Absolute Points for Multiple Assignment Problems
ERIC Educational Resources Information Center
Adlakha, V.; Kowalski, K.
2006-01-01
An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group absolute points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…
Waples, Robin S
2010-07-01
Recognition of the importance of cross-validation ('any technique or instance of assessing how the results of a statistical analysis will generalize to an independent dataset'; Wiktionary, en.wiktionary.org) is one reason that the U.S. Securities and Exchange Commission requires all investment products to carry some variation of the disclaimer, 'Past performance is no guarantee of future results.' Even a cursory examination of financial behaviour, however, demonstrates that this warning is regularly ignored, even by those who understand what an independent dataset is. In the natural sciences, an analogue to predicting future returns for an investment strategy is predicting power of a particular algorithm to perform with new data. Once again, the key to developing an unbiased assessment of future performance is through testing with independent data--that is, data that were in no way involved in developing the method in the first place. A 'gold-standard' approach to cross-validation is to divide the data into two parts, one used to develop the algorithm, the other used to test its performance. Because this approach substantially reduces the sample size that can be used in constructing the algorithm, researchers often try other variations of cross-validation to accomplish the same ends. As illustrated by Anderson in this issue of Molecular Ecology Resources, however, not all attempts at cross-validation produce the desired result. Anderson used simulated data to evaluate performance of several software programs designed to identify subsets of loci that can be effective for assigning individuals to population of origin based on multilocus genetic data. Such programs are likely to become increasingly popular as researchers seek ways to streamline routine analyses by focusing on small sets of loci that contain most of the desired signal. Anderson found that although some of the programs made an attempt at cross-validation, all failed to meet the 'gold standard' of using
The Airport Gate Assignment Problem: A Survey
Ghaleb, Mageed A.; Salem, Ahmed M.
2014-01-01
The airport gate assignment problem (AGAP) is one of the most important problems operations managers face daily. Many researches have been done to solve this problem and tackle its complexity. The objective of the task is assigning each flight (aircraft) to an available gate while maximizing both conveniences to passengers and the operational efficiency of airport. This objective requires a solution that provides the ability to change and update the gate assignment data on a real time basis. In this paper, we survey the state of the art of these problems and the various methods to obtain the solution. Our survey covers both theoretical and real AGAP with the description of mathematical formulations and resolution methods such as exact algorithms, heuristic algorithms, and metaheuristic algorithms. We also provide a research trend that can inspire researchers about new problems in this area. PMID:25506074
The airport gate assignment problem: a survey.
Bouras, Abdelghani; Ghaleb, Mageed A; Suryahatmaja, Umar S; Salem, Ahmed M
2014-01-01
The airport gate assignment problem (AGAP) is one of the most important problems operations managers face daily. Many researches have been done to solve this problem and tackle its complexity. The objective of the task is assigning each flight (aircraft) to an available gate while maximizing both conveniences to passengers and the operational efficiency of airport. This objective requires a solution that provides the ability to change and update the gate assignment data on a real time basis. In this paper, we survey the state of the art of these problems and the various methods to obtain the solution. Our survey covers both theoretical and real AGAP with the description of mathematical formulations and resolution methods such as exact algorithms, heuristic algorithms, and metaheuristic algorithms. We also provide a research trend that can inspire researchers about new problems in this area. PMID:25506074
Unifying Temporal and Structural Credit Assignment Problems
NASA Technical Reports Server (NTRS)
Agogino, Adrian K.; Tumer, Kagan
2004-01-01
Single-agent reinforcement learners in time-extended domains and multi-agent systems share a common dilemma known as the credit assignment problem. Multi-agent systems have the structural credit assignment problem of determining the contributions of a particular agent to a common task. Instead, time-extended single-agent systems have the temporal credit assignment problem of determining the contribution of a particular action to the quality of the full sequence of actions. Traditionally these two problems are considered different and are handled in separate ways. In this article we show how these two forms of the credit assignment problem are equivalent. In this unified frame-work, a single-agent Markov decision process can be broken down into a single-time-step multi-agent process. Furthermore we show that Monte-Carlo estimation or Q-learning (depending on whether the values of resulting actions in the episode are known at the time of learning) are equivalent to different agent utility functions in a multi-agent system. This equivalence shows how an often neglected issue in multi-agent systems is equivalent to a well-known deficiency in multi-time-step learning and lays the basis for solving time-extended multi-agent problems, where both credit assignment problems are present.
A multistage linear array assignment problem
NASA Technical Reports Server (NTRS)
Nicol, David M.; Shier, D. R.; Kincaid, R. K.; Richards, D. S.
1988-01-01
The implementation of certain algorithms on parallel processing computing architectures can involve partitioning contiguous elements into a fixed number of groups, each of which is to be handled by a single processor. It is desired to find an assignment of elements to processors that minimizes the sum of the maximum workloads experienced at each stage. This problem can be viewed as a multi-objective network optimization problem. Polynomially-bounded algorithms are developed for the case of two stages, whereas the associated decision problem (for an arbitrary number of stages) is shown to be NP-complete. Heuristic procedures are therefore proposed and analyzed for the general problem. Computational experience with one of the exact problems, incorporating certain pruning rules, is presented with one of the exact problems. Empirical results also demonstrate that one of the heuristic procedures is especially effective in practice.
Solving multiconstraint assignment problems using learning automata.
Horn, Geir; Oommen, B John
2010-02-01
This paper considers the NP-hard problem of object assignment with respect to multiple constraints: assigning a set of elements (or objects) into mutually exclusive classes (or groups), where the elements which are "similar" to each other are hopefully located in the same class. The literature reports solutions in which the similarity constraint consists of a single index that is inappropriate for the type of multiconstraint problems considered here and where the constraints could simultaneously be contradictory. This feature, where we permit possibly contradictory constraints, distinguishes this paper from the state of the art. Indeed, we are aware of no learning automata (or other heuristic) solutions which solve this problem in its most general setting. Such a scenario is illustrated with the static mapping problem, which consists of distributing the processes of a parallel application onto a set of computing nodes. This is a classical and yet very important problem within the areas of parallel computing, grid computing, and cloud computing. We have developed four learning-automata (LA)-based algorithms to solve this problem: First, a fixed-structure stochastic automata algorithm is presented, where the processes try to form pairs to go onto the same node. This algorithm solves the problem, although it requires some centralized coordination. As it is desirable to avoid centralized control, we subsequently present three different variable-structure stochastic automata (VSSA) algorithms, which have superior partitioning properties in certain settings, although they forfeit some of the scalability features of the fixed-structure algorithm. All three VSSA algorithms model the processes as automata having first the hosting nodes as possible actions; second, the processes as possible actions; and, third, attempting to estimate the process communication digraph prior to probabilistically mapping the processes. This paper, which, we believe, comprehensively reports the
Approximate algorithms for partitioning and assignment problems
NASA Technical Reports Server (NTRS)
Iqbal, M. A.
1986-01-01
The problem of optimally assigning the modules of a parallel/pipelined program over the processors of a multiple computer system under certain restrictions on the interconnection structure of the program as well as the multiple computer system was considered. For a variety of such programs it is possible to find linear time if a partition of the program exists in which the load on any processor is within a certain bound. This method, when combined with a binary search over a finite range, provides an approximate solution to the partitioning problem. The specific problems considered were: a chain structured parallel program over a chain-like computer system, multiple chain-like programs over a host-satellite system, and a tree structured parallel program over a host-satellite system. For a problem with m modules and n processors, the complexity of the algorithm is no worse than O(mnlog(W sub T/epsilon)), where W sub T is the cost of assigning all modules to one processor and epsilon the desired accuracy.
49 CFR 821.35 - Assignment, duties and powers.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 49 Transportation 7 2011-10-01 2011-10-01 false Assignment, duties and powers. 821.35 Section 821... powers. (a) Assignment of law judge and duration of assignment. The chief law judge shall assign a law...) Powers of law judge. Law judges shall have the following powers: (1) To give notice of, and to...
49 CFR 821.35 - Assignment, duties and powers.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 7 2013-10-01 2013-10-01 false Assignment, duties and powers. 821.35 Section 821... powers. (a) Assignment of law judge and duration of assignment. The chief law judge shall assign a law...) Powers of law judge. Law judges shall have the following powers: (1) To give notice of, and to...
Phase transition in the assignment problem for random matrices
NASA Astrophysics Data System (ADS)
Esteve, J. G.; Falceto, F.
2005-12-01
We report an analytic and numerical study of a phase transition in a P problem (the assignment problem) that separates two phases whose representatives are the simple matching problem (an easy P problem) and the traveling-salesman problem (a NP-complete problem). Like other phase transitions found in combinatoric problems (K-satisfiability, number partitioning) this can help to understand the nature of the difficulties in solving NP problems an to find more accurate algorithms for them.
49 CFR 821.35 - Assignment, duties and powers.
Code of Federal Regulations, 2010 CFR
2010-10-01
... SAFETY BOARD RULES OF PRACTICE IN AIR SAFETY PROCEEDINGS Law Judges § 821.35 Assignment, duties and powers. (a) Assignment of law judge and duration of assignment. The chief law judge shall assign a law... addressed to the Case Manager for handling by the chief law judge, who may handle these matters...
NASA Astrophysics Data System (ADS)
Shibata, Kazuaki; Horio, Yoshihiko; Aihara, Kazuyuki
The quadratic assignment problem (QAP) is one of the NP-hard combinatorial optimization problems. An exponential chaotic tabu search using a 2-opt algorithm driven by chaotic neuro-dynamics has been proposed as one heuristic method for solving QAPs. In this paper we first propose a new local search, the double-assignment method, suitable for the exponential chaotic tabu search, which adopts features of the Lin-Kernighan algorithm. We then introduce chaotic neuro-dynamics into the double-assignment method to propose a novel exponential chaotic tabu search. We further improve the proposed exponential chaotic tabu search with the double-assignment method by enhancing the effect of chaotic neuro-dynamics.
The generalized pole assignment problem. [dynamic output feedback problems
NASA Technical Reports Server (NTRS)
Djaferis, T. E.; Mitter, S. K.
1979-01-01
Two dynamic output feedback problems for a linear, strictly proper system are considered, along with their interrelationships. The problems are formulated in the frequency domain and investigated in terms of linear equations over rings of polynomials. Necessary and sufficient conditions are expressed using genericity.
Complexity and Approximation of a Geometric Local Robot Assignment Problem
NASA Astrophysics Data System (ADS)
Bonorden, Olaf; Degener, Bastian; Kempkes, Barbara; Pietrzyk, Peter
We introduce a geometric multi-robot assignment problem. Robots positioned in a Euclidean space have to be assigned to treasures in such a way that their joint strength is sufficient to unearth a treasure with a given weight. The robots have a limited range and thus can only be assigned to treasures in their proximity. The objective is to unearth as many treasures as possible. We investigate the complexity of several variants of this problem and show whether they are in {mathcal P} or are mathcal{ NP}-complete. Furthermore, we provide a distributed and local constant-factor approximation algorithm using constant-factor resource augmentation for the two-dimensional setting with {mathcal O}(log^*n) communication rounds.
An Improved Approach to Solution of the Faculty Assignment Problem.
ERIC Educational Resources Information Center
Yang, Chin W.
1989-01-01
Examined is the problem of assigning faculty members to teach various courses in an accounting department. Based on selected evaluation information, a zero-one integer programing model was implemented. This approach utilizes readily available data and takes into consideration the learning curve phenomenon, various competing needs, and…
Web-Based Problem-Solving Assignment and Grading System
NASA Astrophysics Data System (ADS)
Brereton, Giles; Rosenberg, Ronald
2014-11-01
In engineering courses with very specific learning objectives, such as fluid mechanics and thermodynamics, it is conventional to reinforce concepts and principles with problem-solving assignments and to measure success in problem solving as an indicator of student achievement. While the modern-day ease of copying and searching for online solutions can undermine the value of traditional assignments, web-based technologies also provide opportunities to generate individualized well-posed problems with an infinite number of different combinations of initial/final/boundary conditions, so that the probability of any two students being assigned identical problems in a course is vanishingly small. Such problems can be designed and programmed to be: single or multiple-step, self-grading, allow students single or multiple attempts; provide feedback when incorrect; selectable according to difficulty; incorporated within gaming packages; etc. In this talk, we discuss the use of a homework/exam generating program of this kind in a single-semester course, within a web-based client-server system that ensures secure operation.
A polyhedral approach to a constrained assignment problem
Hefner, A.; Kleinschmidt, P.
1994-12-31
We consider the following problem (called the Master/Slave-Matching Problem): Given an undirected bipartite graph G(V, E) with bipartition V = W {union} U and a digraph D = (U, A). A Master/Slave-matching in G is a matching in G such that for every arc (u, v) {element_of} A the node v is matched whenever the node u is matched. The problem is, to find a Master/Slave-matching of maximum cardinality. The motivation for the study of this problem arises from the area of manpower scheduling where one tries to assign workers to jobs such that the assigned jobs satisfy certain dependence constraints. Let k be the maximum size of a (weakly) connected component of D. First we show that the problem is NP-hard and remains NP-hard even if k = 3. Second we focus on the case k = 2: We use polyhedral combinatorics to establish a min-max equation which well-characterizes the cardinality of a maximum Master/Slave-matching. This equation can be viewed as a generalization of Konig`s min-max theorem. Finally, we show (for k = 2) how the weighted Master/Slave-Matching Problem (where every edge e {element_of} E has a nonnegative weight) can be transformed to the (non-bipartite) weighted Matching Problem.
Principles for problem aggregation and assignment in medium scale multiprocessors
NASA Technical Reports Server (NTRS)
Nicol, David M.; Saltz, Joel H.
1987-01-01
One of the most important issues in parallel processing is the mapping of workload to processors. This paper considers a large class of problems having a high degree of potential fine grained parallelism, and execution requirements that are either not predictable, or are too costly to predict. The main issues in mapping such a problem onto medium scale multiprocessors are those of aggregation and assignment. We study a method of parameterized aggregation that makes few assumptions about the workload. The mapping of aggregate units of work onto processors is uniform, and exploits locality of workload intensity to balance the unknown workload. In general, a finer aggregate granularity leads to a better balance at the price of increased communication/synchronization costs; the aggregation parameters can be adjusted to find a reasonable granularity. The effectiveness of this scheme is demonstrated on three model problems: an adaptive one-dimensional fluid dynamics problem with message passing, a sparse triangular linear system solver on both a shared memory and a message-passing machine, and a two-dimensional time-driven battlefield simulation employing message passing. Using the model problems, the tradeoffs are studied between balanced workload and the communication/synchronization costs. Finally, an analytical model is used to explain why the method balances workload and minimizes the variance in system behavior.
Solution of the determinantal assignment problem using the Grassmann matrices
NASA Astrophysics Data System (ADS)
Karcanias, Nicos; Leventides, John
2016-02-01
The paper provides a direct solution to the determinantal assignment problem (DAP) which unifies all frequency assignment problems of the linear control theory. The current approach is based on the solvability of the exterior equation ? where ? is an n -dimensional vector space over ? which is an integral part of the solution of DAP. New criteria for existence of solution and their computation based on the properties of structured matrices are referred to as Grassmann matrices. The solvability of this exterior equation is referred to as decomposability of ?, and it is in turn characterised by the set of quadratic Plücker relations (QPRs) describing the Grassmann variety of the corresponding projective space. Alternative new tests for decomposability of the multi-vector ? are given in terms of the rank properties of the Grassmann matrix, ? of the vector ?, which is constructed by the coordinates of ?. It is shown that the exterior equation is solvable (? is decomposable), if and only if ? where ?; the solution space for a decomposable ?, is the space ?. This provides an alternative linear algebra characterisation of the decomposability problem and of the Grassmann variety to that defined by the QPRs. Further properties of the Grassmann matrices are explored by defining the Hodge-Grassmann matrix as the dual of the Grassmann matrix. The connections of the Hodge-Grassmann matrix to the solution of exterior equations are examined, and an alternative new characterisation of decomposability is given in terms of the dimension of its image space. The framework based on the Grassmann matrices provides the means for the development of a new computational method for the solutions of the exact DAP (when such solutions exist), as well as computing approximate solutions, when exact solutions do not exist.
Neural-network dedicated processor for solving competitive assignment problems
NASA Technical Reports Server (NTRS)
Eberhardt, Silvio P. (Inventor)
1993-01-01
A neural-network processor for solving first-order competitive assignment problems consists of a matrix of N x M processing units, each of which corresponds to the pairing of a first number of elements of (R sub i) with a second number of elements (C sub j), wherein limits of the first number are programmed in row control superneurons, and limits of the second number are programmed in column superneurons as MIN and MAX values. The cost (weight) W sub ij of the pairings is programmed separately into each PU. For each row and column of PU's, a dedicated constraint superneuron insures that the number of active neurons within the associated row or column fall within a specified range. Annealing is provided by gradually increasing the PU gain for each row and column or increasing positive feedback to each PU, the latter being effective to increase hysteresis of each PU or by combining both of these techniques.
Planning Nurses in Maternity Care: a Stochastic Assignment Problem
NASA Astrophysics Data System (ADS)
Phillipson, Frank
2015-05-01
With 23 percent of all births taking place at home, The Netherlands have the highest rate of home births in the world. Also if the birth did not take place at home, it is not unusual for the mother and child to be out of hospital in a few hours after the baby was born. The explanation for both is the very well organised maternity care system. However, getting the right maternity care nurse available on time introduces a complex planning issue that can be recognized as a Stochastic Assignment Problem. In this paper an expert rule based approach is combined with scenario analysis to support the planner of the maternity care agency in his work.
Space Power Engineering Problems
NASA Astrophysics Data System (ADS)
Senkevich, V. P.
2002-01-01
Development of space power engineering in the first half of XXI century shall be aimed at preventing the forthcoming energy crisis and ecological catastrophes. The problem can be solved through using solar energy being perpetual, endless, and ecologically safe. As of now, issues on the development and employment of solar power stations and its beaming to the ground stations in the SHF band are put on the agenda. The most pressing problem is to develop orbital solar reflectors to illuminate towns in the polar regions, agricultural regions, and areas of processing sea products. Space-based technologies can be used to deal with typhoons, green house effects, and "ozone holes". Recently, large, frameless film structures formed by centrifugal forces offer the promise of structures for orbital power plants, reflectors, and solar sails. A big success is achieved in the development of power generating solar array elements of amorphous silicon. These innovations would make the development of orbital solar power plants dozens of times cheaper. Such solar arrays shall be used in the nearest future on heavy communication satellites and the Earth remote sensing platforms for generation of 140-160 kW at a specific power beyond 300 W/kg. The cargo traffic needed to develop and maintain the orbital power plants and reflector systems could be equipped with solar sails as the future low thrust propulsion. In 2000, the mankind witnessed an unexpected beginning of energy crisis along with strong hydro- meteorological events (typhoons, floods) that shocked the USA, the Western Europe, England, Japan, and other countries. The total damage is estimated as 90 billions of dollars. The mankind is approaching a boundary beyond which its further existence would depend on how people would learn to control weather and use ecologically safe power sources. Space technology base on the research potential accumulated in the previous century could serve for the solution of this problem.
Massively parallel solution of the assignment problem. Technical report
Wein, J.; Zenios, S.
1990-12-01
In this paper we discuss the design, implementation and effectiveness of massively parallel algorithms for the solution of large-scale assignment problems. In particular, we study the auction algorithms of Bertsekas, an algorithm based on the method of multipliers of Hestenes and Powell, and an algorithm based on the alternating direction method of multipliers of Eckstein. We discuss alternative approaches to the massively parallel implementation of the auction algorithm, including Jacobi, Gauss-Seidel and a hybrid scheme. The hybrid scheme, in particular, exploits two different levels of parallelism and an efficient way of communicating the data between them without the need to perform general router operations across the hypercube network. We then study the performance of massively parallel implementations of two methods of multipliers. Implementations are carried out on the Connection Machine CM-2, and the algorithms are evaluated empirically with the solution of large scale problems. The hybrid scheme significantly outperforms all of the other methods and gives the best computational results to date for a massively parallel solution to this problem.
Method for assigning sites to projected generic nuclear power plants
Holter, G.M.; Purcell, W.L.; Shutz, M.E.; Young, J.R.
1986-07-01
Pacific Northwest Laboratory developed a method for forecasting potential locations and startup sequences of nuclear power plants that will be required in the future but have not yet been specifically identified by electric utilities. Use of the method results in numerical ratings for potential nuclear power plant sites located in each of the 10 federal energy regions. The rating for each potential site is obtained from numerical factors assigned to each of 5 primary siting characteristics: (1) cooling water availability, (2) site land area, (3) power transmission land area, (4) proximity to metropolitan areas, and (5) utility plans for the site. The sequence of plant startups in each federal energy region is obtained by use of the numerical ratings and the forecasts of generic nuclear power plant startups obtained from the EIA Middle Case electricity forecast. Sites are assigned to generic plants in chronological order according to startup date.
Cerebellar Synaptic Plasticity and the Credit Assignment Problem.
Jörntell, Henrik
2016-04-01
The mechanism by which a learnt synaptic weight change can contribute to learning or adaptation of brain function is a type of credit assignment problem, which is a key issue for many parts of the brain. In the cerebellum, detailed knowledge not only of the local circuitry connectivity but also of the topography of different sources of afferent/external information makes this problem particularly tractable. In addition, multiple forms of synaptic plasticity and their general rules of induction have been identified. In this review, we will discuss the possible roles of synaptic and cellular plasticity at specific locations in contributing to behavioral changes. Focus will be on the parts of the cerebellum that are devoted to limb control, which constitute a large proportion of the cortex and where the knowledge of the external connectivity is particularly well known. From this perspective, a number of sites of synaptic plasticity appear to primarily have the function of balancing the overall level of activity in the cerebellar circuitry, whereas the locations at which synaptic plasticity leads to functional changes in terms of limb control are more limited. Specifically, the postsynaptic forms of long-term potentiation (LTP) and long-term depression (LTD) at the parallel fiber synapses made on interneurons and Purkinje cells, respectively, are the types of plasticity that mediate the widest associative capacity and the tightest link between the synaptic change and the external functions that are to be controlled. PMID:25417189
Lexical stress assignment as a problem of probabilistic inference.
Jouravlev, Olessia; Lupker, Stephen J
2015-10-01
A new conceptualization of the process of stress assignment, couched in the principles of (Bayesian) probabilistic inference, is introduced in this paper. According to this approach, in deciding where to place stress in a polysyllabic word, a reader estimates the posterior probabilities of alternative stress patterns. This estimation is accomplished by adjusting a prior belief about the likelihoods of alternative stress patterns (derived from experience with the distribution of stress patterns in the language) by using lexical and non-lexical sources of evidence for stress derived from the orthographic input. The proposed theoretical framework was used to compute probabilities of stress patterns for Russian disyllabic words and nonwords which were then compared with the performance of readers. The results showed that the estimated probabilities of stress patterns were reflective of actual stress assignment performance and of naming latencies, suggesting that the mechanisms that are involved in the process of stress assignment might indeed be inferentially-based. PMID:25636917
Solving the assignment problem using continuous-time and discrete-time improved dual networks.
Hu, Xiaolin; Wang, Jun
2012-05-01
The assignment problem is an archetypal combinatorial optimization problem. In this brief, we present a continuous-time version and a discrete-time version of the improved dual neural network (IDNN) for solving the assignment problem. Compared with most assignment networks in the literature, the two versions of IDNNs are advantageous in circuit implementation due to their simple structures. Both of them are theoretically guaranteed to be globally convergent to a solution of the assignment problem if only the solution is unique. PMID:24806130
Competitive neural architecture for hardware solution to the assignment problem
NASA Technical Reports Server (NTRS)
Eberhardt, S. P.; Daud, T.; Kerns, D. A.; Brown, T. X.; Thakoor, A. P.
1991-01-01
The architecture for competitive assignment is described with attention given to the VLSI design and critical circuits fabricated in complementary metal-oxide semiconductor. The local application of association costs to processing units reduces the connectivity to the number of VLSI-compatible processing units. 'Hysteretic annealing' is discussed and when compared to mean-field annealing is found to enhance processing-unit gain and provide near-optimal solutions in about 150 microsec.
A New Approach for Assigning Individually Prescribed Problems.
ERIC Educational Resources Information Center
Kawasaki, Zenshiro
1979-01-01
Describes an automatic exercise-problem selection method which is based on the theory of Learning Diagnosis and Treatment (LDT). An optimum problem for each learner is identified by comparing the required readiness for the problem and the learner's mastery level. (Author/CMV)
ERIC Educational Resources Information Center
Billington, Eric J.; Skinner, Christopher H.
2006-01-01
Results from nine experiments were analyzed to evaluate the relationship between relative problem completion rates (RPCR) and judgments of time involving mathematics assignments. For each experiment, control assignments contained only target mathematics computation or word problems. Matched experimental assignments contained similar target…
Simulated annealing algorithm for solving chambering student-case assignment problem
NASA Astrophysics Data System (ADS)
Ghazali, Saadiah; Abdul-Rahman, Syariza
2015-12-01
The problem related to project assignment problem is one of popular practical problem that appear nowadays. The challenge of solving the problem raise whenever the complexity related to preferences, the existence of real-world constraints and problem size increased. This study focuses on solving a chambering student-case assignment problem by using a simulated annealing algorithm where this problem is classified under project assignment problem. The project assignment problem is considered as hard combinatorial optimization problem and solving it using a metaheuristic approach is an advantage because it could return a good solution in a reasonable time. The problem of assigning chambering students to cases has never been addressed in the literature before. For the proposed problem, it is essential for law graduates to peruse in chambers before they are qualified to become legal counselor. Thus, assigning the chambering students to cases is a critically needed especially when involving many preferences. Hence, this study presents a preliminary study of the proposed project assignment problem. The objective of the study is to minimize the total completion time for all students in solving the given cases. This study employed a minimum cost greedy heuristic in order to construct a feasible initial solution. The search then is preceded with a simulated annealing algorithm for further improvement of solution quality. The analysis of the obtained result has shown that the proposed simulated annealing algorithm has greatly improved the solution constructed by the minimum cost greedy heuristic. Hence, this research has demonstrated the advantages of solving project assignment problem by using metaheuristic techniques.
Achieving spectrum conservation for the minimum-span and minimum-order frequency assignment problems
NASA Technical Reports Server (NTRS)
Heyward, Ann O.
1992-01-01
Effective and efficient solutions of frequency assignment problems assumes increasing importance as the radiofrequency spectrum experiences ever increasing utilization by diverse communications services, requiring that the most efficient use of this resource be achieved. The research presented explores a general approach to the frequency assignment problem, in which such problems are categorized by the appropriate spectrum conserving objective function, and are each treated as an N-job, M-machine scheduling problem appropriate for the objective. Results obtained and presented illustrate that such an approach presents an effective means of achieving spectrum conserving frequency assignments for communications systems in a variety of environments.
An integer programming model for gate assignment problem at airline terminals
NASA Astrophysics Data System (ADS)
Chun, Chong Kok; Nordin, Syarifah Zyurina
2015-05-01
In this paper, we concentrate on a gate assignment problem (GAP) at the airlines terminal. Our problem is to assign an arrival plane to a suitable gate. There are two considerations needed to take. One of its is passenger walking distance from arrival gate to departure gate while another consideration is the transport baggage distance from one gate to another. Our objective is to minimize the total distance between the gates that related to assign the arrival plane to the suitable gates. An integer linear programming (ILP) model is proposed to solve this gate assignment problem. We also conduct a computational experiment using CPLEX 12.1 solver in AIMMS 3.10 software to analyze the performance of the model. Results of the computational experiments are presented. The efficiency of flights assignment is depends on the ratio of the weight for both total passenger traveling distances and total baggage transport distances.
Successive linear optimization approach to the dynamic traffic assignment problem
Ho, J.K.
1980-11-01
A dynamic model for the optimal control of traffic flow over a network is considered. The model, which treats congestion explicitly in the flow equations, gives rise to nonlinear, nonconvex mathematical programming problems. It has been shown for a piecewise linear version of this model that a global optimum is contained in the set of optimal solutions of a certain linear program. A sufficient condition for optimality which implies that a global optimum can be obtained by successively optimizing at most N + 1 objective functions for the linear program, where N is the number of time periods in the planning horizon is presented. Computational results are reported to indicate the efficiency of this approach.
Evaluation of a Brief Homework Assignment Designed to Reduce Citation Problems
ERIC Educational Resources Information Center
Schuetze, Pamela
2004-01-01
I evaluated a brief homework assignment designed to reduce citation problems in research-based term papers. Students in 2 developmental psychology classes received a brief presentation and handout defining plagiarism with tips on how to cite sources to avoid plagiarizing. In addition, students in 1 class completed 2 brief homework assignments in…
Parallel shortest augmenting path algorithm for the assignment problem. Technical report
Balas, E.; Miller, D.; Pekny, J.; Toth, P.
1989-04-01
We describe a parallel version of the shortest augmenting path algorithm for the assignment problem. While generating the initial dual solution and partial assignment in parallel does not require substantive changes in the sequential algorithm, using several augmenting paths in parallel does require a new dual variable recalculation method. The parallel algorithm was tested on a 14-processor Butterfly Plus computer, on problems with up to 900 million variables. The speedup obtained increases with problem size. The algorithm was also embedded into a parallel branch and bound procedure for the traveling salesman problem on a directed graph, which was tested on the Butterfly Plus on problems involving up to 7,500 cities. To our knowledge, these are the largest assignment problems and traveling salesman problems solved so far.
Heuristic algorithms for a storage location assignment problem in a chaotic warehouse
NASA Astrophysics Data System (ADS)
Quintanilla, Sacramento; Pérez, Ángeles; Ballestín, Francisco; Lino, Pilar
2015-10-01
The extensive application of emerging technologies is revolutionizing warehouse management. These technologies facilitate working with complex and powerful warehouse management models in which products do not have assigned fixed locations (random storage). Random storage allows the utilization of the available space to be optimized. In this context, and motivated by a real problem, this article presents a model that looks for the optimal allocation of goods in order to maximize the storage space availability within the restrictions of the warehouse. For the proposed model a construction method, a local search algorithm and different metaheuristics have been developed. The introduced algorithms can also be used for other purposes such as to assess when and how it is convenient to perform relocation of stored items to improve the current level of storage space availability. Computational tests performed on a set of randomly generated and real warehouse instances show the effectiveness of the proposed methods.
NASA Astrophysics Data System (ADS)
Mukherjee, Sathi; Basu, Kajla
2010-10-01
In this paper we develop a methodology to solve the multiple attribute assignment problems where the attributes are considered to be Intuitionistic Fuzzy Sets (IFS). We apply the concept of similarity measures of IFS to solve the Intuitionistic Fuzzy Multi-Attribute Assignment Problem (IFMAAP). The weights of the attributes are determined from expert opinion. An illustrative example is solved to verify the developed approach and to demonstrate its practicality.
On scheduling models for the frequency interval assignment problem with cumulative interferences
NASA Astrophysics Data System (ADS)
Kiatmanaroj, Kata; Artigues, Christian; Houssin, Laurent
2016-05-01
In this article, models and methods for solving a real-life frequency assignment problem based on scheduling theory are investigated. A realistic frequency assignment problem involving cumulative interference constraints in which the aim is to maximize the number of assigned users is considered. If interferences are assumed to be binary, a multiple carrier frequency assignment problem can be treated as a disjunctive scheduling problem since a user requesting a number of contiguous frequencies can be considered as a non-preemptive task with a processing time, and two interfering users can be modelled through a disjunctive constraint on the corresponding tasks. A binary interference version of the problem is constructed and a disjunctive scheduling model is derived. Based on the binary representation, two models are proposed. The first one relies on an interference matrix and the second one considers maximal cliques. A third, cumulative, model that yields a new class of scheduling problems is also proposed. Computational experiments show that the case-study frequency assignment problem can be solved efficiently with disjunctive scheduling techniques.
Wang, Zhaocai; Pu, Jun; Cao, Liling; Tan, Jian
2015-01-01
The unbalanced assignment problem (UAP) is to optimally resolve the problem of assigning n jobs to m individuals (m < n), such that minimum cost or maximum profit obtained. It is a vitally important Non-deterministic Polynomial (NP) complete problem in operation management and applied mathematics, having numerous real life applications. In this paper, we present a new parallel DNA algorithm for solving the unbalanced assignment problem using DNA molecular operations. We reasonably design flexible-length DNA strands representing different jobs and individuals, take appropriate steps, and get the solutions of the UAP in the proper length range and O(mn) time. We extend the application of DNA molecular operations and simultaneity to simplify the complexity of the computation. PMID:26512650
Wang, Zhaocai; Pu, Jun; Cao, Liling; Tan, Jian
2015-01-01
The unbalanced assignment problem (UAP) is to optimally resolve the problem of assigning n jobs to m individuals (m < n), such that minimum cost or maximum profit obtained. It is a vitally important Non-deterministic Polynomial (NP) complete problem in operation management and applied mathematics, having numerous real life applications. In this paper, we present a new parallel DNA algorithm for solving the unbalanced assignment problem using DNA molecular operations. We reasonably design flexible-length DNA strands representing different jobs and individuals, take appropriate steps, and get the solutions of the UAP in the proper length range and O(mn) time. We extend the application of DNA molecular operations and simultaneity to simplify the complexity of the computation. PMID:26512650
Qualls, Joseph; Russomanno, David J.
2011-01-01
The lack of knowledge models to represent sensor systems, algorithms, and missions makes opportunistically discovering a synthesis of systems and algorithms that can satisfy high-level mission specifications impractical. A novel ontological problem-solving framework has been designed that leverages knowledge models describing sensors, algorithms, and high-level missions to facilitate automated inference of assigning systems to subtasks that may satisfy a given mission specification. To demonstrate the efficacy of the ontological problem-solving architecture, a family of persistence surveillance sensor systems and algorithms has been instantiated in a prototype environment to demonstrate the assignment of systems to subtasks of high-level missions. PMID:22164081
ERIC Educational Resources Information Center
Newby, Michael; Nguyen, ThuyUyen H.
2010-01-01
This paper examines the effectiveness of a technique that first appeared as a Teaching Tip in the Journal of Information Systems Education. In this approach the same problem is used in every programming assignment within a course, but the students are required to use different programming techniques. This approach was used in an intermediate C++…
A tabu search approach for the NMR protein structure-based assignment problem.
Cavuşlar, Gizem; Çatay, Bülent; Apaydın, Mehmet Serkan
2012-01-01
Spectroscopy is an experimental technique which exploits the magnetic properties of specific nuclei and enables the study of proteins in solution. The key bottleneck of NMR studies is to map the NMR peaks to corresponding nuclei, also known as the assignment problem. Structure-Based Assignment (SBA) is an approach to solve this computationally challenging problem by using prior information about the protein obtained from a homologous structure. NVR-BIP used the Nuclear Vector Replacement (NVR) framework to model SBA as a binary integer programming problem. In this paper, we prove that this problem is NP-hard and propose a tabu search (TS) algorithm (NVR-TS) equipped with a guided perturbation mechanism to efficiently solve it. NVR-TS uses a quadratic penalty relaxation of NVR-BIP where the violations in the Nuclear Overhauser Effect constraints are penalized in the objective function. Experimental results indicate that our algorithm finds the optimal solution on NVRBIP’s data set which consists of seven proteins with 25 templates (31 to 126 residues). Furthermore, it achieves relatively high assignment accuracies on two additional large proteins, MBP and EIN (348 and 243 residues, respectively), which NVR-BIP failed to solve. The executable and the input files are available for download at http://people.sabanciuniv.edu/catay/NVR-TS/NVR-TS.html. PMID:23221084
Applying genetic algorithms to the state assignment problem: a case study
NASA Astrophysics Data System (ADS)
Amaral, Jose N.; Tumer, Kagan; Ghosh, Joydeep
1992-08-01
Finding the best state assignment for implementing a synchronous sequential circuit is important for reducing silicon area or chip count in many digital designs. This State Assignment Problem (SAP) belongs to a broader class of combinatorial optimization problems than the well studied traveling salesman problem, which can be formulated as a special case of SAP. The search for a good solution is considerably more involved for the SAP than it is for the traveling salesman problem due to a much larger number of equivalent solutions, and no effective heuristic has been found so far to cater to all types of circuits. In this paper, a matrix representation is used as the genotype for a Generic Algorithm (GA) approach to this problem. A novel selection mechanism is introduced, and suitable genetic operators for crossover and mutation, are constructed. The properties of each of these elements of the GA are discussed and an analysis of parameters that influence the algorithm is given. A canonical form for a solution is defined to significantly reduce the search space and number of local minima. Simulation results for scalable examples show that the GA approach yields results that are comparable to those obtained using competing heuristics. Although a GA does not seem to be the tool of choice for use in a sequential Von-Neumann machine, the results obtained are good enough to encourage further research on distributed processing GA machines that can exploit its intrinsic parallelism.
An analysis of spectral envelope-reduction via quadratic assignment problems
NASA Technical Reports Server (NTRS)
George, Alan; Pothen, Alex
1994-01-01
A new spectral algorithm for reordering a sparse symmetric matrix to reduce its envelope size was described. The ordering is computed by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. In this paper, we provide an analysis of the spectral envelope reduction algorithm. We described related 1- and 2-sum problems; the former is related to the envelope size, while the latter is related to an upper bound on the work involved in an envelope Cholesky factorization scheme. We formulate the latter two problems as quadratic assignment problems, and then study the 2-sum problem in more detail. We obtain lower bounds on the 2-sum by considering a projected quadratic assignment problem, and then show that finding a permutation matrix closest to an orthogonal matrix attaining one of the lower bounds justifies the spectral envelope reduction algorithm. The lower bound on the 2-sum is seen to be tight for reasonably 'uniform' finite element meshes. We also obtain asymptotically tight lower bounds for the envelope size for certain classes of meshes.
System analysis of global space power problem
NASA Astrophysics Data System (ADS)
Latyshev, Leonid
A brief discussion of Space Power System development problems is presented. Topics covered include the following: solar energy utilization; solar energy concentrators and receivers; solar electric power plants; thermonuclear electric power plants; energy transmission; and lunar bases.
Federal Register 2010, 2011, 2012, 2013, 2014
2012-11-26
... COMMISSION Preoperational Testing of Onsite Electric Power Systems To Verify Proper Load Group Assignments... for public comment draft regulatory guide (DG), DG-1294, ``Preoperational Testing of On-Site Electric... encompass preoperational testing of electrical power systems used to meet current Station...
NASA Technical Reports Server (NTRS)
Voigt, Kerstin
1992-01-01
We present MENDER, a knowledge based system that implements software design techniques that are specialized to automatically compile generate-and-patch problem solvers that satisfy global resource assignments problems. We provide empirical evidence of the superior performance of generate-and-patch over generate-and-test: even with constrained generation, for a global constraint in the domain of '2D-floorplanning'. For a second constraint in '2D-floorplanning' we show that even when it is possible to incorporate the constraint into a constrained generator, a generate-and-patch problem solver may satisfy the constraint more rapidly. We also briefly summarize how an extended version of our system applies to a constraint in the domain of 'multiprocessor scheduling'.
Short communication : a linear assignment approach for the least-squares protein morphing problem.
Anitescu, M.; Park, S.; Mathematics and Computer Science
2009-02-01
This work addresses the computation of free-energy differences between protein conformations by using morphing (i.e., transformation) of a source conformation into a target conformation. To enhance the morphing procedure, we employ permutations of atoms: we seek to find the permutation s that minimizes the mean-square distance traveled by the atoms. Instead of performing this combinatorial search in the space of permutations, we show that the best permutation can be found by solving a linear assignment problem. We demonstrate that the use of such optimal permutations significantly improves the efficiency of the free-energy computation.
NASA Astrophysics Data System (ADS)
Mont, Alexander D.; Calderon, Christopher P.; Poore, Aubrey B.
2014-06-01
We present a new approach to estimating the probability of each association in a 2D assignment problem defined by likelihood ratios. Our method divides the set of feasible hypotheses into clusters, and converts a collection of hypotheses into a collection of clusters containing them, reducing the variance of the estimate. Simulations show that our method often generates substantially more accurate probability estimates in less time than traditional methods. Our method can obtain reasonably accurate probabilities of association based on only the input cost matrix and single best candidate solution, eliminating the need for a K-best solution method or MCMC sampling.
A neural network-based optimization algorithm for the weapon-target assignment problem
Wacholder, E.
1989-02-01
A neural network-based algorithm was developed for the Weapon-Target Assignment Problem (WTAP) in Ballistic Missile Defense (BMD). An optimal assignment policy is one which allocates targets to weapon platforms such that the total expected leakage value of targets surviving the defense is minimized. This involves the minimization of a non-linear objective function subject to inequality constraints specifying the maximum number of interceptors available to each platform and the maximum number of interceptors allowed to be fired at each target as imposed by the Battle Management/Command Control and Communications (BM/C/sup 3/) system. The algorithm consists of solving a system of ODEs trajectories and variables. Simulations of the algorithm on PC and VAX computers were carried out using a simple numerical scheme. In all the battle instances tested, the algorithm has proven to be stable and to converge to solutions very close to global optima. The time to achieve convergence was consistently less than the time constant of the network's processing elements (neurons). This implies that fast solutions can be realized if the algorithm is implemented in hardware circuits. Three series of battle scenarios are analyzed and discussed in this report. Input data and results are presented in detail. The main advantage of this algorithm is that it can be adapted to either a special-purpose hardware circuit or a general-purpose concurrent machine to yield fast and accurate solutions to difficult decision problems. 40 refs., 8 figs., 8 tabs.
A Genetic Algorithm Approach for the TV Self-Promotion Assignment Problem
NASA Astrophysics Data System (ADS)
Pereira, Paulo A.; Fontes, Fernando A. C. C.; Fontes, Dalila B. M. M.
2009-09-01
We report on the development of a Genetic Algorithm (GA), which has been integrated into a Decision Support System to plan the best assignment of the weekly self-promotion space for a TV station. The problem addressed consists on deciding which shows to advertise and when such that the number of viewers, of an intended group or target, is maximized. The GA proposed incorporates a greedy heuristic to find good initial solutions. These solutions, as well as the solutions later obtained through the use of the GA, go then through a repair procedure. This is used with two objectives, which are addressed in turn. Firstly, it checks the solution feasibility and if unfeasible it is fixed by removing some shows. Secondly, it tries to improve the solution by adding some extra shows. Since the problem faced by the commercial TV station is too big and has too many features it cannot be solved exactly. Therefore, in order to test the quality of the solutions provided by the proposed GA we have randomly generated some smaller problem instances. For these problems we have obtained solutions on average within 1% of the optimal solution value.
NASA Astrophysics Data System (ADS)
Delmelle, Eric M.; Thill, Jean-Claude; Peeters, Dominique; Thomas, Isabelle
2014-07-01
In rapidly growing urban areas, it is deemed vital to expand (or contract) an existing network of public facilities to meet anticipated changes in the level of demand. We present a multi-period capacitated median model for school network facility location planning that minimizes transportation costs, while functional costs are subject to a budget constraint. The proposed Vintage Flexible Capacitated Location Problem (ViFCLP) has the flexibility to account for a minimum school-age closing requirement, while the maximum capacity of each school can be adjusted by the addition of modular units. Non-closest assignments are controlled by the introduction of a parameter penalizing excess travel. The applicability of the ViFCLP is illustrated on a large US school system (Charlotte-Mecklenburg, North Carolina) where high school demand is expected to grow faster with distance to the city center. Higher school capacities and greater penalty on travel impedance parameter reduce the number of non-closest assignments. The proposed model is beneficial to policy makers seeking to improve the provision and efficiency of public services over a multi-period planning horizon.
Study on MAX-MIN Ant System with Random Selection in Quadratic Assignment Problem
NASA Astrophysics Data System (ADS)
Iimura, Ichiro; Yoshida, Kenji; Ishibashi, Ken; Nakayama, Shigeru
Ant Colony Optimization (ACO), which is a type of swarm intelligence inspired by ants' foraging behavior, has been studied extensively and its effectiveness has been shown by many researchers. The previous studies have reported that MAX-MIN Ant System (MMAS) is one of effective ACO algorithms. The MMAS maintains the balance of intensification and diversification concerning pheromone by limiting the quantity of pheromone to the range of minimum and maximum values. In this paper, we propose MAX-MIN Ant System with Random Selection (MMASRS) for improving the search performance even further. The MMASRS is a new ACO algorithm that is MMAS into which random selection was newly introduced. The random selection is one of the edgechoosing methods by agents (ants). In our experimental evaluation using ten quadratic assignment problems, we have proved that the proposed MMASRS with the random selection is superior to the conventional MMAS without the random selection in the viewpoint of the search performance.
Lim, Wee Loon; Wibowo, Antoni; Desa, Mohammad Ishak; Haron, Habibollah
2016-01-01
The quadratic assignment problem (QAP) is an NP-hard combinatorial optimization problem with a wide variety of applications. Biogeography-based optimization (BBO), a relatively new optimization technique based on the biogeography concept, uses the idea of migration strategy of species to derive algorithm for solving optimization problems. It has been shown that BBO provides performance on a par with other optimization methods. A classical BBO algorithm employs the mutation operator as its diversification strategy. However, this process will often ruin the quality of solutions in QAP. In this paper, we propose a hybrid technique to overcome the weakness of classical BBO algorithm to solve QAP, by replacing the mutation operator with a tabu search procedure. Our experiments using the benchmark instances from QAPLIB show that the proposed hybrid method is able to find good solutions for them within reasonable computational times. Out of 61 benchmark instances tested, the proposed method is able to obtain the best known solutions for 57 of them. PMID:26819585
Lim, Wee Loon; Wibowo, Antoni; Desa, Mohammad Ishak; Haron, Habibollah
2016-01-01
The quadratic assignment problem (QAP) is an NP-hard combinatorial optimization problem with a wide variety of applications. Biogeography-based optimization (BBO), a relatively new optimization technique based on the biogeography concept, uses the idea of migration strategy of species to derive algorithm for solving optimization problems. It has been shown that BBO provides performance on a par with other optimization methods. A classical BBO algorithm employs the mutation operator as its diversification strategy. However, this process will often ruin the quality of solutions in QAP. In this paper, we propose a hybrid technique to overcome the weakness of classical BBO algorithm to solve QAP, by replacing the mutation operator with a tabu search procedure. Our experiments using the benchmark instances from QAPLIB show that the proposed hybrid method is able to find good solutions for them within reasonable computational times. Out of 61 benchmark instances tested, the proposed method is able to obtain the best known solutions for 57 of them. PMID:26819585
The Lebanese electric power system operational problems
Yehia, M.; Saidi, M.; Diab, H.; Kabalan, K. )
1991-09-01
This article deals with the analysis of the existing practical problems in the Lebanese electric power system and provides guidelines for future research and strategies for solving the operational problems which are now facing the system. These problems are partly due, first, to the socioeconomic situation in Lebanon after 14 years of a devastating war and second, to the particularity of the Lebanese system.
Meta-Heuristic Combining Prior Online and Offline Information for the Quadratic Assignment Problem.
Sun, Jianyong; Zhang, Qingfu; Yao, Xin
2014-03-01
The construction of promising solutions for NP-hard combinatorial optimization problems (COPs) in meta-heuristics is usually based on three types of information, namely a priori information, a posteriori information learned from visited solutions during the search procedure, and online information collected in the solution construction process. Prior information reflects our domain knowledge about the COPs. Extensive domain knowledge can surely make the search effective, yet it is not always available. Posterior information could guide the meta-heuristics to globally explore promising search areas, but it lacks local guidance capability. On the contrary, online information can capture local structures, and its application can help exploit the search space. In this paper, we studied the effects of using this information on metaheuristic's algorithmic performances for the COPs. The study was illustrated by a set of heuristic algorithms developed for the quadratic assignment problem. We first proposed an improved scheme to extract online local information, then developed a unified framework under which all types of information can be combined readily. Finally, we studied the benefits of the three types of information to meta-heuristics. Conclusions were drawn from the comprehensive study, which can be used as principles to guide the design of effective meta-heuristic in the future. PMID:23757559
Computer Power. Part 2: Electrical Power Problems and Their Amelioration.
ERIC Educational Resources Information Center
Price, Bennett J.
1989-01-01
Describes electrical power problems that affect computer users, including spikes, sags, outages, noise, frequency variations, and static electricity. Ways in which these problems may be diagnosed and cured are discussed. Sidebars consider transformers; power distribution units; surge currents/linear and non-linear loads; and sizing the power…
Community-powered problem solving.
Gouillart, Francis; Billings, Douglas
2013-04-01
Traditionally, companies have managed their constituencies with specific processes: marketing to customers, procuring from vendors, developing HR policies for employees, and so on. The problem is, such processes focus on repeatability and compliance, so they can lead to stagnation. Inviting your constituencies to collectively help you solve problems and exploit opportunities--"co-creation"--is a better approach. It allows you to continually tap the skills and insights of huge numbers of stakeholders and develop new ways to produce value for all. The idea is to provide stakeholders with platforms (physical and digital forums) on which they can interact, get them to start exploring new experiences and connections, and let the system grow organically. A co-creation initiative by a unit of Becton, Dickinson and Company demonstrates how this works. A global leader in syringes, BD set out to deepen its ties with hospital customers and help them reduce the incidence of infections from unsafe injection and syringe disposal practices. The effort began with a cross-functional internal team, brought in the hospital procurement and supply managers BD had relationships with, and then reached out to hospitals' infection-prevention and occupational health leaders. Eventually product designers, nurses, sustainability staffers, and even hospital CFOs were using the platform, contributing data that generated new best practices and reduced infections. PMID:23593769
A new approach on auxiliary vehicle assignment in capacitated location routing problem
NASA Astrophysics Data System (ADS)
Bashiri, Mahdi; Rasoulinejad, Zeinab; Fallahzade, Ehsan
2016-03-01
The location routing problem (LRP) considers locating depots and vehicle routing decisions simultaneously. In classic LRP the number of customers in each route depends on the capacity of the vehicle. In this paper a capacitated LRP model with auxiliary vehicle assignment is presented in which the length of each route is not restricted by main vehicle capacity. Two kinds of vehicles are considered: main vehicles with higher capacity and fixed cost and auxiliary vehicles with lower capacity and fixed cost. The auxiliary vehicles can be added to the transportation system as an alternative strategy to cover the capacity limitations and they are just used to transfer goods from depots to vehicles and cannot serve the customers by themselves. To show the applicability of the proposed model, some numerical examples derived from the well-known instances are used. Moreover the model has been solved by some meta-heuristics for large sized instances. The results show the efficiency of the proposed model and the solution approach, considering the classic model and the exact solution approach, respectively.
Power Assigning Method for Increasing the Number of Users in Time-spreading Optical CDMA Systems
NASA Astrophysics Data System (ADS)
Salehi, Mohammad Reza; Abiri, Ebrahim; Kazemi, Keyvan; Dezfouli, Mehran
2011-04-01
In this paper, a method for increasing the number of supportable users in a time-spreading Optical code division multiple access (OCDMA) system is proposed. In the presented technique, a unique codeword is assigned to a couple of users instead of just one. Different optical powers are employed for such users in order to distinguish them from each other. Other methods use the frequency or the polarization of the optical signals as an additional coding dimension to increase the number of codewords and hence the number of users in the network. It is proposed to employ nonlinear optical regenerators for separating optical pulses with different powers. A comprehensive design algorithm for such regenerators is presented. In order to evaluate the performance of the designed regenerators a TS-OCDMA system is simulated using OptiSystem software. Results indicate an error free transmission in the system employing the proposed technique.
ERIC Educational Resources Information Center
Williams, Julie Ann Stuart; Reid, Randall C.
2010-01-01
The authors describe how to structure a memo format for homework assignments in which a manager requests analysis of a particular issue from the student. The student must respond with a memo stating a recommendation and describing the solution approach. The results from using the memo format include improved student performance and professional…
Nuclear Power: Problems in Information Management.
ERIC Educational Resources Information Center
Beaver, William
1990-01-01
Discusses the problems encountered at the Duquesne Light Company of Pittsburgh's nuclear power plant as the result of an inability to process information effectively and keep pace with technological change. The creation of a separate division trained and directed to manage the plant's information flows is described and evaluated. (CLB)
NASA Astrophysics Data System (ADS)
Lin, Yi-Kuei; Yeh, Cheng-Ta
2013-03-01
Many real-life systems, such as computer systems, manufacturing systems and logistics systems, are modelled as stochastic-flow networks (SFNs) to evaluate network reliability. Here, network reliability, defined as the probability that the network successfully transmits d units of data/commodity from an origin to a destination, is a performance indicator of the systems. Network reliability maximization is a particular objective, but is costly for many system supervisors. This article solves the multi-objective problem of reliability maximization and cost minimization by finding the optimal component assignment for SFN, in which a set of multi-state components is ready to be assigned to the network. A two-stage approach integrating Non-dominated Sorting Genetic Algorithm II and simple additive weighting are proposed to solve this problem, where network reliability is evaluated in terms of minimal paths and recursive sum of disjoint products. Several practical examples related to computer networks are utilized to demonstrate the proposed approach.
Agnetis, Alessandro; Coppi, Alberto; Corsini, Matteo; Dellino, Gabriella; Meloni, Carlo; Pranzo, Marco
2014-03-01
This research aims at supporting hospital management in making prompt Operating Room (OR) planning decisions, when either unpredicted events occur or alternative scenarios or configurations need to be rapidly evaluated. We design and test a planning tool enabling managers to efficiently analyse several alternatives to the current OR planning and scheduling. To this aim, we propose a decomposition approach. More specifically, we first focus on determining the Master Surgical Schedule (MSS) on a weekly basis, by assigning the different surgical disciplines to the available sessions. Next, we allocate surgeries to each session, focusing on elective patients only. Patients are selected from the waiting lists according to several parameters, including surgery duration, waiting time and priority class of the operations. We performed computational experiments to compare the performance of our decomposition approach with an (exact) integrated approach. The case study selected for our simulations is based on the characteristics of the operating theatre (OT) of a medium-size public Italian hospital. Scalability of the method is tested for different OT sizes. A pilot example is also proposed to highlight the usefulness of our approach for decision support. The proposed decomposition approach finds satisfactory solutions with significant savings in computation time. PMID:23783452
ERIC Educational Resources Information Center
Teixeira, Jennifer; Holman, R. W.
2008-01-01
Organic chemistry students typically struggle with the retrosynthetic approach to solving synthesis problems because most textbooks present the chemistry grouped by "reactions of the functional group". In contrast, the retrosynthetic approach requires the student to envision "reactions that yield the functional group". A second challenge is the…
Power of Peer Review: An Online Collaborative Learning Assignment in Social Psychology
ERIC Educational Resources Information Center
Cathey, Christie
2007-01-01
In a semester-long, peer review assignment, undergraduates enrolled in a social psychology course wrote essays that applied course concepts to life experiences. Students anonymously posted essays for the entire class to view, and peers posted commentaries on classmates' essays using an online discussion board. Students rated the assignment as…
NASA Astrophysics Data System (ADS)
Xu, Shuo; Ji, Ze; Truong Pham, Duc; Yu, Fan
2011-11-01
The simultaneous mission assignment and home allocation for hospital service robots studied is a Multidimensional Assignment Problem (MAP) with multiobjectives and multiconstraints. A population-based metaheuristic, the Binary Bees Algorithm (BBA), is proposed to optimize this NP-hard problem. Inspired by the foraging mechanism of honeybees, the BBA's most important feature is an explicit functional partitioning between global search and local search for exploration and exploitation, respectively. Its key parts consist of adaptive global search, three-step elitism selection (constraint handling, non-dominated solutions selection, and diversity preservation), and elites-centred local search within a Hamming neighbourhood. Two comparative experiments were conducted to investigate its single objective optimization, optimization effectiveness (indexed by the S-metric and C-metric) and optimization efficiency (indexed by computational burden and CPU time) in detail. The BBA outperformed its competitors in almost all the quantitative indices. Hence, the above overall scheme, and particularly the searching history-adapted global search strategy was validated.
NASA Astrophysics Data System (ADS)
Said, Tkatek; Otman, Abdoun; Jaafar, Abouchabaka; Najat, Rafalia
2013-09-01
The aim of this work is to present a meta-heuristically approach of the spatial assignment problem of human resources in multi-sites enterprise. Usually, this problem consists to move employees from one site to another based on one or more criteria. Our goal in this new approach is to improve the quality of service and performance of all sites with maximizing an objective function under some managers imposed constraints. The formulation presented here of this problem coincides perfectly with a Combinatorial Optimization Problem (COP) which is in the most cases NP-hard to solve optimally. To avoid this difficulty, we have opted to use a meta-heuristic popular method, which is the genetic algorithm, to solve this problem in concrete cases. The results obtained have shown the effectiveness of our approach, which remains until now very costly in time. But the reduction of the time can be obtained by different ways that we plan to do in the next work.
NASA Astrophysics Data System (ADS)
Bashiri, Mahdi; Karimi, Hossein
2012-07-01
Quadratic assignment problem (QAP) is a well-known problem in the facility location and layout. It belongs to the NP-complete class. There are many heuristic and meta-heuristic methods, which are presented for QAP in the literature. In this paper, we applied 2-opt, greedy 2-opt, 3-opt, greedy 3-opt, and VNZ as heuristic methods and tabu search (TS), simulated annealing, and particle swarm optimization as meta-heuristic methods for the QAP. This research is dedicated to compare the relative percentage deviation of these solution qualities from the best known solution which is introduced in QAPLIB. Furthermore, a tuning method is applied for meta-heuristic parameters. Results indicate that TS is the best in 31%of QAPs, and the IFLS method, which is in the literature, is the best in 58 % of QAPs; these two methods are the same in 11 % of test problems. Also, TS has a better computational time among heuristic and meta-heuristic methods.
ERIC Educational Resources Information Center
Forsberg, Lucas
2007-01-01
Most previous research on parental involvement in children's homework has focused on the pedagogical advantages or disadvantages of school assignments while neglecting the practice in its social context, family life. By studying parent-child homework negotiations in Swedish families, this paper examines how family members position themselves and…
NASA Astrophysics Data System (ADS)
Kawamura, Tetsuo; Horio, Yoshihiko; Hasegawa, Mikio
The tabu search was implemented on a neural network with chaotic neuro-dynamics. This chaotic exponential tabu search shows great performance in solving quadratic assignment problems (QAPs). To exploit inherent parallel processing abilities of analog hardware systems, a synchronous updating scheme, where all the neurons in the network are updated at the same time, was proposed. However, several neurons may fire simultaneously with the synchronous updating. As a result, we cannot determine only one candidate for the 2-opt exchange from the many fired neurons. To solve this problem, several neuron selection methods, which select one specific neuron among the fired neurons, were proposed. These neuron selection methods improved the performance of the synchronous updating scheme. In this paper, we analyze the dynamics of the chaotic neural network with the neuron selection methods by means of the spatial and temporal mutual information. Through the analyses, the network solution search dynamics of the exponential chaotic tabu search with different neuron selection methods are evaluated.
ERIC Educational Resources Information Center
Natriello, Gary; And Others
By studying the process by which disadvantaged and low-achieving high school students are assigned to classes and special programs, how and why disadvantaged students are placed in inappropriate programs can be understood. Reasons exist to question the assumption that students are assigned to programs rationally on the basis of information about…
Problem free nuclear power and global change
Teller, E.; Wood, L.; Nuckolls, J.; Ishikawa, M.; Hyde, R.
1997-08-15
Nuclear fission power reactors represent a solution-in-principle to all aspects of global change possibly induced by inputting of either particulate or carbon or sulfur oxides into the Earth`s atmosphere. Of proven technological feasibility, they presently produce high- grade heat for electricity generation, space heating and industrial process-driving around the world, without emitting greenhouse gases or atmospheric particulates. However, a substantial number of major issues currently stand between nuclear power implemented with light- water reactors and widespread substitution for large stationary fossil fuel-fired systems, including long-term fuel supply, adverse public perceptions regarding both long-term and acute operational safety, plant decommissioning, fuel reprocessing, radwaste disposal, fissile materials diversion to military purposes and - perhaps more seriously - cost. We describe a GW-scale, high-temperature nuclear reactor heat source that can operate with no human intervention for a few decades and that may be widely acceptable, since its safety features are simple, inexpensive and easily understood. We provide first-level details of a reactor system designed to satisfy these requirements. Such a back-solving approach to realizing large-scale nuclear fission power systems potentially leads to an energy source capable of meeting all large-scale stationary demands for high- temperature heat. If widely employed to support such demands, it could, for example, directly reduce present-day world-wide CO{sub 2} emissions by two-fold; by using it to produce non-carbonaceous fuels for small mobile demands, a second two-fold reduction could be attained. Even the first such reduction would permit continued slow power-demand growth in the First World and rapid development of the Third World, both without any governmental suppression of fossil fuel usage.
Energy Crisis: Environmental Issue Exacerbates Power Supply Problem
ERIC Educational Resources Information Center
Boffey, Philip M.
1970-01-01
Analyzes problems of providing sufficient electrical power in terms of inefficiency of industry and of the conflict between need for power and need for environmental quality. Suggests ways of slowing the growth in demand, and indicates needed research into energy production. (EB)
ERIC Educational Resources Information Center
Falk, Gideon; Falk, Shoshana
1981-01-01
Groups (N=62) of four members each used a multiple role-playing technique under three conditions: majority rule, unanimity rule, or no assigned decision rule. Results suggested that assignment of a majority rule has greater potential for reducing power inequalities. Discusses changes in members' self-perceived power. (Author/RC)
Artificial Bee Colony Algorithm for Solving Optimal Power Flow Problem
Le Dinh, Luong; Vo Ngoc, Dieu
2013-01-01
This paper proposes an artificial bee colony (ABC) algorithm for solving optimal power flow (OPF) problem. The objective of the OPF problem is to minimize total cost of thermal units while satisfying the unit and system constraints such as generator capacity limits, power balance, line flow limits, bus voltages limits, and transformer tap settings limits. The ABC algorithm is an optimization method inspired from the foraging behavior of honey bees. The proposed algorithm has been tested on the IEEE 30-bus, 57-bus, and 118-bus systems. The numerical results have indicated that the proposed algorithm can find high quality solution for the problem in a fast manner via the result comparisons with other methods in the literature. Therefore, the proposed ABC algorithm can be a favorable method for solving the OPF problem. PMID:24470790
Artificial bee colony algorithm for solving optimal power flow problem.
Le Dinh, Luong; Vo Ngoc, Dieu; Vasant, Pandian
2013-01-01
This paper proposes an artificial bee colony (ABC) algorithm for solving optimal power flow (OPF) problem. The objective of the OPF problem is to minimize total cost of thermal units while satisfying the unit and system constraints such as generator capacity limits, power balance, line flow limits, bus voltages limits, and transformer tap settings limits. The ABC algorithm is an optimization method inspired from the foraging behavior of honey bees. The proposed algorithm has been tested on the IEEE 30-bus, 57-bus, and 118-bus systems. The numerical results have indicated that the proposed algorithm can find high quality solution for the problem in a fast manner via the result comparisons with other methods in the literature. Therefore, the proposed ABC algorithm can be a favorable method for solving the OPF problem. PMID:24470790
Shelton, Michael; Gerfen, Chip; Palma, Nicolás Gutiérrez
2012-01-01
This study employs a naming task to examine the role of the syllable in speech production, focusing on a lesser-studied aspect of syllabic processing, the interaction of subsyllabic patterns (i.e. syllable phonotactics) and higher-level prosody, in this case, stress assignment in Spanish. Specifically, we examine a controversial debate in Spanish regarding the interaction of syllable weight and stress placement, showing that traditional representations of weight fail to predict the differential modulation of stress placement by rising versus falling diphthongs in Spanish nonce forms. Our results also suggest that the internal structure of the syllable plays a larger role than is assumed in the processing literature in that it modulates higher-level processes such as stress encoding. Our results thus inform the debate regarding syllable weight in Spanish and linguistic theorizing more broadly, as well as expand our understanding of the importance of the syllable, and more specifically its internal structure, in modulating word processing. PMID:23264712
Extension of modified power method to two-dimensional problems
NASA Astrophysics Data System (ADS)
Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung
2016-09-01
In this study, the generalized modified power method was extended to two-dimensional problems. A direct application of the method to two-dimensional problems was shown to be unstable when the number of requested eigenmodes is larger than a certain problem dependent number. The root cause of this instability has been identified as the degeneracy of the transfer matrix. In order to resolve this instability, the number of sub-regions for the transfer matrix was increased to be larger than the number of requested eigenmodes; and a new transfer matrix was introduced accordingly which can be calculated by the least square method. The stability of the new method has been successfully demonstrated with a neutron diffusion eigenvalue problem and the 2D C5G7 benchmark problem.
Polynomial Kernels for 3-Leaf Power Graph Modification Problems
NASA Astrophysics Data System (ADS)
Bessy, Stéphane; Paul, Christophe; Perez, Anthony
A graph G = (V,E) is a 3-leaf power iff there exists a tree T the leaf set of which is V and such that (u,v) ∈ E iff u and v are at distance at most 3 in T. The 3-leaf power edge modification problems, i.e. edition (also known as the CLOSEST 3-LEAF POWER), completion and edge-deletion are FPT when parameterized by the size of the edge set modification. However, a polynomial kernel was known for none of these three problems. For each of them, we provide a kernel with O(k 3) vertices that can be computed in linear time. We thereby answer an open question first mentioned by Dom, Guo, Hüffner and Niedermeier [9].
Nuclear power plant alarm systems: Problems and issues
O'Hara, J.M.; Brown, W.S.
1991-01-01
Despite the incorporation of advanced technology into nuclear power plant alarm systems, human factors problems remain. This paper identifies to be addressed in order to allow advanced technology to be used effectively in the design of nuclear power plant alarm systems. The operator's use and processing of alarm system information will be considered. Based upon a review of alarm system research, issues related to general system design, alarm processing, display and control are discussed. It is concluded that the design of effective alarm systems depends on an understanding of the information processing capabilities and limitations of the operator. 39 refs.
Cundell, Diana R
2002-05-01
Educators are increasingly being encouraged to use more active- and problem-based-learning techniques and assignments in the classroom to improve critical and analytical thinking skills. Active learning-based courses have been purported to be more time consuming than traditional lecture methods and for many instructors have therefore proven difficult to include in many one-semester science courses. To address this problem, a series of assignments was developed for use in a basic microbiology course involving sophomore-, junior-, and senior-level students from five different biology majors (environmental science, biology, biochemistry, premedicine, and physician assistant). Writing assignments included global, historical, and social themes for which a standardized grading format was established. Students also participated in a class debate in which the merits of the living microbial kingdoms were discussed, with only one kingdom being saved from an imaginary global catastrophe. Traditional lectures were facilitated by the use of a dedicated note packet developed by the instructor and specific for course content. Laboratories involved group analysis of mini-case history studies involving pathogenic microbes. Students' perceptions of the subject were assessed using an exit questionnaire sent to 100 of the 174 students who had taken the course during the 5-year time period. The majority of the 64 students who responded were sophomores (78%), in keeping with the target audience, and their perception of the course's challenge level was significantly higher (p < 0.03, 8.7) than their junior and senior counterparts (7.9). Students rated the most useful learning tools as case history studies (9.4) and the class debate (9.1), with the introduction of a dedicated microbiology links web page to the University website representing the sole component resulting in a statistically significant increase in students' perceptions of the importance of the course (p < 0.03). PMID
Verduzco-Flores, Sergio O.; O'Reilly, Randall C.
2015-01-01
We present a cerebellar architecture with two main characteristics. The first one is that complex spikes respond to increases in sensory errors. The second one is that cerebellar modules associate particular contexts where errors have increased in the past with corrective commands that stop the increase in error. We analyze our architecture formally and computationally for the case of reaching in a 3D environment. In the case of motor control, we show that there are synergies of this architecture with the Equilibrium-Point hypothesis, leading to novel ways to solve the motor error and distal learning problems. In particular, the presence of desired equilibrium lengths for muscles provides a way to know when the error is increasing, and which corrections to apply. In the context of Threshold Control Theory and Perceptual Control Theory we show how to extend our model so it implements anticipative corrections in cascade control systems that span from muscle contractions to cognitive operations. PMID:25852535
Investigation of valve failure problems in LWR power plants
1980-04-01
An analysis of component failures from information in the computerized Nuclear Safety Information Center (NSIC) data bank shows that for both PWR and BWR plants the component category most responsible for approximately 19.3% of light water reactor (LWR) power plant shutdowns. This investigation by Burns and Roe, Inc. shows that the greatest cause of shutdowns in LWRs due to valve failures is leakage from valve stem packing. Both BWR plants and PWR plants have stem leakage problems (BWRs, 21% and PWRs, 34%).
ERIC Educational Resources Information Center
McLeod, Alan M., Ed.
1982-01-01
Although the focus of this issue of the "Virginia English Bulletin" is on making effective assignments, most of the articles also emphasize the importance and power of writing. Articles deal with the following topics: (1) the use of I-search (as explained by Kenneth Macrorie in "Searching Writing") as a form of research paper that narrates the…
ERIC Educational Resources Information Center
Parkhurst, John T.; Fleisher, Matthew S.; Skinner, Christopher H.; Woehr, David J.; Hawthorn-Embree, Meredith L.
2011-01-01
After completing the Multidimensional Work-Ethic Profile (MWEP), 98 college students were given a 20-problem math computation assignment and instructed to stop working on the assignment after completing 10 problems. Next, they were allowed to choose to finish either the partially completed assignment that had 10 problems remaining or a new…
ERIC Educational Resources Information Center
Dong, Nianbo
2014-01-01
For intervention studies involving binary treatment variables, procedures for power analysis have been worked out and computerized estimation tools are generally available. The purpose of this study is to: (1) develop the statistical formulations for calculating statistical power, minimum detectable effect size (MDES) and its confidence interval,…
ERIC Educational Resources Information Center
Cundell, Diana R.
2002-01-01
Reports on the development of a series of assignments for use in a basic microbiology course involving sophomore-, junior-, and senior-level students from five different biology majors. Assignments include writing, a class debate, and case history studies. (Author/MM)
Local Dynamic Reactive Power for Correction of System Voltage Problems
Kueck, John D; Rizy, D Tom; Li, Fangxing; Xu, Yan; Li, Huijuan; Adhikari, Sarina; Irminger, Philip
2008-12-01
Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results
ERIC Educational Resources Information Center
Vick, John W.; Houden, Dorothy
This report contains recommendations of a Wisconsin Task Assignment Steering Committee created to explore solutions to some significant problems facing adult chronic "revolving-detox-door" alcohol abusers (CRA's), persons with repeated admissions for detoxification services; and to examine the system that serves and funds them. This report is…
Mighty Mathematicians: Using Problem Posing and Problem Solving to Develop Mathematical Power
ERIC Educational Resources Information Center
McGatha, Maggie B.; Sheffield, Linda J.
2006-01-01
This article describes a year-long professional development institute combined with a summer camp for students. Both were designed to help teachers and students develop their problem-solving and problem-posing abilities.
Power Plays: Problems with Empowerment in a Critical Pedagogy
ERIC Educational Resources Information Center
Lund, Darren E.
2005-01-01
In response to a Critical Notice published in these pages by Roberts (Vol. 32/1,2001), this article notes several specific reservations with regard to Shor's model of empowerment as outlined in "When Students Have Power" (1996). The original book documents one critical educator's attempts at negotiating power in a college classroom setting. While…
Singularity problems of the power law for modeling creep compliance
NASA Technical Reports Server (NTRS)
Dillard, D. A.; Hiel, C.
1985-01-01
An explanation is offered for the extreme sensitivity that has been observed in the power law parameters of the T300/934 graphite epoxy material systems during experiments to evaluate the system's viscoelastic response. It is shown that the singularity associated with the power law can explain the sensitivity as well as the observed variability in the calculated parameters. Techniques for minimizing errors are suggested.
High power free-electron laser concepts and problems
Goldstein, J.C.
1995-03-01
Free-electron lasers (FELs) have long been thought to offer the potential of high average power operation. That potential exists because of several unique properties of FELs, such as the removal of ``waste heat`` at the velocity of light, the ``laser medium`` (the electron beam) is impervious to damage by very high optical intensitites, and the technology of generating very high average power relativistic electron beams. In particular, if one can build a laser with a power extraction efficiency 11 which is driven by an electron beam of average Power P{sub EB}, one expects a laser output power of P{sub L} = {eta} P{sub EB}. One approach to FEL devices with large values of {eta} (in excess of 10 %) is to use a ``tapered`` (or nonuniform) wiggler. This approach was followed at several laboratories during the FEL development Program for the Strategic Defense Initiative (SDI) project. In this paper, we review some concepts and technical requirements for high-power tapered-wiggler FELs driven by radio-frequency linear accelerators (rf-linacs) which were developed during the SDI project. Contributions from three quite different technologies - rf-accelerators, optics, and magnets - are needed to construct and operate an FEL oscillator. The particular requirements on these technologies for a high-power FEL were far beyond the state of the art in those areas when the SDI project started, so significant advances had to be made before a working device could be constructed. Many of those requirements were not clearly understood when the project started, but were developed during the course of the experimental and theoretical research for the project. This information can be useful in planning future high-power FEL projects.
Problems and outlooks for petrothermal power engineering ( review)
NASA Astrophysics Data System (ADS)
Alekseenko, S. V.; Borodulin, V. Yu.; Gnatus, N. A.; Nizovtsev, M. I.; Smirnova, N. N.
2016-01-01
A review is given for the state of the art and future development of the geothermal power engineering. Different diagrams of GeoPP are shown for different levels of geofluid temperature. A special focus is made on challenges for petrothermal power production. The huge amount of heat from petrothermal resources can be harnessed through creating geothermal circulation systems within the dry rocks. Estimates for system lifetime and heat production capacity of circulation systems are given for different flow rates of coolant.
Automated protein NMR resonance assignments.
Wan, Xiang; Xu, Dong; Slupsky, Carolyn M; Lin, Guohui
2003-01-01
NMR resonance peak assignment is one of the key steps in solving an NMR protein structure. The assignment process links resonance peaks to individual residues of the target protein sequence, providing the prerequisite for establishing intra- and inter-residue spatial relationships between atoms. The assignment process is tedious and time-consuming, which could take many weeks. Though there exist a number of computer programs to assist the assignment process, many NMR labs are still doing the assignments manually to ensure quality. This paper presents (1) a new scoring system for mapping spin systems to residues, (2) an automated adjacency information extraction procedure from NMR spectra, and (3) a very fast assignment algorithm based on our previous proposed greedy filtering method and a maximum matching algorithm to automate the assignment process. The computational tests on 70 instances of (pseudo) experimental NMR data of 14 proteins demonstrate that the new score scheme has much better discerning power with the aid of adjacency information between spin systems simulated across various NMR spectra. Typically, with automated extraction of adjacency information, our method achieves nearly complete assignments for most of the proteins. The experiment shows very promising perspective that the fast automated assignment algorithm together with the new score scheme and automated adjacency extraction may be ready for practical use. PMID:16452794
Negotiating Assignment Pathways: Students and Academic Assignments
ERIC Educational Resources Information Center
McDowell, Liz
2008-01-01
Existing research identifies that students' approaches to assignments are related to their general approaches to study. It is suggested that students need to better understand the requirements of assignments and acquire new concepts such as "argument". This fine-grained study proposes four qualitatively distinct assignment pathways: gathering,…
Composition, Philosophy, and Rhetoric: The "Problem of Power."
ERIC Educational Resources Information Center
Sebberson, David
1993-01-01
Remarks on moments in Louise Wetherbee Phelps' book "Composition as a Human Science" where the absence of power presents a problematic for composition. Presents Jurgen Habermas for and against Phelps, noting the gestures of both authors against scientism while drawing on several of Habermas' basic concepts. Proposes rereading Aristotle's…
Prospects for solving environmental problems pertinent to thermal power stations
NASA Astrophysics Data System (ADS)
Tumanovskii, A. G.; Kotler, V. R.
2007-06-01
Possible ways to protect the atmosphere and water basin against harmful emissions and effluent waters discharged from thermal power stations are considered. Data on the effectiveness of different methods for removing NO x , SO2, and ash particles, as well as heavy metals and CO2, from these emissions and discharges are presented.
Problem Manual for Power Processing, Part 1. Electric Machinery Analysis.
ERIC Educational Resources Information Center
Hamilton, Howard B.
This publication was developed as a portion of a two-semester sequence commencing at either the sixth or seventh term of the undergraduate program in electrical engineering at the University of Pittsburgh. The materials of the two courses, produced by a National Science Foundation grant, are concerned with power conversion systems comprising power…
Space power technology applied to the energy problem
NASA Technical Reports Server (NTRS)
Miller, J. L.; Morgan, J. R.
1977-01-01
A solution to the energy problem is suggested through the technology of photovoltaic electrolysis of water to generate hydrogen. Efficient solar devices are discussed in relation to available solar energy, and photovoltaic energy cost. It is concluded that photovoltaic electrolytic generation of hydrogen will be economically feasible in 1985.
47 CFR 74.702 - Channel assignments.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...
47 CFR 74.702 - Channel assignments.
Code of Federal Regulations, 2012 CFR
2012-10-01
..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...
47 CFR 74.702 - Channel assignments.
Code of Federal Regulations, 2014 CFR
2014-10-01
..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...
47 CFR 74.702 - Channel assignments.
Code of Federal Regulations, 2010 CFR
2010-10-01
..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...
47 CFR 74.702 - Channel assignments.
Code of Federal Regulations, 2013 CFR
2013-10-01
..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.702 Channel assignments. (a) An applicant for a new low power TV or TV translator... standard VHF Channels (2 to 13 inclusive) may be assigned to a VHF low power TV or TV translator...
ERIC Educational Resources Information Center
Xin, Ziqiang; Zhang, Li
2009-01-01
The present study explored whether first and second order cognitive holding power perceived by children in mathematical classrooms, fluid intelligence, and mathematical achievement predicted their performance on standard problems, and especially realistic problems. A sample of 119 Chinese 4-6th graders were administered the word problem test, the…
Electric power scheduling - A distributed problem-solving approach
NASA Technical Reports Server (NTRS)
Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.
1990-01-01
Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity.
ERIC Educational Resources Information Center
Parlante, Nick
2001-01-01
Describes a Web site called Nifty Assignments that offers assignments for computer science education. Topics include programming assignments; student appeal; appropriateness for high school classes; and links to other related Web sites. (LRW)
Schmidhuber, Jürgen
2013-01-01
Most of computer science focuses on automatically solving given computational problems. I focus on automatically inventing or discovering problems in a way inspired by the playful behavior of animals and humans, to train a more and more general problem solver from scratch in an unsupervised fashion. Consider the infinite set of all computable descriptions of tasks with possibly computable solutions. Given a general problem-solving architecture, at any given time, the novel algorithmic framework PowerPlay (Schmidhuber, 2011) searches the space of possible pairs of new tasks and modifications of the current problem solver, until it finds a more powerful problem solver that provably solves all previously learned tasks plus the new one, while the unmodified predecessor does not. Newly invented tasks may require to achieve a wow-effect by making previously learned skills more efficient such that they require less time and space. New skills may (partially) re-use previously learned skills. The greedy search of typical PowerPlay variants uses time-optimal program search to order candidate pairs of tasks and solver modifications by their conditional computational (time and space) complexity, given the stored experience so far. The new task and its corresponding task-solving skill are those first found and validated. This biases the search toward pairs that can be described compactly and validated quickly. The computational costs of validating new tasks need not grow with task repertoire size. Standard problem solver architectures of personal computers or neural networks tend to generalize by solving numerous tasks outside the self-invented training set; PowerPlay’s ongoing search for novelty keeps breaking the generalization abilities of its present solver. This is related to Gödel’s sequence of increasingly powerful formal theories based on adding formerly unprovable statements to the axioms without affecting previously provable theorems. The continually increasing
Schmidhuber, Jürgen
2013-01-01
Most of computer science focuses on automatically solving given computational problems. I focus on automatically inventing or discovering problems in a way inspired by the playful behavior of animals and humans, to train a more and more general problem solver from scratch in an unsupervised fashion. Consider the infinite set of all computable descriptions of tasks with possibly computable solutions. Given a general problem-solving architecture, at any given time, the novel algorithmic framework PowerPlay (Schmidhuber, 2011) searches the space of possible pairs of new tasks and modifications of the current problem solver, until it finds a more powerful problem solver that provably solves all previously learned tasks plus the new one, while the unmodified predecessor does not. Newly invented tasks may require to achieve a wow-effect by making previously learned skills more efficient such that they require less time and space. New skills may (partially) re-use previously learned skills. The greedy search of typical PowerPlay variants uses time-optimal program search to order candidate pairs of tasks and solver modifications by their conditional computational (time and space) complexity, given the stored experience so far. The new task and its corresponding task-solving skill are those first found and validated. This biases the search toward pairs that can be described compactly and validated quickly. The computational costs of validating new tasks need not grow with task repertoire size. Standard problem solver architectures of personal computers or neural networks tend to generalize by solving numerous tasks outside the self-invented training set; PowerPlay's ongoing search for novelty keeps breaking the generalization abilities of its present solver. This is related to Gödel's sequence of increasingly powerful formal theories based on adding formerly unprovable statements to the axioms without affecting previously provable theorems. The continually increasing
47 CFR 74.802 - Frequency assignment.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... MHz. All zones 113 km (70 miles) (c) Specific frequency operation is required when operating...
47 CFR 74.802 - Frequency assignment.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 47 Telecommunication 4 2011-10-01 2011-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... MHz. All zones 113 km (70 miles) (c) Specific frequency operation is required when operating...
47 CFR 74.802 - Frequency assignment.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 47 Telecommunication 4 2014-10-01 2014-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... MHz. All zones 113 km (70 miles) (c) Specific frequency operation is required when operating...
47 CFR 74.802 - Frequency assignment.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 47 Telecommunication 4 2013-10-01 2013-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... MHz. All zones 113 km (70 miles) (c) Specific frequency operation is required when operating...
47 CFR 74.802 - Frequency assignment.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 47 Telecommunication 4 2012-10-01 2012-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... MHz. All zones 113 km (70 miles) (c) Specific frequency operation is required when operating...
Electric power scheduling: A distributed problem-solving approach
NASA Technical Reports Server (NTRS)
Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.
1990-01-01
Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity. The value-driven free-market economic model is such a tool.
Data bases for rapid response to power reactor problems
Maskewitz, B.F.
1980-01-01
The urgency of the TMI-2 incident demanded prompt answers to an imperious situation. In responding to these challenging circumstances, both government and industry recognized deficiencies in both availability of essential retrievable data and calculational capabilities designed to respond immediately to actual abnormal events. Each responded by initiating new programs to provide a remedy for the deficiencies and to generally improve all safety measures in the nuclear power industry. Many data bases and information centers offer generic data and other technology resources which are generally useful in support of nuclear safety programs. A few centers can offer rapid access to calculational methods and associated data and more will make an effort to do so. As a beneficial spin-off from the lessons learned from TMI-2, more technical effort and financial resources will be devoted to the prevention of accidents, and to improvement of safety measures in the immediate future and for long term R and D programs by both government and the nuclear power industry.
Research and Design Problems Introduced by Increased Power Output
NASA Technical Reports Server (NTRS)
Kurtz, Oskar
1937-01-01
In what follows the question of the number and geometrical arrangement of the cylinders so important in the design of high performance power units will be considered from various points of view. A discussion will be given of the possibilities of the various working processes and an investigation will be made of possible means for improving the continuous operation and take-off performance, particularly the methods of supercharging, increasing the r.p.m., and employing the two-stroke-cycle engine. Finally, the question of lowered fuel consumption will be gone over briefly. The subject will be treated under four headings: I) Considerations on the engine layout; II) Increase in output per given swept volume; III) Improvement in the take-off performance; IV) Lowering of the fuel consumption.
Is EIA part of the wind power planning problem?
Smart, Duncan Ewan; Stojanovic, Timothy A. Warren, Charles R.
2014-11-15
This research evaluates the importance and effectiveness of Environmental Impact Assessment (EIA) within wind farm planning debates, drawing on insights from case studies in Scotland. Despite general public support for renewable energy on the grounds that it is needed to tackle climate change and implement sustainable development, many proposed wind farms encounter significant resistance. The importance of planning issues and (EIA) processes has arguably been overlooked within recent wind farm social acceptability discourse. Through semi-structured interviews with key stakeholders and textual analysis of EIA documents, the characteristics of EIA are assessed in terms of its perceived purpose and performance. The data show that whilst respondents perceive EIA to be important, they express concerns about bias and about the inability of EIA to address climate change and wind farm decommissioning issues adequately. Furthermore, the research identifies key issues which impede the effectiveness of EIA, and reveals differences between theoretical and practical framings of EIA. The paper questions the assumption that EIA is a universally applicable tool, and argues that its effectiveness should be analysed in the context of specific development sectors. The article concludes by reviewing whether the recently amended EIA Directive (2014/52/EU) could resolve identified problems within national EIA practice. - Highlights: • Evaluation of EIA for onshore wind farm planning in Scotland. • EIA is important for multiple aspects of onshore wind farm planning. • Multiple substantive deficiencies of relevance to wind farm planning exist in EIA. • Further research into EIA effectiveness for specific development types is required. • Directive 2014/52/EU may improve EIA effectiveness within wind farm planning.
Fleet Assignment Using Collective Intelligence
NASA Technical Reports Server (NTRS)
Antoine, Nicolas E.; Bieniawski, Stefan R.; Kroo, Ilan M.; Wolpert, David H.
2004-01-01
Product distribution theory is a new collective intelligence-based framework for analyzing and controlling distributed systems. Its usefulness in distributed stochastic optimization is illustrated here through an airline fleet assignment problem. This problem involves the allocation of aircraft to a set of flights legs in order to meet passenger demand, while satisfying a variety of linear and non-linear constraints. Over the course of the day, the routing of each aircraft is determined in order to minimize the number of required flights for a given fleet. The associated flow continuity and aircraft count constraints have led researchers to focus on obtaining quasi-optimal solutions, especially at larger scales. In this paper, the authors propose the application of this new stochastic optimization algorithm to a non-linear objective cold start fleet assignment problem. Results show that the optimizer can successfully solve such highly-constrained problems (130 variables, 184 constraints).
Solving LFC problem in an interconnected power system using superconducting magnetic energy storage
NASA Astrophysics Data System (ADS)
Farahani, Mohsen; Ganjefar, Soheil
2013-04-01
This paper proposes the combination of a load frequency control (LFC) with superconducting magnetic energy storage (SMES) to solve the LFC problem in interconnected power systems. By using this combination, the speed damping of frequency and tie-line power flow deviations is considerably increased. A new control strategy of SMES is proposed in this paper. The problem of determining optimal parameters of PID and SMES control loop is considered as an optimization problem and a pattern search algorithm (PS) optimization is employed to solve it. The simulation results show that if an SMES unit is installed in an interconnected power system, in addition to eliminating oscillations and deviations, the settling time in the frequency and tie-line power flow responses is considerably reduced.
Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System
NASA Astrophysics Data System (ADS)
Bhende, C. N.; Kalam, A.; Malla, S. G.
2016-04-01
Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.
Afonin, Andrei V; Pavlov, Dmitry V; Ushakov, Igor A; Keiko, Natalia A
2012-07-01
In the (13) C NMR spectra of methylglyoxal bisdimethylhydrazone, the (13) C-5 signal is shifted to higher frequencies, while the (13) C-6 signal is shifted to lower frequencies on going from the EE to ZE isomer following the trend found previously. Surprisingly, the (1) H-6 chemical shift and (1) J(C-6,H-6) coupling constant are noticeably larger in the ZE isomer than in the EE isomer, although the configuration around the -CH═N- bond does not change. This paradox can be rationalized by the C-H⋯N intramolecular hydrogen bond in the ZE isomer, which is found from the quantum-chemical calculations including Bader's quantum theory of atoms in molecules analysis. This hydrogen bond results in the increase of δ((1) H-6) and (1) J(C-6,H-6) parameters. The effect of the C-H⋯N hydrogen bond on the (1) H shielding and one-bond (13) C-(1) H coupling complicates the configurational assignment of the considered compound because of these spectral parameters. The (1) H, (13) C and (15) N chemical shifts of the 2- and 8-(CH(3) )(2) N groups attached to the -C(CH(3) )═N- and -CH═N- moieties, respectively, reveal pronounced difference. The ab initio calculations show that the 8-(CH(3) )(2) N group conjugate effectively with the π-framework, and the 2-(CH(3) )(2) N group twisted out from the plane of the backbone and loses conjugation. As a result, the degree of charge transfer from the N-2- and N-8- nitrogen lone pairs to the π-framework varies, which affects the (1) H, (13) C and (15) N shieldings. PMID:22615146
ERIC Educational Resources Information Center
Hashimoto, I.
1986-01-01
Suggests, on a humorous note, a game-plan for assignment justification and elaboration that utilizes, in a constructive and professional manner, the best of what is known about assignment-making. (EL)
Benestan, Laura; Gosselin, Thierry; Perrier, Charles; Sainte-Marie, Bernard; Rochette, Rémy; Bernatchez, Louis
2015-07-01
Deciphering genetic structure and inferring connectivity in marine species have been challenging due to weak genetic differentiation and limited resolution offered by traditional genotypic methods. The main goal of this study was to assess how a population genomics framework could help delineate the genetic structure of the American lobster (Homarus americanus) throughout much of the species' range and increase the assignment success of individuals to their location of origin. We genotyped 10 156 filtered SNPs using RAD sequencing to delineate genetic structure and perform population assignment for 586 American lobsters collected in 17 locations distributed across a large portion of the species' natural distribution range. Our results revealed the existence of a hierarchical genetic structure, first separating lobsters from the northern and southern part of the range (FCT = 0.0011; P-value = 0.0002) and then revealing a total of 11 genetically distinguishable populations (mean FST = 0.00185; CI: 0.0007-0.0021, P-value < 0.0002), providing strong evidence for weak, albeit fine-scale population structuring within each region. A resampling procedure showed that assignment success was highest with a subset of 3000 SNPs having the highest FST . Applying Anderson's (Molecular Ecology Resources, 2010, 10, 701) method to avoid 'high-grading bias', 94.2% and 80.8% of individuals were correctly assigned to their region and location of origin, respectively. Lastly, we showed that assignment success was positively associated with sample size. These results demonstrate that using a large number of SNPs improves fine-scale population structure delineation and population assignment success in a context of weak genetic structure. We discuss the implications of these findings for the conservation and management of highly connected marine species, particularly regarding the geographic scale of demographic independence. PMID:25977167
A review of vibration problems in power station boiler feed pumps
NASA Technical Reports Server (NTRS)
France, David
1994-01-01
Boiler feed pump reliability and availability is recognized as important to the overall efficiency of power generation. Vibration monitoring is often used as a part of planned maintenance. This paper reviews a number of different types of boiler feed pump vibration problems describing some methods of solution in the process. It is hoped that this review may assist both designers and users faced with similar problems.
Behavior of 1 Ω resistors at frequencies below 1 Hz and the problem of assigning a dc value
NASA Astrophysics Data System (ADS)
Fletcher, Nick; Götz, Martin; Rolland, Benjamin; Pesel, Eckart
2015-08-01
This paper presents a systematic study of the effects of reversals of current polarity on 1 Ω standard resistors. A selection of 1 Ω standards were measured on a dc cryogenic current comparator bridge and also on an ac current comparator bridge operating at 1 Hz. We find that the apparent 4 terminal resistance depends strongly on the dc reversal rate, in one case showing a variation of more than 0.1 μΩ/Ω for cycle times between 10 s and 1000 s. Even in the best cases, effects of at least 0.01 μΩ/Ω are present. Furthermore, the assumption that the apparent resistance value converges to a limiting value for long waiting times after reversal is not always upheld, making it difficult to quote a simple dc value. Existing models of Peltier heating at wire junctions do not completely explain our observations. The problems presented have been the limiting factor for 1 Ω measurements as part of a recent on-site comparison of quantum Hall effect resistance standards.
Otero, José; Palacios, Ana; Suárez, Rosario; Junco, Luis
2014-01-01
When selecting relevant inputs in modeling problems with low quality data, the ranking of the most informative inputs is also uncertain. In this paper, this issue is addressed through a new procedure that allows the extending of different crisp feature selection algorithms to vague data. The partial knowledge about the ordinal of each feature is modelled by means of a possibility distribution, and a ranking is hereby applied to sort these distributions. It will be shown that this technique makes the most use of the available information in some vague datasets. The approach is demonstrated in a real-world application. In the context of massive online computer science courses, methods are sought for automatically providing the student with a qualification through code metrics. Feature selection methods are used to find the metrics involved in the most meaningful predictions. In this study, 800 source code files, collected and revised by the authors in classroom Computer Science lectures taught between 2013 and 2014, are analyzed with the proposed technique, and the most relevant metrics for the automatic grading task are discussed. PMID:25114967
Otero, José; Palacios, Ana; Suárez, Rosario; Junco, Luis; Couso, Inés; Sánchez, Luciano
2014-01-01
When selecting relevant inputs in modeling problems with low quality data, the ranking of the most informative inputs is also uncertain. In this paper, this issue is addressed through a new procedure that allows the extending of different crisp feature selection algorithms to vague data. The partial knowledge about the ordinal of each feature is modelled by means of a possibility distribution, and a ranking is hereby applied to sort these distributions. It will be shown that this technique makes the most use of the available information in some vague datasets. The approach is demonstrated in a real-world application. In the context of massive online computer science courses, methods are sought for automatically providing the student with a qualification through code metrics. Feature selection methods are used to find the metrics involved in the most meaningful predictions. In this study, 800 source code files, collected and revised by the authors in classroom Computer Science lectures taught between 2013 and 2014, are analyzed with the proposed technique, and the most relevant metrics for the automatic grading task are discussed. PMID:25114967
NASA Astrophysics Data System (ADS)
Yaakob, Shamshul Bahar; Watada, Junzo
In this paper, a hybrid neural network approach to solve mixed integer quadratic bilevel programming problems is proposed. Bilevel programming problems arise when one optimization problem, the upper problem, is constrained by another optimization, the lower problem. The mixed integer quadratic bilevel programming problem is transformed into a double-layered neural network. The combination of a genetic algorithm (GA) and a meta-controlled Boltzmann machine (BM) enables us to formulate a hybrid neural network approach to solving bilevel programming problems. The GA is used to generate the feasible partial solutions of the upper level and to provide the parameters for the lower level. The meta-controlled BM is employed to cope with the lower level problem. The lower level solution is transmitted to the upper level. This procedure enables us to obtain the whole upper level solution. The iterative processes can converge on the complete solution of this problem to generate an optimal one. The proposed method leads the mixed integer quadratic bilevel programming problem to a global optimal solution. Finally, a numerical example is used to illustrate the application of the method in a power system environment, which shows that the algorithm is feasible and advantageous.
Mixed-integer programming methods for transportation and power generation problems
NASA Astrophysics Data System (ADS)
Damci Kurt, Pelin
This dissertation conducts theoretical and computational research to solve challenging problems in application areas such as supply chain and power systems. The first part of the dissertation studies a transportation problem with market choice (TPMC) which is a variant of the classical transportation problem in which suppliers with limited capacities have a choice of which demands (markets) to satisfy. We show that TPMC is strongly NP-complete. We consider a version of the problem with a service level constraint on the maximum number of markets that can be rejected and show that if the original problem is polynomial, its cardinality-constrained version is also polynomial. We propose valid inequalities for mixed-integer cover and knapsack sets with variable upper bound constraints, which appear as substructures of TPMC and use them in a branch-and-cut algorithm to solve this problem. The second part of this dissertation studies a unit commitment (UC) problem in which the goal is to minimize the operational cost of power generators over a time period subject to physical constraints while satisfying demand. We provide several exponential classes of multi-period ramping and multi-period variable upper bound inequalities. We prove the strength of these inequalities and describe polynomial-time separation algorithms. Computational results show the effectiveness of the proposed inequalities when used as cuts in a branch-and-cut algorithm to solve the UC problem. The last part of this dissertation investigates the effects of uncertain wind power on the UC problem. A two-stage robust model and a three-stage stochastic program are compared.
Efficient Credit Assignment through Evaluation Function Decomposition
NASA Technical Reports Server (NTRS)
Agogino, Adrian; Turner, Kagan; Mikkulainen, Risto
2005-01-01
Evolutionary methods are powerful tools in discovering solutions for difficult continuous tasks. When such a solution is encoded over multiple genes, a genetic algorithm faces the difficult credit assignment problem of evaluating how a single gene in a chromosome contributes to the full solution. Typically a single evaluation function is used for the entire chromosome, implicitly giving each gene in the chromosome the same evaluation. This method is inefficient because a gene will get credit for the contribution of all the other genes as well. Accurately measuring the fitness of individual genes in such a large search space requires many trials. This paper instead proposes turning this single complex search problem into a multi-agent search problem, where each agent has the simpler task of discovering a suitable gene. Gene-specific evaluation functions can then be created that have better theoretical properties than a single evaluation function over all genes. This method is tested in the difficult double-pole balancing problem, showing that agents using gene-specific evaluation functions can create a successful control policy in 20 percent fewer trials than the best existing genetic algorithms. The method is extended to more distributed problems, achieving 95 percent performance gains over tradition methods in the multi-rover domain.
Using Cognitive Science to Assign Test Weights.
ERIC Educational Resources Information Center
Bhaskar, R.; Dillard, Jesse F.
1983-01-01
Description of an objective method for assigning weights to questions on examinations includes discussions of classical test theory, knowledge organization, and how task analysis can be used to identify knowledge elements required to solve specific problems, rank them, and assign objective weights to exam questions using a Pareto distribution (7…
Scaling Preference Data for Program Assignments.
ERIC Educational Resources Information Center
Carifio, James
The present study devised a computerized assignment-by-preference algorithm for a ninth-grade exploratory curriculum. The problem addressed was one of maximally mapping all students into 8 of 12 vocational programs in terms of their preferences for studying each of the programs and the assignment restrictions established by the school. To minimize…
Fuel cells provide a revenue-generating solution to power quality problems
King, J.M. Jr.
1996-03-01
Electric power quality and reliability are becoming increasingly important as computers and microprocessors assume a larger role in commercial, health care and industrial buildings and processes. At the same time, constraints on transmission and distribution of power from central stations are making local areas vulnerable to low voltage, load addition limitations, power quality and power reliability problems. Many customers currently utilize some form of premium power in the form of standby generators and/or UPS systems. These include customers where continuous power is required because of health and safety or security reasons (hospitals, nursing homes, places of public assembly, air traffic control, military installations, telecommunications, etc.) These also include customers with industrial or commercial processes which can`t tolerance an interruption of power because of product loss or equipment damage. The paper discusses the use of the PC25 fuel cell power plant for backup and parallel power supplies for critical industrial applications. Several PC25 installations are described: the use of propane in a PC25; the use by rural cooperatives; and a demonstration of PC25 technology using landfill gas.
Colston, B.W.; Brehm, R.L.
1985-01-01
The anticipated growth of the space station power requirement provides a good example of the problem the space nuclear power supply developers have to contend with: should a reactor power supply be developed that attempts to be all things to all missions, i.e., is highly flexible in its ability to meet a wide variety of missions, or should the development of a reactor system await a specific mission definition and be customized to this mission. This leads, of course, to a chicken-and-egg situation. For power requirements of several hundreds of kilowatts or more, no nuclear power source exists or is even far enough along in the definition stage (much less the development stage) for NASA to reasonably assume probable availability within the next 10 years. The real problem of space nuclear power is this ''chicken-and-egg'' syndrome: DOE will not develop a space reactor system for NASA without a firm mission, and NASA will not specify a firm mission requiring a space reactor because such a system doesn't exist and is perceived not to be developable within the time frame of the mission. The problem is how to break this cycle. The SP-100 program has taken an important first step to breaking this cycle, but this program is much more design-specific than what is required to achieve a broad technology base and latitude in achievable power level. In contrast to the SP-100 approach, a wider perspective is required: the development of the appropriate technologies for power levels can be broken into ranges, say, from 100 kWe to 1000 kWe, and from 1000 kWe to 10,000 kWe.
ERIC Educational Resources Information Center
Hawthorn-Embree, Meredith L.; Taylor, Emily P.; Skinner, Christopher H.; Parkhurst, John; Nalls, Meagan L.
2014-01-01
After students acquire a skill, mastery often requires them to choose to engage in assigned academic activities (e.g., independent seatwork, and homework). Although students may be more likely to choose to work on partially completed assignments than on new assignments, the partial assignment completion (PAC) effect may not be very powerful. The…
Fleet Assignment Using Collective Intelligence
NASA Technical Reports Server (NTRS)
Antoine, Nicolas E.; Bieniawski, Stefan R.; Kroo, Ilan M.; Wolpert, David H.
2004-01-01
Airline fleet assignment involves the allocation of aircraft to a set of flights legs in order to meet passenger demand, while satisfying a variety of constraints. Over the course of the day, the routing of each aircraft is determined in order to minimize the number of required flights for a given fleet. The associated flow continuity and aircraft count constraints have led researchers to focus on obtaining quasi-optimal solutions, especially at larger scales. In this paper, the authors propose the application of an agent-based integer optimization algorithm to a "cold start" fleet assignment problem. Results show that the optimizer can successfully solve such highly- constrained problems (129 variables, 184 constraints).
Voltage problems on transmission networks subject to unusual power flow patterns
Ilic, M.; Stankovic, A. . Lab. for Electromagnetic and Electronic Systems)
1991-02-01
In this paper existence conditions for the physically acceptable voltage solution in power transmission networks are given and a sensitivity-based approach for their real-time evaluation is outlined. Proposed theoretical results are illustrated on a simplified Pennsylvania-Jersey-Maryland model, on which reactive power/voltage problems were reported to exist. On the same system a comparison of the most typical voltage controls is made. Different corrective control actions are compared in context of their role within multiple utility power wheeling operating mode. The paper represents an overall attempt to link existing operating voltage problems (frequently economics driven) to the theoretical results necessary for their fundamental understanding and, further, for designing efficient real time system monitoring and control techniques.
NASA Astrophysics Data System (ADS)
Motoyama, H.
1989-05-01
The present situations of superconducting electric power machines in the world and studied problems were investigated from viewpoint of the electric insulation. 50MVA generator (CRIE/Hitachi) or 120MVA generator (KWU/Siemens) where the dc superconducting technique was applied on field windings, are developed. As to Superconducting transformer, 220KVA transformer is trially manufactured and the conceptual design of 1,000MVA transformer is made by W.H. or Alstom. Future problems are the study of protecting method for the overvoltage to superconducting electric power machines and the study to prevent the quench for superconducting windings. The respective insulating characteristics of solid and liquid insulators become clear gradually under the cryogenic condition but a large part of insulating characteristics of composite insulator prepared by combination of both insulators are not clear, so that these problems must be clarified.
Cubic Icosahedra? A Problem in Assigning Symmetry
ERIC Educational Resources Information Center
Lloyd, D. R.
2010-01-01
There is a standard convention that the icosahedral groups are classified separately from the cubic groups, but these two symmetry types have been conflated as "cubic" in some chemistry textbooks. In this note, the connection between cubic and icosahedral symmetries is examined, using a simple pictorial model. It is shown that octahedral and…
Typical applications of a microcomputer database manager to power system problems
Rao, N.D.
1987-08-01
This paper reports on the application of a popular DBMS (database management system) to the solution of selected problems in Power Systems with the IBM Personal Computer in the context of the Power Engineering Curriculum at the University of Calgary. The problems selected are inductance and capacitance calculations of overhead transmission lines and per unit calculations for large power networks. These examples illustrate how to structure, organize, manipulate and query a database and also use it to service one or more independent application program modules to perform specific tasks without unnecessary data duplication. The power and flexibility of command file programming involving multiple database file access as well as program demodulation are also shown. The application programs developed in the paper amply demonstrate not only the benefits of the built-in query language, but also the ability of the DBMS to interface these programs with one or several database files. Because of these versatile features, microcomputer database management systems hold considerable promise as important, cost effective supplementary tools to conventional programming for power utilities as well.
Optimal processor assignment for pipeline computations
NASA Technical Reports Server (NTRS)
Nicol, David M.; Simha, Rahul; Choudhury, Alok N.; Narahari, Bhagirath
1991-01-01
The availability of large scale multitasked parallel architectures introduces the following processor assignment problem for pipelined computations. Given a set of tasks and their precedence constraints, along with their experimentally determined individual responses times for different processor sizes, find an assignment of processor to tasks. Two objectives are of interest: minimal response given a throughput requirement, and maximal throughput given a response time requirement. These assignment problems differ considerably from the classical mapping problem in which several tasks share a processor; instead, it is assumed that a large number of processors are to be assigned to a relatively small number of tasks. Efficient assignment algorithms were developed for different classes of task structures. For a p processor system and a series parallel precedence graph with n constituent tasks, an O(np2) algorithm is provided that finds the optimal assignment for the response time optimization problem; it was found that the assignment optimizing the constrained throughput in O(np2log p) time. Special cases of linear, independent, and tree graphs are also considered.
Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Koga, J.; Kondo, K.; Korn, G.
2015-01-15
The ways toward modeling of astrophysical processes and extreme field regimes with super-power lasers are discussed. The main attention is paid to the problem of limited similarity in using the dimensionless parameters characterizing the processes in the laser and astrophysical plasmas. As the most typical examples, we address the magnetic reconnection and collisionless shock waves relevant to the problem of ultrarelativistic particle acceleration. In the extreme field limits we consider the regimes of dominant radiation reaction, changing the electromagnetic wave-matter interaction. In these regimes it, in particular, results in a new powerful source of ultra high-brightness gamma-rays and will make possible electron-positron pair creation in vacuum in a multiphoton processes. This will allow modeling under terrestrial laboratory conditions the processes in astrophysical objects and paves the way to experimental verifications using ultra intense lasers as they are currently developed within the ELI project.
Solution of the N-body problem with recurrent power series.
NASA Technical Reports Server (NTRS)
Broucke, R.
1971-01-01
Adaptation of Steffensen's method of solution of both the restricted and general three-body problems in terms of power series in time to the solution of the equations of motion of N planets around the sun. The key feature of this adaptation lies in the introduction of N new variables and in the use of new relations which contain the time derivatives and can thus be treated as differential equations.
ERIC Educational Resources Information Center
Post, Robert E.; Johnson, Jack E.
1982-01-01
Presents two assignments that show (1) how George Orwell's "Politics and the English Language" can be applied to business writing and (2) how structured student-teacher conferences can generate enthusiasm for oral expression in a business communication course. (AEA)
Nova-Scotia Power's Point Aconi plant overcomes CFB design problems to become rock of reliability
Peltier, R.
2006-09-15
Point Aconi's circulating fluidized-bed boiler experienced erosion, corrosion, and fouling problems from the day it went on-line in 1993. After several frustrating years of unreliable operation, in late 1999, Nova Scotia Power discovered the right combination of engineering and fuel modifications. Today, after a switch to 80% petroleum coke and major boiler modifications, Point Aconi's output exceeds its original nameplate rating. For having the vision and fortitude to plan and execute a multi year, $20 million project to revitalize North America's first in-service utility CFB boiler, Nova Scotia Power's Point Aconi plant is the well-deserved winner of POWER magazine's 2006 Marmaduke Award for excellence in O & M. The award is named for Marmaduke Surfaceblow, the fictional marine engineer/plant troubleshooter par excellence. 10 figs. 1 tab.
NASA Technical Reports Server (NTRS)
Colston, B. W.
1986-01-01
Various issues associated with getting technology development of nuclear power systems moving at a pace which will support the anticipated need for such systems in later years is discussed. The projected power needs of such advanced space elements as growth space stations and lunar and planetary vehicles and bases are addressed briefly, and the relevance of nuclear power systems is discussed. A brief history and status of the U.S. nuclear reactor systems is provided, and some of the problems (real and/or perceived) are dealt with briefly. Key areas on which development attention should be focused in the near future are identified, and a suggested approach is recommended to help accelerate the process.
Farfan, E.
2009-09-30
Decommissioning of nuclear power plants and other nuclear fuel cycle facilities has been an imperative issue lately. There exist significant experience and generally accepted recommendations on remediation of lands with residual radioactive contamination; however, there are hardly any such recommendations on remediation of cooling ponds that, in most cases, are fairly large water reservoirs. The literature only describes remediation of minor reservoirs containing radioactive silt (a complete closure followed by preservation) or small water reservoirs resulting in reestablishing natural water flows. Problems associated with remediation of river reservoirs resulting in flooding of vast agricultural areas also have been described. In addition, the severity of environmental and economic problems related to the remedial activities is shown to exceed any potential benefits of these activities. One of the large, highly contaminated water reservoirs that require either remediation or closure is Karachay Lake near the MAYAK Production Association in the Chelyabinsk Region of Russia where liquid radioactive waste had been deep well injected for a long period of time. Backfilling of Karachay Lake is currently in progress. It should be noted that secondary environmental problems associated with its closure are considered to be of less importance since sustaining Karachay Lake would have presented a much higher radiological risk. Another well-known highly contaminated water reservoir is the Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond, decommissioning of which is planned for the near future. This study summarizes the environmental problems associated with the ChNPP Cooling Pond decommissioning.
Farfan, E. B.; Jannik, G. T.; Marra, J. C.; Oskolkov, B. Ya.; Bondarkov, M. D.; Gaschak, S. P.; Maksymenko, A. M.; Maksymenko, V. M.; Martynenko, V. I.
2009-11-09
Decommissioning of nuclear power plants and other nuclear fuel cycle facilities has been an imperative issue lately. There exist significant experience and generally accepted recommendations on remediation of lands with residual radioactive contamination; however, there are hardly any such recommendations on remediation of cooling ponds that, in most cases, are fairly large water reservoirs. The literature only describes remediation of minor reservoirs containing radioactive silt (a complete closure followed by preservation) or small water reservoirs resulting in reestablishing natural water flows. Problems associated with remediation of river reservoirs resulting in flooding of vast agricultural areas also have been described. In addition, the severity of environmental and economic problems related to the remedial activities is shown to exceed any potential benefits of these activities. One of the large, highly contaminated water reservoirs that require either remediation or closure is Karachay Lake near the MAYAK Production Association in the Chelyabinsk Region of Russia where liquid radioactive waste had been deep well injected for a long period of time. Backfilling of Karachay Lake is currently in progress. It should be noted that secondary environmental problems associated with its closure are considered to be of less importance since sustaining Karachay Lake would have presented a much higher radiological risk. Another well-known highly contaminated water reservoir is the Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond, decommissioning of which is planned for the near future. This study summarizes the environmental problems associated with the ChNPP Cooling Pond decommissioning.
Trends and problems in development of the power plants electrical part
NASA Astrophysics Data System (ADS)
Gusev, Yu. P.
2015-03-01
The article discusses some problems relating to development of the electrical part of modern nuclear and thermal power plants, which are stemming from the use of new process and electrical equipment, such as gas turbine units, power converters, and intellectual microprocessor devices in relay protection and automated control systems. It is pointed out that the failure rates of electrical equipment at Russian and foreign power plants tend to increase. The ongoing power plant technical refitting and innovative development processes generate the need to significantly widen the scope of research works on the electrical part of power plants and rendering scientific support to works on putting in use innovative equipment. It is indicated that one of main factors causing the growth of electrical equipment failures is that some of components of this equipment have insufficiently compatible dynamic characteristics. This, in turn may be due to lack or obsolescence of regulatory documents specifying the requirements for design solutions and operation of electric power equipment that incorporates electronic and microprocessor control and protection devices. It is proposed to restore the system of developing new and updating existing departmental regulatory technical documents that existed in the 1970s, one of the fundamental principles of which was placing long-term responsibility on higher schools and leading design institutions for rendering scientific-technical support to innovative development of components and systems forming the electrical part of power plants. This will make it possible to achieve lower failure rates of electrical equipment and to steadily improve the competitiveness of the Russian electric power industry and energy efficiency of generating companies.
42 CFR 433.146 - Rights assigned; assignment method.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 4 2010-10-01 2010-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... Assignment of Rights to Benefits § 433.146 Rights assigned; assignment method. (a) Except as specified...
NASA Astrophysics Data System (ADS)
Mahmoudi, Reza; Hafezalkotob, Ashkan; Makui, Ahmad
2014-06-01
Pollution and environmental protection in the present century are extremely significant global problems. Power plants as the largest pollution emitting industry have been the cause of a great deal of scientific researches. The fuel or source type used to generate electricity by the power plants plays an important role in the amount of pollution produced. Governments should take visible actions to promote green fuel. These actions are often called the governmental financial interventions that include legislations such as green subsidiaries and taxes. In this paper, by considering the government role in the competition of two power plants, we propose a game theoretical model that will help the government to determine the optimal taxes and subsidies. The numerical examples demonstrate how government could intervene in a competitive market of electricity to achieve the environmental objectives and how power plants maximize their utilities in each energy source. The results also reveal that the government's taxes and subsidiaries effectively influence the selected fuel types of power plants in the competitive market.
Reinforcement learning versus model predictive control: a comparison on a power system problem.
Ernst, Damien; Glavic, Mevludin; Capitanescu, Florin; Wehenkel, Louis
2009-04-01
This paper compares reinforcement learning (RL) with model predictive control (MPC) in a unified framework and reports experimental results of their application to the synthesis of a controller for a nonlinear and deterministic electrical power oscillations damping problem. Both families of methods are based on the formulation of the control problem as a discrete-time optimal control problem. The considered MPC approach exploits an analytical model of the system dynamics and cost function and computes open-loop policies by applying an interior-point solver to a minimization problem in which the system dynamics are represented by equality constraints. The considered RL approach infers in a model-free way closed-loop policies from a set of system trajectories and instantaneous cost values by solving a sequence of batch-mode supervised learning problems. The results obtained provide insight into the pros and cons of the two approaches and show that RL may certainly be competitive with MPC even in contexts where a good deterministic system model is available. PMID:19095542
Mehra, R.K.
1994-12-31
To optimize VAR sources on a power system, system planners must identify the location, size, and type of all available reactive power devices. The Control Design Challenge problem is to determine the least-costly VAR expansion pattern that will enable large power system to maintain acceptable voltage levels in all conditions.
47 CFR 90.267 - Assignment and use of frequencies in the 450-470 MHz band for low power use.
Code of Federal Regulations, 2014 CFR
2014-10-01
... frequency pair (watts) Operational Fixed or Base 20 6 Mobile 6 6 Portable 2 2 (ii) The maximum antenna... this chapter; (ii) For any operational fixed, base or mobile station exceeding the low power or antenna... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Standards...
47 CFR 90.267 - Assignment and use of frequencies in the 450-470 MHz band for low power use.
Code of Federal Regulations, 2010 CFR
2010-10-01
... frequency pair (watts) Operational Fixed or Base 20 6 Mobile 6 6 Portable 2 2 (ii) The maximum antenna... this chapter; (ii) For any operational fixed, base or mobile station exceeding the low power or antenna... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Standards...
47 CFR 90.267 - Assignment and use of frequencies in the 450-470 MHz band for low power use.
Code of Federal Regulations, 2012 CFR
2012-10-01
... frequency pair (watts) Operational Fixed or Base 20 6 Mobile 6 6 Portable 2 2 (ii) The maximum antenna... this chapter; (ii) For any operational fixed, base or mobile station exceeding the low power or antenna... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Standards...
47 CFR 90.267 - Assignment and use of frequencies in the 450-470 MHz band for low power use.
Code of Federal Regulations, 2013 CFR
2013-10-01
... frequency pair (watts) Operational Fixed or Base 20 6 Mobile 6 6 Portable 2 2 (ii) The maximum antenna... this chapter; (ii) For any operational fixed, base or mobile station exceeding the low power or antenna... COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Standards...
Generalised Assignment Matrix Methodology in Linear Programming
ERIC Educational Resources Information Center
Jerome, Lawrence
2012-01-01
Discrete Mathematics instructors and students have long been struggling with various labelling and scanning algorithms for solving many important problems. This paper shows how to solve a wide variety of Discrete Mathematics and OR problems using assignment matrices and linear programming, specifically using Excel Solvers although the same…
Model Refinement Using Eigensystem Assignment
NASA Technical Reports Server (NTRS)
Maghami, Peiman G.
2000-01-01
IA novel approach for the refinement of finite-element-based analytical models of flexible structures is presented. The proposed approach models the possible refinements in the mass, damping, and stiffness matrices of the finite element model in the form of a constant gain feedback with acceleration, velocity, and displacement measurements, respectively. Once the free elements of the structural matrices have been defined, the problem of model refinement reduces to obtaining position, velocity, and acceleration gain matrices with appropriate sparsity that reassign a desired subset of the eigenvalues of the model, along with partial mode shapes, from their baseline values to those obtained from system identification test data. A sequential procedure is used to assign one conjugate pair of eigenvalues at each step using symmetric output feedback gain matrices, and the eigenvectors are partially assigned, while ensuring that the eigenvalues assigned in the previous steps are not disturbed. The procedure can also impose that gain matrices be dissipative to guarantee the stability of the refined model. A numerical example, involving finite element model refinement for a structural testbed at NASA Langley Research Center (Controls-Structures-Interaction Evolutionary model) is presented to demonstrate the feasibility of the proposed approach.
NASA Astrophysics Data System (ADS)
Mikhaylov, V. E.; Khomenok, L. A.; Sherapov, V. V.
2016-08-01
The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.
Target assignment of simultaneous arrival for UAVs
NASA Astrophysics Data System (ADS)
Xia, Jie; Gao, Jinyuan
2003-09-01
The Extend Hungary Method (EHM) is presented to solve the assignment problem that the number of UAVs is larger than that of targets. The target assignment is modeling and the motivations are minimize the distance of the UAV fleet, maximize the survivability of the UAV fleet, maximize the number of UAVs assigned to each target and maximize the number of target attacked. An algorithm for arriving simultaneously is presented by combination of the EHM. Simulation results demonstrating the feasibility of the approach are presented. The approach could be easily applied into other multi-robot cooperative mission.
NASA Astrophysics Data System (ADS)
Damyanova, M.; Sabchevski, S.; Zhelyazkov, I.; Vasileva, E.; Balabanova, E.; Dankov, P.; Malinov, P.
2016-05-01
Powerful gyrotrons are necessary as sources of strong microwaves for electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) of magnetically confined plasmas in various reactors (most notably ITER) for controlled thermonuclear fusion. Adequate physical models and efficient problem-oriented software packages are essential tools for numerical studies, analysis, optimization and computer-aided design (CAD) of such high-performance gyrotrons operating in a CW mode and delivering output power of the order of 1-2 MW. In this report we present the current status of our simulation tools (physical models, numerical codes, pre- and post-processing programs, etc.) as well as the computational infrastructure on which they are being developed, maintained and executed.
Learning through Writing: Teaching Critical Thinking Skills in Writing Assignments
ERIC Educational Resources Information Center
Cavdar, Gamze; Doe, Sue
2012-01-01
Traditional writing assignments often fall short in addressing problems in college students' writing as too often these assignments fail to help students develop critical thinking skills and comprehension of course content. This article reports the use of a two-part (staged) writing assignment with postscript as a strategy for improving critical…
ERIC Educational Resources Information Center
Hebert, Margaret; And Others
1991-01-01
Contains seven brief articles which offer assignments designed to help students perform job searches, write job application letters, answer difficult questions, write letters of resignation, alleviate fears of public speaking, use the interview effectively in the business communication, and develop listening skills. (PRA)
Principals Make Assignments Matter
ERIC Educational Resources Information Center
Dougherty, Eleanor
2013-01-01
The inner-city high school in Washington, DC, that Guillaume Gendre joined as an assistant principal had a modest reputation for achievement but was nevertheless challenged to raise expectations for student work. In other schools, Gendre had used assignments--a specific kind of instructional task in which students are charged to think about an…
Solving Man-Induced Large-Scale Conservation Problems: The Spanish Imperial Eagle and Power Lines
López-López, Pascual; Ferrer, Miguel; Madero, Agustín; Casado, Eva; McGrady, Michael
2011-01-01
Background Man-induced mortality of birds caused by electrocution with poorly-designed pylons and power lines has been reported to be an important mortality factor that could become a major cause of population decline of one of the world rarest raptors, the Spanish imperial eagle (Aquila adalberti). Consequently it has resulted in an increasing awareness of this problem amongst land managers and the public at large, as well as increased research into the distribution of electrocution events and likely mitigation measures. Methodology/Principal Findings We provide information of how mitigation measures implemented on a regional level under the conservation program of the Spanish imperial eagle have resulted in a positive shift of demographic trends in Spain. A 35 years temporal data set (1974–2009) on mortality of Spanish imperial eagle was recorded, including population censuses, and data on electrocution and non-electrocution of birds. Additional information was obtained from 32 radio-tracked young eagles and specific field surveys. Data were divided into two periods, before and after the approval of a regional regulation of power line design in 1990 which established mandatory rules aimed at minimizing or eliminating the negative impacts of power lines facilities on avian populations. Our results show how population size and the average annual percentage of population change have increased between the two periods, whereas the number of electrocuted birds has been reduced in spite of the continuous growing of the wiring network. Conclusions Our results demonstrate that solving bird electrocution is an affordable problem if political interest is shown and financial investment is made. The combination of an adequate spatial planning with a sustainable development of human infrastructures will contribute positively to the conservation of the Spanish imperial eagle and may underpin population growth and range expansion, with positive side effects on other endangered
NASA Astrophysics Data System (ADS)
Sun, Cong; Yang, Yunchuan; Yuan, Yaxiang
2012-12-01
In this article, we investigate the interference alignment (IA) solution for a K-user MIMO interference channel. Proper users' precoders and decoders are designed through a desired signal power maximization model with IA conditions as constraints, which forms a complex matrix optimization problem. We propose two low complexity algorithms, both of which apply the Courant penalty function technique to combine the leakage interference and the desired signal power together as the new objective function. The first proposed algorithm is the modified alternating minimization algorithm (MAMA), where each subproblem has closed-form solution with an eigenvalue decomposition. To further reduce algorithm complexity, we propose a hybrid algorithm which consists of two parts. As the first part, the algorithm iterates with Householder transformation to preserve the orthogonality of precoders and decoders. In each iteration, the matrix optimization problem is considered in a sequence of 2D subspaces, which leads to one dimensional optimization subproblems. From any initial point, this algorithm obtains precoders and decoders with low leakage interference in short time. In the second part, to exploit the advantage of MAMA, it continues to iterate to perfectly align the interference from the output point of the first part. Analysis shows that in one iteration generally both proposed two algorithms have lower computational complexity than the existed maximum signal power (MSP) algorithm, and the hybrid algorithm enjoys lower complexity than MAMA. Simulations reveal that both proposed algorithms achieve similar performances as the MSP algorithm with less executing time, and show better performances than the existed alternating minimization algorithm in terms of sum rate. Besides, from the view of convergence rate, simulation results show that the MAMA enjoys fastest speed with respect to a certain sum rate value, while hybrid algorithm converges fastest to eliminate interference.
Robust transient stabilisation problem for a synchronous generator in a power network
NASA Astrophysics Data System (ADS)
Verrelli, C. M.; Damm, G.
2010-04-01
The robust transient stabilisation problem (with stability proof) of a synchronous generator in an uncertain power network with transfer conductances is rigorously formulated and solved. The generator angular speed and electrical power are required to be kept close, when mechanical and electrical perturbations occur, to the synchronous speed and mechanical input power, respectively, while the generator terminal voltage is to be regulated, when perturbations are removed, to its pre-fault reference constant value. A robust adaptive nonlinear feedback control algorithm is designed on the basis of a third-order model of the synchronous machine: only two system parameters (synchronous machine damping and inertia constants) along with upper and lower bounds on the remaining uncertain ones are supposed to be known. The conditions to be satisfied by the remote network dynamics for guaranteeing ℒ2 and ℒ∞ robustness and asymptotic relative speed and voltage regulation to zero are weaker than those required by the single machine-infinite bus approximation: dynamic interactions between the local deviations of the generator states from the corresponding equilibrium values and the remote generators states are allowed.
Gain weighted eigenspace assignment
NASA Technical Reports Server (NTRS)
Davidson, John B.; Andrisani, Dominick, II
1994-01-01
This report presents the development of the gain weighted eigenspace assignment methodology. This provides a designer with a systematic methodology for trading off eigenvector placement versus gain magnitudes, while still maintaining desired closed-loop eigenvalue locations. This is accomplished by forming a cost function composed of a scalar measure of error between desired and achievable eigenvectors and a scalar measure of gain magnitude, determining analytical expressions for the gradients, and solving for the optimal solution by numerical iteration. For this development the scalar measure of gain magnitude is chosen to be a weighted sum of the squares of all the individual elements of the feedback gain matrix. An example is presented to demonstrate the method. In this example, solutions yielding achievable eigenvectors close to the desired eigenvectors are obtained with significant reductions in gain magnitude compared to a solution obtained using a previously developed eigenspace (eigenstructure) assignment method.
The JKR-type adhesive contact problems for power-law shaped axisymmetric punches
NASA Astrophysics Data System (ADS)
Borodich, Feodor M.; Galanov, Boris A.; Suarez-Alvarez, Maria M.
2014-08-01
The JKR (Johnson, Kendall, and Roberts) and Boussinesq-Kendall models describe adhesive frictionless contact between two isotropic elastic spheres, and between a flat-ended axisymmetric punch and an elastic half-space respectively. However, the shapes of contacting solids may be more general than spherical or flat ones. In addition, the derivation of the main formulae of these models is based on the assumption that the material points within the contact region can move along the punch surface without any friction. However, it is more natural to assume that a material point that came to contact with the punch sticks to its surface, i.e. to assume that the non-slipping boundary conditions are valid. It is shown that the frictionless JKR model may be generalized to arbitrary convex, blunt axisymmetric body, in particular to the case of the punch shape being described by monomial (power-law) punches of an arbitrary degree d≥1. The JKR and Boussinesq-Kendall models are particular cases of the problems for monomial punches, when the degree of the punch d is equal to two or it goes to infinity respectively. The generalized problems for monomial punches are studied under both frictionless and non-slipping (or no-slip) boundary conditions. It is shown that regardless of the boundary conditions, the solution to the problems is reduced to the same dimensionless relations among the actual force, displacements and contact radius. The explicit expressions are derived for the values of the pull-off force and for the corresponding critical contact radius. Connections of the results obtained for problems of nanoindentation in the case of the indenter shape near the tip has some deviation from its nominal shape and the shape function can be approximated by a monomial function of radius, are discussed.
ERIC Educational Resources Information Center
Gale, David; And Others
Four units make up the contents of this document. The first examines applications of finite mathematics to business and economies. The user is expected to learn the method of optimization in optimal assignment problems. The second module presents applications of difference equations to economics and social sciences, and shows how to: 1) interpret…
NASA Astrophysics Data System (ADS)
Blaabjerg, Frede; Teodorescu, Remus; Chen, Zhe
Power electronics is an emerging technology. New applications are added every year as well as the power handling capabilities is steadily increasing. One example is renewable energy, which is efficiently enabled by power electronics. The demands to the education of engineers in this field are also increasing. Generally, the content of the curriculum should be more expanded without extra study time. This paper presents a teaching approach, which very fast makes it possible for the students to obtain in-depth skills into new research areas, and this method is the problem-oriented and project-based learning. The necessary skills for power electronic engineers are outlined that is followed up by a description on how the problem-oriented and project-based learning are implemented. A complete curriculum in power electronics and drives at Aalborg University is presented where different power electronics related projects at different study levels are finally presented.
Worldwide assessment of steam-generator problems in pressurized-water-reactor nuclear power plants
Woo, H.H.; Lu, S.C.
1981-09-15
Objective is to assess the reliability of steam generators of pressurized water reactor (PWR) power plants in the United States and abroad. The assessment is based on operation experience of both domestic and foreign PWR plants. The approach taken is to collect and review papers and reports available from the literature as well as information obtained by contacting research institutes both here and abroad. This report presents the results of the assessment. It contains a general background of PWR plant operations, plant types, and materials used in PWR plants. A review of the worldwide distribution of PWR plants is also given. The report describes in detail the degradation problems discovered in PWR steam generators: their causes, their impacts on the performance of steam generators, and the actions to mitigate and avoid them. One chapter is devoted to operating experience of PWR steam generators in foreign countries. Another discusses the improvements in future steam generator design.
Qualitative methods to solve qualitative problems in power system state estimation
Costa, A.S.; Pizza, T.S. ); Mandel, A. )
1990-08-01
A combinatorial approach to deal with qualitative problems related to power system state estimation is proposed. The discussed techniques share the same theoretical background which also underlies a previously proposed method for observability analysis. The combinatorial framework is presented and further exploited to devise a fast method for identification of single critical measurements. This method is then extended to allow the determination of critical measurement sets. The interest in investigating these questions lies in the fact that, when contaminated by gross errors, critical measurements are undetectable, whereas measurements in critical sets are unidentifiable. The performance of the proposed combinatorial methods is appraised by means of several tests, using the IEEE-14 and 30 bus systems and two realistic systems of Brazilian utilities.
Problems of applications of high power IR radiation in aquatic medium under high pressure
NASA Astrophysics Data System (ADS)
Sorokin, Yurii V.; Kuzyakov, Boris A.
2004-06-01
In this work the effects that appear in the optical breakdown are analyzed in water and the time dependences received also for the velocities and pressures at the wave fronts. The application of acoustic waves, generated by high power laser pulses in the aqueous medium, has quite serious perspectives for sounding. It is shown in the work that under comparatively low power density of radiation, as a result of a surface layer heating, the thermoelastic sresses arise, leading to the excitation of the acoustic waves. The analysis showed that the prognostic evaluations of the values of a light deflagration area are possible for a clear aqueous medium with the pressures up to 400 kg/cm2. With the presence of microinhomogeneities, it is necessary to know their total physical and chemical properties and detailed trustworthy data by their spatial distribution. A principally new approach was developed to the problem of videoinformation transmission from the object surfaces by the fiber-optic channel. The application of a precision measuring TV-camera with a color format in the range 0.3 - 0.98 μm allows to raise the information capacity of the transmitted information. The optimization of vision module choice are considered also.
Matejka, K; South, J
1989-01-01
How can you more effectively lead your group? In today's world of rapid technological and social change, where Thriving on Chaos is the best-selling management book, group work is not a luxury, but a necessity. Although some employees naturally prefer working alone, we all must function effectively in group settings. To lead a group well, the leader needs to be sensitive to three critical variables: participation, power, and problem-solving. Balancing these processes becomes the key to effective performance. The leader must pay close attention to what is happening within the group and make specific interventions to more effectively distribute the skills and energies of the members. Making every group member a significant contributor takes skill but results in more accurate decisions and greater commitment. The group leader is the facilitator, charged with managing the problem-solving process and leading the group to the most productive, objective outcome. This article supplies many practical, corrective strategies for moving your group in a more positive direction. PMID:10303698
Pathways to Assignment of Payees
Rosen, Marc I.; Ablondi, Karen; Black, Anne C.; Serowik, Kristin L.; Rowe, Michael
2013-01-01
How clients come to be assigned representative payees and/or conservators to manage their funds is not well understood. We compared clients assigned a payee during a clinical trial of a money management-based intervention to those not assigned payees and examined antecedents to payee assignment. One year after randomization, significantly more clients assigned to the ATM money management intervention were assigned payees than participants in the control condition (10 of 47 vs. 2 of 43; p=.02); those assigned payees had lower baseline GAF scores and participated more in study therapies. Several ATM clients were assigned payees after third parties paid more attention to clients’ finances, and others after having negotiated storage of their funds with the ATM money manager during the study. Assignment of payees appears to be influenced by whether third parties critically attend to how clients’ manage funds and by clients’ receptiveness to having a payee. PMID:23765182
Integrated assignment and path planning
NASA Astrophysics Data System (ADS)
Murphey, Robert A.
2005-11-01
A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact
Oskolkov, B Ya; Bondarkov, M D; Gaschak, S P; Maksymenko, A M; Maksymenko, V M; Martynenko, V I; Farfán, E B; Jannik, G T; Marra, J C
2010-11-01
Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination of their territories is an imperative issue. Significant problems may result from decommissioning of cooling ponds with residual radioactive contamination. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained water reservoirs in the Chernobyl region and Ukrainian and Belorussian Polesye region. The 1986 ChNPP Reactor Unit Number Four significantly contaminated the ChNPP Cooling Pond. The total radionuclide inventory in the ChNPP Cooling Pond bottom deposits are as follows: ¹³⁷Cs: 16.28 ± 2.59 TBq; ⁹⁰Sr: 2.4 ± 0.48 TBq; and ²³⁹+²⁴⁰Pu: 0.00518 ± 0.00148 TBq. The ChNPP Cooling Pond is inhabited by over 500 algae species and subspecies, over 200 invertebrate species, and 36 fish species. The total mass of the living organisms in the ChNPP Cooling Pond is estimated to range from about 60,000 to 100,000 tons. The territory adjacent to the ChNPP Cooling Pond attracts many birds and mammals (178 bird species and 47 mammal species were recorded in the Chernobyl Exclusion Zone). This article describes several options for the ChNPP Cooling Pond decommissioning and environmental problems associated with its decommissioning. The article also provides assessments of the existing and potential exposure doses for the shoreline biota. For the 2008 conditions, the estimated total dose rate values were 11.4 40 μGy h⁻¹ for amphibians, 6.3 μGy h⁻¹ for birds, 15.1 μGy h⁻¹ for mammals, and 10.3 μGy h⁻¹ for reptiles, with the recommended maximum dose rate being equal to 40 μGy h⁻¹. However, drying the ChNPP Cooling Pond may increase the exposure doses to 94.5 μGy h⁻¹ for amphibians, 95.2 μGy h⁻¹ for birds, 284.0 μGy h⁻¹ for mammals, and 847.0 μGy h⁻¹ for reptiles. All of these anticipated dose rates exceed the recommended values. PMID:20938234
Structural Case Assignment in Korean
ERIC Educational Resources Information Center
Koak, Heeshin
2012-01-01
In this dissertation, I aim to provide a theory on the distribution of structural Case in Korean. I propose the following Structural Case Assignment Hypothesis (SCAH) regarding the assignment of structural Case: "Structural Case is assigned by phase heads (C: nominative; v: accusative) to every argument in the c-command domain of the phase…
A graph-dynamic model of the power law of practice and the problem-solving fan-effect.
Shrager, J; Hogg, T; Huberman, B A
1988-10-21
Numerous human learning phenomena have been observed and captured by individual laws, but no unified theory of learning has succeeded in accounting for these observations. A theory and model are proposed that account for two of these phenomena: the power law of practice and the problem-solving fan-effect. The power law of practice states that the speed of performance of a task will improve as a power of the number of times that the task is performed. The power law resulting from two sorts of problem-solving changes, addition of operators to the problem-space graph and alterations in the decision procedure used to decide which operator to apply at a particular state, is empirically demonstrated. The model provides an analytic account for both of these sources of the power law. The model also predicts a problem-solving fan-effect, slowdown during practice caused by an increase in the difficulty of making useful decisions between possible paths, which is also found empirically. PMID:3175664
Fair Assignment of Responsibilities.
ERIC Educational Resources Information Center
Yeaman, Andrew R. J.
1994-01-01
Focuses on the principle of the Association of Educational Communications and Technology (AECT) Code of Professional Ethics that deals with delegating tasks only to qualified personnel who have training or can demonstrate competency in performing the task. A problem illustrating the need for the principle and a discussion of its application are…
NASA Astrophysics Data System (ADS)
Avrutsky, G. D.; Zakharov, A. E.; Sargsyan, V. A.; Frolov, M. S.; Schwartz, A. L.; Adamov, A. S.
2015-09-01
The occurrence of cracks at locations in which bottoms are welded to the high-pressure heaters' headers was revealed during planned repairs of the Perm district power plant units. Specialists of the All-Russia Thermal Engineering Institute carried out investigations aimed at obtaining more detailed data on the effect the loading cyclicity and sliding-pressure operating modes have on the reliability of power-generating equipment. Another aim of those investigations was to elaborate recommendations for achieving more reliable operation of power-generating equipment under the conditions of cyclic variation of its load. The state of the main and auxiliary equipment of the Perm district power plant units is analyzed for determining the possibility and advisability of their further operation in sliding-pressure modes. The results obtained from calculating the permissible number of load variation cycles for the headers used in the Perm district power plant units operating under the conditions of startup-shutdown modes are analyzed, and the headers' residual cyclic service life is estimated. The results obtained from a metallographic investigation of the high-pressure header's bottom in the welded joint of which a through crack was revealed are presented. Recommendations for examining the header bottoms and for modifying their design in order to improve their operational reliability are given.
Data Movement Dominates: Advanced Memory Technology to Address the Real Exascale Power Problem
Bergman, Keren
2014-08-28
Energy is the fundamental barrier to Exascale supercomputing and is dominated by the cost of moving data from one point to another, not computation. Similarly, performance is dominated by data movement, not computation. The solution to this problem requires three critical technologies: 3D integration, optical chip-to-chip communication, and a new communication model. The central goal of the Sandia led "Data Movement Dominates" project aimed to develop memory systems and new architectures based on these technologies that have the potential to lower the cost of local memory accesses by orders of magnitude and provide substantially more bandwidth. Only through these transformational advances can future systems reach the goals of Exascale computing with a manageable power budgets. The Sandia led team included co-PIs from Columbia University, Lawrence Berkeley Lab, and the University of Maryland. The Columbia effort of Data Movement Dominates focused on developing a physically accurate simulation environment and experimental verification for optically-connected memory (OCM) systems that can enable continued performance scaling through high-bandwidth capacity, energy-efficient bit-rate transparency, and time-of-flight latency. With OCM, memory device parallelism and total capacity can scale to match future high-performance computing requirements without sacrificing data-movement efficiency. When we consider systems with integrated photonics, links to memory can be seamlessly integrated with the interconnection network-in a sense, memory becomes a primary aspect of the interconnection network. At the core of the Columbia effort, toward expanding our understanding of OCM enabled computing we have created an integrated modeling and simulation environment that uniquely integrates the physical behavior of the optical layer. The PhoenxSim suite of design and software tools developed under this effort has enabled the co-design of and performance evaluation photonics-enabled OCM
ERIC Educational Resources Information Center
Gauthier, N.
2008-01-01
A general method is presented for evaluating the sums of "m"th powers of the integers that can, and that cannot, be represented in the two-element Frobenius problem. Generating functions are introduced and used for that purpose. Explicit formulas for the desired sums are obtained and specific examples are discussed.
Balanced input-output assignment
NASA Technical Reports Server (NTRS)
Gawronski, W.; Hadaegh, F. Y.
1989-01-01
Actuator/sensor locations and balanced representations of linear systems are considered for a given set of controllability and observability grammians. The case of equally controlled and observed states is given special attention. The assignability of grammians is examined, and the conditions for their existence are presented, along with several algorithms for their determination. Although an arbitrary positive semidefinite matrix is not always assignable, the identity grammian is shown to be always assignable. The results are extended to the case of flexible structures.
Tidal power development -- A realistic, justifiable and topical problem of today
Bernshtein, L.B.
1995-09-01
Modern tidal power plant designs have shown that with the use of large single-basin schemes, tidal power can be integrated with other forms of power generation. Tidal power is an environmentally benign means of producing electricity, particularly during off-peak demand. A number of tidal power schemes have been evaluated. These include Cumberland (1.4 Gigawatts (GW)), Cobequid (4.4 GW) in Canada; Sevrn (8.6 GW), Mersey (0.7 GW), Wyre (0.06 GW) and Conwy (0.03 GW) in Great Britain; Tugur (6.8 GW) in Russia and Garolim (0.5 GW) in South Korea. These schemes ar opening up future prospects for very large scale opportunities which could have global importance, for example, the transmission of 24 GW of electricity from tidal power plants in Great Britain to Europe. Another example is the potential transmission of 87 GW from Penzhinsh tidal power plant in Russia.
On Automated Grading of Programming Assignments in an Academic Institution
ERIC Educational Resources Information Center
Cheang, Brenda; Kurnia, Andy; Lim, Andrew; Oon, Wee-Chong
2003-01-01
Practise is one of the most important steps in learning the art of computer programming. Unfortunately, human grading of programming assignments is a tedious and error-prone task, a problem compounded by the large enrolments of many programming courses. As a result, students in such courses tend to be given fewer programming assignments than…
Supervising Unsuccessful Student Teaching Assignments: Two Terminator's Tales.
ERIC Educational Resources Information Center
St. Maurice, Henry
2001-01-01
Discusses problems that arise when there is a conflict between a student teacher and the supervising teacher and when a student teacher does not perform satisfactorily. Focuses on how supervisors deal with failed assignments and how beginning teachers improve their teaching and learn from failed assignments. (Contains 21 references.) (JOW)
42 CFR 433.146 - Rights assigned; assignment method.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 4 2013-10-01 2013-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS STATE FISCAL ADMINISTRATION Third Party...
42 CFR 433.146 - Rights assigned; assignment method.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 42 Public Health 4 2011-10-01 2011-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS STATE FISCAL ADMINISTRATION Third Party...
42 CFR 433.146 - Rights assigned; assignment method.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 4 2014-10-01 2014-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS STATE FISCAL ADMINISTRATION Third Party...
42 CFR 433.146 - Rights assigned; assignment method.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 4 2012-10-01 2012-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS STATE FISCAL ADMINISTRATION Third Party...
Towards Automated Structure-Based NMR Resonance Assignment
NASA Astrophysics Data System (ADS)
Jang, Richard; Gao, Xin; Li, Ming
We propose a general framework for solving the structure-based NMR backbone resonance assignment problem. The core is a novel 0-1 integer programming model that can start from a complete or partial assignment, generate multiple assignments, and model not only the assignment of spins to residues, but also pairwise dependencies consisting of pairs of spins to pairs of residues. It is still a challenge for automated resonance assignment systems to perform the assignment directly from spectra without any manual intervention. To test the feasibility of this for structure-based assignment, we integrated our system with our automated peak picking and sequence-based resonance assignment system to obtain an assignment for the protein TM1112 with 91% recall and 99% precision without manual intervention. Since using a known structure has the potential to allow one to use only N-labeled NMR data and avoid the added expense of using C-labeled data, we work towards the goal of automated structure-based assignment using only such labeled data. Our system reduced the assignment error of Xiong-Pandurangan-Bailey-Kellogg's contact replacement (CR) method, which to our knowledge is the most error-tolerant method for this problem, by 5 folds on average. By using an iterative algorithm, our system has the added capability of using the NOESY data to correct assignment errors due to errors in predicting the amino acid and secondary structure type of each spin system. On a publicly available data set for Ubiquitin, where the type prediction accuracy is 83%, we achieved 91% assignment accuracy, compared to the 59% accuracy that was obtained without correcting for typing errors.
Constrained Task Assignment and Scheduling On Networks of Arbitrary Topology
NASA Astrophysics Data System (ADS)
Jackson, Justin Patrick
This dissertation develops a framework to address centralized and distributed constrained task assignment and task scheduling problems. This framework is used to prove properties of these problems that can be exploited, develop effective solution algorithms, and to prove important properties such as correctness, completeness and optimality. The centralized task assignment and task scheduling problem treated here is expressed as a vehicle routing problem with the goal of optimizing mission time subject to mission constraints on task precedence and agent capability. The algorithm developed to solve this problem is able to coordinate vehicle (agent) timing for task completion. This class of problems is NP-hard and analytical guarantees on solution quality are often unavailable. This dissertation develops a technique for determining solution quality that can be used on a large class of problems and does not rely on traditional analytical guarantees. For distributed problems several agents must communicate to collectively solve a distributed task assignment and task scheduling problem. The distributed task assignment and task scheduling algorithms developed here allow for the optimization of constrained military missions in situations where the communication network may be incomplete and only locally known. Two problems are developed. The distributed task assignment problem incorporates communication constraints that must be satisfied; this is the Communication-Constrained Distributed Assignment Problem. A novel distributed assignment algorithm, the Stochastic Bidding Algorithm, solves this problem. The algorithm is correct, probabilistically complete, and has linear average-case time complexity. The distributed task scheduling problem addressed here is to minimize mission time subject to arbitrary predicate mission constraints; this is the Minimum-time Arbitrarily-constrained Distributed Scheduling Problem. The Optimal Distributed Non-sequential Backtracking Algorithm
Environmental Problems Associated with Decommissioning of Chernobyl Power Plant Cooling Pond
NASA Astrophysics Data System (ADS)
Foley, T. Q.; Oskolkov, B. Y.; Bondarkov, M. D.; Gashchak, S. P.; Maksymenko, A. M.; Maksymenko, V. M.; Martynenko, V. I.; Jannik, G. T.; Farfan, E. B.; Marra, J. C.
2009-12-01
Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination is a fairly pressing issue. Significant problems may result from decommissioning of cooling ponds. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained bodies of water in the Chernobyl Region and Ukrainian Polesye with a water surface area of 22.9 km2. The major hydrological feature of the ChNPP Cooling Pond is that its water level is 6-7 m higher than the water level in the Pripyat River and water losses due to seepage and evaporation are replenished by pumping water from the Pripyat River. In 1986, the accident at the ChNPP #4 Reactor Unit significantly contaminated the ChNPP Cooling Pond. According to the 2001 data, the total radionuclide inventory in the ChNPP Cooling Pond bottom deposits was as follows: 16.28 ± 2.59 TBq for 137Cs; 2.4 ± 0.48 TBq for 90Sr, and 0.00518 ± 0.00148 TBq for 239+240Pu. Since ChNPP is being decommissioned, the ChNPP Cooling Pond of such a large size will no longer be needed and cost effective to maintain. However, shutdown of the water feed to the Pond would expose the contaminated bottom deposits and change the hydrological features of the area, destabilizing the radiological and environmental situation in the entire region in 2007 - 2008, in order to assess potential consequences of draining the ChNPP Cooling Pond, the authors conducted preliminary radio-ecological studies of its shoreline ecosystems. The radioactive contamination of the ChNPP Cooling Pond shoreline is fairly variable and ranges from 75 to 7,500 kBq/m2. Three areas with different contamination levels were selected to sample soils, vegetation, small mammals, birds, amphibians, and reptilians in order to measure their 137Cs and 90Sr content. Using the ERICA software, their dose exposures were estimated. For the 2008 conditions, the estimated dose rates were found to be as follows: amphibians - 11
Belwin Edward, J; Rajasekar, N; Sathiyasekar, K; Senthilnathan, N; Sarjila, R
2013-09-01
Obtaining optimal power flow solution is a strenuous task for any power system engineer. The inclusion of FACTS devices in the power system network adds to its complexity. The dual objective of OPF with fuel cost minimization along with FACTS device location for IEEE 30 bus is considered and solved using proposed Enhanced Bacterial Foraging algorithm (EBFA). The conventional Bacterial Foraging Algorithm (BFA) has the difficulty of optimal parameter selection. Hence, in this paper, BFA is enhanced by including Nelder-Mead (NM) algorithm for better performance. A MATLAB code for EBFA is developed and the problem of optimal power flow with inclusion of FACTS devices is solved. After several run with different initial values, it is found that the inclusion of FACTS devices such as SVC and TCSC in the network reduces the generation cost along with increased voltage stability limits. It is also observed that, the proposed algorithm requires lesser computational time compared to earlier proposed algorithms. PMID:23759251
Improving load balance with flexibly assignable tasks
Pinar, Ali; Hendrickson, Bruce
2003-09-09
In many applications of parallel computing, distribution ofthe data unambiguously implies distribution of work among processors. Butthere are exceptions where some tasks can be assigned to one of severalprocessors without altering the total volume of communication. In thispaper, we study the problem of exploiting this flexibility in assignmentof tasks to improve load balance. We first model the problem in terms ofnetwork flow and use combinatorial techniques for its solution. Ourparametric search algorithms use maximum flow algorithms for probing on acandidate optimal solution value. We describe two algorithms to solve theassignment problem with \\logW_T and vbar P vbar probe calls, w here W_Tand vbar P vbar, respectively, denote the total workload and number ofproce ssors. We also define augmenting paths and cuts for this problem,and show that anyalgorithm based on augmenting paths can be used to findan optimal solution for the task assignment problem. We then consideracontinuous version of the problem, and formulate it as a linearlyconstrained optimization problem, i.e., \\min\\|Ax\\|_\\infty,\\; {\\rms.t.}\\;Bx=d. To avoid solving an intractable \\infty-norm optimization problem,we show that in this case minimizing the 2-norm is sufficient to minimizethe \\infty-norm, which reduces the problem to the well-studiedlinearly-constrained least squares problem. The continuous version of theproblem has the advantage of being easily amenable to parallelization.Our experiments with molecular dynamics and overlapped domaindecomposition applications proved the effectiveness of our methods withsignificant improvements in load balance. We also discuss how ourtechniques can be enhanced for heterogeneous systems.
76 FR 55880 - Recording Assignments
Federal Register 2010, 2011, 2012, 2013, 2014
2011-09-09
..., depending on the date they were recorded. The public may also search patent and trademark assignment... United States Patent and Trademark Office Recording Assignments ACTION: Proposed collection; comment request. SUMMARY: The United States Patent and Trademark Office (USPTO), as part of its continuing...
ERIC Educational Resources Information Center
Powell, Nicole P.; Boxmeyer, Caroline L.; Baden, Rachel; Stromeyer, Sara; Minney, Jessica A.; Mushtaq, Asia; Lochman, John E.
2011-01-01
Children with high levels of aggressive behavior and conduct problems create major management problems in school settings and interfere with the learning environment of their classmates and with their own academic achievement. A contextual social-cognitive model can provide a framework for understanding risk factors involved in the development and…
Interactive software for spectral assignment
NASA Technical Reports Server (NTRS)
Mielke, R. R.; Carraway, P. I.; Marefat, M.
1985-01-01
A new interactive computer software package for eigenvalue/eigenvector assignment using constant state feedback is described. The package consists of ten subprograms, each associated with a specific design objective, accessible from a main control program. Using this package, primary design objectives of assigning eigenvalues and approximating eigenvectors are first achieved. Then secondary design objectives, including modification of specific eigenvector components, reduction in specified elements of the feedback gain matrix, and reduction in eigensystem sensitivity to changes in plant parameters, are addressed. These secondary objectives are achieved by a systematic modification of the assigned eigenvectors in a small region about the initial assignment. In addition, the program implements the use of spectral assignment procedures with reduced-order system models. Program modes are described and illustrated by numerical examples.
NASA Astrophysics Data System (ADS)
Morris, Robert A.
1990-12-01
The emphasis is on defining a set of communicating processes for intelligent spacecraft secondary power distribution and control. The computer hardware and software implementation platform for this work is that of the ADEPTS project at the Johnson Space Center (JSC). The electrical power system design which was used as the basis for this research is that of Space Station Freedom, although the functionality of the processes defined here generalize to any permanent manned space power control application. First, the Space Station Electrical Power Subsystem (EPS) hardware to be monitored is described, followed by a set of scenarios describing typical monitor and control activity. Then, the parallel distributed problem solving approach to knowledge engineering is introduced. There follows a two-step presentation of the intelligent software design for secondary power control. The first step decomposes the problem of monitoring and control into three primary functions. Each of the primary functions is described in detail. Suggestions for refinements and embelishments in design specifications are given.
NASA Technical Reports Server (NTRS)
Morris, Robert A.
1990-01-01
The emphasis is on defining a set of communicating processes for intelligent spacecraft secondary power distribution and control. The computer hardware and software implementation platform for this work is that of the ADEPTS project at the Johnson Space Center (JSC). The electrical power system design which was used as the basis for this research is that of Space Station Freedom, although the functionality of the processes defined here generalize to any permanent manned space power control application. First, the Space Station Electrical Power Subsystem (EPS) hardware to be monitored is described, followed by a set of scenarios describing typical monitor and control activity. Then, the parallel distributed problem solving approach to knowledge engineering is introduced. There follows a two-step presentation of the intelligent software design for secondary power control. The first step decomposes the problem of monitoring and control into three primary functions. Each of the primary functions is described in detail. Suggestions for refinements and embelishments in design specifications are given.
NASA Astrophysics Data System (ADS)
Kishor, Ram
2016-07-01
We consider a generalized photogravitational Chermnykh-like problem and determine orbits in the basin of collinear equilibrium points. We suppose that bigger primary is radiating body; smaller primary is an oblate spheroid and a disk with power law density profile is rotating around the common center of mass of the system. We compute three types of orbits namely, periodic, hyperbolic and asymptotic orbit, of the infinitesimal body. Also, we analyse, effect of radiation pressure and oblateness and it is noticed that time period of the periodic orbits depends on these parameters. KEYWORDS: Chermnykh-like problem; Orbits; Radiation pressure; Oblateness; Disk; Collinear equilibrium points.
An Assignment Sequence for Underprepared Writers.
ERIC Educational Resources Information Center
Nimmo, Kristi
2000-01-01
Presents a sequenced writing assignment on shopping to aid basic writers. Describes a writing assignment focused around online and mail-order shopping. Notes steps in preparing for the assignment, the sequence, and discusses responses to the assignments. (SC)
Wind power demonstration and siting problems. [for recharging electrically driven automobiles
NASA Technical Reports Server (NTRS)
Bergey, K. H.
1973-01-01
Technical and economic feasibility studies on a small windmill to provide overnight charging for an electrically driven car are reported. The auxiliary generator provides power for heating and cooling the vehicle which runs for 25 miles on battery power alone, and for 50 miles with the onboard charger operating. The blades for this windmill have a diameter of 12 feet and are coupled through to a conventional automobile alternator so that they are able to completely recharge car batteries in 8 hours. Optimization of a windmill/storage system requires detailed wind velocity information which permits rational sitting of wind power system stations.
The UF6 Breeder - A solution to the problems of nuclear power
NASA Technical Reports Server (NTRS)
Williams, J. R.; Clement, J. D.; Rust, J. A.
1975-01-01
One of the major advantages of uranium hexafluoride reactors for power generation is the simplified fuel reprocessing scheme which the gaseous fuel makes possible. Critical experiments related to the development of the reactors for electric power generation are discussed along with UF6 breeder reactor studies. Previous energy conversion studies are reported, taking into account gas turbine power plants, thermionic conversion, and MHD conversion. Thermodynamic cycle analyses show that high efficiencies can be achieved using UF6 as the working fluid for Rankine or Brayton cycles without requiring excessive temperatures.
Exploiting Flexibly Assignable Work to Improve Load Balance
Pinar, Ali; Hendrickson, Bruce
2002-12-09
In many applications of parallel computing, distribution of the data unambiguously implies distribution of work among processors. But there are exceptions where some tasks can be assigned to one of several processors without altering the total volume of communication. In this paper, we study the problem of exploiting this flexibility in assignment of tasks to improve load balance. We first model the problem in terms of network flow and use combinatorial techniques for its solution. Our parametric search algorithms use maximum flow algorithms for probing on a candidate optimal solution value. We describe two algorithms to solve the assignment problem with log W{sub T} and |P| probe calls, where W{sub T} and |P|, respectively, denote the total workload and number of processors. We also define augmenting paths and cuts for this problem, and show that any algorithm based on augmenting paths can be used to find an optimal solution for the task assignment problem. We then consider a continuous version of the problem, and formulate it as a linearly constrained optimization problem, i.e., min ||Ax||{sub {infinity}}, s.t. Bx = d. To avoid solving an intractable {infinity}-norm optimization problem, we show that in this case minimizing the 2-norm is sufficient to minimize the {infinity}-norm, which reduces the problem to the well-studied linearly-constrained least squares problem. The continuous version of the problem has the advantage of being easily amenable to parallelization.
Node assignment in heterogeneous computing
NASA Technical Reports Server (NTRS)
Som, Sukhamoy
1993-01-01
A number of node assignment schemes, both static and dynamic, are explored for the Algorithm to Architecture Mapping Model (ATAMM). The architecture under consideration consists of heterogeneous processors and implements dataflow models of real-time applications. Terminology is developed for heterogeneous computing. New definitions are added to the ATAMM for token and assignment classifications. It is proved that a periodic execution is possible for dataflow graphs. Assignment algorithms are developed and proved. A design procedure is described for satisfying an objective function in an heterogeneous architecture. Several examples are provided for illustration.
The inhibiting bisection problem.
Pinar, Ali
2010-11-01
Given a graph where each vertex is assigned a generation or consumption volume, we try to bisect the graph so that each part has a significant generation/consumption mismatch, and the cutsize of the bisection is small. Our motivation comes from the vulnerability analysis of distribution systems such as the electric power system. We show that the constrained version of the problem, where we place either the cutsize or the mismatch significance as a constraint and optimize the other, is NP-complete, and provide an integer programming formulation. We also propose an alternative relaxed formulation, which can trade-off between the two objectives and show that the alternative formulation of the problem can be solved in polynomial time by a maximum flow solver. Our experiments with benchmark electric power systems validate the effectiveness of our methods.
Study on the Uneven cells Problem of the Power Battery Pack in the Automotive Application by ECM
NASA Astrophysics Data System (ADS)
Jiayuan, Wang; Zechang, Sun; Xuezhe, Wei; Haifeng, Dai
Uneven cells problem is a universal phenomenon in the cell grouping application. It will cause performance and safety problems if the uneven is not considered during pack design and application, especially for the automotive application. The ECM model is used for the study of the uneven cells phenomenon of the power battery pack in the automotive application. An EV model and a FCV model are used for simulating the current profiles for two representative powertrain systems. The links of the ECM are set in five conditions for separate study on the impact. The results show different impact on the SOC and voltage with the same sets of links for the two powertrain model. The cell grouping design and the balance algorithm should be adjusted according to the different application background when the uneven cells problems are considered.
ERIC Educational Resources Information Center
Kek, Megan Yih Chyn A.; Huijser, Henk
2011-01-01
This article describes problem-based learning as a powerful pedagogical approach and an aligned teaching and learning system to explicitly and directly teach critical thinking skills in a broad range of disciplines. Problem-based learning is argued to be a powerful pedagogical approach as it explicitly and actively engages students in a learning…
Sims, T.R.; Jones, R.A. . Research and Development Dept.); Imece, A.F. )
1990-09-01
Islanding is one of the major concerns that electric power utilities have about the impact of distributed photovoltaic (PV) generation. Islanding is the isolated operation of PV systems after the interruption of utility power. This paper reports the results of a research project on the possible islanding operation of a section of a distribution feeder containing line-commutated static power converters. The approach of the project was to develop a computer model of the SPC to predict islanding operation and verify the model with laboratory and field tests. The computer model accurately predicted the operation of the SPC during islanding. Furthermore, the effect of general system parameters on the islanding performance of the Gemini line-commutated SPC are presented.
Problems in developing bimodal space power and propulsion system fuel element
Nikolaev, Yu. V.; Gontar, A. S.; Zaznoba, V. A.; Parshin, N. Ya.; Ponomarev-Stepnoi, N. N.; Usov, V. A.
1997-01-10
The paper discusses design of a space nuclear power and propulsion system fuel element (PPFE) developed on the basis of an enhanced single-cell thermionic fuel element (TFE) of the 'TOPAZ-2' thermionic converter-reactor (TCR), and presents the PPFE performance for propulsion and power modes of operation. The choice of UC-TaC fuel composition is substantiated. Data on hydrogen effect on the PPFE output voltage are presented, design solutions are considered that allow to restrict hydrogen supply to an interelectrode gap (IEG). Long-term geometric stability of an emitter assembly is supported by calculated data.
Optimum frequency assignment for satellite SCPC systems
NASA Astrophysics Data System (ADS)
Okinaka, H.; Yasuda, Y.; Hirata, Y.
A technique for deriving a quasi-optimum solution for IM-minimum channel allocation for single-level SCPC systems is presented. Two types of IM products are considered as the dominant components in an RF band. The third order IM product is proportional to the product of the power of concerned carriers, allowing a weighting function to be defined for calculating the IM noise. An IM minimum channel allocation technique can then be used to reduce the IM noise occurring in the carrier slots through frequency assignment. The worst carrier is automatically deleted with an initial channel allocation and the process is iterated until the maximum noise reduction is obtained. The first two or three carriers are assigned to unused frequency slots with low noise. The method is also viable when dealing with a larger number of carriers.
New Electric Power Technologies: Problems and Prospects for the 1990s.
ERIC Educational Resources Information Center
Congress of the U.S., Washington, DC. Office of Technology Assessment.
This report responds to a request from the House Committee on Science and Technology and its Subcommittee on Energy Development and Applications to analyze a range of new electric power generating, storage, and load management technologies. The Office of Technology Assessment (OTA) examined these technologies in terms of their current and expected…
ERIC Educational Resources Information Center
Beauvais, Clementine
2013-01-01
This article takes as its starting point the concept of aetonormativity (the adult normativity germane to the discourse of children's literature), coined by Maria Nikolajeva (2010) in an attempt to unify the increasingly power-oriented theories of children's literature criticism within the past few decades. Acknowledging the usefulness of this…
Photoelastic analysis in respect to failure mechanics problems of power plant articles and units
NASA Astrophysics Data System (ADS)
Korikhin, N. V.; Eigenson, S. N.
2009-02-01
The results of strength tests of some critical articles and units of power plants, i.e., a reactor vessel, threaded connection of vessel split, pressure header with straight nipple, turbomachine shaft, and T-weld joint of stator and rotor parts, of turbomachines are presented.
The "Culture Problem" in Intercultural Communication: Toward a Critical Proficiency of Power
ERIC Educational Resources Information Center
Chen, Eunju Chung
2013-01-01
Intercultural Communication (INCC) is dominated by a simple conception of culture that has, in essence, led its research and literature away from attending to relations of power in intercultural relationships. INCC's traditional approach based on positivistic and static notions of culture are rather anemic in their own right but also too brittle…
ERIC Educational Resources Information Center
Craddock, Alan E.
1980-01-01
Married Australian couples possessing heterogeneous values involving religious principles and family relationship v vocational priorities were disadvantaged when solving problems for which such values were relevant. Data indicated that effects of dyad authority role expectations and value patterns were modified upon interaction by sex and…
Systems approach to walk-off problems for dish-type solar thermal power systems
NASA Technical Reports Server (NTRS)
Jaffe, L. D.; Levin, R. R.; Moynihan, P. I.; Nesmith, B. J.; Owen, W. A.; Roschke, E. J.; Starkey, D. J.; Thostesen, T. O.
1983-01-01
'Walk-off' in a dish-type solar thermal power system is a failure situation in which the concentrator remains fixed while the spot of concentrated sunlight slowly moves across the face of the receiver. The intense local heating may damage the receiver and nearby equipment. Passive protection has advantages in minimizing damage, but in a fully passive design the receiver must be able to withstand full solar input with no forced fluid circulation during the walk-off. An active walk-off emergency subsystem may include an emergency detrack or defocus mechanism or sun-blocking device, emergency power, sensors and logic to detect the emergency and initiate protective action, and cooling or passive protection of emergency and non-emergency components. Each of these elements is discussed and evaluated in the paper.
Role of electrical problems in the failure of Narora power plant
Rao, J.S.
1995-12-31
In the early morning hours on March 31, 1993, a major accident took place in a nuclear power plant located at Narora in Northern India. A huge fire with bright yellow-red flame was seen at both ends of the generator. Extensive damage to the power and control cables and bus ducts took place during this accident. The vertical aluminum ducting above the neutral transformer was completely melted. The ducts ending near the excitation panels had been shattered. All the panels of AVR, Field Breaker and thyristor cubicles were completely damaged in the fire. Mechanical failures include fatigue fracture of Blade No. 52 of the last stage, Bearings No. 4 and No. 5, Generator seals. This paper describes the role of electrical systems in this accident.
[Some problems in measuring the frequency-resolving power of hearing].
Supin, A Ia
2004-08-01
In spite of detailed elaboration of masking methods of measuring the frequency selectivity of hearing, such measurements actually are not in use for diagnostics purpose because of their time-consumption and ambiguity of extrapolation of the results to perception of complex sound spectrum patterns. A method of direct measuring of spectrum resolving power using rippled-noise test, is suggested. Results of measurements have shown that the actual ability of hearing to discriminate complex sound spectra is higher than that predicted by acuteness of auditory frequency filters: dependence of acuteness of auditory frequency filters on sound level does not influence the ability to discriminate complex spectra; and the influence on interfering noise on the frequency resolving power can not be explained by a decrease of the spectral contrast by the spread of excitation. PMID:15552366
Systems approach to walk-off problems for dish-type solar thermal power systems
NASA Astrophysics Data System (ADS)
Jaffe, L. D.; Levin, R. R.; Moynihan, P. I.; Nesmith, B. J.; Owen, W. A.; Roschke, E. J.; Starkey, D. J.; Thostesen, T. O.
'Walk-off' in a dish-type solar thermal power system is a failure situation in which the concentrator remains fixed while the spot of concentrated sunlight slowly moves across the face of the receiver. The intense local heating may damage the receiver and nearby equipment. Passive protection has advantages in minimizing damage, but in a fully passive design the receiver must be able to withstand full solar input with no forced fluid circulation during the walk-off. An active walk-off emergency subsystem may include an emergency detrack or defocus mechanism or sun-blocking device, emergency power, sensors and logic to detect the emergency and initiate protective action, and cooling or passive protection of emergency and non-emergency components. Each of these elements is discussed and evaluated in the paper.
NASA Technical Reports Server (NTRS)
Bromley, L. K.; Travis, A. D.
1980-01-01
The compatibility and performance of the Shuttle communications system must be certified prior to operational missions. For this purpose, NASA has established the Electronics Systems Test Laboratory (ESTL) at the Johnson Space Center. This paper discusses the Shuttle communications system compatibility and performance testing being performed in the ESTL. The ESTL system verification test philosophy, including capabilities, procedures, and unique testing equipment are summarized. Summaries of the significant results of compatibility and performance tests of the Orbiter/Space-flight Tracking and Data Network, Orbiter/Air Force Remote Tracking Station, Orbiter/Tracking and Data Relay Satellite System and Orbiter/Shuttle Launch Support System interfaces are presented. The ESTL's unique ability to locate potential communication problems and participate in the resolution of these problems are discussed in detail.
[Hygienic problems in the location of modern wind electric power stations in their design].
Kireeva, I S; Makhniuk, V M; Akimenko, V Ia; Dumanskiĭ, Iu D; Semashko, P V
2013-01-01
Hygienic aspects of the placement of wind power plants (WPP) in connection with the intensive development of wind power and the lack of systematic information on their effects of the environment and living conditions of the population are becoming more actual. In the article there are considered results of the sanitary-epidemiological expertise of the construction project of three modern large wind farm (the South - Ukrainian, Tiligulskaya and Pokrovskaya) with a total capacity offrom 180 to 500 MW of wind farms with 2.3 MW power generators of wind turbines. It is shown that in the process of wind farm construction a contamination of the environment (air soil, ground water) may take place due to the working of construction equipment and vehicle, excavation, welding and other operations, in the exploitation of wind farm there can be created elevated levels of acoustic and electromagnetic pollution in the neighborhood and emergencies with the destruction of WPP in adverse weather conditions. Based on the calculations presented in the projects, and the analysis of data on the impact offoreign windfarm on the environment it was found that the limiting factor of the influence is the wind farm noise pollution in the audio frequency range that extends beyond the territory of wind fields, electromagnetic radiation is recorded within the hygienic standards and below only in the immediate vicinity of its sources (electrical equipment and power lines). For considered modern wind farms there was grounded sanitary protective zone with dimensions of 700 mfrom the outermost wind turbines by the noise and it was recommended compliance distance of200 mfrom the wind turbine to limit any activity and people staying in times of possible emergency situations in adverse weather conditions. PMID:24624820
NASA Astrophysics Data System (ADS)
Baryshnikov, Fedor F.
1995-10-01
The influence of angular aberration of radiation as a result of the difference in speed of a geostationary satellite and the speed of the Earth's surface on laser power beaming to satellites is considered. Angular aberration makes it impossible to direct the energy to the satellite, and additional beam rotation is necessary. Because the Earth's rotation may cause how to transfer incoherent radiation to remote satellites. In the framework of the Kolmogorov turbulence model simple conditions of energy transfer are derived and discussed.
Assigning functional meaning to digital circuits
Eckmann, S.T.; Chisholm, G.H.
1997-07-01
During computer-aided design, the problem of how to determine the logical function of a digital circuit arises in many contexts. For example, assigning functional meaning to a circuit is a fundamental operation in both reverse engineering and implementation validation. This report describes such a determination by discussing how a higher-level functional representation is constructed from a detailed circuit description (i.e., a gate-level netlist, which is a list of logic gates and their interconnections). The approach used involves transforming parts of the netlist into a functional representation and then manipulating this representation. Two types of functional representations are described: (1) a mathematical representation based on the logical operators ``exor`` and ``and`` and (2) a directed acyclic graph representation based on binary decision trees. Each representation provides a canonical form of the logical function being implemented (i.e., a form that is independent of implementation details). Such forms, however, have a well-known problem associated with the ordering of inputs: for each order, a unique form exists. A solution to this problem is given for both representations. Experimental results that demonstrate the use of these representations in the process of assigning functional meaning to a circuit are provided. The report also identifies and discusses issues critical to the performance required of this fundamental operation.
A Stochastic Employment Problem
ERIC Educational Resources Information Center
Wu, Teng
2013-01-01
The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…
Expert systems for personnel assignment
Hardee, J.L.; Liepins, G.
1986-01-01
In order to reduce stress on assignment personnel (detailers) and ensure maximum fairness and consistency in the Navy's personnel assignment process, The Navy Military Personnel Command (NMPC) has begun to explore the potential use of expert systems to supplement current manual and computerized distribution methods. The Detailer's Assistant expert system is being developed to improve the detailers' ability to satisfy the needs of their constituents and Navy management. An initial prototype of the Detailer's Assistant is now being evaluated. Numerous upgrades and extensions should lead to an operational system in the near future. Further development to a production system will involve additional research in machine learning, intelligent database methods, and cooperating expert systems.
RBS/ERD simulation problems: Stopping powers, nuclear reactions and detector resolution
NASA Astrophysics Data System (ADS)
Ziegler, J. F.
1998-03-01
A new program has been developed for the graphical analysis of data from Rutherford Back scattering (RBS) and Elastic Recoil Detection (ERD) material analysis experiments. The program can evaluate experiments using any incident ion, at any energy, for any planar target. It incorporates the full stopping power database of the SRIM/TRIM ion beam programs. All scattered ions and recoiling target atoms are followed out of the target and through any filtering absorbers (ERD absorber foils and foils on detector windows). Straggling is included using any of five optional straggling theories. Commonly used nuclear reaction cross-sections are automatically incorporated. By comparison with experimental data, weaknesses in the theoretical basis of RBS/ERD simulations become apparent. These will be discussed with emphasis on stopping powers, detector resolution, target setup and nuclear reaction cross-sections. The complete RBS/ERD software package can be downloaded from the web site: http://www.research.ibm.com/ionbeams. This package includes an installation manual and a full tutorial.
ERIC Educational Resources Information Center
Murphy, Pat, Ed.
1993-01-01
"Exploring" is a magazine of science, art, and human perception, produced by Exploratorium in collaboration with other participating museums. This issue focuses on puzzles and problem solving. Brain teasers, puzzles, and the strategies for solving them are included. Features include: (1) "Homework Assignment #3" (Paul Doherty); (2) "The Case of…
Mercury emissions and coal-fired power plants: Understanding the problems and identifying solutions
Davis, S.E.
1997-12-31
Electric utility emissions contribute to an array of air quality concerns, most notably ground-level ozone, acid deposition, global warming, and fine particulate pollution. More recently, electric utility emissions of air toxics such as mercury have been linked to serious ecological health effects, especially in fish-eating birds. Another issue that is gaining attention is that of eutrophication in marine waters from nitrogen oxide emissions. Coal-fired power plants warrant special consideration, particularly in regards to mercury. Coal-fired power plants currently represent over 30% of controllable anthropogenic emissions in the US and are expected to emit nearly half of all anthropogenic emissions in the US by 2010. However, because the human health threshold for mercury is not known with certainty and mercury control technologies such as activated carbon injection are extremely expensive, mercury emissions from electric utilities have not been addressed in the US through either regulation or voluntary initiatives. The Center is beginning to evaluate the viability of no- or low-regrets measures that may be more consistent with the current state of the science on human and ecological health effects. The Center is also looking at options to reduce eutophication. Specifically, the Center has: hosted a workshop to assess the viability of low-cost mercury control options for electric utilities, developed a proposal to undertake a mercury banking initiative, worked to reduce compliance costs associated with multiple and conflicting regulations, and investigated the potential benefits and workability of NOx trading between air and water sources These activities are described in greater detail in the Center`s paper.
Assertiveness for Librarians Harried by Inappropriate Lecture Hall and Classroom Assignments.
ERIC Educational Resources Information Center
Parker, J. Carlyle
1990-01-01
Describes problems encountered by public librarians when assisting students with assignments that are difficult or impossible to complete. Examples of librarians' successes in assertive, tactful communication with instructors and a list of solutions to inappropriate assignments are provided. Special emphasis is given to assignments dealing with…
Some remarks on assignment maps
NASA Astrophysics Data System (ADS)
Masillo, F.; Scolarici, G.; Solombrino, L.
2011-01-01
We study the properties of general linear assignment maps, showing that positivity axiom can be suitably relaxed, and propose a new class of dynamical maps (generalized dynamics). A puzzling result, arising in such a context in quantum information theory, is also discussed.
"Pique": A Group Dictionary Assignment.
ERIC Educational Resources Information Center
Smith, Jane Bowman
1983-01-01
THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: This exercise replaces the standard, often boring introductory lecture on using the dictionary with a group assignment that encourages the students to observe and analyze the entry for at least one word very carefully. In doing so, the students discover for themselves both the kinds of information…
Who Benefits from Homework Assignments?
ERIC Educational Resources Information Center
Ronning, Marte
2011-01-01
Using Dutch data on pupils in elementary school this paper is the first empirical study to analyze whether assigning homework has a heterogeneous impact on pupil achievement. Addressing potential biases by using a difference-in-difference approach, I find that the test score gap is larger in classes where everybody gets homework than in classes…
Managing Large Volumes of Assignments
ERIC Educational Resources Information Center
Park, James; Hagen, John, Jr.
2005-01-01
In spring 2003, the Distance Education Network (DEN), Viterbi School of Engineering at the University of Southern California (USC), had 860 students and more than 1,000 enrollments in 70 courses toward 10 different degrees. Typically, for assignments in engineering courses, professors require students to show how their answers are derived so that…
Wang, Zhong Lin
2014-01-01
Triboelectrification is one of the most common effects in our daily life, but it is usually taken as a negative effect with very limited positive applications. Here, we invented a triboelectric nanogenerator (TENG) based on organic materials that is used to convert mechanical energy into electricity. The TENG is based on the conjunction of triboelectrification and electrostatic induction, and it utilizes the most common materials available in our daily life, such as papers, fabrics, PTFE, PDMS, Al, PVC etc. In this short review, we first introduce the four most fundamental modes of TENG, based on which a range of applications have been demonstrated. The area power density reaches 1200 W m(-2), volume density reaches 490 kW m(-3), and an energy conversion efficiency of ∼50-85% has been demonstrated. The TENG can be applied to harvest all kinds of mechanical energy that is available in our daily life, such as human motion, walking, vibration, mechanical triggering, rotation energy, wind, a moving automobile, flowing water, rain drops, tide and ocean waves. Therefore, it is a new paradigm for energy harvesting. Furthermore, TENG can be a sensor that directly converts a mechanical triggering into a self-generated electric signal for detection of motion, vibration, mechanical stimuli, physical touching, and biological movement. After a summary of TENG for micro-scale energy harvesting, mega-scale energy harvesting, and self-powered systems, we will present a set of questions that need to be discussed and explored for applications of the TENG. Lastly, since the energy conversion efficiencies for each mode can be different although the materials are the same, depending on the triggering conditions and design geometry. But one common factor that determines the performance of all the TENGs is the charge density on the two surfaces, the saturation value of which may independent of the triggering configurations of the TENG. Therefore, the triboelectric charge density or the
NASA Astrophysics Data System (ADS)
Bezrukovs, Valerijs; Bezrukovs, Vladislavs; Levins, Nikolajs
2011-01-01
Interest in the use of renewable energy in Latvia is increasing every year. Government support and availability of large unpopulated areas on the coast makes the use of these lands for the placement of large wind power plants (WPP) attractive. The key factors that determine the choice of the location of WPP are reliable information about distribution of the resource of wind energy in this area and the influence of wind turbines on the environment. The paper presents the results of years-long observations on the density fluctuations of wind energy at heights of
Toward a powerful problem-based training tool for harnessing lessons learned
May, W. E.; Richards, R. E.
2006-07-01
One of the purposes of this paper is to describe a training method and supporting technologies (tool) to increase personnel awareness of error precursors. This model-centered method may be an effective 'part task training' to precede more expensive fall-blown multimedia scenarios (behavioral simulations). The training is designed to efficiently increase positive transfer from lessons learned case studies. The tool enables developers to take actual instances and inexpensively frame them within an interactive computer learning environment. The learning is engaging and helps model the kind of causal thinking needed to prevent future occurrences. This method and tool could help workers 'see' the problems and feel the need to take action when they are in real settings. Another purpose of this paper is to present the results of research into the process of designing and developing this training software. The benefits for attendees are insights that may enable more rapid proto-typing of software for training the workforce. The authors will present the models, methodologies, and patterns in the participants' design activities. Results show that participants used a cyclical, spiral process that revisited design topics until they were clarified. (authors)
Integrated Project Scheduling and Staff Assignment with Controllable Processing Times
Framinan, Jose M.
2014-01-01
This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times. PMID:24895672
Neural Mechanisms of Credit Assignment in a Multicue Environment
Kolling, Nils; Brown, Joshua W.; Rushworth, Matthew
2016-01-01
In complex environments, many potential cues can guide a decision or be assigned responsibility for the outcome of the decision. We know little, however, about how humans and animals select relevant information sources that should guide behavior. We show that subjects solve this relevance selection and credit assignment problem by selecting one cue and its association with a particular outcome as the main focus of a hypothesis. To do this, we examined learning while using a task design that allowed us to estimate the focus of each subject's hypotheses on a trial-by-trial basis. When a prediction is confirmed by the outcome, then credit for the outcome is assigned to that cue rather than an alternative. Activity in medial frontal cortex is associated with the assignment of credit to the cue that is the main focus of the hypothesis. However, when the outcome disconfirms a prediction, the focus shifts between cues, and the credit for the outcome is assigned to an alternative cue. This process of reselection for credit assignment to an alternative cue is associated with lateral orbitofrontal cortex. SIGNIFICANCE STATEMENT Learners should infer which features of environments are predictive of significant events, such as rewards. This “credit assignment” problem is particularly challenging when any of several cues might be predictive. We show that human subjects solve the credit assignment problem by implicitly “hypothesizing” which cue is relevant for predicting subsequent outcomes, and then credit is assigned according to this hypothesis. This process is associated with a distinctive pattern of activity in a part of medial frontal cortex. By contrast, when unexpected outcomes occur, hypotheses are redirected toward alternative cues, and this process is associated with activity in lateral orbitofrontal cortex. PMID:26818500