Distance Constraint Satisfaction Problems
Bodirsky, Manuel; Dalmau, Victor; Martin, Barnaby; Pinsker, Michael
We study the complexity of constraint satisfaction problems for templates Γ that are first-order definable in ({ Z}; {suc}), the integers with the successor relation. Assuming a widely believed conjecture from finite domain constraint satisfaction (we require the tractability conjecture by Bulatov, Jeavons and Krokhin in the special case of transitive finite templates), we provide a full classification for the case that Γ is locally finite (i.e., the Gaifman graph of Γ has finite degree). We show that one of the following is true: The structure Γ is homomorphically equivalent to a structure with a certain majority polymorphism (which we call modular median) and CSP(Γ) can be solved in polynomial time, or Γ is homomorphically equivalent to a finite transitive structure, or CSP(Γ) is NP-complete.
Relaxations of semiring constraint satisfaction problems
CSIR Research Space (South Africa)
Leenen, L
2007-03-01
Full Text Available The Semiring Constraint Satisfaction Problem (SCSP) framework is a popular approach for the representation of partial constraint satisfaction problems. In this framework preferences can be associated with tuples of values of the variable domains...
Constraint satisfaction problems CSP formalisms and techniques
Ghedira, Khaled
2013-01-01
A Constraint Satisfaction Problem (CSP) consists of a set of variables, a domain of values for each variable and a set of constraints. The objective is to assign a value for each variable such that all constraints are satisfied. CSPs continue to receive increased attention because of both their high complexity and their omnipresence in academic, industrial and even real-life problems. This is why they are the subject of intense research in both artificial intelligence and operations research. This book introduces the classic CSP and details several extensions/improvements of both formalisms a
Branch and bound algorithms to solve semiring constraint satisfaction problems
CSIR Research Space (South Africa)
Leenen, L
2008-12-01
Full Text Available The Semiring Constraint Satisfaction Problem (SCSP) framework is a popular approach for the representation of partial constraint satisfaction problems. Considerable research has been done in solving SCSPs, but limited work has been done in building...
Algorithms and ordering heuristics for distributed constraint satisfaction problems
Wahbi , Mohamed
2013-01-01
DisCSP (Distributed Constraint Satisfaction Problem) is a general framework for solving distributed problems arising in Distributed Artificial Intelligence.A wide variety of problems in artificial intelligence are solved using the constraint satisfaction problem paradigm. However, there are several applications in multi-agent coordination that are of a distributed nature. In this type of application, the knowledge about the problem, that is, variables and constraints, may be logically or geographically distributed among physical distributed agents. This distribution is mainly due to p
An Extensive Evaluation of Portfolio Approaches for Constraint Satisfaction Problems
Directory of Open Access Journals (Sweden)
Roberto Amadini
2016-06-01
Full Text Available In the context of Constraint Programming, a portfolio approach exploits the complementary strengths of a portfolio of different constraint solvers. The goal is to predict and run the best solver(s of the portfolio for solving a new, unseen problem. In this work we reproduce, simulate, and evaluate the performance of different portfolio approaches on extensive benchmarks of Constraint Satisfaction Problems. Empirical results clearly show the benefits of portfolio solvers in terms of both solved instances and solving time.
Correlation-based decimation in constraint satisfaction problems
International Nuclear Information System (INIS)
Higuchi, Saburo; Mezard, Marc
2010-01-01
We study hard constraint satisfaction problems using some decimation algorithms based on mean-field approximations. The message-passing approach is used to estimate, beside the usual one-variable marginals, the pair correlation functions. The identification of strongly correlated pairs allows to use a new decimation procedure, where the relative orientation of a pair of variables is fixed. We apply this novel decimation to locked occupation problems, a class of hard constraint satisfaction problems where the usual belief-propagation guided decimation performs poorly. The pair-decimation approach provides a significant improvement.
Constraint satisfaction problems with isolated solutions are hard
International Nuclear Information System (INIS)
Zdeborová, Lenka; Mézard, Marc
2008-01-01
We study the phase diagram and the algorithmic hardness of the random 'locked' constraint satisfaction problems, and compare them to the commonly studied 'non-locked' problems like satisfiability of Boolean formulae or graph coloring. The special property of the locked problems is that clusters of solutions are isolated points. This simplifies significantly the determination of the phase diagram, which makes the locked problems particularly appealing from the mathematical point of view. On the other hand, we show empirically that the clustered phase of these problems is extremely hard from the algorithmic point of view: the best known algorithms all fail to find solutions. Our results suggest that the easy/hard transition (for currently known algorithms) in the locked problems coincides with the clustering transition. These should thus be regarded as new benchmarks of really hard constraint satisfaction problems
Experimental Matching of Instances to Heuristics for Constraint Satisfaction Problems.
Moreno-Scott, Jorge Humberto; Ortiz-Bayliss, José Carlos; Terashima-Marín, Hugo; Conant-Pablos, Santiago Enrique
2016-01-01
Constraint satisfaction problems are of special interest for the artificial intelligence and operations research community due to their many applications. Although heuristics involved in solving these problems have largely been studied in the past, little is known about the relation between instances and the respective performance of the heuristics used to solve them. This paper focuses on both the exploration of the instance space to identify relations between instances and good performing heuristics and how to use such relations to improve the search. Firstly, the document describes a methodology to explore the instance space of constraint satisfaction problems and evaluate the corresponding performance of six variable ordering heuristics for such instances in order to find regions on the instance space where some heuristics outperform the others. Analyzing such regions favors the understanding of how these heuristics work and contribute to their improvement. Secondly, we use the information gathered from the first stage to predict the most suitable heuristic to use according to the features of the instance currently being solved. This approach proved to be competitive when compared against the heuristics applied in isolation on both randomly generated and structured instances of constraint satisfaction problems.
CSIR Research Space (South Africa)
Leenen, L
2007-12-01
Full Text Available The authors present a variant of the Weighted Maximum Satisfiability Problem (Weighted Max-SAT), which is a modeling of the Semiring Constraint Satisfaction framework. They show how to encode a Semiring Constraint Satisfaction Problem (SCSP...
Quiet planting in the locked constraints satisfaction problems
Energy Technology Data Exchange (ETDEWEB)
Zdeborova, Lenka [Los Alamos National Laboratory; Krzakala, Florent [Los Alamos National Laboratory
2009-01-01
We study the planted ensemble of locked constraint satisfaction problems. We describe the connection between the random and planted ensembles. The use of the cavity method is combined with arguments from reconstruction on trees and first and second moment considerations; in particular the connection with the reconstruction on trees appears to be crucial. Our main result is the location of the hard region in the planted ensemble, thus providing hard satisfiable benchmarks. In a part of that hard region instances have with high probability a single satisfying assignment.
Solving Constraint Satisfaction Problems with Networks of Spiking Neurons.
Jonke, Zeno; Habenschuss, Stefan; Maass, Wolfgang
2016-01-01
Network of neurons in the brain apply-unlike processors in our current generation of computer hardware-an event-based processing strategy, where short pulses (spikes) are emitted sparsely by neurons to signal the occurrence of an event at a particular point in time. Such spike-based computations promise to be substantially more power-efficient than traditional clocked processing schemes. However, it turns out to be surprisingly difficult to design networks of spiking neurons that can solve difficult computational problems on the level of single spikes, rather than rates of spikes. We present here a new method for designing networks of spiking neurons via an energy function. Furthermore, we show how the energy function of a network of stochastically firing neurons can be shaped in a transparent manner by composing the networks of simple stereotypical network motifs. We show that this design approach enables networks of spiking neurons to produce approximate solutions to difficult (NP-hard) constraint satisfaction problems from the domains of planning/optimization and verification/logical inference. The resulting networks employ noise as a computational resource. Nevertheless, the timing of spikes plays an essential role in their computations. Furthermore, networks of spiking neurons carry out for the Traveling Salesman Problem a more efficient stochastic search for good solutions compared with stochastic artificial neural networks (Boltzmann machines) and Gibbs sampling.
Solving constraint satisfaction problems with networks of spiking neurons
Directory of Open Access Journals (Sweden)
Zeno eJonke
2016-03-01
Full Text Available Network of neurons in the brain apply – unlike processors in our current generation ofcomputer hardware – an event-based processing strategy, where short pulses (spikes areemitted sparsely by neurons to signal the occurrence of an event at a particular point intime. Such spike-based computations promise to be substantially more power-efficient thantraditional clocked processing schemes. However it turned out to be surprisingly difficult todesign networks of spiking neurons that can solve difficult computational problems on the levelof single spikes (rather than rates of spikes. We present here a new method for designingnetworks of spiking neurons via an energy function. Furthermore we show how the energyfunction of a network of stochastically firing neurons can be shaped in a quite transparentmanner by composing the networks of simple stereotypical network motifs. We show that thisdesign approach enables networks of spiking neurons to produce approximate solutions todifficult (NP-hard constraint satisfaction problems from the domains of planning/optimizationand verification/logical inference. The resulting networks employ noise as a computationalresource. Nevertheless the timing of spikes (rather than just spike rates plays an essential rolein their computations. Furthermore, networks of spiking neurons carry out for the Traveling Salesman Problem a more efficient stochastic search for good solutions compared with stochastic artificial neural networks (Boltzmann machines and Gibbs sampling.
Exploring the Impact of Early Decisions in Variable Ordering for Constraint Satisfaction Problems
Ortiz-Bayliss, José Carlos; Amaya, Ivan; Conant-Pablos, Santiago Enrique; Terashima-Marín, Hugo
2018-01-01
When solving constraint satisfaction problems (CSPs), it is a common practice to rely on heuristics to decide which variable should be instantiated at each stage of the search. But, this ordering influences the search cost. Even so, and to the best of our knowledge, no earlier work has dealt with how first variable orderings affect the overall cost. In this paper, we explore the cost of finding high-quality orderings of variables within constraint satisfaction problems. We also study differen...
Sitek, Paweł; Wikarek, Jarosław
2016-01-01
This paper proposes a hybrid programming framework for modeling and solving of constraint satisfaction problems (CSPs) and constraint optimization problems (COPs). Two paradigms, CLP (constraint logic programming) and MP (mathematical programming), are integrated in the framework. The integration is supplemented with the original method of problem transformation, used in the framework as a presolving method. The transformation substantially reduces the feasible solution space. The framework a...
Solving the Weighted Constraint Satisfaction Problems Via the Neural Network Approach
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Khalid Haddouch
2016-09-01
Full Text Available A wide variety of real world optimization problems can be modelled as Weighted Constraint Satisfaction Problems (WCSPs. In this paper, we model this problem in terms of in original 0-1 quadratic programming subject to leaner constraints. View it performance, we use the continuous Hopfield network to solve the obtained model basing on original energy function. To validate our model, we solve several instance of benchmarking WCSP. In this regard, our approach recognizes the optimal solution of the said instances.
A Hybrid Autonomic Computing-Based Approach to Distributed Constraint Satisfaction Problems
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Abhishek Bhatia
2015-03-01
Full Text Available Distributed constraint satisfaction problems (DisCSPs are among the widely endeavored problems using agent-based simulation. Fernandez et al. formulated sensor and mobile tracking problem as a DisCSP, known as SensorDCSP In this paper, we adopt a customized ERE (environment, reactive rules and entities algorithm for the SensorDCSP, which is otherwise proven as a computationally intractable problem. An amalgamation of the autonomy-oriented computing (AOC-based algorithm (ERE and genetic algorithm (GA provides an early solution of the modeled DisCSP. Incorporation of GA into ERE facilitates auto-tuning of the simulation parameters, thereby leading to an early solution of constraint satisfaction. This study further contributes towards a model, built up in the NetLogo simulation environment, to infer the efficacy of the proposed approach.
Directory of Open Access Journals (Sweden)
Paweł Sitek
2016-01-01
Full Text Available This paper proposes a hybrid programming framework for modeling and solving of constraint satisfaction problems (CSPs and constraint optimization problems (COPs. Two paradigms, CLP (constraint logic programming and MP (mathematical programming, are integrated in the framework. The integration is supplemented with the original method of problem transformation, used in the framework as a presolving method. The transformation substantially reduces the feasible solution space. The framework automatically generates CSP and COP models based on current values of data instances, questions asked by a user, and set of predicates and facts of the problem being modeled, which altogether constitute a knowledge database for the given problem. This dynamic generation of dedicated models, based on the knowledge base, together with the parameters changing externally, for example, the user’s questions, is the implementation of the autonomous search concept. The models are solved using the internal or external solvers integrated with the framework. The architecture of the framework as well as its implementation outline is also included in the paper. The effectiveness of the framework regarding the modeling and solution search is assessed through the illustrative examples relating to scheduling problems with additional constrained resources.
Entropy landscape and non-Gibbs solutions in constraint satisfaction problems
International Nuclear Information System (INIS)
Dall'Asta, L.; Ramezanpour, A.; Zecchina, R.
2008-05-01
We study the entropy landscape of solutions for the bicoloring problem in random graphs, a representative difficult constraint satisfaction problem. Our goal is to classify which type of clusters of solutions are addressed by different algorithms. In the first part of the study we use the cavity method to obtain the number of clusters with a given internal entropy and determine the phase diagram of the problem, e.g. dynamical, rigidity and SAT-UNSAT transitions. In the second part of the paper we analyze different algorithms and locate their behavior in the entropy landscape of the problem. For instance we show that a smoothed version of a decimation strategy based on Belief Propagation is able to find solutions belonging to sub-dominant clusters even beyond the so called rigidity transition where the thermodynamically relevant clusters become frozen. These non-equilibrium solutions belong to the most probable unfrozen clusters. (author)
A neural network approach to breast cancer diagnosis as a constraint satisfaction problem
International Nuclear Information System (INIS)
Tourassi, Georgia D.; Markey, Mia K.; Lo, Joseph Y.; Floyd, Carey E. Jr.
2001-01-01
A constraint satisfaction neural network (CSNN) approach is proposed for breast cancer diagnosis using mammographic and patient history findings. Initially, the diagnostic decision to biopsy was formulated as a constraint satisfaction problem. Then, an associative memory type neural network was applied to solve the problem. The proposed network has a flexible, nonhierarchical architecture that allows it to operate not only as a predictive tool but also as an analysis tool for knowledge discovery of association rules. The CSNN was developed and evaluated using a database of 500 nonpalpable breast lesions with definitive histopathological diagnosis. The CSNN diagnostic performance was evaluated using receiver operating characteristic analysis (ROC). The results of the study showed that the CSNN ROC area index was 0.84±0.02. The CSNN predictive performance is competitive with that achieved by experienced radiologists and backpropagation artificial neural networks (BP-ANNs) presented before. Furthermore, the study illustrates how CSNN can be used as a knowledge discovery tool overcoming some of the well-known limitations of BP-ANNs
Exploring the Impact of Early Decisions in Variable Ordering for Constraint Satisfaction Problems
Directory of Open Access Journals (Sweden)
José Carlos Ortiz-Bayliss
2018-01-01
Full Text Available When solving constraint satisfaction problems (CSPs, it is a common practice to rely on heuristics to decide which variable should be instantiated at each stage of the search. But, this ordering influences the search cost. Even so, and to the best of our knowledge, no earlier work has dealt with how first variable orderings affect the overall cost. In this paper, we explore the cost of finding high-quality orderings of variables within constraint satisfaction problems. We also study differences among the orderings produced by some commonly used heuristics and the way bad first decisions affect the search cost. One of the most important findings of this work confirms the paramount importance of first decisions. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. We propose a simple method to improve early decisions of heuristics. By using it, performance of heuristics increases.
Exploring the Impact of Early Decisions in Variable Ordering for Constraint Satisfaction Problems.
Ortiz-Bayliss, José Carlos; Amaya, Ivan; Conant-Pablos, Santiago Enrique; Terashima-Marín, Hugo
2018-01-01
When solving constraint satisfaction problems (CSPs), it is a common practice to rely on heuristics to decide which variable should be instantiated at each stage of the search. But, this ordering influences the search cost. Even so, and to the best of our knowledge, no earlier work has dealt with how first variable orderings affect the overall cost. In this paper, we explore the cost of finding high-quality orderings of variables within constraint satisfaction problems. We also study differences among the orderings produced by some commonly used heuristics and the way bad first decisions affect the search cost. One of the most important findings of this work confirms the paramount importance of first decisions. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. Another one is the evidence that many of the existing variable ordering heuristics fail to appropriately select the first variable to instantiate. We propose a simple method to improve early decisions of heuristics. By using it, performance of heuristics increases.
A message-passing approach to random constraint satisfaction problems with growing domains
International Nuclear Information System (INIS)
Zhao, Chunyan; Zheng, Zhiming; Zhou, Haijun; Xu, Ke
2011-01-01
Message-passing algorithms based on belief propagation (BP) are implemented on a random constraint satisfaction problem (CSP) referred to as model RB, which is a prototype of hard random CSPs with growing domain size. In model RB, the number of candidate discrete values (the domain size) of each variable increases polynomially with the variable number N of the problem formula. Although the satisfiability threshold of model RB is exactly known, finding solutions for a single problem formula is quite challenging and attempts have been limited to cases of N ∼ 10 2 . In this paper, we propose two different kinds of message-passing algorithms guided by BP for this problem. Numerical simulations demonstrate that these algorithms allow us to find a solution for random formulas of model RB with constraint tightness slightly less than p cr , the threshold value for the satisfiability phase transition. To evaluate the performance of these algorithms, we also provide a local search algorithm (random walk) as a comparison. Besides this, the simulated time dependence of the problem size N and the entropy of the variables for growing domain size are discussed
Directory of Open Access Journals (Sweden)
Botond Molnár
Full Text Available There has been a long history of using neural networks for combinatorial optimization and constraint satisfaction problems. Symmetric Hopfield networks and similar approaches use steepest descent dynamics, and they always converge to the closest local minimum of the energy landscape. For finding global minima additional parameter-sensitive techniques are used, such as classical simulated annealing or the so-called chaotic simulated annealing, which induces chaotic dynamics by addition of extra terms to the energy landscape. Here we show that asymmetric continuous-time neural networks can solve constraint satisfaction problems without getting trapped in non-solution attractors. We concentrate on a model solving Boolean satisfiability (k-SAT, which is a quintessential NP-complete problem. There is a one-to-one correspondence between the stable fixed points of the neural network and the k-SAT solutions and we present numerical evidence that limit cycles may also be avoided by appropriately choosing the parameters of the model. This optimal parameter region is fairly independent of the size and hardness of instances, this way parameters can be chosen independently of the properties of problems and no tuning is required during the dynamical process. The model is similar to cellular neural networks already used in CNN computers. On an analog device solving a SAT problem would take a single operation: the connection weights are determined by the k-SAT instance and starting from any initial condition the system searches until finding a solution. In this new approach transient chaotic behavior appears as a natural consequence of optimization hardness and not as an externally induced effect.
Using Stochastic Spiking Neural Networks on SpiNNaker to Solve Constraint Satisfaction Problems
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Gabriel A. Fonseca Guerra
2017-12-01
Full Text Available Constraint satisfaction problems (CSP are at the core of numerous scientific and technological applications. However, CSPs belong to the NP-complete complexity class, for which the existence (or not of efficient algorithms remains a major unsolved question in computational complexity theory. In the face of this fundamental difficulty heuristics and approximation methods are used to approach instances of NP (e.g., decision and hard optimization problems. The human brain efficiently handles CSPs both in perception and behavior using spiking neural networks (SNNs, and recent studies have demonstrated that the noise embedded within an SNN can be used as a computational resource to solve CSPs. Here, we provide a software framework for the implementation of such noisy neural solvers on the SpiNNaker massively parallel neuromorphic hardware, further demonstrating their potential to implement a stochastic search that solves instances of P and NP problems expressed as CSPs. This facilitates the exploration of new optimization strategies and the understanding of the computational abilities of SNNs. We demonstrate the basic principles of the framework by solving difficult instances of the Sudoku puzzle and of the map color problem, and explore its application to spin glasses. The solver works as a stochastic dynamical system, which is attracted by the configuration that solves the CSP. The noise allows an optimal exploration of the space of configurations, looking for the satisfiability of all the constraints; if applied discontinuously, it can also force the system to leap to a new random configuration effectively causing a restart.
Using Stochastic Spiking Neural Networks on SpiNNaker to Solve Constraint Satisfaction Problems.
Fonseca Guerra, Gabriel A; Furber, Steve B
2017-01-01
Constraint satisfaction problems (CSP) are at the core of numerous scientific and technological applications. However, CSPs belong to the NP-complete complexity class, for which the existence (or not) of efficient algorithms remains a major unsolved question in computational complexity theory. In the face of this fundamental difficulty heuristics and approximation methods are used to approach instances of NP (e.g., decision and hard optimization problems). The human brain efficiently handles CSPs both in perception and behavior using spiking neural networks (SNNs), and recent studies have demonstrated that the noise embedded within an SNN can be used as a computational resource to solve CSPs. Here, we provide a software framework for the implementation of such noisy neural solvers on the SpiNNaker massively parallel neuromorphic hardware, further demonstrating their potential to implement a stochastic search that solves instances of P and NP problems expressed as CSPs. This facilitates the exploration of new optimization strategies and the understanding of the computational abilities of SNNs. We demonstrate the basic principles of the framework by solving difficult instances of the Sudoku puzzle and of the map color problem, and explore its application to spin glasses. The solver works as a stochastic dynamical system, which is attracted by the configuration that solves the CSP. The noise allows an optimal exploration of the space of configurations, looking for the satisfiability of all the constraints; if applied discontinuously, it can also force the system to leap to a new random configuration effectively causing a restart.
The dose-volume constraint satisfaction problem for inverse treatment planning with field segments
International Nuclear Information System (INIS)
Michalski, Darek; Xiao, Ying; Censor, Yair; Galvin, James M
2004-01-01
The prescribed goals of radiation treatment planning are often expressed in terms of dose-volume constraints. We present a novel formulation of a dose-volume constraint satisfaction search for the discretized radiation therapy model. This approach does not rely on any explicit cost function. Inverse treatment planning uses the aperture-based approach with predefined, according to geometric rules, segmental fields. The solver utilizes the simultaneous version of the cyclic subgradient projection algorithm. This is a deterministic iterative method designed for solving the convex feasibility problems. A prescription is expressed with the set of inequalities imposed on the dose at the voxel resolution. Additional constraint functions control the compliance with selected points of the expected cumulative dose-volume histograms. The performance of this method is tested on prostate and head-and-neck cases. The relationships with other models and algorithms of similar conceptual origin are discussed. The demonstrated advantages of the method are: the equivalence of the algorithmic and prescription parameters, the intuitive setup of free parameters, and the improved speed of the method as compared to similar iterative as well as other techniques. The technique reported here will deliver approximate solutions for inconsistent prescriptions
From near to eternity: Spin-glass planting, tiling puzzles, and constraint-satisfaction problems
Hamze, Firas; Jacob, Darryl C.; Ochoa, Andrew J.; Perera, Dilina; Wang, Wenlong; Katzgraber, Helmut G.
2018-04-01
We present a methodology for generating Ising Hamiltonians of tunable complexity and with a priori known ground states based on a decomposition of the model graph into edge-disjoint subgraphs. The idea is illustrated with a spin-glass model defined on a cubic lattice, where subproblems, whose couplers are restricted to the two values {-1 ,+1 } , are specified on unit cubes and are parametrized by their local degeneracy. The construction is shown to be equivalent to a type of three-dimensional constraint-satisfaction problem known as the tiling puzzle. By varying the proportions of subproblem types, the Hamiltonian can span a dramatic range of typical computational complexity, from fairly easy to many orders of magnitude more difficult than prototypical bimodal and Gaussian spin glasses in three space dimensions. We corroborate this behavior via experiments with different algorithms and discuss generalizations and extensions to different types of graphs.
Local entropy as a measure for sampling solutions in constraint satisfaction problems
International Nuclear Information System (INIS)
Baldassi, Carlo; Ingrosso, Alessandro; Lucibello, Carlo; Saglietti, Luca; Zecchina, Riccardo
2016-01-01
We introduce a novel entropy-driven Monte Carlo (EdMC) strategy to efficiently sample solutions of random constraint satisfaction problems (CSPs). First, we extend a recent result that, using a large-deviation analysis, shows that the geometry of the space of solutions of the binary perceptron learning problem (a prototypical CSP), contains regions of very high-density of solutions. Despite being sub-dominant, these regions can be found by optimizing a local entropy measure. Building on these results, we construct a fast solver that relies exclusively on a local entropy estimate, and can be applied to general CSPs. We describe its performance not only for the perceptron learning problem but also for the random K-satisfiabilty problem (another prototypical CSP with a radically different structure), and show numerically that a simple zero-temperature Metropolis search in the smooth local entropy landscape can reach sub-dominant clusters of optimal solutions in a small number of steps, while standard Simulated Annealing either requires extremely long cooling procedures or just fails. We also discuss how the EdMC can heuristically be made even more efficient for the cases we studied. (paper: disordered systems, classical and quantum)
DEFF Research Database (Denmark)
Gutin, Gregory; Van Iersel, Leo; Mnich, Matthias
2010-01-01
A ternary Permutation-CSP is specified by a subset Π of the symmetric group S3. An instance of such a problem consists of a set of variables V and a multiset of constraints, which are ordered triples of distinct variables of V. The objective is to find a linear ordering α of V that maximizes...... the number of triples whose rearrangement (under α) follows a permutation in Π. We prove that all ternary Permutation-CSPs parameterized above average have kernels with quadratic numbers of variables....
Localization of a Vehicle: A Dynamic Interval Constraint Satisfaction Problem-Based Approach
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Kangni Kueviakoe
2018-01-01
Full Text Available This paper introduces a new interval constraint propagation (ICP approach dealing with the real-time vehicle localization problem. Bayesian methods like extended Kalman filter (EKF are classically used to achieve vehicle localization. ICP is an alternative which provides guaranteed localization results rather than probabilities. Our approach assumes that all models and measurement errors are bounded within known limits without any other hypotheses on the probability distribution. The proposed algorithm uses a low-level consistency algorithm and has been validated with an outdoor vehicle equipped with a GPS receiver, a gyro, and odometers. Results have been compared to EKF and other ICP methods such as hull consistency (HC4 and 3-bound (3B algorithms. Both consistencies of EKF and our algorithm have been experimentally studied.
The constraints satisfaction problem approach in the design of an architectural functional layout
Zawidzki, Machi; Tateyama, Kazuyoshi; Nishikawa, Ikuko
2011-09-01
A design support system with a new strategy for finding the optimal functional configurations of rooms for architectural layouts is presented. A set of configurations satisfying given constraints is generated and ranked according to multiple objectives. The method can be applied to problems in architectural practice, urban or graphic design-wherever allocation of related geometrical elements of known shape is optimized. Although the methodology is shown using simplified examples-a single story residential building with two apartments each having two rooms-the results resemble realistic functional layouts. One example of a practical size problem of a layout of three apartments with a total of 20 rooms is demonstrated, where the generated solution can be used as a base for a realistic architectural blueprint. The discretization of design space is discussed, followed by application of a backtrack search algorithm used for generating a set of potentially 'good' room configurations. Next the solutions are classified by a machine learning method (FFN) as 'proper' or 'improper' according to the internal communication criteria. Examples of interactive ranking of the 'proper' configurations according to multiple criteria and choosing 'the best' ones are presented. The proposed framework is general and universal-the criteria, parameters and weights can be individually defined by a user and the search algorithm can be adjusted to a specific problem.
Graphical constraints: a graphical user interface for constraint problems
Vieira, Nelson Manuel Marques
2015-01-01
A constraint satisfaction problem is a classical artificial intelligence paradigm characterized by a set of variables (each variable with an associated domain of possible values), and a set of constraints that specify relations among subsets of these variables. Solutions are assignments of values to all variables that satisfy all the constraints. Many real world problems may be modelled by means of constraints. The range of problems that can use this representation is very diverse and embrace...
Cognitive Dissonance Reduction as Constraint Satisfaction.
Shultz, Thomas R.; Lepper, Mark R.
1996-01-01
It is argued that the reduction of cognitive dissonance can be viewed as a constraint satisfaction problem, and a computational model of the process of consonance seeking is proposed. Simulations from this model matched psychological findings from the insufficient justification and free-choice paradigms of cognitive dissonance theory. (SLD)
Medical image segmentation by means of constraint satisfaction neural network
International Nuclear Information System (INIS)
Chen, C.T.; Tsao, C.K.; Lin, W.C.
1990-01-01
This paper applies the concept of constraint satisfaction neural network (CSNN) to the problem of medical image segmentation. Constraint satisfaction (or constraint propagation), the procedure to achieve global consistency through local computation, is an important paradigm in artificial intelligence. CSNN can be viewed as a three-dimensional neural network, with the two-dimensional image matrix as its base, augmented by various constraint labels for each pixel. These constraint labels can be interpreted as the connections and the topology of the neural network. Through parallel and iterative processes, the CSNN will approach a solution that satisfies the given constraints thus providing segmented regions with global consistency
Multi-Objective Constraint Satisfaction for Mobile Robot Area Defense
2010-03-01
David A. Van Veldhuizen . Evo- lutionary Algorithms for Solving Multi-Objective Problems. Springer, New York, NY, 2nd edition, 2007. [9] Dean, Thomas...J.I. van Hemert, E. Marchiori, and A. G. Steenbeek. “Solving Binary Constraint Satisfaction Problems using Evolutionary Algorithms with an Adaptive
Medical image segmentation by a constraint satisfaction neural network
International Nuclear Information System (INIS)
Chen, C.T.; Tsao, E.C.K.; Lin, W.C.
1991-01-01
This paper proposes a class of Constraint Satisfaction Neural Networks (CSNNs) for solving the problem of medical image segmentation which can be formulated as a Constraint Satisfaction Problem (CSP). A CSNN consists of a set of objects, a set of labels for each object, a collection of constraint relations linking the labels of neighboring objects, and a topological constraint describing the neighborhood relationship among various objects. Each label for a particular object indicates one possible interpretation for that object. The CSNN can be viewed as a collection of neurons that interconnect with each other. The connections and the topology of a CSNN are used to represent the constraints in a CSP. The mechanism of the neural network is to find a solution that satisfies all the constraints in order to achieve a global consistency. The final solution outlines segmented areas and simultaneously satisfies all the constraints. This technique has been applied to medical images and the results show that this CSNN method is a very promising approach for image segmentation
Constraint-based scheduling applying constraint programming to scheduling problems
Baptiste, Philippe; Nuijten, Wim
2001-01-01
Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...
Nonlinear Model Predictive Control with Constraint Satisfactions for a Quadcopter
Wang, Ye; Ramirez-Jaime, Andres; Xu, Feng; Puig, Vicenç
2017-01-01
This paper presents a nonlinear model predictive control (NMPC) strategy combined with constraint satisfactions for a quadcopter. The full dynamics of the quadcopter describing the attitude and position are nonlinear, which are quite sensitive to changes of inputs and disturbances. By means of constraint satisfactions, partial nonlinearities and modeling errors of the control-oriented model of full dynamics can be transformed into the inequality constraints. Subsequently, the quadcopter can be controlled by an NMPC controller with the updated constraints generated by constraint satisfactions. Finally, the simulation results applied to a quadcopter simulator are provided to show the effectiveness of the proposed strategy.
Onoyama, Takashi; Maekawa, Takuya; Kubota, Sen; Tsuruta, Setuso; Komoda, Norihisa
To build a cooperative logistics network covering multiple enterprises, a planning method that can build a long-distance transportation network is required. Many strict constraints are imposed on this type of problem. To solve these strict-constraint problems, a selfish constraint satisfaction genetic algorithm (GA) is proposed. In this GA, each gene of an individual satisfies only its constraint selfishly, disregarding the constraints of other genes in the same individuals. Moreover, a constraint pre-checking method is also applied to improve the GA convergence speed. The experimental result shows the proposed method can obtain an accurate solution in a practical response time.
Generalizing Backtrack-Free Search: A Framework for Search-Free Constraint Satisfaction
Jonsson, Ari K.; Frank, Jeremy
2000-01-01
Tractable classes of constraint satisfaction problems are of great importance in artificial intelligence. Identifying and taking advantage of such classes can significantly speed up constraint problem solving. In addition, tractable classes are utilized in applications where strict worst-case performance guarantees are required, such as constraint-based plan execution. In this work, we present a formal framework for search-free (backtrack-free) constraint satisfaction. The framework is based on general procedures, rather than specific propagation techniques, and thus generalizes existing techniques in this area. We also relate search-free problem solving to the notion of decision sets and use the result to provide a constructive criterion that is sufficient to guarantee search-free problem solving.
Optimizing Concurrent M3-Transactions: A Fuzzy Constraint Satisfaction Approach
Directory of Open Access Journals (Sweden)
Peng LI
2004-10-01
Full Text Available Due to the high connectivity and great convenience, many E-commerce application systems have a high transaction volume. Consequently, the system state changes rapidly and it is likely that customers issue transactions based on out-of-date state information. Thus, the potential of transaction abortion increases greatly. To address this problem, we proposed an M3-transaction model. An M3-transaction is a generalized transaction where users can issue their preferences in a request by specifying multiple criteria and optional data resources simultaneously within one transaction. In this paper, we introduce the transaction grouping and group evaluation techniques. We consider evaluating a group of M3-transactions arrived to the system within a short duration together. The system makes optimal decisions in allocating data to transactions to achieve better customer satisfaction and lower transaction failure rate. We apply the fuzzy constraint satisfaction approach for decision-making. We also conduct experimental studies to evaluate the performance of our approach. The results show that the M3-transaction with group evaluation is more resilient to failure and yields much better performance than the traditional transaction model.
Yang, S; Wang, D
2000-01-01
This paper presents a constraint satisfaction adaptive neural network, together with several heuristics, to solve the generalized job-shop scheduling problem, one of NP-complete constraint satisfaction problems. The proposed neural network can be easily constructed and can adaptively adjust its weights of connections and biases of units based on the sequence and resource constraints of the job-shop scheduling problem during its processing. Several heuristics that can be combined with the neural network are also presented. In the combined approaches, the neural network is used to obtain feasible solutions, the heuristic algorithms are used to improve the performance of the neural network and the quality of the obtained solutions. Simulations have shown that the proposed neural network and its combined approaches are efficient with respect to the quality of solutions and the solving speed.
Least Squares Problems with Absolute Quadratic Constraints
Directory of Open Access Journals (Sweden)
R. Schöne
2012-01-01
Full Text Available This paper analyzes linear least squares problems with absolute quadratic constraints. We develop a generalized theory following Bookstein's conic-fitting and Fitzgibbon's direct ellipse-specific fitting. Under simple preconditions, it can be shown that a minimum always exists and can be determined by a generalized eigenvalue problem. This problem is numerically reduced to an eigenvalue problem by multiplications of Givens' rotations. Finally, four applications of this approach are presented.
Constraint-based solver for the Military unit path finding problem
CSIR Research Space (South Africa)
Leenen, L
2010-04-01
Full Text Available -based approach because it requires flexibility in modelling. The authors formulate the MUPFP as a constraint satisfaction problem and a constraint-based extension of the search algorithm. The concept demonstrator uses a provided map, for example taken from Google...
CONSTRAINTS AND PROBLEMS OF INTERNET SERVICES IN ...
African Journals Online (AJOL)
In spite of the benefits of the Internet to learning, teaching and research a number of difficulties still bedevil the provision of services in Nigeria. The objective of this study was to examine the constraints and problems of Internet Services at the Obafemi Awolowo University, Ile-Ife. Questionnaires were administered to ...
[Problem-solving strategies and marital satisfaction].
Kriegelewicz, Olga
2006-01-01
This study investigated the relation between problem-solving strategies in the marital conflict and marital satisfaction. Four problem-solving strategies (Dialogue, Loyalty, Escalation of conflict and Withdrawal) were measured by the Problem-Solving Strategies Inventory, in two versions: self-report and report of partners' perceived behaviour. This measure refers to the concept of Rusbult, Johnson and Morrow, and meets high standards of reliability (alpha Cronbach from alpha = 0.78 to alpha = 0.94) and validity. Marital satisfaction was measured by Marriage Success Scale. The sample was composed of 147 marital couples. The study revealed that satisfied couples, in comparison with non-satisfied couples, tend to use constructive problem-solving strategies (Dialogue and Loyalty). They rarely use destructive strategies like Escalation of conflict or Withdrawal. Dialogue is the strategy connected with satisfaction in a most positive manner. These might be very important guidelines to couples' psychotherapy. Loyalty to oneself is a significant positive predictor of male satisfaction is also own Loyalty. The study shows that constructive attitudes are the most significant predictors of marriage satisfaction. It is therefore worth concentrating mostly on them in the psychotherapeutic process instead of eliminating destructive attitudes.
Evaluation of uranium resources. Problems and constraints
International Nuclear Information System (INIS)
Williams, R.M.
1979-01-01
Growing awareness that the era of cheap energy is over has led to current efforts by governments and international organizations to examine the question of the adequacy of energy resources on a global scale. Despite the relative success of the NEA and the IAEA efforts in the study of world uranium supply, there is a need for such studies to become still more comprehensive and broader in scope. A basic problem exists with respect to the lack of a universally accepted set of resource terms by which to classify resource estimates once they are made. Often voids exist in international assessments because of insufficient data with respect to known resources and occasionally because of a lack of expertise to make the required estimates. With respect to the assessment of undiscovered uranium resources, major constraints are the relatively embryonic state of methodology for assessment of undiscovered resources and the fact that the inventory of basic geology, geochemical, and geophysical data is either incomplete or non-existent in many parts of the world. Finally, once resource estimates are made, there is often an unclear understanding about when and at what rate the resources can be made available. Hopefully, current efforts will lead to a solution to some of the principal problems and constraints which may be impeding progress toward an expansion and improvement of world uranium resource assessments. (author)
Eisenberg, C
2003-01-01
Market forces are continuously driving public and private organisations towards higher productivity, shorter process and production times, and fewer labour hours. To cope with these changes, organisations are adopting new organisational models of coordination and cooperation that increase their flexibility, consistency, efficiency, productivity and profit margins. In this thesis an organisational model of coordination and cooperation is examined using a real life example; the technical integration of a distributed large-scale project of an international physics collaboration. The distributed resource constraint project scheduling problem is modelled and solved with the methods of distributed constraint satisfaction. A distributed local search method, the distributed breakout algorithm (DisBO), is used as the basis for the coordination scheme. The efficiency of the local search method is improved by extending it with an incremental problem solving scheme with variable ordering. The scheme is implemented as cen...
On a Nonstationary Route Problem with Constraints
Directory of Open Access Journals (Sweden)
A. G. Chentsov
2012-01-01
Full Text Available The extremal route problem of permutations under constraints in the form of preceding conditions is investigated. It is supposed that an executer leaves the initial point (the base after which he visits a system of megalopolises (finite goal sets and performs some work on each megalopolis. The cost functions for executor permutations and interior works depend on the “visiting moment” that can correspond to the real time or can also correspond to the natural regular succession (the first visiting, the second visiting, and so on. An economic variant of the widely interpreted dynamic programming method (DPM is constructed. On this basis an optimal computer realized algorithm is constructed. A variant of a greed algorithm is proposed.
Analog Approach to Constraint Satisfaction Enabled by Spin Orbit Torque Magnetic Tunnel Junctions.
Wijesinghe, Parami; Liyanagedera, Chamika; Roy, Kaushik
2018-05-02
Boolean satisfiability (k-SAT) is an NP-complete (k ≥ 3) problem that constitute one of the hardest classes of constraint satisfaction problems. In this work, we provide a proof of concept hardware based analog k-SAT solver, that is built using Magnetic Tunnel Junctions (MTJs). The inherent physics of MTJs, enhanced by device level modifications, is harnessed here to emulate the intricate dynamics of an analog satisfiability (SAT) solver. In the presence of thermal noise, the MTJ based system can successfully solve Boolean satisfiability problems. Most importantly, our results exhibit that, the proposed MTJ based hardware SAT solver is capable of finding a solution to a significant fraction (at least 85%) of hard 3-SAT problems, within a time that has a polynomial relationship with the number of variables(<50).
Parallel constraint satisfaction in memory-based decisions.
Glöckner, Andreas; Hodges, Sara D
2011-01-01
Three studies sought to investigate decision strategies in memory-based decisions and to test the predictions of the parallel constraint satisfaction (PCS) model for decision making (Glöckner & Betsch, 2008). Time pressure was manipulated and the model was compared against simple heuristics (take the best and equal weight) and a weighted additive strategy. From PCS we predicted that fast intuitive decision making is based on compensatory information integration and that decision time increases and confidence decreases with increasing inconsistency in the decision task. In line with these predictions we observed a predominant usage of compensatory strategies under all time-pressure conditions and even with decision times as short as 1.7 s. For a substantial number of participants, choices and decision times were best explained by PCS, but there was also evidence for use of simple heuristics. The time-pressure manipulation did not significantly affect decision strategies. Overall, the results highlight intuitive, automatic processes in decision making and support the idea that human information-processing capabilities are less severely bounded than often assumed.
Logic-based methods for optimization combining optimization and constraint satisfaction
Hooker, John
2011-01-01
A pioneering look at the fundamental role of logic in optimization and constraint satisfaction While recent efforts to combine optimization and constraint satisfaction have received considerable attention, little has been said about using logic in optimization as the key to unifying the two fields. Logic-Based Methods for Optimization develops for the first time a comprehensive conceptual framework for integrating optimization and constraint satisfaction, then goes a step further and shows how extending logical inference to optimization allows for more powerful as well as flexible
Read, S J; Vanman, E J; Miller, L C
1997-01-01
We argue that recent work in connectionist modeling, in particular the parallel constraint satisfaction processes that are central to many of these models, has great importance for understanding issues of both historical and current concern for social psychologists. We first provide a brief description of connectionist modeling, with particular emphasis on parallel constraint satisfaction processes. Second, we examine the tremendous similarities between parallel constraint satisfaction processes and the Gestalt principles that were the foundation for much of modem social psychology. We propose that parallel constraint satisfaction processes provide a computational implementation of the principles of Gestalt psychology that were central to the work of such seminal social psychologists as Asch, Festinger, Heider, and Lewin. Third, we then describe how parallel constraint satisfaction processes have been applied to three areas that were key to the beginnings of modern social psychology and remain central today: impression formation and causal reasoning, cognitive consistency (balance and cognitive dissonance), and goal-directed behavior. We conclude by discussing implications of parallel constraint satisfaction principles for a number of broader issues in social psychology, such as the dynamics of social thought and the integration of social information within the narrow time frame of social interaction.
Life satisfaction and mental health problems (18 to 35 years).
Fergusson, D M; McLeod, G F H; Horwood, L J; Swain, N R; Chapple, S; Poulton, R
2015-08-01
Previous research has found that mental health is strongly associated with life satisfaction. In this study we examine associations between mental health problems and life satisfaction in a birth cohort studied from 18 to 35 years. Data were gathered during the Christchurch Health and Development Study, which is a longitudinal study of a birth cohort of 1265 children, born in Christchurch, New Zealand, in 1977. Assessments of psychiatric disorder (major depression, anxiety disorder, suicidality, alcohol dependence and illicit substance dependence) using DSM diagnostic criteria and life satisfaction were obtained at 18, 21, 25, 30 and 35 years. Significant associations (p life satisfaction and the psychiatric disorders major depression, anxiety disorder, suicidality, alcohol dependence and substance dependence. After adjustment for non-observed sources of confounding by fixed effects, statistically significant associations (p life satisfaction and major depression, anxiety disorder, suicidality and substance dependence. Overall, those reporting three or more mental health disorders had mean life satisfaction scores that were nearly 0.60 standard deviations below those without mental health problems. A structural equation model examined the direction of causation between life satisfaction and mental health problems. Statistically significant (p life satisfaction and mental health problems. After adjustment for confounding, robust and reciprocal associations were found between mental health problems and life satisfaction. Overall, this study showed evidence that life satisfaction influences mental disorder, and that mental disorder influences life satisfaction.
Principals' Self-Efficacy: Relations with Job Autonomy, Job Satisfaction, and Contextual Constraints
Federici, Roger A.
2013-01-01
The purpose of the present study was to explore relations between principals' self-efficacy, perceived job autonomy, job satisfaction, and perceived contextual constraints to autonomy. Principal self-efficacy was measured by a multidimensional scale called the Norwegian Principal Self-Efficacy Scale. Job autonomy, job satisfaction, and contextual…
About some types of constraints in problems of routing
Petunin, A. A.; Polishuk, E. G.; Chentsov, A. G.; Chentsov, P. A.; Ukolov, S. S.
2016-12-01
Many routing problems arising in different applications can be interpreted as a discrete optimization problem with additional constraints. The latter include generalized travelling salesman problem (GTSP), to which task of tool routing for CNC thermal cutting machines is sometimes reduced. Technological requirements bound to thermal fields distribution during cutting process are of great importance when developing algorithms for this task solution. These requirements give rise to some specific constraints for GTSP. This paper provides a mathematical formulation for the problem of thermal fields calculating during metal sheet thermal cutting. Corresponding algorithm with its programmatic implementation is considered. The mathematical model allowing taking such constraints into account considering other routing problems is discussed either.
L∞ Variational Problems with Running Costs and Constraints
International Nuclear Information System (INIS)
Aronsson, G.; Barron, E. N.
2012-01-01
Various approaches are used to derive the Aronsson–Euler equations for L ∞ calculus of variations problems with constraints. The problems considered involve holonomic, nonholonomic, isoperimetric, and isosupremic constraints on the minimizer. In addition, we derive the Aronsson–Euler equation for the basic L ∞ problem with a running cost and then consider properties of an absolute minimizer. Many open problems are introduced for further study.
Problems militating against job satisfaction among librarians in ...
African Journals Online (AJOL)
The research work examined the problems militating against job satisfaction among librarians in academic libraries in Niger State , Nigeria. The aim is to identify the problems associated with job satisfaction among librarians in academic libraries in Niger State. the population of the study was 58 librarians in Niger State.
Constraint Programming Approach to the Problem of Generating Milton Babbitt's All-partition Arrays
DEFF Research Database (Denmark)
Tanaka, Tsubasa; Bemman, Brian; Meredith, David
2016-01-01
elements and corresponding to a distinct integer partition of 12. Constraint programming (CP) is a tool for solving such combinatorial and constraint satisfaction problems. In this paper, we use CP for the first time to formalize this problem in generating an all-partition array. Solving the whole...... of this problem is difficult and few known solutions exist. Therefore, we propose solving two sub-problems and joining these to form a complete solution. We conclude by presenting a solution found using this method. Our solution is the first we are aware of to be discovered automatically using a computer......Milton Babbitt (1916–2011) was a composer of twelve-tone serial music noted for creating the all-partition array. One part of the problem in generating an all-partition array requires finding a covering of a pitch-class matrix by a collection of sets, each forming a region containing 12 distinct...
Iterative Schemes for Convex Minimization Problems with Constraints
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2014-01-01
Full Text Available We first introduce and analyze one implicit iterative algorithm for finding a solution of the minimization problem for a convex and continuously Fréchet differentiable functional, with constraints of several problems: the generalized mixed equilibrium problem, the system of generalized equilibrium problems, and finitely many variational inclusions in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another implicit iterative algorithm for finding a fixed point of infinitely many nonexpansive mappings with the same constraints, and derive its strong convergence under mild assumptions.
Constraint Optimization for Highly Constrained Logistic Problems
DEFF Research Database (Denmark)
Mochnacs, Maria Kinga; Tanaka, Meang Akira; Nyborg, Anders
This report investigates whether propagators combined with branch and bound algorithm are suitable for solving the storage area stowage problem within reasonable time. The approach has not been attempted before and experiments show that the implementation was not capable of solving the storage ar...
Constraint-Based Local Search for Constrained Optimum Paths Problems
Pham, Quang Dung; Deville, Yves; van Hentenryck, Pascal
Constrained Optimum Path (COP) problems arise in many real-life applications and are ubiquitous in communication networks. They have been traditionally approached by dedicated algorithms, which are often hard to extend with side constraints and to apply widely. This paper proposes a constraint-based local search (CBLS) framework for COP applications, bringing the compositionality, reuse, and extensibility at the core of CBLS and CP systems. The modeling contribution is the ability to express compositional models for various COP applications at a high level of abstraction, while cleanly separating the model and the search procedure. The main technical contribution is a connected neighborhood based on rooted spanning trees to find high-quality solutions to COP problems. The framework, implemented in COMET, is applied to Resource Constrained Shortest Path (RCSP) problems (with and without side constraints) and to the edge-disjoint paths problem (EDP). Computational results show the potential significance of the approach.
Monroe, Brian M.; Read, Stephen J.
2008-01-01
A localist, parallel constraint satisfaction, artificial neural network model is presented that accounts for a broad collection of attitude and attitude-change phenomena. The network represents the attitude object and cognitions and beliefs related to the attitude, as well as how to integrate a persuasive message into this network. Short-term…
Stochastic programming problems with generalized integrated chance constraints
Czech Academy of Sciences Publication Activity Database
Branda, Martin
2012-01-01
Roč. 61, č. 8 (2012), s. 949-968 ISSN 0233-1934 R&D Projects: GA ČR GAP402/10/1610 Grant - others:SVV(CZ) 261315/2010 Institutional support: RVO:67985556 Keywords : chance constraints * integrated chance constraints * penalty functions * sample approximations * blending problem Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.707, year: 2012 http://library.utia.cas.cz/separaty/2012/E/branda-stochastic programming problems with generalized integrated.pdf
Multi-dimensional Bin Packing Problems with Guillotine Constraints
DEFF Research Database (Denmark)
Amossen, Rasmus Resen; Pisinger, David
2010-01-01
The problem addressed in this paper is the decision problem of determining if a set of multi-dimensional rectangular boxes can be orthogonally packed into a rectangular bin while satisfying the requirement that the packing should be guillotine cuttable. That is, there should exist a series of face...... parallel straight cuts that can recursively cut the bin into pieces so that each piece contains a box and no box has been intersected by a cut. The unrestricted problem is known to be NP-hard. In this paper we present a generalization of a constructive algorithm for the multi-dimensional bin packing...... problem, with and without the guillotine constraint, based on constraint programming....
The Effect of Some Constraints on Mathematics Instructors' Problem ...
African Journals Online (AJOL)
This study was designed to examine the effect of perceived constraints on four universities mathematics department instructors' classroom practices of problem solving in teaching mathematics. To this end, the target population of the study includes mathematics instructors in the Amhara Regional state universities. From a ...
Introducing radiality constraints in capacitated location-routing problems
Directory of Open Access Journals (Sweden)
Eliana Mirledy Toro Ocampo
2017-03-01
Full Text Available In this paper, we introduce a unified mathematical formulation for the Capacitated Vehicle Routing Problem (CVRP and for the Capacitated Location Routing Problem (CLRP, adopting radiality constraints in order to guarantee valid routes and eliminate subtours. This idea is inspired by formulations already employed in electric power distribution networks, which requires a radial topology in its operation. The results show that the proposed formulation greatly improves the convergence of the solver.
Computing group cardinality constraint solutions for logistic regression problems.
Zhang, Yong; Kwon, Dongjin; Pohl, Kilian M
2017-01-01
We derive an algorithm to directly solve logistic regression based on cardinality constraint, group sparsity and use it to classify intra-subject MRI sequences (e.g. cine MRIs) of healthy from diseased subjects. Group cardinality constraint models are often applied to medical images in order to avoid overfitting of the classifier to the training data. Solutions within these models are generally determined by relaxing the cardinality constraint to a weighted feature selection scheme. However, these solutions relate to the original sparse problem only under specific assumptions, which generally do not hold for medical image applications. In addition, inferring clinical meaning from features weighted by a classifier is an ongoing topic of discussion. Avoiding weighing features, we propose to directly solve the group cardinality constraint logistic regression problem by generalizing the Penalty Decomposition method. To do so, we assume that an intra-subject series of images represents repeated samples of the same disease patterns. We model this assumption by combining series of measurements created by a feature across time into a single group. Our algorithm then derives a solution within that model by decoupling the minimization of the logistic regression function from enforcing the group sparsity constraint. The minimum to the smooth and convex logistic regression problem is determined via gradient descent while we derive a closed form solution for finding a sparse approximation of that minimum. We apply our method to cine MRI of 38 healthy controls and 44 adult patients that received reconstructive surgery of Tetralogy of Fallot (TOF) during infancy. Our method correctly identifies regions impacted by TOF and generally obtains statistically significant higher classification accuracy than alternative solutions to this model, i.e., ones relaxing group cardinality constraints. Copyright © 2016 Elsevier B.V. All rights reserved.
Learning and Parallelization Boost Constraint Search
Yun, Xi
2013-01-01
Constraint satisfaction problems are a powerful way to abstract and represent academic and real-world problems from both artificial intelligence and operations research. A constraint satisfaction problem is typically addressed by a sequential constraint solver running on a single processor. Rather than construct a new, parallel solver, this work…
Interactive activation and mutual constraint satisfaction in perception and cognition.
McClelland, James L; Mirman, Daniel; Bolger, Donald J; Khaitan, Pranav
2014-08-01
In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis-the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive activation model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that
Bin-packing problems with load balancing and stability constraints
DEFF Research Database (Denmark)
Trivella, Alessio; Pisinger, David
apper in a wide range of disciplines, including transportation and logistics, computer science, engineering, economics and manufacturing. The problem is well-known to be N P-hard and difficult to solve in practice, especially when dealing with the multi-dimensional cases. Closely connected to the BPP...... realistic constraints related to e.g. load balancing, cargo stability and weight limits, in the multi-dimensional BPP. The BPP poses additional challenges compared to the CLP due to the supplementary objective of minimizing the number of bins. In particular, in section 2 we discuss how to integrate bin......-packing and load balancing of items. The problem has only been considered in the literature in simplified versions, e.g. balancing a single bin or introducing a feasible region for the barycenter. In section 3 we generalize the problem to handle cargo stability and weight constraints....
Quadratic third-order tensor optimization problem with quadratic constraints
Directory of Open Access Journals (Sweden)
Lixing Yang
2014-05-01
Full Text Available Quadratically constrained quadratic programs (QQPs problems play an important modeling role for many diverse problems. These problems are in general NP hard and numerically intractable. Semidenite programming (SDP relaxations often provide good approximate solutions to these hard problems. For several special cases of QQP, e.g., convex programs and trust region subproblems, SDP relaxation provides the exact optimal value, i.e., there is a zero duality gap. However, this is not true for the general QQP, or even the QQP with two convex constraints, but a nonconvex objective.In this paper, we consider a certain QQP where the variable is neither vector nor matrix but a third-order tensor. This problem can be viewed as a generalization of the ordinary QQP with vector or matrix as it's variant. Under some mild conditions, we rst show that SDP relaxation provides exact optimal solutions for the original problem. Then we focus on two classes of homogeneous quadratic tensor programming problems which have no requirements on the constraints number. For one, we provide an easily implemental polynomial time algorithm to approximately solve the problem and discuss the approximation ratio. For the other, we show there is no gap between the SDP relaxation and itself.
1-Skeletons of the Spanning Tree Problems with Additional Constraints
Directory of Open Access Journals (Sweden)
V. A. Bondarenko
2015-01-01
Full Text Available In this paper, we study polyhedral properties of two spanning tree problems with additional constraints. In the first problem, it is required to find a tree with a minimum sum of edge weights among all spanning trees with the number of leaves less than or equal to a given value. In the second problem, an additional constraint is the assumption that the degree of all nodes of the spanning tree does not exceed a given value. The recognition versions of both problems are NP-complete. We consider polytopes of these problems and their 1-skeletons. We prove that in both cases it is a NP-complete problem to determine whether the vertices of 1-skeleton are adjacent. Although it is possible to obtain a superpolynomial lower bounds on the clique numbers of these graphs. These values characterize the time complexity in a broad class of algorithms based on linear comparisons. The results indicate a fundamental difference between combinatorial and geometric properties of the considered problems from the classical minimum spanning tree problem.
The Approximability of Learning and Constraint Satisfaction Problems
2010-10-07
further improved this result to NP ⊆ naPCP1,3/4+²(O(log(n)),3). Around the same time, Zwick [141] showed that naPCP1,5/8(O(log(n)),3)⊆ BPP by giving a...randomized polynomial-time 5/8-approximation algorithm for satisfiable 3CSP. Therefore unless NP⊆ BPP , the best s must be bigger than 5/8. Zwick... BPP [141]. We think that Question 5.1.2 addresses an important missing part in understanding the 3-query PCP systems. In addition, as is mentioned the
Optimal consumption—portfolio problem with CVaR constraints
International Nuclear Information System (INIS)
Zhang, Qingye; Gao, Yan
2016-01-01
The optimal portfolio selection is a fundamental issue in finance, and its two most important ingredients are risk and return. Merton's pioneering work in dynamic portfolio selection emphasized only the expected utility of the consumption and the terminal wealth. To make the optimal portfolio strategy be achievable, risk control over bankruptcy during the investment horizon is an indispensable ingredient. So, in this paper, we consider the consumption-portfolio problem coupled with a dynamic risk control. More specifically, different from the existing literature, we impose a dynamic relative CVaR constraint on it. By the stochastic dynamic programming techniques, we derive the corresponding Hamilton–Jacobi–Bellman (HJB) equation. Moreover, by the Lagrange multiplier method, the closed form solution is provided when the utility function is a logarithmic one. At last, an illustrative empirical study is given. The results show the distinct difference of the portfolio strategies with and without the CVaR constraints: the proportion invested in the risky assets is reduced over time with CVaR constraint instead of being constant without CVaR constraints. This can provide a good decision-making reference for the investors.
Topology optimization problems with design-dependent sets of constraints
DEFF Research Database (Denmark)
Schou, Marie-Louise Højlund
Topology optimization is a design tool which is used in numerous fields. It can be used whenever the design is driven by weight and strength considerations. The basic concept of topology optimization is the interpretation of partial differential equation coefficients as effective material...... properties and designing through changing these coefficients. For example, consider a continuous structure. Then the basic concept is to represent this structure by small pieces of material that are coinciding with the elements of a finite element model of the structure. This thesis treats stress constrained...... structural topology optimization problems. For such problems a stress constraint for an element should only be present in the optimization problem when the structural design variable corresponding to this element has a value greater than zero. We model the stress constrained topology optimization problem...
Quantization of (2 + 1)-spinning particles and bifermionic constraint problem
Energy Technology Data Exchange (ETDEWEB)
Fresneda, R [Instituto de FIsica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, SP (Brazil); Gavrilov, S P [Instituto de FIsica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, SP (Brazil); Gitman, D M [Instituto de FIsica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, SP (Brazil); Moshin, P Yu [Instituto de FIsica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, SP (Brazil)
2004-03-21
This work is a natural continuation of our recent study in quantizing relativistic particles. There it was demonstrated that, by applying a consistent quantization scheme to the classical model of a spinless relativistic particle as well as to the Berezin-Marinov model of a 3 + 1 Dirac particle, it is possible to obtain a consistent relativistic quantum mechanics of such particles. In the present paper, we apply a similar approach to the problem of quantizing the massive 2 + 1 Dirac particle. However, we stress that such a problem differs in a nontrivial way from the one in 3 + 1 dimensions. The point is that in 2 + 1 dimensions each spin polarization describes different fermion species. Technically this fact manifests itself through the presence of a bifermionic constant and of a bifermionic first-class constraint. In particular, this constraint does not admit a conjugate gauge condition at the classical level. The quantization problem in 2 + 1 dimensions is also interesting from the physical viewpoint (e.g., anyons). In order to quantize the model, we first derive a classical formulation in an effective phase space, restricted by constraints and gauges. Then the condition of preservation of the classical symmetries allows us to realize the operator algebra in an unambiguous way and construct an appropriate Hilbert space. The physical sector of the constructed quantum mechanics contains spin-1/2 particles and antiparticles without an infinite number of negative-energy levels, and exactly reproduces the one-particle sector of the 2 + 1 quantum theory of a spinor field.
What is adaptive about adaptive decision making? A parallel constraint satisfaction account.
Glöckner, Andreas; Hilbig, Benjamin E; Jekel, Marc
2014-12-01
There is broad consensus that human cognition is adaptive. However, the vital question of how exactly this adaptivity is achieved has remained largely open. Herein, we contrast two frameworks which account for adaptive decision making, namely broad and general single-mechanism accounts vs. multi-strategy accounts. We propose and fully specify a single-mechanism model for decision making based on parallel constraint satisfaction processes (PCS-DM) and contrast it theoretically and empirically against a multi-strategy account. To achieve sufficiently sensitive tests, we rely on a multiple-measure methodology including choice, reaction time, and confidence data as well as eye-tracking. Results show that manipulating the environmental structure produces clear adaptive shifts in choice patterns - as both frameworks would predict. However, results on the process level (reaction time, confidence), in information acquisition (eye-tracking), and from cross-predicting choice consistently corroborate single-mechanisms accounts in general, and the proposed parallel constraint satisfaction model for decision making in particular. Copyright © 2014 Elsevier B.V. All rights reserved.
A green vehicle routing problem with customer satisfaction criteria
Afshar-Bakeshloo, M.; Mehrabi, A.; Safari, H.; Maleki, M.; Jolai, F.
2016-12-01
This paper develops an MILP model, named Satisfactory-Green Vehicle Routing Problem. It consists of routing a heterogeneous fleet of vehicles in order to serve a set of customers within predefined time windows. In this model in addition to the traditional objective of the VRP, both the pollution and customers' satisfaction have been taken into account. Meanwhile, the introduced model prepares an effective dashboard for decision-makers that determines appropriate routes, the best mixed fleet, speed and idle time of vehicles. Additionally, some new factors evaluate the greening of each decision based on three criteria. This model applies piecewise linear functions (PLFs) to linearize a nonlinear fuzzy interval for incorporating customers' satisfaction into other linear objectives. We have presented a mixed integer linear programming formulation for the S-GVRP. This model enriches managerial insights by providing trade-offs between customers' satisfaction, total costs and emission levels. Finally, we have provided a numerical study for showing the applicability of the model.
Shinzato, Takashi
2017-02-01
In the present paper, the minimal investment risk for a portfolio optimization problem with imposed budget and investment concentration constraints is considered using replica analysis. Since the minimal investment risk is influenced by the investment concentration constraint (as well as the budget constraint), it is intuitive that the minimal investment risk for the problem with an investment concentration constraint can be larger than that without the constraint (that is, with only the budget constraint). Moreover, a numerical experiment shows the effectiveness of our proposed analysis. In contrast, the standard operations research approach failed to identify accurately the minimal investment risk of the portfolio optimization problem.
Dynamics of relativistic point particles as a problem with constraints
International Nuclear Information System (INIS)
Todorov, I.T.
1976-01-01
The relativistic n-particle dynamics is studied as a problem with constraints of the type (2phisub(i)=)msub(i)sup(2)-psub(i)sup(2)+PHIsub(i)=0, i=1,...,n, (C) where PHIsub(i) are Poincare invariant functions of the particles' coordinates, momenta and spin components; PHIsib(i) is assumed to vanish asymptotically when the i-th particle coordinates tend to infinity. In the two particle case it is assumed in addition that the Poisson bracket [phi 1 , phi 2 ] vanishes on the surface (C). That allows us to give a formulation of the theory, invariant with respect to the choice of the time-parameter on each trajectory. The quantization of the relative two-particle motion is also discussed. It is pointed out that the stationary Schrodinger equation obtained in this manner is a local quasipotential equation
Producing Satisfactory Solutions to Scheduling Problems: An Iterative Constraint Relaxation Approach
Chien, S.; Gratch, J.
1994-01-01
One drawback to using constraint-propagation in planning and scheduling systems is that when a problem has an unsatisfiable set of constraints such algorithms typically only show that no solution exists. While, technically correct, in practical situations, it is desirable in these cases to produce a satisficing solution that satisfies the most important constraints (typically defined in terms of maximizing a utility function). This paper describes an iterative constraint relaxation approach in which the scheduler uses heuristics to progressively relax problem constraints until the problem becomes satisfiable. We present empirical results of applying these techniques to the problem of scheduling spacecraft communications for JPL/NASA antenna resources.
Iwasaki, Hirotoshi; Sega, Shinichiro; Hiraishi, Hironori; Mizoguchi, Fumio
In recent years, lots of music content can be stored in mobile computing devices, such as a portable digital music player and a car navigation system. Moreover, various information content like news or traffic information can be acquired always anywhere by a cellular communication and a wireless LAN. However, usability issues arise from the simple interfaces of mobile computing devices. Moreover, retrieving and selecting such content poses safety issues, especially while driving. Thus, it is important for the mobile system to recommend content automatically adapted to user's preference and situation. In this paper, we present the user-adapted program scheduling that generates sequences of content (Program) suiting user's preference and situation based on the Bayesian network and the Constraint Satisfaction Problem (CSP) technique. We also describe the design and evaluation of its realization system, the Personal Program Producer (P3). First, preference such as a genre ratio of content in a program is learned as a Bayesian network model using simple operations such as a skip behavior. A model including each content tends to become large-scale. In order to make it small, we present the model separation method that carries out losslessly compression of the model. Using the model, probabilistic distributions of preference to generate constraints are inferred. Finally satisfying the constraints, a program is produced. This kind of CSP has an issue of which the number of variables is not fixedness. In order to make it variable, we propose a method using metavariables. To evaluate the above methods, we applied them to P3 on a car navigation system. User evaluations helped us clarify that the P3 can produce the program that a user prefers and adapt it to the user.
Bidirectional Associations Between Newlyweds' Marital Satisfaction and Marital Problems over Time.
Lavner, Justin A; Karney, Benjamin R; Williamson, Hannah C; Bradbury, Thomas N
2017-12-01
Prevailing views of marital functioning generally adopt the view that marital problems predict decreases in marital satisfaction, but alternative theoretical perspectives raise the possibility that lowered satisfaction can also predict increases in problems. The current study sought to integrate and compare these perspectives by examining the bidirectional cross-lagged associations between newlyweds' reports of their marital satisfaction and marital problems over the first 4 years of marriage. Using annual assessments from 483 heterosexual newlywed couples, we find evidence for problem-to-satisfaction linkages as well as satisfaction-to-problem linkages. Satisfaction was a stronger predictor of marital problems early in marriage but not as time passed; by Year 4 only problem-to-satisfaction linkages remained significant. These findings are consistent with the idea that couples with more problems go on to report lower levels of satisfaction and couples with lower levels of satisfaction go on to report more marital problems. This dynamic interplay between global judgments about relationship satisfaction and ongoing specific relationship difficulties highlights the value of examining bidirectional effects to better understand marital functioning over time. © 2016 Family Process Institute.
Production constraints and perceived marketing problems of stock ...
African Journals Online (AJOL)
In an endeavour to improve the livestock production and particularly the marketing of livestock in the Northern Communal Areas of Namibia, this study analyses the perception of livestock farmers in this regard. The low off-take percentage is the most serious production constraint, but marketing, although a constraint, is not ...
Czech Academy of Sciences Publication Activity Database
Červinka, Michal; Kanzow, Ch.; Schwartz, A.
2016-01-01
Roč. 160, č. 1 (2016), s. 353-377 ISSN 0025-5610 R&D Projects: GA ČR GAP402/12/1309; GA ČR GA15-00735S Institutional support: RVO:67985556 Keywords : Cardinality constraints * Constraint qualifications * Optimality conditions * KKT conditions * Strongly stationary points Subject RIV: BA - General Mathematics Impact factor: 2.446, year: 2016 http://library.utia.cas.cz/separaty/2016/MTR/cervinka-0461165.pdf
Feed Forward Neural Network and Optimal Control Problem with Control and State Constraints
Kmet', Tibor; Kmet'ová, Mária
2009-09-01
A feed forward neural network based optimal control synthesis is presented for solving optimal control problems with control and state constraints. The paper extends adaptive critic neural network architecture proposed by [5] to the optimal control problems with control and state constraints. The optimal control problem is transcribed into a nonlinear programming problem which is implemented with adaptive critic neural network. The proposed simulation method is illustrated by the optimal control problem of nitrogen transformation cycle model. Results show that adaptive critic based systematic approach holds promise for obtaining the optimal control with control and state constraints.
Robinson, Merideth; Neece, Cameron L.
2015-01-01
Studies have found that low marital satisfaction, parenting stress, and child behavior problems are linked in families of children with developmental delays (DD). However, previous investigations examining the relationships between parenting stress, child behavior problems, and marital satisfaction rarely examine the interrelationships of these…
L{sup {infinity}} Variational Problems with Running Costs and Constraints
Energy Technology Data Exchange (ETDEWEB)
Aronsson, G., E-mail: gunnar.aronsson@liu.se [Linkoeping University, Department of Mathematics (Sweden); Barron, E. N., E-mail: enbarron@math.luc.edu [Loyola University of Chicago, Department of Mathematics and Statistics (United States)
2012-02-15
Various approaches are used to derive the Aronsson-Euler equations for L{sup {infinity}} calculus of variations problems with constraints. The problems considered involve holonomic, nonholonomic, isoperimetric, and isosupremic constraints on the minimizer. In addition, we derive the Aronsson-Euler equation for the basic L{sup {infinity}} problem with a running cost and then consider properties of an absolute minimizer. Many open problems are introduced for further study.
Ant colony optimization and constraint programming
Solnon, Christine
2013-01-01
Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search
Quantization of 2 + 1-spinning particles and bifermionic constraint problem
Energy Technology Data Exchange (ETDEWEB)
Fresneda, R.; Gavrilov, S.P.; Gitman, D.M.; Moshin, P.Yu. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica
2004-07-01
In this paper, we have quantized a P- and T-noninvariant pseudoclassical model of a massive relativistic spin-1=2 particle in 2 + 1 dimensions, on the background of an arbitrary U(1) gauge vector field. A peculiar feature of the model at the classical level is that it contains a bifermionic first-class constraint, which does not admit gauge-fixing. It is shown that this first-class constraint can be realized at the quantum level as a bounded operator, which is imposed as a condition on the state vectors (by analogy with the Dirac quantization method). This allows us to generalize the quantization scheme [?] in case there is a bifermionic first-class constraint.We present a detailed construction of the Hilbert space and verify that the constructed QM possesses the necessary symmetry properties. We show that the condition of preservation of the classical symmetries under the restricted Lorentz transformations and the U(1) transformations allows one to realize the operator algebra in an unambiguous way. Within the constructed relativistic QM, we select a physical subspace which describes the one-particle sector. The physical sector of the QM contains both particles and antiparticles with positive energy hat {omega} levels, and exactly reproduces the one-particle sector of the quantum theory of the 2 + 1 spinor field. (author)
International Nuclear Information System (INIS)
Harding, P.J.
2017-01-01
In the wake of the decommissioning of numerous nuclear power plants in Germany, techniques to reduce the number of costly waste casks or containers are sought after. The large bandwidth of limits (dose rate, mass, individual nuclide activities, chemical composition...) the waste packages have to comply with for both interim storage facilities and the repository Konrad render the manual planning of packaging concepts prohibitive. However, in the past, the planning for packaging has been performed in this way, albeit on the basis of several facilitating assumptions. Surprisingly, to the best of our knowledge, the automated computer-assisted generation of packaging plans for radioactive waste has not been demonstrated previously. In this talk we demonstrate how the conditioning and packing of 160 control rod assemblies was optimised using constraint satisfaction algorithms. These algorithms can be executed by a computer in a few minutes, thus considerably accelerating the generation of packaging plans, while optimising the utilisation of the waste casks and containers with respect to mass, activity, dose rate, etc. This automated and computer-assisted procedure took into account complex logistical boundary conditions present during decommissioning, such as space requirements, the sequence of the waste and the (lack of) availability of suitable waste casks. In addition, packaging concepts based on several scenarios (cask availability, space requirements,...) were easily and automatically generated once the packaging rules had been coded. We demonstrate the successful application of these algorithms to a real packaging campaign of control rod assemblies of a boiling water reactor, for which excellent results were achieved. We also present an outlook of a much larger scale project, in which the logistics and storage of radioactive waste packages is mathematically optimised. Finally, we give prospects on these techniques to others, similar logistical problems currently
Bruhn, Peter; Geyer-Schulz, Andreas
2002-01-01
In this paper, we introduce genetic programming over context-free languages with linear constraints for combinatorial optimization, apply this method to several variants of the multidimensional knapsack problem, and discuss its performance relative to Michalewicz's genetic algorithm with penalty functions. With respect to Michalewicz's approach, we demonstrate that genetic programming over context-free languages with linear constraints improves convergence. A final result is that genetic programming over context-free languages with linear constraints is ideally suited to modeling complementarities between items in a knapsack problem: The more complementarities in the problem, the stronger the performance in comparison to its competitors.
Life Satisfaction among High School Students with Social, Emotional, and Behavioral Problems
State, Talida M.; Kern, Lee
2017-01-01
Over the last decade, there has been increased interest in measuring life satisfaction among children and adolescents as an indicator of broad well-being and happiness. Although limited, existing research with students with social, emotional, and behavioral (SEB) problems indicates they experience lower life satisfaction compared with their…
Anicic, Katarina Pažur; Mekovec, Renata
2016-01-01
This paper describes the implementation of problem-based learning (PBL) principles in an undergraduate IT service management course, followed by the results about student satisfaction and work performance. The results indicate the students' general satisfaction with the course implementation, as well as some challenges regarding the…
Vannier, Sarah A; Rosen, Natalie O
2017-03-01
Sexual problems are common during pregnancy, but the proportion of pregnant women who experience sexual distress is unknown. In non-pregnant samples, sexual distress is associated with lower sexual and relationship satisfaction. To identify the proportion of women experiencing sexual distress during pregnancy and to compare the sexual and relationship satisfaction of women who report sexual distress during pregnancy with that of women without distress. Two-hundred sixty-one pregnant women completed a cross-sectional online survey. Women completed validated measurements of sexual functioning (Female Sexual Function Index; score sexual problem), sexual distress (Female Sexual Distress Scale; score ≥ 15 indicates clinically significant distress), sexual satisfaction (Global Measure of Sexual Satisfaction), and relationship satisfaction (Couples Satisfaction Index). Overall, 42% of women met the clinical cutoff for sexual distress. Of sexually active women (n = 230), 26% reported concurrent sexual problems and distress and 14% reported sexual distress in the absence of sexual problems. Sexual distress and/or problems in sexual functioning were linked to lower sexual and relationship satisfaction compared with pregnant women with lower sexual distress and fewer sexual problems. Sexual distress is common during pregnancy and associated with lower sexual and relationship satisfaction. Health care providers should ask pregnant women about feelings of sexual distress. Identifying pregnant women who experience sexual distress and referring them to appropriate resources could help minimize sexual and relationship problems during pregnancy. Vannier SA, Rosen NO. Sexual Distress and Sexual Problems During Pregnancy: Associations With Sexual and Relationship Satisfaction. J Sex Med 2017;14:387-395. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.
van der Voordt, Theo; Brunia, Sandra; Appel - Meulenbroek, Rianne; Jensen, P.A.; van der Voordt, T.
2016-01-01
This chapter presents some findings from surveys on employee satisfaction in different work environments in the Netherlands and various other European countries. It first discusses why employee satisfaction is relevant for organisations and which factors may influence employee satisfaction. Then the
Directory of Open Access Journals (Sweden)
Paweł Sitek
2016-01-01
Full Text Available This paper presents a hybrid method for modeling and solving supply chain optimization problems with soft, hard, and logical constraints. Ability to implement soft and logical constraints is a very important functionality for supply chain optimization models. Such constraints are particularly useful for modeling problems resulting from commercial agreements, contracts, competition, technology, safety, and environmental conditions. Two programming and solving environments, mathematical programming (MP and constraint logic programming (CLP, were combined in the hybrid method. This integration, hybridization, and the adequate multidimensional transformation of the problem (as a presolving method helped to substantially reduce the search space of combinatorial models for supply chain optimization problems. The operation research MP and declarative CLP, where constraints are modeled in different ways and different solving procedures are implemented, were linked together to use the strengths of both. This approach is particularly important for the decision and combinatorial optimization models with the objective function and constraints, there are many decision variables, and these are summed (common in manufacturing, supply chain management, project management, and logistic problems. The ECLiPSe system with Eplex library was proposed to implement a hybrid method. Additionally, the proposed hybrid transformed model is compared with the MILP-Mixed Integer Linear Programming model on the same data instances. For illustrative models, its use allowed finding optimal solutions eight to one hundred times faster and reducing the size of the combinatorial problem to a significant extent.
Strategies for refinancing of SMEs in Bangladesh: Problems & constraints
Directory of Open Access Journals (Sweden)
Amitav Saha
2011-12-01
Full Text Available Over the past decade, there has been a significant change in the world trade regime, too. The WTO techniques agreements limit the use of certain trade measures as quantitative restrictions and subsidies. Such development has also implication for a country's strategy in supporting its domestic industry in including SMEs. WTO agreements cover not only the traditional goods sector but also new sectors like services and intellectual property rights. There is a tendency for considering these newly included sectors as constraints to trade prospects of a poor country like Bangladesh. There are certain other areas where improvements provide genuine incentives to SMEs and contribute to their enhanced competitiveness. Improved infrastructure, better law and order situation, and efficient ports and transportation are likely to impact favorably upon the SMEs sector and such things may be no less important than mere policy supported incentives. However, these provisions have now become realities. Bangladesh should continue its efforts to make the world community appreciate the difficult economic situation of the LDCs and to help to attain various trade preferences and concessions. Its long-run economic prosperity critically depends on success or otherwise of its efforts to turn the challenges of globalization opportunities. This will create a strong and potential base for economic development, which will in turn accelerate the process of poverty reduction, and reduction of unemployment, create employment opportunities as well as accelerate the overall economic growth of the country.
Optimization problems with equilibrium constraints and their numerical solution
Czech Academy of Sciences Publication Activity Database
Kočvara, Michal; Outrata, Jiří
Roč. 101 , č. 1 (2004), s. 119-149 ISSN 0025-5610 R&D Projects: GA AV ČR IAA1075005 Grant - others:BMBF(DE) 03ZOM3ER Institutional research plan: CEZ:AV0Z1075907 Keywords : optimization problems * MPEC * MPCC Subject RIV: BA - General Mathematics Impact factor: 1.016, year: 2004
Directory of Open Access Journals (Sweden)
J. Fabian Lopez
2010-01-01
Full Text Available We consider a Pickup and Delivery Vehicle Routing Problem (PDP commonly encountered in real-world logistics operations. The problem involves a set of practical complications that have received little attention in the vehicle routing literature. In this problem, there are multiple vehicle types available to cover a set of pickup and delivery requests, each of which has pickup time windows and delivery time windows. Transportation orders and vehicle types must satisfy a set of compatibility constraints that specify which orders cannot be covered by which vehicle types. In addition we include some dock service capacity constraints as is required on common real world operations. This problem requires to be attended on large scale instances (orders ≥ 500, (vehicles ≥ 150. As a generalization of the traveling salesman problem, clearly this problem is NP-hard. The exact algorithms are too slow for large scale instances. The PDP-TWDS is both a packing problem (assign order to vehicles, and a routing problem (find the best route for each vehicle. We propose to solve the problem in three stages. The first stage constructs initials solutions at aggregate level relaxing some constraints on the original problem. The other two stages imposes time windows and dock service constraints. Our results are favorable finding good quality solutions in relatively short computational times.
Orr, Mark G; Thrush, Roxanne; Plaut, David C
2013-01-01
The reasoned action approach, although ubiquitous in health behavior theory (e.g., Theory of Reasoned Action/Planned Behavior), does not adequately address two key dynamical aspects of health behavior: learning and the effect of immediate social context (i.e., social influence). To remedy this, we put forth a computational implementation of the Theory of Reasoned Action (TRA) using artificial-neural networks. Our model re-conceptualized behavioral intention as arising from a dynamic constraint satisfaction mechanism among a set of beliefs. In two simulations, we show that constraint satisfaction can simultaneously incorporate the effects of past experience (via learning) with the effects of immediate social context to yield behavioral intention, i.e., intention is dynamically constructed from both an individual's pre-existing belief structure and the beliefs of others in the individual's social context. In a third simulation, we illustrate the predictive ability of the model with respect to empirically derived behavioral intention. As the first known computational model of health behavior, it represents a significant advance in theory towards understanding the dynamics of health behavior. Furthermore, our approach may inform the development of population-level agent-based models of health behavior that aim to incorporate psychological theory into models of population dynamics.
Directory of Open Access Journals (Sweden)
Mark G Orr
Full Text Available The reasoned action approach, although ubiquitous in health behavior theory (e.g., Theory of Reasoned Action/Planned Behavior, does not adequately address two key dynamical aspects of health behavior: learning and the effect of immediate social context (i.e., social influence. To remedy this, we put forth a computational implementation of the Theory of Reasoned Action (TRA using artificial-neural networks. Our model re-conceptualized behavioral intention as arising from a dynamic constraint satisfaction mechanism among a set of beliefs. In two simulations, we show that constraint satisfaction can simultaneously incorporate the effects of past experience (via learning with the effects of immediate social context to yield behavioral intention, i.e., intention is dynamically constructed from both an individual's pre-existing belief structure and the beliefs of others in the individual's social context. In a third simulation, we illustrate the predictive ability of the model with respect to empirically derived behavioral intention. As the first known computational model of health behavior, it represents a significant advance in theory towards understanding the dynamics of health behavior. Furthermore, our approach may inform the development of population-level agent-based models of health behavior that aim to incorporate psychological theory into models of population dynamics.
Marco A. Contreras; Woodam Chung; Greg Jones
2008-01-01
Forest transportation planning problems (FTPP) have evolved from considering only the financial aspects of timber management to more holistic problems that also consider the environmental impacts of roads. These additional requirements have introduced side constraints, making FTPP larger and more complex. Mixed-integer programming (MIP) has been used to solve FTPP, but...
Directory of Open Access Journals (Sweden)
Nebojsa Bacanin
2014-01-01
portfolio model with entropy constraint. Firefly algorithm is one of the latest, very successful swarm intelligence algorithm; however, it exhibits some deficiencies when applied to constrained problems. To overcome lack of exploration power during early iterations, we modified the algorithm and tested it on standard portfolio benchmark data sets used in the literature. Our proposed modified firefly algorithm proved to be better than other state-of-the-art algorithms, while introduction of entropy diversity constraint further improved results.
New Boundary Constraints for Elliptic Systems used in Grid Generation Problems
Kaul, Upender K.; Clancy, Daniel (Technical Monitor)
2002-01-01
This paper discusses new boundary constraints for elliptic partial differential equations as used in grid generation problems in generalized curvilinear coordinate systems. These constraints, based on the principle of local conservation of thermal energy in the vicinity of the boundaries, are derived using the Green's Theorem. They uniquely determine the so called decay parameters in the source terms of these elliptic systems. These constraints' are designed for boundary clustered grids where large gradients in physical quantities need to be resolved adequately. It is observed that the present formulation also works satisfactorily for mild clustering. Therefore, a closure for the decay parameter specification for elliptic grid generation problems has been provided resulting in a fully automated elliptic grid generation technique. Thus, there is no need for a parametric study of these decay parameters since the new constraints fix them uniquely. It is also shown that for Neumann type boundary conditions, these boundary constraints uniquely determine the solution to the internal elliptic problem thus eliminating the non-uniqueness of the solution of an internal Neumann boundary value grid generation problem.
2014-01-01
Portfolio optimization (selection) problem is an important and hard optimization problem that, with the addition of necessary realistic constraints, becomes computationally intractable. Nature-inspired metaheuristics are appropriate for solving such problems; however, literature review shows that there are very few applications of nature-inspired metaheuristics to portfolio optimization problem. This is especially true for swarm intelligence algorithms which represent the newer branch of nature-inspired algorithms. No application of any swarm intelligence metaheuristics to cardinality constrained mean-variance (CCMV) portfolio problem with entropy constraint was found in the literature. This paper introduces modified firefly algorithm (FA) for the CCMV portfolio model with entropy constraint. Firefly algorithm is one of the latest, very successful swarm intelligence algorithm; however, it exhibits some deficiencies when applied to constrained problems. To overcome lack of exploration power during early iterations, we modified the algorithm and tested it on standard portfolio benchmark data sets used in the literature. Our proposed modified firefly algorithm proved to be better than other state-of-the-art algorithms, while introduction of entropy diversity constraint further improved results. PMID:24991645
Bacanin, Nebojsa; Tuba, Milan
2014-01-01
Portfolio optimization (selection) problem is an important and hard optimization problem that, with the addition of necessary realistic constraints, becomes computationally intractable. Nature-inspired metaheuristics are appropriate for solving such problems; however, literature review shows that there are very few applications of nature-inspired metaheuristics to portfolio optimization problem. This is especially true for swarm intelligence algorithms which represent the newer branch of nature-inspired algorithms. No application of any swarm intelligence metaheuristics to cardinality constrained mean-variance (CCMV) portfolio problem with entropy constraint was found in the literature. This paper introduces modified firefly algorithm (FA) for the CCMV portfolio model with entropy constraint. Firefly algorithm is one of the latest, very successful swarm intelligence algorithm; however, it exhibits some deficiencies when applied to constrained problems. To overcome lack of exploration power during early iterations, we modified the algorithm and tested it on standard portfolio benchmark data sets used in the literature. Our proposed modified firefly algorithm proved to be better than other state-of-the-art algorithms, while introduction of entropy diversity constraint further improved results.
Wu, Sheng-Jhih; Chu, Moody T.
2017-08-01
An inverse eigenvalue problem usually entails two constraints, one conditioned upon the spectrum and the other on the structure. This paper investigates the problem where triple constraints of eigenvalues, singular values, and diagonal entries are imposed simultaneously. An approach combining an eclectic mix of skills from differential geometry, optimization theory, and analytic gradient flow is employed to prove the solvability of such a problem. The result generalizes the classical Mirsky, Sing-Thompson, and Weyl-Horn theorems concerning the respective majorization relationships between any two of the arrays of main diagonal entries, eigenvalues, and singular values. The existence theory fills a gap in the classical matrix theory. The problem might find applications in wireless communication and quantum information science. The technique employed can be implemented as a first-step numerical method for constructing the matrix. With slight modification, the approach might be used to explore similar types of inverse problems where the prescribed entries are at general locations.
International Nuclear Information System (INIS)
Wu, Sheng-Jhih; Chu, Moody T
2017-01-01
An inverse eigenvalue problem usually entails two constraints, one conditioned upon the spectrum and the other on the structure. This paper investigates the problem where triple constraints of eigenvalues, singular values, and diagonal entries are imposed simultaneously. An approach combining an eclectic mix of skills from differential geometry, optimization theory, and analytic gradient flow is employed to prove the solvability of such a problem. The result generalizes the classical Mirsky, Sing–Thompson, and Weyl-Horn theorems concerning the respective majorization relationships between any two of the arrays of main diagonal entries, eigenvalues, and singular values. The existence theory fills a gap in the classical matrix theory. The problem might find applications in wireless communication and quantum information science. The technique employed can be implemented as a first-step numerical method for constructing the matrix. With slight modification, the approach might be used to explore similar types of inverse problems where the prescribed entries are at general locations. (paper)
Yurtkuran, Alkın
2014-01-01
The traveling salesman problem with time windows (TSPTW) is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA) that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle's boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms. PMID:24723834
Directory of Open Access Journals (Sweden)
Alkın Yurtkuran
2014-01-01
Full Text Available The traveling salesman problem with time windows (TSPTW is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle’s boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms.
F John's stability conditions versus A Carasso's SECB constraint for backward parabolic problems
International Nuclear Information System (INIS)
Lee, Jinwoo; Sheen, Dongwoo
2009-01-01
In order to solve backward parabolic problems John (1960 Commun. Pure. Appl. Math.13 551–85) introduced the two constraints ||u(T)|| ≤ M and ||u(0) − g|| ≤ δ where u(t) satisfies the backward heat equation for t in (0, T) with the initial data u(0). The slow evolution from the continuation boundary (SECB) constraint was introduced by Carasso (1994 SIAM J. Numer. Anal. 31 1535–57) to attain continuous dependence on data for backward parabolic problems even at the continuation boundary t = T. The additional 'SECB constraint' guarantees a significant improvement in stability up to t = T. In this paper, we prove that the same type of stability can be obtained by using only two constraints among the three. More precisely, we show that the a priori boundedness condition ||u(T)|| ≤ M is redundant. This implies that Carasso's SECB condition can be used to replace the a priori boundedness condition of John with an improved stability estimate. Also, a new class of regularized solutions is introduced for backward parabolic problems with an SECB constraint. The new regularized solutions are optimally stable and we also provide a constructive scheme to compute. Finally, numerical examples are provided
A LONGITUDINAL ANALYSIS OF PARENTING PRACTICES, COUPLE SATISFACTION, AND CHILD BEHAVIOR PROBLEMS
Linville, Deanna; Chronister, Krista; Dishion, Tom; Todahl, Jeff; Miller, John; Shaw, Daniel; Gardner, Francis; Wilson, Melvin
2010-01-01
This longitudinal study examined the relationship between couple relationship satisfaction, parenting practices, parent depression, and child problem behaviors. The study participants (n = 148) were part of a larger experimental study that examined the effectiveness of a brief family-centered intervention, the Family Check-Up model. Regression analysis results indicated that our proposed model accounted for 38% of the variance in child problem behavior at Time 2, with child problem behavior a...
A note on existence of mixed solutions to equilibrium problems with equilibrium constraints
Czech Academy of Sciences Publication Activity Database
Červinka, Michal
2007-01-01
Roč. 2007, č. 24 (2007), s. 27-44 ISSN 1212-074X R&D Projects: GA AV ČR IAA1030405 Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with equilibrium constraints * variational analysis * mixed strategy Subject RIV: BA - General Mathematics
A numerical approach to weak Pareto solutions to equilibrium problems with equilibrium constraints
Czech Academy of Sciences Publication Activity Database
Červinka, Michal
2006-01-01
Roč. 57, č. 7 (2006), s. 14-17 ISSN 1335-3632. [ISCAM 2006. International Conference in Applied Mathematics for undergraduate and graduate students. Bratislava, 07.04.2006-08.04.2006] Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with complementarity constraints * multiobjective optimization * variational analysis Subject RIV: BD - Theory of Information
Czech Academy of Sciences Publication Activity Database
Mordukhovich, B. S.; Outrata, Jiří; Červinka, Michal
2007-01-01
Roč. 56, č. 4 (2007), s. 479-494 ISSN 0233-1934 R&D Projects: GA AV ČR IAA1030405 Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with complementarity constraints * multiobjective optimization * necessary optimality conditions * numerical methods * oligopolistic market s Subject RIV: BA - General Mathematics Impact factor: 0.408, year: 2007
DEFF Research Database (Denmark)
Stolpe, Mathias; Stidsen, Thomas K.
2005-01-01
In this paper we present a hierarchical optimization method for finding feasible true 0-1 solutions to finite element based topology design problems. The topology design problems are initially modeled as non-convex mixed 0-1 programs. The hierarchical optimization method is applied to the problem...... and then successively refined as needed. At each level of design mesh refinement, a neighborhood optimization method is used to solve the problem considered. The non-convex topology design problems are equivalently reformulated as convex all-quadratic mixed 0-1 programs. This reformulation enables the use of methods...... of minimizing the weight of a structure subject to displacement and local design-dependent stress constraints. The method iteratively solves a sequence of problems of increasing size of the same type as the original problem. The problems are defined on a design mesh which is initially coarse...
DEFF Research Database (Denmark)
Stolpe, Mathias; Stidsen, Thomas K.
2007-01-01
In this paper, we present a hierarchical optimization method for finding feasible true 0-1 solutions to finite-element-based topology design problems. The topology design problems are initially modelled as non-convex mixed 0-1 programs. The hierarchical optimization method is applied to the problem...... and then successively refined as needed. At each level of design mesh refinement, a neighbourhood optimization method is used to treat the problem considered. The non-convex topology design problems are equivalently reformulated as convex all-quadratic mixed 0-1 programs. This reformulation enables the use of methods...... of minimizing the weight of a structure subject to displacement and local design-dependent stress constraints. The method iteratively treats a sequence of problems of increasing size of the same type as the original problem. The problems are defined on a design mesh which is initially coarse...
Solving the Frequency Assignment Problem by Site Availability and Constraint Programming
Linhares, Andrea Carneiro; Torres-Moreno, Juan-Manuel; Peinl, Peter; Michelon, Philippe
2010-01-01
The efficient use of bandwidth for radio communications becomes more and more crucial when developing new information technologies and their applications. The core issues are addressed by the so-called Frequency Assignment Problems (FAP). Our work investigates static FAP, where an attempt is first made to configure a kernel of links. We study the problem based on the concepts and techniques of Constraint Programming and integrate the site availability concept. Numerical simulations conducted ...
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2014-01-01
Full Text Available We first introduce and analyze one multistep iterative algorithm by hybrid shrinking projection method for finding a solution of the system of generalized equilibria with constraints of several problems: the generalized mixed equilibrium problem, finitely many variational inclusions, the minimization problem for a convex and continuously Fréchet differentiable functional, and the fixed-point problem of an asymptotically strict pseudocontractive mapping in the intermediate sense in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another multistep iterative algorithm involving no shrinking projection method and derive its weak convergence under mild assumptions.
Tabu search approaches for the multi-level warehouse layout problem with adjacency constraints
Zhang, G. Q.; Lai, K. K.
2010-08-01
A new multi-level warehouse layout problem, the multi-level warehouse layout problem with adjacency constraints (MLWLPAC), is investigated. The same item type is required to be located in adjacent cells, and horizontal and vertical unit travel costs are product dependent. An integer programming model is proposed to formulate the problem, which is NP hard. Along with a cube-per-order index policy based heuristic, the standard tabu search (TS), greedy TS, and dynamic neighbourhood based TS are presented to solve the problem. The computational results show that the proposed approaches can reduce the transportation cost significantly.
Zhao, Yingfeng; Liu, Sanyang
2016-01-01
We present a practical branch and bound algorithm for globally solving generalized linear multiplicative programming problem with multiplicative constraints. To solve the problem, a relaxation programming problem which is equivalent to a linear programming is proposed by utilizing a new two-phase relaxation technique. In the algorithm, lower and upper bounds are simultaneously obtained by solving some linear relaxation programming problems. Global convergence has been proved and results of some sample examples and a small random experiment show that the proposed algorithm is feasible and efficient.
A Kind of Nonlinear Programming Problem Based on Mixed Fuzzy Relation Equations Constraints
Li, Jinquan; Feng, Shuang; Mi, Honghai
In this work, a kind of nonlinear programming problem with non-differential objective function and under the constraints expressed by a system of mixed fuzzy relation equations is investigated. First, some properties of this kind of optimization problem are obtained. Then, a polynomial-time algorithm for this kind of optimization problem is proposed based on these properties. Furthermore, we show that this algorithm is optimal for the considered optimization problem in this paper. Finally, numerical examples are provided to illustrate our algorithms.
Cognitive constraints on high school students' representations of real environmental problems
Barnes, Ervin Kenneth
One class of juniors and seniors was studied through one semester in the investigation of how students think about, learn from, and solve real environmental problems. The intention was to listen to student voices while researching the features of their representations of these problems, the beliefs they held (tenets), the cognitive processes they employed, and the principles of science, ecology, problem solving, and ethics they held as tenets. The focus was upon two self-selected groups as they perceived, engaged, analyzed, and proposed solutions for problems. Analysis of the student representations involved interpretation of the features to include both the perspective tenets and the envisioning processes. These processes included the intentive and attentive constraints as tenet acquisition and volitive and agential constraints as tenet affirmation. The perspective tenets included a variety of conceptual (basic science, ecological, ethical, and problem-solving) constraints as well as ontological, epistemological, and other cultural (role, status, power, and community) constraints. The perspective tenets were interpreted thematically including the ways populations of people cause and care about environmental problems, the magnitude of environmental problems and the science involved, the expectations and limitations students perceive for themselves, and the importance of community awareness and cooperation to addressing these problems. Some of these tenets were interpreted to be principles in that they were rules that were accepted by some people as true. The perspective tenets, along with the envisioning processes, were perceived to be the constraints that determined the environmental problems and limited the solution possibilities. The students thought about environmental problems in mature and principled ways using a repertoire of cognitive processes. They learned from them as they acquired and affirmed tenets. They solved them through personal choices and
Tokenplan: A Planner for Both Satisfaction and Optimization Problem
Meiller, Yannick; Fabiani, Patrick
2001-01-01
Tokenplan is a planner based on the use of Petri nets. Its main feature is the flexibility it offers in the way it builds the planning graph. The Fifth International Conference on Artificial Intelligence Planning and Scheduling planning competition validated its behavior with a graphplan-like behavior. The next step is to demonstrate the benefits we expect from our planner in planning problems involving optimization and uncertainty handling.
Two novel classes of solvable many-body problems of goldfish type with constraints
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Calogero, F [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , 00185 Rome (Italy); Gomez-Ullate, D [Departamento de Fisica Teorica II, Universidad Complutense, 28040 Madrid (Spain)
2007-05-18
Two novel classes of many-body models with nonlinear interactions 'of goldfish type' are introduced. They are solvable provided the initial data satisfy a single constraint (in one case; in the other, two constraints), i.e., for such initial data the solution of their initial-value problem can be achieved via algebraic operations, such as finding the eigenvalues of given matrices or equivalently the zeros of known polynomials. Entirely isochronous versions of some of these models are also exhibited, i.e., versions of these models whose nonsingular solutions are all completely periodic with the same period.
Amallynda, I.; Santosa, B.
2017-11-01
This paper proposes a new generalization of the distributed parallel machine and assembly scheduling problem (DPMASP) with eligibility constraints referred to as the modified distributed parallel machine and assembly scheduling problem (MDPMASP) with eligibility constraints. Within this generalization, we assume that there are a set non-identical factories or production lines, each one with a set unrelated parallel machine with different speeds in processing them disposed to a single assembly machine in series. A set of different products that are manufactured through an assembly program of a set of components (jobs) according to the requested demand. Each product requires several kinds of jobs with different sizes. Beside that we also consider to the multi-objective problem (MOP) of minimizing mean flow time and the number of tardy products simultaneously. This is known to be NP-Hard problem, is important to practice, as the former criterions to reflect the customer's demand and manufacturer's perspective. This is a realistic and complex problem with wide range of possible solutions, we propose four simple heuristics and two metaheuristics to solve it. Various parameters of the proposed metaheuristic algorithms are discussed and calibrated by means of Taguchi technique. All proposed algorithms are tested by Matlab software. Our computational experiments indicate that the proposed problem and fourth proposed algorithms are able to be implemented and can be used to solve moderately-sized instances, and giving efficient solutions, which are close to optimum in most cases.
Gudjonsson, Gisli H.; Sigurdsson, Jon Fridrik; Eyjolfsdottir, Gudrun Agusta; Smari, Jakob; Young, Susan
2009-01-01
Objective: To ascertain whether ADHD symptoms, and associated problems, are negatively related to subjective well-being. Method: The Satisfaction With Life Scale (SWLS) was completed by 369 university students, along with the Reasoning & Rehabilitation (R&R) ADHD Training Evaluation (RATE), the "Diagnostic and Statistical Manual of…
A Bee Colony Optimization Approach for Mixed Blocking Constraints Flow Shop Scheduling Problems
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Mostafa Khorramizadeh
2015-01-01
Full Text Available The flow shop scheduling problems with mixed blocking constraints with minimization of makespan are investigated. The Taguchi orthogonal arrays and path relinking along with some efficient local search methods are used to develop a metaheuristic algorithm based on bee colony optimization. In order to compare the performance of the proposed algorithm, two well-known test problems are considered. Computational results show that the presented algorithm has comparative performance with well-known algorithms of the literature, especially for the large sized problems.
Zeb, Salman; Yousaf, Muhammad
2017-01-01
In this article, we present a QR updating procedure as a solution approach for linear least squares problem with equality constraints. We reduce the constrained problem to unconstrained linear least squares and partition it into a small subproblem. The QR factorization of the subproblem is calculated and then we apply updating techniques to its upper triangular factor R to obtain its solution. We carry out the error analysis of the proposed algorithm to show that it is backward stable. We also illustrate the implementation and accuracy of the proposed algorithm by providing some numerical experiments with particular emphasis on dense problems.
Financial Management and Financial Problems As They Relate to Marital Satisfaction in Early Marriage
Kerkmann, Barbara C.
1998-01-01
The financial management habits and perceptions of young married couples were examined, as well as their financial problems and perceptions of their problems' magnitude in an attempt to assess the relationship of these financial factors to marital satisfaction. A survey was delivered to 604 residents of family student housing at Utah State University. The spouse who predominantly handled family finances was asked to complete the survey. By using an incentive for completing the survey, a respo...
Detection of Common Problems in Real-Time and Multicore Systems Using Model-Based Constraints
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Raphaël Beamonte
2016-01-01
Full Text Available Multicore systems are complex in that multiple processes are running concurrently and can interfere with each other. Real-time systems add on top of that time constraints, making results invalid as soon as a deadline has been missed. Tracing is often the most reliable and accurate tool available to study and understand those systems. However, tracing requires that users understand the kernel events and their meaning. It is therefore not very accessible. Using modeling to generate source code or represent applications’ workflow is handy for developers and has emerged as part of the model-driven development methodology. In this paper, we propose a new approach to system analysis using model-based constraints, on top of userspace and kernel traces. We introduce the constraints representation and how traces can be used to follow the application’s workflow and check the constraints we set on the model. We then present a number of common problems that we encountered in real-time and multicore systems and describe how our model-based constraints could have helped to save time by automatically identifying the unwanted behavior.
Hussain, Nur Farahin Mee; Zahid, Zalina
2014-12-01
Nowadays, in the job market demand, graduates are expected not only to have higher performance in academic but they must also be excellent in soft skill. Problem-Based Learning (PBL) has a number of distinct advantages as a learning method as it can deliver graduates that will be highly prized by industry. This study attempts to determine the satisfaction level of engineering students on the PBL Approach and to evaluate their determinant factors. The Structural Equation Modeling (SEM) was used to investigate how the factors of Good Teaching Scale, Clear Goals, Student Assessment and Levels of Workload affected the student satisfaction towards PBL approach.
Constraint-based Student Modelling in Probability Story Problems with Scaffolding Techniques
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Nabila Khodeir
2018-01-01
Full Text Available Constraint-based student modelling (CBM is an important technique employed in intelligent tutoring systems to model student knowledge to provide relevant assistance. This paper introduces the Math Story Problem Tutor (MAST, a Web-based intelligent tutoring system for probability story problems, which is able to generate problems of different contexts, types and difficulty levels for self-paced learning. Constraints in MAST are specified at a low-level of granularity to allow fine-grained diagnosis of the student error. Furthermore, MAST extends CBM to address errors due to misunderstanding of the narrative story. It can locate and highlight keywords that may have been overlooked or misunderstood leading to an error. This is achieved by utilizing the role of sentences and keywords that are defined through the Natural Language Generation (NLG methods deployed in the story problem generation. MAST also integrates CBM with scaffolding questions and feedback to provide various forms of help and guidance to the student. This allows the student to discover and correct any errors in his/her solution. MAST has been preliminary evaluated empirically and the results show the potential effectiveness in tutoring students with a decrease in the percentage of violated constraints along the learning curve. Additionally, there is a significant improvement in the results of the post–test exam in comparison to the pre-test exam of the students using MAST in comparison to those relying on the textbook
Henderson, A. Davis; Sayger, Thomas V.; Horne, Arthur M.
2003-01-01
Assesses the interacting relationship between child behavior problems, marital satisfaction, maternal depression, and family cohesion in 43 mothers and school-aged boys. Results suggest that mothers with depressive symptoms report lower levels of marital satisfaction and higher levels of child behavior problems. Findings also suggest that maternal…
Diulio, Andrea R; Cero, Ian; Witte, Tracy K; Correia, Christopher J
2014-04-01
The present study investigated the role specific types of alcohol-related problems and life satisfaction play in predicting motivation to change alcohol use. Participants were 548 college students mandated to complete a brief intervention following an alcohol-related policy violation. Using hierarchical multiple regression, we tested for the presence of interaction and quadratic effects on baseline data collected prior to the intervention. A significant interaction indicated that the relationship between a respondent's personal consequences and his/her motivation to change differs depending upon the level of concurrent social consequences. Additionally quadratic effects for abuse/dependence symptoms and life satisfaction were found. The quadratic probes suggest that abuse/dependence symptoms and poor life satisfaction are both positively associated with motivation to change for a majority of the sample; however, the nature of these relationships changes for participants with more extreme scores. Results support the utility of using a multidimensional measure of alcohol related problems and assessing non-linear relationships when assessing predictors of motivation to change. The results also suggest that the best strategies for increasing motivation may vary depending on the types of alcohol-related problems and level of life satisfaction the student is experiencing and highlight potential directions for future research. Copyright © 2014. Published by Elsevier Ltd.
International Nuclear Information System (INIS)
Jian Jinbao; Li Jianling; Mo Xingde
2006-01-01
This paper discusses a kind of optimization problem with linear complementarity constraints, and presents a sequential quadratic programming (SQP) algorithm for solving a stationary point of the problem. The algorithm is a modification of the SQP algorithm proposed by Fukushima et al. [Computational Optimization and Applications, 10 (1998),5-34], and is based on a reformulation of complementarity condition as a system of linear equations. At each iteration, one quadratic programming and one system of equations needs to be solved, and a curve search is used to yield the step size. Under some appropriate assumptions, including the lower-level strict complementarity, but without the upper-level strict complementarity for the inequality constraints, the algorithm is proved to possess strong convergence and superlinear convergence. Some preliminary numerical results are reported
Khanh, Phan Quoc; Plubtieng, Somyot; Sombut, Kamonrat
2014-01-01
The purpose of this paper is introduce several types of Levitin-Polyak well-posedness for bilevel vector equilibrium and optimization problems with equilibrium constraints. Base on criterion and characterizations for these types of Levitin-Polyak well-posedness we argue on diameters and Kuratowski’s, Hausdorff’s, or Istrǎtescus measures of noncompactness of approximate solution sets under suitable conditions, and we prove the Levitin-Polyak well-posedness for bilevel vector equilibrium and op...
Solving quantum optimal control problems using Clebsch variables and Lin constraints
Delgado-Téllez, M.; Ibort, A.; Rodríguez de la Peña, T.
2018-01-01
Clebsch variables (and Lin constraints) are applied to the study of a class of optimal control problems for affine-controlled quantum systems. The optimal control problem will be modelled with controls defined on an auxiliary space where the dynamical group of the system acts freely. The reciprocity between both theories: the classical theory defined by the objective functional and the quantum system, is established by using a suitable version of Lagrange’s multipliers theorem and a geometrical interpretation of the constraints of the system as defining a subspace of horizontal curves in an associated bundle. It is shown how the solutions of the variational problem defined by the objective functional determine solutions of the quantum problem. Then a new way of obtaining explicit solutions for a family of optimal control problems for affine-controlled quantum systems (finite or infinite dimensional) is obtained. One of its main advantages, is the the use of Clebsch variables allows to compute such solutions from solutions of invariant problems that can often be computed explicitly. This procedure can be presented as an algorithm that can be applied to a large class of systems. Finally, some simple examples, spin control, a simple quantum Hamiltonian with an ‘Elroy beanie’ type classical model and a controlled one-dimensional quantum harmonic oscillator, illustrating the main features of the theory, will be discussed.
DDeveloping and solving a bi-objective joint replenishment problem under storing space constraint
Directory of Open Access Journals (Sweden)
ommolbanin yousefi
2011-03-01
Full Text Available In this research, a bi-objective joint replenishment problem has been developed and solved with the assumption of one restricted resource. The proposed model has a storing space constraint and tries to optimize two objective functions simultaneously. They include minimizing annual holding and setup costs and minimizing annual inventory investment. Then, for solving this problem, a multi-objective genetic algorithm (MOGA has been developed. In order to analyze the algorithm efficiency, its performance has been examined in solving 1600 randomly produced problems using parameters extracted from literature. The findings imply that the proposed algorithm is capable of producing a good set of Pareto optimal solutions. Finally, the application of the problem solving approach and the findings of the proposed algorithm have been illustrated for a special problem, which has been randomly produced.
Heijink, H.J.I.C.M.
2002-01-01
We investigated two redundancy control problems related to music performance, one in computer science and one in motor control research, viz., score-performance matching and guitar fingering. In score-performance matching, a score and a performance have to be compared note by note to find the
An Adaptive Evolutionary Algorithm for Traveling Salesman Problem with Precedence Constraints
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Jinmo Sung
2014-01-01
Full Text Available Traveling sales man problem with precedence constraints is one of the most notorious problems in terms of the efficiency of its solution approach, even though it has very wide range of industrial applications. We propose a new evolutionary algorithm to efficiently obtain good solutions by improving the search process. Our genetic operators guarantee the feasibility of solutions over the generations of population, which significantly improves the computational efficiency even when it is combined with our flexible adaptive searching strategy. The efficiency of the algorithm is investigated by computational experiments.
Constraint optimization model of a scheduling problem for a robotic arm in automatic systems
DEFF Research Database (Denmark)
Kristiansen, Ewa; Smith, Stephen F.; Kristiansen, Morten
2014-01-01
are characteristics of the painting process application itself. Unlike spot-welding, painting tasks require movement of the entire robot arm. In addition to minimizing intertask duration, the scheduler must strive to maximize painting quality and the problem is formulated as a multi-objective optimization problem....... The scheduling model is implemented as a stand-alone module using constraint programming, and integrated with a larger automatic system. The results of a number of simulation experiments with simple parts are reported, both to characterize the functionality of the scheduler and to illustrate the operation...... of the entire software system for automatic generation of robot programs for painting....
Heijink, H.J.I.C.M.
2002-01-01
We investigated two redundancy control problems related to music performance, one in computer science and one in motor control research, viz., score-performance matching and guitar fingering. In score-performance matching, a score and a performance have to be compared note by note to find the optimal correspondence between the two. There are exponentially many possible correspondences, but we found that a general algorithmic technique that uses structural information in the score performs wel...
Directory of Open Access Journals (Sweden)
Renata Melo e Silva de Oliveira
2015-03-01
Full Text Available Scheduling is a key factor for operations management as well as for business success. From industrial Job-shop Scheduling problems (JSSP, many optimization challenges have emerged since de 1960s when improvements have been continuously required such as bottlenecks allocation, lead-time reductions and reducing response time to requests. With this in perspective, this work aims to discuss 3 different optimization models for minimizing Makespan. Those 3 models were applied on 17 classical problems of examples JSSP and produced different outputs. The first model resorts on Mixed and Integer Programming (MIP and it resulted on optimizing 60% of the studied problems. The other models were based on Constraint Programming (CP and approached the problem in two different ways: a model CP1 is a standard IBM algorithm whereof restrictions have an interval structure that fail to solve 53% of the proposed instances, b Model CP-2 approaches the problem with disjunctive constraints and optimized 88% of the instances. In this work, each model is individually analyzed and then compared considering: i Optimization success performance, ii Computational processing time, iii Greatest Resource Utilization and, iv Minimum Work-in-process Inventory. Results demonstrated that CP-2 presented best results on criteria i and ii, but MIP was superior on criteria iii and iv and those findings are discussed at the final section of this work.
Problem-based learning in laboratory medicine resident education: a satisfaction survey.
Lepiller, Quentin; Solis, Morgane; Velay, Aurélie; Gantner, Pierre; Sueur, Charlotte; Stoll-Keller, Françoise; Barth, Heidi; Fafi-Kremer, Samira
2017-04-01
Theoretical knowledge in biology and medicine plays a substantial role in laboratory medicine resident education. In this study, we assessed the contribution of problem-based learning (PBL) to improve the training of laboratory medicine residents during their internship in the department of virology, Strasbourg University Hospital, France. We compared the residents' satisfaction regarding an educational program based on PBL and a program based on lectures and presentations. PBL induced a high level of satisfaction (100%) among residents compared to lectures and presentations (53%). The main advantages of this technique were to create a situational interest regarding virological problems, to boost the residents' motivation and to help them identify the most relevant learning objectives in virology. However, it appears pertinent to educate the residents in appropriate bibliographic research techniques prior to PBL use and to monitor their learning by regular formative assessment sessions.
XY vs X Mixer in Quantum Alternating Operator Ansatz for Optimization Problems with Constraints
Wang, Zhihui; Rubin, Nicholas; Rieffel, Eleanor G.
2018-01-01
Quantum Approximate Optimization Algorithm, further generalized as Quantum Alternating Operator Ansatz (QAOA), is a family of algorithms for combinatorial optimization problems. It is a leading candidate to run on emerging universal quantum computers to gain insight into quantum heuristics. In constrained optimization, penalties are often introduced so that the ground state of the cost Hamiltonian encodes the solution (a standard practice in quantum annealing). An alternative is to choose a mixing Hamiltonian such that the constraint corresponds to a constant of motion and the quantum evolution stays in the feasible subspace. Better performance of the algorithm is speculated due to a much smaller search space. We consider problems with a constant Hamming weight as the constraint. We also compare different methods of generating the generalized W-state, which serves as a natural initial state for the Hamming-weight constraint. Using graph-coloring as an example, we compare the performance of using XY model as a mixer that preserves the Hamming weight with the performance of adding a penalty term in the cost Hamiltonian.
Lim, Cristina P.; Matsuda, Yoshiaki; Shigemi, Yukio
1995-11-01
The Philippine fisheries accounted for 3.7% of the gross national product at current prices. The sector employed about 990,872 persons. Of the divisions comprising the industry, municipal fisheries continued to contribute the largest share of fish production. However, the sector is beset with problems, many of which are best examplified by the case of San Miguel Bay (SMB). This paper presents the problems and constraints confronting SMB, a common property resource. This bay's open access condition has led to various problems, such as declining fishery resources, depressed socioeconomic conditions, illegal fishing, increasing population, and conflict among resource users. A poor marketing system, low level of fishing technology, fishermen's noncompliance and authorities' lax enforcement of rules and regulations, as well as lack of alternative sources of income further characterize the condition in SMB. Establishment of fishing rights, improvement of the marketing system, provision of alternative sources of income, and improvement of fishing technology were some of the solutions suggested. One major constraint, however, is financial, Comanagement complemented with other management tools has been proposed in addressing the problems in SMB.
Neural Based Tabu Search method for solving unit commitment problem with cooling-banking constraints
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Rajan Asir Christober Gnanakkan Charles
2009-01-01
Full Text Available This paper presents a new approach to solve short-term unit commitment problem (UCP using Neural Based Tabu Search (NBTS with cooling and banking constraints. The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. This also means that it is desirable to find the optimal generating unit commitment in the power system for next H hours. A 7-unit utility power system in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different IEEE test systems consist of 10, 26 and 34 units. Numerical results are shown to compare the superiority of the cost solutions obtained using the Tabu Search (TS method, Dynamic Programming (DP and Lagrangian Relaxation (LR methods in reaching proper unit commitment.
Directory of Open Access Journals (Sweden)
Jingling Zhang
2012-01-01
Full Text Available The multiobjective vehicle routing problem considering customer satisfaction (MVRPCS involves the distribution of orders from several depots to a set of customers over a time window. This paper presents a self-adaptive grid multi-objective quantum evolutionary algorithm (MOQEA for the MVRPCS, which takes into account customer satisfaction as well as travel costs. The degree of customer satisfaction is represented by proposing an improved fuzzy due-time window, and the optimization problem is modeled as a mixed integer linear program. In the MOQEA, nondominated solution set is constructed by the Challenge Cup rules. Moreover, an adaptive grid is designed to achieve the diversity of solution sets; that is, the number of grids in each generation is not fixed but is automatically adjusted based on the distribution of the current generation of nondominated solution set. In the study, the MOQEA is evaluated by applying it to classical benchmark problems. Results of numerical simulation and comparison show that the established model is valid and the MOQEA is effective for MVRPCS.
Solution Method of Multi-Product Two-Stage Logistics Problem with Constraints of Delivery Course
Ataka, Shinichiro; Gen, Mitsuo
The logistics network design is one of the important phase of Supply Chain Management (SCM) and it is the problem that should be optimized for long-term promotion of efficiency of the whole supply chain. Usually a plant produces different type of products. Even if it is a factory of the same company, delivery is different by a kind of a produced product. The restrictions which this model has are deeply concerned with TP in the real world. In this paper, we consider the logistics network design problems with multi-products and constraints for delivery course. To solve the problem, we used a hybrid priority-based Genetic Algorithm (h-priGA), and we tried the comparison experiment with priority-based Genetic Algorithm (priGA)and h-priGA, we show it about the effectiveness of h-priGA.
A balancing domain decomposition method by constraints for advection-diffusion problems
Energy Technology Data Exchange (ETDEWEB)
Tu, Xuemin; Li, Jing
2008-12-10
The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A pre-conditioned GMRES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially sub-assembled finite element problem is solved. A convergence rate estimate for the GMRES iteration is established, under the condition that the diameters of subdomains are small enough. It is independent of the number of subdomains and grows only slowly with the subdomain problem size. Numerical experiments for several two-dimensional advection-diffusion problems illustrate the fast convergence of the proposed algorithm.
Exact Solution of a Constraint Optimization Problem for the Thermoelectric Figure of Merit
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Wolfgang Seifert
2012-03-01
Full Text Available In the classical theory of thermoelectricity, the performance integrals for a fully self-compatible material depend on the dimensionless figure of merit zT. Usually these integrals are evaluated for constraints z = const. and zT = const., respectively. In this paper we discuss the question from a mathematical point of view whether there is an optimal temperature characteristics of the figure of merit. We solve this isoperimetric variational problem for the best envelope of a family of curves z(TT.
Exact Solution of a Constraint Optimization Problem for the Thermoelectric Figure of Merit.
Seifert, Wolfgang; Pluschke, Volker
2012-03-21
In the classical theory of thermoelectricity, the performance integrals for a fully self-compatible material depend on the dimensionless figure of merit zT. Usually these integrals are evaluated for constraints z = const. and zT = const., respectively. In this paper we discuss the question from a mathematical point of view whether there is an optimal temperature characteristics of the figure of merit. We solve this isoperimetric variational problem for the best envelope of a family of curves z(T)T.
Savundranayagam, Marie Y; Lee, Christopher
2017-03-01
This study investigated the impact of dementia-related communication difficulties and communication strategies used by staff on resident-related indicators of role demand and role satisfaction. Formal/paid long-term care staff caregivers (N = 109) of residents with dementia completed questionnaires on dementia-related communication difficulties, communication strategies, role demand (ie, residents make unreasonable demands), and role satisfaction (measured by relationship closeness and influence over residents). Three types of communication strategies were included: (a) effective repair strategies, (b) completing actions by oneself, and (c) tuning out or ignoring the resident. Analyses using structural equation modeling revealed that communication problems were positively linked with role demand. Repair strategies were positively linked with relationship closeness and influence over residents. Completing actions by oneself was positively linked to role demand and influence over residents, whereas tuning out was negatively linked with influence over residents. The findings underscore that effective caregiver communication skills are essential in enhancing staff-resident relationships.
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Katarina Pažur Aničić
2016-12-01
Full Text Available This paper describes the implementation of problem-based learning (PBL principles in an undergraduate IT service management course, followed by the results about student satisfaction and work performance. The results indicate the students’ general satisfaction with the course implementation, as well as some challenges regarding the self-assessment and peer assessment of their work. The findings also reveal the students’ better work performance in project results than in traditional knowledge tests, which reinforces the indications about their positive attitudes towards the interactive PBL environment. The cluster analyses identified seven different patterns in student behaviour regarding course performance. The presented results can be considered a new aspect of the development and amendment of the information and communication technology (ICT skills requested by future employers. In this regard, the demand for innovation in the education of future ICT professionals arises from the need for experts equipped with both IT and business skills.
Qin, Sitian; Yang, Xiudong; Xue, Xiaoping; Song, Jiahui
2017-10-01
Pseudoconvex optimization problem, as an important nonconvex optimization problem, plays an important role in scientific and engineering applications. In this paper, a recurrent one-layer neural network is proposed for solving the pseudoconvex optimization problem with equality and inequality constraints. It is proved that from any initial state, the state of the proposed neural network reaches the feasible region in finite time and stays there thereafter. It is also proved that the state of the proposed neural network is convergent to an optimal solution of the related problem. Compared with the related existing recurrent neural networks for the pseudoconvex optimization problems, the proposed neural network in this paper does not need the penalty parameters and has a better convergence. Meanwhile, the proposed neural network is used to solve three nonsmooth optimization problems, and we make some detailed comparisons with the known related conclusions. In the end, some numerical examples are provided to illustrate the effectiveness of the performance of the proposed neural network.
Czech Academy of Sciences Publication Activity Database
Červinka, Michal
2010-01-01
Roč. 2010, č. 4 (2010), s. 730-753 ISSN 0023-5954 Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with complementarity constraints * homotopy * C-stationarity Subject RIV: BC - Control Systems Theory Impact factor: 0.461, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/cervinka-on computation of c-stationary points for equilibrium problems with linear complementarity constraints via homotopy method.pdf
Constraints on decay plus oscillation solutions of the solar neutrino problem
Joshipura, Anjan S.; Massó, Eduard; Mohanty, Subhendra
2002-12-01
We examine the constraints on the nonradiative decay of neutrinos from the observations of solar neutrino experiments. The standard oscillation hypothesis among three neutrinos solves the solar and atmospheric neutrino problems. The decay of a massive neutrino mixed with the electron neutrino results in the depletion of the solar neutrino flux. We introduce neutrino decay in the oscillation hypothesis and demand that decay does not spoil the successful explanation of solar and atmospheric observations. We obtain a lower bound on the ratio of the lifetime over the mass of ν2, τ2/m2>22.7 s/MeV for the Mikheyev-Smirnov-Wolfenstein solution of the solar neutrino problem and τ2/m2>27.8 s/MeV for the vacuum oscillation solution (at 99% C.L.).
Energy Technology Data Exchange (ETDEWEB)
Jacob Raglend, I. [School of Electrical Sciences, Noorul Islam University, Kumaracoil 629 180 (India); Veeravalli, Sowjanya; Sailaja, Kasanur; Sudheera, B. [School of Electrical Sciences, Vellore Institute of Technology, Vellore 632 004 (India); Kothari, D.P. [FNAE, FNASC, SMIEEE, Vellore Institute of Technology University, Vellore 632 014 (India)
2010-07-15
A comparative study has been made on the solutions obtained using combined economic emission dispatch (CEED) problem considering line flow constraints using different intelligent techniques for the regulated power system to ensure a practical, economical and secure generation schedule. The objective of the paper is to minimize the total production cost of the power generation. Economic load dispatch (ELD) and economic emission dispatch (EED) have been applied to obtain optimal fuel cost of generating units. Combined economic emission dispatch (CEED) is obtained by considering both the economic and emission objectives. This bi-objective CEED problem is converted into single objective function using price penalty factor approach. In this paper, intelligent techniques such as genetic algorithm (GA), evolutionary programming (EP), particle swarm optimization (PSO), differential evolution (DE) are applied to obtain CEED solutions for the IEEE 30-bus system and 15-unit system. This proposed algorithm introduces an efficient CEED approach that obtains the minimum operating cost satisfying unit, emission and network constraints. The proposed algorithm has been tested on two sample systems viz the IEEE 30-bus system and a 15-unit system. The results obtained by the various artificial intelligent techniques are compared with respect to the solution time, total production cost and convergence criteria. The solutions obtained are quite encouraging and useful in the economic emission environment. The algorithm and simulation are carried out using Matlab software. (author)
International Nuclear Information System (INIS)
Jacob Raglend, I.; Veeravalli, Sowjanya; Sailaja, Kasanur; Sudheera, B.; Kothari, D.P.
2010-01-01
A comparative study has been made on the solutions obtained using combined economic emission dispatch (CEED) problem considering line flow constraints using different intelligent techniques for the regulated power system to ensure a practical, economical and secure generation schedule. The objective of the paper is to minimize the total production cost of the power generation. Economic load dispatch (ELD) and economic emission dispatch (EED) have been applied to obtain optimal fuel cost of generating units. Combined economic emission dispatch (CEED) is obtained by considering both the economic and emission objectives. This bi-objective CEED problem is converted into single objective function using price penalty factor approach. In this paper, intelligent techniques such as genetic algorithm (GA), evolutionary programming (EP), particle swarm optimization (PSO), differential evolution (DE) are applied to obtain CEED solutions for the IEEE 30-bus system and 15-unit system. This proposed algorithm introduces an efficient CEED approach that obtains the minimum operating cost satisfying unit, emission and network constraints. The proposed algorithm has been tested on two sample systems viz the IEEE 30-bus system and a 15-unit system. The results obtained by the various artificial intelligent techniques are compared with respect to the solution time, total production cost and convergence criteria. The solutions obtained are quite encouraging and useful in the economic emission environment. The algorithm and simulation are carried out using Matlab software. (author)
Energy Technology Data Exchange (ETDEWEB)
Cho, Su Gil; Jang, Jun Yong; Kim, Ji Hoon; Lee, Tae Hee [Hanyang University, Seoul (Korea, Republic of); Lee, Min Uk [Romax Technology Ltd., Seoul (Korea, Republic of); Choi, Jong Su; Hong, Sup [Korea Research Institute of Ships and Ocean Engineering, Daejeon (Korea, Republic of)
2015-04-15
Sequential surrogate model-based global optimization algorithms, such as super-EGO, have been developed to increase the efficiency of commonly used global optimization technique as well as to ensure the accuracy of optimization. However, earlier studies have drawbacks because there are three phases in the optimization loop and empirical parameters. We propose a united sampling criterion to simplify the algorithm and to achieve the global optimum of problems with constraints without any empirical parameters. It is able to select the points located in a feasible region with high model uncertainty as well as the points along the boundary of constraint at the lowest objective value. The mean squared error determines which criterion is more dominant among the infill sampling criterion and boundary sampling criterion. Also, the method guarantees the accuracy of the surrogate model because the sample points are not located within extremely small regions like super-EGO. The performance of the proposed method, such as the solvability of a problem, convergence properties, and efficiency, are validated through nonlinear numerical examples with disconnected feasible regions.
Job Satisfaction And Family Happiness : The Part-Time Work Problem
Booth, A.L.; van Ours, J.C.
2007-01-01
Using fixed effects ordered logit estimation, we investigate the relationship between part-time work and working hours satisfaction; job satisfaction; and life satisfaction. We account for interdependence within the family using data on partnered men and women from the British Household Panel Survey. We find that men have the highest hours-of-work satisfaction if they work full-time without overtime hours but neither their job satisfaction nor their life satisfaction are affected by how many ...
Albarrak, Ahmed I; Mohammed, Rafiuddin; Abalhassan, Mohammed F; Almutairi, Nasser K
2013-11-01
To evaluate the academic satisfaction and importance among traditional learning (TL) and problem based learning (PBL) medical students, and to further evaluate the areas of concern in the academic education from the student's point of view. A cross sectional study was conducted at the College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia from May to June 2012. The survey questionnaires were self-administered and consisted of mainly 6 sections: teaching, learning, supervision, course organization, information technology (IT) facilities, and development of skills. A total of 92 TL (males: 66 [71.7%]; females: 26 [28.3%]), and 108 PBL (males: 84 [77.8%]; females: 24 [22.1%]), with a mean age of 21.3 +/- 1.3 (TL), and 20.7 +/- 1.0 (PBL) were included in the study. The overall satisfaction rate was higher in the PBL students when compared with TL students in: teaching (84.7%/60.3%); learning (81.4%/64.5%); supervision (80%/51.5%); course organization (69.3%/46.9%); IT facilities (74.0%/58.9%); and development of skills (79.1%/53.9%). There was statistical significance difference in academic satisfaction comparing both groups of students (pdisadvantages of the traditional system. The PBL was potentially considered a successful method in enhancing medical education.
Låftman, Sara B; Modin, Bitte
2017-10-13
Bullying is a major problem in schools and a large number of studies have demonstrated that victims have a high excess risk of poor mental health. It may however also affect those who are not directly victimized by peers. The present study investigates whether peer victimization among classmates is linked to internalizing problems, self-esteem, and life satisfaction at the individual level, when the student's own victimization has been taken into account. The data were derived from the first wave of the Swedish part of Youth in Europe Study (YES!), including information on 4319 students in grade 8 (14-15 years of age) distributed across 242 classes. Results from multilevel analyses show a significant association between classes with a high proportion of students being victimized and higher levels of internalizing problems, lower self-esteem, and lower life satisfaction at the student level. This association holds when the student's own victimization has been taken into account. This suggests that peer victimization negatively affects those who are directly exposed, as well as their classmates. We conclude that efficient methods and interventions to reduce bullying in school are likely to benefit not only those who are victimized, but all students.
Directory of Open Access Journals (Sweden)
Sara B. Låftman
2017-10-01
Full Text Available Bullying is a major problem in schools and a large number of studies have demonstrated that victims have a high excess risk of poor mental health. It may however also affect those who are not directly victimized by peers. The present study investigates whether peer victimization among classmates is linked to internalizing problems, self-esteem, and life satisfaction at the individual level, when the student’s own victimization has been taken into account. The data were derived from the first wave of the Swedish part of Youth in Europe Study (YES!, including information on 4319 students in grade 8 (14–15 years of age distributed across 242 classes. Results from multilevel analyses show a significant association between classes with a high proportion of students being victimized and higher levels of internalizing problems, lower self-esteem, and lower life satisfaction at the student level. This association holds when the student’s own victimization has been taken into account. This suggests that peer victimization negatively affects those who are directly exposed, as well as their classmates. We conclude that efficient methods and interventions to reduce bullying in school are likely to benefit not only those who are victimized, but all students.
yoder, M. R.; Rundle, J. B.; Turcotte, D. L.
2012-12-01
The difficulty of forecasting earthquakes can fundamentally be attributed to the self-similar, or "1/f", nature of seismic sequences. Specifically, the rate of occurrence of earthquakes is inversely proportional to their magnitude m, or more accurately to their scalar moment M. With respect to this "1/f problem," it can be argued that catalog selection (or equivalently, determining catalog constraints) constitutes the most significant challenge to seismicity based earthquake forecasting. Here, we address and introduce a potential solution to this most daunting problem. Specifically, we introduce a framework to constrain, or partition, an earthquake catalog (a study region) in order to resolve local seismicity. In particular, we combine Gutenberg-Richter (GR), rupture length, and Omori scaling with various empirical measurements to relate the size (spatial and temporal extents) of a study area (or bins within a study area) to the local earthquake magnitude potential - the magnitude of earthquake the region is expected to experience. From this, we introduce a new type of time dependent hazard map for which the tuning parameter space is nearly fully constrained. In a similar fashion, by combining various scaling relations and also by incorporating finite extents (rupture length, area, and duration) as constraints, we develop a method to estimate the Omori (temporal) and spatial aftershock decay parameters as a function of the parent earthquake's magnitude m. From this formulation, we develop an ETAS type model that overcomes many point-source limitations of contemporary ETAS. These models demonstrate promise with respect to earthquake forecasting applications. Moreover, the methods employed suggest a general framework whereby earthquake and other complex-system, 1/f type, problems can be constrained from scaling relations and finite extents.; Record-breaking hazard map of southern California, 2012-08-06. "Warm" colors indicate local acceleration (elevated hazard
Lykins, Amy D; Janssen, Erick; Newhouse, Sarah; Heiman, Julia R; Rafaeli, Eshkol
2012-05-01
Despite the importance of sexuality for romantic relationships, there has been little research attention to individual differences and dyadic variables, including couple similarity, and their association with sexual problems and satisfaction. The current study examined the effects of the propensity for sexual inhibition and sexual excitation scales (SIS/SES) and the effects of different mood states on sexuality (Mood and Sexuality Questionnaire [MSQ]), at both the individual and the dyad level, on sexual arousal problems and sexual satisfaction. Similarity in SIS/SES and MSQ was measured in a nonclinical sample of 35 newlywed couples and operationally defined as the within-couple, z-transformed correlations between the two partners' item responses. Sexual arousal problems were assessed using self-report measures (Demographic and Sexual History Questionnaire) and focused on the past 3 months. Sexual satisfaction was assessed using the Global Measure of Sexual Satisfaction. Regression analyses revealed that greater similarity in the effects of anxiety and stress on sexuality was associated with more reported sexual arousal problems of wives. In contrast, the husbands' sexual arousal problems were related only to their own higher SIS1 scores. Higher SES scores predicted lower sexual satisfaction for both husbands and wives. Wives who reported strong positive mood effects on their sexuality indicated greater sexual satisfaction, while husbands who were more similar to their wives in the effect of positive moods on sexuality indicated greater sexual satisfaction. The findings show that, above and beyond one's own sexual propensities, similarity in various aspects of sexuality predicts sexual problems (more so in women) and sexual satisfaction (in both men and women). © 2012 International Society for Sexual Medicine.
Preconditioned alternating direction method of multipliers for inverse problems with constraints
International Nuclear Information System (INIS)
Jiao, Yuling; Jin, Qinian; Lu, Xiliang; Wang, Weijie
2017-01-01
We propose a preconditioned alternating direction method of multipliers (ADMM) to solve linear inverse problems in Hilbert spaces with constraints, where the feature of the sought solution under a linear transformation is captured by a possibly non-smooth convex function. During each iteration step, our method avoids solving large linear systems by choosing a suitable preconditioning operator. In case the data is given exactly, we prove the convergence of our preconditioned ADMM without assuming the existence of a Lagrange multiplier. In case the data is corrupted by noise, we propose a stopping rule using information on noise level and show that our preconditioned ADMM is a regularization method; we also propose a heuristic rule when the information on noise level is unavailable or unreliable and give its detailed analysis. Numerical examples are presented to test the performance of the proposed method. (paper)
Homotopy Algorithm for Optimal Control Problems with a Second-order State Constraint
International Nuclear Information System (INIS)
Hermant, Audrey
2010-01-01
This paper deals with optimal control problems with a regular second-order state constraint and a scalar control, satisfying the strengthened Legendre-Clebsch condition. We study the stability of structure of stationary points. It is shown that under a uniform strict complementarity assumption, boundary arcs are stable under sufficiently smooth perturbations of the data. On the contrary, nonreducible touch points are not stable under perturbations. We show that under some reasonable conditions, either a boundary arc or a second touch point may appear. Those results allow us to design an homotopy algorithm which automatically detects the structure of the trajectory and initializes the shooting parameters associated with boundary arcs and touch points.
Constraints to solve parallelogram grid problems in 2D non separable linear canonical transform
Zhao, Liang; Healy, John J.; Muniraj, Inbarasan; Cui, Xiao-Guang; Malallah, Ra'ed; Ryle, James P.; Sheridan, John T.
2017-05-01
The 2D non-separable linear canonical transform (2D-NS-LCT) can model a range of various paraxial optical systems. Digital algorithms to evaluate the 2D-NS-LCTs are important in modeling the light field propagations and also of interest in many digital signal processing applications. In [Zhao 14] we have reported that a given 2D input image with rectangular shape/boundary, in general, results in a parallelogram output sampling grid (generally in an affine coordinates rather than in a Cartesian coordinates) thus limiting the further calculations, e.g. inverse transform. One possible solution is to use the interpolation techniques; however, it reduces the speed and accuracy of the numerical approximations. To alleviate this problem, in this paper, some constraints are derived under which the output samples are located in the Cartesian coordinates. Therefore, no interpolation operation is required and thus the calculation error can be significantly eliminated.
A problem-based approach to elastic wave propagation: the role of constraints
International Nuclear Information System (INIS)
Fazio, Claudio; Guastella, Ivan; Tarantino, Giovanni
2009-01-01
A problem-based approach to the teaching of mechanical wave propagation, focused on observation and measurement of wave properties in solids and on modelling of these properties, is presented. In particular, some experimental results, originally aimed at measuring the propagation speed of sound waves in metallic rods, are used in order to deepen the role of constraints in mechanical wave propagation. Interpretative models of the results obtained in the laboratory are built and implemented by using a well-known simulation environment. The simulation results are, then, compared with experimental data. The approach has been developed and experimented in the context of a workshop on mechanical wave propagation of the two-year Graduate Program for Physics Teacher Education at University of Palermo.
Bayón, L.; Grau, J. M.; Ruiz, M. M.; Suárez, P. M.
2012-12-01
One of the most well-known problems in the field of Microeconomics is the Firm's Cost-Minimization Problem. In this paper we establish the analytical expression for the cost function using the Cobb-Douglas model and considering maximum constraints for the inputs. Moreover we prove that it belongs to the class C1.
Giesy, D. P.
1978-01-01
A technique is presented for the calculation of Pareto-optimal solutions to a multiple-objective constrained optimization problem by solving a series of single-objective problems. Threshold-of-acceptability constraints are placed on the objective functions at each stage to both limit the area of search and to mathematically guarantee convergence to a Pareto optimum.
Bouchard , Bruno; Dang , Ngoc Minh
2013-01-01
International audience; We consider a singular with state constraints version of the stochastic target problems studied in Soner and Touzi (2002) and more recently Bouchard, Elie and Touzi (2008), among others. This provides a general framework for the pricing of contingent claims under risk constraints. Our extended version perfectly suits to market models with proportional transaction costs and to order book liquidation issues. Our main result is a PDE characterization of the associated pri...
The MarCon Algorithm: A Systematic Market Approach to Distributed Constraint Problems
National Research Council Canada - National Science Library
Parunak, H. Van Dyke
1998-01-01
.... Each variable integrates this information from the constraints interested in it and provides feedback that enables the constraints to shrink their sets of assignments until they converge on a solution...
DEFF Research Database (Denmark)
Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca
2010-01-01
We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...... results show that constraint differentiation substantially reduces search and considerably improves the performance of OFMC, enabling its application to a wider class of problems....
Directory of Open Access Journals (Sweden)
T. S. Kasatkina
2015-01-01
Full Text Available Terminal control problem with fixed finite time for the second order affine systems with state constraints is considered. A solution of such terminal problem is suggested for the systems with scalar control of regular canonical form.In this article it is shown that the initial terminal problem is equivalent to the problem of auxiliary function search. This function should satisfy some conditions. Such function design consists of two stages. The first stage includes search of function which corresponds the solution of the terminal control problem without state constraints. This function is designed as polynom of the fifth power which depends on time variable. Coefficients of the polynom are defined by boundary conditions. The second stage includes modification of designed function if corresponding to that function trajectory is not satisfied constraints. Modification process is realized by adding to the current function supplementary polynom. Influence of that polynom handles by variation of a parameter value. Modification process can include a few iterations. After process termination continuous control is found. This control is the solution of the initial terminal prUsing presented scheme the terminal control problem for system, which describes oscillations of the mathematical pendulum, is solved. This approach can be used for the solution of terminal control problems with state constraints for affine systems with multi-dimensional control.
Xiang, Wei; Yin, Jiao; Lim, Gino
2015-02-01
Operating room (OR) surgery scheduling determines the individual surgery's operation start time and assigns the required resources to each surgery over a schedule period, considering several constraints related to a complete surgery flow and the multiple resources involved. This task plays a decisive role in providing timely treatments for the patients while balancing hospital resource utilization. The originality of the present study is to integrate the surgery scheduling problem with real-life nurse roster constraints such as their role, specialty, qualification and availability. This article proposes a mathematical model and an ant colony optimization (ACO) approach to efficiently solve such surgery scheduling problems. A modified ACO algorithm with a two-level ant graph model is developed to solve such combinatorial optimization problems because of its computational complexity. The outer ant graph represents surgeries, while the inner graph is a dynamic resource graph. Three types of pheromones, i.e. sequence-related, surgery-related, and resource-related pheromone, fitting for a two-level model are defined. The iteration-best and feasible update strategy and local pheromone update rules are adopted to emphasize the information related to the good solution in makespan, and the balanced utilization of resources as well. The performance of the proposed ACO algorithm is then evaluated using the test cases from (1) the published literature data with complete nurse roster constraints, and 2) the real data collected from a hospital in China. The scheduling results using the proposed ACO approach are compared with the test case from both the literature and the real life hospital scheduling. Comparison results with the literature shows that the proposed ACO approach has (1) an 1.5-h reduction in end time; (2) a reduction in variation of resources' working time, i.e. 25% for ORs, 50% for nurses in shift 1 and 86% for nurses in shift 2; (3) an 0.25h reduction in
Directory of Open Access Journals (Sweden)
V R Hemanth Kumar
2014-01-01
Full Text Available Background and Aims: Subarachnoid block is one of the common modes of anaesthesia opted for emergency caesarean section, if the maternal and foetal conditions are favourable. Various factors influence the quality of care administered during the procedure. This questionnaire based study was undertaken to look for self-expressed problems in peri-operative period in patients undergoing emergency caesarean surgery under subarachnoid block. Methods: All the parturients who underwent emergency caesarean section under subarachnoid block during 6 months period were distributed a questionnaire in post-operative period. They were encouraged to fill and return the form within 15 days. Patient satisfaction and the self-expressed problems were analysed at the end of 6 months. Results: One hundred and seventy five out of 220 parturients responded. 58.3% of them said that they were explained about the anaesthesia prior to surgery and 85.3% overall remained anxious. With people around them, 93.1% of them felt comfortable and 91.4% expressed that they were made comfortable inside the theatre. The self-expressed problems were shivering (43.4%, breathlessness (21.7%, pain (20%, post-operative headache (15.4% and backache (19.4%. Parturients who heard their babies cry was 85.1%. After their babies were shown after delivery, 77.1% mothers slept well; 86.9% fed their babies within 4 h of delivery. Conclusion: Pre-operative communication in emergency caesarean section by health personnel did not reduce the anxiety level, which shows that communication was ineffective. Intra-operative psychological support like making the patient comfortable, showing baby to mother and early breast feeding improve bonding between child and mother and essentially contribute to patient satisfaction.
Numerical Solution of Mixed Problems of the Theory of Elasticity with One-Sided Constraints
Directory of Open Access Journals (Sweden)
I. V. Stankevich
2017-01-01
Full Text Available The paper deals with the application features of the finite element technologies to solve the problems of elasticity with one-sided constraints. On the one hand, the area of this study is determined by the fact that many critical parts and assemblies of mechanical and power engineering constructions have a significant contact within some given surface. To assess the strength and the life of these parts and assemblies, reliable stress-strain state data are demandable. Data on the stress-strain state can be obtained using the contemporary mathematical modeling means, e.g., finite element technology.To solve the problems of the theory of elasticity with one-sided constraints, a method of finite elements in a traditional classical form can be used, but it is necessary to consider some of its shortcomings. The most significant one is an approximation of the tensile stress and strain, as well as a considerably lower order of convergence of the approximation for stresses and strains as compared to displacements. Improving the accuracy through increasing a density of the finite element models and/or the transition to more complex approximations is not always optimal, because increasing a dimension of the discrete problem leads to a significant computational cost and demand for expensive computing resources.One of the alternatives in numerical analysis of contact problems of the elasticity theory is to use the mixed variational formulations of the finite element method in which stresses and/or strains appear in the resolving equations along with displacements as equal unknown. A major positive factor when using the mixed formulations of the finite element method is reduction of the approximation error of stress and strain, which leads to a more accurate assessment of the stress-strain state in comparison with the classical approach of the finite element method in the form of the method of displacements.Besides, mixed schemes of the finite element method
Job Satisfaction And Family Happiness : The Part-Time Work Problem
Booth, A.L.; van Ours, J.C.
2007-01-01
Using fixed effects ordered logit estimation, we investigate the relationship between part-time work and working hours satisfaction; job satisfaction; and life satisfaction. We account for interdependence within the family using data on partnered men and women from the British Household Panel
Poot, Antonius J; den Elzen, Wendy P J; Blom, Jeanet W; Gussekloo, Jacobijn
2014-01-01
Satisfaction is widely used to evaluate and direct delivery of medical care; a complicated relationship exists between patient satisfaction, morbidity and age. This study investigates the relationships between complexity of health problems and level of patient satisfaction of older persons with their general practitioner (GP) and practice. This study is embedded in the ISCOPE (Integrated Systematic Care for Older Persons) study. Enlisted patients aged ≥75 years from 59 practices received a written questionnaire to screen for complex health problems (somatic, functional, psychological and social). For 2664 randomly chosen respondents (median age 82 years; 68% female) information was collected on level of satisfaction (satisfied, neutral, dissatisfied) with their GP and general practice, and demographic and clinical characteristics including complexity of health problems. Of all participants, 4% was dissatisfied with their GP care, 59% neutral and 37% satisfied. Between these three categories no differences were observed in age, gender, country of birth or education level. The percentage of participants dissatisfied with their GP care increased from 0.4% in those with 0 problem domains to 8% in those with 4 domains, i.e. having complex health problems (ppatient characteristic influencing the perception of care, or whether the care is unable to handle the demands of these patients. Prospective studies are needed to investigate the causal associations between care organization, patient characteristics, indicators of quality, and patient perceptions.
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2014-01-01
Full Text Available We introduce and analyze one iterative algorithm by hybrid shrinking projection method for finding a solution of the minimization problem for a convex and continuously Fréchet differentiable functional, with constraints of several problems: finitely many generalized mixed equilibrium problems, finitely many variational inequalities, the general system of variational inequalities and the fixed point problem of an asymptotically strict pseudocontractive mapping in the intermediate sense in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another iterative algorithm by hybrid shrinking projection method for finding a fixed point of infinitely many nonexpansive mappings with the same constraints, and derive its strong convergence under mild assumptions.
Directory of Open Access Journals (Sweden)
Serkan Altuntaş
2010-01-01
Full Text Available Occasionally certain tasks in an assembly line balancing problem are required to be kept together due to some specific reasons. These tasks are attained to the same work stations. Such problems are called as 'Assembly Line Balancing Problem with Task Related Constraints (ALBTRC'. Certain situations like awkward product construction, simultaneous operations or specific requirements leading to zoning and positional constraints like utilization of common resources as tools, jigs and fixtures are implemented thanks to these supplementary constraints. Additionally, materials handling and tooling costs, distances, set-up and lead times are also reduced. Literature on ALBTRC seems quite rare compared to Classical Line Balancing papers, although ALBTRC is one of the common real life balancing problems. This study aimed to develop and implement a novel line balancing method for a manufacturing concern where known methods are impractical to employ due to some specific positional constraints. 'Largest Candidate Method' known as a simple but effective tool is modified for this purpose first. Then a thorough 'method and time study' is conducted to get the necessary data to utilize that method. As a result, more efficient alternatives are generated and presented to decision maker.
Tarim, S.A.; Ozen, U.; Dogru, M.K.; Rossi, R.
2011-01-01
We provide an efficient computational approach to solve the mixed integer programming (MIP) model developed by Tarim and Kingsman [8] for solving a stochastic lot-sizing problem with service level constraints under the static–dynamic uncertainty strategy. The effectiveness of the proposed method
Cardinality reasoning for bin-packing constraint : Application to a tank allocation problem
Schaus, Pierre; Régin, Jean Charles; Van Schaeren, Rowan; Dullaert, Wout; Raa, Birger
2012-01-01
Flow reasoning has been successfully used in CP for more than a decade. It was originally introduced by Régin in the well-known Alldifferent and Global Cardinality Constraint (GCC) available in most of the CP solvers. The BinPacking constraint was introduced by Shaw and mainly uses an independent
Montanari, Giulia; Di Donato, Nadine; Benfenati, Arianna; Giovanardi, Giulia; Zannoni, Letizia; Vicenzi, Claudia; Solfrini, Serena; Mignemi, Giuseppe; Villa, Gioia; Mabrouk, Mohamed; Schioppa, Claudio; Venturoli, Stefano; Seracchioli, Renato
2013-06-01
Endometriosis is a chronic and progressive condition of women of reproductive age. It is strongly associated with a significant reduction of quality of life (QOL) and sexual function. This study aims to objectively evaluate sexual function in women with deep infiltrating endometriosis (DIE) and to study the impact of endometriosis symptoms and type of lesion on patient's sexual function. This is a cross-sectional study in a tertiary care university hospital. It included 182 patients with preoperative clinical and ultrasound diagnosis of DIE who were referred to our center from 2008 to 2011. A sexual activity questionnaire, the Sexual Health Outcomes in Women Questionnaire (SHOW-Q) was used to collect data pertaining to satisfaction, orgasm, desire, and pelvic problem interference with sex. Short Form 36 (SF-36) was used to evaluate QOL. Demographic and clinical characteristics were assessed: age, body mass index, parity, ethnicity, postsecondary education, employment, smoking, history of surgical treatment, and hormonal contraception. Patients were asked about pain symptoms (dysmenorrhea, dyspareunia, dyschezia, chronic pelvic pain, and dysuria) using a visual analog scale. The mean values obtained on the different scales of the SHOW-Q showed poor sexual function (mean SHOW-Q total score 56.38 ± 22.74). Satisfaction was the dimension most affected (mean satisfaction score 55.66 ± 34.55), followed by orgasm (mean orgasm score 56.90 ± 33.77). We found a significant correlation between the SF-36 scores and the SHOW-Q scores (P < 0.0001). Sexual dysfunction and deterioration of QOL seem to be correlated. Analyzing the impact of symptoms and lesions on sexual function, we found that dyspareunia and vaginal DIE nodules significantly affect sexual activity (P < 0.05). The results of this study demonstrated that women with DIE have a sexual function impairment, correlated with the overall well-being decrease. Moreover, the presence of dyspareunia and vaginal
Sisask, Merike; Värnik, Peeter; Värnik, Airi; Apter, Alan; Balazs, Judit; Balint, Maria; Bobes, Julio; Brunner, Romuald; Corcoran, Paul; Cosman, Doina; Feldman, Dana; Haring, Christian; Kahn, Jean-Pierre; Poštuvan, Vita; Tubiana, Alexandra; Sarchiapone, Marco; Wasserman, Camilla; Carli, Vladimir; Hoven, Christina W.; Wasserman, Danuta
2014-01-01
Objective: In support of a whole-school approach to mental health promotion, this study was conducted to find out whether and how significantly teachers' satisfaction with school and their subjective psychological well-being are related to the belief that they can help pupils with mental health problems. Design: Cross-sectional data were collected…
Directory of Open Access Journals (Sweden)
Antonius J Poot
Full Text Available BACKGROUND: Satisfaction is widely used to evaluate and direct delivery of medical care; a complicated relationship exists between patient satisfaction, morbidity and age. This study investigates the relationships between complexity of health problems and level of patient satisfaction of older persons with their general practitioner (GP and practice. METHODS AND FINDINGS: This study is embedded in the ISCOPE (Integrated Systematic Care for Older Persons study. Enlisted patients aged ≥75 years from 59 practices received a written questionnaire to screen for complex health problems (somatic, functional, psychological and social. For 2664 randomly chosen respondents (median age 82 years; 68% female information was collected on level of satisfaction (satisfied, neutral, dissatisfied with their GP and general practice, and demographic and clinical characteristics including complexity of health problems. Of all participants, 4% was dissatisfied with their GP care, 59% neutral and 37% satisfied. Between these three categories no differences were observed in age, gender, country of birth or education level. The percentage of participants dissatisfied with their GP care increased from 0.4% in those with 0 problem domains to 8% in those with 4 domains, i.e. having complex health problems (p<0.001. Per additional health domain with problems, the risk of being dissatisfied increased 1.7 times (95% CI 1.4-2.14; p<0.001. This was independent of age, gender, and demographic and clinical parameters (adjusted OR 1.4, 95% CI 1.1-1.8; p = 0.021. CONCLUSION: In older persons, dissatisfaction with general practice is strongly correlated with rising complexity of health problems, independent of age, demographic and clinical parameters. It remains unclear whether complexity of health problems is a patient characteristic influencing the perception of care, or whether the care is unable to handle the demands of these patients. Prospective studies are needed to
Directory of Open Access Journals (Sweden)
Hamidreza Haddad
2012-04-01
Full Text Available This paper tackles the single machine scheduling problem with dependent setup time and precedence constraints. The primary objective of this paper is minimization of total weighted tardiness. Since the complexity of the resulted problem is NP-hard we use metaheuristics method to solve the resulted model. The proposed model of this paper uses genetic algorithm to solve the problem in reasonable amount of time. Because of high sensitivity of GA to its initial values of parameters, a Taguchi approach is presented to calibrate its parameters. Computational experiments validate the effectiveness and capability of proposed method.
Directory of Open Access Journals (Sweden)
Alexandr Victorovich Budylskiy
2014-06-01
Full Text Available This article considers the multicriteria optimization approach using the modified genetic algorithm to solve the project-scheduling problem under duration and cost constraints. The work contains the list of choices for solving this problem. The multicriteria optimization approach is justified here. The study describes the Pareto principles, which are used in the modified genetic algorithm. We identify the mathematical model of the project-scheduling problem. We introduced the modified genetic algorithm, the ranking strategies, the elitism approaches. The article includes the example.
DEFF Research Database (Denmark)
Pour, Shahrzad M.; Drake, John H.; Ejlertsen, Lena Secher
2017-01-01
A railway signaling system is a complex and interdependent system which should ensure the safe operation of trains. We introduce and address a mixed integer optimisation model for the preventive signal maintenance crew scheduling problem in the Danish railway system. The problem contains many...... to feed as ‘warm start’ solutions to a Mixed Integer Programming (MIP) solver for further optimisation. We apply the CP/MIP framework to a section of the Danish rail network and benchmark our results against both direct application of a MIP solver and modelling the problem as a Constraint Optimisation...
Directory of Open Access Journals (Sweden)
Azza Hassan Amer
2017-12-01
Full Text Available Geometric programming problem is a powerful tool for solving some special type nonlinear programming problems. In the last few years we have seen a very rapid development on solving multiobjective geometric programming problem. A few mathematical programming methods namely fuzzy programming, goal programming and weighting methods have been applied in the recent past to find the compromise solution. In this paper, -constraint method has been applied in bi-level multiobjective geometric programming problem to find the Pareto optimal solution at each level. The equivalent mathematical programming problems are formulated to find their corresponding value of the objective function based on the duality theorem at eash level. Here, we have developed a new algorithm for fuzzy programming technique to solve bi-level multiobjective geometric programming problems to find an optimal compromise solution. Finally the solution procedure of the fuzzy technique is illustrated by a numerical example
Directory of Open Access Journals (Sweden)
Daniel Tan Lei Shek
2013-08-01
Full Text Available This study investigated whether Chinese adolescents living in intact and non-intact families differed in their positive development, life satisfaction, and risk behavior. A total of 3,328 Secondary 1 students responded to measures of positive youth development (such as resilience and psychosocial competencies, life satisfaction, and risk behavior (substance abuse, delinquency, Internet addiction, consumption of pornographic materials, self-harm, and behavioral intention to engage in problem behavior. Findings revealed that adolescents growing up in intact families reported higher levels of positive developmental outcomes and life satisfaction as compared with adolescents from non-intact families. Adolescents in non-intact families also reported higher levels of risk behaviors than those growing up in intact families.
Chilkoti, Geetanjali; Mohta, Medha; Wadhwa, Rachna; Saxena, Ashok Kumar; Sharma, Chhavi Sarabpreet; Shankar, Neelima
2016-11-01
Students are exposed to basic life support (BLS) and advanced cardiac life support (ACLS) training in the first semester in some medical colleges. The aim of this study was to compare students' satisfaction between lecture-based traditional method and hybrid problem-based learning (PBL) in BLS/ACLS teaching to undergraduate medical students. We conducted a questionnaire-based, cross-sectional survey among 118 1 st -year medical students from a university medical college in the city of New Delhi, India. We aimed to assess the students' satisfaction between lecture-based and hybrid-PBL method in BLS/ACLS teaching. Likert 5-point scale was used to assess students' satisfaction levels between the two teaching methods. Data were collected and scores regarding the students' satisfaction levels between these two teaching methods were analysed using a two-sided paired t -test. Most students preferred hybrid-PBL format over traditional lecture-based method in the following four aspects; learning and understanding, interest and motivation, training of personal abilities and being confident and satisfied with the teaching method ( P < 0.05). Implementation of hybrid-PBL format along with the lecture-based method in BLS/ACLS teaching provided high satisfaction among undergraduate medical students.
The problem of bias when nursing facility staff administer customer satisfaction surveys.
Hodlewsky, R Tamara; Decker, Frederic H
2002-10-01
Customer satisfaction instruments are being used with increasing frequency to assess and monitor residents' assessments of quality of care in nursing facilities. There is no standard protocol, however, for how or by whom the instruments should be administered when anonymous, written responses are not feasible. Researchers often use outside interviewers to assess satisfaction, but cost considerations may limit the extent to which facilities are able to hire outside interviewers on a regular basis. This study was designed to investigate the existence and extent of any bias caused by staff administering customer satisfaction surveys. Customer satisfaction data were collected in 1998 from 265 residents in 21 nursing facilities in North Dakota. Half the residents in each facility were interviewed by staff members and the other half by outside consultants; scores were compared by interviewer type. In addition to a tabulation of raw scores, ordinary least-squares analysis with facility fixed effects was used to control for resident characteristics and unmeasured facility-level factors that could influence scores. Significant positive bias was found when staff members interviewed residents. The bias was not limited to questions directly affecting staff responsibilities but applied across all types of issues. The bias was robust under varying constructions of satisfaction and dissatisfaction. A uniform method of survey administration appears to be important if satisfaction data are to be used to compare facilities. Bias is an important factor that should be considered and weighed against the costs of obtaining outside interviewers when assessing customer satisfaction among long term care residents.
Baniamerian, Ali; Bashiri, Mahdi; Zabihi, Fahime
2018-03-01
Cross-docking is a new warehousing policy in logistics which is widely used all over the world and attracts many researchers attention to study about in last decade. In the literature, economic aspects has been often studied, while one of the most significant factors for being successful in the competitive global market is improving quality of customer servicing and focusing on customer satisfaction. In this paper, we introduce a vehicle routing and scheduling problem with cross-docking and time windows in a three-echelon supply chain that considers customer satisfaction. A set of homogeneous vehicles collect products from suppliers and after consolidation process in the cross-dock, immediately deliver them to customers. A mixed integer linear programming model is presented for this problem to minimize transportation cost and early/tardy deliveries with scheduling of inbound and outbound vehicles to increase customer satisfaction. A two phase genetic algorithm (GA) is developed for the problem. For investigating the performance of the algorithm, it was compared with exact and lower bound solutions in small and large-size instances, respectively. Results show that there are at least 86.6% customer satisfaction by the proposed method, whereas customer satisfaction in the classical model is at most 33.3%. Numerical examples results show that the proposed two phase algorithm could achieve optimal solutions in small-size instances. Also in large-size instances, the proposed two phase algorithm could achieve better solutions with less gap from the lower bound in less computational time in comparison with the classic GA.
Tavakkoli-Moghaddam, Reza; Alinaghian, Mehdi; Salamat-Bakhsh, Alireza; Norouzi, Narges
2012-05-01
A vehicle routing problem is a significant problem that has attracted great attention from researchers in recent years. The main objectives of the vehicle routing problem are to minimize the traveled distance, total traveling time, number of vehicles and cost function of transportation. Reducing these variables leads to decreasing the total cost and increasing the driver's satisfaction level. On the other hand, this satisfaction, which will decrease by increasing the service time, is considered as an important logistic problem for a company. The stochastic time dominated by a probability variable leads to variation of the service time, while it is ignored in classical routing problems. This paper investigates the problem of the increasing service time by using the stochastic time for each tour such that the total traveling time of the vehicles is limited to a specific limit based on a defined probability. Since exact solutions of the vehicle routing problem that belong to the category of NP-hard problems are not practical in a large scale, a hybrid algorithm based on simulated annealing with genetic operators was proposed to obtain an efficient solution with reasonable computational cost and time. Finally, for some small cases, the related results of the proposed algorithm were compared with results obtained by the Lingo 8 software. The obtained results indicate the efficiency of the proposed hybrid simulated annealing algorithm.
Directory of Open Access Journals (Sweden)
Hinz Andreas
2009-03-01
Full Text Available Abstract Background Parental rearing behavior is a significant etiological factor for the vulnerability of psychopathology and has been an issue of clinical research for a long time. For this scope instruments are important who asses economically recalled parental rearing behavior in a clinical practice. Therefore, a short German instrument for the assessment of the recalled parental rearing behavior Fragebogen zum erinnerten elterlichen Erziehungsverhalten (FEE was psychometrically evaluated [Recalled Parental Rearing Behavior]. Methods This questionnaire was evaluated in a representative population sample (N = 2.948 in Germany which included 44.2% male and 55.8% female persons with a mean age of M = 47.35 (SD = 17.10, range = 18–92. For the content evaluation of the FEE the Life Satisfaction Questionnaire (FLZ and the Inventory of Interpersonal Problems (IIP was filled out by the participants. Results The FEE scales yielded a good to satisfactory internal consistency and split-half reliability. Its three factors (rejection/punishment, emotional warmth, control/overprotection correlated positively with most of the areas of life satisfaction. Furthermore, positive associations between interpersonal problems and parental rejection and control could be identified. Conclusion The FEE is a short, reliable and valid instrument that can be applied in the clinical practice. In addition, the data proved an association between recalled parental rearing behavior, life satisfaction and interpersonal problems conform to the literature. Finally, specific problems with the retrospective assessment of parental rearing behavior were addressed as well.
Directory of Open Access Journals (Sweden)
Nelson Maculan
2003-01-01
Full Text Available We present integer linear models with a polynomial number of variables and constraints for combinatorial optimization problems in graphs: optimum elementary cycles, optimum elementary paths and optimum tree problems.Apresentamos modelos lineares inteiros com um número polinomial de variáveis e restrições para problemas de otimização combinatória em grafos: ciclos elementares ótimos, caminhos elementares ótimos e problemas em árvores ótimas.
DEFF Research Database (Denmark)
Hansen, Anders Dohn; Kolind, Esben; Clausen, Jens
2009-01-01
In this paper, we consider the Manpower Allocation Problem with Time Windows, Job-Teaming Constraints and a limited number of teams (m-MAPTWTC). Given a set of teams and a set of tasks, the problem is to assign to each team a sequential order of tasks to maximize the total number of assigned tasks....... Both teams and tasks may be restricted by time windows outside which operation is not possible. Some tasks require cooperation between teams, and all teams cooperating must initiate execution simultaneously. We present an IP-model for the problem, which is decomposed using Dantzig-Wolfe decomposition....... The problem is solved by column generation in a Branch-and-Price framework. Simultaneous execution of tasks is enforced by the branching scheme. To test the efficiency of the proposed algorithm, 12 realistic test instances are introduced. The algorithm is able to find the optimal solution in 11 of the test...
DEFF Research Database (Denmark)
Hansen, Anders Dohn; Kolind, Esben; Clausen, Jens
In this paper, we consider the Manpower Allocation Problem with Time Windows, Job-Teaming Constraints and a limited number of teams (m-MAPTWTC). Given a set of teams and a set of tasks, the problem is to assign to each team a sequential order of tasks to maximize the total number of assigned tasks....... Both teams and tasks may be restricted by time windows outside which operation is not possible. Some tasks require cooperation between teams, and all teams cooperating must initiate execution simultaneously. We present an IP-model for the problem, which is decomposed using Dantzig-Wolfe decomposition....... The problem is solved by column generation in a Branch-and-Price framework. Simultaneous execution of tasks is enforced by the branching scheme. To test the efficiency of the proposed algorithm, 12 realistic test instances are introduced. The algorithm is able to find the optimal solution in 11 of the test...
A constraint programming solution for the military unit path finding problem
CSIR Research Space (South Africa)
Leenen, L
2012-01-01
Full Text Available In this chapter the authors present an algorithm to solve the Dynamic Military Unit Path Finding Problem (DMUPFP) which is based on Stentz’s well-known D* algorithm to solve dynamic path finding problems. The Military Unit Path Finding Problem...
Optimality conditions for the numerical solution of optimization problems with PDE constraints :
Energy Technology Data Exchange (ETDEWEB)
Aguilo Valentin, Miguel Alejandro; Ridzal, Denis
2014-03-01
A theoretical framework for the numerical solution of partial di erential equation (PDE) constrained optimization problems is presented in this report. This theoretical framework embodies the fundamental infrastructure required to e ciently implement and solve this class of problems. Detail derivations of the optimality conditions required to accurately solve several parameter identi cation and optimal control problems are also provided in this report. This will allow the reader to further understand how the theoretical abstraction presented in this report translates to the application.
Directory of Open Access Journals (Sweden)
Zhifeng Dai
2014-01-01
Full Text Available Combining the Rosen gradient projection method with the two-term Polak-Ribière-Polyak (PRP conjugate gradient method, we propose a two-term Polak-Ribière-Polyak (PRP conjugate gradient projection method for solving linear equality constraints optimization problems. The proposed method possesses some attractive properties: (1 search direction generated by the proposed method is a feasible descent direction; consequently the generated iterates are feasible points; (2 the sequences of function are decreasing. Under some mild conditions, we show that it is globally convergent with Armijio-type line search. Preliminary numerical results show that the proposed method is promising.
Suldo, Shannon M.; Huebner, E. Scott
2004-01-01
Research examining environmental factors associated with adolescents' life satisfaction (LS) has revealed that familial variables (e.g., parent-child conflict, family structure) are crucial correlates. The purpose of the current study was to identify particular dimensions of authoritative parenting (strictness-supervision, social…
Complexity of the positive semidefinite matrix completion problem with a rank constraint
Nagy, M.; Laurent, M.; Varvitsiotis, A.; Bezdek, K.; Deza, A.; Ye, Y.
2013-01-01
We consider the decision problem asking whether a partial rational symmetric matrix with an all-ones diagonal can be completed to a full positive semidefinite matrix of rank at most k. We show that this problem is NP-hard for any fixed integer k ≥ 2. In other words, for k ≥ 2, it is NP-hard to test
Complexity of the positive semidefinite matrix completion problem with a rank constraint.
M. Eisenberg-Nagy (Marianna); M. Laurent (Monique); A. Varvitsiotis (Antonios); K. Bezdek; A. Deza; Y. Ye
2013-01-01
htmlabstractWe consider the decision problem asking whether a partial rational symmetric matrix with an all-ones diagonal can be completed to a full positive semidefinite matrix of rank at most k. We show that this problem is NP-hard for any fixed integer k ≥ 2. Equivalently, for k ≥ 2, it is
Complexity of the positive semidefinite matrix completion problem with a rank constraint.
M. Eisenberg-Nagy (Marianna); M. Laurent (Monique); A. Varvitsiotis (Antonios)
2012-01-01
htmlabstractWe consider the decision problem asking whether a partial rational symmetric matrix with an all-ones diagonal can be completed to a full positive semidefinite matrix of rank at most k. We show that this problem is NP-hard for any fixed integer k ≥ 2. Equivalently, for k ≥ 2, it is
The regular indefinite linear-quadratic problem with linear endpoint constraints
Soethoudt, J.M.; Trentelman, H.L.
1989-01-01
This paper deals with the infinite horizon linear-quadratic problem with indefinite cost. Given a linear system, a quadratic cost functional and a subspace of the state space, we consider the problem of minimizing the cost functional over all inputs for which the state trajectory converges to that
A Smooth Newton Method for Nonlinear Programming Problems with Inequality Constraints
Directory of Open Access Journals (Sweden)
Vasile Moraru
2012-02-01
Full Text Available The paper presents a reformulation of the Karush-Kuhn-Tucker (KKT system associated nonlinear programming problem into an equivalent system of smooth equations. Classical Newton method is applied to solve the system of equations. The superlinear convergence of the primal sequence, generated by proposed method, is proved. The preliminary numerical results with a problems test set are presented.
Goodrich, Charles H.; Kurien, James; Clancy, Daniel (Technical Monitor)
2001-01-01
We present some diagnosis and control problems that are difficult to solve with discrete or purely qualitative techniques. We analyze the nature of the problems, classify them and explain why they are frequently encountered in systems with closed loop control. This paper illustrates the problem with several examples drawn from industrial and aerospace applications and presents detailed information on one important application: In-Situ Resource Utilization (ISRU) on Mars. The model for an ISRU plant is analyzed showing where qualitative techniques are inadequate to identify certain failure modes and to maintain control of the system in degraded environments. We show why the solution to the problem will result in significantly more robust and reliable control systems. Finally, we illustrate requirements for a solution to the problem by means of examples.
The robust min-max newsvendor problem with balking under a service level constraint
Directory of Open Access Journals (Sweden)
Taesu Cheong
2013-11-01
Full Text Available In this paper we study an extension of a classic newsvendor model with balking under a service-level constraint. We also relax the assumption that the demand distribution is fully available to a decision-maker; we assume that only the mean and variance of the demand distribution are known, and discuss the procedure for determining the optimal order quantity for the concomitant model. We further extend our base model to two different cases: (i when the fixed ordering cost is included, and (ii when yield is uncertain. We illustrate the solution procedures for each case with numerical examples. Moreover, we discuss the performance and robustness of the approach through randomly generated test instances, and perform a numerical sensitivity analysis to evaluate the impact of the changes of a targeted fill-rate and variances of a demand distribution.
Directory of Open Access Journals (Sweden)
Salvator Abreu
2009-10-01
Full Text Available We explore the use of the Cell Broadband Engine (Cell/BE for short for combinatorial optimization applications: we present a parallel version of a constraint-based local search algorithm that has been implemented on a multiprocessor BladeCenter machine with twin Cell/BE processors (total of 16 SPUs per blade. This algorithm was chosen because it fits very well the Cell/BE architecture and requires neither shared memory nor communication between processors, while retaining a compact memory footprint. We study the performance on several large optimization benchmarks and show that this achieves mostly linear time speedups, even sometimes super-linear. This is possible because the parallel implementation might explore simultaneously different parts of the search space and therefore converge faster towards the best sub-space and thus towards a solution. Besides getting speedups, the resulting times exhibit a much smaller variance, which benefits applications where a timely reply is critical.
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M. Abdul-Niby
2016-04-01
Full Text Available The Traveling Salesman Problem (TSP is an integer programming problem that falls into the category of NP-Hard problems. As the problem become larger, there is no guarantee that optimal tours will be found within reasonable computation time. Heuristics techniques, like genetic algorithm and simulating annealing, can solve TSP instances with different levels of accuracy. Choosing which algorithm to use in order to get a best solution is still considered as a hard choice. This paper suggests domain reduction as a tool to be combined with any meta-heuristic so that the obtained results will be almost the same. The hybrid approach of combining domain reduction with any meta-heuristic encountered the challenge of choosing an algorithm that matches the TSP instance in order to get the best results.
Institute of Scientific and Technical Information of China (English)
LIU Xiaoping; HE Honglin; XU Benzhu
2012-01-01
Engineering-oriented constraint of harness technology has much information and project information presents progressive changes along with the design. Therefore, how to handle conflict resolution quickly is a problem to be solved. Process model of con- flict detection is put forward according to characteristics of harness technology design engineering-oriented constraint, and then two problems of how to conduct conflict positioning and judgment of constraint rules are introduced in this paper. Afterwards in this pa- per, constraint information directed acyclic graph is established by classified project constraint information to solve the conflict posi- tioning problem; solution of constraint satisfaction problem is applied to realize judgment problem of constraint rules. Finally, exam- ple is used to analyze the method in this paper to further verify the correctness and effectiveness of this method.
Fuzzy solution of the linear programming problem with interval coefficients in the constraints
Dorota Kuchta
2005-01-01
A fuzzy concept of solving the linear programming problem with interval coefficients is proposed. For each optimism level of the decision maker (where the optimism concerns the certainty that no errors have been committed in the estimation of the interval coefficients and the belief that optimistic realisations of the interval coefficients will occur) another interval solution of the problem will be generated and the decision maker will be able to choose the final solution having a complete v...
DEFF Research Database (Denmark)
Iris, Cagatay; Røpke, Stefan; Pacino, Dario
,74% 63,0 X 7,97% 600* 68,0 67,9 0,19% 600 8 56,1 56,1 0,00% 51,3 X 9,42% 600* 56,1 55,8 0,59% 600* 9 75,1 75,0 0,13% 74,9 X 0,33% 600* 75,1 75,0 0,15% 600* BACAP can also be formulated as Generalized Set Partitioning Problem (GSPP). The model is an extension of the BAP formulation in [2] where we add new...... problem (BAP) and the quay crane assignment problem (QCAP). Such integrated problem is known in the literature ([1]) as the Berth Allocation and Crane Assignment Problem (BACAP). The state-of-the-art [1] models this problem using two decision variables X_ij and Y_ij, representing respectively the partial...... since start-time variables S_i are integrated into objective function. Inequality (1) is based on the following two observations. First, if vessel i berths before vessel j (X_ij=1), then the start time of vessel j (Sj) should be larger than the start time of vessel i plus its minimum expected processing...
Fuzzy Constraint-Based Agent Negotiation
Institute of Scientific and Technical Information of China (English)
Menq-Wen Lin; K. Robert Lai; Ting-Jung Yu
2005-01-01
Conflicts between two or more parties arise for various reasons and perspectives. Thus, resolution of conflicts frequently relies on some form of negotiation. This paper presents a general problem-solving framework for modeling multi-issue multilateral negotiation using fuzzy constraints. Agent negotiation is formulated as a distributed fuzzy constraint satisfaction problem (DFCSP). Fuzzy constrains are thus used to naturally represent each agent's desires involving imprecision and human conceptualization, particularly when lexical imprecision and subjective matters are concerned. On the other hand, based on fuzzy constraint-based problem-solving, our approach enables an agent not only to systematically relax fuzzy constraints to generate a proposal, but also to employ fuzzy similarity to select the alternative that is subject to its acceptability by the opponents. This task of problem-solving is to reach an agreement that benefits all agents with a high satisfaction degree of fuzzy constraints, and move towards the deal more quickly since their search focuses only on the feasible solution space. An application to multilateral negotiation of a travel planning is provided to demonstrate the usefulness and effectiveness of our framework.
The maximization of Tsallis entropy with complete deformed functions and the problem of constraints
International Nuclear Information System (INIS)
Oikonomou, Thomas; Bagci, G. Baris
2010-01-01
By only requiring the q deformed logarithms (q exponentials) to possess arguments chosen from the entire set of positive real numbers (all real numbers), we show that the q-logarithm (q exponential) can be written in such a way that its argument varies between 0 and 1 (among negative real numbers) for 1≤q<2, while the interval 0< q≤1 corresponds to any real argument greater than 1 (positive real numbers). These two distinct intervals of the nonextensivity index q, also the expressions of the deformed functions associated with them, are related to one another through the relation (2-q), which is so far used to obtain the ordinary stationary distributions from the corresponding escort distributions, and vice versa in an almost ad hoc manner. This shows that the escort distributions are only a means of extending the interval of validity of the deformed functions to the one of ordinary, undeformed ones. Moreover, we show that, since the Tsallis entropy is written in terms of the q-logarithm and its argument, being the inverse of microstate probabilities, takes values equal to or greater than 1, the resulting stationary solution is uniquely described by the one obtained from the ordinary constraint. Finally, we observe that even the escort stationary distributions can be obtained through the use of the ordinary averaging procedure if the argument of the q-exponential lies in (-∞,0]. However, this case corresponds to, although related, a different entropy expression than the Tsallis entropy.
Constraint Programming based Local Search for the Vehicle Routing Problem with Time Windows
Sala Reixach, Joan
2012-01-01
El projecte es centra en el "Vehicle Routing Problem with Time Windows". Explora i testeja un mètode basat en una formulació del problema en termes de programació de restriccions. Implementa un mètode de cerca local amb la capacitat de fer grans moviments anomenat "Large Neighbourhood Search".
The Higher Education Crisis in Developing Countries: Issues, Problems, Constraints and Reforms.
Salmi, Jamil
1992-01-01
Discusses the higher education crisis in developing countries in terms of the ways in which problems are analyzed and decisions are made. Focuses on discrepancies between objectives and achievements. Highlights the importance of risk analysis in strategic planning, advocating an impact assessment approach. (DMM)
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2014-01-01
Full Text Available We introduce and analyze a hybrid iterative algorithm by virtue of Korpelevich's extragradient method, viscosity approximation method, hybrid steepest-descent method, and averaged mapping approach to the gradient-projection algorithm. It is proven that under appropriate assumptions, the proposed algorithm converges strongly to a common element of the fixed point set of infinitely many nonexpansive mappings, the solution set of finitely many generalized mixed equilibrium problems (GMEPs, the solution set of finitely many variational inequality problems (VIPs, the solution set of general system of variational inequalities (GSVI, and the set of minimizers of convex minimization problem (CMP, which is just a unique solution of a triple hierarchical variational inequality (THVI in a real Hilbert space. In addition, we also consider the application of the proposed algorithm to solve a hierarchical fixed point problem with constraints of finitely many GMEPs, finitely many VIPs, GSVI, and CMP. The results obtained in this paper improve and extend the corresponding results announced by many others.
Directory of Open Access Journals (Sweden)
Yunyun Niu
2018-01-01
Full Text Available Outsourcing logistics operation to third-party logistics has attracted more attention in the past several years. However, very few papers analyzed fuel consumption model in the context of outsourcing logistics. This problem involves more complexity than traditional open vehicle routing problem (OVRP, because the calculation of fuel emissions depends on many factors, such as the speed of vehicles, the road angle, the total load, the engine friction, and the engine displacement. Our paper proposed a green open vehicle routing problem (GOVRP model with fuel consumption constraints for outsourcing logistics operations. Moreover, a hybrid tabu search algorithm was presented to deal with this problem. Experiments were conducted on instances based on realistic road data of Beijing, China, considering that outsourcing logistics plays an increasingly important role in China’s freight transportation. Open routes were compared with closed routes through statistical analysis of the cost components. Compared with closed routes, open routes reduce the total cost by 18.5% with the fuel emissions cost down by nearly 29.1% and the diver cost down by 13.8%. The effect of different vehicle types was also studied. Over all the 60- and 120-node instances, the mean total cost by using the light-duty vehicles is the lowest.
COLLAGE-BASED INVERSE PROBLEMS FOR IFSM WITH ENTROPY MAXIMIZATION AND SPARSITY CONSTRAINTS
Directory of Open Access Journals (Sweden)
Herb Kunze
2013-11-01
Full Text Available We consider the inverse problem associated with IFSM: Given a target function f, find an IFSM, such that its invariant fixed point f is sufficiently close to f in the Lp distance. In this paper, we extend the collage-based method developed by Forte and Vrscay (1995 along two different directions. We first search for a set of mappings that not only minimizes the collage error but also maximizes the entropy of the dynamical system. We then include an extra term in the minimization process which takes into account the sparsity of the set of mappings. In this new formulation, the minimization of collage error is treated as multi-criteria problem: we consider three different and conflicting criteria i.e., collage error, entropy and sparsity. To solve this multi-criteria program we proceed by scalarization and we reduce the model to a single-criterion program by combining all objective functions with different trade-off weights. The results of some numerical computations are presented. Numerical studies indicate that a maximum entropy principle exists for this approximation problem, i.e., that the suboptimal solutions produced by collage coding can be improved at least slightly by adding a maximum entropy criterion.
Portfolio selection problem with liquidity constraints under non-extensive statistical mechanics
International Nuclear Information System (INIS)
Zhao, Pan; Xiao, Qingxian
2016-01-01
In this study, we consider the optimal portfolio selection problem with liquidity limits. A portfolio selection model is proposed in which the risky asset price is driven by the process based on non-extensive statistical mechanics instead of the classic Wiener process. Using dynamic programming and Lagrange multiplier methods, we obtain the optimal policy and value function. Moreover, the numerical results indicate that this model is considerably different from the model based on the classic Wiener process, the optimal strategy is affected by the non-extensive parameter q, the increase in the investment in the risky asset is faster at a larger parameter q and the increase in wealth is similar.
International Nuclear Information System (INIS)
Ramana, M.V.; Ahmad, Ali
2016-01-01
Jordan plans to import two conventional gigawatt scale nuclear reactors from Russia that are expensive and too large for Jordan's current electricity grid. Jordan efforts to establish nuclear power might become easier in some ways if the country were to construct Small Modular Reactors, which might be better suited to Jordan's financial capabilities and its smaller electrical grid capacity. But, the SMR option raises new problems, including locating sites for multiple reactors, finding water to cool these reactors, and the higher cost of electricity generation. Jordan's decision has important implications for its energy planning as well as for the market for SMRs. - Highlights: •Jordan is planning to purchase two large reactors from Russia. •Large reactors would be inappropriate to Jordan's small electricity grid. •Small modular reactors would be more appropriate to Jordan's grid, but have problems. •The market for small modular reactors will be smaller than often projected. •Jordan should consider the financial impact of building a large nuclear reactor.
Directory of Open Access Journals (Sweden)
J. J. Escudero-Garzás
2017-01-01
Full Text Available The trend in wireless networks is that several wireless radio access technologies (RATs coexist in the same area, forming heterogeneous networks in which the users may connect to any of the available RATs. The problem of associating a user to the most suitable RAT, known as network selection problem (NSP, is of capital importance for the satisfaction of the users in these emerging environments. However, also the satisfaction of the operator is important in this scenario. In this work, we propose that a connection may be served by more than one RAT by using multi-RAT terminals. We formulate the NSP with multiple RAT association based on utility functions that take into consideration both user’s satisfaction and provider’s satisfaction. As users are characterized according to their expected quality of service, our results exhaustively analyze the influence of the user’s profile, along with the network topology and the type of applications served.
The operating room case-mix problem under uncertainty and nurses capacity constraints.
Yahia, Zakaria; Eltawil, Amr B; Harraz, Nermine A
2016-12-01
Surgery is one of the key functions in hospitals; it generates significant revenue and admissions to hospitals. In this paper we address the decision of choosing a case-mix for a surgery department. The objective of this study is to generate an optimal case-mix plan of surgery patients with uncertain surgery operations, which includes uncertainty in surgery durations, length of stay, surgery demand and the availability of nurses. In order to obtain an optimal case-mix plan, a stochastic optimization model is proposed and the sample average approximation method is applied. The proposed model is used to determine the number of surgery cases to be weekly served, the amount of operating rooms' time dedicated to each specialty and the number of ward beds dedicated to each specialty. The optimal case-mix selection criterion is based upon a weighted score taking into account both the waiting list and the historical demand of each patient category. The score aims to maximizing the service level of the operating rooms by increasing the total number of surgery cases that could be served. A computational experiment is presented to demonstrate the performance of the proposed method. The results show that the stochastic model solution outperforms the expected value problem solution. Additional analysis is conducted to study the effect of varying the number of ORs and nurses capacity on the overall ORs' performance.
Directory of Open Access Journals (Sweden)
Vinicius Amorim Sobreiro
2013-06-01
Full Text Available The definition of the product mix provides the allocation of the productive resources in the manufacture process and the optimization of productive system. However, the definition of the product mix is a problem of the NP-complete, in other words, of difficult solution. Taking this into account, with the aid of the Theory of Constraints - TOC, some constructive heuristics have been presented to help to solve this problem. Thus, the objective in this paper is to propose a new heuristics to provide better solutions when compared with the main heuristics presented in the literature, TOC-h of Fredendall and Lea. To accomplish this comparison, simulations were accomplished with the objective of identifying the production mix with the best throughput, considering CPU time and the characteristics of the productive ambient. The results show that the heuristics proposal was more satisfactory when compared to TOC-h and it shows good solution when compared with the optimum solution. This fact evidence the importance of the heuristics proposal in the definition of product mix.
Yu, Hao; Solvang, Wei Deng
2016-05-31
Hazardous waste location-routing problems are of importance due to the potential risk for nearby residents and the environment. In this paper, an improved mathematical formulation is developed based upon a multi-objective mixed integer programming approach. The model aims at assisting decision makers in selecting locations for different facilities including treatment plants, recycling plants and disposal sites, providing appropriate technologies for hazardous waste treatment, and routing transportation. In the model, two critical factors are taken into account: system operating costs and risk imposed on local residents, and a compensation factor is introduced to the risk objective function in order to account for the fact that the risk level imposed by one type of hazardous waste or treatment technology may significantly vary from that of other types. Besides, the policy instruments for promoting waste recycling are considered, and their influence on the costs and risk of hazardous waste management is also discussed. The model is coded and calculated in Lingo optimization solver, and the augmented ε-constraint method is employed to generate the Pareto optimal curve of the multi-objective optimization problem. The trade-off between different objectives is illustrated in the numerical experiment.
Directory of Open Access Journals (Sweden)
Hao Yu
2016-05-01
Full Text Available Hazardous waste location-routing problems are of importance due to the potential risk for nearby residents and the environment. In this paper, an improved mathematical formulation is developed based upon a multi-objective mixed integer programming approach. The model aims at assisting decision makers in selecting locations for different facilities including treatment plants, recycling plants and disposal sites, providing appropriate technologies for hazardous waste treatment, and routing transportation. In the model, two critical factors are taken into account: system operating costs and risk imposed on local residents, and a compensation factor is introduced to the risk objective function in order to account for the fact that the risk level imposed by one type of hazardous waste or treatment technology may significantly vary from that of other types. Besides, the policy instruments for promoting waste recycling are considered, and their influence on the costs and risk of hazardous waste management is also discussed. The model is coded and calculated in Lingo optimization solver, and the augmented ε-constraint method is employed to generate the Pareto optimal curve of the multi-objective optimization problem. The trade-off between different objectives is illustrated in the numerical experiment.
International Nuclear Information System (INIS)
Schinkel, Colleen; Stavrev, Pavel; Stavreva, Nadia; Fallone, B. Gino
2006-01-01
This paper outlines a theoretical approach to the problem of estimating and choosing dose-volume constraints. Following this approach, a method of choosing dose-volume constraints based on biological criteria is proposed. This method is called ''reverse normal tissue complication probability (NTCP) mapping into dose-volume space'' and may be used as a general guidance to the problem of dose-volume constraint estimation. Dose-volume histograms (DVHs) are randomly simulated, and those resulting in clinically acceptable levels of complication, such as NTCP of 5±0.5%, are selected and averaged producing a mean DVH that is proven to result in the same level of NTCP. The points from the averaged DVH are proposed to serve as physical dose-volume constraints. The population-based critical volume and Lyman NTCP models with parameter sets taken from literature sources were used for the NTCP estimation. The impact of the prescribed value of the maximum dose to the organ, D max , on the averaged DVH and the dose-volume constraint points is investigated. Constraint points for 16 organs are calculated. The impact of the number of constraints to be fulfilled based on the likelihood that a DVH satisfying them will result in an acceptable NTCP is also investigated. It is theoretically proven that the radiation treatment optimization based on physical objective functions can sufficiently well restrict the dose to the organs at risk, resulting in sufficiently low NTCP values through the employment of several appropriate dose-volume constraints. At the same time, the pure physical approach to optimization is self-restrictive due to the preassignment of acceptable NTCP levels thus excluding possible better solutions to the problem
Effect on marital satisfaction and life skills training in problem-solving styles housewives in Iran
Javadi Z.; Khanzadeh A.; Mousavi V.; Golandam A. K.
2012-01-01
Background and objective: Family is the most important and suitable system to resolve physical, psychological, and spiritual requirements of human being. Today, In spite of some cultural shifts and life style changes, many of the individuals, encountering life problems lack the basic and required abilities which result in family dissatisfaction and inability due to marital life's stresses that create problems and significant challenges in family system. For this reason,a better and more effec...
Lau, Joseph T F; Kim, Jean H; Tsui, Hi Yi
2005-12-01
To examine the lifestyle, mental health, and stress-related factors associated with various types of sexual problems among sexually active, heterosexual Hong Kong residents aged 18 to 59 years. An anonymous, cross-sectional, random telephone survey was conducted using a special, validated, computerized telephone interview method. A total of 1281 men and 2130 women completed the interview (response rate 50.6%). Sexual problems were determined according to the Diagnostic and Statistical Manual (of Mental Disorders) IV definitions. Among the men, multivariate analyses indicated that older age, poor spousal relationship, less exercise, high level of family stress, high level of financial-related stress, and past year substance use were significantly associated with sexual problems (odds ratio [OR] 1.41 to 3.83). Among the women, being married or cohabiting with a partner was positively associated with lubrication problems, lack of orgasm, lack of pleasure, lack of interest (OR 1.43 to 1.73) and negatively associated with pain during intercourse (OR 0.66) and anxiety (OR 0.62). A high level of financial stress and neuroses diagnoses were also associated with various female sexual problems (OR 1.40 to 2.66). Sexual satisfaction was associated with being married/cohabitating (OR 1.94) and negatively associated with a poor spousal relationship, low level of exercise, and a high level of work-related stress among men (OR 0.37 to 0.71). Among women, a poor spousal relationship and high levels of family stress and financial stress were associated with not being satisfied sexually (OR 0.24 to 0.71). Mental health, stress-related factors, and lifestyle factors contribute to sexual problems among Hong Kong Chinese adults. The factors differed between the two sexes.
Problem-Solving Management Training Effects on Sales Productivity and Job Satisfaction.
Ross, Paul C.; And Others
Research suggests that effective organizational change must be led by line personnel rather than by outside consultants. The Performance Management Program (PMP) implemented in two Bell Telephone companies is a line-led, self-help program in which managers participate in problem-solving activities within their own jobs. Marketing and sales…
An empirical study on collective intelligence algorithms for video games problem-solving
González-Pardo, Antonio; Palero, Fernando; Camacho, David
2015-01-01
Computational intelligence (CI), such as evolutionary computation or swarm intelligence methods, is a set of bio-inspired algorithms that have been widely used to solve problems in areas like planning, scheduling or constraint satisfaction problems. Constrained satisfaction problems (CSP) have taken an important attention from the research community due to their applicability to real problems. Any CSP problem is usually modelled as a constrained graph where the edges represent a set of restri...
Donohue, Brad; Teichner, Gordon; Azrin, Nathan; Weintraub, Noah; Crum, Thomas A.; Murphy, Leah; Silver, N. Clayton
2003-01-01
Responses to Life Satisfaction Scale for Problem Youth (LSSPY) items were examined in a sample of 193 substance abusing and conduct disordered adolescents. In responding to the LSSPY, youth endorse their percentage of happiness (0 to 100%) in twelve domains (i.e., friendships, family, school, employment/work, fun activities, appearance, sex…
Jiménez-Mejías, E.; Amezcua-Prieto, C.; Martínez-Ruiz, V.; Olvera-Porcel, M. C.; Jiménez-Moleón, J. J.; Lardelli Claret, P.
2015-01-01
The aim of this study was to evaluate the effect of problem-based learning (PBL) on university students' satisfaction with and academic performance in a course on epidemiology and social and demographic health. The participants in this interventional study were 529 students (272 in the intervention group and 257 in the control group) enrolled in a…
Solving Large-Scale Computational Problems Using Insights from Statistical Physics
Energy Technology Data Exchange (ETDEWEB)
Selman, Bart [Cornell University
2012-02-29
Many challenging problems in computer science and related fields can be formulated as constraint satisfaction problems. Such problems consist of a set of discrete variables and a set of constraints between those variables, and represent a general class of so-called NP-complete problems. The goal is to find a value assignment to the variables that satisfies all constraints, generally requiring a search through and exponentially large space of variable-value assignments. Models for disordered systems, as studied in statistical physics, can provide important new insights into the nature of constraint satisfaction problems. Recently, work in this area has resulted in the discovery of a new method for solving such problems, called the survey propagation (SP) method. With SP, we can solve problems with millions of variables and constraints, an improvement of two orders of magnitude over previous methods.
International Nuclear Information System (INIS)
Khalili-Damghani, Kaveh; Amiri, Maghsoud
2012-01-01
In this paper, a procedure based on efficient epsilon-constraint method and data envelopment analysis (DEA) is proposed for solving binary-state multi-objective reliability redundancy allocation series-parallel problem (MORAP). In first module, a set of qualified non-dominated solutions on Pareto front of binary-state MORAP is generated using an efficient epsilon-constraint method. In order to test the quality of generated non-dominated solutions in this module, a multi-start partial bound enumeration algorithm is also proposed for MORAP. The performance of both procedures is compared using different metrics on well-known benchmark instance. The statistical analysis represents that not only the proposed efficient epsilon-constraint method outperform the multi-start partial bound enumeration algorithm but also it improves the founded upper bound of benchmark instance. Then, in second module, a DEA model is supplied to prune the generated non-dominated solutions of efficient epsilon-constraint method. This helps reduction of non-dominated solutions in a systematic manner and eases the decision making process for practical implementations. - Highlights: ► A procedure based on efficient epsilon-constraint method and DEA was proposed for solving MORAP. ► The performance of proposed procedure was compared with a multi-start PBEA. ► Methods were statistically compared using multi-objective metrics.
International Nuclear Information System (INIS)
Frittelli, Simonetta; Gomez, Roberto
2004-01-01
We show how the use of the normal projection of the Einstein tensor as a set of boundary conditions relates to the propagation of the constraints, for two representations of the Einstein equations with vanishing shift vector: the Arnowitt-Deser-Misner formulation, which is ill posed, and the Einstein-Christoffel formulation, which is symmetric hyperbolic. Essentially, the components of the normal projection of the Einstein tensor that act as nontrivial boundary conditions are linear combinations of the evolution equations with the constraints that are not preserved at the boundary, in both cases. In the process, the relationship of the normal projection of the Einstein tensor to the recently introduced 'constraint-preserving' boundary conditions becomes apparent
Directory of Open Access Journals (Sweden)
Hüseyin YILMAZ
2016-12-01
Full Text Available The aim of this study is the creative problem-solving capacity of the organization with leadership behaviors of human resources managers and employees to examine the relationship between career satisfaction and is tested empirically. Research within the scope of the required data structured questionnaire method, operating in the province of Aydin was obtained from 130 employees working in five star hotels. Democratic leadership style according to the factor analysis, easygoing, participants converter, and releasing autocratic leadership dimensions were determined. According to the analysis, the dependent variable with a significant level of research and positive leadership style has been determined that no relationships. Regression analysis revealed that the leadership of the relationship with the creative problem-solving capacity of democratic leadership in style when found to be stronger than other leadership styles, while the variable describing the career of the employee satisfaction level of the maximum it was concluded that the creative problem-solving capacity of the organization. Research in the context of human resources on the very important for organizations, leadership behavior, creative problem-solving capacity and career satisfaction studies analyzing the relationships between variables it seems to be quite limited. The discovery by analyzing the relationship between the aforementioned variables, can make significant contributions to knowledge in the literature and are expected to form the basis for future research.
Leung, Shirley S L; Leung, Cynthia; Chan, Ruth
2007-10-01
To compare parental perception of child behaviour problems, parenting stress, and marital satisfaction in new arrival and local parents. Cross-sectional survey; semi-structured interview. Maternal and Child Health Centres, social service centres, preschools. Parents of preschool children, including new arrival parents and local parents. Child behaviour problems, parenting stress, and marital satisfaction. After controlling for socio-economic factors, new arrival parents were more troubled by their children's behaviour problems and their parent-child interactions were more dysfunctional than those of local parents. There were no differences in parent-reported severity of child behaviour problems, parental distress, and marital satisfaction. New arrival parents reported difficulties in adapting to the new living environment and lack of social support. New arrival parents were more troubled by their children's behaviour, and their parent-child interactions were more dysfunctional than those of local parents. These might in part be related to their settlement difficulties. Parenting programmes should address their specific settlement needs.
Hüseyin YILMAZ
2016-01-01
The aim of this study is the creative problem-solving capacity of the organization with leadership behaviors of human resources managers and employees to examine the relationship between career satisfaction and is tested empirically. Research within the scope of the required data structured questionnaire method, operating in the province of Aydin was obtained from 130 employees working in five star hotels. Democratic leadership style according to the factor analysis, easygoing, participants c...
Jefford, M; Mileshkin, L; Matthews, J; Raunow, H; O'Kane, C; Cavicchiolo, T; Brasier, H; Anderson, M; Reynolds, J
2011-03-01
Partially presented in poster format at the 40th and 41st Annual Meetings of the American Society of Clinical Oncology, held in 2004 in New Orleans, Louisiana and in 2005 in Orlando, Florida. We aimed to: (a) assess patient knowledge about cancer clinical trials (CCT) and satisfaction with their decision to participate, (b) determine whether satisfaction correlates with objective understanding, or other factors, and (c) identify correlates of increased understanding. A convenience sample of 100 patients were recruited. Instruments assessed quality of informed consent (QuIC), quality of life (EORTC QLQ C-30), anxiety and depression (HADS), and preferences for information and involvement in decision making. Measures were completed within 2 weeks of clinical trial enrollment. One hundred two patients (68 male) with a median age of 58.4 years (29-85) were registered in 27 of the 33 therapeutic cancer clinical trials approved for the Consent Study. Mean QuIC objective knowledge (QuIC-A) was 77.6 (/100) (95% CI, 75.7-79.4) and perceived (subjective) understanding (QuIC-B) 91.5 (95% CI, 89.6-93.3). There was low but significant correlation between QuIC-A and B (R = 0.26, p = 0.008). Satisfaction was very high. Correlation between QuIC-B and satisfaction was moderate (0.430, p < 0.001). QuIC-B, but not QuIC-A was associated with QOL scores. Preferences regarding participation in decision making and whether these preferences were achieved did not impact upon knowledge, understanding or satisfaction. Patient knowledge regarding CCT is similar to published US data, and satisfaction is high. Satisfaction correlates with perceived but not objective understanding of CCT. Strategies to further improve the consent process need to be developed.
Evaluating Distributed Timing Constraints
DEFF Research Database (Denmark)
Kristensen, C.H.; Drejer, N.
1994-01-01
In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....
DEFF Research Database (Denmark)
Ragnarson Tennvall, Gunnel; Hjortsberg, Catharina; Bjarnason, Anton
2012-01-01
Biological drugs are expensive, but can reduce symptoms and increase quality of life for patients with psoriasis. The aim of this study was to examine quality of life, disease severity and treatment satisfaction in Danish, Finnish and Swedish patients with psoriasis. Based on 12 months' data from...
Eklund, Mona; Bäckström, Martin; Eakman, Aaron M
2014-12-24
In mental health care practice and research it is increasingly recognized that clients' subjective perceptions of everyday occupations, such as satisfaction, are important in recovery from mental illness. Instruments thus need to be developed to assess satisfaction with everyday occupations. The aim of the present study was to assess psychometric properties of the 13-item Satisfaction with Daily Occupation (SDO-13) when used with people with mental health problems, including its internal consistency, factor structure, construct validity and whether the scale produced ceiling or floor effects. An additional question concerned if the factor structure varied whether the participants were, or were not, presently engaged in the activity they rated. The interview-based SDO-13 includes items pertaining to work/studies, leisure, home maintenance, and self-care occupations. Whether the person currently performs an occupation or not, he/she is asked to indicate his/her satisfaction with that occupation. The SDO-13 was completed with 184 persons with mental illness. Residual variables were created to remove the variation linked with currently performing the targeted occupation or not and to assess the factor structure of the SDO-13. The indicators of general satisfaction with daily occupations, self-esteem and global functioning were used to assess construct validity. The statistical methods included tests of homogeneity, confirmatory factor analysis and Pearson correlations. The internal consistency was satisfactory at 0.79. A three-factor solution indicated that the construct behind the SDO-13 was composed of three facets; Taking care of oneself and the home, Work and studies, and Leisure and relaxation. The same factor structure was valid for both original scores and the residuals. An expected pattern of correlations with the indicators was mainly found, suggesting basic construct validity. No ceiling or floor effects were found. Taken together, the findings suggest the
Directory of Open Access Journals (Sweden)
Sanghee Yeo
2016-03-01
Full Text Available Purpose: Kyungpook National University School of Medicine has been implementing hybrid problem-based learning (PBL since 1999. The aim of this study was to investigate the changes in the students’ perceptions and satisfaction levels of hybrid PBL. Methods: The target period of our study was from 1999 to 2014, and target subjects were second-year medical students in Kyungpook National University School of Medicine. The survey was conducted at the end of semester. We had a focused interview with group leaders and some volunteer students. Results: As for the scores regarding students’ overall satisfaction with PBL, there was significant improvement in 2005 compared to 2002, but the scores decreased and no differences between the survey years noted after 2005. The students’ preference ratio for the once a week PBL sessions, tutor presence, synchronization of contents, and arrangement of PBL sessions and related lectures was 60%–80%, 50%–90%, 52%–96%, and 78%–93%, respectively. Conclusion: In order to increase students’ satisfaction with hybrid PBL and to improve the perception of it, firstly, it is necessary to arrange the date and the time of PBL sessions so that students can concentrate on PBL. Secondly, PBL cases should be selected and arranged to be well synchronized with the ongoing lectures. Finally, it is important to create a safe atmosphere so that students can engage actively in PBL sessions.
Huang, Hui-Chun; Shanklin, Carol W
2008-05-01
The United States is experiencing remarkable growth in the elderly population, which provides both opportunities and challenges for assisted-living facilities. The objective of this study was to explore how service management influences residents' actual food consumption in assisted-living facilities. Physical factors influencing residents' service evaluation and food consumption also were investigated. A total of 394 questionnaires were distributed to assisted-living residents in seven randomly selected facilities. The questionnaire was developed based on an in-depth literature review and pilot study. Residents' perceived quality evaluations, satisfaction, and physical constraints were measured. Residents' actual food consumption was measured using a plate waste technique. A total of 118 residents in five facilities completed both questionnaires and food consumption assessments. Descriptive, multivariate analyses and structural equation modeling techniques were employed. Service management, including food and service quality and customer satisfaction, was found to significantly influence residents' food consumption. Physical constraints associated with aging, including a decline in health status, chewing problems, sensory loss, and functional disability, also significantly influenced residents' food consumption. A significant relationship was found between physical constraints and customer satisfaction. Foodservice that provides good food and service quality increases customer satisfaction and affects residents' actual food consumption. Physical constraints also influence residents' food consumption directly, or indirectly through satisfaction. The findings suggest that food and nutrition professionals in assisted-living should consider the physical profiles of their residents to enhance residents' satisfaction and nutrient intake. Recommendations for exploring residents' perspectives are discussed.
Kok, de A.G.; Tijms, H.C.; Duyn Schouten, van der F.A.
1984-01-01
We consider a production-inventory problem in which the production rate can be continuously controlled in order to cope with random fluctuations in the demand. The demand process for a single product is a compound Poisson process. Excess demand is backlogged. Two production rates are available and
Ahmad, Ikhlas; Vansteenkiste, Maarten; Soenens, Bart
2013-01-01
Although the effects of important parenting dimensions, such as responsiveness and psychological control, are well documented among Western populations, research has only recently begun to systematically identify psychological processes that may account for the cross-cultural generalization of these effects. A first aim of this study was to examine whether perceived maternal responsiveness and psychological control would relate differentially to teacher ratings of adolescent adjustment in a vertical-collectivist society (i.e., Jordan). The most important aim of this study was to examine, on the basis of self-determination theory, whether these associations would be accounted for by perceived satisfaction of the basic psychological needs for autonomy, competence, and relatedness. Results in a large sample of Jordanian adolescents (N = 545) showed that perceived maternal psychological control and responsiveness yielded, respectively, a positive and negative association with teacher-rated problems, whereas psychological control was negatively related to teacher-rated adjustment. Further, these 2 parenting dimensions related to adjustment and problems via perceived satisfaction of the basic psychological needs for autonomy and competence (but not relatedness). The findings are discussed in light of the ongoing debate between universalistic and relativistic perspectives on parenting and adolescent adjustment.
International Nuclear Information System (INIS)
Morais, Sebastien
2016-01-01
In many scientific areas, the size and the complexity of numerical simulations lead to make intensive use of massively parallel runs on High Performance Computing (HPC) architectures. Such computers consist in a set of processing units (PU) where memory is distributed. Distribution of simulation data is therefore crucial: it has to minimize the computation time of the simulation while ensuring that the data allocated to every PU can be locally stored in memory. For most of the numerical simulations, the physical and numerical data are based on a mesh. The computations are then performed at the cell level (for example within triangles and quadrilaterals in 2D, or within tetrahedrons and hexahedrons in 3D). More specifically, computing and memory cost can be associated to each cell. In our context, where the mathematical methods used are finite elements or finite volumes, the realization of the computations associated with a cell may require information carried by neighboring cells. The standard implementation relies to locally store useful data of this neighborhood on the PU, even if cells of this neighborhood are not locally computed. Such non computed but stored cells are called ghost cells, and can have a significant impact on the memory consumption of a PU. The problem to solve is thus not only to partition a mesh on several parts by affecting each cell to one and only one part while minimizing the computational load assigned to each part. It is also necessary to keep into account that the memory load of both the cells where the computations are performed and their neighbors has to fit into PU memory. This leads to partition the computations while the mesh is distributed with overlaps. Explicitly taking these data overlaps into account is the problem that we propose to study. (author) [fr
Statistical physics of hard optimization problems
International Nuclear Information System (INIS)
Zdeborova, L.
2009-01-01
Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial (NP)-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this article is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfy ability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named ”locked” constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfy ability.
Statistical physics of hard optimization problems
International Nuclear Information System (INIS)
Zdeborova, L.
2009-01-01
Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an non-deterministic polynomial-complete problem the practically arising instances might, in fact, be easy to solve. The principal the question we address in the article is: How to recognize if an non-deterministic polynomial-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named 'locked' constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability (Authors)
Statistical physics of hard optimization problems
Zdeborová, Lenka
2009-06-01
Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial (NP)-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this article is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named "locked" constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability.
Procedural Design of Exterior Lighting for Buildings with Complex Constraints
Schwarz, Michael
2014-10-01
We present a system for the lighting design of procedurally modeled buildings. The design is procedurally specified as part of the ordinary modeling workflow by defining goals for the illumination that should be attained and locations where luminaires may be installed to realize these goals. Additionally, constraints can be modeled that make the arrangement of the installed luminaires respect certain aesthetic and structural considerations. From this specification, the system automatically generates a lighting solution for any concrete model instance. The underlying, intricate joint optimization and constraint satisfaction problem is approached with a stochastic scheme that operates directly in the complex subspace where all constraints are observed. To navigate this subspace efficaciously, the actual lighting situation is taken into account. We demonstrate our system on multiple examples spanning a variety of architectural structures and lighting designs. Copyright held by the Owner/Author.
Duality in constrained location problems
DEFF Research Database (Denmark)
Juel, Henrik; Love, Robert F.
1987-01-01
The dual of a facility location problem with general norms, distance constraints, and linear constraints is formulated.......The dual of a facility location problem with general norms, distance constraints, and linear constraints is formulated....
Pinsonneault, Marc H.; Stauffer, John; Soderblom, David R.; King, Jeremy R.; Hanson, Robert B.
1998-01-01
Parallax data from the Hipparcos mission allow the direct distance to open clusters to be compared with the distance inferred from main-sequence (MS) fitting. There are surprising differences between the two distance measurements. indicating either the need for changes in the cluster compositions or reddening, underlying problems with the technique of MS fitting, or systematic errors in the Hipparcos parallaxes at the 1 mas level. We examine the different possibilities, focusing on MS fitting in both metallicity-sensitive B-V and metallicity-insensitive V-I for five well-studied systems (the Hyades, Pleiades, alpha Per, Praesepe, and Coma Ber). The Hipparcos distances to the Hyades and alpha Per are within 1 sigma of the MS-fitting distance in B-V and V-I, while the Hipparcos distances to Coma Ber and the Pleiades are in disagreement with the MS-fitting distance at more than the 3 sigma level. There are two Hipparcos measurements of the distance to Praesepe; one is in good agreement with the MS-fitting distance and the other disagrees at the 2 sigma level. The distance estimates from the different colors are in conflict with one another for Coma but in agreement for the Pleiades. Changes in the relative cluster metal abundances, age related effects, helium, and reddening are shown to be unlikely to explain the puzzling behavior of the Pleiades. We present evidence for spatially dependent systematic errors at the 1 mas level in the parallaxes of Pleiades stars. The implications of this result are discussed.
Improvement of DC Optimal Power Flow Problem Based on Nodal Approximation of Transmission Losses
Directory of Open Access Journals (Sweden)
M. R. Baghayipour
2012-03-01
3-\tIts formulation is simple and easy to understand. Moreover, it can simply be realized in the form of Lagrange representation, makes it possible to be considered as some constraints in the body of any bi-level optimization problem, with its internal level including the OPF problem satisfaction.
Directory of Open Access Journals (Sweden)
Arnaud Gotlieb
2013-02-01
Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.
Mulcahy, Robert Sean
2010-01-01
Learners inevitably enter adult technical training classrooms--indeed, in all classrooms--with different levels of expertise on the subject matter. When the diversity of expertise is wide and the course makes use of small group problem solving, instructors have a choice about how to group learners: they may distribute learners with greater…
Constraint-satisfaction inference for entity recognition
Canisius, S.V.M.; Bosch, A.P.J. van den; Daelemans, W.M.P.; Bosch, A.P.J. van den; Bouma, G.
2011-01-01
One approach to QA answering is to match a question to candidate answers in a background corpus based on semantic overlap, possibly in combination with other levels of matching, such as lexical vector space similarity and syntactic similarity. While the computation of deep semantic similarity is as
Dynamics and causality constraints
International Nuclear Information System (INIS)
Sousa, Manoelito M. de
2001-04-01
The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)
Directory of Open Access Journals (Sweden)
Bhanu Prakash
2010-01-01
Full Text Available Patient satisfaction is an important and commonly used indicator for measuring the quality in health care. Patient satisfaction affects clinical outcomes, patient retention, and medical malpractice claims. It affects the timely, efficient, and patient-centered delivery of quality health care. Patient satisfaction is thus a proxy but a very effective indicator to measure the success of doctors and hospitals. This article discusses as to how to ensure patient satisfaction in dermatological practice.
PODROUŽKOVÁ, Lucie
2013-01-01
Bachelor thesis deals with job satisfaction. It is often given to a context with the attitude to work which is very much connected to job satisfaction. Thesis summarises all the pieces of information about job satisfacion, factors that affect it negatively and positively, interconnection of work satisfaction and work motivation, work behaviour and performance of workers, relationship of a man and work and at last general job satisfaction and its individual aspects. In the thesis I shortly pay...
Prakash, Bhanu
2010-09-01
Patient satisfaction is an important and commonly used indicator for measuring the quality in health care. Patient satisfaction affects clinical outcomes, patient retention, and medical malpractice claims. It affects the timely, efficient, and patient-centered delivery of quality health care. Patient satisfaction is thus a proxy but a very effective indicator to measure the success of doctors and hospitals. This article discusses as to how to ensure patient satisfaction in dermatological practice.
Directory of Open Access Journals (Sweden)
MJ Rezaie
2013-05-01
Full Text Available Background and purpose: Problem-based learning (PBL is a term used within education for a range of teaching approaches that encourage students to learn through the structured exploration of a problem. Histology comes early in the curriculum and the medical students seem unable to see the value of the content, they don't appear to be motivated to learn the content. This project used PBL to help the students make the connection between the content and clinical aspects.Methods: Thirty six undergraduate medical students, 22 female and 14 male, enrolled in the histology course during the spring semester of 2008. A survey which collected information relative to gender, course load, and workload and study time was used. The subjects were accessory glands of digestive system histology. The course is designed into four units: tree units of salivary glands, pancreas and gall bladder histology, were presented in a traditional lecture format; the fourth unit, liver was presented in a problem-based format that used clinical practice. Assessment focused on three issues of a. student engagement, b. lesson assessment in terms of clarity, interest and usefulness and c. student understanding.Results: Student comments collected during PBL class periods indicate engagement in the topic. In PBL method of teaching most of responses were consistent with the aim of teaching but in traditional classes few responses relate to the objectives at hand. Students had more active partnership in PBL class. Students found PBL class more useful, interesting and clear in terms of subject material than traditional method.Conclusions: In this project student comments collected during PBL class periods indicated more engagement in the topic. Students’ understanding of material were significantly higher and students’ partnership in PBL class was more than traditional classes.Keywords: PBL,HISTOLOGY, STUDENT PARTICIPATION
Meresescu, Alina G.; Kowalski, Matthieu; Schmidt, Frédéric; Landais, François
2018-06-01
The Water Residence Time distribution is the equivalent of the impulse response of a linear system allowing the propagation of water through a medium, e.g. the propagation of rain water from the top of the mountain towards the aquifers. We consider the output aquifer levels as the convolution between the input rain levels and the Water Residence Time, starting with an initial aquifer base level. The estimation of Water Residence Time is important for a better understanding of hydro-bio-geochemical processes and mixing properties of wetlands used as filters in ecological applications, as well as protecting fresh water sources for wells from pollutants. Common methods of estimating the Water Residence Time focus on cross-correlation, parameter fitting and non-parametric deconvolution methods. Here we propose a 1D full-deconvolution, regularized, non-parametric inverse problem algorithm that enforces smoothness and uses constraints of causality and positivity to estimate the Water Residence Time curve. Compared to Bayesian non-parametric deconvolution approaches, it has a fast runtime per test case; compared to the popular and fast cross-correlation method, it produces a more precise Water Residence Time curve even in the case of noisy measurements. The algorithm needs only one regularization parameter to balance between smoothness of the Water Residence Time and accuracy of the reconstruction. We propose an approach on how to automatically find a suitable value of the regularization parameter from the input data only. Tests on real data illustrate the potential of this method to analyze hydrological datasets.
A HYBRID ALGORITHM FOR THE ROBUST GRAPH COLORING PROBLEM
Directory of Open Access Journals (Sweden)
Román Anselmo Mora Gutiérrez
2016-08-01
Full Text Available A hybridalgorithm which combines mathematical programming techniques (Kruskal’s algorithm and the strategy of maintaining arc consistency to solve constraint satisfaction problem “CSP” and heuristic methods (musical composition method and DSATUR to resolve the robust graph coloring problem (RGCP is proposed in this paper. Experimental result shows that this algorithm is better than the other algorithms presented on the literature.
Controlled neural network application in track-match problem
International Nuclear Information System (INIS)
Baginyan, S.A.; Ososkov, G.A.
1993-01-01
Track-match problem of high energy physics (HEP) data handling is formulated in terms of incidence matrices. The corresponding Hopfield neural network is developed to solve this type of constraint satisfaction problems (CSP). A special concept of the controlled neural network is proposed as a basis of an algorithm for the effective CSP solution. Results of comparable calculations show the very high performance of this algorithm against conventional search procedures. 8 refs.; 1 fig.; 1 tab
Judgement of Design Scheme Based on Flexible Constraint in ICAD
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The conception of flexible constraint is proposed in the paper. The solution of flexible constraint is in special range, and maybe different in different instances of same design scheme. The paper emphasis on how to evaluate and optimize a design scheme with flexible constraints based on the satisfaction degree function defined on flexible constraints. The conception of flexible constraint is used to solve constraint conflict and design optimization in complicated constraint-based assembly design by the PFM parametrization assembly design system. An instance of gear-box design is used for verifying optimization method.
International Nuclear Information System (INIS)
Provost, J.
1984-01-01
Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities. (Auth.)
International Nuclear Information System (INIS)
Jones, P.M.S.
1987-01-01
There are considerable incentives for the use of nuclear in preference to other sources for base load electricity generation in most of the developed world. These are economic, strategic, environmental and climatic. However, there are two potential constraints which could hinder the development of nuclear power to its full economic potential. These are public opinion and financial regulations which distort the nuclear economic advantage. The concerns of the anti-nuclear lobby are over safety, (especially following the Chernobyl accident), the management of radioactive waste, the potential effects of large scale exposure of the population to radiation and weapons proliferation. These are discussed. The financial constraint is over two factors, the availability of funds and the perception of cost, both of which are discussed. (U.K.)
Implicit Motives and Men's Perceived Constraint in Fatherhood.
Ruppen, Jessica; Waldvogel, Patricia; Ehlert, Ulrike
2016-01-01
Research shows that implicit motives influence social relationships. However, little is known about their role in fatherhood and, particularly, how men experience their paternal role. Therefore, this study examined the association of implicit motives and fathers' perceived constraint due to fatherhood. Furthermore, we explored their relation to fathers' life satisfaction. Participants were fathers with biological children ( N = 276). They were asked to write picture stories, which were then coded for implicit affiliation and power motives. Perceived constraint and life satisfaction were assessed on a visual analog scale. A higher implicit need for affiliation was significantly associated with lower perceived constraint, whereas the implicit need for power had the opposite effect. Perceived constraint had a negative influence on life satisfaction. Structural equation modeling revealed significant indirect effects of implicit affiliation and power motives on life satisfaction mediated by perceived constraint. Our findings indicate that men with a higher implicit need for affiliation experience less constraint due to fatherhood, resulting in higher life satisfaction. The implicit need for power, however, results in more perceived constraint and is related to decreased life satisfaction.
Implicit Motives and Men’s Perceived Constraint in Fatherhood
Ruppen, Jessica; Waldvogel, Patricia; Ehlert, Ulrike
2016-01-01
Research shows that implicit motives influence social relationships. However, little is known about their role in fatherhood and, particularly, how men experience their paternal role. Therefore, this study examined the association of implicit motives and fathers’ perceived constraint due to fatherhood. Furthermore, we explored their relation to fathers’ life satisfaction. Participants were fathers with biological children (N = 276). They were asked to write picture stories, which were then coded for implicit affiliation and power motives. Perceived constraint and life satisfaction were assessed on a visual analog scale. A higher implicit need for affiliation was significantly associated with lower perceived constraint, whereas the implicit need for power had the opposite effect. Perceived constraint had a negative influence on life satisfaction. Structural equation modeling revealed significant indirect effects of implicit affiliation and power motives on life satisfaction mediated by perceived constraint. Our findings indicate that men with a higher implicit need for affiliation experience less constraint due to fatherhood, resulting in higher life satisfaction. The implicit need for power, however, results in more perceived constraint and is related to decreased life satisfaction. PMID:27933023
Implicit Motives and Men’s Perceived Constraint in Fatherhood
Directory of Open Access Journals (Sweden)
Jessica Ruppen
2016-11-01
Full Text Available Research shows that implicit motives influence social relationships. However, little is known about their role in fatherhood and, particularly, how men experience their paternal role. Therefore, this study examined the association of implicit motives and fathers’ perceived constraint due to fatherhood. Furthermore, we explored their relation to fathers’ life satisfaction. Participants were fathers with biological children (N = 276. They were asked to write picture stories, which were then coded for implicit affiliation and power motives. Perceived constraint and life satisfaction were assessed on a visual analog scale. A higher implicit need for affiliation was significantly associated with lower perceived constraint, whereas the implicit need for power had the opposite effect. Perceived constraint had a negative influence on life satisfaction. Structural equation modeling revealed significant indirect effects of implicit affiliation and power motives on life satisfaction mediated by perceived constraint. Our findings indicate that men with a higher implicit need for affiliation experience less constraint due to fatherhood, resulting in higher life satisfaction. The implicit need for power, however, results in more perceived constraint and is related to decreased life satisfaction.
Vukmir, Rade B
2006-01-01
This paper seeks to present an analysis of the literature examining objective information concerning the subject of customer service, as it applies to the current medical practice. Hopefully, this information will be synthesized to generate a cogent approach to correlate customer service with quality. Articles were obtained by an English language search of MEDLINE from January 1976 to July 2005. This computerized search was supplemented with literature from the author's personal collection of peer-reviewed articles on customer service in a medical setting. This information was presented in a qualitative fashion. There is a significant lack of objective data correlating customer service objectives, patient satisfaction and quality of care. Patients present predominantly for the convenience of emergency department care. Specifics of satisfaction are directed to the timing, and amount of "caring". Demographic correlates including symptom presentation, practice style, location and physician issues directly impact on satisfaction. It is most helpful to develop a productive plan for the "difficult patient", emphasizing communication and empathy. Profiling of the customer satisfaction experience is best accomplished by examining the specifics of satisfaction, nature of the ED patient, demographic profile, symptom presentation and physician interventions emphasizing communication--especially with the difficult patient. The current emergency medicine customer service dilemmas are a complex interaction of both patient and physician factors specifically targeting both efficiency and patient satisfaction. Awareness of these issues particular to the emergency patient can help to maximize efficiency, minimize subsequent medicolegal risk and improve patient care if a tailored management plan is formulated.
Machine tongues. X. Constraint languages
Energy Technology Data Exchange (ETDEWEB)
Levitt, D.
Constraint languages and programming environments will help the designer produce a lucid description of a problem domain, and then of particular situations and problems in it. Early versions of these languages were given descriptions of real world domain constraints, like the operation of electrical and mechanical parts. More recently, the author has automated a vocabulary for describing musical jazz phrases, using constraint language as a jazz improviser. General constraint languages will handle all of these domains. Once the model is in place, the system will connect built-in code fragments and algorithms to answer questions about situations; that is, to help solve problems. Bugs will surface not in code, but in designs themselves. 15 references.
Strict Constraint Feasibility in Analysis and Design of Uncertain Systems
Crespo, Luis G.; Giesy, Daniel P.; Kenny, Sean P.
2006-01-01
This paper proposes a methodology for the analysis and design optimization of models subject to parametric uncertainty, where hard inequality constraints are present. Hard constraints are those that must be satisfied for all parameter realizations prescribed by the uncertainty model. Emphasis is given to uncertainty models prescribed by norm-bounded perturbations from a nominal parameter value, i.e., hyper-spheres, and by sets of independently bounded uncertain variables, i.e., hyper-rectangles. These models make it possible to consider sets of parameters having comparable as well as dissimilar levels of uncertainty. Two alternative formulations for hyper-rectangular sets are proposed, one based on a transformation of variables and another based on an infinity norm approach. The suite of tools developed enable us to determine if the satisfaction of hard constraints is feasible by identifying critical combinations of uncertain parameters. Since this practice is performed without sampling or partitioning the parameter space, the resulting assessments of robustness are analytically verifiable. Strategies that enable the comparison of the robustness of competing design alternatives, the approximation of the robust design space, and the systematic search for designs with improved robustness characteristics are also proposed. Since the problem formulation is generic and the solution methods only require standard optimization algorithms for their implementation, the tools developed are applicable to a broad range of problems in several disciplines.
Zweben, Monte
1993-01-01
The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.
Arfawi Kurdhi, Nughthoh; Adi Diwiryo, Toray; Sutanto
2016-02-01
This paper presents an integrated single-vendor two-buyer production-inventory model with stochastic demand and service level constraints. Shortage is permitted in the model, and partial backordered partial lost sale. The lead time demand is assumed follows a normal distribution and the lead time can be reduced by adding crashing cost. The lead time and ordering cost reductions are interdependent with logaritmic function relationship. A service level constraint policy corresponding to each buyer is considered in the model in order to limit the level of inventory shortages. The purpose of this research is to minimize joint total cost inventory model by finding the optimal order quantity, safety stock, lead time, and the number of lots delivered in one production run. The optimal production-inventory policy gained by the Lagrange method is shaped to account for the service level restrictions. Finally, a numerical example and effects of the key parameters are performed to illustrate the results of the proposed model.
DEFF Research Database (Denmark)
Eskildsen, Jacob Kjær; Kristensen, Kai
2007-01-01
& Westlund, 2003) as well as the structure of the framework (Eskildsen et al., 2004). We know however very little about how the structure of the individual markets with respect to, for instance, how the transparency of products and services affects customer satisfaction. The aim of this article is to analyze...... the effect of the transparency of products and services on customer satisfaction with respect to Danish mobile phone companies, banks and supermarkets from 2004 based on the authors' experiences from the various analyses conducted within the EPSI rating initiative....
A combined constraint handling framework: an empirical study
DEFF Research Database (Denmark)
Si, Chengyong; Hu, Junjie; Lan, Tian
2017-01-01
This paper presents a new combined constraint handling framework (CCHF) for solving constrained optimization problems (COPs). The framework combines promising aspects of different constraint handling techniques (CHTs) in different situations with consideration of problem characteristics. In order...
African Journals Online (AJOL)
Administrator
Job Satisfaction: Rural Versus Urban Primary Health Care Workers'. Perception in ... doing it well, and being suitably rewarded for one's efforts. Several ... community recognition of their work and improved staff relationship. ..... study found important differences about attractors to ... their work, work-life balance, bureaucracy.
Job satisfaction of nursing assistants.
Lerner, Nancy; Resnick, Barbara; Galik, Elizabeth; Flynn, Linda
2011-11-01
This secondary data analysis explored factors influencing job satisfaction in a sample of nursing assistants employed in Maryland skilled nursing facilities. Multiple factors have been shown to affect job satisfaction and turnover in nursing assistants (NAs), but the problem of turnover persists in skilled nursing facility environments affecting quality of care. An existing data set of 556 nursing assistants from 12 Maryland skilled nursing facilities was used. To explore factors found to influence job satisfaction from other studies, a multiple regression analysis was performed. Nine dependent variables previously shown to affect job satisfaction were used. Of these variables, only years of experience (β = .230) and performance of restorative care (β = .095) were found to be positively associated with job satisfaction. Self-esteem (β = -.094) was found to be negatively associated with job satisfaction. Only length of experience and exemplary care as evidenced by the performance of restorative care were associated with job satisfaction. These results mirror results found in other studies. Self-esteem was negatively associated with job satisfaction in this population, a finding needing further study. Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Motivators of teacher job satisfaction
Juozaitienė, Agnė; Simonaitienė, Berita
2011-01-01
Article is seeking to answer these questions: what factors function as motivators and enhance teacher job satisfaction and which of the motivators are manifested at school? These questions are significant from a theoretical as well as practical point of view. The research problem addressed in the article encompasses three fields and is revealed in three parts of the article. The first part analyzes the notion of teacher job satisfaction and influencing factors. The second part is dedicated to...
Constraint programming and decision making
Kreinovich, Vladik
2014-01-01
In many application areas, it is necessary to make effective decisions under constraints. Several area-specific techniques are known for such decision problems; however, because these techniques are area-specific, it is not easy to apply each technique to other applications areas. Cross-fertilization between different application areas is one of the main objectives of the annual International Workshops on Constraint Programming and Decision Making. Those workshops, held in the US (El Paso, Texas), in Europe (Lyon, France), and in Asia (Novosibirsk, Russia), from 2008 to 2012, have attracted researchers and practitioners from all over the world. This volume presents extended versions of selected papers from those workshops. These papers deal with all stages of decision making under constraints: (1) formulating the problem of multi-criteria decision making in precise terms, (2) determining when the corresponding decision problem is algorithmically solvable; (3) finding the corresponding algorithms, and making...
Declarative Programming with Temporal Constraints, in the Language CG
Directory of Open Access Journals (Sweden)
Lorina Negreanu
2015-01-01
Full Text Available Specifying and interpreting temporal constraints are key elements of knowledge representation and reasoning, with applications in temporal databases, agent programming, and ambient intelligence. We present and formally characterize the language CG, which tackles this issue. In CG, users are able to develop time-dependent programs, in a flexible and straightforward manner. Such programs can, in turn, be coupled with evolving environments, thus empowering users to control the environment’s evolution. CG relies on a structure for storing temporal information, together with a dedicated query mechanism. Hence, we explore the computational complexity of our query satisfaction problem. We discuss previous implementation attempts of CG and introduce a novel prototype which relies on logic programming. Finally, we address the issue of consistency and correctness of CG program execution, using the Event-B modeling approach.
Declarative Programming with Temporal Constraints, in the Language CG.
Negreanu, Lorina
2015-01-01
Specifying and interpreting temporal constraints are key elements of knowledge representation and reasoning, with applications in temporal databases, agent programming, and ambient intelligence. We present and formally characterize the language CG, which tackles this issue. In CG, users are able to develop time-dependent programs, in a flexible and straightforward manner. Such programs can, in turn, be coupled with evolving environments, thus empowering users to control the environment's evolution. CG relies on a structure for storing temporal information, together with a dedicated query mechanism. Hence, we explore the computational complexity of our query satisfaction problem. We discuss previous implementation attempts of CG and introduce a novel prototype which relies on logic programming. Finally, we address the issue of consistency and correctness of CG program execution, using the Event-B modeling approach.
Identifying Social Satisfaction from Social Media
Bai, Shuotian; Gao, Rui; Hao, Bibo; Yuan, Sha; Zhu, Tingshao
2014-01-01
We demonstrate the critical need to identify social situation and instability factors by acquiring public social satisfaction in this research. However, subject to the large amount of manual work cost in subject recruitment and data processing, conventional self-reported method cannot be implemented in real time or applied in large scale investigation. To solve the problem, this paper proposed an approach to predict users' social satisfaction, especially for the economy-related satisfaction b...
Analysis of job satisfaction of employees
Procházka, Lukáš
2011-01-01
This thesis examines the problem of job satisfaction. It explains basic concepts and methods of most widely used theories of job satisfaction. The work contains survey on job satisfaction on a specific market entity - the company Telefónica Czech Republic, a.s., the findings of current situation and it proposes alternative procedures to improve the situation. Data collection was performed using a questionnaire submitted by employees of the company Telefónica Czech Republic, a. s. On the basis...
Some cosmological constraints on gauge theories
International Nuclear Information System (INIS)
Schramm, D.N.
1983-01-01
In these lectures, a review is made of various constraints cosmology may place on gauge theories. Particular emphasis is placed on those constraints obtainable from Big Bang Nucleosynthesis, with only brief mention made of Big Bang Baryosynthesis. There is also a considerable discussion of astrophysical constraints on masses and lifetimes of neutrinos with specific mention of the 'missing mass (light)' problem of galactic dynamics. (orig./HSI)
Job satisfaction, work ability and life satisfaction among Finnish anaesthesiologists.
Lindfors, P M; Meretoja, O A; Töyry, S M; Luukkonen, R A; Elovainio, M J; Leino, T J
2007-08-01
Organizational changes and relative growth of the ageing population together with related health problems seem to have increased stressfulness in the work of anaesthesiologists. However, little is known about their work-related well-being and the factors through which their situation could be improved. A cross-sectional questionnaire study of the level and the determinants of job satisfaction, work ability and life satisfaction among female and male anaesthesiologists involved 258 Finnish anaesthesiologists working full time (53% men). The respondents had fairly high job satisfaction, work ability and life satisfaction. No gender differences appeared in these well-being indicators, but their determinants differed by gender. Job satisfaction was only associated with work-related factors in both genders: with job control in women and with job control and organizational justice in men. Work ability correlated with job control and health in both genders and with family life in women. Life satisfaction correlated with individual- and family related factors such as social support and family problems in both genders. Life satisfaction correlated with physical workload in men and health in women. Women had less job control, fewer permanent job contracts and more domestic workload than men. Job control and organizational justice were the most important determinants in work-related well-being. Work-related factors were slightly more important correlates of well-being in males, and family life seems to play a larger role in the well-being of female anaesthesiologists. Organizational and gender issues need to be addressed in order to maintain a high level of well-being among anaesthesiologists.
International Nuclear Information System (INIS)
Fergusson, C.L.; Phillips, D.
2001-01-01
Four slate samples from subduction complex rocks exposed on the south coast of New South Wales, south of Batemans Bay, were analysed by K-Ar and 40 Ar/ 39 Ar step-heating methods, One sample contains relatively abundant detrital muscovite flakes that are locally oblique to the regional cleavage in the rock, whereas the remaining samples appear to contain sparse detrital muscovite. Separates of detrital muscovite yielded plateau ages of 505 + 3 Ma and 513 + 3 Ma indicating that inheritance has not been eliminated by metamorphism and recrystallisation. Step-heating analyses of whole-rock chips from all four slate samples produced discordant apparent age spectra with 'saddle shapes' following young apparent ages at the lowest temperature increments. Elevated apparent ages associated with the highest temperature steps are attributed to the presence of variable quantities of detrital muscovite ( 40 Ar/ 39 Ar integrated ages of ca 455Ma, which are some 15-30 million years older than K-Ar ages for the same samples. These discrepancies suggest that the slates have also been affected by recoil loss/redistribution of 39 Ar, Ieading to anomalously old 40 Ar/ 39 Ar ages. Two other samples, from slaty tectonic melange and intensely cleaved slate, yielded average 40 Ar/ 39 Ar integrated ages of ca 424Ma, which are closer to associated mean K-Ar ages of 423 + 4Ma and 409 + 16Ma, respectively. Taking into account the potential influences of recoil loss/redistribution of 39 Ar and inheritance, the results from the latter samples suggest a maximum age of ca 440 Ma for deformation/metamorphism. The current results indicate that recoil and inheritance problems may also have affected whole-rock 40 Ar/ 39 Ar data reported from other regions of the Lachlan Fold Belt. Therefore, until these effects are adequately quantified, models for the evolution of the Lachlan Fold Belt, that are based on such whole-rock 40 Ar/ 39 Ar data, should be treated with caution. Copyright (2001) Geological
Optimal Portfolio Choice with Wash Sale Constraints
DEFF Research Database (Denmark)
Astrup Jensen, Bjarne; Marekwica, Marcel
2011-01-01
We analytically solve the portfolio choice problem in the presence of wash sale constraints in a two-period model with one risky asset. Our results show that wash sale constraints can heavily affect portfolio choice of investors with unrealized losses. The trading behavior of such investors...
Work Hours Constraints: Impacts and Policy Implications
Constant, Amelie F.; Otterbach, Steffen
2011-01-01
If individuals reveal their preference as consumers, then they are taken seriously. What happens if individuals, as employees, reveal their preferences in working hours? And what happens if there is a misalignment between actual hours worked and preferred hours, the so-called work hours constraints? How does this affect the productivity of workers, their health, and overall life satisfaction? Labor supply and corresponding demand are fundamental to production. Labor economists know for long t...
Generalized Pauli constraints in small atoms
DEFF Research Database (Denmark)
Schilling, Christian; Altunbulak, Murat; Knecht, Stefan
2018-01-01
investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system......'s qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While...
Toward an automaton Constraint for Local Search
Directory of Open Access Journals (Sweden)
Jun He
2009-10-01
Full Text Available We explore the idea of using finite automata to implement new constraints for local search (this is already a successful technique in constraint-based global search. We show how it is possible to maintain incrementally the violations of a constraint and its decision variables from an automaton that describes a ground checker for that constraint. We establish the practicality of our approach idea on real-life personnel rostering problems, and show that it is competitive with the approach of [Pralong, 2007].
International Nuclear Information System (INIS)
Phillips, D.; Fergusson, C.L.
1999-01-01
mellange and intensely cleaved slate have been analysed and have 40 Ar/ 39 Ar integrated ages of 422 ± 2 Ma (K/Ar: 424 ± 5 Ma) and 415 ± 2 Ma (K/Ar: 400 ± 5 Ma). The general consistency of these results accompanied by microstructural observation indicating a low abundance of detrital mica, show that in these samples recoil and inheritance problems appear to be less important. Thus they provide a more reliable upper constraint on the timing the regional deformation on the south coast of New South Wales, i.e. younger than ca. 420 Ma, consistent with previously recognised regional structural constraints. Elsewhere in the Lachlan Fold Belt 40 Ar/ 39 Ar ages on fine-grained slates have been used to provide concise constraints on the timing of deformation. The current results raise serious questions about the interpretation of these ages as representing on-going deformation and therefore tectonic models derived from these data should be treated with caution. Copyright (1999) Geological Society of Australia
A Hybrid Soft Computing Approach for Subset Problems
Directory of Open Access Journals (Sweden)
Broderick Crawford
2013-01-01
Full Text Available Subset problems (set partitioning, packing, and covering are formal models for many practical optimization problems. A set partitioning problem determines how the items in one set (S can be partitioned into smaller subsets. All items in S must be contained in one and only one partition. Related problems are set packing (all items must be contained in zero or one partitions and set covering (all items must be contained in at least one partition. Here, we present a hybrid solver based on ant colony optimization (ACO combined with arc consistency for solving this kind of problems. ACO is a swarm intelligence metaheuristic inspired on ants behavior when they search for food. It allows to solve complex combinatorial problems for which traditional mathematical techniques may fail. By other side, in constraint programming, the solving process of Constraint Satisfaction Problems can dramatically reduce the search space by means of arc consistency enforcing constraint consistencies either prior to or during search. Our hybrid approach was tested with set covering and set partitioning dataset benchmarks. It was observed that the performance of ACO had been improved embedding this filtering technique in its constructive phase.
Portfolios with nonlinear constraints and spin glasses
Gábor, Adrienn; Kondor, I.
1999-12-01
In a recent paper Galluccio, Bouchaud and Potters demonstrated that a certain portfolio problem with a nonlinear constraint maps exactly onto finding the ground states of a long-range spin glass, with the concomitant nonuniqueness and instability of the optimal portfolios. Here we put forward geometric arguments that lead to qualitatively similar conclusions, without recourse to the methods of spin glass theory, and give two more examples of portfolio problems with convex nonlinear constraints.
Directory of Open Access Journals (Sweden)
Flávio Lopes Rodrigues
2003-10-01
Full Text Available Este trabalho teve como objetivos desenvolver e testar um algoritmo com base na metaheurística busca tabu (BT, para a solução de problemas de gerenciamento florestal com restrições de inteireza. Os problemas avaliados tinham entre 93 e 423 variáveis de decisão, sujeitos às restrições de singularidade, produção mínima e produção máxima periódicas. Todos os problemas tiveram como objetivo a maximização do valor presente líquido. O algoritmo para implementação da BT foi codificado em ambiente delphi 5.0 e os testes foram efetuados em um microcomputador AMD K6II 500 MHZ, com memória RAM de 64 MB e disco rígido de 15GB. O desempenho da BT foi avaliado de acordo com as medidas de eficácia e eficiência. Os diferentes valores ou categorias dos parâmetros da BT foram testados e comparados quanto aos seus efeitos na eficácia do algoritmo. A seleção da melhor configuração de parâmetros foi feita com o teste L&O, a 1% de probabilidade, e as análises através de estatísticas descritivas. A melhor configuração de parâmetros propiciou à BT eficácia média de 95,97%, valor mínimo igual a 90,39% e valor máximo igual a 98,84%, com um coeficiente de variação de 2,48% do ótimo matemático. Para o problema de maior porte, a eficiência da BT foi duas vezes superior à eficiência do algoritmo exato branch and bound, apresentando-se como uma abordagem muito atrativa para solução de importantes problemas de gerenciamento florestal.This work aimed to develop and test an algorithm based on Tabu Search (TS metaheuristics; to solve problems of forest management with integer constraints. TS was tested in five problems containing between 12 and 423 decision variables subjected to singularity constraints, minimum and maximum periodic productions. All the problems aimed at maximizing the net present value. TS was codified into delphi 5.0 language and the tests were performed in a microcomputer AMD K6II 500 MHZ, RAM memory 64 MB
Directory of Open Access Journals (Sweden)
Flávio Lopes Rodrigues
2004-04-01
Full Text Available Os objetivos deste trabalho foram desenvolver e testar a metaheurística SA para solução de problemas de gerenciamento florestal com restrições de integridade. O algoritmo SA desenvolvido foi testado em quatro problemas, contendo entre 93 e 423 variáveis de decisão, sujeitos às restrições de singularidade, produção mínima e produção máxima, periodicamente. Todos os problemas tiveram como objetivo a maximização do valor presente líquido. O algoritmo SA foi codificado em liguagem delphi 5.0 e os testes foram efetuados em um microcomputador AMD K6II 500 MHZ, com memória RAM de 64 MB e disco rígido de 15GB. O desempenho da SA foi avaliado de acordo com as medidas de eficácia e eficiência. Os diferentes valores ou categorias dos parâmetros da SA foram testados e comparados quanto aos seus efeitos na eficácia do algoritmo. A seleção da melhor configuração de parâmetros foi feita com o teste L&O, a 1% de probabilidade, e as análises foram realizadas através de estatísticas descritivas. A melhor configuração de parâmetros propiciou à SA eficácia média de 95,36%, valor mínimo de 83,66%, valor máximo de 100% e coeficiente de variação igual a 3,18% do ótimo matemático obtido pelo algoritmo exato branch and bound. Para o problema de maior porte, a eficiência da SA foi dez vezes superior à eficiência do algoritmo exato branch and bound. O bom desempenho desta heurística reforçou as conclusões, tiradas em outros trabalhos, do seu enorme potencial para resolver importantes problemas de gerenciamento florestal de difícil solução pelos instrumentos computacionais da atualidade.The objectives of this work was to develop and test an algorithm based on Simulated Annealing (SA metaheuristic to solve problems of forest management with integer constraints. The algorithm SA developed was tested in five problems containing between 93 and 423 decision variables, periodically subject to singularity constraints, minimum
Directory of Open Access Journals (Sweden)
Flávio Lopes Rodrigues
2004-04-01
Full Text Available Os objetivos deste trabalho foram desenvolver e testar um algoritmo genético (AG para a solução de problemas de gerenciamento florestal com restrições de integridade. O AG foi testado em quatro problemas, contendo entre 93 e 423 variáveis de decisão, sujeitos às restrições de singularidade, produção mínima e produção máxima, periodicamente. Todos os problemas tiveram como objetivo a maximização do valor presente líquido. O AG foi codificado em ambiente delphi 5.0 e os testes foram realizados em um microcomputador AMD K6II 500 MHZ, com memória RAM de 64 MB e disco rígido de 15GB. O desempenho do AG foi avaliado de acordo com as medidas de eficácia e eficiência. Os valores ou categorias dos parâmetros do AG foram testados e comparados quanto aos seus efeitos na eficácia do algoritmo. A seleção da melhor configuração de parâmetros foi feita com o teste L&O, a 1% de probabilidade, e as análises foram realizadas através de estatísticas descritivas. A melhor configuração de parâmetros propiciou ao AG eficácia média de 94,28%, valor mínimo de 90,01%, valor máximo de 98,48%, com coeficiente de variação de 2,08% do ótimo matemático, obtido pelo algoritmo exato branch and bound. Para o problema de maior porte, a eficiência do AG foi cinco vezes superior à eficiência do algoritmo exato branch and bound. O AG apresentou-se como uma abordagem bastante atrativa para solução de importantes problemas de gerenciamento florestal.The objectives of this work was to develop and test a Genetic Algorithm (GA to solve problems of forest management with integer constraints. GA was tested in five problems containing 93 - 423 decision variables, periodically subject to singularity constraints, minimum and maximum production. The problems had the objective of maximizing the net present value. GA was codified into delphi 5.0 language and the tests were performed in a microcomputer AMD K6II 500 MHZ, with RAM memory of 64 MB
Apollo 15 mare volcanism: constraints and problems
International Nuclear Information System (INIS)
Delano, J.W.
1985-01-01
The Apollo 15 landing site contains more volcanics in the form of crystalline basalts and pristine glasses, which form the framework for all models dealing with the mantle beneath that site. Major issues on the petrology of the mare source regions beneath that portion of Mare Imbrium are summarized
Constraint interface preconditioning for topology optimization problems
Czech Academy of Sciences Publication Activity Database
Kočvara, Michal; Loghin, D.; Turner, J.
2016-01-01
Roč. 38, č. 1 (2016), A128-A145 ISSN 1064-8275 R&D Projects: GA AV ČR IAA100750802 Grant - others:European Commission - EC(XE) 313781 Institutional support: RVO:67985556 Keywords : topology optimization * domain decomposition * Newton-Krylov Subject RIV: BA - General Mathematics Impact factor: 2.195, year: 2016 http://library.utia.cas.cz/separaty/2016/MTR/kocvara-0460325.pdf
Information problems and deposit constraints at banks
Jith Jayaratne; Donald Morgan
1997-01-01
Following the investment-cash flow literature, we test whether bank lending is constrained by the availability of insured deposits--a necessary condition for the existence of bank lending channel of monetary policy. We treat insured deposits as a type of "internal fund," similar to cash flows. We use a simple model to sort out the possible identification issues in interpreting a lending-deposit correlation, including reverse causality and omitted variable bias. To minimize the latter, we spli...
Infrared Constraint on Ultraviolet Theories
Energy Technology Data Exchange (ETDEWEB)
Tsai, Yuhsin [Cornell Univ., Ithaca, NY (United States)
2012-08-01
While our current paradigm of particle physics, the Standard Model (SM), has been extremely successful at explaining experiments, it is theoretically incomplete and must be embedded into a larger framework. In this thesis, we review the main motivations for theories beyond the SM (BSM) and the ways such theories can be constrained using low energy physics. The hierarchy problem, neutrino mass and the existence of dark matter (DM) are the main reasons why the SM is incomplete . Two of the most plausible theories that may solve the hierarchy problem are the Randall-Sundrum (RS) models and supersymmetry (SUSY). RS models usually suffer from strong flavor constraints, while SUSY models produce extra degrees of freedom that need to be hidden from current experiments. To show the importance of infrared (IR) physics constraints, we discuss the flavor bounds on the anarchic RS model in both the lepton and quark sectors. For SUSY models, we discuss the difficulties in obtaining a phenomenologically allowed gaugino mass, its relation to R-symmetry breaking, and how to build a model that avoids this problem. For the neutrino mass problem, we discuss the idea of generating small neutrino masses using compositeness. By requiring successful leptogenesis and the existence of warm dark matter (WDM), we can set various constraints on the hidden composite sector. Finally, to give an example of model independent bounds from collider experiments, we show how to constrain the DM–SM particle interactions using collider results with an effective coupling description.
Adjunct Faculty Job Satisfaction in California Community Colleges: A Narrative Inquiry
Nagle, Tonya
2016-01-01
The problem addressed in the qualitative narrative inquiry is the perceived level of adjunct faculty job satisfaction. The general problem is the inconclusive and contradictory information on job satisfaction for adjuncts nationwide. The specific problem is poor job satisfaction for adjunct faculty in California where adjuncts are 48% of the…
Low-cost design of next generation SONET/SDH networks with multiple constraints
CSIR Research Space (South Africa)
Karem, TR
2007-07-01
Full Text Available on constraints programming satisfaction technology is proposed. The algorithm is tested in OPNET simulation environment using different network models derived from a hypothetical case study of an optical network design for Bellville area in Cape Town, South...
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available We consider the problem of minimizing a convex separable logarithmic function over a region defined by a convex inequality constraint or linear equality constraint, and two-sided bounds on the variables (box constraints. Such problems are interesting from both theoretical and practical point of view because they arise in some mathematical programming problems as well as in various practical problems such as problems of production planning and scheduling, allocation of resources, decision making, facility location problems, and so forth. Polynomial algorithms are proposed for solving problems of this form and their convergence is proved. Some examples and results of numerical experiments are also presented.
Constraint programming for modelling and solving modal satisfiability
Brand, S.; Gennari, R.; de Rijke, M.
2003-01-01
We explore to what extent and how efficiently constraint programmingcan be used in the context of automated reasoning for modal logics. We encode modal satisfiability problems as constraint satisfactionproblems with non-boolean domains, together with suitable constraints.Experiments show that the
RESEARCH ON HUMAN RESOURCES MOTIVATION AND SATISFACTION
Directory of Open Access Journals (Sweden)
Zoltan-Bela FARKAS
2014-06-01
Full Text Available Many research studies on the human resources performance of the educational system have proved that pupils/students’ educational success depends, to a high degree, on the level of human resource motivation, as well as on their degree of professional satisfaction. Teachers’ who show a high level of motivation, both intrinsic and extrinsic, invest more into their activity, are more creative and more efficient in problem solving. The paper debates the results of an empirical study regarding the influence of pre-university teachers’ motivation and satisfaction regarding the general work conditions on their work performance by measuring the present motivation and satisfaction level. Furthermore, the determinant factors of their satisfaction with the work place are determined and analyzed. Finally, based on the statistical data process we will conclude and debate on the research hypothesis validation and the empirical model related to motivation – satisfaction – performance interdependences.
Ahmed, Najma; Conn, Lesley Gotlib; Chiu, Mary; Korabi, Bochra; Qureshi, Adnan; Nathens, Avery B; Kitto, Simon
2012-11-01
To understand what influences career satisfaction among general surgeons in urban and rural areas in Canada in order to improve recruitment and retention in general surgery. Semistructured interviews were conducted with 32 general surgeons in 2010 who were members of the Canadian Association of General Surgeons and who currently practice in either an urban or rural area. Interviews explored factors contributing to career satisfaction, as well as suggestions for preventive, screening, or management strategies to support general surgery practice. Findings revealed that both urban and rural general surgeons experienced the most satisfaction from their ability to resolve patient problems quickly and effectively, enhancing their sense of the meaningfulness of their clinical practice. The supportive relationships with colleagues, trainees, and patients was also cited as a key source of career satisfaction. Conversely, insufficient access to resources and a perceived disconnect between hospital administration and clinical practice priorities were raised as key "systems-level" problems. As a result, many participants felt alienated from their work by these systems-level barriers that were perceived to hinder the provision of high-quality patient care. Career satisfaction among both urban and rural general surgeons was influenced positively by the social aspects of their work, such as patient and colleague relationships, as well as a perception of an increasing amount of control and autonomy over their professional commitments. The modern general surgeon values a balance between professional obligations and personal time that may be difficult to achieve given the current system constraints.
Toward making the constraint hypersurface an attractor in free evolution
International Nuclear Information System (INIS)
Fiske, David R.
2004-01-01
When constructing numerical solutions to systems of evolution equations subject to a constraint, one must decide what role the constraint equations will play in the evolution system. In one popular choice, known as free evolution, a simulation is treated as a Cauchy problem, with the initial data constructed to satisfy the constraint equations. This initial data are then evolved via the evolution equations with no further enforcement of the constraint equations. The evolution, however, via the discretized evolution equations introduce constraint violating modes at the level of truncation error, and these constraint violating modes will behave in a formalism dependent way. This paper presents a generic method for incorporating the constraint equations into the evolution equations so that the off-constraint dynamics are biased toward the constraint satisfying solutions
Edalati, L.; Khaki Sedigh, A.; Aliyari Shooredeli, M.; Moarefianpour, A.
2018-02-01
This paper deals with the design of adaptive fuzzy dynamic surface control for uncertain strict-feedback nonlinear systems with asymmetric time-varying output constraints in the presence of input saturation. To approximate the unknown nonlinear functions and overcome the problem of explosion of complexity, a Fuzzy logic system is combined with the dynamic surface control in the backstepping design technique. To ensure the output constraints satisfaction, an asymmetric time-varying Barrier Lyapunov Function (BLF) is used. Moreover, by applying the minimal learning parameter technique, the number of the online parameters update for each subsystem is reduced to 2. Hence, the semi-globally uniformly ultimately boundedness (SGUUB) of all the closed-loop signals with appropriate tracking error convergence is guaranteed. The effectiveness of the proposed control is demonstrated by two simulation examples.
University Course Timetabling using Constraint Programming
Directory of Open Access Journals (Sweden)
Hadi Shahmoradi
2017-03-01
Full Text Available University course timetabling problem is a challenging and time-consuming task on the overall structure of timetable in every academic environment. The problem deals with many factors such as the number of lessons, classes, teachers, students and working time, and these are influenced by some hard and soft constraints. The aim of solving this problem is to assign courses and classes to teachers and students, so that the restrictions are held. In this paper, a constraint programming method is proposed to satisfy maximum constraints and expectation, in order to address university timetabling problem. For minimizing the penalty of soft constraints, a cost function is introduced and AHP method is used for calculating its coefficients. The proposed model is tested on department of management, University of Isfahan dataset using OPL on the IBM ILOG CPLEX Optimization Studio platform. A statistical analysis has been conducted and shows the performance of the proposed approach in satisfying all hard constraints and also the satisfying degree of the soft constraints is on maximum desirable level. The running time of the model is less than 20 minutes that is significantly better than the non-automated ones.
Constraint-Muse: A Soft-Constraint Based System for Music Therapy
Hölzl, Matthias; Denker, Grit; Meier, Max; Wirsing, Martin
Monoidal soft constraints are a versatile formalism for specifying and solving multi-criteria optimization problems with dynamically changing user preferences. We have developed a prototype tool for interactive music creation, called Constraint Muse, that uses monoidal soft constraints to ensure that a dynamically generated melody harmonizes with input from other sources. Constraint Muse provides an easy to use interface based on Nintendo Wii controllers and is intended to be used in music therapy for people with Parkinson’s disease and for children with high-functioning autism or Asperger’s syndrome.
Approximate Compilation of Constraints into Multivalued Decision Diagrams
DEFF Research Database (Denmark)
Hadzic, Tarik; Hooker, John N.; O’Sullivan, Barry
2008-01-01
We present an incremental refinement algorithm for approximate compilation of constraint satisfaction models into multivalued decision diagrams (MDDs). The algorithm uses a vertex splitting operation that relies on the detection of equivalent paths in the MDD. Although the algorithm is quite gene...
Satisfaction and 'comparison sharing'
DEFF Research Database (Denmark)
Amilon, Anna
2009-01-01
the probability of satisfaction. Results show that comparison sharing impacts satisfaction for women, and that those women who share more equally than their peers are more likely to be satisfied, whereas comparison sharing has no influence on satisfaction for men. Also, parents are less likely to be satisfied...
Case manager satisfaction in public health.
Schutt, Russell K; Fawcett, Jacqueline; Gall, Gail B; Harrow, Brooke; Woodford, Mary Lou
2010-01-01
The purpose of this study was to examine correlates of case managers' satisfaction with their work, services, and service network and to identify connections to service performance and service costs. A decentralized public health program that exemplifies the trend toward more diverse clients and networked services. A mixed method design with 34 case managers. As hypothesized, the case managers' experiences with clients and the service network, and their service effectiveness, were associated with their satisfaction with their jobs and the services they provide. Satisfaction was also positively associated with more timely service delivery. These associations were explained in part by case managers' education and training. Case managers can achieve high levels of job and service satisfaction in outreach programs serving a diverse client population in a decentralized service network. Case managers' job and service satisfaction improves with reduced service problems and service delays and when case managers can devise work-arounds for persistent service problems. Using advanced practice nurses (APN) and providing more on-the-job training may increase case manager satisfaction with their jobs and the services they provide. Special efforts may be needed to prevent a decline in job satisfaction with years of experience.
Financing Constraints and Entrepreneurship
William R. Kerr; Ramana Nanda
2009-01-01
Financing constraints are one of the biggest concerns impacting potential entrepreneurs around the world. Given the important role that entrepreneurship is believed to play in the process of economic growth, alleviating financing constraints for would-be entrepreneurs is also an important goal for policymakers worldwide. We review two major streams of research examining the relevance of financing constraints for entrepreneurship. We then introduce a framework that provides a unified perspecti...
Temporal Concurrent Constraint Programming
DEFF Research Database (Denmark)
Nielsen, Mogens; Valencia Posso, Frank Dan
2002-01-01
The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...
Patient satisfaction with maxillofacial prosthesis. Literature review.
Goiato, Marcelo Coelho; Pesqueira, Aldiéris Alves; Ramos da Silva, Cristina; Gennari Filho, Humberto; Micheline Dos Santos, Daniela
2009-02-01
Obturators and facial prostheses are important not only in rehabilitation and aesthetics, but also in patient re-socialisation. The level of reintegration is directly related to the degree of satisfaction with rehabilitation. So, the maxillofacial prosthetics must provide patient satisfaction during treatment. This study aimed to search information in database and conduct a literature review on patient satisfaction with maxillofacial prosthesis. The problems experienced by these patients may decrease when specialists keep the patient on regular inspection. Rehabilitation through alloplasty or prosthetic restoration provides satisfactory conditions in aesthetics and well-being and reinstates individuals in familial and social environment.
Cyclic labellings with constraints at two distances
Leese, R; Noble, S D
2004-01-01
Motivated by problems in radio channel assignment, we consider the vertex-labelling of graphs with non-negative integers. The objective is to minimise the span of the labelling, subject to constraints imposed at graph distances one and two. We show that the minimum span is (up to rounding) a piecewise linear function of the constraints, and give a complete specification, together with associated optimal assignments, for trees and cycles.
Duan, Qianqian; Yang, Genke; Xu, Guanglin; Pan, Changchun
2014-01-01
This paper is devoted to develop an approximation method for scheduling refinery crude oil operations by taking into consideration the demand uncertainty. In the stochastic model the demand uncertainty is modeled as random variables which follow a joint multivariate distribution with a specific correlation structure. Compared to deterministic models in existing works, the stochastic model can be more practical for optimizing crude oil operations. Using joint chance constraints, the demand uncertainty is treated by specifying proximity level on the satisfaction of product demands. However, the joint chance constraints usually hold strong nonlinearity and consequently, it is still hard to handle it directly. In this paper, an approximation method combines a relax-and-tight technique to approximately transform the joint chance constraints to a serial of parameterized linear constraints so that the complicated problem can be attacked iteratively. The basic idea behind this approach is to approximate, as much as possible, nonlinear constraints by a lot of easily handled linear constraints which will lead to a well balance between the problem complexity and tractability. Case studies are conducted to demonstrate the proposed methods. Results show that the operation cost can be reduced effectively compared with the case without considering the demand correlation.
Directory of Open Access Journals (Sweden)
Qianqian Duan
2014-01-01
Full Text Available This paper is devoted to develop an approximation method for scheduling refinery crude oil operations by taking into consideration the demand uncertainty. In the stochastic model the demand uncertainty is modeled as random variables which follow a joint multivariate distribution with a specific correlation structure. Compared to deterministic models in existing works, the stochastic model can be more practical for optimizing crude oil operations. Using joint chance constraints, the demand uncertainty is treated by specifying proximity level on the satisfaction of product demands. However, the joint chance constraints usually hold strong nonlinearity and consequently, it is still hard to handle it directly. In this paper, an approximation method combines a relax-and-tight technique to approximately transform the joint chance constraints to a serial of parameterized linear constraints so that the complicated problem can be attacked iteratively. The basic idea behind this approach is to approximate, as much as possible, nonlinear constraints by a lot of easily handled linear constraints which will lead to a well balance between the problem complexity and tractability. Case studies are conducted to demonstrate the proposed methods. Results show that the operation cost can be reduced effectively compared with the case without considering the demand correlation.
A compendium of chameleon constraints
International Nuclear Information System (INIS)
Burrage, Clare; Sakstein, Jeremy
2016-01-01
The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.
A compendium of chameleon constraints
Energy Technology Data Exchange (ETDEWEB)
Burrage, Clare [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Sakstein, Jeremy, E-mail: clare.burrage@nottingham.ac.uk, E-mail: jeremy.sakstein@port.ac.uk [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, 209 S. 33rd St., Philadelphia, PA 19104 (United States)
2016-11-01
The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.
Temporal Concurrent Constraint Programming
DEFF Research Database (Denmark)
Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan
2002-01-01
The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...
DEFF Research Database (Denmark)
Michelsen, Aage U.
2004-01-01
Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....
An adaptive ES with a ranking based constraint handling strategy
Directory of Open Access Journals (Sweden)
Kusakci Ali Osman
2014-01-01
Full Text Available To solve a constrained optimization problem, equality constraints can be used to eliminate a problem variable. If it is not feasible, the relations imposed implicitly by the constraints can still be exploited. Most conventional constraint handling methods in Evolutionary Algorithms (EAs do not consider the correlations between problem variables imposed by the constraints. This paper relies on the idea that a proper search operator, which captures mentioned implicit correlations, can improve performance of evolutionary constrained optimization algorithms. To realize this, an Evolution Strategy (ES along with a simplified Covariance Matrix Adaptation (CMA based mutation operator is used with a ranking based constraint-handling method. The proposed algorithm is tested on 13 benchmark problems as well as on a real life design problem. The outperformance of the algorithm is significant when compared with conventional ES-based methods.
Customer satisfaction research
Energy Technology Data Exchange (ETDEWEB)
Tormasi, T
1987-03-01
A review of four aspects of the Gas and Fuel Corporation of Victoria's study of customer satisfaction covers: (1) corporate goals to meet its responsibility as a public utility and operate as a successful marketing organization, (2) the history of customer satisfaction research by GFC, (3) measurements of customer satisfaction through expectations research, and (4) case studies involving domestic appliance maintenance and gas mains renewal. Continuous validation of GFC's policies and procedures is the basis for future growth and success. 3 tables.
Improving customer satisfaction
Wei, Yu
2011-01-01
Today, the competition among enterprises is growing in intensity and organizations of all types and sizes have increasingly come to understand the importance of customer satisfaction and good services. The purpose of this study is to investigate the present level of customer satisfaction with language training institutes and find out any possible areas of improvement. This thesis will discuss and analyze the factors that influence the customer’s level of satisfaction and assist the case compa...
Analysis of approaches to the concept of job satisfaction
Lysova E.
2017-01-01
the article is devoted the problem of satisfaction of person with his professional activities. It examines different approaches to understanding the phenomenon of job satisfaction, the analysis of their evolution in the works of domestic and Western scholars, describes the strengths and weaknesses of different interpretations of the concept of satisfaction. Almost a third of his life a person spends at work. In the labour force, he reveals himself as a person, implements the physical and ment...
Management Satisfaction Survey
Office of Personnel Management — The Chief Human Capital Officers' Managers' Satisfaction Survey asks managers to rate their perception of workforce planning, interaction with and levels of support...
[Nurses' professional satisfaction].
Del Cura, M L; Rodrigues, A R
1999-10-01
We carried out a study with 91 nurses, trying to find out about the feelings of these professionals regarding their satisfaction at work. We used the Work Satisfaction Assessment Questionnaire (WSAQ), drawn up and validated by Siqueira (1978) and adapted with the analysis of seven factors: General Satisfaction; Physical and Psychological Stress; "Status" of the Job; Location of the Company; Compensating Benefits; Recognition and Personal Development. Data showed nurses satisfied with their work, in its intrinsic aspects (Accomplishment, Recognition and Autonomy). The psychiatric nurses were the most mature, most experienced, showing a higher satisfaction level, whereas the pediatric nurses were the youngest, most inexperienced and presenting the highest level of dissatisfaction at work.
Resources, constraints and capabilities
Dhondt, S.; Oeij, P.R.A.; Schröder, A.
2018-01-01
Human and financial resources as well as organisational capabilities are needed to overcome the manifold constraints social innovators are facing. To unlock the potential of social innovation for the whole society new (social) innovation friendly environments and new governance structures
Design with Nonlinear Constraints
Tang, Chengcheng
2015-01-01
. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application
Route constraints model based on polychromatic sets
Yin, Xianjun; Cai, Chao; Wang, Houjun; Li, Dongwu
2018-03-01
With the development of unmanned aerial vehicle (UAV) technology, the fields of its application are constantly expanding. The mission planning of UAV is especially important, and the planning result directly influences whether the UAV can accomplish the task. In order to make the results of mission planning for unmanned aerial vehicle more realistic, it is necessary to consider not only the physical properties of the aircraft, but also the constraints among the various equipment on the UAV. However, constraints among the equipment of UAV are complex, and the equipment has strong diversity and variability, which makes these constraints difficult to be described. In order to solve the above problem, this paper, referring to the polychromatic sets theory used in the advanced manufacturing field to describe complex systems, presents a mission constraint model of UAV based on polychromatic sets.
Analyzing Food-Related Life Satisfaction and other Predictors of Life Satisfaction in Central Chile.
Schnettler, Berta; Lobos, Germán; Orellana, Ligia; Grunert, Klaus; Sepúlveda, José; Mora, Marcos; Denegri, Marianela; Miranda, Horacio
2015-06-17
This study aimed to assess the effect of satisfaction with food-related life on life satisfaction among inhabitants of the main municipalities of central Chile. A survey was applied to a sample of 1,277 people, distributed proportionally by municipality. The questionnaire included the following scales: SWLS (Satisfaction with Life Scale), SWFL (Satisfaction with Food-related Life) and the Health-Related Quality of Life Index (HRQOL). Questions were asked regarding eating habits inside and outside the home, time available for meals at home, the assessment of five sources of happiness and the demographic characteristics of those surveyed. An ordered logit model was proposed, in which the dependent variable was satisfaction with life. Satisfaction with life was significantly related to the respondent's socioeconomic status, self-perception of health, degree of satisfaction with food-related life, monthly food expenditure, time available for supper with the family (p health problems, frequency of supper with the family, the degree of agreement with respect to family being an important source of happiness (p food consumption in fast food outlets (p health, family and eating, and the family interaction associated with eating may play an important role in overall satisfaction with life.
Momentum constraint relaxation
International Nuclear Information System (INIS)
Marronetti, Pedro
2006-01-01
Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly
International Nuclear Information System (INIS)
Sugier, A.
2003-01-01
The selected new constraints should be consistent with the scale of concern i.e. be expressed roughly as fractions or multiples of the average annual background. They should take into account risk considerations and include the values of the currents limits, constraints and other action levels. The recommendation is to select four leading values for the new constraints: 500 mSv ( single event or in a decade) as a maximum value, 0.01 mSv/year as a minimum value; and two intermediate values: 20 mSv/year and 0.3 mSv/year. This new set of dose constraints, representing basic minimum standards of protection for the individuals taking into account the specificity of the exposure situations are thus coherent with the current values which can be found in ICRP Publications. A few warning need however to be noticed: There is no more multi sources limit set by ICRP. The coherence between the proposed value of dose constraint (20 mSv/year) and the current occupational dose limit of 20 mSv/year is valid only if the workers are exposed to one single source. When there is more than one source, it will be necessary to apportion. The value of 1000 mSv lifetimes used for relocation can be expressed into annual dose, which gives approximately 10 mSv/year and is coherent with the proposed dose constraint. (N.C.)
Poyrazli, Senel; Yesilyaprak, Binnur; Milliogullari, Ali
2012-01-01
Problem Statement: A review of the literature indicated that both job satisfaction and life satisfaction are important to an individual's overall wellbeing. While there have been extensive studies related to job satisfaction in a Turkish context, studies related to the predictors of life satisfaction are limited. Purpose of Study: The purpose of…
Navigating contextual constraints in discourse: Design explications in institutional talk
Herijgers, MLC (Marloes); Maat, HLW (Henk) Pander
2017-01-01
Although institutional discourse is subject to a vast ensemble of constraints, its design is not fixed beforehand. On the contrary, optimizing the satisfaction of these constraints requires considerable discourse design skills from institutional agents. In this article, we analyze how Dutch banks’ mortgage advisors navigate their way through the consultations context. We focus on what we call discourse design explications, that is, stretches of talk in which participants refer to conflicting constraints in the discourse context, at the same time proposing particular discourse designs for dealing with these conflicts. We start by discussing three forms of design explication. Then we will examine the various resolutions they propose for constraint conflicts and show how advisors seek customer consent or cooperation for the proposed designs. Thus our analysis reveals how institutional agents, while providing services, work on demonstrating how the design of these services is optimized and tailored to customers. PMID:28781580
Designing satisfaction studies
DEFF Research Database (Denmark)
Kristensen, Kai; Eskildsen, Jacob Kjær
2007-01-01
In the effect sampling method, presentation of researcher, the intro text, the order of questions in the questionnaire along with the number of categories in the rating scale is tested in relation to the design of satisfaction studies. Based on the analyses specific recommendations for designing...... satisfaction studies are given....
Customer satisfaction measurement
Directory of Open Access Journals (Sweden)
Maričić Branko R.
2012-01-01
Full Text Available Customer satisfaction is important in business management as a basis for long-term profitability of a single line of products and services and the company as a whole. Customer satisfaction in modern market conditions is characterized by a large number of alternatives that can satisfy the same need or desire of consumers, and are a prerequisite for the retention, loyalty, and positive verbal communication between companies and vendors on one hand and consumers on the other. Companies are investing more and more investment and management efforts in improving customer satisfaction. Improving customer satisfaction and its measurement involves the taking of appropriate marketing strategies and tactics, as well as corrective measures. This paper presents the well-known attempts to measure customers' satisfaction at the macro and micro level of marketing analysis. The index of consumer satisfaction is an important indicator of achieved quality and market performance of companies and can be measured on a micro and macro level. National customer satisfaction indexes are useful framework for analyzing the competitiveness of national economies, industries and individual companies and are used for a variety of other aspects of observation and analysis. Standardization of consumer satisfaction indexes in different countries allows comparability of the data, giving a new quality of analysis in the era of globalization and internationalization of business.
Measuring patient satisfaction.
Levin, Roger
2005-03-01
Many businesses use customer satisfaction surveys successfully. You may notice that you find one in almost every restaurant or hotel room. I do not think it is a coincidence that the hotel industry provides some of the finest customer service available. When it comes to providing excellent customer service, dental practices can learn from businesses that regularly assess customer satisfaction.
Misconceptions and constraints
International Nuclear Information System (INIS)
Whitten, M.; Mahon, R.
2005-01-01
In theory, the sterile insect technique (SIT) is applicable to a wide variety of invertebrate pests. However, in practice, the approach has been successfully applied to only a few major pests. Chapters in this volume address possible reasons for this discrepancy, e.g. Klassen, Lance and McInnis, and Robinson and Hendrichs. The shortfall between theory and practice is partly due to the persistence of some common misconceptions, but it is mainly due to one constraint, or a combination of constraints, that are biological, financial, social or political in nature. This chapter's goal is to dispel some major misconceptions, and view the constraints as challenges to overcome, seeing them as opportunities to exploit. Some of the common misconceptions include: (1) released insects retain residual radiation, (2) females must be monogamous, (3) released males must be fully sterile, (4) eradication is the only goal, (5) the SIT is too sophisticated for developing countries, and (6) the SIT is not a component of an area-wide integrated pest management (AW-IPM) strategy. The more obvious constraints are the perceived high costs of the SIT, and the low competitiveness of released sterile males. The perceived high up-front costs of the SIT, their visibility, and the lack of private investment (compared with alternative suppression measures) emerge as serious constraints. Failure to appreciate the true nature of genetic approaches, such as the SIT, may pose a significant constraint to the wider adoption of the SIT and other genetically-based tactics, e.g. transgenic genetically modified organisms (GMOs). Lack of support for the necessary underpinning strategic research also appears to be an important constraint. Hence the case for extensive strategic research in ecology, population dynamics, genetics, and insect behaviour and nutrition is a compelling one. Raising the competitiveness of released sterile males remains the major research objective of the SIT. (author)
Relationship between Teachers' Job Satisfaction and Students' Academic Performance
Iqbal, Asif; Aziz, Fakhra; Farooqi, Tahir Khan; Ali, Shabbir
2016-01-01
Problem Statement: An extensive literature on Job satisfaction has shown, teachers who are satisfied with their jobs perform better. Along with various indicators of teachers' job satisfaction, variables such as organizational justice (Nojani, Arjmandnia, Afrooz, & Rajabi, 2012), organizational culture (Hosseinkhanzadeh, Hosseinkhanzadeh,…
Leadership style and employees' intrinsic job satisfaction in the ...
African Journals Online (AJOL)
This study investigates the impact of leadership style on employees' intrinsic job satisfaction in the Cross River State Newspaper Corporation, Calabar, Nigeria. The study examined the problem of dissatisfaction in the work place as far as intrinsic factors of job satisfaction are concerned. Structured questionnaire was used ...
The Effect of Entrepreneurial Orientation on Teacher Satisfaction and Retention
Thibault, Melissa Rihm
2016-01-01
Teacher turnover is a costly problem. Since teacher working conditions influence teacher's satisfaction and career intentions, managers may theoretically increase teacher satisfaction and retention by fostering a school environment supportive of the highly-trained professional. Entrepreneurial Orientation is an organizational construct correlated…
Directory of Open Access Journals (Sweden)
Mariana Santos Matos Cavalca
2012-01-01
Full Text Available One of the main advantages of predictive control approaches is the capability of dealing explicitly with constraints on the manipulated and output variables. However, if the predictive control formulation does not consider model uncertainties, then the constraint satisfaction may be compromised. A solution for this inconvenience is to use robust model predictive control (RMPC strategies based on linear matrix inequalities (LMIs. However, LMI-based RMPC formulations typically consider only symmetric constraints. This paper proposes a method based on pseudoreferences to treat asymmetric output constraints in integrating SISO systems. Such technique guarantees robust constraint satisfaction and convergence of the state to the desired equilibrium point. A case study using numerical simulation indicates that satisfactory results can be achieved.
DEFF Research Database (Denmark)
Olsen, Asmus Leth
2015-01-01
This article introduces the importance of equivalence framing for understanding how satisfaction measures affect citizens’ evaluation of public services. Does a 90 percent satisfaction rate have a different effect than a logically equivalent 10 percent dissatisfaction rate? Two experiments were...... conducted on citizens’ evaluations of hospital services in a large, nationally representative sample of Danish citizens. Both experiments found that exposing citizens to a patient dissatisfaction measure led to more negative views of public service than exposing them to a logically equivalent satisfaction...... metric. There is some support for part of the shift in evaluations being caused by a negativity bias: dissatisfaction has a larger negative impact than satisfaction has a positive impact. Both professional experience at a hospital and prior exposure to satisfaction rates reduced the negative response...
Career satisfaction and burnout among Ghanaian physicians.
Opoku, Samuel T; Apenteng, Bettye A
2014-03-01
Thus far, there has been limited inquiry into the factors associated with physician career satisfaction and burnout in Ghana, although the two have been linked to the brain drain problem. The objective of this study was to assess career satisfaction and burnout among physicians practicing in a developing nation, Ghana. A 21-item instrument was used to assess career satisfaction among actively practicing Ghanaian physicians, using items adapted from the Physician Worklife Study survey. Burnout was assessed using the Abbreviated Maslach's Burnout Inventory. Two hundred physicians participated in the online survey from December 2012 to February 2013. Generally, physicians in Ghana expressed moderate overall career satisfaction. However, they were least satisfied with the availability of resources, their compensation and work-life balance. Overall, burnout was low in the study population; however physicians exhibited moderate levels of emotional exhaustion. Career satisfaction was negatively associated with the burnout dimensions of depersonalization, emotional exhaustion and low personal accomplishment. Health policy-makers in Ghana should address issues relating to resource adequacy, compensation and the work-life balance of physicians in order to improve the overall career satisfaction of an already dwindling physician workforce.
Factors that influence nurses' job satisfaction.
Ma, Chen-Chung; Samuels, Michael E; Alexander, Judith W
2003-05-01
To examine factors affecting the job satisfaction of registered nurses (RNs). A growing recognition of job dissatisfaction among RNs in South Carolina hospitals has contributed to current problems with recruitment and retention. If administrators identify factors influencing RNs' job satisfaction in hospitals and implement strategies to address these factors, RN turnover rates will decrease and recruiting and retention rates will increase. A cross-sectional study of secondary data was designed to identify the individual, work, and geographic factors that impact nursing job satisfaction at the state level. A 27-question self-administered survey was sent to 17,500 RNs in South Carolina with postage-paid envelopes for their responses. Surveys from 3472 nurses were completed anonymously. Univariate statistics were used to describe the study sample. One-way and multivariable Analysis of Variance were used to determine which variables contributed the most to job satisfaction. For about two thirds of the RNs, job satisfaction remained the same or had lessened over the past 2 years. In addition, statistically significant differences were found between job satisfaction and years of service, job position, hospital retirement plan, and geographic area. The findings have implications for nurse managers and hospital administrators for planning and implementing effective health policies that will meet the unique needs of their staffs and organizations. Such research is particularly relevant in this difficult time of nursing shortages throughout the healthcare industry.
Robust Utility Maximization Under Convex Portfolio Constraints
International Nuclear Information System (INIS)
Matoussi, Anis; Mezghani, Hanen; Mnif, Mohamed
2015-01-01
We study a robust maximization problem from terminal wealth and consumption under a convex constraints on the portfolio. We state the existence and the uniqueness of the consumption–investment strategy by studying the associated quadratic backward stochastic differential equation. We characterize the optimal control by using the duality method and deriving a dynamic maximum principle
Institutional and resource constraints that inhibit contractor ...
African Journals Online (AJOL)
Results show that contractors face institutional constraints (work allocation limitations, lack of performance incentives and high transaction costs, such as negotiation costs, the risk of a loss in work and contract default risk), cash flow problems, poor physical infrastructure and a lack of labour. It is expected that the promotion ...
Egalitarian Risk Sharing under Liquidity Constraints
Koster, M.; Boonen, T.
2014-01-01
Undertaking joint projects in practice involves a lot of uncertainty, especially when it comes to the final costs. This paper addresses the problem of sharing realized costs by the participants, subject to their indvidual liquidity constraints. If all cost levels can be accounted for, and it the
Tilapia culture in Kuwait: constraints and solutions
Ridha, M.T.
2006-01-01
Tilapia farming in Kuwait is in its early stages. Slow growth, high production cost and poor demand are the major constraints to the expansion of tilapia culture in Kuwait. This article presents some suggestions for overcoming these problems to improve the economic feasibility of tilapia culture in Kuwait.
Constraints on low energy Compton scattering amplitudes
International Nuclear Information System (INIS)
Raszillier, I.
1979-04-01
We derive the constraints and correlations of fairly general type for Compton scattering amplitudes at energies below photoproduction threshold and fixed momentum transfer, following from (an upper bound on) the corresponding differential cross section above photoproduction threshold. The derivation involves the solution of an extremal problem in a certain space of vector - valued analytic functions. (author)
Evaluating Direct Manipulation Operations for Constraint-Based Layout
Zeidler , Clemens; Lutteroth , Christof; Stuerzlinger , Wolfgang; Weber , Gerald
2013-01-01
Part 11: Interface Layout and Data Entry; International audience; Layout managers are used to control the placement of widgets in graphical user interfaces (GUIs). Constraint-based layout managers are more powerful than other ones. However, they are also more complex and their layouts are prone to problems that usually require direct editing of constraints. Today, designers commonly use GUI builders to specify GUIs. The complexities of traditional approaches to constraint-based layouts pose c...
Constraints and Logic Programming in Grammars and Language Analysis
DEFF Research Database (Denmark)
Christiansen, Henning
2014-01-01
Constraints are an important notion in grammars and language analysis, and constraint programming techniques have been developed concurrently for solving a variety of complex problems. In this chapter we consider the synthesis of these branches into practical and effective methods for language...... methods that combine constraints with logic grammars such as Definite Clause Grammars and CHR Grammars, and show also a direct relationship to abductive reasoning....
Directory of Open Access Journals (Sweden)
Lau Bjørn
2011-03-01
Full Text Available Abstract Objectives To address the relative importance of general job-related stressors, ambulance specific stressors and individual characteristics in relation to job satisfaction and health complaints (emotional exhaustion, psychological distress and musculoskeletal pain among ambulance personnel. Materials and methods A nationwide prospective questionnaire survey of ambulance personnel in operational duty at two time points (n = 1180 at baseline, T1 and n = 298 at one-year follow up, T2. The questionnaires included the Maslach Burnout Inventory, The Job Satisfaction Scale, Hopkins Symptom Checklist (SCL-10, Job Stress Survey, the Norwegian Ambulance Stress Survey and the Basic Character Inventory. Results Overall, 42 out of the possible 56 correlations between job stressors at T1 and job satisfaction and health complaints at T2 were statistically significant. Lower job satisfaction at T2 was predicted by frequency of lack of leader support and severity of challenging job tasks. Emotional exhaustion at T2 was predicted by neuroticism, frequency of lack of support from leader, time pressure, and physical demands. Adjusted for T1 levels, emotional exhaustion was predicted by neuroticism (beta = 0.15, p Psychological distress at T2 was predicted by neuroticism and lack of co-worker support. Adjusted for T1 levels, psychological distress was predicted by neuroticism (beta = 0.12, p Musculoskeletal pain at T2 was predicted by, higher age, neuroticism, lack of co-worker support and severity of physical demands. Adjusted for T1 levels, musculoskeletal pain was predicted neuroticism, and severity of physical demands (beta = 0.12, p Conclusions Low job satisfaction at T2 was predicted by general work-related stressors, whereas health complaints at T2 were predicted by both general work-related stressors and ambulance specific stressors. The personality variable neuroticism predicted increased complaints across all health outcomes.
International Nuclear Information System (INIS)
Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria
2005-01-01
The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography
Psychological constraints on egalitarianism
DEFF Research Database (Denmark)
Kasperbauer, Tyler Joshua
2015-01-01
processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what......Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...
Generalized Pauli constraints in small atoms
Schilling, Christian; Altunbulak, Murat; Knecht, Stefan; Lopes, Alexandre; Whitfield, James D.; Christandl, Matthias; Gross, David; Reiher, Markus
2018-05-01
The natural occupation numbers of fermionic systems are subject to nontrivial constraints, which include and extend the original Pauli principle. A recent mathematical breakthrough has clarified their mathematical structure and has opened up the possibility of a systematic analysis. Early investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system's qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While the results seem incompatible with the statement that the generalized Pauli constraints drive the behavior of these systems, they suggest that the qualitatively correct wave-function expansions can in some systems already be obtained on the basis of a limited number of Slater determinants, which is in line with numerical evidence from quantum chemistry.
Job satisfaction as a matter of time, team, and trust
DEFF Research Database (Denmark)
Uhrenfeldt, Lisbeth; Hall, Elisabeth
2015-01-01
Support and variety regarding work, autonomy, organizational constraints, and promotion opportunities are factors contributing to job satisfaction or lack thereof among hospital nurses together with self-perceived health, education and career orientation. The aim of this study was to explore public...... hospital nurses’ experiences of job satisfaction. This qualitative study was undertaken in a caring theory context. Ten proficient Danish hospital nurses were interviewed twice and data were analysed using a hermeneutic approach. The analysis revealed that time, team, and trust were essential components...... in job satisfaction. Time, team and trust helped the nurses collaborate with patients, care for relatives, and work in teams with other hospital staff members. Lack of job satisfaction occurred when time was to short or quality care was threatened, when the nurses felt alone and had to finish their job...
Survey of pay satisfaction, job satisfaction and employee turnover in ...
African Journals Online (AJOL)
Survey of pay satisfaction, job satisfaction and employee turnover in selected business organisations in Lagos, Nigeria. ... Global Journal of Social Sciences ... The study was an attempt at investigating the relatedness of pay satisfaction, job satisfaction and employee turnover in business organizations in Lagos Nigeria.
Optimal power allocation of a sensor node under different rate constraints
Ayala Solares, Jose Roberto; Rezki, Zouheir; Alouini, Mohamed-Slim
2012-01-01
The optimal transmit power of a sensor node while satisfying different rate constraints is derived. First, an optimization problem with an instantaneous transmission rate constraint is addressed. Next, the optimal power is analyzed, but now
Optimal Stopping with Information Constraint
International Nuclear Information System (INIS)
Lempa, Jukka
2012-01-01
We study the optimal stopping problem proposed by Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002). In this maximization problem of the expected present value of the exercise payoff, the underlying dynamics follow a linear diffusion. The decision maker is not allowed to stop at any time she chooses but rather on the jump times of an independent Poisson process. Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002), solve this problem in the case where the underlying is a geometric Brownian motion and the payoff function is of American call option type. In the current study, we propose a mild set of conditions (covering the setup of Dupuis and Wang in Adv. Appl. Probab. 34:141–157, 2002) on both the underlying and the payoff and build and use a Markovian apparatus based on the Bellman principle of optimality to solve the problem under these conditions. We also discuss the interpretation of this model as optimal timing of an irreversible investment decision under an exogenous information constraint.
The manifestation of job satisfaction in doctor-patient communication: a ten-country European study.
Bensing, J.M.; Brink-Muinen, A. van den; Boerma, W.; Dulmen, S. van
2013-01-01
Objective: Job satisfaction is a common problem in modern western health care. While a lot of studies analyzed the determinants of job (dis)satisfaction, less is known about the consequences of doctors’ job satisfaction for medical visits. The aim of this study is to examine - female and male -
On quantization of time-dependent systems with constraints
International Nuclear Information System (INIS)
Gadjiev, S A; Jafarov, R G
2007-01-01
The Dirac method of canonical quantization of theories with second-class constraints has to be modified if the constraints depend on time explicitly. A solution of the problem was given by Gitman and Tyutin. In the present work we propose an independent way to derive the rules of quantization for these systems, starting from the physical equivalent theory with trivial non-stationarity
On quantization of time-dependent systems with constraints
International Nuclear Information System (INIS)
Hadjialieva, F.G.; Jafarov, R.G.
1993-07-01
The Dirac method of canonical quantization of theories with second class constraints has to be modified if the constraints depend on time explicitly. A solution of the problem was given by Gitman and Tyutin. In the present work we propose an independent way to derive the rules of quantization for these systems, starting from physical equivalent theory with trivial nonstationarity. (author). 4 refs
On quantization of time-dependent systems with constraints
Energy Technology Data Exchange (ETDEWEB)
Gadjiev, S A; Jafarov, R G [Institute for Physical Problems, Baku State University, AZ11 48 Baku (Azerbaijan)
2007-03-30
The Dirac method of canonical quantization of theories with second-class constraints has to be modified if the constraints depend on time explicitly. A solution of the problem was given by Gitman and Tyutin. In the present work we propose an independent way to derive the rules of quantization for these systems, starting from the physical equivalent theory with trivial non-stationarity.
Top-k Based Adaptive Enumeration in Constraint Programming
Directory of Open Access Journals (Sweden)
Ricardo Soto
2015-01-01
order for variables and values is employed along the search. In this paper, we present a new and more lightweight approach for performing adaptive enumeration. We incorporate a powerful classification technique named Top-k in order to adaptively select strategies along the resolution. We report results on a set of well-known benchmarks where the proposed approach noticeably competes with classical and modern adaptive enumeration methods for constraint satisfaction.
Serious Leisure and People with Orthopedic Impairment: Benefits and Constraints
Manolya AKSATAN; Zehra Gökçe SEL
2017-01-01
There are many people around the world who have different types of disabilities. Understanding their needs is the first step of developing policies to increase their quality of life and satisfaction. Leisure is an essential need of disabled people and it plays an important role in disabled people’s lives. The purpose of this study is to gain a deep understanding on the serious leisure activities of people with orthopedic impairment, and also both benefits and constraints ...
International Nuclear Information System (INIS)
Alwis, S.P. de
2016-01-01
We discuss constraints on KKLT/KKLMMT and LVS scenarios that use anti-branes to get an uplift to a deSitter vacuum, coming from requiring the validity of an effective field theory description of the physics. We find these are not always satisfied or are hard to satisfy.
Ecosystems emerging. 5: Constraints
Czech Academy of Sciences Publication Activity Database
Patten, B. C.; Straškraba, Milan; Jorgensen, S. E.
2011-01-01
Roč. 222, č. 16 (2011), s. 2945-2972 ISSN 0304-3800 Institutional research plan: CEZ:AV0Z50070508 Keywords : constraint * epistemic * ontic Subject RIV: EH - Ecology, Behaviour Impact factor: 2.326, year: 2011 http://www.sciencedirect.com/science/article/pii/S0304380011002274
DEFF Research Database (Denmark)
Dove, Graham; Biskjær, Michael Mose; Lundqvist, Caroline Emilie
2017-01-01
groups of students building three models each. We studied groups building with traditional plastic bricks and also using a digital environment. The building tasks students undertake, and our subsequent analysis, are informed by the role constraints and ambiguity play in creative processes. Based...
Motoko Miyake; Ellen Rodgers
2009-01-01
This study investigated the relationship of motivation for and perceived constraints to physical activity (PA) participation and the well-being of senior center participants. A survey instrument made up of modified versions of the Sport Motivation and Perceived Constraints Scales, the Life Satisfaction Index-Z, and the Geriatric Depression Scale was administered at the...
Simulating non-holonomic constraints within the LCP-based simulation framework
DEFF Research Database (Denmark)
Ellekilde, Lars-Peter; Petersen, Henrik Gordon
2006-01-01
be incorporated directly, and derive formalism for how the non-holonomic contact constraints can be modelled as a combination of non-holonomic equality constraints and ordinary contacts constraints. For each of these three we are able to guarantee solvability, when using Lemke's algorithm. A number of examples......In this paper, we will extend the linear complementarity problem-based rigid-body simulation framework with non-holonomic constraints. We consider three different types of such, namely equality, inequality and contact constraints. We show how non-holonomic equality and inequality constraints can...... are included to demonstrate the non-holonomic constraints. Udgivelsesdato: Marts...
Nurses Returning to School: Motivators, Inhibitors and Job Satisfaction.
Harris, Patrick W; Burman, Mary E
2016-01-01
Health care employers and national nursing organizations are placing increased emphasis on nurses earning a baccalaureate degree or higher. This study examines the impact of motivators (professional and personal motivation), inhibitors (time constraints and employer discouragement), and job satisfaction on intent to return to school. Approximately half of the employed nurses in Wyoming were surveyed using a mailed questionnaire in the summer of 2013. Perceived employer discouragement and time constraints continued to play a direct role on intent to return to school regardless of nurse motivation or job satisfaction. However, motivation and job satisfaction also contributed to a nurse's intent to return to school. These results suggest that motivation and job satisfaction are significant regarding intent to return to school but can be limited by both perceived discouragement of one's employer and perceived time constraints. In order to meet the increasing demands of a better-educated nursing workforce, a shift in workplace dynamics may be warranted. Copyright © 2016 Elsevier Inc. All rights reserved.
A comparison of Heuristic method and Llewellyn’s rules for identification of redundant constraints
Estiningsih, Y.; Farikhin; Tjahjana, R. H.
2018-03-01
Important techniques in linear programming is modelling and solving practical optimization. Redundant constraints are consider for their effects on general linear programming problems. Identification and reduce redundant constraints are for avoidance of all the calculations associated when solving an associated linear programming problems. Many researchers have been proposed for identification redundant constraints. This paper a compararison of Heuristic method and Llewellyn’s rules for identification of redundant constraints.
African Journals Online (AJOL)
AmL
doctors and retention of the existing doctors, in addition to the ... an employee's well-being Examples of job resources are job ..... increase physician job satisfaction for ensuring the .... both pay and benefits physicians at private hospitals.
ASD Customer Satisfaction Survey
Department of Veterans Affairs — ASD implemented a customer satisfaction survey for our products and services. This feedback will provide a better understanding of how ASD products and services can...
Office of Personnel Management — The Chief Human Capital Officers developed 3 surveys that asks applicants to assess their satisfaction with the application process on a 1-10 point scale, with 10...
Management strategies to improve job satisfaction of principals in primary schools / Khumalo M.G.
Khumalo, Mapula Gertrude.
2012-01-01
The aim of this study is to optimise aspects of job satisfaction in the work environment to improve the effectiveness of primary school principals. Job dissatisfaction seems to be a worldwide problem in the education sector, even in South Africa a number of researches were conducted on job satisfaction. In this research the focus is on the following research questions: What is the nature of job satisfaction? Which factors contribute to the job satisfaction/dissatisfaction of primary school...
Customer satisfaction and business excellence
DEFF Research Database (Denmark)
Kristensen, Kai; Martensen, Anne; Grønholdt, Lars
The topic for this paper is the link between customer satisfaction and business performance, which makes it possible to use customer satisfaction measures as basis for creating business excellence. First, the paper presents microeconomic models for the relationship between customer satisfaction......, customer loyalty and performance, and optimal customer satisfaction is characterized which will help management choose the right quality parameters for improvement. Second, the paper describes empirical evidence that customer satisfaction measures, based on a modelling approach, have impact on economic...
Job Satisfaction of Nursing Managers
Petrosova, Liana; Pokhilenko, Irina
2015-01-01
The aim of the study was to research levels of job satisfaction, factors affecting job satisfaction/dissatisfaction, and ways to improve job satisfaction among nursing managers. The purposes of the study were to extend knowledge in the field of healthcare management, to raise awareness about factors that affect job satisfaction in nursing management career, and to provide suggestions regarding how to increase job satisfaction among nursing managers. The method of this study is literature r...
Lorentz violation. Motivation and new constraints
International Nuclear Information System (INIS)
Liberati, S.; Maccione, L.
2009-09-01
We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)
Lorentz violation. Motivation and new constraints
Energy Technology Data Exchange (ETDEWEB)
Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-09-15
We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)
Heidemeier, Heike; Staudinger, Ursula M.
2012-01-01
This study demonstrates how self-evaluation processes explain subgroup differences in ratings of life satisfaction (population heterogeneity). Life domains differ with regard to the constraints they impose on beliefs in internal control. We hypothesized that these differences are linked with cognitive biases in ratings of life satisfaction. In…
Cosmographic Constraints and Cosmic Fluids
Directory of Open Access Journals (Sweden)
Salvatore Capozziello
2013-12-01
Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.
Profit maximization with customer satisfaction control for electric vehicle charging in smart grids
Directory of Open Access Journals (Sweden)
Edwin Collado
2017-05-01
Full Text Available As the market of electric vehicles is gaining popularity, large-scale commercialized or privately-operated charging stations are expected to play a key role as a technology enabler. In this paper, we study the problem of charging electric vehicles at stations with limited charging machines and power resources. The purpose of this study is to develop a novel profit maximization framework for station operation in both offline and online charging scenarios, under certain customer satisfaction constraints. The main goal is to maximize the profit obtained by the station owner and provide a satisfactory charging service to the customers. The framework includes not only the vehicle scheduling and charging power control, but also the managing of user satisfaction factors, which are defined as the percentages of finished charging targets. The profit maximization problem is proved to be NPcomplete in both scenarios (NP refers to “nondeterministic polynomial time”, for which two-stage charging strategies are proposed to obtain efficient suboptimal solutions. Competitive analysis is also provided to analyze the performance of the proposed online two-stage charging algorithm against the offline counterpart under non-congested and congested charging scenarios. Finally, the simulation results show that the proposed two-stage charging strategies achieve performance close to that with exhaustive search. Also, the proposed algorithms provide remarkable performance gains compared to the other conventional charging strategies with respect to not only the unified profit, but also other practical interests, such as the computational time, the user satisfaction factor, the power consumption, and the competitive ratio.
Nurses' Job satisfaction: an Italian study.
Sansoni, J; De Caro, W; Marucci, A R; Sorrentino, M; Mayner, L; Lancia, L
2016-01-01
The aim of the work presented was to assess job satisfaction of a number of nurses from different departments working in public hospitals in Italy. The assessment was carried out through the combined use of questionnaires, which measured different aspects of job satisfaction, such as coping abilities, stress level and optimism/pessimism. The literature supports the fact that nurses' job dissatisfaction is closely connected with high levels of stress, burnout and physical and mental exhaustion, together with high workload levels and the complexity of care. The growing interest in measuring the levels of nurses' job satisfaction is attributable to a number of problems that have been raised worldwide, two of which are becoming ever so important: turnover and shortage of nurses. The research question is: Which are the main motivating factors of Italian nurses' job satisfaction/dissatisfaction? The study used a convenience (non probability) sample of 1,304 nurses from 15 different wards working in Italian public hospitals from a number of cities in northern, central and southern Italy. The survey instrument was a questionnaire consisting of 205 items which included 5 different questionnaires combined together. The results show a low level of job satisfaction (IWS= 11.5, JSS=126.4). However, the participants were overall happy about their job and considered autonomy and salary important factors for job satisfaction. Research has shown that the nurses' level of satisfaction in Italian hospitals is low. The results revealed dissatisfaction with task requirements, organizational policies and advance in career. Nurses interviewed did not feel stressed and showed to be optimistic overall. New research on the subject should be conducted by focusing on ward differences, North and South of Italy and on gender differences.
Mean-Reverting Portfolio With Budget Constraint
Zhao, Ziping; Palomar, Daniel P.
2018-05-01
This paper considers the mean-reverting portfolio design problem arising from statistical arbitrage in the financial markets. We first propose a general problem formulation aimed at finding a portfolio of underlying component assets by optimizing a mean-reversion criterion characterizing the mean-reversion strength, taking into consideration the variance of the portfolio and an investment budget constraint. Then several specific problems are considered based on the general formulation, and efficient algorithms are proposed. Numerical results on both synthetic and market data show that our proposed mean-reverting portfolio design methods can generate consistent profits and outperform the traditional design methods and the benchmark methods in the literature.
Faddeev-Jackiw quantization and constraints
International Nuclear Information System (INIS)
Barcelos-Neto, J.; Wotzasek, C.
1992-01-01
In a recent Letter, Faddeev and Jackiw have shown that the reduction of constrained systems into its canonical, first-order form, can bring some new insight into the research of this field. For sympletic manifolds the geometrical structure, called Dirac or generalized bracket, is obtained directly from the inverse of the nonsingular sympletic two-form matrix. In the cases of nonsympletic manifolds, this two-form is degenerated and cannot be inverted to provide the generalized brackets. This singular behavior of the sympletic matrix is indicative of the presence of constraints that have to be carefully considered to yield to consistent results. One has two possible routes to treat this problem: Dirac has taught us how to implement the constraints into the potential part (Hamiltonian) of the canonical Lagrangian, leading to the well-known Dirac brackets, which are consistent with the constraints and can be mapped into quantum commutators (modulo ordering terms). The second route, suggested by Faddeev and Jackiw, and followed in this paper, is to implement the constraints directly into the canonical part of the first order Lagrangian, using the fact that the consistence condition for the stability of the constrained manifold is linear in the time derivative. This algorithm may lead to an invertible two-form sympletic matrix from where the Dirac brackets are readily obtained. This algorithm is used in this paper to investigate some aspects of the quantization of constrained systems with first- and second-class constraints in the sympletic approach
Employee satisfaction and employee retention: catalysts to patient satisfaction.
Collins, Kevin S; Collins, Sandra K; McKinnies, Richard; Jensen, Steven
2008-01-01
Over the last few years, most health care facilities have become intensely aware of the need to increase patient satisfaction. However, with today's more consumer-driven market, this can be a daunting task for even the most experienced health care manager. Recent studies indicate that focusing on employee satisfaction and subsequent employee retention may be strong catalysts to patient satisfaction. This study offers a review of how employee satisfaction and retention correlate with patient satisfaction and also examines the current ways health care organizations are focusing on employee satisfaction and retention.
Energy constraints and organizational change in US production
Energy Technology Data Exchange (ETDEWEB)
1980-12-01
There is still considerable uncertainty about the way in which energy-supply constraints affect industrial thinking and activity. Yet, this is an important issue in determining the effectiveness of conservation programs and in formulating energy policy. The authors expand on a survey of US business attitudes and responses to energy constraints first published in the September 1979 Energy Policy with the results of further analysis of their survey. In particular, they examine correlations between perceived causes and preferred solutions of energy problems, organizational adjustments to energy constraints in energy-intensive industries, and the ways in which production operations have changed in response to supply problems. 5 references, 5 tables.
Distributed Unmixing of Hyperspectral Datawith Sparsity Constraint
Khoshsokhan, S.; Rajabi, R.; Zayyani, H.
2017-09-01
Spectral unmixing (SU) is a data processing problem in hyperspectral remote sensing. The significant challenge in the SU problem is how to identify endmembers and their weights, accurately. For estimation of signature and fractional abundance matrices in a blind problem, nonnegative matrix factorization (NMF) and its developments are used widely in the SU problem. One of the constraints which was added to NMF is sparsity constraint that was regularized by L1/2 norm. In this paper, a new algorithm based on distributed optimization has been used for spectral unmixing. In the proposed algorithm, a network including single-node clusters has been employed. Each pixel in hyperspectral images considered as a node in this network. The distributed unmixing with sparsity constraint has been optimized with diffusion LMS strategy, and then the update equations for fractional abundance and signature matrices are obtained. Simulation results based on defined performance metrics, illustrate advantage of the proposed algorithm in spectral unmixing of hyperspectral data compared with other methods. The results show that the AAD and SAD of the proposed approach are improved respectively about 6 and 27 percent toward distributed unmixing in SNR=25dB.
[Job satisfaction among Norwegian doctors].
Nylenna, Magne; Aasland, Olaf Gjerløw
2010-05-20
Doctors' job satisfaction has been discussed internationally in recent years based on reports of increasing professional dissatisfaction. We have studied Norwegian doctors' job satisfaction and their general satisfaction with life. A survey was conducted among a representative sample of practicing Norwegian doctors in 2008. The validated 10-item Job Satisfaction Scale was used to assess job satisfaction. 1,072 (65 %) doctors responded. They reported a mean job satisfaction of 5.3 on a scale from 1 (very dissatisfied) to 7 (very satisfied). Job satisfaction increased with increasing age. Private practice specialists reported the highest level of job satisfaction (5.8), and general practitioners reported higher job satisfaction (5.5) than hospital doctors (5.1). Among specialty groups, community doctors scored highest (5.6) and doctors in surgical disciplines lowest (5.0). While long working hours was negatively correlated with job satisfaction, the perception of being professionally updated and having part-time affiliation(s) in addition to a regular job were positively correlated with job satisfaction. 52.9 % of doctors reported a very high general satisfaction. Norwegian doctors have a high level of job satisfaction. Satisfaction with life in general is also high and at least in line with that in the Norwegian population.
Focusing on the Golden Ball Metaheuristic: An Extended Study on a Wider Set of Problems
Directory of Open Access Journals (Sweden)
E. Osaba
2014-01-01
Full Text Available Nowadays, the development of new metaheuristics for solving optimization problems is a topic of interest in the scientific community. In the literature, a large number of techniques of this kind can be found. Anyway, there are many recently proposed techniques, such as the artificial bee colony and imperialist competitive algorithm. This paper is focused on one recently published technique, the one called Golden Ball (GB. The GB is a multiple-population metaheuristic based on soccer concepts. Although it was designed to solve combinatorial optimization problems, until now, it has only been tested with two simple routing problems: the traveling salesman problem and the capacitated vehicle routing problem. In this paper, the GB is applied to four different combinatorial optimization problems. Two of them are routing problems, which are more complex than the previously used ones: the asymmetric traveling salesman problem and the vehicle routing problem with backhauls. Additionally, one constraint satisfaction problem (the n-queen problem and one combinatorial design problem (the one-dimensional bin packing problem have also been used. The outcomes obtained by GB are compared with the ones got by two different genetic algorithms and two distributed genetic algorithms. Additionally, two statistical tests are conducted to compare these results.
Focusing on the Golden Ball Metaheuristic: An Extended Study on a Wider Set of Problems
Osaba, E.; Diaz, F.; Carballedo, R.; Onieva, E.; Perallos, A.
2014-01-01
Nowadays, the development of new metaheuristics for solving optimization problems is a topic of interest in the scientific community. In the literature, a large number of techniques of this kind can be found. Anyway, there are many recently proposed techniques, such as the artificial bee colony and imperialist competitive algorithm. This paper is focused on one recently published technique, the one called Golden Ball (GB). The GB is a multiple-population metaheuristic based on soccer concepts. Although it was designed to solve combinatorial optimization problems, until now, it has only been tested with two simple routing problems: the traveling salesman problem and the capacitated vehicle routing problem. In this paper, the GB is applied to four different combinatorial optimization problems. Two of them are routing problems, which are more complex than the previously used ones: the asymmetric traveling salesman problem and the vehicle routing problem with backhauls. Additionally, one constraint satisfaction problem (the n-queen problem) and one combinatorial design problem (the one-dimensional bin packing problem) have also been used. The outcomes obtained by GB are compared with the ones got by two different genetic algorithms and two distributed genetic algorithms. Additionally, two statistical tests are conducted to compare these results. PMID:25165742
Kellerer, Hans; Pisinger, David
2004-01-01
Thirteen years have passed since the seminal book on knapsack problems by Martello and Toth appeared. On this occasion a former colleague exclaimed back in 1990: "How can you write 250 pages on the knapsack problem?" Indeed, the definition of the knapsack problem is easily understood even by a non-expert who will not suspect the presence of challenging research topics in this area at the first glance. However, in the last decade a large number of research publications contributed new results for the knapsack problem in all areas of interest such as exact algorithms, heuristics and approximation schemes. Moreover, the extension of the knapsack problem to higher dimensions both in the number of constraints and in the num ber of knapsacks, as well as the modification of the problem structure concerning the available item set and the objective function, leads to a number of interesting variations of practical relevance which were the subject of intensive research during the last few years. Hence, two years ago ...
Efficient Searching with Linear Constraints
DEFF Research Database (Denmark)
Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff
2000-01-01
We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint. This pr...
Deepening Contractions and Collateral Constraints
DEFF Research Database (Denmark)
Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano
and occasionally non-binding credit constraints. Easier credit access increases the likelihood that constraints become slack in the face of expansionary shocks, while contractionary shocks are further amplified due to tighter constraints. As a result, busts gradually become deeper than booms. Based...
Constraint Logic Programming approach to protein structure prediction
Directory of Open Access Journals (Sweden)
Fogolari Federico
2004-11-01
Full Text Available Abstract Background The protein structure prediction problem is one of the most challenging problems in biological sciences. Many approaches have been proposed using database information and/or simplified protein models. The protein structure prediction problem can be cast in the form of an optimization problem. Notwithstanding its importance, the problem has very seldom been tackled by Constraint Logic Programming, a declarative programming paradigm suitable for solving combinatorial optimization problems. Results Constraint Logic Programming techniques have been applied to the protein structure prediction problem on the face-centered cube lattice model. Molecular dynamics techniques, endowed with the notion of constraint, have been also exploited. Even using a very simplified model, Constraint Logic Programming on the face-centered cube lattice model allowed us to obtain acceptable results for a few small proteins. As a test implementation their (known secondary structure and the presence of disulfide bridges are used as constraints. Simplified structures obtained in this way have been converted to all atom models with plausible structure. Results have been compared with a similar approach using a well-established technique as molecular dynamics. Conclusions The results obtained on small proteins show that Constraint Logic Programming techniques can be employed for studying protein simplified models, which can be converted into realistic all atom models. The advantage of Constraint Logic Programming over other, much more explored, methodologies, resides in the rapid software prototyping, in the easy way of encoding heuristics, and in exploiting all the advances made in this research area, e.g. in constraint propagation and its use for pruning the huge search space.
Constraint Logic Programming approach to protein structure prediction.
Dal Palù, Alessandro; Dovier, Agostino; Fogolari, Federico
2004-11-30
The protein structure prediction problem is one of the most challenging problems in biological sciences. Many approaches have been proposed using database information and/or simplified protein models. The protein structure prediction problem can be cast in the form of an optimization problem. Notwithstanding its importance, the problem has very seldom been tackled by Constraint Logic Programming, a declarative programming paradigm suitable for solving combinatorial optimization problems. Constraint Logic Programming techniques have been applied to the protein structure prediction problem on the face-centered cube lattice model. Molecular dynamics techniques, endowed with the notion of constraint, have been also exploited. Even using a very simplified model, Constraint Logic Programming on the face-centered cube lattice model allowed us to obtain acceptable results for a few small proteins. As a test implementation their (known) secondary structure and the presence of disulfide bridges are used as constraints. Simplified structures obtained in this way have been converted to all atom models with plausible structure. Results have been compared with a similar approach using a well-established technique as molecular dynamics. The results obtained on small proteins show that Constraint Logic Programming techniques can be employed for studying protein simplified models, which can be converted into realistic all atom models. The advantage of Constraint Logic Programming over other, much more explored, methodologies, resides in the rapid software prototyping, in the easy way of encoding heuristics, and in exploiting all the advances made in this research area, e.g. in constraint propagation and its use for pruning the huge search space.
Customer satisfaction and competencies
DEFF Research Database (Denmark)
Gritti, Paola; Foss, Nicolai Juul
We empirically address how customer satisfaction and loyalty in the banking industry may affect profitability. This helps to identify the strategy and competencies necessary to benefit from customer relationships which are important sources for improved performance in the banking. We do......, loyalty is a mediator between financial and not-financial customer value and two sources of customer satisfaction, namely relationships with the front office and the branch, on the one hand, and the products offered, on the other....... this by analyzing data collected on 2,105 customers of 118 branches of one of the biggest banks of an Italian banking group. We find that customer satisfaction impacts loyalty, which in turn has a direct effect on financial and non-financial customer value/total customer value/complex customer value. Moreover...
Laudet, Alexandre B.; Morgen, Keith; White, William L.
2006-01-01
SUMMARY Many recovering substance users report quitting drugs because they wanted a better life. The road of recovery is the path to a better life but a challenging and stressful path for most. There has been little research among recovering persons in spite of the numbers involved, and most research has focused on substance use outcomes. This study examines stress and quality of life as a function of time in recovery, and uses structural equation modeling to test the hypothesis that social supports, spirituality, religiousness, life meaning, and 12-step affiliation buffer stress toward enhanced life satisfaction. Recovering persons (N = 353) recruited in New York City were mostly inner-city ethnic minority members whose primary substance had been crack or heroin. Longer recovery time was significantly associated with lower stress and with higher quality of life. Findings supported the study hypothesis; the ‘buffer’ constructs accounted for 22% of the variance in life satisfaction. Implications for research and clinical practice are discussed. PMID:16892161
A Production Planning Model for Make-to-Order Foundry Flow Shop with Capacity Constraint
Directory of Open Access Journals (Sweden)
Xixing Li
2017-01-01
Full Text Available The mode of production in the modern manufacturing enterprise mainly prefers to MTO (Make-to-Order; how to reasonably arrange the production plan has become a very common and urgent problem for enterprises’ managers to improve inner production reformation in the competitive market environment. In this paper, a mathematical model of production planning is proposed to maximize the profit with capacity constraint. Four kinds of cost factors (material cost, process cost, delay cost, and facility occupy cost are considered in the proposed model. Different factors not only result in different profit but also result in different satisfaction degrees of customers. Particularly, the delay cost and facility occupy cost cannot reach the minimum at the same time; the two objectives are interactional. This paper presents a mathematical model based on the actual production process of a foundry flow shop. An improved genetic algorithm (IGA is proposed to solve the biobjective problem of the model. Also, the gene encoding and decoding, the definition of fitness function, and genetic operators have been illustrated. In addition, the proposed algorithm is used to solve the production planning problem of a foundry flow shop in a casting enterprise. And comparisons with other recently published algorithms show the efficiency and effectiveness of the proposed algorithm.
Financial satisfaction and financial stressors in marital satisfaction.
Archuleta, Kristy L; Britt, Sonya L; Tonn, Teresa J; Grable, John E
2011-04-01
Using a sample of 310 married respondents from one U.S. Midwestern state, a test was conducted to examine the association of financial satisfaction and financial stressors in a spouse's decision to stay married to the same person or leave the relationship. The role of demographic and socioeconomic variables, religiosity, psychological constructs, financial satisfaction, and financial stressors as factors influencing marital satisfaction was tested. Financial stressors were measured using a list of financial stressors adapted from the literature. Financial satisfaction was measured with a one-item scale. The Kansas Marital Satisfaction Scale was used as a validation tool to assess whether individuals would marry or not marry again. Religiosity and financial satisfaction were positively associated with marital satisfaction. A negative interaction between financial satisfaction and financial stressors was also noted. Findings suggest that respondents who are financially satisfied tend to be more stable in their marriages.
Occupant satisfaction with new low-energy houses
DEFF Research Database (Denmark)
Knudsen, Henrik Nellemose; Jensen, Ole Michael; Kristensen, Lars
2012-01-01
The development and the erection of low-energy buildings have been intensified in recent years. Still, there are only few studies of the energy performance and occupant satisfaction with living in low-energy houses. A questionnaire survey was therefore carried out among occupants of low-energy ho......The development and the erection of low-energy buildings have been intensified in recent years. Still, there are only few studies of the energy performance and occupant satisfaction with living in low-energy houses. A questionnaire survey was therefore carried out among occupants of low......-energy houses. The purpose was to study occupant satisfaction with new low-energy houses concerning i.a. the perceived indoor climate and the technical installations for heating and ventilation. The survey showed an overall satisfaction with the new low-energy houses, but also that there were problems...... occupant satisfaction in existing and future low-energy houses are given....
Spin glasses and nonlinear constraints in portfolio optimization
Energy Technology Data Exchange (ETDEWEB)
Andrecut, M., E-mail: mircea.andrecut@gmail.com
2014-01-17
We discuss the portfolio optimization problem with the obligatory deposits constraint. Recently it has been shown that as a consequence of this nonlinear constraint, the solution consists of an exponentially large number of optimal portfolios, completely different from each other, and extremely sensitive to any changes in the input parameters of the problem, making the concept of rational decision making questionable. Here we reformulate the problem using a quadratic obligatory deposits constraint, and we show that from the physics point of view, finding an optimal portfolio amounts to calculating the mean-field magnetizations of a random Ising model with the constraint of a constant magnetization norm. We show that the model reduces to an eigenproblem, with 2N solutions, where N is the number of assets defining the portfolio. Also, in order to illustrate our results, we present a detailed numerical example of a portfolio of several risky common stocks traded on the Nasdaq Market.
Spin glasses and nonlinear constraints in portfolio optimization
International Nuclear Information System (INIS)
Andrecut, M.
2014-01-01
We discuss the portfolio optimization problem with the obligatory deposits constraint. Recently it has been shown that as a consequence of this nonlinear constraint, the solution consists of an exponentially large number of optimal portfolios, completely different from each other, and extremely sensitive to any changes in the input parameters of the problem, making the concept of rational decision making questionable. Here we reformulate the problem using a quadratic obligatory deposits constraint, and we show that from the physics point of view, finding an optimal portfolio amounts to calculating the mean-field magnetizations of a random Ising model with the constraint of a constant magnetization norm. We show that the model reduces to an eigenproblem, with 2N solutions, where N is the number of assets defining the portfolio. Also, in order to illustrate our results, we present a detailed numerical example of a portfolio of several risky common stocks traded on the Nasdaq Market.
Molinari, D L; Monserud, M A
2008-01-01
The lack of rural nursing studies makes it impossible to know whether rural and urban nurses perceive personal and organizational factors of job satisfaction similarly. Few reports of rural nurse job satisfaction are available. Since the unprecedented shortage of qualified rural nurses requires a greater understanding of what factors are important to retention, studies are needed. An analysis of the literature indicates job satisfaction is studied as both an independent and dependent variable. In this study, the concept is used to examine the intention to remain employed by measuring individual and organizational characteristics; thus, job satisfaction is used as a dependent variable. One hundred and three rural hospital nurses, from hospitals throughout the Northwest region of the United States were recruited for the study. Only nurses employed for more than one year were accepted. The sample completed surveys online. The McCloskey/Mueller Satisfaction Scale, the Gerber Control Over Practice Scale, and two open-ended job satisfaction questions were completed. The qualitative analysis of the open-ended questions identified themes which were then used to support the quantitative findings. Overall alphas were 0.89 for the McCloskey/Mueller Scale and 0.96 for the Gerber Control Over Practice Scale. Rural nurses indicate a preference for rural lifestyles and the incorporation of rural values in organizational practices. Nurses preferred the generalist role with its job variability, and patient variety. Most participants intended to remain employed. The majority of nurses planning to leave employment were unmarried, without children at home, and stated no preference for a rural lifestyle. The least overall satisfied nurses in the sample were employed from 1 to 3 years. Several new findings inform the literature while others support previous workforce studies. Data suggest some job satisfaction elements can be altered by addressing organizational characteristics and by
Ng, Sor-Tho; Hamid, Tengku-Aizan
2013-12-01
To examine the effects of work participation, intergenerational transfers and savings on the life satisfaction of older community-dwelling Malaysians. Data from the 1999 Survey on Perceptions of Needs and Problems of the Elderly on people aged 60 and over were used. The life satisfaction score was constructed from 10 questions adopted from the Life Satisfaction Inventory-A by Neugarten, Havighurst and Tobin. Multiple regression analysis was used to estimate the expected level of life satisfaction. Controlling for other variables in the model, respondents who provided assistance to and received assistance from children with savings had significantly higher life satisfaction than their counterparts, while work participation did not have any significant effect on life satisfaction. Intergenerational transfers and savings are important predictors of life satisfaction. The interdependence between generations should remain and savings habits need to be cultivated to ensure a higher life satisfaction in old age. © 2012 The Authors. Australasian Journal on Ageing © 2012 ACOTA.
Embedded System Synthesis under Memory Constraints
DEFF Research Database (Denmark)
Madsen, Jan; Bjørn-Jørgensen, Peter
1999-01-01
This paper presents a genetic algorithm to solve the system synthesis problem of mapping a time constrained single-rate system specification onto a given heterogeneous architecture which may contain irregular interconnection structures. The synthesis is performed under memory constraints, that is......, the algorithm takes into account the memory size of processors and the size of interface buffers of communication links, and in particular the complicated interplay of these. The presented algorithm is implemented as part of the LY-COS cosynthesis system....
Sexual satisfaction following bariatric surgery: A prospective exploratory study.
Ferrer-Márquez, Manuel; Pomares-Callejón, María Ángeles; Fernández-Agis, Inmaculada; Belda-Lozano, Ricardo; Vidaña-Márquez, Elisabet; Soriano-Maldonado, Alberto
2017-11-01
Bariatric surgery improves sexual function in obese individuals, although the extent to which sexual satisfaction is improved following surgery is unknown. The aims of this study were 1) to describe sexual satisfaction in severely/morbidly obese men and women candidates for bariatric surgery; 2) to assess the effects of bariatric surgery on sexual satisfaction at 12-months follow-up; and 3) to assess whether weight changes at follow-up following bariatric surgery are associated with changes in sexual satisfaction. We conducted a prospective observational study from February 2011 to June 2014. A total of 44 patients with severe/morbid obesity participated in the study. Sexual satisfaction was assessed (at baseline and 12-months follow-up) through the Index of Sexual Satisfaction (ISS) questionnaire. Of 44 patients who completed the ISS at baseline (mean age 40.3 [SD=9.4] years and BMI 46.9 [SD=6.2] kg/m 2 ), 17 were lost to follow-up. The baseline ISS total scores were 32.0 (SD=20.1) in women and 24.4 (SD=16.0) in men (P>0.05). The proportion of sexually satisfied men and women at baseline was 62.5% and 46.4%, respectively (P=0.360). At follow-up, sexual satisfaction improved significantly in women (average difference 13.7 units; P=0.032) but not in men (average difference 3.6 units; P=0.717). The percentage of women with sexual satisfaction problems was reduced by 33% at follow-up (P=0.038). A relatively large percentage of severely/morbidly obese women and men present clinically significant sexual satisfaction problems before undergoing bariatric surgery. Sexual satisfaction improves significantly 12 months following bariatric surgery, particularly in women. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.
Design with Nonlinear Constraints
Tang, Chengcheng
2015-12-10
Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.
Searching for genomic constraints
Energy Technology Data Exchange (ETDEWEB)
Lio` , P [Cambridge, Univ. (United Kingdom). Genetics Dept.; Ruffo, S [Florence, Univ. (Italy). Fac. di Ingegneria. Dipt. di Energetica ` S. Stecco`
1998-01-01
The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call `genomic constraints` from the rules that depend on the `external natural selection` acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour.
Searching for genomic constraints
International Nuclear Information System (INIS)
Lio', P.; Ruffo, S.
1998-01-01
The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call 'genomic constraints' from the rules that depend on the 'external natural selection' acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour
DEFF Research Database (Denmark)
Rostbøll, Christian Fogh
2004-01-01
with harmony in one's entire volitional system, Frankfurt may solve the infi nite regress objection but he does so at the cost of ending up with a description of freedom, which comes very close to being identical to his own description of the wanton. Frankfurt's account leaves open the question of whether......This article is a critical assessment of Harry Frankfurt's hierarchical theory of freedom. It spells out and distinguishes several different and irreconcilable conceptions of freedom present in Frankfurt's work. I argue that Frankfurt is ambiguous in his early formulation as to what conception...... of freedom of the will the hierarchical theory builds on, an avoidability or a satisfaction conception. This ambiguity causes problems in his later attempts to respond to the objections of wantonness of second-order desires and of infi nite regress. With his more recent idea of freedom as being satisfi ed...
Social Interactions in Job Satisfaction
Tumen, Semih; Zeydanli, Tugba
2015-01-01
The literature documents that job satisfaction is positively correlated with worker performance and pro- ductivity. We examine whether aggregate job satisfaction in a certain labor market environment can have an impact on individual-level job satisfaction. If the answer is yes, then policies targeted to increase job satisfaction can increase productivity not only directly, but through spillover externalities too. We seek an answer to this question using two different data sets from the United...
Investigating Teachers' Life Satisfaction
Dagli, Abidin; Baysal, Nigah
2017-01-01
The aim of this study is to determine the life satisfaction perceptions of teachers working at public primary schools according to some variables. In this study, descriptive survey model was used. A random sample of 200 teachers from 25 public primary schools in Diyarbakir/Turkey during 2013-2014 academic year were selected to represent the…
Blai, Boris, Jr.
Psychological theories about human motivation and accommodation to environment can be used to achieve a better understanding of the human factors that function in the work environment. Maslow's theory of human motivational behavior provided a theoretical framework for an empirically-derived method to predict job satisfaction and explore the…
Locke. Edwin A.
Despite considerable interest in the study of job satisfaction and dissatisfaction, our understanding of these phenomena has not increased substantially in the past 30 years. It is argued that a major reason for this lack of progress is the implicit conception of casuality accepted by most psychologists. It is called the policy of "correlation…
Job satisfaction of older workers
Maassen van den Brink, H.; Groot, W.J.N.
1999-01-01
Using data for The Netherlands, this paper analyzes the relation between allocation, wages and job satisfaction. Five conclusions emerge from the empirical analysis: satisfaction with the job content is the main factor explaining overall job satisfaction; the effects of individual and job
Geography of European Life Satisfaction
Okulicz-Kozaryn, Adam
2011-01-01
The vast majority of studies analyze life satisfaction at individual and/or country level. This study contributes with analysis of life satisfaction at the (sub-national) province level across multiple countries. The purpose of this study is to call attention to spatial aspects of life satisfaction. Literature does not discuss the fact that life…
Customer Satisfaction with Public Libraries.
D'Elia, George; Rodger, Eleanor Jo
1996-01-01
Surveys conducted in 142 urban public libraries examined customer satisfaction, comparisons with other libraries, and factors affecting satisfaction. Overall, customers were satisfied with their libraries but experienced different levels of satisfaction based on convenience, availability of materials and information, and services facilitating…
A Simulation Model for Measuring Customer Satisfaction through Employee Satisfaction
Zondiros, Dimitris; Konstantopoulos, Nikolaos; Tomaras, Petros
2007-12-01
Customer satisfaction is defined as a measure of how a firm's product or service performs compared to customer's expectations. It has long been a subject of research due to its importance for measuring marketing and business performance. A lot of models have been developed for its measurement. This paper propose a simulation model using employee satisfaction as one of the most important factors leading to customer satisfaction (the others being expectations and disconfirmation of expectations). Data obtained from a two-year survey in customers of banks in Greece were used. The application of three approaches regarding employee satisfaction resulted in greater customer satisfaction when there is serious effort to keep employees satisfied.
Core Self-Evaluations, life satisfaction, and sport satisfaction
Antón Aluja
2014-01-01
We investigated the association between Core Self-Evaluations (CSE) and life and sport satisfaction to assess whether the Core Self-Evaluations scale was a better predictor of life satisfaction or sport satisfaction. The study included three hundred and thirteen athletes (231 men and 82 women; age range to 47 years (Mage=22.9 years, SDage=5.9 years)). Participants completed the French language version of the CSE scale, the Satisfaction with Life Scale, and the Satisfaction with Sport Scale. A...
Variational constraints for electrical-impedance tomography
International Nuclear Information System (INIS)
Berryman, J.G.; Kohn, R.V.
1990-01-01
The task of electrical-impedance tomography is to invert boundary measurements for the conductivity distribution of a body. This inverse problem can be formulated so the primary data are the measured powers dissipated across injection electrodes. Then, since these powers are minima of the pertinent (dual) variational principles, feasibility constraints can be found for the nonlinear inversion problem. When power may be measured accurately, the existence of these dual variational principles implies that any exact solution must lie at a point of intersection of the two feasibility boundaries
Occupant Experiences and Satisfaction with New Low-Energy Houses
DEFF Research Database (Denmark)
Knudsen, Henrik Nellemose; Thomsen, Kirsten Engelund; Mørck, Ove
2013-01-01
-energy houses that meet the future lower energy requirements of the planned Danish Building Regulations 2015. The purpose was to study experiences and satisfaction among occupants living in new low-energy houses. It included i.a. overall satisfaction, perceived indoor climate and experiences and satisfaction...... be addressed in order to make low-energy houses attractive to ordinary people. Occupants experienced among other things noise from the technical installations and that it was too hot in summer and too cold in winter, that there were a series of problems with the technical installations and that their use...
Patient Satisfaction in Military Dental Treatment Facilities
2006-03-07
the variance in regards to overall satisfaction. 15. SUBJECT TERMS Dentistry, Patient Satisfaction, Military, Consumer Satisfaction, Dental... patient satisfaction in military dental treatment facilities. Dental health is extremely important for the military as dental assets are not always... customer satisfaction is an important component of military dental care. Quarterly patient satisfaction reports are generated for each dental treatment
Near-Optimal Fingerprinting with Constraints
Directory of Open Access Journals (Sweden)
Gulyás Gábor György
2016-10-01
Full Text Available Several recent studies have demonstrated that people show large behavioural uniqueness. This has serious privacy implications as most individuals become increasingly re-identifiable in large datasets or can be tracked, while they are browsing the web, using only a couple of their attributes, called as their fingerprints. Often, the success of these attacks depends on explicit constraints on the number of attributes learnable about individuals, i.e., the size of their fingerprints. These constraints can be budget as well as technical constraints imposed by the data holder. For instance, Apple restricts the number of applications that can be called by another application on iOS in order to mitigate the potential privacy threats of leaking the list of installed applications on a device. In this work, we address the problem of identifying the attributes (e.g., smartphone applications that can serve as a fingerprint of users given constraints on the size of the fingerprint. We give the best fingerprinting algorithms in general, and evaluate their effectiveness on several real-world datasets. Our results show that current privacy guards limiting the number of attributes that can be queried about individuals is insufficient to mitigate their potential privacy risks in many practical cases.
Heat exchanger networks design with constraints
International Nuclear Information System (INIS)
Amidpur, M.; Zoghi, A.; Nasiri, N.
2000-01-01
So far there have been two approaches to the problem of heat recovery system design where stream matching constraints exist. The first approach involves mathematical techniques for solving the combinational problem taking due recognition of the constraints. These methodologies are now efficient, still suffer from the problem of taking a significant amount of control and direction away from the designer. The second approach based upon so called pinch technology and involves the use of adaptation of standard problem table algorithm. Unfortunately, the proposed methodologies are not very easy to understand, therefore they fail to provide the insight and generally associated with these approaches. Here, a new pinch based methodology is presented. In this method, we modified the traditional numerical targeting procedure-problem table algorithm which is stream cascade table. Unconstrained groups are established by using of artificial intelligence method such that they have minimum utility consumption among different alternatives. Each group is an individual network, therefore, traditional optimization, used in pinch technology, should be employed. By transferring energy between groups heat recovery can be maximized, then each group designs individually and finally networks combine together. One of the advantages of using this method is simple targeting and easy networks-design. Besides the approach has the potential using of new network design methods such as dual temperature approach, flexible pinch design, pseudo pinch design. It is hoped that this methodology provides insight easy network design
Supergravity constraints on monojets
International Nuclear Information System (INIS)
Nandi, S.
1986-01-01
In the standard model, supplemented by N = 1 minimal supergravity, all the supersymmetric particle masses can be expressed in terms of a few unknown parameters. The resulting mass relations, and the laboratory and the cosmological bounds on these superpartner masses are used to put constraints on the supersymmetric origin of the CERN monojets. The latest MAC data at PEP excludes the scalar quarks, of masses up to 45 GeV, as the origin of these monojets. The cosmological bounds, for a stable photino, excludes the mass range necessary for the light gluino-heavy squark production interpretation. These difficulties can be avoided by going beyond the minimal supergravity theory. Irrespective of the monojets, the importance of the stable γ as the source of the cosmological dark matter is emphasized
Temporal Concurrent Constraint Programming
DEFF Research Database (Denmark)
Valencia, Frank Dan
Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...... temporal ccp by developing a process calculus called ntcc. The ntcc calculus generalizes the tcc model, the latter being a temporal ccp model for deterministic and synchronouss timed reactive systems. The calculus is built upon few basic ideas but it captures several aspects of timed systems. As tcc, ntcc...... structures, robotic devises, multi-agent systems and music applications. The calculus is provided with a denotational semantics that captures the reactive computations of processes in the presence of arbitrary environments. The denotation is proven to be fully-abstract for a substantial fragment...
Optimal satisfaction degree in energy harvesting cognitive radio networks
International Nuclear Information System (INIS)
Li Zan; Liu Bo-Yang; Si Jiang-Bo; Zhou Fu-Hui
2015-01-01
A cognitive radio (CR) network with energy harvesting (EH) is considered to improve both spectrum efficiency and energy efficiency. A hidden Markov model (HMM) is used to characterize the imperfect spectrum sensing process. In order to maximize the whole satisfaction degree (WSD) of the cognitive radio network, a tradeoff between the average throughput of the secondary user (SU) and the interference to the primary user (PU) is analyzed. We formulate the satisfaction degree optimization problem as a mixed integer nonlinear programming (MINLP) problem. The satisfaction degree optimization problem is solved by using differential evolution (DE) algorithm. The proposed optimization problem allows the network to adaptively achieve the optimal solution based on its required quality of service (Qos). Numerical results are given to verify our analysis. (paper)
Optimal satisfaction degree in energy harvesting cognitive radio networks
Li, Zan; Liu, Bo-Yang; Si, Jiang-Bo; Zhou, Fu-Hui
2015-12-01
A cognitive radio (CR) network with energy harvesting (EH) is considered to improve both spectrum efficiency and energy efficiency. A hidden Markov model (HMM) is used to characterize the imperfect spectrum sensing process. In order to maximize the whole satisfaction degree (WSD) of the cognitive radio network, a tradeoff between the average throughput of the secondary user (SU) and the interference to the primary user (PU) is analyzed. We formulate the satisfaction degree optimization problem as a mixed integer nonlinear programming (MINLP) problem. The satisfaction degree optimization problem is solved by using differential evolution (DE) algorithm. The proposed optimization problem allows the network to adaptively achieve the optimal solution based on its required quality of service (Qos). Numerical results are given to verify our analysis. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education of China (Grant No. 20110203110011), and the 111 Project (Grant No. B08038).
Application of Fuzzy Optimization to the Orienteering Problem
Directory of Open Access Journals (Sweden)
Madhushi Verma
2015-01-01
Full Text Available This paper deals with the orienteering problem (OP which is a combination of two well-known problems (i.e., travelling salesman problem and the knapsack problem. OP is an NP-hard problem and is useful in appropriately modeling several challenging applications. As the parameters involved in these applications cannot be measured precisely, depicting them using crisp numbers is unrealistic. Further, the decision maker may be satisfied with graded satisfaction levels of solutions, which cannot be formulated using a crisp program. To deal with the above-stated two issues, we formulate the fuzzy orienteering problem (FOP and provide a method to solve it. Here we state the two necessary conditions of OP of maximizing the total collected score and minimizing the time taken to traverse a path (within the specified time bound as fuzzy goals and the remaining necessary conditions as crisp constraints. Using the max-min formulation of the fuzzy sets obtained from the fuzzy goals, we calculate the fuzzy decision sets (Z and Z∗ that contain the feasible paths and the desirable paths, respectively, along with the degrees to which they are acceptable. To efficiently solve large instances of FOP, we also present a parallel algorithm on CREW PRAM model.
Asymmetric effects in customer satisfaction
DEFF Research Database (Denmark)
Füller, Johann; Matzler, Kurt; Faullant, Rita
2006-01-01
The results of this study on customer satisfaction in snowboard areas show that the relationship between an attribute and overall satisfaction can indeed be asymmetric. A 30-item self-administered survey was completed by snowboarders (n=2526) in 51 areas in Austria, Germany, Switzerland and Italy....... Results show that waiting time is a dissatisfier; it has a significant impact on overall customer satisfaction in the low satisfaction condition and becomes insignificant in the high satisfaction situation. Restaurants and bars are hybrids, i.e. importance does not depend on performance. Slopes, fun...
Factors Affecting Patient Satisfaction During Endoscopic Procedures
International Nuclear Information System (INIS)
Qureshi, M. O.; Shafqat, F.; Ahmed, S.; Niazi, T. K.; Khokhar, N. K.
2013-01-01
Objective: To assess the quality and patient satisfaction in Endoscopy Unit of Shifa International Hospital. Study Design: Cross-sectional survey. Place and Duration of Study: Division of Gastroenterology, Shifa International Hospital, Islamabad, Pakistan, from July 2011 to January 2012. Methodology: Quality and patient satisfaction after the endoscopic procedure was assessed using a modified GHAA-9 questionnaire. Data was analyzed using SPSS version 16. Results: A total of 1028 patients were included with a mean age of 45 A+- 14.21 years. Out of all the procedures, 670 (65.17%) were gastroscopies, 181 (17.60%) were flexible sigmoidoscopies and 177 (17.21%) were colonoscopies. The maximum unsatisfactory responses were on the waiting time before the procedure (13.13 %), followed by unsatisfactory explanation of the procedure and answers to questions (7.58%). Overall, unsatisfied impression was 4.86%. The problem rate was 6.22%. Conclusion: The quality of procedures and level of satisfaction of patients undergoing a gastroscopy or colonoscopy was generally good. The factors that influence the satisfaction of these patients are related to communication between doctor and patient, doctor's manner and waiting time for the procedure. Feedback information in an endoscopy unit may be useful in improving standards, including the performance of endoscopists. (author)
Clarkin, T. J.; Kasprzyk, J. R.; Raseman, W. J.; Herman, J. D.
2015-12-01
This study contributes a diagnostic assessment of multiobjective evolutionary algorithm (MOEA) search on a set of water resources problem formulations with different configurations of constraints. Unlike constraints in classical optimization modeling, constraints within MOEA simulation-optimization represent limits on acceptable performance that delineate whether solutions within the search problem are feasible. Constraints are relevant because of the emergent pressures on water resources systems: increasing public awareness of their sustainability, coupled with regulatory pressures on water management agencies. In this study, we test several state-of-the-art MOEAs that utilize restricted tournament selection for constraint handling on varying configurations of water resources planning problems. For example, a problem that has no constraints on performance levels will be compared with a problem with several severe constraints, and a problem with constraints that have less severe values on the constraint thresholds. One such problem, Lower Rio Grande Valley (LRGV) portfolio planning, has been solved with a suite of constraints that ensure high reliability, low cost variability, and acceptable performance in a single year severe drought. But to date, it is unclear whether or not the constraints are negatively affecting MOEAs' ability to solve the problem effectively. Two categories of results are explored. The first category uses control maps of algorithm performance to determine if the algorithm's performance is sensitive to user-defined parameters. The second category uses run-time performance metrics to determine the time required for the algorithm to reach sufficient levels of convergence and diversity on the solution sets. Our work exploring the effect of constraints will better enable practitioners to define MOEA problem formulations for real-world systems, especially when stakeholders are concerned with achieving fixed levels of performance according to one or
Lot Sizing Based on Stochastic Demand and Service Level Constraint
Directory of Open Access Journals (Sweden)
hajar shirneshan
2012-06-01
Full Text Available Considering its application, stochastic lot sizing is a significant subject in production planning. Also the concept of service level is more applicable than shortage cost from managers' viewpoint. In this paper, the stochastic multi period multi item capacitated lot sizing problem has been investigated considering service level constraint. First, the single item model has been developed considering service level and with no capacity constraint and then, it has been solved using dynamic programming algorithm and the optimal solution has been derived. Then the model has been generalized to multi item problem with capacity constraint. The stochastic multi period multi item capacitated lot sizing problem is NP-Hard, hence the model could not be solved by exact optimization approaches. Therefore, simulated annealing method has been applied for solving the problem. Finally, in order to evaluate the efficiency of the model, low level criterion has been used .
Minimal Flavor Constraints for Technicolor
DEFF Research Database (Denmark)
Sakuma, Hidenori; Sannino, Francesco
2010-01-01
We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...
Social Constraints on Animate Vision
National Research Council Canada - National Science Library
Breazeal, Cynthia; Edsinger, Aaron; Fitzpatrick, Paul; Scassellati, Brian
2000-01-01
.... In humanoid robotic systems, or in any animate vision system that interacts with people, social dynamics provide additional levels of constraint and provide additional opportunities for processing economy...
Constraint-based job shop scheduling with ILOG SCHEDULER
Nuijten, W.P.M.; Le Pape, C.
1998-01-01
We introduce constraint-based scheduling and discuss its main principles. An approximation algorithm based on tree search is developed for the job shop scheduling problem using ILOG SCHEDULER. A new way of calculating lower bounds on the makespan of the job shop scheduling problem is presented and
Teaching Database Design with Constraint-Based Tutors
Mitrovic, Antonija; Suraweera, Pramuditha
2016-01-01
Design tasks are difficult to teach, due to large, unstructured solution spaces, underspecified problems, non-existent problem solving algorithms and stopping criteria. In this paper, we comment on our approach to develop KERMIT, a constraint-based tutor that taught database design. In later work, we re-implemented KERMIT as EER-Tutor, and…
Distributed Remote Vector Gaussian Source Coding with Covariance Distortion Constraints
DEFF Research Database (Denmark)
Zahedi, Adel; Østergaard, Jan; Jensen, Søren Holdt
2014-01-01
In this paper, we consider a distributed remote source coding problem, where a sequence of observations of source vectors is available at the encoder. The problem is to specify the optimal rate for encoding the observations subject to a covariance matrix distortion constraint and in the presence...
Mars Rover Sample Return aerocapture configuration design and packaging constraints
Lawson, Shelby J.
1989-01-01
This paper discusses the aerodynamics requirements, volume and mass constraints that lead to a biconic aeroshell vehicle design that protects the Mars Rover Sample Return (MRSR) mission elements from launch to Mars landing. The aerodynamic requirements for Mars aerocapture and entry and packaging constraints for the MRSR elements result in a symmetric biconic aeroshell that develops a L/D of 1.0 at 27.0 deg angle of attack. A significant problem in the study is obtaining a cg that provides adequate aerodynamic stability and performance within the mission imposed constraints. Packaging methods that relieve the cg problems include forward placement of aeroshell propellant tanks and incorporating aeroshell structure as lander structure. The MRSR missions developed during the pre-phase A study are discussed with dimensional and mass data included. Further study is needed for some missions to minimize MRSR element volume so that launch mass constraints can be met.
Level-Set Topology Optimization with Aeroelastic Constraints
Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia
2015-01-01
Level-set topology optimization is used to design a wing considering skin buckling under static aeroelastic trim loading, as well as dynamic aeroelastic stability (flutter). The level-set function is defined over the entire 3D volume of a transport aircraft wing box. Therefore, the approach is not limited by any predefined structure and can explore novel configurations. The Sequential Linear Programming (SLP) level-set method is used to solve the constrained optimization problems. The proposed method is demonstrated using three problems with mass, linear buckling and flutter objective and/or constraints. A constraint aggregation method is used to handle multiple buckling constraints in the wing skins. A continuous flutter constraint formulation is used to handle difficulties arising from discontinuities in the design space caused by a switching of the critical flutter mode.
Model quality assessment using distance constraints from alignments
DEFF Research Database (Denmark)
Paluszewski, Martin; Karplus, Kevin
2008-01-01
that model which is closest to the true structure. In this article, we present a new approach for addressing the MQA problem. It is based on distance constraints extracted from alignments to templates of known structure, and is implemented in the Undertaker program for protein structure prediction. One novel...... feature is that we extract noncontact constraints as well as contact constraints. We describe how the distance constraint extraction is done and we show how they can be used to address the MQA problem. We have compared our method on CASP7 targets and the results show that our method is at least comparable...... with the best MQA methods that were assessed at CASP7. We also propose a new evaluation measure, Kendall's tau, that is more interpretable than conventional measures used for evaluating MQA methods (Pearson's r and Spearman's rho). We show clear examples where Kendall's tau agrees much more with our intuition...
Alloy design as an inverse problem of cluster expansion models
DEFF Research Database (Denmark)
Larsen, Peter Mahler; Kalidindi, Arvind R.; Schmidt, Søren
2017-01-01
Central to a lattice model of an alloy system is the description of the energy of a given atomic configuration, which can be conveniently developed through a cluster expansion. Given a specific cluster expansion, the ground state of the lattice model at 0 K can be solved by finding the configurat......Central to a lattice model of an alloy system is the description of the energy of a given atomic configuration, which can be conveniently developed through a cluster expansion. Given a specific cluster expansion, the ground state of the lattice model at 0 K can be solved by finding...... the inverse problem in terms of energetically distinct configurations, using a constraint satisfaction model to identify constructible configurations, and show that a convex hull can be used to identify ground states. To demonstrate the approach, we solve for all ground states for a binary alloy in a 2D...
Modifier constraint in alkali borophosphate glasses using topological constraint theory
Energy Technology Data Exchange (ETDEWEB)
Li, Xiang [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zeng, Huidan, E-mail: hdzeng@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Jiang, Qi [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Donghui [Unifrax Corporation, Niagara Falls, NY 14305 (United States); Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Wang, Zhaofeng; Sun, Luyi [Department of Chemical & Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Chen, Jianding [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)
2016-12-01
In recent years, composition-dependent properties of glasses have been successfully predicted using the topological constraint theory. The constraints of the glass network are derived from two main parts: network formers and network modifiers. The constraints of the network formers can be calculated on the basis of the topological structure of the glass. However, the latter cannot be accurately calculated in this way, because of the existing of ionic bonds. In this paper, the constraints of the modifier ions in phosphate glasses were thoroughly investigated using the topological constraint theory. The results show that the constraints of the modifier ions are gradually increased with the addition of alkali oxides. Furthermore, an improved topological constraint theory for borophosphate glasses is proposed by taking the composition-dependent constraints of the network modifiers into consideration. The proposed theory is subsequently evaluated by analyzing the composition dependence of the glass transition temperature in alkali borophosphate glasses. This method is supposed to be extended to other similar glass systems containing alkali ions.
Orthology and paralogy constraints: satisfiability and consistency.
Lafond, Manuel; El-Mabrouk, Nadia
2014-01-01
A variety of methods based on sequence similarity, reconciliation, synteny or functional characteristics, can be used to infer orthology and paralogy relations between genes of a given gene family G. But is a given set C of orthology/paralogy constraints possible, i.e., can they simultaneously co-exist in an evolutionary history for G? While previous studies have focused on full sets of constraints, here we consider the general case where C does not necessarily involve a constraint for each pair of genes. The problem is subdivided in two parts: (1) Is C satisfiable, i.e. can we find an event-labeled gene tree G inducing C? (2) Is there such a G which is consistent, i.e., such that all displayed triplet phylogenies are included in a species tree? Previous results on the Graph sandwich problem can be used to answer to (1), and we provide polynomial-time algorithms for satisfiability and consistency with a given species tree. We also describe a new polynomial-time algorithm for the case of consistency with an unknown species tree and full knowledge of pairwise orthology/paralogy relationships, as well as a branch-and-bound algorithm in the case when unknown relations are present. We show that our algorithms can be used in combination with ProteinOrtho, a sequence similarity-based orthology detection tool, to extract a set of robust orthology/paralogy relationships.
Seismological Constraints on Geodynamics
Lomnitz, C.
2004-12-01
Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over
Einstein constraints in the Yang-Mills form
International Nuclear Information System (INIS)
Ashtekar, A.
1987-01-01
It is pointed out that constraints of Einstein's theory play a powerful role in both classical and quantum theory because they generate motions in spacetime, rather than in an internal space. New variables are then introduced on the Einstein phase space in terms of which constraints simplify considerably. In particular, the use of these variables enables one to imbed the constraint surface of Einstein's theory into that of Yang-Mills. The imbedding suggests new lines of attack to a number of problems in classical and quantum gravity and provides new concepts and tools to investigate the microscopic structure of space-time geometry
On Lifecycle Constraints of Artifact-Centric Workflows
Kucukoguz, Esra; Su, Jianwen
Data plays a fundamental role in modeling and management of business processes and workflows. Among the recent "data-aware" workflow models, artifact-centric models are particularly interesting. (Business) artifacts are the key data entities that are used in workflows and can reflect both the business logic and the execution states of a running workflow. The notion of artifacts succinctly captures the fluidity aspect of data during workflow executions. However, much of the technical dimension concerning artifacts in workflows is not well understood. In this paper, we study a key concept of an artifact "lifecycle". In particular, we allow declarative specifications/constraints of artifact lifecycle in the spirit of DecSerFlow, and formulate the notion of lifecycle as the set of all possible paths an artifact can navigate through. We investigate two technical problems: (Compliance) does a given workflow (schema) contain only lifecycle allowed by a constraint? And (automated construction) from a given lifecycle specification (constraint), is it possible to construct a "compliant" workflow? The study is based on a new formal variant of artifact-centric workflow model called "ArtiNets" and two classes of lifecycle constraints named "regular" and "counting" constraints. We present a range of technical results concerning compliance and automated construction, including: (1) compliance is decidable when workflow is atomic or constraints are regular, (2) for each constraint, we can always construct a workflow that satisfies the constraint, and (3) sufficient conditions where atomic workflows can be constructed.
Pairwise Constraint-Guided Sparse Learning for Feature Selection.
Liu, Mingxia; Zhang, Daoqiang
2016-01-01
Feature selection aims to identify the most informative features for a compact and accurate data representation. As typical supervised feature selection methods, Lasso and its variants using L1-norm-based regularization terms have received much attention in recent studies, most of which use class labels as supervised information. Besides class labels, there are other types of supervised information, e.g., pairwise constraints that specify whether a pair of data samples belong to the same class (must-link constraint) or different classes (cannot-link constraint). However, most of existing L1-norm-based sparse learning methods do not take advantage of the pairwise constraints that provide us weak and more general supervised information. For addressing that problem, we propose a pairwise constraint-guided sparse (CGS) learning method for feature selection, where the must-link and the cannot-link constraints are used as discriminative regularization terms that directly concentrate on the local discriminative structure of data. Furthermore, we develop two variants of CGS, including: 1) semi-supervised CGS that utilizes labeled data, pairwise constraints, and unlabeled data and 2) ensemble CGS that uses the ensemble of pairwise constraint sets. We conduct a series of experiments on a number of data sets from University of California-Irvine machine learning repository, a gene expression data set, two real-world neuroimaging-based classification tasks, and two large-scale attribute classification tasks. Experimental results demonstrate the efficacy of our proposed methods, compared with several established feature selection methods.
Learning With Mixed Hard/Soft Pointwise Constraints.
Gnecco, Giorgio; Gori, Marco; Melacci, Stefano; Sanguineti, Marcello
2015-09-01
A learning paradigm is proposed and investigated, in which the classical framework of learning from examples is enhanced by the introduction of hard pointwise constraints, i.e., constraints imposed on a finite set of examples that cannot be violated. Such constraints arise, e.g., when requiring coherent decisions of classifiers acting on different views of the same pattern. The classical examples of supervised learning, which can be violated at the cost of some penalization (quantified by the choice of a suitable loss function) play the role of soft pointwise constraints. Constrained variational calculus is exploited to derive a representer theorem that provides a description of the functional structure of the optimal solution to the proposed learning paradigm. It is shown that such an optimal solution can be represented in terms of a set of support constraints, which generalize the concept of support vectors and open the doors to a novel learning paradigm, called support constraint machines. The general theory is applied to derive the representation of the optimal solution to the problem of learning from hard linear pointwise constraints combined with soft pointwise constraints induced by supervised examples. In some cases, closed-form optimal solutions are obtained.
Dermatologists happiness and satisfaction
Fierro-Arias, Leonel; Simón-Díaz, Pilar; Ponce-Olivera, Rosa María; Arenas-Guzmán, Roberto
2018-01-01
To assess the level of happiness and satisfaction in the life and medical practice of dermatologists in Mexico. A descriptive study (online survey) was conducted focused on practicing dermatologists in our country. Questions included demographic characteristics, the Pemberton happiness index (with local validation) and questions that assessed the degree of personal satisfaction. Descriptive statistics were used to obtain the central tendency and dispersion. Measures of central tendency and dispersion were performed; to compare categorical variables, contingency tables for chi-square test were used and when comparing quantitative variables with normal distribution, Student’s t t-test was used. 219 surveys were included, 72.6% female and 27.4% male, with an average age of 45.6 and an average of 16 years of medical practice. Most of them (64.8%) graduate from Mexico City; 93% were very satisfied with the specialty and 98.6% of them would choose the same once again, the most important reason is to encompass medical and surgical areas. The level of happiness by using the Pemberton scale was “high” (mode: 9.11; standard deviation: 1.73). This first study in Latin America on this subject in dermatologists showed high levels of satisfaction and happiness in both professional and personal areas. Copyright: © 2018 SecretarÍa de Salud
Hybrid systems with constraints
Daafouz, Jamal; Sigalotti, Mario
2013-01-01
Control theory is the main subject of this title, in particular analysis and control design for hybrid dynamic systems.The notion of hybrid systems offers a strong theoretical and unified framework to cope with the modeling, analysis and control design of systems where both continuous and discrete dynamics interact. The theory of hybrid systems has been the subject of intensive research over the last decade and a large number of diverse and challenging problems have been investigated. Nevertheless, many important mathematical problems remain open.This book is dedicated mainly to
Oppel, Eva-Maria; Winter, Vera; Schreyögg, Jonas
Patient satisfaction with quality of care is becoming increasingly important in the competitive hospital market. Simultaneously, the growing shortage of clinical staff poses a considerable challenge to ensuring a high quality of care. In this context, a question emerges regarding whether and how human resource management (HRM) might serve as a means to reduce staff shortage problems and to increase patient satisfaction. Although considerable efforts have been devoted to understanding the concepts of patient satisfaction and HRM, little is known about the interrelationships between these concepts or about the link between staff shortage problems and patients' satisfaction with quality of care. The aim of this study was to investigate the relationship between strategic human resource management (SHRM), staff shortage problems, and patients' satisfaction with care. Furthermore, we analyze how the HRM decision to fill short-term vacancies through temporary staffing affects patient satisfaction. We differentiate between physicians and nurses. We develop and empirically test a theoretical model. The data (n = 165) are derived from a survey on SHRM that was sent to 732 German hospitals and from a survey on patient satisfaction that comprises 436,848 patient satisfaction ratings. We use a structural equation modeling approach to test the model. The results indicate that SHRM significantly reduces staff shortage problems for both occupational groups. Having fewer physician shortage problems is significantly associated with higher levels of patient satisfaction, whereas this effect is not significant for nurses. Furthermore, the use of temporary staffing considerably reduces patients' satisfaction with care. Hospital managers are advised to consider the effects of HRM decisions on patients' satisfaction with care. In particular, investments in SHRM targeted at physicians have significantly positive effects on patient satisfaction, whereas the temporary staffing of physicians
Phase-Field Relaxation of Topology Optimization with Local Stress Constraints
DEFF Research Database (Denmark)
Stainko, Roman; Burger, Martin
2006-01-01
inequality constraints. We discretize the problem by finite elements and solve the arising finite-dimensional programming problems by a primal-dual interior point method. Numerical experiments for problems with local stress constraints based on different criteria indicate the success and robustness......We introduce a new relaxation scheme for structural topology optimization problems with local stress constraints based on a phase-field method. In the basic formulation we have a PDE-constrained optimization problem, where the finite element and design analysis are solved simultaneously...
Observational constraints on interstellar chemistry
International Nuclear Information System (INIS)
Winnewisser, G.
1984-01-01
The author points out presently existing observational constraints in the detection of interstellar molecular species and the limits they may cast on our knowledge of interstellar chemistry. The constraints which arise from the molecular side are summarised and some technical difficulties encountered in detecting new species are discussed. Some implications for our understanding of molecular formation processes are considered. (Auth.)
Market segmentation using perceived constraints
Jinhee Jun; Gerard Kyle; Andrew Mowen
2008-01-01
We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...
Fixed Costs and Hours Constraints
Johnson, William R.
2011-01-01
Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…
An Introduction to 'Creativity Constraints'
DEFF Research Database (Denmark)
Onarheim, Balder; Biskjær, Michael Mose
2013-01-01
Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...
Constraint Programming for Context Comprehension
DEFF Research Database (Denmark)
Christiansen, Henning
2014-01-01
A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces...
Canadian nurse practitioner job satisfaction.
LaMarche, Kimberley; Tullai-McGuinness, Susan
2009-01-01
To examine the level of job satisfaction and its association with extrinsic and intrinsic job satisfaction characteristics among Canadian primary healthcare nurse practitioners (NPs). A descriptive correlational design was used to collect data on NPs' job satisfaction and on the factors that influence their job satisfaction. A convenience sample of licensed Canadian NPs was recruited from established provincial associations and special-interest groups. Data about job satisfaction were collected using two valid and reliable instruments, the Misener Nurse Practitioner Job Satisfaction Survey and the Minnesota Satisfaction Questionnaire. Descriptive statistics, Pearson correlation and regression analysis were used to describe the results. The overall job satisfaction for this sample ranged from satisfied to highly satisfied. The elements that had the most influence on overall job satisfaction were the extrinsic category of partnership/collegiality and the intrinsic category of challenge/autonomy. These findings were consistent with Herzberg's Dual Factor Theory of Job Satisfaction. The outcomes of this study will serve as a foundation for designing effective human health resource retention and recruitment strategies that will assist in enhancing the implementation and the successful preservation of the NP's role.
Results on stabilization of nonlinear systems under finite data-rate constraints
Persis, Claudio De
2004-01-01
We discuss in this paper a result concerning the stabilization problem of nonlinear systems under data-rate constraints using output feedback. To put the result in a broader context, we shall first review a number of recent contributions on the stabilization problem under data-rate constraints when
Implementing Run-Time Evaluation of Distributed Timing Constraints in a Real-Time Environment
DEFF Research Database (Denmark)
Kristensen, C. H.; Drejer, N.
1994-01-01
In this paper we describe a solution to the problem of implementing run-time evaluation of timing constraints in distributed real-time environments......In this paper we describe a solution to the problem of implementing run-time evaluation of timing constraints in distributed real-time environments...
Implementering Run-time Evaluation of Distributed Timing Constraints in a Micro Kernel
DEFF Research Database (Denmark)
Kristensen, C.H.; Drejer, N.; Nielsen, Jens Frederik Dalsgaard
In the present paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems......In the present paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems...
Influence of working conditions on job satisfaction in anaesthetists.
Kinzl, J F; Knotzer, H; Traweger, C; Lederer, W; Heidegger, T; Benzer, A
2005-02-01
We studied job satisfaction, physical health, emotional well-being and working conditions in 125 Austrian and Swiss anaesthetists. Responses to self-reporting questionnaires were evaluated. Dependent variables included job satisfaction, emotional well-being and physical health. Independent variables included age, sex, marital status, position and working conditions as assessed by the Instrument for Stress-related Job Analysis. Control over work shows a strong effect on job satisfaction in anaesthetists, for example influence on handling tasks (P=0.001), time control (P=0.002) and participation (P=0.001), whereas task demands and task-related problems did not have any effect. Anaesthetists in leading positions and specialists reported lower job satisfaction (P=0.012) than did anaesthetists in non-leading positions. Job satisfaction was associated with better physical health (P=0.001) and better emotional well-being (P=0.005). Our results suggest that a high level of job satisfaction in anaesthetists correlates with interesting work demands and the opportunity to contribute skills and ideas. To improve job satisfaction, more attention should be paid to improving working conditions, including control over decision-making, and allowing anaesthetists to have more influence on their own work pace and work schedule.
Vocabulary Constraint on Texts
Directory of Open Access Journals (Sweden)
C. Sutarsyah
2008-01-01
Full Text Available This case study was carried out in the English Education Department of State University of Malang. The aim of the study was to identify and describe the vocabulary in the reading text and to seek if the text is useful for reading skill development. A descriptive qualitative design was applied to obtain the data. For this purpose, some available computer programs were used to find the description of vocabulary in the texts. It was found that the 20 texts containing 7,945 words are dominated by low frequency words which account for 16.97% of the words in the texts. The high frequency words occurring in the texts were dominated by function words. In the case of word levels, it was found that the texts have very limited number of words from GSL (General Service List of English Words (West, 1953. The proportion of the first 1,000 words of GSL only accounts for 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words account for 26.44% of the running words in the texts.Â It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also defeat the development of students' reading skills and vocabulary enrichment.
Predictors of employer satisfaction: technical and non-technical skills.
Danielson, Jared A; Wu, Tsui-Feng; Fales-Williams, Amanda J; Kirk, Ryan A; Preast, Vanessa A
2012-01-01
Employers of 2007-2009 graduates from Iowa State University College of Veterinary Medicine were asked to respond to a survey regarding their overall satisfaction with their new employees as well as their new employees' preparation in several technical and non-technical skill areas. Seventy-five responses contained complete data and were used in the analysis. Four technical skill areas (data collection, data interpretation, planning, and taking action) and five non-technical skill areas (interpersonal skills, ability to deal with legal issues, business skills, making referrals, and problem solving) were identified. All of the skill area subscales listed above had appropriate reliability (Cronbach's alpha>0.70) and were positively and significantly correlated with overall employer satisfaction. Results of two simultaneous regression analyses indicated that of the four technical skill areas, taking action is the most salient predictor of employer satisfaction. Of the five non-technical skill areas, interpersonal skills, business skills, making referrals, and problem solving were the most important skills in predicting employer satisfaction. Hierarchical regression analysis revealed that all technical skills explained 25% of the variation in employer satisfaction; non-technical skills explained an additional 42% of the variation in employer satisfaction.
The Comparison of Marital Satisfaction between Fertile and Iinfertile Women
Directory of Open Access Journals (Sweden)
Seyed Abdolmajid Bahrainian
2009-04-01
Full Text Available Objectives: This research studied and compared marital satisfaction level of the women who have infertility problem with those who does not have this problem. Methods: Totally 180 persons participated (90 infertile women and 90 fertile women were participated in this study. Participants were comprised of those referring to 3 Tehran city infertility centers. For data gathering in this research, the constructed questionnaire and Enrich Marital Satisfactions questionnaire have been used. Data analysis has been done with use of two independent t-tests and one way variance analysis has been done. Results: Results showed significant difference in satisfaction level of the fertile and infertile women, while, our research hypotheses were not confirmed in this regard by studying factors effective on marital satisfaction of the infertile women. The number of unsuccessful pregnancies whether in fertile women or infertile women didn’t have considerable effect on the marital satisfaction, while, effect of this factor on marital satisfaction level of the infertile women was higher than that on the fertile women. Discussion: Generally, by inclusion of limitations in this plan, it is impossible to generalize the present research results with difficulty, though it is inevitable to emphasize on negative consequences of the spouses' life and it is important to pay attention to its different dimensions.
Constraint Embedding Technique for Multibody System Dynamics
Woo, Simon S.; Cheng, Michael K.
2011-01-01
Multibody dynamics play a critical role in simulation testbeds for space missions. There has been a considerable interest in the development of efficient computational algorithms for solving the dynamics of multibody systems. Mass matrix factorization and inversion techniques and the O(N) class of forward dynamics algorithms developed using a spatial operator algebra stand out as important breakthrough on this front. Techniques such as these provide the efficient algorithms and methods for the application and implementation of such multibody dynamics models. However, these methods are limited only to tree-topology multibody systems. Closed-chain topology systems require different techniques that are not as efficient or as broad as those for tree-topology systems. The closed-chain forward dynamics approach consists of treating the closed-chain topology as a tree-topology system subject to additional closure constraints. The resulting forward dynamics solution consists of: (a) ignoring the closure constraints and using the O(N) algorithm to solve for the free unconstrained accelerations for the system; (b) using the tree-topology solution to compute a correction force to enforce the closure constraints; and (c) correcting the unconstrained accelerations with correction accelerations resulting from the correction forces. This constraint-embedding technique shows how to use direct embedding to eliminate local closure-loops in the system and effectively convert the system back to a tree-topology system. At this point, standard tree-topology techniques can be brought to bear on the problem. The approach uses a spatial operator algebra approach to formulating the equations of motion. The operators are block-partitioned around the local body subgroups to convert them into aggregate bodies. Mass matrix operator factorization and inversion techniques are applied to the reformulated tree-topology system. Thus in essence, the new technique allows conversion of a system with
ASSESSING CUSTOMER SATISFACTION BASED ON QoS PARAMETERS
Directory of Open Access Journals (Sweden)
Alem Čolaković
2017-03-01
Full Text Available Measurement of customer sastisfaction is an efficient tool to detect problems in SP (Services Provider and their relationship with customers. Based on this measurement a relationship between customer satisfaction and loyalty can be established. It can determine the influence of key parameters on the number of users of services. The parameters of customer satisfaction and loyalty are numerous and depend on the network (network quality of services parameters, the client (the perception, expectations, beliefs, etc., employees (implementation of activities, technological developments, organizational structure, etc. This paper aims to show the way to identify key indicators and their weighted factors that affect customer satisfaction. This paper intends to emphasize relationship between quality of services, customer perception and loyalty and to present a model for examining the key parameters that significantly influence customer satisfaction and how these parameters influence customer loyalty.
Internal marketing and the antecedents of nurse satisfaction and loyalty.
Peltier, James W; Pointer, Lucille; Schibrowsky, John A
2008-01-01
Employee satisfaction and retention are critical issues that influence the success of any organization. Yet, one of the most critical problems facing the worldwide health care industry is the shortage of qualified nurses. Recent calls have been made within the traditional nursing literature for research that utilizes marketing and business models to better understand nurse satisfaction and retention. The purpose of this study is to develop scales that can be used to empirically test a model of the proposed antecedents of nurse job satisfaction and loyalty which have been used widely in the internal marketing and the relationship-marketing literature. Specifically, the study will investigate the degree to which structural bonding, social bonding, financial bonding activities, and quality of care impact how well nurses are satisfied with their job and their commitment to the organization. The results show that quality of care most impacted nurse satisfaction and loyalty, followed by structural, social, and financial bonds.
Measuring satisfaction with public services
Senior, Nicki
2011-01-01
This study used the 'delivery paradox' (Blaug et al. 2006, p.6) as a catalyst to examine customer satisfaction with the public services. The 'delivery paradox' exists where the rise in the level of delivery improvements does not elicit a corresponding rise in public satisfaction with services (ibid). Expectancy Disconfirmation Theory underpins the measurement of customer satisfaction. However, a review of the literature by MORl (2002) concluded that whilst expectations are known to be shaped ...
BRDIČKOVÁ, Monika
2009-01-01
The paper describes life satisfaction in old age. The theoretical part defines negative and positive aspects of old age, and further describes cognitive and emotional changes. The main content of the theoretical part is focused on life satisfaction, purposfulness and self-conception of seniors. The practical part includes qualitative research, which survays life satisfaction of seniors, directed on four dimensions of human life: self-conception, purpose of life, family and social relations. T...
Constraint Optimization Literature Review
2015-11-01
backjumping, learning, and cutset decomposition. Artificial Inteligence . 1989;41:273–312. Approved for public release; distribution is unlimited... artificial intelligence literature (Wallace 1996) and serves as the basis of the COP. It is useful for describing problems in which a set of decisions...Sangal R, Mehta H, Bagga RK, editors. IJCAI’07. Proceedings of the 20th International Joint Conference on Artificial Intelligence; 2007 Jan.; Hyderabad
Diffusion Under Geometrical Constraint
Ogawa, Naohisa
2014-01-01
Here we discus the diffusion of particles in a curved tube. This kind of transport phenomenon is observed in biological cells and porous media. To solve such a problem, we discuss the three dimensional diffusion equation with a confining wall forming a thinner tube. We find that the curvature appears in a effective diffusion coefficient for such a quasi-one-dimensional system. As an application to higher dimensional case, we discuss the diffusion in a curved surface with ...
Retirement Applicant Satisfaction Survey Results
Social Security Administration — This dataset contains information about the Retirement Applicant Survey (RAS). The survey measured satisfaction results with the retirement application process. The...
Patient satisfaction with cataract surgery
Directory of Open Access Journals (Sweden)
Wasfi Ehab I
2008-10-01
Full Text Available Abstract Introduction Measuring the patient satisfaction is a very important issue that will help very much in improving the service provided to patients and improve the level of satisfaction. Aim To evaluate patient satisfaction with the cataract surgery service and identify any areas for improvement, determination of patient satisfaction with referral, out-patient consultation, pre-assessment clinic, surgery and post-operative care, also to report patients' comments relating to improvement in service provision. Methodology A retrospective study was undertaken for 150 patients underwent cataract surgery at Barrow General Hospital, UK, the survey sample was by postal questionnaires. We collected our data from the theatre lists for a period of 4 month. Results This study included 150 patients; the response rate was (72% 108 patients, Most patients were referred from their general practitioner 86.1%, 93 (86.1% patients were happy with the time interval from seeing their GP to eye clinic. In the eye out patient department many factors significantly affected the level of patient satisfaction, in general the more information provided for the patient the more the satisfaction. Conclusion Patient satisfaction is on important health outcome old understanding both the domains of satisfaction as well as their relative importance to patients is necessary to improve the overall quality of patient care. Meeting the doctor, presenting all relevant information and giving printed information are very important factors in improving the patient's satisfaction with cataract surgery.
Healthcare workers satisfaction and patient satisfaction – where is the linkage?
Janicijevic, I; Seke, K; Djokovic, A; Filipovic, T
2013-01-01
Background: This study aims to assess at what level healthcare worker satisfaction affects patient satisfaction, as well as which elements of healthcare worker satisfaction affect health service quality and patient satisfaction.
Validation of satisfaction questionnaire for outpatient neurology ...
African Journals Online (AJOL)
Background: Patient satisfaction questionnaires are the commonly used patient satisfaction measure, and may be global or multidimensional in focus. Global patient satisfaction consists of overall patient satisfaction while multidimensional patient satisfaction has multiple items focusing on different dimensions of the ...
The effect of perceived health status on patient satisfaction.
Xiao, Hong; Barber, Janet P
2008-01-01
To examine the effect of perceived health status on three components of patient satisfaction. The Household Component of the 1999 Medical Expenditure Panel Survey for people 35-64 years of age was used to examine the effect of perceived health status on patient satisfaction measured in terms of access to care, provider quality and quality of care. Descriptive statistics and multivariate regression were used to describe the subjects and to examine the relationship between patient satisfaction and perceived health status controlling for patient demographic factors, health factors and provider characteristics. All analyses used STATA 8.0 which is designed to analyze weighted data. A total of 4,417 patients (71% women) met the inclusion criteria for the study. Patients who rated their health excellent or good scored higher on the three dimensions of patient satisfaction. Higher scores on one or more components of patient satisfaction were associated with being older, married, better educated and having higher income, health insurance and good mental health. Seeing the health-care provider for an old problem resulted in lower levels of patient satisfaction. Provider characteristics significantly related to patient satisfaction were listening to the patient, being a specialist, seeing patients in an office setting and being located in the South. This study has shown that patient satisfaction is influenced by a person's self-perceived health status and other personal characteristics that are external to the delivery of health care. These findings suggest that patient satisfaction data should be used judiciously because a significant portion of the variation may be attributed to factors endogenous to the patient and therefore are not amenable to provider intervention.
Black hole entropy, universality, and horizon constraints
International Nuclear Information System (INIS)
Carlip, Steven
2006-01-01
To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy
Black hole entropy, universality, and horizon constraints
Energy Technology Data Exchange (ETDEWEB)
Carlip, Steven [Department of Physics, University of California, Davis, CA 95616 (United States)
2006-03-01
To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy.
IAEA '77: between politics and factual constraints
International Nuclear Information System (INIS)
Freytag, A.
1976-01-01
The IAEA's organization of its 20th General Conference at Rio de Janeiro clearly underlined the importance of a comprehensive international transfer of nuclear technology. Despite all efforts to keep the Agency out of general political confrontations, the Conference was tinged politically by the PLO and South Africa problems. Besides the next five year program, which was agreed upon in the light of existing factual constraints, the support and control functions of the IAEA and next year's Salzburg Fuel Cycle Conference were other main topics of discussion. The 1977 IAEA budget was approved at a level of 43.5 million, the General Fund at 6.5 million. (orig.) [de