Off-line Scheme Research Articles

513 An adaptive off-line radiation scheme for the treatment of prostate cancer

513 An adaptive off-line radiation scheme for the treatment of prostate cancer

Mass spectrometric approaches for the investigation of dynamic processes in condensed phase.

Mass spectrometry (MS) offers many advantages over other established spectroscopic techniques employed for the investigation of processes in condensed phase. The sensitivity, specificity, and speed afforded by MS-based methods enable to obtain very valuable insights into the mechanism of complex dynamic processes. Off-line methods rely on quenching to halt the progress of the reaction of interest and allow for the implementation of a broad range of analytical procedures for sample fractionation, isolation, or desalting. On the contrary, on-line methods are designed to carry out the real-time monitoring of dynamic processes through a continuous uninterrupted analysis of reaction mixtures, with the only caveat that the sample solutions be directly amenable to the available ionization technique. The utilization of rapid mixing devices in direct connection with a mass spectrometer or included in off-line schemes provides access to the initial moments of a reaction, which can offer very important information about the reaction mechanism. This report summarizes the different off- and on-line strategies developed to study chemical and biochemical reactions in solution and obtain kinetic/mechanistic information. The merits of the various experimental designs, the characteristics of the different instrumental setups, and the factors affecting time resolution are discussed with the aid of specific examples, which highlight the contributions of MS to the different facets of the investigation of dynamic processes in condensed phase.

An Offline Verification Scheme of Skilled Handwritten Forgery Documents using Pressure Characteristics

We introduce an effective approach for offline verification of signatures where the forgeries are skillfully done, i.e., the true and forgery sample appearances are almost alike. Subtle details of temporal information used in online verification are not available offline and are also hard to recover robustly. Thus we take help of the spatial dynamic information like the pen-tip pressure characteristics and emphasize on the extraction of low pressure points. The points result from the ballistic rhythm of a genuine signature which a forgery, however skillful that may be, always lacks. Ten effective features along with low pressure points and pressure multiplication ratio are proposed to make the distinction between a true and a forgery sample. Three different threshold values are also derived for better verification judgements.

Parameter Estimation Algorithms for Hierarchical Distributed Systems

There has been a great deal of research activity in the area of identification of distributed parameter systems over the past two decades. An extensive treatment of off-line schemes ( e.g. , output least squares, estimation error, etc. ) together with a comprehensive survey of the literature can be found in the monograph by Banks and Kunisch [4] . In the case of on-line, or adaptive, schemes, the available literature is less extensive and more recent ( Isermann et al . [7] ). The on-line methods give estimates recursively as the measurements are obtained within the time limit imposed by the sampling period. These include recursive projection algorithm ( Baumeister et al. [5] ), recursive least squares algorithm ( Glentis et al . [6] ), on-line excitation algorithms ( Ludwig et al. [8] ), etc . In this paper an equivalent 2nd order dynamical system is formulated from a given trajectory representing the pattern to be recognised and simulated in order to estimate the parameters for hierarchical distributed systems using 1st and 2nd order dynamics. Recommendations for the best estimation strategy are given.

D-Type learning control for nonlinear time-varying systems with unknown initial states and inputs

In this paper, D-type iterative learning control schemes, which guarantee that the desired output is tracked precisely through iteration, are presented. Both off-line and on-line schemes are considered for a class of nonlinear systems. In both schemes, the learning gain may be time-varying and thus possesses larger scope for adjustment. Specifically, not only the input but also the initial state is iterated in the algorithms, and the output channel is fully nonlinear. Then, sufficient conditions are presented which guarantee the convergence of the proposed algorithms. The desired input and desired state are not assumed to be known a priori. Finally, the results are applied to a robotic system through simulation, which demonstrates the effectiveness of the method.

On the design of efficient RSA-based off-line electronic cash schemes

Electronic cash is arguably one of the most important applications of modern cryptology. There have been two types of electronic cash schemes namely on-line and off-line. In general off-line schemes are more efficient than on-line ones. The two fundamental issues with any off-line electronic cash scheme have been the detection of double spending and provision of anonymity. These issues make the design of secure off-line electronic cash schemes not an easy task. Cut-and-choose technology was one of the first techniques that was introduced to address the issue of double spending in an off-line scheme. However, this technique is not very efficient. Subsequently, other techniques had been proposed to achieve both double spending and client anonymity without using the cut and choose method. These include the works of Brands based on the discrete logarithm and that of Ferguson based on RSA and polynomial secret sharing scheme. In this paper, we propose an improved version of off-line electronic cash scheme based on the Ferguson's protocol. This scheme improves the efficiency by making some of the parameters used in the protocol to be reusable and removes the risk of framing by the bank by hiding the client's identity.

On-line tracing supervisory control of discrete-event dynamic systems based on outlooking

The conventional off-line approach to supervisor synthesis for discrete-event dynamic systems contains critical drawbacks in building overall automata models and calculating the complete control policy for these models. To resolve the complexity of this off-line approach, the supervisory control scheme based on limited lookahead control policies was proposed by Chung et al. and improved by Kumar et al. recently. However, these methods do not guarantee the same closed-loop behavior as an optimal off-line solution. Therefore, we propose an on-line tracing supervisory control scheme founded on component discrete-event models, which ensures the same closed-loop language as an optimal off-line scheme.

Continuous Time Identification of a Helicopter Rotor Blade System

An off-line scheme is used to identify the parameters of a two-dimensional, aerodynamic airfoil model of a helicopter rotor blade system. The continuous time dynamic equations are initially replaced by equivalent integral equations. These integral equations are then approximated as algebraic equations by using orthonormal Walsh Functions (WF) and a least-squares method (via a Frobenius norm) is used to identify the model parameters. Simulation results indicate that this scheme is effective. Un cadre hors-ligne est employe pour identifier les parametres d'une conception bi-dimensionelle d'un "airfoil" aerodynamique d'un systeme de lames rotatrices d'helicoptere. Les equations dynamiques qui sont des fonctions continues de temps sont d'abord remplacees par des equations integrales equivalantes. Puis, ces equations integrales sont approches par des equations algebriques en employant les fonctions de Walsh. Enfin, une methode de moindres carres avec norme de Frobenius est utilise pour identifier les parametres du cadre. Les resultats de la simulation indiquent que la methode est efficace.

New schemes and theoretical analysis of the master-slave family of recursive identification algorithms

An analysis of the Master-Slave family of system identification algorithms is developed for the white noise input case. These methods try to avoid the biased parameter estimation problem of equation error methods in the presence of noisy data, while keeping the quadratic nature of the error variances to be minimized (a feature that is lost with the output error formulation). The Master-Slave techniques may be seen as off-line schemes that construct a sequence of equation error optimization problems, each one based on the solution to the previous one. Some conditions for the stationary points of the iteration are given. Examples are presented for plants with poles close to z = 1 where undesirable attractive convergent points arise. An alternative scheme based on interpolation conditions rather than minimizing error variances is proposed and shown to have a single stationary point corresponding to the plant parameters. Finally, a simplified structure and a lattice algorithm are presented for on-line implementation.

The Master-Slave Family of System Identification Algorithms: Theoretical Results and New Structures

We develop an analysis of the Master-Slave family of system identification algorithms for the white noise input case. The Master-Slave techniques may be seen as off-line schemes that construct a sequence of equation error optimization problems, each one based on the solution to the previous one. Some conditions for the fixed points of the iteration are given. An alternative scheme based on interpolation conditions is proposed.

Scheduling approaches for random job shop flexible manufacturing systems

This research examines the influences that scheduling schemes and the degree of routeing flexibility have on random, job shop flexible manufacturing systems within a static environment. The first factor in the experiment includes three scheduling schemes. Two of these schemes are off-line schemes which schedule many operations prior to actual production. The first of the off-line schemes establishes an overall optimal solution, and the second off-line scheme decomposes the problem into a loading subproblem and a resulting scheduling subproblem and finds optimal solutions to both subproblems. The third scheme uses control policies and dispatching rules to establish a schedule in a real-time mode. The number of alternative machine options (i.e., the degree of routeing flexibility) is a second factor in the experiment and includes eleven levels. In addition, the effects of interaction between scheduling and routeing flexibility on performance are explored.

Interval and recency rank source coding: Two on-line adaptive variable-length schemes

In the schemes presented the encoder maps each message into a codeword in a prefix-free codeword set. In interval encoding the codeword is indexed by the interval since the last previous occurrence of that message, and the codeword set must be countably infinite. In recency rank encoding the codeword is indexed by the number of distinct messages in that interval, and there must be no fewer codewords than messages. The decoder decodes each codeword on receipt. Users need not know message probabilities, but must agree on indexings, of the codeword set in an order of increasing length and of the message set in some arbitrary order. The average codeword length over a communications bout is never much larger than the value for an off-line scheme which maps the j th most frequent message in the bout into the j th shortest codeword in the given set, and is never too much larger than the value for off-line Huffman encoding of messages into the best codeword set for the bout message frequencies. Both schemes can do much better than Huffman coding when successive selections of each message type cluster much more than in the independent case.