WorldWideScience

Sample records for solution quality heuristics

  1. Combination of graph heuristics in producing initial solution of curriculum based course timetabling problem

    Science.gov (United States)

    Wahid, Juliana; Hussin, Naimah Mohd

    2016-08-01

    The construction of population of initial solution is a crucial task in population-based metaheuristic approach for solving curriculum-based university course timetabling problem because it can affect the convergence speed and also the quality of the final solution. This paper presents an exploration on combination of graph heuristics in construction approach in curriculum based course timetabling problem to produce a population of initial solutions. The graph heuristics were set as single and combination of two heuristics. In addition, several ways of assigning courses into room and timeslot are implemented. All settings of heuristics are then tested on the same curriculum based course timetabling problem instances and are compared with each other in terms of number of population produced. The result shows that combination of saturation degree followed by largest degree heuristic produce the highest number of population of initial solutions. The results from this study can be used in the improvement phase of algorithm that uses population of initial solutions.

  2. Heuristic Solution Approaches to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann

    This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries in ...... are developed for the problem and used with each of the heuristics. Finally some computational results are given along with lower bounds on the objective value....

  3. Heuristic Solution Approaches to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann

    2006-01-01

    This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries in ...... are developed for the problem and used with each of the heuristics. Finally some computational results are given along with lower bounds on the objective value....

  4. Heuristic Model Of The Composite Quality Index Of Environmental Assessment

    Science.gov (United States)

    Khabarov, A. N.; Knyaginin, A. A.; Bondarenko, D. V.; Shepet, I. P.; Korolkova, L. N.

    2017-01-01

    The goal of the paper is to present the heuristic model of the composite environmental quality index based on the integrated application of the elements of utility theory, multidimensional scaling, expert evaluation and decision-making. The composite index is synthesized in linear-quadratic form, it provides higher adequacy of the results of the assessment preferences of experts and decision-makers.

  5. A heuristics-based solution to the continuous berth allocation and crane assignment problem

    Directory of Open Access Journals (Sweden)

    Mohammad Hamdy Elwany

    2013-12-01

    Full Text Available Effective utilization plans for various resources at a container terminal are essential to reducing the turnaround time of cargo vessels. Among the scarcest resources are the berth and its associated cranes. Thus, two important optimization problems arise, which are the berth allocation and quay crane assignment problems. The berth allocation problem deals with the generation of a berth plan, which determines where and when a ship has to berth alongside the quay. The quay crane assignment problem addresses the problem of determining how many and which quay crane(s will serve each vessel. In this paper, an integrated heuristics-based solution methodology is proposed that tackles both problems simultaneously. The preliminary experimental results show that the proposed approach yields high quality solutions to such an NP-hard problem in a reasonable computational time suggesting its suitability for practical use.

  6. Mathematical models and heuristic solutions for container positioning problems in port terminals

    DEFF Research Database (Denmark)

    Kallehauge, Louise Sibbesen

    2008-01-01

    presents an efficient solution algorithm for the CPP. Based on a number of new concepts, an event-based construction heuristic is developed and its ability to solve real-life problem instances is established. The backbone of the algorithm is a list of events, corresponding to a sequence of operations...... by constructing mathematical programming formulations of the problem and developing an efficient heuristic algorithm for its solution. The thesis consists of an introduction, two main chapters concerning new mathematical formulations and a new heuristic for the CPP, technical issues, computational results...... concerning the subject is reviewed. The research presented in this thesis is divided into two main parts: Construction and investigation of new mathematical programming formulations of the CPP and development and implementation of a new event-based heuristic for the problem. The first part presents three...

  7. Exact and heuristic solutions to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Archetti, Claudia; Madsen, Oli B.G.

    -pallet, which can be loaded in 3 stacks in a standard 40 foot container. Different exact and heuristic solution approaches to the DTSPMS have been implemented and tested. The exact approaches are based on different mathematical formulations of the problem which are solved using branch-and-cut. One formulation...... instances. The implemented heuristics include tabu search, simulated annealing and large neighbourhood search. Particularly the LNS approach shows promising results. It finds the known optimal solution of smaller instances (15 orders) within 10 seconds in most cases, and in 3 minutes it finds solutions...

  8. Meta-Heuristics for Dynamic Lot Sizing: a review and comparison of solution approaches

    NARCIS (Netherlands)

    R.F. Jans (Raf); Z. Degraeve (Zeger)

    2004-01-01

    textabstractProofs from complexity theory as well as computational experiments indicate that most lot sizing problems are hard to solve. Because these problems are so difficult, various solution techniques have been proposed to solve them. In the past decade, meta-heuristics such as tabu search,

  9. Is comprehension of problem solutions resistant to misleading heuristic cues?

    Science.gov (United States)

    Ackerman, Rakefet; Leiser, David; Shpigelman, Maya

    2013-05-01

    Previous studies in the domain of metacomprehension judgments have primarily used expository texts. When these texts include illustrations, even uninformative ones, people were found to judge that they understand their content better. The present study aimed to delineate the metacognitive processes involved in understanding problem solutions - a text type often perceived as allowing reliable judgments regarding understanding, and was not previously considered from a metacognitive perspective. Undergraduate students faced difficult problems. They then studied solution explanations with or without uninformative illustrations and provided judgments of comprehension (JCOMPs). Learning was assessed by application to near-transfer problems in an open-book test format. As expected, JCOMPs were polarized - they tended to reflect good or poor understanding. Yet, JCOMPs were higher for the illustrated solutions and even high certainty did not ensure resistance to this effect. Moreover, success in the transfer problems was lower in the presence of illustrations, demonstrating a bias stronger than that found with expository texts. Previous studies have suggested that weak learners are especially prone to being misled by superficial cues. In the present study, matching the difficulty of the task to the ability of the target population revealed that even highly able participants were not immune to misleading cues. The study extends previous findings regarding potential detrimental effects of illustrations and highlights aspects of the metacomprehension process that have not been considered before. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Exact and Heuristic Solutions to Minimize Total Waiting Time in the Blood Products Distribution Problem

    Directory of Open Access Journals (Sweden)

    Amir Salehipour

    2012-01-01

    Full Text Available This paper presents a novel application of operations research to support decision making in blood distribution management. The rapid and dynamic increasing demand, criticality of the product, storage, handling, and distribution requirements, and the different geographical locations of hospitals and medical centers have made blood distribution a complex and important problem. In this study, a real blood distribution problem containing 24 hospitals was tackled by the authors, and an exact approach was presented. The objective of the problem is to distribute blood and its products among hospitals and medical centers such that the total waiting time of those requiring the product is minimized. Following the exact solution, a hybrid heuristic algorithm is proposed. Computational experiments showed the optimal solutions could be obtained for medium size instances, while for larger instances the proposed hybrid heuristic is very competitive.

  11. A Tutorial on Heuristic Methods

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui; Werra, D. de; Silver, E.

    1980-01-01

    In this paper we define a heuristic method as a procedure for solving a well-defined mathematical problem by an intuitive approach in which the structure of the problem can be interpreted and exploited intelligently to obtain a reasonable solution. Issues discussed include: (i) the measurement...... of the quality of a heuristic method, (ii) different types of heuristic procedures, (iii) the interactive role of human beings and (iv) factors that may influence the choice or testing of heuristic methods. A large number of references are included....

  12. A reference-dependent model of the price-quality heuristic

    NARCIS (Netherlands)

    Gneezy, A.; Gneezy, U.; Lauga, D.O.

    2014-01-01

    People often use price as a proxy for quality, resulting in a positive correlation between prices and product liking, known as the "price- quality" (P-Q) heuristic. Using data from three experiments conducted at a winery, this article offers a more complex and complete reference-dependent model of

  13. An Ad-Hoc Initial Solution Heuristic for Metaheuristic Optimization of Energy Market Participation Portfolios

    Directory of Open Access Journals (Sweden)

    Ricardo Faia

    2017-06-01

    Full Text Available The deregulation of the electricity sector has culminated in the introduction of competitive markets. In addition, the emergence of new forms of electric energy production, namely the production of renewable energy, has brought additional changes in electricity market operation. Renewable energy has significant advantages, but at the cost of an intermittent character. The generation variability adds new challenges for negotiating players, as they have to deal with a new level of uncertainty. In order to assist players in their decisions, decision support tools enabling assisting players in their negotiations are crucial. Artificial intelligence techniques play an important role in this decision support, as they can provide valuable results in rather small execution times, namely regarding the problem of optimizing the electricity markets participation portfolio. This paper proposes a heuristic method that provides an initial solution that allows metaheuristic techniques to improve their results through a good initialization of the optimization process. Results show that by using the proposed heuristic, multiple metaheuristic optimization methods are able to improve their solutions in a faster execution time, thus providing a valuable contribution for players support in energy markets negotiations.

  14. Adaptive selection of heuristics for improving exam timetables

    OpenAIRE

    Burke, Edmund; Qu, Rong; Soghier, Amr

    2014-01-01

    This paper presents a hyper-heuristic approach which hybridises low-level heuristic moves to improve timetables. Exams which cause a soft-constraint violation in the timetable are ordered and rescheduled to produce a better timetable. It is observed that both the order in which exams are rescheduled and the heuristic moves used to reschedule the exams and improve the timetable affect the quality of the solution produced. After testing different combinations in a hybrid hyper-heuristic approac...

  15. A New Heuristic Providing an Effective Initial Solution for a Simulated Annealing approach to Energy Resource Scheduling in Smart Grids

    DEFF Research Database (Denmark)

    Sousa, Tiago M; Morais, Hugo; Castro, R.

    2014-01-01

    scheduling problem. Therefore, the use of metaheuristics is required to obtain good solutions in a reasonable amount of time. This paper proposes two new heuristics, called naive electric vehicles charge and discharge allocation and generation tournament based on cost, developed to obtain an initial solution...... to be used in the energy resource scheduling methodology based on simulated annealing previously developed by the authors. The case study considers two scenarios with 1000 and 2000 electric vehicles connected in a distribution network. The proposed heuristics are compared with a deterministic approach...

  16. Comparison of Decisions Quality of Heuristic Methods with Limited Depth-First Search Techniques in the Graph Shortest Path Problem

    Directory of Open Access Journals (Sweden)

    Vatutin Eduard

    2017-12-01

    Full Text Available The article deals with the problem of analysis of effectiveness of the heuristic methods with limited depth-first search techniques of decision obtaining in the test problem of getting the shortest path in graph. The article briefly describes the group of methods based on the limit of branches number of the combinatorial search tree and limit of analyzed subtree depth used to solve the problem. The methodology of comparing experimental data for the estimation of the quality of solutions based on the performing of computational experiments with samples of graphs with pseudo-random structure and selected vertices and arcs number using the BOINC platform is considered. It also shows description of obtained experimental results which allow to identify the areas of the preferable usage of selected subset of heuristic methods depending on the size of the problem and power of constraints. It is shown that the considered pair of methods is ineffective in the selected problem and significantly inferior to the quality of solutions that are provided by ant colony optimization method and its modification with combinatorial returns.

  17. Comparison of Decisions Quality of Heuristic Methods with Limited Depth-First Search Techniques in the Graph Shortest Path Problem

    Science.gov (United States)

    Vatutin, Eduard

    2017-12-01

    The article deals with the problem of analysis of effectiveness of the heuristic methods with limited depth-first search techniques of decision obtaining in the test problem of getting the shortest path in graph. The article briefly describes the group of methods based on the limit of branches number of the combinatorial search tree and limit of analyzed subtree depth used to solve the problem. The methodology of comparing experimental data for the estimation of the quality of solutions based on the performing of computational experiments with samples of graphs with pseudo-random structure and selected vertices and arcs number using the BOINC platform is considered. It also shows description of obtained experimental results which allow to identify the areas of the preferable usage of selected subset of heuristic methods depending on the size of the problem and power of constraints. It is shown that the considered pair of methods is ineffective in the selected problem and significantly inferior to the quality of solutions that are provided by ant colony optimization method and its modification with combinatorial returns.

  18. Learning process mapping heuristics under stochastic sampling overheads

    Science.gov (United States)

    Ieumwananonthachai, Arthur; Wah, Benjamin W.

    1991-01-01

    A statistical method was developed previously for improving process mapping heuristics. The method systematically explores the space of possible heuristics under a specified time constraint. Its goal is to get the best possible heuristics while trading between the solution quality of the process mapping heuristics and their execution time. The statistical selection method is extended to take into consideration the variations in the amount of time used to evaluate heuristics on a problem instance. The improvement in performance is presented using the more realistic assumption along with some methods that alleviate the additional complexity.

  19. Characterizing web heuristics

    NARCIS (Netherlands)

    de Jong, Menno D.T.; van der Geest, Thea

    2000-01-01

    This article is intended to make Web designers more aware of the qualities of heuristics by presenting a framework for analyzing the characteristics of heuristics. The framework is meant to support Web designers in choosing among alternative heuristics. We hope that better knowledge of the

  20. Local search heuristics for the probabilistic dial-a-ride problem

    DEFF Research Database (Denmark)

    Ho, Sin C.; Haugland, Dag

    2011-01-01

    evaluation procedure in a pure local search heuristic and in a tabu search heuristic. The quality of the solutions obtained by the two heuristics have been compared experimentally. Computational results confirm that our neighborhood evaluation technique is much faster than the straightforward one...

  1. MINIMIZING THE PREPARATION TIME OF A TUBES MACHINE: EXACT SOLUTION AND HEURISTICS

    Directory of Open Access Journals (Sweden)

    Robinson S.V. Hoto

    Full Text Available ABSTRACT In this paper we optimize the preparation time of a tubes machine. Tubes are hard tubes made by gluing strips of paper that are packed in paper reels, and some of them may be reused between the production of one and another tube. We present a mathematical model for the minimization of changing reels and movements and also implementations for the heuristics Nearest Neighbor, an improvement of a nearest neighbor (Best Nearest Neighbor, refinements of the Best Nearest Neighbor heuristic and a heuristic of permutation called Best Configuration using the IDE (integrated development environment WxDev C++. The results obtained by simulations improve the one used by the company.

  2. A Bi-Modal Routing Problem with Cyclical and One-Way Trips: Formulation and Heuristic Solution

    Directory of Open Access Journals (Sweden)

    Grinde Roger B.

    2017-12-01

    Full Text Available A bi-modal routing problem is solved using a heuristic approach. Motivated by a recreational hiking application, the problem is similar to routing problems in business with two transport modes. The problem decomposes into a set covering problem (SCP and an asymmetric traveling salesperson problem (ATSP, corresponding to a hiking time objective and a driving distance objective. The solution algorithm considers hiking time first, but finds all alternate optimal solutions, as inputs to the driving distance problem. Results show the trade-offs between the two objectives.

  3. Proposing New Heuristic Approaches for Preventive Maintenance Scheduling

    Directory of Open Access Journals (Sweden)

    majid Esmailian

    2013-08-01

    Full Text Available The purpose of preventive maintenance management is to perform a series of tasks that prevent or minimize production breakdowns and improve reliability of production facilities. An important objective of preventive maintenance management is to minimize downtime of production facilities. In order to accomplish this objective, personnel should efficiently allocate resources and determine an effective maintenance schedule. Gopalakrishnan (1997 developed a mathematical model and four heuristic approaches to solve the preventive maintenance scheduling problem of assigning skilled personnel to work with tasks that require a set of corresponding skills. However, there are several limitations in the prior work in this area of research. The craft combination problem has not been solved because the craft combination is assumed as given. The craft combination problem concerns the computation of all combinations of assigning multi skilled workers to accomplishment of a particular task. In fact, determining craft combinations is difficult because of the exponential number of craft combinations that are possible. This research provides a heuristic approach for determining the craft combination and four new heuristic approach solution for the preventive maintenance scheduling problem with multi skilled workforce constraints. In order to examine the new heuristic approach and to compare the new heuristic approach with heuristic approach of Gopalakrishnan (1997, 81 standard problems have been generated based on the criterion suggested by from Gopalakrishnan (1997. The average solution quality (SQ of the new heuristic approaches is 1.86% and in old heuristic approaches is 8.32%. The solution time of new heuristic approaches are shorter than old heuristic approaches. The solution time of new heuristic approaches is 0.78 second and old heuristic approaches is 6.43 second, but the solution time of mathematical model provided by Gopalakrishnan (1997 is 152 second.

  4. Solution quality improvement in chiller loading optimization

    International Nuclear Information System (INIS)

    Geem, Zong Woo

    2011-01-01

    In order to reduce greenhouse gas emission, we can energy-efficiently operate a multiple chiller system using optimization techniques. So far, various optimization techniques have been proposed to the optimal chiller loading problem. Most of those techniques are meta-heuristic algorithms such as genetic algorithm, simulated annealing, and particle swarm optimization. However, this study applied a gradient-based method, named generalized reduced gradient, and then obtains better results when compared with other approaches. When two additional approaches (hybridization between meta-heuristic algorithm and gradient-based algorithm; and reformulation of optimization structure by adding a binary variable which denotes chiller's operating status) were introduced, generalized reduced gradient found even better solutions. - Highlights: → Chiller loading problem is optimized by generalized reduced gradient (GRG) method. → Results are compared with meta-heuristic algorithms such as genetic algorithm. → Results are even enhanced by hybridizing meta-heuristic and gradient techniques. → Results are even enhanced by modifying the optimization formulation.

  5. Constructing high-quality bounding volume hierarchies for N-body computation using the acceptance volume heuristic

    Science.gov (United States)

    Olsson, O.

    2018-01-01

    We present a novel heuristic derived from a probabilistic cost model for approximate N-body simulations. We show that this new heuristic can be used to guide tree construction towards higher quality trees with improved performance over current N-body codes. This represents an important step beyond the current practice of using spatial partitioning for N-body simulations, and enables adoption of a range of state-of-the-art algorithms developed for computer graphics applications to yield further improvements in N-body simulation performance. We outline directions for further developments and review the most promising such algorithms.

  6. Using heuristic algorithms for capacity leasing and task allocation issues in telecommunication networks under fuzzy quality of service constraints

    Science.gov (United States)

    Huseyin Turan, Hasan; Kasap, Nihat; Savran, Huseyin

    2014-03-01

    Nowadays, every firm uses telecommunication networks in different amounts and ways in order to complete their daily operations. In this article, we investigate an optimisation problem that a firm faces when acquiring network capacity from a market in which there exist several network providers offering different pricing and quality of service (QoS) schemes. The QoS level guaranteed by network providers and the minimum quality level of service, which is needed for accomplishing the operations are denoted as fuzzy numbers in order to handle the non-deterministic nature of the telecommunication network environment. Interestingly, the mathematical formulation of the aforementioned problem leads to the special case of a well-known two-dimensional bin packing problem, which is famous for its computational complexity. We propose two different heuristic solution procedures that have the capability of solving the resulting nonlinear mixed integer programming model with fuzzy constraints. In conclusion, the efficiency of each algorithm is tested in several test instances to demonstrate the applicability of the methodology.

  7. Optimal solution for travelling salesman problem using heuristic shortest path algorithm with imprecise arc length

    Science.gov (United States)

    Bakar, Sumarni Abu; Ibrahim, Milbah

    2017-08-01

    The shortest path problem is a popular problem in graph theory. It is about finding a path with minimum length between a specified pair of vertices. In any network the weight of each edge is usually represented in a form of crisp real number and subsequently the weight is used in the calculation of shortest path problem using deterministic algorithms. However, due to failure, uncertainty is always encountered in practice whereby the weight of edge of the network is uncertain and imprecise. In this paper, a modified algorithm which utilized heuristic shortest path method and fuzzy approach is proposed for solving a network with imprecise arc length. Here, interval number and triangular fuzzy number in representing arc length of the network are considered. The modified algorithm is then applied to a specific example of the Travelling Salesman Problem (TSP). Total shortest distance obtained from this algorithm is then compared with the total distance obtained from traditional nearest neighbour heuristic algorithm. The result shows that the modified algorithm can provide not only on the sequence of visited cities which shown to be similar with traditional approach but it also provides a good measurement of total shortest distance which is lesser as compared to the total shortest distance calculated using traditional approach. Hence, this research could contribute to the enrichment of methods used in solving TSP.

  8. Automatic Generation of Heuristics for Scheduling

    Science.gov (United States)

    Morris, Robert A.; Bresina, John L.; Rodgers, Stuart M.

    1997-01-01

    This paper presents a technique, called GenH, that automatically generates search heuristics for scheduling problems. The impetus for developing this technique is the growing consensus that heuristics encode advice that is, at best, useful in solving most, or typical, problem instances, and, at worst, useful in solving only a narrowly defined set of instances. In either case, heuristic problem solvers, to be broadly applicable, should have a means of automatically adjusting to the idiosyncrasies of each problem instance. GenH generates a search heuristic for a given problem instance by hill-climbing in the space of possible multi-attribute heuristics, where the evaluation of a candidate heuristic is based on the quality of the solution found under its guidance. We present empirical results obtained by applying GenH to the real world problem of telescope observation scheduling. These results demonstrate that GenH is a simple and effective way of improving the performance of an heuristic scheduler.

  9. Numerical solution to generalized Burgers'-Fisher equation using Exp-function method hybridized with heuristic computation.

    Directory of Open Access Journals (Sweden)

    Suheel Abdullah Malik

    Full Text Available In this paper, a new heuristic scheme for the approximate solution of the generalized Burgers'-Fisher equation is proposed. The scheme is based on the hybridization of Exp-function method with nature inspired algorithm. The given nonlinear partial differential equation (NPDE through substitution is converted into a nonlinear ordinary differential equation (NODE. The travelling wave solution is approximated by the Exp-function method with unknown parameters. The unknown parameters are estimated by transforming the NODE into an equivalent global error minimization problem by using a fitness function. The popular genetic algorithm (GA is used to solve the minimization problem, and to achieve the unknown parameters. The proposed scheme is successfully implemented to solve the generalized Burgers'-Fisher equation. The comparison of numerical results with the exact solutions, and the solutions obtained using some traditional methods, including adomian decomposition method (ADM, homotopy perturbation method (HPM, and optimal homotopy asymptotic method (OHAM, show that the suggested scheme is fairly accurate and viable for solving such problems.

  10. Numerical solution to generalized Burgers'-Fisher equation using Exp-function method hybridized with heuristic computation.

    Science.gov (United States)

    Malik, Suheel Abdullah; Qureshi, Ijaz Mansoor; Amir, Muhammad; Malik, Aqdas Naveed; Haq, Ihsanul

    2015-01-01

    In this paper, a new heuristic scheme for the approximate solution of the generalized Burgers'-Fisher equation is proposed. The scheme is based on the hybridization of Exp-function method with nature inspired algorithm. The given nonlinear partial differential equation (NPDE) through substitution is converted into a nonlinear ordinary differential equation (NODE). The travelling wave solution is approximated by the Exp-function method with unknown parameters. The unknown parameters are estimated by transforming the NODE into an equivalent global error minimization problem by using a fitness function. The popular genetic algorithm (GA) is used to solve the minimization problem, and to achieve the unknown parameters. The proposed scheme is successfully implemented to solve the generalized Burgers'-Fisher equation. The comparison of numerical results with the exact solutions, and the solutions obtained using some traditional methods, including adomian decomposition method (ADM), homotopy perturbation method (HPM), and optimal homotopy asymptotic method (OHAM), show that the suggested scheme is fairly accurate and viable for solving such problems.

  11. Adjusted permutation method for multiple attribute decision making with meta-heuristic solution approaches

    Directory of Open Access Journals (Sweden)

    Hossein Karimi

    2011-04-01

    Full Text Available The permutation method of multiple attribute decision making has two significant deficiencies: high computational time and wrong priority output in some problem instances. In this paper, a novel permutation method called adjusted permutation method (APM is proposed to compensate deficiencies of conventional permutation method. We propose Tabu search (TS and particle swarm optimization (PSO to find suitable solutions at a reasonable computational time for large problem instances. The proposed method is examined using some numerical examples to evaluate the performance of the proposed method. The preliminary results show that both approaches provide competent solutions in relatively reasonable amounts of time while TS performs better to solve APM.

  12. The double travelling salesman problem with multiple stacks - Formulation and heuristic solution approaches

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Madsen, Oli B.G.

    2009-01-01

    This paper introduces the double travelling salesman problem with multiple stacks and presents four different metaheuristic approaches to its solution. The double TSP with multiple stacks is concerned with determining the shortest route performing pickups and deliveries in two separated networks...

  13. Scheduling permutation flowshops with initial availability constraint: Analysis of solutions and constructive heuristics

    OpenAIRE

    Pérez González, Paz; Framiñán Torres, José Manuel

    2009-01-01

    In this paper, we address the problem of scheduling a set of jobs in a flowshop with makespan objective. In contrast to the usual assumption of machine availability presented in most research, we consider that machines may not be available at the beginning of the planning period, due to processing of previously scheduled jobs. We first formulate the problem, analyse the structure of solutions depending on a number of factors (such as machines, jobs, structure of the processing times, availabi...

  14. TOUR CONSTRUCTION HEURISTICS FOR AN ORDER SEQUENCING PROBLEM

    Directory of Open Access Journals (Sweden)

    De Villiers, A. P.

    2012-11-01

    Full Text Available An order picking system that requires pickers to move in a clockwise direction around a picking line with fixed locations is considered. The problem is divided into three tiers. The tier in which orders must be sequenced is addressed. Eight tour construction heuristics are developed and implemented for an order picking system operating in unidirectional picking lines. Two classes of tour construction heuristics the tour construction starting position ( and the tour construction ending position ( are developed to sequence orders in a picking line. All algorithms are tested and compared using real life data sets. The best solution quality was obtained by a heuristic with adaptations.

  15. Exact and heuristic solution approaches for the Integrated Job Scheduling and Constrained Network Routing Problem

    DEFF Research Database (Denmark)

    Gamst, M.

    2014-01-01

    problem. The methods are computationally evaluated on test instances arising from telecommunications with up to 500 jobs and 500 machines. Results show that solving the integrated job scheduling and constrained network routing problem to optimality is very difficult. The exact solution approach performs......This paper examines the problem of scheduling a number of jobs on a finite set of machines such that the overall profit of executed jobs is maximized. Each job has a certain demand, which must be sent to the executing machine via constrained paths. A job cannot start before all its demands have...... arrived at the machine. Furthermore, two resource demand transmissions cannot use the same edge in the same time period. The problem has application in grid computing, where a number of geographically distributed machines work together for solving large problems. The machines are connected through...

  16. Solutions to Improve Educational Management Quality

    OpenAIRE

    Ramezan Jahanian; Masoomeh Motahari

    2013-01-01

    Nowadays, enhancing the quality in educational systems of different countries has gained especial importance and stand. Improving utilizing and increasing the quality in our country’s educational system is felt too. One of the utilizing factors in education system is to improve the educational management quality.In this article, effective factors in educational management quality and one of its improving solutions, thorough management quality, is analyzed.

  17. In search of a consumer-focused food classification system. An experimental heuristic approach to differentiate degrees of quality.

    Science.gov (United States)

    Torres-Ruiz, Francisco J; Marano-Marcolini, Carla; Lopez-Zafra, Esther

    2018-06-01

    The present paper focuses on the problems that arise in food classification systems (FCSs), especially when the food product type has different levels or grades of quality. Despite the principal function of these systems being to assist the consumer (to inform, clarify and facilitate choice and purchase), they frequently have the opposite effect. Thus, the main aim of the present research involves providing orientations for the design of effective food classification systems. To address this objective, considering the context of food product consumption (related to heuristic processing), we conducted an experimental study with 720 participants. We analysed the usefulness of heuristic elements by a factorial 2 (category length: short and long) × 3 (visual signs: colours, numbers and images) design in relation to recall and recognition activities. The results showed that the elements used to make the classification more effective for consumers vary depending on whether the user seeks to prioritize the recall or the recognition of product categories. Thus, long categories with images significantly improve recognition, and short categories with colours improve recall. A series of recommendations are provided that can help to enhance FCSs and to make them more intuitive and easier to understand for consumers. Implications with regard to theory and practice are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Heuristics methods for the flow shop scheduling problem with separated setup times

    Directory of Open Access Journals (Sweden)

    Marcelo Seido Nagano

    2012-06-01

    Full Text Available This paper deals with the permutation flow shop scheduling problem with separated machine setup times. As a result of an investigation on the problem characteristics, four heuristics methods are proposed with procedures of the construction sequencing solution by an analogy with the asymmetric traveling salesman problem with the objective of minimizing makespan. Experimental results show that one of the new heuristics methods proposed provide high quality solutions in comparisons with the evaluated methods considered in the literature.

  19. Heuristic methods for shared backup path protection planning

    DEFF Research Database (Denmark)

    Haahr, Jørgen Thorlund; Stidsen, Thomas Riis; Zachariasen, Martin

    2012-01-01

    schemes are employed. In contrast to manual intervention, automatic protection schemes such as Shared Backup Path Protection (SBPP) can recover from failure quickly and efficiently. SBPP is a simple but efficient protection scheme that can be implemented in backbone networks with technology available...... present heuristic algorithms and lower bound methods for the SBPP planning problem. Experimental results show that the heuristic algorithms are able to find good quality solutions in minutes. A solution gap of less than 3.5% was achieved for more than half of the benchmark instances (and a gap of less...

  20. Heuristic methods for single link shared backup path protection

    DEFF Research Database (Denmark)

    Haahr, Jørgen Thorlund; Stidsen, Thomas Riis; Zachariasen, Martin

    2014-01-01

    schemes are employed. In contrast to manual intervention, automatic protection schemes such as shared backup path protection (SBPP) can recover from failure quickly and efficiently. SBPP is a simple but efficient protection scheme that can be implemented in backbone networks with technology available...... heuristic algorithms and lower bound methods for the SBPP planning problem. Experimental results show that the heuristic algorithms are able to find good quality solutions in minutes. A solution gap of less than 3.5 % was achieved for 5 of 7 benchmark instances (and a gap of less than 11 % for the remaining...

  1. A Case Study of Controlling Crossover in a Selection Hyper-heuristic Framework Using the Multidimensional Knapsack Problem.

    Science.gov (United States)

    Drake, John H; Özcan, Ender; Burke, Edmund K

    2016-01-01

    Hyper-heuristics are high-level methodologies for solving complex problems that operate on a search space of heuristics. In a selection hyper-heuristic framework, a heuristic is chosen from an existing set of low-level heuristics and applied to the current solution to produce a new solution at each point in the search. The use of crossover low-level heuristics is possible in an increasing number of general-purpose hyper-heuristic tools such as HyFlex and Hyperion. However, little work has been undertaken to assess how best to utilise it. Since a single-point search hyper-heuristic operates on a single candidate solution, and two candidate solutions are required for crossover, a mechanism is required to control the choice of the other solution. The frameworks we propose maintain a list of potential solutions for use in crossover. We investigate the use of such lists at two conceptual levels. First, crossover is controlled at the hyper-heuristic level where no problem-specific information is required. Second, it is controlled at the problem domain level where problem-specific information is used to produce good-quality solutions to use in crossover. A number of selection hyper-heuristics are compared using these frameworks over three benchmark libraries with varying properties for an NP-hard optimisation problem: the multidimensional 0-1 knapsack problem. It is shown that allowing crossover to be managed at the domain level outperforms managing crossover at the hyper-heuristic level in this problem domain.

  2. Efficient heuristics for maximum common substructure search.

    Science.gov (United States)

    Englert, Péter; Kovács, Péter

    2015-05-26

    Maximum common substructure search is a computationally hard optimization problem with diverse applications in the field of cheminformatics, including similarity search, lead optimization, molecule alignment, and clustering. Most of these applications have strict constraints on running time, so heuristic methods are often preferred. However, the development of an algorithm that is both fast enough and accurate enough for most practical purposes is still a challenge. Moreover, in some applications, the quality of a common substructure depends not only on its size but also on various topological features of the one-to-one atom correspondence it defines. Two state-of-the-art heuristic algorithms for finding maximum common substructures have been implemented at ChemAxon Ltd., and effective heuristics have been developed to improve both their efficiency and the relevance of the atom mappings they provide. The implementations have been thoroughly evaluated and compared with existing solutions (KCOMBU and Indigo). The heuristics have been found to greatly improve the performance and applicability of the algorithms. The purpose of this paper is to introduce the applied methods and present the experimental results.

  3. A flow-first route-next heuristic for liner shipping network design

    DEFF Research Database (Denmark)

    Krogsgaard, Alexander; Pisinger, David; Thorsen, Jesper

    2018-01-01

    Having a well-designed liner shipping network is paramount to ensure competitive freight rates, adequate capacity on trade-lanes, and reasonable transportation times.The most successful algorithms for liner shipping network design make use of a two-phase approach, where they first design the routes...... different operators are used to modify the network. Since each iteration of the local search method involves solving a very complex multi-commodity flow problem to route the containers through the network, the flow problem is solved heuristically by use of a fast Lagrange heuristic. Although the Lagrange...... heuristic for flowing containers is 2–5% from the optimal solution, the solution quality is sufficiently good to guide the variable neighborhood search method in designing the network. Computational results are reported, showing that the developed heuristic is able to find improved solutions for large...

  4. Job shop scheduling with makespan objective: A heuristic approach

    Directory of Open Access Journals (Sweden)

    Mohsen Ziaee

    2014-04-01

    Full Text Available Job shop has been considered as one of the most challenging scheduling problems and there are literally tremendous efforts on reducing the complexity of solution procedure for solving job shop problem. This paper presents a heuristic method to minimize makespan for different jobs in a job shop scheduling. The proposed model is based on a constructive procedure to obtain good quality schedules, very quickly. The performance of the proposed model of this paper is examined on standard benchmarks from the literature in order to evaluate its performance. Computational results show that, despite its simplicity, the proposed heuristic is computationally efficient and practical approach for the problem.

  5. An iterative bidirectional heuristic placement algorithm for solving the two-dimensional knapsack packing problem

    Science.gov (United States)

    Shiangjen, Kanokwatt; Chaijaruwanich, Jeerayut; Srisujjalertwaja, Wijak; Unachak, Prakarn; Somhom, Samerkae

    2018-02-01

    This article presents an efficient heuristic placement algorithm, namely, a bidirectional heuristic placement, for solving the two-dimensional rectangular knapsack packing problem. The heuristic demonstrates ways to maximize space utilization by fitting the appropriate rectangle from both sides of the wall of the current residual space layer by layer. The iterative local search along with a shift strategy is developed and applied to the heuristic to balance the exploitation and exploration tasks in the solution space without the tuning of any parameters. The experimental results on many scales of packing problems show that this approach can produce high-quality solutions for most of the benchmark datasets, especially for large-scale problems, within a reasonable duration of computational time.

  6. Heuristic reasoning

    CERN Document Server

    2015-01-01

    How can we advance knowledge? Which methods do we need in order to make new discoveries? How can we rationally evaluate, reconstruct and offer discoveries as a means of improving the ‘method’ of discovery itself? And how can we use findings about scientific discovery to boost funding policies, thus fostering a deeper impact of scientific discovery itself? The respective chapters in this book provide readers with answers to these questions. They focus on a set of issues that are essential to the development of types of reasoning for advancing knowledge, such as models for both revolutionary findings and paradigm shifts; ways of rationally addressing scientific disagreement, e.g. when a revolutionary discovery sparks considerable disagreement inside the scientific community; frameworks for both discovery and inference methods; and heuristics for economics and the social sciences.

  7. Heuristics for Hierarchical Partitioning with Application to Model Checking

    DEFF Research Database (Denmark)

    Möller, Michael Oliver; Alur, Rajeev

    2001-01-01

    Given a collection of connected components, it is often desired to cluster together parts of strong correspondence, yielding a hierarchical structure. We address the automation of this process and apply heuristics to battle the combinatorial and computational complexity. We define a cost function...... that captures the quality of a structure relative to the connections and favors shallow structures with a low degree of branching. Finding a structure with minimal cost is NP-complete. We present a greedy polynomial-time algorithm that approximates good solutions incrementally by local evaluation of a heuristic...... function. We argue for a heuristic function based on four criteria: the number of enclosed connections, the number of components, the number of touched connections and the depth of the structure. We report on an application in the context of formal verification, where our algorithm serves as a preprocessor...

  8. Sequence-based heuristics for faster annotation of non-coding RNA families.

    Science.gov (United States)

    Weinberg, Zasha; Ruzzo, Walter L

    2006-01-01

    Non-coding RNAs (ncRNAs) are functional RNA molecules that do not code for proteins. Covariance Models (CMs) are a useful statistical tool to find new members of an ncRNA gene family in a large genome database, using both sequence and, importantly, RNA secondary structure information. Unfortunately, CM searches are extremely slow. Previously, we created rigorous filters, which provably sacrifice none of a CM's accuracy, while making searches significantly faster for virtually all ncRNA families. However, these rigorous filters make searches slower than heuristics could be. In this paper we introduce profile HMM-based heuristic filters. We show that their accuracy is usually superior to heuristics based on BLAST. Moreover, we compared our heuristics with those used in tRNAscan-SE, whose heuristics incorporate a significant amount of work specific to tRNAs, where our heuristics are generic to any ncRNA. Performance was roughly comparable, so we expect that our heuristics provide a high-quality solution that--unlike family-specific solutions--can scale to hundreds of ncRNA families. The source code is available under GNU Public License at the supplementary web site.

  9. Efficient heuristics for the Rural Postman Problem

    Directory of Open Access Journals (Sweden)

    GW Groves

    2005-06-01

    Full Text Available A local search framework for the (undirected Rural Postman Problem (RPP is presented in this paper. The framework allows local search approaches that have been applied successfully to the well–known Travelling Salesman Problem also to be applied to the RPP. New heuristics for the RPP, based on this framework, are introduced and these are capable of solving significantly larger instances of the RPP than have been reported in the literature. Test results are presented for a number of benchmark RPP instances in a bid to compare efficiency and solution quality against known methods.

  10. Constraint satisfaction adaptive neural network and heuristics combined approaches for generalized job-shop scheduling.

    Science.gov (United States)

    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.

  11. A heuristic model to quantify the impact of excess cyclodextrin on oral drug absorption from aqueous solution

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2016-01-01

    , the cyclodextrin concentration in the drug product must be higher than the amount needed to solubilise the compound, due to the displacement of the drug from the cyclodextrin cavity by bile salts in the intestinal lumen. On the other hand, dosing cyclodextrin at View the MathML source>DtotSC is expected to result...... the implication of having excess cyclodextrin in an oral solution....

  12. Combined heuristic with fuzzy system to transmission system expansion planning

    Energy Technology Data Exchange (ETDEWEB)

    Silva Sousa, Aldir; Asada, Eduardo N. [University of Sao Paulo, Sao Carlos School of Engineering, Department of Electrical Engineering Av. Trabalhador Sao-carlense, 400, 13566-590 Sao Carlos, SP (Brazil)

    2011-01-15

    A heuristic algorithm that employs fuzzy logic is proposed to the power system transmission expansion planning problem. The algorithm is based on the divide to conquer strategy, which is controlled by the fuzzy system. The algorithm provides high quality solutions with the use of fuzzy decision making, which is based on nondeterministic criteria to guide the search. The fuzzy system provides a self-adjusting mechanism that eliminates the manual adjustment of parameters to each system being solved. (author)

  13. A Solution Approach from an Analytic Model to Heuristic Algorithm for Special Case of Vehicle Routing Problem with Stochastic Demands

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available We define a special case for the vehicle routing problem with stochastic demands (SC-VRPSD where customer demands are normally distributed. We propose a new linear model for computing the expected length of a tour in SC-VRPSD. The proposed model is based on the integration of the “Traveling Salesman Problem” (TSP and the Assignment Problem. For large-scale problems, we also use an Iterated Local Search (ILS algorithm in order to reach an effective solution.

  14. Automated generation of constructive ordering heuristics for educational timetabling

    OpenAIRE

    Pillay, Nelishia; Özcan, Ender

    2017-01-01

    Construction heuristics play an important role in solving combinatorial optimization problems. These heuristics are usually used to create an initial solution to the problem which is improved using optimization techniques such as metaheuristics. For examination timetabling and university course timetabling problems essentially graph colouring heuristics have been used for this purpose. The process of deriving heuristics manually for educational timetabling is a time consuming task. Furthermor...

  15. A lifelong learning hyper-heuristic method for bin packing.

    Science.gov (United States)

    Sim, Kevin; Hart, Emma; Paechter, Ben

    2015-01-01

    We describe a novel hyper-heuristic system that continuously learns over time to solve a combinatorial optimisation problem. The system continuously generates new heuristics and samples problems from its environment; and representative problems and heuristics are incorporated into a self-sustaining network of interacting entities inspired by methods in artificial immune systems. The network is plastic in both its structure and content, leading to the following properties: it exploits existing knowledge captured in the network to rapidly produce solutions; it can adapt to new problems with widely differing characteristics; and it is capable of generalising over the problem space. The system is tested on a large corpus of 3,968 new instances of 1D bin-packing problems as well as on 1,370 existing problems from the literature; it shows excellent performance in terms of the quality of solutions obtained across the datasets and in adapting to dynamically changing sets of problem instances compared to previous approaches. As the network self-adapts to sustain a minimal repertoire of both problems and heuristics that form a representative map of the problem space, the system is further shown to be computationally efficient and therefore scalable.

  16. Comparison of Heuristics for Inhibitory Rule Optimization

    KAUST Repository

    Alsolami, Fawaz; Chikalov, Igor; Moshkov, Mikhail

    2014-01-01

    Friedman test with Nemenyi post-hoc are used to compare the greedy algorithms statistically against each other for length and coverage. The experiments are carried out on real datasets from UCI Machine Learning Repository. For leading heuristics, the constructed rules are compared with optimal ones obtained based on dynamic programming approach. The results seem to be promising for the best heuristics: the average relative difference between length (coverage) of constructed and optimal rules is at most 2.27% (7%, respectively). Furthermore, the quality of classifiers based on sets of inhibitory rules constructed by the considered heuristics are compared against each other, and the results show that the three best heuristics from the point of view classification accuracy coincides with the three well-performed heuristics from the point of view of rule length minimization.

  17. Establishing usability heuristics for heuristics evaluation in a specific domain: Is there a consensus?

    Science.gov (United States)

    Hermawati, Setia; Lawson, Glyn

    2016-09-01

    Heuristics evaluation is frequently employed to evaluate usability. While general heuristics are suitable to evaluate most user interfaces, there is still a need to establish heuristics for specific domains to ensure that their specific usability issues are identified. This paper presents a comprehensive review of 70 studies related to usability heuristics for specific domains. The aim of this paper is to review the processes that were applied to establish heuristics in specific domains and identify gaps in order to provide recommendations for future research and area of improvements. The most urgent issue found is the deficiency of validation effort following heuristics proposition and the lack of robustness and rigour of validation method adopted. Whether domain specific heuristics perform better or worse than general ones is inconclusive due to lack of validation quality and clarity on how to assess the effectiveness of heuristics for specific domains. The lack of validation quality also affects effort in improving existing heuristics for specific domain as their weaknesses are not addressed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Heuristic decision making.

    Science.gov (United States)

    Gigerenzer, Gerd; Gaissmaier, Wolfgang

    2011-01-01

    As reflected in the amount of controversy, few areas in psychology have undergone such dramatic conceptual changes in the past decade as the emerging science of heuristics. Heuristics are efficient cognitive processes, conscious or unconscious, that ignore part of the information. Because using heuristics saves effort, the classical view has been that heuristic decisions imply greater errors than do "rational" decisions as defined by logic or statistical models. However, for many decisions, the assumptions of rational models are not met, and it is an empirical rather than an a priori issue how well cognitive heuristics function in an uncertain world. To answer both the descriptive question ("Which heuristics do people use in which situations?") and the prescriptive question ("When should people rely on a given heuristic rather than a complex strategy to make better judgments?"), formal models are indispensable. We review research that tests formal models of heuristic inference, including in business organizations, health care, and legal institutions. This research indicates that (a) individuals and organizations often rely on simple heuristics in an adaptive way, and (b) ignoring part of the information can lead to more accurate judgments than weighting and adding all information, for instance for low predictability and small samples. The big future challenge is to develop a systematic theory of the building blocks of heuristics as well as the core capacities and environmental structures these exploit.

  19. Quality factor: conceptual problems and practical solutions

    International Nuclear Information System (INIS)

    Dennis, J.A.

    1988-01-01

    In the past ten years a growing divide has become apparent between the dosimetric concepts designed to provide measures of stochastic risks and those designed for the measurement and control of exposures to radiation. Those designed to provide estimates of risk, e.g. effective dose equivalent, might need to be further refined to incorporate the latest scientific beliefs and evidence about the dependence on radiation quality and dose rate as well as on age and sex. Both animal and human evidence strongly supports a belief that different tissues and different types of neoplasm will have different dependencies on radiation quality and dose rate. For practical purposes of risk estimation it is necessary to select the same values for all human neoplasms. There are reasons for using life shortening in animals as a basis for this purpose, but the data for the dependence on the whole range of radiation qualities is meagre. To provide some stability for the new concepts of measurement and calibration it may be better to accommodate changing perceptions on radiation risks by specifying different levels of exposure for different types of radiation without changing the current quality factors for the measurement quantities. (author)

  20. HEURISTICS IN DECISION MAKING

    Directory of Open Access Journals (Sweden)

    I PUTU SUDANA

    2011-01-01

    Full Text Available Prinsip heuristics tidak dapat dikatakan sebagai sebuah pendekatanpengambilan keputusan yang non-rasional, karena penerapan atau penggunaanyang unconscious atau subtle mind tidak dapat dianggap sebagai tindakanyang irrational. Dengan alasan tersebut, terdapat cukup alasan untukmenyatakan bahwa pengklasifikasian pendekatan-pendekatan keputusansemestinya menggunakan terminologi analytical dan experiential, dan bukanmemakai istilah rational dan non-rational seperti yang umumnya diikuti.Penerapan pendekatan heuristics dapat ditemukan pada berbagai disiplin,termasuk bisnis dan akuntansi. Topik heuristics semestinya mendapatperhatian yang cukup luas dari para periset di bidang akuntansi. Bidangbehavioral research in accounting menawarkan banyak kemungkinan untukdikaji, karena prinsip heuristics bertautan erat dengan aspek manusia sebagaipelaku dalam pengambilan keputusan.

  1. Solution Methods for the Periodic Petrol Station Replenishment Problem

    Directory of Open Access Journals (Sweden)

    C Triki

    2013-12-01

    Full Text Available In this paper we introduce the Periodic Petrol Station Replenishment Problem (PPSRP over a T-day planning horizon and describe four heuristic methods for its solution. Even though all the proposed heuristics belong to the common partitioning-then-routing paradigm, they differ in assigning the stations to each day of the horizon. The resulting daily routing problems are then solved exactly until achieving optimalization. Moreover, an improvement procedure is also developed with the aim of ensuring a better quality solution. Our heuristics are tested and compared in two real-life cases, and our computational results show encouraging improvements with respect to a human planning solution

  2. Structural Sustainability - Heuristic Approach

    Science.gov (United States)

    Rostański, Krzysztof

    2017-10-01

    Nowadays, we are faced with a challenge of having to join building structures with elements of nature, which seems to be the paradigm of modern planning and design. The questions arise, however, with reference to the following categories: the leading idea, the relation between elements of nature and buildings, the features of a structure combining such elements and, finally, our perception of this structure. If we consider both the overwhelming globalization and our attempts to preserve local values, the only reasonable solution is to develop naturalistic greenery. It can add its uniqueness to any building and to any developed area. Our holistic model, presented in this paper, contains the above mentioned categories within the scope of naturalism. The model is divided into principles, actions related, and possible effects to be obtained. It provides a useful tool for determining the ways and priorities of our design. Although it is not possible to consider all possible actions and solutions in order to support sustainability in any particular design, we can choose, however, a proper mode for our design according to the local conditions by turning to the heuristic method, which helps to choose priorities and targets. Our approach is an attempt to follow the ways of nature as in the natural environment it is optimal solutions that appear and survive, idealism being the domain of mankind only. We try to describe various natural processes in a manner comprehensible to us, which is always a generalization. Such definitions, however, called artificial by naturalists, are presented as art or the current state of knowledge by artists and engineers. Reality, in fact, is always more complicated than its definitions. The heuristic method demonstrates the way how to optimize our design. It requires that all possible information about the local environment should be gathered, as the more is known, the fewer mistakes are made. Following the unquestionable principles, we can

  3. Comparison of Heuristics for Inhibitory Rule Optimization

    KAUST Repository

    Alsolami, Fawaz

    2014-09-13

    Knowledge representation and extraction are very important tasks in data mining. In this work, we proposed a variety of rule-based greedy algorithms that able to obtain knowledge contained in a given dataset as a series of inhibitory rules containing an expression “attribute ≠ value” on the right-hand side. The main goal of this paper is to determine based on rule characteristics, rule length and coverage, whether the proposed rule heuristics are statistically significantly different or not; if so, we aim to identify the best performing rule heuristics for minimization of rule length and maximization of rule coverage. Friedman test with Nemenyi post-hoc are used to compare the greedy algorithms statistically against each other for length and coverage. The experiments are carried out on real datasets from UCI Machine Learning Repository. For leading heuristics, the constructed rules are compared with optimal ones obtained based on dynamic programming approach. The results seem to be promising for the best heuristics: the average relative difference between length (coverage) of constructed and optimal rules is at most 2.27% (7%, respectively). Furthermore, the quality of classifiers based on sets of inhibitory rules constructed by the considered heuristics are compared against each other, and the results show that the three best heuristics from the point of view classification accuracy coincides with the three well-performed heuristics from the point of view of rule length minimization.

  4. ARCHITECTURE SOFTWARE SOLUTION TO SUPPORT AND DOCUMENT MANAGEMENT QUALITY SYSTEM

    Directory of Open Access Journals (Sweden)

    Milan Eric

    2010-12-01

    Full Text Available One of the basis of a series of standards JUS ISO 9000 is quality system documentation. An architecture of the quality system documentation depends on the complexity of business system. An establishment of an efficient management documentation of system of quality is of a great importance for the business system, as well as in the phase of introducing the quality system and in further stages of its improvement. The study describes the architecture and capability of software solutions to support and manage the quality system documentation in accordance with the requirements of standards ISO 9001:2001, ISO 14001:2005 HACCP etc.

  5. A grouping hyper-heuristic framework: application on graph colouring

    OpenAIRE

    Elhag, Anas; Özcan, Ender

    2015-01-01

    Grouping problems are hard to solve combinatorial optimisation problems which require partitioning of objects into a minimum number of subsets while a given objective is simultaneously optimised. Selection hyper-heuristics are high level general purpose search methodologies that operate on a space formed by a set of low level heuristics rather than solutions. Most of the recently proposed selection hyper-heuristics are iterative and make use of two key methods which are employed successively;...

  6. Heuristic extension of the Schwarzschild metric

    International Nuclear Information System (INIS)

    Espinosa, J.M.

    1982-01-01

    The Schwarzschild solution of Einstein's equations of gravitation has several singularities. It is known that the singularity at r = 2Gm/c 2 is only apparent, a result of the coordinates in which the solution was found. Paradoxical results occuring near the singularity show the system of coordinates is incomplete. We introduce a simple, two-dimensional metric with an apparent singularity that makes it incomplete. By a straightforward, heuristic procedure we extend and complete this simple metric. We then use the same procedure to give a heuristic derivation of the Kruskal system of coordinates, which is known to extend the Schwarzschild manifold past its apparent singularity and produce a complete manifold

  7. Pitfalls in Teaching Judgment Heuristics

    Science.gov (United States)

    Shepperd, James A.; Koch, Erika J.

    2005-01-01

    Demonstrations of judgment heuristics typically focus on how heuristics can lead to poor judgments. However, exclusive focus on the negative consequences of heuristics can prove problematic. We illustrate the problem with the representativeness heuristic and present a study (N = 45) that examined how examples influence understanding of the…

  8. An integral heuristic

    International Nuclear Information System (INIS)

    Kauffman, L.H.

    1990-01-01

    This paper gives a heuristic derivation of the skein relation for the Homfly polynomial in an integral formalism. The derivation is formally correct but highly simplified. In the light of Witten's proposal for invariants of links via functional integrals, it is useful to have a formal pattern to compare with the complexities of the full approach. The formalism is a heuristic. However, it is closely related to the actual structure of the Witten functional integral

  9. Near-Optimal Heuristics for Just-In-Time Jobs Maximization in Flow Shop Scheduling

    Directory of Open Access Journals (Sweden)

    Helio Yochihiro Fuchigami

    2018-04-01

    Full Text Available The number of just-in-time jobs maximization in a permutation flow shop scheduling problem is considered. A mixed integer linear programming model to represent the problem as well as solution approaches based on enumeration and constructive heuristics were proposed and computationally implemented. Instances with up to 10 jobs and five machines are solved by the mathematical model in an acceptable running time (3.3 min on average while the enumeration method consumes, on average, 1.5 s. The 10 constructive heuristics proposed show they are practical especially for large-scale instances (up to 100 jobs and 20 machines, with very good-quality results and efficient running times. The best two heuristics obtain near-optimal solutions, with only 0.6% and 0.8% average relative deviations. They prove to be better than adaptations of the NEH heuristic (well-known for providing very good solutions for makespan minimization in flow shop for the considered problem.

  10. Proximity search heuristics for wind farm optimal layout

    DEFF Research Database (Denmark)

    Fischetti, Martina; Monaci, Michele

    2016-01-01

    A heuristic framework for turbine layout optimization in a wind farm is proposed that combines ad-hoc heuristics and mixed-integer linear programming. In our framework, large-scale mixed-integer programming models are used to iteratively refine the current best solution according to the recently...

  11. Heuristic Classification. Technical Report Number 12.

    Science.gov (United States)

    Clancey, William J.

    A broad range of well-structured problems--embracing forms of diagnosis, catalog selection, and skeletal planning--are solved in expert computer systems by the method of heuristic classification. These programs have a characteristic inference structure that systematically relates data to a pre-enumerated set of solutions by abstraction, heuristic…

  12. Intelligent System Design Using Hyper-Heuristics

    Directory of Open Access Journals (Sweden)

    Nelishia Pillay

    2015-07-01

    Full Text Available Determining the most appropriate search method or artificial intelligence technique to solve a problem is not always evident and usually requires implementation of the different approaches to ascertain this. In some instances a single approach may not be sufficient and hybridization of methods may be needed to find a solution. This process can be time consuming. The paper proposes the use of hyper-heuristics as a means of identifying which method or combination of approaches is needed to solve a problem. The research presented forms part of a larger initiative aimed at using hyper-heuristics to develop intelligent hybrid systems. As an initial step in this direction, this paper investigates this for classical artificial intelligence uninformed and informed search methods, namely depth first search, breadth first search, best first search, hill-climbing and the A* algorithm. The hyper-heuristic determines the search or combination of searches to use to solve the problem. An evolutionary algorithm hyper-heuristic is implemented for this purpose and its performance is evaluated in solving the 8-Puzzle, Towers of Hanoi and Blocks World problems. The hyper-heuristic employs a generational evolutionary algorithm which iteratively refines an initial population using tournament selection to select parents, which the mutation and crossover operators are applied to for regeneration. The hyper-heuristic was able to identify a search or combination of searches to produce solutions for the twenty 8-Puzzle, five Towers of Hanoi and five Blocks World problems. Furthermore, admissible solutions were produced for all problem instances.

  13. A heuristic model for planning problem solution of reactive in electric power systems; Um modelo heuristico para solucao do problema de planejamento de reativos em sistemas de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Jose Roberto Sanches

    1995-02-01

    This work introduces a model to solve the planning problem of reactive in electric power systems. The proposed method uses mixed integer linear programming and is solved using implicit enumeration (binary search). The special heuristics to reduce candidates' initial set and to obtain discreet solutions are adopted. They were going accomplished two algorithm implementations, one sequential and other parallel. The implementation parallel uses an asynchronous programming model and is adjusted for distributed memory computer. Defined a bars candidates set for the new reactive sources allocation, the developed program supplies the location and the reactive sources magnitude that must be allocated in the system, considering safety and operation restrictions. The implementation parallel performance is evaluated for three real systems of 309, 725 and 810 bars. The results for the test systems IEEE30 and IEEE118, and the three real systems used in the implementation parallel evaluation are also presented.

  14. A heuristic model for planning problem solution of reactive in electric power systems; Um modelo heuristico para solucao do problema de planejamento de reativos em sistemas de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Jose Roberto Sanches

    1995-02-01

    This work introduces a model to solve the planning problem of reactive in electric power systems. The proposed method uses mixed integer linear programming and is solved using implicit enumeration (binary search). The special heuristics to reduce candidates' initial set and to obtain discreet solutions are adopted. They were going accomplished two algorithm implementations, one sequential and other parallel. The implementation parallel uses an asynchronous programming model and is adjusted for distributed memory computer. Defined a bars candidates set for the new reactive sources allocation, the developed program supplies the location and the reactive sources magnitude that must be allocated in the system, considering safety and operation restrictions. The implementation parallel performance is evaluated for three real systems of 309, 725 and 810 bars. The results for the test systems IEEE30 and IEEE118, and the three real systems used in the implementation parallel evaluation are also presented.

  15. Heuristics for container loading of furniture

    DEFF Research Database (Denmark)

    Egeblad, Jens; Garavelli, Claudio; Lisi, Stefano

    2010-01-01

    . In the studied company, the problem arises hundreds of times daily during transport planning. Instances may contain more than one hundred different items with irregular shapes. To solve this complex problem we apply a set of heuristics successively that each solve one part of the problem. Large items...... are combined in specific structures to ensure proper protection of the items during transportation and to simplify the problem. The solutions generated by the heuristic has an average loading utilization of 91.3% for the most general instances with average running times around 100 seconds....

  16. Wind energy systems solutions for power quality and stabilization

    CERN Document Server

    Ali, Mohd Hasan

    2012-01-01

    Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases--and wind energy is a free, renewable resource. However, the induction machines commonly used as wind generators have stability problems similar to the transient stability of synchronous machines. To minimize power, frequency, and voltage fluctuations caused by network faults or random wind speed variations, control mechanisms are necessary. Wind Energy Systems: Solutions for Power Quality and Stabilization clearly explains how to solve stability and power quality issues of wind generator systems. Covering

  17. Heuristics for no-wait flow shop scheduling problem

    Directory of Open Access Journals (Sweden)

    Kewal Krishan Nailwal

    2016-09-01

    Full Text Available No-wait flow shop scheduling refers to continuous flow of jobs through different machines. The job once started should have the continuous processing through the machines without wait. This situation occurs when there is a lack of an intermediate storage between the processing of jobs on two consecutive machines. The problem of no-wait with the objective of minimizing makespan in flow shop scheduling is NP-hard; therefore the heuristic algorithms are the key to solve the problem with optimal solution or to approach nearer to optimal solution in simple manner. The paper describes two heuristics, one constructive and an improvement heuristic algorithm obtained by modifying the constructive one for sequencing n-jobs through m-machines in a flow shop under no-wait constraint with the objective of minimizing makespan. The efficiency of the proposed heuristic algorithms is tested on 120 Taillard’s benchmark problems found in the literature against the NEH under no-wait and the MNEH heuristic for no-wait flow shop problem. The improvement heuristic outperforms all heuristics on the Taillard’s instances by improving the results of NEH by 27.85%, MNEH by 22.56% and that of the proposed constructive heuristic algorithm by 24.68%. To explain the computational process of the proposed algorithm, numerical illustrations are also given in the paper. Statistical tests of significance are done in order to draw the conclusions.

  18. The Effects of Silk Protein Solution on Quality of Mangosteen

    International Nuclear Information System (INIS)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree; Kerdchoechuen, Orapin

    2011-06-01

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25 C for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10 C with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks

  19. The Effects of Silk Protein Solution on Quality of Mangosteen

    Energy Technology Data Exchange (ETDEWEB)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree [Thailand Institute of Nuclear Technology, Nakhon Nayok, (Thailand); Kerdchoechuen, Orapin [School of Bioresources and Technology, King Mongkuts University, Bangkok (Thailand)

    2011-06-15

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25{sup C} for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10{sup C} with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks.

  20. A variable neighborhood descent based heuristic to solve the capacitated location-routing problem

    Directory of Open Access Journals (Sweden)

    M. S. Jabal-Ameli

    2011-01-01

    Full Text Available Location-routing problem (LRP is established as a new research area in the context of location analysis. The primary concern of LRP is on locating facilities and routing of vehicles among established facilities and existing demand points. In this work, we address the capacitated LRP which arises in many practical applications within logistics and supply chain management. The objective is to minimize the overall system costs which include the fixed costs of opening depots and using vehicles at each depot site, and the variable costs associated with delivery activities. A novel heuristic is proposed which is based on variable neighborhood descent (VND algorithm to solve the resulted problem. The computational study indicates that the proposed VND based heuristic is highly competitive with the existing solution algorithms in terms of solution quality.

  1. Heuristics: foundations for a novel approach to medical decision making.

    Science.gov (United States)

    Bodemer, Nicolai; Hanoch, Yaniv; Katsikopoulos, Konstantinos V

    2015-03-01

    Medical decision-making is a complex process that often takes place during uncertainty, that is, when knowledge, time, and resources are limited. How can we ensure good decisions? We present research on heuristics-simple rules of thumb-and discuss how medical decision-making can benefit from these tools. We challenge the common view that heuristics are only second-best solutions by showing that they can be more accurate, faster, and easier to apply in comparison to more complex strategies. Using the example of fast-and-frugal decision trees, we illustrate how heuristics can be studied and implemented in the medical context. Finally, we suggest how a heuristic-friendly culture supports the study and application of heuristics as complementary strategies to existing decision rules.

  2. Heuristic for Task-Worker Assignment with Varying Learning Slopes

    Directory of Open Access Journals (Sweden)

    Wipawee Tharmmaphornphilas

    2010-04-01

    Full Text Available Fashion industry has variety products, so the multi-skilled workers are required to improve flexibility in production and assignment. Generally the supervisor will assign task to the workers based on skill and skill levels of worker. Since in fashion industry new product styles are launched more frequently and the order size tends to be smaller, the workers always learn when the raw material and the production process changes. Consequently they require less time to produce the succeeding units of a task based on their learning ability. Since the workers have both experience and inexperience workers, so each worker has different skill level and learning ability. Consequently, the assignment which assumed constant skill level is not proper to use. This paper proposes a task-worker assignment considering worker skill levels and learning abilities. Processing time of each worker changes along production period due to a worker learning ability. We focus on a task-worker assignment in a fashion industry where tasks are ordered in series; the number of tasks is greater than the number of workers. Therefore, workers can perform multiple assignments followed the precedence restriction as an assembly line balancing problem. The problem is formulated in an integer linear programming model with objective to minimize makespan. A heuristic is proposed to determine the lower bound (LB and the upper bound (UB of the problem and the best assignment is determined. The performance of the heuristic method is tested by comparing quality of solution and computational time to optimal solutions.

  3. Heuristic decision making in medicine

    Science.gov (United States)

    Marewski, Julian N.; Gigerenzer, Gerd

    2012-01-01

    Can less information be more helpful when it comes to making medical decisions? Contrary to the common intuition that more information is always better, the use of heuristics can help both physicians and patients to make sound decisions. Heuristics are simple decision strategies that ignore part of the available information, basing decisions on only a few relevant predictors. We discuss: (i) how doctors and patients use heuristics; and (ii) when heuristics outperform information-greedy methods, such as regressions in medical diagnosis. Furthermore, we outline those features of heuristics that make them useful in health care settings. These features include their surprising accuracy, transparency, and wide accessibility, as well as the low costs and little time required to employ them. We close by explaining one of the statistical reasons why heuristics are accurate, and by pointing to psychiatry as one area for future research on heuristics in health care. PMID:22577307

  4. Heuristic decision making in medicine.

    Science.gov (United States)

    Marewski, Julian N; Gigerenzer, Gerd

    2012-03-01

    Can less information be more helpful when it comes to making medical decisions? Contrary to the common intuition that more information is always better, the use of heuristics can help both physicians and patients to make sound decisions. Heuristics are simple decision strategies that ignore part of the available information, basing decisions on only a few relevant predictors. We discuss: (i) how doctors and patients use heuristics; and (ii) when heuristics outperform information-greedy methods, such as regressions in medical diagnosis. Furthermore, we outline those features of heuristics that make them useful in health care settings. These features include their surprising accuracy, transparency, and wide accessibility, as well as the low costs and little time required to employ them. We close by explaining one of the statistical reasons why heuristics are accurate, and by pointing to psychiatry as one area for future research on heuristics in health care.

  5. Heuristic Evaluation for Novice Programming Systems

    OpenAIRE

    Kölling, Michael; McKay, Fraser

    2016-01-01

    The past few years has seen a proliferation of novice programming tools. The availability of a large number of systems has made it difficult for many users to choose among them. Even for education researchers, comparing the relative quality of these tools, or judging their respective suitability for a given context, is hard in many instances. For designers of such systems, assessing the respective quality of competing design decisions can be equally difficult.\\ud Heuristic evaluation provides...

  6. Heuristics in Conflict Resolution

    OpenAIRE

    Drescher, Christian; Gebser, Martin; Kaufmann, Benjamin; Schaub, Torsten

    2010-01-01

    Modern solvers for Boolean Satisfiability (SAT) and Answer Set Programming (ASP) are based on sophisticated Boolean constraint solving techniques. In both areas, conflict-driven learning and related techniques constitute key features whose application is enabled by conflict analysis. Although various conflict analysis schemes have been proposed, implemented, and studied both theoretically and practically in the SAT area, the heuristic aspects involved in conflict analysis have not yet receive...

  7. New insights into diversification of hyper-heuristics.

    Science.gov (United States)

    Ren, Zhilei; Jiang, He; Xuan, Jifeng; Hu, Yan; Luo, Zhongxuan

    2014-10-01

    There has been a growing research trend of applying hyper-heuristics for problem solving, due to their ability of balancing the intensification and the diversification with low level heuristics. Traditionally, the diversification mechanism is mostly realized by perturbing the incumbent solutions to escape from local optima. In this paper, we report our attempt toward providing a new diversification mechanism, which is based on the concept of instance perturbation. In contrast to existing approaches, the proposed mechanism achieves the diversification by perturbing the instance under solving, rather than the solutions. To tackle the challenge of incorporating instance perturbation into hyper-heuristics, we also design a new hyper-heuristic framework HIP-HOP (recursive acronym of HIP-HOP is an instance perturbation-based hyper-heuristic optimization procedure), which employs a grammar guided high level strategy to manipulate the low level heuristics. With the expressive power of the grammar, the constraints, such as the feasibility of the output solution could be easily satisfied. Numerical results and statistical tests over both the Ising spin glass problem and the p -median problem instances show that HIP-HOP is able to achieve promising performances. Furthermore, runtime distribution analysis reveals that, although being relatively slow at the beginning, HIP-HOP is able to achieve competitive solutions once given sufficient time.

  8. Heuristic program to design Relational Databases

    Directory of Open Access Journals (Sweden)

    Manuel Pereira Rosa

    2009-09-01

    Full Text Available The great development of today’s world determines that the world level of information increases day after day, however, the time allowed to transmit this information in the classrooms has not changed. Thus, the rational work in this respect is more than necessary. Besides, if for the solution of a given type of problem we do not have a working algorism, we have, first to look for a correct solution, then the heuristic programs are of paramount importance to succeed in these aspects. Having into consideration that the design of the database is, essentially, a process of problem resolution, this article aims at proposing a heuristic program for the design of the relating database.

  9. Custom power - the utility solution to distribution power quality

    Energy Technology Data Exchange (ETDEWEB)

    Woodley, N H [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1997-04-01

    The design of custom power products for electric power distribution system was discussed. Problems with power quality that result in loss of production to critical processes are costly and create a problem for the customer as well as the electric utility. Westinghouse has developed power quality improvement equipment for customers and utilities, using new technologies based on power electronics concepts. The Distribution Static Compensator (DSTATCOM) is a fast response, solid-state power controller that provides flexible voltage control for improving power quality at the point of connection to the utility`s 4.16 to 69 kV distribution feeder. STATCOM is a larger version of the DSTATCOM that can be used to solve voltage flicker problems caused by electric arc furnaces. Westinghouse has also developed a Dynamic Voltage Restorer (DVR) which protects a critical customer plant load from power system voltage disturbances. Solid-State Breakers (SSB) have also been developed which offer a solution to many of the distribution system problems that result in voltage sags, swells, and power outages. 6 refs., 8 figs.

  10. Air quality management: challenges and solutions in delivering air quality action plans

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, C.I.; Longhurst, J.W.S.; Woodfield, N.K.

    2000-07-01

    The Air Quality Strategy for England, Scotland, Wales and Northern Ireland (DETR, 2001) has the aim of showing how improved local air quality in the UK may be delivered. Through a process of reviewing and assessing local air quality in both urban and rural localities, a clear picture is emerging of areas of the UK where air quality objectives are not likely to be met. The next challenge will be the identification of the required actions and new ways of working to achieve specific air quality objectives. The declaration of air quality management areas, where objectives are not predicted to be met by their target years, involves co-ordinated local action and collaborative working, which can only be effective with support across local authority departments and external stake holders. This paper provides a background to the relevant legislation underpinning, local air quality management and summarises the review and assessment process. It then comments on future directions in relation to the designation of Air Quality Management Areas and considers the requirements of action plans to deliver the goal of cleaner air in the UK. It is concluded that the UK has developed a highly sophisticated system of air quality management over a relatively short period of time, and with it has brought a new way of local authority working. The challenge of the next stage of the process is likely to be in implementing cost effective and proportional solutions to identified problems at the local level. (Author)

  11. Heuristics for Multidimensional Packing Problems

    DEFF Research Database (Denmark)

    Egeblad, Jens

    for a minimum height container required for the items. The main contributions of the thesis are three new heuristics for strip-packing and knapsack packing problems where items are both rectangular and irregular. In the two first papers we describe a heuristic for the multidimensional strip-packing problem...... that is based on a relaxed placement principle. The heuristic starts with a random overlapping placement of items and large container dimensions. From the overlapping placement overlap is reduced iteratively until a non-overlapping placement is found and a new problem is solved with a smaller container size...... of this heuristic are among the best published in the literature both for two- and three-dimensional strip-packing problems for irregular shapes. In the third paper, we introduce a heuristic for two- and three-dimensional rectangular knapsack packing problems. The two-dimensional heuristic uses the sequence pair...

  12. Quality Scalability Compression on Single-Loop Solution in HEVC

    Directory of Open Access Journals (Sweden)

    Mengmeng Zhang

    2014-01-01

    Full Text Available This paper proposes a quality scalable extension design for the upcoming high efficiency video coding (HEVC standard. In the proposed design, the single-loop decoder solution is extended into the proposed scalable scenario. A novel interlayer intra/interprediction is added to reduce the amount of bits representation by exploiting the correlation between coding layers. The experimental results indicate that the average Bjøntegaard delta rate decrease of 20.50% can be gained compared with the simulcast encoding. The proposed technique achieved 47.98% Bjøntegaard delta rate reduction compared with the scalable video coding extension of the H.264/AVC. Consequently, significant rate savings confirm that the proposed method achieves better performance.

  13. A new Nawaz-Enscore-Ham-based heuristic for permutation flow-shop problems with bicriteria of makespan and machine idle time

    Science.gov (United States)

    Liu, Weibo; Jin, Yan; Price, Mark

    2016-10-01

    A new heuristic based on the Nawaz-Enscore-Ham algorithm is proposed in this article for solving a permutation flow-shop scheduling problem. A new priority rule is proposed by accounting for the average, mean absolute deviation, skewness and kurtosis, in order to fully describe the distribution style of processing times. A new tie-breaking rule is also introduced for achieving effective job insertion with the objective of minimizing both makespan and machine idle time. Statistical tests illustrate better solution quality of the proposed algorithm compared to existing benchmark heuristics.

  14. Heuristics and Cognitive Error in Medical Imaging.

    Science.gov (United States)

    Itri, Jason N; Patel, Sohil H

    2018-05-01

    The field of cognitive science has provided important insights into mental processes underlying the interpretation of imaging examinations. Despite these insights, diagnostic error remains a major obstacle in the goal to improve quality in radiology. In this article, we describe several types of cognitive bias that lead to diagnostic errors in imaging and discuss approaches to mitigate cognitive biases and diagnostic error. Radiologists rely on heuristic principles to reduce complex tasks of assessing probabilities and predicting values into simpler judgmental operations. These mental shortcuts allow rapid problem solving based on assumptions and past experiences. Heuristics used in the interpretation of imaging studies are generally helpful but can sometimes result in cognitive biases that lead to significant errors. An understanding of the causes of cognitive biases can lead to the development of educational content and systematic improvements that mitigate errors and improve the quality of care provided by radiologists.

  15. A perturbative clustering hyper-heuristic framework for the Danish railway system

    DEFF Research Database (Denmark)

    M. Pour, Shahrzad; Rasmussen, Kourosh Marjani; Burke, Edmund K.

    , we propose a perturbative clustering hyper-heuristic framework. The framework improves an initial solution by reassigning outliers (those tasks that are far away) to a better cluster choice at each iteration while taking balanced crews workloads into account. The framework introduces five lowlevel...... heuristics and employs an adaptive choice function as a robust learning mechanism. The results of adaptive clustering hyper-heuristic are compared with two exact and heuristic assignment algorithms from the literature and with the random hyper-heuristic framework on 12 datasets. In comparison with the exact...... formulation, the proposed framework could obtain promising results and solved the data instances up to 5000 number of tasks. In comparison with heuristic assignment and the random hyper-heuristic, the framework yielded approximately 11%, 27% and 10%,13% mprovement on total distance and the maximum distance...

  16. Impact of heuristics in clustering large biological networks.

    Science.gov (United States)

    Shafin, Md Kishwar; Kabir, Kazi Lutful; Ridwan, Iffatur; Anannya, Tasmiah Tamzid; Karim, Rashid Saadman; Hoque, Mohammad Mozammel; Rahman, M Sohel

    2015-12-01

    Traditional clustering algorithms often exhibit poor performance for large networks. On the contrary, greedy algorithms are found to be relatively efficient while uncovering functional modules from large biological networks. The quality of the clusters produced by these greedy techniques largely depends on the underlying heuristics employed. Different heuristics based on different attributes and properties perform differently in terms of the quality of the clusters produced. This motivates us to design new heuristics for clustering large networks. In this paper, we have proposed two new heuristics and analyzed the performance thereof after incorporating those with three different combinations in a recently celebrated greedy clustering algorithm named SPICi. We have extensively analyzed the effectiveness of these new variants. The results are found to be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Exact and Heuristic Algorithms for Runway Scheduling

    Science.gov (United States)

    Malik, Waqar A.; Jung, Yoon C.

    2016-01-01

    This paper explores the Single Runway Scheduling (SRS) problem with arrivals, departures, and crossing aircraft on the airport surface. Constraints for wake vortex separations, departure area navigation separations and departure time window restrictions are explicitly considered. The main objective of this research is to develop exact and heuristic based algorithms that can be used in real-time decision support tools for Air Traffic Control Tower (ATCT) controllers. The paper provides a multi-objective dynamic programming (DP) based algorithm that finds the exact solution to the SRS problem, but may prove unusable for application in real-time environment due to large computation times for moderate sized problems. We next propose a second algorithm that uses heuristics to restrict the search space for the DP based algorithm. A third algorithm based on a combination of insertion and local search (ILS) heuristics is then presented. Simulation conducted for the east side of Dallas/Fort Worth International Airport allows comparison of the three proposed algorithms and indicates that the ILS algorithm performs favorably in its ability to find efficient solutions and its computation times.

  18. A general heuristic for genome rearrangement problems.

    Science.gov (United States)

    Dias, Ulisses; Galvão, Gustavo Rodrigues; Lintzmayer, Carla Négri; Dias, Zanoni

    2014-06-01

    In this paper, we present a general heuristic for several problems in the genome rearrangement field. Our heuristic does not solve any problem directly, it is rather used to improve the solutions provided by any non-optimal algorithm that solve them. Therefore, we have implemented several algorithms described in the literature and several algorithms developed by ourselves. As a whole, we implemented 23 algorithms for 9 well known problems in the genome rearrangement field. A total of 13 algorithms were implemented for problems that use the notions of prefix and suffix operations. In addition, we worked on 5 algorithms for the classic problem of sorting by transposition and we conclude the experiments by presenting results for 3 approximation algorithms for the sorting by reversals and transpositions problem and 2 approximation algorithms for the sorting by reversals problem. Another algorithm with better approximation ratio can be found for the last genome rearrangement problem, but it is purely theoretical with no practical implementation. The algorithms we implemented in addition to our heuristic lead to the best practical results in each case. In particular, we were able to improve results on the sorting by transpositions problem, which is a very special case because many efforts have been made to generate algorithms with good results in practice and some of these algorithms provide results that equal the optimum solutions in many cases. Our source codes and benchmarks are freely available upon request from the authors so that it will be easier to compare new approaches against our results.

  19. Heuristics Reasoning in Diagnostic Judgment.

    Science.gov (United States)

    O'Neill, Eileen S.

    1995-01-01

    Describes three heuristics--short-cut mental strategies that streamline information--relevant to diagnostic reasoning: accessibility, similarity, and anchoring and adjustment. Analyzes factors thought to influence heuristic reasoning and presents interventions to be tested for nursing practice and education. (JOW)

  20. Reexamining Our Bias against Heuristics

    Science.gov (United States)

    McLaughlin, Kevin; Eva, Kevin W.; Norman, Geoff R.

    2014-01-01

    Using heuristics offers several cognitive advantages, such as increased speed and reduced effort when making decisions, in addition to allowing us to make decision in situations where missing data do not allow for formal reasoning. But the traditional view of heuristics is that they trade accuracy for efficiency. Here the authors discuss sources…

  1. HEURISTIC APPROACHES FOR PORTFOLIO OPTIMIZATION

    OpenAIRE

    Manfred Gilli, Evis Kellezi

    2000-01-01

    The paper first compares the use of optimization heuristics to the classical optimization techniques for the selection of optimal portfolios. Second, the heuristic approach is applied to problems other than those in the standard mean-variance framework where the classical optimization fails.

  2. Heuristic algorithms for joint optimization of unicast and anycast traffic in elastic optical network–based large–scale computing systems

    Directory of Open Access Journals (Sweden)

    Markowski Marcin

    2017-09-01

    Full Text Available In recent years elastic optical networks have been perceived as a prospective choice for future optical networks due to better adjustment and utilization of optical resources than is the case with traditional wavelength division multiplexing networks. In the paper we investigate the elastic architecture as the communication network for distributed data centers. We address the problems of optimization of routing and spectrum assignment for large-scale computing systems based on an elastic optical architecture; particularly, we concentrate on anycast user to data center traffic optimization. We assume that computational resources of data centers are limited. For this offline problems we formulate the integer linear programming model and propose a few heuristics, including a meta-heuristic algorithm based on a tabu search method. We report computational results, presenting the quality of approximate solutions and efficiency of the proposed heuristics, and we also analyze and compare some data center allocation scenarios.

  3. Usable guidelines for usable websites? an analysis of five e-government heuristics

    NARCIS (Netherlands)

    Welle Donker-Kuijer, M.C.J.; de Jong, Menno D.T.; Lentz, Leo

    2010-01-01

    Many government organizations use web heuristics for the quality assurance of their websites. Heuristics may be used by web designers to guide the decisions about a website in development, or by web evaluators to optimize or assess the quality of an existing website. Despite their popularity, very

  4. Performance of Optimization Heuristics for the Operational Planning of Multi-energy Storage Systems

    Science.gov (United States)

    Haas, J.; Schradi, J.; Nowak, W.

    2016-12-01

    In the transition to low-carbon energy sources, energy storage systems (ESS) will play an increasingly important role. Particularly in the context of solar power challenges (variability, uncertainty), ESS can provide valuable services: energy shifting, ramping, robustness against forecast errors, frequency support, etc. However, these qualities are rarely modelled in the operational planning of power systems because of the involved computational burden, especially when multiple ESS technologies are involved. This work assesses two optimization heuristics for speeding up the optimal operation problem. It compares their accuracy (in terms of costs) and speed against a reference solution. The first heuristic (H1) is based on a merit order. Here, the ESS are sorted from lower to higher operational costs (including cycling costs). For each time step, the cheapest available ESS is used first, followed by the second one and so on, until matching the net load (demand minus available renewable generation). The second heuristic (H2) uses the Fourier transform to detect the main frequencies that compose the net load. A specific ESS is assigned to each frequency range, aiming to smoothen the net load. Finally, the reference solution is obtained with a mixed integer linear program (MILP). H1, H2 and MILP are subject to technical constraints (energy/power balance, ramping rates, on/off states...). Costs due to operation, replacement (cycling) and unserved energy are considered. Four typical days of a system with a high share of solar energy were used in several test cases, varying the resolution from one second to fifteen minutes. H1 and H2 achieve accuracies of about 90% and 95% in average, and speed-up times of two to three and one to two orders of magnitude, respectively. The use of the heuristics looks promising in the context of planning the expansion of power systems, especially when their loss of accuracy is outweighed by solar or wind forecast errors.

  5. Paranoid thinking as a heuristic.

    Science.gov (United States)

    Preti, Antonio; Cella, Matteo

    2010-08-01

    Paranoid thinking can be viewed as a human heuristic used by individuals to deal with uncertainty during stressful situations. Under stress, individuals are likely to emphasize the threatening value of neutral stimuli and increase the reliance on paranoia-based heuristic to interpreter events and guide their decisions. Paranoid thinking can also be activated by stress arising from the possibility of losing a good opportunity; this may result in an abnormal allocation of attentional resources to social agents. A better understanding of the interplay between cognitive heuristics and emotional processes may help to detect situations in which paranoid thinking is likely to exacerbate and improve intervention for individuals with delusional disorders.

  6. An efficient heuristic versus a robust hybrid meta-heuristic for general framework of serial-parallel redundancy problem

    International Nuclear Information System (INIS)

    Sadjadi, Seyed Jafar; Soltani, R.

    2009-01-01

    We present a heuristic approach to solve a general framework of serial-parallel redundancy problem where the reliability of the system is maximized subject to some general linear constraints. The complexity of the redundancy problem is generally considered to be NP-Hard and the optimal solution is not normally available. Therefore, to evaluate the performance of the proposed method, a hybrid genetic algorithm is also implemented whose parameters are calibrated via Taguchi's robust design method. Then, various test problems are solved and the computational results indicate that the proposed heuristic approach could provide us some promising reliabilities, which are fairly close to optimal solutions in a reasonable amount of time.

  7. Heuristic introduction to gravitational waves

    International Nuclear Information System (INIS)

    Sandberg, V.D.

    1982-01-01

    The purpose of this article is to provide a rough and somewhat heuristic theoretical background and introduction to gravitational radiation, its generation, and its detection based on Einstein's general theory of relativity

  8. Heuristic reasoning and relative incompleteness

    OpenAIRE

    Treur, J.

    1993-01-01

    In this paper an approach is presented in which heuristic reasoning is interpreted as strategic reasoning. This type of reasoning enables one to derive which hypothesis to investigate, and which observable information to acquire next (to be able to verify the chosen hypothesis). A compositional architecture for reasoning systems that perform such heuristic reasoning is introduced, called SIX (for Strategic Interactive eXpert systems). This compositional architecture enables user interaction a...

  9. Modified strip packing heuristics for the rectangular variable-sized bin packing problem

    Directory of Open Access Journals (Sweden)

    FG Ortmann

    2010-06-01

    Full Text Available Two packing problems are considered in this paper, namely the well-known strip packing problem (SPP and the variable-sized bin packing problem (VSBPP. A total of 252 strip packing heuristics (and variations thereof from the literature, as well as novel heuristics proposed by the authors, are compared statistically by means of 1170 SPP benchmark instances in order to identify the best heuristics in various classes. A combination of new heuristics with a new sorting method yields the best results. These heuristics are combined with a previous heuristic for the VSBPP by the authors to find good feasible solutions to 1357 VSBPP benchmark instances. This is the largest statistical comparison of algorithms for the SPP and the VSBPP to the best knowledge of the authors.

  10. Heuristic and optimal policy computations in the human brain during sequential decision-making.

    Science.gov (United States)

    Korn, Christoph W; Bach, Dominik R

    2018-01-23

    Optimal decisions across extended time horizons require value calculations over multiple probabilistic future states. Humans may circumvent such complex computations by resorting to easy-to-compute heuristics that approximate optimal solutions. To probe the potential interplay between heuristic and optimal computations, we develop a novel sequential decision-making task, framed as virtual foraging in which participants have to avoid virtual starvation. Rewards depend only on final outcomes over five-trial blocks, necessitating planning over five sequential decisions and probabilistic outcomes. Here, we report model comparisons demonstrating that participants primarily rely on the best available heuristic but also use the normatively optimal policy. FMRI signals in medial prefrontal cortex (MPFC) relate to heuristic and optimal policies and associated choice uncertainties. Crucially, reaction times and dorsal MPFC activity scale with discrepancies between heuristic and optimal policies. Thus, sequential decision-making in humans may emerge from integration between heuristic and optimal policies, implemented by controllers in MPFC.

  11. Comparative study of heuristics algorithms in solving flexible job shop scheduling problem with condition based maintenance

    Directory of Open Access Journals (Sweden)

    Yahong Zheng

    2014-05-01

    Full Text Available Purpose: This paper focuses on a classic optimization problem in operations research, the flexible job shop scheduling problem (FJSP, to discuss the method to deal with uncertainty in a manufacturing system.Design/methodology/approach: In this paper, condition based maintenance (CBM, a kind of preventive maintenance, is suggested to reduce unavailability of machines. Different to the simultaneous scheduling algorithm (SSA used in the previous article (Neale & Cameron,1979, an inserting algorithm (IA is applied, in which firstly a pre-schedule is obtained through heuristic algorithm and then maintenance tasks are inserted into the pre-schedule scheme.Findings: It is encouraging that a new better solution for an instance in benchmark of FJSP is obtained in this research. Moreover, factually SSA used in literature for solving normal FJSPPM (FJSP with PM is not suitable for the dynamic FJSPPM. Through application in the benchmark of normal FJSPPM, it is found that although IA obtains inferior results compared to SSA used in literature, it performs much better in executing speed.Originality/value: Different to traditional scheduling of FJSP, uncertainty of machines is taken into account, which increases the complexity of the problem. An inserting algorithm (IA is proposed to solve the dynamic scheduling problem. It is stated that the quality of the final result depends much on the quality of the pre-schedule obtained during the procedure of solving a normal FJSP. In order to find the best solution of FJSP, a comparative study of three heuristics is carried out, the integrated GA, ACO and ABC. In the comparative study, we find that GA performs best in the three heuristic algorithms. Meanwhile, a new better solution for an instance in benchmark of FJSP is obtained in this research.

  12. Experimental evidence for convergent evolution of maternal care heuristics in industrialized and small-scale populations.

    Science.gov (United States)

    Kushnick, Geoff; Hanowell, Ben; Kim, Jun-Hong; Langstieh, Banrida; Magnano, Vittorio; Oláh, Katalin

    2015-06-01

    Maternal care decision rules should evolve responsiveness to factors impinging on the fitness pay-offs of care. Because the caretaking environments common in industrialized and small-scale societies vary in predictable ways, we hypothesize that heuristics guiding maternal behaviour will also differ between these two types of populations. We used a factorial vignette experiment to elicit third-party judgements about likely caretaking decisions of a hypothetical mother and her child when various fitness-relevant factors (maternal age and access to resources, and offspring age, sex and quality) were varied systematically in seven populations-three industrialized and four small-scale. Despite considerable variation in responses, we found that three of five main effects, and the two severity effects, exhibited statistically significant industrialized/ small-scale population differences. All differences could be explained as adaptive solutions to industrialized versus small-scale caretaking environments. Further, we found gradients in the relationship between the population-specific estimates and national-level socio-economic indicators, further implicating important aspects of the variation in industrialized and small-scale caretaking environments in shaping heuristics. Although there is mounting evidence for a genetic component to human maternal behaviour, there is no current evidence for interpopulation variation in candidate genes. We nonetheless suggest that heuristics guiding maternal behaviour in diverse societies emerge via convergent evolution in response to similar selective pressures.

  13. A greedy construction heuristic for the liner service network design problem

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard

    is challenging due to the size of a global liner shipping operation and due to the hub-and-spoke network design, where a high percentage of the total cargo is transshipped. We present the first construction heuristic for large scale instances of the LSN-DP. The heuristic is able to find a solution for a real...

  14. An adaptive large neighborhood search heuristic for the Electric Vehicle Scheduling Problem

    DEFF Research Database (Denmark)

    Wen, M.; Linde, Esben; Røpke, Stefan

    2016-01-01

    to minimizing the total deadheading distance. A mixed integer programming formulation as well as an Adaptive Large Neighborhood Search (ALNS) heuristic for the E-VSP are presented. ALNS is tested on newly generated E-VSP benchmark instances. Result shows that the proposed heuristic can provide good solutions...

  15. A Comparison between Different Meta-Heuristic Techniques in Power Allocation for Physical Layer Security

    Directory of Open Access Journals (Sweden)

    N. Okati

    2017-12-01

    Full Text Available Node cooperation can protect wireless networks from eavesdropping by using the physical characteristics of wireless channels rather than cryptographic methods. Allocating the proper amount of power to cooperative nodes is a challenging task. In this paper, we use three cooperative nodes, one as relay to increase throughput at the destination and two friendly jammers to degrade eavesdropper’s link. For this scenario, the secrecy rate function is a non-linear non-convex problem. So, in this case, exact optimization methods can only achieve suboptimal solution. In this paper, we applied different meta-heuristic optimization techniques, like Genetic Algorithm (GA, Partial Swarm Optimization (PSO, Bee Algorithm (BA, Tabu Search (TS, Simulated Annealing (SA and Teaching-Learning-Based Optimization (TLBO. They are compared with each other to obtain solution for power allocation in a wiretap wireless network. Although all these techniques find suboptimal solutions, but they appear superlative to exact optimization methods. Finally, we define a Figure of Merit (FOM as a rule of thumb to determine the best meta-heuristic algorithm. This FOM considers quality of solution, number of required iterations to converge, and CPU time.

  16. Voltage quality: solutions of desensitization; Qualite de la tension: les solutions de desensibilisation

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1999-10-01

    The occurrence of voltage drops and cuts can lead to major malfunctions in electrical installations with sometimes important economical impacts. Thus, the use of solutions of desensitization are needed to avoid such disturbances. This technical paper gives a summary of the basic solutions elaborated by Electricite de France (EdF) with the participation of electrical engineering associations in order to solve the problems encountered in existing installations and to provide specifications for the newly designed installations: the desensitization process (origin of voltage drops, solutions, costs), the diagnosis of industrial installations (identification, quantitative analysis and recording of disturbances, complementary informations, causes, economical impact, solutions, costs, remedial action), the general and specific solutions of desensitization (instrumentation and control systems, switches, relays, motors, speed regulators and variators), specific solutions for computerized and electronic systems, and the role of batteries. (J.S.)

  17. Heuristic space diversity management in a meta-hyper-heuristic framework

    CSIR Research Space (South Africa)

    Grobler, J

    2014-07-01

    Full Text Available This paper introduces the concept of heuristic space diversity and investigates various strategies for the management of heuristic space diversity within the context of a meta-hyper-heuristic algorithm. Evaluation on a diverse set of floating...

  18. Heuristic space diversity control for improved meta-hyper-heuristic performance

    CSIR Research Space (South Africa)

    Grobler, J

    2015-04-01

    Full Text Available This paper expands on the concept of heuristic space diversity and investigates various strategies for the management of heuristic space diversity within the context of a meta-hyper-heuristic algorithm in search of greater performance benefits...

  19. Quality improvement in food value chains: searching for integrated solutions

    NARCIS (Netherlands)

    Bijman, J.; Bitzer, V.

    2016-01-01

    Quality improvement in food value chains offers both opportunities and challenges for farmers in Africa. This chapter introduces the key concepts that are used in the studies presented in this book. It also provides a short description of each of the chapters. Quality is an elusive concept. It has a

  20. Prototypes Are Key Heuristic Information in Insight Problem Solving

    Science.gov (United States)

    Yang, Wenjing; Dietrich, Arne; Liu, Peiduo; Ming, Dan; Jin, Yule; Nusbaum, Howard C.; Qiu, Jiang; Zhang, Qinglin

    2016-01-01

    Evidence from a range of fields indicates that inventions are often inspired by drawing a parallel to solutions found in nature. However, the cognitive mechanism of this process is not well understood. The cognitive mechanism of heuristic prototype in scientific innovation was tested with 3 experiments. First, 84 historical accounts of important…

  1. Solution of electric power quality problems by troika cooperation

    International Nuclear Information System (INIS)

    Khan, N.; Ahmad, M.I.

    1999-01-01

    Power quality is a growing concern effecting utility supply continuity, sensitivity customer productivity and manufacturer equipment. Power quality problems such as voltage sags, swells, distortions and transient surges caused by short circuit faults or motor starting, switching reactive loads or phase to ground faults. VSD or arcing loads and inductive or capacity load switching may result in process shutdown or contactor dropout, under voltage tripping and speed drift or ASD tripping. This work describes results of a power quality study concluding urgent need for enhancing cooperation between utilities, customers and manufactures to improve power quality problems. Individual responsibilities of utilities personnel, sensitive equipment customers and power equipment manufacturers in light of available power conditioning technology, regarding deployment of equipment and improvement of design strategies have been discussed for precious end users. (authors)

  2. Heuristic errors in clinical reasoning.

    Science.gov (United States)

    Rylander, Melanie; Guerrasio, Jeannette

    2016-08-01

    Errors in clinical reasoning contribute to patient morbidity and mortality. The purpose of this study was to determine the types of heuristic errors made by third-year medical students and first-year residents. This study surveyed approximately 150 clinical educators inquiring about the types of heuristic errors they observed in third-year medical students and first-year residents. Anchoring and premature closure were the two most common errors observed amongst third-year medical students and first-year residents. There was no difference in the types of errors observed in the two groups. Errors in clinical reasoning contribute to patient morbidity and mortality Clinical educators perceived that both third-year medical students and first-year residents committed similar heuristic errors, implying that additional medical knowledge and clinical experience do not affect the types of heuristic errors made. Further work is needed to help identify methods that can be used to reduce heuristic errors early in a clinician's education. © 2015 John Wiley & Sons Ltd.

  3. A greedy double swap heuristic for nurse scheduling

    Directory of Open Access Journals (Sweden)

    Murphy Choy

    2012-10-01

    Full Text Available One of the key challenges of nurse scheduling problem (NSP is the number of constraints placed on preparing the timetable, both from the regulatory requirements as well as the patients’ demand for the appropriate nursing care specialists. In addition, the preferences of the nursing staffs related to their work schedules add another dimension of complexity. Most solutions proposed for solving nurse scheduling involve the use of mathematical programming and generally considers only the hard constraints. However, the psychological needs of the nurses are ignored and this resulted in subsequent interventions by the nursing staffs to remedy any deficiency and often results in last minute changes to the schedule. In this paper, we present a staff preference optimization framework solved with a greedy double swap heuristic. The heuristic yields good performance in speed at solving the problem. The heuristic is simple and we will demonstrate its performance by implementing it on open source spreadsheet software.

  4. Heuristic Search Theory and Applications

    CERN Document Server

    Edelkamp, Stefan

    2011-01-01

    Search has been vital to artificial intelligence from the very beginning as a core technique in problem solving. The authors present a thorough overview of heuristic search with a balance of discussion between theoretical analysis and efficient implementation and application to real-world problems. Current developments in search such as pattern databases and search with efficient use of external memory and parallel processing units on main boards and graphics cards are detailed. Heuristic search as a problem solving tool is demonstrated in applications for puzzle solving, game playing, constra

  5. Using heuristics to solve the dedicated aircraft recovery problem

    DEFF Research Database (Denmark)

    Løve, Michael; Sørensen, Kim Riis; Larsen, Jesper

    2001-01-01

    schedules through a series of reassignments of aircraft to flights, delaying of flights and cancellations of flights. This article describes an effective method to solve DARP. A heuristic is implemented, which is able to generate feasible revised flight schedules of good quality in less than 10 seconds when...... applied to real flight schedules with disruptions from British Airways. The heuristic is able to consider delays, cancellations and reassignments simultaneously and balance the trade-off between these options. It is also demonstrated that different strategies can be applied to prioritize these options...

  6. Emerging melt quality control solution technologies for aluminium melt

    Directory of Open Access Journals (Sweden)

    Arturo Pascual, Jr

    2009-11-01

    Full Text Available The newly developed “MTS 1500” Melt Treatment System is performing the specifi cally required melt treatment operations like degassing, cleaning, modification and/or grain refinement by an automated process in one step and at the same location. This linked process is saving time, energy and metal losses allowing - by automated dosage of the melt treatment agents - the production of a consistent melt quality batch after batch. By linking the MTS Metal Treatment System with sensors operating on-line in the melt, i.e., with a hydrogen sensor “Alspek H”, a fully automated control of parts of the process chain like degassing is possible. This technology does guarantee a pre-specifi ed and documented melt quality in each melt treatment batch. Furthermore, to ensure that castings are consistent and predictable there is a growing realization that critical parameters such as metal cleanliness must be measured prior to casting. There exists accepted methods for measuring the cleanliness of an aluminum melt but these can be both slow and costly. A simple, rapid and meaningful method of measuring and bench marking the cleanliness of an aluminum melt has been developed to offer the foundry a practical method of measuring melt cleanliness. This paper shows the structure and performance of the integrated MTS melt treatment process and documents achieved melt quality standards after degassing, cleaning, modifi cation and grain refi nement operations under real foundry conditions. It also provides an insight on a melt cleanliness measuring device “Alspek MQ” to provide foundry men better tools in meeting the increasing quality and tighter specifi cation demand from the industry.

  7. Heuristic Biases in Mathematical Reasoning

    Science.gov (United States)

    Inglis, Matthew; Simpson, Adrian

    2005-01-01

    In this paper we briefly describe the dual process account of reasoning, and explain the role of heuristic biases in human thought. Concentrating on the so-called matching bias effect, we describe a piece of research that indicates a correlation between success at advanced level mathematics and an ability to override innate and misleading…

  8. Heuristic reasoning and relative incompleteness

    NARCIS (Netherlands)

    Treur, J.

    1993-01-01

    In this paper an approach is presented in which heuristic reasoning is interpreted as strategic reasoning. This type of reasoning enables one to derive which hypothesis to investigate, and which observable information to acquire next (to be able to verify the chosen hypothesis). A compositional

  9. Exact Solutions to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Archetti, Claudia; Madsen, Oli B.G.

    In the Double Travelling Salesman Problem with Multiple Stacks (DTSPMS) a set of orders is given, each one requiring transportation of one item from a customer in a pickup region to a customer in a delivery region. The vehicle available for the transportation in each region carries a container....... We present different modelling approaches to solving the DTSPMS to optimality and use the solutions obtained to evaluate the quality of previously obtained heuristic solutions....

  10. Should We Stop Developing Heuristics and Only Rely on Mixed Integer Programming Solvers in Automated Test Assembly? A Rejoinder to van der Linden and Li (2016).

    Science.gov (United States)

    Chen, Pei-Hua

    2017-05-01

    This rejoinder responds to the commentary by van der Linden and Li entiled "Comment on Three-Element Item Selection Procedures for Multiple Forms Assembly: An Item Matching Approach" on the article "Three-Element Item Selection Procedures for Multiple Forms Assembly: An Item Matching Approach" by Chen. Van der Linden and Li made a strong statement calling for the cessation of test assembly heuristics development, and instead encouraged embracing mixed integer programming (MIP). This article points out the nondeterministic polynomial (NP)-hard nature of MIP problems and how solutions found using heuristics could be useful in an MIP context. Although van der Linden and Li provided several practical examples of test assembly supporting their view, the examples ignore the cases in which a slight change of constraints or item pool data might mean it would not be possible to obtain solutions as quickly as before. The article illustrates the use of heuristic solutions to improve both the performance of MIP solvers and the quality of solutions. Additional responses to the commentary by van der Linden and Li are included.

  11. A priority-based heuristic algorithm (PBHA for optimizing integrated process planning and scheduling problem

    Directory of Open Access Journals (Sweden)

    Muhammad Farhan Ausaf

    2015-12-01

    Full Text Available Process planning and scheduling are two important components of a manufacturing setup. It is important to integrate them to achieve better global optimality and improved system performance. To find optimal solutions for integrated process planning and scheduling (IPPS problem, numerous algorithm-based approaches exist. Most of these approaches try to use existing meta-heuristic algorithms for solving the IPPS problem. Although these approaches have been shown to be effective in optimizing the IPPS problem, there is still room for improvement in terms of quality of solution and algorithm efficiency, especially for more complicated problems. Dispatching rules have been successfully utilized for solving complicated scheduling problems, but haven’t been considered extensively for the IPPS problem. This approach incorporates dispatching rules with the concept of prioritizing jobs, in an algorithm called priority-based heuristic algorithm (PBHA. PBHA tries to establish job and machine priority for selecting operations. Priority assignment and a set of dispatching rules are simultaneously used to generate both the process plans and schedules for all jobs and machines. The algorithm was tested for a series of benchmark problems. The proposed algorithm was able to achieve superior results for most complex problems presented in recent literature while utilizing lesser computational resources.

  12. An effective heuristic for combined heat-and-power production planning with power ramp constraints

    International Nuclear Information System (INIS)

    Rong, Aiying; Lahdelma, Risto

    2007-01-01

    Combined heat-and-power (CHP) production is an increasingly important technology for its efficient utilization of primary-energy resources and for reducing CO 2 emissions. In the CHP plant, the generation of heat-and-power follows a joint characteristic, which makes the determination of both the marginal power production cost (MPPC) and the feasible operating region for the plant more complicated than for the power-only generation plant. Due to the interdependence between heat and power production, the power-ramp constraints, which limit how much the power production of a CHP plant may increase or decrease between two successive periods, may also imply constraints on the heat production. In this paper, we investigate the impact of power-ramp constraints on CHP production planning and develop a robust heuristic for dealing with the power-ramp constraints based on the solution to the problem with relaxed ramp-constraints (RRC). Numerical results based on realistic production models show that the heuristic can generate high-quality solutions efficiently. (author)

  13. A Hybrid Heuristic Approach to Provider Selection and Task Allocation Problem in Telecommunications with Varying QoS Levels

    Directory of Open Access Journals (Sweden)

    Nihat Kasap

    2017-01-01

    Full Text Available In this research, we study a cost minimization problem for a firm that acquires capacity from providers to accomplish daily operations on telecommunication networks. We model the related optimization problem considering quality of service and capacity requirements and offer a solution approach based on genetic algorithm (GA. Our model reckons the tradeoff between the network capacity acquisition cost and opportunity cost arise when data transmission quality for real-time tasks manifested at undesired levels. To better represent the related features and complexities, we model both capacity and loss probability requirements explicitly, and then, formulate delay and jitter requirements as level matching constraints. Using an experimental framework, we analyze how optimal behavior of the firm is affected by different price schemes, transmission quality and task distributions. We also compare three GA based heuristic solution approaches and comment on the suitability of them on resource selection and task allocation problems.

  14. Familiarity and recollection in heuristic decision making.

    Science.gov (United States)

    Schwikert, Shane R; Curran, Tim

    2014-12-01

    Heuristics involve the ability to utilize memory to make quick judgments by exploiting fundamental cognitive abilities. In the current study we investigated the memory processes that contribute to the recognition heuristic and the fluency heuristic, which are both presumed to capitalize on the byproducts of memory to make quick decisions. In Experiment 1, we used a city-size comparison task while recording event-related potentials (ERPs) to investigate the potential contributions of familiarity and recollection to the 2 heuristics. ERPs were markedly different for recognition heuristic-based decisions and fluency heuristic-based decisions, suggesting a role for familiarity in the recognition heuristic and recollection in the fluency heuristic. In Experiment 2, we coupled the same city-size comparison task with measures of subjective preexperimental memory for each stimulus in the task. Although previous literature suggests the fluency heuristic relies on recognition speed alone, our results suggest differential contributions of recognition speed and recollected knowledge to these decisions, whereas the recognition heuristic relies on familiarity. Based on these results, we created a new theoretical framework that explains decisions attributed to both heuristics based on the underlying memory associated with the choice options. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  15. Special relativity a heuristic approach

    CERN Document Server

    Hassani, Sadri

    2017-01-01

    Special Relativity: A Heuristic Approach provides a qualitative exposition of relativity theory on the basis of the constancy of the speed of light. Using Einstein's signal velocity as the defining idea for the notion of simultaneity and the fact that the speed of light is independent of the motion of its source, chapters delve into a qualitative exposition of the relativity of time and length, discuss the time dilation formula using the standard light clock, explore the Minkowski four-dimensional space-time distance based on how the time dilation formula is derived, and define the components of the two-dimensional space-time velocity, amongst other topics. Provides a heuristic derivation of the Minkowski distance formula Uses relativistic photography to see Lorentz transformation and vector algebra manipulation in action Includes worked examples to elucidate and complement the topic being discussed Written in a very accessible style

  16. Multiobjective hyper heuristic scheme for system design and optimization

    Science.gov (United States)

    Rafique, Amer Farhan

    2012-11-01

    As system design is becoming more and more multifaceted, integrated, and complex, the traditional single objective optimization trends of optimal design are becoming less and less efficient and effective. Single objective optimization methods present a unique optimal solution whereas multiobjective methods present pareto front. The foremost intent is to predict a reasonable distributed pareto-optimal solution set independent of the problem instance through multiobjective scheme. Other objective of application of intended approach is to improve the worthiness of outputs of the complex engineering system design process at the conceptual design phase. The process is automated in order to provide the system designer with the leverage of the possibility of studying and analyzing a large multiple of possible solutions in a short time. This article presents Multiobjective Hyper Heuristic Optimization Scheme based on low level meta-heuristics developed for the application in engineering system design. Herein, we present a stochastic function to manage meta-heuristics (low-level) to augment surety of global optimum solution. Generic Algorithm, Simulated Annealing and Swarm Intelligence are used as low-level meta-heuristics in this study. Performance of the proposed scheme is investigated through a comprehensive empirical analysis yielding acceptable results. One of the primary motives for performing multiobjective optimization is that the current engineering systems require simultaneous optimization of conflicting and multiple. Random decision making makes the implementation of this scheme attractive and easy. Injecting feasible solutions significantly alters the search direction and also adds diversity of population resulting in accomplishment of pre-defined goals set in the proposed scheme.

  17. THE DISCRETE TIME, COST AND QUALITY TRADE-OFF PROBLEM IN PROJECT SCHEDULING: AN EFFICIENT SOLUTION METHOD BASED ON CELLDE ALGORITHM

    Directory of Open Access Journals (Sweden)

    Gh. Assadipour

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT:The trade-off between time, cost, and quality is one of the important problems of project management. This problem assumes that all project activities can be executed in different modes of cost, time, and quality. Thus a manager should select each activity’s mode such that the project can meet the deadline with the minimum possible cost and the maximum achievable quality. As the problem is NP-hard and the objectives are in conflict with each other, a multi-objective meta-heuristic called CellDE, which is a hybrid cellular genetic algorithm, is implemented as the optimisation method. The proposed algorithm provides project managers with a set of non-dominated or Pareto-optimal solutions, and enables them to choose the best one according to their preferences. A set of problems of different sizes is generated and solved using the proposed algorithm. Three metrics are employed for evaluating the performance of the algorithm, appraising the diversity and convergence of the achieved Pareto fronts. Finally a comparison is made between CellDE and another meta-heuristic available in the literature. The results show the superiority of CellDE.

    AFRIKAANSE OPSOMMING: ‘n Balans tussen tyd, koste en gehalte is een van die belangrike probleme van projekbestuur. Die vraagstuk maak gewoonlik die aanname dat alle projekaktiwiteite uitgevoer kan word op uiteenlopende wyses wat verband hou met koste, tyd en gehalte. ‘n Projekbestuurder selekteer gewoonlik die uitvoeringsmetodes sodanig per aktiwiteit dat gehoor gegegee word aan minimum koste en maksimum gehalte teen die voorwaarde van voltooiingsdatum wat bereik moet word.

    Aangesien die beskrewe problem NP-hard is, word dit behandel ten opsigte van konflikterende doelwitte met ‘n multidoelwit metaheuristiese metode (CellDE. Die metode is ‘n hibride-sellulêre genetiese algoritme. Die algoritme lewer aan die besluitvormer ‘n versameling van ongedomineerde of Pareto

  18. A Computational Investigation of Heuristic Algorithms for 2-Edge-Connectivity Augmentation

    DEFF Research Database (Denmark)

    Bang-Jensen, Jørgen; Chiarandini, Marco; Morling, Peter

    2010-01-01

    an equivalent set covering   formulation.  The results indicate that exact solutions by means of a   basic integer programming model can be obtained in reasonably short   time even on networks with 800 vertices and around 287,000   edges. Alternatively, an advanced heuristic algorithm based on   subgradient...... programming, simple construction heuristics and   metaheuristics. As part of the design of heuristics, we consider   different neighborhood structures for local search, among which is a very   large scale neighborhood. In all cases, we exploit approaches through   the graph formulation as well as through...

  19. Comparing the performance of different meta-heuristics for unweighted parallel machine scheduling

    Directory of Open Access Journals (Sweden)

    Adamu, Mumuni Osumah

    2015-08-01

    Full Text Available This article considers the due window scheduling problem to minimise the number of early and tardy jobs on identical parallel machines. This problem is known to be NP complete and thus finding an optimal solution is unlikely. Three meta-heuristics and their hybrids are proposed and extensive computational experiments are conducted. The purpose of this paper is to compare the performance of these meta-heuristics and their hybrids and to determine the best among them. Detailed comparative tests have also been conducted to analyse the different heuristics with the simulated annealing hybrid giving the best result.

  20. Application of refractometry to quality assurance monitoring of parenteral nutrition solutions.

    Science.gov (United States)

    Chang, Wei-Kuo; Chao, You-Chen; Yeh, Ming-Kung

    2008-01-01

    Parenteral nutrition (PN) solution contains various concentrations of dextrose, amino acids, lipids, vitamins, electrolytes, and trace elements. Incorrect preparation of PN solution could lead to patient death. In this study we used the refractive index as a quality assurance tool to monitor the preparation of PN solution. Refractive indices of single nutrient components and PN solutions consisting of various concentrations of dextrose, amino acids, electrolytes, and lipids were measured. A mathematical equation and its linear plot were generated then used to predict the refractive index of the PN solution. The best-fit refractive index for PN solution (i.e., the predicted refractive index)=0.9798x(% dextrose)+1.2889x(% amino acids)+1.1017x(% lipids)+0.9440x(% sum of the electrolytes)+0.5367 (r2=0.99). This equation was validated by comparing the measured refractive indices of 500 clinical PN solutions to their predicted refractive indices. We found that 2 of the 500 prepared samples (0.4%) had less than the predicted refractive index (<95%). Refractive index can be used as a reliable quality assurance tool for monitoring PN preparation. Such information can be obtained at the bedside and used to confirm the accuracy of the PN solution composition.

  1. Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

    Science.gov (United States)

    Lee, Charles H.; Cheung, Kar-Ming

    2012-01-01

    In this paper, we propose to solve the constrained optimization problem in two phases. The first phase uses heuristic methods such as the ant colony method, particle swarming optimization, and genetic algorithm to seek a near optimal solution among a list of feasible initial populations. The final optimal solution can be found by using the solution of the first phase as the initial condition to the SQP algorithm. We demonstrate the above problem formulation and optimization schemes with a large-scale network that includes the DSN ground stations and a number of spacecraft of deep space missions.

  2. The use of meta-heuristics for airport gate assignment

    DEFF Research Database (Denmark)

    Cheng, Chun-Hung; Ho, Sin C.; Kwan, Cheuk-Lam

    2012-01-01

    proposed to generate good solutions within a reasonable timeframe. In this work, we attempt to assess the performance of three meta-heuristics, namely, genetic algorithm (GA), tabu search (TS), simulated annealing (SA) and a hybrid approach based on SA and TS. Flight data from Incheon International Airport...... are collected to carry out the computational comparison. Although the literature has documented these algorithms, this work may be a first attempt to evaluate their performance using a set of realistic flight data....

  3. Heuristics for NP-hard optimization problems - simpler is better!?

    Directory of Open Access Journals (Sweden)

    Žerovnik Janez

    2015-11-01

    Full Text Available We provide several examples showing that local search, the most basic metaheuristics, may be a very competitive choice for solving computationally hard optimization problems. In addition, generation of starting solutions by greedy heuristics should be at least considered as one of very natural possibilities. In this critical survey, selected examples discussed include the traveling salesman, the resource-constrained project scheduling, the channel assignment, and computation of bounds for the Shannon capacity.

  4. Problem specific heuristics for group scheduling problems in cellular manufacturing

    OpenAIRE

    Neufeld, Janis Sebastian

    2016-01-01

    The group scheduling problem commonly arises in cellular manufacturing systems, where parts are grouped into part families. It is characterized by a sequencing task on two levels: on the one hand, a sequence of jobs within each part family has to be identified while, on the other hand, a family sequence has to be determined. In order to solve this NP-hard problem usually heuristic solution approaches are used. In this thesis different aspects of group scheduling are discussed and problem spec...

  5. examining the predictive power of the VRIO-Framework and the Recognition Heuristic

    OpenAIRE

    Powalla, Christian

    2010-01-01

    Boundedly rational managers regularly have to make complex strategic decisions under uncertainty. In this context heuristics can play an important supporting role. They are used to reasonably structure the decision making process, to reduce the information search, and to achieve a good solution with an acceptable problem-solving effort. This empirical research project analyzes the practical usefulness of several selected heuristic techniques, which can be used within strategic analysis, by...

  6. Heuristic algorithm for single resource constrained project scheduling problem based on the dynamic programming

    Directory of Open Access Journals (Sweden)

    Stanimirović Ivan

    2009-01-01

    Full Text Available We introduce a heuristic method for the single resource constrained project scheduling problem, based on the dynamic programming solution of the knapsack problem. This method schedules projects with one type of resources, in the non-preemptive case: once started an activity is not interrupted and runs to completion. We compare the implementation of this method with well-known heuristic scheduling method, called Minimum Slack First (known also as Gray-Kidd algorithm, as well as with Microsoft Project.

  7. Tuning Parameters in Heuristics by Using Design of Experiments Methods

    Science.gov (United States)

    Arin, Arif; Rabadi, Ghaith; Unal, Resit

    2010-01-01

    With the growing complexity of today's large scale problems, it has become more difficult to find optimal solutions by using exact mathematical methods. The need to find near-optimal solutions in an acceptable time frame requires heuristic approaches. In many cases, however, most heuristics have several parameters that need to be "tuned" before they can reach good results. The problem then turns into "finding best parameter setting" for the heuristics to solve the problems efficiently and timely. One-Factor-At-a-Time (OFAT) approach for parameter tuning neglects the interactions between parameters. Design of Experiments (DOE) tools can be instead employed to tune the parameters more effectively. In this paper, we seek the best parameter setting for a Genetic Algorithm (GA) to solve the single machine total weighted tardiness problem in which n jobs must be scheduled on a single machine without preemption, and the objective is to minimize the total weighted tardiness. Benchmark instances for the problem are available in the literature. To fine tune the GA parameters in the most efficient way, we compare multiple DOE models including 2-level (2k ) full factorial design, orthogonal array design, central composite design, D-optimal design and signal-to-noise (SIN) ratios. In each DOE method, a mathematical model is created using regression analysis, and solved to obtain the best parameter setting. After verification runs using the tuned parameter setting, the preliminary results for optimal solutions of multiple instances were found efficiently.

  8. Heuristics guide cooperative behaviors in public goods game

    Science.gov (United States)

    Wang, Yongjie; Chen, Tong

    2015-12-01

    In public goods game (PGG), player's cooperative behavior is not pure economical rationality, but social preference and prosocial intuition play extremely important roles as well. Social preference and prosocial intuition can be guided by heuristics from one's neighbors in daily life. To better investigate the impacts of heuristics on the evolution of cooperation, four types of agents are introduced into our spatial PGG. Through numerical simulations, results show that the larger percentages of cooperators with independent thought, the easier emergence and maintenance of collective cooperative behaviors. Additionally, we find that differentia heuristic capability has great effect on the equilibrium of PGG. Cooperation can be obviously promoted, when heuristic capability of cooperators with independent thought is stronger than that of defectors with independent thought. Finally, we observe that cooperators with independent thought and defectors with independent thought are favorable for the formation of some high quality clusters, which can resist the invasion between each other. Our work may help us understand more clearly the mechanism of cooperation in real world.

  9. Heuristics for minimizing the maximum within-clusters distance

    Directory of Open Access Journals (Sweden)

    José Augusto Fioruci

    2012-12-01

    Full Text Available The clustering problem consists in finding patterns in a data set in order to divide it into clusters with high within-cluster similarity. This paper presents the study of a problem, here called MMD problem, which aims at finding a clustering with a predefined number of clusters that minimizes the largest within-cluster distance (diameter among all clusters. There are two main objectives in this paper: to propose heuristics for the MMD and to evaluate the suitability of the best proposed heuristic results according to the real classification of some data sets. Regarding the first objective, the results obtained in the experiments indicate a good performance of the best proposed heuristic that outperformed the Complete Linkage algorithm (the most used method from the literature for this problem. Nevertheless, regarding the suitability of the results according to the real classification of the data sets, the proposed heuristic achieved better quality results than C-Means algorithm, but worse than Complete Linkage.

  10. Heuristic Approach for Balancing Shift Schedules

    International Nuclear Information System (INIS)

    Kim, Dae Ho; Yun, Young Su; Lee, Yong Hee

    2005-01-01

    In this paper, a heuristic approach for balancing shift schedules is proposed. For the shift schedules, various constraints which have usually been considered in realworld industry are used, and the objective is to minimize the differences of the workloads in each workgroup. The constraints and objective function are implemented in the proposed heuristic approach. Using a simple instance, the efficiency of the proposed heuristic approach is proved

  11. Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

    Directory of Open Access Journals (Sweden)

    Martin M Gossner

    Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

  12. A single cognitive heuristic process meets the complexity of domain-specific moral heuristics.

    Science.gov (United States)

    Dubljević, Veljko; Racine, Eric

    2014-10-01

    The inherence heuristic (a) offers modest insights into the complex nature of both the is-ought tension in moral reasoning and moral reasoning per se, and (b) does not reflect the complexity of domain-specific moral heuristics. Formal and general in nature, we contextualize the process described as "inherence heuristic" in a web of domain-specific heuristics (e.g., agent specific; action specific; consequences specific).

  13. In vitro cell quality of buffy coat platelets in additive solution treated with pathogen reduction technology

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Bochsen, Louise; Salado-Jimena, José A

    2010-01-01

    Pathogen reduction technologies (PRTs) may induce storage lesion in platelet (PLT) concentrates. To investigate this, buffy coat PLTs (BCPs) in PLT additive solution (AS; SSP+) with or without Mirasol PRT (CaridianBCT Biotechnologies) were assessed by quality control tests and four-color flow...

  14. Nuclear fuel technology - Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

    International Nuclear Information System (INIS)

    2003-01-01

    This International Standard specifies a precise and accurate gravimetric method for determining the mass fraction of uranium in uranyl nitrate solutions of nuclear grade quality containing more than 100 g/kg of uranium. Non-volatile impurities influence the accuracy of the method

  15. Cognitive biases and heuristics in medical decision making: a critical review using a systematic search strategy.

    Science.gov (United States)

    Blumenthal-Barby, J S; Krieger, Heather

    2015-05-01

    The role of cognitive biases and heuristics in medical decision making is of growing interest. The purpose of this study was to determine whether studies on cognitive biases and heuristics in medical decision making are based on actual or hypothetical decisions and are conducted with populations that are representative of those who typically make the medical decision; to categorize the types of cognitive biases and heuristics found and whether they are found in patients or in medical personnel; and to critically review the studies based on standard methodological quality criteria. Data sources were original, peer-reviewed, empirical studies on cognitive biases and heuristics in medical decision making found in Ovid Medline, PsycINFO, and the CINAHL databases published in 1980-2013. Predefined exclusion criteria were used to identify 213 studies. During data extraction, information was collected on type of bias or heuristic studied, respondent population, decision type, study type (actual or hypothetical), study method, and study conclusion. Of the 213 studies analyzed, 164 (77%) were based on hypothetical vignettes, and 175 (82%) were conducted with representative populations. Nineteen types of cognitive biases and heuristics were found. Only 34% of studies (n = 73) investigated medical personnel, and 68% (n = 145) confirmed the presence of a bias or heuristic. Each methodological quality criterion was satisfied by more than 50% of the studies, except for sample size and validated instruments/questions. Limitations are that existing terms were used to inform search terms, and study inclusion criteria focused strictly on decision making. Most of the studies on biases and heuristics in medical decision making are based on hypothetical vignettes, raising concerns about applicability of these findings to actual decision making. Biases and heuristics have been underinvestigated in medical personnel compared with patients. © The Author(s) 2014.

  16. Quality risk management during pharmaceutical ‘good distribution practices’ – A plausible solution

    Directory of Open Access Journals (Sweden)

    Nirmal Kumar

    2018-06-01

    Full Text Available Quality of medicinal product is an important facet throughout lifecycle owing to its importance as acceptance criteria at customer’s end. Drugs regulatory agencies have issued guidelines for quality risk evaluation, mitigation and review management. Quality risk management has become an integral part of quality management system at manufacturing plants. Procedures for deviation control, change control, investigations of market complaints and batch failures are dealt with the principle of quality risk management at the manufacturing facility. The exploratory study shows a dearth of research on quality risk management during supply chain operation, however, a few study has been carried out by keeping financial risk into account. This study addresses the gap in literature on quality risk management during supply chain operations. There are cases of unresolved customer complaints and batch failures originated due to inadequacies during distribution of pharmaceutical products. In absence of established quality risk management system during product shipment, there is no effective preventive plan related to risk factors. A corollary of manufacturing quality risk management has been drawn to the distribution of pharmaceutical products through this study. The quality risk management during pharmaceutical distribution may be useful to avoid market complaints, drug recalls, and regulatory actions. This study produces one unique model solution for industry professionals and policymakers opening a scope to reduce the product rejection thereby paving the way for substantial business growth.

  17. Social biases determine spatiotemporal sparseness of ciliate mating heuristics.

    Science.gov (United States)

    Clark, Kevin B

    2012-01-01

    Ciliates become highly social, even displaying animal-like qualities, in the joint presence of aroused conspecifics and nonself mating pheromones. Pheromone detection putatively helps trigger instinctual and learned courtship and dominance displays from which social judgments are made about the availability, compatibility, and fitness representativeness or likelihood of prospective mates and rivals. In earlier studies, I demonstrated the heterotrich Spirostomum ambiguum improves mating competence by effecting preconjugal strategies and inferences in mock social trials via behavioral heuristics built from Hebbian-like associative learning. Heuristics embody serial patterns of socially relevant action that evolve into ordered, topologically invariant computational networks supporting intra- and intermate selection. S. ambiguum employs heuristics to acquire, store, plan, compare, modify, select, and execute sets of mating propaganda. One major adaptive constraint over formation and use of heuristics involves a ciliate's initial subjective bias, responsiveness, or preparedness, as defined by Stevens' Law of subjective stimulus intensity, for perceiving the meaningfulness of mechanical pressures accompanying cell-cell contacts and additional perimating events. This bias controls durations and valences of nonassociative learning, search rates for appropriate mating strategies, potential net reproductive payoffs, levels of social honesty and deception, successful error diagnosis and correction of mating signals, use of insight or analysis to solve mating dilemmas, bioenergetics expenditures, and governance of mating decisions by classical or quantum statistical mechanics. I now report this same social bias also differentially affects the spatiotemporal sparseness, as measured with metric entropy, of ciliate heuristics. Sparseness plays an important role in neural systems through optimizing the specificity, efficiency, and capacity of memory representations. The present

  18. Social biases determine spatiotemporal sparseness of ciliate mating heuristics

    Science.gov (United States)

    2012-01-01

    Ciliates become highly social, even displaying animal-like qualities, in the joint presence of aroused conspecifics and nonself mating pheromones. Pheromone detection putatively helps trigger instinctual and learned courtship and dominance displays from which social judgments are made about the availability, compatibility, and fitness representativeness or likelihood of prospective mates and rivals. In earlier studies, I demonstrated the heterotrich Spirostomum ambiguum improves mating competence by effecting preconjugal strategies and inferences in mock social trials via behavioral heuristics built from Hebbian-like associative learning. Heuristics embody serial patterns of socially relevant action that evolve into ordered, topologically invariant computational networks supporting intra- and intermate selection. S. ambiguum employs heuristics to acquire, store, plan, compare, modify, select, and execute sets of mating propaganda. One major adaptive constraint over formation and use of heuristics involves a ciliate’s initial subjective bias, responsiveness, or preparedness, as defined by Stevens’ Law of subjective stimulus intensity, for perceiving the meaningfulness of mechanical pressures accompanying cell-cell contacts and additional perimating events. This bias controls durations and valences of nonassociative learning, search rates for appropriate mating strategies, potential net reproductive payoffs, levels of social honesty and deception, successful error diagnosis and correction of mating signals, use of insight or analysis to solve mating dilemmas, bioenergetics expenditures, and governance of mating decisions by classical or quantum statistical mechanics. I now report this same social bias also differentially affects the spatiotemporal sparseness, as measured with metric entropy, of ciliate heuristics. Sparseness plays an important role in neural systems through optimizing the specificity, efficiency, and capacity of memory representations. The

  19. Conspicuous Waste and Representativeness Heuristic

    Directory of Open Access Journals (Sweden)

    Tatiana M. Shishkina

    2017-12-01

    Full Text Available The article deals with the similarities between conspicuous waste and representativeness heuristic. The conspicuous waste is analyzed according to the classic Veblen’ interpretation as a strategy to increase social status through conspicuous consumption and conspicuous leisure. In “The Theory of the Leisure Class” Veblen introduced two different types of utility – conspicuous and functional. The article focuses on the possible benefits of the analysis of conspicuous utility not only in terms of institutional economic theory, but also in terms of behavioral economics. To this end, the representativeness heuristics is considered, on the one hand, as a way to optimize the decision-making process, which allows to examine it in comparison with procedural rationality by Simon. On the other hand, it is also analyzed as cognitive bias within the Kahneman and Twersky’ approach. The article provides the analysis of the patterns in the deviations from the rational behavior strategy that could be observed in case of conspicuous waste both in modern market economies in the form of conspicuous consumption and in archaic economies in the form of gift-exchange. The article also focuses on the marketing strategies for luxury consumption’ advertisement. It highlights the impact of the symbolic capital (in Bourdieu’ interpretation on the social and symbolic payments that actors get from the act of conspicuous waste. This allows to perform a analysis of conspicuous consumption both as a rational way to get the particular kind of payments, and, at the same time, as a form of institutionalized cognitive bias.

  20. Visualization for Hyper-Heuristics: Back-End Processing

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Luke [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Modern society is faced with increasingly complex problems, many of which can be formulated as generate-and-test optimization problems. Yet, general-purpose optimization algorithms may sometimes require too much computational time. In these instances, hyperheuristics may be used. Hyper-heuristics automate the design of algorithms to create a custom algorithm for a particular scenario, finding the solution significantly faster than its predecessor. However, it may be difficult to understand exactly how a design was derived and why it should be trusted. This project aims to address these issues by creating an easy-to-use graphical user interface (GUI) for hyper-heuristics and an easy-to-understand scientific visualization for the produced solutions. To support the development of this GUI, my portion of the research involved developing algorithms that would allow for parsing of the data produced by the hyper-heuristics. This data would then be sent to the front-end, where it would be displayed to the end user.

  1. The Probability Heuristics Model of Syllogistic Reasoning.

    Science.gov (United States)

    Chater, Nick; Oaksford, Mike

    1999-01-01

    Proposes a probability heuristic model for syllogistic reasoning and confirms the rationality of this heuristic by an analysis of the probabilistic validity of syllogistic reasoning that treats logical inference as a limiting case of probabilistic inference. Meta-analysis and two experiments involving 40 adult participants and using generalized…

  2. Modeling reproductive decisions with simple heuristics

    Directory of Open Access Journals (Sweden)

    Peter Todd

    2013-10-01

    Full Text Available BACKGROUND Many of the reproductive decisions that humans make happen without much planning or forethought, arising instead through the use of simple choice rules or heuristics that involve relatively little information and processing. Nonetheless, these heuristic-guided decisions are typically beneficial, owing to humans' ecological rationality - the evolved fit between our constrained decision mechanisms and the adaptive problems we face. OBJECTIVE This paper reviews research on the ecological rationality of human decision making in the domain of reproduction, showing how fertility-related decisions are commonly made using various simple heuristics matched to the structure of the environment in which they are applied, rather than being made with information-hungry mechanisms based on optimization or rational economic choice. METHODS First, heuristics for sequential mate search are covered; these heuristics determine when to stop the process of mate search by deciding that a good-enough mate who is also mutually interested has been found, using a process of aspiration-level setting and assessing. These models are tested via computer simulation and comparison to demographic age-at-first-marriage data. Next, a heuristic process of feature-based mate comparison and choice is discussed, in which mate choices are determined by a simple process of feature-matching with relaxing standards over time. Parental investment heuristics used to divide resources among offspring are summarized. Finally, methods for testing the use of such mate choice heuristics in a specific population over time are then described.

  3. Cooperative heuristic multi-agent planning

    NARCIS (Netherlands)

    De Weerdt, M.M.; Tonino, J.F.M.; Witteveen, C.

    2001-01-01

    In this paper we will use the framework to study cooperative heuristic multi-agent planning. During the construction of their plans, the agents use a heuristic function inspired by the FF planner (l3l). At any time in the process of planning the agents may exchange available resources, or they may

  4. "A Heuristic for Visual Thinking in History"

    Science.gov (United States)

    Staley, David J.

    2007-01-01

    This article details a heuristic history teachers can use in assigning and evaluating multimedia projects in history. To use this heuristic successfully, requires more than simply following the steps in the list or stages in a recipe: in many ways, it requires a reorientation in what it means to think like an historian. This article, as much as…

  5. Effective Heuristics for New Venture Formation

    NARCIS (Netherlands)

    Kraaijenbrink, Jeroen

    2010-01-01

    Entrepreneurs are often under time pressure and may only have a short window of opportunity to launch their new venture. This means they often have no time for rational analytical decisions and rather rely on heuristics. Past research on entrepreneurial heuristics has primarily focused on predictive

  6. Religion, Heuristics, and Intergenerational Risk Management

    OpenAIRE

    Rupert Read; Nassim Nicholas Taleb

    2014-01-01

    Religions come with risk-​managing interdicts and heuristics, and they carry such interdicts and heuristics across generations. We remark on such facets of religion in relation to a propensity among some decision scientists and others to regard practices that they cannot understand as being irrational, biased, and so on.

  7. A novel heuristic algorithm for capacitated vehicle routing problem

    Science.gov (United States)

    Kır, Sena; Yazgan, Harun Reşit; Tüncel, Emre

    2017-09-01

    The vehicle routing problem with the capacity constraints was considered in this paper. It is quite difficult to achieve an optimal solution with traditional optimization methods by reason of the high computational complexity for large-scale problems. Consequently, new heuristic or metaheuristic approaches have been developed to solve this problem. In this paper, we constructed a new heuristic algorithm based on the tabu search and adaptive large neighborhood search (ALNS) with several specifically designed operators and features to solve the capacitated vehicle routing problem (CVRP). The effectiveness of the proposed algorithm was illustrated on the benchmark problems. The algorithm provides a better performance on large-scaled instances and gained advantage in terms of CPU time. In addition, we solved a real-life CVRP using the proposed algorithm and found the encouraging results by comparison with the current situation that the company is in.

  8. An Efficient Heuristic Approach for Irregular Cutting Stock Problem in Ship Building Industry

    Directory of Open Access Journals (Sweden)

    Yan-xin Xu

    2016-01-01

    Full Text Available This paper presents an efficient approach for solving a real two-dimensional irregular cutting stock problem in ship building industry. Cutting stock problem is a common cutting and packing problem that arises in a variety of industrial applications. A modification of selection heuristic Exact Fit is applied in our research. In the case referring to irregular shapes, a placement heuristics is more important to construct a complete solution. A placement heuristic relating to bottom-left-fill is presented. We evaluate the proposed approach using generated instance only with convex shapes in literatures and some instances with nonconvex shapes based on real problem from ship building industry. The results demonstrate that the effectiveness and efficiency of the proposed approach are significantly better than some conventional heuristics.

  9. Defining Usability Heuristics for Adoption and Efficiency of an Electronic Workflow Document Management System

    Science.gov (United States)

    Fuentes, Steven

    2017-01-01

    Usability heuristics have been established for different uses and applications as general guidelines for user interfaces. These can affect the implementation of industry solutions and play a significant role regarding cost reduction and process efficiency. The area of electronic workflow document management (EWDM) solutions, also known as…

  10. Isolation of high quality graphene from Ru by solution phase intercalation

    Science.gov (United States)

    Koren, E.; Sutter, E.; Bliznakov, S.; Ivars-Barcelo, F.; Sutter, P.

    2013-09-01

    We introduce a method for isolating graphene grown on epitaxial Ru(0001)/α-Al2O3. The strong graphene/Ru(0001) coupling is weakened by electrochemically driven intercalation of hydrogen underpotentially deposited in aqueous KOH solution, which allows the penetration of water molecules at the graphene/Ru(0001) interface. Following these electrochemically driven processes, the graphene can be isolated by electrochemical hydrogen evolution and transferred to arbitrary supports. Raman and transport measurements demonstrate the high quality of the transferred graphene. Our results show that intercalation, typically carried out in vacuum, can be extended to solution environments for graphene processing under ambient conditions.

  11. Heuristics and representational change in two-move matchstick arithmetic tasks

    Directory of Open Access Journals (Sweden)

    Michael Öllinger

    2006-01-01

    Full Text Available Insight problems are problems where the problem solver struggles to find a solution until * aha! * the solution suddenly appears. Two contemporary theories suggest that insight problems are difficult either because problem solvers begin with an incorrect representation of the problem, or that problem solvers apply inappropriate heuristics to the problem. The relative contributions of representational change and inappropriate heuristics on the process of insight problem solving was studied with a task that required the problem solver to move two matchsticks in order to transform an incorrect arithmetic statement into a correct one. Problem solvers (N = 120 worked on two different types of two-move matchstick arithmetic problems that both varied with respect to the effectiveness of heuristics and to the degree of a necessary representational change of the problem representation. A strong influence of representational change on solution rates was found whereas the influence of heuristics hadminimal effects on solution rates. That is, the difficulty of insight problems within the two-move matchstick arithmetic domain is governed by the degree of representational change required. A model is presented that details representational change as the necessary condition for ensuring that appropriate heuristics can be applied on the proper problem representation.

  12. Heuristic Strategies in Systems Biology

    Directory of Open Access Journals (Sweden)

    Fridolin Gross

    2016-06-01

    Full Text Available Systems biology is sometimes presented as providing a superior approach to the problem of biological complexity. Its use of ‘unbiased’ methods and formal quantitative tools might lead to the impression that the human factor is effectively eliminated. However, a closer look reveals that this impression is misguided. Systems biologists cannot simply assemble molecular information and compute biological behavior. Instead, systems biology’s main contribution is to accelerate the discovery of mechanisms by applying models as heuristic tools. These models rely on a variety of idealizing and simplifying assumptions in order to be efficient for this purpose. The strategies of systems biologists are similar to those of experimentalists in that they attempt to reduce the complexity of the discovery process. Analyzing and comparing these strategies, or ‘heuristics’, reveals the importance of the human factor in computational approaches and helps to situate systems biology within the epistemic landscape of the life sciences.

  13. Heuristic approach to train rescheduling

    Directory of Open Access Journals (Sweden)

    Mladenović Snežana

    2007-01-01

    Full Text Available Starting from the defined network topology and the timetable assigned beforehand, the paper considers a train rescheduling in respond to disturbances that have occurred. Assuming that the train trips are jobs, which require the elements of infrastructure - resources, it was done by the mapping of the initial problem into a special case of job shop scheduling problem. In order to solve the given problem, a constraint programming approach has been used. A support to fast finding "enough good" schedules is offered by original separation, bound and search heuristic algorithms. In addition, to improve the time performance, instead of the actual objective function with a large domain, a surrogate objective function is used with a smaller domain, if there is such. .

  14. Proportional reasoning as a heuristic-based process: time constraint and dual task considerations.

    Science.gov (United States)

    Gillard, Ellen; Van Dooren, Wim; Schaeken, Walter; Verschaffel, Lieven

    2009-01-01

    The present study interprets the overuse of proportional solution methods from a dual process framework. Dual process theories claim that analytic operations involve time-consuming executive processing, whereas heuristic operations are fast and automatic. In two experiments to test whether proportional reasoning is heuristic-based, the participants solved "proportional" problems, for which proportional solution methods provide correct answers, and "nonproportional" problems known to elicit incorrect answers based on the assumption of proportionality. In Experiment 1, the available solution time was restricted. In Experiment 2, the executive resources were burdened with a secondary task. Both manipulations induced an increase in proportional answers and a decrease in correct answers to nonproportional problems. These results support the hypothesis that the choice for proportional methods is heuristic-based.

  15. THE HEURISTIC FUNCTION OF SPORT

    Directory of Open Access Journals (Sweden)

    Adam Petrović

    2012-09-01

    Full Text Available Being a significant area of human activity, sport has multiple functions. One of the more important functions of sport, especially top sport, is the inventive heuristic function. Creative work, being a process of creating new values, represents a significant possibility for advancement of sport. This paper aims at pointing at the various dimensions of human creative work, at the creative work which can be seen in sport (in a narrow sense and at the scientific and practical areas which borderline sport. The method of theoretical analysis of different approaches to the phenomenon of creative work , both in general and in sport, was applied in this paper. This area can be systematized according to various criterion : the level of creative work, different fields where it appears, the subjects of creative work - creators etc. Case analysis shows that the field of creative work in sport is widening and deepening constantly. There are different levels of creativity not only in the system of training and competition, but in a wider social context of sport as well. As a process of human spirit and mind the creative work belongs not just to athletes and coaches, but also to all the people and social groups who's creative power manifests itself in sport. The classification of creative work in sport according to various criterion allows for heuristic function of sport to be explained comprehensively and to create an image how do the sparks of human spirit improve the micro cosmos of sport. A thorough classification of creative work in sport allows for a detailed analysis of all the elements of creative work and each of it’s area in sport. In this way the progress in sport , as a consequence of innovations in both competitions and athletes’ training and of everything that goes with those activities, can be guided into the needed direction more easily as well as studied and applied.

  16. A Comparison of Heuristics with Modularity Maximization Objective using Biological Data Sets

    Directory of Open Access Journals (Sweden)

    Pirim Harun

    2016-01-01

    Full Text Available Finding groups of objects exhibiting similar patterns is an important data analytics task. Many disciplines have their own terminologies such as cluster, group, clique, community etc. defining the similar objects in a set. Adopting the term community, many exact and heuristic algorithms are developed to find the communities of interest in available data sets. Here, three heuristic algorithms to find communities are compared using five gene expression data sets. The heuristics have a common objective function of maximizing the modularity that is a quality measure of a partition and a reflection of objects’ relevance in communities. Partitions generated by the heuristics are compared with the real ones using the adjusted rand index, one of the most commonly used external validation measures. The paper discusses the results of the partitions on the mentioned biological data sets.

  17. Optimization of pressurized water reactor shuffling by simulated annealing with heuristics

    International Nuclear Information System (INIS)

    Stevens, J.G.; Smith, K.S.; Rempe, K.R.; Downar, T.J.

    1995-01-01

    Simulated-annealing optimization of reactor core loading patterns is implemented with support for design heuristics during candidate pattern generation. The SIMAN optimization module uses the advanced nodal method of SIMULATE-3 and the full cross-section detail of CASMO-3 to evaluate accurately the neutronic performance of each candidate, resulting in high-quality patterns. The use of heuristics within simulated annealing is explored. Heuristics improve the consistency of optimization results for both fast- and slow-annealing runs with no penalty from the exclusion of unusual candidates. Thus, the heuristic application of designer judgment during automated pattern generation is shown to be effective. The capability of the SIMAN module to find and evaluate families of loading patterns that satisfy design constraints and have good objective performance within practical run times is demonstrated. The use of automated evaluations of successive cycles to explore multicycle effects of design decisions is discussed

  18. Application of Heuristic and Metaheuristic Algorithms in Solving Constrained Weber Problem with Feasible Region Bounded by Arcs

    Directory of Open Access Journals (Sweden)

    Igor Stojanović

    2017-01-01

    Full Text Available The continuous planar facility location problem with the connected region of feasible solutions bounded by arcs is a particular case of the constrained Weber problem. This problem is a continuous optimization problem which has a nonconvex feasible set of constraints. This paper suggests appropriate modifications of four metaheuristic algorithms which are defined with the aim of solving this type of nonconvex optimization problems. Also, a comparison of these algorithms to each other as well as to the heuristic algorithm is presented. The artificial bee colony algorithm, firefly algorithm, and their recently proposed improved versions for constrained optimization are appropriately modified and applied to the case study. The heuristic algorithm based on modified Weiszfeld procedure is also implemented for the purpose of comparison with the metaheuristic approaches. Obtained numerical results show that metaheuristic algorithms can be successfully applied to solve the instances of this problem of up to 500 constraints. Among these four algorithms, the improved version of artificial bee algorithm is the most efficient with respect to the quality of the solution, robustness, and the computational efficiency.

  19. Storage Solutions for Power Quality Problems in Cyprus Electricity Distribution Network

    Directory of Open Access Journals (Sweden)

    Andreas Poullikkas

    2014-01-01

    Full Text Available In this work, a prediction of the effects of introducing energy storage systems on the network stability of the distribution network of Cyprus and a comparison in terms of cost with a traditional solution is carried out. In particular, for solving possible overvoltage problems, several scenarios of storage units' installation are used and compared with the alternative solution of extra cable connection between the node with the lowest voltage and the node with the highest voltage of the distribution network. For the comparison, a case study of a typical LV distribution feeder in the power system of Cyprus is used. The results indicated that the performance indicator of each solution depends on the type, the size and the position of installation of the storage unit. Also, as more storage units are installed the better the performance indicator and the more attractive is the investment in storage units to solve power quality problems in the distribution network. In the case where the technical requirements in voltage limitations according to distribution regulations are satisfied with one storage unit, the installation of an additional storage unit will only increase the final cost. The best solution, however, still remains the alternative solution of extra cable connection between the node with the lowest voltage and the node with the highest voltage of the distribution network, due to the lower investment costs compared to that of the storage units.

  20. 75 FR 82010 - AceInfo Solutions and Avaya Government Solutions, Koansys LLC, and Quality Associates Inc...

    Science.gov (United States)

    2010-12-29

    ... Associates Inc., to fulfill the obligations of the contract. DATES: AceInfo Solutions and its subcontractors... Inc. have been awarded a contract to perform work for OPP, and access to this information will enable... Contract No. GS-06F-0337Z, AceInfo Solutions and its subcontractors, Avaya Government Solutions, Koansys...

  1. The Effect of Incentive Structure on Heuristic Decision Making: The Proportion Heuristic

    OpenAIRE

    Robert Oxoby

    2007-01-01

    When making judgments, individuals often utilize heuristics to interpret information. We report on a series of experiments designed to test the ways in which incentive mechanisms influence the use of a particular heuristic in decision-making. Specifically, we demonstrate how information regarding the number of available practice problems influences the behaviors of individuals preparing for an exam (the proportion heuristic). More importantly the extent to which this information influences be...

  2. Solution standards for quality control of nuclear-material analytical measurements

    International Nuclear Information System (INIS)

    Clark, J.P.

    1981-01-01

    Analytical chemistry measurement control depends upon reliable solution standards. At the Savannah River Plant Control Laboratory over a thousand analytical measurements are made daily for process control, product specification, accountability, and nuclear safety. Large quantities of solution standards are required for a measurement quality control program covering the many different analytical chemistry methods. Savannah River Plant produced uranium, plutonium, neptunium, and americium metals or oxides are dissolved to prepare stock solutions for working or Quality Control Standards (QCS). Because extensive analytical effort is required to characterize or confirm these solutions, they are prepared in large quantities. These stock solutions are diluted and blended with different chemicals and/or each other to synthesize QCS that match the matrices of different process streams. The target uncertainty of a standard's reference value is 10% of the limit of error of the methods used for routine measurements. Standard Reference Materials from NBS are used according to special procedures to calibrate the methods used in measuring the uranium and plutonium standards so traceability can be established. Special precautions are required to minimize the effects of temperature, radiolysis, and evaporation. Standard reference values are periodically corrected to eliminate systematic errors caused by evaporation or decay products. Measurement control is achieved by requiring analysts to analyze a blind QCS each shift a measurement system is used on plant samples. Computer evaluation determines whether or not a measurement is within the +- 3 sigma control limits. Monthly evaluations of the QCS measurements are made to determine current bias correction factors for accountability measurements and detect significant changes in the bias and precision statistics. The evaluations are also used to plan activities for improving the reliability of the analytical chemistry measurements

  3. Heuristic attacks against graphical password generators

    CSIR Research Space (South Africa)

    Peach, S

    2010-05-01

    Full Text Available In this paper the authors explore heuristic attacks against graphical password generators. A new trend is emerging to use user clickable pictures to generate passwords. This technique of authentication can be successfully used for - for example...

  4. A Direct Heuristic Algorithm for Linear Programming

    Indian Academy of Sciences (India)

    Abstract. An (3) mathematically non-iterative heuristic procedure that needs no artificial variable is presented for solving linear programming problems. An optimality test is included. Numerical experiments depict the utility/scope of such a procedure.

  5. RELAXATION HEURISTICS FOR THE SET COVERING PROBLEM

    OpenAIRE

    Umetani, Shunji; Yagiura, Mutsunori; 柳浦, 睦憲

    2007-01-01

    The set covering problem (SCP) is one of representative combinatorial optimization problems, which has many practical applications. The continuous development of mathematical programming has derived a number of impressive heuristic algorithms as well as exact branch-and-bound algorithms, which can solve huge SCP instances of bus, railway and airline crew scheduling problems. We survey heuristic algorithms for SCP focusing mainly on contributions of mathematical programming techniques to heuri...

  6. A heuristic forecasting model for stock decision

    OpenAIRE

    Zhang, D.; Jiang, Q.; Li, X.

    2005-01-01

    This paper describes a heuristic forecasting model based on neural networks for stock decision-making. Some heuristic strategies are presented for enhancing the learning capability of neural networks and obtaining better trading performance. The China Shanghai Composite Index is used as case study. The forecasting model can forecast the buying and selling signs according to the result of neural network prediction. Results are compared with a benchmark buy-and-hold strategy. ...

  7. Psychology into economics: fast and frugal heuristics

    OpenAIRE

    Schilirò, Daniele

    2015-01-01

    The present essay focuses on the fast and frugal heuristics program set forth by Gerd Gigerenzer and his fellows. In particular it examines the contribution of Gigerenzer and Goldstein (1996) ‘Reasoning the Fast and Frugal Way: Models of Bounded Rationality’. This essay, following the theoretical propositions and the empirical evidence of Gigerenzer and Goldstein, points out that simple cognitive mechanisms such as fast and frugal heuristics can be capable of successful performance in real wo...

  8. Arational heuristic model of economic decision making

    OpenAIRE

    Grandori, Anna

    2010-01-01

    The article discuss the limits of both the rational actor and the behavioral paradigms in explaining and guiding innovative decision making and outlines a model of economic decision making that in the course of being 'heuristic' (research and discovery oriented) is also 'rational' (in the broad sense of following correct reasoning and scientific methods, non 'biasing'). The model specifies a set of 'rational heuristics' for innovative decision making, for the various sub-processes of problem ...

  9. Social heuristics shape intuitive cooperation.

    Science.gov (United States)

    Rand, David G; Peysakhovich, Alexander; Kraft-Todd, Gordon T; Newman, George E; Wurzbacher, Owen; Nowak, Martin A; Greene, Joshua D

    2014-04-22

    Cooperation is central to human societies. Yet relatively little is known about the cognitive underpinnings of cooperative decision making. Does cooperation require deliberate self-restraint? Or is spontaneous prosociality reined in by calculating self-interest? Here we present a theory of why (and for whom) intuition favors cooperation: cooperation is typically advantageous in everyday life, leading to the formation of generalized cooperative intuitions. Deliberation, by contrast, adjusts behaviour towards the optimum for a given situation. Thus, in one-shot anonymous interactions where selfishness is optimal, intuitive responses tend to be more cooperative than deliberative responses. We test this 'social heuristics hypothesis' by aggregating across every cooperation experiment using time pressure that we conducted over a 2-year period (15 studies and 6,910 decisions), as well as performing a novel time pressure experiment. Doing so demonstrates a positive average effect of time pressure on cooperation. We also find substantial variation in this effect, and show that this variation is partly explained by previous experience with one-shot lab experiments.

  10. Data Quality Control: Challenges, Methods, and Solutions from an Eco-Hydrologic Instrumentation Network

    Science.gov (United States)

    Eiriksson, D.; Jones, A. S.; Horsburgh, J. S.; Cox, C.; Dastrup, D.

    2017-12-01

    Over the past few decades, advances in electronic dataloggers and in situ sensor technology have revolutionized our ability to monitor air, soil, and water to address questions in the environmental sciences. The increased spatial and temporal resolution of in situ data is alluring. However, an often overlooked aspect of these advances are the challenges data managers and technicians face in performing quality control on millions of data points collected every year. While there is general agreement that high quantities of data offer little value unless the data are of high quality, it is commonly understood that despite efforts toward quality assurance, environmental data collection occasionally goes wrong. After identifying erroneous data, data managers and technicians must determine whether to flag, delete, leave unaltered, or retroactively correct suspect data. While individual instrumentation networks often develop their own QA/QC procedures, there is a scarcity of consensus and literature regarding specific solutions and methods for correcting data. This may be because back correction efforts are time consuming, so suspect data are often simply abandoned. Correction techniques are also rarely reported in the literature, likely because corrections are often performed by technicians rather than the researchers who write the scientific papers. Details of correction procedures are often glossed over as a minor component of data collection and processing. To help address this disconnect, we present case studies of quality control challenges, solutions, and lessons learned from a large scale, multi-watershed environmental observatory in Northern Utah that monitors Gradients Along Mountain to Urban Transitions (GAMUT). The GAMUT network consists of over 40 individual climate, water quality, and storm drain monitoring stations that have collected more than 200 million unique data points in four years of operation. In all of our examples, we emphasize that scientists

  11. Heuristic thinking makes a chemist smart.

    Science.gov (United States)

    Graulich, Nicole; Hopf, Henning; Schreiner, Peter R

    2010-05-01

    We focus on the virtually neglected use of heuristic principles in understanding and teaching of organic chemistry. As human thinking is not comparable to computer systems employing factual knowledge and algorithms--people rarely make decisions through careful considerations of every possible event and its probability, risks or usefulness--research in science and teaching must include psychological aspects of the human decision making processes. Intuitive analogical and associative reasoning and the ability to categorize unexpected findings typically demonstrated by experienced chemists should be made accessible to young learners through heuristic concepts. The psychology of cognition defines heuristics as strategies that guide human problem-solving and deciding procedures, for example with patterns, analogies, or prototypes. Since research in the field of artificial intelligence and current studies in the psychology of cognition have provided evidence for the usefulness of heuristics in discovery, the status of heuristics has grown into something useful and teachable. In this tutorial review, we present a heuristic analysis of a familiar fundamental process in organic chemistry--the cyclic six-electron case, and we show that this approach leads to a more conceptual insight in understanding, as well as in teaching and learning.

  12. Heuristics as Bayesian inference under extreme priors.

    Science.gov (United States)

    Parpart, Paula; Jones, Matt; Love, Bradley C

    2018-05-01

    Simple heuristics are often regarded as tractable decision strategies because they ignore a great deal of information in the input data. One puzzle is why heuristics can outperform full-information models, such as linear regression, which make full use of the available information. These "less-is-more" effects, in which a relatively simpler model outperforms a more complex model, are prevalent throughout cognitive science, and are frequently argued to demonstrate an inherent advantage of simplifying computation or ignoring information. In contrast, we show at the computational level (where algorithmic restrictions are set aside) that it is never optimal to discard information. Through a formal Bayesian analysis, we prove that popular heuristics, such as tallying and take-the-best, are formally equivalent to Bayesian inference under the limit of infinitely strong priors. Varying the strength of the prior yields a continuum of Bayesian models with the heuristics at one end and ordinary regression at the other. Critically, intermediate models perform better across all our simulations, suggesting that down-weighting information with the appropriate prior is preferable to entirely ignoring it. Rather than because of their simplicity, our analyses suggest heuristics perform well because they implement strong priors that approximate the actual structure of the environment. We end by considering how new heuristics could be derived by infinitely strengthening the priors of other Bayesian models. These formal results have implications for work in psychology, machine learning and economics. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Application of the heuristically based GPT theory to termohydraulic problems

    International Nuclear Information System (INIS)

    Alvim, A.C.M.

    1988-01-01

    Application of heuristically based generalized perturbation theory (GPT) to the thermohydraulic (generally nonlinear) field is here illustrated. After a short description of the general methodology, the (linear) equations governing the importance function relevant to a generic multichannel problem are derived, within the physical model adopted in the COBRA IV-I Code. These equations are put in a form which should benefit of the calculational scheme of the original COBRA Code in the sense that only minor changes of it (mostly implying physical constants and source terms redefinitions) should be necessary for their solutions. (author) [pt

  14. A NEW HEURISTIC ALGORITHM FOR MULTIPLE TRAVELING SALESMAN PROBLEM

    Directory of Open Access Journals (Sweden)

    F. NURIYEVA

    2017-06-01

    Full Text Available The Multiple Traveling Salesman Problem (mTSP is a combinatorial optimization problem in NP-hard class. The mTSP aims to acquire the minimum cost for traveling a given set of cities by assigning each of them to a different salesman in order to create m number of tours. This paper presents a new heuristic algorithm based on the shortest path algorithm to find a solution for the mTSP. The proposed method has been programmed in C language and its performance analysis has been carried out on the library instances. The computational results show the efficiency of this method.

  15. Heuristics for multiobjective multiple sequence alignment.

    Science.gov (United States)

    Abbasi, Maryam; Paquete, Luís; Pereira, Francisco B

    2016-07-15

    Aligning multiple sequences arises in many tasks in Bioinformatics. However, the alignments produced by the current software packages are highly dependent on the parameters setting, such as the relative importance of opening gaps with respect to the increase of similarity. Choosing only one parameter setting may provide an undesirable bias in further steps of the analysis and give too simplistic interpretations. In this work, we reformulate multiple sequence alignment from a multiobjective point of view. The goal is to generate several sequence alignments that represent a trade-off between maximizing the substitution score and minimizing the number of indels/gaps in the sum-of-pairs score function. This trade-off gives to the practitioner further information about the similarity of the sequences, from which she could analyse and choose the most plausible alignment. We introduce several heuristic approaches, based on local search procedures, that compute a set of sequence alignments, which are representative of the trade-off between the two objectives (substitution score and indels). Several algorithm design options are discussed and analysed, with particular emphasis on the influence of the starting alignment and neighborhood search definitions on the overall performance. A perturbation technique is proposed to improve the local search, which provides a wide range of high-quality alignments. The proposed approach is tested experimentally on a wide range of instances. We performed several experiments with sequences obtained from the benchmark database BAliBASE 3.0. To evaluate the quality of the results, we calculate the hypervolume indicator of the set of score vectors returned by the algorithms. The results obtained allow us to identify reasonably good choices of parameters for our approach. Further, we compared our method in terms of correctly aligned pairs ratio and columns correctly aligned ratio with respect to reference alignments. Experimental results show

  16. Quantitative Evaluation of Acetaminophen in Oral Solutions by Dispersive Raman Spectroscopy for Quality Control

    OpenAIRE

    Borio, Viviane G.; Vinha, RubensJr.; Nicolau, Renata A.; de Oliveira, Hueder Paulo M.; de Lima, Carlos J.; Silveira, LandulfoJr.

    2012-01-01

    This work used dispersive Raman spectroscopy to evaluate acetaminophen in commercially available formulations as an analytical methodology for quality control in the pharmaceutical industry. Raman spectra were collected using a near-infrared dispersive Raman spectrometer (830 nm, 50 mW, 20 s exposure time) coupled to a fiber optic probe. Solutions of acetaminophen diluted in excipient (70 to 120% of the commercial concentration of 200 mg/mL) were used to develop a calibration model based on p...

  17. Determination of uranium in uranyl nitrate solutions of nuclear grade quality - Gravimetric method

    International Nuclear Information System (INIS)

    1990-01-01

    This international Standard specifies a precise and accurate gravimetric method for determining the uranium content in uranyl nitrate product solutions of nuclear grade quality at concentrations above 100 g/l of uranium. Non-volatile impurities influence the accuracy of the method. Uranyl nitrate is converted into uranium octoxide (U 3 O 8 ) by ignition in air to constant mass at 900 deg. C ± 10 deg. C. Calculation of the uranium content in the sample using a gravimetric conversion factor which depends on the isotopic composition of the uranium. The isotopic composition is determined by mass spectrometry

  18. PENDEKATAN ACTIVITY-BASED COSTING DAN METODE PENCARIAN HEURISTIC UNTUK MENYELESAIKAN PROBLEM PEMILIHAN PERALATAN PADA FLEXIBLE MANUFACTURING SYSTEMS (FMS

    Directory of Open Access Journals (Sweden)

    Gregorius Satia Budhi

    2002-01-01

    Full Text Available The application of Activity Based Costing (ABC approach to select the set-machine that is used in the production of Flexible Manufacture System (FMS based on technical and economical criteria can be useful for producers to design FMS by considering the minimum production cost. In the other hand, Heuristic Search is known to have a short searching time. Algorithm Heuristic that using ABC approach as the weight in finding the solution to shorten the equipment selection time during the design / redesign process of the FMS in less than exponential time was designed in this research. The increasing speed is useful because with the faster time in design / redesign process, therefore the flexibility level of part variety that can be processed will become better. Theoretical and empirical analysis in Algorithm Heuristic shows that time searching to get appropriate set of equipment is not too long, so that we can assume that the designed Algorithm Heuristic can be implemented in the real world. By comparing the empirical result of Algorithm Heuristic to the Algorithm Exhaustive, we can also assume that Algorithm Heuristic that using ABC method as the weight for finding solution can optimise the equipment selection problem of FMS based on economical criteria too. Abstract in Bahasa Indonesia : Penggunaan pendekatan Activity Based Costing (ABC untuk memilih set mesin yang digunakan dalam produksi pada Flexible Manufacture Systems (FMS berdasar atas kriteria teknis dan ekonomis, dapat membantu pelaku produksi untuk mendisain FMS dengan pertimbangan minimalisasi biaya produksi. Sementara itu, Heuristic Search dikenal memiliki waktu pencarian yang singkat. Pada riset ini didisain sebuah Algoritma Heuristic yang menggunakan pendekatan ABC sebagai bobot dalam pencarian solusi, untuk mempersingkat waktu pemilihan peralatan saat desain/redisain FMS dalam waktu kurang dari waktu Eksponensial. Peningkatan kecepatan ini bermanfaat, karena dengan cepatnya waktu

  19. Optimization of soymilk, mango nectar and sucrose solution mixes for better quality of soymilk based beverage.

    Science.gov (United States)

    Getu, Rahel; Tola, Yetenayet B; Neela, Satheesh

    2017-01-01

    Soy milk-based beverages play an important role as a healthy food alternative for human consumption. However, the ‘beany’ flavor and chalky mouth feel of soy milk often makes it unpalatable to consumers. The objective of the present study is to optimize a blend of soy milk, mango nectar and sucrose solution for the best quality soy milk-based beverage. This study was designed to develop a soy milk blended beverage, with mango nectar and sucrose solutions, with the best physicochemical and sensory properties. Fourteen combinations of formulations were determined by D-optimal mixture simplex lattice design, by using Design expert. The blended beverages were prepared by mixing the three basic ingredients with the range of 60−100% soy milk, 0–25% mango nectar and 0–15% sucrose solution. The prepared blended beverage was analyzed for selected physicochemical and sensory properties. The statistical significance of the terms in the regression equations were examined by Analysis of Variance (ANOVA) for each response and the significance test level was set at 5% (p nectar and sucrose solution increased, total color change, total soluble solid, gross energy, titratable acidity, and beta-carotene contents increased but with a decrease in moisture , ash, protein, ether extract, minerals and phytic acid contents was observed. Fi- nally, numerical optimization determined that 81% soy milk, 16% Mango nectar and 3% sugar solution will give by a soy milk blended beverage with the best physicochemical and sensory properties, with a desirability of 0.564. Blending soy milk with fruit juice such as mango is beneficial, as it improves sensory as well as selected nutritional parameters.

  20. Using tree diversity to compare phylogenetic heuristics.

    Science.gov (United States)

    Sul, Seung-Jin; Matthews, Suzanne; Williams, Tiffani L

    2009-04-29

    Evolutionary trees are family trees that represent the relationships between a group of organisms. Phylogenetic heuristics are used to search stochastically for the best-scoring trees in tree space. Given that better tree scores are believed to be better approximations of the true phylogeny, traditional evaluation techniques have used tree scores to determine the heuristics that find the best scores in the fastest time. We develop new techniques to evaluate phylogenetic heuristics based on both tree scores and topologies to compare Pauprat and Rec-I-DCM3, two popular Maximum Parsimony search algorithms. Our results show that although Pauprat and Rec-I-DCM3 find the trees with the same best scores, topologically these trees are quite different. Furthermore, the Rec-I-DCM3 trees cluster distinctly from the Pauprat trees. In addition to our heatmap visualizations of using parsimony scores and the Robinson-Foulds distance to compare best-scoring trees found by the two heuristics, we also develop entropy-based methods to show the diversity of the trees found. Overall, Pauprat identifies more diverse trees than Rec-I-DCM3. Overall, our work shows that there is value to comparing heuristics beyond the parsimony scores that they find. Pauprat is a slower heuristic than Rec-I-DCM3. However, our work shows that there is tremendous value in using Pauprat to reconstruct trees-especially since it finds identical scoring but topologically distinct trees. Hence, instead of discounting Pauprat, effort should go in improving its implementation. Ultimately, improved performance measures lead to better phylogenetic heuristics and will result in better approximations of the true evolutionary history of the organisms of interest.

  1. Quality check carried out by bricklayers –An E-business solution in a chaotic environment

    DEFF Research Database (Denmark)

    Koch, Christian; Vogelius, Peter

    2006-01-01

    E-business solutions with mobile elements receives increasing attention. The paper evaluates a system within management of quality in architecture, engineering and construction businesses as a test- success which however does not embed in the industry due to a laissez faire type of IT......-governance. This renders a perspective of Demingian quality development supported by E-business solutions and carried out by craftsmen less likely despite a fertile Scandinavian context....

  2. Prediction-based dynamic load-sharing heuristics

    Science.gov (United States)

    Goswami, Kumar K.; Devarakonda, Murthy; Iyer, Ravishankar K.

    1993-01-01

    The authors present dynamic load-sharing heuristics that use predicted resource requirements of processes to manage workloads in a distributed system. A previously developed statistical pattern-recognition method is employed for resource prediction. While nonprediction-based heuristics depend on a rapidly changing system status, the new heuristics depend on slowly changing program resource usage patterns. Furthermore, prediction-based heuristics can be more effective since they use future requirements rather than just the current system state. Four prediction-based heuristics, two centralized and two distributed, are presented. Using trace driven simulations, they are compared against random scheduling and two effective nonprediction based heuristics. Results show that the prediction-based centralized heuristics achieve up to 30 percent better response times than the nonprediction centralized heuristic, and that the prediction-based distributed heuristics achieve up to 50 percent improvements relative to their nonprediction counterpart.

  3. A three-stage heuristic for harvest scheduling with access road network development

    Science.gov (United States)

    Mark M. Clark; Russell D. Meller; Timothy P. McDonald

    2000-01-01

    In this article we present a new model for the scheduling of forest harvesting with spatial and temporal constraints. Our approach is unique in that we incorporate access road network development into the harvest scheduling selection process. Due to the difficulty of solving the problem optimally, we develop a heuristic that consists of a solution construction stage...

  4. The Development of a Culture of Problem Solving with Secondary Students through Heuristic Strategies

    Science.gov (United States)

    Eisenmann, Petr; Novotná, Jarmila; Pribyl, Jirí; Brehovský, Jirí

    2015-01-01

    The article reports the results of a longitudinal research study conducted in three mathematics classes in Czech schools with 62 pupils aged 12-18 years. The pupils were exposed to the use of selected heuristic strategies in mathematical problem solving for a period of 16 months. This was done through solving problems where the solution was the…

  5. Example-Based Learning in Heuristic Domains: A Cognitive Load Theory Account

    Science.gov (United States)

    Renkl, Alexander; Hilbert, Tatjana; Schworm, Silke

    2009-01-01

    One classical instructional effect of cognitive load theory (CLT) is the worked-example effect. Although the vast majority of studies have focused on well-structured and algorithmic sub-domains of mathematics or physics, more recent studies have also analyzed learning with examples from complex domains in which only heuristic solution strategies…

  6. Optimal restoration strategies based on heuristic techniques for electrical distribution networks; Estrategias de restablecimiento optimas basadas en tecnicas heuristicas para redes de distribucion electrica

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Castrejon, J. A; Islas Perez, E; Espinosa Reza, A; Garcia Mendoza, R [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mails: adrian.cruz@iie.org.mx; eislas@iie.org.mx; aer@iie.org.mx; rgarcia@iie.org.mx

    2013-03-15

    In this paper we present a proposed solution to the problem of finding alternatives to reset faults in radial distribution networks power systems. This solution uses a deterministic method based on the definition of heuristics and whose main objectives are to improve execution time and solution quality. This search is based on the alternate repetition of two stages: a stage that attempts to reset the unconnected areas and other areas trying ballasting overloaded. [Spanish] En este articulo se presenta una propuesta de solucion al problema de busqueda de alternativas de restablecimiento para fallas en redes de distribucion radiales en sistemas electricos de potencia. Esta solucion utiliza un metodo deterministico basado en la definicion de heuristicas y cuyos objetivos principales son: mejorar el tiempo de ejecucion y calidad de la solucion. Esta busqueda se basa en la repeticion alternada de dos etapas: una etapa que intenta restablecer las areas desconectadas y otra que intenta deslastrar las areas sobrecargadas.

  7. Relationships between Undergraduates' Argumentation Skills, Conceptual Quality of Problem Solutions, and Problem Solving Strategies in Introductory Physics

    Science.gov (United States)

    Rebello, Carina M.

    2012-01-01

    This study explored the effects of alternative forms of argumentation on undergraduates' physics solutions in introductory calculus-based physics. A two-phase concurrent mixed methods design was employed to investigate relationships between undergraduates' written argumentation abilities, conceptual quality of problem solutions, as well…

  8. Quantifying Heuristic Bias: Anchoring, Availability, and Representativeness.

    Science.gov (United States)

    Richie, Megan; Josephson, S Andrew

    2018-01-01

    Construct: Authors examined whether a new vignette-based instrument could isolate and quantify heuristic bias. Heuristics are cognitive shortcuts that may introduce bias and contribute to error. There is no standardized instrument available to quantify heuristic bias in clinical decision making, limiting future study of educational interventions designed to improve calibration of medical decisions. This study presents validity data to support a vignette-based instrument quantifying bias due to the anchoring, availability, and representativeness heuristics. Participants completed questionnaires requiring assignment of probabilities to potential outcomes of medical and nonmedical scenarios. The instrument randomly presented scenarios in one of two versions: Version A, encouraging heuristic bias, and Version B, worded neutrally. The primary outcome was the difference in probability judgments for Version A versus Version B scenario options. Of 167 participants recruited, 139 enrolled. Participants assigned significantly higher mean probability values to Version A scenario options (M = 9.56, SD = 3.75) than Version B (M = 8.98, SD = 3.76), t(1801) = 3.27, p = .001. This result remained significant analyzing medical scenarios alone (Version A, M = 9.41, SD = 3.92; Version B, M = 8.86, SD = 4.09), t(1204) = 2.36, p = .02. Analyzing medical scenarios by heuristic revealed a significant difference between Version A and B for availability (Version A, M = 6.52, SD = 3.32; Version B, M = 5.52, SD = 3.05), t(404) = 3.04, p = .003, and representativeness (Version A, M = 11.45, SD = 3.12; Version B, M = 10.67, SD = 3.71), t(396) = 2.28, p = .02, but not anchoring. Stratifying by training level, students maintained a significant difference between Version A and B medical scenarios (Version A, M = 9.83, SD = 3.75; Version B, M = 9.00, SD = 3.98), t(465) = 2.29, p = .02, but not residents or attendings. Stratifying by heuristic and training level, availability maintained

  9. Challenges, Solutions, and Quality Metrics of Personal Genome Assembly in Advancing Precision Medicine

    Directory of Open Access Journals (Sweden)

    Wenming Xiao

    2016-04-01

    Full Text Available Even though each of us shares more than 99% of the DNA sequences in our genome, there are millions of sequence codes or structure in small regions that differ between individuals, giving us different characteristics of appearance or responsiveness to medical treatments. Currently, genetic variants in diseased tissues, such as tumors, are uncovered by exploring the differences between the reference genome and the sequences detected in the diseased tissue. However, the public reference genome was derived with the DNA from multiple individuals. As a result of this, the reference genome is incomplete and may misrepresent the sequence variants of the general population. The more reliable solution is to compare sequences of diseased tissue with its own genome sequence derived from tissue in a normal state. As the price to sequence the human genome has dropped dramatically to around $1000, it shows a promising future of documenting the personal genome for every individual. However, de novo assembly of individual genomes at an affordable cost is still challenging. Thus, till now, only a few human genomes have been fully assembled. In this review, we introduce the history of human genome sequencing and the evolution of sequencing platforms, from Sanger sequencing to emerging “third generation sequencing” technologies. We present the currently available de novo assembly and post-assembly software packages for human genome assembly and their requirements for computational infrastructures. We recommend that a combined hybrid assembly with long and short reads would be a promising way to generate good quality human genome assemblies and specify parameters for the quality assessment of assembly outcomes. We provide a perspective view of the benefit of using personal genomes as references and suggestions for obtaining a quality personal genome. Finally, we discuss the usage of the personal genome in aiding vaccine design and development, monitoring host

  10. An LP-based heuristic for the fixed charge transportation problem

    DEFF Research Database (Denmark)

    Klose, Andreas

    2007-01-01

    The fixed charge transportation problem consists in finding a minimum cost network flow from a set of suppliers to a set of customers. Beside costs proportional to quantities transported, transportation costs also include a fixed charge. The paper describes a linear programming based heuristic...... approach for computing lower and upper bounds on the minimal cost. To this end, the LP relaxation is iteratively strengthened by means of adding cuts; in each iteration the current LP solution is then used to guide a local search heuristic. In addition to standard polyhedral cuts as lifted cover...

  11. The effects of Polya's heuristic and diary writing on children's problem solving

    Science.gov (United States)

    Hensberry, Karina K. R.; Jacobbe, Tim

    2012-03-01

    This paper presents the results of a study that aimed at increasing students' problem-solving skills. Polya's (1985) heuristic for problem solving was used and students were required to articulate their thought processes through the use of a structured diary. The diary prompted students to answer questions designed to engage them in the phases of Polya's (1985) heuristic. While it appeared as though most students did not internalise the diary questions, further analysis of students' responses indicated that most students showed improvement in their solution strategies. These results indicate that having students write about their thinking may be beneficial for developing their problem-solving skills.

  12. An Innovative Heuristic in Multi-Item Replenishment Problem for One Warehouse and N Retailers

    Directory of Open Access Journals (Sweden)

    Yugowati Praharsi

    2014-01-01

    Full Text Available Joint replenishment problem (JRP is a type of inventory model which aims to minimize the total inventory cost consisting of major ordering cost, minor ordering cost and inventory holding cost. Different from previous papers, this study considers one warehouse, multi items and N retailers. An innovative heuristic approach is developed to solve the problem. In this paper, we consider a multi echelon inventory system and seek to find a balance between the order cost and the inventory holding costs at each installation. The computational results show that the innovative heuristic provides a near exact optimal solution, but is more efficient in terms of the computational time and the iteration number.

  13. Can we trust module-respect heuristics?

    International Nuclear Information System (INIS)

    Mo, Yuchang

    2013-01-01

    BDD (Binary Decision Diagrams) have proven to be a very efficient tool to assess Fault Trees. However, the size of BDD, and therefore the efficiency of the whole methodology, depends dramatically on the choice of variable ordering. The determination of the best variable ordering is intractable. Therefore, heuristics have been designed to select reasonably good variable orderings. One very important common feature for good static heuristics is to respect modules. In this paper, the notion of module-respect is studied in a systematic way. It is proved that under certain condition there always exists an optimal ordering that respects modules. This condition is that for each module there is always a smallest module BDD and each included module variable appears only once. On the other hand, it is shown that for the trees not satisfying the above sufficient condition the optimal orderings may not be able to be directly generated using module-respect heuristics, even when the shuffling strategy is used.

  14. Judgment under Uncertainty: Heuristics and Biases.

    Science.gov (United States)

    Tversky, A; Kahneman, D

    1974-09-27

    This article described three heuristics that are employed in making judgements under uncertainty: (i) representativeness, which is usually employed when people are asked to judge the probability that an object or event A belongs to class or process B; (ii) availability of instances or scenarios, which is often employed when people are asked to assess the frequency of a class or the plausibility of a particular development; and (iii) adjustment from an anchor, which is usually employed in numerical prediction when a relevant value is available. These heuristics are highly economical and usually effective, but they lead to systematic and predictable errors. A better understanding of these heuristics and of the biases to which they lead could improve judgements and decisions in situations of uncertainty.

  15. A nuclear heuristic for application to metaheuristics in-core fuel management optimization

    Energy Technology Data Exchange (ETDEWEB)

    Meneses, Anderson Alvarenga de Moura, E-mail: ameneses@lmp.ufrj.b [COPPE/Federal University of Rio de Janeiro, RJ (Brazil). Nuclear Engineering Program; Dalle Molle Institute for Artificial Intelligence (IDSIA), Manno-Lugano, TI (Switzerland); Gambardella, Luca Maria, E-mail: luca@idsia.c [Dalle Molle Institute for Artificial Intelligence (IDSIA), Manno-Lugano, TI (Switzerland); Schirru, Roberto, E-mail: schirru@lmp.ufrj.b [COPPE/Federal University of Rio de Janeiro, RJ (Brazil). Nuclear Engineering Program

    2009-07-01

    The In-Core Fuel Management Optimization (ICFMO) is a well-known problem of nuclear engineering whose features are complexity, high number of feasible solutions, and a complex evaluation process with high computational cost, thus it is prohibitive to have a great number of evaluations during an optimization process. Heuristics are criteria or principles for deciding which among several alternative courses of action are more effective with respect to some goal. In this paper, we propose a new approach for the use of relational heuristics for the search in the ICFMO. The Heuristic is based on the reactivity of the fuel assemblies and their position into the reactor core. It was applied to random search, resulting in less computational effort concerning the number of evaluations of loading patterns during the search. The experiments demonstrate that it is possible to achieve results comparable to results in the literature, for future application to metaheuristics in the ICFMO. (author)

  16. A heuristic and hybrid method for the tank allocation problem in maritime bulk shipping

    DEFF Research Database (Denmark)

    Vilhelmsen, Charlotte; Larsen, Jesper; Lusby, Richard Martin

    2016-01-01

    In bulk shipping, ships often have multiple tanks and carry multiple inhomogeneous products at a time. When operating such ships it is therefore a major challenge to decide how to best allocate cargoes to available tanks while taking into account tank capacity, safety restrictions, ship stability...... finding a feasible solution. We have developed a heuristic that can efficiently find feasible cargo allocations. Computational results show that it can solve 99 % of the considered instances within 0.4 s and all of them if allowed longer time. We have also modified an optimality based method from...... the literature. The heuristic is much faster than this modified method on the vast majority of considered instances. However, the heuristic struggles on two instances which are relatively quickly solved by the modified optimality based method. These two methods therefore complement each other nicely and so, we...

  17. A Heuristic and Hybrid Method for the Tank Allocation Problem in Maritime Bulk Shipping

    DEFF Research Database (Denmark)

    Vilhelmsen, Charlotte; Larsen, Jesper; Lusby, Richard Martin

    In bulk shipping, ships often have multiple tanks and carry multiple inhomogeneous products at a time. When operating such ships it is therefore a major challenge to decide how to best allocate cargoes to available tanks while taking into account tank capacity, safety restrictions, ship stability...... finding a feasible solution. We have developed a heuristic that can efficiently find feasible cargo allocations. Computational results show that it can solve 99% of the considered instances within 0.4 seconds and all of them if allowed longer time. We have also modified an optimality based method from...... the literature. The heuristic is much faster than this modified method on the vast majority of considered instances. However, the heuristic struggles on two instances which are relatively quickly solved by the modified optimality based method. These two methods therefore complement each other nicely and so, we...

  18. A nuclear heuristic for application to metaheuristics in-core fuel management optimization

    International Nuclear Information System (INIS)

    Meneses, Anderson Alvarenga de Moura; Gambardella, Luca Maria; Schirru, Roberto

    2009-01-01

    The In-Core Fuel Management Optimization (ICFMO) is a well-known problem of nuclear engineering whose features are complexity, high number of feasible solutions, and a complex evaluation process with high computational cost, thus it is prohibitive to have a great number of evaluations during an optimization process. Heuristics are criteria or principles for deciding which among several alternative courses of action are more effective with respect to some goal. In this paper, we propose a new approach for the use of relational heuristics for the search in the ICFMO. The Heuristic is based on the reactivity of the fuel assemblies and their position into the reactor core. It was applied to random search, resulting in less computational effort concerning the number of evaluations of loading patterns during the search. The experiments demonstrate that it is possible to achieve results comparable to results in the literature, for future application to metaheuristics in the ICFMO. (author)

  19. COMPARISON BETWEEN MIXED INTEGER PROGRAMMING WITH HEURISTIC METHOD FOR JOB SHOP SCHEDULING WITH SEPARABLE SEQUENCE-DEPENDENT SETUPS

    Directory of Open Access Journals (Sweden)

    I Gede Agus Widyadana

    2001-01-01

    Full Text Available The decisions to choose appropriate tools for solving industrial problems are not just tools that achieve optimal solution only but it should consider computation time too. One of industrial problems that still difficult to achieve both criteria is scheduling problem. This paper discuss comparison between mixed integer programming which result optimal solution and heuristic method to solve job shop scheduling problem with separable sequence-dependent setup. The problems are generated and the result shows that the heuristic methods still cannot satisfy optimal solution.

  20. Application of heuristic and machine-learning approach to engine model calibration

    Science.gov (United States)

    Cheng, Jie; Ryu, Kwang R.; Newman, C. E.; Davis, George C.

    1993-03-01

    Automation of engine model calibration procedures is a very challenging task because (1) the calibration process searches for a goal state in a huge, continuous state space, (2) calibration is often a lengthy and frustrating task because of complicated mutual interference among the target parameters, and (3) the calibration problem is heuristic by nature, and often heuristic knowledge for constraining a search cannot be easily acquired from domain experts. A combined heuristic and machine learning approach has, therefore, been adopted to improve the efficiency of model calibration. We developed an intelligent calibration program called ICALIB. It has been used on a daily basis for engine model applications, and has reduced the time required for model calibrations from many hours to a few minutes on average. In this paper, we describe the heuristic control strategies employed in ICALIB such as a hill-climbing search based on a state distance estimation function, incremental problem solution refinement by using a dynamic tolerance window, and calibration target parameter ordering for guiding the search. In addition, we present the application of a machine learning program called GID3* for automatic acquisition of heuristic rules for ordering target parameters.

  1. On the suitability of fast and frugal heuristics for designing values clarification methods in patient decision aids: a critical analysis.

    Science.gov (United States)

    Pieterse, Arwen H; de Vries, Marieke

    2013-09-01

    Increasingly, patient decision aids and values clarification methods (VCMs) are being developed to support patients in making preference-sensitive health-care decisions. Many VCMs encourage extensive deliberation about options, without solid theoretical or empirical evidence showing that deliberation is advantageous. Research suggests that simple, fast and frugal heuristic decision strategies sometimes result in better judgments and decisions. Durand et al. have developed two fast and frugal heuristic-based VCMs. To critically analyse the suitability of the 'take the best' (TTB) and 'tallying' fast and frugal heuristics in the context of patient decision making. Analysis of the structural similarities between the environments in which the TTB and tallying heuristics have been proven successful and the context of patient decision making and of the potential of these heuristic decision processes to support patient decision making. The specific nature of patient preference-sensitive decision making does not seem to resemble environments in which the TTB and tallying heuristics have proven successful. Encouraging patients to consider less rather than more relevant information potentially even deteriorates their values clarification process. Values clarification methods promoting the use of more intuitive decision strategies may sometimes be more effective. Nevertheless, we strongly recommend further theoretical thinking about the expected value of such heuristics and of other more intuitive decision strategies in this context, as well as empirical assessments of the mechanisms by which inducing such decision strategies may impact the quality and outcome of values clarification. © 2011 John Wiley & Sons Ltd.

  2. Age Effects and Heuristics in Decision Making.

    Science.gov (United States)

    Besedeš, Tibor; Deck, Cary; Sarangi, Sudipta; Shor, Mikhael

    2012-05-01

    Using controlled experiments, we examine how individuals make choices when faced with multiple options. Choice tasks are designed to mimic the selection of health insurance, prescription drug, or retirement savings plans. In our experiment, available options can be objectively ranked allowing us to examine optimal decision making. First, the probability of a person selecting the optimal option declines as the number of options increases, with the decline being more pronounced for older subjects. Second, heuristics differ by age with older subjects relying more on suboptimal decision rules. In a heuristics validation experiment, older subjects make worse decisions than younger subjects.

  3. Educational gaps and solutions for early-career nurse managers' education and participation in quality improvement.

    Science.gov (United States)

    Djukic, Maja; Kovner, Christine T; Brewer, Carol S; Fatehi, Farida; Jun, Jin

    2015-04-01

    The objective of this study was to examine early-career frontline nurse managers' (FLNMs') reported educational preparedness and participation in quality improvement (QI). Frontline nurse managers are vitally important for leading QI. However, it is not well known if they have adequate knowledge and skills to lead this important function. We examined cross-sectional survey data from 42 FLNMs using descriptive statistics. About 30% of FLNMs reported being very prepared across 12 measured QI skills by schools or employers and 35% reported participating in a specific clinical effort to improve patient care on their unit more than once a month. More than 50% reported having good organizational support for QI, but only about 30% reported being rewarded for their contributions to QI. Our study highlights opportunities for development in QI for FLNMs and offers some solutions for nurse executives that can bridge the educational gaps.

  4. Heuristic evaluation of online COPD respiratory therapy and education video resource center.

    Science.gov (United States)

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2014-10-01

    Abstract Purpose: Because of limited accessibility to pulmonary rehabilitation programs, patients with chronic obstructive pulmonary disease (COPD) are infrequently provided with patient education resources. To help educate patients with COPD on how to live a better life with diminished breathing capacity, we developed a novel social media resource center containing COPD respiratory therapy and education videos called "COPDFlix." A heuristic evaluation of COPDFlix was conducted as part of a larger study to determine whether the prototype was successful in adhering to formal Web site usability guidelines for older adults. A purposive sample of three experts, with expertise in Web design and health communications technology, was recruited (a) to identify usability violations and (b) to propose solutions to improve the functionality of the COPDFlix prototype. Each expert evaluated 18 heuristics in four categories of task-based criteria (i.e., interaction and navigation, information architecture, presentation design, and information design). Seventy-six subcriteria across these four categories were assessed. Quantitative ratings and qualitative comments from each expert were compiled into a single master list, noting the violated heuristic and type/location of problem(s). Sixty-one usability violations were identified across the 18 heuristics. Evaluators rated the majority of heuristic subcriteria as either a "minor hindrance" (n=32) or "no problem" (n=132). Moreover, only 2 of the 18 heuristic categories were noted as "major" violations, with mean severity scores of ≥3. Mixed-methods data analysis helped the multidisciplinary research team to categorize and prioritize usability problems and solutions, leading to 26 discrete design modifications within the COPDFlix prototype.

  5. A heuristic for the inventory management of smart vending machine systems

    Directory of Open Access Journals (Sweden)

    Yang-Byung Park

    2012-12-01

    Full Text Available Purpose: The purpose of this paper is to propose a heuristic for the inventory management of smart vending machine systems with product substitution under the replenishment point, order-up-to level policy and to evaluate its performance.Design/methodology/approach: The heuristic is developed on the basis of the decoupled approach. An integer linear mathematical model is built to determine the number of product storage compartments and replenishment threshold for each smart vending machine in the system and the Clarke and Wright’s savings algorithm is applied to route vehicles for inventory replenishments of smart vending machines that share the same delivery days. Computational experiments are conducted on several small-size test problems to compare the proposed heuristic with the integrated optimization mathematical model with respect to system profit. Furthermore, a sensitivity analysis is carried out on a medium-size test problem to evaluate the effect of the customer service level on system profit using a computer simulation.Findings: The results show that the proposed heuristic yielded pretty good solutions with 5.7% error rate on average compared to the optimal solutions. The proposed heuristic took about 3 CPU minutes on average in the test problems being consisted of 10 five-product smart vending machines. It was confirmed that the system profit is significantly affected by the customer service level.Originality/value: The inventory management of smart vending machine systems is newly treated. Product substitutions are explicitly considered in the model. The proposed heuristic is effective as well as efficient. It can be easily modified for application to various retail vending settings under a vendor-managed inventory scheme with POS system.

  6. Influence of acute stress on decision outcomes and heuristics.

    Science.gov (United States)

    Hepler, Teri J; Kovacs, Attila J

    2017-03-01

    The purpose of this study was to examine the take-the-first (TTF) heuristic and decision outcomes in sports under conditions of no, mental, and physical stress. Participants (N.=68) performed 8 video decision-making trials under each of 3 stress conditions: no stress (counting backwards), mental stress (mental serial subtraction), and physical stress (running on treadmill at 13 RPE). Prior to each decision-making trial, participants were exposed to 30 seconds of stress. The decision-making task required participants to watch a video depicting an offensive situation in basketball and then decide what the player with the ball should do next. No differences were found between the 3 stress conditions on TTF frequency, number of options generated, quality of first generated option, or final decision quality. However, participants performing under conditions of no stress and physical stress generated their first option and made their final decision faster than they did when making decisions under mental stress. Overall, results suggest that mental stress impairs decision speed and that TTF is an ecologically rationale heuristic in dynamic, time-pressured situations.

  7. Fuel lattice design using heuristics and new strategies

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Pelta, D. A. [ETS Ingenieria Informatica y Telecomunicaciones, Universidad de Granada, Daniel Saucedo Aranda s/n, 18071 Granada (Spain); Campos S, Y., E-mail: juanjose.ortiz@inin.gob.m [IPN, Escuela Superior de Fisica y Matematicas, Unidad Profesional Adolfo Lopez Mateos, Edif. 9, 07738 Mexico D. F. (Mexico)

    2010-10-15

    This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)

  8. Fuel lattice design using heuristics and new strategies

    International Nuclear Information System (INIS)

    Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R.; Pelta, D. A.; Campos S, Y.

    2010-10-01

    This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)

  9. Effects of four additive solutions on canine leukoreduced red cell concentrate quality during storage.

    Science.gov (United States)

    Lacerda, Luciana A; Hlavac, Nicole R C; Terra, Silvia R; Back, Franciele P; Jane Wardrop, K; González, Félix H D

    2014-09-01

    Additive solutions (AS) and prestorage leukoreduction (LR) are important tools used to maintain erythrocyte viability during storage and avoid transfusion reactions in recipients, respectively. The purpose of the study was to determine the efficacy of a WBC filter (Immugard IIIRC) and compare the effect of 4 AS (phosphate-adenine-glucose-guanosine-gluconate-mannitol [PAGGGM], saline-adenine-glucose-mannitol [SAGM], Adsol, Optisol) on the in vitro quality of canine leukoreduced packed RBC units (pRBC) stored for 41 days. Five hundred milliliters of blood were collected from 8 healthy dogs each into 70 mL of citrate-phosphate-dextrose (CPD) solution, and were leukoreduced by a polyurethane filter. pRBC of each dog were divided equally into 4 bags containing a different AS. Bags were stored for 41 days at 4°C and evaluated every 10 days. Variables analyzed included pH, PCV, and% hemolysis, and lactate, glucose, potassium, sodium, ATP, and 2,3-diphosphoglycerate (2,3-DPG) concentrations. The LR resulted in residual WBC counts comparable to human standards. During storage, pH, and glucose, 2,3-DPG, and ATP concentrations decreased, and hemolysis, and lactate, sodium, and potassium concentrations increased (P 2,3-DPG concentrations. When compared with day 1 values, significant changes were seen in these variables by day 31 with all AS. © 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology.

  10. POSTHARVEST QUALITY OF FEIJOA FLOWERS TREATED WITH DIFFERENT PRESERVATIVE SOLUTIONS AND 1-METHYLCYCLOPROPENE

    Directory of Open Access Journals (Sweden)

    ALEXANDRA GOEDE DE SOUZA

    Full Text Available ABSTRACT This study was carried out to assess the postharvest quality preservation of feijoa(Acca sellowiana Berg flowers in response to treatments with different preservative solutions and 1-methylcyclopropene (1-MCP. Recently opened feijoa flowers were harvested in the morning (between 8h and 10h and immediately after pulsed with preservative solutions of salicylic acid, ascorbic acid and sucrose, all at doses of 0 (control, 2, 5 or 10%, and treated with 1-MCP at doses of 0 (control, 250, 500 or 1,000 nL L-1. Each trial with preservative solutions or 1-MCP treatment was a distinct experiment conducted in a completely randomized design with four replicates, each replicate with four flowers. After the treatment, the flowers were stored for 12 days at 10±1 oC and 85±5% RH. At every two-days intervals the flower petals were visually evaluated for wilting and darkening according to a hedonic scale varying from 1 (less intense to 5 (more intense. Petal color was ranked from 1 (intense pink to 5 (white. The 1-MCP at 500 nL L-1 and the salicylic acid (regardless of the dose delayed the changes of petal color for up to eight and six days of storage, respectively. Flowers treated with salicylic acid, 1-MCP or ascorbic acid had a more substantial delay in petal wilting. Flowers treated with salicylic acid had wilting rank of 2 after six days of storage when treated with doses of 5% or 10%, and after eight days when treated with the dose of 2%, while flowers treated with 1-MCP at 500 and 1,000 nL L-1 and ascorbic acid at 2% and 5% had wilting rank of 2 after four days of storage. The most substantial delay of petal darkening (until the fourth day of storage was achieved with 1-MCP at 500 nL L-1.

  11. A CDT-Based Heuristic Zone Design Approach for Economic Census Investigators

    Directory of Open Access Journals (Sweden)

    Changixu Cheng

    2015-01-01

    Full Text Available This paper addresses a special zone design problem for economic census investigators that is motivated by a real-world application. This paper presented a heuristic multikernel growth approach via Constrained Delaunay Triangulation (CDT. This approach not only solved the barriers problem but also dealt with the polygon data in zoning procedure. In addition, it uses a new heuristic method to speed up the zoning process greatly on the premise of the required quality of zoning. At last, two special instances for economic census were performed, highlighting the performance of this approach.

  12. Assessing Use of Cognitive Heuristic Representativeness in Clinical Reasoning

    OpenAIRE

    Payne, Velma L.; Crowley, Rebecca S.

    2008-01-01

    We performed a pilot study to investigate use of the cognitive heuristic Representativeness in clinical reasoning. We tested a set of tasks and assessments to determine whether subjects used the heuristics in reasoning, to obtain initial frequencies of heuristic use and related cognitive errors, and to collect cognitive process data using think-aloud techniques. The study investigates two aspects of the Representativeness heuristic - judging by perceived frequency and representativeness as ca...

  13. Application of Fuzzy Sets for the Improvement of Routing Optimization Heuristic Algorithms

    Directory of Open Access Journals (Sweden)

    Mattas Konstantinos

    2016-12-01

    Full Text Available The determination of the optimal circular path has become widely known for its difficulty in producing a solution and for the numerous applications in the scope of organization and management of passenger and freight transport. It is a mathematical combinatorial optimization problem for which several deterministic and heuristic models have been developed in recent years, applicable to route organization issues, passenger and freight transport, storage and distribution of goods, waste collection, supply and control of terminals, as well as human resource management. Scope of the present paper is the development, with the use of fuzzy sets, of a practical, comprehensible and speedy heuristic algorithm for the improvement of the ability of the classical deterministic algorithms to identify optimum, symmetrical or non-symmetrical, circular route. The proposed fuzzy heuristic algorithm is compared to the corresponding deterministic ones, with regard to the deviation of the proposed solution from the best known solution and the complexity of the calculations needed to obtain this solution. It is shown that the use of fuzzy sets reduced up to 35% the deviation of the solution identified by the classical deterministic algorithms from the best known solution.

  14. New heuristic method for the optimization of product mix based on theory of constraints and knapsack problem

    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.

  15. Applying usability heuristics to radiotherapy systems

    International Nuclear Information System (INIS)

    Chan, Alvita J.; Islam, Mohammad K.; Rosewall, Tara; Jaffray, David A.; Easty, Anthony C.; Cafazzo, Joseph A.

    2012-01-01

    Background and purpose: Heuristic evaluations have been used to evaluate safety of medical devices by identifying and assessing usability issues. Since radiotherapy treatment delivery systems often consist of multiple complex user-interfaces, a heuristic evaluation was conducted to assess the potential safety issues of such a system. Material and methods: A heuristic evaluation was conducted to evaluate the treatment delivery system at Princess Margaret Hospital (Toronto, Canada). Two independent evaluators identified usability issues with the user-interfaces and rated the severity of each issue. Results: The evaluators identified 75 usability issues in total. Eighteen of them were rated as high severity, indicating the potential to have a major impact on patient safety. A majority of issues were found on the record and verify system, and many were associated with the patient setup process. While the hospital has processes in place to ensure patient safety, recommendations were developed to further mitigate the risks of potential consequences. Conclusions: Heuristic evaluation is an efficient and inexpensive method that can be successfully applied to radiotherapy delivery systems to identify usability issues and improve patient safety. Although this study was conducted only at one site, the findings may have broad implications for the design of these systems.

  16. Can the inherence heuristic explain vitalistic reasoning?

    Science.gov (United States)

    Bastian, Brock

    2014-10-01

    Inherence is an important component of psychological essentialism. By drawing on vitalism as a way in which to explain this link, however, the authors appear to conflate causal explanations based on fixed features with those based on general causal forces. The disjuncture between these two types of explanatory principles highlights potential new avenues for the inherence heuristic.

  17. Fast heuristics for a dynamic paratransit problem

    NARCIS (Netherlands)

    Cremers, M.L.A.G.; Klein Haneveld, W.K.; van der Vlerk, M.H.

    2008-01-01

    In a previous paper we developed a non-standard two-stage recourse model for the dynamic day-ahead paratransit planning problem. Two heuristics, which are frequently applied in the recourse model, contain many details which leads to large CPU times to solve instances of relatively small size. In

  18. A Heuristic for Improving Transmedia Exhibition Experience

    DEFF Research Database (Denmark)

    Selvadurai, Vashanth; Rosenstand, Claus Andreas Foss

    2017-01-01

    in the scientific field of designing transmedia experience in an exhibition context that links the pre- and post-activities to the actual visit (during-activities). The result of this study is a preliminary heuristic for establishing a relation between the platform and content complexity in transmedia exhibitions....

  19. Heuristics for speeding up gaze estimation

    DEFF Research Database (Denmark)

    Leimberg, Denis; Vester-Christensen, Martin; Ersbøll, Bjarne Kjær

    2005-01-01

    A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the method with a state of the art active contour approach, showing that the heuristic method is more...

  20. The Heuristic Interpretation of Box Plots

    Science.gov (United States)

    Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

    2013-01-01

    Box plots are frequently used, but are often misinterpreted by students. Especially the area of the box in box plots is often misinterpreted as representing number or proportion of observations, while it actually represents their density. In a first study, reaction time evidence was used to test whether heuristic reasoning underlies this…

  1. Engineering applications of heuristic multilevel optimization methods

    Science.gov (United States)

    Barthelemy, Jean-Francois M.

    1989-01-01

    Some engineering applications of heuristic multilevel optimization methods are presented and the discussion focuses on the dependency matrix that indicates the relationship between problem functions and variables. Coordination of the subproblem optimizations is shown to be typically achieved through the use of exact or approximate sensitivity analysis. Areas for further development are identified.

  2. A Heuristic for the Teaching of Persuasion.

    Science.gov (United States)

    Schell, John F.

    Interpreting Aristotle's criteria for persuasive writing--ethos, logos, and pathos--as a concern for writer, language, and audience creates both an effective model for persuasive writing and a structure around which to organize discussions of relevant rhetorical issues. Use of this heuristic to analyze writing style, organization, and content…

  3. Fourth Graders' Heuristic Problem-Solving Behavior.

    Science.gov (United States)

    Lee, Kil S.

    1982-01-01

    Eight boys and eight girls from a rural elementary school participated in the investigation. Specific heuristics were adopted from Polya; and the students selected represented two substages of Piaget's concrete operational stage. Five hypotheses were generated, based on observed results and the study's theoretical rationale. (MP)

  4. Heuristic Decision Making in Network Linking

    NARCIS (Netherlands)

    M.J.W. Harmsen - Van Hout (Marjolein); B.G.C. Dellaert (Benedict); P.J.J. Herings (Jean-Jacques)

    2015-01-01

    textabstractNetwork formation among individuals constitutes an important part of many OR processes, but relatively little is known about how individuals make their linking decisions in networks. This article provides an investigation of heuristic effects in individual linking decisions for

  5. Investigating Heuristic Evaluation: A Case Study.

    Science.gov (United States)

    Goldman, Kate Haley; Bendoly, Laura

    When museum professionals speak of evaluating a web site, they primarily mean formative evaluation, and by that they primarily mean testing the usability of the site. In the for-profit world, usability testing is a multi-million dollar industry, while non-profits often rely on far too few dollars to do too much. Hence, heuristic evaluation is one…

  6. Internal Medicine residents use heuristics to estimate disease probability

    Directory of Open Access Journals (Sweden)

    Sen Phang

    2015-12-01

    Conclusions: Our findings suggest that despite previous exposure to the use of Bayesian reasoning, residents use heuristics, such as the representative heuristic and anchoring with adjustment, to estimate probabilities. Potential reasons for attribute substitution include the relative cognitive ease of heuristics vs. Bayesian reasoning or perhaps residents in their clinical practice use gist traces rather than precise probability estimates when diagnosing.

  7. Heuristics Made Easy: An Effort-Reduction Framework

    Science.gov (United States)

    Shah, Anuj K.; Oppenheimer, Daniel M.

    2008-01-01

    In this article, the authors propose a new framework for understanding and studying heuristics. The authors posit that heuristics primarily serve the purpose of reducing the effort associated with a task. As such, the authors propose that heuristics can be classified according to a small set of effort-reduction principles. The authors use this…

  8. A Variable-Selection Heuristic for K-Means Clustering.

    Science.gov (United States)

    Brusco, Michael J.; Cradit, J. Dennis

    2001-01-01

    Presents a variable selection heuristic for nonhierarchical (K-means) cluster analysis based on the adjusted Rand index for measuring cluster recovery. Subjected the heuristic to Monte Carlo testing across more than 2,200 datasets. Results indicate that the heuristic is extremely effective at eliminating masking variables. (SLD)

  9. Heuristic Diagrams as a Tool to Teach History of Science

    Science.gov (United States)

    Chamizo, Jose A.

    2012-01-01

    The graphic organizer called here heuristic diagram as an improvement of Gowin's Vee heuristic is proposed as a tool to teach history of science. Heuristic diagrams have the purpose of helping students (or teachers, or researchers) to understand their own research considering that asks and problem-solving are central to scientific activity. The…

  10. Improving performances of suboptimal greedy iterative biclustering heuristics via localization.

    Science.gov (United States)

    Erten, Cesim; Sözdinler, Melih

    2010-10-15

    Biclustering gene expression data is the problem of extracting submatrices of genes and conditions exhibiting significant correlation across both the rows and the columns of a data matrix of expression values. Even the simplest versions of the problem are computationally hard. Most of the proposed solutions therefore employ greedy iterative heuristics that locally optimize a suitably assigned scoring function. We provide a fast and simple pre-processing algorithm called localization that reorders the rows and columns of the input data matrix in such a way as to group correlated entries in small local neighborhoods within the matrix. The proposed localization algorithm takes its roots from effective use of graph-theoretical methods applied to problems exhibiting a similar structure to that of biclustering. In order to evaluate the effectivenesss of the localization pre-processing algorithm, we focus on three representative greedy iterative heuristic methods. We show how the localization pre-processing can be incorporated into each representative algorithm to improve biclustering performance. Furthermore, we propose a simple biclustering algorithm, Random Extraction After Localization (REAL) that randomly extracts submatrices from the localization pre-processed data matrix, eliminates those with low similarity scores, and provides the rest as correlated structures representing biclusters. We compare the proposed localization pre-processing with another pre-processing alternative, non-negative matrix factorization. We show that our fast and simple localization procedure provides similar or even better results than the computationally heavy matrix factorization pre-processing with regards to H-value tests. We next demonstrate that the performances of the three representative greedy iterative heuristic methods improve with localization pre-processing when biological correlations in the form of functional enrichment and PPI verification constitute the main performance

  11. A manpower scheduling heuristic for aircraft maintenance application

    Science.gov (United States)

    Sze, San-Nah; Sze, Jeeu-Fong; Chiew, Kang-Leng

    2012-09-01

    This research studies a manpower scheduling for aircraft maintenance, focusing on in-flight food loading operation. A group of loading teams with flexible shifts is required to deliver and upload packaged meals from the ground kitchen to aircrafts in multiple trips. All aircrafts must be served within predefined time windows. The scheduling process takes into account of various constraints such as meal break allocation, multi-trip traveling and food exposure time limit. Considering the aircrafts movement and predefined maximum working hours for each loading team, the main objective of this study is to form an efficient roster by assigning a minimum number of loading teams to the aircrafts. We proposed an insertion based heuristic to generate the solutions in a short period of time for large instances. This proposed algorithm is implemented in various stages for constructing trips due to the presence of numerous constraints. The robustness and efficiency of the algorithm is demonstrated in computational results. The results show that the insertion heuristic more efficiently outperforms the company's current practice.

  12. Solving Inventory Routing Problems Using Location Based Heuristics

    Directory of Open Access Journals (Sweden)

    Paweł Hanczar

    2014-01-01

    Full Text Available Inventory routing problems (IRPs occur where vendor managed inventory replenishment strategies are implemented in supply chains. These problems are characterized by the presence of both transportation and inventory considerations, either as parameters or constraints. The research presented in this paper aims at extending IRP formulation developed on the basis of location based heuristics proposed by Bramel and Simchi-Levi and continued by Hanczar. In the first phase of proposed algorithms, mixed integer programming is used to determine the partitioning of customers as well as dates and quantities of deliveries. Then, using 2-opt algorithm for solving the traveling sales-person problem the optimal routes for each partition are determined. In the main part of research the classical formulation is extended by additional constraints (visit spacing, vehicle filling rate, driver (vehicle consistency, and heterogeneous fleet of vehicles as well as the additional criteria are discussed. Then the impact of using each of proposed extensions for solution possibilities is evaluated. The results of computational tests are presented and discussed. Obtained results allow to conclude that the location based heuristics should be considered when solving real life instances of IRP. (original abstract

  13. Heuristics structure and pervade formal risk assessment.

    Science.gov (United States)

    MacGillivray, Brian H

    2014-04-01

    Lay perceptions of risk appear rooted more in heuristics than in reason. A major concern of the risk regulation literature is that such "error-strewn" perceptions may be replicated in policy, as governments respond to the (mis)fears of the citizenry. This has led many to advocate a relatively technocratic approach to regulating risk, characterized by high reliance on formal risk and cost-benefit analysis. However, through two studies of chemicals regulation, we show that the formal assessment of risk is pervaded by its own set of heuristics. These include rules to categorize potential threats, define what constitutes valid data, guide causal inference, and to select and apply formal models. Some of these heuristics lay claim to theoretical or empirical justifications, others are more back-of-the-envelope calculations, while still more purport not to reflect some truth but simply to constrain discretion or perform a desk-clearing function. These heuristics can be understood as a way of authenticating or formalizing risk assessment as a scientific practice, representing a series of rules for bounding problems, collecting data, and interpreting evidence (a methodology). Heuristics are indispensable elements of induction. And so they are not problematic per se, but they can become so when treated as laws rather than as contingent and provisional rules. Pitfalls include the potential for systematic error, masking uncertainties, strategic manipulation, and entrenchment. Our central claim is that by studying the rules of risk assessment qua rules, we develop a novel representation of the methods, conventions, and biases of the prior art. © 2013 Society for Risk Analysis.

  14. A sequential insertion heuristic for the initial solution to a ...

    African Journals Online (AJOL)

    The Vehicle Routing Problem (VRP) is a well-researched problem in the Operations Research literature. It is the view of the authors of this paper that the various VRP variants have been researched in isolation. This paper embodies an attempt to integrate three specific variants of the VRP, namely the VRP with multiple time ...

  15. A sequential insertion heuristic for the initial solution to a ...

    African Journals Online (AJOL)

    This paper embodies an attempt to integrate three specific variants of the VRP, namely the ... regards to logistics and vehicle routing. The VRP may be ... neous, that is, where the fleet is composed of vehicles with different capacities and costs.

  16. Commercial Territory Design for a Distribution Firm with New Constructive and Destructive Heuristics

    Directory of Open Access Journals (Sweden)

    Jaime

    2012-02-01

    Full Text Available A commercial territory design problem with compactness maximization criterion subject to territory balancing and connectivity is addressed. Four new heuristics based on Greedy Randomized Adaptive Search Procedures within a location-allocation scheme for this NP-hard combinatorial optimization problem are proposed. The first three (named GRLH1, GRLH2, and GRDL build the territories simultaneously. Their construction phase consists of two parts: a location phase where territory seeds are identified, and an allocation phase where the remaining basic units are iteratively assigned to a territory. In contrast, the other heuristic (named SLA builds the territories one at a time. Empirical results reveals that GRLH1 and GRLH2 find near-optimal or optimal solutions to relatively small instances, where exact solutions could be found. The proposed procedures are relatively fast. We carried out a comparison between the proposed heuristic procedures and the existing method in larger instances. It was observed the proposed heuristic GRLH1 produced competitive results with respect to the existing approach.

  17. Heuristic Evaluation of E-Learning Courses: A Comparative Analysis of Two E-Learning Heuristic Sets

    Science.gov (United States)

    Zaharias, Panagiotis; Koutsabasis, Panayiotis

    2012-01-01

    Purpose: The purpose of this paper is to discuss heuristic evaluation as a method for evaluating e-learning courses and applications and more specifically to investigate the applicability and empirical use of two customized e-learning heuristic protocols. Design/methodology/approach: Two representative e-learning heuristic protocols were chosen…

  18. Assessment of quality of platelets preserved in plasma and platelet additive solution: A Malaysian experience

    Directory of Open Access Journals (Sweden)

    Munirah Binti Mokhtar

    2016-01-01

    Full Text Available Background: A use of platelet additives solution (PAS improves storage conditions so as to give increased shelf life to platelets and to maintain hemostatic function. Objective: The present study was aimed to compare in vitro quality of platelet rich plasma (PRP-derived platelet concentrate (PC during extended period of storage in plasma and in additive solution (Composol PS and Fresenius. Study Design: Randomized 19 PCs each were used in the study for plasma and PAS as the storage medium. The measurement parameters, including pH, total white blood cell (WBC count, total platelet count, and platelet activation rate, were studied on day 1, day 5, and day 8 of the storage period. The sterility test was carried out on the eighth day of storage. Results: pH of PC suspended in PAS was significantly lower as compared to that in plasma (P < 0.001 for all the three days of sampling. The WBC count, both in plasma and in PAS, showed an acceptable values of being <0.2 Χ 10 9 /unit during the storage period. Platelet count in PAS was higher as compared to that in plasma, though it was not statistically significant. While both the groups showed increased platelet activation rate during the storage, the PCs suspended in PAS showed significantly higher platelet activation rate (p0.001. Results from sterility test showed no bacterial growth in the PCs in both the groups. Conclusion: Most parameters studied on platelet storage in suspending medium of native plasma and PAS remained well within the acceptable limits. However, the pH values and platelet activation rate significantly differed in PAS as compared with plasma.

  19. Effects of some preservative solutions on vase life and keeping quality of snapdragon (Antirrhinum majus L. cut flowers

    Directory of Open Access Journals (Sweden)

    Abdul-Wasea A. Asrar

    2012-01-01

    Full Text Available The effect of selected chemical agents used as preservative solutions to improve the keeping quality of cut snapdragon (Antirrhinum majus L. cv. Yellow Butterfly flowers had been studied. These preservative solutions (treatments were: 2% sucrose, 200 ppm 8-hydroxyquinoline sulfate (8-HQS, pulsing treatment with 200 ppm 8-HQS in combination with 2% sucrose for 12 h, pulsing the spikes with 0.2 mM silver thiosulfate (STS for 1 h, pulsing with 0.2 mM STS for 1 h followed by 2% sucrose solution, or distilled water used as control. The results showed that all treatments had improved the keeping quality and vase life of the cut flowers comparing to control ones. Among all these treatments, the 8-HQS plus 2% sucrose treatment showed best water uptake, water balance, percentage of maximum increase in fresh weight of the cut flower stem and vase life which was extended up to 18 days. Moreover, this keeping solution treatment retarded the degradation of chlorophyll as well as carbohydrate of the cut flowers during their postharvest life. It has been concluded that 200 ppm 8-HQS combined with 2% sucrose solution has the potential to be used as a commercial cut flower preservative solution to delay flower senescence, enhance post-harvest quality and prolong the vase life of cut snapdragon flowers.

  20. Identifying product development crises: The potential of adaptive heuristics

    DEFF Research Database (Denmark)

    Münzberger, C.; Stingl, Verena; Oehmen, Josef

    2017-01-01

    This paper introduces adaptive heuristics as a tool to identify crises in design projects and highlights potential applications of these heuristics as decision support tool for crisis identification. Crises may emerge slowly or suddenly, and often have ambiguous signals. Thus the identification...... for the application of heuristics in design sciences. To achieve this, the paper compares crises to 'business as usual', and presents sixteen indicators for emerging crises. These indicators are potential cues for adaptive heuristics. Specifically three adaptive heuristics, One-single-cue, Fast-and-Frugal-Trees...

  1. Automatic Overset Grid Generation with Heuristic Feedback Control

    Science.gov (United States)

    Robinson, Peter I.

    2001-01-01

    An advancing front grid generation system for structured Overset grids is presented which automatically modifies Overset structured surface grids and control lines until user-specified grid qualities are achieved. The system is demonstrated on two examples: the first refines a space shuttle fuselage control line until global truncation error is achieved; the second advances, from control lines, the space shuttle orbiter fuselage top and fuselage side surface grids until proper overlap is achieved. Surface grids are generated in minutes for complex geometries. The system is implemented as a heuristic feedback control (HFC) expert system which iteratively modifies the input specifications for Overset control line and surface grids. It is developed as an extension of modern control theory, production rules systems and subsumption architectures. The methodology provides benefits over the full knowledge lifecycle of an expert system for knowledge acquisition, knowledge representation, and knowledge execution. The vector/matrix framework of modern control theory systematically acquires and represents expert system knowledge. Missing matrix elements imply missing expert knowledge. The execution of the expert system knowledge is performed through symbolic execution of the matrix algebra equations of modern control theory. The dot product operation of matrix algebra is generalized for heuristic symbolic terms. Constant time execution is guaranteed.

  2. Assessing the use of cognitive heuristic representativeness in clinical reasoning.

    Science.gov (United States)

    Payne, Velma L; Crowley, Rebecca S; Crowley, Rebecca

    2008-11-06

    We performed a pilot study to investigate use of the cognitive heuristic Representativeness in clinical reasoning. We tested a set of tasks and assessments to determine whether subjects used the heuristics in reasoning, to obtain initial frequencies of heuristic use and related cognitive errors, and to collect cognitive process data using think-aloud techniques. The study investigates two aspects of the Representativeness heuristic - judging by perceived frequency and representativeness as causal beliefs. Results show that subjects apply both aspects of the heuristic during reasoning, and make errors related to misapplication of these heuristics. Subjects in this study rarely used base rates, showed significant variability in their recall of base rates, demonstrated limited ability to use provided base rates, and favored causal data in diagnosis. We conclude that the tasks and assessments we have developed provide a suitable test-bed to study the cognitive processes underlying heuristic errors.

  3. Assessing Use of Cognitive Heuristic Representativeness in Clinical Reasoning

    Science.gov (United States)

    Payne, Velma L.; Crowley, Rebecca S.

    2008-01-01

    We performed a pilot study to investigate use of the cognitive heuristic Representativeness in clinical reasoning. We tested a set of tasks and assessments to determine whether subjects used the heuristics in reasoning, to obtain initial frequencies of heuristic use and related cognitive errors, and to collect cognitive process data using think-aloud techniques. The study investigates two aspects of the Representativeness heuristic - judging by perceived frequency and representativeness as causal beliefs. Results show that subjects apply both aspects of the heuristic during reasoning, and make errors related to misapplication of these heuristics. Subjects in this study rarely used base rates, showed significant variability in their recall of base rates, demonstrated limited ability to use provided base rates, and favored causal data in diagnosis. We conclude that the tasks and assessments we have developed provide a suitable test-bed to study the cognitive processes underlying heuristic errors. PMID:18999140

  4. Reconsidering "evidence" for fast-and-frugal heuristics.

    Science.gov (United States)

    Hilbig, Benjamin E

    2010-12-01

    In several recent reviews, authors have argued for the pervasive use of fast-and-frugal heuristics in human judgment. They have provided an overview of heuristics and have reiterated findings corroborating that such heuristics can be very valid strategies leading to high accuracy. They also have reviewed previous work that implies that simple heuristics are actually used by decision makers. Unfortunately, concerning the latter point, these reviews appear to be somewhat incomplete. More important, previous conclusions have been derived from investigations that bear some noteworthy methodological limitations. I demonstrate these by proposing a new heuristic and provide some novel critical findings. Also, I review some of the relevant literature often not-or only partially-considered. Overall, although some fast-and-frugal heuristics indeed seem to predict behavior at times, there is little to no evidence for others. More generally, the empirical evidence available does not warrant the conclusion that heuristics are pervasively used.

  5. Defining Robust Recovery Solutions for Preserving Service Quality during Rail/Metro Systems Failure

    Directory of Open Access Journals (Sweden)

    Luca D'Acierno

    2016-11-01

    Full Text Available In this paper, we propose a sensitivity analysis for evaluating the effectiveness of recovery solutions in the case of disturbed rail operations. Indeed, when failures or breakdowns occur during daily service, new strategies have to be implemented so as to react appropriately and re-establish ordinary conditions as rapidly as possible. In this context, the use of rail simulation is vital: for each intervention strategy it provides the evaluation of interactions and performance analysis prior to actually implementing the corrective action. However, in most cases, simulation tasks are deterministic and fail to allow for the stochastic distribution of train performance and delays. Hence, the strategies adopted might not be robust enough to ensure effectiveness of the intervention. We therefore propose an off-line procedure for disruption management based on a microscopic and stochastic rail simulation which considers both service operation and travel demand. An application in the case of a real metro line in Naples (Italy shows the benefits of the proposed approach in terms of service quality.

  6. Storage costs and heuristics interact to produce patterns of aphasic sentence comprehension performance.

    Science.gov (United States)

    Clark, David Glenn

    2012-01-01

    Despite general agreement that aphasic individuals exhibit difficulty understanding complex sentences, the nature of sentence complexity itself is unresolved. In addition, aphasic individuals appear to make use of heuristic strategies for understanding sentences. This research is a comparison of predictions derived from two approaches to the quantification of sentence complexity, one based on the hierarchical structure of sentences, and the other based on dependency locality theory (DLT). Complexity metrics derived from these theories are evaluated under various assumptions of heuristic use. A set of complexity metrics was derived from each general theory of sentence complexity and paired with assumptions of heuristic use. Probability spaces were generated that summarized the possible patterns of performance across 16 different sentence structures. The maximum likelihood of comprehension scores of 42 aphasic individuals was then computed for each probability space and the expected scores from the best-fitting points in the space were recorded for comparison to the actual scores. Predictions were then compared using measures of fit quality derived from linear mixed effects models. All three of the metrics that provide the most consistently accurate predictions of patient scores rely on storage costs based on the DLT. Patients appear to employ an Agent-Theme heuristic, but vary in their tendency to accept heuristically generated interpretations. Furthermore, the ability to apply the heuristic may be degraded in proportion to aphasia severity. DLT-derived storage costs provide the best prediction of sentence comprehension patterns in aphasia. Because these costs are estimated by counting incomplete syntactic dependencies at each point in a sentence, this finding suggests that aphasia is associated with reduced availability of cognitive resources for maintaining these dependencies.

  7. Heuristic Optimization for the Discrete Virtual Power Plant Dispatch Problem

    DEFF Research Database (Denmark)

    Petersen, Mette Kirschmeyer; Hansen, Lars Henrik; Bendtsen, Jan Dimon

    2014-01-01

    We consider a Virtual Power Plant, which is given the task of dispatching a fluctuating power supply to a portfolio of flexible consumers. The flexible consumers are modeled as discrete batch processes, and the associated optimization problem is denoted the Discrete Virtual Power Plant Dispatch...... Problem. First NP-completeness of the Discrete Virtual Power Plant Dispatch Problem is proved formally. We then proceed to develop tailored versions of the meta-heuristic algorithms Hill Climber and Greedy Randomized Adaptive Search Procedure (GRASP). The algorithms are tuned and tested on portfolios...... of varying sizes. We find that all the tailored algorithms perform satisfactorily in the sense that they are able to find sub-optimal, but usable, solutions to very large problems (on the order of 10 5 units) at computation times on the scale of just 10 seconds, which is far beyond the capabilities...

  8. PROBLEM SOLVING IN SCHOOL MATHEMATICS BASED ON HEURISTIC STRATEGIES

    Directory of Open Access Journals (Sweden)

    NOVOTNÁ, Jarmila

    2014-03-01

    Full Text Available The paper describes one of the ways of developing pupils’ creative approach to problem solving. The described experiment is a part of a longitudinal research focusing on improvement of culture of problem solving by pupils. It deals with solving of problems using the following heuristic strategies: Analogy, Guess – check – revise, Systematic experimentation, Problem reformulation, Solution drawing, Way back and Use of graphs of functions. Most attention is paid to the question whether short-term work, in this case only over the period of three months, can result in improvement of pupils’ abilities to solve problems whose solving algorithms are easily accessible. It also answers the question which strategies pupils will prefer and with what results. The experiment shows that even short-term work can bear positive results as far as pupils’ approach to problem solving is concerned.

  9. A System for Automatically Generating Scheduling Heuristics

    Science.gov (United States)

    Morris, Robert

    1996-01-01

    The goal of this research is to improve the performance of automated schedulers by designing and implementing an algorithm by automatically generating heuristics by selecting a schedule. The particular application selected by applying this method solves the problem of scheduling telescope observations, and is called the Associate Principal Astronomer. The input to the APA scheduler is a set of observation requests submitted by one or more astronomers. Each observation request specifies an observation program as well as scheduling constraints and preferences associated with the program. The scheduler employs greedy heuristic search to synthesize a schedule that satisfies all hard constraints of the domain and achieves a good score with respect to soft constraints expressed as an objective function established by an astronomer-user.

  10. Steering urban environmental quality in a multi-level governance context. How can devolution be the solution to pollution?

    NARCIS (Netherlands)

    Stigt, van Rien; Driessen, Peter P.J.; Spit, Tejo

    2016-01-01

    Devolution is advocated as a solution to scale mismatches in urban environmental governance. However, urban environmental quality is a multi-scalar issue: its various aspects – noise, soil, odour, air, water et cetera – are influenced by processes at multiple spatial and temporal scales. Decisions

  11. Simple Solutions to Complex Problems: Moral Panic and the Fluid Shift from "Equity" to "Quality" in Education

    Science.gov (United States)

    Mockler, Nicole

    2014-01-01

    Education is increasingly conceptualised by governments and policymakers in western democracies in terms of productivity and human capital, emphasising elements of individualism and competition over concerns around democracy and equity. More and more, solutions to intransigent educational problems related to equity are seen in terms of quality and…

  12. The Use of Tracer Gas Measurements in Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Brohus, Henrik; Hyldgård, Carl-Erik

    A Danish town hall with substantial complaints of poor indoor air quality is examined. This paper describes ·the use of traGer gas measurements which form an important part in the detection and solution of the problems. Investigations are carried out both in the field and in the laboratory using...

  13. Heuristics for the economic dispatch problem

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Benjamin Carpio [Centro Nacional de Controle de Energia (CENACE), Mexico, D.F. (Mexico). Dept. de Planificacion Economica de Largo Plazo], E-mail: benjamin.carpo@cfe.gob.mx; Laureano Cruces, A L; Lopez Bracho, R; Ramirez Rodriguez, J. [Universidad Autonoma Metropolitana (UAM), Mexico, D.F. (Brazil). Dept. de Sistemas], Emails: clc@correo.azc.uam.mx, rlb@correo.azc.uam.mx, jararo@correo.azc.uam.mx

    2009-07-01

    This paper presents GRASP (Greedy Randomized Adaptive Search Procedure), Simulated Annealing (SAA), Genetic (GA), and Hybrid Genetic (HGA) Algorithms for the economic dispatch problem (EDP), considering non-convex cost functions and dead zones the only restrictions, showing the results obtained. We also present parameter settings that are specifically applicable to the EDP, and a comparative table of results for each heuristic. It is shown that these methods outperform the classical methods without the need to assume convexity of the target function. (author)

  14. Entrepreneurial Learning, Heuristics and Venture Creation

    OpenAIRE

    RAUF, MIAN SHAMS; ZAINULLAH, MOHAMMAD

    2009-01-01

    After rigorous criticism on trait approach and with the emergence of behavioral approach in entrepreneurship during 1980s, the researchers started to introduce learning and cognitive theories in entrepreneurship to describe and explain the dynamic nature of entrepreneurship. Many researchers have described venture creation as a core and the single most important element of entrepreneurship. This thesis will discuss and present the role of entrepreneurial learning and heuristics in venture cre...

  15. An Efficient Meta Heuristic Algorithm to Solve Economic Load Dispatch Problems

    Directory of Open Access Journals (Sweden)

    R Subramanian

    2013-12-01

    Full Text Available The Economic Load Dispatch (ELD problems in power generation systems are to reduce the fuel cost by reducing the total cost for the generation of electric power. This paper presents an efficient Modified Firefly Algorithm (MFA, for solving ELD Problem. The main objective of the problems is to minimize the total fuel cost of the generating units having quadratic cost functions subjected to limits on generator true power output and transmission losses. The MFA is a stochastic, Meta heuristic approach based on the idealized behaviour of the flashing characteristics of fireflies. This paper presents an application of MFA to ELD for six generator test case system. MFA is applied to ELD problem and compared its solution quality and computation efficiency to Genetic algorithm (GA, Differential Evolution (DE, Particle swarm optimization (PSO, Artificial Bee Colony optimization (ABC, Biogeography-Based Optimization (BBO, Bacterial Foraging optimization (BFO, Firefly Algorithm (FA techniques. The simulation result shows that the proposed algorithm outperforms previous optimization methods.

  16. The affect heuristic in occupational safety.

    Science.gov (United States)

    Savadori, Lucia; Caovilla, Jessica; Zaniboni, Sara; Fraccaroli, Franco

    2015-07-08

    The affect heuristic is a rule of thumb according to which, in the process of making a judgment or decision, people use affect as a cue. If a stimulus elicits positive affect then risks associated to that stimulus are viewed as low and benefits as high; conversely, if the stimulus elicits negative affect, then risks are perceived as high and benefits as low. The basic tenet of this study is that affect heuristic guides worker's judgment and decision making in a risk situation. The more the worker likes her/his organization the less she/he will perceive the risks as high. A sample of 115 employers and 65 employees working in small family agricultural businesses completed a questionnaire measuring perceived safety costs, psychological safety climate, affective commitment and safety compliance. A multi-sample structural analysis supported the thesis that safety compliance can be explained through an affect-based heuristic reasoning, but only for employers. Positive affective commitment towards their family business reduced employers' compliance with safety procedures by increasing the perceived cost of implementing them.

  17. When decision heuristics and science collide.

    Science.gov (United States)

    Yu, Erica C; Sprenger, Amber M; Thomas, Rick P; Dougherty, Michael R

    2014-04-01

    The ongoing discussion among scientists about null-hypothesis significance testing and Bayesian data analysis has led to speculation about the practices and consequences of "researcher degrees of freedom." This article advances this debate by asking the broader questions that we, as scientists, should be asking: How do scientists make decisions in the course of doing research, and what is the impact of these decisions on scientific conclusions? We asked practicing scientists to collect data in a simulated research environment, and our findings show that some scientists use data collection heuristics that deviate from prescribed methodology. Monte Carlo simulations show that data collection heuristics based on p values lead to biases in estimated effect sizes and Bayes factors and to increases in both false-positive and false-negative rates, depending on the specific heuristic. We also show that using Bayesian data collection methods does not eliminate these biases. Thus, our study highlights the little appreciated fact that the process of doing science is a behavioral endeavor that can bias statistical description and inference in a manner that transcends adherence to any particular statistical framework.

  18. The recognition heuristic: A decade of research

    Directory of Open Access Journals (Sweden)

    Gerd Gigerenzer

    2011-02-01

    Full Text Available The recognition heuristic exploits the basic psychological capacity for recognition in order to make inferences about unknown quantities in the world. In this article, we review and clarify issues that emerged from our initial work (Goldstein and Gigerenzer, 1999, 2002, including the distinction between a recognition and an evaluation process. There is now considerable evidence that (i the recognition heuristic predicts the inferences of a substantial proportion of individuals consistently, even in the presence of one or more contradicting cues, (ii people are adaptive decision makers in that accordance increases with larger recognition validity and decreases in situations when the validity is low or wholly indeterminable, and (iii in the presence of contradicting cues, some individuals appear to select different strategies. Little is known about these individual differences, or how to precisely model the alternative strategies. Although some researchers have attributed judgments inconsistent with the use of the recognition heuristic to compensatory processing, little research on such compensatory models has been reported. We discuss extensions of the recognition model, open questions, unanticipated results, and the surprising predictive power of recognition in forecasting.

  19. "The Gaze Heuristic:" Biography of an Adaptively Rational Decision Process.

    Science.gov (United States)

    Hamlin, Robert P

    2017-04-01

    This article is a case study that describes the natural and human history of the gaze heuristic. The gaze heuristic is an interception heuristic that utilizes a single input (deviation from a constant angle of approach) repeatedly as a task is performed. Its architecture, advantages, and limitations are described in detail. A history of the gaze heuristic is then presented. In natural history, the gaze heuristic is the only known technique used by predators to intercept prey. In human history the gaze heuristic was discovered accidentally by Royal Air Force (RAF) fighter command just prior to World War II. As it was never discovered by the Luftwaffe, the technique conferred a decisive advantage upon the RAF throughout the war. After the end of the war in America, German technology was combined with the British heuristic to create the Sidewinder AIM9 missile, the most successful autonomous weapon ever built. There are no plans to withdraw it or replace its guiding gaze heuristic. The case study demonstrates that the gaze heuristic is a specific heuristic type that takes a single best input at the best time (take the best 2 ). Its use is an adaptively rational response to specific, rapidly evolving decision environments that has allowed those animals/humans/machines who use it to survive, prosper, and multiply relative to those who do not. Copyright © 2017 Cognitive Science Society, Inc.

  20. A new unconditionally stable and consistent quasi-analytical in-stream water quality solution scheme for CSTR-based water quality simulators

    Science.gov (United States)

    Woldegiorgis, Befekadu Taddesse; van Griensven, Ann; Pereira, Fernando; Bauwens, Willy

    2017-06-01

    Most common numerical solutions used in CSTR-based in-stream water quality simulators are susceptible to instabilities and/or solution inconsistencies. Usually, they cope with instability problems by adopting computationally expensive small time steps. However, some simulators use fixed computation time steps and hence do not have the flexibility to do so. This paper presents a novel quasi-analytical solution for CSTR-based water quality simulators of an unsteady system. The robustness of the new method is compared with the commonly used fourth-order Runge-Kutta methods, the Euler method and three versions of the SWAT model (SWAT2012, SWAT-TCEQ, and ESWAT). The performance of each method is tested for different hypothetical experiments. Besides the hypothetical data, a real case study is used for comparison. The growth factors we derived as stability measures for the different methods and the R-factor—considered as a consistency measure—turned out to be very useful for determining the most robust method. The new method outperformed all the numerical methods used in the hypothetical comparisons. The application for the Zenne River (Belgium) shows that the new method provides stable and consistent BOD simulations whereas the SWAT2012 model is shown to be unstable for the standard daily computation time step. The new method unconditionally simulates robust solutions. Therefore, it is a reliable scheme for CSTR-based water quality simulators that use first-order reaction formulations.

  1. Penjadwalan Produksi Garment Menggunakan Algoritma Heuristic Pour

    Directory of Open Access Journals (Sweden)

    Rizal Rachman

    2018-04-01

    Full Text Available Abstrak Penjadwalan merupakan suatu kegiatan pengalokasian sumber daya yang terbatas untuk mengerjakan sejumlah pekerjaan. Proses penjadwalan timbul jika terdapat keterbatasan sumber daya yang dimiliki, karena pada saat ini perusahaan menerapkan sistem penjadwalan manual dimana dengan penjadwalan tersebut masih terdapat beberapa produk yang terlewati sehingga menyebabkan keterlambatan dalam proses produksi, aturan ini sering tidak menguntungkan bagi order yang membutuhkan waktu proses pendek karena apabila order itu berada dibelakang antrian maka harus menunggu lama sebelum diproses dan menyebabkan waktu penyelesaian seluruh order menjadi panjang, sehingga diperlukan adanya pengaturan sumber-sumber daya yang ada secara efisien. Adapun dasar perhitungan Penjadwalan dengan menggunakan algoritma Heuristic Pour. Tahapan-tahapan penelitian terdiri dari pengumpulan data, perhitungan waktu standar, perhitungan total waktu proses berdasarkan job, penjadwalan dengan metode awal perusahaan, penjadwalan dengan metode Heuristik Pour. Berdasarkan hasil penjadwalan menggunakan Heuristik Pour diperoleh penghematan dibanding dengan metode perusahaan saat ini, sehingga dapat digunakan sebagai alternatif metode dalam melakukan penjadwalan pengerjaan proses produksi di perusahaan Garment tersebut. Kata kunci: Penjadwalan Produksi, Algoritma, Heuristic Pour. Abstract Scheduling is a limited resource allocation activity to do a number of jobs. The scheduling process arises if there are limited resources available, because at this time the company implement a manual scheduling system where the scheduling is still there are some products passed so as to cause delays in the production process, this rule is often not profitable for orders that require short processing time because if the order is behind the queue then it must wait a long time before it is processed and cause the completion time of all orders to be long, so it is necessary to regulate the existing

  2. Analysis of the iteratively regularized Gauss-Newton method under a heuristic rule

    Science.gov (United States)

    Jin, Qinian; Wang, Wei

    2018-03-01

    The iteratively regularized Gauss-Newton method is one of the most prominent regularization methods for solving nonlinear ill-posed inverse problems when the data is corrupted by noise. In order to produce a useful approximate solution, this iterative method should be terminated properly. The existing a priori and a posteriori stopping rules require accurate information on the noise level, which may not be available or reliable in practical applications. In this paper we propose a heuristic selection rule for this regularization method, which requires no information on the noise level. By imposing certain conditions on the noise, we derive a posteriori error estimates on the approximate solutions under various source conditions. Furthermore, we establish a convergence result without using any source condition. Numerical results are presented to illustrate the performance of our heuristic selection rule.

  3. Heuristic and Exact Algorithms for the Two-Machine Just in Time Job Shop Scheduling Problem

    Directory of Open Access Journals (Sweden)

    Mohammed Al-Salem

    2016-01-01

    Full Text Available The problem addressed in this paper is the two-machine job shop scheduling problem when the objective is to minimize the total earliness and tardiness from a common due date (CDD for a set of jobs when their weights equal 1 (unweighted problem. This objective became very significant after the introduction of the Just in Time manufacturing approach. A procedure to determine whether the CDD is restricted or unrestricted is developed and a semirestricted CDD is defined. Algorithms are introduced to find the optimal solution when the CDD is unrestricted and semirestricted. When the CDD is restricted, which is a much harder problem, a heuristic algorithm is proposed to find approximate solutions. Through computational experiments, the heuristic algorithms’ performance is evaluated with problems up to 500 jobs.

  4. High Quality, Low Cost Bulk Gallium Nitride Substrates Grown by the Electrochemical Solution Growth Method

    Energy Technology Data Exchange (ETDEWEB)

    Seacrist, Michael [SunEdison Inc., St. Peters, MO (United States)

    2017-08-15

    The objective of this project was to develop the Electrochemical Solution Growth (ESG) method conceived / patented at Sandia National Laboratory into a commercially viable bulk gallium nitride (GaN) growth process that can be scaled to low cost, high quality, and large area GaN wafer substrate manufacturing. The goal was to advance the ESG growth technology by demonstrating rotating seed growth at the lab scale and then transitioning process to prototype commercial system, while validating the GaN material and electronic / optical device quality. The desired outcome of the project is a prototype commercial process for US-based manufacturing of high quality, large area, and lower cost GaN substrates that can drive widespread deployment of energy efficient GaN-based power electronic and optical devices. In year 1 of the project (Sept 2012 – Dec 2013) the overall objective was to demonstrate crystalline GaN growth > 100um on a GaN seed crystal. The development plan included tasks to demonstrate and implement a method for purifying reagent grade salts, develop the reactor 1 process for rotating seed Electrochemical Solution Growth (ESG) of GaN, grow and characterize ESG GaN films, develop a fluid flow and reaction chemistry model for GaN film growth, and design / build an improved growth reactor capable of scaling to 50mm seed diameter. The first year’s project objectives were met in some task areas including salt purification, film characterization, modeling, and reactor 2 design / fabrication. However, the key project objective of the growth of a crystalline GaN film on the seed template was not achieved. Amorphous film growth on the order of a few tenths of a micron has been detected with a film composition including Ga and N, plus several other impurities originating from the process solution and hardware. The presence of these impurities, particularly the oxygen, has inhibited the demonstration of crystalline GaN film growth on the seed template. However, the

  5. A Modularity Degree Based Heuristic Community Detection Algorithm

    Directory of Open Access Journals (Sweden)

    Dongming Chen

    2014-01-01

    Full Text Available A community in a complex network can be seen as a subgroup of nodes that are densely connected. Discovery of community structures is a basic problem of research and can be used in various areas, such as biology, computer science, and sociology. Existing community detection methods usually try to expand or collapse the nodes partitions in order to optimize a given quality function. These optimization function based methods share the same drawback of inefficiency. Here we propose a heuristic algorithm (MDBH algorithm based on network structure which employs modularity degree as a measure function. Experiments on both synthetic benchmarks and real-world networks show that our algorithm gives competitive accuracy with previous modularity optimization methods, even though it has less computational complexity. Furthermore, due to the use of modularity degree, our algorithm naturally improves the resolution limit in community detection.

  6. A derived heuristics based multi-objective optimization procedure for micro-grid scheduling

    Science.gov (United States)

    Li, Xin; Deb, Kalyanmoy; Fang, Yanjun

    2017-06-01

    With the availability of different types of power generators to be used in an electric micro-grid system, their operation scheduling as the load demand changes with time becomes an important task. Besides satisfying load balance constraints and the generator's rated power, several other practicalities, such as limited availability of grid power and restricted ramping of power output from generators, must all be considered during the operation scheduling process, which makes it difficult to decide whether the optimization results are accurate and satisfactory. In solving such complex practical problems, heuristics-based customized optimization algorithms are suggested. However, due to nonlinear and complex interactions of variables, it is difficult to come up with heuristics in such problems off-hand. In this article, a two-step strategy is proposed in which the first task deciphers important heuristics about the problem and the second task utilizes the derived heuristics to solve the original problem in a computationally fast manner. Specifically, the specific operation scheduling is considered from a two-objective (cost and emission) point of view. The first task develops basic and advanced level knowledge bases offline from a series of prior demand-wise optimization runs and then the second task utilizes them to modify optimized solutions in an application scenario. Results on island and grid connected modes and several pragmatic formulations of the micro-grid operation scheduling problem clearly indicate the merit of the proposed two-step procedure.

  7. Treatment planning for prostate brachytherapy using region of interest adjoint functions and a greedy heuristic

    International Nuclear Information System (INIS)

    Yoo, Sua; Kowalok, Michael E; Thomadsen, Bruce R; Henderson, Douglass L

    2003-01-01

    We have developed an efficient treatment-planning algorithm for prostate implants that is based on region of interest (ROI) adjoint functions and a greedy heuristic. For this work, we define the adjoint function for an ROI as the sensitivity of the average dose in the ROI to a unit-strength brachytherapy source at any seed position. The greedy heuristic uses a ratio of target and critical structure adjoint functions to rank seed positions according to their ability to irradiate the target ROI while sparing critical structure ROIs. This ratio is computed once for each seed position prior to the optimization process. Optimization is performed by a greedy heuristic that selects seed positions according to their ratio values. With this method, clinically acceptable treatment plans are obtained in less than 2 s. For comparison, a branch-and-bound method to solve a mixed integer-programming model took more than 50 min to arrive at a feasible solution. Both methods achieved good treatment plans, but the speedup provided by the greedy heuristic was a factor of approximately 1500. This attribute makes this algorithm suitable for intra-operative real-time treatment planning

  8. Cultural heuristics in risk assessment of HIV/AIDS.

    Science.gov (United States)

    Bailey, Ajay; Hutter, Inge

    2006-01-01

    Behaviour change models in HIV prevention tend to consider that risky sexual behaviours reflect risk assessments and that by changing risk assessments behaviour can be changed. Risk assessment is however culturally constructed. Individuals use heuristics or bounded cognitive devices derived from broader cultural meaning systems to rationalize uncertainty. In this study, we identify some of the cultural heuristics used by migrant men in Goa, India to assess their risk of HIV infection from different sexual partners. Data derives from a series of in-depth interviews and a locally informed survey. Cultural heuristics identified include visual heuristics, heuristics of gender roles, vigilance and trust. The paper argues that, for more culturally informed HIV/AIDS behaviour change interventions, knowledge of cultural heuristics is essential.

  9. A HYBRID HEURISTIC ALGORITHM FOR THE CLUSTERED TRAVELING SALESMAN PROBLEM

    Directory of Open Access Journals (Sweden)

    Mário Mestria

    2016-04-01

    Full Text Available ABSTRACT This paper proposes a hybrid heuristic algorithm, based on the metaheuristics Greedy Randomized Adaptive Search Procedure, Iterated Local Search and Variable Neighborhood Descent, to solve the Clustered Traveling Salesman Problem (CTSP. Hybrid Heuristic algorithm uses several variable neighborhood structures combining the intensification (using local search operators and diversification (constructive heuristic and perturbation routine. In the CTSP, the vertices are partitioned into clusters and all vertices of each cluster have to be visited contiguously. The CTSP is -hard since it includes the well-known Traveling Salesman Problem (TSP as a special case. Our hybrid heuristic is compared with three heuristics from the literature and an exact method. Computational experiments are reported for different classes of instances. Experimental results show that the proposed hybrid heuristic obtains competitive results within reasonable computational time.

  10. Evolutionary algorithm based heuristic scheme for nonlinear heat transfer equations.

    Science.gov (United States)

    Ullah, Azmat; Malik, Suheel Abdullah; Alimgeer, Khurram Saleem

    2018-01-01

    In this paper, a hybrid heuristic scheme based on two different basis functions i.e. Log Sigmoid and Bernstein Polynomial with unknown parameters is used for solving the nonlinear heat transfer equations efficiently. The proposed technique transforms the given nonlinear ordinary differential equation into an equivalent global error minimization problem. Trial solution for the given nonlinear differential equation is formulated using a fitness function with unknown parameters. The proposed hybrid scheme of Genetic Algorithm (GA) with Interior Point Algorithm (IPA) is opted to solve the minimization problem and to achieve the optimal values of unknown parameters. The effectiveness of the proposed scheme is validated by solving nonlinear heat transfer equations. The results obtained by the proposed scheme are compared and found in sharp agreement with both the exact solution and solution obtained by Haar Wavelet-Quasilinearization technique which witnesses the effectiveness and viability of the suggested scheme. Moreover, the statistical analysis is also conducted for investigating the stability and reliability of the presented scheme.

  11. A proposed heuristic methodology for searching reloading pattern

    International Nuclear Information System (INIS)

    Choi, K. Y.; Yoon, Y. K.

    1993-01-01

    A new heuristic method for loading pattern search has been developed to overcome shortcomings of the algorithmic approach. To reduce the size of vast solution space, general shuffling rules, a regionwise shuffling method, and a pattern grouping method were introduced. The entropy theory was applied to classify possible loading patterns into groups with similarity between them. The pattern search program was implemented with use of the PROLOG language. A two-group nodal code MEDIUM-2D was used for analysis of power distribution in the core. The above mentioned methodology has been tested to show effectiveness in reducing of solution space down to a few hundred pattern groups. Burnable poison rods were then arranged in each pattern group in accordance with burnable poison distribution rules, which led to further reduction of the solution space to several scores of acceptable pattern groups. The method of maximizing cycle length (MCL) and minimizing power-peaking factor (MPF) were applied to search for specific useful loading patterns from the acceptable pattern groups. Thus, several specific loading patterns that have low power-peaking factor and large cycle length were successfully searched from the selected pattern groups. (Author)

  12. Evolutionary algorithm based heuristic scheme for nonlinear heat transfer equations.

    Directory of Open Access Journals (Sweden)

    Azmat Ullah

    Full Text Available In this paper, a hybrid heuristic scheme based on two different basis functions i.e. Log Sigmoid and Bernstein Polynomial with unknown parameters is used for solving the nonlinear heat transfer equations efficiently. The proposed technique transforms the given nonlinear ordinary differential equation into an equivalent global error minimization problem. Trial solution for the given nonlinear differential equation is formulated using a fitness function with unknown parameters. The proposed hybrid scheme of Genetic Algorithm (GA with Interior Point Algorithm (IPA is opted to solve the minimization problem and to achieve the optimal values of unknown parameters. The effectiveness of the proposed scheme is validated by solving nonlinear heat transfer equations. The results obtained by the proposed scheme are compared and found in sharp agreement with both the exact solution and solution obtained by Haar Wavelet-Quasilinearization technique which witnesses the effectiveness and viability of the suggested scheme. Moreover, the statistical analysis is also conducted for investigating the stability and reliability of the presented scheme.

  13. A hybridised variable neighbourhood tabu search heuristic to increase security in a utility network

    International Nuclear Information System (INIS)

    Janssens, Jochen; Talarico, Luca; Sörensen, Kenneth

    2016-01-01

    We propose a decision model aimed at increasing security in a utility network (e.g., electricity, gas, water or communication network). The network is modelled as a graph, the edges of which are unreliable. We assume that all edges (e.g., pipes, cables) have a certain, not necessarily equal, probability of failure, which can be reduced by selecting edge-specific security strategies. We develop a mathematical programming model and a metaheuristic approach that uses a greedy random adaptive search procedure to find an initial solution and uses tabu search hybridised with iterated local search and a variable neighbourhood descend heuristic to improve this solution. The main goal is to reduce the risk of service failure between an origin and a destination node by selecting the right combination of security measures for each network edge given a limited security budget. - Highlights: • A decision model aimed at increasing security in a utility network is proposed. • The goal is to reduce the risk of service failure given a limited security budget. • An exact approach and a variable neighbourhood tabu search heuristic are developed. • A generator for realistic networks is built and used to test the solution methods. • The hybridised heuristic reduces the total risk on average with 32%.

  14. Hydro-Thermal-Wind Generation Scheduling Considering Economic and Environmental Factors Using Heuristic Algorithms

    Directory of Open Access Journals (Sweden)

    Suresh K. Damodaran

    2018-02-01

    Full Text Available Hydro-thermal-wind generation scheduling (HTWGS with economic and environmental factors is a multi-objective complex nonlinear power system optimization problem with many equality and inequality constraints. The objective of the problem is to generate an hour-by-hour optimum schedule of hydro-thermal-wind power plants to attain the least emission of pollutants from thermal plants and a reduced generation cost of thermal and wind plants for a 24-h period, satisfying the system constraints. The paper presents a detailed framework of the HTWGS problem and proposes a modified particle swarm optimization (MPSO algorithm for evolving a solution. The competency of selected heuristic algorithms, representing different heuristic groups, viz. the binary coded genetic algorithm (BCGA, particle swarm optimization (PSO, improved harmony search (IHS, and JAYA algorithm, for searching for an optimal solution to HTWGS considering economic and environmental factors was investigated in a trial system consisting of a multi-stream cascaded system with four reservoirs, three thermal plants, and two wind plants. Appropriate mathematical models were used for representing the water discharge, generation cost, and pollutant emission of respective power plants incorporated in the system. Statistical analysis was performed to check the consistency and reliability of the proposed algorithm. The simulation results indicated that the proposed MPSO algorithm provided a better solution to the problem of HTWGS, with a reduced generation cost and the least emission, when compared with the other heuristic algorithms considered.

  15. Quality assessment of Isfahan Medical Faculty web site electronic services and prioritizing solutions using analytic hierarchy process approach.

    Science.gov (United States)

    Hajrahimi, Nafiseh; Dehaghani, Sayed Mehdi Hejazi; Hajrahimi, Nargess; Sarmadi, Sima

    2014-01-01

    Implementing information technology in the best possible way can bring many advantages such as applying electronic services and facilitating tasks. Therefore, assessment of service providing systems is a way to improve the quality and elevate these systems including e-commerce, e-government, e-banking, and e-learning. This study was aimed to evaluate the electronic services in the website of Isfahan University of Medical Sciences in order to propose solutions to improve them. Furthermore, we aim to rank the solutions based on the factors that enhance the quality of electronic services by using analytic hierarchy process (AHP) method. Non-parametric test was used to assess the quality of electronic services. The assessment of propositions was based on Aqual model and they were prioritized using AHP approach. The AHP approach was used because it directly applies experts' deductions in the model, and lead to more objective results in the analysis and prioritizing the risks. After evaluating the quality of the electronic services, a multi-criteria decision making frame-work was used to prioritize the proposed solutions. Non-parametric tests and AHP approach using Expert Choice software. The results showed that students were satisfied in most of the indicators. Only a few indicators received low satisfaction from students including, design attractiveness, the amount of explanation and details of information, honesty and responsiveness of authorities, and the role of e-services in the user's relationship with university. After interviewing with Information and Communications Technology (ICT) experts at the university, measurement criteria, and solutions to improve the quality were collected. The best solutions were selected by EC software. According to the results, the solution "controlling and improving the process in handling users complaints" is of the utmost importance and authorities have to have it on the website and place great importance on updating this process

  16. Quality assessment of Isfahan Medical Faculty web site electronic services and prioritizing solutions using analytic hierarchy process approach

    Science.gov (United States)

    Hajrahimi, Nafiseh; Dehaghani, Sayed Mehdi Hejazi; Hajrahimi, Nargess; Sarmadi, Sima

    2014-01-01

    Context: Implementing information technology in the best possible way can bring many advantages such as applying electronic services and facilitating tasks. Therefore, assessment of service providing systems is a way to improve the quality and elevate these systems including e-commerce, e-government, e-banking, and e-learning. Aims: This study was aimed to evaluate the electronic services in the website of Isfahan University of Medical Sciences in order to propose solutions to improve them. Furthermore, we aim to rank the solutions based on the factors that enhance the quality of electronic services by using analytic hierarchy process (AHP) method. Materials and Methods: Non-parametric test was used to assess the quality of electronic services. The assessment of propositions was based on Aqual model and they were prioritized using AHP approach. The AHP approach was used because it directly applies experts’ deductions in the model, and lead to more objective results in the analysis and prioritizing the risks. After evaluating the quality of the electronic services, a multi-criteria decision making frame-work was used to prioritize the proposed solutions. Statistical Analysis Used: Non-parametric tests and AHP approach using Expert Choice software. Results: The results showed that students were satisfied in most of the indicators. Only a few indicators received low satisfaction from students including, design attractiveness, the amount of explanation and details of information, honesty and responsiveness of authorities, and the role of e-services in the user's relationship with university. After interviewing with Information and Communications Technology (ICT) experts at the university, measurement criteria, and solutions to improve the quality were collected. The best solutions were selected by EC software. According to the results, the solution “controlling and improving the process in handling users complaints” is of the utmost importance and authorities

  17. Identifying Onboarding Heuristics for Free-to-Play Mobile Games

    DEFF Research Database (Denmark)

    Thomsen, Line Ebdrup; Weigert Petersen, Falko; Drachen, Anders

    2016-01-01

    a set of heuristics for the design of onboarding phases in mobile games is presented. The heuristics are identified by a lab-based mixed-methods experiment, utilizing lightweight psycho-physiological measures together with self-reported player responses, across three titles that cross the genres...... of puzzle games, base builders and arcade games, and utilize different onboarding phase design approaches. Results showcase how heuristics can be used to design engaging onboarding phases in mobile games....

  18. The recognition heuristic : A review of theory and tests

    OpenAIRE

    Pachur, T.; Todd, P.; Gigerenzer, G.; Schooler, L.; Goldstein, D.

    2011-01-01

    The recognition heuristic is a prime example of how, by exploiting a match between mind and environment, a simple mental strategy can lead to efficient decision making. The proposal of the heuristic initiated a debate about the processes underlying the use of recognition in decision making. We review research addressing four key aspects of the recognition heuristic: (a) that recognition is often an ecologically valid cue; (b) that people often follow recognition when making inferences; (c) th...

  19. A heuristic evaluation of the Facebook's advertising tool beacon

    OpenAIRE

    Jamal, A; Cole, M

    2009-01-01

    Interface usability is critical to the successful adoption of information systems. The aim of this study is to evaluate interface of Facebook's advertising tool Beacon by using privacy heuristics [4]. Beacon represents an interesting case study because of the negative media and user backlash it received. The findings of heuristic evaluation suggest violation of privacy heuristics [4]. Here, analysis identified concerns about user choice and consent, integrity and security of data, and awarene...

  20. Interliminal Design: Understanding cognitive heuristics to mitigate design distortion

    OpenAIRE

    Andrew McCollough; DeAunne Denmark; Donald Harker

    2014-01-01

    Cognitive heuristics are mental shortcuts adapted over time to enable rapid interpretation of our complex environment. They are intrinsic to human cognition and resist modification. Heuristics applied outside the context to which they are best suited are termed cognitive bias, and are the cause of systematic errors in judgment and reasoning. As both a cognitive and intuitive discipline, design by individuals is vulnerable to context-inappropriate heuristic usage. Designing in groups can act p...

  1. State analysis of BOP using statistical and heuristic methods

    International Nuclear Information System (INIS)

    Heo, Gyun Young; Chang, Soon Heung

    2003-01-01

    Under the deregulation environment, the performance enhancement of BOP in nuclear power plants is being highlighted. To analyze performance level of BOP, we use the performance test procedures provided from an authorized institution such as ASME. However, through plant investigation, it was proved that the requirements of the performance test procedures about the reliability and quantity of sensors was difficult to be satisfied. As a solution of this, state analysis method that are the expanded concept of signal validation, was proposed on the basis of the statistical and heuristic approaches. Authors recommended the statistical linear regression model by analyzing correlation among BOP parameters as a reference state analysis method. Its advantage is that its derivation is not heuristic, it is possible to calculate model uncertainty, and it is easy to apply to an actual plant. The error of the statistical linear regression model is below 3% under normal as well as abnormal system states. Additionally a neural network model was recommended since the statistical model is impossible to apply to the validation of all of the sensors and is sensitive to the outlier that is the signal located out of a statistical distribution. Because there are a lot of sensors need to be validated in BOP, wavelet analysis (WA) were applied as a pre-processor for the reduction of input dimension and for the enhancement of training accuracy. The outlier localization capability of WA enhanced the robustness of the neural network. The trained neural network restored the degraded signals to the values within ±3% of the true signals

  2. IMPACT OF HEURISTIC STRATEGIES ON PUPILS’ ATTITUDES TO PROBLEM SOLVING

    Directory of Open Access Journals (Sweden)

    NOVOTNÁ, Jarmila

    2015-03-01

    Full Text Available The paper is a sequel to the article (Novotná et al., 2014, where the authors present the results of a 4-month experiment whose main aim was to change pupils’ culture of problem solving by using heuristic strategies suitable for problem solving in mathematics education. (Novotná et al., 2014 focused on strategies Analogy, Guess – check – revise, Systematic experimentation, Problem reformulation, Solution drawing, Working backwards and Use of graphs of functions. This paper focuses on two other heuristic strategies convenient for improvement of pupils’ culture of problem solving: Introduction of an auxiliary element and Omitting a condition. In the first part, the strategies Guess – Check – Revise, Working backwards, Introduction of an auxiliary element and Omitting a condition are characterized in detail and illustrated by examples of their use in order to capture their characteristics. In the second part we focus on the newly introduced strategies and analyse work with them in lessons using the tools from (Novotná et al., 2014. The analysis of results of the experiment indicates that, unlike in case of the strategy Introduction of an auxiliary element, successful use of the strategy Omitting a condition requires longer teacher’s work with the pupils. The following analysis works with the strategy Systematic experimentation, which seemed to be the easiest to master in (Novotná et al., 2014; we focus on the dangers it bears when it is used by pupils. The conclusion from (Novotná et al., 2014, which showed that if pupils are introduced to an environment that supports their creativity, their attitude towards problem solving changes in a positive way already after the period of four months, is confirmed.

  3. Heuristic Portfolio Trading Rules with Capital Gain Taxes

    DEFF Research Database (Denmark)

    Fischer, Marcel; Gallmeyer, Michael

    in some cases. Overlaying simple tax trading heuristics on these trading strategies improves out-of-sample performance. In particular, the 1/N trading strategy's welfare gains improve when a variety of tax trading heuristics are also imposed. For medium to large transaction costs, no trading strategy can...... outperform a 1/N trading strategy augmented with a tax heuristic, not even the most tax- and transaction-cost efficient buy-and-hold strategy. Overall, the best strategy is 1/N augmented with a heuristic that allows for a fixed deviation in absolute portfolio weights. Our results show that the best trading...

  4. Intelligent process mapping through systematic improvement of heuristics

    Science.gov (United States)

    Ieumwananonthachai, Arthur; Aizawa, Akiko N.; Schwartz, Steven R.; Wah, Benjamin W.; Yan, Jerry C.

    1992-01-01

    The present system for automatic learning/evaluation of novel heuristic methods applicable to the mapping of communication-process sets on a computer network has its basis in the testing of a population of competing heuristic methods within a fixed time-constraint. The TEACHER 4.1 prototype learning system implemented or learning new postgame analysis heuristic methods iteratively generates and refines the mappings of a set of communicating processes on a computer network. A systematic exploration of the space of possible heuristic methods is shown to promise significant improvement.

  5. Recycling of osmotic solutions in microwave-osmotic dehydration: product quality and potential for creation of a novel product.

    Science.gov (United States)

    Wray, Derek; Ramaswamy, Hosahalli S

    2016-08-01

    Despite osmotic dehydration being a cost effective process for moisture removal, the cost implications of making, regenerating, and properly disposing of the spent osmotic solutions contributes greatly to the economic feasibility of the drying operation. The potential for recycling of osmotic solutions and their use for creation of a novel product was explored using microwave-osmotic dehydration under continuous flow spray (MWODS) conditions. Identical runs were repeated 10 times to determine the progressive physical and compositional effects of the thermal treatment and leaching from the cranberry samples. The microbiological stability and constant drying performance indicated that MWODS would be well suited for employing recycled solutions. While the anthocyanin content of the solution never approached that of cranberry juice concentrate, it is demonstrated that the spent syrup can infuse these health positive components into another product (apple). This study found that re-using osmotic solutions is a viable option to reduce cost in future MWODS applications, with no detriment to product quality and potential to use the spent solution for novel products. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  6. A Novel Spatial-Temporal Voronoi Diagram-Based Heuristic Approach for Large-Scale Vehicle Routing Optimization with Time Constraints

    Directory of Open Access Journals (Sweden)

    Wei Tu

    2015-10-01

    Full Text Available Vehicle routing optimization (VRO designs the best routes to reduce travel cost, energy consumption, and carbon emission. Due to non-deterministic polynomial-time hard (NP-hard complexity, many VROs involved in real-world applications require too much computing effort. Shortening computing time for VRO is a great challenge for state-of-the-art spatial optimization algorithms. From a spatial-temporal perspective, this paper presents a spatial-temporal Voronoi diagram-based heuristic approach for large-scale vehicle routing problems with time windows (VRPTW. Considering time constraints, a spatial-temporal Voronoi distance is derived from the spatial-temporal Voronoi diagram to find near neighbors in the space-time searching context. A Voronoi distance decay strategy that integrates a time warp operation is proposed to accelerate local search procedures. A spatial-temporal feature-guided search is developed to improve unpromising micro route structures. Experiments on VRPTW benchmarks and real-world instances are conducted to verify performance. The results demonstrate that the proposed approach is competitive with state-of-the-art heuristics and achieves high-quality solutions for large-scale instances of VRPTWs in a short time. This novel approach will contribute to spatial decision support community by developing an effective vehicle routing optimization method for large transportation applications in both public and private sectors.

  7. Vervet monkeys use paths consistent with context-specific spatial movement heuristics.

    Science.gov (United States)

    Teichroeb, Julie A

    2015-10-01

    Animal foraging routes are analogous to the computationally demanding "traveling salesman problem" (TSP), where individuals must find the shortest path among several locations before returning to the start. Humans approximate solutions to TSPs using simple heuristics or "rules of thumb," but our knowledge of how other animals solve multidestination routing problems is incomplete. Most nonhuman primate species have shown limited ability to route plan. However, captive vervets were shown to solve a TSP for six sites. These results were consistent with either planning three steps ahead or a risk-avoidance strategy. I investigated how wild vervet monkeys (Chlorocebus pygerythrus) solved a path problem with six, equally rewarding food sites; where site arrangement allowed assessment of whether vervets found the shortest route and/or used paths consistent with one of three simple heuristics to navigate. Single vervets took the shortest possible path in fewer than half of the trials, usually in ways consistent with the most efficient heuristic (the convex hull). When in competition, vervets' paths were consistent with different, more efficient heuristics dependent on their dominance rank (a cluster strategy for dominants and the nearest neighbor rule for subordinates). These results suggest that, like humans, vervets may solve multidestination routing problems by applying simple, adaptive, context-specific "rules of thumb." The heuristics that were consistent with vervet paths in this study are the same as some of those asserted to be used by humans. These spatial movement strategies may have common evolutionary roots and be part of a universal mental navigational toolkit. Alternatively, they may have emerged through convergent evolution as the optimal way to solve multidestination routing problems.

  8. Using heuristic search for optimizing maintenance plans

    International Nuclear Information System (INIS)

    Mutanen, Teemu

    2012-01-01

    This work addresses the maintenance action selection process. Maintenance personnel need to evaluate maintenance actions and costs to keep the machines in working condition. Group of actions are evaluated together as maintenance plans. The maintenance plans as output provide information to the user about which actions to take if any and what future actions should be prepared for. The heuristic search method is implemented as part of general use toolbox for analysis of measurements from movable work machines. Impacts from machine's usage restrictions and maintenance activities are analysed. The results show that once put on a temporal perspective, the prioritized order of the actions is different and provide additional information to the user.

  9. Advances in heuristic signal processing and applications

    CERN Document Server

    Chatterjee, Amitava; Siarry, Patrick

    2013-01-01

    There have been significant developments in the design and application of algorithms for both one-dimensional signal processing and multidimensional signal processing, namely image and video processing, with the recent focus changing from a step-by-step procedure of designing the algorithm first and following up with in-depth analysis and performance improvement to instead applying heuristic-based methods to solve signal-processing problems. In this book the contributing authors demonstrate both general-purpose algorithms and those aimed at solving specialized application problems, with a spec

  10. Heuristics for the Robust Coloring Problem

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Gutiérrez Andrade

    2011-03-01

    Full Text Available Let $G$ and $\\bar{G}$ be complementary graphs. Given a penalty function defined on the edges of $G$, we will say that the rigidity of a $k$-coloring of $G$ is the sum of the penalties of the edges of G joining vertices of the same color. Based on the previous definition, the Robust Coloring Problem (RCP is stated as the search of the minimum rigidity $k$-coloring. In this work a comparison of heuristics based on simulated annealing, GRASP and scatter search is presented. These are the best results for the RCP that have been obtained.

  11. Further heuristics for $k$-means: The merge-and-split heuristic and the $(k,l)$-means

    OpenAIRE

    Nielsen, Frank; Nock, Richard

    2014-01-01

    Finding the optimal $k$-means clustering is NP-hard in general and many heuristics have been designed for minimizing monotonically the $k$-means objective. We first show how to extend Lloyd's batched relocation heuristic and Hartigan's single-point relocation heuristic to take into account empty-cluster and single-point cluster events, respectively. Those events tend to increasingly occur when $k$ or $d$ increases, or when performing several restarts. First, we show that those special events ...

  12. Coherent efforts in relation to COPD patients with special emphasis on the quality and technological solutions

    DEFF Research Database (Denmark)

    Bagger, Bettan; Vestergaard*, Kitt; Andresen, Mette

    Keywords: COPD, quality, clinical pathways, daily life, competences, welfare technology Background: Focus in Health Service moves towards quality and hence focus is on results that create quality in healthcare services. Technologies are assumed to promote more consistent quality in health care......, Hospital Naestved investigate COPD patients’ and health professionals’ perspectives with respect to their assessments of quality in clinical pathways and daily life focusing on clinical pathways, interdisciplinary sharing of knowledge and use of technology. Identification of parameters will be important...... recruits informants. Methodology: qualitative in depth interviews A literature review has been done to identify COPD patients and health professionals’ assessment of parameters for quality in clinical pathways and daily life. The study is a phenomenological explorative study focusing upon the meaning...

  13. Quality assessment of Isfahan Medical Faculty web site electronic services and prioritizing solutions using analytic hierarchy process approach

    OpenAIRE

    Hajrahimi, Nafiseh; Dehaghani, Sayed Mehdi Hejazi; Hajrahimi, Nargess; Sarmadi, Sima

    2014-01-01

    Context: Implementing information technology in the best possible way can bring many advantages such as applying electronic services and facilitating tasks. Therefore, assessment of service providing systems is a way to improve the quality and elevate these systems including e-commerce, e-government, e-banking, and e-learning. Aims: This study was aimed to evaluate the electronic services in the website of Isfahan University of Medical Sciences in order to propose solutions to improve them. F...

  14. Real-World Solutions for Developing High-Quality PHP Frameworks and Applications

    CERN Document Server

    Bergmann, Sebastian

    2011-01-01

    Learn to develop high-quality applications and frameworks in PHP Packed with in-depth information and step-by-step guidance, this book escorts you through the process of creating, maintaining and extending sustainable software of high quality with PHP. World-renowned PHP experts present real-world case studies for developing high-quality applications and frameworks in PHP that can easily be adapted to changing business requirements. . They offer different approaches to solving  typical development and quality assurance problems that every developer needs to know and master.Details the process

  15. Case-Based Reasoning as a Heuristic Selector in a Hyper-Heuristic for Course Timetabling Problems

    OpenAIRE

    Petrovic, Sanja; Qu, Rong

    2002-01-01

    This paper studies Knowledge Discovery (KD) using Tabu Search and Hill Climbing within Case-Based Reasoning (CBR) as a hyper-heuristic method for course timetabling problems. The aim of the hyper-heuristic is to choose the best heuristic(s) for given timetabling problems according to the knowledge stored in the case base. KD in CBR is a 2-stage iterative process on both case representation and the case base. Experimental results are analysed and related research issues for future work are dis...

  16. Influence of a Phospho-Potassic fertilizer solution on yield and quality of Wheat Crops

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, C.; Tejada, M.; Gonzalez, J. L.; Benitez, C.

    2009-07-01

    There is currently interest in the use of industrial by-products to reduce the use of synthetic fertilizers. For this reason, in this paper the influence of a phospho-potassic fertilizer solution obtained from a aminoacid production process on wheat crops is studied. The positive influence on leaf potassium contents was most significant when the dosage of phospho-potassic fertilizer solution was applied to bread wheat. (Author)

  17. A hybrid heuristic algorithm for the open-pit-mining operational planning problem.

    OpenAIRE

    Souza, Marcone Jamilson Freitas; Coelho, Igor Machado; Ribas, Sabir; Santos, Haroldo Gambini; Merschmann, Luiz Henrique de Campos

    2010-01-01

    This paper deals with the Open-Pit-Mining Operational Planning problem with dynamic truck allocation. The objective is to optimize mineral extraction in the mines by minimizing the number of mining trucks used to meet production goals and quality requirements. According to the literature, this problem is NPhard, so a heuristic strategy is justified. We present a hybrid algorithm that combines characteristics of two metaheuristics: Greedy Randomized Adaptive Search Procedures and General Varia...

  18. An efficient heuristic for the multi-compartment vehicle routing problem

    OpenAIRE

    Paulo Vitor Silvestrin

    2016-01-01

    We study a variant of the vehicle routing problem that allows vehicles with multiple compartments. The need for multiple compartments frequently arises in practical applications when there are several products of different quality or type, that must be kept or handled separately. The resulting problem is called the multi-compartment vehicle routing problem (MCVRP). We propose a tabu search heuristic and embed it into an iterated local search to solve the MCVRP. In several experiments we analy...

  19. Influent of Carbonization of Sol Solution at the External Gelation Process on the Quality of Uranium Oxide Kernel

    International Nuclear Information System (INIS)

    Damunir; Sukarsono

    2007-01-01

    The influent of carbonization of sol solution at the external gelation process on the quality of uranium oxide kernel was done. Variables observed are the influent of carbon, temperature and time of reduction process of U 3 O 8 kernel resulted from carbonization of sol solution. First of all, uranyl nitrate was reacted with 1 M NH 4 OH solution, producing the colloid of UO 3 . Then by mixing and heating up to the temperature of 60-80 °C, the colloid solution was reacted with PVA, mono sorbitol oleate and paraffin producing of uranium-PVA sol. Then sol solution was carbonized with carbon black of mol ratio of carbon to uranium =2.32-6.62, produce of carbide gel. Gel then washed, dried and calcined at 800 °C for 4 hours to produce of U 3 O 8 kernel containing carbon. Then the kernel was reduced by H 2 gas in the medium of N 2 gas at 500-800 °C, 50 mmHg pressure for 3 hours. The process was repeated at 700 °C, 50 mmHg pressure for 1-4 hours. The characterization of chemical properties of the gel grains and uranium oxide kernel using FTIR covering the analysis of absorption band of infra red spectrum of UO 3 , C-OH, NH 3 , C-C, C-H and OH functional group. The physical properties of uranium oxide covering specific surface area, void volume, mean diameter using surface area meter Nova-1000 and as N 2 gas an absorbent. And O/U ratio of uranium dioxide kernel by gravimetry method. The result of experiment showed that carbonization of sol solution at the external gelation process give influencing the quality of uranium oxide kernel. (author)

  20. Influence of a fertilizer solution on yield and quality of bread wheat in Guadalquivir Valley (Córdoba, Spain)

    Science.gov (United States)

    Concepción Benítez, M.; González, José Luis; Tejada, Manuel

    2014-05-01

    The use of by-products of food industries in agricultural practices has become a routine over the last few decades. The addition of beet vinasse, by-products of the two sep olive mill process and by-products of defatted sunflower flour, etc., to soils is a common agricultural practice, since sensible use has been reported to improve the physical, chemical and biological aspects of the soil and to increase harvest yield, and in many cases harvest quality Previous research carried out by the authors (Ordóñez et al., 2001) examined a process whereby a protein concentrate is obtained from defatted sunflower flour. In this process, floating liquid phosphorus, potassium contents and smaller amounts of humic substances and nitrogen are obtained. The potential application of this solution as a fertiliser has been evaluated on rye grass, confirming that its effects are comparable to those produced by a nutritional solution in terms of phosphorus and potassium foliar levels. The experiment was performed on soil classified as Typic Haploxererts located in the Middle Valley of the river Guadalquivir Cajeme wheat (Triticum aestivum var) variety was used at a dose of 180 kg seeds / ha. For both crop, four fertiliser treatments were applied in triplicate to randomly distributed 7 x 8 m plots. The greatest positive effect of applying the experimental phospho-potassic solution was found for the leaf levels of K, in maturity; this influence was most significant when the highest dosage of said solution. With reference to the levels of N, P and K in wheat grain, the levels of potassium were significantly different for all the fertilising treatments, and the plot fertilised with the highest dosage of the experimental phospho-potassic solution presented the highest values. As for the data obtained for harvest yield and quality, the addition of the experimental solution was observed to have a significantly positive influence (but only in the highest dosages) on the production levels.

  1. Combined Heuristic Attack Strategy on Complex Networks

    Directory of Open Access Journals (Sweden)

    Marek Šimon

    2017-01-01

    Full Text Available Usually, the existence of a complex network is considered an advantage feature and efforts are made to increase its robustness against an attack. However, there exist also harmful and/or malicious networks, from social ones like spreading hoax, corruption, phishing, extremist ideology, and terrorist support up to computer networks spreading computer viruses or DDoS attack software or even biological networks of carriers or transport centers spreading disease among the population. New attack strategy can be therefore used against malicious networks, as well as in a worst-case scenario test for robustness of a useful network. A common measure of robustness of networks is their disintegration level after removal of a fraction of nodes. This robustness can be calculated as a ratio of the number of nodes of the greatest remaining network component against the number of nodes in the original network. Our paper presents a combination of heuristics optimized for an attack on a complex network to achieve its greatest disintegration. Nodes are deleted sequentially based on a heuristic criterion. Efficiency of classical attack approaches is compared to the proposed approach on Barabási-Albert, scale-free with tunable power-law exponent, and Erdős-Rényi models of complex networks and on real-world networks. Our attack strategy results in a faster disintegration, which is counterbalanced by its slightly increased computational demands.

  2. Advances in heuristically based generalized perturbation theory

    International Nuclear Information System (INIS)

    Gandini, A.

    1994-01-01

    A distinctive feature of heuristically based generalized perturbation theory methodology consists in the systematic use of importance conservation concepts. As well known, this use leads to fundamental reciprocity relationship. Instead, the alternative variational and differential one approaches make a consistent use of the properties and adjoint functions. The equivalence between the importance and the adjoint functions have been demonstrated in important cases. There are some instances, however, in which the commonly known operator governing the adjoint function are not adequate. In this paper ways proposed to generalize this rules, as adopted with the heuristic generalized perturbation theory methodology, are illustrated. When applied to the neutron/nuclide field characterizing the core evolution in a power reactor system, in which also an intensive control variable (ρ) is defined, these rules leas to an orthogonality relationship connected to this same control variable. A set of ρ-mode eigenfunctions may be correspondingly defined and an extended concept of reactivity (generalizing that commonly associated with the multiplication factor) proposed as more directly indicative of the controllability of a critical reactor system. (author). 25 refs

  3. A Geographical Heuristic Routing Protocol for VANETs

    Science.gov (United States)

    Urquiza-Aguiar, Luis; Tripp-Barba, Carolina; Aguilar Igartua, Mónica

    2016-01-01

    Vehicular ad hoc networks (VANETs) leverage the communication system of Intelligent Transportation Systems (ITS). Recently, Delay-Tolerant Network (DTN) routing protocols have increased their popularity among the research community for being used in non-safety VANET applications and services like traffic reporting. Vehicular DTN protocols use geographical and local information to make forwarding decisions. However, current proposals only consider the selection of the best candidate based on a local-search. In this paper, we propose a generic Geographical Heuristic Routing (GHR) protocol that can be applied to any DTN geographical routing protocol that makes forwarding decisions hop by hop. GHR includes in its operation adaptations simulated annealing and Tabu-search meta-heuristics, which have largely been used to improve local-search results in discrete optimization. We include a complete performance evaluation of GHR in a multi-hop VANET simulation scenario for a reporting service. Our study analyzes all of the meaningful configurations of GHR and offers a statistical analysis of our findings by means of MANOVA tests. Our results indicate that the use of a Tabu list contributes to improving the packet delivery ratio by around 5% to 10%. Moreover, if Tabu is used, then the simulated annealing routing strategy gets a better performance than the selection of the best node used with carry and forwarding (default operation). PMID:27669254

  4. Slime moulds use heuristics based on within-patch experience to decide when to leave.

    Science.gov (United States)

    Latty, Tanya; Beekman, Madeleine

    2015-04-15

    Animals foraging in patchy, non-renewing or slowly renewing environments must make decisions about how long to remain within a patch. Organisms can use heuristics ('rules of thumb') based on available information to decide when to leave the patch. Here, we investigated proximate patch-departure heuristics in two species of giant, brainless amoeba: the slime moulds Didymium bahiense and Physarum polycephalum. We explicitly tested the importance of information obtained through experience by eliminating chemosensory cues of patch quality. In P. polycephalum, patch departure was influenced by the consumption of high, and to a much lesser extent low, quality food items such that engulfing a food item increased patch-residency time. Physarum polycephalum also tended to forage for longer in darkened, 'safe' patches. In D. bahiense, engulfment of any food item increased patch residency irrespective of that food item's quality. Exposure to light had no effect on the patch-residency time of D. bahiense. Given that these organisms lack a brain, our results illustrate how the use of simple heuristics can give the impression that individuals make sophisticated foraging decisions. © 2015. Published by The Company of Biologists Ltd.

  5. Proposing buffer zones and simple technical solutions for safeguarding river water quality and public health

    Science.gov (United States)

    Podimata, M. V.; Bekri, E. S.; Yannopoulos, P. C.

    2012-04-01

    Alfeios River Basin (ARB) constitutes one of the major hydrologic basins (≈3650km2) of Peloponnisos peninsula in Southern Greece. It is drained by Alfeios River and its tributaries, such as Lousios, Ladhon, Erymanthos, Kladheos, Selinous etc. The present manuscript takes a closer look at the importance of tributary basins and focuses on Erymanthos sub-basin that covers about 360 km2. Erymanthos River springs from Erymanthos Mountain that reaches altitudes of 2200 m and discharges 10 m3/sec, approximately, during the winter period, presenting a sound decrease from half to about an order of magnitude during summertime. Two factors stand out as reasons to select Erymanthos sub-basin as a case study. First, the sub-basin presents a significant variety of ecosystems and comprises a very important river system, since Erymanthos Tributary satisfies, among other uses, drinking water supply for a great majority of citizens in the region. Second, authors' experience of the study area in Research Program Pythagoras II, funded by the European Social Fund (ESF) and the Operational Program for Educational and Vocational Training II (EPEAEK II) of Greece, offers a basis for better understanding of the real problems in the area. Erymanthos watershed, in fact, faces a lot of pressures, in several levels, provoked by human activities and Erymanthos Tributary is vulnerable to pollution. Recognizing the importance of clean water for healthy people, a developing economy, and a sustainable environment, the challenge of the present paper is elaborating human-induced pressures in the study area, analyzing their effects, estimating pollution factors and proposing integrated solutions/tools and a number of methodologies/initiatives used to overcome the problem of contaminating water supply in a catchment that lacks of wastewater treatment and disposal systems. The preservation of a good ecological status in Erymanthos River is not only a necessity for achieving the goals of EU Water

  6. Challenge in manufacturing electrolyte solutions for lithium and lithium ion batteries quality control and minimizing contamination level

    Science.gov (United States)

    Heider, U.; Oesten, R.; Jungnitz, M.

    The quality of electrolytes for lithium batteries are a major topic in science and battery industries. The solvents and lithium salts should be of highest purity. Therefore, during preparation and handling of electrolyte solutions, the contamination level has to be minimized and the quality during packaging, storage and transportation has to be guaranteed. Especially, protic impurities are found to be very critical for LiPF 6-based electrolytes. The influence of water is reported to be tremendous. But also other protic impurities like alcohols are considered to play an important role in the electrolyte quality. The reaction of the protic impurities with LiPF 6 leads to the formation of HF which further reacts with cathode active materials (e.g., spinel) and the passivating films of the cathode and anode. For a better understanding of the protic impurities and their role in the electrolyte quality a systematic investigation of different impurities was carried out. Electrolytes were doped with different protic compounds. Then the electrolyte was analyzed for protic impurities and HF in dependence of time. First results showing the relation between protic impurities and HF are presented and discussed. In addition, different packaging materials for the electrolyte solutions were investigated. Storage tests were carried out at different temperatures and in different atmospheres. Results on contamination levels, influence of packaging, high temperature storage and handling are addressed.

  7. Hybrid Experiential-Heuristic Cognitive Radio Engine Architecture and Implementation

    Directory of Open Access Journals (Sweden)

    Ashwin Amanna

    2012-01-01

    Full Text Available The concept of cognitive radio (CR focuses on devices that can sense their environment, adapt configuration parameters, and learn from past behaviors. Architectures tend towards simplified decision-making algorithms inspired by human cognition. Initial works defined cognitive engines (CEs founded on heuristics, such as genetic algorithms (GAs, and case-based reasoning (CBR experiential learning algorithms. This hybrid architecture enables both long-term learning, faster decisions based on past experience, and capability to still adapt to new environments. This paper details an autonomous implementation of a hybrid CBR-GA CE architecture on a universal serial radio peripheral (USRP software-defined radio focused on link adaptation. Details include overall process flow, case base structure/retrieval method, estimation approach within the GA, and hardware-software lessons learned. Unique solutions to realizing the concept include mechanisms for combining vector distance and past fitness into an aggregate quantification of similarity. Over-the-air performance under several interference conditions is measured using signal-to-noise ratio, packet error rate, spectral efficiency, and throughput as observable metrics. Results indicate that the CE is successfully able to autonomously change transmit power, modulation/coding, and packet size to maintain the link while a non-cognitive approach loses connectivity. Solutions to existing shortcomings are proposed for improving case-base searching and performance estimation methods.

  8. Runway Operations Planning: A Two-Stage Heuristic Algorithm

    Science.gov (United States)

    Anagnostakis, Ioannis; Clarke, John-Paul

    2003-01-01

    The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, can also be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. This paper introduces a two stage heuristic algorithm for solving the Runway Operations Planning (ROP) problem. In the first stage, sequences of departure class slots and runway crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program with a Branch & Bound algorithm implementation. Preliminary results from this implementation of the two-stage algorithm on real-world traffic data are presented.

  9. Cost optimization model and its heuristic genetic algorithms

    International Nuclear Information System (INIS)

    Liu Wei; Wang Yongqing; Guo Jilin

    1999-01-01

    Interest and escalation are large quantity in proportion to the cost of nuclear power plant construction. In order to optimize the cost, the mathematics model of cost optimization for nuclear power plant construction was proposed, which takes the maximum net present value as the optimization goal. The model is based on the activity networks of the project and is an NP problem. A heuristic genetic algorithms (HGAs) for the model was introduced. In the algorithms, a solution is represented with a string of numbers each of which denotes the priority of each activity for assigned resources. The HGAs with this encoding method can overcome the difficulty which is harder to get feasible solutions when using the traditional GAs to solve the model. The critical path of the activity networks is figured out with the concept of predecessor matrix. An example was computed with the HGAP programmed in C language. The results indicate that the model is suitable for the objectiveness, the algorithms is effective to solve the model

  10. Probabilistic dual heuristic programming-based adaptive critic

    Science.gov (United States)

    Herzallah, Randa

    2010-02-01

    Adaptive critic (AC) methods have common roots as generalisations of dynamic programming for neural reinforcement learning approaches. Since they approximate the dynamic programming solutions, they are potentially suitable for learning in noisy, non-linear and non-stationary environments. In this study, a novel probabilistic dual heuristic programming (DHP)-based AC controller is proposed. Distinct to current approaches, the proposed probabilistic (DHP) AC method takes uncertainties of forward model and inverse controller into consideration. Therefore, it is suitable for deterministic and stochastic control problems characterised by functional uncertainty. Theoretical development of the proposed method is validated by analytically evaluating the correct value of the cost function which satisfies the Bellman equation in a linear quadratic control problem. The target value of the probabilistic critic network is then calculated and shown to be equal to the analytically derived correct value. Full derivation of the Riccati solution for this non-standard stochastic linear quadratic control problem is also provided. Moreover, the performance of the proposed probabilistic controller is demonstrated on linear and non-linear control examples.

  11. Application of a heuristic search method for generation of fuel reload configurations

    International Nuclear Information System (INIS)

    Galperin, A.; Nissan, E.

    1988-01-01

    A computerized heuristic search method for the generation and optimization of fuel reload configurations is proposed and investigated. The heuristic knowledge is expressed modularly in the form of ''IF-THEN'' production rules. The method was implemented in a program coded in the Franz LISP programming language and executed under the UNIX operating system. A test problem was formulated, based on a typical light water reactor reload problem with a few simplifications assumed, in order to allow formulation of the reload strategy into a relatively small number of rules. A computer run of the problem was performed with a VAX-780 machine. A set of 312 solutions was generated in -- 20 min of execution time. Testing of a few arbitrarily chosen configurations demonstrated reasonably good performance for the computer-generated solutions. A computerized generator of reload configurations may be used for the fast generation or modification of reload patterns and as a tool for the formulation, tuning, and testing of the heuristic knowledge rules used by an ''expert'' fuel manager

  12. Heuristic model of education and a prototype of a system for remote siren activation in emergency

    Directory of Open Access Journals (Sweden)

    Paun Josif Bereš

    2013-02-01

    Full Text Available A heuristic models of methodical innovation with special emphasis on training of team members to work in emergency situations, where each team member must be aware of the importance of their work, must know and apply a methodology for finding the best solutions and feel satisfaction with the results as an individual and as a part of that team, are proposed in this paper. Heuristic approach to the problems of teaching in emergency situations should allow team members to come up with the creative process of acquiring knowledge, to learn to think and develop skills for education. It is, therefore, such an approach that is not based on passive observation of phenomena and impersonation performed by a teacher, but establishes an active relationship to phenomena of thought and introduces the team members in their own research of the heuristic concept problems with the range of solutions - in this case, " Digital Communications - a program of operational functions of mobile phones ", the function of emergency situations, the example of a prototype system for automatic activation of the alert - sirens.

  13. Augmented neural networks and problem structure-based heuristics for the bin-packing problem

    Science.gov (United States)

    Kasap, Nihat; Agarwal, Anurag

    2012-08-01

    In this article, we report on a research project where we applied augmented-neural-networks (AugNNs) approach for solving the classical bin-packing problem (BPP). AugNN is a metaheuristic that combines a priority rule heuristic with the iterative search approach of neural networks to generate good solutions fast. This is the first time this approach has been applied to the BPP. We also propose a decomposition approach for solving harder BPP, in which subproblems are solved using a combination of AugNN approach and heuristics that exploit the problem structure. We discuss the characteristics of problems on which such problem structure-based heuristics could be applied. We empirically show the effectiveness of the AugNN and the decomposition approach on many benchmark problems in the literature. For the 1210 benchmark problems tested, 917 problems were solved to optimality and the average gap between the obtained solution and the upper bound for all the problems was reduced to under 0.66% and computation time averaged below 33 s per problem. We also discuss the computational complexity of our approach.

  14. A HYBRID HEURISTIC ALGORITHM FOR SOLVING THE RESOURCE CONSTRAINED PROJECT SCHEDULING PROBLEM (RCPSP

    Directory of Open Access Journals (Sweden)

    Juan Carlos Rivera

    Full Text Available The Resource Constrained Project Scheduling Problem (RCPSP is a problem of great interest for the scientific community because it belongs to the class of NP-Hard problems and no methods are known that can solve it accurately in polynomial processing times. For this reason heuristic methods are used to solve it in an efficient way though there is no guarantee that an optimal solution can be obtained. This research presents a hybrid heuristic search algorithm to solve the RCPSP efficiently, combining elements of the heuristic Greedy Randomized Adaptive Search Procedure (GRASP, Scatter Search and Justification. The efficiency obtained is measured taking into account the presence of the new elements added to the GRASP algorithm taken as base: Justification and Scatter Search. The algorithms are evaluated using three data bases of instances of the problem: 480 instances of 30 activities, 480 of 60, and 600 of 120 activities respectively, taken from the library PSPLIB available online. The solutions obtained by the developed algorithm for the instances of 30, 60 and 120 are compared with results obtained by other researchers at international level, where a prominent place is obtained, according to Chen (2011.

  15. Plasma Modification of Poly Lactic Acid Solutions to Generate High Quality Electrospun PLA Nanofibers.

    Science.gov (United States)

    Rezaei, Fatemeh; Nikiforov, Anton; Morent, Rino; De Geyter, Nathalie

    2018-02-02

    Physical properties of pre-electrospinning polymer solutions play a key role in electrospinning as they strongly determine the morphology of the obtained electrospun nanofibers. In this work, an atmospheric-pressure argon plasma directly submerged in the liquid-phase was used to modify the physical properties of poly lactic acid (PLA) spinning solutions in an effort to improve their electrospinnability. The electrical characteristics of the plasma were investigated by two methods; V-I waveforms and Q-V Lissajous plots while the optical emission characteristics of the plasma were also determined using optical emission spectroscopy (OES). To perform a complete physical characterization of the plasma-modified polymer solutions, measurements of viscosity, surface tension, and electrical conductivity were performed for various PLA concentrations, plasma exposure times, gas flow rates, and applied voltages. Moreover, a fast intensified charge-couple device (ICCD) camera was used to image the bubble dynamics during the plasma treatments. In addition, morphological changes of PLA nanofibers generated from plasma-treated PLA solutions were observed by scanning electron microscopy (SEM). The performed plasma treatments were found to induce significant changes to the main physical properties of the PLA solutions, leading to an enhancement of electrospinnability and an improvement of PLA nanofiber formation.

  16. Effect of uranyl nitrate and free acid concentration in feed solution of gelation on UO2 kernel quality

    International Nuclear Information System (INIS)

    Masduki, B.; Wardaya; Widarmoko, A.

    1996-01-01

    An investigation on the effect of uranium and free nitric acid concentration of uranyl nitrate as feed of gelation process on quality of UO 2 kernel was done.The investigation is to look for some concentration of uranyl nitrate solutions those are optimum as feed for preparation of gelled UO 3 . Uranyl nitrate solution of various concentration of uranium (450; 500; 550; 600; 650; 700 g/l) and free nitric acid of (0.9; 1.0; 1.1 N) was made into feed solutions by adding urea and HMTA with mole ratio of urea/uranium and HMTA/uranium 2.1 and 2.0. The feed solutions were changed into spherical gelled UO 3 by dropping was done to get the optimum concentrations of uranyl nitrate solutions. The gelled UO 3 was soaked and washed with 2.5% ammonia solution for 17 hours, dried at 70 o C, calcined at 350 o C for 3 hours then reduced at 850 o C for 3 hours. At every step of the steps process the colour and percentage of well product of gelled UO 3 were noticed. The density and O/U ratio of end product (UO 2 kernel) was determined, the percentage of well product of all steps process was also determined. The three factor were used to chose the optimum concentration of uranyl nitrate solution. From this investigation it was concluded that the optimum concentration of uranyl nitrate was 600 g/l uranium with free nitric acid 0,9 - 1,0 N, the percentage of well product was 97% density of 6.12 - 4.8 g/cc and O/U ratio of 2.15 - 2.06. (author)

  17. Use of Statistical Heuristics in Everyday Inductive Reasoning.

    Science.gov (United States)

    Nisbett, Richard E.; And Others

    1983-01-01

    In everyday reasoning, people use statistical heuristics (judgmental tools that are rough intuitive equivalents of statistical principles). Use of statistical heuristics is more likely when (1) sampling is clear, (2) the role of chance is clear, (3) statistical reasoning is normative for the event, or (4) the subject has had training in…

  18. A Priori Knowledge and Heuristic Reasoning in Architectural Design.

    Science.gov (United States)

    Rowe, Peter G.

    1982-01-01

    It is proposed that the various classes of a priori knowledge incorporated in heuristic reasoning processes exert a strong influence over architectural design activity. Some design problems require exercise of some provisional set of rules, inference, or plausible strategy which requires heuristic reasoning. A case study illustrates this concept.…

  19. Refining a Heuristic for Constructing Bayesian Networks from Structured Arguments

    NARCIS (Netherlands)

    Wieten, G.M.; Bex, F.J.; van der Gaag, L.C.; Prakken, H.; Renooij, S.

    2018-01-01

    Recently, a heuristic was proposed for constructing Bayesian networks (BNs) from structured arguments. This heuristic helps domain experts who are accustomed to argumentation to transform their reasoning into a BN and subsequently weigh their case evidence in a probabilistic manner. While the

  20. Heuristic Inquiry: A Personal Journey of Acculturation and Identity Reconstruction

    Science.gov (United States)

    Djuraskovic, Ivana; Arthur, Nancy

    2010-01-01

    Heuristic methodology attempts to discover the nature and meaning of phenomenon through internal self-search, exploration, and discovery. Heuristic methodology encourages the researcher to explore and pursue the creative journey that begins inside one's being and ultimately uncovers its direction and meaning through internal discovery (Douglass &…

  1. Hyper-heuristics with low level parameter adaptation.

    Science.gov (United States)

    Ren, Zhilei; Jiang, He; Xuan, Jifeng; Luo, Zhongxuan

    2012-01-01

    Recent years have witnessed the great success of hyper-heuristics applying to numerous real-world applications. Hyper-heuristics raise the generality of search methodologies by manipulating a set of low level heuristics (LLHs) to solve problems, and aim to automate the algorithm design process. However, those LLHs are usually parameterized, which may contradict the domain independent motivation of hyper-heuristics. In this paper, we show how to automatically maintain low level parameters (LLPs) using a hyper-heuristic with LLP adaptation (AD-HH), and exemplify the feasibility of AD-HH by adaptively maintaining the LLPs for two hyper-heuristic models. Furthermore, aiming at tackling the search space expansion due to the LLP adaptation, we apply a heuristic space reduction (SAR) mechanism to improve the AD-HH framework. The integration of the LLP adaptation and the SAR mechanism is able to explore the heuristic space more effectively and efficiently. To evaluate the performance of the proposed algorithms, we choose the p-median problem as a case study. The empirical results show that with the adaptation of the LLPs and the SAR mechanism, the proposed algorithms are able to achieve competitive results over the three heterogeneous classes of benchmark instances.

  2. Experimental Matching of Instances to Heuristics for Constraint Satisfaction Problems.

    Science.gov (United States)

    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.

  3. Fairness and other leadership heuristics: A four-nation study

    NARCIS (Netherlands)

    Janson, A.; Levy, L.; Sitkin, S.B.; Lind, E.A.

    2008-01-01

    Leaders' fairness may be just one of several heuristics - cognitive shortcuts - that followers use to decide quickly whether they can rely on a given leader to lead them to ends that are good for the collective, rather than just good for the leader. Other leadership heuristics might include leader

  4. HEURISTIC OPTIMIZATION AND ALGORITHM TUNING APPLIED TO SORPTIVE BARRIER DESIGN

    Science.gov (United States)

    While heuristic optimization is applied in environmental applications, ad-hoc algorithm configuration is typical. We use a multi-layer sorptive barrier design problem as a benchmark for an algorithm-tuning procedure, as applied to three heuristics (genetic algorithms, simulated ...

  5. On Dual Processing and Heuristic Approaches to Moral Cognition

    Science.gov (United States)

    Lapsley, Daniel K.; Hill, Patrick L.

    2008-01-01

    We examine the implications of dual-processing theories of cognition for the moral domain, with particular emphasis upon "System 1" theories: the Social Intuitionist Model (Haidt), moral heuristics (Sunstein), fast-and-frugal moral heuristics (Gigerenzer), schema accessibility (Lapsley & Narvaez) and moral expertise (Narvaez). We argue that these…

  6. Efficient Heuristics for Simulating Population Overflow in Parallel Networks

    NARCIS (Netherlands)

    Zaburnenko, T.S.; Nicola, V.F.

    2006-01-01

    In this paper we propose a state-dependent importance sampling heuristic to estimate the probability of population overflow in networks of parallel queues. This heuristic approximates the “optimal��? state-dependent change of measure without the need for costly optimization involved in other

  7. Swift and Smart Decision Making: Heuristics that Work

    Science.gov (United States)

    Hoy, Wayne K.; Tarter, C. J.

    2010-01-01

    Purpose: The aim of this paper is to examine the research literature on decision making and identify and develop a set of heuristics that work for school decision makers. Design/methodology/approach: This analysis is a synthesis of the research on decision-making heuristics that work. Findings: A set of nine rules for swift and smart decision…

  8. Does the inherence heuristic take us to psychological essentialism?

    Science.gov (United States)

    Marmodoro, Anna; Murphy, Robin A; Baker, A G

    2014-10-01

    We argue that the claim that essence-based causal explanations emerge, hydra-like, from an inherence heuristic is incomplete. No plausible mechanism for the transition from concrete properties, or cues, to essences is provided. Moreover, the fundamental shotgun and storytelling mechanisms of the inherence heuristic are not clearly enough specified to distinguish them, developmentally, from associative or causal networks.

  9. Ship Routing with Pickup and Delivery for a Maritime Oil Transportation System: MIP Modeland Heuristics

    DEFF Research Database (Denmark)

    Rodrigues, Vinicius Picanco; Morabito, Reinaldo; Yamashita, Denise

    2016-01-01

    This paper examines a ship routing problem with pickup and delivery and time windowsfor maritime oil transportation, motivated by the production and logistics activities of an oil companyoperating in the Brazilian coast. The transportation costs from offshore platforms to coastal terminalsare...... application of two tailor-made MIP heuristics, based on relax-and-fix and timedecomposition procedures. The model minimizes fuel costs of a heterogeneous fleet of oil tankersand costs related to freighting contracts. The model also considers company-specific constraints foroffshore oil transportation....... Computational experiments based on the mathematical models and therelated MIP heuristics are presented for a set of real data provided by the company, which confirmthe potential of optimization-based methods to find good solutions for problems of moderate sizes....

  10. Steiner tree heuristic in the Euclidean d-space using bottleneck distances

    DEFF Research Database (Denmark)

    Lorenzen, Stephan Sloth; Winter, Pawel

    2016-01-01

    Some of the most efficient heuristics for the Euclidean Steiner minimal tree problem in the d-dimensional space, d ≥2, use Delaunay tessellations and minimum spanning trees to determine small subsets of geometrically close terminals. Their low-cost Steiner trees are determined and concatenated...... in a greedy fashion to obtain a low cost tree spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To avoid this and to obtain even better solutions, bottleneck distances are utilized to determine good subsets of terminals...

  11. Mining the multigroup-discrete ordinates algorithm for high quality solutions

    International Nuclear Information System (INIS)

    Ganapol, B.D.; Kornreich, D.E.

    2005-01-01

    A novel approach to the numerical solution of the neutron transport equation via the discrete ordinates (SN) method is presented. The new technique is referred to as 'mining' low order (SN) numerical solutions to obtain high order accuracy. The new numerical method, called the Multigroup Converged SN (MGCSN) algorithm, is a combination of several sequence accelerators: Romberg and Wynn-epsilon. The extreme accuracy obtained by the method is demonstrated through self consistency and comparison to the independent semi-analytical benchmark BLUE. (authors)

  12. Knowledge discovery in hyper-heuristic using case-based reasoning on course timetabling

    OpenAIRE

    Burke, Edmund; MacCarthy, Bart L.; Petrovic, Sanja; Qu, Rong

    2002-01-01

    This paper presents a new hyper-heuristic method using Case-Based Reasoning (CBR) for solving course timetabling problems. The term Hyper-heuristics has recently been employed to refer to 'heuristics that choose heuristics' rather than heuristics that operate directly on given problems. One of the overriding motivations of hyper-heuristic methods is the attempt to develop techniques that can operate with greater generality than is currently possible. The basic idea behind this is that we main...

  13. Quality control test solutions for diagnostic radiology, nuclear medicine and health physics with PTW equipment

    International Nuclear Information System (INIS)

    Froescher, Olga

    2007-01-01

    Complete test of publication follows. In 1922 PTW-Freiburg was founded to produce and market a revolutionary new electromechanical component for measuring very small electrical charges. Today PTW is the specialist and one of the global market leaders for manufacturing and supplying high-quality products in diagnostic radiology, nuclear medicine, radiation therapy and health physics. The quality control of X-ray images is influenced by a number of parameters. To maintain a consistent performance of X-ray installations, quality checks have to be conducted regularly. PTW offers a variety of diagnostic test tools for different X-ray devices, and therefore to reduce patient exposure and costs for X-ray departments. PTW's 'Code of Practice' defines in an easy and compact way how to perform quality control measurements on different diagnostic X-ray installations. The necessary equipment for measuring main parameters as well as acceptable limits are mentioned accordingly. The 'Code of Practice' bases on actual standards.

  14. Heuristic Diagrams as a Tool to Teach History of Science

    Science.gov (United States)

    Chamizo, José A.

    2012-05-01

    The graphic organizer called here heuristic diagram as an improvement of Gowin's Vee heuristic is proposed as a tool to teach history of science. Heuristic diagrams have the purpose of helping students (or teachers, or researchers) to understand their own research considering that asks and problem-solving are central to scientific activity. The left side originally related in Gowin's Vee with philosophies, theories, models, laws or regularities now agrees with Toulmin's concepts (language, models as representation techniques and application procedures). Mexican science teachers without experience in science education research used the heuristic diagram to learn about the history of chemistry considering also in the left side two different historical times: past and present. Through a semantic differential scale teachers' attitude to the heuristic diagram was evaluated and its usefulness was demonstrated.

  15. An electrorheological investigation of PVB solutions in connection with their electrospinning qualities

    Czech Academy of Sciences Publication Activity Database

    Peer, Petra; Stěnička, M.; Pavlínek, V.; Filip, Petr; Kuřitka, I.; Brus, Jiří

    2014-01-01

    Roč. 39, October (2014), s. 115-121 ISSN 0142-9418 R&D Projects: GA ČR(CZ) GAP105/11/2342 Institutional support: RVO:67985874 ; RVO:61389013 Keywords : electrospinning * nanofibres * polyvinylbutyral * electrorheology * polymer solution Subject RIV: BK - Fluid Dynamics; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 2.240, year: 2014

  16. Quality assessment in in vivo NMR spectroscopy: III. Clinical test objects: design, construction, and solutions

    DEFF Research Database (Denmark)

    Leach, M.O.; Collins, D.J.; Keevil, S

    1995-01-01

    /Perspex interface produced minimum susceptibility effects. The design of the objects has been evaluated in trials on different magnetic resonance instruments, with size and loading being adjusted to allow use on currently available equipment. Appropriate test solutions for 31P and 1H measurements have been...

  17. Nanofibrous web quality in dependence on the preparation of poly(ethylene oxide) aqueous solutions

    Czech Academy of Sciences Publication Activity Database

    Peer, Petra; Filip, Petr

    2017-01-01

    Roč. 108, č. 12 (2017), s. 2021-2026 ISSN 0040-5000 R&D Projects: GA ČR GA17-26808S Institutional support: RVO:67985874 Keywords : nanofibrous web * poly(ethylene oxide) solution * magnetic stirring * vibrational shaking Subject RIV: BK - Fluid Dynamics OBOR OECD: Polymer science Impact factor: 1.007, year: 2016

  18. Use of commercial sodium hypochlorite solutions in respect to the quality of the products

    OpenAIRE

    Gjorgjeska, Biljana; Kovacevska, Ivona; Dimova, Cena

    2012-01-01

    Sodium hypochlorite is the most popular solution for root canal irrigation in stomatology practice. NaOCl ionizes in water into hypochlorite ion OCl-, establishing an equilibrium with hypochlorous acid (HOCl). At acidic and neutral pH, chlorine exists predominantly as HOCl, whereas at high pH of 9 and above, OCl- predominates.

  19. Meta-heuristic algorithms for parallel identical machines scheduling problem with weighted late work criterion and common due date.

    Science.gov (United States)

    Xu, Zhenzhen; Zou, Yongxing; Kong, Xiangjie

    2015-01-01

    To our knowledge, this paper investigates the first application of meta-heuristic algorithms to tackle the parallel machines scheduling problem with weighted late work criterion and common due date ([Formula: see text]). Late work criterion is one of the performance measures of scheduling problems which considers the length of late parts of particular jobs when evaluating the quality of scheduling. Since this problem is known to be NP-hard, three meta-heuristic algorithms, namely ant colony system, genetic algorithm, and simulated annealing are designed and implemented, respectively. We also propose a novel algorithm named LDF (largest density first) which is improved from LPT (longest processing time first). The computational experiments compared these meta-heuristic algorithms with LDF, LPT and LS (list scheduling), and the experimental results show that SA performs the best in most cases. However, LDF is better than SA in some conditions, moreover, the running time of LDF is much shorter than SA.

  20. Relationships between undergraduates' argumentation skills, conceptual quality of problem solutions, and problem solving strategies in introductory physics

    Science.gov (United States)

    Rebello, Carina M.

    This study explored the effects of alternative forms of argumentation on undergraduates' physics solutions in introductory calculus-based physics. A two-phase concurrent mixed methods design was employed to investigate relationships between undergraduates' written argumentation abilities, conceptual quality of problem solutions, as well as approaches and strategies for solving argumentative physics problems across multiple physics topics. Participants were assigned via stratified sampling to one of three conditions (control, guided construct, or guided evaluate) based on gender and pre-test scores on a conceptual instrument. The guided construct and guided evaluate groups received tasks and prompts drawn from literature to facilitate argument construction or evaluation. Using a multiple case study design, with each condition serving as a case, interviews were conducted consisting of a think-aloud problem solving session paired with a semi-structured interview. The analysis of problem solving strategies was guided by the theoretical framework on epistemic games adapted by Tuminaro and Redish (2007). This study provides empirical evidence that integration of written argumentation into physics problems can potentially improve the conceptual quality of solutions, expand their repertoire of problem solving strategies and show promise for addressing the gender gap in physics. The study suggests further avenues for research in this area and implications for designing and implementing argumentation tasks in introductory college physics.

  1. Evaluation of adjustment functions in a heuristic algorithm; Evaluacion de funciones de ajuste en un algoritmo heuristico

    Energy Technology Data Exchange (ETDEWEB)

    Perusquia del Cueto, R.; Montes T, J. L.; Ortiz S, J. J.; Castillo M, A., E-mail: raul.perusquia@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    At present the techniques of evolution al computation receive an increasing attention in the scientific and technological areas. This situation is due to its enormous potential in the optimization applied to problems of discussed computational complexity. In the nuclear area these techniques are used in diverse problems of combinatory optimization related with designing cores of power reactors. A distinctive characteristic of the evolution al and/or meta-heuristic algorithms is that appeal in each one from their applications to an adjustment function, fitness or of quality. This function allows to discriminate or to evaluate potentials solutions of the problem to solve. The definition of this situation is very important since it allows following the search of the algorithm toward different regions of the search space. In this work the impact that has the election of this function in the quality of the found solution is shown. The optimization technique by ant colonies or Acs (ant colony system) was used applied to the radial design of fuel cells for a boiling water power reactor. The notable results of the Acs allowed to propose the adjustment method of the importance and with this to obtain adjustment functions that guide the search of solutions of collective algorithms efficiently, basic capacity to develop the proposal of emulation of the natural selection and to investigate the possibility that on order of specify goals, to obtain the corresponding decision variables. A variety of re tro-exit (re tro-out) complementary process of feedback (re tro-in) that opens extended application perspectives of be feasible. (Author)

  2. XERG-mammography system: a solution to the dose-quality problem

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, M

    1981-05-01

    The XERG (Xonics-Electron-Radio-Graphy) system is the first ionographic system (High-Pressure-Gas-Iono-graphy) suitable for clinical application which became available for testing. The basic principle, the function and imaging qualities of the XERG system are described and first clinical experiences reported. The XERG mammogram is a transparent X-ray negative image, the image quality of which is characterized by good general image contrast, a moderate edge-effect and a high quantum-noise level but giving an extremely low dose rate (4.5% compared to screenless mammography film). Although the XERG quality is not satisfactory in contact technique, it yields results which are equal in quality, when using a 1.5-fold magnification technique, to the results obtained with screenless film mammography at one-tenth of the dose, and is superior to any commercially available film-screen system. Hence, in our opinion, the XERG mammography system is a step forward towards high-quality low-dose mammography.

  3. A decomposition heuristics based on multi-bottleneck machines for large-scale job shop scheduling problems

    Directory of Open Access Journals (Sweden)

    Yingni Zhai

    2014-10-01

    Full Text Available Purpose: A decomposition heuristics based on multi-bottleneck machines for large-scale job shop scheduling problems (JSP is proposed.Design/methodology/approach: In the algorithm, a number of sub-problems are constructed by iteratively decomposing the large-scale JSP according to the process route of each job. And then the solution of the large-scale JSP can be obtained by iteratively solving the sub-problems. In order to improve the sub-problems' solving efficiency and the solution quality, a detection method for multi-bottleneck machines based on critical path is proposed. Therewith the unscheduled operations can be decomposed into bottleneck operations and non-bottleneck operations. According to the principle of “Bottleneck leads the performance of the whole manufacturing system” in TOC (Theory Of Constraints, the bottleneck operations are scheduled by genetic algorithm for high solution quality, and the non-bottleneck operations are scheduled by dispatching rules for the improvement of the solving efficiency.Findings: In the process of the sub-problems' construction, partial operations in the previous scheduled sub-problem are divided into the successive sub-problem for re-optimization. This strategy can improve the solution quality of the algorithm. In the process of solving the sub-problems, the strategy that evaluating the chromosome's fitness by predicting the global scheduling objective value can improve the solution quality.Research limitations/implications: In this research, there are some assumptions which reduce the complexity of the large-scale scheduling problem. They are as follows: The processing route of each job is predetermined, and the processing time of each operation is fixed. There is no machine breakdown, and no preemption of the operations is allowed. The assumptions should be considered if the algorithm is used in the actual job shop.Originality/value: The research provides an efficient scheduling method for the

  4. [The heuristics of reaching a diagnosis].

    Science.gov (United States)

    Wainstein, Eduardo

    2009-12-01

    Making a diagnosis in medicine is a complex process in which many cognitive and psychological issues are involved. After the first encounter with the patient, an unconscious process ensues to suspect the presence of a particular disease. Usually, complementary tests are requested to confirm the clinical suspicion. The interpretation of requested tests can be biased by the clinical diagnosis that was considered in the first encounter with the patient. The awareness of these sources of error is essential in the interpretation of the findings that will eventually lead to a final diagnosis. This article discusses some aspects of the heuristics involved in the adjudication of priory probabilities and provides a brief review of current concepts of the reasoning process.

  5. Primary calibrations of radionuclide solutions and sources for the EML quality assessment program

    Energy Technology Data Exchange (ETDEWEB)

    Fisenne, I.M. [Dept. of Energy, New York, NY (United States)

    1993-12-31

    The quality assurance procedures established for the operation of the U.S. Department of Energy`s Environmental Measurements Laboratory (DOE-EML`s) Quality Assessment Program (QAP) are essentially the same as those that are in effect for any EML program involving radiometric measurements. All these programs have at their core the use of radionuclide standards for their instrument calibration. This paper focuses on EML`s approach to the acquisition, calibration and application of a wide range of radionuclide sources that are required to meet its programmatic needs.

  6. Detection and Solution of Indoor Air Quality Problems in a Danish Town Hall

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik; Brohus, Henrik

    In connection with the research programme "Healthy Buildings", a building with indoor air quality problems was selected for further investigations. A Danish town hall was chosen because of many complaints over several years. A full-scale mock-up of a typical town hall office was built...... in the climate laboratory. A new heating and ventilating system and a new control strategy were chosen and implemented into the town hall. It was found that air supply upwards along a window may make it nearly impossible to achieve comfort and a good air quality the year round without full-scale measurements....

  7. High-quality fiber fabrication in buffered hydrofluoric acid solution with ultrasonic agitation.

    Science.gov (United States)

    Zhong, Nianbing; Liao, Qiang; Zhu, Xun; Wang, Yongzhong; Chen, Rong

    2013-03-01

    An etching method for preparing high-quality fiber-optic sensors using a buffered etchant with ultrasonic agitation is proposed. The effects of etching conditions on the etch rate and surface morphology of the etched fibers are investigated. The effect of surface roughness is discussed on the fibers' optical properties. Linear etching behavior and a smooth fiber surface can be repeatedly obtained by adjusting the ultrasonic power and etchant pH. The fibers' spectral quality is improved as the ratio of the pit depth to size decreases, and the fibers with smooth surfaces are more sensitive to a bacterial suspension than those with rough surfaces.

  8. Heuristics and bias in rectal surgery.

    Science.gov (United States)

    MacDermid, Ewan; Young, Christopher J; Moug, Susan J; Anderson, Robert G; Shepherd, Heather L

    2017-08-01

    Deciding to defunction after anterior resection can be difficult, requiring cognitive tools or heuristics. From our previous work, increasing age and risk-taking propensity were identified as heuristic biases for surgeons in Australia and New Zealand (CSSANZ), and inversely proportional to the likelihood of creating defunctioning stomas. We aimed to assess these factors for colorectal surgeons in the British Isles, and identify other potential biases. The Association of Coloproctology of Great Britain and Ireland (ACPGBI) was invited to complete an online survey. Questions included demographics, risk-taking propensity, sensitivity to professional criticism, self-perception of anastomotic leak rate and propensity for creating defunctioning stomas. Chi-squared testing was used to assess differences between ACPGBI and CSSANZ respondents. Multiple regression analysis identified independent surgeon predictors of stoma formation. One hundred fifty (19.2%) eligible members of the ACPGBI replied. Demographics between ACPGBI and CSSANZ groups were well-matched. Significantly more ACPGBI surgeons admitted to anastomotic leak in the last year (p < 0.001). ACPGBI surgeon age over 50 (p = 0.02), higher risk-taking propensity across several domains (p = 0.044), self-belief in a lower-than-average anastomotic leak rate (p = 0.02) and belief that the average risk of leak after anterior resection is 8% or lower (p = 0.007) were all independent predictors of less frequent stoma formation. Sensitivity to criticism from colleagues was not a predictor of stoma formation. Unrecognised surgeon factors including age, everyday risk-taking, self-belief in surgical ability and lower probability bias of anastomotic leak appear to exert an effect on decision-making in rectal surgery.

  9. A marketing science perspective on recognition-based heuristics (and the fast-and-frugal paradigm

    Directory of Open Access Journals (Sweden)

    John Hauser

    2011-07-01

    Full Text Available Marketing science seeks to prescribe better marketing strategies (advertising, product development, pricing, etc.. To do so we rely on models of consumer decisions grounded in empirical observations. Field experience suggests that recognition-based heuristics help consumers to choose which brands to consider and purchase in frequently-purchased categories, but other heuristics are more relevant in durable-goods categories. Screening with recognition is a rational screening rule when advertising is a signal of product quality, when observing other consumers makes it easy to learn decision rules, and when firms react to engineering-design constraints by offering brands such that a high-level on one product feature implies a low level on another product feature. Experience with applications and field experiments suggests four fruitful research topics: deciding how to decide (endogeneity, learning decision rules by self-reflection, risk reduction, and the difference between utility functions and decision rules. These challenges also pose methodological cautions.

  10. A Meta-Heuristic Applying for the Transportation of Wood Raw Material

    Directory of Open Access Journals (Sweden)

    Erhan Çalışkan

    2009-04-01

    Full Text Available Primary products in Turkish forestry are wood material. Thus, an operational organization is necessary to transport these main products to depots and then to the consumers without quality and volume loss. This organization starts from harvesting area in the stand and continues to roadside depots or ramps and to main depots and even to manufactures from there. The computer-assisted models, which aim to examine the optimum path in transportation, can be utilized in solving this quite complex problem. In this study, an evaluation has been performed in importance and current status of transporting wood material, classification of wood transportation, computer-assisted heuristic and meta-heuristic methods, and possibilities of using these methods in transportation of wood materials.

  11. Interim Report on Heuristics about Inspection Parameters: Updates to Heuristics Resulting from Refinement on Projects

    Science.gov (United States)

    Shull, Forrest; Seaman, Carolyn; Feldman, Raimund; Haingaertner, Ralf; Regardie, Myrna

    2008-01-01

    In 2008, we have continued analyzing the inspection data in an effort to better understand the applicability and effect of the inspection heuristics on inspection outcomes. Our research goals during this period are: 1. Investigate the effect of anomalies in the dataset (e.g. the very large meeting length values for some inspections) on our results 2. Investigate the effect of the heuristics on other inspection outcome variables (e.g. effort) 3. Investigate whether the recommended ranges can be modified to give inspection planners more flexibility without sacrificing effectiveness 4. Investigate possible refinements or modifications to the heuristics for specific subdomains (partitioned, e.g., by size, domain, or Center) This memo reports our results to date towards addressing these goals. In the next section, the first goal is addressed by describing the types of anomalies we have found in our dataset, how we have addressed them, and the effect of these changes on our previously reported results. In the following section, on "methodology", we describe the analyses we have conducted to address the other three goals and the results of these analyses are described in the "results" section. Finally, we conclude with future plans for continuing our investigation.

  12. Irrigation Water Quality for Leafy Crops: A Perspective of Risks and Potential Solutions

    Directory of Open Access Journals (Sweden)

    Ana Allende

    2015-07-01

    Full Text Available There is increasing evidence of the contribution of irrigation water in the contamination of produce leading to subsequent outbreaks of foodborne illness. This is a particular risk in the production of leafy vegetables that will be eaten raw without cooking. Retailers selling leafy vegetables are increasingly targeting zero-risk production systems and the associated requirements for irrigation water quality have become more stringent in regulations and quality assurance schemes (QAS followed by growers. Growers can identify water sources that are contaminated with potential pathogens through a monitoring regime and only use water free of pathogens, but the low prevalence of pathogens makes the use of faecal indicators, particularly E. coli, a more practical approach. Where growers have to utilise water sources of moderate quality, they can reduce the risk of contamination of the edible portion of the crop (i.e., the leaves by treating irrigation water before use through physical or chemical disinfection systems, or avoid contact between the leaves and irrigation water through the use of drip or furrow irrigation, or the use of hydroponic growing systems. This study gives an overview of the main problems in the production of leafy vegetables associated with irrigation water, including microbial risk and difficulties in water monitoring, compliance with evolving regulations and quality standards, and summarises the current alternatives available for growers to reduce microbial risks.

  13. Irrigation Water Quality for Leafy Crops: A Perspective of Risks and Potential Solutions

    Science.gov (United States)

    Allende, Ana; Monaghan, James

    2015-01-01

    There is increasing evidence of the contribution of irrigation water in the contamination of produce leading to subsequent outbreaks of foodborne illness. This is a particular risk in the production of leafy vegetables that will be eaten raw without cooking. Retailers selling leafy vegetables are increasingly targeting zero-risk production systems and the associated requirements for irrigation water quality have become more stringent in regulations and quality assurance schemes (QAS) followed by growers. Growers can identify water sources that are contaminated with potential pathogens through a monitoring regime and only use water free of pathogens, but the low prevalence of pathogens makes the use of faecal indicators, particularly E. coli, a more practical approach. Where growers have to utilise water sources of moderate quality, they can reduce the risk of contamination of the edible portion of the crop (i.e., the leaves) by treating irrigation water before use through physical or chemical disinfection systems, or avoid contact between the leaves and irrigation water through the use of drip or furrow irrigation, or the use of hydroponic growing systems. This study gives an overview of the main problems in the production of leafy vegetables associated with irrigation water, including microbial risk and difficulties in water monitoring, compliance with evolving regulations and quality standards, and summarises the current alternatives available for growers to reduce microbial risks. PMID:26151764

  14. Irrigation Water Quality for Leafy Crops: A Perspective of Risks and Potential Solutions.

    Science.gov (United States)

    Allende, Ana; Monaghan, James

    2015-07-03

    There is increasing evidence of the contribution of irrigation water in the contamination of produce leading to subsequent outbreaks of foodborne illness. This is a particular risk in the production of leafy vegetables that will be eaten raw without cooking. Retailers selling leafy vegetables are increasingly targeting zero-risk production systems and the associated requirements for irrigation water quality have become more stringent in regulations and quality assurance schemes (QAS) followed by growers. Growers can identify water sources that are contaminated with potential pathogens through a monitoring regime and only use water free of pathogens, but the low prevalence of pathogens makes the use of faecal indicators, particularly E. coli, a more practical approach. Where growers have to utilise water sources of moderate quality, they can reduce the risk of contamination of the edible portion of the crop (i.e., the leaves) by treating irrigation water before use through physical or chemical disinfection systems, or avoid contact between the leaves and irrigation water through the use of drip or furrow irrigation, or the use of hydroponic growing systems. This study gives an overview of the main problems in the production of leafy vegetables associated with irrigation water, including microbial risk and difficulties in water monitoring, compliance with evolving regulations and quality standards, and summarises the current alternatives available for growers to reduce microbial risks.

  15. Mixed Integer Programming and Heuristic Scheduling for Space Communication

    Science.gov (United States)

    Lee, Charles H.; Cheung, Kar-Ming

    2013-01-01

    Optimal planning and scheduling for a communication network was created where the nodes within the network are communicating at the highest possible rates while meeting the mission requirements and operational constraints. The planning and scheduling problem was formulated in the framework of Mixed Integer Programming (MIP) to introduce a special penalty function to convert the MIP problem into a continuous optimization problem, and to solve the constrained optimization problem using heuristic optimization. The communication network consists of space and ground assets with the link dynamics between any two assets varying with respect to time, distance, and telecom configurations. One asset could be communicating with another at very high data rates at one time, and at other times, communication is impossible, as the asset could be inaccessible from the network due to planetary occultation. Based on the network's geometric dynamics and link capabilities, the start time, end time, and link configuration of each view period are selected to maximize the communication efficiency within the network. Mathematical formulations for the constrained mixed integer optimization problem were derived, and efficient analytical and numerical techniques were developed to find the optimal solution. By setting up the problem using MIP, the search space for the optimization problem is reduced significantly, thereby speeding up the solution process. The ratio of the dimension of the traditional method over the proposed formulation is approximately an order N (single) to 2*N (arraying), where N is the number of receiving antennas of a node. By introducing a special penalty function, the MIP problem with non-differentiable cost function and nonlinear constraints can be converted into a continuous variable problem, whose solution is possible.

  16. The recognition heuristic: a review of theory and tests.

    Science.gov (United States)

    Pachur, Thorsten; Todd, Peter M; Gigerenzer, Gerd; Schooler, Lael J; Goldstein, Daniel G

    2011-01-01

    The recognition heuristic is a prime example of how, by exploiting a match between mind and environment, a simple mental strategy can lead to efficient decision making. The proposal of the heuristic initiated a debate about the processes underlying the use of recognition in decision making. We review research addressing four key aspects of the recognition heuristic: (a) that recognition is often an ecologically valid cue; (b) that people often follow recognition when making inferences; (c) that recognition supersedes further cue knowledge; (d) that its use can produce the less-is-more effect - the phenomenon that lesser states of recognition knowledge can lead to more accurate inferences than more complete states. After we contrast the recognition heuristic to other related concepts, including availability and fluency, we carve out, from the existing findings, some boundary conditions of the use of the recognition heuristic as well as key questions for future research. Moreover, we summarize developments concerning the connection of the recognition heuristic with memory models. We suggest that the recognition heuristic is used adaptively and that, compared to other cues, recognition seems to have a special status in decision making. Finally, we discuss how systematic ignorance is exploited in other cognitive mechanisms (e.g., estimation and preference).

  17. Cognitive load during route selection increases reliance on spatial heuristics.

    Science.gov (United States)

    Brunyé, Tad T; Martis, Shaina B; Taylor, Holly A

    2018-05-01

    Planning routes from maps involves perceiving the symbolic environment, identifying alternate routes and applying explicit strategies and implicit heuristics to select an option. Two implicit heuristics have received considerable attention, the southern route preference and initial segment strategy. This study tested a prediction from decision-making theory that increasing cognitive load during route planning will increase reliance on these heuristics. In two experiments, participants planned routes while under conditions of minimal (0-back) or high (2-back) working memory load. In Experiment 1, we examined how memory load impacts the southern route heuristic. In Experiment 2, we examined how memory load impacts the initial segment heuristic. Results replicated earlier results demonstrating a southern route preference (Experiment 1) and initial segment strategy (Experiment 2) and further demonstrated that evidence for heuristic reliance is more likely under conditions of concurrent working memory load. Furthermore, the extent to which participants maintained efficient route selection latencies in the 2-back condition predicted the magnitude of this effect. Together, results demonstrate that working memory load increases the application of heuristics during spatial decision making, particularly when participants attempt to maintain quick decisions while managing concurrent task demands.

  18. The Recognition Heuristic: A Review of Theory and Tests

    Directory of Open Access Journals (Sweden)

    Thorsten ePachur

    2011-07-01

    Full Text Available The recognition heuristic is a prime example of how, by exploiting a match between mind and environment, a simple mental strategy can lead to efficient decision making. The proposal of the heuristic initiated a debate about the processes underlying the use of recognition in decision making. We review research addressing four key aspects of the recognition heuristic: (a that recognition is often an ecologically valid cue; (b that people often follow recognition when making inferences; (c that recognition supersedes further cue knowledge; (d that its use can produce the less-is-more effect—the phenomenon that lesser states of recognition knowledge can lead to more accurate inferences than more complete states. After we contrast the recognition heuristic to other related concepts, including availability and fluency, we carve out, from the existing findings, some boundary conditions of the use of the recognition heuristic as well as key questions for future research. Moreover, we summarize developments concerning the connection of the recognition heuristic with memory models. We suggest that the recognition heuristic is used adaptively and that, compared to other cues, recognition seems to have a special status in decision making. Finally, we discuss how systematic ignorance is exploited in other cognitive mechanisms (e.g., estimation and preference.

  19. The Recognition Heuristic: A Review of Theory and Tests

    Science.gov (United States)

    Pachur, Thorsten; Todd, Peter M.; Gigerenzer, Gerd; Schooler, Lael J.; Goldstein, Daniel G.

    2011-01-01

    The recognition heuristic is a prime example of how, by exploiting a match between mind and environment, a simple mental strategy can lead to efficient decision making. The proposal of the heuristic initiated a debate about the processes underlying the use of recognition in decision making. We review research addressing four key aspects of the recognition heuristic: (a) that recognition is often an ecologically valid cue; (b) that people often follow recognition when making inferences; (c) that recognition supersedes further cue knowledge; (d) that its use can produce the less-is-more effect – the phenomenon that lesser states of recognition knowledge can lead to more accurate inferences than more complete states. After we contrast the recognition heuristic to other related concepts, including availability and fluency, we carve out, from the existing findings, some boundary conditions of the use of the recognition heuristic as well as key questions for future research. Moreover, we summarize developments concerning the connection of the recognition heuristic with memory models. We suggest that the recognition heuristic is used adaptively and that, compared to other cues, recognition seems to have a special status in decision making. Finally, we discuss how systematic ignorance is exploited in other cognitive mechanisms (e.g., estimation and preference). PMID:21779266

  20. Heuristics, biases and traps in managerial decision making

    Directory of Open Access Journals (Sweden)

    Peter Gál

    2013-01-01

    Full Text Available The aim of the paper is to demonstrate the impact of heuristics, biases and psychological traps on the decision making. Heuristics are unconscious routines people use to cope with the complexity inherent in most decision situations. They serve as mental shortcuts that help people to simplify and structure the information encountered in the world. These heuristics could be quite useful in some situations, while in others they can lead to severe and systematic errors, based on significant deviations from the fundamental principles of statistics, probability and sound judgment. This paper focuses on illustrating the existence of the anchoring, availability, and representativeness heuristics, originally described by Tversky & Kahneman in the early 1970’s. The anchoring heuristic is a tendency to focus on the initial information, estimate or perception (even random or irrelevant number as a starting point. People tend to give disproportionate weight to the initial information they receive. The availability heuristic explains why highly imaginable or vivid information have a disproportionate effect on people’s decisions. The representativeness heuristic causes that people rely on highly specific scenarios, ignore base rates, draw conclusions based on small samples and neglect scope. Mentioned phenomena are illustrated and supported by evidence based on the statistical analysis of the results of a questionnaire.

  1. Comparative study of heuristic evaluation and usability testing methods.

    Science.gov (United States)

    Thyvalikakath, Thankam Paul; Monaco, Valerie; Thambuganipalle, Himabindu; Schleyer, Titus

    2009-01-01

    Usability methods, such as heuristic evaluation, cognitive walk-throughs and user testing, are increasingly used to evaluate and improve the design of clinical software applications. There is still some uncertainty, however, as to how those methods can be used to support the development process and evaluation in the most meaningful manner. In this study, we compared the results of a heuristic evaluation with those of formal user tests in order to determine which usability problems were detected by both methods. We conducted heuristic evaluation and usability testing on four major commercial dental computer-based patient records (CPRs), which together cover 80% of the market for chairside computer systems among general dentists. Both methods yielded strong evidence that the dental CPRs have significant usability problems. An average of 50% of empirically-determined usability problems were identified by the preceding heuristic evaluation. Some statements of heuristic violations were specific enough to precisely identify the actual usability problem that study participants encountered. Other violations were less specific, but still manifested themselves in usability problems and poor task outcomes. In this study, heuristic evaluation identified a significant portion of problems found during usability testing. While we make no assumptions about the generalizability of the results to other domains and software systems, heuristic evaluation may, under certain circumstances, be a useful tool to determine design problems early in the development cycle.

  2. Kernel method for air quality modelling. II. Comparison with analytic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lorimer, G S; Ross, D G

    1986-01-01

    The performance of Lorimer's (1986) kernel method for solving the advection-diffusion equation is tested for instantaneous and continuous emissions into a variety of model atmospheres. Analytical solutions are available for comparison in each case. The results indicate that a modest minicomputer is quite adequate for obtaining satisfactory precision even for the most trying test performed here, which involves a diffusivity tensor and wind speed which are nonlinear functions of the height above ground. Simulations of the same cases by the particle-in-cell technique are found to provide substantially lower accuracy even when use is made of greater computer resources.

  3. Expanding Continuous Quality Improvement Capacity in the Medical Intensive Care Unit: Prehealth Volunteers as a Solution.

    Science.gov (United States)

    Priest, Kelsey C; Lobingier, Hannah; McCully, Nancy; Lombard, Jackie; Hansen, Mark; Uchiyama, Makoto; Hagg, Daniel S

    2016-01-01

    Health care delivery systems are challenged to support the increasing demands for improving patient safety, satisfaction, and outcomes. Limited resources and staffing are common barriers for making significant and sustained improvements. At Oregon Health & Science University, the medical intensive care unit (MICU) leadership team faced internal capacity limitations for conducting continuous quality improvement, specifically for the implementation and evaluation of the mobility portion of an evidence-based care bundle. The MICU team successfully addressed this capacity challenge using the person power of prehealth volunteers. In the first year of the project, 52 trained volunteers executed an evidence-based mobility intervention for 305 critically ill patients, conducting more than 200 000 exercise repetitions. The volunteers contributed to real-time evaluation of the project, with the collection of approximately 26 950 process measure data points. Prehealth volunteers are an untapped resource for effectively expanding internal continuous quality improvement capacity in the MICU and beyond.

  4. A Slicing Tree Representation and QCP-Model-Based Heuristic Algorithm for the Unequal-Area Block Facility Layout Problem

    Directory of Open Access Journals (Sweden)

    Mei-Shiang Chang

    2013-01-01

    Full Text Available The facility layout problem is a typical combinational optimization problem. In this research, a slicing tree representation and a quadratically constrained program model are combined with harmony search to develop a heuristic method for solving the unequal-area block layout problem. Because of characteristics of slicing tree structure, we propose a regional structure of harmony memory to memorize facility layout solutions and two kinds of harmony improvisation to enhance global search ability of the proposed heuristic method. The proposed harmony search based heuristic is tested on 10 well-known unequal-area facility layout problems from the literature. The results are compared with the previously best-known solutions obtained by genetic algorithm, tabu search, and ant system as well as exact methods. For problems O7, O9, vC10Ra, M11*, and Nug12, new best solutions are found. For other problems, the proposed approach can find solutions that are very similar to previous best-known solutions.

  5. Poster - Thur Eve - 54: A software solution for ongoing DVH quality assurance in radiation therapy.

    Science.gov (United States)

    Annis, S-L; Zeng, G; Wu, X; Macpherson, M

    2012-07-01

    A program has been developed in MATLAB for use in quality assurance of treatment planning of radiation therapy. It analyzes patient DVH files and compiles dose volume data for review, trending, comparison and analysis. Patient DVH files are exported from the Eclipse treatment planning system and saved according to treatment sites and date. Currently analysis is available for 4 treatment sites; Prostate, Prostate Bed, Lung, and Upper GI, with two functions for data report and analysis: patient-specific and organ-specific. The patient-specific function loads one patient DVH file and reports the user-specified dose volume data of organs and targets. These data can be compiled to an external file for a third party analysis. The organ-specific function extracts a requested dose volume of an organ from the DVH files of a patient group and reports the statistics over this population. A graphical user interface is utilized to select clinical sites, function and structures, and input user's requests. We have implemented this program in planning quality assurance at our center. The program has tracked the dosimetric improvement in GU sites after VMAT was implemented clinically. It has generated dose volume statistics for different groups of patients associated with technique or time range. This program allows reporting and statistical analysis of DVH files. It is an efficient tool for the planning quality control in radiation therapy. © 2012 American Association of Physicists in Medicine.

  6. Exploring trade-offs between VMAT dose quality and delivery efficiency using a network optimization approach

    International Nuclear Information System (INIS)

    Salari, Ehsan; Craft, David; Wala, Jeremiah

    2012-01-01

    To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called vmerge, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. vmerge begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the ‘ideal’ dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard vmerge algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the

  7. Exploring trade-offs between VMAT dose quality and delivery efficiency using a network optimization approach.

    Science.gov (United States)

    Salari, Ehsan; Wala, Jeremiah; Craft, David

    2012-09-07

    To formulate and solve the fluence-map merging procedure of the recently-published VMAT treatment-plan optimization method, called VMERGE, as a bi-criteria optimization problem. Using an exact merging method rather than the previously-used heuristic, we are able to better characterize the trade-off between the delivery efficiency and dose quality. VMERGE begins with a solution of the fluence-map optimization problem with 180 equi-spaced beams that yields the 'ideal' dose distribution. Neighboring fluence maps are then successively merged, meaning that they are added together and delivered as a single map. The merging process improves the delivery efficiency at the expense of deviating from the initial high-quality dose distribution. We replace the original merging heuristic by considering the merging problem as a discrete bi-criteria optimization problem with the objectives of maximizing the treatment efficiency and minimizing the deviation from the ideal dose. We formulate this using a network-flow model that represents the merging problem. Since the problem is discrete and thus non-convex, we employ a customized box algorithm to characterize the Pareto frontier. The Pareto frontier is then used as a benchmark to evaluate the performance of the standard VMERGE algorithm as well as two other similar heuristics. We test the exact and heuristic merging approaches on a pancreas and a prostate cancer case. For both cases, the shape of the Pareto frontier suggests that starting from a high-quality plan, we can obtain efficient VMAT plans through merging neighboring fluence maps without substantially deviating from the initial dose distribution. The trade-off curves obtained by the various heuristics are contrasted and shown to all be equally capable of initial plan simplifications, but to deviate in quality for more drastic efficiency improvements. This work presents a network optimization approach to the merging problem. Contrasting the trade-off curves of the merging

  8. A Dynamic and Heuristic Phase Balancing Method for LV Feeders

    Directory of Open Access Journals (Sweden)

    Samad Taghipour Boroujeni

    2016-01-01

    Full Text Available Due to the single-phase loads and their stochastic behavior, the current in the distribution feeders is not balanced. In addition, the single-phase loads are located in different positions along the LV feeders. So the amount of the unbalanced load and its location affect the feeder losses. An unbalanced load causes the feeder losses and the voltage drop. Because of time-varying behavior of the single-phase loads, phase balancing is a dynamic and combinatorial problem. In this research, a heuristic and dynamic solution for the phase balancing of the LV feeders is proposed. In this method, it is supposed that the loads’ tie could be connected to all phases through a three-phase switch. The aim of the proposed method is to make the feeder conditions as balanced as possible. The amount and the location of single-phase loads are considered in the proposed phase balancing method. Since the proposed method needs no communication interface or no remote controller, it is inexpensive, simple, practical, and robust. Applying this method provides a distributed and dynamic phase balancing control. In addition, the feasibility of reducing the used switches is investigated. The ability of the proposed method in the phase balancing of the LV feeders is approved by carrying out some simulations.

  9. Heuristic Method for Decision-Making in Common Scheduling Problems

    Directory of Open Access Journals (Sweden)

    Edyta Kucharska

    2017-10-01

    Full Text Available The aim of the paper is to present a heuristic method for decision-making regarding an NP-hard scheduling problem with limitations related to tasks and the resources dependent on the current state of the process. The presented approach is based on the algebraic-logical meta-model (ALMM, which enables making collective decisions in successive process stages, not separately for individual objects or executors. Moreover, taking into account the limitations of the problem, it involves constructing only an acceptable solution and significantly reduces the amount of calculations. A general algorithm based on the presented method is composed of the following elements: preliminary analysis of the problem, techniques for the choice of decision at a given state, the pruning non-perspective trajectory, selection technique of the initial state for the trajectory final part, and the trajectory generation parameters modification. The paper includes applications of the presented approach to scheduling problems on unrelated parallel machines with a deadline and machine setup time dependent on the process state, where the relationship between tasks is defined by the graph. The article also presents the results of computational experiments.

  10. User Interface Problems of a Nationwide Inpatient Information System: A Heuristic Evaluation.

    Science.gov (United States)

    Atashi, Alireza; Khajouei, Reza; Azizi, Amirabbas; Dadashi, Ali

    2016-01-01

    While studies have shown that usability evaluation could uncover many design problems of health information systems, the usability of health information systems in developing countries using their native language is poorly studied. The objective of this study was to evaluate the usability of a nationwide inpatient information system used in many academic hospitals in Iran. Three trained usability evaluators independently evaluated the system using Nielsen's 10 usability heuristics. The evaluators combined identified problems in a single list and independently rated the severity of the problems. We statistically compared the number and severity of problems identified by HIS experienced and non-experienced evaluators. A total of 158 usability problems were identified. After removing duplications 99 unique problems were left. The highest mismatch with usability principles was related to "Consistency and standards" heuristic (25%) and the lowest related to "Flexibility and efficiency of use" (4%). The average severity of problems ranged from 2.4 (Major problem) to 3.3 (Catastrophe problem). The experienced evaluator with HIS identified significantly more problems and gave higher severities to problems (pusers' and patients' time, increase errors and finally threaten patient's safety. Many of them can be fixed with simple redesign solutions such as using clear labels and better layouts. This study suggests conducting further studies to confirm the findings concerning effect of evaluator experience on the results of Heuristic Evaluation.

  11. Applied tagmemics: A heuristic approach to the use of graphic aids in technical writing

    Science.gov (United States)

    Brownlee, P. P.; Kirtz, M. K.

    1981-01-01

    In technical report writing, two needs which must be met if reports are to be useable by an audience are the language needs and the technical needs of that particular audience. A heuristic analysis helps to decide the most suitable format for information; that is, whether the information should be presented verbally or visually. The report writing process should be seen as an organic whole which can be divided and subdivided according to the writer's purpose, but which always functions as a totality. The tagmemic heuristic, because it itself follows a process of deconstructing and reconstructing information, lends itself to being a useful approach to the teaching of technical writing. By applying the abstract questions this heuristic asks to specific parts of the report. The language and technical needs of the audience are analyzed by examining the viability of the solution within the givens of the corporate structure, and by deciding which graphic or verbal format will best suit the writer's purpose. By following such a method, answers which are both specific and thorough in their range of application are found.

  12. Analysis of Heuristic Uniform Theory of Diffraction Coefficients for Electromagnetic Scattering Prediction

    Directory of Open Access Journals (Sweden)

    Diego Tami

    2018-01-01

    Full Text Available We discuss three sets of heuristic coefficients used in uniform theory of diffraction (UTD to characterize the electromagnetic scattering in realistic urban scenarios and canonical examples of diffraction by lossy conducting wedges using the three sets of heuristic coefficients and the Malyuzhinets solution as reference model. We compare not only the results of the canonical models but also their implementation in real outdoor scenarios. To predict the coverage of mobile networks, we used propagation models for outdoor environments by using a 3D ray-tracing model based on a brute-force algorithm for ray launching and a propagation model based on image theory. To evaluate each set of coefficients, we analyzed the mean and standard deviation of the absolute error between estimates and measured data in Ottawa, Canada; Valencia, Spain; and Cali, Colombia. Finally, we discuss the path loss prediction for each set of heuristic UTD coefficients in outdoor environment, as well as the comparison with the canonical results.

  13. Energetic solutions of Rock Sandpipers to harsh winter conditions rely on prey quality

    Science.gov (United States)

    Ruthrauff, Daniel R.; Dekinga, Anne; Gill, Robert E.; Piersma, Theunis

    2018-01-01

    Rock Sandpipers Calidris ptilocnemis have the most northerly non-breeding distribution of any shorebird in the Pacific Basin (upper Cook Inlet, Alaska; 61°N, 151°W). In terms of freezing temperatures, persistent winds and pervasive ice, this site is the harshest used by shorebirds during winter. We integrated physiological, metabolic, behavioural and environmental aspects of the non-breeding ecology of Rock Sandpipers at the northern extent of their range to determine the relative importance of these factors in facilitating their unique non-breeding ecology. Not surprisingly, estimated daily energetic demands were greatest during January, the coldest period of winter. These estimates were greatest for foraging birds, and exceeded basal metabolic rates by a factor of 6.5, a scope of increase that approaches the maximum sustained rate of energetic output by shorebirds during periods of migration, but far exceeds these periods in duration. We assessed the quality of their primary prey, the bivalve Macoma balthica, to determine the daily foraging duration required by Rock Sandpipers to satisfy such energetic demands. Based on size-specific estimates of M. balthica quality, Rock Sandpipers require over 13 h/day of foraging time in upper Cook Inlet in January, even when feeding on the highest quality prey. This range approaches the average daily duration of mudflat availability in this region (c. 18 h), a maximum value that annually decreases due to the accumulation of shore-fast ice. Rock Sandpipers are likely to maximize access to foraging sites by following the exposure of ice-free mudflats across the upper Cook Inlet region and by selecting smaller, higher quality M. balthica to minimize foraging times. Ultimately, this unusual non-breeding ecology relies on the high quality of their prey resources. Compared with other sites across their range, M. balthica from upper Cook Inlet have relatively light shells, potentially the result of the region

  14. On the Importance of Elimination Heuristics in Lazy Propagation

    DEFF Research Database (Denmark)

    Madsen, Anders Læsø; Butz, Cory J.

    2012-01-01

    elimination orders on-line. This paper considers the importance of elimination heuristics in LP when using Variable Elimination (VE) as the message and single marginal computation algorithm. It considers well-known cost measures for selecting the next variable to eliminate and a new cost measure....... The empirical evaluation examines dierent heuristics as well as sequences of cost measures, and was conducted on real-world and randomly generated Bayesian networks. The results show that for most cases performance is robust relative to the cost measure used and in some cases the elimination heuristic can have...

  15. Solving Large Clustering Problems with Meta-Heuristic Search

    DEFF Research Database (Denmark)

    Turkensteen, Marcel; Andersen, Kim Allan; Bang-Jensen, Jørgen

    In Clustering Problems, groups of similar subjects are to be retrieved from data sets. In this paper, Clustering Problems with the frequently used Minimum Sum-of-Squares Criterion are solved using meta-heuristic search. Tabu search has proved to be a successful methodology for solving optimization...... problems, but applications to large clustering problems are rare. The simulated annealing heuristic has mainly been applied to relatively small instances. In this paper, we implement tabu search and simulated annealing approaches and compare them to the commonly used k-means approach. We find that the meta-heuristic...

  16. Motor heuristics and embodied choices: how to choose and act.

    Science.gov (United States)

    Raab, Markus

    2017-08-01

    Human performance requires choosing what to do and how to do it. The goal of this theoretical contribution is to advance understanding of how the motor and cognitive components of choices are intertwined. From a holistic perspective I extend simple heuristics that have been tested in cognitive tasks to motor tasks, coining the term motor heuristics. Similarly I extend the concept of embodied cognition, that has been tested in simple sensorimotor processes changing decisions, to complex sport behavior coining the term embodied choices. Thus both motor heuristics and embodied choices explain complex behavior such as studied in sport and exercise psychology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Heuristic Portfolio Trading Rules with Capital Gain Taxes

    DEFF Research Database (Denmark)

    Fischer, Marcel; Gallmeyer, Michael

    2016-01-01

    We study the out-of-sample performance of portfolio trading strategies used when an investor faces capital gain taxation and proportional transaction costs. Overlaying simple tax trading heuristics on trading strategies improves out-of-sample performance. For medium to large transaction costs......, no trading strategy can outperform a 1/N trading strategy augmented with a tax heuristic, not even the most tax and transaction cost-efficient buy-and-hold strategy. Overall, the best strategy is 1/N augmented with a heuristic that allows for a fixed deviation in absolute portfolio weights. Our results thus...... show that the best trading strategies balance diversification considerations and tax considerations....

  18. The beauty of simple models: Themes in recognition heuristic research

    Directory of Open Access Journals (Sweden)

    Daniel G. Goldstein

    2011-07-01

    Full Text Available The advantage of models that do not use flexible parameters is that one can precisely show to what degree they predict behavior, and in what situations. In three issues of this journal, the recognition heuristic has been examined carefully from many points of view. We comment here on four themes, the use of optimization models to understand the rationality of heuristics, the generalization of the recognition input beyond a binary judgment, new conditions for less-is-more effects, and the importance of specifying boundary conditions for cognitive heuristics.

  19. Parameter estimation with bio-inspired meta-heuristic optimization: modeling the dynamics of endocytosis

    Directory of Open Access Journals (Sweden)

    Tashkova Katerina

    2011-10-01

    Full Text Available Abstract Background We address the task of parameter estimation in models of the dynamics of biological systems based on ordinary differential equations (ODEs from measured data, where the models are typically non-linear and have many parameters, the measurements are imperfect due to noise, and the studied system can often be only partially observed. A representative task is to estimate the parameters in a model of the dynamics of endocytosis, i.e., endosome maturation, reflected in a cut-out switch transition between the Rab5 and Rab7 domain protein concentrations, from experimental measurements of these concentrations. The general parameter estimation task and the specific instance considered here are challenging optimization problems, calling for the use of advanced meta-heuristic optimization methods, such as evolutionary or swarm-based methods. Results We apply three global-search meta-heuristic algorithms for numerical optimization, i.e., differential ant-stigmergy algorithm (DASA, particle-swarm optimization (PSO, and differential evolution (DE, as well as a local-search derivative-based algorithm 717 (A717 to the task of estimating parameters in ODEs. We evaluate their performance on the considered representative task along a number of metrics, including the quality of reconstructing the system output and the complete dynamics, as well as the speed of convergence, both on real-experimental data and on artificial pseudo-experimental data with varying amounts of noise. We compare the four optimization methods under a range of observation scenarios, where data of different completeness and accuracy of interpretation are given as input. Conclusions Overall, the global meta-heuristic methods (DASA, PSO, and DE clearly and significantly outperform the local derivative-based method (A717. Among the three meta-heuristics, differential evolution (DE performs best in terms of the objective function, i.e., reconstructing the output, and in terms of

  20. Parameter estimation with bio-inspired meta-heuristic optimization: modeling the dynamics of endocytosis.

    Science.gov (United States)

    Tashkova, Katerina; Korošec, Peter; Silc, Jurij; Todorovski, Ljupčo; Džeroski, Sašo

    2011-10-11

    We address the task of parameter estimation in models of the dynamics of biological systems based on ordinary differential equations (ODEs) from measured data, where the models are typically non-linear and have many parameters, the measurements are imperfect due to noise, and the studied system can often be only partially observed. A representative task is to estimate the parameters in a model of the dynamics of endocytosis, i.e., endosome maturation, reflected in a cut-out switch transition between the Rab5 and Rab7 domain protein concentrations, from experimental measurements of these concentrations. The general parameter estimation task and the specific instance considered here are challenging optimization problems, calling for the use of advanced meta-heuristic optimization methods, such as evolutionary or swarm-based methods. We apply three global-search meta-heuristic algorithms for numerical optimization, i.e., differential ant-stigmergy algorithm (DASA), particle-swarm optimization (PSO), and differential evolution (DE), as well as a local-search derivative-based algorithm 717 (A717) to the task of estimating parameters in ODEs. We evaluate their performance on the considered representative task along a number of metrics, including the quality of reconstructing the system output and the complete dynamics, as well as the speed of convergence, both on real-experimental data and on artificial pseudo-experimental data with varying amounts of noise. We compare the four optimization methods under a range of observation scenarios, where data of different completeness and accuracy of interpretation are given as input. Overall, the global meta-heuristic methods (DASA, PSO, and DE) clearly and significantly outperform the local derivative-based method (A717). Among the three meta-heuristics, differential evolution (DE) performs best in terms of the objective function, i.e., reconstructing the output, and in terms of convergence. These results hold for both real and

  1. Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Vilathgamuwa, D. M.; Loh, Poh Chiang

    2009-01-01

    Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time......-stage buck-boost inverter, recently proposed Z-source inverter (ZSI) is a good candidate for future DG systems. This paper presents a controller design for a ZSI-based DG system to improve power quality of distribution systems. The proposed control method is tested with simulation results obtained using...

  2. Cloud infrastructure for providing tools as a service: quality attributes and potential solutions

    DEFF Research Database (Denmark)

    Chauhan, Muhammad Aufeef; Ali Babar, Muhammad

    2012-01-01

    Cloud computing is being increasingly adopted in various domains for providing on-demand infrastructure and Software as a service (SaaS) by leveraging the utility computing model and virtualization technologies. One of the domains, where cloud computing is expected to gain huge traction is Global...... Software Development (GSD) that has emerged as a popular software development model. Despite several promised benefits, GSD is characterized by not only technical issues but also the complexities associated with its processes. One of the key challenges of GSD is to provide appropriate tools more...... efficiently and cost-effectively. Moreover, variations in tools available/used by different GSD team members can also pose challenges. We assert that providing Tools as a Service (TaaS) to GSD teams through a cloud-based infrastructure can be a promising solution to address the tools related challenges in GSD...

  3. Effect of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye.

    Science.gov (United States)

    Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Oie, Yoshinori; Soma, Takeshi; Tsujikawa, Motokazu; Watanabe, Hitoshi; Nishida, Kohji

    2014-12-01

    To investigate the short- and long-term effects of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye. Sixteen eyes in 16 patients with mild or moderate aqueous-deficient dry eye were treated with 3% diquafosol ophthalmic solution. Ocular higher-order aberrations (HOAs) were measured with a wavefront sensor before and at 15 min after diquafosol instillation at the baseline visit and at 4 weeks after treatment initiation. Dry eye symptoms, tear break-up time (BUT), corneal/conjunctival fluorescein staining and Schirmer's test were also evaluated before and after treatment with diquafosol. Treatment with diquafosol ophthalmic solution significantly improved dry eye symptoms, corneal staining and BUT. Compared with mean total HOAs at baseline (0.180 ± 0.06 μm), those at 4 weeks after treatment significantly decreased (0.148 ± 0.039 μm; p = 0.035), whereas those 15 min after diquafosol instillation at the baseline visit did not change significantly (0.170 ± 0.049 μm; p = 0.279). Although no significant change in HOAs was observed as a short-term effect of a single-drop instillation of diquafosol, long-term use of diquafosol to treat aqueous-deficient dry eye reduced HOAs as well as improved corneal epithelial damage and tear film stability. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  4. Owning solutions: a collaborative model to improve quality in hospital care for Aboriginal Australians.

    Science.gov (United States)

    Durey, Angela; Wynaden, Dianne; Thompson, Sandra C; Davidson, Patricia M; Bessarab, Dawn; Katzenellenbogen, Judith M

    2012-06-01

    Well-documented health disparities between Aboriginal and Torres Strait Islander (hereafter referred to as Aboriginal) and non-Aboriginal Australians are underpinned by complex historical and social factors. The effects of colonisation including racism continue to impact negatively on Aboriginal health outcomes, despite being under-recognised and under-reported. Many Aboriginal people find hospitals unwelcoming and are reluctant to attend for diagnosis and treatment, particularly with few Aboriginal health professionals employed on these facilities. In this paper, scientific literature and reports on Aboriginal health-care, methodology and cross-cultural education are reviewed to inform a collaborative model of hospital-based organisational change. The paper proposes a collaborative model of care to improve health service delivery by building capacity in Aboriginal and non-Aboriginal personnel by recruiting more Aboriginal health professionals, increasing knowledge and skills to establish good relationships between non-Aboriginal care providers and Aboriginal patients and their families, delivering quality care that is respectful of culture and improving Aboriginal health outcomes. A key element of model design, implementation and evaluation is critical reflection on barriers and facilitators to providing respectful and culturally safe quality care at systemic, interpersonal and patient/family-centred levels. Nurses are central to addressing the current state of inequity and are pivotal change agents within the proposed model. © 2011 Blackwell Publishing Ltd.

  5. Economic tour package model using heuristic

    Science.gov (United States)

    Rahman, Syariza Abdul; Benjamin, Aida Mauziah; Bakar, Engku Muhammad Nazri Engku Abu

    2014-07-01

    A tour-package is a prearranged tour that includes products and services such as food, activities, accommodation, and transportation, which are sold at a single price. Since the competitiveness within tourism industry is very high, many of the tour agents try to provide attractive tour-packages in order to meet tourist satisfaction as much as possible. Some of the criteria that are considered by the tourist are the number of places to be visited and the cost of the tour-packages. Previous studies indicate that tourists tend to choose economical tour-packages and aiming to visit as many places as they can cover. Thus, this study proposed tour-package model using heuristic approach. The aim is to find economical tour-packages and at the same time to propose as many places as possible to be visited by tourist in a given geographical area particularly in Langkawi Island. The proposed model considers only one starting point where the tour starts and ends at an identified hotel. This study covers 31 most attractive places in Langkawi Island from various categories of tourist attractions. Besides, the allocation of period for lunch and dinner are included in the proposed itineraries where it covers 11 popular restaurants around Langkawi Island. In developing the itinerary, the proposed heuristic approach considers time window for each site (hotel/restaurant/place) so that it represents real world implementation. We present three itineraries with different time constraints (1-day, 2-day and 3-day tour-package). The aim of economic model is to minimize the tour-package cost as much as possible by considering entrance fee of each visited place. We compare the proposed model with our uneconomic model from our previous study. The uneconomic model has no limitation to the cost with the aim to maximize the number of places to be visited. Comparison between the uneconomic and economic itinerary has shown that the proposed model have successfully achieved the objective that

  6. Modelling antibody side chain conformations using heuristic database search.

    Science.gov (United States)

    Ritchie, D W; Kemp, G J

    1997-01-01

    We have developed a knowledge-based system which models the side chain conformations of residues in the variable domains of antibody Fv fragments. The system is written in Prolog and uses an object-oriented database of aligned antibody structures in conjunction with a side chain rotamer library. The antibody database provides 3-dimensional clusters of side chain conformations which can be copied en masse into the model structure. The object-oriented database architecture facilitates a navigational style of database access, necessary to assemble side chains clusters. Around 60% of the model is built using side chain clusters and this eliminates much of the combinatorial complexity associated with many other side chain placement algorithms. Construction and placement of side chain clusters is guided by a heuristic cost function based on a simple model of side chain packing interactions. Even with a simple model, we find that a large proportion of side chain conformations are modelled accurately. We expect our approach could be used with other homologous protein families, in addition to antibodies, both to improve the quality of model structures and to give a "smart start" to the side chain placement problem.

  7. A Heuristic Model for Supporting Users’ Decision-Making in Privacy Disclosure for Recommendation

    Directory of Open Access Journals (Sweden)

    Hongchen Wu

    2018-01-01

    Full Text Available Privacy issues have become a major concern in the web of resource sharing, and users often have difficulty managing their information disclosure in the context of high-quality experiences from social media and Internet of Things. Recent studies have shown that users’ disclosure decisions may be influenced by heuristics from the crowds, leading to inconsistency in the disclosure volumes and reduction of the prediction accuracy. Therefore, an analysis of why this influence occurs and how to optimize the user experience is highly important. We propose a novel heuristic model that defines the data structures of items and participants in social media, utilizes a modified decision-tree classifier that can predict participants’ disclosures, and puts forward a correlation analysis for detecting disclosure inconsistences. The heuristic model is applied to real-time dataset to evaluate the behavioral effects. Decision-tree classifier and correlation analysis indeed prove that some participants’ behaviors in information disclosures became decreasingly correlated during item requesting. Participants can be “persuaded” to change their disclosure behaviors, and the users’ answers to the mildly sensitive items tend to be more variable and less predictable. Using this approach, recommender systems in social media can thus know the users better and provide service with higher prediction accuracy.

  8. Color waves : a simple heuristic for choosing false colors

    NARCIS (Netherlands)

    Overveld, van C.W.A.M.

    1997-01-01

    A simple heuristic is presented for choosing false colors for visualizing scalar functions on two-dimensional domains. The color scheme allows inspection of the function on several length scales simultanously.

  9. Expanding the Possibilities of AIS Data with Heuristics

    Directory of Open Access Journals (Sweden)

    Bjørnar Brende Smestad

    2017-06-01

    Full Text Available Automatic Identification System (AIS is primarily used as a tracking system for ships, but with the launch of satellites to collect these data, new and previously untested possibilities are emerging. This paper presents the development of heuristics for establishing the specific ship type using information retrieved from AIS data alone. These heuristics expand the possibilities of AIS data, as the specific ship type is vital for several transportation research cases, such as emission analyses of ship traffic and studies on slow steaming. The presented method for developing heuristics can be used for a wider range of vessels. These heuristics may form the basis of large-scale studies on ship traffic using AIS data when it is not feasible or desirable to use commercial ship data registers.

  10. Complex Chemical Reaction Networks from Heuristics-Aided Quantum Chemistry.

    Science.gov (United States)

    Rappoport, Dmitrij; Galvin, Cooper J; Zubarev, Dmitry Yu; Aspuru-Guzik, Alán

    2014-03-11

    While structures and reactivities of many small molecules can be computed efficiently and accurately using quantum chemical methods, heuristic approaches remain essential for modeling complex structures and large-scale chemical systems. Here, we present a heuristics-aided quantum chemical methodology applicable to complex chemical reaction networks such as those arising in cell metabolism and prebiotic chemistry. Chemical heuristics offer an expedient way of traversing high-dimensional reactive potential energy surfaces and are combined here with quantum chemical structure optimizations, which yield the structures and energies of the reaction intermediates and products. Application of heuristics-aided quantum chemical methodology to the formose reaction reproduces the experimentally observed reaction products, major reaction pathways, and autocatalytic cycles.

  11. The priority heuristic: making choices without trade-offs.

    Science.gov (United States)

    Brandstätter, Eduard; Gigerenzer, Gerd; Hertwig, Ralph

    2006-04-01

    Bernoulli's framework of expected utility serves as a model for various psychological processes, including motivation, moral sense, attitudes, and decision making. To account for evidence at variance with expected utility, the authors generalize the framework of fast and frugal heuristics from inferences to preferences. The priority heuristic predicts (a) the Allais paradox, (b) risk aversion for gains if probabilities are high, (c) risk seeking for gains if probabilities are low (e.g., lottery tickets), (d) risk aversion for losses if probabilities are low (e.g., buying insurance), (e) risk seeking for losses if probabilities are high, (f) the certainty effect, (g) the possibility effect, and (h) intransitivities. The authors test how accurately the heuristic predicts people's choices, compared with previously proposed heuristics and 3 modifications of expected utility theory: security-potential/aspiration theory, transfer-of-attention-exchange model, and cumulative prospect theory. ((c) 2006 APA, all rights reserved).

  12. Heuristic and algorithmic processing in English, mathematics, and science education.

    Science.gov (United States)

    Sharps, Matthew J; Hess, Adam B; Price-Sharps, Jana L; Teh, Jane

    2008-01-01

    Many college students experience difficulties in basic academic skills. Recent research suggests that much of this difficulty may lie in heuristic competency--the ability to use and successfully manage general cognitive strategies. In the present study, the authors evaluated this possibility. They compared participants' performance on a practice California Basic Educational Skills Test and on a series of questions in the natural sciences with heuristic and algorithmic performance on a series of mathematics and reading comprehension exercises. Heuristic competency in mathematics was associated with better scores in science and mathematics. Verbal and algorithmic skills were associated with better reading comprehension. These results indicate the importance of including heuristic training in educational contexts and highlight the importance of a relatively domain-specific approach to questions of cognition in higher education.

  13. The Priority Heuristic: Making Choices Without Trade-Offs

    Science.gov (United States)

    Brandstätter, Eduard; Gigerenzer, Gerd; Hertwig, Ralph

    2010-01-01

    Bernoulli's framework of expected utility serves as a model for various psychological processes, including motivation, moral sense, attitudes, and decision making. To account for evidence at variance with expected utility, we generalize the framework of fast and frugal heuristics from inferences to preferences. The priority heuristic predicts (i) Allais' paradox, (ii) risk aversion for gains if probabilities are high, (iii) risk seeking for gains if probabilities are low (lottery tickets), (iv) risk aversion for losses if probabilities are low (buying insurance), (v) risk seeking for losses if probabilities are high, (vi) certainty effect, (vii) possibility effect, and (viii) intransitivities. We test how accurately the heuristic predicts people's choices, compared to previously proposed heuristics and three modifications of expected utility theory: security-potential/aspiration theory, transfer-of-attention-exchange model, and cumulative prospect theory. PMID:16637767

  14. Theory of Randomized Search Heuristics in Combinatorial Optimization

    DEFF Research Database (Denmark)

    The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS), the Metr......The rigorous mathematical analysis of randomized search heuristics(RSHs) with respect to their expected runtime is a growing research area where many results have been obtained in recent years. This class of heuristics includes well-known approaches such as Randomized Local Search (RLS...... analysis of randomized algorithms to RSHs. Mostly, the expected runtime of RSHs on selected problems is analzyed. Thereby, we understand why and when RSHs are efficient optimizers and, conversely, when they cannot be efficient. The tutorial will give an overview on the analysis of RSHs for solving...

  15. Exploring the heuristic value of nonpersonal data for sexual- and ...

    African Journals Online (AJOL)

    Exploring the heuristic value of nonpersonal data for sexual- and ... African Safety Promotion: A Journal of Injury and Violence Prevention ... African provinces and towns were analysed to identify trends, and visually represent the number of ...

  16. Usage of Major Heuristics in Property Investment Valuation in Nigeria

    African Journals Online (AJOL)

    Toshiba

    Key words: Investment Valuation, Major Heuristics, Nigeria,. Property. ... given, estimated, or implied and then proceeds to use this information as the basis of ..... study areas take into account the effect of costly floor and wall finishes in their ...

  17. SPARSE: quadratic time simultaneous alignment and folding of RNAs without sequence-based heuristics.

    Science.gov (United States)

    Will, Sebastian; Otto, Christina; Miladi, Milad; Möhl, Mathias; Backofen, Rolf

    2015-08-01

    RNA-Seq experiments have revealed a multitude of novel ncRNAs. The gold standard for their analysis based on simultaneous alignment and folding suffers from extreme time complexity of [Formula: see text]. Subsequently, numerous faster 'Sankoff-style' approaches have been suggested. Commonly, the performance of such methods relies on sequence-based heuristics that restrict the search space to optimal or near-optimal sequence alignments; however, the accuracy of sequence-based methods breaks down for RNAs with sequence identities below 60%. Alignment approaches like LocARNA that do not require sequence-based heuristics, have been limited to high complexity ([Formula: see text] quartic time). Breaking this barrier, we introduce the novel Sankoff-style algorithm 'sparsified prediction and alignment of RNAs based on their structure ensembles (SPARSE)', which runs in quadratic time without sequence-based heuristics. To achieve this low complexity, on par with sequence alignment algorithms, SPARSE features strong sparsification based on structural properties of the RNA ensembles. Following PMcomp, SPARSE gains further speed-up from lightweight energy computation. Although all existing lightweight Sankoff-style methods restrict Sankoff's original model by disallowing loop deletions and insertions, SPARSE transfers the Sankoff algorithm to the lightweight energy model completely for the first time. Compared with LocARNA, SPARSE achieves similar alignment and better folding quality in significantly less time (speedup: 3.7). At similar run-time, it aligns low sequence identity instances substantially more accurate than RAF, which uses sequence-based heuristics. © The Author 2015. Published by Oxford University Press.

  18. SPARSE: quadratic time simultaneous alignment and folding of RNAs without sequence-based heuristics

    Science.gov (United States)

    Will, Sebastian; Otto, Christina; Miladi, Milad; Möhl, Mathias; Backofen, Rolf

    2015-01-01

    Motivation: RNA-Seq experiments have revealed a multitude of novel ncRNAs. The gold standard for their analysis based on simultaneous alignment and folding suffers from extreme time complexity of O(n6). Subsequently, numerous faster ‘Sankoff-style’ approaches have been suggested. Commonly, the performance of such methods relies on sequence-based heuristics that restrict the search space to optimal or near-optimal sequence alignments; however, the accuracy of sequence-based methods breaks down for RNAs with sequence identities below 60%. Alignment approaches like LocARNA that do not require sequence-based heuristics, have been limited to high complexity (≥ quartic time). Results: Breaking this barrier, we introduce the novel Sankoff-style algorithm ‘sparsified prediction and alignment of RNAs based on their structure ensembles (SPARSE)’, which runs in quadratic time without sequence-based heuristics. To achieve this low complexity, on par with sequence alignment algorithms, SPARSE features strong sparsification based on structural properties of the RNA ensembles. Following PMcomp, SPARSE gains further speed-up from lightweight energy computation. Although all existing lightweight Sankoff-style methods restrict Sankoff’s original model by disallowing loop deletions and insertions, SPARSE transfers the Sankoff algorithm to the lightweight energy model completely for the first time. Compared with LocARNA, SPARSE achieves similar alignment and better folding quality in significantly less time (speedup: 3.7). At similar run-time, it aligns low sequence identity instances substantially more accurate than RAF, which uses sequence-based heuristics. Availability and implementation: SPARSE is freely available at http://www.bioinf.uni-freiburg.de/Software/SPARSE. Contact: backofen@informatik.uni-freiburg.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25838465

  19. A BPMN solution for chaining OGC services to quality assure location-based crowdsourced data

    Science.gov (United States)

    Meek, Sam; Jackson, Mike; Leibovici, Didier G.

    2016-02-01

    The Open Geospatial Consortium (OGC) Web Processing Service (WPS) standard enables access to a centralized repository of processes and services from compliant clients. A crucial part of the standard includes the provision to chain disparate processes and services to form a reusable workflow. To date this has been realized by methods such as embedding XML requests, using Business Process Execution Language (BPEL) engines and other external orchestration engines. Although these allow the user to define tasks and data artifacts as web services, they are often considered inflexible and complicated, often due to vendor specific solutions and inaccessible documentation. This paper introduces a new method of flexible service chaining using the standard Business Process Markup Notation (BPMN). A prototype system has been developed upon an existing open source BPMN suite to illustrate the advantages of the approach. The motivation for the software design is qualification of crowdsourced data for use in policy-making. The software is tested as part of a project that seeks to qualify, assure, and add value to crowdsourced data in a biological monitoring use case.

  20. Development of a smart home simulator for use as a heuristic tool for management of sensor distribution.

    Science.gov (United States)

    Poland, Michael P; Nugent, Chris D; Wang, Hui; Chen, Liming

    2009-01-01

    Smart Homes offer potential solutions for various forms of independent living for the elderly. The assistive and protective environment afforded by smart homes offer a safe, relatively inexpensive, dependable and viable alternative to vulnerable inhabitants. Nevertheless, the success of a smart home rests upon the quality of information its decision support system receives and this in turn places great importance on the issue of correct sensor deployment. In this article we present a software tool that has been developed to address the elusive issue of sensor distribution within smart homes. Details of the tool will be presented and it will be shown how it can be used to emulate any real world environment whereby virtual sensor distributions can be rapidly implemented and assessed without the requirement for physical deployment for evaluation. As such, this approach offers the potential of tailoring sensor distributions to the specific needs of a patient in a non-evasive manner. The heuristics based tool presented here has been developed as the first part of a three stage project.

  1. Internal Medicine residents use heuristics to estimate disease probability

    OpenAIRE

    Phang, Sen Han; Ravani, Pietro; Schaefer, Jeffrey; Wright, Bruce; McLaughlin, Kevin

    2015-01-01

    Background: Training in Bayesian reasoning may have limited impact on accuracy of probability estimates. In this study, our goal was to explore whether residents previously exposed to Bayesian reasoning use heuristics rather than Bayesian reasoning to estimate disease probabilities. We predicted that if residents use heuristics then post-test probability estimates would be increased by non-discriminating clinical features or a high anchor for a target condition. Method: We randomized 55 In...

  2. No Need to Get Emotional? Emotions and Heuristics

    OpenAIRE

    Szigeti, Andras

    2013-01-01

    Many believe that values are crucially dependent on emotions. This paper focuses on epistemic aspects of the putative link between emotions and value by asking two related questions. First, how exactly are emotions supposed to latch onto or track values? And second, how well suited are emotions to detecting or learning about values? To answer the first question, the paper develops the heuristics-model of emotions. This approach models emotions as sui generis heuristics of value. The empirical...

  3. Neural basis of scientific innovation induced by heuristic prototype.

    Directory of Open Access Journals (Sweden)

    Junlong Luo

    Full Text Available A number of major inventions in history have been based on bionic imitation. Heuristics, by applying biological systems to the creation of artificial devices and machines, might be one of the most critical processes in scientific innovation. In particular, prototype heuristics propositions that innovation may engage automatic activation of a prototype such as a biological system to form novel associations between a prototype's function and problem-solving. We speculated that the cortical dissociation between the automatic activation and forming novel associations in innovation is critical point to heuristic creativity. In the present study, novel and old scientific innovations (NSI and OSI were selected as experimental materials in using learning-testing paradigm to explore the neural basis of scientific innovation induced by heuristic prototype. College students were required to resolve NSI problems (to which they did not know the answers and OSI problems (to which they knew the answers. From two fMRI experiments, our results showed that the subjects could resolve NSI when provided with heuristic prototypes. In Experiment 1, it was found that the lingual gyrus (LG; BA18 might be related to prototype heuristics in college students resolving NSI after learning a relative prototype. In Experiment 2, the LG (BA18 and precuneus (BA31 were significantly activated for NSI compared to OSI when college students learned all prototypes one day before the test. In addition, the mean beta-values of these brain regions of NSI were all correlated with the behavior accuracy of NSI. As our hypothesis indicated, the findings suggested that the LG might be involved in forming novel associations using heuristic information, while the precuneus might be involved in the automatic activation of heuristic prototype during scientific innovation.

  4. Neural basis of scientific innovation induced by heuristic prototype.

    Science.gov (United States)

    Luo, Junlong; Li, Wenfu; Qiu, Jiang; Wei, Dongtao; Liu, Yijun; Zhang, Qinlin

    2013-01-01

    A number of major inventions in history have been based on bionic imitation. Heuristics, by applying biological systems to the creation of artificial devices and machines, might be one of the most critical processes in scientific innovation. In particular, prototype heuristics propositions that innovation may engage automatic activation of a prototype such as a biological system to form novel associations between a prototype's function and problem-solving. We speculated that the cortical dissociation between the automatic activation and forming novel associations in innovation is critical point to heuristic creativity. In the present study, novel and old scientific innovations (NSI and OSI) were selected as experimental materials in using learning-testing paradigm to explore the neural basis of scientific innovation induced by heuristic prototype. College students were required to resolve NSI problems (to which they did not know the answers) and OSI problems (to which they knew the answers). From two fMRI experiments, our results showed that the subjects could resolve NSI when provided with heuristic prototypes. In Experiment 1, it was found that the lingual gyrus (LG; BA18) might be related to prototype heuristics in college students resolving NSI after learning a relative prototype. In Experiment 2, the LG (BA18) and precuneus (BA31) were significantly activated for NSI compared to OSI when college students learned all prototypes one day before the test. In addition, the mean beta-values of these brain regions of NSI were all correlated with the behavior accuracy of NSI. As our hypothesis indicated, the findings suggested that the LG might be involved in forming novel associations using heuristic information, while the precuneus might be involved in the automatic activation of heuristic prototype during scientific innovation.

  5. Motor heuristics and embodied choices: how to choose and act

    OpenAIRE

    Raab, M

    2017-01-01

    © 2017 Elsevier LtdHuman performance requires choosing what to do and how to do it. The goal of this theoretical contribution is to advance understanding of how the motor and cognitive components of choices are intertwined. From a holistic perspective I extend simple heuristics that have been tested in cognitive tasks to motor tasks, coining the term motor heuristics. Similarly I extend the concept of embodied cognition, that has been tested in simple sensorimotor processes changing decisions...

  6. Heuristics Miner for E-Commerce Visitor Access Pattern Representation

    OpenAIRE

    Kartina Diah Kesuma Wardhani; Wawan Yunanto

    2017-01-01

    E-commerce click stream data can form a certain pattern that describe visitor behavior while surfing the e-commerce website. This pattern can be used to initiate a design to determine alternative access sequence on the website. This research use heuristic miner algorithm to determine the pattern. σ-Algorithm and Genetic Mining are methods used for pattern recognition with frequent sequence item set approach. Heuristic Miner is an evolved form of those methods. σ-Algorithm assume that an activ...

  7. Discovery of IPV6 Router Interface Addresses via Heuristic Methods

    Science.gov (United States)

    2015-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS DISCOVERY OF IPV6 ROUTER INTERFACE ADDRESSES VIA HEURISTIC METHODS by Matthew D. Gray September...AND SUBTITLE DISCOVERY OF IPV6 ROUTER INTERFACE ADDRESSES VIA HEURISTIC METHODS 5. FUNDING NUMBERS CNS-1111445 6. AUTHOR(S) Matthew D. Gray 7...Internet Assigned Numbers Authority, there is continued pressure for widespread IPv6 adoption. Because the IPv6 address space is orders of magnitude

  8. Gene selection heuristic algorithm for nutrigenomics studies.

    Science.gov (United States)

    Valour, D; Hue, I; Grimard, B; Valour, B

    2013-07-15

    Large datasets from -omics studies need to be deeply investigated. The aim of this paper is to provide a new method (LEM method) for the search of transcriptome and metabolome connections. The heuristic algorithm here described extends the classical canonical correlation analysis (CCA) to a high number of variables (without regularization) and combines well-conditioning and fast-computing in "R." Reduced CCA models are summarized in PageRank matrices, the product of which gives a stochastic matrix that resumes the self-avoiding walk covered by the algorithm. Then, a homogeneous Markov process applied to this stochastic matrix converges the probabilities of interconnection between genes, providing a selection of disjointed subsets of genes. This is an alternative to regularized generalized CCA for the determination of blocks within the structure matrix. Each gene subset is thus linked to the whole metabolic or clinical dataset that represents the biological phenotype of interest. Moreover, this selection process reaches the aim of biologists who often need small sets of genes for further validation or extended phenotyping. The algorithm is shown to work efficiently on three published datasets, resulting in meaningfully broadened gene networks.

  9. The emotional reasoning heuristic in children.

    Science.gov (United States)

    Muris, P; Merckelbach, H; van Spauwen, I

    2003-03-01

    A previous study by Arntz, Rauner, and Van den Hout (1995; Behaviour Research and Therapy, 33, 917-925) has shown that adult anxiety patients tend to infer danger not only on the basis of objective danger information, but also on the basis of anxiety response information. The current study examined whether this so-called emotional reasoning phenomenon also occurs in children. Normal primary school children (N = 101) first completed scales tapping anxiety disorders symptoms, anxiety sensitivity, and trait anxiety. Next, they were asked to rate danger levels of scripts in which objective danger versus objective safety and anxiety response versus no anxiety response were systematically varied. Evidence was found for a general emotional reasoning effect. That is, children's danger ratings were not only a function of objective danger information, but also, in the case of objective safety scripts, by anxiety response information. This emotional reasoning effect was predicted by levels of anxiety sensitivity and trait anxiety. More specifically, high levels of anxiety sensitivity and trait anxiety were accompanied by a greater tendency to use anxiety-response information as an heuristic for assessing dangerousness of safety scripts. Implications of these findings are briefly discussed.

  10. Interliminal Design: Understanding cognitive heuristics to mitigate design distortion

    Directory of Open Access Journals (Sweden)

    Andrew McCollough

    2014-12-01

    Full Text Available Cognitive heuristics are mental shortcuts adapted over time to enable rapid interpretation of our complex environment. They are intrinsic to human cognition and resist modification. Heuristics applied outside the context to which they are best suited are termed cognitive bias, and are the cause of systematic errors in judgment and reasoning. As both a cognitive and intuitive discipline, design by individuals is vulnerable to context-inappropriate heuristic usage. Designing in groups can act positively to counterbalance these tendencies, but is subject to heuristic misuse and biases particular to social environments. Mismatch between desired and actual outcomes– termed here, design distortion – occurs when such usage goes unnoticed and unaddressed, and can affect multiple dimensions of a system. We propose a methodology, interliminal design, emerging from the Program in Collaborative Design at Pacific Northwest College of Art, to specifically address the influence of cognitive heuristics in design. This adaptive approach involves reflective, dialogic, inquiry-driven practices intended to increase awareness of heuristic usage, and identify aspects of the design process vulnerable to misuse on both individual and group levels. By facilitating the detection and mitigation of potentially costly errors in judgment and decision-making that create distortion, such metacognitive techniques can meaningfully improve design.

  11. Heuristic Optimization Approach to Selecting a Transport Connection in City Public Transport

    Directory of Open Access Journals (Sweden)

    Kul’ka Jozef

    2017-02-01

    Full Text Available The article presents a heuristic optimization approach to select a suitable transport connection in the framework of a city public transport. This methodology was applied on a part of the public transport in Košice, because it is the second largest city in the Slovak Republic and its network of the public transport creates a complex transport system, which consists of three different transport modes, namely from the bus transport, tram transport and trolley-bus transport. This solution focused on examining the individual transport services and their interconnection in relevant interchange points.

  12. Self-reconfiguration of Modular Underwater Robots using an Energy Heuristic

    DEFF Research Database (Denmark)

    Furno, Lidia; Blanke, Mogens; Galeazzi, Roberto

    2017-01-01

    This paper investigates self-reconfiguration of a modular robotic system, which consists of a cluster of modular vehicles that can attach to each other by a connection mechanism. Thereby, they can form a desired morphology to meet task specific requirements. Reconfiguration can be needed due to limi...... in morphologies. The properties of the proposed self-reconfiguration algorithm are evaluated through simulations and preliminary model tank experiments. The energy based heuristic for reconfiguration is compared to a traditional solution that minimizes the Euclidean distance....

  13. A hybrid adaptive large neighborhood search heuristic for lot-sizing with setup times

    DEFF Research Database (Denmark)

    Muller, Laurent Flindt; Spoorendonk, Simon; Pisinger, David

    2012-01-01

    This paper presents a hybrid of a general heuristic framework and a general purpose mixed-integer programming (MIP) solver. The framework is based on local search and an adaptive procedure which chooses between a set of large neighborhoods to be searched. A mixed integer programming solver and its......, and the upper bounds found by the commercial MIP solver ILOG CPLEX using state-of-the-art MIP formulations. Furthermore, we improve the best known solutions on 60 out of 100 and improve the lower bound on all 100 instances from the literature...

  14. Beyond rational expectations: the effects of heuristic switching in an overlapping generations model

    OpenAIRE

    Boone, Brecht; Quaghebeur, Ewoud

    2018-01-01

    We explore the transitional dynamics in an Overlapping Generations framework with and without heuristic switching. Agents use simple heuristics to forecast the interest rate and the real wage. The fraction of agents using a specific heuristic depends on its relative forecasting performance. In the absence of heuristic switching, the results indicate that there is a lot of variation in the transitional dynamics over different parameter values and heuristics. They might even oscillate or diverg...

  15. A heuristic for solving the redundancy allocation problem for multi-state series-parallel systems

    International Nuclear Information System (INIS)

    Ramirez-Marquez, Jose E.; Coit, David W.

    2004-01-01

    The redundancy allocation problem is formulated with the objective of minimizing design cost, when the system exhibits a multi-state reliability behavior, given system-level performance constraints. When the multi-state nature of the system is considered, traditional solution methodologies are no longer valid. This study considers a multi-state series-parallel system (MSPS) with capacitated binary components that can provide different multi-state system performance levels. The different demand levels, which must be supplied during the system-operating period, result in the multi-state nature of the system. The new solution methodology offers several distinct benefits compared to traditional formulations of the MSPS redundancy allocation problem. For some systems, recognizing that different component versions yield different system performance is critical so that the overall system reliability estimation and associated design models the true system reliability behavior more realistically. The MSPS design problem, solved in this study, has been previously analyzed using genetic algorithms (GAs) and the universal generating function. The specific problem being addressed is one where there are multiple component choices, but once a component selection is made, only the same component type can be used to provide redundancy. This is the first time that the MSPS design problem has been addressed without using GAs. The heuristic offers more efficient and straightforward analyses. Solutions to three different problem types are obtained illustrating the simplicity and ease of application of the heuristic without compromising the intended optimization needs

  16. Maximizing the nurses' preferences in nurse scheduling problem: mathematical modeling and a meta-heuristic algorithm

    Science.gov (United States)

    Jafari, Hamed; Salmasi, Nasser

    2015-09-01

    The nurse scheduling problem (NSP) has received a great amount of attention in recent years. In the NSP, the goal is to assign shifts to the nurses in order to satisfy the hospital's demand during the planning horizon by considering different objective functions. In this research, we focus on maximizing the nurses' preferences for working shifts and weekends off by considering several important factors such as hospital's policies, labor laws, governmental regulations, and the status of nurses at the end of the previous planning horizon in one of the largest hospitals in Iran i.e., Milad Hospital. Due to the shortage of available nurses, at first, the minimum total number of required nurses is determined. Then, a mathematical programming model is proposed to solve the problem optimally. Since the proposed research problem is NP-hard, a meta-heuristic algorithm based on simulated annealing (SA) is applied to heuristically solve the problem in a reasonable time. An initial feasible solution generator and several novel neighborhood structures are applied to enhance performance of the SA algorithm. Inspired from our observations in Milad hospital, random test problems are generated to evaluate the performance of the SA algorithm. The results of computational experiments indicate that the applied SA algorithm provides solutions with average percentage gap of 5.49 % compared to the upper bounds obtained from the mathematical model. Moreover, the applied SA algorithm provides significantly better solutions in a reasonable time than the schedules provided by the head nurses.

  17. A discrete firefly meta-heuristic with local search for makespan minimization in permutation flow shop scheduling problems

    Directory of Open Access Journals (Sweden)

    Nader Ghaffari-Nasab

    2010-07-01

    Full Text Available During the past two decades, there have been increasing interests on permutation flow shop with different types of objective functions such as minimizing the makespan, the weighted mean flow-time etc. The permutation flow shop is formulated as a mixed integer programming and it is classified as NP-Hard problem. Therefore, a direct solution is not available and meta-heuristic approaches need to be used to find the near-optimal solutions. In this paper, we present a new discrete firefly meta-heuristic to minimize the makespan for the permutation flow shop scheduling problem. The results of implementation of the proposed method are compared with other existing ant colony optimization technique. The preliminary results indicate that the new proposed method performs better than the ant colony for some well known benchmark problems.

  18. Heuristics in primary care for recognition of unreported vision loss in older people: a technology development study.

    Science.gov (United States)

    Wijeyekoon, Skanda; Kharicha, Kalpa; Iliffe, Steve

    2015-09-01

    To evaluate heuristics (rules of thumb) for recognition of undetected vision loss in older patients in primary care. Vision loss is associated with ageing, and its prevalence is increasing. Visual impairment has a broad impact on health, functioning and well-being. Unrecognised vision loss remains common, and screening interventions have yet to reduce its prevalence. An alternative approach is to enhance practitioners' skills in recognising undetected vision loss, by having a more detailed picture of those who are likely not to act on vision changes, report symptoms or have eye tests. This paper describes a qualitative technology development study to evaluate heuristics for recognition of undetected vision loss in older patients in primary care. Using a previous modelling study, two heuristics in the form of mnemonics were developed to aid pattern recognition and allow general practitioners to identify potential cases of unreported vision loss. These heuristics were then analysed with experts. Findings It was concluded that their implementation in modern general practice was unsuitable and an alternative solution should be sort.

  19. Deliberation in Multi-Stakeholder Participation: A Heuristic Framework Applied to the Committee on World Food Security

    Directory of Open Access Journals (Sweden)

    Matheus Alves Zanella

    2018-02-01

    Full Text Available Multi-stakeholder participation (MSP has become a central feature in several institutions and processes of global governance. Those who promote them trust that these arrangements can advance the deliberative quality of international institutions, and thereby improve the democratic quality, legitimacy and effectiveness of both the institutional landscape, as well as decisions made within it. This paper employs a heuristic framework to analyze the deliberative quality of MSP. Specifically, it applies Dryzek’s deliberative systems framework to the case of the Committee on World Food Security (CFS. The assessment shows that the CFS improves the deliberative quality of food security governance by including and facilitating the transmission of discourses from the public to the empowered spaces. However, the deliberative quality of CFS could be higher with stronger accountability mechanisms in place, more meta-deliberation and adoption of CFS outcomes at national and local levels. Reflecting on the limitations of using this heuristic framework to assess MSP, we conclude that the analysis would benefit from more explicit consideration of different forms of power that are part of the social relations between actors involved in such settings. By proposing this analytical approach, we expect to advance a heuristic framework for assessing deliberation in an international context of the growing importance of MSP in sustainability and global governance.

  20. Analytical solutions to compartmental indoor air quality models with application to environmental tobacco smoke concentrations measured in a house.

    Science.gov (United States)

    Ott, Wayne R; Klepeis, Neil E; Switzer, Paul

    2003-08-01

    This paper derives the analytical solutions to multi-compartment indoor air quality models for predicting indoor air pollutant concentrations in the home and evaluates the solutions using experimental measurements in the rooms of a single-story residence. The model uses Laplace transform methods to solve the mass balance equations for two interconnected compartments, obtaining analytical solutions that can be applied without a computer. Environmental tobacco smoke (ETS) sources such as the cigarette typically emit pollutants for relatively short times (7-11 min) and are represented mathematically by a "rectangular" source emission time function, or approximated by a short-duration source called an "impulse" time function. Other time-varying indoor sources also can be represented by Laplace transforms. The two-compartment model is more complicated than the single-compartment model and has more parameters, including the cigarette or combustion source emission rate as a function of time, room volumes, compartmental air change rates, and interzonal air flow factors expressed as dimensionless ratios. This paper provides analytical solutions for the impulse, step (Heaviside), and rectangular source emission time functions. It evaluates the indoor model in an unoccupied two-bedroom home using cigars and cigarettes as sources with continuous measurements of carbon monoxide (CO), respirable suspended particles (RSP), and particulate polycyclic aromatic hydrocarbons (PPAH). Fine particle mass concentrations (RSP or PM3.5) are measured using real-time monitors. In our experiments, simultaneous measurements of concentrations at three heights in a bedroom confirm an important assumption of the model-spatial uniformity of mixing. The parameter values of the two-compartment model were obtained using a "grid search" optimization method, and the predicted solutions agreed well with the measured concentration time series in the rooms of the home. The door and window positions in

  1. Quality of medication use in primary care - mapping the problem, working to a solution: a systematic review of the literature

    Directory of Open Access Journals (Sweden)

    Willson Alan

    2009-09-01

    Full Text Available Abstract Background The UK, USA and the World Health Organization have identified improved patient safety in healthcare as a priority. Medication error has been identified as one of the most frequent forms of medical error and is associated with significant medical harm. Errors are the result of the systems that produce them. In industrial settings, a range of systematic techniques have been designed to reduce error and waste. The first stage of these processes is to map out the whole system and its reliability at each stage. However, to date, studies of medication error and solutions have concentrated on individual parts of the whole system. In this paper we wished to conduct a systematic review of the literature, in order to map out the medication system with its associated errors and failures in quality, to assess the strength of the evidence and to use approaches from quality management to identify ways in which the system could be made safer. Methods We mapped out the medicines management system in primary care in the UK. We conducted a systematic literature review in order to refine our map of the system and to establish the quality of the research and reliability of the system. Results The map demonstrated that the proportion of errors in the management system for medicines in primary care is very high. Several stages of the process had error rates of 50% or more: repeat prescribing reviews, interface prescribing and communication and patient adherence. When including the efficacy of the medicine in the system, the available evidence suggested that only between 4% and 21% of patients achieved the optimum benefit from their medication. Whilst there were some limitations in the evidence base, including the error rate measurement and the sampling strategies employed, there was sufficient information to indicate the ways in which the system could be improved, using management approaches. The first step to improving the overall quality would

  2. On the Control of Solute Mass Fluxes and Concentrations Below Fields Irrigated With Low-Quality Water: A Numerical Study

    Science.gov (United States)

    Russo, David

    2017-11-01

    The main goal of this study was to test the capability of irrigation water-based and soil-based approaches to control nitrate and chloride mass fluxes and concentrations below the root zone of agricultural fields irrigated with treated waste water (TWW). Using numerical simulations of flow and transport in relatively a fine-textured, unsaturated, spatially heterogeneous, flow domain, scenarios examined include: (i) irrigating with TWW only (REF); (ii) irrigation water is substituted between TWW and desalinized water (ADW); (iii) soil includes a capillary barrier (CB) and irrigating with TWW only (CB + TWW); and (iv) combination of (ii) and a CB (CB + ADW). Considering groundwater quality protection, plausible goals are: (i) to minimize solute discharges leaving the root zone, and, (ii) to maximize the probability that solute concentrations leaving the root zone will not exceed a prescribed, critical value. Results of the analyses suggest that in the case of a seasonal crop (a corn field) subject to irrigations only, with respect to the first goal, the CB + TWW and CB + ADW scenarios provide similar, excellent results, better than the ADW scenario; with respect to the second goal, however, the CB + ADW scenario gave substantially better results than the CB + TWW scenario. In the case a multiyear, perennial crop (a citrus orchard), subject to a sequence of irrigation and rainfall periods, for both solutes, and, particularly, nitrate, with respect to the two goals, both the ADW and CB + ADW scenarios perform better than the CB + TWW scenario. As compared with the REF and CB + TWW scenarios, the ADW and CB + ADW scenarios substantially reduce nitrogen mass fluxes to the groundwater and to the atmosphere, and, essentially, did not reduce nitrogen mass fluxes to the trees. Similar results, even better, were demonstrated for a relatively coarse-textured, spatially heterogeneous soil.

  3. Heuristic geometric ''eigenvalue universality'' in a one-dimensional neutron transport problem with anisotropic scattering

    International Nuclear Information System (INIS)

    Goncalves, G.A.; Vilhena, M.T. de; Bodmann, B.E.J.

    2010-01-01

    In the present work we propose a heuristic construction of a transport equation for neutrons with anisotropic scattering considering only the radial cylinder dimension. The eigenvalues of the solutions of the equation correspond to the positive values for the one dimensional case. The central idea of the procedure is the application of the S N method for the discretisation of the angular variable followed by the application of the zero order Hankel transformation. The basis the construction of the scattering terms in form of an integro-differential equation for stationary transport resides in the hypothesis that the eigenvalues that compose the elementary solutions are independent of geometry for a homogeneous medium. We compare the solutions for the cartesian one dimensional problem for an infinite cylinder with azimuthal symmetry and linear anisotropic scattering for two cases. (orig.)

  4. THE IMPACT OF THE CRISIS ON THE QUALITY OF LIFE AND SOLUTIONS TO REDUCE THE CRISIS EFFECTS. CASE STUDY: ROMANIA

    Directory of Open Access Journals (Sweden)

    Fora Andreea

    2011-07-01

    Full Text Available The economic crisis creates a series of consequences such as loss of jobs, reducing wages, insecurity of the population, reducing standard of living, material hardships, low self-confidence and hope for the better, illnesses, altered human relationships, social protests, ever greater scale strikes, in other words, deterioration of the economic environment. This paper aims to identify possible solutions to improve the effects of the crisis on the quality of life, based on figures from surveys conducted by research firms and the possible correlations to be made between these dates, without attempting to consider that these solutions are unique or the best. The main indicators considered for identifying the negative aspects of the crisis among the population are: the evolution of unemployment, changes in gross domestic product or wage developments in the economy and the share of expenditure linked to the basic needs out of the income earned. Regarding the possible solutions to reduce the population crisis, they are closely related to the credit and monetary policy, and also to the budgetary policy. Under the impact of the economic crisis, the business environment in Romania has suffered. Sub impactul crizei economice, mediul de afaceri din Romania a avut de suferit. Since most investments in 2008 were of foreign origin, the fact that this crisis has affected Romania as well did not surprise anyone. Nowadays Romania's business climate is characterized by lack of direct foreign investments and self funding sources whereas the population declares itself in a large proportion -more than 50% - to be affected by the crisis (1. Effects of the crisis can also be observed in the evolution of consumers' behavior who fearing layoffs and declining revenue, not only turned to buying the same products or to purchase cheaper products, but also to reducing the amount of the purchased products. The quality of social life is essential and strongly related to

  5. Internal Medicine residents use heuristics to estimate disease probability.

    Science.gov (United States)

    Phang, Sen Han; Ravani, Pietro; Schaefer, Jeffrey; Wright, Bruce; McLaughlin, Kevin

    2015-01-01

    Training in Bayesian reasoning may have limited impact on accuracy of probability estimates. In this study, our goal was to explore whether residents previously exposed to Bayesian reasoning use heuristics rather than Bayesian reasoning to estimate disease probabilities. We predicted that if residents use heuristics then post-test probability estimates would be increased by non-discriminating clinical features or a high anchor for a target condition. We randomized 55 Internal Medicine residents to different versions of four clinical vignettes and asked them to estimate probabilities of target conditions. We manipulated the clinical data for each vignette to be consistent with either 1) using a representative heuristic, by adding non-discriminating prototypical clinical features of the target condition, or 2) using anchoring with adjustment heuristic, by providing a high or low anchor for the target condition. When presented with additional non-discriminating data the odds of diagnosing the target condition were increased (odds ratio (OR) 2.83, 95% confidence interval [1.30, 6.15], p = 0.009). Similarly, the odds of diagnosing the target condition were increased when a high anchor preceded the vignette (OR 2.04, [1.09, 3.81], p = 0.025). Our findings suggest that despite previous exposure to the use of Bayesian reasoning, residents use heuristics, such as the representative heuristic and anchoring with adjustment, to estimate probabilities. Potential reasons for attribute substitution include the relative cognitive ease of heuristics vs. Bayesian reasoning or perhaps residents in their clinical practice use gist traces rather than precise probability estimates when diagnosing.

  6. Heuristic hybrid game approach for fleet condition-based maintenance planning

    International Nuclear Information System (INIS)

    Feng, Qiang; Bi, Xiong; Zhao, Xiujie; Chen, Yiran; Sun, Bo

    2017-01-01

    The condition-based maintenance (CBM) method is commonly used to select appropriate maintenance opportunities according to equipment status over a period of time. The CBM of aircraft fleets is a fleet maintenance planning problem. In this problem, mission requirements, resource constraints, and aircraft statuses are considered to find an optimal strategy set. Given that the maintenance strategies for each aircraft are finite, fleet CBM can be treated as a combinatorial optimization problem. In this study, the process of making a decision on the CBM of military fleets is analyzed. The fleet CBM problem is treated as a two-stage dynamic decision-making problem. Aircraft are divided into dispatch and standby sets; thus, the problem scale is significantly reduced. A heuristic hybrid game (HHG) approach comprising a competition game and a cooperative game is proposed on the basis of heuristic rule. In the dispatch set, a competition game approach is proposed to search for a local optimal strategy matrix. A cooperative game method for the two sets is also proposed to ensure global optimization. Finally, a case study regarding a fleet comprising 20 aircraft is conducted, with the results proving that the approach efficiently generates outcomes that meet the mission risk-oriented schedule requirement. - Highlights: • A new heuristic hybrid game method for fleet condition-based maintenance is proposed. • The problem is simplified by hierarchical solving based on dispatch and standby set. • The local optimal solution is got by competition game algorithm for dispatch set. • The global optimal solution is got by cooperative game algorithm between two sets.

  7. A greedy heuristic using adjoint functions for the optimization of seed and needle configurations in prostate seed implant

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Sua [Department of Radiation Oncology, Duke University Medical Center, Box 3295, Durham, NC 27710 (United States); Kowalok, Michael E [Department of Radiation Oncology, Virginia Commonwealth University Health System, 401 College St., PO Box 980058, Richmond, VA 23298-0058 (United States); Thomadsen, Bruce R [Department of Medical Physics, University of Wisconsin-Madison, 1530 MSC, 1300 University Ave., Madison, WI 53706 (United States); Henderson, Douglass L [Department of Engineering Physics, University of Wisconsin-Madison, 153 Engineering Research Bldg., 1500 Engineering Dr., Madison, WI 53706 (United States)

    2007-02-07

    We continue our work on the development of an efficient treatment-planning algorithm for prostate seed implants by incorporation of an automated seed and needle configuration routine. The treatment-planning algorithm is based on region of interest (ROI) adjoint functions and a greedy heuristic. As defined in this work, the adjoint function of an ROI is the sensitivity of the average dose in the ROI to a unit-strength brachytherapy source at any seed position. The greedy heuristic uses a ratio of target and critical structure adjoint functions to rank seed positions according to their ability to irradiate the target ROI while sparing critical structure ROIs. Because seed positions are ranked in advance and because the greedy heuristic does not modify previously selected seed positions, the greedy heuristic constructs a complete seed configuration quickly. Isodose surface constraints determine the search space and the needle constraint limits the number of needles. This study additionally includes a methodology that scans possible combinations of these constraint values automatically. This automated selection scheme saves the user the effort of manually searching constraint values. With this method, clinically acceptable treatment plans are obtained in less than 2 min. For comparison, the branch-and-bound method used to solve a mixed integer-programming model took close to 2.5 h to arrive at a feasible solution. Both methods achieved good treatment plans, but the speedup provided by the greedy heuristic was a factor of approximately 100. This attribute makes this algorithm suitable for intra-operative real-time treatment planning.

  8. A greedy heuristic using adjoint functions for the optimization of seed and needle configurations in prostate seed implant

    International Nuclear Information System (INIS)

    Yoo, Sua; Kowalok, Michael E; Thomadsen, Bruce R; Henderson, Douglass L

    2007-01-01

    We continue our work on the development of an efficient treatment-planning algorithm for prostate seed implants by incorporation of an automated seed and needle configuration routine. The treatment-planning algorithm is based on region of interest (ROI) adjoint functions and a greedy heuristic. As defined in this work, the adjoint function of an ROI is the sensitivity of the average dose in the ROI to a unit-strength brachytherapy source at any seed position. The greedy heuristic uses a ratio of target and critical structure adjoint functions to rank seed positions according to their ability to irradiate the target ROI while sparing critical structure ROIs. Because seed positions are ranked in advance and because the greedy heuristic does not modify previously selected seed positions, the greedy heuristic constructs a complete seed configuration quickly. Isodose surface constraints determine the search space and the needle constraint limits the number of needles. This study additionally includes a methodology that scans possible combinations of these constraint values automatically. This automated selection scheme saves the user the effort of manually searching constraint values. With this method, clinically acceptable treatment plans are obtained in less than 2 min. For comparison, the branch-and-bound method used to solve a mixed integer-programming model took close to 2.5 h to arrive at a feasible solution. Both methods achieved good treatment plans, but the speedup provided by the greedy heuristic was a factor of approximately 100. This attribute makes this algorithm suitable for intra-operative real-time treatment planning

  9. a new meta-heuristic optimization algorithm

    Indian Academy of Sciences (India)

    N Archana

    programming obtain optimal solution to the problem by rigorous methods supplemented by gradient information. Classical methods are good for solving problems with only ... ronment for their survival and apply the concepts in finding.

  10. A meta-heuristic method for solving scheduling problem: crow search algorithm

    Science.gov (United States)

    Adhi, Antono; Santosa, Budi; Siswanto, Nurhadi

    2018-04-01

    Scheduling is one of the most important processes in an industry both in manufacturingand services. The scheduling process is the process of selecting resources to perform an operation on tasks. Resources can be machines, peoples, tasks, jobs or operations.. The selection of optimum sequence of jobs from a permutation is an essential issue in every research in scheduling problem. Optimum sequence becomes optimum solution to resolve scheduling problem. Scheduling problem becomes NP-hard problem since the number of job in the sequence is more than normal number can be processed by exact algorithm. In order to obtain optimum results, it needs a method with capability to solve complex scheduling problems in an acceptable time. Meta-heuristic is a method usually used to solve scheduling problem. The recently published method called Crow Search Algorithm (CSA) is adopted in this research to solve scheduling problem. CSA is an evolutionary meta-heuristic method which is based on the behavior in flocks of crow. The calculation result of CSA for solving scheduling problem is compared with other algorithms. From the comparison, it is found that CSA has better performance in term of optimum solution and time calculation than other algorithms.

  11. Heuristics comparison for u-shaped assembly line balancing in the apparel factory

    Directory of Open Access Journals (Sweden)

    Nuchsara Kriengkorakot

    2014-06-01

    Full Text Available In recent year, many industries have adopted a Just-in-time (JIT approach to manufacturing. One of the important changes resulting from JIT implementation is the replacement of the traditional straight lines with Ushaped assembly lines. The important characteristic of these new configurations is that multiskilled workers perform various tasks of different stations along the production line. This research is to improve the assembly line balancing in apparel factory in case study of T-shirt style 53287. The efficiency of production line was 55.48%, the factory balanced line with the traditional method in straight line. Then, the u-shaped assembly line balancing problem (UALBP is to be performed instead of straight line. By using the heuristics of Maximum Task Time, Minimum Task Time, Maximum Ranked Positional Weight (RPWmax and Greedy Randomized to determine the optimal solutions related to the number of stations and line efficiency. The results indicate that two heuristics have given the good solution which have produced by the use of Maximum Task Time and Greedy Randomized. The minimum number of stations have reduced from 17 stations to 11 stations in UALB and the line efficiency was increased from 55.48% to 85.75%. The U-line configuration frequently improves the line efficiency and has fewer work stations compared to the traditional lines.

  12. Heuristic evaluation of paper-based Web pages: a simplified inspection usability methodology.

    Science.gov (United States)

    Allen, Mureen; Currie, Leanne M; Bakken, Suzanne; Patel, Vimla L; Cimino, James J

    2006-08-01

    Online medical information, when presented to clinicians, must be well-organized and intuitive to use, so that the clinicians can conduct their daily work efficiently and without error. It is essential to actively seek to produce good user interfaces that are acceptable to the user. This paper describes the methodology used to develop a simplified heuristic evaluation (HE) suitable for the evaluation of screen shots of Web pages, the development of an HE instrument used to conduct the evaluation, and the results of the evaluation of the aforementioned screen shots. In addition, this paper presents examples of the process of categorizing problems identified by the HE and the technological solutions identified to resolve these problems. Four usability experts reviewed 18 paper-based screen shots and made a total of 108 comments. Each expert completed the task in about an hour. We were able to implement solutions to approximately 70% of the violations. Our study found that a heuristic evaluation using paper-based screen shots of a user interface was expeditious, inexpensive, and straightforward to implement.

  13. The heuristic-analytic theory of reasoning: extension and evaluation.

    Science.gov (United States)

    Evans, Jonathan St B T

    2006-06-01

    An extensively revised heuristic-analytic theory of reasoning is presented incorporating three principles of hypothetical thinking. The theory assumes that reasoning and judgment are facilitated by the formation of epistemic mental models that are generated one at a time (singularity principle) by preconscious heuristic processes that contextualize problems in such a way as to maximize relevance to current goals (relevance principle). Analytic processes evaluate these models but tend to accept them unless there is good reason to reject them (satisficing principle). At a minimum, analytic processing of models is required so as to generate inferences or judgments relevant to the task instructions, but more active intervention may result in modification or replacement of default models generated by the heuristic system. Evidence for this theory is provided by a review of a wide range of literature on thinking and reasoning.

  14. The impact of choice context on consumers' choice heuristics

    DEFF Research Database (Denmark)

    Mueller Loose, Simone; Scholderer, Joachim; Corsi, Armando M.

    2012-01-01

    Context effects in choice settings have received recent attention but little is known about the impact of context on choice consistency and the extent to which consumers apply choice heuristics. The sequence of alternatives in a choice set is examined here as one specific context effect. We compare...... how a change from a typical price order to a sensory order in wine menus affects consumer choice. We use pre-specified latent heuristic classes to analyse the existence of different choice processes, which begins to untangle the ‘black box’ of how consumers choose. Our findings indicate...... that in the absence of price order, consumers are less price-sensitive, pay more attention to visually salient cues, are less consistent in their choices and employ other simple choice heuristics more frequently than price. Implications for consumer research, marketing and consumer policy are discussed....

  15. Generalized perturbation theory (GPT) methods. A heuristic approach

    International Nuclear Information System (INIS)

    Gandini, A.

    1987-01-01

    Wigner first proposed a perturbation theory as early as 1945 to study fundamental quantities such as the reactivity worths of different materials. The first formulation, CPT, for conventional perturbation theory is based on universal quantum mechanics concepts. Since that early conception, significant contributions have been made to CPT, in particular, Soodak, who rendered a heuristic interpretation of the adjoint function, (referred to as the GPT method for generalized perturbation theory). The author illustrates the GPT methodology in a variety of linear and nonlinear domains encountered in nuclear reactor analysis. The author begins with the familiar linear neutron field and then generalizes the methodology to other linear and nonlinear fields, using heuristic arguments. The author believes that the inherent simplicity and elegance of the heuristic derivation, although intended here for reactor physics problems might be usefully adopted in collateral fields and includes such examples

  16. A Comparison of Genetic Programming Variants for Hyper-Heuristics

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Sean [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Modern society is faced with ever more complex problems, many of which can be formulated as generate-and-test optimization problems. General-purpose optimization algorithms are not well suited for real-world scenarios where many instances of the same problem class need to be repeatedly and efficiently solved, such as routing vehicles over highways with constantly changing traffic flows, because they are not targeted to a particular scenario. Hyper-heuristics automate the design of algorithms to create a custom algorithm for a particular scenario. Hyper-heuristics typically employ Genetic Programming (GP) and this project has investigated the relationship between the choice of GP and performance in Hyper-heuristics. Results are presented demonstrating the existence of problems for which there is a statistically significant performance differential between the use of different types of GP.

  17. Derivation of some formulae in combinatrics by heuristic methods

    Science.gov (United States)

    Kobayashi, Yukio

    2015-04-01

    Heuristic methods are more effective for students inlearning permutations and combinations in mathematics than passive learning such as rote memorization of formulae. Two examples, n! and 2n - 1Cn, of finding new combinatorial formulae are discussed from a pedagogical standpoint. First, the factorial of n can be expressed as ∑n - 1k = 0k . k!, which can be found by a heuristic method. This expression is comparable to representations of powers of r using geometrical series. Second, the number of possible combinations with repetition of n drawings from n elements is denoted 2n - 1Cn, which can be calculated from ∑n - 1k = 0nCk + 1n - 1Ck. The relation ∑n - 1k = 0nCk + 1n - 1Ck = 2n - 1Cn can be found by a heuristic method through a corresponding problem on mapping.

  18. Heuristic versus statistical physics approach to optimization problems

    International Nuclear Information System (INIS)

    Jedrzejek, C.; Cieplinski, L.

    1995-01-01

    Optimization is a crucial ingredient of many calculation schemes in science and engineering. In this paper we assess several classes of methods: heuristic algorithms, methods directly relying on statistical physics such as the mean-field method and simulated annealing; and Hopfield-type neural networks and genetic algorithms partly related to statistical physics. We perform the analysis for three types of problems: (1) the Travelling Salesman Problem, (2) vector quantization, and (3) traffic control problem in multistage interconnection network. In general, heuristic algorithms perform better (except for genetic algorithms) and much faster but have to be specific for every problem. The key to improving the performance could be to include heuristic features into general purpose statistical physics methods. (author)

  19. Testing a videogame intervention to recalibrate physician heuristics in trauma triage: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Mohan, Deepika; Rosengart, Matthew R; Fischhoff, Baruch; Angus, Derek C; Farris, Coreen; Yealy, Donald M; Wallace, David J; Barnato, Amber E

    2016-11-11

    , and b) cognitive load will not degrade triage performance among physicians exposed to Night Shift as much as it will among those exposed to the educational program. Serious games offer a new approach to the problem of poorly-calibrated heuristics in trauma triage. The results of this trial will contribute to the understanding of physician quality improvement and the efficacy of video games as behavioral interventions. clinicaltrials.gov; NCT02857348 ; August 2, 2016.

  20. A Comparative Survey of Adaptive Codec Solutions for VoIP over Multirate WLANs: A Capacity versus Quality Performance Trade-Off

    Directory of Open Access Journals (Sweden)

    Sfairopoulou A

    2011-01-01

    Full Text Available In multi-rate WLANs, users can suffer transmission rate changes due to the link adaptation mechanism. This results in a variable capacity channel, which is very hostile for VoIP and can cause serious quality of service (QoS degradation in all active calls. Various codec adaptation mechanisms have been proposed as a solution to this, as well as to solve congestion problems on WLAN environments. Here, these solutions are presented, categorized according to the adaptation policy and scenario they implement, and evaluated at call-level in terms of the resulting blocking and dropping probabilities, as well as the perceived voice quality. To define a common performance metric, a new index named VGoS-factor is presented, which, by combining these capacity and quality indicators, can provide an overall view of the capacity versus quality trade-off of the proposed mechanisms and consequently help in choosing the adequate policy for each scenario.

  1. Inhibitory mechanism of the matching heuristic in syllogistic reasoning.

    Science.gov (United States)

    Tse, Ping Ping; Moreno Ríos, Sergio; García-Madruga, Juan Antonio; Bajo Molina, María Teresa

    2014-11-01

    A number of heuristic-based hypotheses have been proposed to explain how people solve syllogisms with automatic processes. In particular, the matching heuristic employs the congruency of the quantifiers in a syllogism—by matching the quantifier of the conclusion with those of the two premises. When the heuristic leads to an invalid conclusion, successful solving of these conflict problems requires the inhibition of automatic heuristic processing. Accordingly, if the automatic processing were based on processing the set of quantifiers, no semantic contents would be inhibited. The mental model theory, however, suggests that people reason using mental models, which always involves semantic processing. Therefore, whatever inhibition occurs in the processing implies the inhibition of the semantic contents. We manipulated the validity of the syllogism and the congruency of the quantifier of its conclusion with those of the two premises according to the matching heuristic. A subsequent lexical decision task (LDT) with related words in the conclusion was used to test any inhibition of the semantic contents after each syllogistic evaluation trial. In the LDT, the facilitation effect of semantic priming diminished after correctly solved conflict syllogisms (match-invalid or mismatch-valid), but was intact after no-conflict syllogisms. The results suggest the involvement of an inhibitory mechanism of semantic contents in syllogistic reasoning when there is a conflict between the output of the syntactic heuristic and actual validity. Our results do not support a uniquely syntactic process of syllogistic reasoning but fit with the predictions based on mental model theory. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. After the Liverpool Care Pathway—development of heuristics to guide end of life care for people with dementia: protocol of the ALCP study

    Science.gov (United States)

    Davies, N; Manthorpe, J; Sampson, E L; Iliffe, S

    2015-01-01

    Introduction End of life care guidance for people with dementia is lacking and this has been made more problematic in England with the removal of one of the main end of life care guidelines which offered some structure, the Liverpool Care Pathway. This guidance gap may be eased with the development of heuristics (rules of thumb) which offer a fast and frugal form of decision-making. Objective To develop a toolkit of heuristics (rules of thumb) for practitioners to use when caring for people with dementia at the end of life. Method and analysis A mixed-method study using a co-design approach to develop heuristics in three phases. In phase 1, we will conduct at least six focus groups with family carers, health and social care practitioners from both hospital and community care services, using the ‘think-aloud’ method to understand decision-making processes and to develop a set of heuristics. The focus group topic guide will be developed from the findings of a previous study of 46 interviews of family carers about quality end-of-life care for people with dementia and a review of the literature. A multidisciplinary development team of health and social care practitioners will synthesise the findings from the focus groups to devise and refine a toolkit of heuristics. Phase 2 will test the use of heuristics in practice in five sites: one general practice, one community nursing team, one hospital ward and two palliative care teams working in the community. Phase 3 will evaluate and further refine the toolkit of heuristics through group interviews, online questionnaires and semistructured interviews. Ethics and dissemination This study has received ethical approval from a local NHS research ethics committee (Rec ref: 15/LO/0156). The findings of this study will be presented in peer-reviewed publications and national and international conferences. PMID:26338688

  3. After the Liverpool Care Pathway--development of heuristics to guide end of life care for people with dementia: protocol of the ALCP study.

    Science.gov (United States)

    Davies, N; Manthorpe, J; Sampson, E L; Iliffe, S

    2015-09-02

    End of life care guidance for people with dementia is lacking and this has been made more problematic in England with the removal of one of the main end of life care guidelines which offered some structure, the Liverpool Care Pathway. This guidance gap may be eased with the development of heuristics (rules of thumb) which offer a fast and frugal form of decision-making. To develop a toolkit of heuristics (rules of thumb) for practitioners to use when caring for people with dementia at the end of life. A mixed-method study using a co-design approach to develop heuristics in three phases. In phase 1, we will conduct at least six focus groups with family carers, health and social care practitioners from both hospital and community care services, using the 'think-aloud' method to understand decision-making processes and to develop a set of heuristics. The focus group topic guide will be developed from the findings of a previous study of 46 interviews of family carers about quality end-of-life care for people with dementia and a review of the literature. A multidisciplinary development team of health and social care practitioners will synthesise the findings from the focus groups to devise and refine a toolkit of heuristics. Phase 2 will test the use of heuristics in practice in five sites: one general practice, one community nursing team, one hospital ward and two palliative care teams working in the community. Phase 3 will evaluate and further refine the toolkit of heuristics through group interviews, online questionnaires and semistructured interviews. This study has received ethical approval from a local NHS research ethics committee (Rec ref: 15/LO/0156). The findings of this study will be presented in peer-reviewed publications and national and international conferences. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Improvement of the Quality and the Shelf Life of the High Oxygen Modified Atmosphere Packaged Veal by Superficial Spraying with Dihydroquercetin Solution

    Directory of Open Access Journals (Sweden)

    Stefan Georgiev Dragoev

    2014-01-01

    Full Text Available The improvement of quality and the shelf life of veal by combination of 80%O2/20%CO2 modified atmosphere packaging and superficial spraying with 0.02% dihydroquercetin solutions was studied. The control samples C, air packaged only, D, air packaged sprayed by 0.02% dihydroquercetin solution, MAP, modified atmosphere packaging only, BMAP, modified atmosphere packaging sprayed by 0.02% butylated hydroxytoluene solution, and DMAP, modified atmosphere packaging sprayed by 0.02% dihydroquercetin solution, were measured. The best results were obtained in modified atmosphere packaging sprayed by 0.02% dihydroquercetin solution. Comparisons with control samples were expressed as reduction in acid value with 27.72%, peroxide value with 64.74%, 2-thiobarbituric acid reactive substances (TBARS with 65.71%, and the pH with 6.18%. The acid and peroxide values, TBARS, and pH were decreased linearly in response when applying the combination of 80%O2/20%CO2 modified atmosphere packaging and superficial spraying with 0.02% dihydroquercetin solutions (P0.05. According to results obtained it was concluded that 80%O2/20%CO2 modified atmosphere packaged veal stored at 0±0.5°C after 0.02% dihydroquercetin solution treatment can preserve its quality and shelf life to 15 d postmortem.

  5. Reasoning by analogy as an aid to heuristic theorem proving.

    Science.gov (United States)

    Kling, R. E.

    1972-01-01

    When heuristic problem-solving programs are faced with large data bases that contain numbers of facts far in excess of those needed to solve any particular problem, their performance rapidly deteriorates. In this paper, the correspondence between a new unsolved problem and a previously solved analogous problem is computed and invoked to tailor large data bases to manageable sizes. This paper outlines the design of an algorithm for generating and exploiting analogies between theorems posed to a resolution-logic system. These algorithms are believed to be the first computationally feasible development of reasoning by analogy to be applied to heuristic theorem proving.

  6. Petri nets SM-cover-based on heuristic coloring algorithm

    Science.gov (United States)

    Tkacz, Jacek; Doligalski, Michał

    2015-09-01

    In the paper, coloring heuristic algorithm of interpreted Petri nets is presented. Coloring is used to determine the State Machines (SM) subnets. The present algorithm reduces the Petri net in order to reduce the computational complexity and finds one of its possible State Machines cover. The proposed algorithm uses elements of interpretation of Petri nets. The obtained result may not be the best, but it is sufficient for use in rapid prototyping of logic controllers. Found SM-cover will be also used in the development of algorithms for decomposition, and modular synthesis and implementation of parallel logic controllers. Correctness developed heuristic algorithm was verified using Gentzen formal reasoning system.

  7. Hyper-heuristic applied to nuclear reactor core design

    International Nuclear Information System (INIS)

    Domingos, R P; Platt, G M

    2013-01-01

    The design of nuclear reactors gives rises to a series of optimization problems because of the need for high efficiency, availability and maintenance of security levels. Gradient-based techniques and linear programming have been applied, as well as genetic algorithms and particle swarm optimization. The nonlinearity, multimodality and lack of knowledge about the problem domain makes de choice of suitable meta-heuristic models particularly challenging. In this work we solve the optimization problem of a nuclear reactor core design through the application of an optimal sequence of meta-heuritics created automatically. This combinatorial optimization model is known as hyper-heuristic.

  8. Using spatially detailed water-quality data and solute-transport modeling to improve support total maximum daily load development

    Science.gov (United States)

    Walton-Day, Katherine; Runkel, Robert L.; Kimball, Briant A.

    2012-01-01

    Spatially detailed mass-loading studies and solute-transport modeling using OTIS (One-dimensional Transport with Inflow and Storage) demonstrate how natural attenuation and loading from distinct and diffuse sources control stream water quality and affect load reductions predicted in total maximum daily loads (TMDLs). Mass-loading data collected during low-flow from Cement Creek (a low-pH, metal-rich stream because of natural and mining sources, and subject to TMDL requirements) were used to calibrate OTIS and showed spatially variable effects of natural attenuation (instream reactions) and loading from diffuse (groundwater) and distinct sources. OTIS simulations of the possible effects of TMDL-recommended remediation of mine sites showed less improvement to dissolved zinc load and concentration (14% decrease) than did the TMDL (53-63% decrease). The TMDL (1) assumed conservative transport, (2) accounted for loads removed by remediation by subtracting them from total load at the stream mouth, and (3) did not include diffuse-source loads. In OTIS, loads were reduced near their source; the resulting concentration was decreased by natural attenuation and increased by diffuse-source loads during downstream transport. Thus, by not including natural attenuation and loading from diffuse sources, the TMDL overestimated remediation effects at low flow. Use of the techniques presented herein could improve TMDLs by incorporating these processes during TMDL development.

  9. The Design of Application-Specific Heuristics for the Usability Evaluation of the Digital Doorway

    Directory of Open Access Journals (Sweden)

    Funmi Adebesin

    2012-06-01

    Full Text Available The Digital Doorway (DD is a joint initiative between the South African Department of Science and Technology (DST and the Meraka Institute of the Council for Scientific and Industrial Research (CSIR. The DD is a non-standard computer system deployed amongst underprivileged communities in South Africa with the objective to promote computer literacy. Since its inception, there has been no usability or accessibility evaluation of the software installed on the DD, mainly due to lack of usability engineering or interaction design expertise within the development team. The goal of the research presented in this paper was to design a solution to this problem by developing a suitable instrument that could guide DD application developers in the design and development of more usable DD software and interfaces. Design research was used as a research methodology. We first investigated the applicability of the standard usability and accessibility evaluation methods for evaluating the software installed on the DD. During the first cycle of design research, we established that a heuristic-like evaluation method would be an appropriate method for evaluating the usability and direct accessibility support provided by the DD. During a second cycle of design research, embedded in the first, we also developed a set of multi-category heuristics as the ‘instrument’ that could guide the developers during design of applications as well as in the first-level (formative evaluation thereof. To verify the heuristics, we conducted a usability evaluation of the DD and triangulated the results with a direct field observation at a natural environment of DD use, together with user-administered questionnaires.

  10. Multi-Criteria Optimization of the Deployment of a Grid for Rural Electrification Based on a Heuristic Method

    Science.gov (United States)

    Ortiz-Matos, L.; Aguila-Tellez, A.; Hincapié-Reyes, R. C.; González-Sanchez, J. W.

    2017-07-01

    In order to design electrification systems, recent mathematical models solve the problem of location, type of electrification components, and the design of possible distribution microgrids. However, due to the amount of points to be electrified increases, the solution to these models require high computational times, thereby becoming unviable practice models. This study posed a new heuristic method for the electrification of rural areas in order to solve the problem. This heuristic algorithm presents the deployment of rural electrification microgrids in the world, by finding routes for optimal placement lines and transformers in transmission and distribution microgrids. The challenge is to obtain a display with equity in losses, considering the capacity constraints of the devices and topology of the land at minimal economic cost. An optimal scenario ensures the electrification of all neighbourhoods to a minimum investment cost in terms of the distance between electric conductors and the amount of transformation devices.

  11. Heuristic framework for parallel sorting computations | Nwanze ...

    African Journals Online (AJOL)

    Parallel sorting techniques have become of practical interest with the advent of new multiprocessor architectures. The decreasing cost of these processors will probably in the future, make the solutions that are derived thereof to be more appealing. Efficient algorithms for sorting scheme that are encountered in a number of ...

  12. Solution Methods for the Periodic Petrol Station Replenishment Problem

    OpenAIRE

    C Triki

    2013-01-01

    In this paper we introduce the Periodic Petrol Station Replenishment Problem (PPSRP) over a T-day planning horizon and describe four heuristic methods for its solution. Even though all the proposed heuristics belong to the common partitioning-then-routing paradigm, they differ in assigning the stations to each day of the horizon. The resulting daily routing problems are then solved exactly until achieving optimalization. Moreover, an improvement procedure is also developed with the aim of ens...

  13. Heuristic approach to Satellite Range Scheduling with Bounds using Lagrangian Relaxation.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Nathanael J. K.; Arguello, Bryan; Nozick, Linda Karen; Xu, Ningxiong [Cornell

    2017-03-01

    This paper focuses on scheduling antennas to track satellites using a heuristic method. In order to validate the performance of the heuristic, bounds are developed using Lagrangian relaxation. The performance of the algorithm is established using several illustrative problems.

  14. An analysis of generalised heuristics for vehicle routing and personnel rostering problems

    OpenAIRE

    Mustafa Misir; Pieter Smet; Greet Vanden Berghe

    2015-01-01

    The present study investigates the performance of heuristics while solving problems with routing and rostering characteristics. The target problems include scheduling and routing home care, security and maintenance personnel. In analysing the behaviour of the heuristics and determining the requirements for solving the aforementioned problems, the winning hyper-heuristic from the first International Cross-domain Heuristic Search Challenge (CHeSC 2011) is employed. The completely new applicatio...

  15. MAY THE HIGH-DEGREE SATISFYING UNREASONABLE REQUIREMENT ALSO MEANS THE GOOD QUALITY: FIVE BIG FLAWS IN THE SUBJECTIVE DEFINITION OF QUALITY AND THEIR SOLUTION

    Directory of Open Access Journals (Sweden)

    Runsheng Tu

    2011-06-01

    Full Text Available J. M. Juran's subjective quality definition of "quality is degree to which a set of inherent characteristics fulfils requirements" and the account have five big inherent problems: "to disturb the language order", "to violate the objective of the standardized work", "the dependence to the subjective being too strong, to disobey the objectivity principle", "to be short of the enthusiastic limit", "to be possible to reduce the requirement through the reduction, to improve the quality", "to be possible provides the reason theoretically for the fake and shoddy manufacturer and the person whose quality is bad", "to have the suspicion of circular definition". The method to treat the wound is establishing the definition of "quality is the positive degree". This definition of quality both has guaranteed the positive connotation of J. M. Juran's quality definition and has cured the flaws of J. M. Juran's quality definition, but also has promulgated the condition of the symmetry and the connection between quality and value.

  16. Heuristically improved Bayesian segmentation of brain MR images ...

    African Journals Online (AJOL)

    Heuristically improved Bayesian segmentation of brain MR images. ... or even the most prevalent task in medical image processing is image segmentation. Among them, brain MR images suffer ... show that our algorithm performs well in comparison with the one implemented in SPM. It can be concluded that incorporating ...

  17. A genetic algorithm selection perturbative hyper-heuristic for solving ...

    African Journals Online (AJOL)

    Table 1: A summary of the characteristics of the artificial school timetabling problems. ..... One of the disadvantages of hyper-heuristics is the higher runtimes as a result .... 455–464 in AI 2002: Advances in Artificial Intelligence, Springer Berlin ...

  18. Glottochronology as a heuristic for genealogical language relationships

    NARCIS (Netherlands)

    Wichmann, S.; Holman, E.W.; Müller, A.; Velupillai, V.; List, J.-M.; Belyaev, O.; Urban, M.; Bakker, D.

    2010-01-01

    This paper applies a computerized method related to that of glottochronology and addresses the question whether such a method is useful as a heuristic for identifying deep genealogical relations among languages. We first measure lexical similarities for pairs of language families that are normally

  19. Development of Heuristic Bias Detection in Elementary School

    Science.gov (United States)

    De Neys, Wim; Feremans, Vicky

    2013-01-01

    Although human reasoning is often biased by intuitive heuristics, recent studies have shown that adults and adolescents detect the biased nature of their judgments. The present study focused on the development of this critical bias sensitivity by examining the detection skills of young children in elementary school. Third and 6th graders were…

  20. Emotions and Heuristics: The State of Perplexity in Mathematics

    Science.gov (United States)

    Gómez-Chacón, Inés M.

    2017-01-01

    Using data provided by an empirical exploratory study with mathematics undergraduates, this paper discusses some key variables in the interaction between affective and cognitive dimensions in the perplexity state in problem solving. These variables are as follows: heuristics, mathematical processes, appraisal processes [pleasantness, attentional…

  1. Heuristic Evaluation on Mobile Interfaces: A New Checklist

    Science.gov (United States)

    Yáñez Gómez, Rosa; Cascado Caballero, Daniel; Sevillano, José-Luis

    2014-01-01

    The rapid evolution and adoption of mobile devices raise new usability challenges, given their limitations (in screen size, battery life, etc.) as well as the specific requirements of this new interaction. Traditional evaluation techniques need to be adapted in order for these requirements to be met. Heuristic evaluation (HE), an Inspection Method based on evaluation conducted by experts over a real system or prototype, is based on checklists which are desktop-centred and do not adequately detect mobile-specific usability issues. In this paper, we propose a compilation of heuristic evaluation checklists taken from the existing bibliography but readapted to new mobile interfaces. Selecting and rearranging these heuristic guidelines offer a tool which works well not just for evaluation but also as a best-practices checklist. The result is a comprehensive checklist which is experimentally evaluated as a design tool. This experimental evaluation involved two software engineers without any specific knowledge about usability, a group of ten users who compared the usability of a first prototype designed without our heuristics, and a second one after applying the proposed checklist. The results of this experiment show the usefulness of the proposed checklist for avoiding usability gaps even with nontrained developers. PMID:25295300

  2. Evaluating Heuristics for Planning Effective and Efficient Inspections

    Science.gov (United States)

    Shull, Forrest J.; Seaman, Carolyn B.; Diep, Madeline M.; Feldmann, Raimund L.; Godfrey, Sara H.; Regardie, Myrna

    2010-01-01

    A significant body of knowledge concerning software inspection practice indicates that the value of inspections varies widely both within and across organizations. Inspection effectiveness and efficiency can be measured in numerous ways, and may be affected by a variety of factors such as Inspection planning, the type of software, the developing organization, and many others. In the early 1990's, NASA formulated heuristics for inspection planning based on best practices and early NASA inspection data. Over the intervening years, the body of data from NASA inspections has grown. This paper describes a multi-faceted exploratory analysis performed on this · data to elicit lessons learned in general about conducting inspections and to recommend improvements to the existing heuristics. The contributions of our results include support for modifying some of the original inspection heuristics (e.g. Increasing the recommended page rate), evidence that Inspection planners must choose between efficiency and effectiveness, as a good tradeoff between them may not exist, and Identification of small subsets of inspections for which new inspection heuristics are needed. Most Importantly, this work illustrates the value of collecting rich data on software Inspections, and using it to gain insight into, and Improve, inspection practice.

  3. Heuristic Reasoning in Chemistry: Making Decisions about Acid Strength

    Science.gov (United States)

    McClary, Lakeisha; Talanquer, Vicente

    2011-01-01

    The characterization of students' reasoning strategies is of central importance in the development of instructional strategies that foster meaningful learning. In particular, the identification of shortcut reasoning procedures (heuristics) used by students to reduce cognitive load can help us devise strategies to facilitate the development of more…

  4. Heuristics Applied in the Development of Advanced Space Mission Concepts

    Science.gov (United States)

    Nilsen, Erik N.

    1998-01-01

    Advanced mission studies are the first step in determining the feasibility of a given space exploration concept. A space scientist develops a science goal in the exploration of space. This may be a new observation method, a new instrument or a mission concept to explore a solar system body. In order to determine the feasibility of a deep space mission, a concept study is convened to determine the technology needs and estimated cost of performing that mission. Heuristics are one method of defining viable mission and systems architectures that can be assessed for technology readiness and cost. Developing a viable architecture depends to a large extent upon extending the existing body of knowledge, and applying it in new and novel ways. These heuristics have evolved over time to include methods for estimating technical complexity, technology development, cost modeling and mission risk in the unique context of deep space missions. This paper examines the processes involved in performing these advanced concepts studies, and analyzes the application of heuristics in the development of an advanced in-situ planetary mission. The Venus Surface Sample Return mission study provides a context for the examination of the heuristics applied in the development of the mission and systems architecture. This study is illustrative of the effort involved in the initial assessment of an advance mission concept, and the knowledge and tools that are applied.

  5. Cultural heuristics in risk assessment of HIV/AIDS

    NARCIS (Netherlands)

    Bailey, A.; Hutter, I.

    2006-01-01

    Behaviour change models in HIV prevention tend to consider that risky sexual behaviours reflect risk assessments and that by changing risk assessments behaviour can be changed. Risk assessment is however culturally constructed. Individuals use heuristics or bounded cognitive devices derived from

  6. Applied Decision Making With Fast-and-Frugal Heuristics

    NARCIS (Netherlands)

    Hafenbrädl, S.; Waeger, D.; Marewski, J.N.; Gigerenzer, G.

    In applied settings, such as aviation, medicine, and finance, individuals make decisions under various degrees of uncertainty, that is, when not all risks are known or can be calculated. In such situations, decisions can be made using fast-and-frugal heuristics. These are simple strategies that

  7. Concentrated Hitting Times of Randomized Search Heuristics with Variable Drift

    DEFF Research Database (Denmark)

    Lehre, Per Kristian; Witt, Carsten

    2014-01-01

    Drift analysis is one of the state-of-the-art techniques for the runtime analysis of randomized search heuristics (RSHs) such as evolutionary algorithms (EAs), simulated annealing etc. The vast majority of existing drift theorems yield bounds on the expected value of the hitting time for a target...

  8. Heuristics for Relevancy Ranking of Earth Dataset Search Results

    Science.gov (United States)

    Lynnes, Christopher; Quinn, Patrick; Norton, James

    2016-01-01

    As the Variety of Earth science datasets increases, science researchers find it more challenging to discover and select the datasets that best fit their needs. The most common way of search providers to address this problem is to rank the datasets returned for a query by their likely relevance to the user. Large web page search engines typically use text matching supplemented with reverse link counts, semantic annotations and user intent modeling. However, this produces uneven results when applied to dataset metadata records simply externalized as a web page. Fortunately, data and search provides have decades of experience in serving data user communities, allowing them to form heuristics that leverage the structure in the metadata together with knowledge about the user community. Some of these heuristics include specific ways of matching the user input to the essential measurements in the dataset and determining overlaps of time range and spatial areas. Heuristics based on the novelty of the datasets can prioritize later, better versions of data over similar predecessors. And knowledge of how different user types and communities use data can be brought to bear in cases where characteristics of the user (discipline, expertise) or their intent (applications, research) can be divined. The Earth Observing System Data and Information System has begun implementing some of these heuristics in the relevancy algorithm of its Common Metadata Repository search engine.

  9. Heuristics and NCLB Standardized Tests: A Convenient Lie

    Science.gov (United States)

    Dodge, Arnold

    2009-01-01

    The No Child Left Behind Act of 2001 requires public schools in the United States to test students in grades 3-8. The author argues that this mandate has been supported by the public, in part, because of the "availability heuristic," a phenomenon which occurs when people assess the probability of an event by the ease with which instances…

  10. Sensitivity analysis of a greedy heuristic for knapsack problems

    NARCIS (Netherlands)

    Ghosh, D; Chakravarti, N; Sierksma, G

    2006-01-01

    In this paper, we carry out parametric analysis as well as a tolerance limit based sensitivity analysis of a greedy heuristic for two knapsack problems-the 0-1 knapsack problem and the subset sum problem. We carry out the parametric analysis based on all problem parameters. In the tolerance limit

  11. Heuristic Evaluation on Mobile Interfaces: A New Checklist

    Directory of Open Access Journals (Sweden)

    Rosa Yáñez Gómez

    2014-01-01

    Full Text Available The rapid evolution and adoption of mobile devices raise new usability challenges, given their limitations (in screen size, battery life, etc. as well as the specific requirements of this new interaction. Traditional evaluation techniques need to be adapted in order for these requirements to be met. Heuristic evaluation (HE, an Inspection Method based on evaluation conducted by experts over a real system or prototype, is based on checklists which are desktop-centred and do not adequately detect mobile-specific usability issues. In this paper, we propose a compilation of heuristic evaluation checklists taken from the existing bibliography but readapted to new mobile interfaces. Selecting and rearranging these heuristic guidelines offer a tool which works well not just for evaluation but also as a best-practices checklist. The result is a comprehensive checklist which is experimentally evaluated as a design tool. This experimental evaluation involved two software engineers without any specific knowledge about usability, a group of ten users who compared the usability of a first prototype designed without our heuristics, and a second one after applying the proposed checklist. The results of this experiment show the usefulness of the proposed checklist for avoiding usability gaps even with nontrained developers.

  12. A rescheduling heuristic for the single machine total tardiness problem

    African Journals Online (AJOL)

    In this paper, we propose a rescheduling heuristic for scheduling N jobs on a .... the schedules which start both jobs i and j after time T, there is an optimal ..... [14] Picard J & Queyranne M, 1978, The time-dependent traveling salesman problem.

  13. Insights in cognitive patterns : Essays on heuristics and identification

    NARCIS (Netherlands)

    Rothengatter, Marloes

    2016-01-01

    People are inclined to find patterns in everything they sense, even if there is no pattern to discover. Humans use action-oriented mental patterns as rules of thumb, so called heuristics, in speedy decision-making. At the same time, we see this desire for pattern finding in social orderliness, in

  14. Divergence of Scientific Heuristic Method and Direct Algebraic Instruction

    Science.gov (United States)

    Calucag, Lina S.

    2016-01-01

    This is an experimental study, made used of the non-randomized experimental and control groups, pretest-posttest designs. The experimental and control groups were two separate intact classes in Algebra. For a period of twelve sessions, the experimental group was subjected to the scientific heuristic method, but the control group instead was given…

  15. Making Predictions about Chemical Reactivity: Assumptions and Heuristics

    Science.gov (United States)

    Maeyer, Jenine; Talanquer, Vicente

    2013-01-01

    Diverse implicit cognitive elements seem to support but also constrain reasoning in different domains. Many of these cognitive constraints can be thought of as either implicit assumptions about the nature of things or reasoning heuristics for decision-making. In this study we applied this framework to investigate college students' understanding of…

  16. The Dialectical Utility of Heuristic Processing in Outdoor Adventure Education

    Science.gov (United States)

    Zajchowski, Chris A. B.; Brownlee, Matthew T. J.; Furman, Nate N.

    2016-01-01

    Heuristics--cognitive shortcuts used in decision-making events--have been paradoxically praised for their contribution to decision-making efficiency and prosecuted for their contribution to decision-making error (Gigerenzer & Gaissmaier, 2011; Gigerenzer, Todd, & ABC Research Group, 1999; Kahneman, 2011; Kahneman, Slovic, & Tversky,…

  17. Heuristic burst detection method using flow and pressure measurements

    NARCIS (Netherlands)

    Bakker, M.; Vreeburg, J.H.G.; Roer, Van de M.; Rietveld, L.C.

    2014-01-01

    Pipe bursts in a drinking water distribution system lead to water losses, interruption of supply, and damage to streets and houses due to the uncontrolled water flow. To minimize the negative consequences of pipe bursts, an early detection is necessary. This paper describes a heuristic burst

  18. How cognitive heuristics can explain social interactions in spatial movement.

    Science.gov (United States)

    Seitz, Michael J; Bode, Nikolai W F; Köster, Gerta

    2016-08-01

    The movement of pedestrian crowds is a paradigmatic example of collective motion. The precise nature of individual-level behaviours underlying crowd movements has been subject to a lively debate. Here, we propose that pedestrians follow simple heuristics rooted in cognitive psychology, such as 'stop if another step would lead to a collision' or 'follow the person in front'. In other words, our paradigm explicitly models individual-level behaviour as a series of discrete decisions. We show that our cognitive heuristics produce realistic emergent crowd phenomena, such as lane formation and queuing behaviour. Based on our results, we suggest that pedestrians follow different cognitive heuristics that are selected depending on the context. This differs from the widely used approach of capturing changes in behaviour via model parameters and leads to testable hypotheses on changes in crowd behaviour for different motivation levels. For example, we expect that rushed individuals more often evade to the side and thus display distinct emergent queue formations in front of a bottleneck. Our heuristics can be ranked according to the cognitive effort that is required to follow them. Therefore, our model establishes a direct link between behavioural responses and cognitive effort and thus facilitates a novel perspective on collective behaviour. © 2016 The Author(s).

  19. The afforestation problem: a heuristic method based on simulated annealing

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui

    1992-01-01

    This paper presents the afforestation problem, that is the location and design of new forest compartments to be planted in a given area. This optimization problem is solved by a two-step heuristic method based on simulated annealing. Tests and experiences with this method are also presented....

  20. Heuristic Scheduling Algorithm Oriented Dynamic Tasks for Imaging Satellites

    Directory of Open Access Journals (Sweden)

    Maocai Wang

    2014-01-01

    Full Text Available Imaging satellite scheduling is an NP-hard problem with many complex constraints. This paper researches the scheduling problem for dynamic tasks oriented to some emergency cases. After the dynamic properties of satellite scheduling were analyzed, the optimization model is proposed in this paper. Based on the model, two heuristic algorithms are proposed to solve the problem. The first heuristic algorithm arranges new tasks by inserting or deleting them, then inserting them repeatedly according to the priority from low to high, which is named IDI algorithm. The second one called ISDR adopts four steps: insert directly, insert by shifting, insert by deleting, and reinsert the tasks deleted. Moreover, two heuristic factors, congestion degree of a time window and the overlapping degree of a task, are employed to improve the algorithm’s performance. Finally, a case is given to test the algorithms. The results show that the IDI algorithm is better than ISDR from the running time point of view while ISDR algorithm with heuristic factors is more effective with regard to algorithm performance. Moreover, the results also show that our method has good performance for the larger size of the dynamic tasks in comparison with the other two methods.