

    Roberto Censolo

    Full Text Available BACKGROUND: A vast body of social and cognitive psychology studies in humans reports evidence that external rewards, typically monetary ones, undermine intrinsic motivation. These findings challenge the standard selfish-rationality assumption at the core of economic reasoning. In the present work we aimed at investigating whether the different modulation of a given monetary reward automatically and unconsciously affects effort and performance of participants involved in a game devoid of visual and verbal interaction and without any perspective-taking activity. METHODOLOGY/PRINCIPAL FINDINGS: Twelve pairs of participants were submitted to a simple motor coordination game while recording the electromyographic activity of First Dorsal Interosseus (FDI, the muscle mainly involved in the task. EMG data show a clear effect of alternative rewards strategies on subjects' motor behavior. Moreover, participants' stock of relevant past social experiences, measured by a specifically designed questionnaire, was significantly correlated with EMG activity, showing that only low social capital subjects responded to monetary incentives consistently with a standard rationality prediction. CONCLUSIONS/SIGNIFICANCE: Our findings show that the effect of extrinsic motivations on performance may arise outside social contexts involving complex cognitive processes due to conscious perspective-taking activity. More importantly, the peculiar performance of low social capital individuals, in agreement with standard economic reasoning, adds to the knowledge of the circumstances that makes the crowding out/in of intrinsic motivation likely to occur. This may help in improving the prediction and accuracy of economic models and reconcile this puzzling effect of external incentives with economic theory.

  3. Optimization of Vehicle Defrosting Performance Based on Program Integration and Response Surface Model%基于程序集成及响应面模型的车辆除霜性能优化

    Institute of Scientific and Technical Information of China (English)

    张炳力; 胡忠文; 薛铁龙

    2015-01-01

    A three-dimensional simulation model for the defrosting performance of a car is created. With the grill angles of air duct outlet are selected as experimental factors and the heating air speed on windshield sur-face as objective function, and by using program integration to make Isight as upper layer software and integrating automatic mesh deformation software Sculptor with CFD software Star-ccm+, the sample data are obtained by auto-matic submission for calculation. The Latin hypercube design and the least square method are used to create a sec-ond-order response surface model for the heating air speed on windshield surface, and a parameter optimization is conducted with mixed-integer optimization algorithm. After optimization, the distribution of heating air speed on windshield surface is obviously improved and the results of transient simulation on defrosting show that the defros-ting speed is increased, meeting the requirements of national standard on the defrosting performance of vehicle windshield.%建立了某款轿车除霜仿真三维模型。选择风道出口格栅角度为试验因子,风窗玻璃表面风速为目标函数,使用程序集成的方法,将Isight作为上层软件,集成自动网格变形软件Sculptor和CFD计算软件Star-ccm+,自动提交运算得到样本数据。采用拉丁超立方设计方法和最小二乘法,创建了汽车风窗玻璃表面暖风风速的二阶响应面模型,利用混合整型优化法进行参数优化。优化后,汽车前风窗玻璃表面的除霜暖风流速分布有了明显的改善,除霜瞬态仿真结果表明,除霜速度加快,满足了国标关于汽车风窗玻璃除霜性能的要求。

  4. Generalized Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The concept of generalized group signature scheme will bepresent. Based on the generalized secret sharing scheme proposed by Lin and Ha rn, a non-interactive approach is designed for realizing such generalized group signature scheme. Using the new scheme, the authorized subsets of the group in w hich the group member can cooperate to produce the valid signature for any messa ge can be randomly specified

  5. Enhanced visible light activity on direct contact Z-scheme g-C3N4-TiO2 photocatalyst

    Science.gov (United States)

    Li, Juan; Zhang, Min; Li, Qiuye; Yang, Jianjun

    2017-01-01

    Direct contact Z-scheme g-C3N4-TiO2 nanocomposites without an electron mediator are prepared via simple annealing the mixture of bulk g-C3N4 and nanotube titanic acid (NTA) in air at 600 °C for 2 h. In the process of annealing, the bulk g-C3N4 transformed to ultra-thin g-C3N4 nanosheets, and NTA converted to a novel anatase TiO2, then the two components formed a close interaction. The XPS result reveals that some amount of nitrogen is doped into this novel-TiO2, and g-C3N4 nanosheets exist in the composites. The results of XRD, TEM and TG indicate that the thickness of g-C3N4 nanosheets is very thin. The ESR spectrum shows the existence of Ti3+ and single-electron-trapped oxygen vacancy in the 30%g-C3N4-TiO2 composites. In photocatalytic activity test, the 30%g-C3N4-TiO2 nanocomposites showed an excellent photo-oxidation activity of propylene under visible light irradiation (λ≥ 420 nm), and the removal efficiency of propylene reached as high as 56.6%, and the activity kept nearly 82% after four consecutive recycles. Photoluminescence (PL) result using terephthalic acid (TA) as a probe molecule indicated that the g-C3N4-TiO2 nanocomposites displayed a Z-sheme photocatalytic reaction system and this should be the main reason for the high photocatalytic activity. A possible photocatalytic mechanism was proposed on the basis of PL result and transient photocurrent-time curves.

  6. Pixel-Level Digital-to-Analog Conversion Scheme with Compensation of Thin-Film-Transistor Variations for Compact Integrated Data Drivers of Active Matrix Organic Light Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Park, Sang-Gyu; Choi, Byong-Deok

    2011-03-01

    The previous pixel-level digital-to-analog-conversion (DAC) scheme that implements a part of a DAC in a pixel circuit turned out to be very efficient for reducing the peripheral area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). However, how the pixel-level DAC can be compatible with the existing pixel circuits including compensation schemes of TFT variations and IR drops on supply rails, which is of primary importance for active matrix organic light emitting diodes (AMOLEDs) is an issue in this scheme, because LTPS TFTs suffer from random variations in their characteristics. In this paper, we show that the pixel-level DAC scheme can be successfully used with the previous compensation schemes by giving two examples of voltage- and current-programming pixels. The previous pixel-level DAC schemes require additional two TFTs and one capacitor, but for these newly proposed pixel circuits, the overhead is no more than two TFTs by utilizing the already existing capacitor. In addition, through a detailed analysis, it has been shown that the pixel-level DAC can be expanded to a 4-bit resolution, or be applied together with 1:2 demultiplexing driving for 6- to 8-in. diagonal XGA AMOLED display panels.

  7. MIDI Programming in Scheme

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2010-01-01

    A Scheme representation of Standard MIDI Files is proposed. The Scheme expressions are defined and constrained by an XML-language, which in the starting point is inspired by a MIDI XML event language made by the MIDI Manufactures Association. The representation of Standard MIDI Files in Scheme ma...

  8. Scheme Program Documentation Tools

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2004-01-01

    This paper describes and discusses two different Scheme documentation tools. The first is SchemeDoc, which is intended for documentation of the interfaces of Scheme libraries (APIs). The second is the Scheme Elucidator, which is for internal documentation of Scheme programs. Although the tools...... are separate and intended for different documentation purposes they are related to each other in several ways. Both tools are based on XML languages for tool setup and for documentation authoring. In addition, both tools rely on the LAML framework which---in a systematic way---makes an XML language available...

  9. Electrical injection schemes for nanolasers

    DEFF Research Database (Denmark)

    Lupi, Alexandra; Chung, Il-Sug; Yvind, Kresten

    2013-01-01

    The performance of injection schemes among recently demonstrated electrically pumped photonic crystal nanolasers has been investigated numerically. The computation has been carried out at room temperature using a commercial semiconductor simulation software. For the simulations two electrical...... injection schemes have been compared: vertical pi- n junction through a current post structure as in1 and lateral p-i-n junction with either uniform material as in2 or with a buried heterostructure (BH) as in3. To allow a direct comparison of the three schemes the same active material composition consisting...... of 3 InGaAsP QWs on an InP substrate has been chosen for the modeling. In the simulations the main focus is on the electrical and optical properties of the nanolasers i.e. electrical resistance, threshold voltage, threshold current and wallplug efficiency. In the current flow evaluation the lowest...

  10. Convertible Proxy Signcryption Scheme

    Institute of Scientific and Technical Information of China (English)

    李继国; 李建中; 曹珍富; 张亦辰

    2004-01-01

    In 1996, Mambo et al introduced the concept of proxy signature. However, proxy signature can only provide the delegated authenticity and cannot provide confidentiality. Recently, Gamage et al and Chan and Wei proposed different proxy signcryption schemes respectively, which extended the concept of proxy signature.However, only the specified receiver can decrypt and verify the validity of proxy signcryption in their schemes.To protect the receiver' s benefit in case of a later dispute, Wu and Hsu proposed a convertible authenticated encryption scheme, which carn enable the receiver to convert signature into an ordinary one that can be verified by anyone. Based on Wu and Hsu' s scheme and improved Kim' s scheme, we propose a convertible proxy signcryption scheme. The security of the proposed scheme is based on the intractability of reversing the one-way hash function and solving the discrete logarithm problem. The proposed scheme can satisfy all properties of strong proxy signature and withstand the public key substitution attack and does not use secure channel. In addition, the proposed scheme can be extended to convertible threshold proxy signcryption scheme.

  11. Efficient Threshold Signature Scheme

    Directory of Open Access Journals (Sweden)

    Sattar J Aboud

    2012-01-01

    Full Text Available In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing process of the proposed scheme is more efficient in terms of time complexity and interaction.

  12. Stateless Transitive Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    MA Chun-guang; CAI Man-chun; YANG Yi-xian

    2004-01-01

    A new practical method is introduced to transform the stateful transitive signature scheme to stateless one without the loss of security. According to the approach, two concrete stateless transitive signature schemes based on Factoring and RSA are presented respectively. Under the assumption of the hardness of factoring and one-more- RSA-inversion problem, both two schemes are secure under the adaptive chosen-message attacks in random oracle model.

  13. Incorporating an advanced aerosol activation parameterization into WRF-CAM5: Model evaluation and parameterization intercomparison: An Advanced Aerosol Activation Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yang [Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh North Carolina USA; Collaborative Innovation Center for Regional Environmental Quality, Beijing China; Zhang, Xin [Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh North Carolina USA; Wang, Kai [Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh North Carolina USA; He, Jian [Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh North Carolina USA; Leung, L. Ruby [Pacific Northwest National Laboratory, Richland Washington USA; Fan, Jiwen [Pacific Northwest National Laboratory, Richland Washington USA; Nenes, Athanasios [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia USA

    2015-07-22

    Aerosol activation into cloud droplets is an important process that governs aerosol indirect effects. The advanced treatment of aerosol activation by Fountoukis and Nenes (2005) and its recent updates, collectively called the FN series, have been incorporated into a newly developed regional coupled climate-air quality model based on the Weather Research and Forecasting model with the physics package of the Community Atmosphere Model version 5 (WRF-CAM5) to simulate aerosol-cloud interactions in both resolved and convective clouds. The model is applied to East Asia for two full years of 2005 and 2010. A comprehensive model evaluation is performed for model predictions of meteorological, radiative, and cloud variables, chemical concentrations, and column mass abundances against satellite data and surface observations from air quality monitoring sites across East Asia. The model performs overall well for major meteorological variables including near-surface temperature, specific humidity, wind speed, precipitation, cloud fraction, precipitable water, downward shortwave and longwave radiation, and column mass abundances of CO, SO2, NO2, HCHO, and O3 in terms of both magnitudes and spatial distributions. Larger biases exist in the predictions of surface concentrations of CO and NOx at all sites and SO2, O3, PM2.5, and PM10 concentrations at some sites, aerosol optical depth, cloud condensation nuclei over ocean, cloud droplet number concentration (CDNC), cloud liquid and ice water path, and cloud optical thickness. Compared with the default Abdul-Razzack Ghan (2000) parameterization, simulations with the FN series produce ~107–113% higher CDNC, with half of the difference attributable to the higher aerosol activation fraction by the FN series and the remaining half due to feedbacks in subsequent cloud microphysical processes. With the higher CDNC, the FN series are more skillful in simulating cloud water path, cloud optical thickness, downward shortwave radiation

  14. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    Goutsias, J.; Heijmans, H.J.A.M.

    1998-01-01

    [PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis and synthes

  15. Monitoring of the ground surface temperature and the active layer in NorthEastern Canadian permafrost areas using remote sensing data assimilated in a climate land surface scheme.

    Science.gov (United States)

    Marchand, N.; Royer, A.; Krinner, G.; Roy, A.

    2014-12-01

    Projected future warming is particularly strong in the Northern high latitudes where increases of temperatures are up to 2 to 6 °C. Permafrost is present on 25 % of the northern hemisphere lands and contain high quantities of « frozen » carbon, estimated at 1400 Gt (40 % of the global terrestrial carbon). The aim of this study is to improve our understanding of the climate evolution in arctic areas, and more specifically of land areas covered by snow. The objective is to describe the ground temperature year round including under snow cover, and to analyse the active layer thickness evolution in relation to the climate variability. We use satellite data (fusion of MODIS land surface temperature « LST » and microwave AMSR-E brightness temperature « Tb ») assimilated in the Canadian Land Surface Scheme (CLASS) of the Canadian climate model coupled with a simple radiative transfer model (HUT). This approach benefits from the advantages of each of the data type in order to complete two objectives : 1- build a solid methodology for retrieving the ground temperature, with and without snow cover, in taïga and tundra areas ; 2 - from those retrieved ground temperatures, derive the summer melt duration and the active layer depth. We describe the coupling of the models and the methodology that adjusts the meteorological input parameters of the CLASS model (mainly air temperature and precipitations derived from the NARR database) in order to minimise the simulated LST and Tb ouputs in comparison with satellite measurements. Using ground-based meteorological data as validation references in NorthEastern Canadian tundra, the results show that the proposed approach improves the soil temperatures estimates when using the MODIS LST and Tb at 10 and 19 GHz to constrain the model in comparison with the model outputs without satellite data. Error analysis is discussed for the summer period (2.5 - 4 K) and for the snow covered winter period (2 - 3.5 K). Further steps are

  16. AUTISTIC CHILDREN PROTECTION SCHEME

    Directory of Open Access Journals (Sweden)

    Dragan LUKIC

    1998-09-01

    Full Text Available The present article sets forth the theoretical grounds which make the basis for the organizational scheme of the autistic persons social protection. This protection consists of the below listed forms of work:· Health service with the role of an early detection and participation in the creation of rehabilitation programs;· Social protection with its programs of work from the diagnostics where the defectologist makes a team together with the physician and the psychologists to the systems of rehabilitation institutions where the defectologist’s is the main responsibility.The present article underlines two facts, namely:· that an autistic person requires to be followed and every spare moment used to promote and advance the activities the doer commenced himself instead of having him carry out the programs which are beyond his internal motivations and which he finds emotionally inaccessible;· that and form of work organization with autistic persons must subordinate its administrative part to the basic professional requirements this kind of disorder (handicap sets in front of each professional.

  17. Protection Scheme for Active Distribution System Based on Multi-agent Technology%基于多Agent技术的主动配电网保护方案

    Institute of Scientific and Technical Information of China (English)

    文亮; 陈众; 廖九林

    2016-01-01

    After distributed power ( DG) access to distribution network, which changes the structure of power dis⁃tribution network and leads to mis⁃operation and malfunction of protective relays. A multi⁃agent protective relay is proposed for active distribution grid based on fault current information. The scheme adopts the triple agent control structure, the underlying agency responsible for information collection, policy agency responsible for fault location;the top responsible for the entire network state monitoring. Through analyzing the characteristics of the multiple branch node current fault component phase angle and the mutation direction of the fault before and after the current phase angle on both ends of the line, put forward two kinds of decision making units fault judgement matrix algo⁃rithm. The method used the wide⁃area fault information can not only provide the main protection but also backup protection for adjacent lines and equipment. The simulation results show that the proposed method is correct and feasible.%分布式电源( DG)接入配电网后,改变了配电网网络结构,导致原有保护装置出现拒动和误动等问题。提出了一种针对主动配电网且根据故障电流信号的多Agent保护方案。该方案采用三级代理的控制结构,底层代理负责信息采集,决策层代理负责故障定位,顶层负责全网状态监控。通过分析多分支节点电流故障分量相角特点和线路两端故障前后电流相角的突变方向,提出了两类决策单元的故障判定矩阵算法。该方法运用了广域故障信息,不仅能够提供主保护,还能为相邻线路和设备提供后备保护。最后,通过仿真分析结果证明该方法的正确性和可行性。

  18. A Fuzzy Commitment Scheme

    CERN Document Server

    Al-saggaf, Alawi A

    2008-01-01

    This paper attempt has been made to explain a fuzzy commitment scheme. In the conventional Commitment schemes, both committed string m and valid opening key are required to enable the sender to prove the commitment. However there could be many instances where the transmission involves noise or minor errors arising purely because of the factors over which neither the sender nor the receiver have any control. The fuzzy commitment scheme presented in this paper is to accept the opening key that is close to the original one in suitable distance metric, but not necessarily identical. The concept itself is illustrated with the help of simple situation.

  19. Can adding web-based support to UK primary care exercise referral schemes improve patients’ physical activity levels? Findings from an internal pilot study.

    Directory of Open Access Journals (Sweden)

    Adrian Taylor

    2015-10-01

    Full Text Available Background: Promoting physical activity (PA via primary care exercise referral schemes (ERS is common but there is no rigorous evidence for long term changes in PA (Pavey et al, 2011 among those with chronic conditions. From July 2015, for 15 months, the e-coachER trial began to recruit 1400 patients (in SW England, Birmingham and Glasgow with one or more chronic conditions including diabetes, obesity, hypertension, osteoarthritis, or depression, who are eligible and about to attend an ERS. The two-arm parallel RCT is powered to determine if the addition of a web-based, interactive, theory-driven and evidence-based support system called e-coachER (hosted on the ‘LifeGuide’ platform will result in at least 10% more patients who do 150 mins or more per week of accelerometer assessed moderate or vigorous physical activity (MVPA at 12 months. Recruitment into the trial is within primary care, using both mail-merged patient invitations and opportunistic GP invitations (and exercise referrals. Within the trial, after participants are screened, provide consent and complete baseline assessments, they are randomised to receive usual ERS at each site or usual ERS plus a mailed Welcome Pack with registration details to access e-coachER on-line. Inclusion criteria for entering the trial are: (1 Aged 16-74 years; (2 with one or more of the following: obesity (BMI 30-35, hypertension (SBP 140-179 or DBP 90-109, type 2 diabetes, lower limb osteoarthritis, recent history of treatment for depression; (3 Participants who are in the two lowest (of four groups using the GP Physical Activity Questionnaire; (4 have an e-mail address and access to the internet; (5 Eligible for an ERS. The intervention rationale, design and content are reported in another presentation. Aims: This presentation will provide initial findings from a 3 month internal pilot phase with a focus on trial recruitment and initial intervention engagement. We will present data on the

  20. CSR schemes in agribusiness

    DEFF Research Database (Denmark)

    Pötz, Katharina Anna; Haas, Rainer; Balzarova, Michaela

    2013-01-01

    Purpose – The rise of CSR followed a demand for CSR standards and guidelines. In a sector already characterized by a large number of standards, the authors seek to ask what CSR schemes apply to agribusiness, and how they can be systematically compared and analysed. Design....../methodology/approach – Following a deductive-inductive approach the authors develop a model to compare and analyse CSR schemes based on existing studies and on coding qualitative data on 216 CSR schemes. Findings – The authors confirm that CSR standards and guidelines have entered agribusiness and identify a complex landscape...... of schemes that can be categorized on focus areas, scales, mechanisms, origins, types and commitment levels. Research limitations/implications – The findings contribute to conceptual and empirical research on existing models to compare and analyse CSR standards. Sampling technique and depth of analysis limit...

  1. Secure Order-Specified Multisignature Scheme Based on DSA

    Institute of Scientific and Technical Information of China (English)

    YANG Muxiang; SU Li; LI Jun; HONG Fan

    2006-01-01

    In multisignature schemes signers can sign either in a linear order or not in any specified order, but neither of them is adequate in some scenarios where require mixture using of orderless and ordered multisignature. Most order-specified multisignatures specified the orders as linear ones. In this paper, we proposed an order-specified multisignature scheme based on DSA secure against active insider attack. To our knowledge, it is the first order-specified multisignature scheme based on DSA signature scheme, in which signers can sign in flexible order represented by series-parallel graphs. In the multisignature scheme verification to both signers and signing order are available. The security of the scheme is proved by reduce to an identification scheme that is proved have some concrete security. The running time of verifying a signature is comparable to previous schemes while the running time of multisignature generation and the space needed is less than those schemes.

  2. XTR-Kurosawa-Desmedt Scheme

    Institute of Scientific and Technical Information of China (English)

    DING XIU-HUAN; FU ZHI-GUO; ZHANG SHU-GONG

    2009-01-01

    This paper proposes an XTR version of the Kurosawa-Desmedt scheme. Our scheme is secure against adaptive choeen-ciphertext attack under the XTR version of the Decisional Diffie-Hellman assumption in the standard model. Comparing efficiency between the Kurosawa-Desmedt scheme and the proposed XTR-Kurosawa-Desmedt scheme, we find that the proposed scheme is more efficient than the Kurosawa-Desmedt scheme both in communication and computation without compromising security.

  3. Succesful labelling schemes

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2001-01-01

    It is usual practice to evaluate the success of a labelling scheme by looking at the awareness percentage, but in many cases this is not sufficient. The awareness percentage gives no indication of which of the consumer segments that are aware of and use labelling schemes and which do not. In the ......It is usual practice to evaluate the success of a labelling scheme by looking at the awareness percentage, but in many cases this is not sufficient. The awareness percentage gives no indication of which of the consumer segments that are aware of and use labelling schemes and which do not....... In the spring of 2001 MAPP carried out an extensive consumer study with special emphasis on the Nordic environmentally friendly label 'the swan'. The purpose was to find out how much consumers actually know and use various labelling schemes. 869 households were contacted and asked to fill in a questionnaire...... it into consideration when I go shopping. The respondent was asked to pick the most suitable answer, which described her use of each label. 29% - also called 'the labelling blind' - responded that they basically only knew the recycling label and the Government controlled organic label 'Ø-mærket'. Another segment of 6...

  4. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  5. Labeling Schemes with Queries

    OpenAIRE

    2006-01-01

    We study the question of ``how robust are the known lower bounds of labeling schemes when one increases the number of consulted labels''. Let $f$ be a function on pairs of vertices. An $f$-labeling scheme for a family of graphs $\\cF$ labels the vertices of all graphs in $\\cF$ such that for every graph $G\\in\\cF$ and every two vertices $u,v\\in G$, the value $f(u,v)$ can be inferred by merely inspecting the labels of $u$ and $v$. This paper introduces a natural generalization: the notion of $f$-...

  6. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...... competitive insurance; this situation turns out to be at least as good as either of the alternatives...

  7. Enhanced arbitrated quantum signature scheme using Bell states

    Science.gov (United States)

    Wang, Chao; Liu, Jian-Wei; Shang, Tao

    2014-06-01

    We investigate the existing arbitrated quantum signature schemes as well as their cryptanalysis, including intercept-resend attack and denial-of-service attack. By exploring the loopholes of these schemes, a malicious signatory may successfully disavow signed messages, or the receiver may actively negate the signature from the signatory without being detected. By modifying the existing schemes, we develop counter-measures to these attacks using Bell states. The newly proposed scheme puts forward the security of arbitrated quantum signature. Furthermore, several valuable topics are also presented for further research of the quantum signature scheme.

  8. On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Wang Daoshun

    2010-01-01

    Full Text Available Abstract Traditional Secret Sharing (SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing (VSS schemes decode the secret without computation, but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing (Prob.VSS schemes for a binary image use only one subpixel to share the secret image; however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes, VSS schemes, and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert (transform a -SS scheme to a -VSS scheme for greyscale images. The generation of the shadow images (shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation, as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images, measured by average contrast, is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale -SS scheme to a more general case of greyscale -VSS scheme.

  9. Towards Symbolic Encryption Schemes

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.; Zenner, Erik

    2012-01-01

    Symbolic encryption, in the style of Dolev-Yao models, is ubiquitous in formal security models. In its common use, encryption on a whole message is specified as a single monolithic block. From a cryptographic perspective, however, this may require a resource-intensive cryptographic algorithm......-known Needham-Schroeder and Denning-Sacco protocols. To avoid such problems, we advocate the use of refined notions of symbolic encryption that have natural correspondence to standard cryptographic encryption schemes....

  10. Fabrication and characterization of novel Z-scheme photocatalyst WO{sub 3}/g-C{sub 3}N{sub 4} with high efficient visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shifu, E-mail: chshifu@chnu.edu.cn [Department of Chemistry, Anhui Science and Technology University, Anhui, Fengyang 233100 (China); Department of Chemistry, Huaibei Normal University, Anhui, Huaibei 235000 (China); Hu, Yingfei; Jiang, Xiaoliang; Meng, Sugang; Fu, Xianliang [Department of Chemistry, Huaibei Normal University, Anhui, Huaibei 235000 (China)

    2015-01-15

    Developing a high-efficiency visible light photocatalyst is always a research hotspot in photocatalytic field. In this study, a novel Z-scheme photocatalyst WO{sub 3}/g-C{sub 3}N{sub 4} with high efficient visible light photocatalytic activity was prepared via ball milling and heat treatment methods. The photocatalyst was characterized by X-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron spin resonance (ESR), and photoluminescence (PL). The photocatalytic activity was evaluated by degradation of methylene blue (MB) and fuchsin (BF) under visible light illumination. The results showed that composite WO{sub 3}/g-C{sub 3}N{sub 4} exhibits a much higher photocatalytic activity than a single g-C{sub 3}N{sub 4}. The rate constants of photocatalytic degradation of MB and BF for WO{sub 3}(5.0 wt.%)/g-C{sub 3}N{sub 4} are 4.77 times and 3.84 times that of pure g-C{sub 3}N{sub 4}. The characterization results by physical and chemical methods demonstrated that composite WO{sub 3}/g-C{sub 3}N{sub 4} is a typical Z-scheme photocatalyst. The enhancement of the photocatalytic activity may be attributed to the formation of the Z-scheme system between g-C{sub 3}N{sub 4} and WO{sub 3}, which could result in the photoexcited electrons of g-C{sub 3}N{sub 4} and photoexcited holes of WO{sub 3} participating in oxidation and reduction reactions, respectively. - Graphical abstract: When WO{sub 3} is combined with g-C{sub 3}N{sub 4}, a Z-scheme system photocatalyst may be formed because of the short distance between the VB of g-C{sub 3}N{sub 4} and the CB of WO{sub 3}. Consequently, the photogenerated electrons in the CB of g-C{sub 3}N{sub 4} and holes in the VB of WO{sub 3} exhibit excellent reduction and oxidation ability, respectively. - Highlights: • WO{sub 3}/g-C{sub 3}N{sub 4} photocatalyst with high efficient visible light activity was prepared. • The WO{sub 3}/g

  11. Development of a nitrogen-cooled cryoprobe with non-electric defrosting for use in corporeal cavities; Entwicklung einer stickstoffgekuehlten Kryosonde mit nicht-elektrischer Abtauung fuer den Einsatz in Koerperhoehlen

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, B. [Inst. fuer Luft- und Kaeltetechnik GmbH, Dresden (Germany); Herzog, R. [Inst. fuer Luft- und Kaeltetechnik GmbH, Dresden (Germany); Krantz, H. [Medizinische Akademie Dresden (Germany); Spoerl, E. [Medizinische Akademie Dresden (Germany)

    1994-12-31

    Cryotherapy has been used succesfully for about 20 years in the treatment of benign and malignant neoplasms of the skin or mucous membranes. A problematic circumstance is that cryoprobes applied while still body-warm induce formation of large ice crystals during the cooling process. To evade the adhesive forces developed by these crystals the probe must be defrosted at the end of the procedure. Cryoprobes for use in corporeal cavities must therefore be designed to specific technical requirements. This paper presents target specifications for the new development of a gynaecological cryoprobe. In this connection it explains the thermodynamic principle of function, its constructional realisation, and the technical concept employed for the design of a cryoprobe. (BWI) [Deutsch] Die Kryotherapie wird seit etwa 20 Jahren mit Erfolg zur Behandlung von gut- und boesartigen Neubildungen der Haut und der Schleimhaut eingesetzt. Bei koerperwarm aufgesetzten Kryosoden bilden sich allerdings waehrend des Abkuehlprozesses groessere Eiskristalle heraus, die Haftkraefte ausloesen, so dass die Sonde nach Therapieende abgetaut werden muss. Bei der Anwendung von Kryosonden in Koerperhoehlen ergeben sich deshalb besondere technische Forderungen. Der vorliegende Beitrag stellt die Zielstellung fuer die Neuentwicklung einer gynaekologischen Kryosonde vor. In diesem Zusammenhang wird auf das thermodynamische Funktionsprinzip sowie die konstruktive Umsetzung und das geraetetechnische Konzept eingegangen. (BWI)

  12. A New Deferred Sentencing Scheme

    Directory of Open Access Journals (Sweden)

    N. K. Chakravarti

    1968-10-01

    Full Text Available A new deferred sentencing scheme resembling double sampling scheme has been suggested from viewpoint of operational and administrative. It is recommended particularly when the inspection is destructive. The O.C. curves of the scheme for two sample sizes of 5 and 10 have been given.

  13. Two Improved Digital Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, two improved digital signature schemes are presented based on the design of directed signaturescheme [3]. The peculiarity of the system is that only if the scheme is specific recipient, the signature is authenticated.Since the scheme adds the screen of some information parameters, the difficulty of deciphered keys and the security ofdigital signature system are increased.

  14. CONSIDERATIONS CONCERNING GUARANTEE SCHEMES

    Directory of Open Access Journals (Sweden)

    EMILIA CLIPICI

    2013-05-01

    Full Text Available When a large withdrawal from banks occurs, customers withdraw their deposits, so banks are likely to go bankrupt because of liquidity problems. There are several mechanisms that allow the banking system to avoid the phenomenon of massive withdrawals from banks. The most effective one is the deposit insurance. The deposit insurance is seen primarily as a means of protecting depositors of credit institutions, and secondly as a means of ensuring the stability of the banking system. This article described deposit guarantee scheme in Romania and other country.

  15. On the role of SMA modeling in simulating NiTinol self-expanding stenting surgeries to assess the performance characteristics of mechanical and thermal activation schemes.

    Science.gov (United States)

    Saleeb, A F; Dhakal, B; Owusu-Danquah, J S

    2015-09-01

    The work is focused on a detailed simulation of the key stages involved in the NiTinol self-expanding stenting surgical procedure; i.e., crimping, deployment, SMA activation, as well as post-surgery steady-state cyclic behavior mimicking the systolic-to-diastolic pressure oscillations. To this end, a general multi-mechanism SMA model was utilized, whose calibration was completed using the test data from simple isothermal uniaxial tension experiments. The emphasis in the study was placed on the comparison of two alternative SMA activation protocols, in terms of both the immediate and long-term (post-surgery) performance characteristics. The first is 'hard' mechanical activation utilizing superelasticity, and the second is 'soft' thermal activation relying upon the combined one-way shape memory effect and constrained-recovery characteristics of the NiTinol material. The important findings are (1) the thermal activation protocol is far superior compared to the mechanical counterpart, from the point of view of lower magnitudes of the induced outward chronic forces, lesser developed stresses in the host tissue, as well as higher compression ratio with lesser crimping force for the same geometry of initial stent memory configuration, (2) the thermal activation protocol completely bypassed the complications of maintaining the high restraining force during deployment of the stent, and (3) there is no indication of any detrimental functional fatigue/degradation in the cured stenotic artery during cyclic pressure oscillations.

  16. Secure mediated certificateless signature scheme

    Institute of Scientific and Technical Information of China (English)

    YANG Chen; MA Wen-ping; WANG Xin-mei

    2007-01-01

    Ju et al proposed a certificateless signature scheme with instantaneous revocation by introducing security mediator (SEM) mechanism. This article presents a detailed cryptoanalysis of this scheme and shows that, in their proposed scheme, once a valid signature has been produced, the signer can recover his private key information and the instantaneous revocation property will be damaged. Furthermore, an improved mediated signature scheme, which can eliminate these disadvantages, is proposed, and security proof of the improved scheme under elliptic curve factorization problem (ECFP) assumption and bilinear computational diffie-hellman problem (BCDH) assumption is also proposed.

  17. Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors

    Science.gov (United States)

    Tae-Wook Kim,; Byong-Deok Choi,

    2010-03-01

    This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 μm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.

  18. Scheme of thinking quantum systems

    Science.gov (United States)

    Yukalov, V. I.; Sornette, D.

    2009-11-01

    A general approach describing quantum decision procedures is developed. The approach can be applied to quantum information processing, quantum computing, creation of artificial quantum intelligence, as well as to analyzing decision processes of human decision makers. Our basic point is to consider an active quantum system possessing its own strategic state. Processing information by such a system is analogous to the cognitive processes associated to decision making by humans. The algebra of probability operators, associated with the possible options available to the decision maker, plays the role of the algebra of observables in quantum theory of measurements. A scheme is advanced for a practical realization of decision procedures by thinking quantum systems. Such thinking quantum systems can be realized by using spin lattices, systems of magnetic molecules, cold atoms trapped in optical lattices, ensembles of quantum dots, or multilevel atomic systems interacting with electromagnetic field.

  19. Scheme of thinking quantum systems

    CERN Document Server

    Yukalov, V I

    2009-01-01

    A general approach describing quantum decision procedures is developed. The approach can be applied to quantum information processing, quantum computing, creation of artificial quantum intelligence, as well as to analyzing decision processes of human decision makers. Our basic point is to consider an active quantum system possessing its own strategic state. Processing information by such a system is analogous to the cognitive processes associated to decision making by humans. The algebra of probability operators, associated with the possible options available to the decision maker, plays the role of the algebra of observables in quantum theory of measurements. A scheme is advanced for a practical realization of decision procedures by thinking quantum systems. Such thinking quantum systems can be realized by using spin lattices, systems of magnetic molecules, cold atoms trapped in optical lattices, ensembles of quantum dots, or multilevel atomic systems interacting with electromagnetic field.

  20. Study on Thermal Energy Storage Modes and Defrosting Dynamic Characteristics of a PCM Based Air Source Heat Pump%空气源热泵相变蓄能除霜系统蓄热模式及除霜特性的研究

    Institute of Scientific and Technical Information of China (English)

    胡文举; 陈镇凯; 姜益强; 姚杨; 倪龙; 孙成

    2011-01-01

    In this paper,a novel phase change material ( PCM) based reversed-cycle defrosting method for air source heat pump (ASHP) was introduced and its PCM based heat exchanger (PCMHE) was designed. Three thermal energy storage modes were presented and experiments were carried out to test the efficiencies of thermal energy storage and defrosting respectively. By analyzing the experiment results, it was concluded that energy could be quickly stored in PCMHE with series thermal energy storage mode. Nevertheless,with sole and parallel modes,discharge and suction temperatures of the compressor were unusually high,while discharge and suction pressures and input power were relatively lower,also the thermal energy storage speed was very small,which meant that the ASHP could not work effectively. Furthermore,by comparing the PCM based reversed-cycle defrosting method with the traditional one,it was indicated that the former could decrease the defrosting time by 4 minutes at least,also shutting down of the ASHP unit due to low suction pressure protection could be avoided effectively by increasing the compressor's suction pressure of 0. 3 Mpa. Besides, when the system returned to the heating supply mode from the defrosting mode,with the PCM based defrosting method,the air temperature out of the indoor coil increased faster and was higher than the traditional method,which would benefit the indoor thermal comfort greatly.%本文阐述了基于相变蓄热的空气源热泵蓄能除霜系统及其相变蓄热器的设计,提出了3种蓄热模式并搭建了空气源热泵蓄能除霜试验台.通过对实验数据进行分析,认为串联蓄热模式时,系统可有效完成蓄热且相变蓄热器的蓄热速度较快;单独蓄热模式和并联蓄热模式时系统不能有效运行,压缩机的吸、排气温度偏高,而吸、排气压力偏低,功率偏低,相变材料蓄热速度非常小;除霜时,相变蓄能除霜系统的压缩机吸气压力比

  1. Pretzel scheme for CEPC

    Science.gov (United States)

    Geng, Huiping

    2016-11-01

    CEPC was proposed as an electron and positron collider ring with a circumference of 50-100 km to study the Higgs boson. Since the proposal was made, the lattice design for CEPC has been carried out and a preliminary conceptual design report has been written at the end of 2014. In this paper, we will describe the principles of pretzel scheme design, which is one of most important issues in CEPC lattice design. Then, we will show the modification of the lattice based on the lattice design shown in the Pre-CDR. The latest pretzel orbit design result will also be shown. The issues remained to be solved in the present design will be discussed and a brief summary will be given at the end.

  2. System Protection Schemes in Eastern Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Joana

    The Ph.D. project investigates different aspects of voltage stability in the power system of Eastern Denmark taking into account the large amount of wind power. In the project, a simple System Protection Scheme (SPS) against voltage instability in Eastern Denmark is developed. The SPS design...... outages in the southern part of the 132-kV system introduce further stress in the power system, eventually leading to a voltage collapse. The local System Protection Scheme against voltage collapse is designed as a response-based scheme, which is dependent on local indication of reactive and active power...... for the Eastern Danish power system, such as wind farm rejection, cascading line outages and power oscillations. E.g. Nordic inter-area oscillation modes and damping were easily detected from phasor data during the outage of the 400 kV tie-line between Eastern Denmark and Sweden. It is concluded that recording...

  3. Improved Ternary Subdivision Interpolation Scheme

    Institute of Scientific and Technical Information of China (English)

    WANG Huawei; QIN Kaihuai

    2005-01-01

    An improved ternary subdivision interpolation scheme was developed for computer graphics applications that can manipulate open control polygons unlike the previous ternary scheme, with the resulting curve proved to be still C2-continuous. Parameterizations of the limit curve near the two endpoints are given with expressions for the boundary derivatives. The split joint problem is handled with the interpolating ternary subdivision scheme. The improved scheme can be used for modeling interpolation curves in computer aided geometric design systems, and provides a method for joining two limit curves of interpolating ternary subdivisions.

  4. Formal Verification of NTRUEncrypt Scheme

    Directory of Open Access Journals (Sweden)

    Gholam Reza Moghissi

    2016-04-01

    Full Text Available In this paper we explore a mechanized verification of the NTRUEncrypt scheme, with the formal proof system Isabelle/HOL. More precisely, the functional correctness of this algorithm, in its reduced form, is formally verified with computer support. We show that this scheme is correct what is a necessary condition for the usefulness of any cryptographic encryption scheme. Besides, we present a convenient and application specific formalization of the NTRUEncrypt scheme in the Isabelle/HOL system that can be used in further study around the functional and security analysis of NTRUEncrypt family.

  5. BI-DIRECTIONAL ANONYMOUS IDENTITY AUTHENTICATION SCHEME FOR CLOUD COMPUTING BASED ON SECURITY ACTIVE BUNDLE%基于安全活跃束S AB的匿名双向云身份认证方案

    Institute of Scientific and Technical Information of China (English)

    张琼文; 吴承荣

    2014-01-01

    Dynamic and transparent cloud brings infinite possibility to people’s life;meanwhile it also imposes greater challenges on theincreasing privacy and security problems of digital identity in virtual world.Digital identity has a close relationship with information services.Before accessing or sharing the resources,the identities of both users and services providers should be authenticated each other.In particular,when the identity theft is rampant,telling authentication on users,partners and cloud services providers is the crucial measurement.Weanalyse the status quo of cloud identity authentication and the challenges encountering,and propose a scheme named “security active bundle(SAB)cloud identity authentication”based on predicate encryption and Active Bundle idea,which realises the bi-directional anonymousauthentication between the end user and the cloud,or among the clouds.This scheme strengthens the privacy protection of personal sensitiveinformation and no longer depends on the trusted third party,etc.%动态透明的云给人们的生活带来了无限的可能,同时也对虚拟世界中与日俱增的数字身份的隐私和安全问题提出了更大的挑战。数字身份和信息服务有着密切关系,在访问或分享资源前,用户和服务双方的身份都有必要先通过认证。特别是当身份窃取猖獗的时候,有力地用户认证、合作伙伴认证、云服务提供商认证等是至关重要的措施。分析云身份认证的现状和面临的挑战,基于谓词加密和Active Bundle思想提出了安全活跃束SAB(Security Active Bundle)云身份认证方案,实现了终端用户与云以及云之间的双向匿名认证,加强了个人敏感信息隐私保护和不再依赖可信第三方等。

  6. The impact of revised simplified Arakawa-Schubert scheme on the simulation of mean and diurnal variability associated with active and break phases of Indian summer monsoon using CFSv2

    Science.gov (United States)

    Ganai, Malay; Krishna, R. Phani Murali; Mukhopadhyay, P.; Mahakur, M.

    2016-08-01

    The impact of revised simplified Arakawa-Schubert (RSAS) convective parameterization scheme in Climate Forecast System (CFS) version 2 (CFSv2) on the simulation of active and break phases of Indian summer monsoon (ISM) has been investigated. The results revealed that RSAS showed better fidelity in simulating monsoon features from diurnal to daily scales during active and break periods as compared to SAS simulation. Prominent improvement can be noted in simulating diurnal phase of precipitation in RSAS over central India (CI) and equatorial Indian Ocean (EIO) region during active periods. The spatial distribution of precipitation largely improved in RSAS simulation during active and break episodes. CFSv2 with SAS simulation has noticeable dry bias over CI and wet bias over EIO region which appeared to be largely reduced in RSAS simulation during both phases of the intraseasonal oscillation (ISO). During active periods, RSAS simulates more realistic probability distribution function (PDF) in good agreement with the observation. The relative improvement has been identified in outgoing longwave radiation, monsoon circulations, and vertical velocities in RSAS over SAS simulation. The improvement of rainfall distribution appears to be contributed by proper simulation of convective rainfall in RSAS. CFSv2 with RSAS simulation is able to simulate observed diurnal cycle of rainfall over CI. It correctly reproduces the time of maximum rainfall over CI. It is found that the improved feedback between moisture and convective processes in RSAS may be attributed to its improved simulation. Besides improvement, RSAS could not reproduce proper tropospheric temperature, cloud hydrometeors over ISM domain which shows the scope for future development.

  7. Homographic scheme for Riccati equation

    CERN Document Server

    Dubois, François

    2011-01-01

    In this paper we present a numerical scheme for the resolution of matrix Riccati equation, usualy used in control problems. The scheme is unconditionnaly stable and the solution is definite positive at each time step of the resolution. We prove the convergence in the scalar case and present several numerical experiments for classical test cases.

  8. Chaotic communication scheme with multiplication

    Science.gov (United States)

    Bobreshov, A. M.; Karavaev, A. A.

    2007-05-01

    A new scheme of data transmission with nonlinear admixing is described, in which the two mutually inverse operations (multiplication and division) ensure multiplicative mixing of the informative and chaotic signals that provides a potentially higher degree of security. A special feature of the proposed scheme is the absence of limitations (related to the division by zero) imposed on the types of informative signals.

  9. Differential operators and automorphism schemes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The ring of global differential operators of a variety is in closed and deep relation with its automorphism scheme.This relation can be applied to the study of homogeneous schemes,giving some criteria of homogeneity,a generalization of Serre-Lang theorem,and some consequences about abelian varieties.

  10. Cost Based Droop Schemes for Economic Dispatch in Islanded Microgrids

    DEFF Research Database (Denmark)

    Chen, Feixiong; Chen, Minyou; Li, Qiang

    2017-01-01

    In this paper, cost based droop schemes are proposed, to minimize the total active power generation cost in an islanded microgrid (MG), while the simplicity and decentralized nature of the droop control are retained. In cost based droop schemes, the incremental costs of distributed generators (DGs......) are embedded into the droop schemes, where the incremental cost is a derivative of the DG cost function with respect to output power. In the steady state, DGs share a single common frequency, and cost based droop schemes equate incremental costs of DGs, thus minimizing the total active power generation cost......, in terms of the equal incremental cost principle. Finally, simulation results in an islanded MG with high penetration of intermittent renewable energy sources are presented, to demonstrate the eectiveness, as well as plug and play capability of the cost based droop schemes....

  11. Can adding web-based support to UK primary care exercise referral schemes improve patients’ physical activity levels? Intervention development for the e-coachER study.

    Directory of Open Access Journals (Sweden)

    Adrian Taylor

    2015-10-01

    -monitoring health behaviour and health, as well as modifiable options for local physical activity options. Conclusion: The Lifeguide platform for e-coachER is able to collect data on individual usage, and this will be used, along with semi-structured interviews, to conduct a process evaluation to fully understand if, for whom, and how the intervention facilitated long-term PA changes. Supported with funding from the NIHR (HTA Project: 13/25/20

  12. Multiuser Switched Diversity Scheduling Schemes

    CERN Document Server

    Shaqfeh, Mohammad; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback sys...

  13. The Occupational Pension Schemes Survey 2006

    OpenAIRE

    Sarah Levy; David Miller

    2008-01-01

    Presents findings on the number of schemes, their membership and contributions to schemes by employers and employeesThis article presents findings on the number of occupational pension schemes in 2006, their membership and contributions to schemes by employers and employees. It is based on the Occupational Pension Schemes Annual Report (2006 edition). The findings distinguish between public and private sector schemes and include breakdowns by scheme status (open, closed, frozen or winding up)...

  14. Coordinated renewable energy support schemes

    DEFF Research Database (Denmark)

    Morthorst, P.E.; Jensen, S.G.

    2006-01-01

    This paper illustrates the effect that can be observed when support schemes for renewable energy are regionalised. Two theoretical examples are used to explain interactive effects on, e.g., the price of power, conditions for conventional power producers, and changes in import and export of power...... RES-E support schemes already has a common liberalised power market. In this case the introduction of a common support scheme for renewable technologies will lead to more efficient sitings of renewable plants, improving economic and environmental performance of the total power system...

  15. Schemes for Deterministic Polynomial Factoring

    CERN Document Server

    Ivanyos, Gábor; Saxena, Nitin

    2008-01-01

    In this work we relate the deterministic complexity of factoring polynomials (over finite fields) to certain combinatorial objects we call m-schemes. We extend the known conditional deterministic subexponential time polynomial factoring algorithm for finite fields to get an underlying m-scheme. We demonstrate how the properties of m-schemes relate to improvements in the deterministic complexity of factoring polynomials over finite fields assuming the generalized Riemann Hypothesis (GRH). In particular, we give the first deterministic polynomial time algorithm (assuming GRH) to find a nontrivial factor of a polynomial of prime degree n where (n-1) is a smooth number.

  16. Provable Secure Identity Based Generalized Signcryption Scheme

    CERN Document Server

    Yu, Gang; Shen, Yong; Han, Wenbao

    2010-01-01

    According to actual needs, generalized signcryption scheme can flexibly work as an encryption scheme, a signature scheme or a signcryption scheme. In this paper, firstly, we give a security model for identity based generalized signcryption which is more complete than existing model. Secondly, we propose an identity based generalized signcryption scheme. Thirdly, we give the security proof of the new scheme in this complete model. Comparing with existing identity based generalized signcryption, the new scheme has less implementation complexity. Moreover, the new scheme has comparable computation complexity with the existing normal signcryption schemes.

  17. An 8-bit Data Driving Scheme Based on Two-Step Digital-to-Analog Conversion for Integrated Data Drivers of Active-Matrix Organic Light-Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Choi, Byong-Deok

    2012-03-01

    The two-step digital-to-analog conversion (DAC) scheme has been reported to be very area-efficient for thin-film transistor-liquid crystal display (TFT-LCD) data driver ICs, but it is not as well suited as it is for polycrystalline silicon (poly-Si) TFT integrated circuits. The charge redistribution in the two-step DAC process requires an operational amplifier in principle, which is most challenging for poly-Si TFT circuits. The proposed two-step DAC for active-matrix organic light-emitting diodes (AMOLEDs) makes the operational amplifier unnecessary by appropriately exploiting the preexisting capacitors in the pixel to compensate for the characteristic variations of TFTs. Moreover, the second-step DAC occurs at the same time as threshold voltage compensation, and it does not require additional time. By thoroughly analyzing area efficiency depending on the resolution decomposition between the first- and second-step DACs, we found that 5-bit coarse plus 3-bit fine DACs are best in terms of circuit area. When we designed a layout of the proposed 8-bit DAC on the basis of the 4 µm design rules, the DAC circuit area is no more than 72×637 µm2, which, to the best of our knowledge, is the most compact to date.

  18. Scheme Design for the Giant Forging Hydraulic Press Active Synchronous Control System%巨型模锻液压机主动同步控制方案的设计

    Institute of Scientific and Technical Information of China (English)

    刘忠伟

    2012-01-01

    The synchronous control system is the essential device to the giant forging hydraulic press. Its synchronization control performance will directly determine product quality. The main causes of working cylinder asynchronism and its effect on synchronous control performance were analyzed. According to the practical problems of synchronous control application, an active synchronism control scheme was proposed based on multi-point driver.%同步控制系统是巨型模锻液压机上必备的关键装置,其同步控制性能的好坏将直接决定产品的质量.在分析主工作缸不同步的成因及对同步控制性能影响的基础上,根据巨型模锻液压机同步控制的实际应用问题,提出一种基于多点驱动的主动同步控制方案.

  19. Capacity-achieving CPM schemes

    CERN Document Server

    Perotti, Alberto; Benedetto, Sergio; Montorsi, Guido

    2008-01-01

    The pragmatic approach to coded continuous-phase modulation (CPM) is proposed as a capacity-achieving low-complexity alternative to the serially-concatenated CPM (SC-CPM) coding scheme. In this paper, we first perform a selection of the best spectrally-efficient CPM modulations to be embedded into SC-CPM schemes. Then, we consider the pragmatic capacity (a.k.a. BICM capacity) of CPM modulations and optimize it through a careful design of the mapping between input bits and CPM waveforms. The so obtained schemes are cascaded with an outer serially-concatenated convolutional code to form a pragmatic coded-modulation system. The resulting schemes exhibit performance very close to the CPM capacity without requiring iterations between the outer decoder and the CPM demodulator. As a result, the receiver exhibits reduced complexity and increased flexibility due to the separation of the demodulation and decoding functions.

  20. Underground hydro scheme for Ullapool

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Scoltish and Southern Energy has awarded a contract for a new hydropower plant Scotland, the company's first hydro project since the 1960s. The S6 million scheme will be built by Miller Civil Engineering Services Ltd.

  1. New Ideas on Labeling Schemes

    DEFF Research Database (Denmark)

    Rotbart, Noy Galil

    evaluation of fully dynamic labeling schemes. Due to a connection between adjacency labeling schemes and the graph theoretical study of induced universal graphs, we study these in depth and show novel results for bounded degree graphs and power-law graphs. We also survey and make progress on the related......With ever increasing size of graphs, many distributed graph systems emerged to store, preprocess and analyze them. While such systems ease up congestion on servers, they incur certain penalties compared to centralized data structure. First, the total storage required to store a graph...... in a distributed fashion increases. Second, attempting to answer queries on vertices of a graph stored in a distributed fashion can be significantly more complicated. In order to lay theoretical foundations to the first penalty mentioned a large body of work concentrated on labeling schemes. A labeling scheme...

  2. A Novel Iris Segmentation Scheme

    Directory of Open Access Journals (Sweden)

    Chen-Chung Liu

    2014-01-01

    Full Text Available One of the key steps in the iris recognition system is the accurate iris segmentation from its surrounding noises including pupil, sclera, eyelashes, and eyebrows of a captured eye-image. This paper presents a novel iris segmentation scheme which utilizes the orientation matching transform to outline the outer and inner iris boundaries initially. It then employs Delogne-Kåsa circle fitting (instead of the traditional Hough transform to further eliminate the outlier points to extract a more precise iris area from an eye-image. In the extracted iris region, the proposed scheme further utilizes the differences in the intensity and positional characteristics of the iris, eyelid, and eyelashes to detect and delete these noises. The scheme is then applied on iris image database, UBIRIS.v1. The experimental results show that the presented scheme provides a more effective and efficient iris segmentation than other conventional methods.

  3. Good governance for pension schemes

    CERN Document Server

    Thornton, Paul

    2011-01-01

    Regulatory and market developments have transformed the way in which UK private sector pension schemes operate. This has increased demands on trustees and advisors and the trusteeship governance model must evolve in order to remain fit for purpose. This volume brings together leading practitioners to provide an overview of what today constitutes good governance for pension schemes, from both a legal and a practical perspective. It provides the reader with an appreciation of the distinctive characteristics of UK occupational pension schemes, how they sit within the capital markets and their social and fiduciary responsibilities. Providing a holistic analysis of pension risk, both from the trustee and the corporate perspective, the essays cover the crucial role of the employer covenant, financing and investment risk, developments in longevity risk hedging and insurance de-risking, and best practice scheme administration.

  4. Efficient and provably secure identification scheme without random oracles

    Institute of Scientific and Technical Information of China (English)

    LI Yan-ping; WANG Yu-min

    2009-01-01

    The research on the identification scheme is an important and active area in computer and communication security. A series of identification schemes were proposed to improve the efficiency and security of the protocols by various methods. Based on the hardness assumption of the discrete logarithm problem in a gap Diffie-Hellman group and the difficulty of the collusion attack algorithm with k traitors, an efficient identification scheme is presented. Without random oracle models, the proposed scheme is then proved secure against impersonation and reset attacks in both concurrent and reset attack setting. Since the proposed scheme is simple, memory-saving, computation-efficient, and perfectly-secure, it is well suitable for use in smart cards.

  5. The Influence of Second-Hand Cigarette Smoke Exposure during Childhood and Active Cigarette Smoking on Crohn's Disease Phenotype Defined by the Montreal Classification Scheme in a Western Cape Population, South Africa.

    Directory of Open Access Journals (Sweden)

    Tawanda Chivese

    Full Text Available Smoking may worsen the disease outcomes in patients with Crohn's disease (CD, however the effect of exposure to second-hand cigarette smoke during childhood is unclear. In South Africa, no such literature exists. The aim of this study was to investigate whether disease phenotype, at time of diagnosis of CD, was associated with exposure to second-hand cigarette during childhood and active cigarette smoking habits.A cross sectional examination of all consecutive CD patients seen during the period September 2011-January 2013 at 2 large inflammatory bowel disease centers in the Western Cape, South Africa was performed. Data were collected via review of patient case notes, interviewer-administered questionnaire and clinical examination by the attending gastroenterologist. Disease phenotype (behavior and location was evaluated at time of diagnosis, according to the Montreal Classification scheme. In addition, disease behavior was stratified as 'complicated' or 'uncomplicated', using predefined definitions. Passive cigarette smoke exposure was evaluated during 3 age intervals: 0-5, 6-10, and 11-18 years.One hundred and ninety four CD patients were identified. Cigarette smoking during the 6 months prior to, or at time of diagnosis was significantly associated with ileo-colonic (L3 disease (RRR = 3.63; 95% CI, 1.32-9.98, p = 0.012 and ileal (L1 disease (RRR = 3.54; 95% CI, 1.06-11.83, p = 0.040 compared with colonic disease. In smokers, childhood passive cigarette smoke exposure during the 0-5 years age interval was significantly associated with ileo-colonic CD location (RRR = 21.3; 95% CI, 1.16-391.55, p = 0.040. No significant association between smoking habits and disease behavior at diagnosis, whether defined by the Montreal scheme, or stratified as 'complicated' vs 'uncomplicated', was observed.Smoking habits were associated with ileo-colonic (L3 and ileal (L1 disease at time of diagnosis in a South African cohort.

  6. Breeding schemes in reindeer husbandry

    Directory of Open Access Journals (Sweden)

    Lars Rönnegård

    2003-04-01

    Full Text Available The objective of the paper was to investigate annual genetic gain from selection (G, and the influence of selection on the inbreeding effective population size (Ne, for different possible breeding schemes within a reindeer herding district. The breeding schemes were analysed for different proportions of the population within a herding district included in the selection programme. Two different breeding schemes were analysed: an open nucleus scheme where males mix and mate between owner flocks, and a closed nucleus scheme where the males in non-selected owner flocks are culled to maximise G in the whole population. The theory of expected long-term genetic contributions was used and maternal effects were included in the analyses. Realistic parameter values were used for the population, modelled with 5000 reindeer in the population and a sex ratio of 14 adult females per male. The standard deviation of calf weights was 4.1 kg. Four different situations were explored and the results showed: 1. When the population was randomly culled, Ne equalled 2400. 2. When the whole population was selected on calf weights, Ne equalled 1700 and the total annual genetic gain (direct + maternal in calf weight was 0.42 kg. 3. For the open nucleus scheme, G increased monotonically from 0 to 0.42 kg as the proportion of the population included in the selection programme increased from 0 to 1.0, and Ne decreased correspondingly from 2400 to 1700. 4. In the closed nucleus scheme the lowest value of Ne was 1300. For a given proportion of the population included in the selection programme, the difference in G between a closed nucleus scheme and an open one was up to 0.13 kg. We conclude that for mass selection based on calf weights in herding districts with 2000 animals or more, there are no risks of inbreeding effects caused by selection.

  7. An arbitrated quantum signature scheme

    CERN Document Server

    Zeng, G; Zeng, Guihua; Keitel, Christoph H.

    2002-01-01

    The general principle for a quantum signature scheme is proposed and investigated based on ideas from classical signature schemes and quantum cryptography. The suggested algorithm is implemented by a symmetrical quantum key cryptosystem and Greenberger-Horne-Zeilinger (GHZ) triplet states and relies on the availability of an arbitrator. We can guarantee the unconditional security of the algorithm, mostly due to the correlation of the GHZ triplet states and the use of quantum one-time pads.

  8. The salivary testosterone and cortisol response to three loading schemes.

    Science.gov (United States)

    Crewther, Blair; Cronin, John; Keogh, Justin; Cook, Christian

    2008-01-01

    This aim of this study was to examine the free hormone (in saliva) responses to squat workouts performed by recreationally weight-trained males, using either a power (8 sets of 6 reps, 45% 1 repetition maximum [1RM], 3-minute rest periods, ballistic movements), hypertrophy (10 sets of 10 reps, 75% 1RM, 2-minute rest periods, controlled movements), or maximal strength scheme (6 sets of 4 reps, 88% 1RM, 4-minute rest periods, explosive intent). To determine the relative importance of the different training variables, these schemes were equated by workout duration with the power and strength schemes also equated by load volume. Salivary testosterone (T) and cortisol (C) both increased following the hypertrophy scheme (P hormonal change across the power and maximal strength schemes (P > 0.05). In general, the postexercise T and C responses to the hypertrophy scheme exceeded the other two schemes (P workout duration may explain the endocrine differences observed. The similar T and C responses to the power and maximal strength schemes (of equal volume) support such a view and suggest that differences in load intensity, rest periods, and technique are secondary to volume. Because the acute hormonal responses to resistance exercise contribute to protein metabolism, then load volume may be the most important workout variable activating the endocrine system and stimulating muscle growth.

  9. Provable Secure Identity Based Generalized Signcryption Scheme

    OpenAIRE

    Yu, Gang; Ma, Xiaoxiao; Shen, Yong; Han, Wenbao

    2010-01-01

    According to actual needs, generalized signcryption scheme can flexibly work as an encryption scheme, a signature scheme or a signcryption scheme. In this paper, firstly, we give a security model for identity based generalized signcryption which is more complete than existing model. Secondly, we propose an identity based generalized signcryption scheme. Thirdly, we give the security proof of the new scheme in this complete model. Comparing with existing identity based generalized signcryption...

  10. Study on the sudation function of sweat gland-like cells differentiated from umbilical cord mesenchymal stem cells after being frozen and defrosted%汗腺样细胞经冻存复苏后再生汗腺功能的研究

    Institute of Scientific and Technical Information of China (English)

    马奎; 鲁刚; 杨思明; 孙同柱; 付小兵; 盛志勇

    2011-01-01

    To explore the biological characteristics and the function of sweat gland-like cells trans-differentiated from umbilical cord mcscnchymal stem cells (UCMSCs) after being deep freeze storage. Methods; Human UCMSCs and sweat gland cells were isolated, cultured and identified with specific markers. They were co-cultured to transform the UCMSCs to sweat gland-like cells. After being deep frozen and defrosted, the stem cells, which exhibited the phenotype of sweat gland cells, were implanted into scald injured paws of nude mice. The regeneration of the sweat gland cells was observed. Results;The transdiffcrcntiatcd sweat gland-like cells were successfully implanted into the scald paws of nude mice after being frozen and defrosted, which regenerated the function of perspiration. Pathological observation showed that sweat glands were regenerated. Conclusions: UCMSCs can be transdiffcrcntiatcd into sweat gland-like cells in vitro, and the deep frozen and defrosted sweat gland like cells can be implanted into a fresh wound to regenerate sweat glands.%目的:研究由人脐带间充质干细胞(UCMSCs)分化而来的汗腺样细胞在冻存与复苏后的生物学活性与促汗腺再生能力.方法:分离培养人UCMSCs 和人汗腺细胞,通过两种细胞共培养方式促进UCMSCs向汗腺细胞分化.分化后的干细胞经冻存、复苏处理后,局部移植于裸鼠烫伤脚掌,通过组织学观察和发汗试验观察汗腺组织再生修复情况.结果:由UCMSCs分化而来的汗腺样细胞经冻存、复苏、移植于裸鼠脚掌创面后,能够在创面形成汗腺结构并具有发汗功能.结论:UCMSCs经诱导分化为汗腺样细胞后,经冻存和复苏处理,在体移植后仍能够有效促进受损汗腺的修复与再生,有望为大面积重度烧伤患者汗腺的修复提供充足的种子细胞.

  11. Top-quark pair production in a running mass scheme

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2013-11-15

    Between the Tevatron and LHC, top-quark physics is now becoming an area for precision physics. This has lead to an increase in theoretical activity to match the experimental accuracy of top anti-top production. We discuss the difficulty in properly defining the top-quark mass as measured by experiments and present results for differential distributions of top-quark pair production in a running mass scheme. The use of such a scheme shows better convergence in the perturbative expansion and improves the scale dependence as opposed to the typical on-shell scheme.

  12. Nonlinear secret image sharing scheme.

    Science.gov (United States)

    Shin, Sang-Ho; Lee, Gil-Je; Yoo, Kee-Young

    2014-01-01

    Over the past decade, most of secret image sharing schemes have been proposed by using Shamir's technique. It is based on a linear combination polynomial arithmetic. Although Shamir's technique based secret image sharing schemes are efficient and scalable for various environments, there exists a security threat such as Tompa-Woll attack. Renvall and Ding proposed a new secret sharing technique based on nonlinear combination polynomial arithmetic in order to solve this threat. It is hard to apply to the secret image sharing. In this paper, we propose a (t, n)-threshold nonlinear secret image sharing scheme with steganography concept. In order to achieve a suitable and secure secret image sharing scheme, we adapt a modified LSB embedding technique with XOR Boolean algebra operation, define a new variable m, and change a range of prime p in sharing procedure. In order to evaluate efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB) and 1.74t⌈log2 m⌉ bit-per-pixel (bpp), respectively.

  13. Energy partitioning schemes: a dilemma.

    Science.gov (United States)

    Mayer, I

    2007-01-01

    Two closely related energy partitioning schemes, in which the total energy is presented as a sum of atomic and diatomic contributions by using the "atomic decomposition of identity", are compared on the example of N,N-dimethylformamide, a simple but chemically rich molecule. Both schemes account for different intramolecular interactions, for instance they identify the weak C-H...O intramolecular interactions, but give completely different numbers. (The energy decomposition scheme based on the virial theorem is also considered.) The comparison of the two schemes resulted in a dilemma which is especially striking when these schemes are applied for molecules distorted from their equilibrium structures: one either gets numbers which are "on the chemical scale" and have quite appealing values at the equilibrium molecular geometries, but exhibiting a counter-intuitive distance dependence (the two-center energy components increase in absolute value with the increase of the interatomic distances)--or numbers with too large absolute values but "correct" distance behaviour. The problem is connected with the quick decay of the diatomic kinetic energy components.

  14. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  15. Pension scheme in Austria

    Directory of Open Access Journals (Sweden)

    Greta Alikaj

    2015-07-01

    Full Text Available Driven by unfavorable demographic developments and unsustainable, outdated or fragmented systems, pension reform has been at the top of political agendas across the globe for many years now (Prinz, Stanovnik & Stropnik, 2000. Over the last two decades, almost all western European countries have been trimming their public pension systems in an effort to strengthen pension sustainability. One main target of reform was to increase the retirement age. Other measures (e.g. changing the pension calculation, broadening the assessment base, changing the adjustment mechanism were designed to lower replacement rates. The reform process in the wide range of countries addressed by this survey differs considerably from country to country. This is why Allianz first introduced the Pension Sustainability Index (PSI, which combines the various characteristics of pension systems with the factors that influence them to help track and evaluate policy changes made in different countries around the world. In addressing the sustainability of a country’s public pension system, the PSI can give an indication of a country’s need for reforms to maintain long-term financial sustainability. This can be difficult to assess given the many country-specific institutional, technical and legal parameters. The PSI is able to evaluate the long-term sustainability of national pension systems and thus the pressure on governments to reform these (International pension Papers, 1.2014. The speed of reform, however, differs between countries. Those which recently introduced major reforms were able to improve in the PSI ranking because of active steps taken, while others were lost in comparison due to their passive policymaking.

  16. Discrete-time H-infinity robust active queue management scheme for uncertain TCP flow model%不确定TCP流模型的离散H∞鲁棒主动队列管理算法

    Institute of Scientific and Technical Information of China (English)

    周川; 何俊伟; 陈庆伟

    2013-01-01

    Considering the problem of congestion control for the time-varying and uncertain TCP/IP network, we proposed a novel discrete-time robust active queue management (AQM) scheme based on H-infinity feedback control for the TCP flow model with link capacity disturbance and parameter uncertainties simultaneously. In this method, the bandwidth occupied by short-lived connections is treated as the external disturbances, and the effect of both delay and parameter uncertainties is taken into account for the TCP/AQM system model. By using Lyapunov stability theory and LMI techniques, we propose a discrete-time robust H-infinity AQM controller to guarantee the asymptotic stability and robustness of the queue length response of a router queues. Finally the NS-2 simulation results demonstrate effectiveness of the proposed method.%针对TCP/IP网络存在参数时变和不确定性下的拥塞控制问题,提出一种新的基于H∞状态反馈控制的离散鲁棒主动列队管理算法(AQM).该方法针对不确定TCP流模型,将短期突发流所占据的带宽作为系统的外部干扰,同时考虑时滞和参数不确定性因素,基于Lyapunov稳定性理论和线性矩阵不等式技术,设计了离散鲁棒状态反馈控制器以保证路由器队列响应的稳定性和鲁棒性.最后,通过NS-2仿真验证了本文方法的有效性.

  17. Comparing document classification schemes using k-means clustering

    OpenAIRE

    Šivić, Artur; Žmak, Lovro; Dalbelo Bašić, Bojana; Moens, Marie-Francine

    2008-01-01

    In this work, we jointly apply several text mining methods to a corpus of legal documents in order to compare the separation quality of two inherently different document classification schemes. The classification schemes are compared with the clusters produced by the k-means algorithm. In the future, we believe that our comparison method will be coupled with semi-supervised and active learning techniques. Also, this paper presents the idea of combining k-means and Principal Component Analysis...

  18. Cost-prioritized droop schemes for autonomous microgrids

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    centralized optimal dispatch control. To better adapt to this non-uniformity, an alternative viewpoint based on reducing the Total Generation Cost (TGC including fuel cost, emission penalty and other operational concerns) of the microgrid is discussed, from which two new cost-prioritized droop schemes...... are developed. The schemes operate by tuning the dispatch priorities of the DGs and curve shapes of their resulting active power versus frequency plots. Their effective reduction of TGC has been verified through simulation....

  19. Doppler Shift Compensation Schemes in VANETs

    Directory of Open Access Journals (Sweden)

    F. Nyongesa

    2015-01-01

    Full Text Available Over the last decade vehicle-to-vehicle (V2V communication has received a lot of attention as it is a crucial issue in intravehicle communication as well as in Intelligent Transportation System (ITS. In ITS the focus is placed on integration of communication between mobile and fixed infrastructure to execute road safety as well as nonsafety information dissemination. The safety application such as emergence alerts lays emphasis on low-latency packet delivery rate (PDR, whereas multimedia and infotainment call for high data rates at low bit error rate (BER. The nonsafety information includes multimedia streaming for traffic information and infotainment applications such as playing audio content, utilizing navigation for driving, and accessing Internet. A lot of vehicular ad hoc network (VANET research has focused on specific areas including channel multiplexing, antenna diversity, and Doppler shift compensation schemes in an attempt to optimize BER performance. Despite this effort few surveys have been conducted to highlight the state-of-the-art collection on Doppler shift compensation schemes. Driven by this cause we survey some of the recent research activities in Doppler shift compensation schemes and highlight challenges and solutions as a stock-taking exercise. Moreover, we present open issues to be further investigated in order to address the challenges of Doppler shift in VANETs.

  20. A robust anonymous biometric-based remote user authentication scheme using smart cards

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Das

    2015-04-01

    Full Text Available Several biometric-based remote user authentication schemes using smart cards have been proposed in the literature in order to improve the security weaknesses in user authentication system. In 2012, An proposed an enhanced biometric-based remote user authentication scheme using smart cards. It was claimed that the proposed scheme is secure against the user impersonation attack, the server masquerading attack, the password guessing attack, and the insider attack and provides mutual authentication between the user and the server. In this paper, we first analyze the security of An’s scheme and we show that this scheme has three serious security flaws in the design of the scheme: (i flaw in user’s biometric verification during the login phase, (ii flaw in user’s password verification during the login and authentication phases, and (iii flaw in user’s password change locally at any time by the user. Due to these security flaws, An’s scheme cannot support mutual authentication between the user and the server. Further, we show that An’s scheme cannot prevent insider attack. In order to remedy the security weaknesses found in An’s scheme, we propose a new robust and secure anonymous biometric-based remote user authentication scheme using smart cards. Through the informal and formal security analysis, we show that our scheme is secure against all possible known attacks including the attacks found in An’s scheme. The simulation results of our scheme using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool ensure that our scheme is secure against passive and active attacks. In addition, our scheme is also comparable in terms of the communication and computational overheads with An’s scheme and other related existing schemes. As a result, our scheme is more appropriate for practical applications compared to other approaches.

  1. Small-scale classification schemes

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2004-01-01

    . While coordination mechanisms focus on how classification schemes enable cooperation among people pursuing a common goal, boundary objects embrace the implicit consequences of classification schemes in situations involving conflicting goals. Moreover, the requirements specification focused on functional...... requirements and provided little information about why these requirements were considered relevant. This stands in contrast to the discussions at the project meetings where the software engineers made frequent use of both abstract goal descriptions and concrete examples to make sense of the requirements....... This difference between the written requirements specification and the oral discussions at the meetings may help explain software engineers’ general preference for people, rather than documents, as their information sources....

  2. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min

    2014-02-26

    We present a homogenization scheme for acoustic metamaterials that is based on reproducing the lowest orders of scattering amplitudes from a finite volume of metamaterials. This approach is noted to differ significantly from that of coherent potential approximation, which is based on adjusting the effective-medium parameters to minimize scatterings in the long-wavelength limit. With the aid of metamaterials’ eigenstates, the effective parameters, such as mass density and elastic modulus can be obtained by matching the surface responses of a metamaterial\\'s structural unit cell with a piece of homogenized material. From the Green\\'s theorem applied to the exterior domain problem, matching the surface responses is noted to be the same as reproducing the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost exactly with numerical simulations and experiments and the scheme\\'s validity is constrained by the number of dominant surface multipoles instead of the usual long-wavelength assumption. In particular, the validity extends to the full band in one dimension and to regimes near the boundaries of the Brillouin zone in two dimensions.

  3. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben;

    2016-01-01

    variants such as, for example, small distances in trees [Alstrup et al., SODA, 2003]. We improve the known upper and lower bounds of exact distance labeling by showing that 1/4 log2(n) bits are needed and that 1/2 log2(n) bits are sufficient. We also give (1 + ε)-stretch labeling schemes using Theta...

  4. Electrical Injection Schemes for Nanolasers

    DEFF Research Database (Denmark)

    Lupi, Alexandra; Chung, Il-Sug; Yvind, Kresten

    2014-01-01

    Three electrical injection schemes based on recently demonstrated electrically pumped photonic crystal nanolasers have been numerically investigated: 1) a vertical p-i-n junction through a post structure; 2) a lateral p-i-n junction with a homostructure; and 3) a lateral p-i-n junction with a bur...

  5. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben;

    2016-01-01

    We consider distance labeling schemes for trees: given a tree with n nodes, label the nodes with binary strings such that, given the labels of any two nodes, one can determine, by looking only at the labels, the distance in the tree between the two nodes. A lower bound by Gavoille et al. [Gavoill...

  6. Efficient adaptive fuzzy control scheme

    NARCIS (Netherlands)

    Papp, Z.; Driessen, B.J.F.

    1995-01-01

    The paper presents an adaptive nonlinear (state-) feedback control structure, where the nonlinearities are implemented as smooth fuzzy mappings defined as rule sets. The fine tuning and adaption of the controller is realized by an indirect adaptive scheme, which modifies the parameters of the fuzzy

  7. Fair Electronic Payment Scheme Based on DSA

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-bin; HONG Fan; ZHU Xian

    2005-01-01

    We present a multi-signature scheme based on DSA and describes a fair electronic payment scheme based on improved DSA signatures. The scheme makes both sides in equal positions during the course of electronic transaction. A Trusted Third Party (TTP) is involved in the scheme to guarantee the fairness of the scheme for both sides. However, only during the course of registration and dispute resolution will TTP be needed. TTP is not needed during the normal payment stage.

  8. Quantum group blind signature scheme without entanglement

    Science.gov (United States)

    Xu, Rui; Huang, Liusheng; Yang, Wei; He, Libao

    2011-07-01

    In this paper we propose a quantum group blind signature scheme designed for distributed e-voting system. Our scheme combines the properties of group signature and blind signature to provide anonymity of voters in an e-voting system. The unconditional security of our scheme is ensured by quantum mechanics. Without employing entanglement, the proposed scheme is easier to be realized comparing with other quantum signature schemes.

  9. Technology of Laser Protection and Defrosting Film①

    Institute of Scientific and Technical Information of China (English)

    CHEYing; SHENYuzhi; 等

    1997-01-01

    A compound coating of electrically conductive and visible transparent film and laser protective film has been developed,this coating has light densities of no less than 4 against 0.53μm and no less than 3 against 1.06μm in the range of ±30°angular field.The average transmittance value as high as 60% from 0.4μm to 0.7μm has been achieved.The structures of the laser protective filters are compared.The refractive index of a compound material used in the matching layer has been given.Measured results of the laser protective film coating are compared with that of the compound coating.

  10. WEIGHTED COMPACT SCHEME FOR SHOCK CAPTURING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new class of finite difference schemes--the weighted compact schemes are proposed. According to the idea of the WENO schemes, the weighted compact scheme is constructed by a combination of the approximations of derivatives on candidate stencils with properly assigned weights so that the non-oscillatory property is achieved when discontinuities appear. The primitive function reconstruction method of ENO schemes is applied to obtain the conservative form of the weighted compact scheme. This new scheme not only preserves the characteristic of standard compact schemes and achieves high order accuracy and high resolution using a compact stencil,but also can accurately capture shock waves and discontinuities without oscillation, Numerical examples show that the new scheme is very promising and successful.``

  11. Ion Polarization Scheme for MEIC

    CERN Document Server

    Kondratenko, A M; Filatov, Yu N; Derbenev, Ya S; Lin, F; Morozov, V S; Zhang, Y

    2016-01-01

    The choice of a figure 8 shape for the booster and collider rings of MEIC opens wide possibilities for preservation of the ion polarization during beam acceleration as well as for control of the polarization at the collider's interaction points. As in the case of accelerators with Siberian snakes, the spin tune is energy independent but is equal to zero instead of one half. The figure-8 topology eliminates the effect of arcs on the spin motion. There appears a unique opportunity to control the polarization of any particle species including deuterons, using longitudinal fields of small integrated strength (weak solenoids). Contrary to existing schemes, using weak solenoids in figure-8 colliders, one can control the polarization at the interaction points without essentially any effect on the beam's orbital characteristics. A universal scheme for control of the polarization using weak solenoids provides an elegant solution to the problem of ion acceleration completely eliminating resonant beam depolarization. It...

  12. Wrong way recollement for schemes

    OpenAIRE

    Jorgensen, Peter

    2005-01-01

    A recollement of triangulated categories makes it possible to view one such category as being glued together from two others. The prototypical example is that D(X), a suitable derived category of sheaves on the topological space X, has a recollement in terms of D(Z) and D(U) when Z is a closed subset of X and U is the open complement. This note gives a different, "wrong way" recollement in the scheme case.

  13. Parabolic sheaves on logarithmic schemes

    OpenAIRE

    Borne, Niels; Vistoli, Angelo

    2010-01-01

    We show how the natural context for the definition of parabolic sheaves on a scheme is that of logarithmic geometry. The key point is a reformulation of the concept of logarithmic structure in the language of symmetric monoidal categories, which might be of independent interest. Our main result states that parabolic sheaves can be interpreted as quasi-coherent sheaves on certain stacks of roots.

  14. Practical E-Payment Scheme

    Directory of Open Access Journals (Sweden)

    Mohammad Al-Fayoumi

    2010-05-01

    Full Text Available E-payment is now one of the most central research areas in e-commerce, mainly regarding online and offline payment scenarios. Customers are generally passive in e-commerce transaction. Relied on a blind signature, this paper introduces an e-payment protocol, in which customers have more initiative, and can terminate the transaction before possible cheats, its security is enhanced. Moreover, the cost of workers and communications falls down considerably while the cost of trusted authority and protecting information is increased. As there is no trusted authority in the proposed scheme, network overcrowding and conspiracy problems can be avoided. Furthermore, the protocol satisfies fairness and non-repudiation. This helps merchant and bank to speed up the financial transaction process and to give user instant services at any time. Also, in this paper, we will discuss an important e-payment protocol namely pay-word scheme and examine its advantages and limitations, which encourages the authors to improve the scheme that keeps all characteristics intact without compromise of the security robustness. The suggested protocol employs the idea of blind signature with the thought of hash chain. We will compare the proposed protocol with pay-word protocol and demonstrate that the proposed protocol offers more security and efficiency, which makes the protocol workable for real world services.

  15. A biometric signcryption scheme without bilinear pairing

    Science.gov (United States)

    Wang, Mingwen; Ren, Zhiyuan; Cai, Jun; Zheng, Wentao

    2013-03-01

    How to apply the entropy in biometrics into the encryption and remote authentication schemes to simplify the management of keys is a hot research area. Utilizing Dodis's fuzzy extractor method and Liu's original signcryption scheme, a biometric identity based signcryption scheme is proposed in this paper. The proposed scheme is more efficient than most of the previous proposed biometric signcryption schemes for that it does not need bilinear pairing computation and modular exponentiation computation which is time consuming largely. The analysis results show that under the CDH and DL hard problem assumption, the proposed scheme has the features of confidentiality and unforgeability simultaneously.

  16. Secret sharing scheme with inherited characteristic

    Institute of Scientific and Technical Information of China (English)

    Ye Zhenjun; Meng Fanzhen

    2006-01-01

    To assure the shareholders can look for their "legal" attorneys to renew the secret, once the secret sharing scheme is initialized, a secret sharing scheme with inherited characteristic is constructed. In this scheme, each shareholder can produce a new share by his algorithm, which is equivalent to the primary one. Together with other shares, the primary secret can be renewed. Since this scheme is constructed not by replacing the primary share with a new share produced by the dealer in his primitive secret sharing scheme, so no matter how much shares the shareholder produces, these shares can not be gathered together to renew the secret in this scheme. Compared with the existing secret sharing schemes, this scheme provides more agility for the shareholders by investing each of them a function but not affect its security.

  17. Ghana - Ghana Compact I Irrigation Schemes

    Data.gov (United States)

    Millennium Challenge Corporation — The Millennium Development Authority (MiDA) financed the construction of a new irrigation scheme in Kpong and the renovation of two irrigation schemes in Botanga and...

  18. Elliptic Curve Blind Digital Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    YOULin; YANGYixian; WENQiaoyan

    2003-01-01

    Blind signature schemes are important cryptographic protocols in guaranteeing the privacy or anonymity of the users.Three new blind signature schemes and their corresponding generalizations are pro-posed. Moreover, their securities are simply analyzed.

  19. Algebraic K-theory of generalized schemes

    DEFF Research Database (Denmark)

    Anevski, Stella Victoria Desiree

    Nikolai Durov has developed a generalization of conventional scheme theory in which commutative algebraic monads replace commutative unital rings as the basic algebraic objects. The resulting geometry is expressive enough to encompass conventional scheme theory, tropical algebraic geometry...

  20. Wireless Broadband Access and Accounting Schemes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we propose two wireless broadband access and accounting schemes. In both schemes, the accounting system adopts RADIUS protocol, but the access system adopts SSH and SSL protocols respectively.

  1. A massive momentum-subtraction scheme

    CERN Document Server

    Boyle, Peter; Khamseh, Ava

    2016-01-01

    A new renormalization scheme is defined for fermion bilinears in QCD at non vanishing quark masses. This new scheme, denoted RI/mSMOM, preserves the benefits of the nonexceptional momenta introduced in the RI/SMOM scheme, and allows a definition of renormalized composite fields away from the chiral limit. Some properties of the scheme are investigated by performing explicit one-loop computation in dimensional regularization.

  2. Improvement of publicly verifiable authenticated encryption scheme

    Institute of Scientific and Technical Information of China (English)

    LEI Fei-yu; CHEN Wen; MA Chang-she; CHEN Ke-fei

    2007-01-01

    A weakness of unforgeability is found in Ma and Chen scheme, and the root cause is the susceptive linear design in the scheme. In order to avoid the weakness and susceptive linear design, an improvement by means of two mechanisms including quadratic residue and composite discrete logarithm is proposed, which can defeat the forgery attacks in Ma and Chen scheme. The new scheme remains good confidentiality, public verifiability and efficiency.

  3. Linear multi-secret sharing schemes

    Institute of Scientific and Technical Information of China (English)

    XIAO Liangliang; LIU Mulan

    2005-01-01

    In this paper the linear multi-secret sharing schemes are studied by using monotone span programs. A relation between computing monotone Boolean functions by using monotone span programs and realizing multi-access structures by using linear multisecret sharing schemes is shown. Furthermore, the concept of optimal linear multi-secret sharing scheme is presented and the several schemes are proved to be optimal.

  4. MIRD radionuclide data and decay schemes

    CERN Document Server

    Eckerman, Keith F

    2007-01-01

    For all physicians, scientists, and physicists working in the nuclear medicine field, the MIRD: Radionuclide Data and Decay Schemes updated edition is an essential sourcebook for radiation dosimetry and understanding the properties of radionuclides. Includes CD Table of Contents Decay schemes listed by atomic number Radioactive decay processes Serial decay schemes Decay schemes and decay tables This essential reference for nuclear medicine physicians, scientists and physicists also includes a CD with tabulations of the radionuclide data necessary for dosimetry calculations.

  5. Comparative study of numerical schemes of TVD3, UNO3-ACM and optimized compact scheme

    Science.gov (United States)

    Lee, Duck-Joo; Hwang, Chang-Jeon; Ko, Duck-Kon; Kim, Jae-Wook

    1995-01-01

    Three different schemes are employed to solve the benchmark problem. The first one is a conventional TVD-MUSCL (Monotone Upwind Schemes for Conservation Laws) scheme. The second scheme is a UNO3-ACM (Uniformly Non-Oscillatory Artificial Compression Method) scheme. The third scheme is an optimized compact finite difference scheme modified by us: the 4th order Runge Kutta time stepping, the 4th order pentadiagonal compact spatial discretization with the maximum resolution characteristics. The problems of category 1 are solved by using the second (UNO3-ACM) and third (Optimized Compact) schemes. The problems of category 2 are solved by using the first (TVD3) and second (UNO3-ACM) schemes. The problem of category 5 is solved by using the first (TVD3) scheme. It can be concluded from the present calculations that the Optimized Compact scheme and the UN03-ACM show good resolutions for category 1 and category 2 respectively.

  6. Arbitrated quantum signature scheme with message recovery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hwayean; Hong, Changho; Kim, Hyunsang; Lim, Jongin; Yang, Hyung Jin

    2004-02-16

    Two quantum signature schemes with message recovery relying on the availability of an arbitrator are proposed. One scheme uses a public board and the other does not. However both schemes provide confidentiality of the message and a higher efficiency in transmission.

  7. Quantum Signature Scheme with Weak Arbitrator

    Science.gov (United States)

    Luo, Ming-Xing; Chen, Xiu-Bo; Yun, Deng; Yang, Yi-Xian

    2012-07-01

    In this paper, we propose one quantum signature scheme with a weak arbitrator to sign classical messages. This scheme can preserve the merits in the original arbitrated scheme with some entanglement resources, and provide a higher efficiency in transmission and reduction the complexity of implementation. The arbitrator is costless and only involved in the disagreement case.

  8. A new semi-Lagrangian difference scheme

    Institute of Scientific and Technical Information of China (English)

    季仲贞; 陈嘉滨

    2001-01-01

    A new completely energy-conserving semi-Lagrangian scheme is constructed. The numerical solution of shallow water equation shows that this conservative scheme preserves the total energy in twelve significant digits, while the traditional scheme does only in five significant digits.

  9. Population Monotonic Path Schemes for Simple Games

    NARCIS (Netherlands)

    Ciftci, B.B.; Borm, P.E.M.; Hamers, H.J.M.

    2006-01-01

    A path scheme for a simple game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path.A path scheme is called population monotonic if a player's payoff does not decrease as the pa

  10. Current terminology and diagnostic classification schemes.

    Science.gov (United States)

    Okeson, J P

    1997-01-01

    This article reviews the current terminology and classification schemes available for temporomandibular disorders. The origin of each term is presented, and the classification schemes that have been offered for temporomandibular disorders are briefly reviewed. Several important classifications are presented in more detail, with mention of advantages and disadvantages. Final recommendations are provided for future direction in the area of classification schemes.

  11. A Model of Hierarchical Key Assignment Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhigang; ZHAO Jing; XU Maozhi

    2006-01-01

    A model of the hierarchical key assignment scheme is approached in this paper, which can be used with any cryptography algorithm. Besides, the optimal dynamic control property of a hierarchical key assignment scheme will be defined in this paper. Also, our scheme model will meet this property.

  12. REMINDER: Saved Leave Scheme (SLS)

    CERN Multimedia

    2003-01-01

    Transfer of leave to saved leave accounts Under the provisions of the voluntary saved leave scheme (SLS), a maximum total of 10 days'* annual and compensatory leave (excluding saved leave accumulated in accordance with the provisions of Administrative Circular No 22B) can be transferred to the saved leave account at the end of the leave year (30 September). We remind you that unused leave of all those taking part in the saved leave scheme at the closure of the leave year accounts is transferred automatically to the saved leave account on that date. Therefore, staff members have no administrative steps to take. In addition, the transfer, which eliminates the risk of omitting to request leave transfers and rules out calculation errors in transfer requests, will be clearly shown in the list of leave transactions that can be consulted in EDH from October 2003 onwards. Furthermore, this automatic leave transfer optimizes staff members' chances of benefiting from a saved leave bonus provided that they ar...

  13. A Provably Secure Asynchronous Proactive RSA Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; LI Qiang; CHEN Ke-fei

    2005-01-01

    The drawback of the first asynchronous proactive RSA scheme presented by Zhou in 2001, is that the se curity definition and security proof do not follow the approach of provable security. This paper presented a provably secure asynchronous proactive RSA scheme, which includes three protocols: initial key distribution protocol,signature generation protocol and share refreshing protocol. Taken these protocols together, a complete provably secure proactive RSA scheme was obtained. And the efficiency of the scheme is approximate to that of the scheme of Zhou.

  14. Hash function based secret sharing scheme designs

    CERN Document Server

    Chum, Chi Sing

    2011-01-01

    Secret sharing schemes create an effective method to safeguard a secret by dividing it among several participants. By using hash functions and the herding hashes technique, we first set up a (t+1, n) threshold scheme which is perfect and ideal, and then extend it to schemes for any general access structure. The schemes can be further set up as proactive or verifiable if necessary. The setup and recovery of the secret is efficient due to the fast calculation of the hash function. The proposed scheme is flexible because of the use of existing hash functions.

  15. Modification of QUICK scheme by skew points

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaei, M.; Mohammadi, R.; Malekzadeh, M. [K.N. Toosi Univ. of Technology, Aerospace Engineering Dept., Tehran (Iran, Islamic Republic of)]. E-mail: Mirzaei@kntu.ac.ir

    2005-07-01

    This paper presents a new method for convective flux approximation based on inclusions of skew points. The scheme uses the truncated terms of QUICK scheme and with the aid of an equation extracted from momentum equations, the skew points will appear in the convective flux formula. The results show that the presented scheme has better accuracy than the other schemes. Diffusion fluxes are approximated using power law scheme and for evaluation of the performance of the presented method several test cases were carried out and the results are compared with the results of other numerical works and experimental data. (author)

  16. Pseudorandomness of Camellia-Like Scheme

    Institute of Scientific and Technical Information of China (English)

    Wen-Ling Wu

    2006-01-01

    Luby and Rackoff idealized DES by replacing each round function with one large random function. In this paper, the author idealizes Camellia by replacing each S-box with one small random function, which is named Camellialike scheme. It is then proved that five-round Camellia-like scheme is pseudorandom and eight-round Camellia-like scheme is super-pseudorandom for adaptive adversaries. Further the paper considers more efficient construction of Camellia-like scheme, and discusses how to construct pseudorandom Camellia-like scheme from less random functions.

  17. A New Signature Scheme with Shared Verification

    Institute of Scientific and Technical Information of China (English)

    JIA Xiao-yun; LUO Shou-shan; YUAN Chao-wei

    2006-01-01

    With expanding user demands, digital signature techniques are also being expanded greatly, from single signature and single verification techniques to techniques supporting multi-users. This paper presents a new digital signature scheme vith shared verification based on the fiat-shamir signature scheme. This scheme is suitable not only for digital signatures of one public key, but also for situations where multiple public keys are required. In addition, the scheme can resist all kinds of collusion, making it more practicable and safer. Additionally it is more efficient than other schemes.

  18. Colluding attacks on a group signature scheme

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Xie and Yu (2005) proposed a group signature scheme and claimed that it is the most efficient group signature scheme so far and secure. In this paper, we show that two dishonest group members can collude to launch two attacks on the scheme. In the first attack they can derive the group secret key and then generate untraceable group signatures. In the second attack, they can impersonate other group members once they see their signatures. Therefore we conclude that the signature scheme is not secure.We show that some parameters should be carefully selected in the scheme to resist our attacks.

  19. Nonrepudiable Proxy Multi-Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    LI JiGuo(李继国); CAO ZhenFu(曹珍富); ZHANG YiChen(张亦辰)

    2003-01-01

    The concept of proxy signature introduced by Mambo, Usuda, and Okamotoallows a designated person, called a proxy signer, to sign on behalf of an original signer. However,most existing proxy signature schemes do not support nonrepudiation. In this paper, two securenonrepudiable proxy multi-signature schemes are proposed that overcome disadvantages of theexisting schemes. The proposed schemes can withstand public key substitution attack. In addition,the new schemes have some other advantages such as proxy signature key generation and updatingusing insecure channels. This approach can also be applied to other ElGamal-like proxy signatureschemes.

  20. Unified Schemes for Radio-loud AGN: Recent Results

    OpenAIRE

    Padovani, Paolo

    1997-01-01

    After briefly summarizing the main tenets of unified schemes of Active Galactic Nuclei, I review some recent results in the field of unification of radio-loud sources, both for the low-luminosity (BL Lacs and Fanaroff-Riley type I radio galaxies) and high-luminosity (radio quasars and Fanaroff-Riley type II radio galaxies) populations.

  1. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten;

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap-abl...

  2. High-Order Energy Stable WENO Schemes

    Science.gov (United States)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2008-01-01

    A new third-order Energy Stable Weighted Essentially NonOscillatory (ESWENO) finite difference scheme for scalar and vector linear hyperbolic equations with piecewise continuous initial conditions is developed. The new scheme is proven to be stable in the energy norm for both continuous and discontinuous solutions. In contrast to the existing high-resolution shock-capturing schemes, no assumption that the reconstruction should be total variation bounded (TVB) is explicitly required to prove stability of the new scheme. A rigorous truncation error analysis is presented showing that the accuracy of the 3rd-order ESWENO scheme is drastically improved if the tuning parameters of the weight functions satisfy certain criteria. Numerical results show that the new ESWENO scheme is stable and significantly outperforms the conventional third-order WENO finite difference scheme of Jiang and Shu in terms of accuracy, while providing essentially nonoscillatory solutions near strong discontinuities.

  3. Hybrid Transmission Scheme for MIMO Relay Channels

    Directory of Open Access Journals (Sweden)

    Guangming Xu

    2009-11-01

    Full Text Available To improve the achievable rate for the MIMO channels, we propose a hybrid transmission (HT scheme that mixes half-duplex decode-and-forward cooperative relaying transmission (DFRH)with direct transmission (DT. In the HT scheme, the source message is divided into two parts: one is transmitted by DFRH scheme and another is transmitted by DT scheme. Precoding and decoding are considered to convert the original MIMO relay channel into several parallel subchannels so that resource allocation can be easily performed. We focus on the spatial subchannel and power allocation problem. The objective of this problem is to maximize the total achievable rate under the constraints of joint total transmission power. Simulation results show that significant capacity gain can be achieved by the HT scheme compared to the DT scheme and the pure DFRH scheme.

  4. A New Proxy Signature Scheme with Message Recovery Using Self-Certified Public Key

    Institute of Scientific and Technical Information of China (English)

    LI Ji-guo; ZHANG Yi-chen; ZHU Yue-long

    2005-01-01

    A proxy signature scheme with message recovery using self-certified public key is proposed, which withstands public key substitution attacks, active attacks, and forgery attacks. The proposed scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, the proposed scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signature signer.

  5. A NEW ANONYMITY CONTROLLED E-CASH SCHEME

    Institute of Scientific and Technical Information of China (English)

    Zhang Fangguo; Wang Changjie; Wang Yumin

    2002-01-01

    E-cash is a type of very important electronic payment systems. The complete anonymity of E-cash can be used for criminal activities, so E-cash should be anonymity controlled.Moreover, Elliptic Curve Cryptography(ECC) has been regard as the mainstream of current public cryptography . In this paper, a new anonymity controlled E-cash scheme based on ECC for the first time and using a new technology-one-time key pairs digital signature is designed, and its security and efficiency are analyzed. In our scheme, the coin tracing and owner tracing can be implemented.

  6. Fragment separator momentum compression schemes

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, Laura, E-mail: bandura@anl.gov [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Erdelyi, Bela [Argonne National Laboratory, Argonne, IL 60439 (United States); Northern Illinois University, DeKalb, IL 60115 (United States); Hausmann, Marc [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Kubo, Toshiyuki [RIKEN Nishina Center, RIKEN, Wako (Japan); Nolen, Jerry [Argonne National Laboratory, Argonne, IL 60439 (United States); Portillo, Mauricio [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Sherrill, Bradley M. [National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States)

    2011-07-21

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  7. Fragment separator momentum compression schemes.

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, L.; Erdelyi, B.; Hausmann, M.; Kubo, T.; Nolen, J.; Portillo, M.; Sherrill, B.M. (Physics); (MSU); (Northern Illinois Univ.); (RIKEN)

    2011-07-21

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  8. Network Regulation and Support Schemes

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Schröder, Sascha Thorsten; Jacobsen, Henrik

    2009-01-01

    -in tariffs to market-based quota systems, and network regulation approaches, comprising rate-of-return and incentive regulation. National regulation and the vertical structure of the electricity sector shape the incentives of market agents, notably of distributed generators and network operators....... This article seeks to investigate the interactions between the policy dimensions of support schemes and network regulation and how they affect the deployment of distributed generation. Firstly, a conceptual analysis examines how the incentives of the different market agents are affected. In particular......, it will be shown that there frequently exists a trade-off between the creation of incentives for distributed generators and for distribution system operators to facilitate the integration of distributed generation. Secondly, the interaction of these policy dimensions is analyzed, including case studies based...

  9. Control Scheme for Distributed Generator Providing Network Voltage Support

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The distributed generator over the last 30 years has posed several challenges when they are connected to a distributed network. The most immediate problem is to change the voltage at the connection point depending on the power supplied to the network and may cause it to exceed statutory limits. This paper describes a new control scheme for a distributed generator for supporting the voltage control in the network, thus ensuring the distributed generator to contribute to network voltage management. The scheme performance is demonstrated by a model for a distributed generator connected to a distribution network. The result shows that using the new control scheme, the distribution network voltage constraints are maintained while maximizing the active power delivered by distributed generators.

  10. Improvement of Some Proxy Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    LIJiguo; LIANGZhenghe; ZHUYuelong; HANGYichen

    2005-01-01

    In 1996, Mambo et al. introduced the concept of proxy signature. Proxy signature can be applied to mobile agent, e-vote etc. Recently, Sun and Hsieh showed that Lee et al's strong proxy signature scheme and its application to multi-proxy signature scheme, Shum and Wei's privacy-protected strong proxy signature scheme, and Park and Lee's nominative proxy signature scheme were all insecure against the original signer's forgery attack. In this paper, we show those proxy signature schemes don't withstand public key substitution attack and give some slight but important modifications for those proxy signature schemes such that the resulting schemes are secure against the original signer's forgery attack and public key substitution attack. In addition, we show that Park and Lee's nominative proxy signature scheme don't satisfy strong nonrepudiation and strong identifiability. Improved schemes satisfy all properties of strong proxy signature scheme, and doesn't use secure channel between the original signer and the proxy signer.

  11. Meal box schemes a convenient way to avoid convenience food? Uses and understandings of meal box schemes among Danish consumers.

    Science.gov (United States)

    Hertz, Frej Daniel; Halkier, Bente

    2017-03-15

    The term convenience food is subject to diversification, lack of clarity and moral ambiguity. In this paper we address these issues and critically discuss convenience food by using empirical findings from a Danish study that deals with practitioners' uses of meal box schemes. The methodological design consists of thirteen individual interviews, four focus groups and some observations of cooking practices. We combine the empirical findings with a particular definition of convenience food by Brunner et al. (2010) and selected practice theoretical concepts. This particular combination enables us to categorize meal box schemes as a new form of convenience food called convenient food. In addition, results suggest that meal box schemes reduce leftovers from dinner. Meal boxes also influence dinner related activities such as planning ahead in time and grocery shopping, which require less physical and mental effort.

  12. On the security of two remote user authentication schemes for telecare medical information systems.

    Science.gov (United States)

    Kim, Kee-Won; Lee, Jae-Dong

    2014-05-01

    The telecare medical information systems (TMISs) support convenient and rapid health-care services. A secure and efficient authentication scheme for TMIS provides safeguarding patients' electronic patient records (EPRs) and helps health care workers and medical personnel to rapidly making correct clinical decisions. Recently, Kumari et al. proposed a password based user authentication scheme using smart cards for TMIS, and claimed that the proposed scheme could resist various malicious attacks. However, we point out that their scheme is still vulnerable to lost smart card and cannot provide forward secrecy. Subsequently, Das and Goswami proposed a secure and efficient uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care. They simulated their scheme for the formal security verification using the widely-accepted automated validation of Internet security protocols and applications (AVISPA) tool to ensure that their scheme is secure against passive and active attacks. However, we show that their scheme is still vulnerable to smart card loss attacks and cannot provide forward secrecy property. The proposed cryptanalysis discourages any use of the two schemes under investigation in practice and reveals some subtleties and challenges in designing this type of schemes.

  13. Setting aside Transactions from Pyramid Schemes as Impeachable Dispositions under South African Insolvency Legislation

    Directory of Open Access Journals (Sweden)

    Zingapi Mabe

    2016-10-01

    Full Text Available South African courts have experienced a rise in the number of cases involving schemes that promise a return on investment with interest rates which are considerably above the maximum amount allowed by law, or schemes which promise compensation from the active recruitment of participants. These schemes, which are often referred to as pyramid or Ponzi schemes, are unsustainable operations and give rise to problems in the law of insolvency. Investors in these schemes are often left empty-handed upon the scheme’s eventual collapse and insolvency. Investors who received pay-outs from the scheme find themselves in the defence against the trustee’s claims for the return of the pay-outs to the insolvent estate. As the schemes are illegal and the pay-outs are often in terms of void agreements, the question arises whether they can be returned to the insolvent estate. A similar situation arose in Griffiths v Janse van Rensburg 2015 ZASCA 158 (26 October 2015. The point of contention in this case was whether the illegality of the business of the scheme was a relevant consideration in determining whether the pay-outs were made in the ordinary course of business of the scheme. This paper discusses pyramid schemes in the context of impeachable dispositions in terms of the Insolvency Act 24 of 1936.

  14. Space Vector Pulse Width Modulation Scheme for a Seven-Phase Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Mohd. Arif Khan

    2011-09-01

    Full Text Available This paper analyses a simple space vector PWM (SVPWM scheme for a seven-phase voltage source inverter. At first the conventional method of producing sinusoidal output voltage  by utilizing six active and a zero space vectors are used to synthesis the input reference and then new PWM scheme called time equivalent space vector PWM is presented.  A comparison of the proposed scheme with the conventional scheme is presented based on various performance indices. Extensive Simulation results are provided to validate the findings

  15. Rapid Parameterization Schemes for Aircraft Shape Optimization

    Science.gov (United States)

    Li, Wu

    2012-01-01

    A rapid shape parameterization tool called PROTEUS is developed for aircraft shape optimization. This tool can be applied directly to any aircraft geometry that has been defined in PLOT3D format, with the restriction that each aircraft component must be defined by only one data block. PROTEUS has eight types of parameterization schemes: planform, wing surface, twist, body surface, body scaling, body camber line, shifting/scaling, and linear morphing. These parametric schemes can be applied to two types of components: wing-type surfaces (e.g., wing, canard, horizontal tail, vertical tail, and pylon) and body-type surfaces (e.g., fuselage, pod, and nacelle). These schemes permit the easy setup of commonly used shape modification methods, and each customized parametric scheme can be applied to the same type of component for any configuration. This paper explains the mathematics for these parametric schemes and uses two supersonic configurations to demonstrate the application of these schemes.

  16. On Optimal Designs of Some Censoring Schemes

    Directory of Open Access Journals (Sweden)

    Dr. Adnan Mohammad Awad

    2016-03-01

    Full Text Available The main objective of this paper  is to explore suitability of some entropy-information measures for introducing a new optimality censoring criterion and to apply it to some censoring schemes from some underlying life-time models.  In addition, the  paper investigates four related issues namely; the  effect of the parameter of parent distribution on optimal scheme, equivalence of schemes based on Shannon and Awad sup-entropy measures, the conjecture that the optimal scheme is one stage scheme, and  a conjecture by Cramer and Bagh (2011 about Shannon minimum and maximum schemes when parent distribution is reflected power. Guidelines for designing an optimal censoring plane are reported together with theoretical and numerical results and illustrations.

  17. A Signature Scheme with Non-Repudiation

    Institute of Scientific and Technical Information of China (English)

    XIN Xiangjun; GUO Xiaoli; XIAO Guozhen

    2006-01-01

    Based on the Schnorr signature scheme, a new signature scheme with non-repudiation is proposed. In this scheme, only the signer and the designated receiver can verify the signature signed by the signer, and if necessary, both the signer and the designated receiver can prove and show the validity of the signature signed by the signer. The proof of the validity of the signature is noninteractive and transferable. To verify and prove the validity of the signature, the signer and the nominated receiver needn't store extra information besides the signature. At the same time, neither the signer nor the designated receiver can deny a valid signature signed. Then, there is no repudiation in this new signature scheme. According to the security analysis of this scheme, it is found the proposed scheme is secure against existential forgery on adaptive chosen message attack.

  18. Incorporating Partner Practice and Writing and Self-Regulation into the Theme Scheme Program.

    Science.gov (United States)

    Williams, Joanna P.

    2003-01-01

    This article discusses activities developed for the "Theme Scheme," an instructional program for elementary and middle school children at risk for failure. "Theme Scheme" is a listening and reading comprehension program that uses peer-assisted learning strategies and writing exercises to teach students to understand text at an abstract,…

  19. Resonance ionization scheme development for europium

    CERN Document Server

    Chrysalidis, K; Fedosseev, V N; Marsh, B A; Naubereit, P; Rothe, S; Seiffert, C; Kron, T; Wendt, K

    2017-01-01

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  20. Blind Signature Scheme Based on Chebyshev Polynomials

    OpenAIRE

    Maheswara Rao Valluri

    2011-01-01

    A blind signature scheme is a cryptographic protocol to obtain a valid signature for a message from a signer such that signer’s view of the protocol can’t be linked to the resulting message signature pair. This paper presents blind signature scheme using Chebyshev polynomials. The security of the given scheme depends upon the intractability of the integer factorization problem and discrete logarithms ofChebyshev polynomials.

  1. Blind Signature Scheme Based on Chebyshev Polynomials

    Directory of Open Access Journals (Sweden)

    Maheswara Rao Valluri

    2011-12-01

    Full Text Available A blind signature scheme is a cryptographic protocol to obtain a valid signature for a message from a signer such that signer’s view of the protocol can’t be linked to the resulting message signature pair. This paper presents blind signature scheme using Chebyshev polynomials. The security of the given scheme depends upon the intractability of the integer factorization problem and discrete logarithms ofChebyshev polynomials.

  2. Multi-object quantum traveling ballot scheme

    Institute of Scientific and Technical Information of China (English)

    Yuan Li; Guihua Zeng

    2009-01-01

    Based on quantum mechanics, a traveling ballot scheme with anonymity and secrecy is introduced to realize voting. By searching the objects in large amount of data bases, every voter may cast votes to his desired candidates. Therefore, the proposed scheme may be applied to voting with a great deal of candidates, such as network voting and so on. The security analysis of the present scheme is also performed.

  3. General Compact Labeling Schemes for Dynamic Trees

    OpenAIRE

    2006-01-01

    Let $F$ be a function on pairs of vertices. An {\\em $F$- labeling scheme} is composed of a {\\em marker} algorithm for labeling the vertices of a graph with short labels, coupled with a {\\em decoder} algorithm allowing one to compute $F(u,v)$ of any two vertices $u$ and $v$ directly from their labels. As applications for labeling schemes concern mainly large and dynamically changing networks, it is of interest to study {\\em distributed dynamic} labeling schemes. This paper investigates labelin...

  4. Signcryption scheme based on schnorr digital signature

    CERN Document Server

    Savu, Laura

    2012-01-01

    This article presents a new signcryption scheme which is based on the Schnorr digital signature algorithm. The new scheme represents my personal contribution to signcryption area. I have been implemented the algorithm in a program and here are provided the steps of the algorithm, the results and some examples. The paper also contains the presentation of the original Signcryption scheme, based on ElGamal digital signature and discusses the practical applications of Signcryption in real life.

  5. SYNCHRONIZATION RECOVERY SCHEME IN WATERMARKING DETECTION

    Institute of Scientific and Technical Information of China (English)

    Xiao Weiwei; Zhang Li; Ji Zhen; Zhang Jihong

    2003-01-01

    Most proposed digital watermarking algorithms are sensitive to geometric attacksbecause the synchronization information of watermark embedding and detection is destroyed. Inthis letter a novel synchronization recovery scheme based on image normalization is proposed. Thepresented scheme does not require the original image and can be applied to various watermarksystems. A wavelet-based watermarking scheme is proposed as an example and experimentalresults show that it is robust to geometric attacks.

  6. Efficient Certificateless Signcryption Scheme from Weil Pairing

    Directory of Open Access Journals (Sweden)

    Gang Yu

    2011-08-01

    Full Text Available Certificateless signcryption has both the advantage of certificateless public key cryptography, which overcome the escrow problem inherited from identity based cryptography without the use of certificates as in traditional public key cryptography, and signcryption which can fulfill both the functions of signature and encryption in a logical signal step. In this paper, we explicit the security model for certificateless signcryption and propose an efficient certificateless signcryption scheme from Weil pairings. The new scheme not only can be proved to be secure in our model but also can simultaneously provide public verifiability and forward security. Furthermore, compared with existing schemes, the new scheme is more efficient.

  7. Optimizing Decision Tree Attack on CAS Scheme

    Directory of Open Access Journals (Sweden)

    PERKOVIC, T.

    2016-05-01

    Full Text Available In this paper we show a successful side-channel timing attack on a well-known high-complexity cognitive authentication (CAS scheme. We exploit the weakness of CAS scheme that comes from the asymmetry of the virtual interface and graphical layout which results in nonuniform human behavior during the login procedure, leading to detectable variations in user's response times. We optimized a well-known probabilistic decision tree attack on CAS scheme by introducing this timing information into the attack. We show that the developed classifier could be used to significantly reduce the number of login sessions required to break the CAS scheme.

  8. A new access scheme in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    GU Xue-lin; YAN Wei; TIAN Hui; ZHANG Ping

    2006-01-01

    This article presents a dynamic random access scheme for orthogonal frequency division multiple access (OFDMA) systems. The key features of the proposed scheme are:it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes,and it can adjust the number of random access channels in a media access control (MAC) frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.

  9. An Improved Proxy Multi-Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    GU Li-ze; ZHANG Sheng; YANG Yi-xian

    2005-01-01

    Based on the Kim-like's proxy multi-signature scheme[1],an improved proxy multi-signature scheme is proposed.The new scheme overcomes the two problems in the Kim-like's proxy multi-signature scheme:(1)Security issue(every original signer can forge a valid proxy multi-signature for any message);(2)Efficiency issue(both the size of the proxy multi-signature and the efficiency of signature checking are dependent on the number of the original signers).

  10. Sampling scheme optimization from hyperspectral data

    NARCIS (Netherlands)

    Debba, P.

    2006-01-01

    This thesis presents statistical sampling scheme optimization for geo-environ-menta] purposes on the basis of hyperspectral data. It integrates derived products of the hyperspectral remote sensing data into individual sampling schemes. Five different issues are being dealt with.First, the optimized

  11. Modified Mean-Pyramid Coding Scheme

    Science.gov (United States)

    Cheung, Kar-Ming; Romer, Richard

    1996-01-01

    Modified mean-pyramid coding scheme requires transmission of slightly fewer data. Data-expansion factor reduced from 1/3 to 1/12. Schemes for progressive transmission of image data transmitted in sequence of frames in such way coarse version of image reconstructed after receipt of first frame and increasingly refined version of image reconstructed after receipt of each subsequent frame.

  12. Nonstandard finite difference schemes for differential equations

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdizadeh Khalsaraei

    2014-12-01

    Full Text Available In this paper, the reorganization of the denominator of the discrete derivative and nonlocal approximation of nonlinear terms are used in the design of nonstandard finite difference schemes (NSFDs. Numerical examples confirming then efficiency of schemes, for some differential equations are provided. In order to illustrate the accuracy of the new NSFDs, the numerical results are compared with standard methods.

  13. Unconditionnally stable scheme for Riccati equation

    CERN Document Server

    Dubois, François; 10.1051/proc:2000003

    2011-01-01

    We present a numerical scheme for the resolution of matrix Riccati equation used in control problems. The scheme is unconditionnally stable and the solution is definite positive at each time step of the resolution. We prove the convergence in the scalar case and present several numerical experiments for classical test cases.

  14. Consolidation of the health insurance scheme

    CERN Multimedia

    Association du personnel

    2009-01-01

    In the last issue of Echo, we highlighted CERN’s obligation to guarantee a social security scheme for all employees, pensioners and their families. In that issue we talked about the first component: pensions. This time we shall discuss the other component: the CERN Health Insurance Scheme (CHIS).

  15. Privacy Preserving Mapping Schemes Supporting Comparison

    NARCIS (Netherlands)

    Tang, Qiang

    2010-01-01

    To cater to the privacy requirements in cloud computing, we introduce a new primitive, namely Privacy Preserving Mapping (PPM) schemes supporting comparison. An PPM scheme enables a user to map data items into images in such a way that, with a set of images, any entity can determine the $<, =, >$ re

  16. Novel Link Adaptation Schemes for OFDM System

    Institute of Scientific and Technical Information of China (English)

    LEI Ming; CAI Peng; XU Yue-shan; ZHANG Ping

    2003-01-01

    Orthogonal Frequency Division Multiplexing (OFDM) is the most promising technique supporting the high data rate transmission. The combination of the link adaptation and OFDM can further increase the spectral efficiency. In this paper, we put forward two link adaptation schemes for OFDM system which have the advantages of both flexibility and practicability. Both of the two novel link adaptation schemes are based on the iterative mechanism to allocate the bit and power to subcarriers according to their channel gains and noisy levels which are assumed to be already known at the transmitter. The candidate modulation modes are determined freely before the link adaptation schemes are performed. The distinction between the two novel link adaptation schemes is that in the novel scheme A, the modulation mode is upgraded to the neighboring higher-order mode, while in the novel scheme B the modulation is upgraded to the genuine optimal mode. Therefore, the novel scheme A has the advantage of lower complexity and the novel scheme B has the advantage of higher spectral efficiency.

  17. Phase calibration scheme for a ``T'' array

    Science.gov (United States)

    Ramesh, R.; Subramanian, K. R.; Sastry, Ch. V.

    1999-10-01

    A calibration scheme based on closure and redundancy techniques is described for correcting the phase errors in the complex visibilities observed with a T-shaped radio interferometer array. Practical details of the scheme are illustrated with reference to the Gauribidanur radioheliograph (GRH).

  18. Hybrid scheme for Brownian semistationary processes

    DEFF Research Database (Denmark)

    Bennedsen, Mikkel; Lunde, Asger; Pakkanen, Mikko S.

    We introduce a simulation scheme for Brownian semistationary processes, which is based on discretizing the stochastic integral representation of the process in the time domain. We assume that the kernel function of the process is regularly varying at zero. The novel feature of the scheme is to ap...

  19. A New Public-Key Encryption Scheme

    Institute of Scientific and Technical Information of China (English)

    Hai-Bo Tian; Xi Sun; Yu-Min Wang

    2007-01-01

    This paper proposes a new public-key encryption scheme which removes one element from the public-key tuple of the original Cramer-Shoup scheme.As a result, a ciphertext is not a quadruple but a triple at the cost of a strong assumption,the third version of knowledge of exponent assumption (KEA3).Under assumptions of KEA3, a decision Diffie-Hellman (DDH) and a variant of target collision resistance (TCRv), the new scheme is proved secure against indistinguishable adaptive chosen ciphertext attack (IND-CCA2).This scheme is as efficient as Damgard ElGamal (DEG) scheme when it makes use of a well-known algorithm for product of exponentiations.The DEG scheme is recently proved IND-CCA1 secure by Bellare and Palacio in ASIACRYPT 2004 under another strong assumption.In addition to our IND-CCA2 secured scheme, we also believe that the security proof procedure itself provides a well insight for ElGamal-based encryption schemes which are secure in real world.

  20. Mixed ultrasoft/norm-conserved pseudopotential scheme

    DEFF Research Database (Denmark)

    Stokbro, Kurt

    1996-01-01

    A variant of the Vanderbilt ultrasoft pseudopotential scheme, where the norm conservation is released for only one or a few angular channels, is presented. Within this scheme some difficulties of the truly ultrasoft pseudopotentials are overcome without sacrificing the pseudopotential softness. (...

  1. Anonymous Credential Schemes with Encrypted Attributes

    NARCIS (Netherlands)

    Guajardo Merchan, J.; Mennink, B.; Schoenmakers, B.

    2011-01-01

    In anonymous credential schemes, users obtain credentials on certain attributes from an issuer, and later show these credentials to a relying party anonymously and without fully disclosing the attributes. In this paper, we introduce the notion of (anonymous) credential schemes with encrypted attribu

  2. Cornering (3+1) sterile neutrino schemes

    CERN Document Server

    Maltoni, M; Valle, José W F

    2001-01-01

    Using the most recent atmospheric neutrino data, as well as short-baseline and tritium $\\beta$-decay data we show that (3+1) sterile neutrino schemes are severely disfavored, in contrast to the theoretically favored (2+2) schemes.

  3. A Secure Threshold Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaoming; Fu Fangwei

    2003-01-01

    The threshold group signature is an important kind of signature. So far, many threshold group signature schemes have been proposed, but most of them suffer from conspiracy attack and are insecure. In this paper, a secure threshold group signature scheme is proposed. It can not only satisfy the properties of the threshold group signature, but also withstand the conspiracy attack

  4. Modeling Students' Mathematics Using Steffe's Fraction Schemes

    Science.gov (United States)

    Norton, Anderson H.; McCloskey, Andrea V.

    2008-01-01

    Each year, more teachers learn about the successful intervention program known as Math Recovery (USMRC 2008; Wright 2003). The program uses Steffe's whole-number schemes to model, understand, and support children's development of whole-number reasoning. Readers are probably less familiar with Steffe's fraction schemes, which have proven similarly…

  5. An Efficient Forward Secure Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    YU Jia; KONG Fan-yu; LI Da-xing

    2006-01-01

    A new efficient forward secure signature scheme based on bilinear pairings is presented in this paper.Each complexity of key generation, key update, signing and verifying algorithms in this scheme is O(1) in terms of the total number of time periods T. Because a new structure in node secret key storage and a unique strategy in key update are employed, the signing and verifying costs don't grow when T increases. At the same time, the key generation and key update algorithms are efficiently constructed thanks to using the pre-order traversal technique of binary trees. Compared with other schemes based on bilinear pairings, the signature size in this scheme is very short, which doesn't change with T increasing. The scheme is forward secure in random oracle model assuming CDH problem is hard.

  6. A DRM Scheme Using File Physical Information

    Directory of Open Access Journals (Sweden)

    Cheng Qu

    2015-05-01

    Full Text Available A digital file has both the content and physical information, however the latter was not fully made use of in previous digital rights management (DRM systems. This paper introduces the idea of making use of file physical information to improve the system security and provides a scheme based on this idea to resist the replay attack in DRM systems. In our scheme, compared to commonly used schemes, we remove the dependency on continuous online connection from the client-side to the server-side or the usage of tamper-proof hardware, such as Trusted Platform Module (TPM. The scheme is appropriate for offline digital content usage. Primary experiments demonstrate that our scheme is secure enough to be put into practice use.

  7. Two level scheme solvers for nuclear spectroscopy

    Science.gov (United States)

    Jansson, Kaj; DiJulio, Douglas; Cederkäll, Joakim

    2011-10-01

    A program for building level schemes from γ-spectroscopy coincidence data has been developed. The scheme builder was equipped with two different algorithms: a statistical one based on the Metropolis method and a more logical one, called REMP (REcurse, Merge and Permute), developed from scratch. These two methods are compared both on ideal cases and on experimental γ-ray data sets. The REMP algorithm is based on coincidences and transition energies. Using correct and complete coincidence data, it has solved approximately half a million schemes without failures. Also, for incomplete data and data with minor errors, the algorithm produces consistent sub-schemes when it is not possible to obtain a complete scheme from the provided data.

  8. Autonomous droop scheme with reduced generation cost

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Droop scheme has been widely applied to the control of Distributed Generators (DGs) in microgrids for proportional power sharing based on their ratings. For standalone microgrid, where centralized management system is not viable, the proportional power sharing based droop might not suit well since...... DGs are usually of different types unlike synchronous generators. This paper presents an autonomous droop scheme that takes into consideration the operating cost, efficiency and emission penalty of each DG since all these factors directly or indirectly contributes to the Total Generation Cost (TGC......) of the overall microgrid. Comparing it with the traditional scheme, the proposed scheme has retained its simplicity, which certainly is a feature preferred by the industry. The overall performance of the proposed scheme has been verified through simulation and experiment....

  9. Comparison among sea surface roughness schemes

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the measurements from the US National Data Buoy Center 3-m discus buoy site No.44004 (38.5°N, 70.47°W) from January 1 to March 31 of 2003, with the COARE algorithm (Version 3.0), the results from four parameterization schemes developed recently for sea surface aerodynamic roughness length were compared with each other. Calculations of frictional speed u*, drag coefficient Cd and wind stress τ indicate that the calculated frictional velocities from the four schemes (8.50%-16.20%, the normalized standard error estimate, or NSEE), the computed drag coefficients and wind stress (respectively 15.08%-28.67% and 17.26%-50.59% NSEE) are reasonable. Schemes YT96 and GW03 are consistent. The O02 scheme gives overestimated values for u* and Cd. Schemes TY01 and GW03 display discontinuous characteristics in handling young wave data.

  10. A novel key management scheme using biometrics

    Science.gov (United States)

    Sui, Yan; Yang, Kai; Du, Yingzi; Orr, Scott; Zou, Xukai

    2010-04-01

    Key management is one of the most important issues in cryptographic systems. Several important challenges in such a context are represented by secure and efficient key generation, key distribution, as well as key revocation. Addressing such challenges requires a comprehensive solution which is robust, secure and efficient. Compared to traditional key management schemes, key management using biometrics requires the presence of the user, which can reduce fraud and protect the key better. In this paper, we propose a novel key management scheme using iris based biometrics. Our newly proposed scheme outperforms traditional key management schemes as well as some existing key-binding biometric schemes in terms of security, diversity and/or efficiency.

  11. An Efficient and Practical Smart Card Based Anonymity Preserving User Authentication Scheme for TMIS using Elliptic Curve Cryptography.

    Science.gov (United States)

    Amin, Ruhul; Islam, S K Hafizul; Biswas, G P; Khan, Muhammad Khurram; Kumar, Neeraj

    2015-11-01

    In the last few years, numerous remote user authentication and session key agreement schemes have been put forwarded for Telecare Medical Information System, where the patient and medical server exchange medical information using Internet. We have found that most of the schemes are not usable for practical applications due to known security weaknesses. It is also worth to note that unrestricted number of patients login to the single medical server across the globe. Therefore, the computation and maintenance overhead would be high and the server may fail to provide services. In this article, we have designed a medical system architecture and a standard mutual authentication scheme for single medical server, where the patient can securely exchange medical data with the doctor(s) via trusted central medical server over any insecure network. We then explored the security of the scheme with its resilience to attacks. Moreover, we formally validated the proposed scheme through the simulation using Automated Validation of Internet Security Schemes and Applications software whose outcomes confirm that the scheme is protected against active and passive attacks. The performance comparison demonstrated that the proposed scheme has lower communication cost than the existing schemes in literature. In addition, the computation cost of the proposed scheme is nearly equal to the exiting schemes. The proposed scheme not only efficient in terms of different security attacks, but it also provides an efficient login, mutual authentication, session key agreement and verification and password update phases along with password recovery.

  12. Simulation study on the efficiencies of MOET nucleus breeding schemes applying marker assisted selection in dairy cattle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Advantages of breeding schemes using genetic marker information and/or multiple ovulation and embryo transfer(MOET) technology over the traditional approach were extensively evaluated through simulation.Milk yield was the trait of interest and QTL was the genetic marker utilized.Eight dairy cattle breeding scenarios were considered,i.e.,traditional progeny testing breeding scheme(denoted as STANPT),GASPT scheme including a pre-selection of young bulls entering progeny testing based on their own QTL information,MOETPT scheme using MOET technology to generate young bulls and a selection of young bulls limited within the full-sib family,GAMOPT scheme adopting both QTL pre-selection and MOET technology,COMBPT scheme using a mixed linear model which considered QTL genotype instead of the BLUP model in GAMOPT,and three non-progeny testing schemes,i.e.the MOET,GAMO and COMB schemes,corresponding to MOETPT,GAMOPT and COMBPT with progeny testing being part of the system.Animals were selected based on their breeding value which was estimated under an animal model framework.Sequential selection over 17 years was performed in the simulations and 30 replicates were designed for each scenario.The influences of using QTL information and MOET technology on favorable QTL allele frequency,true breeding values,polygenetic breeding values and the accumulated genetic superiority were extensively evaluated,for five different populations including active sires,lactating cows,bull dams,bull sires,and young bulls.The results showed that the combined schemes significantly outperformed other approaches wherein accumulated true breeding value progressed.The difference between schemes exclusively using QTL information or MOET technology was not significant.The STANPT scheme was the least efficient among the 8 schemes.The schemes using MOET technology had a higher polygenetic response than others in the 17th year.The increases of frequency of the favorable QTL allele varied more greatly across

  13. Simulation study on the efficiencies of MOET nucleus breeding schemes applying marker assisted selection in dairy cattle

    Institute of Scientific and Technical Information of China (English)

    LUO WeiZhen; WANG YaChun; ZHANG Yuan

    2009-01-01

    Advantages of breeding schemes using genetic marker information and/or multiple ovulation and em-bryo transfer (MOET) technology over the traditional approach were extensively evaluated through simulation. Milk yield was the trait of interest and QTL was the genetic marker utilized. Eight dairy cattle breeding scenarios were considered, i.e., traditional progeny testing breeding scheme (denoted as STANPT), GASPT scheme including a pre-selection of young bulls entering progeny testing based on their own QTL information, MOETPT scheme using MOET technology to generate young bulls and a selection of young bulls limited within the full-sib family, GAMOPT scheme adopting both QTL pre-selection and MOET technology, COMBPT scheme using a mixed linear model which considered QTL genotype instead of the BLUP model in GAMOPT, and three non-progeny testing schemes, i.e. the MOET, GAMO and COMB schemes, corresponding to MOETPT, GAMOPT and COMBPT with progeny testing being part of the system. Animals were selected based on their breeding value which was es-timated under an animal model framework. Sequential selection over 17 years was performed in the simulations and 30 replicates were designed for each scenario. The influences of using QTL informa-tion and MOET technology on favorable QTL allele frequency, true breeding values, polygenetic breeding values and the accumulated genetic superiority were extensively evaluated, for five different populations including active sires, lactating cows, bull dams, bull sires, and young bulls. The results showed that the combined schemes significantly outperformed other approaches wherein accumulated true breeding value progressed. The difference between schemes exclusively using QTL information or MOET technology was not significant. The STANPT scheme was the least efficient among the 8 schemes. The schemes using MOET technology had a higher polygenetic response than others in the 17th year. The increases of frequency of the favorable QTL

  14. Secure Electronic Cash Scheme with Anonymity Revocation

    Directory of Open Access Journals (Sweden)

    Baoyuan Kang

    2016-01-01

    Full Text Available In a popular electronic cash scheme, there are three participants: the bank, the customer, and the merchant. First, a customer opens an account in a bank. Then, he withdraws an e-cash from his account and pays it to a merchant. After checking the electronic cash’s validity, the merchant accepts it and deposits it to the bank. There are a number of requirements for an electronic cash scheme, such as, anonymity, unforgeability, unreusability, divisibility, transferability, and portability. Anonymity property of electronic cash schemes can ensure the privacy of payers. However, this anonymity property is easily abused by criminals. In 2011, Chen et al. proposed a novel electronic cash system with trustee-based anonymity revocation from pairing. On demand, the trustee can disclose the identity for e-cash. But, in this paper we point out that Chen et al.’s scheme is subjected to some drawbacks. To contribute secure electronic cash schemes, we propose a new offline electronic cash scheme with anonymity revocation. We also provide the formally security proofs of the unlinkability and unforgeability. Furthermore, the proposed scheme ensures the property of avoiding merchant frauds.

  15. Different options for noble gas categorization schemes

    Science.gov (United States)

    Kalinowski, Martin

    2010-05-01

    For noble gas monitoring it is crucial to support the decision makers who need to decide whether a decection may indicate a potential nuclear test. Several parameters are available that may help to distinguish a legitimate civilian source from a nuclear explosion. The most promising parameters are: (a) Anomaly observations with respect to the history of concentrations found at that site. (b) Isotopic activity ratios can be used to separate a nuclear reactor domain from the parameter space that is specific for nuclear explosions. (c) Correlation with source-receptor-sensitivities related to known civilian sources as determined by atmospheric transport simulations. A combination of these can be used to categorize an observation. So far, several initial ideas have been presented but the issue of noble gas categorisation has been postponed with the argument that further scientific studies and additional experience have to be awaited. This paper presents the principles of different options for noble gas categorisation and considers how they would meet the interests of different classes of member states. It discusses under different points of view what might be the best approach for the noble gas categorisation scheme.

  16. Testing hydrodynamics schemes in galaxy disc simulations

    Science.gov (United States)

    Few, C. G.; Dobbs, C.; Pettitt, A.; Konstandin, L.

    2016-08-01

    We examine how three fundamentally different numerical hydrodynamics codes follow the evolution of an isothermal galactic disc with an external spiral potential. We compare an adaptive mesh refinement code (RAMSES), a smoothed particle hydrodynamics code (SPHNG), and a volume-discretized mesh-less code (GIZMO). Using standard refinement criteria, we find that RAMSES produces a disc that is less vertically concentrated and does not reach such high densities as the SPHNG or GIZMO runs. The gas surface density in the spiral arms increases at a lower rate for the RAMSES simulations compared to the other codes. There is also a greater degree of substructure in the SPHNG and GIZMO runs and secondary spiral arms are more pronounced. By resolving the Jeans length with a greater number of grid cells, we achieve more similar results to the Lagrangian codes used in this study. Other alterations to the refinement scheme (adding extra levels of refinement and refining based on local density gradients) are less successful in reducing the disparity between RAMSES and SPHNG/GIZMO. Although more similar, SPHNG displays different density distributions and vertical mass profiles to all modes of GIZMO (including the smoothed particle hydrodynamics version). This suggests differences also arise which are not intrinsic to the particular method but rather due to its implementation. The discrepancies between codes (in particular, the densities reached in the spiral arms) could potentially result in differences in the locations and time-scales for gravitational collapse, and therefore impact star formation activity in more complex galaxy disc simulations.

  17. A Spatial Domain Quantum Watermarking Scheme

    Science.gov (United States)

    Wei, Zhan-Hong; Chen, Xiu-Bo; Xu, Shu-Jiang; Niu, Xin-Xin; Yang, Yi-Xian

    2016-07-01

    This paper presents a spatial domain quantum watermarking scheme. For a quantum watermarking scheme, a feasible quantum circuit is a key to achieve it. This paper gives a feasible quantum circuit for the presented scheme. In order to give the quantum circuit, a new quantum multi-control rotation gate, which can be achieved with quantum basic gates, is designed. With this quantum circuit, our scheme can arbitrarily control the embedding position of watermark images on carrier images with the aid of auxiliary qubits. Besides reversely acting the given quantum circuit, the paper gives another watermark extracting algorithm based on quantum measurements. Moreover, this paper also gives a new quantum image scrambling method and its quantum circuit. Differ from other quantum watermarking schemes, all given quantum circuits can be implemented with basic quantum gates. Moreover, the scheme is a spatial domain watermarking scheme, and is not based on any transform algorithm on quantum images. Meanwhile, it can make sure the watermark be secure even though the watermark has been found. With the given quantum circuit, this paper implements simulation experiments for the presented scheme. The experimental result shows that the scheme does well in the visual quality and the embedding capacity. Supported by the National Natural Science Foundation of China under Grant Nos. 61272514, 61170272, 61373131, 61121061, 61411146001, the program for New Century Excellent Talents under Grant No. NCET-13-0681, the National Development Foundation for Cryptological Research (Grant No. MMJJ201401012) and the Fok Ying Tung Education Foundation under Grant No. 131067, and the Shandong Provincial Natural Science Foundation of China under Grant No. ZR2013FM025

  18. Improved Quantum Signature Scheme with Weak Arbitrator

    Science.gov (United States)

    Su, Qi; Li, Wen-Min

    2013-09-01

    In this paper, we find a man-in-the-middle attack on the quantum signature scheme with a weak arbitrator (Luo et al., Int. J. Theor. Phys., 51:2135, 2012). In that scheme, the authors proposed a quantum signature based on quantum one way function which contains both verifying the signer phase and verifying the signed message phase. However, after our analysis we will show that Eve can adopt different strategies in respective phases to forge the signature without being detected. Then we present an improved scheme to increase the security.

  19. EFFICIENT IMAGE TRANSMISSION SCHEME IN FMT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Qi Zhongrui; Gao Zhenming

    2005-01-01

    An efficient image transmission scheme is proposed based on byte partition and adaptive sub-channel distribution technique in Filtered MultiTone (FMT) system over frequency selective slow fading channel. According to the simulation results and analysis of a typical image with matlab, improvement in Peak Signal to Noise Ratio (PSNR) of the received image and low complexity for equalization is demonstrated remarkably. Comparing with no adaptive and no actual channel equalization scheme, the proposed scheme saves over 6 dB when PSNR=40 dB.

  20. A SUBDIVISION SCHEME FOR VOLUMETRIC MODELS

    Institute of Scientific and Technical Information of China (English)

    GhulamMustafa; LiuXuefeng

    2005-01-01

    In this paper, a subdivision scheme which generalizes a surface scheme in previous papers to volume meshes is designed. The scheme exhibits significant control over shrink-age/size of volumetric models. It also has the ability to conveniently incorporate boundaries and creases into a smooth limit shape of models. The method presented here is much simpler and easier as compared to MacCracken and Joy's. This method makes no restrictions on the local topology of meshes. Particularly, it can be applied without any change to meshes of nonmanifold topology.

  1. A classification scheme for chimera states

    Science.gov (United States)

    Kemeth, Felix P.; Haugland, Sindre W.; Schmidt, Lennart; Kevrekidis, Ioannis G.; Krischer, Katharina

    2016-09-01

    We present a universal characterization scheme for chimera states applicable to both numerical and experimental data sets. The scheme is based on two correlation measures that enable a meaningful definition of chimera states as well as their classification into three categories: stationary, turbulent, and breathing. In addition, these categories can be further subdivided according to the time-stationarity of these two measures. We demonstrate that this approach is both consistent with previously recognized chimera states and enables us to classify states as chimeras which have not been categorized as such before. Furthermore, the scheme allows for a qualitative and quantitative comparison of experimental chimeras with chimeras obtained through numerical simulations.

  2. Consistency of non-minimal renormalisation schemes

    CERN Document Server

    Jack, I

    2016-01-01

    Non-minimal renormalisation schemes such as the momentum subtraction scheme (MOM) have frequently been used for physical computations. The consistency of such a scheme relies on the existence of a coupling redefinition linking it to MSbar. We discuss the implementation of this procedure in detail for a general theory and show how to construct the relevant redefinition up to three-loop order, for the case of a general theory of fermions and scalars in four dimensions and a general scalar theory in six dimensions.

  3. Chaotic cryptographic scheme and its randomness evaluation

    Science.gov (United States)

    Stoyanov, B. P.

    2012-10-01

    We propose a new cryptographic scheme based on the Lorenz chaos attractor and 32 bit bent Boolean function. We evaluated the keystream generated by the scheme with batteries of the NIST statistical tests. We also applied a number of statistical analysis techniques, such as calculating histograms, correlations between two adjacent pixels, information entropy, and differential resistance, all refer to images encrypted by the proposed system. The results of the analysis show that the new cryptographic scheme ensures a secure way for sending digital data with potential applications in real-time image encryption.

  4. An Optimal Labeling Scheme for Ancestry Queries

    OpenAIRE

    2009-01-01

    An ancestry labeling scheme assigns labels (bit strings) to the nodes of rooted trees such that ancestry queries between any two nodes in a tree can be answered merely by looking at their corresponding labels. The quality of an ancestry labeling scheme is measured by its label size, that is the maximal number of bits in a label of a tree node. In addition to its theoretical appeal, the design of efficient ancestry labeling schemes is motivated by applications in web search engines. For this p...

  5. Finite-volume scheme for anisotropic diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Es, Bram van, E-mail: bramiozo@gmail.com [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands)

    2016-02-01

    In this paper, we apply a special finite-volume scheme, limited to smooth temperature distributions and Cartesian grids, to test the importance of connectivity of the finite volumes. The area of application is nuclear fusion plasma with field line aligned temperature gradients and extreme anisotropy. We apply the scheme to the anisotropic heat-conduction equation, and compare its results with those of existing finite-volume schemes for anisotropic diffusion. Also, we introduce a general model adaptation of the steady diffusion equation for extremely anisotropic diffusion problems with closed field lines.

  6. Practical Coding Schemes for Cognitive Overlay Radios

    CERN Document Server

    Kurniawan, Ernest; Rini, Stefano

    2012-01-01

    We develop practical coding schemes for the cognitive overlay radios as modeled by the cognitive interference channel, a variation of the classical two user interference channel where one of the transmitters has knowledge of both messages. Inspired by information theoretical results, we develop a coding strategy for each of the three parameter regimes where capacity is known. A key feature of the capacity achieving schemes in these regimes is the joint decoding of both users' codewords, which we accomplish by performing a posteriori probability calculation over a combined trellis. The schemes are shown to perform close to the capacity limit with low error rate.

  7. Exploiting Same Scale Similarity in Fisher's Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yao

    2001-01-01

    The method proposed by Y. Fisher is the most popular fractal image coding scheme. In his scheme, domain blocks are constrained to be twice as large as range blocks in order to ensure the convergence of the iterative decoding stage. However,this constraint has limited the fractal encoder to exploit the self-similarity of the original image. In order to overcome the shortcoming, a novel scheme using same-sized range and domain blocks is proposed in the paper. Experimental results show the improvements in compression performance.

  8. Mission Mangalam scheme: Ex ploring the opportunities.

    Directory of Open Access Journals (Sweden)

    Dr. Pallavi A. Upadhyay*,

    2015-01-01

    Full Text Available Background Mission Mangalam has been launched by the Gujarat Government in 2010.It is an integrated poverty alleviation approach and an initiative to empower women. Mission Mangalam is helping women to earn their livelihood and to become independent. These Sakhimandals are linked to banks to fulfill the requirement of fund. Sakhimandals get financial assistance from banks. Some of the core benefits of the scheme can be linked with the health sector as well; Objectives (1 To review the scheme of Mission Mangalam (2 To explore the possibility of health linkage with the scheme (3 To study the perception of beneficiaries and their socio- demographic profile; Methodology: A cross sectional study. Samplesize-152 women members of Sakhimandals in Saraspur ward. Health of all the members of Mandals of Saraspur was checked by the Ahmedabad Municipal Corporation. Women of Sakhimandals were interviewed to understand their perception about the scheme as well as about any other health benefit they have experienced for themselves or their family members. 3 Additionally, Community based survey of 50 BPL families was carried out to assess the proportion of families covered under the scheme of Mission Mangalam. Results: Mean age of these women (n=152 was 31.81 years with SD=6.74. Education of maximum number 71(47% of women was up to secondary. Mean income was 5460 Rs/month with SD=1840 .Mean of number of family members is 5.4. 109 (72% women are residing in chali area. 98(64% women were told about this scheme by social worker, others were told about the scheme by her friend or UCD official. Paired t test was carried out to find increase in Hb levels of the beneficiary women. It was found to be significant (p=0.007, t=15.64. Age of women is associated with habit to save money. (p=0.003. There are only 22 (44% out of 50 families visited, who have at least one member enrolled under the scheme. More stringent efforts for universal coverage have to be made by

  9. Cognitive radio networks dynamic resource allocation schemes

    CERN Document Server

    Wang, Shaowei

    2014-01-01

    This SpringerBrief presents a survey of dynamic resource allocation schemes in Cognitive Radio (CR) Systems, focusing on the spectral-efficiency and energy-efficiency in wireless networks. It also introduces a variety of dynamic resource allocation schemes for CR networks and provides a concise introduction of the landscape of CR technology. The author covers in detail the dynamic resource allocation problem for the motivations and challenges in CR systems. The Spectral- and Energy-Efficient resource allocation schemes are comprehensively investigated, including new insights into the trade-off

  10. SUPPLEMENT AND IMPROVEMENT OF HOLLY-PREISSMANN SCHEME

    Institute of Scientific and Technical Information of China (English)

    XIE Zuo-tao; ZHANG Xiao-feng; TAN Guang-ming

    2004-01-01

    Using the undetermined coefficient method, Holly-Preissmann scheme is improved effectively. The scheme with the minus velocity is added, and a new conservative scheme is also presented on the basis of original scheme. The simulations of the new scheme accord with the exact result, which enhances its applicability in the engineering.

  11. DEVELOPMENT AND APPLICATIONS OF WENO SCHEMES IN CONTINUUM PHYSICS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper briefly presents the general ideas of high order accurate weighted essentially non-oscillatory (WENO) schemes, and describes the similarities and differences of the two classes of WENO schemes: finite volume schemes and finite difference schemes. We also briefly mention a recent development of WENO schemes,namely an adaptive approach within the finite difference framework using smooth time dependent curvilinear coordinates.``

  12. Twin-Schnorr: A Security Upgrade for the Schnorr Identity-Based Identification Scheme

    Directory of Open Access Journals (Sweden)

    Ji-Jian Chin

    2015-01-01

    Full Text Available Most identity-based identification (IBI schemes proposed in recent literature are built using pairing operations. This decreases efficiency due to the high operation costs of pairings. Furthermore, most of these IBI schemes are proven to be secure against impersonation under active and concurrent attacks using interactive assumptions such as the one-more RSA inversion assumption or the one-more discrete logarithm assumption, translating to weaker security guarantees due to the interactive nature of these assumptions. The Schnorr-IBI scheme was first proposed through the Kurosawa-Heng transformation from the Schnorr signature. It remains one of the fastest yet most secure IBI schemes under impersonation against passive attacks due to its pairing-free design. However, when required to be secure against impersonators under active and concurrent attacks, it deteriorates greatly in terms of efficiency due to the protocol having to be repeated multiple times. In this paper, we upgrade the Schnorr-IBI scheme to be secure against impersonation under active and concurrent attacks using only the classical discrete logarithm assumption. This translates to a higher degree of security guarantee with only some minor increments in operational costs. Furthermore, because the scheme operates without pairings, it still retains its efficiency and superiority when compared to other pairing-based IBI schemes.

  13. A lightweight authentication scheme with user untraceability

    Institute of Scientific and Technical Information of China (English)

    Kuo-Hui YEH

    2015-01-01

    With the rapid growth of electronic commerce and associated demands on variants of Internet based applications, application systems providing network resources and business services are in high demand around the world. To guarantee ro-bust security and computational efficiency for service retrieval, a variety of authentication schemes have been proposed. How-ever, most of these schemes have been found to be lacking when subject to a formal security analysis. Recently, Changet al. (2014) introduced a formally provable secure authentication protocol with the property of user-untraceability. Unfortunately, based on our analysis, the proposed scheme fails to provide the property of user-untraceability as claimed, and is insecure against user impersonation attack, server counterfeit attack, and man-in-the-middle attack. In this paper, we demonstrate the details of these malicious attacks. A security enhanced authentication scheme is proposed to eliminate all identified weaknesses.

  14. An efficient medical image compression scheme.

    Science.gov (United States)

    Li, Xiaofeng; Shen, Yi; Ma, Jiachen

    2005-01-01

    In this paper, a fast lossless compression scheme is presented for the medical image. This scheme consists of two stages. In the first stage, a Differential Pulse Code Modulation (DPCM) is used to decorrelate the raw image data, therefore increasing the compressibility of the medical image. In the second stage, an effective scheme based on the Huffman coding method is developed to encode the residual image. This newly proposed scheme could reduce the cost for the Huffman coding table while achieving high compression ratio. With this algorithm, a compression ratio higher than that of the lossless JPEG method for image can be obtained. At the same time, this method is quicker than the lossless JPEG2000. In other words, the newly proposed algorithm provides a good means for lossless medical image compression.

  15. The Effective Key Length of Watermarking Schemes

    CERN Document Server

    Bas, Patrick

    2012-01-01

    Whereas the embedding distortion, the payload and the robustness of digital watermarking schemes are well understood, the notion of security is still not completely well defined. The approach proposed in the last five years is too theoretical and solely considers the embedding process, which is half of the watermarking scheme. This paper proposes a new measurement of watermarking security, called the effective key length, which captures the difficulty for the adversary to get access to the watermarking channel. This new methodology is applied to additive spread spectrum schemes where theoretical and practical computations of the effective key length are proposed. It shows that these schemes are not secure as soon as the adversary gets observations in the Known Message Attack context.

  16. Lifting scheme of symmetric tight wavelets frames

    Institute of Scientific and Technical Information of China (English)

    ZHUANG BoJin; YUAN WeiTao; PENG LiZhong

    2008-01-01

    This paper proposes a method to realize the lifting scheme of tight frame wavelet filters. As for 4-channel tight frame wavelet filter, the tight frame transforms' ma-trix is 2×4, but the lifting scheme transforms' matrix must be 4×4. And in the case of 3-channel tight frame wavelet filter, the transforms' matrix is 2×3, but the lifting scheme transforms' matrix must be 3×3. In order to solve this problem, we intro-duce two concepts: transferred polyphase matrix for 4-channel filters and trans-ferred unitary matrix for 3-channel filters. The transferred polyphase matrix is sym-metric/antisymmetric. Thus, we use this advantage to realize the lifting scheme.

  17. Efficient Identity Based Public Verifiable Signcryption Scheme

    CERN Document Server

    Kushwah, Prashant

    2011-01-01

    Signcryption is a cryptographic primitive which performs encryption and signature in a single logical step. In conventional signcryption only receiver of the signcrypted text can verify the authenticity of the origin i.e. signature of the sender on the message after decrypting the cipher text. In public verifiable signcryption scheme anyone can verify the authenticity of the origin who can access the signcrypted text i.e. signature of the sender on the cipher text. Public verifiable signcryption scheme in which the receiver can convince a third party, by providing additional information other than his private key along with the signcryption is called third party verifiable signcryption schemes. In this paper we proposed an efficient identity based public verifiable signcryption scheme with third party verification and proved its security in the random oracle model.

  18. Torsion-free Sheaves and ACM Schemes

    CERN Document Server

    Greco, S; Spreafico, M L

    2012-01-01

    In this paper we study short exact sequences $ 0 \\to \\mathcal P \\to \\mathcal N \\to \\ii_D(k) \\to 0 $ with $ \\mathcal P, \\mathcal N $ torsion--free sheaves and $ D $ closed projective scheme. This is a classical way to construct and study projective schemes (e.g. see \\cite{hart-1974}, \\cite{hart-2}, \\cite{mdp}, \\cite{serre-1960}). In particular, we give homological conditions on $ \\mathcal P $ and $ \\mathcal N $ that force $ D $ to be ACM, without constrains on its codimension. As last result, we prove that if $ \\mathcal N $ is a higher syzygy sheaf of an ACM scheme $ X,$ the scheme $ D $ we get contains $ X.$

  19. High order compact schemes for gradient approximation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we propose three gradient recovery schemes of higher order for the linear interpolation. The first one is a weighted averaging method based on the gradients of the linear interpolation on the uniform mesh, the second is a geometric averaging method constructed from the gradients of two cubic interpolation on macro element, and the last one is a local least square method on the nodal patch with cubic polynomials. We prove that these schemes can approximate the gradient of the exact solution on the symmetry points with fourth order. In particular, for the uniform mesh, we show that these three schemes are the same on the considered points. The last scheme is more robust in general meshes. Consequently, we obtain the superconvergence results of the recovered gradient by using the aforementioned results and the supercloseness between the finite element solution and the linear interpolation of the exact solution. Finally, we provide several numerical experiments to illustrate the theoretical results.

  20. Certificateless universal designated verifier signature schemes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Universal designated verifier signature schemes allows a signature holder to designate the signature to a desire designated verifier, in such a way that only designated verifier can verify this signature, but is unable to convince anyone else of this fact.The previous constructions of universal designated verifier signature rely on the underlying public key infrastructure, that needs both signers and verifiers to verify the authenticity of the public keys, and hence, the certificates are required.This article presents the first model and construction of the certificateless universal designated verifier signature scheme, in which the certificates are not needed.The proposed scheme satisfies all the requirements of the universal designated verifier signature in the certificateless system.Security proofs are provided for the scheme based on the random oracle model, assuming that the Bilinear diffie-hellman (BDH) problem is hard to solve.

  1. ONU Power Saving Scheme for EPON System

    Science.gov (United States)

    Mukai, Hiroaki; Tano, Fumihiko; Tanaka, Masaki; Kozaki, Seiji; Yamanaka, Hideaki

    PON (Passive Optical Network) achieves FTTH (Fiber To The Home) economically, by sharing an optical fiber among plural subscribers. Recently, global climate change has been recognized as a serious near term problem. Power saving techniques for electronic devices are important. In PON system, the ONU (Optical Network Unit) power saving scheme has been studied and defined in XG-PON. In this paper, we propose an ONU power saving scheme for EPON. Then, we present an analysis of the power reduction effect and the data transmission delay caused by the ONU power saving scheme. According to the analysis, we propose an efficient provisioning method for the ONU power saving scheme which is applicable to both of XG-PON and EPON.

  2. A New Efficient Mobile Micropayment Scheme

    Institute of Scientific and Technical Information of China (English)

    FU Xiong; YANG Zong-kai; LANG Wei-min; TAN Yun-meng

    2004-01-01

    This paper proposes a micropayment scheme designed for GSM mobile scenario, where the overload of computation, storage and communication for mobile phone is reduced by directing operations normally performed by the mobile user to the static portion of the network in view of its limited capability. Messages which received and sent during the payment are very simple and public key infrastructure is not needed, which reduces delay and removes the possibility of incomplete payment due to communications failures. Furthermore, all the information related to payment is encrypted by a shared symmetric key in our scheme, so the privacy of the mobile user is protected and the security of information is guaranteed. Compared with other mobile micropayment schemes in existence, no public-key operation is required, which minimizes the computation and storage overhead dramatically. In addition, restricted anonymous is also provided in our scheme.

  3. Broadcast encryption schemes based on RSA

    Institute of Scientific and Technical Information of China (English)

    MU Ning-bo; HU Yu-pu; OU Hai-wen

    2009-01-01

    Three broadcast schemes for small receiver set using the property of RSA modulus are presented. They can solve the problem of data redundancy when the size of receiver set is small. In the proposed schemes, the center uses one key to encrypt the message and can revoke authorization conveniently. Every authorized user only needs to store one decryption key of a constant size. Among these three schemes, the first one has indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) secure, and any collusion of authorized users cannot produce a new decryption key but the sizes of encryption modulus and ciphertext are linear in the number of receivers. In the second scheme, the size of ciphertext is half of the first one and any two authorized users can produce a new decryption key, but the center can identify them using the traitor tracing algorithm. The third one is the most efficient but the center cannot identify the traitors exactly.

  4. Renormalization Scheme Dependence and Renormalization Group Summation

    CERN Document Server

    McKeon, D G C

    2016-01-01

    We consider logarithmic contributions to the free energy, instanton effective action and Laplace sum rules in QCD that are a consequence of radiative corrections. Upon summing these contributions by using the renormalization group, all dependence on the renormalization scale parameter mu cancels. The renormalization scheme dependence in these processes is examined, and a renormalization scheme is found in which the effect of higher order radiative corrections is absorbed by the behaviour of the running coupling.

  5. Composite centered schemes for multidimensional conservation laws

    Energy Technology Data Exchange (ETDEWEB)

    Liska, R. [Czech Technical Univ., Prague (Czech Republic). Faculty of Nuclear Sciences and Physical Engineering; Wendroff, B. [Los Alamos National Lab., NM (United States)

    1998-05-08

    The oscillations of a centered second order finite difference scheme and the excessive diffusion of a first order centered scheme can be overcome by global composition of the two, that is by performing cycles consisting of several time steps of the second order method followed by one step of the diffusive method. The authors show the effectiveness of this approach on some test problems in two and three dimensions.

  6. GROUP VELOCITY CONTROL SCHEME WITH LOW DISSIPATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to prevent smearing the discontinuity, a modified term is added to the third order Upwind Compact Difference scheme to lower the dissipation error. Moreover, the dispersion error is controled to hold back the non-physical oscillation by means of the group velocity control. The scheme is used to simulate the interactions of shock-density stratified interface and the disturbed interface developing to vortex rollers. Numerical results are satisfactory.

  7. Toric varieties, monoid schemes and $cdh$ descent

    CERN Document Server

    Cortiñas, Guillermo; Walker, Mark E; Weibel, Charles A

    2011-01-01

    We give conditions for the Mayer-Vietoris property to hold for the algebraic K-theory of blow-up squares of toric varieties in any characteristic, using the theory of monoid schemes. These conditions are used to relate algebraic K-theory to topological cyclic homology in characteristic p. To achieve our goals, we develop for monoid schemes many notions from classical algebraic geometry, such as separated and proper maps.

  8. A modified scheme for biotyping Gardnerella vaginalis.

    Science.gov (United States)

    Benito, R; Vazquez, J A; Berron, S; Fenoll, A; Saez-Neito, J A

    1986-06-01

    A scheme is proposed for biotyping Gardnerella vaginalis, based on detection of hippurate hydrolysis, beta-galactosidase (ONPG) and lipase, and fermentation of arabinose, galactose and xylose. Seventeen biotypes were found among 197 strains from asymptomatic women and patients with bacterial vaginosis (non-specific vaginitis). The distribution of biotypes was similar in both populations but some biotypes were found more frequently in patients. The proposed scheme is compared with those previously described.

  9. Advanced switching schemes in a Stark decelerator

    CERN Document Server

    Zhang, Dongdong; Meijer, Gerard

    2015-01-01

    We revisit the operation of the Stark decelerator and present a new, optimized operation scheme, which substantially improves the efficiency of the decelerator at both low and high final velocities, relevant for trapping experiments and collision experiments, respectively. Both experimental and simulation results show that this new mode of operation outperforms the schemes which have hitherto been in use. This new mode of operation could potentially be extended to other deceleration techniques.

  10. Readout scheme of the upgraded ALICE TPC

    CERN Document Server

    Appelshaeuser, Harald; Ivanov, Marian; Lippmann, Christian; Wiechula, Jens

    2016-01-01

    In this document, we present the updated readout scheme for the ALICE TPC Upgrade. Two major design changes are implemented with respect to the concept that was presented in the TPC Upgrade Technical Design Report: – The SAMPA front-end ASIC will be used in direct readout mode. – The ADC sampling frequency will be reduced from 10 to 5 MHz. The main results from simulations and a description of the new readout scheme is outlined.

  11. Binary Schemes of Vapor Bubble Growth

    Science.gov (United States)

    Zudin, Yu. B.

    2015-05-01

    A problem on spherically symmetric growth of a vapor bubble in an infi nite volume of a uniformly superheated liquid is considered. A description of the limiting schemes of bubble growth is presented. A binary inertial-thermal bubble growth scheme characterized by such specifi c features as the "three quarters" growth law and the effect of "pressure blocking" in a vapor phase is considered.

  12. Problems of robustness for universal coding schemes

    OpenAIRE

    V'yugin, V. V.

    2008-01-01

    The Lempel-Ziv universal coding scheme is asymptotically optimal for the class of all stationary ergodic sources. A problem of robustness of this property under small violations of ergodicity is studied. A notion of deficiency of algorithmic randomness is used as a measure of disagreement between data sequence and probability measure. We prove that universal compressing schemes from a large class are non-robust in the following sense: if the randomness deficiency grows arbitrarily slowly on i...

  13. Electronic Payment Scheme to Prevent the Treachery

    Institute of Scientific and Technical Information of China (English)

    FAN Kai; ZHANG Jun; KOU Weidong; XIAO Guozhen

    2006-01-01

    Treachery is one of the restrictions to the development of electronic commerce. To prevent the treachery from the participants in electronic commerce, in this paper a secure electronic payment scheme is proposed and its security is analyzed. This scheme can prevent the treachery only with the aid of an un-trusted third party. It is very simple and it also improves the security and provides the non-repudiation, accountability, fairness and privacy.

  14. Simplification of the unified gas kinetic scheme

    Science.gov (United States)

    Chen, Songze; Guo, Zhaoli; Xu, Kun

    2016-08-01

    The unified gas kinetic scheme (UGKS) is an asymptotic preserving (AP) scheme for kinetic equations. It is superior for transition flow simulation and has been validated in the past years. However, compared to the well-known discrete ordinate method (DOM), which is a classical numerical method solving the kinetic equations, the UGKS needs more computational resources. In this study, we propose a simplification of the unified gas kinetic scheme. It allows almost identical numerical cost as the DOM, but predicts numerical results as accurate as the UGKS. In the simplified scheme, the numerical flux for the velocity distribution function and the numerical flux for the macroscopic conservative quantities are evaluated separately. The equilibrium part of the UGKS flux is calculated by analytical solution instead of the numerical quadrature in velocity space. The simplification is equivalent to a flux hybridization of the gas kinetic scheme for the Navier-Stokes (NS) equations and the conventional discrete ordinate method. Several simplification strategies are tested, through which we can identify the key ingredient of the Navier-Stokes asymptotic preserving property. Numerical tests show that, as long as the collision effect is built into the macroscopic numerical flux, the numerical scheme is Navier-Stokes asymptotic preserving, regardless the accuracy of the microscopic numerical flux for the velocity distribution function.

  15. A NEW SCHEME BASED ON THE MI SCHEME AND ITS ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    Jiao Luyao; Li Yifa; Qiao Shuaiting

    2013-01-01

    This article aims at designing a new Multivariate Quadratic (MQ) public-key scheme to avoid the linearization attack and differential attack against the Matsumoto-Imai (MI) scheme.Based on the original scheme,our new scheme,named the Multi-layer MI (MMI) scheme,has a structure of multi-layer central map.Firstly,this article introduces the MI scheme and describes linearization attack and differential attack; then prescribes the designation of MMI in detail,and proves that MMI can resist both linearization attack and differential attack.Besides,this article also proves that MMI can resist recent eXtended Linearization (XL)-like methods.In the end,this article concludes that MMI also maintains the efficiency of MI.

  16. A universal encoding scheme for MIMO transmission using a single active element for PSK modulation schemes

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Papadias, C.B.; Kalis, A.

    2009-01-01

    system by expanding the far-field of a compact parasitic array into an orthogonal set of angular functions (basis). Independent information streams are encoded by means of angular variations of the far-field in the wavevector domain, rather than spatial variations as usually happens in conventional MIMO...

  17. Analysis and Improvement of Authenticatable Ring Signcryption Scheme

    Institute of Scientific and Technical Information of China (English)

    LI Fa-gen; Shirase Masaaki; Takagi Tsuyoshi

    2008-01-01

    We show that the Zhang-Yang-Zhu-Zhang identity-based authenticatable ring signcryption scheme is not secure against chosen plaintext attacks.Furthermore,we propose an improved scheme that remedies the weakness of the Zhang-Yang-Zhu-Zhang scheme.The improved scheme has shorter ciphertext size than the Zhang-Yang-Zhu-Zhang scheme.We then prove that the improved scheme satisfies confidentiality,unforgeability,anonymity and authenticatability.

  18. Cryptanalysis and Improvement of Piveteau Signature Scheme with Message Recovery

    Institute of Scientific and Technical Information of China (English)

    李子臣; 成军祥; 戴一奇

    2003-01-01

    Piveteau signature scheme allows message recovery but the methodology differs from that of the Nyberg-Rueppel schemes. This paper analyzes the security of the Piveteau scheme by designing some attacks. Two improved methods to Piveteau signature scheme and Nyberg-Rueppel schemes were developed to avoid these weaknesses. Analyses of the security of the improved schemes prove that the improved methods can effectively handle the attacks proposed in this paper.

  19. Combining image-processing and image compression schemes

    Science.gov (United States)

    Greenspan, H.; Lee, M.-C.

    1995-01-01

    An investigation into the combining of image-processing schemes, specifically an image enhancement scheme, with existing compression schemes is discussed. Results are presented on the pyramid coding scheme, the subband coding scheme, and progressive transmission. Encouraging results are demonstrated for the combination of image enhancement and pyramid image coding schemes, especially at low bit rates. Adding the enhancement scheme to progressive image transmission allows enhanced visual perception at low resolutions. In addition, further progressing of the transmitted images, such as edge detection schemes, can gain from the added image resolution via the enhancement.

  20. Feasibility analysis of two identity- based proxy ring signature schemes

    Institute of Scientific and Technical Information of China (English)

    Wang Huaqun; Zhang Lijun; Zhao Junxi

    2007-01-01

    Recently , proxy ring signature schemes have been shown to be useful in various applications , such as electronic polling, electronic payment, etc. Although many proxy ring signature schemes have been proposed, there are only two identity- based proxy ring signature schemes have been proposed until now, I.e., Cheng's scheme and Lang's scheme. It's unlucky that the two identity- based proxy ring signature schemes are unfeasible . This paper points out the reasons why the two identity- based proxy ring signature schemes are unfeasible. In order to design feasible and efficient identity-based proxy ring signature schemes from bilinear pairings , we have to search for other methods .

  1. Development of trigger scheme for the ICAL detector of India-based Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, S., E-mail: sudeshnadasgupta@tifr.res.in [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Mondal, N.K.; Samuel, D.; Saraf, M.N.; Satyanarayana, B.; Upadhya, S.S. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2012-06-21

    The India-based Neutrino Observatory (INO) collaboration has proposed to build a 50 kton magnetized Iron Calorimeter (ICAL) detector with the primary goal to study neutrino oscillations, employing Resistive Plate Chambers (RPCs) as active detector elements. Various aspects of a proposed trigger scheme for the ICAL detector are discussed. The associated chance trigger rates are calculated and the trigger efficiency of the scheme for the events of interest for the ICAL detector is determined. An approach toward the implementation of the scheme is also presented.

  2. Seasonal activity and morphological changes in martian gullies

    Science.gov (United States)

    Dundas, Colin M.; Diniega, Serina; Hansen, Candice J.; Byrne, Shane; McEwen, Alfred S.

    2012-01-01

    Recent studies of martian dune and non-dune gullies have suggested a seasonal control on present-day gully activity. The timing of current gully activity, especially activity involving the formation or modification of channels (which commonly have been taken as evidence of fluvial processes), has important implications regarding likely gully formation processes and necessary environmental conditions. In this study, we describe the results of frequent meter-scale monitoring of several active gully sites by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO). The aim is to better assess the scope and nature of current morphological changes and to provide improved constraints on timing of gully activity on both dune and non-dune slopes. Our observations indicate that (1) gully formation on Mars is ongoing today and (2) the most significant morphological changes are strongly associated with seasonal frost and defrosting activity. Observed changes include formation of all major components of typical gully landforms, although we have not observed alcove formation in coherent bedrock. These results reduce the need to invoke recent climate change or present-day groundwater seepage to explain the many martian gullies with pristine appearance.

  3. Short-Term Saved Leave Scheme

    CERN Multimedia

    HR Department

    2007-01-01

    As announced at the meeting of the Standing Concertation Committee (SCC) on 26 June 2007 and in http://Bulletin No. 28/2007, the existing Saved Leave Scheme will be discontinued as of 31 December 2007. Staff participating in the Scheme will shortly receive a contract amendment stipulating the end of financial contributions compensated by save leave. Leave already accumulated on saved leave accounts can continue to be taken in accordance with the rules applicable to the current scheme. A new system of saved leave will enter into force on 1 January 2008 and will be the subject of a new im-plementation procedure entitled "Short-term saved leave scheme" dated 1 January 2008. At its meeting on 4 December 2007, the SCC agreed to recommend the Director-General to approve this procedure, which can be consulted on the HR Department’s website at the following address: https://cern.ch/hr-services/services-Ben/sls_shortterm.asp All staff wishing to participate in the new scheme ...

  4. Short-Term Saved Leave Scheme

    CERN Multimedia

    2007-01-01

    As announced at the meeting of the Standing Concertation Committee (SCC) on 26 June 2007 and in http://Bulletin No. 28/2007, the existing Saved Leave Scheme will be discontinued as of 31 December 2007. Staff participating in the Scheme will shortly receive a contract amendment stipulating the end of financial contributions compensated by save leave. Leave already accumulated on saved leave accounts can continue to be taken in accordance with the rules applicable to the current scheme. A new system of saved leave will enter into force on 1 January 2008 and will be the subject of a new implementation procedure entitled "Short-term saved leave scheme" dated 1 January 2008. At its meeting on 4 December 2007, the SCC agreed to recommend the Director-General to approve this procedure, which can be consulted on the HR Department’s website at the following address: https://cern.ch/hr-services/services-Ben/sls_shortterm.asp All staff wishing to participate in the new scheme a...

  5. Dynamic Localization Schemes in Malicious Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kaiqi Xiong

    2009-10-01

    Full Text Available Wireless sensor networks (WSN have recently shown many potential military and civilian applications, especially those used in hostile environments where malicious adversaries can be present. The accuracy of location information is critical for such applications. It is impractical to have a GPS device on each sensor in WSN due to costs. Most of the existing location discovery schemes can only be used in the trusted environment. Recent research has addressed security issues in sensor network localization, but to the best of our knowledge, none have completely solved the secure localization problem. In this paper, we propose novel schemes for secure dynamic localization in sensor networks. These proposed schemes can tolerate up to 50% of beacon nodes being malicious, and they have linear computation time with respect to the number of reference nodes. Our security analysis has showed that our schemes are applicable and resilient to attacks from adversaries. We have further conducted simulations to analyze and compare the performance of these schemes, and to indicate when each should be used. The efficiencies of each method shows why we needed to propose multiple methods.

  6. Application of ADER Scheme in MHD Simulation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanyan; FENG Xueshang; JIANG Chaowei; ZHOU Yufen

    2012-01-01

    The Arbitrary accuracy Derivatives Riemann problem method(ADER) scheme is a new high order numerical scheme based on the concept of finite volume integration,and it is very easy to be extended up to any order of space and time accuracy by using a Taylor time expansion at the cell interface position.So far the approach has been applied successfully to flow mechanics problems.Our objective here is to carry out the extension of multidimensional ADER schemes to multidimensional MHD systems of conservation laws by calculating several MHD problems in one and two dimensions: (ⅰ) Brio-Wu shock tube problem,(ⅱ) Dai-Woodward shock tube problem,(ⅲ) Orszag-Tang MHD vortex problem.The numerical results prove that the ADER scheme possesses the ability to solve MHD problem,remains high order accuracy both in space and time,keeps precise in capturing the shock.Meanwhile,the compared tests show that the ADER scheme can restrain the oscillation and obtain the high order non-oscillatory result.

  7. Financial incentive schemes in primary care

    Directory of Open Access Journals (Sweden)

    Gillam S

    2015-09-01

    Full Text Available Stephen Gillam Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, Cambridge, UK Abstract: Pay-for-performance (P4P schemes have become increasingly common in primary care, and this article reviews their impact. It is based primarily on existing systematic reviews. The evidence suggests that P4P schemes can change health professionals' behavior and improve recorded disease management of those clinical processes that are incentivized. P4P may narrow inequalities in performance comparing deprived with nondeprived areas. However, such schemes have unintended consequences. Whether P4P improves the patient experience, the outcomes of care or population health is less clear. These practical uncertainties mirror the ethical concerns of many clinicians that a reductionist approach to managing markers of chronic disease runs counter to the humanitarian values of family practice. The variation in P4P schemes between countries reflects different historical and organizational contexts. With so much uncertainty regarding the effects of P4P, policy makers are well advised to proceed carefully with the implementation of such schemes until and unless clearer evidence for their cost–benefit emerges. Keywords: financial incentives, pay for performance, quality improvement, primary care

  8. Arbitrated quantum signature schemes without using entangled states

    CERN Document Server

    Zou, Xiangfu

    2010-01-01

    A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or document. For signing quantum messages, some arbitrated quantum signature schemes have being proposed. However, in the existing literature, arbitrated quantum signature schemes depend on entanglement. In this paper, we present two arbitrated quantum signature schemes without utilizing entangled states in the signing phase and the verifying phase. The first proposed scheme can preserve the merits in the existing schemes. Then, we point out, in this scheme and the prior schemes, there exists a problem that Bob can repudiate the integrality of the signatures. To conquer this problem, we construct another arbitrated quantum signature scheme without using quantum entangled states but using a public board. The new scheme has three advantages: it does not utilize entangled states while it can preserve all merits in the existing schemes; the integrality of the signature can avoid being disavowed by the receiver; an...

  9. Convergence of discrete duality finite volume schemes for the cardiac bidomain model

    CERN Document Server

    Andreianov, Boris; Karlsen, Kenneth H; Pierre, Charles

    2010-01-01

    We prove convergence of discrete duality finite volume (DDFV) schemes on distorted meshes for a class of simplified macroscopic bidomain models of the electrical activity in the heart. Both time-implicit and linearised time-implicit schemes are treated. A short description is given of the 3D DDFV meshes and of some of the associated discrete calculus tools. Several numerical tests are presented.

  10. A Traffic Restriction Scheme for Enhancing Carpooling

    Directory of Open Access Journals (Sweden)

    Dong Ding

    2017-01-01

    Full Text Available For the purpose of alleviating traffic congestion, this paper proposes a scheme to encourage travelers to carpool by traffic restriction. By a variational inequity we describe travelers’ mode (solo driving and carpooling and route choice under user equilibrium principle in the context of fixed demand and detect the performance of a simple network with various restriction links, restriction proportions, and carpooling costs. Then the optimal traffic restriction scheme aiming at minimal total travel cost is designed through a bilevel program and applied to a Sioux Fall network example with genetic algorithm. According to various requirements, optimal restriction regions and proportions for restricted automobiles are captured. From the results it is found that traffic restriction scheme is possible to enhance carpooling and alleviate congestion. However, higher carpooling demand is not always helpful to the whole network. The topology of network, OD demand, and carpooling cost are included in the factors influencing the performance of the traffic system.

  11. Ciphertext verification security of symmetric encryption schemes

    Institute of Scientific and Technical Information of China (English)

    HU ZhenYu; SUN FuChun; JIANG JianChun

    2009-01-01

    This paper formally discusses the security problem caused by the ciphertext verification,presenting a new security notion named IND-CVA (indistinguishability under ciphertext verification attacks) to chap acterize the privacy of encryption schemes in this situation.Allowing the adversary to access to both encryption oracle and ciphertext verification oracle,the new notion IND-CVA is slightly stronger than IND-CPA (indistinguishability under chosen-plaintext attacks) but much weaker than IND-CCA (indistinguishability under chosen-ciphertext attacks),and can be satisfied by most of the popular symmetric encryption schemes such as OTP (one-time-pad),CBC (cipher block chaining) and CTR (counter).An MAC (message authentication scheme) is usually combined with an encryption to guarantee secure communication (e.g.SSH,SSL and IPSec).However,with the notion of IND-CVA,this paper shows that a secure MAC can spoil the privacy in some cases.

  12. Dropout--Mertonian or reproduction scheme?

    Science.gov (United States)

    Horowitz, T R

    1992-01-01

    This article reports on dropouts in four schools in Israel. Two main research questions were addressed: (1) Is it possible to identify a potential dropout through examination of his/her attitudes and competence before the actual act of leaving school? (2) Is there a difference between dropouts and persistent students in different educational settings (academic, vocational, agricultural, and comprehensive high schools)? Significant differences were found in the attitudes of persistent students and dropouts even before the act of dropping out occurred. In the vocational, comprehensive, and agricultural schools, the dropouts scored more positively on the self-estrangement, meaninglessness, and misfeasance scales. In the academic school, the dropouts scored positively on the anxiety scale. Results were interpreted in light of the Mertonian scheme of ends and means as well as the reproduction scheme. The Mertonian scheme was deemed more applicable.

  13. An ECC-Based Blind Signature Scheme

    Directory of Open Access Journals (Sweden)

    Fuh-Gwo Jeng

    2010-08-01

    Full Text Available Cryptography is increasingly applied to the E-commerce world, especially to the untraceable payment system and the electronic voting system. Protocols for these systems strongly require the anonymous digital signature property, and thus a blind signature strategy is the answer to it. Chaum stated that every blind signature protocol should hold two fundamental properties, blindness and intractableness. All blind signature schemes proposed previously almost are based on the integer factorization problems, discrete logarithm problems, or the quadratic residues, which are shown by Lee et al. that none of the schemes is able to meet the two fundamental properties above. Therefore, an ECC-based blind signature scheme that possesses both the above properties is proposed in this paper.

  14. Integrated Protection Scheme for Power Line

    Institute of Scientific and Technical Information of China (English)

    BO Zhiqian; SHI Shenxing; DONG Xinzhou

    2008-01-01

    This paper presents an integrated relay and its associated protection scheme for power transmission lines. The concept of integrated protection is firstly introduced, in which a centralized protection system or relay provides the protection for multiple power plants or a substation. A novel integrated protection relay based on the combination of a number of protection principles is de- scribed. In the proposed scheme, the specially designed protection relays are installed at each substation of a network and are responsible for the protection of every line section connected to the substation busbar.The combined algorithms with multiple settings are implemented into the relay to cover all the protected line sections.Simulation studies show that the proposed protection scheme is able to produce desirable performance and may offer many advantages over the exist- ing one and great potential for future applications.

  15. Energy-saving PPM schemes for WSNs

    Institute of Scientific and Technical Information of China (English)

    TANG QiuLing; YANG LiuQing; QIN TuanFa; ZHANG ShuYi

    2008-01-01

    Energy conservation is a critical problem in recenlly-emerging wireless sensor networks (WSNs). Pulse position modulation (PPM), as an exploring-worthy modulation format for energy efficiency, is tailored for WSNs into two schemes, mono-mode PPM and multi-mode PPM, in this paper. Resorting to an idealized system model and a practical system model, which combine the power consump-tions in transmission and reception modules of nodes with the idealized and real-istic battery characteristics, the battery energy efficiencies of mono-mode PPM and multi-mode PPM are evaluated and compared. To minimize the battery energy consumption (BEC), these schemes are further optimized in terms of constellation size M for a link in path-loss channels. Our analytical and numerical results show that considerable energy can be saved by multi-mode PPM; and the optimization performances of these schemes are noticeable at various communication dis-tances though their optimization properties are different.

  16. Multi-Seed Key Distribution Scheme Test

    Institute of Scientific and Technical Information of China (English)

    XIE Yumin; SHI Feng; MING Yang; Muhammad Kamran; YANG Xiaoxu

    2006-01-01

    The key problem of securing multicast is to generate, distribute and update Session Encryption Key(SEK). Polynomial expansion with multi-seed(MPE) scheme is an approach which is based on Polynomial expansion(PE) scheme and overcomes PE's shortage. Its operation is demonstrated by using multi-seed, the group member is partitioned to many subgroups. While updating the SEK, computation is needed only in one of subgroups, the other of them will use the computation history to update their SEK. The key problems to design a MPE scheme application includes to find a feasible one way function as well as to generate a Strict Prime Number(SPN). Those technologies with multi-seed and computation history concepts make MPE as a good choice in practical applications. A prototype test system is designed and solutions of all above mentioned problems are included in this proposed paper.

  17. Charge preserving high order PIC schemes

    Energy Technology Data Exchange (ETDEWEB)

    Londrillo, P., E-mail: pasquale.londrillo@oabo.inaf.i [INAF Bologna Osservatorio Astronomico (Italy); INFN Sezione Bologna (Italy); Benedetti, C.; Sgattoni, A.; Turchetti, G. [INFN Sezione Bologna (Italy); Dipartimento di Fisica dell' Universita di Bologna (Italy)

    2010-08-01

    In this paper we present some new results on our investigation aimed at extending to higher order (HOPIC) the classical PIC framework. After reviewing the basic resolution properties of the Runge-Kutta time integrator, coupled to fourth (sixth) order compact schemes for space derivatives in the Maxwell equations, we focus on the problem of extending charge conservation schemes to a general HOPIC framework. This issue represents the main contribution of the present work. We consider then a few numerical examples of 1D laser-plasma interaction in the under-dense and over-dense regimes relevant for ions acceleration, to test grid convergence and to compare HOPIC results with standard PIC schemes (LOPIC).

  18. COPROX fixed bed reactor - temperature control schemes

    Energy Technology Data Exchange (ETDEWEB)

    Giunta, P.; Moreno, M.; Marino, F.; Amadeo, N.; Lobarde, M. [Laboratorio de Procesos Cataliticos, Facultad de Ingenieria, Universidad de Buenos Aires, Buenos Aires (Argentina)

    2012-06-15

    Different temperature control schemes for the COPROX stage of a 5-kW fuel cell system were analyzed. It was found that, among the schemes proposed, i.e., co- and countercurrent heat exchange, single adiabatic reactor and series of adiabatic reactors with interstage heat exchange, the best choice for temperature control was the series of adiabatic reactors with interstage heat exchange. This scheme represented the best way to keep the average temperature around 443 K, which was found to be the most suitable temperature for selectivity towards CO oxidation. If hydrogen is produced from ethanol steam reforming, the heat withdrawal can be carried out by the water/ethanol reformer feed mixture, thus contributing to the energy integration of the overall system. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Vector lifting schemes for stereo image coding.

    Science.gov (United States)

    Kaaniche, Mounir; Benazza-Benyahia, Amel; Pesquet-Popescu, Béatrice; Pesquet, Jean-Christophe

    2009-11-01

    Many research efforts have been devoted to the improvement of stereo image coding techniques for storage or transmission. In this paper, we are mainly interested in lossy-to-lossless coding schemes for stereo images allowing progressive reconstruction. The most commonly used approaches for stereo compression are based on disparity compensation techniques. The basic principle involved in this technique first consists of estimating the disparity map. Then, one image is considered as a reference and the other is predicted in order to generate a residual image. In this paper, we propose a novel approach, based on vector lifting schemes (VLS), which offers the advantage of generating two compact multiresolution representations of the left and the right views. We present two versions of this new scheme. A theoretical analysis of the performance of the considered VLS is also conducted. Experimental results indicate a significant improvement using the proposed structures compared with conventional methods.

  20. IPCT: A scheme for mobile authentication

    Directory of Open Access Journals (Sweden)

    Vishnu Shankar

    2016-09-01

    Full Text Available Mobile is becoming a part of everyone's life and as their power of computation and storage is rising and cost is coming down. Most of mobile phone users have a lot of private data which they want to protect from others (La Polla et al., 2013. It means user must be authenticated properly for accessing the mobile resources. Normally user is authenticated using text passwords, PIN, face recognition or patterns etc. All these methods are used but they have some shortcomings. In this paper we have seen various existing methods of mobile authentications and proposed our improved mobile authentication IPCT scheme. We have compared our Image Pass Code with tapping scheme with existing techniques and shown that our scheme is better than existing techniques.

  1. Loading Schemes for Downlink OFDMA Systems

    Institute of Scientific and Technical Information of China (English)

    KONG Jian; LIU Fang; WANG Wen-bo; LIU Yuan-an

    2004-01-01

    In this paper we study the subcarrier and bit allocation strategies for downlink OFDMA system. Our optimization objective is to find optimum subcarrier and bit assignment minimizing the total transmitted power with the constraints on BER and data rate for all users. We divide this problem into three steps: resource allocation, subcarrier assignment and single-user power and bit allocation. For the first two steps we propose new algorithms. Various loading schemes constitute by combining these algorithms as well as algorithms proposed in Ref . [ 6 ]. Simulation results demonstrate that our proposed suboptimal loading scheme can achieve performance closer to the near optimal algorithm in Ref . [ 8 ] with much lower complexity than schemes in Ref .[6].

  2. Third-order modified coefficient scheme based on essentially non-oscillatory scheme

    Institute of Scientific and Technical Information of China (English)

    LI Ming-jun; YANG Yu-yue; SHU Shi

    2008-01-01

    A third-order numerical scheme is presented to give approximate solutions to multi-dimensional hyperbolic conservation laws only using modified coefficients of an essentially non-oscillatory (MCENO) scheme without increasing the base points during construction of the scheme.The construction process shows that the modified coefficient approach preserves favourable properties inherent in the original essentially non oscillatory (ENO) scheme for its essential non-oscillation,total variation bounded (TVB),etc.The new scheme improves accuracy by one order compared to the original one.The proposed MCENO scheme is applied to simulate two-dimensional Rayleigh-Taylor (RT) instability with densities 1:3 and 1:100,and solve the Lax shock-wave tube numerically.The ratio of CPU time used to implement MCENO,the third-order ENO and fifth-order weighed ENO (WENO) schemes is 0.62:1:2.19.This indicates that MCENO improves accuracy in smooth regions and has higher accuracy and better efficiency compared to the original ENO scheme.

  3. Tradable white certificate schemes : what can we learn from tradable green certificate schemes?

    NARCIS (Netherlands)

    Oikonomou, Vlasis; Mundaca, Luis

    2008-01-01

    In this paper, we analyze the experiences gained from tradable green certificate (TGC) schemes and extract some policy lessons that can lead to a successful design of a market-based approach for energy efficiency improvement, alias tradable white certificate schemes. We use tradable green certificat

  4. A simple angular transmit diversity scheme using a single RF frontend for PSK modulation schemes

    DEFF Research Database (Denmark)

    Alrabadi, Osama Nafeth Saleem; Papadias, Constantinos B.; Kalis, Antonis

    2009-01-01

    array (SPA) with a single transceiver, and an array area of 0.0625 square wavelengths. The scheme which requires no channel state information (CSI) at the transmitter, provides mainly a diversity gain to combat against multipath fading. The performance/capacity of the proposed diversity scheme...

  5. 一种融合用户级和内核级拦截的主动防御方案%Active defense scheme of fusion of user-level and kernel level interception

    Institute of Scientific and Technical Information of China (English)

    许方恒; 陈暄; 唐科萍; 龙丹

    2013-01-01

    Based on the Windows environment procedures mechanism analysis,this paper explored the use of user level intercept,the kernel level intercept which combined with active defense technology of malicious code behavior accurately automatic detection and automatic identification,and proved security system and security of network.The experimental results show that the technology for the unknown malicious code and its variants of the detection ability is better than single method and other traditional methods of detection.%通过对Windows环境下程序机理的分析研究,探索采用用户级别拦截、内核级别拦截相结合的主动防御技术实现对恶意入侵行为自动精确检测和自动识别,保障系统和网络的安全.实验结果表明,该技术对于未知恶意入侵及其变种的检测能力均优于单一方法和其他传统检测方法.

  6. Security problem on arbitrated quantum signature schemes

    Science.gov (United States)

    Choi, Jeong Woon; Chang, Ku-Young; Hong, Dowon

    2011-12-01

    Many arbitrated quantum signature schemes implemented with the help of a trusted third party have been developed up to now. In order to guarantee unconditional security, most of them take advantage of the optimal quantum one-time encryption based on Pauli operators. However, in this paper we point out that the previous schemes provide security only against a total break attack and show in fact that there exists an existential forgery attack that can validly modify the transmitted pair of message and signature. In addition, we also provide a simple method to recover security against the proposed attack.

  7. Security problem on arbitrated quantum signature schemes

    CERN Document Server

    Choi, Jeong Woon; Hong, Dowon

    2011-01-01

    Until now, there have been developed many arbitrated quantum signature schemes implemented with a help of a trusted third party. In order to guarantee the unconditional security, most of them take advantage of the optimal quantum one-time encryption method based on Pauli operators. However, we in this paper point out that the previous schemes only provides a security against total break and actually show that there exists a simple existential forgery attack to validly modify the transmitted pair of message and signature. In addition, we also provide a simple method to recover the security against the proposed attack.

  8. ARQ scheme reinforced with past acknowledgement signals

    Science.gov (United States)

    Nakamura, Makoto; Takada, Yasushi

    An ARQ (automatic-repeat-request) scheme that can reduce the influence of backward channel errors for bidirectional data transmission systems is proposed. The main feature of the scheme is that both present and past acknowledgement signals are utilized to decide whether the data signals should be retransmitted or not. Throughput performance is analyzed in both go-back-N and selective-repeat ARQ. A small number of returned past acknowledgement signals are required to improve the throughput efficiency. For an ideal selective-repeat ARQ with an infinite buffer, increasing the number of returned past acknowledgement signals makes the throughput efficiency asymptotically close to the upper bound.

  9. A Survey of Unix Init Schemes

    CERN Document Server

    Royon, Yvan

    2007-01-01

    In most modern operating systems, init (as in "initialization") is the program launched by the kernel at boot time. It runs as a daemon and typically has PID 1. Init is responsible for spawning all other processes and scavenging zombies. It is also responsible for reboot and shutdown operations. This document describes existing solutions that implement the init process and/or init scripts in Unix-like systems. These solutions range from the legacy and still-in-use BSD and SystemV schemes, to recent and promising schemes from Ubuntu, Apple, Sun and independent developers. Our goal is to highlight their focus and compare their sets of features.

  10. A hierarchical classification scheme of psoriasis images

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær

    2003-01-01

    the normal skin in the second stage. These tools are the Expectation-Maximization Algorithm, the quadratic discrimination function and a classification window of optimal size. Extrapolation of classification parameters of a given image to other images of the set is evaluated by means of Cohen's Kappa......A two-stage hierarchical classification scheme of psoriasis lesion images is proposed. These images are basically composed of three classes: normal skin, lesion and background. The scheme combines conventional tools to separate the skin from the background in the first stage, and the lesion from...

  11. Group Buying Schemes : A Sustainable Business Model?

    OpenAIRE

    Köpp, Sebastian; Mukhachou, Aliaksei; Schwaninger, Markus

    2013-01-01

    Die Autoren gehen der Frage nach, ob "Group Buying Schemes" wie beispielsweise von den Unternehmen Groupon und Dein Deal angeboten, ein nachhaltiges Geschäftsmodell sind. Anhand der Fallstudie Groupon wird mit einem System Dynamics Modell festgestellt, dass das Geschäftsmodell geändert werden muss, wenn die Unternehmung auf Dauer lebensfähig sein soll. The authors examine if group buying schemes are a sustainable business model. By means of the Groupon case study and using a System Dynami...

  12. Fixed Wordsize Implementation of Lifting Schemes

    Science.gov (United States)

    Karp, Tanja

    2006-12-01

    We present a reversible nonlinear discrete wavelet transform with predefined fixed wordsize based on lifting schemes. Restricting the dynamic range of the wavelet domain coefficients due to a fixed wordsize may result in overflow. We show how this overflow has to be handled in order to maintain reversibility of the transform. We also perform an analysis on how large a wordsize of the wavelet coefficients is needed to perform optimal lossless and lossy compressions of images. The scheme is advantageous to well-known integer-to-integer transforms since the wordsize of adders and multipliers can be predefined and does not increase steadily. This also results in significant gains in hardware implementations.

  13. A compression tolerant scheme for image authentication

    Institute of Scientific and Technical Information of China (English)

    刘宝锋; 张文军; 余松煜

    2004-01-01

    Image authentication techniques used to protect the recipients against malicious forgery. In this paper, we propose a new image authentication technique based on digital signature. The authentication is verified by comparing the features of the each block in tested image with the corresponding features of the block recorded in the digital signature. The proposed authentication scheme is capable of distinguishing visible but non-malicious changes due to common processing operations from malicious changes. At last our experimental results show that the proposed scheme is not only efficient to protect integrity of image, but also with low computation,which are feasible for practical applications.

  14. A numerical relativity scheme for cosmological simulations

    CERN Document Server

    Daverio, David; Mitsou, Ermis

    2016-01-01

    Fully non-linear cosmological simulations may prove relevant in understanding relativistic/non-linear features and, therefore, in taking full advantage of the upcoming survey data. We propose a new 3+1 integration scheme which is based on the presence of a perfect fluid (hydro) field, evolves only physical states by construction and passes the robustness test on an FLRW space-time. Although we use General Relativity as an example, the idea behind that scheme is applicable to any generally-covariant modified gravity theory and/or matter content, including a N-body sector.

  15. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  16. A Modified Model Predictive Control Scheme

    Institute of Scientific and Technical Information of China (English)

    Xiao-Bing Hu; Wen-Hua Chen

    2005-01-01

    In implementations of MPC (Model Predictive Control) schemes, two issues need to be addressed. One is how to enlarge the stability region as much as possible. The other is how to guarantee stability when a computational time limitation exists. In this paper, a modified MPC scheme for constrained linear systems is described. An offline LMI-based iteration process is introduced to expand the stability region. At the same time, a database of feasible control sequences is generated offline so that stability can still be guaranteed in the case of computational time limitations. Simulation results illustrate the effectiveness of this new approach.

  17. Cheater identifiable visual secret sharing scheme

    Institute of Scientific and Technical Information of China (English)

    Gan Zhi; Chen Kefei

    2005-01-01

    The visual secret sharing scheme proposed by Naor and Shamir provides a way to encrypt a secret black-white image into shares. A qualified group of participants can recover the secret message without using any cryptographic computation. But the original scheme can easily be corrupted by malicious participant. We propose an extension of VSS(visual secret sharing) to identify cheaters before the secret is recovered. Without the need for any additional information and cryptographic computation, every participant can verify the validity of shares of other participants, thus the security of VSS is enhanced.

  18. The Financial Analysis of a Modern Scheme for Managing Waste Proposed for the Urban Community Arieş, Cluj County

    Directory of Open Access Journals (Sweden)

    Lucia Monica SCORȚAR

    2009-10-01

    Full Text Available This paper presents a scheme for managingwaste, proposed for the urban community of Arieş,Cluj County, in which we are going to show themain activities that should be accomplished withthe support of the local public administration.Based on the analysis of the waste flows, thedemographic trends and the waste generatingtrends, we propose a scheme for managingwaste that has a major investment component,an administrative re-organizing component andan educational one. We suggest a scheme whichincludes advanced techniques and methods fortreating waste. Moreover, we demonstrated thatthe efficiency of the scheme cannot be conceivedoutside a circuit for valorizing and recycling theuseful materials contained in the waste.

  19. Dynamic Heat Transfer Model of Refrigerated Foodstuff

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....... happens to the food inside during this period, when we look at the quality factor? This paper discusses quality model of foodstuff, different scenarios of defrost scheme are simulated, questions such as how the defrost temperature and duration influence the food temperature, thus the food quality, as well...

  20. Quality Model of Foodstuff in a Refrigerated Display Cabinet

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....... happens to the food inside during this period, when we look at the quality factor? This paper discusses quality model of foodstuff, different scenarios of defrost scheme are simulated, questions such as how the defrost temperature and duration influence the food temperature, thus the food quality, as well...

  1. Quality Model of Foodstuff in the Control of Refrigerated Display Cabinet

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....... happens to the food inside during this period, when we look at the quality factor? This paper discusses quality model of foodstuff, different scenarios of defrost scheme are simulated, questions such as how the defrost temperature and duration influence the food temperature, thus the food quality, as well...

  2. A Hash Based Remote User Authentication and Authenticated Key Agreement Scheme for the Integrated EPR Information System.

    Science.gov (United States)

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi; Wang, Chun-Cheng

    2015-11-01

    To protect patient privacy and ensure authorized access to remote medical services, many remote user authentication schemes for the integrated electronic patient record (EPR) information system have been proposed in the literature. In a recent paper, Das proposed a hash based remote user authentication scheme using passwords and smart cards for the integrated EPR information system, and claimed that the proposed scheme could resist various passive and active attacks. However, in this paper, we found that Das's authentication scheme is still vulnerable to modification and user duplication attacks. Thereafter we propose a secure and efficient authentication scheme for the integrated EPR information system based on lightweight hash function and bitwise exclusive-or (XOR) operations. The security proof and performance analysis show our new scheme is well-suited to adoption in remote medical healthcare services.

  3. Comparison of actinides and fission products recycling scheme with the normal plutonium recycling scheme in fast reactors

    Directory of Open Access Journals (Sweden)

    Salahuddin Asif

    2013-01-01

    Full Text Available Multiple recycling of actinides and non-volatile fission products in fast reactors through the dry re-fabrication/reprocessing atomics international reduction oxidation process has been studied as a possible way to reduce the long-term potential hazard of nuclear waste compared to that resulting from reprocessing in a wet PUREX process. Calculations have been made to compare the actinides and fission products recycling scheme with the normal plutonium recycling scheme in a fast reactor. For this purpose, the Karlsruhe version of isotope generation and depletion code, KORIGEN, has been modified accordingly. An entirely novel fission product yields library for fast reactors has been created which has replaced the old KORIGEN fission products library. For the purposes of this study, the standard 26 groups data set, KFKINR, developed at Forschungszentrum Karlsruhe, Germany, has been extended by the addition of the cross-sections of 13 important actinides and 68 most important fission products. It has been confirmed that these 68 fission products constitute about 95% of the total fission products yield and about 99.5% of the total absorption due to fission products in fast reactors. The amount of fissile material required to guarantee the criticality of the reactor during recycling schemes has also been investigated. Cumulative high active waste per ton of initial heavy metal is also calculated. Results show that the recycling of actinides and fission products in fast reactors through the atomics international reduction oxidation process results in a reduction of the potential hazard of radioactive waste.

  4. Proofs of Security for Improved Rabin Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    DONG Xiao-lei; LU Rong-xing; CAO Zhen-fu

    2006-01-01

    The improved RSA signature scheme can be strictly proved to be equivalent to the factoring problem. In the improved RSA signature scheme, when the public exponent e= 1, the scheme becomes the improved Rabin signature. Such an improved Rabin signature scheme is reviewed and the techniques from the provable security is applied to analyze its security.

  5. The Construction of Association Schemes by Parameter Amendment

    Institute of Scientific and Technical Information of China (English)

    Yong-lin Zhang

    2005-01-01

    Association scheme is a structure on a finite set that has some special relations among elements in the set. These relations are usually hidden in other relations, so how to derive them out is a problem. The paper gives a constructing method of mending parameters of the association schemes, and a new family of association schemes is obtained: quasi-metric association scheme.

  6. Secure Batch Verification Protocol for RSA Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    JIAZongpu; LIQingchao; LIZichen

    2005-01-01

    Harn, in 1998, proposed an efficient batch verification scheme for multiple RSA digital signatures.However, the scheme has a weakness, that is a signer can generate multiple signatures which can pass the batch verification scheme, but every one of these multiple signatures is not a valid signature. To avoid this disadvantage, we propose an improved batch verification scheme.

  7. A target coverage scheduling scheme based on genetic algorithms in directional sensor networks.

    Science.gov (United States)

    Gil, Joon-Min; Han, Youn-Hee

    2011-01-01

    As a promising tool for monitoring the physical world, directional sensor networks (DSNs) consisting of a large number of directional sensors are attracting increasing attention. As directional sensors in DSNs have limited battery power and restricted angles of sensing range, maximizing the network lifetime while monitoring all the targets in a given area remains a challenge. A major technique to conserve the energy of directional sensors is to use a node wake-up scheduling protocol by which some sensors remain active to provide sensing services, while the others are inactive to conserve their energy. In this paper, we first address a Maximum Set Covers for DSNs (MSCD) problem, which is known to be NP-complete, and present a greedy algorithm-based target coverage scheduling scheme that can solve this problem by heuristics. This scheme is used as a baseline for comparison. We then propose a target coverage scheduling scheme based on a genetic algorithm that can find the optimal cover sets to extend the network lifetime while monitoring all targets by the evolutionary global search technique. To verify and evaluate these schemes, we conducted simulations and showed that the schemes can contribute to extending the network lifetime. Simulation results indicated that the genetic algorithm-based scheduling scheme had better performance than the greedy algorithm-based scheme in terms of maximizing network lifetime.

  8. Implementation of a Cross-Layer Sensing Medium-Access Control Scheme.

    Science.gov (United States)

    Su, Yishan; Fu, Xiaomei; Han, Guangyao; Xu, Naishen; Jin, Zhigang

    2017-04-10

    In this paper, compressed sensing (CS) theory is utilized in a medium-access control (MAC) scheme for wireless sensor networks (WSNs). We propose a new, cross-layer compressed sensing medium-access control (CL CS-MAC) scheme, combining the physical layer and data link layer, where the wireless transmission in physical layer is considered as a compress process of requested packets in a data link layer according to compressed sensing (CS) theory. We first introduced using compressive complex requests to identify the exact active sensor nodes, which makes the scheme more efficient. Moreover, because the reconstruction process is executed in a complex field of a physical layer, where no bit and frame synchronizations are needed, the asynchronous and random requests scheme can be implemented without synchronization payload. We set up a testbed based on software-defined radio (SDR) to implement the proposed CL CS-MAC scheme practically and to demonstrate the validation. For large-scale WSNs, the simulation results show that the proposed CL CS-MAC scheme provides higher throughput and robustness than the carrier sense multiple access (CSMA) and compressed sensing medium-access control (CS-MAC) schemes.

  9. Energy Efficient MAC Scheme for Wireless Sensor Networks with High-Dimensional Data Aggregate

    Directory of Open Access Journals (Sweden)

    Seokhoon Kim

    2015-01-01

    Full Text Available This paper presents a novel and sustainable medium access control (MAC scheme for wireless sensor network (WSN systems that process high-dimensional aggregated data. Based on a preamble signal and buffer threshold analysis, it maximizes the energy efficiency of the wireless sensor devices which have limited energy resources. The proposed group management MAC (GM-MAC approach not only sets the buffer threshold value of a sensor device to be reciprocal to the preamble signal but also sets a transmittable group value to each sensor device by using the preamble signal of the sink node. The primary difference between the previous and the proposed approach is that existing state-of-the-art schemes use duty cycle and sleep mode to save energy consumption of individual sensor devices, whereas the proposed scheme employs the group management MAC scheme for sensor devices to maximize the overall energy efficiency of the whole WSN systems by minimizing the energy consumption of sensor devices located near the sink node. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of active time of sensor devices, transmission delay, control overhead, and energy consumption. Therefore, the proposed scheme is suitable for sensor devices in a variety of wireless sensor networking environments with high-dimensional data aggregate.

  10. AN EFFICIENT BIT COMMITMENT SCHEME BASED ON FACTORING ASSUMPTION

    Institute of Scientific and Technical Information of China (English)

    Zhong Ming; Yang Yixian

    2001-01-01

    Recently, many bit commitment schemes have been presented. This paper presents a new practical bit commitment scheme based on Schnorr's one-time knowledge proof scheme,where the use of cut-and-choose method and many random exam candidates in the protocols are replaced by a single challenge number. Therefore the proposed bit commitment scheme is more efficient and practical than the previous schemes In addition, the security of the proposed scheme under factoring assumption is proved, thus the cryptographic basis of the proposed scheme is clarified.

  11. Scheme of adaptive polarization filtering based on Kalman model

    Institute of Scientific and Technical Information of China (English)

    Song Lizhong; Qi Haiming; Qiao Xiaolin; Meng Xiande

    2006-01-01

    A new kind of adaptive polarization filtering algorithm in order to suppress the angle cheating interference for the active guidance radar is presented. The polarization characteristic of the interference is dynamically tracked by using Kalman estimator under variable environments with time. The polarization filter parameters are designed according to the polarization characteristic of the interference, and the polarization filtering is finished in the target cell. The system scheme of adaptive polarization filter is studied and the tracking performance of polarization filter and improvement of angle measurement precision are simulated. The research results demonstrate this technology can effectively suppress the angle cheating interference in guidance radar and is feasible in engineering.

  12. The European Emissions Trading Scheme case law

    NARCIS (Netherlands)

    van Zeben, J.A.W.

    2009-01-01

    Within European climate change and energy policy, the European Emissions Trading Scheme (EU ETS) occupies a prominent role. This article considers the developing case law of the European courts on the EU ETS. Specific attention is paid to the role of the different actors within the EU ETS and the im

  13. High Order Semi-Lagrangian Advection Scheme

    Science.gov (United States)

    Malaga, Carlos; Mandujano, Francisco; Becerra, Julian

    2014-11-01

    In most fluid phenomena, advection plays an important roll. A numerical scheme capable of making quantitative predictions and simulations must compute correctly the advection terms appearing in the equations governing fluid flow. Here we present a high order forward semi-Lagrangian numerical scheme specifically tailored to compute material derivatives. The scheme relies on the geometrical interpretation of material derivatives to compute the time evolution of fields on grids that deform with the material fluid domain, an interpolating procedure of arbitrary order that preserves the moments of the interpolated distributions, and a nonlinear mapping strategy to perform interpolations between undeformed and deformed grids. Additionally, a discontinuity criterion was implemented to deal with discontinuous fields and shocks. Tests of pure advection, shock formation and nonlinear phenomena are presented to show performance and convergence of the scheme. The high computational cost is considerably reduced when implemented on massively parallel architectures found in graphic cards. The authors acknowledge funding from Fondo Sectorial CONACYT-SENER Grant Number 42536 (DGAJ-SPI-34-170412-217).

  14. A Novel MBAFF Scheme of AVS

    Institute of Scientific and Technical Information of China (English)

    Jian-Wen Chen; Guo-Ping Li; Yun He

    2006-01-01

    Adaptive frame/field coding techniques have been adopted in many international video standards for interlaced sequence coding. When the frame/field adaptation is applied on the picture level, the coding efficiency is improved greatly,compared with the pure frame coding or the pure field coding. The picture-level adaptive frame/field coding (PAFF) selects frame coding or field coding once for one picture. If this frame/field adaptation is extended to Macro Block (MB) level, the coding efficiency will be further increased. In this paper, a novel MB-level adaptive frame/field (MBAFF) coding scheme is proposed. In the proposed MBAFF scheme, the top field of the current picture is used as a reference. The experiments are implemented on the platforms of Audio Video coding Standard (AVS) base profile and H.264/AVC, respectively. On the AVS platform, 0.35dB gain can be achieved averagely, compared with AVS1.0 anchor. On the H.264/AVC platform, 0.16dB gain can be achieved averagely, compared with MBAFF scheme of H.264/AVC. Additionally, an extensive subjective quality enhancement can be achieved by the proposed scheme.

  15. Labeling schemes for bounded degree graphs

    DEFF Research Database (Denmark)

    Adjiashvili, David; Rotbart, Noy Galil

    2014-01-01

    graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 2010], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 2002]. We also provide improved labeling schemes for bounded degree...

  16. Two modified discrete chirp Fourier transform schemes

    Institute of Scientific and Technical Information of China (English)

    樊平毅; 夏香根

    2001-01-01

    This paper presents two modified discrete chirp Fourier transform (MDCFT) schemes.Some matched filter properties such as the optimal selection of the transform length, and its relationship to analog chirp-Fourier transform are studied. Compared to the DCFT proposed previously, theoretical and simulation results have shown that the two MDCFTs can further improve the chirp rate resolution of the detected signals.

  17. GVD compensation schemes with considering PMD

    Institute of Scientific and Technical Information of China (English)

    Aiying Yang(杨爱英); Anshi Xu(徐安士); Deming Wu(吴德明)

    2003-01-01

    Three group velocity dispersion (GVD) compensation schemes, i.e., the post-compensation, pre-compensation and hybrid-compensation schemes, are discussed with considering polarization mode disper-sion (PMD). In the 10- and 40-Gbit/s non-return-zero (NRZ) on-off-key (OOK) systems, three physicalfactors, Kerr effect, GVD and PMD are considered. The numerical results show that, when the impactof PMD is taken into account, the GVD pre-compensation scheme performs best with more than 1 dBbetter of average eye-opening penalty (EOP) when input power is up to 10 dBm in the 10-Gbit/s system.However the GVD post-compensation scheme perforns best for the case of 40 Gbit/s with input power lessthan 13 dBm, and GVD pre-compensation will be better if the input power increased beyond this range.The results are different from those already reported under the assumption that the impact of PMD isneglected. Therefore, the research in this paper provide a different insight into the system optimizationwhen PMD, Kerr effect and GVD are considered.

  18. Optimal design of funded pension schemes

    NARCIS (Netherlands)

    Bovenberg, A.L.; Mehlkopf, R.J.

    2014-01-01

    This article reviews the literature on the optimal design and regulation of funded pension schemes. We first characterize optimal saving and investment over an individual’s life cycle. Within a stylized modeling framework, we explore optimal individual saving and investing behavior. Subsequently, va

  19. Harmonic generation with multiple wiggler schemes

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio, R.; De Salvo, L.; Pierini, P. [Universita degli Studi, Milano (Italy)

    1995-02-01

    In this paper the authors give a simple theoretical description of the basic physics of the single pass high gain free electron laser (FEL), describing in some detail the FEL bunching properties and the harmonic generation technique with a multiple-wiggler scheme or a high gain optical klystron configuration.

  20. On the Equivalence of Regularization Schemes

    Institute of Scientific and Technical Information of China (English)

    YANG Ji-Feng

    2002-01-01

    We illustrate via the sunset diagram that dimensional regularization ‘deforms' the nonlocal contentsof multi-loop diagrams with its equivalence to cutoff regularization scheme recovered only after sub-divergence wassubtracted. Then we employed a differential equation approach for calculating loop diagrams to verify that dimensionalare argued especially in nonperturbativc perspective.

  1. An Optimal Labeling Scheme for Ancestry Queries

    CERN Document Server

    Fraigniaud, Pierre

    2009-01-01

    An ancestry labeling scheme assigns labels (bit strings) to the nodes of rooted trees such that ancestry queries between any two nodes in a tree can be answered merely by looking at their corresponding labels. The quality of an ancestry labeling scheme is measured by its label size, that is the maximal number of bits in a label of a tree node. In addition to its theoretical appeal, the design of efficient ancestry labeling schemes is motivated by applications in web search engines. For this purpose, even small improvements in the label size are important. In fact, the literature about this topic is interested in the exact label size rather than just its order of magnitude. As a result, following the proposal of a simple interval-based ancestry scheme with label size $2\\log_2 n$ bits (Kannan et al., STOC '88), a considerable amount of work was devoted to improve the bound on the size of a label. The current state of the art upper bound is $\\log_2 n + O(\\sqrt{\\log n})$ bits (Abiteboul et al., SODA '02) which is...

  2. Storage System Design Scheme in Virtualization Construction

    Institute of Scientific and Technical Information of China (English)

    Si Zhen-yu

    2012-01-01

    In order to improve resource utilization, it is necessary to integrate storage and data, and the emergence of cloud computing makes it possible. This paper analyzed the study of virtualization and cloud computing, proposed a new scheme based on virtualization, and established a shared storage platform, which made a good complement and perfected the centralized storage platform.

  3. Performance Evaluation of Modified Signcryption Scheme

    Directory of Open Access Journals (Sweden)

    Bharat Gupta

    2012-12-01

    Full Text Available Before a message is sent out, the sender of the message would sign it using a digital signature scheme and then encrypt the message (and the signature use a private key encryption algorithm under a randomly chosen message encryption key. The random message encryption key would then be encrypted using the recipient's public key. We call this process two-step approach: “signature-then-encryption”. Concept signcryption, first proposed by Zheng, is a cryptography primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost and communication overhead are significantly lower than that needed by traditional signature then encryption. In Zheng’s scheme, the signature verification can be done recipient’s private key at receiverend and its security are based on mainly Discrete Logarithm Problem (DLP, reversing one way hash function. In proposed modified signcryption scheme, security is based on the intractability of three hard problems: Discrete Logarithm Problem, reversing one way hash function and to determine prime factors of a composit number. Proposed signcryption scheme has all the benefits of signcryption and is also able to resolve the dispute / problem of non repudiation by independent third party, without compromising with sender and recipient’s private keys.

  4. The EU Greenhouse Gas Emissions Trading Scheme

    NARCIS (Netherlands)

    Woerdman, Edwin; Woerdman, Edwin; Roggenkamp, Martha; Holwerda, Marijn

    2015-01-01

    This chapter explains how greenhouse gas emissions trading works, provides the essentials of the Directive on the European Union Emissions Trading Scheme (EU ETS) and summarizes the main implementation problems of the EU ETS. In addition, a law and economics approach is used to discuss the dilemmas

  5. Determinantal schemes and Buchsbaum-Rim sheaves

    CERN Document Server

    Kreuzer, M; Nagel, U; Peterson, C

    1997-01-01

    Let $\\phi$ be a generically surjective morphism between direct sums of line bundles on $\\proj{n}$ and assume that the degeneracy locus, $X$, of $\\phi$ has the expected codimension. We call $B_{\\phi} = \\ker \\phi$ a (first) Buchsbaum-Rim sheaf and we call $X$ a standard determinantal scheme. Viewing delete a generalized row from $\\phi$ and have the maximal minors of the resulting submatrix define a scheme of the expected codimension. In this paper we give several characterizations of good determinantal schemes. In particular, it is shown that being a good determinantal scheme of codimension $r+1$ is equivalent to being the zero-locus of a regular section of the dual of a first Buchsbaum-Rim sheaf of rank $r+1$. It is also equivalent to being standard determinantal and locally a complete intersection outside a subscheme $Y subscheme $X$ of codimension $r+1$ there is a good determinantal subscheme $S$ codimension $r$ such that $X$ sits in $S$ in a nice way. This leads to several generalizations of a theorem of Kr...

  6. A New Dynamic Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    HE Yefeng

    2006-01-01

    In this paper, a new dynamic group signature scheme is proposed. It allows the group manager to increase or delete group members flexibly. Furthermore, the length of group signatures, as well as the computational effort for signing, verifying and opening are very small and independent of the number of group members and deleted group members. So it is efficient.

  7. Interlaboratory comparison schemes for fibre counting: AFRICA and the WHO/EURO reference scheme

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.W.; Jones, A.D. [Institute of Occupational Medicine, Edinburgh (United Kingdom)

    2001-03-01

    Airborne fibres, particularly asbestos, can present serious risks to human health, therefore laboratories need to produce reliable measurements of their concentrations. To help achieve this, they participate in interlaboratory comparisons, in the form of national or international proficiency testing schemes for fibre counting. Two of the international schemes are the Asbestos Fibre Regular Informal Counting Arrangement (AFRICA), for asbestos fibres, and the WHO/EURO Reference Scheme, for man-made mineral fibres. Both schemes have operated since the 1980s, offering several benefits to participants. The schemes employ a method similar in principle to that of other proficiency testing programmes. Participants are rated 1 to 3 depending on how close their results are to pre-defined reference values. The majority of laboratories perform well; and in each round an average of only 3% of WHO/EURO scheme participants and 8% of AFRICA participants were rated 3 (unsatisfactory). There is also evidence that new members improve after they join the schemes. (orig.)

  8. Arbitrated quantum signature scheme based on reusable key

    Science.gov (United States)

    Yu, ChaoHua; Guo, GongDe; Lin, Song

    2014-11-01

    An arbitrated quantum signature scheme without using entangled states is proposed. In the scheme, by employing a classical hash function and random numbers, the secret keys of signer and receiver can be reused. It is shown that the proposed scheme is secure against several well-known attacks. Specifically, it can stand against the receiver's disavowal attack. Moreover, compared with previous relevant arbitrated quantum signature schemes, the scheme proposed has the advantage of less transmission complexity.

  9. Arbitrated quantum signature scheme based on reusable key

    Institute of Scientific and Technical Information of China (English)

    YU ChaoHua; GUO GongDe; LIN Song

    2014-01-01

    An arbitrated quantum signature scheme without using entangled states is proposed.In the scheme,by employing a classical hash function and random numbers,the secret keys of signer and receiver can be reused.It is shown that the proposed scheme is secure against several well-known attacks.Specifically,it can stand against the receiver's disavowal attack.Moreover,compared with previous relevant arbitrated quantum signature schemes,the scheme proposed has the advantage of less transmission complexity.

  10. Simple Numerical Schemes for the Korteweg-deVries Equation

    Energy Technology Data Exchange (ETDEWEB)

    C. J. McKinstrie; M. V. Kozlov

    2000-12-01

    Two numerical schemes, which simulate the propagation of dispersive non-linear waves, are described. The first is a split-step Fourier scheme for the Korteweg-de Vries (KdV) equation. The second is a finite-difference scheme for the modified KdV equation. The stability and accuracy of both schemes are discussed. These simple schemes can be used to study a wide variety of physical processes that involve dispersive nonlinear waves.

  11. Uplink Access Schemes for LTE-Advanced

    Science.gov (United States)

    Liu, Le; Inoue, Takamichi; Koyanagi, Kenji; Kakura, Yoshikazu

    The 3GPP LTE-Advanced has been attracting much attention recently, where the channel bandwidth would be beyond the maximum bandwidth of LTE, 20MHz. In LTE, single carrier-frequency division multiple access (SC-FDMA) was accepted as the uplink access scheme due to its advantage of very low cubic metric (CM). For LTE-A wideband transmission, multicarrier access would be more effective than single carrier access to make use of multi-user diversity and can maintain the physical channel structure of LTE, where the control information is transmitted on the edges of each 20MHz. In this paper, we discuss the access schemes in bandwidth under 20MHz as well as over 20MHz. In the case of bandwidth under 20MHz, we propose the access schemes allowing discontinuous resource allocation to enhance average throughput while maintaining cell-edge user throughput, that is, DFT-spread-OFDM with spectrum division control (SDC) and adaptive selection of SC-FDMA and OFDM (SC+OFDM). The number of discontinuous spectrums is denoted as spectrum division (SD). For DFT-S-OFDM, we define a parameter max SD as the upper limit of SD. We evaluate our proposed schemes in bandwidth under 20MHz and find that SC+OFDM as well as SDC with common max SD or UE-specific max SD can improve average throughput while their cell-edge user throughput can approach that of SC-FDMA. In the case of bandwidth over 20MHz, we consider key factors to decide a feasible access scheme for aggregating several 20MHz-wide bands.

  12. Information field dynamics for simulation scheme construction

    Science.gov (United States)

    Enßlin, Torsten A.

    2013-01-01

    Information field dynamics (IFD) is introduced here as a framework to derive numerical schemes for the simulation of physical and other fields without assuming a particular subgrid structure as many schemes do. IFD constructs an ensemble of nonparametric subgrid field configurations from the combination of the data in computer memory, representing constraints on possible field configurations, and prior assumptions on the subgrid field statistics. Each of these field configurations can formally be evolved to a later moment since any differential operator of the dynamics can act on fields living in continuous space. However, these virtually evolved fields need again a representation by data in computer memory. The maximum entropy principle of information theory guides the construction of updated data sets via entropic matching, optimally representing these field configurations at the later time. The field dynamics thereby become represented by a finite set of evolution equations for the data that can be solved numerically. The subgrid dynamics is thereby treated within auxiliary analytic considerations. The resulting scheme acts solely on the data space. It should provide a more accurate description of the physical field dynamics than simulation schemes constructed ad hoc, due to the more rigorous accounting of subgrid physics and the space discretization process. Assimilation of measurement data into an IFD simulation is conceptually straightforward since measurement and simulation data can just be merged. The IFD approach is illustrated using the example of a coarsely discretized representation of a thermally excited classical Klein-Gordon field. This should pave the way towards the construction of schemes for more complex systems like turbulent hydrodynamics.

  13. Comparative trials in registration files of cardiovascular drugs : Comparator drugs and dosing schemes.

    NARCIS (Netherlands)

    Wieringa, NF; Vos, R; de Graeff, PA

    2001-01-01

    Registration files of 13 cardiovascular drugs were analysed with respect to the number of double-blind phase-III clinical trials, the use of placebo and active comparator drugs and their dosing schemes. Half of the 146 double-blind trials used active comparator drugs. The majority of files included

  14. Efficient Relay Selection Scheme based on Fuzzy Logic for Cooperative Communication

    Directory of Open Access Journals (Sweden)

    Shakeel Ahmad Waqas

    2016-11-01

    Full Text Available The performance of cooperative network can be increased by using relay selection technique. Therefore, interest in relay selection is sloping upward. We proposed two new relay selection schemes based on fuzzy logic for dual hop cooperative communication. These relay selection schemes require SNR (signal to noise ratio, cooperative gain and channel gain as input fuzzy parameters for selection of best relay. The performance of first proposed relay selection scheme is evaluated in term of BER (bit error rate in Nakagami, Rician and Rayleigh fading channels. In second proposed relay selection scheme, threshold is used with the objective to minimize the power consumption and channel estimation load. Its performance is analyzed in term of BER, number of active relays and load of number of channel estimations.

  15. Research on a New Control Scheme of Photovoltaic Grid Power Generation System

    Directory of Open Access Journals (Sweden)

    Dong-Hui Li

    2014-01-01

    Full Text Available A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

  16. Bidirectional Partial Generalized Synchronization in Chaotic and Hyperchaotic Systems via a New Scheme

    Institute of Scientific and Technical Information of China (English)

    WANG Qi

    2006-01-01

    In this paper, a bidirectional partial generalized (lag, complete, and anticipated) synchronization of a class of continuous-time systems is defined. Then based on the active control idea, a new systematic and concrete scheme is developed to achieve bidirectional partial generalized (lag, complete, and anticipated) synchronization between two chaotic systems or between chaotic and hyperchaotic systems. With the help of symbolic-numerical computation,we choose the modified Chua system, Lorenz system, and the hyperchaotic Tamasevicius-Namajunas-Cenys system to illustrate the proposed scheme. Numerical simulations are used to verify the effectiveness of the proposed scheme. It is interesting that partialchaos synchronization not only can take place between two chaotic systems, but also can take place between chaotic and hyperchaotic systems. The proposed scheme can also be extended to research bidirectional partial generalized (lag, complete, and anticipated) synchronization between other dynamical systems.

  17. A classification scheme for risk assessment methods.

    Energy Technology Data Exchange (ETDEWEB)

    Stamp, Jason Edwin; Campbell, Philip LaRoche

    2004-08-01

    This report presents a classification scheme for risk assessment methods. This scheme, like all classification schemes, provides meaning by imposing a structure that identifies relationships. Our scheme is based on two orthogonal aspects--level of detail, and approach. The resulting structure is shown in Table 1 and is explained in the body of the report. Each cell in the Table represent a different arrangement of strengths and weaknesses. Those arrangements shift gradually as one moves through the table, each cell optimal for a particular situation. The intention of this report is to enable informed use of the methods so that a method chosen is optimal for a situation given. This report imposes structure on the set of risk assessment methods in order to reveal their relationships and thus optimize their usage.We present a two-dimensional structure in the form of a matrix, using three abstraction levels for the rows and three approaches for the columns. For each of the nine cells in the matrix we identify the method type by name and example. The matrix helps the user understand: (1) what to expect from a given method, (2) how it relates to other methods, and (3) how best to use it. Each cell in the matrix represent a different arrangement of strengths and weaknesses. Those arrangements shift gradually as one moves through the table, each cell optimal for a particular situation. The intention of this report is to enable informed use of the methods so that a method chosen is optimal for a situation given. The matrix, with type names in the cells, is introduced in Table 2 on page 13 below. Unless otherwise stated we use the word 'method' in this report to refer to a 'risk assessment method', though often times we use the full phrase. The use of the terms 'risk assessment' and 'risk management' are close enough that we do not attempt to distinguish them in this report. The remainder of this report is organized as follows. In

  18. Scheme for Quantum Computing Immune to Decoherence

    Science.gov (United States)

    Williams, Colin; Vatan, Farrokh

    2008-01-01

    A constructive scheme has been devised to enable mapping of any quantum computation into a spintronic circuit in which the computation is encoded in a basis that is, in principle, immune to quantum decoherence. The scheme is implemented by an algorithm that utilizes multiple physical spins to encode each logical bit in such a way that collective errors affecting all the physical spins do not disturb the logical bit. The scheme is expected to be of use to experimenters working on spintronic implementations of quantum logic. Spintronic computing devices use quantum-mechanical spins (typically, electron spins) to encode logical bits. Bits thus encoded (denoted qubits) are potentially susceptible to errors caused by noise and decoherence. The traditional model of quantum computation is based partly on the assumption that each qubit is implemented by use of a single two-state quantum system, such as an electron or other spin-1.2 particle. It can be surprisingly difficult to achieve certain gate operations . most notably, those of arbitrary 1-qubit gates . in spintronic hardware according to this model. However, ironically, certain 2-qubit interactions (in particular, spin-spin exchange interactions) can be achieved relatively easily in spintronic hardware. Therefore, it would be fortunate if it were possible to implement any 1-qubit gate by use of a spin-spin exchange interaction. While such a direct representation is not possible, it is possible to achieve an arbitrary 1-qubit gate indirectly by means of a sequence of four spin-spin exchange interactions, which could be implemented by use of four exchange gates. Accordingly, the present scheme provides for mapping any 1-qubit gate in the logical basis into an equivalent sequence of at most four spin-spin exchange interactions in the physical (encoded) basis. The complexity of the mathematical derivation of the scheme from basic quantum principles precludes a description within this article; it must suffice to report

  19. Improvement of Mixing Function for Modified Upwinding Compact Scheme

    CERN Document Server

    Fu, Huankun; Liu, Chaoqun

    2014-01-01

    The compact scheme has high order accuracy and high resolution, but cannot be used to capture the shock. WENO is a great scheme for shock capturing, but is too dissipative for turbulence and small length scales. We developed a modified upwinding compact scheme which uses an effective shock detector to block compact scheme to cross the shock and a control function to mix the flux with WENO scheme near the shock. The new scheme makes the original compact scheme able to capture the shock sharply and, more important, keep high order accuracy and high resolution in the smooth area, which is particularly important for shock boundary layer and shock acoustic interactions. This work is a continuation to modify the control function for the modified up-winding compact scheme (MUCS). Numerical results show the scheme is successful for 2-D Euler.

  20. PERTURBATIONAL FINITE DIFFERENCE SCHEME OF CONVECTION-DIFFUSION EQUATION

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Perturbational Finite Difference (PFD) method is a kind of high-order-accurate compact difference method, But its idea is different from the normal compact method and the multi-nodes method. This method can get a Perturbational Exact Numerical Solution (PENS) scheme for locally linearlized Convection-Diffusion (CD) equation. The PENS scheme is similar to the Finite Analytical (FA) scheme and Exact Difference Solution (EDS) scheme, which are all exponential schemes, but PENS scheme is simpler and uses only 3, 5 and 7 nodes for 1-, 2- and 3-dimensional problems, respectively. The various approximate schemes of PENS scheme are also called Perturbational-High-order-accurate Difference (PHD) scheme. The PHD schemes can be got by expanding the exponential terms in the PENS scheme into power series of grid Renold number, and they are all upwind schemes and remain the concise structure form of first-order upwind scheme. For 1-dimensional (1-D) CD equation and 2-D incompressible Navier-Stokes equation, their PENS and PHD schemes were constituted in this paper, they all gave highly accurate results for the numerical examples of three 1-D CD equations and an incompressible 2-D flow in a square cavity.

  1. A novel cell search scheme for OFDM cellular systems

    Institute of Scientific and Technical Information of China (English)

    DING Ming; LUO Han-wen; WU Yun

    2007-01-01

    A novel cell search scheme for OFDM cellular systems is proposed. It is based on one OFDM symbol with several identical slots as preamble, the time domain repetition structure of which can be utilized to accomplish OFDM timing/frequency synchronization. The cell ID is comprised of two parts: a sub-carrier mask index g and a sequence index x. Each sub-carrier mask activates or deactivates some of the sub-carriers, after which a differentially coded sequence is loaded on pairs of the adjacent active sub-carriers. The user equipment (UE) recognizes the mask with index g via power detection of the received frequency domain signal. Then it estimates the index x from differential demodulation followed by detection of the frequency domain sequence. In order to improve the performance, a method of jointly estimating g and x is devised. Simulation results showed that the proposed scheme is able to support a very large number of cell IDs while maintaining a good performance even in bad multi-cell environment.

  2. Fuzzy Logic Controller Scheme for Floor Vibration Control

    Directory of Open Access Journals (Sweden)

    Nyawako Donald Steve

    2015-01-01

    Full Text Available The design of civil engineering floors is increasingly being governed by their vibration serviceability performance. This trend is the result of advancements in design technologies offering designers greater flexibilities in realising more lightweight, longer span and more open-plan layouts. These floors are prone to excitation from human activities. The present research work looks at analytical studies of active vibration control on a case study floor prototype that has been specifically designed to be representative of a real office floor structure. Specifically, it looks at tuning fuzzy control gains with the aim of adapting them to measured structural responses under human excitation. Vibration mitigation performances are compared with those of a general velocity feedback controller, and these are found to be identical in these sets of studies. It is also found that slightly less control force is required for the fuzzy controller scheme at moderate to low response levels and as a result of the adaptive gain, at very low responses the control force is close to zero, which is a desirable control feature. There is also saturation in the peak gain with the fuzzy controller scheme, with this gain tending towards the optimal feedback gain of the direct velocity feedback (DVF at high response levels for this fuzzy design.

  3. An asymptotic preserving scheme for P1 model using classical diffusion schemes on unstructured polygonal meshes

    Directory of Open Access Journals (Sweden)

    Navaro Pierre

    2011-11-01

    Full Text Available A new scheme for discretizing the P1 model on unstructured polygonal meshes is proposed. This scheme is designed such that its limit in the diffusion regime is the MPFA-O scheme which is proved to be a consistent variant of the Breil-Maire diffusion scheme. Numerical tests compare this scheme with a derived GLACE scheme for the P1 system. Un nouveau schéma de discrétisation du modèle P1 sur maillage non structuré composé de polygones est proposé. Ce schéma est construit pour que sa limite en régime diffusion soit le schéma MPFA-O qu’on démontre être une variante consistante du schéma de diffusion de Breil-Maire. Ce schéma est comparé sur des cas tests avec un schéma dérivé du schéma GLACE pour le modèle P1.

  4. Exclusion from the Health Insurance Scheme

    CERN Multimedia

    2003-01-01

    A CERN pensioner, member of the Organization's Health Insurance Scheme (CHIS), recently provided fake documents in support of claims for medical expenses, in order to receive unjustified reimbursement from the CHIS. The Administrator of the CHIS, UNIQA, suspected a case of fraud: Accordingly, an investigation and interview of the person concerned was carried out and brought the Organization to the conclusion that fraud had actually taken place. Consequently and in accordance with Article VIII 3.12 of the CHIS Rules, it was decided to exclude this member permanently from the CHIS. The Organization takes the opportunity to remind Scheme members that any fraud or attempt to fraud established within the framework of the CHIS exposes them to: - disciplinary action, according to the Staff Rules and Regulations, for CERN members of the personnel; - definitive exclusion from the CHIS for members affiliated on a voluntary basis. Human Resources Division Tel. 73635

  5. Cartesian Grid Method for Gas Kinetic Scheme

    CERN Document Server

    Chen, Songze; Li, Zhihui

    2015-01-01

    A Cartesian grid method combined with a simplified gas kinetic scheme is presented for subsonic and supersonic viscous flow simulation on complex geometries. Under the Cartesian mesh, the computational grid points are classified into four different categories, the fluid point, the solid point, the drop point, and the interpolation point. The boundaries are represented by a set of direction-oriented boundary points. A constrained weighted least square method is employed to evaluate the physical quantities at the interpolation points. Different boundary conditions, including isothermal boundary, adiabatic boundary, and Euler slip boundary, are presented by different interpolation strategies. We also propose a simplified gas kinetic scheme as the flux solver for both subsonic and supersonic flow computations. The methodology of constructing a simplified kinetic flux function can be extended to other flow systems. A few numerical examples are used to validate the Cartesian grid method and the simplified flux func...

  6. Fixed Wordsize Implementation of Lifting Schemes

    Directory of Open Access Journals (Sweden)

    Tanja Karp

    2007-01-01

    Full Text Available We present a reversible nonlinear discrete wavelet transform with predefined fixed wordsize based on lifting schemes. Restricting the dynamic range of the wavelet domain coefficients due to a fixed wordsize may result in overflow. We show how this overflow has to be handled in order to maintain reversibility of the transform. We also perform an analysis on how large a wordsize of the wavelet coefficients is needed to perform optimal lossless and lossy compressions of images. The scheme is advantageous to well-known integer-to-integer transforms since the wordsize of adders and multipliers can be predefined and does not increase steadily. This also results in significant gains in hardware implementations.

  7. Hedge algorithm and Dual Averaging schemes

    CERN Document Server

    Baes, Michel

    2011-01-01

    We show that the Hedge algorithm, a method that is widely used in Machine Learning, can be interpreted as a particular instance of Dual Averaging schemes, which have recently been introduced by Nesterov for regret minimization. Based on this interpretation, we establish three alternative methods of the Hedge algorithm: one in the form of the original method, but with optimal parameters, one that requires less a priori information, and one that is better adapted to the context of the Hedge algorithm. All our modified methods have convergence results that are better or at least as good as the performance guarantees of the vanilla method. In numerical experiments, our methods significantly outperform the original scheme.

  8. Evaluating Parsing Schemes with Entropy Indicators

    CERN Document Server

    Lyon, C; Lyon, Caroline; Brown, Stephen

    1997-01-01

    This paper introduces an objective metric for evaluating a parsing scheme. It is based on Shannon's original work with letter sequences, which can be extended to part-of-speech tag sequences. It is shown that this regular language is an inadequate model for natural language, but a representation is used that models language slightly higher in the Chomsky hierarchy. We show how the entropy of parsed and unparsed sentences can be measured. If the entropy of the parsed sentence is lower, this indicates that some of the structure of the language has been captured. We apply this entropy indicator to support one particular parsing scheme that effects a top down segmentation. This approach could be used to decompose the parsing task into computationally more tractable subtasks. It also lends itself to the extraction of predicate/argument structure.

  9. Employee Share Option Scheme And Employees’ Motivation

    Directory of Open Access Journals (Sweden)

    Rebecca Yew Ming Yian

    2011-06-01

    Full Text Available Employee stock options scheme (ESOS is a call option on the ordinary share of a company, issued as a form of non-cash compensation or as an incentive tool. ESOS gives an employee the right to buy shares at a fixed price for a defined number of years into the future. The trend toward broad-based share options may come to an end as companies are scaling back due to the changes in accounting standards. Similarly, companies in Malaysia, especially in the banking industry which originally offered share options to their employees are now pulling back this scheme. Does the movement to scale back share options affect employees’ motivation? This is an empirical question which this paper intends to explore. It is hope that the commercial banks will reconsider offering ESOS in rewarding their employees if the research finding indicates that it plays a significant role in motivating employees.

  10. Integrating Standard Dependency Schemes in QCSP Solvers

    Institute of Scientific and Technical Information of China (English)

    Ji-Wei Jin; Fei-Fei Ma; Jian Zhang

    2012-01-01

    Quantified constraint satisfaction problems (QCSPs) are an extension to constraint satisfaction problems (CSPs) with both universal quantifiers and existential quantifiers.In this paper we apply variable ordering heuristics and integrate standard dependency schemes in QCSP solvers.The technique can help to decide the next variable to be assigned in QCSP solving.We also introduce a new factor into the variable ordering heuristics:a variable's dep is the number of variables depending on it.This factor represents the probability of getting more candidates for the next variable to be assigned.Experimental results show that variable ordering heuristics with standard dependency schemes and the new factor dep can improve the performance of QCSP solvers.

  11. INTERLEAVING SCHEME FOR MULTICARRIER CDMA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Shi Feng; Cheng Shixin

    2004-01-01

    In MultiCarrier Code-Division Multiple-Access (MC-CDMA) system, the received signals scattered in the frequency domain are combined to get frequency diversity gain. However, the frequency diversity gain is limited because of correlation between subcarriers. A novel interleaving scheme for MC-CDMA system is proposed in this paper. A circular shifting register is introduced into each subcarrier branch to decrease the correlation between subcarriers. By using interleaving, frequency diversity gain of system is increased. System structure and model with interleaver are discussed. In the case of multiple users, Parallel Interference Cancellation (PIC) technique is also introduced. Computer simulations demonstrate the performance of proposed scheme, and the performance comparison of MC-CDMA with interleaver and conventional MC-CDMA system is shown as well.

  12. OPERATIONAL MODAL ANALYSIS SCHEMES USING CORRELATION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Zheng Min; Shen Fan; Chen Huaihai

    2005-01-01

    For some large-scale engineering structures in operating conditions, modal parameters estimation must base itself on response-only data. This problem has received a considerable amount of attention in the past few years. It is well known that the cross-correlation function between the measured responses is a sum of complex exponential functions of the same form as the impulse response function of the original system. So this paper presents a time-domain operating modal identification global scheme and a frequency-domain scheme from output-only by coupling the cross-correlation function with conventional modal parameter estimation. The outlined techniques are applied to an airplane model to estimate modal parameters from response-only data.

  13. Optimization of Train Trip Package Operation Scheme

    Directory of Open Access Journals (Sweden)

    Lu Tong

    2015-01-01

    Full Text Available Train trip package transportation is an advanced form of railway freight transportation, realized by a specialized train which has fixed stations, fixed time, and fixed path. Train trip package transportation has lots of advantages, such as large volume, long distance, high speed, simple forms of organization, and high margin, so it has become the main way of railway freight transportation. This paper firstly analyzes the related factors of train trip package transportation from its organizational forms and characteristics. Then an optimization model for train trip package transportation is established to provide optimum operation schemes. The proposed model is solved by the genetic algorithm. At last, the paper tests the model on the basis of the data of 8 regions. The results show that the proposed method is feasible for solving operation scheme issues of train trip package.

  14. Verifiable threshold signature schemes against conspiracy attack

    Institute of Scientific and Technical Information of China (English)

    甘元驹

    2004-01-01

    In this study, the author has designed new verifiable (t, n) threshold untraceable signature schemes. The proposed schemes have the following properties: ( 1 ) Verification: The shadows of the secret distributed by the trusted center can be verified by all of the participants; (2) Security: Even if the number of the dishonest member is over the value of the threshold, they cannot get the system secret parameters , such as the group secret key, and forge other member's individual signature; (3) Efficient verification: The verifier can verify the group signature easily and the verification time of the group signature is equivalent to that of an individual signature; (4) Untraceability: The signers of the group signature cannot be traced.

  15. Verifiable threshold signature schemes against conspiracy attack

    Institute of Scientific and Technical Information of China (English)

    GAN Yuan-ju(甘元驹)

    2004-01-01

    In this study, the author has designed new verifiable (t,n) threshold untraceable signature schemes. The proposed schemes have the following properties:(1) Verification: The shadows of the secret distributed by the trusted center can be verified by all of the participants;(2) Security: Even if the number of the dishonest member is over the value of the threshold, they cannot get the system secret parameters ,such as the group secret key, and forge other member's individual signature;(3) Efficient verification: The verifier can verify the group signature easily and the verification time of the group signature is equivalent to that of an individual signature; (4) Untraceability: The signers of the group signature cannot be traced.

  16. Finite volume schemes for Boussinesq type equations

    OpenAIRE

    2011-01-01

    6 pages, 2 figures, 18 references. Published in proceedings of Colloque EDP-Normandie held at Caen (France), on 28 & 29 October 2010. Other author papers can be dowloaded at http://www.lama.univ-savoie.fr/~dutykh/; Finite volume schemes are commonly used to construct approximate solutions to conservation laws. In this study we extend the framework of the finite volume methods to dispersive water wave models, in particular to Boussinesq type systems. We focus mainly on the application of the m...

  17. Finite volume schemes for Boussinesq type equations

    CERN Document Server

    Dutykh, Denys; Mitsotakis, Dimitrios

    2011-01-01

    Finite volume schemes are commonly used to construct approximate solutions to conservation laws. In this study we extend the framework of the finite volume methods to dispersive water wave models, in particular to Boussinesq type systems. We focus mainly on the application of the method to bidirectional nonlinear, dispersive wave propagation in one space dimension. Special emphasis is given to important nonlinear phenomena such as solitary waves interactions.

  18. Mapped tent pitching schemes for hyperbolic systems

    OpenAIRE

    Gopalakrishnan, J; Schöberl, J.; Wintersteiger, C.

    2016-01-01

    A spacetime domain can be progressively meshed by tent shaped objects. Numerical methods for solving hyperbolic systems using such tent meshes to advance in time have been proposed previously. Such schemes have the ability to advance in time by different amounts at different spatial locations. This paper explores a technique by which standard discretizations, including explicit time stepping, can be used within tent-shaped spacetime domains. The technique transforms the equations within a spa...

  19. Communication Scheme via Cascade Chaotic Systems

    Institute of Scientific and Technical Information of China (English)

    HUA Chang-Chun; GUAN Xin-Ping

    2004-01-01

    @@ A new chaotic communication scheme is constructed. Different from the existing literature, cascade chaotic systems are employed. Two cascade modes are considered. First, we investigate the input to state cascade mode;cascade systems between different kinds of chaotic systems are considered. Then the parameter cascade case of chaotic system is studied. Under the different cases, the corresponding receivers are designed, which can succeed in recovering the former emitted signal. Simulations are performed to verify the validity of the proposed main results.

  20. New Financing Schemes of Public Infrastructure

    OpenAIRE

    Ignacio de la Riva

    2017-01-01

    Public works procurements and concessions are traditional legal techniques used to shape the financing of public infrastructure. Fiscal constraints faced by public administrations at the end of the 20th century, and the subsequent increase of private participation in the provision of public goods and services, encouraged the development of new legal schemes allowing a higher degree of private investment in public infrastructure; such as Public Private Partnerships, project finance, securitiza...

  1. Efficient Identity Based Public Verifiable Signcryption Scheme

    OpenAIRE

    Kushwah, Prashant; Lal, Sunder

    2011-01-01

    Signcryption is a cryptographic primitive which performs encryption and signature in a single logical step. In conventional signcryption only receiver of the signcrypted text can verify the authenticity of the origin i.e. signature of the sender on the message after decrypting the cipher text. In public verifiable signcryption scheme anyone can verify the authenticity of the origin who can access the signcrypted text i.e. signature of the sender on the cipher text. Public verifiable signcrypt...

  2. A Note on Threshold Schemes with Disenrollment

    Science.gov (United States)

    2003-01-01

    Lecture Notes in Computer Science 2384, pp. 71- 88, 2002. [2] G. R. Blakley, “Safeguarding cryptographic keys,” Proc. AFIPS 1979 National Computer...CRYPTO’92, E. F. Brickell, ed., Lecture Notes in Computer Science vol. 740, pp. 540-548, 1993. [4] C. Blundo, A. Cresti, A. De Santis, U. Vaccaro...Fully dynamic secret sharing schemes,” Advances in Cryptology – CRYPTO ’93, D. R. Stinson, ed., Lecture Notes in Computer Science

  3. Traditional and Truncation schemes for Different Multiplier

    Directory of Open Access Journals (Sweden)

    Yogesh M. Motey

    2013-03-01

    Full Text Available A rapid and proficient in power requirement multiplier is always vital in electronics industry like DSP, image processing and ALU in microprocessors. Multiplier is such an imperative block w ith respect to power consumption and area occupied in the system. In order to meet the demand for high speed, various parallel array multiplication algorithms have been proposed by a number of authors. The array multipliers use a large amount of hardware, consequently consuming a large amount of power. One of the methods for multiplication is based on Indian Vedic mathematics. The total Vedic mathematics is based on sixteen sutras (word formulae and manifests a merged structure of mathematics. The parallel multipliers for example radix 2 and radix 4 booth multiplier does the computations using less number of adders and less number of iterative steps that results in, they occupy less space to that of serial multiplier. Truncated multipliers offer noteworthy enhancements in area, delay, and power. Truncated multiplication provides different method for reducing the power dissipation and area of rounded parallel multipliers in DSP systems. Since in a truncated multiplier the x less significant bits of the full-width product are discarded thus partial products are removed and replaced by a suit- able compensation equations, match the accuracy with hardware cost. A pseudo-carry compensation truncation (PCT scheme, it is for the multiplexer based array multiplier, which yields less average error among existing truncation methods.After studying many research papers it’s found that some of the schemes for multiplier are suitable because their own uniqueness of multiplication. Such schemes are listed in this paper for example the different truncation schemes like constant-correction truncation (CCT, variable -correction truncation (VCT, pseudo-carry compensation truncation (PCT are most suitable for truncated multiplier.

  4. Efficient Scheme for Chemical Flooding Simulation

    Directory of Open Access Journals (Sweden)

    Braconnier Benjamin

    2014-07-01

    Full Text Available In this paper, we investigate an efficient implicit scheme for the numerical simulation of chemical enhanced oil recovery technique for oil fields. For the sake of brevity, we only focus on flows with polymer to describe the physical and numerical models. In this framework, we consider a black oil model upgraded with the polymer modeling. We assume the polymer only transported in the water phase or adsorbed on the rock following a Langmuir isotherm. The polymer reduces the water phase mobility which can change drastically the behavior of water oil interfaces. Then, we propose a fractional step technique to resolve implicitly the system. The first step is devoted to the resolution of the black oil subsystem and the second to the polymer mass conservation. In such a way, jacobian matrices coming from the implicit formulation have a moderate size and preserve solvers efficiency. Nevertheless, the coupling between the black-oil subsystem and the polymer is not fully resolved. For efficiency and accuracy comparison, we propose an explicit scheme for the polymer for which large time step is prohibited due to its CFL (Courant-Friedrichs-Levy criterion and consequently approximates accurately the coupling. Numerical experiments with polymer are simulated : a core flood, a 5-spot reservoir with surfactant and ions and a 3D real case. Comparisons are performed between the polymer explicit and implicit scheme. They prove that our polymer implicit scheme is efficient, robust and resolves accurately the coupling physics. The development and the simulations have been performed with the software PumaFlow [PumaFlow (2013 Reference manual, release V600, Beicip Franlab].

  5. A Scheme of Controlled Quantum State Swapping

    Institute of Scientific and Technical Information of China (English)

    查新未; 邹志纯; 祁建霞; 朱海洋

    2012-01-01

    A scheme for controlled quantum state swapping is presented using maximally entangled five-qubit state, i.e., Alice wants to transmit an entangled state of particle a to Bob and at the same time Bob wants to transmit an entangled state of particle b to Alice via the control of the supervisor Charlie. The operations used in this swapping process including C-not operation and a series of single-qubit measurements performed by Alice. Bob. and Charlie.

  6. Droop Scheme With Consideration of Operating Costs

    DEFF Research Database (Denmark)

    Nutkani, I. U.; Loh, Poh Chiang; Blaabjerg, Frede

    2014-01-01

    considered even though they are different for different types of DGs. This letter thus proposes an alternative droop scheme, which can better distinguish the different operating characteristics and objectives of the DGs grouped together in a weighted droop expression. The power sharing arrived in the steady...... state will meet the intended objectives, as demonstrated in the experiment with a defined objective of minimizing the total microgrid operating cost....

  7. Log-scaling magnitude modulated watermarking scheme

    Institute of Scientific and Technical Information of China (English)

    LING HeFei; YUAN WuGang; ZOU FuHao; LU ZhengDing

    2007-01-01

    A real-time watermarking scheme with high robustness and security has been proposed based on modulating the log-scaling magnitudes of DCT coefficients,which is most suitable for JPEG images and MPEG streams. The watermark bit is encoded as the sign of the difference between the individual log-scaling magnitude of a group-region and the average one of all group-regions. The log-scaling magnitude can be modulated by modifying the low and middle frequency DCT coefficients imperceptibly. The robustness of scheme is not only dependent on those largest coefficients, but also on the other coefficients with the same proportion. It can embed 512 bits into an image with a size of 512×512, which can satisfy the payload requirement of most video watermarking applications. Moreover, the watermark embedding process only requires one-sixth of the time consumed during normal playing of video, and the watermark detection only requires one-twelfth of that, which can meet the real-time requirements of most video watermarking applications. Furthermore, the experimental results show that the presented scheme is transparent and robust to significant valumetric distortions (including additive noise, low-pass filtering, lossy compression and valumetric scaling) and a part of geometric distortions. It performs much better than the EMW algorithm in resisting all kinds of distortions except Gaussian noise with a larger deviation.

  8. Lower Bound for Visual Cryptography Schemes

    CERN Document Server

    Cheraghi, Abbas

    2007-01-01

    For a given visual cryptography scheme, it is possible to present a basis matrices for it and most of constructions are based on basis matrices. In this paper we introduce a lower bound for the pixel expansion of visual cryptography schemes with basis matrices. To make the main theorem more flexible, we will introduce a lower bound based on induced matchings of hypergraph of qualified sets. As an application, we present an algebraic proof for the fact that the pixel expansion of basis matrices of any $k$ out of $k$ scheme is at least $2^{k-1}$. In the sequel, we present a lower bound for the pixel expansion of a given graph access structure in term of maximum number of edges in an induced matching. Finally, we show that the minimum pixel expansion of basis matrices of graph access structure $P_n$ is exactly $\\lceil \\frac{n+1}{2}\\rceil$ and this shows the lower bound mentioned in the main theorem is sharp.

  9. INFORMATION FROM THE CERN HEALTH INSURANCE SCHEME

    CERN Multimedia

    Tel : 7-3635

    2002-01-01

    Please note that, from 1 July 2002, the tariff agreement between CERN and the Hôpital de la Tour will no longer be in force. As a result the members of the CERN Health Insurance Scheme will no longer obtain a 5% discount for quick payment of bills. More information on the termination of the agreement and the implications for our Health Insurance Scheme will be provided in the next issue of the CHIS Bull', due for publication in the first half of July. It will be sent to your home address, so, if you have moved recently, please check that your divisional secretariat has your current address. Tel.: 73635 The Organization's Health Insurance Scheme (CHIS) has launched its own Web pages, located on the Website of the Social & Statutory Conditions Group of HR Division (HR-SOC). The address is short and easy-to-remember www.cern.ch/chis The pages currently available concentrate on providing basic information. Over the coming months it is planned to fill out the details and introduce new topics. Please give us ...

  10. Generalized support varieties for finite group schemes

    CERN Document Server

    Friedlander, Eric M

    2011-01-01

    We construct two families of refinements of the (projectivized) support variety of a finite dimensional module $M$ for a finite group scheme $G$. For an arbitrary finite group scheme, we associate a family of {\\it non maximal rank varieties} $\\Gamma^j(G)_M$, $1\\leq j \\leq p-1$, to a $kG$-module $M$. For $G$ infinitesimal, we construct a finer family of locally closed subvarieties $V^{\\ul a}(G)_M$ of the variety of one parameter subgroups of $G$ for any partition $\\ul a$ of $\\dim M$. For an arbitrary finite group scheme $G$, a $kG$-module $M$ of constant rank, and a cohomology class $\\zeta$ in $\\HHH^1(G,M)$ we introduce the {\\it zero locus} $Z(\\zeta) \\subset \\Pi(G)$. We show that $Z(\\zeta)$ is a closed subvariety, and relate it to the non-maximal rank varieties. We also extend the construction of $Z(\\zeta)$ to an arbitrary extension class $\\zeta \\in \\Ext^n_G(M,N)$ whenever $M$ and $N$ are $kG$-modules of constant Jordan type.

  11. SINGLE TONE JAMMING ELIMINATION SCHEME OF MULTICARRIER SPREAD SPECTRUM SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Ying Xiaofan; Chu Zhenyong; Tian Hongxin; Yi Kechu

    2004-01-01

    The proposed scheme is based on Discrete Fourier Transform (DFT) domain processing. The key technology of this scheme is jamming parameters' accurate estimation and jamming reconstruction. Compared with the "threshold exciser" schemeithe proposed scheme can eliminate more jamming energy on the whole frequency band with the minimum loss of useful signal energy. As shown in the research and simulation, the proposed scheme is much better than the "threshold exciser" scheme, especially in the case of high power jamming whereas the "threshold exciser" scheme might be invalid.

  12. Cryptanalytic Performance Appraisal of Improved CCH2 Proxy Multisignature Scheme

    Directory of Open Access Journals (Sweden)

    Raman Kumar

    2014-01-01

    Full Text Available Many of the signature schemes are proposed in which the t out of n threshold schemes are deployed, but they still lack the property of security. In this paper, we have discussed implementation of improved CCH1 and improved CCH2 proxy multisignature scheme based on elliptic curve cryptosystem. We have represented time complexity, space complexity, and computational overhead of improved CCH1 and CCH2 proxy multisignature schemes. We have presented cryptanalysis of improved CCH2 proxy multisignature scheme and showed that improved CCH2 scheme suffered from various attacks, that is, forgery attack and framing attack.

  13. Constructing of constraint preserving scheme for Einstein equations

    CERN Document Server

    Tsuchiya, Takuya

    2016-01-01

    We propose a new numerical scheme of evolution for the Einstein equations using the discrete variational derivative method (DVDM). We derive the discrete evolution equation of the constraint using this scheme and show the constraint preserves in the discrete level. In addition, to confirm the numerical stability using this scheme, we perform some numerical simulations by discretized equations with the Crank-Nicolson scheme and with the new scheme, and we find that the new discretized equations have better stability than that of the Crank-Nicolson scheme.

  14. Satisfaction with the level and type of resource use of a health insurance scheme in Nigeria: health management organizations' perspectives.

    Science.gov (United States)

    Mohammed, Shafiu; Souares, Aurelia; Lorenzo Bermejo, Justo; Babale, Sufiyan Muawiyyah; Sauerborn, Rainer; Dong, Hengjin

    2014-01-01

    Some developing countries have incorporated managed care elements into their national health insurance schemes. In practice, hybrid health management organizations (Hmos) are insurers who, bearing some resemblance to managed care in the USA, are vertically integrated in the scheme's revenue collection and pool and purchase healthcare services within a competitive framework. To date, few studies have focused on these organizations and their level of satisfaction with the scheme's optimal-resource-use (ORU) implementation. In Nigeria, the study site, Hmos were categorized on the basis of their satisfaction with ORU activities. One hundred forty-seven Hmo staff were randomly interviewed. The types of ORU domain categories were provider payment mechanism, administrative efficiency, benefit package inclusions and active monitoring mechanism. Bivariate analysis was used to determine differences among the Hmos' satisfaction with the various ORU domains. The Hmos' satisfaction with the health insurance scheme's ORU activities was 59.2% generally, and the associated factors were identified. According to the Hmos' perspectives related to the type of ORU, the fee-for-service payment method and regular inspection performed weakly. Hmos' limited satisfaction with the scheme's ORU raises concerns regarding ineffectiveness that may hinder implementation. To offset high risks in the scheme, it appears necessary for the regulatory agency to adapt and reform strategies of provider payment and active monitoring mechanisms according to stakeholder needs. Our findings further reveal that having Hmos evaluate ORU is useful for providing evidence-based information for policy making and regulatory utilization related to implementation of the health insurance scheme.

  15. Location and Pressures Change Prediction of Bromo Volcano Magma Chamber Using Inversion Scheme

    Science.gov (United States)

    Kumalasari, Ratih; Srigutomo, Wahyu

    2016-08-01

    Bromo volcano is one of active volcanoes in Indonesia. It has erupted at least 50 times since 1775 and has been monitored by Global Positioning System (GPS) since 1989. We applied the Levenberg-Marquardt inversion scheme to estimate the physical parameters contributing to the surface deformation. Physical parameters obtained by the inversion scheme such as magma chamber location and volume change are useful in monitoring and predicting the activity of Bromo volcano. From our calculation it is revealed that the depth of the magma chamber d = 6307.6 m, radius of magma chamber α = 1098.6 m and pressure change ΔP ≈ 1.0 MPa.

  16. 基于在线学习和ADRC的发电机励磁与汽门系统ANN逆鲁棒控制方法%An online learning and active disturbance rejection control-based ANN-inversion robust control scheme of excitation and valve system for turbogenerator

    Institute of Scientific and Technical Information of China (English)

    徐庆宏; 黄家才; 李宏胜

    2012-01-01

    为提高汽轮发电机组励磁与汽门系统机端电压和功角的控制性能,提出了基于在线学习和自抗扰控制( ADRC)的神经网络逆鲁棒控制方法.首先,将神经网络逆(ANN)与被控励磁汽门系统组成的复合伪线性系统等效为含有扰动的线性系统;然后,基于ADRC,设计了用于在线估计复合伪线性系统状态和扰动的ESO,解决了神经网络逆在线学习时训练样本获取的难题,并在设计的伪控制量中对扰动进行补偿,基于线性系统理论证明了ESO的收敛性并针对励磁子系统和汽门子系统与神经网络逆系统组成的伪线性复合系统分别设计整数阶PID控制器和分数阶PID控制器以实现闭环控制;同时,在离线训练的基础上设计了基于在线梯度方法的神经网络逆在线学习算法,利用李雅普诺夫稳定性理论证明了神经网络逆在线学习的收敛性.最后,以典型的两区域四机系统为例进行数值仿真,与传统的AVR/PSS和基于离线训练的神经网络逆控制方法的比较结果表明所提方法明显提升了电力系统的暂态性能.%To improve the performance of the terminal voltage and power angle of the turbogenerator, an online learning and active disturbance rejection control (ADRC) based ANN-inversion (ANNI) robust control scheme was proposed. Firstly, the composite pseudo linear system, which is composed of the ANNI system and the controlled excitation and valve system, is equivalent to a linear system with disturbance. Then, an ESO was designed based on the ADRC method to estimate the states and the disturbance of the composite pseudo linear system online, in order to resolve the difficulty of online acquisition of training samples for the online learning of ANN inversion, and the pseudo control input with disturbance compensation was designed for the composite pseudo-linear system. Furthermore, the convergence of the ESO was proved by the linear system theory and an integral

  17. CERN Health Insurance Scheme (CHIS) Contributions – Changes for 2012

    CERN Multimedia

    HR Department

    2012-01-01

    Following the 2010 five-yearly review of financial and social conditions, which included the CERN Health Insurance Scheme (CHIS), the CERN Council decided in December 2010 to progressively increase the level of contributions over the period 2011-2015.   For 2012, the contribution rate of active and retired CHIS members will be 4.41%. The amounts of the fixed premiums for voluntarily insured members (e.g. users and associates) as well as the supplementary contributions for spouses with income from a professional activity increase accordingly : Voluntary contributions The full contribution based on Reference Salary II is now 1094 CHF per month. This fixed amount contribution is applied to voluntarily affiliated users and associates with normal coverage. Half of this amount (547 CHF) is applied to apprentices as well as to voluntarily affiliated users and associates with reduced coverage. Finally, an amount of 438 CHF is applied to children maintaining their insurance cover on a voluntary and tempo...

  18. Standardization of {sup 64}Cu using an improved decay scheme

    Energy Technology Data Exchange (ETDEWEB)

    Amiot, M.N., E-mail: marie-noelle.amiot@cea.fr [CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), CE Saclay, 91191 Gif-sur-Yvette Cedex (France); Be, M.M.; Branger, T.; Cassette, P.; Lepy, M.C.; Menesguen, Y. [CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), CE Saclay, 91191 Gif-sur-Yvette Cedex (France); Da Silva, I. [CNRS-CEMHTI, Site cyclotron, 45071 Orleans Cedex (France)

    2012-08-21

    A {sup 64}Cu solution was standardized by means of liquid scintillation counting. The activity of the solution was also determined with an ionization chamber whose response was simulated by using a Monte Carlo code. The photon emission intensities including K X-rays were determined to be I{sub 511}=35.1 (3)%; I{sub 1346}=0.472 (12)%, IK{alpha}=14.41 (15)%, IK{beta}=2.01 (3)%, respectively. {sup 64}Cu half-life was also determined as 12.718 (23) h. The new decay scheme used in the present work was established following the EURAMET 1085 exercise where a good agreement between activity measurement techniques was found.

  19. A parcellation scheme for human left lateral parietal cortex.

    Science.gov (United States)

    Nelson, Steven M; Cohen, Alexander L; Power, Jonathan D; Wig, Gagan S; Miezin, Francis M; Wheeler, Mark E; Velanova, Katerina; Donaldson, David I; Phillips, Jeffrey S; Schlaggar, Bradley L; Petersen, Steven E

    2010-07-15

    The parietal lobe has long been viewed as a collection of architectonic and functional subdivisions. Though much parietal research has focused on mechanisms of visuospatial attention and control-related processes, more recent functional neuroimaging studies of memory retrieval have reported greater activity in left lateral parietal cortex (LLPC) when items are correctly identified as previously studied ("old") versus unstudied ("new"). These studies have suggested functional divisions within LLPC that may provide distinct contributions toward recognition memory judgments. Here, we define regions within LLPC by developing a parcellation scheme that integrates data from resting-state functional connectivity MRI and functional MRI. This combined approach results in a 6-fold parcellation of LLPC based on the presence (or absence) of memory-retrieval-related activity, dissociations in the profile of task-evoked time courses, and membership in large-scale brain networks. This parcellation should serve as a roadmap for future investigations aimed at understanding LLPC function.

  20. Uncertainty of Microphysics Schemes in CRMs

    Science.gov (United States)

    Tao, W. K.; van den Heever, S. C.; Wu, D.; Saleeby, S. M.; Lang, S. E.

    2015-12-01

    Microphysics is the framework through which to understand the links between interactive aerosol, cloud and precipitation processes. These processes play a critical role in the water and energy cycle. CRMs with advanced microphysics schemes have been used to study the interaction between aerosol, cloud and precipitation processes at high resolution. But, there are still many uncertainties associated with these microphysics schemes. This has arisen, in part, from the fact microphysical processes cannot be measured directly; instead, cloud properties, which can be measured, are and have been used to validate model results. The utilization of current and future global high-resolution models is rapidly increasing and are at what has been traditional CRM resolutions and are using microphysics schemes that were developed in traditional CRMs. A potential NASA satellite mission called the Cloud and Precipitation Processes Mission (CaPPM) is currently being planned for submission to the NASA Earth Science Decadal Survey. This mission could provide the necessary global estimates of cloud and precipitation properties with which to evaluate and improve dynamical and microphysical parameterizations and the feedbacks. In order to facilitate the development of this mission, CRM simulations have been conducted to identify microphysical processes responsible for the greatest uncertainties in CRMs. In this talk, we will present results from numerical simulations conducted using two CRMs (NU-WRF and RAMS) with different dynamics, radiation, land surface and microphysics schemes. Specifically, we will conduct sensitivity tests to examine the uncertainty of the some of the key ice processes (i.e. riming, melting, freezing and shedding) in these two-microphysics schemes. The idea is to quantify how these two different models' respond (surface rainfall and its intensity, strength of cloud drafts, LWP/IWP, convective-stratiform-anvil area distribution) to changes of these key ice

  1. A novel and efficient user access control scheme for wireless body area sensor networks

    Directory of Open Access Journals (Sweden)

    Santanu Chatterjee

    2014-07-01

    Full Text Available Wireless body area networks (WBANs can be applied to provide healthcare and patient monitoring. However, patient privacy can be vulnerable in a WBAN unless security is considered. Access to authorized users for the correct information and resources for different services can be provided with the help of efficient user access control mechanisms. This paper proposes a new user access control scheme for a WBAN. The proposed scheme makes use of a group-based user access ID, an access privilege mask, and a password. An elliptic curve cryptography-based public key cryptosystem is used to ensure that a particular legitimate user can only access the information for which he/she is authorized. We show that our scheme performs better than previously existing user access control schemes. Through a security analysis, we show that our scheme is secure against possible known attacks. Furthermore, through a formal security verification using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool, we show that our scheme is also secure against passive and active attacks.

  2. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-06-08

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas's currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs.

  3. Gender and power contestations over water use in irrigation schemes: Lessons from the lake Chilwa basin

    Science.gov (United States)

    Nkhoma, Bryson; Kayira, Gift

    2016-04-01

    Over the past two decades, Malawi has been adversely hit by climatic variability and changes, and irrigation schemes which rely mostly on water from rivers have been negatively affected. In the face of dwindling quantities of water, distribution and sharing of water for irrigation has been a source of contestations and conflicts. Women who constitute a significant section of irrigation farmers in schemes have been major culprits. The study seeks to analyze gender contestations and conflicts over the use of water in the schemes developed in the Lake Chilwa basin, in southern Malawi. Using oral and written sources as well as drawing evidence from participatory and field observations conducted at Likangala and Domasi irrigation schemes, the largest schemes in the basin, the study observes that women are not passive victims of male domination over the use of dwindling waters for irrigation farming. They have often used existing political and traditional structures developed in the management of water in the schemes to competitively gain monopoly over water. They have sometimes expressed their agency by engaging in irrigation activities that fall beyond the control of formal rules and regulations of irrigation agriculture. Other than being losers, women are winning the battle for water and land resources in the basin.

  4. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-01-01

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas’s currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs. PMID:27338382

  5. A SINGLE STEP SCHEME WITH HIGH ACCURACY FOR PARABOLIC PROBLEM

    Institute of Scientific and Technical Information of China (English)

    陈传淼; 胡志刚

    2001-01-01

    A single step scheme with high accuracy for solving parabolic problem is proposed. It is shown that this scheme possesses good stability and fourth order accuracy with respect to both time and space variables, which are superconvergent.

  6. A NEW EFFICIENT ID-BASED PROXY BLIND SIGNATURE SCHEME

    Institute of Scientific and Technical Information of China (English)

    Ming Yang; Wang Yumin

    2008-01-01

    In a proxy blind signature scheme, the proxy signer is allowed to generate a blind signature on behalf of the original signer. The proxy blind signature scheme is useful in several applications such as e-voting, e-payment, etc. Recently, Zheng, et al. presented an IDentity (ID)-based proxy blind signature. In this paper, a new efficient ID-based proxy blind signature scheme from bilinear pairings is proposed, which can satisfy the security properties of both the proxy signatures and the blind signature schemes. Analysis of the scheme efficiency shows that the new scheme is more efficient than Zheng, et al.'s scheme. The proposed scheme is more practical in the real world.

  7. Threshold Signature Scheme Based on Discrete Logarithm and Quadratic Residue

    Institute of Scientific and Technical Information of China (English)

    FEI Ru-chun; WANG Li-na

    2004-01-01

    Digital signature scheme is a very important research field in computer security and modern cryptography.A(k,n) threshold digital signature scheme is proposed by integrating digital signature scheme with Shamir secret sharing scheme.It can realize group-oriented digital signature, and its security is based on the difficulty in computing discrete logarithm and quadratic residue on some special conditions.In this scheme, effective digital signature can not be generated by any k-1 or fewer legal users, or only by signature executive.In addition, this scheme can identify any legal user who presents incorrect partial digital signature to disrupt correct signature, or any illegal user who forges digital signature.A method of extending this scheme to an Abelian group such as elliptical curve group is also discussed.The extended scheme can provide rapider computing speed and stronger security in the case of using shorter key.

  8. A New Achievability Scheme for the Relay Channel

    CERN Document Server

    Kang, Wei

    2007-01-01

    In this paper, we propose a new coding scheme for the general relay channel. This coding scheme is in the form of a block Markov code. The transmitter uses a superposition Markov code. The relay compresses the received signal and maps the compressed version of the received signal into a codeword conditioned on the codeword of the previous block. The receiver performs joint decoding after it has received all of the B blocks. We show that this coding scheme can be viewed as a generalization of the well-known Compress-And-Forward (CAF) scheme proposed by Cover and El Gamal. Our coding scheme provides options for preserving the correlation between the channel inputs of the transmitter and the relay, which is not possible in the CAF scheme. Thus, our proposed scheme may potentially yield a larger achievable rate than the CAF scheme.

  9. Statistical Hiding Fuzzy Commitment Scheme for Securing Biometric Templates

    Directory of Open Access Journals (Sweden)

    Alawi A. Al-Saggaf

    2013-04-01

    Full Text Available By considering the security flaws in cryptographic hash functions, any commitment scheme designed straight through hash function usage in general terms is insecure. In this paper, we develop a general fuzzy commitment scheme called an ordinary fuzzy commitment scheme (OFCS, in which many fuzzy commitment schemes with variety complexity assumptions is constructed. The scheme is provably statistical hiding (the advisory gets almost no statistically advantages about the secret message. The efficiency of our scheme offers different security assurance, and the trusted third party is not involved in the exchange of commitment.The characteristic of our scheme makes it useful for biometrics systems. If the biometrics template is compromised, then there is no way to use it directly again even in secure biometrics systems. This paper combines biometrics and OFCS to achieve biometric protection scheme using smart cards with renewability of protected biometrics template property.

  10. An improved identity-based proxy ring signature scheme

    Institute of Scientific and Technical Information of China (English)

    Lang Weimin; Yang Zongkai; Cheng Wenqing; Tan Yunmeng

    2005-01-01

    Proxy ring signature schemes have been shown to be useful in various applications, such as electronic polling, electronic payment, etc. In this paper, we point out that Lang's scheme is unreasonable and propose an improved Identity-based proxy ring scheme from bilinear pairings which is reasonable and overcomes the deficiencies of Lang's scheme. Our scheme can prevent the original signer from generating the proxy ring signature, thus the profits of the proxy signer are guaranteed. In addition, our scheme satisfies all the security requirements of proxy ring signature, I.e. Signer-ambiguity, non-forgeability, verification, non-deniability and distinguishability. As compared with Zhang's scheme, our scheme is a computational efficiency improvement for signature verification because the computational cost of bilinear pairings required is reduced from O(n) to O(1).

  11. Quantum Communication Scheme Using Non-symmetric Quantum Channel

    Institute of Scientific and Technical Information of China (English)

    CAO Hai-Jing; CHEN Zhong-Hua; SONG He-Shan

    2008-01-01

    A theoretical quantum communication scheme based on entanglement swapping and superdense coding is proposed with a 3-dimensional Bell state and 2-dimensional Bell state function as quantum channel quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme. The scheme is secure and has high source capacity. At last, we generalize the quantum communication scheme to d-dimensional quantum channel.

  12. An Efficient Proactive RSA Scheme for Ad Hoc Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; CHEN Ke-fei

    2007-01-01

    A proactive threshold signature scheme is very important to tolerate mobile attack in mobile ad hoc networks. In this paper, we propose an efficient proactive threshold RSA signature scheme for ad hoc networks. The scheme consists of three protocols: the initial secret share distribution protocol, the signature generation protocol and the secret share refreshing protocol. Our scheme has three advantages. First, the signature generation protocol is efficient. Second, the signature generation protocol is resilient. Third, the share refreshing protocol is efficient.

  13. An Advanced Threshold Secret Sharing Scheme for Identifying Cheaters

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-cui; ZHANG Jian-zhong

    2003-01-01

    In this paper an advanced threshold secret sharing scheme for identifying cheaters is proposed by using authentication codes. The performance of the scheme is discussed. The results show that in the scheme the valid shareholders can not only identify the impersonation of an adversary, but also detect cheating of some valid shareholders. In particular one honest shareholder is able to detect cheating of other participants forming a collection, and the information rate of the scheme is higher than that of others.

  14. Cryptanalysis and Improvement of Signcryption Schemes on Elliptic Curves

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-xue; CHEN Ke-fei; LI Shi-qun

    2005-01-01

    In this paper, we analyze two signcryption schemes on elliptic curves proposed by Zheng Yu-liang and Hideki Imai. We point out a serious problem with the schemes that the elliptic curve based signcryption schemes lose confidentiality to gain non-repudiation. We also propose two improvement versions that not only overcome the security leak inherent in the schemes but also provide public verifiability or forward security. Our improvement versions require smaller computing cost than that required by signature-thenencryption methods.

  15. A Fuzzy Commitment Scheme with McEliece's Cipher

    Directory of Open Access Journals (Sweden)

    Deo Brat Ojha

    2010-04-01

    Full Text Available In this paper an attempt has been made to explain a fuzzy commitment scheme with McEliece scheme. The efficiency and security of this cryptosystem is comparatively better than any other cryptosystem. This scheme is one of the interesting candidates for post quantum cryptography. Hence our interest to deal with this system with fuzzy commitment scheme. The concept itself is illustrated with the help of a simple situation and the validation of mathematical experimental verification is provided.

  16. Direct scheme for measuring the geometric quantum discord

    CERN Document Server

    Jin, Jia-sen; Yu, Chang-shui; Song, He-shan

    2011-01-01

    We propose a scheme to directly measure the exact value of geometric quantum discord of an arbitrary two-qubit state. We only need to perform the projective measurement in the all anti-symmetric subspace and our scheme is parametrically efficient in contrast to the widely adopted quantum state tomography scheme in the sense of less parameter estimations and projectors. Moreover, the present scheme can be easily realized with the current experimental techniques.

  17. An Identity-Based Strong Designated Verifier Proxy Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    WANG Qin; CAO Zhenfu

    2006-01-01

    In a strong designated verifier proxy signature scheme, a proxy signer can generate proxy signature on behalf of an original signer, but only the designated verifier can verify the validity of the proxy signature. In this paper, we first define the security requirements for strong designated verifier proxy signature schemes. And then we construct an identity-based strong designated verifier proxy signature scheme. We argue that the proposed scheme satisfies all of the security requirements.

  18. Verifiable (t, n) Threshold Signature Scheme Based on Elliptic Curve

    Institute of Scientific and Technical Information of China (English)

    WANG Hua-qun; ZHAO Jun-xi; ZHANG Li-jun

    2005-01-01

    Based on the difficulty of solving the ECDLP (elliptic curve discrete logarithm problem) on the finite field,we present a (t, n) threshold signature scheme and a verifiable key agreement scheme without trusted party. Applying a modified elliptic curve signature equation, we get a more efficient signature scheme than the existing ECDSA (elliptic curve digital signature algorithm) from the computability and security view. Our scheme has a shorter key, faster computation, and better security.

  19. Scheme for Implementation of Quantum Game in Cavity QED

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Chun; CAO Shu-Ai; WU Yue-Qin; FANG Mao-Fa; LI Huai-Fan; ZHENG Xiao-Juan; ZHAO Ren; WANG Xin-Wen; LI Ze-Hua

    2008-01-01

    We propose an experimentally feasible scheme to implement two-player quantum game in cavity quantum electrodynamics (QED). During the process, the cavity is only virtually excited, thus our scheme is insensitive to the cavity field states and cavity decay. The scheme can be realized in the range of current cavity QED techniques.

  20. An Annotation Scheme for Social Interaction in Digital Playgrounds

    NARCIS (Netherlands)

    Moreno, Alejandro M.; Delden, van Robby; Reidsma, Dennis; Poppe, Ronald; Heylen, Dirk; Herrlich, Marc; Malaka, Rainer; Masuch, Maic

    2012-01-01

    This paper introduces a new annotation scheme, designed specifically to study children's social interactions during play in digital playgrounds. The scheme is motivated by analyzing relevant literature, combined with observations from recordings of play sessions. The scheme allows us to analyze how

  1. The hybrid Eulerian Lagrangian numerical scheme tested with Chemistry

    Directory of Open Access Journals (Sweden)

    A. B. Hansen

    2012-11-01

    Full Text Available A newly developed advection scheme, the Hybrid Eulerian Lagrangian (HEL scheme, has been tested, including a module for atmospheric chemistry, including 58 chemical species, and compared to two other traditional advection schemes; a classical pseudospectral Eulerian method the Accurate Space Derivative (ASD scheme and the bi-cubic semi-Lagrangian (SL scheme using classical rotation tests. The rotation tests have been designed to test and compare the advection schemes for different spatial and temporal resolutions in different chemical conditions (rural and urban and for different shapes (cone and slotted cylinder giving the advection schemes different challenges with respect to relatively slow or fast chemistry and smooth or sharp gradients, respectively. In every test, error measures have been calculated and used for ranking of the advection schemes with respect to performance, i.e. lowest overall errors for all chemical species. Furthermore, the HEL and SL schemes have been compared in a shallow water model, demonstrating the performance in a more realistic non-linear deformation flow.

    The results in this paper show that the new advection scheme, HEL, by far outperforms both the Eulerian and semi-Lagrangian schemes with very low error estimates compared to the two other schemes. Although no analytic solution can be obtained for the performance in the non-linear shallow water model flow, the tracer distribution appears realistic as compared to LMCSL when a mixing between local parcel concentrations is introduced in HEL.

  2. A quantum identification scheme based on polarization modulation

    Institute of Scientific and Technical Information of China (English)

    He Guang-Qiang; Zeng Gui-Hua

    2005-01-01

    Aquantum idetification scheme including registration and identification phases is proposed.The user' passwords are transmitted by qubit string and recorded as set of quantum operators.The security of the proposed scheme is guarateed by the no-coloning theorem.Based on photon polarization modulation,an experimental approach is also designed to implement our proposed scheme.

  3. General Scheme for the Construction of a Protected Qubit Subspace

    DEFF Research Database (Denmark)

    Aharon, N.; Drewsen, M.; Retzker, A.

    2013-01-01

    We present a new robust decoupling scheme suitable for half integer angular momentum states. The scheme is based on continuous dynamical decoupling techniques by which we create a protected qubit subspace. Our scheme predicts a coherence time of ~1 second, as compared to typically a few...

  4. Conditional linear-optical measurement schemes generate effective photon nonlinearities

    CERN Document Server

    Lapaire, G G; Dowling, J P; Sipe, J E; Dowling, Jonathan P.

    2003-01-01

    We provide a general approach for the analysis of optical state evolution under conditional measurement schemes, and identify the necessary and sufficient conditions for such schemes to simulate unitary evolution on the freely propagating modes. If such unitary evolution holds, an effective photon nonlinearity can be identified. Our analysis extends to conditional measurement schemes more general than those based solely on linear optics.

  5. A Formal Model for the Security of Proxy Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    GU Chun-xiang; ZHU Yue-fei; ZHANG Ya-juan

    2005-01-01

    This paper provides theoretical foundations for the secure proxy signature primitive. We present a formal model for the security of proxy signature schemes, which defines the capabilities of the adversary and the security goals to capture which mean for a proxy signature scheme to be secure. Then, we present an example of proxy signature scheme that can be proven secure in the standard model.

  6. Vehicle scheduling schemes for commercial and emergency logistics integration.

    Directory of Open Access Journals (Sweden)

    Xiaohui Li

    Full Text Available In modern logistics operations, large-scale logistics companies, besides active participation in profit-seeking commercial business, also play an essential role during an emergency relief process by dispatching urgently-required materials to disaster-affected areas. Therefore, an issue has been widely addressed by logistics practitioners and caught researchers' more attention as to how the logistics companies achieve maximum commercial profit on condition that emergency tasks are effectively and performed satisfactorily. In this paper, two vehicle scheduling models are proposed to solve the problem. One is a prediction-related scheme, which predicts the amounts of disaster-relief materials and commercial business and then accepts the business that will generate maximum profits; the other is a priority-directed scheme, which, firstly groups commercial and emergency business according to priority grades and then schedules both types of business jointly and simultaneously by arriving at the maximum priority in total. Moreover, computer-based simulations are carried out to evaluate the performance of these two models by comparing them with two traditional disaster-relief tactics in China. The results testify the feasibility and effectiveness of the proposed models.

  7. Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

    Directory of Open Access Journals (Sweden)

    Byung Eun Lee

    2014-07-01

    Full Text Available This paper describes a current differential relay for transformer protection that operates in conjunction with a core saturation detection-based blocking algorithm. The differential current for the magnetic inrush or over-excitation has a point of inflection at the start and end of each saturation period of the transformer core. At these instants, discontinuities arise in the first-difference function of the differential current. The second- and third-difference functions convert the points of inflection into pulses, the magnitudes of which are large enough to detect core saturation. The blocking signal is activated if the third-difference of the differential current is larger than the threshold and is maintained for one cycle. In addition, a method to discriminate between transformer saturation and current transformer (CT saturation is included. The performance of the proposed blocking scheme was compared with that of a conventional harmonic blocking method. The test results indicate that the proposed scheme successfully discriminates internal faults even with CT saturation from the magnetic inrush, over-excitation, and external faults with CT saturation, and can significantly reduce the operating time delay of the relay.

  8. Vehicle scheduling schemes for commercial and emergency logistics integration.

    Science.gov (United States)

    Li, Xiaohui; Tan, Qingmei

    2013-01-01

    In modern logistics operations, large-scale logistics companies, besides active participation in profit-seeking commercial business, also play an essential role during an emergency relief process by dispatching urgently-required materials to disaster-affected areas. Therefore, an issue has been widely addressed by logistics practitioners and caught researchers' more attention as to how the logistics companies achieve maximum commercial profit on condition that emergency tasks are effectively and performed satisfactorily. In this paper, two vehicle scheduling models are proposed to solve the problem. One is a prediction-related scheme, which predicts the amounts of disaster-relief materials and commercial business and then accepts the business that will generate maximum profits; the other is a priority-directed scheme, which, firstly groups commercial and emergency business according to priority grades and then schedules both types of business jointly and simultaneously by arriving at the maximum priority in total. Moreover, computer-based simulations are carried out to evaluate the performance of these two models by comparing them with two traditional disaster-relief tactics in China. The results testify the feasibility and effectiveness of the proposed models.

  9. Novel Fault Diagnosis Scheme for HVDC System via ESO

    Institute of Scientific and Technical Information of China (English)

    YAN Bing-yong; TIAN Zuo-hua; SHI Song-jiao

    2007-01-01

    A novel fault detection and identification (FDI) scheme for HVDC (High Voltage Direct Current Transmission) system was presented. It was based on the unique active disturbance rejection concept, where the HVDC system faults were estimated using an extended states observer (ESO). Firstly, the mathematical model of HVDC system was constructed, where the system states and disturbance were treated as an extended state. An augment HVDC system was established by using the extended state in rectify side and converter side, respectively. Then, a fault diagnosis filter was established to diagnose the HVDC system faults via the ESO theory. The evolution of the extended state in the augment HVDC system can reflect the actual system faults and disturbances, which can be used for the fault diagnosis purpose. A novel feature of this approach is that it can simultaneously detect and identify the shape and magnitude of the HVDC faults and disturbance. Finally, different kinds of HVDC faults were simulated to illustrate the feasibility and effectiveness of the proposed ESO based FDI approach. Compared with the neural network based or support vector machine based FDI approach, the ESO based FDI scheme can reduce the fault detection time dramatically and track the actual system fault accurately. What's more important, it needs not do complex online calculations and the training of neural network so that it can be applied into practice.

  10. Motion feature extraction scheme for content-based video retrieval

    Science.gov (United States)

    Wu, Chuan; He, Yuwen; Zhao, Li; Zhong, Yuzhuo

    2001-12-01

    This paper proposes the extraction scheme of global motion and object trajectory in a video shot for content-based video retrieval. Motion is the key feature representing temporal information of videos. And it is more objective and consistent compared to other features such as color, texture, etc. Efficient motion feature extraction is an important step for content-based video retrieval. Some approaches have been taken to extract camera motion and motion activity in video sequences. When dealing with the problem of object tracking, algorithms are always proposed on the basis of known object region in the frames. In this paper, a whole picture of the motion information in the video shot has been achieved through analyzing motion of background and foreground respectively and automatically. 6-parameter affine model is utilized as the motion model of background motion, and a fast and robust global motion estimation algorithm is developed to estimate the parameters of the motion model. The object region is obtained by means of global motion compensation between two consecutive frames. Then the center of object region is calculated and tracked to get the object motion trajectory in the video sequence. Global motion and object trajectory are described with MPEG-7 parametric motion and motion trajectory descriptors and valid similar measures are defined for the two descriptors. Experimental results indicate that our proposed scheme is reliable and efficient.

  11. Feature extraction for an image retrieving scheme

    OpenAIRE

    Fuertes García, José Manuel; Lucena López, Manuel José; Pérez de la Blanca Capilla, Nicolás; Fernández Valdivia, Joaquín

    1999-01-01

    In this paper we present two basic modules whithin the designed scheme for retrieving images of a database from the object colour and shape in the scenes. On the one hand, we desing a new method to detect edges in colour images. We offer a new approach to the perceptual space (H,S,I) (an Uniform Chromatic Scale space) About wich we describe its properties as well as the metric to work in it. On the other hand, we develop an information simplifying process to form a graphic structure en wich t...

  12. A Classification Scheme for Glaciological AVA Responses

    Science.gov (United States)

    Booth, A.; Emir, E.

    2014-12-01

    A classification scheme is proposed for amplitude vs. angle (AVA) responses as an aid to the interpretation of seismic reflectivity in glaciological research campaigns. AVA responses are a powerful tool in characterising the material properties of glacier ice and its substrate. However, before interpreting AVA data, careful true amplitude processing is required to constrain basal reflectivity and compensate amplitude decay mechanisms, including anelastic attenuation and spherical divergence. These fundamental processing steps can be difficult to design in cases of noisy data, e.g. where a target reflection is contaminated by surface wave energy (in the case of shallow glaciers) or by energy reflected from out of the survey plane. AVA methods have equally powerful usage in estimating the fluid fill of potential hydrocarbon reservoirs. However, such applications seldom use true amplitude data and instead consider qualitative AVA responses using a well-defined classification scheme. Such schemes are often defined in terms of the characteristics of best-fit responses to the observed reflectivity, e.g. the intercept (I) and gradient (G) of a linear approximation to the AVA data. The position of the response on a cross-plot of I and G then offers a diagnostic attribute for certain fluid types. We investigate the advantages in glaciology of emulating this practice, and develop a cross-plot based on the 3-term Shuey AVA approximation (using I, G, and a curvature term C). Model AVA curves define a clear lithification trend: AVA responses to stiff (lithified) substrates fall discretely into one quadrant of the cross-plot, with positive I and negative G, whereas those to fluid-rich substrates plot diagonally opposite (in the negative I and positive G quadrant). The remaining quadrants are unoccupied by plausible single-layer responses and may therefore be diagnostic of complex thin-layer reflectivity, and the magnitude and polarity of the C term serves as a further indicator

  13. Efficient Scheme for Optimizing Quantum Fourier Circuits

    Institute of Scientific and Technical Information of China (English)

    JIANG Min; ZHANG Zengke; Tzyh-Jong Tarn

    2008-01-01

    In quantum circuits, importing of additional qubits can reduce the operation time and prevent de-coherence induced by the environment. However, excessive qubits may make the quantum system vulner-able. This paper describes how to relax existing qubits without additional qubits to significantly reduce the operation time of the quantum Fourier circuit compared to a circuit without optimization. The results indicate that this scheme makes full use of the qubits relaxation. The concepts can be applied to improve similar quantum circuits and guide the physical implementations of quantum algorithms or devices.

  14. New Financing Schemes of Public Infrastructure

    Directory of Open Access Journals (Sweden)

    Ignacio de la Riva

    2017-01-01

    Full Text Available Public works procurements and concessions are traditional legal techniques used to shape the financing of public infrastructure. Fiscal constraints faced by public administrations at the end of the 20th century, and the subsequent increase of private participation in the provision of public goods and services, encouraged the development of new legal schemes allowing a higher degree of private investment in public infrastructure; such as Public Private Partnerships, project finance, securitizations, the shadow toll, turn-key agreements, public leasing and public trusts.

  15. An algebraic approach to association schemes

    CERN Document Server

    Zieschang, Paul-Hermann

    1996-01-01

    The primary object of the lecture notes is to develop a treatment of association schemes analogous to that which has been so successful in the theory of finite groups. The main chapters are decomposition theory, representation theory, and the theory of generators. Tits buildings come into play when the theory of generators is developed. Here, the buildings play the role which, in group theory, is played by the Coxeter groups. - The text is intended for students as well as for researchers in algebra, in particular in algebraic combinatorics.

  16. Rural poverty reduction through centrally sponsored schemes.

    Science.gov (United States)

    Saxena, N C

    2007-10-01

    This paper discusses the evolving profile of poverty in India and reviews the national performance of selected anti-poverty programmes between 1997-1998 and 2005. For each programme, it outlines the budgetary allocation principle used for the States and districts and analyzes budgetary performance over the period. The main objective is to explore the extent to which the anti-poverty programmes are reaching their target groups effectively. Finally, it identifies the specific factors responsible for under-performance and provides a set of recommendations for policy makers and programme implementers which could help improve the outcomes of the schemes.

  17. Advanced Coarsening Schemes for Graph Partitioning

    CERN Document Server

    Safro, Ilya; Schulz, Christian

    2012-01-01

    The graph partitioning problem is widely used and studied in many practical and theoretical applications. The multilevel strategies represent today one of the most effective and efficient generic frameworks for solving this problem on large-scale graphs. Most of the attention in designing the multilevel partitioning frameworks has been on the refinement phase. In this work we focus on the coarsening phase, which is responsible for creating structurally similar to the original but smaller graphs. We compare different matching- and AMG-based coarsening schemes, experiment with the algebraic distance between nodes, and demonstrate computational results on several classes of graphs that emphasize the running time and quality advantages of different coarsenings.

  18. Constraint-Preserving Scheme for Maxwell's Equations

    CERN Document Server

    Tsuchiya, Takuya

    2016-01-01

    We derive the discretized Maxwell's equations using the discrete variational derivative method (DVDM), calculate the evolution equation of the constraint, and confirm that the equation is satisfied at the discrete level. Numerical simulations showed that the results obtained by the DVDM are superior to those obtained by the Crank-Nicolson scheme. In addition, we study the two types of the discretized Maxwell's equations by the DVDM and conclude that if the evolution equation of the constraint is not conserved at the discrete level, then the numerical results are also unstable.

  19. DIFFERENCE SCHEMES BASING ON COEFFICIENT APPROXIMATION

    Institute of Scientific and Technical Information of China (English)

    MOU Zong-ze; LONG Yong-xing; QU Wen-xiao

    2005-01-01

    In respect of variable coefficient differential equations, the equations of coefficient function approximation were more accurate than the coefficient to be frozen as a constant in every discrete subinterval. Usually, the difference schemes constructed based on Taylor expansion approximation of the solution do not suit the solution with sharp function.Introducing into local bases to be combined with coefficient function approximation, the difference can well depict more complex physical phenomena, for example, boundary layer as well as high oscillatory, with sharp behavior. The numerical test shows the method is more effective than the traditional one.

  20. Cryptanalysis of Two Fault Countermeasure Schemes

    DEFF Research Database (Denmark)

    Banik, Subhadeep; Bogdanov, Andrey

    2015-01-01

    is meant for the protection of block ciphers like AES. The second countermeasure was proposed in IEEE-HOST 2015 and protects the Grain-128 stream cipher. The design divides the output function used in Grain-128 into two components. The first called the masking function, masks the input bits to the output......In this paper, we look at two fault countermeasure schemes proposed very recently in literature. The first proposed in ACISP 2015 constructs a transformation function using a cellular automata based linear diffusion, and a non-linear layer using a series of bent functions. This countermeasure...

  1. Research on Lorry Road User Charging Scheme

    Directory of Open Access Journals (Sweden)

    Chao Sui

    2012-01-01

    Full Text Available In the 2011-2015 Business Plan, a lorry road user charging scheme has been planned to implement by the Coalition Government by 2014. This study will describe the possible impacts of such a system on the road haulage sector and the ways in which logistics providers might utilize different operating practices and technology to improve their operational performance under such circumstances in the UK. And this essay will cover the possible uses for Intelligent Transport Systems and new working practices using specific case study examples. Finally, the impacts of LRUC and several feasible countermeasures will be discussed in the following text.

  2. ATLAS PhD Grant Scheme

    CERN Multimedia

    2016-01-01

    In this #CERNandSociety video, the 3 PhD students, awarded the ATLAS PhD Grant in 2015, talk about their research work within the ATLAS Collaboration and how this experience has shaped their future. Find out more about the ATLAS PhD Grant Scheme: cern.ch/ATLASPhDGrant This programme is just one of the many #CERNandSociety projects at CERN. Find out more and how you can be involved: http://cern.ch/go/pBt7

  3. Secure Biometric E-Voting Scheme

    Science.gov (United States)

    Ahmed, Taha Kh.; Aborizka, Mohamed

    The implementation of the e-voting becomes more substantial with the rapid increase of e-government development. The recent growth in communications and cryptographic techniques facilitate the implementation of e-voting. Many countries introduced e-voting systems; unfortunately most of these systems are not fully functional. In this paper we will present an e-voting scheme that covers most of the e-voting requirements, smart card and biometric recognition technology were implemented to guarantee voter's privacy and authentication.

  4. Cosmological SUSY Breaking and the Pyramid Schemes

    CERN Document Server

    Banks, T

    2014-01-01

    I review the ideas of holographic space-time (HST), Cosmological SUSY breaking (CSB), and the Pyramid Schemes, which are the only known models of Tera-scale physics consistent with CSB, current particle data, and gauge coupling unification. There is considerable uncertainty in the estimate of the masses of supersymmetric partners of the standard model particles, but the model predicts that the gluino is probably out of reach of the LHC, squarks may be in reach, and the NLSP is a right handed slepton, which should be discovered soon.

  5. Labelling schemes: From a consumer perspective

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2000-01-01

    . A recent MAPP study has investigated the value consumers attach the Government-controlled labels 'Ø-mærket' and 'Den Blå Lup' and the private supermarket label 'Mesterhakket' when they purchase minced meat. The results reveal four consumer segments that use labelling schemes for food products very....... The remaining consumers, about 55%, trust the institutions guaranteeing the labels and they use the labels as a signal without actually knowing the content of each label. Segment composition will probably change depending on the food group studied. It is therefore recommended that the different consumer types...

  6. Benefit Reentitlement Conditions in Unemployment Insurance Schemes

    DEFF Research Database (Denmark)

    Andersen, Torben M.; Christoffersen, Mark Strøm; Svarer, Michael

    Unemployment insurance schemes include conditions on past employment history as part of the eligibility conditions. This aspect is often neglected in the literature which primarily focuses on benefit levels and benefit duration. In a search-matching framework we show that benefit duration...... and employment requirements are substitute instruments in affecting job search incentives and thus gross unemployment. We analyse the optimal design of the unemployment insurance system (benefit levels, duration and employment requirements) under a utilitarian social welfare function. Simulations show...... that a higher insurance motive captured by more risk aversion implies higher benefit generosity and more lax employment requirements but also shortened benefit duration....

  7. Autonomous Droop Scheme With Reduced Generation Cost

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Loh, Poh Chiang; Wang, Peng

    2014-01-01

    Droop schemes have traditionally been applied to the control of parallel synchronous generators in power systems. It has subsequently been brought over to the control of distributed generators (DGs) in microgrids with the same retained objective of proportional power sharing based on ratings....... This objective might, however, not suit microgrids well since DGs are usually of different types, unlike synchronous generators. Other factors like cost, efficiency, and emission penalty of each DG at different loading must be considered since they contribute directly to the total generation cost (TGC...... likely to be accepted by the industry. The reduction in TGC has been verified by experiment....

  8. Pay-what-you-want pricing schemes

    DEFF Research Database (Denmark)

    Kahsay, Goytom Abraha; Samahita, Margaret

    2015-01-01

    Pay-What-You-Want (PWYW) pricing schemes are becoming increasingly popular. We develop a model incorporating self-image into the buyer’s utility function and introduce heterogeneity in consumption utility and image-sensitivity, generating different purchase decisions and optimal prices across...... individuals. When a good’s fixed price is lower than a threshold fair value, PWYW can lead to a lower utility. This may result in a lower purchase rate and higher average price, accounting for previously unexplained field experimental evidence. An increase in the threshold value decreases the buyer’s utility...

  9. A simple data compression scheme for binary images of bacteria compared with commonly used image data compression schemes

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    A run length code compression scheme of extreme simplicity, used for image storage in an automated bacterial morphometry system, is compared with more common compression schemes, such as are used in the tag image file format. These schemes are Lempel-Ziv and Welch (LZW), Macintosh Packbits, and CCIT

  10. Optimal Numerical Schemes for Time Accurate Compressible Large Eddy Simulations: Comparison of Artificial Dissipation and Filtering Schemes

    Science.gov (United States)

    2014-11-01

    for Time Accurate Compressible Large Eddy Simulations : Comparison of Artificial Dissipation and Filtering Schemes 5b. GRANT NUMBER 5c. PROGRAM...Optimal Numerical Schemes for Time Accurate Compressible Large Eddy Simulations : Comparison of Artificial Dissipation and Filtering Schemes 67th

  11. Design of Infusion Schemes for Neuroreceptor Imaging

    DEFF Research Database (Denmark)

    Feng, Ling; Svarer, Claus; Madsen, Karine;

    2016-01-01

    for bolus infusion (BI) or programmed infusion (PI) experiments. Steady-state quantitative measurements can be made with one short scan and venous blood samples. The GABAA receptor ligand [(11)C]Flumazenil (FMZ) was chosen for this purpose, as it lacks a suitable reference region. Methods. Five bolus [(11)C......]FMZ-PET scans were conducted, based on which population-based PI and BI schemes were designed and tested in five additional healthy subjects. The design of a PI was assisted by an offline feedback controller. Results. The system could reproduce the measurements in blood and brain. With PI, [(11)C]FMZ steady...... state was attained within 40 min, which was 8 min earlier than the optimal BI (B/I ratio = 55 min). Conclusions. The system can design both BI and PI schemes to attain steady state rapidly. For example, subjects can be [(11)C]FMZ-PET scanned after 40 min of tracer infusion for 40 min with venous...

  12. A subgrid parameterization scheme for precipitation

    Directory of Open Access Journals (Sweden)

    S. Turner

    2011-07-01

    Full Text Available With increasing computing power, the horizontal resolution of numerical weather prediction (NWP models is improving and today reaches 1 to 5 km. Nevertheless, clouds and precipitation are still subgrid scale processes for most cloud types, such as cumulus and stratocumulus. Subgrid scale parameterizations for water vapor condensation have been in use for many years and are based on a prescribed PDF of relative humidity spatial variability within the grid, thus providing a diagnosis of the cloud fraction. A similar scheme is developed and tested here. It is based on a prescribed PDF of cloud water variability and a threshold value of liquid water content for droplet collection to derive a rain fraction within the model grid. Precipitation of rainwater raises additional concerns relative to the overlap of cloud and rain fractions, however. The scheme is developed following an analysis of data collected during field campaigns in stratocumulus (DYCOMS-II and fair weather cumulus (RICO and tested in a 1-D framework against large eddy simulations of these observed cases. The new parameterization is then implemented in a 3-D NWP model with a horizontal resolution of 2.5 km to simulate real cases of precipitating cloud systems over France.

  13. Deterministic Polynomial Factoring and Association Schemes

    CERN Document Server

    Arora, Manuel; Karpinski, Marek; Saxena, Nitin

    2012-01-01

    The problem of finding a nontrivial factor of a polynomial f(x) over a finite field F_q has many known efficient, but randomized, algorithms. The deterministic complexity of this problem is a famous open question even assuming the generalized Riemann hypothesis (GRH). In this work we improve the state of the art by focusing on prime degree polynomials; let n be the degree. If (n-1) has a `large' r-smooth divisor s, then we find a nontrivial factor of f(x) in deterministic poly(n^r,log q) time; assuming GRH and that s > sqrt{n/(2^r)}. Thus, for r = O(1) our algorithm is polynomial time. Further, for r > loglog n there are infinitely many prime degrees n for which our algorithm is applicable and better than the best known; assuming GRH. Our methods build on the algebraic-combinatorial framework of m-schemes initiated by Ivanyos, Karpinski and Saxena (ISSAC 2009). We show that the m-scheme on n points, implicitly appearing in our factoring algorithm, has an exceptional structure; leading us to the improved time ...

  14. Privacy protection schemes for fingerprint recognition systems

    Science.gov (United States)

    Marasco, Emanuela; Cukic, Bojan

    2015-05-01

    The deployment of fingerprint recognition systems has always raised concerns related to personal privacy. A fingerprint is permanently associated with an individual and, generally, it cannot be reset if compromised in one application. Given that fingerprints are not a secret, potential misuses besides personal recognition represent privacy threats and may lead to public distrust. Privacy mechanisms control access to personal information and limit the likelihood of intrusions. In this paper, image- and feature-level schemes for privacy protection in fingerprint recognition systems are reviewed. Storing only key features of a biometric signature can reduce the likelihood of biometric data being used for unintended purposes. In biometric cryptosystems and biometric-based key release, the biometric component verifies the identity of the user, while the cryptographic key protects the communication channel. Transformation-based approaches only a transformed version of the original biometric signature is stored. Different applications can use different transforms. Matching is performed in the transformed domain which enable the preservation of low error rates. Since such templates do not reveal information about individuals, they are referred to as cancelable templates. A compromised template can be re-issued using a different transform. At image-level, de-identification schemes can remove identifiers disclosed for objectives unrelated to the original purpose, while permitting other authorized uses of personal information. Fingerprint images can be de-identified by, for example, mixing fingerprints or removing gender signature. In both cases, degradation of matching performance is minimized.

  15. Password Authentication Based on Fractal Coding Scheme

    Directory of Open Access Journals (Sweden)

    Nadia M. G. Al-Saidi

    2012-01-01

    Full Text Available Password authentication is a mechanism used to authenticate user identity over insecure communication channel. In this paper, a new method to improve the security of password authentication is proposed. It is based on the compression capability of the fractal image coding to provide an authorized user a secure access to registration and login process. In the proposed scheme, a hashed password string is generated and encrypted to be captured together with the user identity using text to image mechanisms. The advantage of fractal image coding is to be used to securely send the compressed image data through a nonsecured communication channel to the server. The verification of client information with the database system is achieved in the server to authenticate the legal user. The encrypted hashed password in the decoded fractal image is recognized using optical character recognition. The authentication process is performed after a successful verification of the client identity by comparing the decrypted hashed password with those which was stored in the database system. The system is analyzed and discussed from the attacker’s viewpoint. A security comparison is performed to show that the proposed scheme provides an essential security requirement, while their efficiency makes it easier to be applied alone or in hybrid with other security methods. Computer simulation and statistical analysis are presented.

  16. IMPLEMENTATION OF THE NEW CAREER STRUCTURE SCHEME

    CERN Multimedia

    Human Resources Division

    2001-01-01

    CERN's new Merit Advancement and Promotion Scheme, MAPS, comes into force on 1 September, and all members of staff will soon be receiving the official letter of notification of their assimilation into the new scheme. In this announcement, we take a look at where you can learn about the new system. There will also be an article in the Weekly Bulletin at the end of the month, which will summarise the main changes. During the early summer, HR Division presented the new structure to the staff in the Laboratory via Divisional Information Meetings. The transparencies used in these meetings, along with a list of the most relevant questions and answers, a Career Path Guide as well as a general overview document are available on the HR Division web site http://cern.ch/CERN/Divisions/PE/. Hard copies of the latter document are also available from the Divisional secretariats. The first question most staff members will ask is how they will fit into the new career path structure. Via the same web page, they can type in th...

  17. Pricing Schemes in Cloud Computing: An Overview

    Directory of Open Access Journals (Sweden)

    Artan Mazrekaj

    2016-02-01

    Full Text Available Cloud Computing is one of the technologies with rapid development in recent years where there is increasing interest in industry and academia. This technology enables many services and resources for end users. With the rise of cloud services number of companies that offer various services in cloud infrastructure is increased, thus creating a competition on prices in the global market. Cloud Computing providers offer more services to their clients ranging from infrastructure as a service (IaaS, platform as a service (PaaS, software as a service (SaaS, storage as a service (STaaS, security as a service (SECaaS, test environment as a service (TEaaS. The purpose of providers is to maximize revenue by their price schemes, while the main goal of customers is to have quality of services (QoS for a reasonable price. The purpose of this paper is to compare and discuss several models and pricing schemes from different Cloud Computing providers.

  18. Finite-difference schemes for anisotropic diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Es, Bram van, E-mail: es@cwi.nl [Centrum Wiskunde and Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM (Netherlands)

    2014-09-01

    In fusion plasmas diffusion tensors are extremely anisotropic due to the high temperature and large magnetic field strength. This causes diffusion, heat conduction, and viscous momentum loss, to effectively be aligned with the magnetic field lines. This alignment leads to different values for the respective diffusive coefficients in the magnetic field direction and in the perpendicular direction, to the extent that heat diffusion coefficients can be up to 10{sup 12} times larger in the parallel direction than in the perpendicular direction. This anisotropy puts stringent requirements on the numerical methods used to approximate the MHD-equations since any misalignment of the grid may cause the perpendicular diffusion to be polluted by the numerical error in approximating the parallel diffusion. Currently the common approach is to apply magnetic field-aligned coordinates, an approach that automatically takes care of the directionality of the diffusive coefficients. This approach runs into problems at x-points and at points where there is magnetic re-connection, since this causes local non-alignment. It is therefore useful to consider numerical schemes that are tolerant to the misalignment of the grid with the magnetic field lines, both to improve existing methods and to help open the possibility of applying regular non-aligned grids. To investigate this, in this paper several discretization schemes are developed and applied to the anisotropic heat diffusion equation on a non-aligned grid.

  19. Information field dynamics for simulation scheme construction

    CERN Document Server

    Enßlin, Torsten A

    2012-01-01

    Information field dynamics (IFD) is introduced here as a framework to derive numerical schemes for the simulation of physical and other fields. Any simulation scheme updates a discretized field representation, the data in a computer's memory, for the next time step according to a discretized, approximate representation of the underlying field dynamics. Assumptions about the continuum field behavior on sub-grid scales are reflected in these rules, e.g. the field might be assumed to be constant within a grid cell, or to be some weighted average of neighboring data points, and the like. In contrast to such parametrized sub-grid field structures, IFD constructs non-parametric sub-grid field configurations from the combination of the data, representing constraints on possible field configurations, and prior assumptions on the sub-grid field statistics. Each of these field configurations can formally be evolved to a later moment since any differential operator of the dynamics can act on fields living in continuous ...

  20. Special Protection Scheme at BTPS Power Station

    Science.gov (United States)

    Ballal, Makarand Sudhakar; Suryawanshi, Hiralal Murlidhar; Ballal, Deepali Makarand; Mishra, Mahesh Kumar

    2016-03-01

    After 2003 free licensees' act in power sector, it is observed that many power plants from public sector as well as from private sectors are going to be commissioned. The load growth in India is about more than 10% pa. As these plants are going to connect to the power grid, therefore the grid is going to become more complicated. Also the problems related to grid stability are enhanced. There shall be possibilities regarding failure of grid system and under such circumstance it is always desirable to island minimum single generating unit in power plant of specified geographical area. After islanding the generating unit, this unit has to survive not only for the restoration of grid but also for power supply to important consumers. For the grid stability and effective survival of islanded generating unit, it is mandatory to maintain the power balance equation. This paper focuses on the lacunae's observed in implementation of special protection scheme to carry out islanding operation at Bhusawal Thermal Power Station (BTPS) by considering the case studies. The concepts of islanding, load shedding, generator tripping and along with importance of power balance equation is discussed. Efforts are made to provide the solution for the survival of islanding scheme.

  1. Novel copyright protection scheme for digital content

    Institute of Scientific and Technical Information of China (English)

    Fan Kefeng; Wang Meihua; Mo Wei; Zhao Xinhua

    2006-01-01

    A novel copyright protection scheme for digital content is presented, which is a private watermarking scheme based on the watermark embedding in the DCT domain and watermark extraction using independent component analysis (ICA). The system includes the key for watermark extraction and the host image. The algorithm splits the original image into blocks and classifies these blocks based on visual masking, that is, noise visibility function (NVF). Watermark components with different strength are inserted into chosen direct current components of DCT coefficients according to the classifier. The watermark extraction is based on the characteristic of the statistic independence of the host image, watermark and key. Principle component analysis (PCA) whitening process and FastICA techniques are introduced to ensure a blind watermark extraction without requiring the original image. Experimental results show the proposed technique is robust under attacks such as image filtering and adding noise, cropping and resizing. In addition, the proposed private watermarking system can be improved to the application of the DTV content protection system.

  2. European energy labelling scheme for windows

    Energy Technology Data Exchange (ETDEWEB)

    Belling Skou, Mette (VELUX A/S (Denmark)); Kragh, Jesper (DTU Byg, Denmarks Tekniske Univ., Lyngby (Denmark))

    2009-07-01

    In their proposals for revision of the energy labelling directive the European Commission has suggested to include windows. The paper introduces a proposal for an European energy labelling scheme of windows for replacement of windows in the existing building stock taking into consideration the energy performance of windows in both the heating and cooling seasons. The labelling scheme evaluates a methodology where the energy performance in the heating period is established with focus on heat loss and utilization of passive solar energy, whereas the energy performance in the summer (cooling) season will focus on reduction of solar radiation into the building. The methodology is developed with focus on CEN and ISO standardization. With inspiration from the American Energy Star programme for windows, Europe is divided into climate zones where the methodology for each zone is developed on basis of a reference building and climate data. A proposal for labelling will be presented for both heating and cooling seasons in order to enable the user to choose the right product for a specific performance. Based on data from the building stock in the individual climate zones, an energy saving potential for replacement of old windows with new low energy windows will be presented. The possibility for using energy labelling of windows as reference and requirement in the building legislation as an alternative to U-values, will be presented with among others examples from legislation in UK and Denmark.

  3. A new threshold signature scheme based on fuzzy biometric identity

    Institute of Scientific and Technical Information of China (English)

    Yongquan Cai; Ke Zhang

    2009-01-01

    The focus of this paper is to present the first threshold signature scheme based on biometric identity, which is acquired from a recently proposed fuzzy identities-based encryption scheme. An important feature of this scheme, which is different from other previous ID-based threshold signature schemes, is that it can be applied to situations using not only average personal attributes in social contact but also people's noisy biometric inputs as identities. The security of our scheme in the selective-lD model reduces the limit in the hardness of the Decisional BDH Assumption.

  4. On the security of arbitrated quantum signature schemes

    Science.gov (United States)

    Li, Qin; Li, Chengqing; Wen, Zhonghua; Zhao, Weizhong; Chan, Wai Hong

    2013-01-01

    Due to the potential capability of providing unconditional security, arbitrated quantum signature (AQS) schemes, whose implementation depends on the participation of a trusted third party, received intense attention in the past decade. Recently, some typical AQS schemes were cryptanalyzed and improved. In this paper, we analyze the security property of some AQS schemes and show that all the previous AQS schemes, no matter whether original or improved, are still insecure in the sense that the messages and the corresponding signatures can be exchanged among different receivers, allowing the receivers to deny having accepted the signature of an appointed message. Some further improved methods on the AQS schemes are also discussed.

  5. On the security of arbitrated quantum signature schemes

    CERN Document Server

    Li, Qin; Wen, Zhonghua; Zhao, Weizhong; Chan, W H

    2012-01-01

    Due to potential capability of providing unconditional security, arbitrated quantum signature (AQS) schemes, whose implementation depends on the participation of a trusted third party, received intense attention in the past decade. Recently, some typical AQS schemes were cryptanalyzed and improved. In this paper, we analyze security property of some AQS schemes and show that all the previous AQS schemes, no matter original or improved, are still insecure in the sense that the messages and the corresponding signatures can be exchanged among different receivers, allowing the receivers to deny accepting the signature of an appointed message. Some further improvement methods on the AQS schemes are also discussed.

  6. Sound classification of dwellings - Comparison of schemes in Europe

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2009-01-01

    National sound classification schemes for dwellings exist in nine countries in Europe, and proposals are under preparation in more countries. The schemes specify class criteria concerning several acoustic aspects, the main criteria being about airborne and impact sound insulation between dwellings......, facade sound insulation and installation noise. The quality classes reflect dierent levels of acoustical comfort. The paper presents and compares the sound classification schemes in Europe. The schemes have been implemented and revised gradually since the 1990es. However, due to lack of coordination....... The current variety of descriptors and classes also causes trade barriers. Thus, there is a need to harmonize concepts and other characteristics of the schemes....

  7. Measurability Aspects of the Compactness Theorem for Sample Compression Schemes

    OpenAIRE

    2012-01-01

    It was proved in 1998 by Ben-David and Litman that a concept space has a sample compression scheme of size d if and only if every finite subspace has a sample compression scheme of size d. In the compactness theorem, measurability of the hypotheses of the created sample compression scheme is not guaranteed; at the same time measurability of the hypotheses is a necessary condition for learnability. In this thesis we discuss when a sample compression scheme, created from com- pression schemes o...

  8. A Proxy Blind Signature Scheme Based on ECDLP

    Institute of Scientific and Technical Information of China (English)

    WANGHaiyan; WANGRuchuan

    2005-01-01

    While proxy signature scheme enables an original signer to fully authorize a proxy to sign a message on his or her behalf legally and undeniably, blind signature scheme keeps the message blind from the signer so that the signer cannot make a linkage between the signature and the identity of requester (receiver). Both schemes have been widely applied in the electronic business. A new ECDLP (Elliptic curve discrete problem)-based proxy blind signature scheme is to be proposed in this paper by integrating the security properties of both schemes.

  9. AN IMPROVED REMOTE PASSWORD AUTHENTICATION SCHEME WITH SMART CARD

    Institute of Scientific and Technical Information of China (English)

    Jing Chao

    2012-01-01

    This paper analyzes the security performance of a latest proposed remote two-factor user authentication scheme and proposes an improved scheme based on the dynamic ID to avoid the attacks it suffers.Besides this,in our proposed scheme the password is no longer involved in the calculation of verification phase which makes our scheme more secure and costs less than the old one.At last we analyze the performance of our proposed scheme to prove it provides mutual authentication between the user and the server.Moreover,it also resists password guessing attack,server and user masquerade attack and replay attack effectively.

  10. Quantum election scheme based on anonymous quantum key distribution

    Institute of Scientific and Technical Information of China (English)

    Zhou Rui-Rui; Yang Li

    2012-01-01

    An unconditionally secure authority-certified anonymous quantum key distribution scheme using conjugate coding is presented,based on which we construct a quantum election scheme without the help of an entanglement state.We show that this election scheme ensures the completeness,soundness,privacy,eligibility,unreusability,fairness,and verifiability of a large-scale election in which the administrator and counter are semi-honest.This election scheme can work even if there exist loss and errors in quantum channels.In addition,any irregularity in this scheme is sensible.

  11. A new modified remote user authentication scheme using smart cards

    Institute of Scientific and Technical Information of China (English)

    SHEN Zhong-hua

    2008-01-01

    In 2000, a remote user authentication scheme using smart cards was proposed and the masquerade attacks were proved successful on this scheme. Recently, Kumar has suggested the idea of check digits to overcome the above attacks with a new scheme that removes these threats well. In this paper it is pointed out that the weakness still exists in Kumar's scheme, and the intruder can login to the remote system through having some information. A new scheme which can overcome these attacks and appears more secure and efficient than Kumar's is presented.

  12. Fourth order accurate compact scheme with group velocity control (GVC)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    For solving complex flow field with multi-scale structure higher order accurate schemes are preferred. Among high order schemes the compact schemes have higher resolving efficiency. When the compact and upwind compact schemes are used to solve aerodynamic problems there are numerical oscillations near the shocks. The reason of oscillation production is because of non-uniform group velocity of wave packets in numerical solutions. For improvement of resolution of the shock a parameter function is introduced in compact scheme to control the group velocity. The newly developed method is simple. It has higher accuracy and less stencil of grid points.

  13. An Improved Scalar Costa Scheme Based on Watson Perceptual Model

    Institute of Scientific and Technical Information of China (English)

    QI Kai-yue; CHEN Jian-bo; ZHOU Yi

    2008-01-01

    An improved scalar Costa scheme (SCS) was proposed by using improved Watson perceptual model to adaptively decide quantization step size and scaling factor. The improved scheme equals to embed hiding data based on an actual image. In order to withstand amplitude scaling attack, the Watson perceptual model was redefined, and the improved scheme using the new definition can insure quantization step size in decoder that is proportional to amplitude scaling attack factor. The performance of the improved scheme outperforms that of SCS with fixed quantization step size. The improved scheme combines information theory and visual model.

  14. Improved EPRCA Congestion Control Scheme for ATM Networks

    Directory of Open Access Journals (Sweden)

    Dr. M.Sreenivasulu

    2015-01-01

    Full Text Available Traffic management and congestion control are major issues in Asynchronous Transfer Mode(ATM networks. Congestion arises when traffic in the network is more than offered load. The primary function of congestion control is to ensure good throughput and low delay performance while maintaining a fair allocation of network resources to users. In this paper, Enhanced Proportional Rate based Congestion Avoidance (EPRCA scheme proposed by ATM forum has been considered. But this scheme has limitation of higher cell drop problem for the bursty traffic. Improvements to EPRCA scheme have been proposed to reduce cell drop problem and results of improved EPRCA schemes were analyzed with basic EPRCA scheme.

  15. On the monotonicity of multidimensional finite difference schemes

    Science.gov (United States)

    Kovyrkina, O.; Ostapenko, V.

    2016-10-01

    The classical concept of monotonicity, introduced by Godunov for linear one-dimensional difference schemes, is extended to multidimensional case. Necessary and sufficient conditions of monotonicity are obtained for linear multidimensional difference schemes of first order. The constraints on the numerical viscosity are given that ensure the monotonicity of a difference scheme in the multidimensional case. It is proposed a modification of the second order multidimensional CABARET scheme that preserves the monotonicity of one-dimensional discrete solutions and, as a result, ensures higher smoothness in the computation of multidimensional discontinuous solutions. The results of two-dimensional test computations illustrating the advantages of the modified CABARET scheme are presented.

  16. ON THE CENTRAL RELAXING SCHEMES I:SINGLE CONSERVATION LAWS

    Institute of Scientific and Technical Information of China (English)

    Hua-zhong Tang

    2000-01-01

    In this first paper we present a central relaxing scheme for scalar conservation laws, based on using the local relaxation approximation. Our scheme is obtained without using linear or nonlinear Riemann solvers. A cell entropy inequality is studied for the semidiscrete central relaxing scheme, and a second order MUSCL scheme is shown to be TVD in the zero relaxation limit. The next paper will extend the central relaxing scheme to multi-dimensional systems of conservation laws in curvilinear coordinates, including numerical experiments for 1D and 2D problems.

  17. Scheme Transformations in the Vicinity of an Infrared Fixed Point

    DEFF Research Database (Denmark)

    Ryttov, Thomas; Shrock, Robert

    2012-01-01

    We analyze the effect of scheme transformations in the vicinity of an exact or approximate infrared fixed point in an asymptotically free gauge theory with fermions. We show that there is far less freedom in carrying out such scheme transformations in this case than at an ultraviolet fixed point....... We construct a transformation from the $\\bar{MS}$ scheme to a scheme with a vanishing three-loop term in the $\\beta$ function and use this to assess the scheme dependence of an infrared fixed point in SU($N$) theories with fermions. Implications for the anomalous dimension of the fermion bilinear...

  18. Patterns of Learning in the Accountancy Profession under an Output-Based Continuing Professional Development Scheme

    Science.gov (United States)

    Lindsay, Hilary

    2012-01-01

    Since 2004, professional accountancy bodies in membership of the International Federation of Accountants (IFAC) have been required to adopt mandatory continuing professional development (CPD) schemes. This research explores the learning activities of members of the Institute of Chartered Accountants in England and Wales (ICAEW) which introduced an…

  19. Assessment of shock capturing schemes for discontinuous Galerkin method

    Institute of Scientific and Technical Information of China (English)

    于剑; 阎超; 赵瑞

    2014-01-01

    This paper carries out systematical investigations on the performance of several typical shock-capturing schemes for the discontinuous Galerkin (DG) method, including the total variation bounded (TVB) limiter and three artificial diffusivity schemes (the basis function-based (BF) scheme, the face residual-based (FR) scheme, and the element residual-based (ER) scheme). Shock-dominated flows (the Sod problem, the Shu-Osher problem, the double Mach reflection problem, and the transonic NACA0012 flow) are considered, addressing the issues of accuracy, non-oscillatory property, dependence on user-specified constants, resolution of discontinuities, and capability for steady solutions. Numerical results indicate that the TVB limiter is more efficient and robust, while the artificial diffusivity schemes are able to preserve small-scale flow structures better. In high order cases, the artificial diffusivity schemes have demonstrated superior performance over the TVB limiter.

  20. Multisymplectic five-point scheme for the nonlinear wave equation

    Institute of Scientific and Technical Information of China (English)

    WANG Yushun; WANG Bin; YANG Hongwei; WANG Yunfeng

    2003-01-01

    In this paper, we introduce the multisymplectic structure of the nonlinear wave equation, and prove that the classical five-point scheme for the equation is multisymplectic. Numerical simulations of this multisymplectic scheme on highly oscillatory waves of the nonlinear Klein-Gordon equation and the collisions between kink and anti-kink solitons of the sine-Gordon equation are also provided. The multisymplectic schemes do not need to discrete PDEs in the space first as the symplectic schemes do and preserve not only the geometric structure of the PDEs accurately, but also their first integrals approximately such as the energy, the momentum and so on. Thus the multisymplectic schemes have better numerical stability and long-time numerical behavior than the energy-conserving scheme and the symplectic scheme.