Stochastic Unit Commitment via Progressive Hedging - Extensive Analysis of Solution Methods
DEFF Research Database (Denmark)
Ordoudis, Christos; Pinson, Pierre; Zugno, Marco
2015-01-01
Owing to the massive deployment of renewable power production units over the last couple of decades, the use of stochastic optimization methods to solve the unit commitment problem has gained increasing attention. Solving stochastic unit commitment problems in large-scale power systems requires h...
International Nuclear Information System (INIS)
Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas
2016-01-01
The uncertainties of renewable energy have brought great challenges to power system commitment, dispatches and reserve requirement. This paper presents a comparative study on integration of renewable generation uncertainties into SCUC (stochastic security-constrained unit commitment) considering reserve and risk. Renewable forecast uncertainties are captured by a list of PIs (prediction intervals). A new scenario generation method is proposed to generate scenarios from these PIs. Different system uncertainties are considered as scenarios in the stochastic SCUC problem formulation. Two comparative simulations with single (E1: wind only) and multiple sources of uncertainty (E2: load, wind, solar and generation outages) are investigated. Five deterministic and four stochastic case studies are performed. Different generation costs, reserve strategies and associated risks are compared under various scenarios. Demonstrated results indicate the overall costs of E2 is lower than E1 due to penetration of solar power and the associated risk in deterministic cases of E2 is higher than E1. It implies the superimposed effect of uncertainties during uncertainty integration. The results also demonstrate that power systems run a higher level of risk during peak load hours, and that stochastic models are more robust than deterministic ones. - Highlights: • An extensive comparative study for renewable integration is presented. • A novel scenario generation method is proposed. • Wind and solar uncertainties are represented by a list of prediction intervals. • Unit commitment and dispatch costs are discussed considering reserve and risk.
Energy Technology Data Exchange (ETDEWEB)
Constantinescu, E. M.; Zavala, V. M.; Rocklin, M.; Lee, S.; Anitescu, M. (Mathematics and Computer Science); (Univ. of Chicago); (New York Univ.)
2009-10-09
We present a computational framework for integrating the state-of-the-art Weather Research and Forecasting (WRF) model in stochastic unit commitment/energy dispatch formulations that account for wind power uncertainty. We first enhance the WRF model with adjoint sensitivity analysis capabilities and a sampling technique implemented in a distributed-memory parallel computing architecture. We use these capabilities through an ensemble approach to model the uncertainty of the forecast errors. The wind power realizations are exploited through a closed-loop stochastic unit commitment/energy dispatch formulation. We discuss computational issues arising in the implementation of the framework. In addition, we validate the framework using real wind speed data obtained from a set of meteorological stations. We also build a simulated power system to demonstrate the developments.
Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas
2015-09-01
Penetration of renewable energy resources, such as wind and solar power, into power systems significantly increases the uncertainties on system operation, stability, and reliability in smart grids. In this paper, the nonparametric neural network-based prediction intervals (PIs) are implemented for forecast uncertainty quantification. Instead of a single level PI, wind power forecast uncertainties are represented in a list of PIs. These PIs are then decomposed into quantiles of wind power. A new scenario generation method is proposed to handle wind power forecast uncertainties. For each hour, an empirical cumulative distribution function (ECDF) is fitted to these quantile points. The Monte Carlo simulation method is used to generate scenarios from the ECDF. Then the wind power scenarios are incorporated into a stochastic security-constrained unit commitment (SCUC) model. The heuristic genetic algorithm is utilized to solve the stochastic SCUC problem. Five deterministic and four stochastic case studies incorporated with interval forecasts of wind power are implemented. The results of these cases are presented and discussed together. Generation costs, and the scheduled and real-time economic dispatch reserves of different unit commitment strategies are compared. The experimental results show that the stochastic model is more robust than deterministic ones and, thus, decreases the risk in system operations of smart grids.
Directory of Open Access Journals (Sweden)
Heba-Allah I. ElAzab
2018-05-01
Full Text Available This paper presents a trustworthy unit commitment study to schedule both Renewable Energy Resources (RERs with conventional power plants to potentially decarbonize the electrical network. The study has employed a system with three IEEE thermal (coal-fired power plants as dispatchable distributed generators, one wind plant, one solar plant as stochastic distributed generators, and Plug-in Electric Vehicles (PEVs which can work either loads or generators based on their charging schedule. This paper investigates the unit commitment scheduling objective to minimize the Combined Economic Emission Dispatch (CEED. To reduce combined emission costs, integrating more renewable energy resources (RER and PEVs, there is an essential need to decarbonize the existing system. Decarbonizing the system means reducing the percentage of CO2 emissions. The uncertain behavior of wind and solar energies causes imbalance penalty costs. PEVs are proposed to overcome the intermittent nature of wind and solar energies. It is important to optimally integrate and schedule stochastic resources including the wind and solar energies, and PEVs charge and discharge processes with dispatched resources; the three IEEE thermal (coal-fired power plants. The Water Cycle Optimization Algorithm (WCOA is an efficient and intelligent meta-heuristic technique employed to solve the economically emission dispatch problem for both scheduling dispatchable and stochastic resources. The goal of this study is to obtain the solution for unit commitment to minimize the combined cost function including CO2 emission costs applying the Water Cycle Optimization Algorithm (WCOA. To validate the WCOA technique, the results are compared with the results obtained from applying the Dynamic Programming (DP algorithm, which is considered as a conventional numerical technique, and with the Genetic Algorithm (GA as a meta-heuristic technique.
International Nuclear Information System (INIS)
Wang, Bo; Wang, Shuming; Zhou, Xianzhong; Watada, Junzo
2016-01-01
Recent years have witnessed the ever increasing renewable penetration in power generation systems, which entails modern unit commitment problems with modelling and computation burdens. This study aims to simulate the impacts of manifold uncertainties on system operation with emission concerns. First, probability theory and fuzzy set theory are applied to jointly represent the uncertainties such as wind generation, load fluctuation and unit outage that interleaved in unit commitment problems. Second, a Value-at-Risk-based multi-objective approach is developed as a bridge of existing stochastic and robust unit commitment optimizations, which not only captures the inherent conflict between operation cost and supply reliability, but also provides easy-to-adjust robustness against worst-case scenarios. Third, a multi-objective algorithm that integrates fuzzy simulation and particle swarm optimization is developed to achieve approximate Pareto-optimal solutions. The research effectiveness is exemplified by two case studies: The comparison between test systems with and without generation uncertainty demonstrates that this study is practicable and can suggest operational insights of generation mix systems. The sensitivity analysis on Value-at-Risk proves that our method can achieve adequate tradeoff between performance optimality and robustness, thus help system operators in making informed decisions. Finally, the model and algorithm comparisons also justify the superiority of this research. - Highlights: • Probability theory and fuzzy set theory are used to describe different uncertainties. • A Value-at-Risk-based multi-objective unit commitment model is proposed. • An improved multi-objective particle swarm optimization algorithm is developed. • The model achieves adequate trade-off between performance optimality and robustness. • The algorithm can obtain convergent and diversified Pareto fronts.
Stochastic Unit Commitment Based on Multi-Scenario Tree Method Considering Uncertainty
Directory of Open Access Journals (Sweden)
Kyu-Hyung Jo
2018-03-01
Full Text Available With the increasing penetration of renewable energy, it is difficult to schedule unit commitment (UC in a power system because of the uncertainty associated with various factors. In this paper, a new solution procedure based on a multi-scenario tree method (MSTM is presented and applied to the proposed stochastic UC problem. In this process, the initial input data of load and wind power are modeled as different levels using the mean absolute percentage error (MAPE. The load and wind scenarios are generated using Monte Carlo simulation (MCS that considers forecasting errors. These multiple scenarios are applied in the MSTM for solving the stochastic UC problem, including not only the load and wind power uncertainties, but also sudden outages of the thermal unit. When the UC problem has been formulated, the simulation is conducted for 24-h period by using the short-term UC model, and the operating costs and additional reserve requirements are thus obtained. The effectiveness of the proposed solution approach is demonstrated through a case study based on a modified IEEE-118 bus test system.
DEFF Research Database (Denmark)
Vahedipour-Dahraie, Mostafa; Najafi, Hamid Reza; Anvari-Moghaddam, Amjad
2018-01-01
In this paper, a stochastic model for scheduling of AC security‐constrained unit commitment associated with demand response (DR) actions is developed in an islanded residential microgrid. The proposed model maximizes the expected profit of microgrid operator and minimizes the total customers...
An Efficient Robust Solution to the Two-Stage Stochastic Unit Commitment Problem
DEFF Research Database (Denmark)
Blanco, Ignacio; Morales González, Juan Miguel
2017-01-01
This paper proposes a reformulation of the scenario-based two-stage unitcommitment problem under uncertainty that allows finding unit-commitment plansthat perform reasonably well both in expectation and for the worst caserealization of the uncertainties. The proposed reformulation is based onpart...
Directory of Open Access Journals (Sweden)
Jiafu Yin
2018-02-01
Full Text Available With the increasing penetration of wind power and demand response integrated into the grid, the combined uncertainties from wind power and demand response have been a challenging concern for system operators. It is necessary to develop an approach to accommodate the combined uncertainties in the source side and load side. In this paper, the fuzzy stochastic conditional value-at-risk criterions are proposed as the risk measure of the combination of both wind power uncertainty and demand response uncertainty. To improve the computational tractability without sacrificing the accuracy, the fuzzy stochastic chance-constrained goal programming is proposed to transfer the fuzzy stochastic conditional value-at-risk to a deterministic equivalent. The operational risk of forecast error under fuzzy stochastic conditional value-at-risk assessment is represented by the shortage of reserve resource, which can be further divided into the load-shedding risk and the wind curtailment risk. To identify different priority levels for the different objective functions, the three-stage day-ahead unit commitment model is proposed through preemptive goal programming, in which the reliability requirement has the priority over the economic operation. Finally, a case simulation is performed on the IEEE 39-bus system to verify the effectiveness and efficiency of the proposed model.
Energy Technology Data Exchange (ETDEWEB)
Ela, E.; O' Malley, M.
2012-06-01
Variable renewable generation resources are increasing their penetration on electric power grids. These resources have weather-driven fuel sources that vary on different time scales and are difficult to predict in advance. These characteristics create challenges for system operators managing the load balance on different timescales. Research is looking into new operational techniques and strategies that show great promise on facilitating greater integration of variable resources. Stochastic Security-Constrained Unit Commitment models are one strategy that has been discussed in literature and shows great benefit. However, it is rarely used outside the research community due to its computational limits and difficulties integrating with electricity markets. This paper discusses how it can be integrated into day-ahead energy markets and especially on what pricing schemes should be used to ensure an efficient and fair market.
International Nuclear Information System (INIS)
Nikzad, Mehdi; Mozafari, Babak; Bashirvand, Mahdi; Solaymani, Soodabeh; Ranjbar, Ali Mohamad
2012-01-01
Recently in electricity markets, a massive focus has been made on setting up opportunities for participating demand side. Such opportunities, also known as demand response (DR) options, are triggered by either a grid reliability problem or high electricity prices. Two important challenges that market operators are facing are appropriate designing and reasonable pricing of DR options. In this paper, time-of-use program (TOU) as a prevalent time-varying program is modeled linearly based on own and cross elasticity definition. In order to decide on TOU rates, a stochastic model is proposed in which the optimum TOU rates are determined based on grid reliability index set by the operator. Expected Load Not Supplied (ELNS) is used to evaluate reliability of the power system in each hour. The proposed stochastic model is formulated as a two-stage stochastic mixed-integer linear programming (SMILP) problem and solved using CPLEX solver. The validity of the method is tested over the IEEE 24-bus test system. In this regard, the impact of the proposed pricing method on system load profile; operational costs and required capacity of up- and down-spinning reserve as well as improvement of load factor is demonstrated. Also the sensitivity of the results to elasticity coefficients is investigated. -- Highlights: ► Time-of-use demand response program is linearly modeled. ► A stochastic model is proposed to determine the optimum TOU rates based on ELNS index set by the operator. ► The model is formulated as a short-term two-stage stochastic mixed-integer linear programming problem.
Unit Commitment for Systems With Significant Wind Penetration
DEFF Research Database (Denmark)
Tuohy, Aidan; Meibom, Peter; Denny, E.
2009-01-01
The stochastic nature of wind alters the unit commitment and dispatch problem. By accounting for this uncertainty when scheduling the system, more robust schedules are produced, which should, on average, reduce expected costs. In this paper, the effects of stochastic wind and load on the unit...... commitment and dispatch of power systems with high levels of wind power are examined. By comparing the costs, planned operation and performance of the schedules produced, it is shown that stochastic optimization results in less costly, of the order of 0.25%, and better performing schedules than deterministic...... optimization. The impact of planning the system more frequently to account for updated wind and load forecasts is then examined. More frequent planning means more up to date forecasts are used, which reduces the need for reserve and increases performance of the schedules. It is shown that mid-merit and peaking...
Hidden power system inflexibilities imposed by traditional unit commitment formulations
International Nuclear Information System (INIS)
Morales-España, Germán; Ramírez-Elizondo, Laura; Hobbs, Benjamin F.
2017-01-01
Highlights: • Quality and accuracy of traditional-energy- and power-based UCs are evaluated. • Real-time performance evaluation simulating “perfect” stochastic UCs. • Ideal energy-based stochastic UC formulations impose hidden system inflexibilities. • A deterministic power-based UC may outperform an ideal energy-based stochastic UC. • Power-based UC overcomes flaws of energy-based UC: lower cost and wind curtailment. - Abstract: Approximations made in traditional day-ahead unit commitment model formulations can result in suboptimal or even infeasible schedules for slow-start units and inaccurate predictions of actual costs and wind curtailment. With increasing wind penetration, these errors will become economically more significant. Here, we consider inaccuracies from three approximations: the use of hourly intervals in which energy production from each generator is modeled as being constant; the disregarding of startup and shutdown energy trajectories; and optimization based on expected wind profiles. The results of unit commitment formulations with those assumptions are compared to models that: (1) use a piecewise-linear power profiles of generation, load and wind, instead of the traditional stepwise energy profiles; (2) consider startup/shutdown trajectories; and (3) include many possible wind trajectories in a stochastic framework. The day-ahead hourly schedules of slow-start generators are then evaluated against actual wind and load profiles using a model real-time dispatch and quick-start unit commitment with a 5 min time step. We find that each simplification usually causes expected generation costs to increase by several percentage points, and results in significant understatement of expected wind curtailment and, in some cases, load interruptions. The inclusion of startup and shutdown trajectories often yielded the largest improvements in schedule performance.
Fuzzy Array Approach to Unit Commitment
DEFF Research Database (Denmark)
Jantzen, Jan; Eliasson, Bo
1996-01-01
The paper investigates the unit commitment problem of Swedish power company Sydkraft as a constraint satisfaction problem. The power system is a simplified system with nuclear, thermal, and hydro generators as well as power interchange. In this paper we focus on soft constraints, for instance...
Transcriptional regulation of lineage commitment--a stochastic model of cell fate decisions.
Directory of Open Access Journals (Sweden)
Jose Teles
Full Text Available Molecular mechanisms employed by individual multipotent cells at the point of lineage commitment remain largely uncharacterized. Current paradigms span from instructive to noise-driven mechanisms. Of considerable interest is also whether commitment involves a limited set of genes or the entire transcriptional program, and to what extent gene expression configures multiple trajectories into commitment. Importantly, the transient nature of the commitment transition confounds the experimental capture of committing cells. We develop a computational framework that simulates stochastic commitment events, and affords mechanistic exploration of the fate transition. We use a combined modeling approach guided by gene expression classifier methods that infers a time-series of stochastic commitment events from experimental growth characteristics and gene expression profiling of individual hematopoietic cells captured immediately before and after commitment. We define putative regulators of commitment and probabilistic rules of transition through machine learning methods, and employ clustering and correlation analyses to interrogate gene regulatory interactions in multipotent cells. Against this background, we develop a Monte Carlo time-series stochastic model of transcription where the parameters governing promoter status, mRNA production and mRNA decay in multipotent cells are fitted to experimental static gene expression distributions. Monte Carlo time is converted to physical time using cell culture kinetic data. Probability of commitment in time is a function of gene expression as defined by a logistic regression model obtained from experimental single-cell expression data. Our approach should be applicable to similar differentiating systems where single cell data is available. Within our system, we identify robust model solutions for the multipotent population within physiologically reasonable values and explore model predictions with regard to
Energy Technology Data Exchange (ETDEWEB)
Franca, Thiago de Paula; Luciano, Edson Jose Rezende; Nepomuceno, Leonardo [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Dept. de Engenharia Eletrica], Emails: ra611191@feb.unesp.br, edson.joserl@uol.com.br, leo@feb.unesp.br
2009-07-01
A model of Unit Commitment to hydrothermal systems that includes the costs of start/stop of generators is proposed. These costs has been neglected in a good part of the programming models for operation of hydrothermal systems (pre-dispatch). The impact of the representation of costs in total production costs is evaluated. The proposed model is solved by a hybrid methodology, which involves the use of genetic algorithms (to solve the entire part of the problem) and sequential quadratic programming methods. This methodology is applied to the solution of an IEEE test system. The results emphasize the importance of representation of the start/stop in the generation schedule.
Solving unit commitment and economic load dispatch problems ...
African Journals Online (AJOL)
Economic Load Dispatch (ELD) and Unit Commitment (UC) are very important applications to predict the optimized cost of load in a power system. UC determines working states for existing generating units under some operational constraints and then optimizing the operation cost for all running units w.r.t. load demand ...
Network-constrained AC unit commitment under uncertainty: A Benders' decomposition approach
DEFF Research Database (Denmark)
Nasri, Amin; Kazempour, Seyyedjalal; Conejo, Antonio J.
2015-01-01
. The proposed model is formulated as a two-stage stochastic programming problem, whose first-stage refers to the day-ahead market, and whose second-stage represents real-time operation. The proposed Benders’ approach allows decomposing the original problem, which is mixed-integer nonlinear and generally...... intractable, into a mixed-integer linear master problem and a set of nonlinear, but continuous subproblems, one per scenario. In addition, to temporally decompose the proposed ac unit commitment problem, a heuristic technique is used to relax the inter-temporal ramping constraints of the generating units...
Unit Commitment With Dynamic Cycling Costs
Troy, Niamh; Flynn, Damian; Milligan, Michael R.; et al.
2012-01-01
Increased competition in the electricity sector and the integration of variable renewable energy sources is resulting in more frequent cycling of thermal plant. Thus, the wear-and-tear to generator components and the related costs are a growing concern for plant owners and system operators alike. This paper presents a formulation that can be implemented in a MIP dispatch model to dynamically model cycling costs based on unit operation. When implemented for a test system, the results show that...
Unit commitment with probabilistic reserve: An IPSO approach
International Nuclear Information System (INIS)
Lee, Tsung-Ying; Chen, Chun-Lung
2007-01-01
This paper presents a new algorithm for solution of the nonlinear optimal scheduling problem. This algorithm is named the iteration particle swarm optimization (IPSO). A new index, called iteration best, is incorporated into particle swarm optimization (PSO) to improve the solution quality and computation efficiency. IPSO is applied to solve the unit commitment with probabilistic reserve problem of a power system. The outage cost as well as fuel cost of thermal units was considered in the unit commitment program to evaluate the level of spinning reserve. The optimal scheduling of on line generation units was reached while minimizing the sum of fuel cost and outage cost. A 48 unit power system was used as a numerical example to test the new algorithm. The optimal scheduling of on line generation units could be reached in the testing results while satisfying the requirement of the objective function
Research on unit commitment with large-scale wind power connected power system
Jiao, Ran; Zhang, Baoqun; Chi, Zhongjun; Gong, Cheng; Ma, Longfei; Yang, Bing
2017-01-01
Large-scale integration of wind power generators into power grid brings severe challenges to power system economic dispatch due to its stochastic volatility. Unit commitment including wind farm is analyzed from the two parts of modeling and solving methods. The structures and characteristics can be summarized after classification has been done according to different objective function and constraints. Finally, the issues to be solved and possible directions of research and development in the future are discussed, which can adapt to the requirements of the electricity market, energy-saving power generation dispatching and smart grid, even providing reference for research and practice of researchers and workers in this field.
Thunderstorm Algorithm for Determining Unit Commitment in Power System Operation
Directory of Open Access Journals (Sweden)
Arif Nur Afandi
2016-12-01
Full Text Available Solving the unit commitment problem is an important task in power system operation for deciding a balanced power production between various types of generating units under technical constraints and environmental limitations. This paper presents a new intelligent computation method, called the Thunderstorm Algorithm (TA, for searching the optimal solution of the integrated economic and emission dispatch (IEED problem as the operational assessment for determining unit commitment. A simulation using the IEEE-62 bus system showed that TA has smooth convergence and is applicable for solving the IEED problem. The IEED’s solution is associated with the total fuel consumption and pollutant emission. The proposed TA method seems to be a viable new approach for finding the optimal solution of the IEED problem.
A Stochastic Unit Commitment Model for a Local CHP Plant
DEFF Research Database (Denmark)
Ravn, Hans V.; Riisom, Jannik; Schaumburg-Müller, Camilla
2005-01-01
Local CHP development in Denmark has during the 90’s been characterised by large growth primarily due to government subsidies in the form of feed-in tariffs. In line with the liberalisation process in the EU, Danish local CHPs of a certain size must operate on market terms from 2005. This paper...
Neural networks as a tool for unit commitment
DEFF Research Database (Denmark)
Rønne-Hansen, Peter; Rønne-Hansen, Jan
1991-01-01
Some of the fundamental problems when solving the power system unit commitment problem by means of neural networks have been attacked. It has been demonstrated for a small example that neural networks might be a viable alternative. Some of the major problems solved in this initiating phase form...... a basis for the analysis of real life sized problems. These will be investigated in the near future...
Improved Genetic Algorithm-Based Unit Commitment Considering Uncertainty Integration Method
Directory of Open Access Journals (Sweden)
Kyu-Hyung Jo
2018-05-01
Full Text Available In light of the dissemination of renewable energy connected to the power grid, it has become necessary to consider the uncertainty in the generation of renewable energy as a unit commitment (UC problem. A methodology for solving the UC problem is presented by considering various uncertainties, which are assumed to have a normal distribution, by using a Monte Carlo simulation. Based on the constructed scenarios for load, wind, solar, and generator outages, a combination of scenarios is found that meets the reserve requirement to secure the power balance of the power grid. In those scenarios, the uncertainty integration method (UIM identifies the best combination by minimizing the additional reserve requirements caused by the uncertainty of power sources. An integration process for uncertainties is formulated for stochastic unit commitment (SUC problems and optimized by the improved genetic algorithm (IGA. The IGA is composed of five procedures and finds the optimal combination of unit status at the scheduled time, based on the determined source data. According to the number of unit systems, the IGA demonstrates better performance than the other optimization methods by applying reserve repairing and an approximation process. To account for the result of the proposed method, various UC strategies are tested with a modified 24-h UC test system and compared.
Dataset for case studies of hydropower unit commitment
Directory of Open Access Journals (Sweden)
Jinwen Wang
2018-06-01
Full Text Available This paper presents the data all needed for nine case studies of hydropower unit commitment, which determines the optimal operating zones and generating discharges of units after the quarter-hourly releases and water heads are derived by the operation of cascaded hydropower reservoirs. The power output function and feasible operating zones of units are provided, and optimization solvers are used to acquire the results in detail for the case studies, including the quarter-hourly generating discharges, power generations, as well as operating zones of individual units. Performance indices, including the spillage, energy production, and the low-efficiency generating rate, are summarized for all case studies and can be readily used for comparison between algorithms in future.
UNIT COMMITMENT: A NEW TRUNCATED METHOD OF UNIT ...
African Journals Online (AJOL)
NIJOTECH
Data obtained from the National Electric Power Authority (NEPA) has been used to test the efficacy of this approach. ... every unit in the system must be respected. Some of these ..... Analysis of Power System Reliability. 2.Edwin K. W, Machat, ...
Multi-area unit commitment with ramp-rate limits
International Nuclear Information System (INIS)
Wang, C.; Shahidehpour, S.M.
1992-01-01
This paper reports that there are two tasks considered in power system generation scheduling. One is the unit commitment which determines the unit start up and shut down schedules in order to minimize the system fuel expenditure. The other is the economic dispatch which assigns the system load demand to the committed generating units for minimizing the power generation cost. The economic operation attracts a great deal of attention as a modest reduction in percentage fuel cost leads to a large saving in the system operation costs. Many studies for power system generation scheduling have successfully applied various mathematical algorithms such as Lagrangian relaxation, dynamic programming, and artificial intelligence techniques e.g., expert systems, artificial neural networks (ANN), etc. The AI techniques have incorporated the system practical operational policies in the mathematical techniques to improve system models considerably. The mechanism of ANN simulates the learning process of the human brain. One class of ANN learns the knowledge through examples, or training facts, composed by various inputs and their corresponding outputs. The extent of the intelligibility of ANN depends upon the diversity of the training facts. For an input which is not in the training facts, the trained ANN can estimate an output based on its previous knowledge about the problem
Symmetry Breaking in MILP Formulations for Unit Commitment Problems
Lima, Ricardo
2015-12-11
This paper addresses the study of symmetry in Unit Commitment (UC) problems solved by Mixed Integer Linear Programming (MILP) formulations, and using Linear Programming based Branch & Bound MILP solvers. We propose three sets of symmetry breaking constraints for UC MILP formulations exhibiting symmetry, and its impact on three UC MILP models are studied. The case studies involve the solution of 24 instances by three widely used models in the literature, with and without symmetry breaking constraints. The results show that problems that could not be solved to optimality within hours can be solved with a relatively small computational burden if the symmetry breaking constraints are assumed. The proposed symmetry breaking constraints are also compared with the symmetry breaking methods included in two MILP solvers, and the symmetry breaking constraints derived in this work have a distinct advantage over the methods in the MILP solvers.
Symmetry Breaking in MILP Formulations for Unit Commitment Problems
Lima, Ricardo; Novais, Augusto Q.
2015-01-01
This paper addresses the study of symmetry in Unit Commitment (UC) problems solved by Mixed Integer Linear Programming (MILP) formulations, and using Linear Programming based Branch & Bound MILP solvers. We propose three sets of symmetry breaking constraints for UC MILP formulations exhibiting symmetry, and its impact on three UC MILP models are studied. The case studies involve the solution of 24 instances by three widely used models in the literature, with and without symmetry breaking constraints. The results show that problems that could not be solved to optimality within hours can be solved with a relatively small computational burden if the symmetry breaking constraints are assumed. The proposed symmetry breaking constraints are also compared with the symmetry breaking methods included in two MILP solvers, and the symmetry breaking constraints derived in this work have a distinct advantage over the methods in the MILP solvers.
Pereira, Isabel; Veloso, Ana; Silva, Isabel Soares; Costa, Patricio
2017-05-18
This study explored the relationship between organizational commitment and job satisfaction among workers in family health units. Six family health units in the North of Portugal participated, including 105 health professionals (physicians, nurses, and clinical secretaries). The study used the Portuguese adaptations of the Organizational Commitment Scale by Meyer & Allen (1997) and the Job Satisfaction Survey (Spector, 1985). The results suggest a positive association between organizational commitment and job satisfaction. The professionals are moderately satisfied and committed to the family health units; the most satisfactory aspects are the nature of the work, relationship to coworkers, and communication, while pay is the most unsatisfactory. The affective component of the commitment appears, highlighting the professionals' involvement in (and identification with) the family health units project. The linear regression model proved significant, and organizational commitment explains 22.7% of the variance in job satisfaction. For this sample, organizational commitment predicts job satisfaction.
Integrating generation and transmission networks reliability for unit commitment solution
International Nuclear Information System (INIS)
Jalilzadeh, S.; Shayeghi, H.; Hadadian, H.
2009-01-01
This paper presents a new method with integration of generation and transmission networks reliability for the solution of unit commitment (UC) problem. In fact, in order to have a more accurate assessment of system reserve requirement, in addition to unavailability of generation units, unavailability of transmission lines are also taken into account. In this way, evaluation of the required spinning reserve (SR) capacity is performed by applying reliability constraints based on loss of load probability and expected energy not supplied (EENS) indices. Calculation of the above parameters is accomplished by employing a novel procedure based on the linear programming which it also minimizes them to achieve optimum level of the SR capacity and consequently a cost-benefit reliability constrained UC schedule. In addition, a powerful solution technique called 'integer-coded genetic algorithm (ICGA)' is being used for the solution of the proposed method. Numerical results on the IEEE reliability test system show that the consideration of transmission network unavailability has an important influence on reliability indices of the UC schedules
International Nuclear Information System (INIS)
Azizipanah-Abarghooee, Rasoul; Golestaneh, Faranak; Gooi, Hoay Beng; Lin, Jeremy; Bavafa, Farhad; Terzija, Vladimir
2016-01-01
Highlights: • Suggesting a new UC mixing a probabilistic security and incentive demand response. • Investigating the effects of uncertainty on UC using chance-constraint programming. • Proposing an efficient spinning reserve satisfaction based on a new ED correction. • Presenting a new operational cycles way to convert binary variable to discrete one. - Abstract: We propose a probabilistic unit commitment problem with incentive-based demand response and high level of wind power. Our novel formulation provides an optimal allocation of up/down spinning reserve. A more efficient unit commitment algorithm based on operational cycles is developed. A multi-period elastic residual demand economic model based on the self- and cross-price elasticities and customers’ benefit function is used. In the proposed scheme, the probability of residual demand falling within the up/down spinning reserve imposed by n − 1 security criterion is considered as a stochastic constraint. A chance-constrained method, with a new iterative economic dispatch correction, wind power curtailment, and commitment of cheaper units, is applied to guarantee that the probability of loss of load is lower than a pre-defined risk level. The developed architecture builds upon an improved Jaya algorithm to generate feasible, robust and optimal solutions corresponding to the operational cost. The proposed framework is applied to a small test system with 10 units and also to the IEEE 118-bus system to illustrate its advantages in efficient scheduling of generation in the power systems.
Wang, Fengyu
Traditional deterministic reserve requirements rely on ad-hoc, rule of thumb methods to determine adequate reserve in order to ensure a reliable unit commitment. Since congestion and uncertainties exist in the system, both the quantity and the location of reserves are essential to ensure system reliability and market efficiency. The modeling of operating reserves in the existing deterministic reserve requirements acquire the operating reserves on a zonal basis and do not fully capture the impact of congestion. The purpose of a reserve zone is to ensure that operating reserves are spread across the network. Operating reserves are shared inside each reserve zone, but intra-zonal congestion may block the deliverability of operating reserves within a zone. Thus, improving reserve policies such as reserve zones may improve the location and deliverability of reserve. As more non-dispatchable renewable resources are integrated into the grid, it will become increasingly difficult to predict the transfer capabilities and the network congestion. At the same time, renewable resources require operators to acquire more operating reserves. With existing deterministic reserve requirements unable to ensure optimal reserve locations, the importance of reserve location and reserve deliverability will increase. While stochastic programming can be used to determine reserve by explicitly modelling uncertainties, there are still scalability as well as pricing issues. Therefore, new methods to improve existing deterministic reserve requirements are desired. One key barrier of improving existing deterministic reserve requirements is its potential market impacts. A metric, quality of service, is proposed in this thesis to evaluate the price signal and market impacts of proposed hourly reserve zones. Three main goals of this thesis are: 1) to develop a theoretical and mathematical model to better locate reserve while maintaining the deterministic unit commitment and economic dispatch
Solving unit commitment and economic load dispatch problems ...
African Journals Online (AJOL)
2 Department of Electrical Power and Machines, Faculty of engineering, Ain shams ... intricate basic leadership process and it is hard to build up any thorough ... These pre-committed schedules are optimized by BAT algorithm thus .... and the current best location (solution) is x0 which is situated in the wake of looking at.
Commitment and dispatch of heat and power units via affinely adjustable robust optimization
DEFF Research Database (Denmark)
Zugno, Marco; Morales González, Juan Miguel; Madsen, Henrik
2016-01-01
compromising computational tractability. We perform an extensive numerical study based on data from the Copenhagen area in Denmark, which highlights important features of the proposed model. Firstly, we illustrate commitment and dispatch choices that increase conservativeness in the robust optimization...... and conservativeness of the solution. Finally, we perform a thorough comparison with competing models based on deterministic optimization and stochastic programming. (C) 2016 Elsevier Ltd. All rights reserved....
DEFF Research Database (Denmark)
Rong, Aiying; Hakonen, Henri; Lahdelma, Risto
2008-01-01
introduce in this paper the DP-RSC1 algorithm, which is a variant of the dynamic programming (DP) algorithm based on linear relaxation of the ON/OFF states of the units and sequential commitment of units one by one. The time complexity of DP-RSC1 is proportional to the number of generating units...
Directory of Open Access Journals (Sweden)
Marta Pieszko
Full Text Available Differentiation of one life-cycle stage to the next is critical for survival and transmission of apicomplexan parasites. A number of studies have shown that stage differentiation is a stochastic process and is associated with a point that commits the cell to a change over in the pattern of gene expression. Studies on differentiation to merozoite production (merogony in T. annulata postulated that commitment involves a concentration threshold of DNA binding proteins and an auto-regulatory loop.In this study ApiAP2 DNA binding proteins that show changes in expression level during merogony of T. annulata have been identified. DNA motifs bound by orthologous domains in Plasmodium were found to be enriched in upstream regions of stage-regulated T. annulata genes and validated as targets for the T. annulata AP2 domains by electrophoretic mobility shift assay (EMSA. Two findings were of particular note: the gene in T. annulata encoding the orthologue of the ApiAP2 domain in the AP2-G factor that commits Plasmodium to gametocyte production, has an expression profile indicating involvement in transmission of T. annulata to the tick vector; genes encoding related domains that bind, or are predicted to bind, sequence motifs of the type 5'-(ACACAC(A are implicated in differential regulation of gene expression, with one gene (TA11145 likely to be preferentially up-regulated via auto-regulation as the cell progresses to merogony.We postulate that the Theileria factor possessing the AP2 domain orthologous to that of Plasmodium AP2-G may regulate gametocytogenesis in a similar manner to AP2-G. In addition, paralogous ApiAP2 factors that recognise 5'-(ACACAC(A type motifs could operate in a competitive manner to promote reversible progression towards the point that commits the cell to undergo merogony. Factors possessing AP2 domains that bind (or are predicted to bind this motif are present in the vector-borne genera Theileria, Babesia and Plasmodium, and other
Neural Based Tabu Search method for solving unit commitment problem with cooling-banking constraints
Directory of Open Access Journals (Sweden)
Rajan Asir Christober Gnanakkan Charles
2009-01-01
Full Text Available This paper presents a new approach to solve short-term unit commitment problem (UCP using Neural Based Tabu Search (NBTS with cooling and banking constraints. The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. This also means that it is desirable to find the optimal generating unit commitment in the power system for next H hours. A 7-unit utility power system in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different IEEE test systems consist of 10, 26 and 34 units. Numerical results are shown to compare the superiority of the cost solutions obtained using the Tabu Search (TS method, Dynamic Programming (DP and Lagrangian Relaxation (LR methods in reaching proper unit commitment.
Economic MPC for a linear stochastic system of energy units
DEFF Research Database (Denmark)
Jørgensen, John Bagterp; Sokoler, Leo Emil; Standardi, Laura
2016-01-01
This paper summarizes comprehensively the work in four recent PhD theses from the Technical University of Denmark related to Economic MPC of future power systems. Future power systems will consist of a large number of decentralized power producers and a large number of controllable power consumers...... in addition to stochastic power producers such as wind turbines and solar power plants. Control of such large scale systems requires new control algorithms. In this paper, we formulate the control of such a system as an Economic Model Predictive Control (MPC) problem. When the power producers and controllable...... power consumers have linear dynamics, the Economic MPC may be expressed as a linear program. We provide linear models for a number of energy units in an energy system, formulate an Economic MPC for coordination of such a system. We indicate how advances in computational MPC makes the solutions...
An evolutionary programming based simulated annealing method for solving the unit commitment problem
Energy Technology Data Exchange (ETDEWEB)
Christober Asir Rajan, C. [Department of EEE, Pondicherry Engineering College, Pondicherry 605014 (India); Mohan, M.R. [Department of EEE, Anna University, Chennai 600 025 (India)
2007-09-15
This paper presents a new approach to solve the short-term unit commitment problem using an evolutionary programming based simulated annealing method. The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. This also means that it is desirable to find the optimal generating unit commitment in the power system for the next H hours. Evolutionary programming, which happens to be a global optimisation technique for solving unit commitment Problem, operates on a system, which is designed to encode each unit's operating schedule with regard to its minimum up/down time. In this, the unit commitment schedule is coded as a string of symbols. An initial population of parent solutions is generated at random. Here, each schedule is formed by committing all the units according to their initial status (''flat start''). Here the parents are obtained from a pre-defined set of solution's, i.e. each and every solution is adjusted to meet the requirements. Then, a random recommitment is carried out with respect to the unit's minimum down times. And SA improves the status. The best population is selected by evolutionary strategy. The Neyveli Thermal Power Station (NTPS) Unit-II in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different power systems consists of 10, 26, 34 generating units. Numerical results are shown comparing the cost solutions and computation time obtained by using the Evolutionary Programming method and other conventional methods like Dynamic Programming, Lagrangian Relaxation and Simulated Annealing and Tabu Search in reaching proper unit commitment. (author)
Reviving the United States' Commitment to Pakistan and Afghanistan
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Dr. Steve Young
2009-01-01
Full Text Available As President Obama is in the midst of deciding whether additional U.S.combat forces are needed in Afghanistan in addition to the 21,000 troops recently committed, he must realize that additional armed forces are only a stopgap measure in Afghanistan's downward spiral into an 'undergoverned' failed state. Similarly, as Pakistan's fragile and fractured civilian government continues to appease the Tehrik-i-Taliban Pakistan (TTP, an umbrella organization of Pakistani Pashtun tribesmen with Taliban cultural values led by Baitullah Mehsud and others, it comes closer to the concept of a "misgoverned" failed state, possessing a small arsenal of nuclear arms. The problem for the U.S. administration is that neither of these countries can be allowed to fall further into disrepair. At the same time each requires a different and unique approach to the threat of "Talibanization" that faces each country—the control of territory within each country by Islamic radicals seeking to impose their ultraconservative interpretation of shar'ia law onto the general populace. Generally acknowledged is the belief that what has tentatively worked in Iraq, that is, the additional U.S. troops and employment of former Sunni insurgents to help fight foreign fighters associated with al-Qaida, will not work in either Afghanistan or Pakistan. While a regional approach to the conflict in these two countries is warranted, Afghanistan and Pakistan are on two different economic, social, and political playing fields. Hence, there cannot be a one-size-fits-all solution for the two countries, especially one that draws on the Iraq playbook. In addition to its internal political problems, Pakistan also faces the issue of al-Qaida and Taliban training camps positioned in its literal back yard, the Federally Administered Tribal Areas (FATA or Tribal Areas. Resolution of the War on Terror cannot come to fruition without addressing the problems that exist in the Tribal Areas. This largely
Practical Robust Optimization Method for Unit Commitment of a System with Integrated Wind Resource
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Yuanchao Yang
2017-01-01
Full Text Available Unit commitment, one of the significant tasks in power system operations, faces new challenges as the system uncertainty increases dramatically due to the integration of time-varying resources, such as wind. To address these challenges, we propose the formulation and solution of a generalized unit commitment problem for a system with integrated wind resources. Given the prespecified interval information acquired from real central wind forecasting system for uncertainty representation of nodal wind injections with their correlation information, the proposed unit commitment problem solution is computationally tractable and robust against all uncertain wind power injection realizations. We provide a solution approach to tackle this problem with complex mathematical basics and illustrate the capabilities of the proposed mixed integer solution approach on the large-scale power system of the Northwest China Grid. The numerical results demonstrate that the approach is realistic and not overly conservative in terms of the resulting dispatch cost outcomes.
Fat Tail Model for Simulating Test Systems in Multiperiod Unit Commitment
Directory of Open Access Journals (Sweden)
J. A. Marmolejo
2015-01-01
Full Text Available This paper describes the use of Chambers-Mallows-Stuck method for simulating stable random variables in the generation of test systems for economic analysis in power systems. A study that focused on generating test electrical systems through fat tail model for unit commitment problem in electrical power systems is presented. Usually, the instances of test systems in Unit Commitment are generated using normal distribution, but in this work, simulations data are based on a new method. For simulating, we used three original systems to obtain the demand behavior and thermal production costs. The estimation of stable parameters for the simulation of stable random variables was based on three generally accepted methods: (a regression, (b quantiles, and (c maximum likelihood, choosing one that has the best fit of the tails of the distribution. Numerical results illustrate the applicability of the proposed method by solving several unit commitment problems.
Column Generation for Transmission Switching of Electricity Networks with Unit Commitment
DEFF Research Database (Denmark)
Villumsen, Jonas Christoffer; Philpott, Andy B.
2011-01-01
This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig...
A PSO based Artificial Neural Network approach for short term unit commitment problem
Directory of Open Access Journals (Sweden)
AFTAB AHMAD
2010-10-01
Full Text Available Unit commitment (UC is a non-linear, large scale, complex, mixed-integer combinatorial constrained optimization problem. This paper proposes, a new hybrid approach for generating unit commitment schedules using swarm intelligence learning rule based neural network. The training data has been generated using dynamic programming for machines without valve point effects and using genetic algorithm for machines with valve point effects. A set of load patterns as inputs and the corresponding unit generation schedules as outputs are used to train the network. The neural network fine tunes the best results to the desired targets. The proposed approach has been validated for three thermal machines with valve point effects and without valve point effects. The results are compared with the approaches available in the literature. The PSO-ANN trained model gives better results which show the promise of the proposed methodology.
An efficient chaos embedded hybrid approach for hydro-thermal unit commitment problem
International Nuclear Information System (INIS)
Yuan, Xiaohui; Ji, Bin; Yuan, Yanbin; Ikram, Rana M.; Zhang, Xiaopan; Huang, Yuehua
2015-01-01
Highlights: • Thermal unit commitment is considered in hydrothermal generation scheduling (SHTGS). • Two newly proposed promising optimization algorithms are combined to solving SHTGS. • The proposed method is enhanced by integrating a chaotic local search strategy. • Heuristic search strategies are applied to handle the constraints of the SHTGS. • The results verify the proposed method is feasible and efficient for handling SHTGS. - Abstract: This paper establishes a model to deal with the short-term hydrothermal generation scheduling (SHTGS) problem. The problem is composed of three interconnected parts: short-term hydrothermal coordination, thermal unit commitment and economic load dispatch. An efficient hybrid method composed of chaotic backtracking search optimization algorithm and binary charged system search algorithm (CBSA–BCSS) is proposed to solve this problem. In order to analyze the effect of the chaotic map on the performance of the method, three different chaotic maps are adopted to integrate into the proposed method and the corresponding consequences are achieved. Furthermore, efficient heuristic search strategies are adopted to handle with the complicated constraints of the SHTGS system. Finally, a hydrothermal unit commitment system is utilized to verify the feasibility and effectiveness of the proposed method. The results demonstrate the efficiency of the hybrid optimization method and the appropriation of the constraint handling strategies. The comparison of the solutions achieved by different methods shows that the proposed method has higher efficiency in terms of solving SHTGS problem
Guo, Sangang
2017-09-01
There are two stages in solving security-constrained unit commitment problems (SCUC) within Lagrangian framework: one is to obtain feasible units’ states (UC), the other is power economic dispatch (ED) for each unit. The accurate solution of ED is more important for enhancing the efficiency of the solution to SCUC for the fixed feasible units’ statues. Two novel methods named after Convex Combinatorial Coefficient Method and Power Increment Method respectively based on linear programming problem for solving ED are proposed by the piecewise linear approximation to the nonlinear convex fuel cost functions. Numerical testing results show that the methods are effective and efficient.
Mohammad Javad Abdollahi; Majid Moazzami
2015-01-01
In this paper security constraints unit commitment (SCUC) in the presence of wind power resources and electrical vehicles to grid is presented. SCUC operation prepare an optimal time table for generation unit commitment in order to maximize security, minimize operation cost and satisfy the constraints of networks and units in a period of time, as one of the most important research interest in power systems. Today, the relationship between power network and energy storage systems is interested...
International Nuclear Information System (INIS)
Stoilov, D.
2001-01-01
The first part of the parer considers the general problem of optimal yearly unit commitment in the new economical conditions in Bulgaria. The second part deals with non-convex problem , taking into account some costs for starting and stopping of power systems. The transition from yearly commitment to weekly or daily dispatching is commented
Optimisasi Unit Commitment Mempertimbangkan Fungsi Biaya Tidak Mulus Dengan Firefly Algorithm
Directory of Open Access Journals (Sweden)
Benny Prastikha Hadhi
2014-03-01
Full Text Available Setiap unit pembangkit yang beroperasi untuk memenuhi permintaan beban mempunyai jadwal operasi yang berbeda-beda. Hal ini disebabkan oleh perbedaan karakteristik input-output yang khas dari setiap unit. Untuk memperoleh biaya total pembangkitan yang ekonomis dibutuhkan penjadwalan nyala-padam unit pembangkit yang terhubung pada sistem tenaga listrik, yang dikenal sebagai unit commitment (UC. Penjadwalan unit pembangkit pada suatu sistem tenaga listrik memiliki banyak pertimbangan, seperti cadangan berputar (spinning reserve, waktu menyala minimal (minimum up time, waktu padam minimal (minimum down time, rentang daya output unit pembangkit dan lain-lain. Selain itu, fungsi biaya pembangkitan unit yang mengoperasikan katup uap untuk mengimbangi perubahan beban menyebabkan persamaan fungsi biaya menjadi tidak mulus. Fungsi biaya tidak mulus mempersulit penjadwalan ekonomis unit pembangkit. Tugas akhir ini mengajukan Firefly Algorithm (FA untuk menyelesaikan penjadwalan UC. FA merupakan algoritma yang sederhana, tetapi handal dalam menyelesaikan permasalahan optimisasi. UC yang diajukan menggunakan fungsi biaya tidak mulus. Dengan metode tersebut, diharapkan permasalahan penjadwalan unit pembangkit dapat terselesaikan dengan baik dan optimal sehingga memperoleh biaya total pembangkitan yang ekonomis.
EP BASED PSO METHOD FOR SOLVING PROFIT BASED MULTI AREA UNIT COMMITMENT PROBLEM
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K. VENKATESAN
2015-04-01
Full Text Available This paper presents a new approach to solve the profit based multi area unit commitment problem (PBMAUCP using an evolutionary programming based particle swarm optimization (EPPSO method. The objective of this paper is to maximize the profit of generation companies (GENCOs with considering system social benefit. The proposed method helps GENCOs to make a decision, how much power and reserve should be sold in markets, and how to schedule generators in order to receive the maximum profit. Joint operation of generation resources can result in significant operational cost savings. Power transfer between the areas through the tie lines depends upon the operating cost of generation at each hour and tie line transfer limits. The tie line transfer limits were considered as a set of constraints during optimization process to ensure the system security and reliability. The overall algorithm can be implemented on an IBM PC, which can process a fairly large system in a reasonable period of time. Case study of four areas with different load pattern each containing 7 units (NTPS and 26 units connected via tie lines have been taken for analysis. Numerical results showed comparing the profit of evolutionary programming-based particle swarm optimization method (EPPSO with conventional dynamic programming (DP, evolutionary programming (EP, and particle swarm optimization (PSO method. Experimental results shows that the application of this evolutionary programming based particle swarm optimization method have the potential to solve profit based multi area unit commitment problem with lesser computation time.
A new three-stage method for solving unit commitment problem
Energy Technology Data Exchange (ETDEWEB)
Khanmohammadi, S.; Amiri, M.; Haque, M. Tarafdar [Faculty of Electrical and Computer Engineering, University of Tabriz, P.O. Box 51665-343, Tabriz (Iran)
2010-07-15
This paper presents a new Three-Stage (THS) approach for solving Unit Commitment (UC) problem. The proposed method has a simple procedure to get at favorite solutions in a feasible duration of time by producing a primal schedule of status of units at the first step. In the second step the operating units take hourly values by doing Economic Dispatch (ED) on them via a hybrid serial algorithm of Artificial Intelligence (AI) including Particle Swarm Optimization (PSO) and Nelder-Mead (NM) algorithms. In spite of the acceptable solutions obtained by these two stages, the presented method takes another step called the solution modification process (SMP) to reach a more suitable solution. The simulation results over some standard cases of UC problem confirm that this method produces robust solutions and generally gets appropriate near-optimal solutions. (author)
Directory of Open Access Journals (Sweden)
C. Christober Asir Rajan
2008-06-01
Full Text Available The objective of this paper is to find the generation scheduling such that the total operating cost can be minimized, when subjected to a variety of constraints. This also means that it is desirable to find the optimal unit commitment in the power system for the next H hours. A 66-bus utility power system in India demonstrates the effectiveness of the proposed approach; extensive studies have also been performed for different IEEE test systems consist of 24, 57 and 175 buses. Numerical results are shown comparing the cost solutions and computation time obtained by different intelligence and conventional methods.
Energy Technology Data Exchange (ETDEWEB)
Reddy, N.M.; Reddy, K.R. [G. Narayanamma Inst. of Technology and Science, Hyderabad (India). Dept. of Electrical Engineering; Ramana, N.V. [JNTU College of Engineering, Jagityala (India). Dept. of Electrical Engineering
2008-07-01
Thermal power plants consist of several generating units with different generating capacities, fuel cost per MWH generated, minimum up/down times, and start-up or shut-down costs. The Unit Commitment (UC) problem in power systems involves determining the start-up and shut-down schedules of thermal generating units to meet forecasted load over a future short term for a period of one to seven days. This paper presented a new approach for the most complex UC problem using agglomerative and divisive hierarchical clustering. Euclidean costs, which are a measure of differences in fuel cost and start-up costs of any two units, were first calculated. Then, depending on the value of Euclidean costs, similar type of units were placed in a cluster. The proposed methodology has 2 individual algorithms. An agglomerative cluster algorithm is used while the load is increasing, and a divisive cluster algorithm is used when the load is decreasing. A search was conducted for an optimal solution for a minimal number of clusters and cluster data points. A standard ten-unit thermal unit power system was used to test and evaluate the performance of the method for a period of 24 hours. The new approach proved to be quite effective and satisfactory. 15 refs., 9 tabs., 5 figs.
Application of enhanced discrete differential evolution approach to unit commitment problem
International Nuclear Information System (INIS)
Yuan Xiaohui; Su Anjun; Nie Hao; Yuan Yanbin; Wang Liang
2009-01-01
This paper proposes a discrete binary differential evolution (DBDE) approach to solve the unit commitment problem (UCP). The proposed method is enhanced by priority list based on the unit characteristics and heuristic search strategies to handle constraints effectively. The implementation of the proposed method for UCP consists of three stages. Firstly, the DBDE based on priority list is applied for unit scheduling when neglecting the minimum up/down time constraints. Secondly, repairing strategies are used to handle the minimum up/down time constraints and decommit excess spinning reserve units. Finally, heuristic unit substitution search and gray zone modification algorithm are used to improve optimal solution further. Furthermore, the effects of two crucial parameters on performance of the DBDE for solving UCP are studied as well. To verify the advantages of the method, the proposed method is tested and compared to the other methods on the systems with the number of units in the range of 10-100. Numerical results demonstrate that the proposed method is superior to other methods reported in the literature.
Scalable unit commitment by memory-bounded ant colony optimization with A{sup *} local search
Energy Technology Data Exchange (ETDEWEB)
Saber, Ahmed Yousuf; Alshareef, Abdulaziz Mohammed [Department of Electrical and Computer Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589 (Saudi Arabia)
2008-07-15
Ant colony optimization (ACO) is successfully applied in optimization problems. Performance of the basic ACO for small problems with moderate dimension and searching space is satisfactory. As the searching space grows exponentially in the large-scale unit commitment problem, the basic ACO is not applicable for the vast size of pheromone matrix of ACO in practical time and physical computer-memory limit. However, memory-bounded methods prune the least-promising nodes to fit the system in computer memory. Therefore, the authors propose memory-bounded ant colony optimization (MACO) in this paper for the scalable (no restriction for system size) unit commitment problem. This MACO intelligently solves the limitation of computer memory, and does not permit the system to grow beyond a bound on memory. In the memory-bounded ACO implementation, A{sup *} heuristic is introduced to increase local searching ability and probabilistic nearest neighbor method is applied to estimate pheromone intensity for the forgotten value. Finally, the benchmark data sets and existing methods are used to show the effectiveness of the proposed method. (author)
Optimal Thermal Unit Commitment Solution integrating Renewable Energy with Generator Outage
Directory of Open Access Journals (Sweden)
S. Sivasakthi
2017-06-01
Full Text Available The increasing concern of global climate changes, the promotion of renewable energy sources, primarily wind generation, is a welcome move to reduce the pollutant emissions from conventional power plants. Integration of wind power generation with the existing power network is an emerging research field. This paper presents a meta-heuristic algorithm based approach to determine the feasible dispatch solution for wind integrated thermal power system. The Unit Commitment (UC process aims to identify the best feasible generation scheme of the committed units such that the overall generation cost is reduced, when subjected to a variety of constraints at each time interval. As the UC formulation involves many variables and system and operational constraints, identifying the best solution is still a research task. Nowadays, it is inevitable to include power system reliability issues in operation strategy. The generator failure and malfunction are the prime influencing factor for reliability issues hence they have considered in UC formulation of wind integrated thermal power system. The modern evolutionary algorithm known as Grey Wolf Optimization (GWO algorithm is applied to solve the intended UC problem. The potential of the GWO algorithm is validated by the standard test systems. Besides, the ramp rate limits are also incorporated in the UC formulation. The simulation results reveal that the GWO algorithm has the capability of obtaining economical resolutions with good solution quality.
Modeling and Optimization of the Medium-Term Units Commitment of Thermal Power
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Shengli Liao
2015-11-01
Full Text Available Coal-fired thermal power plants, which represent the largest proportion of China’s electric power system, are very sluggish in responding to power system load demands. Thus, a reasonable and feasible scheme for the medium-term optimal commitment of thermal units (MOCTU can ensure that the generation process runs smoothly and minimizes the start-up and shut-down times of thermal units. In this paper, based on the real-world and practical demands of power dispatch centers in China, a flexible mathematical model for MOCTU that uses equal utilization hours for the installed capacity of all thermal power plants as the optimization goal and that considers the award hours for MOCTU is developed. MOCTU is a unit commitment (UC problem with characteristics of large-scale, high dimensions and nonlinearity. For optimization, an improved progressive optimality algorithm (IPOA offering the advantages of POA is adopted to overcome the drawback of POA of easily falling into the local optima. In the optimization process, strategies of system operating capacity equalization and single station operating peak combination are introduced to move the target solution from the boundary constraints along the target isopleths into the feasible solution’s interior to guarantee the global optima. The results of a case study consisting of nine thermal power plants with 27 units show that the presented algorithm can obtain an optimal solution and is competent in solving the MOCTU with high efficiency and accuracy as well as that the developed simulation model can be applied to practical engineering needs.
Improved gravitational search algorithm for unit commitment considering uncertainty of wind power
International Nuclear Information System (INIS)
Ji, Bin; Yuan, Xiaohui; Chen, Zhihuan; Tian, Hao
2014-01-01
With increasing wind farm integrations, unit commitment (UC) is more difficult to solve because of the intermittent and fluctuation nature of wind power. In this paper, scenario generation and reduction technique is applied to simulate the impacts of its uncertainty on system operation. And then a model of thermal UC problem with wind power integration (UCW) is established. Combination of quantum-inspired binary gravitational search algorithm (GSA) and scenario analysis method is proposed to solve UCW problem. Meanwhile, heuristic search strategies are used to handle the constraints of thermal unit for each scenario. In addition, a priority list of thermal units based on the weight between average full-load cost and maximal power output is utilized during the optimization process. Moreover, two UC test systems with and without wind power integration are used to verify the feasibility and effectiveness of the proposed method as well as the performance of the algorithm. The results are analyzed in detail, which demonstrate the model and the proposed method is practicable. The comparison with other methods clearly shows that the proposed method has higher efficiency for solving UC problems with and even without wind farm integration. - Highlights: • Impact of wind fluctuation on unit commitment problem (UCW) is investigated. • Quantum-inspired gravitational search algorithm (QBGSA) is used to optimize UC. • A new method combines QBGSA with scenario analysis is proposed to solve UCW. • Heuristic search strategies are applied to handle the constraints of the UCW. • The results verify the proposed method is feasible and efficient for handling UCW
Unit Stratified Sampling as a Tool for Approximation of Stochastic Optimization Problems
Czech Academy of Sciences Publication Activity Database
Šmíd, Martin
2012-01-01
Roč. 19, č. 30 (2012), s. 153-169 ISSN 1212-074X R&D Projects: GA ČR GAP402/11/0150; GA ČR GAP402/10/0956; GA ČR GA402/09/0965 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : Stochastic programming * approximation * stratified sampling Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2013/E/smid-unit stratified sampling as a tool for approximation of stochastic optimization problems.pdf
Ranking Decision Making Units with Stochastic Data by Using Coefficient of Variation
Lotfi, F.; Nematollahi, N.; Behzadi, M.H.; Mirbolouki, M.
2010-01-01
Data Envelopment Analysis (DEA) is a non-parametric technique which is based on mathematical programming for evaluating the efficiency of a set of Decision Making Units (DMUs). Throughout applications, managers encounter with stochastic data and the necessity of having a method that is able to evaluate efficiency and rank efficient units has been under consideration. In this paper considering the concept of coefficient of variation among efficient DMUs, two ranking methods has been proposed. ...
Stochastic Analysis of a Queue Length Model Using a Graphics Processing Unit
Czech Academy of Sciences Publication Activity Database
Přikryl, Jan; Kocijan, J.
2012-01-01
Roč. 5, č. 2 (2012), s. 55-62 ISSN 1802-971X R&D Projects: GA MŠk(CZ) MEB091015 Institutional support: RVO:67985556 Keywords : graphics processing unit * GPU * Monte Carlo simulation * computer simulation * modeling Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2012/AS/prikryl-stochastic analysis of a queue length model using a graphics processing unit.pdf
Directory of Open Access Journals (Sweden)
Jaeyoon Lee
2018-05-01
Full Text Available The main purpose of this study was to investigate the impact of perceived HR practices on affective commitment and turnover intention. This study explored which HR practices were relatively more important in predicting affective commitment and turnover intention. A total of 302 employees from the United States and 317 from South Korea completed the same questionnaires for assessing the aforementioned relationships. The results illustrated that among perceived HR practices, internal mobility had the most significant association with turnover intention in both the United States and South Korea. While internal mobility was a stronger predictor of affective commitment for the United States sample, training was the most important variable for predicting affective commitment in South Korea. The second purpose of the study was to examine whether individuals’ positive affect influences the relationship between perceived HR practices and affective commitment and turnover intention. In the United States, positive affect moderated the relationship between perceived HR practices and affective commitment and turnover intention such that the relationships were stronger for individuals reporting high positive affect relative to those reporting low positive affect. However, these relationships were not significant in South Korea. We discuss the implications of these results, study limitations, and practical suggestions for future research.
International Nuclear Information System (INIS)
Koltsaklis, Nikolaos E.; Georgiadis, Michael C.
2015-01-01
Highlights: • A short-term structured investment planning model has been developed. • Unit commitment problem is incorporated into the long-term planning horizon. • Inherent intermittency of renewables is modelled in a comprehensive way. • The impact of CO_2 emission pricing in long-term investment decisions is quantified. • The evolution of system’s marginal price is evaluated for all the planning horizon. - Abstract: This work presents a generic mixed integer linear programming (MILP) model that integrates the unit commitment problem (UCP), i.e., daily energy planning with the long-term generation expansion planning (GEP) framework. Typical daily constraints at an hourly level such as start-up and shut-down related decisions (start-up type, minimum up and down time, synchronization, soak and desynchronization time constraints), ramping limits, system reserve requirements are combined with representative yearly constraints such as power capacity additions, power generation bounds of each unit, peak reserve requirements, and energy policy issues (renewables penetration limits, CO_2 emissions cap and pricing). For modelling purposes, a representative day (24 h) of each month over a number of years has been employed in order to determine the optimal capacity additions, electricity market clearing prices, and daily operational planning of the studied power system. The model has been tested on an illustrative case study of the Greek power system. Our approach aims to provide useful insight into strategic and challenging decisions to be determined by investors and/or policy makers at a national and/or regional level by providing the optimal energy roadmap under real operating and design constraints.
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Sahbi Marrouchi
2018-02-01
Full Text Available Solving the Unit Commitment problem (UCP optimizes the combination of production units operations and determines the appropriate operational scheduling of each production units to satisfy the expected consumption which varies from one day to one month. Besides, each production unit is conducted to constraints that render this problem complex, combinatorial and nonlinear. In this paper, we proposed a new strategy based on the combination three optimization methods: Tabu search, Particle swarm optimization and Lagrangian relaxation methods in order to develop a proper unit commitment scheduling of the production units while reducing the production cost during a definite period. The proposed strategy has been implemented on a the IEEE 9 bus test system containing 3 production unit and the results were promising compared to strategies based on meta-heuristic and deterministic methods.
Model-based investigation of the electricity market. Unit commitment and power plant investments
International Nuclear Information System (INIS)
Sun, Ninghong
2013-01-01
The German Federal Government published its energy concept in September 2010 with a description of the road into the era of renewable energies. Therefore, the future renewable energy installed in Germany is expected to consist mostly of wind and solar, which are subject to intermittency of supply and significant fluctuations. The growing portion of energy generation by fluctuating sources is turning to a big challenge for the power plant unit commitment and the investment decisions as well. In this thesis, a fundamental electricity market model with combined modeling of these two aspects is developed. This model is subsequently applied to the German electricity market to investigate what kind of power plant investments are indispensable, considering the steadily increasing portion of energy generation from fluctuating sources, to ensure a reliable energy supply in a cost-effective way in the future. In addition, current energy policy in Germany regarding the use of renewable energy and nuclear energy is analyzed.
A Three-Stage Birandom Program for Unit Commitment with Wind Power Uncertainty
Directory of Open Access Journals (Sweden)
Na Zhang
2014-01-01
Full Text Available The integration of large-scale wind power adds a significant uncertainty to power system planning and operating. The wind forecast error is decreased with the forecast horizon, particularly when it is from one day to several hours ahead. Integrating intraday unit commitment (UC adjustment process based on updated ultra-short term wind forecast information is one way to improve the dispatching results. A novel three-stage UC decision method, in which the day-ahead UC decisions are determined in the first stage, the intraday UC adjustment decisions of subfast start units are determined in the second stage, and the UC decisions of fast-start units and dispatching decisions are determined in the third stage is presented. Accordingly, a three-stage birandom UC model is presented, in which the intraday hours-ahead forecasted wind power is formulated as a birandom variable, and the intraday UC adjustment event is formulated as a birandom event. The equilibrium chance constraint is employed to ensure the reliability requirement. A birandom simulation based hybrid genetic algorithm is designed to solve the proposed model. Some computational results indicate that the proposed model provides UC decisions with lower expected total costs.
Smart Grid Cost-Emission Unit Commitment via Co-Evolutionary Agents
Directory of Open Access Journals (Sweden)
Xiaohua Zhang
2016-10-01
Full Text Available In this paper, the uncertainty of wind, solar and load; smart charging and discharging of plug-in hybrid electric vehicles (PHEVs to and from various energy sources; and the coordination of wind, solar power, PHEVs and cost-emission are considered in the smart grid unit commitment (UC. First, a multi-scenario simulation is used in which a set of valid scenarios is considered for the uncertainties of wind and solar energy sources and load. Then the UC problem for the set of scenarios is decomposed into the optimization of interactive agents by multi-agent technology. Agents’ action is represented by a genetic algorithm with adaptive crossover and mutation operators. The adaptive co-evolution of agents is reached by adaptive cooperative multipliers. Finally, simulation is implemented on an example of a power system containing thermal units, a wind farm, solar power plants and PHEVs. The results show the effectiveness of the proposed method. Thermal units, wind, solar power and PHEVs are mutually complementarily by the adaptive cooperative mechanism. The adaptive multipliers’ updating strategy can save more computational time and further improve the efficiency.
Effect of the accuracy of price forecasting on profit in a Price Based Unit Commitment
International Nuclear Information System (INIS)
Delarue, Erik; Van Den Bosch, Pieterjan; D'haeseleer, William
2010-01-01
This paper discusses and quantifies the so-called loss of profit (i.e., the sub-optimality of profit) that can be expected in a Price Based Unit Commitment (PBUC), when incorrect price forecasts are used. For this purpose, a PBUC model has been developed and utilized, using Mixed Integer Linear Programming (MILP). Simulations are used to determine the relationship between the Mean Absolute Percentage Error (MAPE) of a certain price forecast and the loss of profit, for four different types of power plants. A Combined Cycle (CC) power plant and a pumped storage unit show highest sensitivity to incorrect forecasts. A price forecast with a MAPE of 15%, on average, yields 13.8% and 12.1% profit loss, respectively. A classic thermal power plant (coal fired) and cascade hydro unit are less affected by incorrect forecasts, with only 2.4% and 2.0% profit loss, respectively, at the same price forecast MAPE. This paper further demonstrates that if price forecasts show an average bias (upward or downward), using the MAPE as measure of the price forecast might not be sufficient to quantify profit loss properly. Profit loss in this case has been determined as a function of both shift and MAPE of the price forecast. (author)
Unit commitment and investment valuation of flexible biogas plants in German power markets
Energy Technology Data Exchange (ETDEWEB)
Hochloff, Patrick
2017-07-01
Biogas plants contribute a significant share of renewable energy sources (RES) to the electricity system. Most of them are designed to supply constant power generation. In the future biogas plants will most likely become more flexible, scheduling their power generation with respect to market prices. For this purpose power units need extended electrical capacity to convert the continuously produced gas as well as the gas held in storage. When constructing extended capacity at biogas plants, the flexibility premium is the main focus for about 8000 plants which were constructed before August 2014. Additional incomes as a result of selling at higher market prices have been considered, too. However, their relationship to the electrical capacity and storage size of biogas plants was unknown as was the impact on investment valuation. This work has shown how biogas plants with extended capacity can be analyzed when they are operated in power markets, in particular the power spot market and the control reserve markets. Models on the basis of unit commitment have been developed in order to obtain optimized schedules and financial parameters, such as gross income and net present value (NPV), when biogas plants with extended capacity capitalize on prices in each market. The models developed consider several use cases that describe possible ways of participating in German power markets, switching between static and variable gas supply, providing secondary and tertiary control reserve, and claiming the market and flexibility premium. Mixed integer linear programs (MILP) have been developed for the unit commitment of each use case. The model for the unit commitment of providing control reserve with biogas plants made significant progress compared to the state of the art and has been published in (Hochloff, Braun 2014). There are two ways to make use of this model. First of all, the model could be applied to plan daily schedules for the operation of gas plants located at a gas
Unit commitment and investment valuation of flexible biogas plants in German power markets
International Nuclear Information System (INIS)
Hochloff, Patrick
2017-01-01
Biogas plants contribute a significant share of renewable energy sources (RES) to the electricity system. Most of them are designed to supply constant power generation. In the future biogas plants will most likely become more flexible, scheduling their power generation with respect to market prices. For this purpose power units need extended electrical capacity to convert the continuously produced gas as well as the gas held in storage. When constructing extended capacity at biogas plants, the flexibility premium is the main focus for about 8000 plants which were constructed before August 2014. Additional incomes as a result of selling at higher market prices have been considered, too. However, their relationship to the electrical capacity and storage size of biogas plants was unknown as was the impact on investment valuation. This work has shown how biogas plants with extended capacity can be analyzed when they are operated in power markets, in particular the power spot market and the control reserve markets. Models on the basis of unit commitment have been developed in order to obtain optimized schedules and financial parameters, such as gross income and net present value (NPV), when biogas plants with extended capacity capitalize on prices in each market. The models developed consider several use cases that describe possible ways of participating in German power markets, switching between static and variable gas supply, providing secondary and tertiary control reserve, and claiming the market and flexibility premium. Mixed integer linear programs (MILP) have been developed for the unit commitment of each use case. The model for the unit commitment of providing control reserve with biogas plants made significant progress compared to the state of the art and has been published in (Hochloff, Braun 2014). There are two ways to make use of this model. First of all, the model could be applied to plan daily schedules for the operation of gas plants located at a gas
Røstad, Lars Dybsjord; Erichsen, Jeanette Christine
2012-01-01
In this thesis, we have developed a strategic optimization model of investments in infrastructure in the LNG value chain. The focus is on floating LNG production units: when they are a viable solution and what value they add to the LNG value chain. First a deterministic model is presented with focus on describing the value chain, before it is expanded to a multistage stochastic model with uncertain field sizes and gas prices. The objective is to maximize expected discounted profits through op...
Modelling high level system design and unit commitment for a microgrid
Energy Technology Data Exchange (ETDEWEB)
Hawkes, A.D. [Centre for Energy Policy and Technology, Imperial College London, London SW7 2AZ (United Kingdom); Leach, M.A. [Centre for Environmental Strategy, Faculty of Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom)
2009-07-15
This article develops a linear programming cost minimisation model for the high level system design and corresponding unit commitment of generators and storage within a microgrid; a set of energy resources working co-operatively to create a cost effective, reliable and environmentally friendly energy provision system. Previous work in this area is used as a basis for formulation of a new approach to this problem, with particular emphasis on why a microgrid is different to centralised generation or other grid-connected decentralised energy resources. Specifically, the model explicitly defines the amount of time that the microgrid would be expected to operate autonomously, and restricts flow of heat between microgrid participants to defined cases. The model developed is applied to a set of United Kingdom commercial load profiles, under best current estimates of energy prices and technology capital costs, to determine investment attractiveness of the microgrid. Sensitivity analysis of results to variations in energy prices is performed. The results broadly indicate that a microgrid can offer an economic proposition, although it is necessarily slightly more expensive than regular grid-connected decentralised generation. The analysis results have raised important questions regarding a fair method for settlement between microgrid participants, and game theory has been identified as a suitable tool to analyse aspects of this situation. (author)
Modelling high level system design and unit commitment for a microgrid
International Nuclear Information System (INIS)
Hawkes, A.D.; Leach, M.A.
2009-01-01
This article develops a linear programming cost minimisation model for the high level system design and corresponding unit commitment of generators and storage within a microgrid; a set of energy resources working co-operatively to create a cost effective, reliable and environmentally friendly energy provision system. Previous work in this area is used as a basis for formulation of a new approach to this problem, with particular emphasis on why a microgrid is different to centralised generation or other grid-connected decentralised energy resources. Specifically, the model explicitly defines the amount of time that the microgrid would be expected to operate autonomously, and restricts flow of heat between microgrid participants to defined cases. The model developed is applied to a set of United Kingdom commercial load profiles, under best current estimates of energy prices and technology capital costs, to determine investment attractiveness of the microgrid. Sensitivity analysis of results to variations in energy prices is performed. The results broadly indicate that a microgrid can offer an economic proposition, although it is necessarily slightly more expensive than regular grid-connected decentralised generation. The analysis results have raised important questions regarding a fair method for settlement between microgrid participants, and game theory has been identified as a suitable tool to analyse aspects of this situation. (author)
A Comparative Study of Three Different Mathematical Methods for Solving the Unit Commitment Problem
Directory of Open Access Journals (Sweden)
Mehmet Kurban
2009-01-01
Full Text Available The unit commitment (UC problem which is an important subject in power system engineering is solved by using Lagragian relaxation (LR, penalty function (PF, and augmented Lagrangian penalty function (ALPF methods due to their higher solution quality and faster computational time than metaheuristic approaches. This problem is considered to be a nonlinear programming-(NP- hard problem because it is nonlinear, mixed-integer, and nonconvex. These three methods used for solving the problem are based on dual optimization techniques. ALPF method which combines the algorithmic aspects of both LR and PF methods is firstly used for solving the UC problem. These methods are compared to each other based on feasible schedule for each stage, feasible cost, dual cost, duality gap, duration time, and number of iterations. The numerical results show that the ALPF method gives the best duality gap, feasible and dual cost instead of worse duration time and the number of iterations. The four-unit Tuncbilek thermal plant which is located in Kutahya region in Turkey is chosen as a test system in this study. The programs used for all the analyses are coded and implemented using general algebraic modeling system (GAMS.
Howlader, Harun Or Rashid; Matayoshi, Hidehito; Noorzad, Ahmad Samim; Muarapaz, Cirio Celestino; Senjyu, Tomonobu
2018-05-01
This paper presents a smart house-based power system for thermal unit commitment programme. The proposed power system consists of smart houses, renewable energy plants and conventional thermal units. The transmission constraints are considered for the proposed system. The generated power of the large capacity renewable energy plant leads to the violated transmission constraints in the thermal unit commitment programme, therefore, the transmission constraint should be considered. This paper focuses on the optimal operation of the thermal units incorporated with controllable loads such as Electrical Vehicle and Heat Pump water heater of the smart houses. The proposed method is compared with the power flow in thermal units operation without controllable loads and the optimal operation without the transmission constraints. Simulation results show the validation of the proposed method.
Bartlett, Kenneth; Kang, Dae-seok
2004-01-01
This study examines the relationship between employee attitudes towards training and organizational commitment among a sample of nurses in New Zealand and the United States. Results show that perceived access to training, training frequency, motivation to learn from training, benefits of training, and supervisory support for training were…
Restriction techniques for the unit-commitment problem with total procurement costs
International Nuclear Information System (INIS)
Kaleta, Mariusz; Toczylowski, Eugeniusz
2008-01-01
Many discrete optimization problems may be solved much easier, if the solution space can be restricted in a convenient way. For a given specific problem, the restriction techniques can be helpful if an available optimization solver, perceived as a black box, is capable of solving quickly only reduced subproblems of a limited size. For the family of hard unit-commitment problems we investigate a hierarchical search algorithm, which is based on decomposition of the problem into two subproblems. The upper-level subproblem is a relatively small decision 'kernel' of the problem that can be solved approximately by a search algorithm. We define an appropriate restricted decision space for this subproblem. The lower-level subproblem is an appropriate restriction of the original problem that can be solved efficiently by a dedicated solver. Our approach was analyzed on a set of historical data from the Polish electrical balancing market and the best known solutions were improved by the average of about 2-5%
Committed Vulnerability to Extreme Weather Events in the United States (Invited)
Preston, B. L.
2013-12-01
Despite improvements in disaster risk management in the United States, a trend toward increasing economic losses from extreme weather events has been observed. This trend has been attributed to growth in socioeconomic exposure to extremes driven by the concentration of population and wealth on hazardous landscapes. As geographic patterns of demography and economic development are associated with strong path dependence, the United States is ';locked-in' to future increases in exposure and associated economic losses in the decades ahead, irrespective of the influence of climate change. To understand the influence of path dependence on past and future losses, an index of potential socioeconomic exposure was developed at the U.S. county level based upon population size and inflation-adjusted wealth proxies. Since 1960, exposure has increased preferentially in the U.S. Southeast, particularly coastal and urban counties and Southwest relative to the Great Plains and Northeast. Projected changes in exposure from 2009 to 2054 based upon scenarios of future demographic and economic change suggest a long-term commitment to increasing, but spatially heterogeneous, exposure to extremes, independent of climate change. The implications of this path dependence are examined in the context of several natural hazards. Annualized county-level losses from 1960-2008 for five climate-related natural hazards were normalized to 2009 values and then scaled based upon projected changes in exposure and two different estimates of the exposure elasticity of losses. Results indicate that losses from extreme events will grow by a factor of 1.3-1.7 and 1.8-3.9 by 2025 and 2050, respectively, with the exposure elasticity representing a major source of uncertainty. At more local scales, however, such as rapidly growing metropolitan areas, losses are anticipated to grow more rapidly. As such, improving understanding of the societal implications of the extreme weather events of the future
A decomposition method for network-constrained unit commitment with AC power flow constraints
International Nuclear Information System (INIS)
Bai, Yang; Zhong, Haiwang; Xia, Qing; Kang, Chongqing; Xie, Le
2015-01-01
To meet the increasingly high requirement of smart grid operations, considering AC power flow constraints in the NCUC (network-constrained unit commitment) is of great significance in terms of both security and economy. This paper proposes a decomposition method to solve NCUC with AC power flow constraints. With conic approximations of the AC power flow equations, the master problem is formulated as a MISOCP (mixed integer second-order cone programming) model. The key advantage of this model is that the active power and reactive power are co-optimised, and the transmission losses are considered. With the AC optimal power flow model, the AC feasibility of the UC result of the master problem is checked in subproblems. If infeasibility is detected, feedback constraints are generated based on the sensitivity of bus voltages to a change in the unit reactive power generation. They are then introduced into the master problem in the next iteration until all AC violations are eliminated. A 6-bus system, a modified IEEE 30-bus system and the IEEE 118-bus system are used to validate the performance of the proposed method, which provides a satisfactory solution with approximately 44-fold greater computational efficiency. - Highlights: • A decomposition method is proposed to solve the NCUC with AC power flow constraints • The master problem considers active power, reactive power and transmission losses. • OPF-based subproblems check the AC feasibility using parallel computing techniques. • An effective feedback constraint interacts between the master problem and subproblem. • Computational efficiency is significantly improved with satisfactory accuracy
Using stochastic cell division and death to probe minimal units of cellular replication
Chib, Savita; Das, Suman; Venkatesan, Soumya; Sai Narain Seshasayee, Aswin; Thattai, Mukund
2018-03-01
The invariant cell initiation mass measured in bacterial growth experiments has been interpreted as a minimal unit of cellular replication. Here we argue that the existence of such minimal units induces a coupling between the rates of stochastic cell division and death. To probe this coupling we tracked live and dead cells in Escherichia coli populations treated with a ribosome-targeting antibiotic. We find that the growth exponent from macroscopic cell growth or decay measurements can be represented as the difference of microscopic first-order cell division and death rates. The boundary between cell growth and decay, at which the number of live cells remains constant over time, occurs at the minimal inhibitory concentration (MIC) of the antibiotic. This state appears macroscopically static but is microscopically dynamic: division and death rates exactly cancel at MIC but each is remarkably high, reaching 60% of the antibiotic-free division rate. A stochastic model of cells as collections of minimal replicating units we term ‘widgets’ reproduces both steady-state and transient features of our experiments. Sub-cellular fluctuations of widget numbers stochastically drive each new daughter cell to one of two alternate fates, division or death. First-order division or death rates emerge as eigenvalues of a stationary Markov process, and can be expressed in terms of the widget’s molecular properties. High division and death rates at MIC arise due to low mean and high relative fluctuations of widget number. Isolating cells at the threshold of irreversible death might allow molecular characterization of this minimal replication unit.
Directory of Open Access Journals (Sweden)
Mohammad Javad Abdollahi
2015-08-01
Full Text Available In this paper security constraints unit commitment (SCUC in the presence of wind power resources and electrical vehicles to grid is presented. SCUC operation prepare an optimal time table for generation unit commitment in order to maximize security, minimize operation cost and satisfy the constraints of networks and units in a period of time, as one of the most important research interest in power systems. Today, the relationship between power network and energy storage systems is interested for many researchers and network operators. Using Electrical Vehicles (PEVs and wind power for energy production is one of the newest proposed methods for replacing fossil fuels.One of the effective strategies for analyzing of the effects of Vehicle 2 Grid (V2G and wind power in optimal operation of generation is running of SCUC for power systems that are equipped with V2G and wind power resources. In this paper, game theory method is employed for deterministic solution of day-ahead unit commitment with considering security constraints in the simultaneous presence of V2G and wind power units. This problem for two scenarios of grid-controlled mode and consumer-controlled mode in three different days with light, medium and heavy load profiles is analyzed. Simulation results show the effectiveness of the presence of V2G and wind power for decreasing of generation cost and improving operation indices of power systems.
Self-scheduling and bidding strategies of thermal units with stochastic emission constraints
International Nuclear Information System (INIS)
Laia, R.; Pousinho, H.M.I.; Melíco, R.; Mendes, V.M.F.
2015-01-01
Highlights: • The management of thermal power plants is considered for different emission allowance levels. • The uncertainty on electricity price is considered by a set of scenarios. • A stochastic MILP approach allows devising the bidding strategies and hedging against price uncertainty and emission allowances. - Abstract: This paper is on the self-scheduling problem for a thermal power producer taking part in a pool-based electricity market as a price-taker, having bilateral contracts and emission-constrained. An approach based on stochastic mixed-integer linear programming approach is proposed for solving the self-scheduling problem. Uncertainty regarding electricity price is considered through a set of scenarios computed by simulation and scenario-reduction. Thermal units are modelled by variable costs, start-up costs and technical operating constraints, such as: forbidden operating zones, ramp up/down limits and minimum up/down time limits. A requirement on emission allowances to mitigate carbon footprint is modelled by a stochastic constraint. Supply functions for different emission allowance levels are accessed in order to establish the optimal bidding strategy. A case study is presented to illustrate the usefulness and the proficiency of the proposed approach in supporting biding strategies
2010-07-01
quid pro quo ). Examples of questions that were used in previous studies to measure crude/offensive behavior, as well as, other forms of sexual ...includes, but is not limited to, harassment in which submission is made a condition of employment (or quid pro quo ). Global or organizational...Effects of Sexual Harassment on Job Satisfaction, Retention, Cohesion, Commitment and Unit Effectiveness: The Case of the Air Force Dr. Brenda
Directory of Open Access Journals (Sweden)
Dayan Sun
2017-01-01
Full Text Available Because wind power spillage is barely considered, the existing robust unit commitment cannot accurately analyze the impacts of wind power accommodation on on/off schedules and spinning reserve requirements of conventional generators and cannot consider the network security limits. In this regard, a novel double-level robust security-constrained unit commitment formulation with optimizable interval of uncertain wind power output is firstly proposed in this paper to obtain allowable interval solutions for wind power generation and provide the optimal schedules for conventional generators to cope with the uncertainty in wind power generation. The proposed double-level model is difficult to be solved because of the invalid dual transform in solution process caused by the coupling relation between the discrete and continuous variables. Therefore, a two-stage iterative solution method based on Benders Decomposition is also presented. The proposed double-level model is transformed into a single-level and two-stage robust interval unit commitment model by eliminating the coupling relation, and then this two-stage model can be solved by Benders Decomposition iteratively. Simulation studies on a modified IEEE 26-generator reliability test system connected to a wind farm are conducted to verify the effectiveness and advantages of the proposed model and solution method.
DEFF Research Database (Denmark)
Rong, Aiying; Hakonen, Henri; Lahdelma, Risto
2009-01-01
efficiency of the plants. We introduce in this paper the DRDP-RSC algorithm, which is a dynamic regrouping based dynamic programming (DP) algorithm based on linear relaxation of the ON/OFF states of the units, sequential commitment of units in small groups. Relaxed states of the plants are used to reduce...... the dimension of the UC problem and dynamic regrouping is used to improve the solution quality. Numerical results based on real-life data sets show that this algorithm is efficient and optimal or near-optimal solutions with very small optimality gap are obtained....
International Nuclear Information System (INIS)
Hemmati, Reza; Saboori, Hedayat; Saboori, Saeid
2016-01-01
In recent decades, wind power resources have been integrated in the power systems increasingly. Besides confirmed benefits, utilization of large share of this volatile source in power generation portfolio has been faced system operators with new challenges in terms of uncertainty management. It is proved that energy storage systems are capable to handle projected uncertainty concerns. Risk-neutral methods have been proposed in the previous literature to schedule storage units considering wind resources uncertainty. Ignoring risk of the cost distributions with non-desirable properties may result in experiencing high costs in some unfavorable scenarios with high probability. In order to control the risk of the operator decisions, this paper proposes a new risk-constrained two-stage stochastic programming model to make optimal decisions on energy storage and thermal units in a transmission constrained hybrid wind-thermal power system. Risk-aversion procedure is explicitly formulated using the conditional value-at-risk measure, because of possessing distinguished features compared to the other risk measures. The proposed model is a mixed integer linear programming considering transmission network, thermal unit dynamics, and storage devices constraints. The simulations results demonstrate that taking the risk of the problem into account will affect scheduling decisions considerably depend on the level of the risk-aversion. - Highlights: • Risk of the operation decisions is handled by using risk-averse programming. • Conditional value-at-risk is used as risk measure. • Optimal risk level is obtained based on the cost/benefit analysis. • The proposed model is a two-stage stochastic mixed integer linear programming. • The unit commitment is integrated with ESSs and wind power penetration.
DEFF Research Database (Denmark)
Zhang, Yipu; Ai, Xiaomeng; Wen, Jinyu
2018-01-01
. In this paper, a novel data-adaptive robust optimization method for the unit commitment is proposed for the power system with wind farms integrated. The extreme scenario extraction and the two stage robust optimization are combined in the proposed method. The data-adaptive set consisting of a few extreme...... scenarios is derived to reduce the conservativeness by considering the temporal and spatial correlations of multiple wind farms. Numerical results demonstrate that the proposed data-adaptive robust optimization algorithm is less conservative than the current two-stage optimization approaches while maintains...
DEFF Research Database (Denmark)
Zhou, Bo; Ai, Xiaomeng; Fang, Jiakun
2017-01-01
With the rapid development and deployment of voltage source converter (VSC) based HVDC, the traditional power system is evolving to the hybrid AC-DC grid. New optimization methods are urgently needed for these hybrid AC-DC power systems. In this paper, mixed-integer second order cone programming...... (MISOCP) for the hybrid AC-DC power systems is proposed. The second order cone (SOC) relaxation is adopted to transform the AC and DC power flow constraints to MISOCP. Several IEEE test systems are used to validate the proposed MISCOP formulation of the optimal power flow (OPF) and unit commitment (UC...
International Nuclear Information System (INIS)
Yang, Zhile; Li, Kang; Niu, Qun; Xue, Yusheng
2017-01-01
Highlights: • A new UCsRP problem with flexible integrations is established. • A novel multi-zone sampling method is proposed for scenarios generation. • A meta-heuristic solving tool is introduced for solving the UCsRP problem. • A comprehensive study is conducted considering multiple weathers and seasons. • The economic effects of various scenarios are evaluated and compared. - Abstract: Significant penetration of renewable generations (RGs) and mass roll-out of plug-in electric vehicles (PEVs) will pay a vital role in delivering the low carbon energy future and low emissions of greenhouse gas (GHG) that are responsible for the global climate change. However, it is of considerable difficulties to precisely forecast the undispatchable and intermittent wind and solar power generations. The uncoordinated charging of PEVs imposes further challenges on the unit commitment in modern grid operations. In this paper, all these factors are comprehensively investigated for the first time within a novel hybrid unit commitment framework, namely UCsRP, which considers a wide range of scenarios in renewable generations and demand side management of dispatchable PEVs load. UCsRP is however an extremely challenging optimisation problem not only due to the large scale, mixed integer and nonlinearity, but also due to the double uncertainties relating to the renewable generations and PEV charging and discharging. In this paper, a meta-heuristic solving tool is introduced for solving the UCsRP problem. A key to improve the reliability of the unit commitment is to generate a range of scenarios based on multiple distributions of renewable generations under different prediction errors and extreme predicted value conditions. This is achieved by introducing a novel multi-zone sampling method. A comprehensive study considering four different cases of unit commitment problems with various weather and season scenarios using real power system data are conducted and solved, and smart
Directory of Open Access Journals (Sweden)
Nuchjarin Intalar
2015-07-01
Full Text Available Carbon tax policy is a cost-effective instrument for emission reduction. However, setting the carbon tax is one of the challenging task for policy makers as it will lead to higher price of emission-intensive sources especially the utility price. In a large-scale power generation system, minimizing the operational cost and the environmental impact are conflicting objectives and it is difficult to find the compromise solution. This paper proposes a methodology of finding a feasible carbon tax rate on strategic level using the operational unit commitment model. We present a multi-objective mixed integer linear programming model to solve the unit commitment problem and consider the environmental impacts. The methodology of analyzing of the effect of carbon tax rates on the power generation, operating cost, and CO2 emission is also provided. The trade-off relationship between total operating cost and total CO2 emission is presented in the Pareto-optimal curve to analyze the feasible carbon tax rate that is influencing on electricity operating cost. The significant outcome of this paper is a modeling framework for the policy makers to determine the possible carbon tax that can be imposed on the electricity generation.
Directory of Open Access Journals (Sweden)
Riza Fahmi Andriyanto
2017-01-01
Full Text Available Kebutuhan akan energi listrik terus menigkat seiring dengan perkembangan teknologi. meningkatnya beban listrik ini harus diimbangi dengan penambahan daya yang dibangkitkan. Hal ini sangat berpengaruh pada penjadwalan unit pembangkit yang harus ditentukan dengan baik agar didapatkan pembangkitan yang optimal. Pada Tugas Akhir ini mengambil topik mengenai unit commitment dan economic dispatch dengan mempertimbangkan nilai dari batasan generator (ramp-rate. Metode yang digunakan adalah complete enumeration dengan forward dynamic programming pada unit commitment dan quadratic programming pada economic dispatch. Metode - metode tersebut diterapkan dalam pemrograman matlab sehingga dapat dijadikan suatu program perhitungan unit commitment dan economic dispatch dengan mempertimbangkan nilai batasan ramp-rate. Dengan metode tersebut, diharapkan permasalahan penjadwalan unit pembangkit dapat terselesaikan dengan baik dan optimal sehingga memperoleh total biaya pembangkitan yang ekonomis.
Stochastic Robust Mathematical Programming Model for Power System Optimization
Energy Technology Data Exchange (ETDEWEB)
Liu, Cong; Changhyeok, Lee; Haoyong, Chen; Mehrotra, Sanjay
2016-01-01
This paper presents a stochastic robust framework for two-stage power system optimization problems with uncertainty. The model optimizes the probabilistic expectation of different worst-case scenarios with ifferent uncertainty sets. A case study of unit commitment shows the effectiveness of the proposed model and algorithms.
Stochastic Multicriteria Acceptability Analysis for Evaluation of Combined Heat and Power Units
Directory of Open Access Journals (Sweden)
Haichao Wang
2014-12-01
Full Text Available Combined heat and power (CHP is a promising technology that can contribute to energy efficiency and environmental protection. More CHP-based energy systems are planned for the future. This makes the evaluation and selection of CHP systems very important. In this paper, 16 CHP units representing different technologies are taken into account for multicriteria evaluation with respect to the end users’ requirements. These CHP technologies cover a wide range of power outputs and fuel types. They are evaluated from the energy, economy and environment (3E points of view, specifically including the criteria of efficiency, investment cost, electricity cost, heat cost, CO2 production and footprint. Uncertainties and imprecision are common both in criteria measurements and weights, therefore the stochastic multicriteria acceptability analysis (SMAA model is used in aiding this decision making problem. These uncertainties are treated better using a probability distribution function and Monte Carlo simulation in the model. Moreover, the idea of “feasible weight space (FWS” which represents the union of all preference information from decision makers (DMs is proposed. A complementary judgment matrix (CJM is introduced to determine the FWS. It can be found that the idea of FWS plus CJM is well compatible with SMAA and thus make the evaluation reliable.
International Nuclear Information System (INIS)
1994-01-01
Under the United Nations Framework Convention on Climate Change, countries must adopt measures to mitigate climate change, adapt to its possible effects, increase public awareness and scientific understanding of climate change and possible responses, and work together in all of these areas. A review is provided of action being currently taken by Canadian governments, non-governmental organizations, communities, and the private sector to meet domestic and international climate change commitments. Projections indicate that climate change could result in significant changes to many of Canada's natural ecosystems, with equally significant economic and social consequences. Canadian demand for energy is the chief cause of Canada's man-made emissions of greenhouse gases. As a first step in meeting its commitment, Canada is developing and implementing measures to limit greenhouse gas emissions, mainly in the area of energy efficiency, energy conservation, and switching to energy sources that are less carbon-intensive. Progress in limiting such emissions will be assessed via emissions inventories, examination of climatic change indicators, forecasting future energy-related emissions of the three primary greenhouse gases, and use of case studies to assess the effectiveness of emissions control measures. Other components of Canadian activities include increasing public awareness of climate change, sponsoring research on the subject, reviewing environmental policies, and international cooperation. 59 refs., 36 figs., 23 tabs
International Nuclear Information System (INIS)
Hipkin, J.
1977-01-01
In the United Kingdom tritium has become almost the only radionuclide that is used in luminising. Two distinct methods of luminising are used, one involving the use of tritium gas and the other involving the use of tritium activated luminous paint. All major luminisers have voluntarily taken part in urine monitoring programmes. The analyses have been carried out by the National Radiological Protection Board and estimates of committed dose equivalent have been made from the results. The work presented is an analysis of the committed dose equivalents received by all the individuals monitored in the years 1974, 1975 and 1976. It is shown that doses follow, in general, a lognormal distribution modified only at the high dose end by what must be described as dose management. Further evidence for dose management is seen when the pattern of dose versus time are analysed for selected individuals. It is shown that the maximum permissible dose as recommended by the International Commission on Radiological Protection, is only rarely exceeded. It is also shown that there is a substantial difference in the degree of exposure between workers involved in gaseous tritium luminising and workers using paint luminising. A comparison is made between exposure in gaseous tritium luminising and exposure in another common use of gaseous tritium, ie. the filling of electronic devices with tritium gas. It is shown that exposure is very much less in the electronic device work
Energy Technology Data Exchange (ETDEWEB)
Piperagkas, G.S.; Anastasiadis, A.G.; Hatziargyriou, N.D. [National Technical University of Athens, School of Electrical and Computer Engineering, Electric Power Division, 9, Iroon Polytechneiou Str., GR-15773 Zografou, Athens (Greece)
2011-01-15
In this paper an extended stochastic multi-objective model for economic dispatch (ED) is proposed, that incorporates in the optimization process heat and power from CHP units and expected wind power. Stochastic restrictions for the CO{sub 2}, SO{sub 2} and NO{sub x} emissions are used as inequality constraints. The ED problem is solved using a multi-objective particle swarm optimization technique. The available wind power is estimated from a transformation of the wind speed considered as a random variable to wind power. Simulations are performed on the modified IEEE 30 bus network with 2 cogeneration units and actual wind data. Results concerning minimum cost and emissions reduction options are finally drawn. (author)
DEFF Research Database (Denmark)
Zhang, Ning; Kang, Chongqing; Xia, Qing
2015-01-01
The integration of wind power requires the power system to be sufficiently flexible to accommodate its forecast errors. In the market clearing process, the scheduling of flexibility relies on the manner in which the wind power uncertainty is addressed in the unit commitment (UC) model. This paper...... and are considered in both the objective functions and the constraints. The RUC model is shown to be convex and is transformed into a mixed integer linear programming (MILP) problem using relaxation and piecewise linearization. The proposed RUC model is tested using a three-bus system and an IEEE RTS79 system...... that the risk modeling facilitates a strategic market clearing procedure with a reasonable computational expense....
Hemmati, Reza; Saboori, Hedayat
2016-05-01
Energy storage systems (ESSs) have experienced a very rapid growth in recent years and are expected to be a promising tool in order to improving power system reliability and being economically efficient. The ESSs possess many potential benefits in various areas in the electric power systems. One of the main benefits of an ESS, especially a bulk unit, relies on smoothing the load pattern by decreasing on-peak and increasing off-peak loads, known as load leveling. These devices require new methods and tools in order to model and optimize their effects in the power system studies. In this respect, this paper will model bulk ESSs based on the several technical characteristics, introduce the proposed model in the thermal unit commitment (UC) problem, and analyze it with respect to the various sensitive parameters. The technical limitations of the thermal units and transmission network constraints are also considered in the model. The proposed model is a Mixed Integer Linear Programming (MILP) which can be easily solved by strong commercial solvers (for instance CPLEX) and it is appropriate to be used in the practical large scale networks. The results of implementing the proposed model on a test system reveal that proper load leveling through optimum storage scheduling leads to considerable operation cost reduction with respect to the storage system characteristics.
Hemmati, Reza; Saboori, Hedayat
2016-01-01
Energy storage systems (ESSs) have experienced a very rapid growth in recent years and are expected to be a promising tool in order to improving power system reliability and being economically efficient. The ESSs possess many potential benefits in various areas in the electric power systems. One of the main benefits of an ESS, especially a bulk unit, relies on smoothing the load pattern by decreasing on-peak and increasing off-peak loads, known as load leveling. These devices require new methods and tools in order to model and optimize their effects in the power system studies. In this respect, this paper will model bulk ESSs based on the several technical characteristics, introduce the proposed model in the thermal unit commitment (UC) problem, and analyze it with respect to the various sensitive parameters. The technical limitations of the thermal units and transmission network constraints are also considered in the model. The proposed model is a Mixed Integer Linear Programming (MILP) which can be easily solved by strong commercial solvers (for instance CPLEX) and it is appropriate to be used in the practical large scale networks. The results of implementing the proposed model on a test system reveal that proper load leveling through optimum storage scheduling leads to considerable operation cost reduction with respect to the storage system characteristics. PMID:27222741
Fennell, Philip; Goldstein, Robert Lloyd
2006-01-01
Legal approaches to civil commitment in the United States and the United Kingdom are compared. A concise overview of the historical evolution of civil commitment in both countries precedes a discussion of the present scheme of commitment standards in each system. These current standards in U.S. and U.K. jurisdictions are then applied to a hypothetical case of delusional disorder. A discussion of the constructive use of civil commitment in patients with delusional disorder who may be dangerous focuses on its value as a preventive measure against potential harm to self or others, as well as the pros and cons of coercive assessment and treatment. Despite the many differences in approach to commitment, the authors concur that in both countries the patient with delusional disorder was committable before the commission of a serious criminal offense.
Baker, Phillip; Hawkes, Corinna; Wingrove, Kate; Parkhurst, Justin; Thow, Anne Marie; Walls, Helen
2018-01-01
Introduction Generating country-level political commitment will be critical to driving forward action throughout the United Nations Decade of Action on Nutrition (2016–2025). In this review of the empirical nutrition policy literature, we ask: what factors generate, sustain and constrain political commitment for nutrition, how and under what circumstances? Our aim is to inform strategic ‘commitment-building’ actions. Method We adopted a framework synthesis method and realist review protocol. An initial framework was derived from relevant theory and then populated with empirical evidence to test and modify it. Five steps were undertaken: initial theoretical framework development; search for relevant empirical literature; study selection and quality appraisal; data extraction, analysis and synthesis and framework modification. Results 75 studies were included. We identified 18 factors that drive commitment, organised into five categories: actors; institutions; political and societal contexts; knowledge, evidence and framing; and, capacities and resources. Irrespective of country-context, effective nutrition actor networks, strong leadership, civil society mobilisation, supportive political administrations, societal change and focusing events, cohesive and resonant framing, and robust data systems and available evidence were commitment drivers. Low-income and middle-income country studies also frequently reported international actors, empowered institutions, vertical coordination and capacities and resources. In upper-middle-income and high-income country studies, private sector interference frequently undermined commitment. Conclusion Political commitment is not something that simply exists or emerges accidentally; it can be created and strengthened over time through strategic action. Successfully generating commitment will likely require a core set of actions with some context-dependent adaptations. Ultimately, it will necessitate strategic actions by cohesive
Baker, Phillip; Hawkes, Corinna; Wingrove, Kate; Demaio, Alessandro Rhyl; Parkhurst, Justin; Thow, Anne Marie; Walls, Helen
2018-01-01
Generating country-level political commitment will be critical to driving forward action throughout the United Nations Decade of Action on Nutrition (2016-2025). In this review of the empirical nutrition policy literature, we ask: what factors generate, sustain and constrain political commitment for nutrition, how and under what circumstances? Our aim is to inform strategic 'commitment-building' actions. We adopted a framework synthesis method and realist review protocol. An initial framework was derived from relevant theory and then populated with empirical evidence to test and modify it. Five steps were undertaken: initial theoretical framework development; search for relevant empirical literature; study selection and quality appraisal; data extraction, analysis and synthesis and framework modification. 75 studies were included. We identified 18 factors that drive commitment, organised into five categories: actors; institutions; political and societal contexts; knowledge, evidence and framing; and, capacities and resources. Irrespective of country-context, effective nutrition actor networks, strong leadership, civil society mobilisation, supportive political administrations, societal change and focusing events, cohesive and resonant framing, and robust data systems and available evidence were commitment drivers. Low-income and middle-income country studies also frequently reported international actors, empowered institutions, vertical coordination and capacities and resources. In upper-middle-income and high-income country studies, private sector interference frequently undermined commitment. Political commitment is not something that simply exists or emerges accidentally; it can be created and strengthened over time through strategic action. Successfully generating commitment will likely require a core set of actions with some context-dependent adaptations. Ultimately, it will necessitate strategic actions by cohesive, resourced and strongly led nutrition actor
International Nuclear Information System (INIS)
Sun, Yanan; Dong, Jizhe; Ding, Lijuan
2017-01-01
Highlights: • A day–ahead wind–thermal unit commitment model is presented. • Wind speed transfer matrix is formed to depict the sequential wind features. • Spinning reserve setting considering wind power accuracy and variation is proposed. • Verified study is performed to check the correctness of the program. - Abstract: The increasing penetration of intermittent wind power affects the secure operation of power systems and leads to a requirement of robust and economic generation scheduling. This paper presents an optimal day–ahead wind–thermal generation scheduling method that considers the statistical and predicted features of wind speeds. In this method, the statistical analysis of historical wind data, which represents the local wind regime, is first implemented. Then, according to the statistical results and the predicted wind power, the spinning reserve requirements for the scheduling period are calculated. Based on the calculated spinning reserve requirements, the wind–thermal generation scheduling is finally conducted. To validate the program, a verified study is performed on a test system. Then, numerical studies to demonstrate the effectiveness of the proposed method are conducted.
International Nuclear Information System (INIS)
Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein
2017-01-01
Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Uncertainties of wind speed, solar radiation and electricity market price are considered. • Profit maximization, emission and AENS minimization are considered as objective functions. • Modified firefly algorithm is employed to solve the problem. - Abstract: Nowadays the operation of renewable energy sources and combined heat and power (CHP) units is increased in micro grids; therefore, to reach optimal performance, optimal scheduling of these units is required. In this regard, in this paper a micro grid consisting of proton exchange membrane fuel cell-combined heat and power (PEMFC-CHP), wind turbines (WT) and photovoltaic (PV) units, is modeled to determine the optimal scheduling state of these units by considering uncertain behavior of renewable energy resources. For this purpose, a scenario-based method is used for modeling the uncertainties of electrical market price, the wind speed, and solar irradiance. It should be noted that the hydrogen storage strategy is also applied in this study for PEMFC-CHP units. Market profit, total emission production, and average energy not supplied (AENS) are the objective functions considered in this paper simultaneously. Consideration of the above-mentioned objective functions converts the proposed problem to a mixed integer nonlinear programming. To solve this problem, a multi-objective firefly algorithm is used. The uncertainties of parameters convert the mixed integer nonlinear programming problem to a stochastic mixed integer nonlinear programming problem. Moreover, optimal coordinated scheduling of renewable energy resources and thermal units in micro-grids improve the value of the objective functions. Simulation results obtained from a modified 33-bus distributed network as a micro grid illustrates the effectiveness of the proposed method.
Directory of Open Access Journals (Sweden)
Abolfazl Tajzadeh-Namin
2012-01-01
Full Text Available One of the necessary actions in many organizations is to reduce the number of workers in an attempt to restructure business activities. However, layoff could have negative consequences since many employees may decide to leave since they lose their tolerance. The layoff must be accompanied with some supportive plans to reduce stress among the remaining workers and increase their commitment for long-term work. The present study of this paper considers the effects of layoff on job satisfaction and commitment among the remaining employees of a detergent producer unit. The results indicate that a good supportive program including wage increase, family support, health care plans, etc. could significantly improve employee long-term commitments and it leads to job satisfaction.
Directory of Open Access Journals (Sweden)
Sahbi Marrouchi
2014-01-01
Full Text Available Due to the continuous increase of the population and the perpetual progress of industry, the energy management presents nowadays a relevant topic that concerns researchers in electrical engineering. Indeed, in order to establish a good exploitation of the electrical grid, it is necessary to solve technical and economic problems. This can only be done through the resolution of the Unit Commitment Problem. Unit Commitment Problem allows optimizing the combination of the production units’ states and determining their production planning, in order to satisfy the expected consumption with minimal cost during a specified period which varies usually from 24 hours to one week. However, each production unit has some constraints that make this problem complex, combinatorial, and nonlinear. This paper presents a comparative study between a strategy based on hybrid gradient-genetic algorithm method and two strategies based on metaheuristic methods, fuzzy logic, and genetic algorithm, in order to predict the combinations and the unit commitment scheduling of each production unit in one side and to minimize the total production cost in the other side. To test the performance of the optimization proposed strategies, strategies have been applied to the IEEE electrical network 14 busses and the obtained results are very promising.
International Nuclear Information System (INIS)
Schenker, A.R.; Guerin, D.C.; Robey, T.H.; Rautman, C.A.; Barnard, R.W.
1995-09-01
A stochastic representation of the lithologic units and associated hydrogeologic parameters of the potential high-level nuclear waste repository are developed for use in performance-assessment calculations, including the Total-System Performance Assessment for Yucca Mountain-SNL Second Iteration (TSPA-1993). A simplified lithologic model has been developed based on the physical characteristics of the welded and nonwelded units at Yucca Mountain. Ten hydrogeologic units are developed from site-specific data (lithologic and geophysical logs and core photographs) obtained from the unsaturated and saturated zones. The three-dimensional geostatistical model of the ten hydrogeologic units is based on indicator-coding techniques and improves on the two-dimensional model developed for TSPA91. The hydrogeologic properties (statistics and probability distribution functions) are developed from the results of laboratory tests and in-situ aquifer tests or are derived through fundamental relationships. Hydrogeologic properties for matrix properties, bulk conductivities, and fractures are developed from existing site specific data. Extensive data are available for matrix porosity, bulk density, and matrix saturated conductivity. For other hydrogeologic properties, the data are minimal or nonexistent. Parameters for the properties are developed as beta probability distribution functions. For the model units without enough data for analysis, parameters are developed as analogs to existing units. A relational, analytic approach coupled with bulk conductivity parameters is used to develop fracture parameters based on the smooth-wall-parallel-plate theory. An analytic method is introduced for scaling small-core matrix properties to the hydrogeologic unit scales
New Results on a Stochastic Duel Game with Each Force Consisting of Heterogeneous Units
2013-02-01
study of duel models dates back to the 1910s, when Lanchester (1916) proposed differential equations that govern the strength of each force through time...which gave rise to what later became known as Lanchester models. A stream of works extended the Lanchester models—which are deterministic in nature...869. Kress, M. and Talmor, I. (1999). A new look at the 3:1 rule of combat through markov stochastic lanchester models. The Journal of the Operational
Energy Technology Data Exchange (ETDEWEB)
Wang, Yishen [Univ. of Washington, Seattle, WA (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Zhou, Zhi [Argonne National Lab. (ANL), Argonne, IL (United States); Liu, Cong [Argonne National Lab. (ANL), Argonne, IL (United States); Electric Reliability Council of Texas (ERCOT), Austin, TX (United States); Botterud, Audun [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-08-01
As more wind power and other renewable resources are being integrated into the electric power grid, the forecast uncertainty brings operational challenges for the power system operators. In this report, different operational strategies for uncertainty management are presented and evaluated. A comprehensive and consistent simulation framework is developed to analyze the performance of different reserve policies and scheduling techniques under uncertainty in wind power. Numerical simulations are conducted on a modified version of the IEEE 118-bus system with a 20% wind penetration level, comparing deterministic, interval, and stochastic unit commitment strategies. The results show that stochastic unit commitment provides a reliable schedule without large increases in operational costs. Moreover, decomposition techniques, such as load shift factor and Benders decomposition, can help in overcoming the computational obstacles to stochastic unit commitment and enable the use of a larger scenario set to represent forecast uncertainty. In contrast, deterministic and interval unit commitment tend to give higher system costs as more reserves are being scheduled to address forecast uncertainty. However, these approaches require a much lower computational effort Choosing a proper lower bound for the forecast uncertainty is important for balancing reliability and system operational cost in deterministic and interval unit commitment. Finally, we find that the introduction of zonal reserve requirements improves reliability, but at the expense of higher operational costs.
A Robust Optimisation Approach using CVaR for Unit Commitment in a Market with Probabilistic Offers
DEFF Research Database (Denmark)
Bukhsh, W. A.; Papakonstantinou, Athanasios; Pinson, Pierre
2016-01-01
The large scale integration of renewable energy sources (RES) challenges power system planners and operators alike as it can potentially introduce the need for costly investments in infrastructure. Furthermore, traditional market clearing mechanisms are no longer optimal due to the stochastic...... nature of RES. This paper presents a risk-aware market clearing strategy for a network with significant shares of RES. We propose an electricity market that embeds the uncertainty brought by wind power and other stochastic renewable sources by accepting probabilistic offers and use a risk measure defined...
Directory of Open Access Journals (Sweden)
Therasa Chandrasekar
2015-10-01
Full Text Available This paper provides an exposition about application of neural networks in the context of research to find out the contribution of individual job satisfiers towards work commitment. The purpose of the current study is to build a predictive model to estimate the normalized importance of individual job satisfiers towards work commitment of employees working in TVS Group, an Indian automobile company. The study is based on the tool developed by Spector (1985 and Sue Hayday (2003.The input variable of the study consists of nine independent individual job satisfiers which includes Pay, Promotion, Supervision, Benefits, Rewards, Operating procedures, Co-workers, Work-itself and Communication of Spector (1985 and dependent variable as work commitment of Sue Hayday (2003.The primary data has been collected using a closed-ended questionnaire based on simple random sampling approach. This study employed the multilayer Perceptron neural network model to envisage the level of job satisfiers towards work commitment. The result from the multilayer Perceptron neural network model displayed with four hidden layer with correct classification rate of 70% and 30% for training and testing data set. The normalized importance shows high value for coworkers, superior satisfaction and communication and which acts as most significant attributes of job satisfiers that predicts the overall work commitment of employees.
International Nuclear Information System (INIS)
Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein
2017-01-01
Highlights: •Stochastic model is proposed for coordinated scheduling of renewable energy sources. •The effect of combined heat and power is considered. •Hydrogen storage is considered for fuel cells. •Maximizing profits of micro grid is considered as objective function. •Considering the uncertainties of problem lead to profit increasing. -- Abstract: Nowadays, renewable energy sources and combined heat and power units are extremely used in micro grids, so it is necessary to schedule these units to improve the performance of the system. In this regard, a stochastic model is proposed in this paper to schedule proton exchange membrane fuel cell-combined heat and power, wind turbines, and photovoltaic units coordinately in a micro grid while considering hydrogen storage. Hydrogen storage strategy is considered for the operation of proton exchange membrane fuel cell-combined heat and power units. To consider stochastic generation of renewable energy source units in this paper, a scenario-based method is used. In this method, the uncertainties of electrical market price, the wind speed, and solar irradiance are considered. This stochastic scheduling problem is a mixed integer- nonlinear programming which considers the proposed objective function and variables of coordinated scheduling of PEMFC-CHP, wind turbines and photovoltaic units. It also considers hydrogen storage strategy and converts it to a mixed integer nonlinear problem. In this study a modified firefly algorithm is used to solve the problem. This method is examined on modified 33-bus distributed network as a MG for its performance.
Juels, Ari
The purpose of this chapter is to introduce fuzzy commitment, one of the earliest and simplest constructions geared toward cryptography over noisy data. The chapter also explores applications of fuzzy commitment to two problems in data security: (1) secure management of biometrics, with a focus on iriscodes, and (2) use of knowledge-based authentication (i.e., personal questions) for password recovery.
Scott, W; Chilcot, J; Guildford, B; Daly-Eichenhardt, A; McCracken, L M
2018-04-28
Acceptance and Commitment Therapy (ACT) has growing support for chronic pain. However, more accessible treatment delivery is needed. This study evaluated the feasibility of online ACT for patients with complex chronic pain in the United Kingdom to determine whether a larger trial is justified. Participants with chronic pain and clinically meaningful disability and distress were randomly assigned to ACT online plus specialty medical pain management, or specialty medical management alone. Participants completed questionnaires at baseline, and 3- and 9-month post-randomization. Primary feasibility outcomes included recruitment, retention and treatment completion rates. Secondary outcomes were between-groups effects on treatment outcomes and psychological flexibility. Of 139 potential participants, 63 were eligible and randomized (45% recruitment rate). Retention rates were 76-78% for follow-up assessments. Sixty-one per cent of ACT online participants completed treatment. ACT online was less often completed by employed (44%) compared to unemployed (80%) participants. Fifty-six per cent of ACT online participants rated themselves as 'much improved' or better on a global impression of change rating, compared to only 20 per cent of control participants. Three-month effects favouring ACT online were small for functioning, medication and healthcare use, committed action and decentring, medium for mood, and large for acceptance. Small-to-medium effects were maintained for functioning, healthcare use and committed action at 9 months. Online ACT for patients with chronic pain in the United Kingdom appears feasible to study in a larger efficacy trial. Some adjustments to treatment and trial procedures are warranted, particularly to enhance engagement among employed participants. This study supports the feasibility of online Acceptance and Commitment Therapy for chronic pain in the United Kingdom and a larger efficacy trial. Refinements to treatment delivery, particularly to
United States-Russian workshop on the stochastic health effects of radiation
Energy Technology Data Exchange (ETDEWEB)
Goldman, M.; Petojan, I.; Buldakov, L.A. [and others
1992-06-01
This report addresses one of the tasks agreed upon in the area of Environmental Transport and Health Effects (Working Group 7.2) of the JCCCNRS, i.e. to hold a workshop on the topic of the role of radiation dose rate effects on stochastic risks for low LET radiation. The Chernobyl Nuclear Power Plant accident in April 1986, released a very large quantity of radionuclides, and the populations were exposed primarily to low LET radiation from {sup 131}I, {sup 134,137}Cs and {sup 90}Sr. The workshop provided an opportunity for radiobiologists and epidemiologists to review and discuss the epidemiological data and the lessons from laboratory studies and reach conclusions on low level risk assessment resulting from the fundamental knowledge and theoretical models. Brief presentations were made by the attendees, and these are summarized herein. In addition many of the attendees prepared manuscripts which are included in this report. The discussion centered on a set of questions and insights into three general areas of low radiation dose rate science: epidemiological, experimental and theoretical. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
Energy Technology Data Exchange (ETDEWEB)
Wu, H.; Ela, E.; Krad, I.; Florita, A.; Zhang, J.; Hodge, B. M.; Ibanez, E.; Gao, W.
2015-03-01
This paper incorporates the stochastic day-ahead security-constrained unit commitment (DASCUC) within a multi-timescale, multi-scheduling application with commitment, dispatch, and automatic generation control. The stochastic DASCUC is solved using a progressive hedging algorithm with constrained ordinal optimization to accelerate the individual scenario solution. Sensitivity studies are performed in the RTS-96 system, and the results show how this new scheduling application would impact costs and reliability with a closer representation of timescales of system operations in practice.
Stochastic and Historical Resonances of the Unit in Physics and Psychometrics
Fisher, William P., Jr.
2011-01-01
Humphry's article, "The Role of the Unit in Physics and Psychometrics," offers fundamental clarifications of measurement concepts that Fisher hopes will find a wide audience. In particular, parameterizing discrimination while preserving statistical sufficiency will indeed provide greater flexibility in accounting "for the effects of empirical…
Unit-Sphere Multiaxial Stochastic-Strength Model Applied to Anisotropic and Composite Materials
Nemeth, Noel, N.
2013-01-01
Models that predict the failure probability of brittle materials under multiaxial loading have been developed by authors such as Batdorf, Evans, and Matsuo. These "unit-sphere" models assume that the strength-controlling flaws are randomly oriented, noninteracting planar microcracks of specified geometry but of variable size. This methodology has been extended to predict the multiaxial strength response of transversely isotropic brittle materials, including polymer matrix composites (PMCs), by considering (1) flaw-orientation anisotropy, whereby a preexisting microcrack has a higher likelihood of being oriented in one direction over another direction, and (2) critical strength, or K (sub Ic) orientation anisotropy, whereby the level of critical strength or fracture toughness for mode I crack propagation, K (sub Ic), changes with regard to the orientation of the microstructure. In this report, results from finite element analysis of a fiber-reinforced-matrix unit cell were used with the unit-sphere model to predict the biaxial strength response of a unidirectional PMC previously reported from the World-Wide Failure Exercise. Results for nuclear-grade graphite materials under biaxial loading are also shown for comparison. This effort was successful in predicting the multiaxial strength response for the chosen problems. Findings regarding stress-state interactions and failure modes also are provided.
International Nuclear Information System (INIS)
1993-09-01
Current actions by Canadian governments, non-governmental organizations, communities, and the private sector to meet domestic and international climate change commitments are reviewed. The possible impacts of climate change on Canada are discussed and Canadian greenhouse gas emissions are assessed in terms of factors such as climate, geography, land use, economic structure, and energy production and consumption. Canada's draft National Action Strategy on Global Warming provides a framework for actions to limit greenhouse gas emissions. Measures already taken include those aimed at increasing energy efficiency and energy conservation or encouraging a switch to less carbon-intensive energy sources. Other measures include information and education initiatives, regulation, research and development, and economic instruments. Actions have already been taken in the transportation, electricity generation, residential/commercial, resource/manufacturing industry, and waste management sectors. Canada is also involved in international studies and agreements to limit global greenhouse gas emissions. Four tools are used to assess progress in limiting emissions: emission inventories, climate change indicators, an emissions outlook, and case studies. The emissions outlook presented shows that energy-related greenhouse gas emissions will increase 10.6% from 1990 to 2000, reaching the equivalent of 538.2 megatonnes of CO 2 . A case study shows that current and planned measures to limit greenhouse gas emissions associated with space heating requirements in new single-family homes will reduce emissions in this area 18% from what they would otherwise be in the year 2000. 58 refs., 44 figs., 21 tabs
United States-Russian workshop on the stochastic health effects of radiation
International Nuclear Information System (INIS)
1992-01-01
In August 1988, two years after the Chernobyle accident, the United States and the Soviet Union signed an agreement to sponsor a Joint coordinating Committee on Civilian Nuclear Reactor Safety, (JCCCNRS). The Soviet Union agreed to provide some information on late effects of radiation exposures and to attempt to add some new insights into low dose and low dose rate radiation consequences. At that time, it had just been revealed that significant radiation exposures had occurred in the South Ural Mountains, associated with the early years of operation of the MAYAK nuclear complex. The need to be able to better predict the long term consequences of overexposures, such as occurred with the Chernobyl accident, was a major factor in organizing this workshop. We decided to invite a small number of experts from the Soviet Union, who had direct knowledge of the situation. A small group of American experts was invited to help in a discussion of the state of knowledge of continual low level exposure. The experts and expertise included: Aspects of bask theoretical radiobiological models, studies on experimental animals exposed to chronic or fractionated external or internal radiation, studies on populations exposed to chronic intake and continual exposures, workers exposed to low or high continual levels of radiation. The intent was to begin a dialog on the issue of a better understanding of the dose rate effect in humans. No detailed conclusions could be reached at this first interaction between out two countries, but a model was prepared which seems to support a range of what are known as low dose and dose rate effectiveness factors. A beginning of an evaluation of the role of radiation dose rate on leukemia risk was also accomplished
Stochastic volatility and stochastic leverage
DEFF Research Database (Denmark)
Veraart, Almut; Veraart, Luitgard A. M.
This paper proposes the new concept of stochastic leverage in stochastic volatility models. Stochastic leverage refers to a stochastic process which replaces the classical constant correlation parameter between the asset return and the stochastic volatility process. We provide a systematic...... treatment of stochastic leverage and propose to model the stochastic leverage effect explicitly, e.g. by means of a linear transformation of a Jacobi process. Such models are both analytically tractable and allow for a direct economic interpretation. In particular, we propose two new stochastic volatility...... models which allow for a stochastic leverage effect: the generalised Heston model and the generalised Barndorff-Nielsen & Shephard model. We investigate the impact of a stochastic leverage effect in the risk neutral world by focusing on implied volatilities generated by option prices derived from our new...
DEFF Research Database (Denmark)
Zhang, Ning; Hu, Zhaoguang; Han, Xue
2015-01-01
As a form of renewable and low-carbon energy resource, wind power is anticipated to play an essential role in the future energy structure. Whereas, its features of time mismatch with power demand and uncertainty pose barriers for the power system to utilize it effectively. Hence, a novel unit com...... system operation more eco-friendly and economical....
Energy Technology Data Exchange (ETDEWEB)
Sun, Ninghong
2013-08-08
The German Federal Government published its energy concept in September 2010 with a description of the road into the era of renewable energies. Therefore, the future renewable energy installed in Germany is expected to consist mostly of wind and solar, which are subject to intermittency of supply and significant fluctuations. The growing portion of energy generation by fluctuating sources is turning to a big challenge for the power plant unit commitment and the investment decisions as well. In this thesis, a fundamental electricity market model with combined modeling of these two aspects is developed. This model is subsequently applied to the German electricity market to investigate what kind of power plant investments are indispensable, considering the steadily increasing portion of energy generation from fluctuating sources, to ensure a reliable energy supply in a cost-effective way in the future. In addition, current energy policy in Germany regarding the use of renewable energy and nuclear energy is analyzed.
Committed dose equivalent in the practice of radiological protection
International Nuclear Information System (INIS)
Nenot, J.C.; Piechowski, J.
1985-01-01
In the case of internal exposure, the dose is not received at the moment of exposure, as happens with external exposure, since the incorporated radionuclide irradiates the various organs and tissues during the time it is present in the body. By definition, the committed dose equivalent corresponds to the received dose integrated over 50 years from the date of intake. In order to calculate it, one has to know the intake activity and the value of the committed dose equivalent per unit of intake activity. The uncertainties of the first parameter are such that the committed dose equivalent can only be regarded as an order of magnitude and not as a very accurate quantity. The use of it is justified, however, for, like the dose equivalent for external exposure, it expresses the risk of stochastic effects for the individual concerned since these effects, should they appear, would do so only after a latent period which is generally longer than the dose integration time. Moreover, the use of the committed dose equivalent offers certain advantages for dosimetric management, especially when it is simplified. A practical problem which may arise is that the annual dose limit is apparently exceeded by virtue of the fact that one is taking account, in the first year, of doses which will actually be received only in the following years. These problems are rare enough in practice to be dealt with individually in each case. (author)
Song, Lei; Zhang, Bo
2017-07-01
Nowadays, the grid faces much more challenges caused by wind power and the accessing of electric vehicles (EVs). Based on the potentiality of coordinated dispatch, a model of wind-EVs coordinated dispatch was developed. Then, A bi-level particle swarm optimization algorithm for solving the model was proposed in this paper. The application of this algorithm to 10-unit test system carried out that coordinated dispatch can benefit the power system from the following aspects: (1) Reducing operating costs; (2) Improving the utilization of wind power; (3) Stabilizing the peak-valley difference.
Stochastic Optimization Model to STudy the Operational Impacts of High Wind Penetrations in Ireland
DEFF Research Database (Denmark)
Meibom, Peter; Barth, R.; Hasche, B.
2011-01-01
A stochastic mixed integer linear optimization scheduling model minimizing system operation costs and treating load and wind power production as stochastic inputs is presented. The schedules are updated in a rolling manner as more up-to-date information becomes available. This is a fundamental...... change relative to day-ahead unit commitment approaches. The need for reserves dependent on forecast horizon and share of wind power has been estimated with a statistical model combining load and wind power forecast errors with scenarios of forced outages. The model is used to study operational impacts...
A Stochastic Operational Planning Model for Smart Power Systems
Directory of Open Access Journals (Sweden)
Sh. Jadid
2014-12-01
Full Text Available Smart Grids are result of utilizing novel technologies such as distributed energy resources, and communication technologies in power system to compensate some of its defects. Various power resources provide some benefits for operation domain however, power system operator should use a powerful methodology to manage them. Renewable resources and load add uncertainty to the problem. So, independent system operator should use a stochastic method to manage them. A Stochastic unit commitment is presented in this paper to schedule various power resources such as distributed generation units, conventional thermal generation units, wind and PV farms, and demand response resources. Demand response resources, interruptible loads, distributed generation units, and conventional thermal generation units are used to provide required reserve for compensating stochastic nature of various resources and loads. In the presented model, resources connected to distribution network can participate in wholesale market through aggregators. Moreover, a novel three-program model which can be used by aggregators is presented in this article. Loads and distributed generation can contract with aggregators by these programs. A three-bus test system and the IEEE RTS are used to illustrate usefulness of the presented model. The results show that ISO can manage the system effectively by using this model
Silva, Marcel Müller Fernandes Pereira da; Diniz-Filho, José Alexandre Felizola
2008-01-01
Despite methodological and theoretical advances in conservation genetics, data on genetic variation on broad regional spatial scales are still scarce, leading conservation planners to use general heuristic or simulation models for an integrated analysis of genetic, demographic and landscape parameters. Here, we extended previous results by evaluating spatial patterns of extinction by inbreeding depression under stochastic variation of environments for mammalian populations in 31 conservation ...
Parzen, Emanuel
1962-01-01
Well-written and accessible, this classic introduction to stochastic processes and related mathematics is appropriate for advanced undergraduate students of mathematics with a knowledge of calculus and continuous probability theory. The treatment offers examples of the wide variety of empirical phenomena for which stochastic processes provide mathematical models, and it develops the methods of probability model-building.Chapter 1 presents precise definitions of the notions of a random variable and a stochastic process and introduces the Wiener and Poisson processes. Subsequent chapters examine
Directory of Open Access Journals (Sweden)
Dongkyun Kim
2014-01-01
Full Text Available A novel approach for a Poisson cluster stochastic rainfall generator was validated in its ability to reproduce important rainfall and watershed response characteristics at 104 locations in the United States. The suggested novel approach, The Hybrid Model (THM, as compared to the traditional Poisson cluster rainfall modeling approaches, has an additional capability to account for the interannual variability of rainfall statistics. THM and a traditional approach of Poisson cluster rainfall model (modified Bartlett-Lewis rectangular pulse model were compared in their ability to reproduce the characteristics of extreme rainfall and watershed response variables such as runoff and peak flow. The results of the comparison indicate that THM generally outperforms the traditional approach in reproducing the distributions of peak rainfall, peak flow, and runoff volume. In addition, THM significantly outperformed the traditional approach in reproducing extreme rainfall by 2.3% to 66% and extreme flow values by 32% to 71%.
Directory of Open Access Journals (Sweden)
Muhammad Ali Nasir
2016-12-01
Full Text Available This study derives an optimal macroeconomic policy combination for financial sector stability in the United Kingdom by employing a New Keynesian Dynamic Stochastic General Equilibrium (NK-DSGE framework. The empirical results obtained show that disciplined fiscal and accommodative monetary policies stance is optimal for financial sector stability. Furthermore, fiscal indiscipline countered by contractionary monetary stance adversely affects financial sector stability. Financial markets, e.g. stocks and Gilts show a short-term asymmetric response to macroeconomic policy interaction and to each other. The asymmetry is a reflection of portfolio adjustment. However in the long-run, the responses to suggested optimal policy combination had homogenous effects and there was evidence of co-movement in the stock and Gilt markets.
International Nuclear Information System (INIS)
Klauder, J.R.
1983-01-01
The author provides an introductory survey to stochastic quantization in which he outlines this new approach for scalar fields, gauge fields, fermion fields, and condensed matter problems such as electrons in solids and the statistical mechanics of quantum spins. (Auth.)
STOCHASTIC ASSESSMENT OF NIGERIAN STOCHASTIC ...
African Journals Online (AJOL)
eobe
STOCHASTIC ASSESSMENT OF NIGERIAN WOOD FOR BRIDGE DECKS ... abandoned bridges with defects only in their decks in both rural and urban locations can be effectively .... which can be seen as the detection of rare physical.
Postmarket Requirements and Commitments
U.S. Department of Health & Human Services — Provides information to the public on postmarket requirements and commitments. The phrase postmarket requirements and commitments refers to studies and clinical...
Gardner, Diane L.
1992-01-01
A longitudinal, repeated-measures descriptive survey used to measure career commitment and its relationship to turnover and work performance in 320 newly employed registered nurses at one hospital found that career commitment is not a stable phenomenon. The direct association between career commitment and turnover and with job performance is weak.…
Small Business Commitment | NREL
Small Business Commitment Small Business Commitment Central to NREL's mission is our commitment to small business through a comprehensive and mature outreach program that combines proven techniques with the latest technology and best business practices. For More Information Contact Us Please email Rexann
Practical Relativistic Bit Commitment
Lunghi, T.; Kaniewski, J.; Bussières, F.; Houlmann, R.; Tomamichel, M.; Wehner, S.D.C.; Zbinden, H
2015-01-01
Bit commitment is a fundamental cryptographic primitive in which Alice wishes to commit a secret bit to Bob. Perfectly secure bit commitment between two mistrustful parties is impossible through an asynchronous exchange of quantum information. Perfect security is, however, possible when Alice and
Chang, Mou-Hsiung
2015-01-01
The classical probability theory initiated by Kolmogorov and its quantum counterpart, pioneered by von Neumann, were created at about the same time in the 1930s, but development of the quantum theory has trailed far behind. Although highly appealing, the quantum theory has a steep learning curve, requiring tools from both probability and analysis and a facility for combining the two viewpoints. This book is a systematic, self-contained account of the core of quantum probability and quantum stochastic processes for graduate students and researchers. The only assumed background is knowledge of the basic theory of Hilbert spaces, bounded linear operators, and classical Markov processes. From there, the book introduces additional tools from analysis, and then builds the quantum probability framework needed to support applications to quantum control and quantum information and communication. These include quantum noise, quantum stochastic calculus, stochastic quantum differential equations, quantum Markov semigrou...
International Nuclear Information System (INIS)
Bisognano, J.; Leemann, C.
1982-03-01
Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron
Eichhorn, Ralf; Aurell, Erik
2014-04-01
'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response
Crisan, Dan
2011-01-01
"Stochastic Analysis" aims to provide mathematical tools to describe and model high dimensional random systems. Such tools arise in the study of Stochastic Differential Equations and Stochastic Partial Differential Equations, Infinite Dimensional Stochastic Geometry, Random Media and Interacting Particle Systems, Super-processes, Stochastic Filtering, Mathematical Finance, etc. Stochastic Analysis has emerged as a core area of late 20th century Mathematics and is currently undergoing a rapid scientific development. The special volume "Stochastic Analysis 2010" provides a sa
Borodin, Andrei N
2017-01-01
This book provides a rigorous yet accessible introduction to the theory of stochastic processes. A significant part of the book is devoted to the classic theory of stochastic processes. In turn, it also presents proofs of well-known results, sometimes together with new approaches. Moreover, the book explores topics not previously covered elsewhere, such as distributions of functionals of diffusions stopped at different random times, the Brownian local time, diffusions with jumps, and an invariance principle for random walks and local times. Supported by carefully selected material, the book showcases a wealth of examples that demonstrate how to solve concrete problems by applying theoretical results. It addresses a broad range of applications, focusing on concrete computational techniques rather than on abstract theory. The content presented here is largely self-contained, making it suitable for researchers and graduate students alike.
Monte Carlo Tree Search for Continuous and Stochastic Sequential Decision Making Problems
International Nuclear Information System (INIS)
Couetoux, Adrien
2013-01-01
In this thesis, I studied sequential decision making problems, with a focus on the unit commitment problem. Traditionally solved by dynamic programming methods, this problem is still a challenge, due to its high dimension and to the sacrifices made on the accuracy of the model to apply state of the art methods. I investigated on the applicability of Monte Carlo Tree Search methods for this problem, and other problems that are single player, stochastic and continuous sequential decision making problems. In doing so, I obtained a consistent and anytime algorithm, that can easily be combined with existing strong heuristic solvers. (author)
International Nuclear Information System (INIS)
Colombino, A.; Mosiello, R.; Norelli, F.; Jorio, V.M.; Pacilio, N.
1975-01-01
A nuclear system kinetics is formulated according to a stochastic approach. The detailed probability balance equations are written for the probability of finding the mixed population of neutrons and detected neutrons, i.e. detectrons, at a given level for a given instant of time. Equations are integrated in search of a probability profile: a series of cases is analyzed through a progressive criterium. It tends to take into account an increasing number of physical processes within the chosen model. The most important contribution is that solutions interpret analytically experimental conditions of equilibrium (moise analysis) and non equilibrium (pulsed neutron measurements, source drop technique, start up procedures)
Directory of Open Access Journals (Sweden)
Romanu Ekaterini
2006-01-01
Full Text Available This article shows the similarities between Claude Debussy’s and Iannis Xenakis’ philosophy of music and work, in particular the formers Jeux and the latter’s Metastasis and the stochastic works succeeding it, which seem to proceed parallel (with no personal contact to what is perceived as the evolution of 20th century Western music. Those two composers observed the dominant (German tradition as outsiders, and negated some of its elements considered as constant or natural by "traditional" innovators (i.e. serialists: the linearity of musical texture, its form and rhythm.
Reczek, Corinne; Elliott, Sinikka; Umberson, Debra
2011-01-01
The majority of Americans will marry in their lifetimes, and for many, marriage symbolizes the transition into long-term commitment. However, many Americans cannot legally marry. This article analyzes in-depth interviews with gays and lesbians in long-term partnerships to examine union formation and commitment-making histories. Using a life course perspective that emphasizes historical and biographical contexts, the authors examine how couples conceptualize and form committed relationships despite being denied the right to marry. Although previous studies suggest that commitment ceremonies are a way to form same-sex unions, this study finds that because of their unique social, historical, and biographical relationship to marriage and ceremonies, long-term same-sex couples do not follow normative commitment-making trajectories. Instead, relationships can transition more ambiguously to committed formations without marriage, public ceremony, clear-cut act, or decision. Such an understanding of commitment making outside of marriage has implications for theorizing alternative forms of union making. PMID:21814298
48 CFR 750.7106-4 - Informal commitments.
2010-10-01
... foreign policy interests of the United States by assuring persons that they will be treated fairly and... CONTRACT MANAGEMENT EXTRAORDINARY CONTRACTUAL ACTIONS Extraordinary Contractual Actions To Protect Foreign Policy Interests of the United States 750.7106-4 Informal commitments. Informal commitments may be...
Alzheimer's: From Caring to Commitment
... Current Issue Past Issues Home Current issue contents Alzheimer's: From Caring to Commitment From Caring to Commitment ... Caring to Commitment During her sister’s battle with Alzheimer’s, Anne Murphy stayed by her side and continues ...
Lanchier, Nicolas
2017-01-01
Three coherent parts form the material covered in this text, portions of which have not been widely covered in traditional textbooks. In this coverage the reader is quickly introduced to several different topics enriched with 175 exercises which focus on real-world problems. Exercises range from the classics of probability theory to more exotic research-oriented problems based on numerical simulations. Intended for graduate students in mathematics and applied sciences, the text provides the tools and training needed to write and use programs for research purposes. The first part of the text begins with a brief review of measure theory and revisits the main concepts of probability theory, from random variables to the standard limit theorems. The second part covers traditional material on stochastic processes, including martingales, discrete-time Markov chains, Poisson processes, and continuous-time Markov chains. The theory developed is illustrated by a variety of examples surrounding applications such as the ...
Third age university, social and institucional commitment
Directory of Open Access Journals (Sweden)
Flora Moritz da Silva
2017-12-01
Full Text Available This article brings reflections on the social commitment of permanent education programs for the elderly, at the universities, in the face of their institutional commitment to the plans. It was possible to rescue the responsibility concepts, social commitment and identify the elderly in the university, within the federal legislation, through bibliographical and documentary research. There was a survey of permanent education programs with at least 20 years, in 2016. It was carried out for the elderly in the 63 Brazilian Federal, and Public Universities and 17 cases were found. Thus, nine Pro-Rectors of Extension and a Unit Director accepted to participate in interviews by Skype or telephone, in the second semester of 2016, fulfilling the objective of describing the university authorities’ vision on the type of institutional support for such programs’ operation. Although it is possible to realize their relevance to the environment and the university, the institutional commitment is still far short of what is necessary.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, the stochastic flow of mappings generated by a Feller convolution semigroup on a compact metric space is studied. This kind of flow is the generalization of superprocesses of stochastic flows and stochastic diffeomorphism induced by the strong solutions of stochastic differential equations.
Stochastic Averaging and Stochastic Extremum Seeking
Liu, Shu-Jun
2012-01-01
Stochastic Averaging and Stochastic Extremum Seeking develops methods of mathematical analysis inspired by the interest in reverse engineering and analysis of bacterial convergence by chemotaxis and to apply similar stochastic optimization techniques in other environments. The first half of the text presents significant advances in stochastic averaging theory, necessitated by the fact that existing theorems are restricted to systems with linear growth, globally exponentially stable average models, vanishing stochastic perturbations, and prevent analysis over infinite time horizon. The second half of the text introduces stochastic extremum seeking algorithms for model-free optimization of systems in real time using stochastic perturbations for estimation of their gradients. Both gradient- and Newton-based algorithms are presented, offering the user the choice between the simplicity of implementation (gradient) and the ability to achieve a known, arbitrary convergence rate (Newton). The design of algorithms...
Fundamentals of stochastic nature sciences
Klyatskin, Valery I
2017-01-01
This book addresses the processes of stochastic structure formation in two-dimensional geophysical fluid dynamics based on statistical analysis of Gaussian random fields, as well as stochastic structure formation in dynamic systems with parametric excitation of positive random fields f(r,t) described by partial differential equations. Further, the book considers two examples of stochastic structure formation in dynamic systems with parametric excitation in the presence of Gaussian pumping. In dynamic systems with parametric excitation in space and time, this type of structure formation either happens – or doesn’t! However, if it occurs in space, then this almost always happens (exponentially quickly) in individual realizations with a unit probability. In the case considered, clustering of the field f(r,t) of any nature is a general feature of dynamic fields, and one may claim that structure formation is the Law of Nature for arbitrary random fields of such type. The study clarifies the conditions under wh...
International Nuclear Information System (INIS)
Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas
2004-01-01
We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems-an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise
DEFF Research Database (Denmark)
Raastrup Kristensen, Anders; Pedersen, Michael
2016-01-01
This paper serves two purposes. First, a rereading of Douglas McGregor’s An uneasy look at performance appraisal serves to show how McGregor’s conceptualization of commitment as a question of integrating personal goals with organizational purpose has helped shape founding the modern understanding...
Employee organizational commitment
Directory of Open Access Journals (Sweden)
Radosavljević Života
2017-01-01
Full Text Available This paper shows the results of research on organizational commitment as a type of attitudes that show the identification level of employees with their organizations and their willingness to leave them. The research has been conducted with intention to determine the level of organizational commitment on the territory of Novi Sad, as well as to question whether there is a difference between certain categories of examinees for each commitment base. The research comprised 237 examinees employed in organizations on the territory of Novi Sad. Status of independent variables have gained: gender, years of working experience, educational level, working experience in one or more organizations and estimation of level of personal potentials utility. The questionnaire used is taken from the Greenberg and Baron's 'Behaviour in Organizations', p. 170, done according to set of questions by Meyer and Allen, in 1991. The data have been worked on by calculating arithmetic mean, and by application of Pearson Chi-square test. The results have shown that there is a below average level of organizational (AS=2.88, with the most intensive continual (AS=3.23, and the least intensive normative organizational dedication (AS=2.41. The gender of examinees does not represent relevant source of differences in the levels of each type of three mentioned commitment. Years of working experience and level of educational attainment represent a significant source of differences for continual (YWE: Pearson Chi-square = 30,38; df = 8; p = .000 (LEA: Pearson Chi-square = 7,381; df = 2; p = .05 and normative (YWE: Pearson Chi- square = 20,67; df = 8; p = .000 (LEA: Pearson Chi-square = 10,79; df = 2; p = .00 base of commitment. Work in one or more organizations has shown as a significant source of differences in the level of continual commitment (Pearson Chi-square = 7, 59; df = 2; p = .05. The level of affective commitment is statistically significantly related only to the estimation
Affective Commitment among Student Affairs Professionals
Boehman, Joseph
2007-01-01
Student affairs professionals in the United States were surveyed to determine the predictive value of overall job satisfaction, organizational support, organizational politics, and work/nonwork interaction on affective organizational commitment. Results indicate that a supportive work environment leads to increased affective attachment to the…
Hess, J C
1996-02-01
Most of us agree that people are our most important resource. Yet we spend a minimal amount of time learning more about human behavior, communication, and how our attitudes and behavior impact employee performance. Instead we rely on traditional methods of negative reinforcement in an attempt to control our areas of responsibility. While these methods can render some short-term success, managers and organizations that succeed during these times of change and fierce competition will be those that take the time to understand and capture the power of a committed workforce. The committed workforce is energized, not simply compliant, as a result of having basic human needs for achievement satisfied, belonging to a group, and receiving recognition for its contributions. Committed workers typically describe the manager as one who has the ability to give them a great degree of control over their area of influence. We all know that we don't change our leadership style like we change clothes. Old habits die hard. it takes a personal commitment and lots of practice to rid outselves of habits and behavior that no longer serve our departments and facilities. This commitment, however, is crucial to survival. As managers, we must cope with increasing ambiguity and uncertainty in the workplace. To survive these challenges, we must improve our interpersonal skills and ability to successfully bring out the best in others. I believe that success will continue for managers who not only increase their knowledge and technical ability, but who also inspire their workers to move forward with a collective sense of enthusiasm and purpose.
Factors influencing job satisfaction and organizational commitment.
Watson, Liana M
2008-01-01
To assess the relationship between intrinsic and extrinsic motivational factors influencing job satisfaction and the perspective of frontline medical imaging staff in acute care health care facilities in the United States. The sample consisted of 359 registered radiologic technologists who were working as staff technologists in acute care health care facilities in the United States. The results of the study suggest that satisfaction with intrinsic and extrinsic motivators influences overall satisfaction with the work environment and job and commitment to the employer.
Maximilien Brice
2001-01-01
Following the terrorist attacks recently committed in the United States of America, and according to the recommendations of the Council of the European Union, the CERN staff observed 3 minutes of silence on Friday 14 September 2001 at 12h00, as a sign of deepest sympathy for all the victims and their families, and of solidarity with the American people
Canada's commitment to nuclear technology
International Nuclear Information System (INIS)
Stewart, Murray J.
1998-01-01
This paper gives a broad update on all facets of the Canadian nuclear industry and demonstrates Canada's continuing commitment to nuclear technology. Canada has developed a global leadership position in nuclear technology for power generation, uranium production and isotope supply. This commitment is being further enhanced by successes in international markets with Candu technology, new uranium mine developments in our province of Saskatchewan, and expanding isotope capabilities including the construction of two new production reactors. Korea's economy is benefiting through collaboration with Canada's leading nuclear companies, both in Korea and Canada. These collaborations have the potential to expand considerably with the implementation of the Kyoto Framework Convention on Climate Change and the anticipated increased demand for new nuclear power generation installations in all major global markets. Much has been publicized about the situation surrounding Ontario Hydro Nuclear and its nuclear recovery program. This paper gives the background and highlights the actions within Ontario and Ontario Hydro designed to ensure the long term recovery of all twenty nuclear units in Ontario. The presentation at the conference will bring the audience completely up-to-date on recent events. (author)
National Research Council Canada - National Science Library
Khoo, Wai
1999-01-01
.... These problems model stochastic portfolio optimization problems (SPOPs) which assume deterministic unit weight, and normally distributed unit return with known mean and variance for each item type...
Sustainability Marketing Commitment
DEFF Research Database (Denmark)
Tollin, Karin; Bech Christensen, Lars
2017-01-01
sustainability in marketing, processes associated with sustainability marketing commitment, drivers of sustainability marketing at the functional level of marketing, and its organizational context. Using survey data from 269 managers in marketing, covering a broad range of industries in Sweden and Denmark, we...... took a structural modelling approach to examine construct relationships, mediation, and moderation effects. Overall, the findings show that marketing capabilities associated with the innovation of new products, services, and business models constitute a strong driver to leverage sustainability......Corporate sustainability is an important strategy and value orientation for marketing, but scarce research addresses the organizational drivers and barriers to including it in companies’ marketing strategies and processes. The purpose of this study is to determine levels of commitment to corporate...
Stochastic tools in turbulence
Lumey, John L
2012-01-01
Stochastic Tools in Turbulence discusses the available mathematical tools to describe stochastic vector fields to solve problems related to these fields. The book deals with the needs of turbulence in relation to stochastic vector fields, particularly, on three-dimensional aspects, linear problems, and stochastic model building. The text describes probability distributions and densities, including Lebesgue integration, conditional probabilities, conditional expectations, statistical independence, lack of correlation. The book also explains the significance of the moments, the properties of the
Double stochastic matrices in quantum mechanics
International Nuclear Information System (INIS)
Louck, J.D.
1997-01-01
The general set of doubly stochastic matrices of order n corresponding to ordinary nonrelativistic quantum mechanical transition probability matrices is given. Lande's discussion of the nonquantal origin of such matrices is noted. Several concrete examples are presented for elementary and composite angular momentum systems with the focus on the unitary symmetry associated with such systems in the spirit of the recent work of Bohr and Ulfbeck. Birkhoff's theorem on doubly stochastic matrices of order n is reformulated in a geometrical language suitable for application to the subset of quantum mechanical doubly stochastic matrices. Specifically, it is shown that the set of points on the unit sphere in cartesian n'-space is subjective with the set of doubly stochastic matrices of order n. The question is raised, but not answered, as to what is the subset of points of this unit sphere that correspond to the quantum mechanical transition probability matrices, and what is the symmetry group of this subset of matrices
Factors Contributing to Personal Commitment in Chinese Interethnic Couples
Directory of Open Access Journals (Sweden)
Xinmiao Zhong
2014-06-01
Full Text Available Interethnic relationships are increasingly common in many societies, yet interethnic couples have a higher divorce rate compared to intraethnic couples. Given these facts and the dearth of research, this study aimed to identify factors that contribute to couples’ commitment in interethnic relationships. This study investigated the personal commitment of Chinese interethnic couples in the United Kingdom and the United States. Specifically, whether love, dyadic adjustment and “couple cultural identity” (i.e. acculturation to the partner and couple’s similarity on individualism/collectivism would predict personal commitment and whether each variable would account for unique variance in personal commitment of the participants. Thirty-seven Chinese/non-Chinese heterosexual couples participated in the study and significant relationships between love and personal commitment, dyadic adjustment and personal commitment were found. Also, couple cultural identity was important for women’s personal commitment. Multiple regression and structural equation modelling showed that partners in interethnic relationships defined personal commitment in different ways with men emphasizing love and dyadic adjustment, and women emphasizing love and acculturation to their partner. The discovery of the importance of couple cultural identity in contributing to personal commitment, besides love and dyadic adjustment, helps researchers to gain a greater understanding of such relationships and to extend the research on interethnic relationships.
Petra, Cosmin G.; Schenk, Olaf; Lubin, Miles; Gä ertner, Klaus
2014-01-01
We present a scalable approach and implementation for solving stochastic optimization problems on high-performance computers. In this work we revisit the sparse linear algebra computations of the parallel solver PIPS with the goal of improving the shared-memory performance and decreasing the time to solution. These computations consist of solving sparse linear systems with multiple sparse right-hand sides and are needed in our Schur-complement decomposition approach to compute the contribution of each scenario to the Schur matrix. Our novel approach uses an incomplete augmented factorization implemented within the PARDISO linear solver and an outer BiCGStab iteration to efficiently absorb pivot perturbations occurring during factorization. This approach is capable of both efficiently using the cores inside a computational node and exploiting sparsity of the right-hand sides. We report on the performance of the approach on highperformance computers when solving stochastic unit commitment problems of unprecedented size (billions of variables and constraints) that arise in the optimization and control of electrical power grids. Our numerical experiments suggest that supercomputers can be efficiently used to solve power grid stochastic optimization problems with thousands of scenarios under the strict "real-time" requirements of power grid operators. To our knowledge, this has not been possible prior to the present work. © 2014 Society for Industrial and Applied Mathematics.
Ogawa, Shigeyoshi
2017-01-01
This book presents an elementary introduction to the theory of noncausal stochastic calculus that arises as a natural alternative to the standard theory of stochastic calculus founded in 1944 by Professor Kiyoshi Itô. As is generally known, Itô Calculus is essentially based on the "hypothesis of causality", asking random functions to be adapted to a natural filtration generated by Brownian motion or more generally by square integrable martingale. The intention in this book is to establish a stochastic calculus that is free from this "hypothesis of causality". To be more precise, a noncausal theory of stochastic calculus is developed in this book, based on the noncausal integral introduced by the author in 1979. After studying basic properties of the noncausal stochastic integral, various concrete problems of noncausal nature are considered, mostly concerning stochastic functional equations such as SDE, SIE, SPDE, and others, to show not only the necessity of such theory of noncausal stochastic calculus but ...
Organizational commitment of military physicians.
Demir, Cesim; Sahin, Bayram; Teke, Kadir; Ucar, Muharrem; Kursun, Olcay
2009-09-01
An individual's loyalty or bond to his or her employing organization, referred to as organizational commitment, influences various organizational outcomes such as employee motivation, job satisfaction, performance, accomplishment of organizational goals, employee turnover, and absenteeism. Therefore, as in other sectors, employee commitment is crucial also in the healthcare market. This study investigates the effects of organizational factors and personal characteristics on organizational commitment of military physicians using structural equation modeling (SEM) on a self-report, cross-sectional survey that consisted of 635 physicians working in the 2 biggest military hospitals in Turkey. The results of this study indicate that professional commitment and organizational incentives contribute positively to organizational commitment, whereas conflict with organizational goals makes a significantly negative contribution to it. These results might help develop strategies to increase employee commitment, especially in healthcare organizations, because job-related factors have been found to possess greater impact on organizational commitment than personal characteristics.
Stochastic multiobjective self-scheduling of a power producer in joint energy and reserves markets
International Nuclear Information System (INIS)
Vahidinasab, V.; Jadid, S.
2010-01-01
This paper presents a stochastic multiobjective model for self-scheduling of a power producer which participates in the day-ahead joint energy and reserves markets. The objective of a power producer is to compromise the conflicting objectives of payoff maximization and gaseous emissions minimization when committing its generation of thermal units. The proposed schedule will be used by the power producers to decide on emission quota arbitrage opportunities and for strategic bidding to the energy and reserves market. The paper analyzes a scenario-based multiobjective model in which random distributions, such as price forecasting inaccuracies as well as forced outage of generating units are modeled as scenarios tree using a combined fuzzy c-mean/Monte-Carlo simulation (FCM/MCS) method. With the above procedure the stochastic multiobjective self-scheduling problem is converted into corresponding deterministic problems. Then a multiobjective mathematical programming (MMP) approach based on ε-constraint method is implemented for each deterministic scenario. Piecewise linearized fuel and emission cost functions are applied for computational efficiency and the model is formulated as a mixed-integer programming (MIP) problem. Numerical simulations for a power producer with 21 thermal units are discussed to demonstrate the performance of the proposed approach in increasing expected payoffs by adjusting the emission quota arbitrage opportunities. (author)
Investment in different sized SMRs: Economic evaluation of stochastic scenarios by INCAS code
Energy Technology Data Exchange (ETDEWEB)
Barenghi, S.; Boarin, S.; Ricotti, M. E. [Politecnico di Milano, Dept. of Energy, CeSNEF-Nuclear Engineering Div., via La Masa 34, 20156 Milano (Italy)
2012-07-01
Small Modular LWR concepts are being developed and proposed to investors worldwide. They capitalize on operating track record of GEN II LWR, while introducing innovative design enhancements allowed by smaller size and additional benefits from the higher degree of modularization and from deployment of multiple units on the same site. (i.e. 'Economy of Multiple' paradigm) Nevertheless Small Modular Reactors pay for a dis-economy of scale that represents a relevant penalty on a capital intensive investment. Investors in the nuclear power generation industry face a very high financial risk, due to high capital commitment and exceptionally long pay-back time. Investment risk arise from uncertainty that affects scenario conditions over such a long time horizon. Risk aversion is increased by current adverse conditions of financial markets and general economic downturn, as is the case nowadays. This work investigates both the investment profitability and risk of alternative investments in a single Large Reactor or in multiple SMR of different sizes drawing information from project's Internal Rate of Return stochastic distribution. multiple SMR deployment on a single site with total power installed, equivalent to a single LR. Uncertain scenario conditions and stochastic input assumptions are included in the analysis, representing investment uncertainty and risk. Results show that, despite the combination of much larger number of stochastic variables in SMR fleets, uncertainty of project profitability is not increased, as compared to LR: SMR have features able to smooth IRR variance and control investment risk. Despite dis-economy of scale, SMR represent a limited capital commitment and a scalable investment option that meet investors' interest, even in developed and mature markets, that are traditional marketplace for LR. (authors)
Investment in different sized SMRs: Economic evaluation of stochastic scenarios by INCAS code
International Nuclear Information System (INIS)
Barenghi, S.; Boarin, S.; Ricotti, M. E.
2012-01-01
Small Modular LWR concepts are being developed and proposed to investors worldwide. They capitalize on operating track record of GEN II LWR, while introducing innovative design enhancements allowed by smaller size and additional benefits from the higher degree of modularization and from deployment of multiple units on the same site. (i.e. 'Economy of Multiple' paradigm) Nevertheless Small Modular Reactors pay for a dis-economy of scale that represents a relevant penalty on a capital intensive investment. Investors in the nuclear power generation industry face a very high financial risk, due to high capital commitment and exceptionally long pay-back time. Investment risk arise from uncertainty that affects scenario conditions over such a long time horizon. Risk aversion is increased by current adverse conditions of financial markets and general economic downturn, as is the case nowadays. This work investigates both the investment profitability and risk of alternative investments in a single Large Reactor or in multiple SMR of different sizes drawing information from project's Internal Rate of Return stochastic distribution. multiple SMR deployment on a single site with total power installed, equivalent to a single LR. Uncertain scenario conditions and stochastic input assumptions are included in the analysis, representing investment uncertainty and risk. Results show that, despite the combination of much larger number of stochastic variables in SMR fleets, uncertainty of project profitability is not increased, as compared to LR: SMR have features able to smooth IRR variance and control investment risk. Despite dis-economy of scale, SMR represent a limited capital commitment and a scalable investment option that meet investors' interest, even in developed and mature markets, that are traditional marketplace for LR. (authors)
International Nuclear Information System (INIS)
Breuer, F.; Brofferio, C.; Sacripanti, A.
1983-01-01
In the present work, with the aim of estimating more realistically the committed dose equivalent for the members of the public in the environmental impact evaluation's of nuclear plants, the authors supply a methodology for calculating the committed dose equivalents for inhalation and ingestion, and the values for fiftheen organs and sixi-three radionuclides, concerning four specific age-groups on the ground of data published by Icrp n.30 part 1, 2, 3
Stochastic Modelling Of The Repairable System
Directory of Open Access Journals (Sweden)
Andrzejczak Karol
2015-11-01
Full Text Available All reliability models consisting of random time factors form stochastic processes. In this paper we recall the definitions of the most common point processes which are used for modelling of repairable systems. Particularly this paper presents stochastic processes as examples of reliability systems for the support of the maintenance related decisions. We consider the simplest one-unit system with a negligible repair or replacement time, i.e., the unit is operating and is repaired or replaced at failure, where the time required for repair and replacement is negligible. When the repair or replacement is completed, the unit becomes as good as new and resumes operation. The stochastic modelling of recoverable systems constitutes an excellent method of supporting maintenance related decision-making processes and enables their more rational use.
Modelling Cow Behaviour Using Stochastic Automata
DEFF Research Database (Denmark)
Jónsson, Ragnar Ingi
This report covers an initial study on the modelling of cow behaviour using stochastic automata with the aim of detecting lameness. Lameness in cows is a serious problem that needs to be dealt with because it results in less profitable production units and in reduced quality of life...... for the affected livestock. By featuring training data consisting of measurements of cow activity, three different models are obtained, namely an autonomous stochastic automaton, a stochastic automaton with coinciding state and output and an autonomous stochastic automaton with coinciding state and output, all...... of which describe the cows' activity in the two regarded behavioural scenarios, non-lame and lame. Using the experimental measurement data the different behavioural relations for the two regarded behavioural scenarios are assessed. The three models comprise activity within last hour, activity within last...
A stochastic framework for the grid integration of wind power using flexible load approach
International Nuclear Information System (INIS)
Heydarian-Forushani, E.; Moghaddam, M.P.; Sheikh-El-Eslami, M.K.; Shafie-khah, M.; Catalão, J.P.S.
2014-01-01
Highlights: • This paper focuses on the potential of Demand Response Programs (DRPs) to contribute to flexibility. • A stochastic network constrained unit commitment associated with DR is presented. • DR participation levels and electricity tariffs are evaluated on providing a flexible load profile. • Novel quantitative indices for evaluating flexibility are defined to assess the success of DRPs. • DR types and customer participation levels are the main factors to modify the system load profile. - Abstract: Wind power integration has always been a key research area due to the green future power system target. However, the intermittent nature of wind power may impose some technical and economic challenges to Independent System Operators (ISOs) and increase the need for additional flexibility. Motivated by this need, this paper focuses on the potential of Demand Response Programs (DRPs) as an option to contribute to the flexible operation of power systems. On this basis, in order to consider the uncertain nature of wind power and the reality of electricity market, a Stochastic Network Constrained Unit Commitment associated with DR (SNCUCDR) is presented to schedule both generation units and responsive loads in power systems with high penetration of wind power. Afterwards, the effects of both price-based and incentive-based DRPs are evaluated, as well as DR participation levels and electricity tariffs on providing a flexible load profile and facilitating grid integration of wind power. For this reason, novel quantitative indices for evaluating flexibility are defined to assess the success of DRPs in terms of wind integration. Sensitivity studies indicate that DR types and customer participation levels are the main factors to modify the system load profile to support wind power integration
Elitism and Stochastic Dominance
Bazen, Stephen; Moyes, Patrick
2011-01-01
Stochastic dominance has typically been used with a special emphasis on risk and inequality reduction something captured by the concavity of the utility function in the expected utility model. We claim that the applicability of the stochastic dominance approach goes far beyond risk and inequality measurement provided suitable adpations be made. We apply in the paper the stochastic dominance approach to the measurment of elitism which may be considered the opposite of egalitarianism. While the...
Singular stochastic differential equations
Cherny, Alexander S
2005-01-01
The authors introduce, in this research monograph on stochastic differential equations, a class of points termed isolated singular points. Stochastic differential equations possessing such points (called singular stochastic differential equations here) arise often in theory and in applications. However, known conditions for the existence and uniqueness of a solution typically fail for such equations. The book concentrates on the study of the existence, the uniqueness, and, what is most important, on the qualitative behaviour of solutions of singular stochastic differential equations. This is done by providing a qualitative classification of isolated singular points, into 48 possible types.
Dawley, David D.; Stephens, Robert D.; Stephens, David B.
2005-01-01
This study explores the multi-dimensionality of organizational commitment of volunteer chamber of commerce board members using the Meyer and Allen (1997) scale. The effect of organizational commitment on desirable board member roles is also tested. Theory is developed by uniting past research in both organizational commitment and employee…
Insuring unit failures in electricity markets
International Nuclear Information System (INIS)
Pineda, S.; Conejo, A.J.; Carrion, M.
2010-01-01
An electric energy producer participates in futures markets in the hope of hedging the risk of trading in the pool. However, this producer is required to supply the energy associated with all its signed forward contracts even if some of its units are forced out due to unexpected failures. In this case, the producer must purchase some of the energy needed to meet its futures market commitments in the pool, which may result in high losses if the pool prices happen to be higher than the forward contract prices. To mitigate these losses, the producer can take out insurance against the forced outages of its units. Using a stochastic programming model, this paper analyzes the convenience of signing an insurance against unit failure by an electric energy producer and its impact on forward contracting decisions. Results from a realistic case study are provided and analyzed.
Work values and organizational commitment.
Kidron, A
1978-06-01
Dubin, Champoux and Porter (1975) found a strong relationship between central life interests of workers and their commitment to the organization. This paper extends their findings by investigating the relationship between work values, defined as the Protestant Ethic of the worker, and commitment to the organization. A distinction is made between moral and calculative commitment, and it is shown that work values are related more to moral than calculative involvement.
Committed equivalent organ doses and committed effective doses from intakes of radionuclides
Phipps, A W; Kendall, G M; Silk, T J; Stather, J W
1991-01-01
This report contains details of committed equivalent doses to individual organs for intakes by ingestion and inhalation of 1 mu m AMAD particles of 359 nuclides by infants aged 3 months, by children aged 1, 5, 10 and 15 years, and by adults. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on the way committed doses increase with the integration period is given in NRPB-M289. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.
24 CFR 232.510 - Commitment and commitment fee.
2010-04-01
... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE FOR NURSING HOMES, INTERMEDIATE CARE FACILITIES, BOARD AND CARE HOMES, AND... of Fire Safety Equipment Fees and Charges § 232.510 Commitment and commitment fee. (a) Issuance of...
Stochastic Methods Applied to Power System Operations with Renewable Energy: A Review
Energy Technology Data Exchange (ETDEWEB)
Zhou, Z. [Argonne National Lab. (ANL), Argonne, IL (United States); Liu, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Electric Reliability Council of Texas (ERCOT), Austin, TX (United States); Botterud, A. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-08-01
Renewable energy resources have been rapidly integrated into power systems in many parts of the world, contributing to a cleaner and more sustainable supply of electricity. Wind and solar resources also introduce new challenges for system operations and planning in terms of economics and reliability because of their variability and uncertainty. Operational strategies based on stochastic optimization have been developed recently to address these challenges. In general terms, these stochastic strategies either embed uncertainties into the scheduling formulations (e.g., the unit commitment [UC] problem) in probabilistic forms or develop more appropriate operating reserve strategies to take advantage of advanced forecasting techniques. Other approaches to address uncertainty are also proposed, where operational feasibility is ensured within an uncertainty set of forecasting intervals. In this report, a comprehensive review is conducted to present the state of the art through Spring 2015 in the area of stochastic methods applied to power system operations with high penetration of renewable energy. Chapters 1 and 2 give a brief introduction and overview of power system and electricity market operations, as well as the impact of renewable energy and how this impact is typically considered in modeling tools. Chapter 3 reviews relevant literature on operating reserves and specifically probabilistic methods to estimate the need for system reserve requirements. Chapter 4 looks at stochastic programming formulations of the UC and economic dispatch (ED) problems, highlighting benefits reported in the literature as well as recent industry developments. Chapter 5 briefly introduces alternative formulations of UC under uncertainty, such as robust, chance-constrained, and interval programming. Finally, in Chapter 6, we conclude with the main observations from our review and important directions for future work.
Redefining the merit order of stochastic generation in forward markets
DEFF Research Database (Denmark)
Morales González, Juan Miguel; Zugno, Marco; Pineda Morente, Salvador
2014-01-01
This letter proposes a new merit order for the dispatch of stochastic production in forward markets (e.g., dayahead markets). The proposed merit order considers not only the marginal cost of the stochastic generating unit, which is often very low or zero, but also the projected cost of balancing...
Stochastic analytic regularization
International Nuclear Information System (INIS)
Alfaro, J.
1984-07-01
Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)
Instantaneous stochastic perturbation theory
International Nuclear Information System (INIS)
Lüscher, Martin
2015-01-01
A form of stochastic perturbation theory is described, where the representative stochastic fields are generated instantaneously rather than through a Markov process. The correctness of the procedure is established to all orders of the expansion and for a wide class of field theories that includes all common formulations of lattice QCD.
Gottwald, G.A.; Crommelin, D.T.; Franzke, C.L.E.; Franzke, C.L.E.; O'Kane, T.J.
2017-01-01
In this chapter we review stochastic modelling methods in climate science. First we provide a conceptual framework for stochastic modelling of deterministic dynamical systems based on the Mori-Zwanzig formalism. The Mori-Zwanzig equations contain a Markov term, a memory term and a term suggestive of
Meyer, Joerg M.
2018-01-01
The contrary of stochastic independence splits up into two cases: pairs of events being favourable or being unfavourable. Examples show that both notions have quite unexpected properties, some of them being opposite to intuition. For example, transitivity does not hold. Stochastic dependence is also useful to explain cases of Simpson's paradox.
International Nuclear Information System (INIS)
Laurens, J.M.
1985-01-01
A computer code was written to model food chains in order to estimate the internal and external doses, for stochastic and non-stochastic effects, on humans (adults and infants). Results are given for 67 radionuclides, for unit concentration in water (1 Bq/L) and in atmosphere (1 Bq/m 3 )
Contexts as Shared Commitments
Directory of Open Access Journals (Sweden)
Manuel eGarcía-Carpintero
2015-12-01
Full Text Available Contemporary semantics assumes two different notions of context: one coming from Kaplan (1989, on which contexts are sets of predetermined parameters, and another originated in Stalnaker (1978, on which contexts are sets of propositions that are common ground. The latter is deservedly more popular, given its flexibility to account for context-dependent aspects of language beyond manifest indexicals, such as epistemic modals, predicates of taste, and so on and so forth; in fact, properly dealing with demonstratives (perhaps ultimately all indexicals requires that further flexibility. Even if we acknowledge Lewis (1980 point that, in a sense, Kaplanian contexts already include common ground contexts, it is better to be clear and explicit about what contexts constitutively are. Now, Stalnaker (1978, 2002, 2014 defines context-as-common-ground as a set of propositions, but recent work shows that this is not an accurate conception. The paper explains why, and provides an alternative. The main reason is that several phenomena (presuppositional treatments of pejoratives and predicates of taste, forces other than assertion require that the common ground includes non-doxastic attitudes such as appraisals, emotions, etc. Hence the common ground should not be taken to include merely contents (propositions, but those together with attitudes concerning them: shared commitments, as I will defend.
Stochastic quantization and gravity
International Nuclear Information System (INIS)
Rumpf, H.
1984-01-01
We give a preliminary account of the application of stochastic quantization to the gravitational field. We start in Section I from Nelson's formulation of quantum mechanics as Newtonian stochastic mechanics and only then introduce the Parisi-Wu stochastic quantization scheme on which all the later discussion will be based. In Section II we present a generalization of the scheme that is applicable to fields in physical (i.e. Lorentzian) space-time and treat the free linearized gravitational field in this manner. The most remarkable result of this is the noncausal propagation of conformal gravitons. Moreover the concept of stochastic gauge-fixing is introduced and a complete discussion of all the covariant gauges is given. A special symmetry relating two classes of covariant gauges is exhibited. Finally Section III contains some preliminary remarks on full nonlinear gravity. In particular we argue that in contrast to gauge fields the stochastic gravitational field cannot be transformed to a Gaussian process. (Author)
Greenwood, Priscilla E
2016-01-01
This book describes a large number of open problems in the theory of stochastic neural systems, with the aim of enticing probabilists to work on them. This includes problems arising from stochastic models of individual neurons as well as those arising from stochastic models of the activities of small and large networks of interconnected neurons. The necessary neuroscience background to these problems is outlined within the text, so readers can grasp the context in which they arise. This book will be useful for graduate students and instructors providing material and references for applying probability to stochastic neuron modeling. Methods and results are presented, but the emphasis is on questions where additional stochastic analysis may contribute neuroscience insight. An extensive bibliography is included. Dr. Priscilla E. Greenwood is a Professor Emerita in the Department of Mathematics at the University of British Columbia. Dr. Lawrence M. Ward is a Professor in the Department of Psychology and the Brain...
Organizational Climate and Teacher Commitment
Douglas, Stephen Michael
2010-01-01
This study examined the relationship of school climate and teacher commitment in elementary schools in Alabama. A total of 67 elementary schools were surveyed and 1353 teachers voluntarily participated in the study. The instruments used in this study were the Organizational Climate Index (OCI) and the Organizational Commitment Questionnaire (OCQ).…
Considerations in civil commitment of individuals with substance use disorders.
Cavaiola, Alan A; Dolan, David
2016-01-01
Several states currently have enacted laws that allow for civil commitment for individuals diagnosed with severe substance use disorders. Civil commitment or involuntary commitment refers to the legal process by which individuals with mental illness are court-ordered into inpatient and/or outpatient treatment programs. Although initially civil commitment laws were intended for individuals with severe mental illness, these statutes have been extended to cover individuals with severe substance use disorders. Much of the recent legislation allowing for civil commitment of individuals with substance use disorders has come about in response to the heroin epidemic and is designed to provide an alternative to the unrelenting progression of opioid use disorders. Civil commitment also provides an opportunity for individuals with opioid use disorders to make informed decisions regarding ongoing or continued treatment. However, civil commitment also raises concerns regarding the potential violation of 14th Amendment rights, specifically pertaining to abuses of deprivation of liberty or freedom, which are guaranteed under the 14th Amendment to the United States Constitution. This commentary examines these issues while supporting the need for effective brief civil commitment legislation in all states.
Statistical secrecy and multibit commitments
DEFF Research Database (Denmark)
Damgård, Ivan Bjerre; Pedersen, Torben P.; Pfitzmann, Birgit
1998-01-01
nothing about it. One definition is based on the L1-norm distance between probability distributions, the other on information theory. We prove that the two definitions are essentially equivalent. We also show that statistical counterparts of definitions of computational secrecy are essentially equivalent......We present and compare definitions of "statistically hiding" protocols, and we propose a novel statistically hiding commitment scheme. Informally, a protocol statistically hides a secret if a computationally unlimited adversary who conducts the protocol with the owner of the secret learns almost...... to our main definitions. Commitment schemes are an important cryptologic primitive. Their purpose is to commit one party to a certain value, while hiding this value from the other party until some later time. We present a statistically hiding commitment scheme allowing commitment to many bits...
2013-08-15
..., standards and technical regulations, sanitary and phytosanitary measures, government procurement, trade... Concerning China's Compliance With WTO Commitments AGENCY: Office of the United States Trade Representative... with its WTO commitments. SUMMARY: The interagency Trade Policy Staff Committee (TPSC) will convene a...
Gas contract portfolio management: a stochastic programming approach
International Nuclear Information System (INIS)
Haurie, A.; Smeers, Y.; Zaccour, G.
1991-01-01
This paper deals with a stochastic programming model which complements long range market simulation models generating scenarios concerning the evolution of demand and prices for gas in different market segments. Agas company has to negociate contracts with lengths going from one to twenty years. This stochastic model is designed to assess the risk associated with committing the gas production capacity of the company to these market segments. Different approaches are presented to overcome the difficulties associated with the very large size of the resulting optimization problem
Generation risk assessment in volatile conditions with wind, hydro, and natural gas units
International Nuclear Information System (INIS)
Sahin, Cem; Shahidehpour, Mohammad; Erkmen, Ismet
2012-01-01
Highlights: ► Stochastic price-based unit commitment (PBUC) for a generation company (GENCO). ► Water inflow, wind, and NG interruption uncertainties are considered. ► Diversification of assets and bilateral contracts enhance payoff and decrease financial risk. ► The utilization of NG in the risk-neutral GENCO case increases as the wind uncertainty increases. ► NG utilization is lowered by the algorithm to decrease in risk-considered case. -- Abstract: This paper studies a generating company (GENCO)’s midterm (a few months to a year) scheduling payoffs and risks in volatile operating conditions. The proposed algorithm considers the integration of intermittent wind units into a GENCO’s generation assets and coordinates the GENCO’s hourly wind generation schedule with that of natural gas (NG) units (with volatile gas prices) and hydro units (with water inflow forecast) for maximizing the GENCO’s payoff. The proposed midterm GENCO model applies market price forecasts to the risk-constrained stochastic price-based unit commitment (PBUC) for calculating the GENCO’s risk in energy and ancillary services markets. The proposed PBUC minimizes the cost of (a) NG contracts, storage, startup and shutdown, (b) startup and shutdown of cascaded hydro units, and (c) penalty for defaulting on the scheduled power delivery. Simulation results show that the diversification of generating assets including bilateral contracts (BCs) could enhance the GENCO’s midterm planning by increasing the expected payoff and decreasing the financial risk.
Sequential stochastic optimization
Cairoli, Renzo
1996-01-01
Sequential Stochastic Optimization provides mathematicians and applied researchers with a well-developed framework in which stochastic optimization problems can be formulated and solved. Offering much material that is either new or has never before appeared in book form, it lucidly presents a unified theory of optimal stopping and optimal sequential control of stochastic processes. This book has been carefully organized so that little prior knowledge of the subject is assumed; its only prerequisites are a standard graduate course in probability theory and some familiarity with discrete-paramet
Remarks on stochastic acceleration
International Nuclear Information System (INIS)
Graeff, P.
1982-12-01
Stochastic acceleration and turbulent diffusion are strong turbulence problems since no expansion parameter exists. Hence the problem of finding rigorous results is of major interest both for checking approximations and for reference models. Since we have found a way of constructing such models in the turbulent diffusion case the question of the extension to stochastic acceleration now arises. The paper offers some possibilities illustrated by the case of 'stochastic free fall' which may be particularly interesting in the context of linear response theory. (orig.)
2010-09-20
... economy of the United States constituted by the grave acts of terrorism and threats of terrorism committed by foreign terrorists, including the terrorist attacks on September 11, 2001, in New York and... security, foreign policy, and economy of the United States, the national emergency declared on September 23...
2011-09-22
... economy of the United States constituted by the grave acts of terrorism and threats of terrorism committed by foreign terrorists, including the terrorist attacks on September 11, 2001, in New York and... security, foreign policy, and economy of the United States, the national emergency declared on September 23...
Stochastic processes inference theory
Rao, Malempati M
2014-01-01
This is the revised and enlarged 2nd edition of the authors’ original text, which was intended to be a modest complement to Grenander's fundamental memoir on stochastic processes and related inference theory. The present volume gives a substantial account of regression analysis, both for stochastic processes and measures, and includes recent material on Ridge regression with some unexpected applications, for example in econometrics. The first three chapters can be used for a quarter or semester graduate course on inference on stochastic processes. The remaining chapters provide more advanced material on stochastic analysis suitable for graduate seminars and discussions, leading to dissertation or research work. In general, the book will be of interest to researchers in probability theory, mathematical statistics and electrical and information theory.
Introduction to stochastic calculus
Karandikar, Rajeeva L
2018-01-01
This book sheds new light on stochastic calculus, the branch of mathematics that is most widely applied in financial engineering and mathematical finance. The first book to introduce pathwise formulae for the stochastic integral, it provides a simple but rigorous treatment of the subject, including a range of advanced topics. The book discusses in-depth topics such as quadratic variation, Ito formula, and Emery topology. The authors briefly address continuous semi-martingales to obtain growth estimates and study solution of a stochastic differential equation (SDE) by using the technique of random time change. Later, by using Metivier–Pellumail inequality, the solutions to SDEs driven by general semi-martingales are discussed. The connection of the theory with mathematical finance is briefly discussed and the book has extensive treatment on the representation of martingales as stochastic integrals and a second fundamental theorem of asset pricing. Intended for undergraduate- and beginning graduate-level stud...
Doberkat, Ernst-Erich
2009-01-01
Combining coalgebraic reasoning, stochastic systems and logic, this volume presents the principles of coalgebraic logic from a categorical perspective. Modal logics are also discussed, including probabilistic interpretations and an analysis of Kripke models.
AESS: Accelerated Exact Stochastic Simulation
Jenkins, David D.; Peterson, Gregory D.
2011-12-01
method: The Accelerated Exact Stochastic Simulation (AESS) tool provides implementations of a wide variety of popular variations on the Gillespie method. Users can select the specific algorithm considered most appropriate. Comparisons between the methods and with other available implementations indicate that AESS provides the fastest known implementation of Gillespie's method for a variety of test models. Users may wish to execute ensembles of simulations to sweep parameters or to obtain better statistical results, so AESS supports acceleration of ensembles of simulation using parallel processing with MPI, SSE vector units on x86 processors, and/or using NVIDIA GPUs with CUDA.
Approximating Preemptive Stochastic Scheduling
Megow Nicole; Vredeveld Tjark
2009-01-01
We present constant approximative policies for preemptive stochastic scheduling. We derive policies with a guaranteed performance ratio of 2 for scheduling jobs with release dates on identical parallel machines subject to minimizing the sum of weighted completion times. Our policies as well as their analysis apply also to the recently introduced more general model of stochastic online scheduling. The performance guarantee we give matches the best result known for the corresponding determinist...
The stochastic goodwill problem
Marinelli, Carlo
2003-01-01
Stochastic control problems related to optimal advertising under uncertainty are considered. In particular, we determine the optimal strategies for the problem of maximizing the utility of goodwill at launch time and minimizing the disutility of a stream of advertising costs that extends until the launch time for some classes of stochastic perturbations of the classical Nerlove-Arrow dynamics. We also consider some generalizations such as problems with constrained budget and with discretionar...
International Nuclear Information System (INIS)
Hueffel, H.
1990-01-01
After a brief review of the BRST formalism and of the Parisi-Wu stochastic quantization method we introduce the BRST stochastic quantization scheme. It allows the second quantization of constrained Hamiltonian systems in a manifestly gauge symmetry preserving way. The examples of the relativistic particle, the spinning particle and the bosonic string are worked out in detail. The paper is closed by a discussion on the interacting field theory associated to the relativistic point particle system. 58 refs. (Author)
The dimensionality of professional commitment
Jeffrey J. Bagraim
2003-01-01
This paper examines the dimensionality of professional commitment amongst a sample of 240 South African actuaries. Data were obtained, via a mailed questionnaire, from members of the South African Actuarial Society employed in the financial services industry. Statistical analysis conducted on the data showed that the 3-component model first proposed by Meyer, Allen and Smith (1993) is appropriate for understanding professional commitment amongst South African professionals. The analysis also ...
Alcohol myopia and goal commitment
Sevincer, A. Timur; Oettingen, Gabriele
2014-01-01
According to alcohol myopia theory, acute alcohol consumption leads people to disproportionally focus on the salient rather than the peripheral aspects of a situation. We summarize various studies exploring how myopic processes resulting from acute alcohol intake affect goal commitment. After consuming alcohol student participants felt strongly committed to an important personal goal even though they had low expectations of successfully attaining the goal. However, once intoxicated participan...
Alcohol myopia and goal commitment
Directory of Open Access Journals (Sweden)
A. Timur Sevincer
2014-03-01
Full Text Available According to alcohol-myopia theory, acute alcohol consumption leads people to disproportionally focus on the salient rather than the peripheral aspects of a situation. We summarize various studies exploring how myopic processes resulting from acute alcohol intake affect goal commitment. After consuming alcohol student participants felt strongly committed to an important personal goal even though they had low expectations of successfully attaining the goal. However, once intoxicated participants were sober again (i.e., not myopic anymore they failed to act on their goal commitment. In line with alcohol-myopia theory, strong goal commitment as a result of alcohol intake was mediated by intoxicated (vs. sober participants disproportionally focusing on the desirability rather than the feasibility of their goal. Further supporting alcohol-myopia theory, when the low feasibility of attaining a particular goal was experimentally made salient (either explicitly or implicitly by subliminal priming, intoxicated participants felt less committed than those who consumed a placebo. We discuss these effects of acute alcohol intake in the context of research on the effects of chronic alcohol consumption on goal commitment.
International Nuclear Information System (INIS)
Locheed, T.
1993-01-01
The landscape has changed radically in recent years. Not too long ago, Eli Lilly and Co.'s Clinton Laboratories plant in Clinton, IN, buried its solvent storage tanks because the company's insurer required the practice. At the time, tank burial was considered the safest way to handle the solvents. One of the materials stored in those tanks, methylene chloride (or dichloromethane, DCM), was considered a virtual godsend: it was clean, safe and inexpensive. More recently, DCM has acquired a tarnished reputation and a place on the EPA's most wanted list because of its extensive use in the United States (the EPA also regulates other solvents that Lilly uses, including acetone, toluene and methanol). As well as taking aim at fugitive emissions, more properly known as equipment leaks, the Clean Air Act Amendments specify that companies cannot store such chemicals underground in single-wall tanks any longer; secondary containment is the order of the day
International Nuclear Information System (INIS)
Haran, O.; Shvarts, D.; Thieberger, R.
1998-01-01
Classical transport of neutral particles in a binary, scattering, stochastic media is discussed. It is assumed that the cross-sections of the constituent materials and their volume fractions are known. The inner structure of the media is stochastic, but there exist a statistical knowledge about the lump sizes, shapes and arrangement. The transmission through the composite media depends on the specific heterogeneous realization of the media. The current research focuses on the averaged transmission through an ensemble of realizations, frm which an effective cross-section for the media can be derived. The problem of one dimensional transport in stochastic media has been studied extensively [1]. In the one dimensional description of the problem, particles are transported along a line populated with alternating material segments of random lengths. The current work discusses transport in two-dimensional stochastic media. The phenomenon that is unique to the multi-dimensional description of the problem is obstacle bypassing. Obstacle bypassing tends to reduce the opacity of the media, thereby reducing its effective cross-section. The importance of this phenomenon depends on the manner in which the obstacles are arranged in the media. Results of transport simulations in multi-dimensional stochastic media are presented. Effective cross-sections derived from the simulations are compared against those obtained for the one-dimensional problem, and against those obtained from effective multi-dimensional models, which are partially based on a Markovian assumption
State commitment to public participation
International Nuclear Information System (INIS)
Baranski, S.C.; Serie, P.J.
1989-01-01
This paper discusses how New York's approach to developing a new low-level radioactive waste disposal facility demonstrates a commitment to responsibility for waste generated within its borders. There is a strong, legislated commitment to meeting federal milestones and starting from scratch to select a suitable site and disposal method. Equally strong is the state's commitment to meaningful public participation. A statewide program is underway, including public information and education and interactive techniques. The public participation program is fully integrated with the technical and policy activities of the New York State Low-Level Radioactive Waste Siting Commission at all levels. The program is designed to progressively tailor techniques and coverage to the steps in site and method selection, and will focus most intensively on the communities where four sites are selected for full characterization
Marketing service relationships: the role of commitment
Wetzels, M.G.M.; Ruyter, de J.C.; Birgelen, van M.
1998-01-01
As with all relationships, it is commonly agreed on that partners in business must have a high degree of commitment towards their relationship. If commitment is lacking, the relationship will soon come to an end. Affective commitment, that is commitment based on attraction between partners, is to be
Stochastic approach to microphysics
Energy Technology Data Exchange (ETDEWEB)
Aron, J.C.
1987-01-01
The presently widespread idea of ''vacuum population'', together with the quantum concept of vacuum fluctuations leads to assume a random level below that of matter. This stochastic approach starts by a reminder of the author's previous work, first on the relation of diffusion laws with the foundations of microphysics, and then on hadron spectrum. Following the latter, a random quark model is advanced; it gives to quark pairs properties similar to those of a harmonic oscillator or an elastic string, imagined as an explanation to their asymptotic freedom and their confinement. The stochastic study of such interactions as electron-nucleon, jets in e/sup +/e/sup -/ collisions, or pp -> ..pi../sup 0/ + X, gives form factors closely consistent with experiment. The conclusion is an epistemological comment (complementarity between stochastic and quantum domains, E.P.R. paradox, etc...).
Stochastic dynamics and irreversibility
Tomé, Tânia
2015-01-01
This textbook presents an exposition of stochastic dynamics and irreversibility. It comprises the principles of probability theory and the stochastic dynamics in continuous spaces, described by Langevin and Fokker-Planck equations, and in discrete spaces, described by Markov chains and master equations. Special concern is given to the study of irreversibility, both in systems that evolve to equilibrium and in nonequilibrium stationary states. Attention is also given to the study of models displaying phase transitions and critical phenomema both in thermodynamic equilibrium and out of equilibrium. These models include the linear Glauber model, the Glauber-Ising model, lattice models with absorbing states such as the contact process and those used in population dynamic and spreading of epidemic, probabilistic cellular automata, reaction-diffusion processes, random sequential adsorption and dynamic percolation. A stochastic approach to chemical reaction is also presented.The textbook is intended for students of ...
Stochastic optimization methods
Marti, Kurt
2005-01-01
Optimization problems arising in practice involve random parameters. For the computation of robust optimal solutions, i.e., optimal solutions being insensitive with respect to random parameter variations, deterministic substitute problems are needed. Based on the distribution of the random data, and using decision theoretical concepts, optimization problems under stochastic uncertainty are converted into deterministic substitute problems. Due to the occurring probabilities and expectations, approximative solution techniques must be applied. Deterministic and stochastic approximation methods and their analytical properties are provided: Taylor expansion, regression and response surface methods, probability inequalities, First Order Reliability Methods, convex approximation/deterministic descent directions/efficient points, stochastic approximation methods, differentiation of probability and mean value functions. Convergence results of the resulting iterative solution procedures are given.
International Nuclear Information System (INIS)
Rumpf, H.
1987-01-01
We begin with a naive application of the Parisi-Wu scheme to linearized gravity. This will lead into trouble as one peculiarity of the full theory, the indefiniteness of the Euclidean action, shows up already at this level. After discussing some proposals to overcome this problem, Minkowski space stochastic quantization will be introduced. This will still not result in an acceptable quantum theory of linearized gravity, as the Feynman propagator turns out to be non-causal. This defect will be remedied only after a careful analysis of general covariance in stochastic quantization has been performed. The analysis requires the notion of a metric on the manifold of metrics, and a natural candidate for this is singled out. With this a consistent stochastic quantization of Einstein gravity becomes possible. It is even possible, at least perturbatively, to return to the Euclidean regime. 25 refs. (Author)
Separable quadratic stochastic operators
International Nuclear Information System (INIS)
Rozikov, U.A.; Nazir, S.
2009-04-01
We consider quadratic stochastic operators, which are separable as a product of two linear operators. Depending on properties of these linear operators we classify the set of the separable quadratic stochastic operators: first class of constant operators, second class of linear and third class of nonlinear (separable) quadratic stochastic operators. Since the properties of operators from the first and second classes are well known, we mainly study the properties of the operators of the third class. We describe some Lyapunov functions of the operators and apply them to study ω-limit sets of the trajectories generated by the operators. We also compare our results with known results of the theory of quadratic operators and give some open problems. (author)
Stochastic cooling at Fermilab
International Nuclear Information System (INIS)
Marriner, J.
1986-08-01
The topics discussed are the stochastic cooling systems in use at Fermilab and some of the techniques that have been employed to meet the particular requirements of the anti-proton source. Stochastic cooling at Fermilab became of paramount importance about 5 years ago when the anti-proton source group at Fermilab abandoned the electron cooling ring in favor of a high flux anti-proton source which relied solely on stochastic cooling to achieve the phase space densities necessary for colliding proton and anti-proton beams. The Fermilab systems have constituted a substantial advance in the techniques of cooling including: large pickup arrays operating at microwave frequencies, extensive use of cryogenic techniques to reduce thermal noise, super-conducting notch filters, and the development of tools for controlling and for accurately phasing the system
Pledges of Commitment and Cooperation in Partnerships
Directory of Open Access Journals (Sweden)
Lachlan Deer
2016-01-01
Full Text Available We use experimental methods to investigate whether pledges of commitment can improve cooperation in endogenously-formed partnerships facing a social dilemma. Treatments vary in terms of the individual’s: (1 opportunity to commit to their partner; (2 the cost of dissolving committed partnerships; and (3 the distribution of these dissolution costs between partners. Our findings show that pledges of commitment alone can increase cooperation and welfare in committed partnerships. The introduction of relatively large and equally split costs yields similar gains. In contrast, when costs to dissolve committed partnerships fall solely on the individual choosing to break up, pledges of commitment fail to improve cooperation and welfare.
Management Commitment to Safety, Teamwork, and Hospital Worker Injuries.
McGonagle, Alyssa K; Essenmacher, Lynnette; Hamblin, Lydia; Luborsky, Mark; Upfal, Mark; Arnetz, Judith
2016-01-01
Although many studies link teamwork in health care settings to patient safety, evidence linking teamwork to hospital worker safety is lacking. This study addresses this gap by providing evidence linking teamwork perceptions in hospital workers to worker injuries, and further, finds a linkage between manager commitment to safety and teamwork. Organizational records of worker injuries and survey responses regarding management commitment to safety and teamwork from 446 hospital workers within 42 work units in a multi-site hospital system were examined. Results underscored the particular importance of teamwork on worker injuries as well as the importance of management commitment to safety as relating to teamwork. To improve worker safety, organizational leaders and unit managers should work to maintain environments wherein teamwork can thrive.
Stochastic Feedforward Control Technique
Halyo, Nesim
1990-01-01
Class of commanded trajectories modeled as stochastic process. Advanced Transport Operating Systems (ATOPS) research and development program conducted by NASA Langley Research Center aimed at developing capabilities for increases in capacities of airports, safe and accurate flight in adverse weather conditions including shear, winds, avoidance of wake vortexes, and reduced consumption of fuel. Advances in techniques for design of modern controls and increased capabilities of digital flight computers coupled with accurate guidance information from Microwave Landing System (MLS). Stochastic feedforward control technique developed within context of ATOPS program.
Markov stochasticity coordinates
International Nuclear Information System (INIS)
Eliazar, Iddo
2017-01-01
Markov dynamics constitute one of the most fundamental models of random motion between the states of a system of interest. Markov dynamics have diverse applications in many fields of science and engineering, and are particularly applicable in the context of random motion in networks. In this paper we present a two-dimensional gauging method of the randomness of Markov dynamics. The method–termed Markov Stochasticity Coordinates–is established, discussed, and exemplified. Also, the method is tweaked to quantify the stochasticity of the first-passage-times of Markov dynamics, and the socioeconomic equality and mobility in human societies.
DEFF Research Database (Denmark)
Simonsen, Maria
This thesis treats stochastic systems with switching dynamics. Models with these characteristics are studied from several perspectives. Initially in a simple framework given in the form of stochastic differential equations and, later, in an extended form which fits into the framework of sliding...... mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...
Stochastic dynamics and control
Sun, Jian-Qiao; Zaslavsky, George
2006-01-01
This book is a result of many years of author's research and teaching on random vibration and control. It was used as lecture notes for a graduate course. It provides a systematic review of theory of probability, stochastic processes, and stochastic calculus. The feedback control is also reviewed in the book. Random vibration analyses of SDOF, MDOF and continuous structural systems are presented in a pedagogical order. The application of the random vibration theory to reliability and fatigue analysis is also discussed. Recent research results on fatigue analysis of non-Gaussian stress proc
CSIR Research Space (South Africa)
Roux, FS
2013-09-01
Full Text Available Roux Presented at the International Conference on Correlation Optics 2013 Chernivtsi, Ukraine 18-20 September 2013 CSIR National Laser Centre, Pretoria, South Africa – p. 1/24 Contents ⊲ Defining Stochastic Singular Optics (SSO) ⊲ Tools of Stochastic... of vortices: topological charge ±1 (higher order are unstable). Positive and negative vortex densities np(x, y, z) and nn(x, y, z) ⊲ Vortex density: V = np + nn ⊲ Topological charge density: T = np − nn – p. 4/24 Subfields of SSO ⊲ Homogeneous, normally...
Foundations of stochastic analysis
Rao, M M; Lukacs, E
1981-01-01
Foundations of Stochastic Analysis deals with the foundations of the theory of Kolmogorov and Bochner and its impact on the growth of stochastic analysis. Topics covered range from conditional expectations and probabilities to projective and direct limits, as well as martingales and likelihood ratios. Abstract martingales and their applications are also discussed. Comprised of five chapters, this volume begins with an overview of the basic Kolmogorov-Bochner theorem, followed by a discussion on conditional expectations and probabilities containing several characterizations of operators and mea
Markov stochasticity coordinates
Energy Technology Data Exchange (ETDEWEB)
Eliazar, Iddo, E-mail: iddo.eliazar@intel.com
2017-01-15
Markov dynamics constitute one of the most fundamental models of random motion between the states of a system of interest. Markov dynamics have diverse applications in many fields of science and engineering, and are particularly applicable in the context of random motion in networks. In this paper we present a two-dimensional gauging method of the randomness of Markov dynamics. The method–termed Markov Stochasticity Coordinates–is established, discussed, and exemplified. Also, the method is tweaked to quantify the stochasticity of the first-passage-times of Markov dynamics, and the socioeconomic equality and mobility in human societies.
Stochastic models, estimation, and control
Maybeck, Peter S
1982-01-01
This volume builds upon the foundations set in Volumes 1 and 2. Chapter 13 introduces the basic concepts of stochastic control and dynamic programming as the fundamental means of synthesizing optimal stochastic control laws.
Pledges of commitment and cooperation in partnerships
Lachlan Deer; Ralph-C. Bayer
2015-01-01
We use experimental methods to investigate whether pledges of commitment can improve cooperation in endogenously-formed partnerships facing a social dilemma. Treatments vary in terms of the individual's: (1) opportunity to commit to their partner; (2) the cost of dissolving committed partnerships; and (3) the distribution of these dissolution costs between partners. Our findings show that pledges of commitment alone can increase cooperation and welfare in committed partnerships. The introduct...
Stochastic quantisation: theme and variation
International Nuclear Information System (INIS)
Klauder, J.R.; Kyoto Univ.
1987-01-01
The paper on stochastic quantisation is a contribution to the book commemorating the sixtieth birthday of E.S. Fradkin. Stochastic quantisation reformulates Euclidean quantum field theory in the language of Langevin equations. The generalised free field is discussed from the viewpoint of stochastic quantisation. An artificial family of highly singular model theories wherein the space-time derivatives are dropped altogether is also examined. Finally a modified form of stochastic quantisation is considered. (U.K.)
Stochastic Modeling and Analysis of Power System with Renewable Generation
DEFF Research Database (Denmark)
Chen, Peiyuan
Unlike traditional fossil-fuel based power generation, renewable generation such as wind power relies on uncontrollable prime sources such as wind speed. Wind speed varies stochastically, which to a large extent determines the stochastic behavior of power generation from wind farms...... that such a stochastic model can be used to simulate the effect of load management on the load duration curve. As CHP units are turned on and off by regulating power, CHP generation has discrete output and thus can be modeled by a transition matrix based discrete Markov chain. As the CHP generation has a strong diurnal...
Quality Improvement with Trustee Commitment.
Chaffee, Ellen Earle; Seymour, Daniel
1991-01-01
Total Quality Management is a comprehensive system for developing organizationwide participation in planning for and implementing continuous improvement in critical processes. In colleges, trustees can be central to the success of the method through their commitment and the development of supportive policy and procedures. (MSE)
Commitment Profiles and Employee Turnover
Stanley, Laura; Vandenberghe, Christian; Vandenberg, Robert; Bentein, Kathleen
2013-01-01
We examined how affective (AC), normative (NC), perceived sacrifice (PS), and few alternatives (FA) commitments combine to form profiles and determine turnover intention and turnover. We theorized that three mechanisms account for how profiles operate, i.e., the degree to which membership is internally regulated, the perceived desirability and…
When a Patient Commits Suicide.
Marshall, Karol A.
1980-01-01
Suicide is a tragic and upsetting event which sometimes occurs when a person is in some form of therapy. This paper advocates a process after a patient commits suicide which allows for a thorough and orderly working through of the event by involved treatment personnel. (Author)
Cheat Sensitive Quantum Bit Commitment
Hardy, Lucien; Kent, Adrian
1999-01-01
We define cheat sensitive cryptographic protocols between mistrustful parties as protocols which guarantee that, if either cheats, the other has some nonzero probability of detecting the cheating. We give an example of an unconditionally secure cheat sensitive non-relativistic bit commitment protocol which uses quantum information to implement a task which is classically impossible; we also describe a simple relativistic protocol.
Cheat sensitive quantum bit commitment.
Hardy, Lucien; Kent, Adrian
2004-04-16
We define cheat sensitive cryptographic protocols between mistrustful parties as protocols which guarantee that, if either cheats, the other has some nonzero probability of detecting the cheating. We describe an unconditionally secure cheat sensitive nonrelativistic bit commitment protocol which uses quantum information to implement a task which is classically impossible; we also describe a simple relativistic protocol.
Parenting--Challenge and Commitment
Luckey, Eleanore Braun
1973-01-01
This is a revised version of the National Council on Family Relations Presidential address delivered November 3, 1972, Portland Oregon. This address concerned the new constitution and reorganization of N.C.F.R. and a plea for reexamination of the membership's commitment to family issues. (JC)
Idiosyncratic Deals and Organizational Commitment
Ng, Thomas W. H.; Feldman, Daniel C.
2010-01-01
This article examines the relationship between idiosyncratic deals and organizational commitment. In particular, it examines how two individual differences which reflect self-worth (core self-evaluations and age) moderate that relationship. We predicted that employees with feelings of high self-worth will expect and will feel entitled to these…
Physical Education Teachers' Organizational Commitment
Demir, Hayri
2013-01-01
The aim of this study was to determine physical education teachers' organizational commitment levels. The sample consisted of 204 physical education teachers working in the city center of Konya in the 2011 to 2012 academic year. The respondents were randomly selected in this research. Data collected for this research by using the Scale for…
Faculty Organizational Commitment and Citizenship
Lawrence, Janet; Ott, Molly; Bell, Alli
2012-01-01
Building on a theoretical framework that links characteristics of individuals and their work settings to organizational commitment (OC) and citizenship behavior, this study considers why faculty may be disengaging from institutional service. Analyses of survey data collected from a state system of higher education suggest that job characteristics,…
24-Hour Relativistic Bit Commitment.
Verbanis, Ephanielle; Martin, Anthony; Houlmann, Raphaël; Boso, Gianluca; Bussières, Félix; Zbinden, Hugo
2016-09-30
Bit commitment is a fundamental cryptographic primitive in which a party wishes to commit a secret bit to another party. Perfect security between mistrustful parties is unfortunately impossible to achieve through the asynchronous exchange of classical and quantum messages. Perfect security can nonetheless be achieved if each party splits into two agents exchanging classical information at times and locations satisfying strict relativistic constraints. A relativistic multiround protocol to achieve this was previously proposed and used to implement a 2-millisecond commitment time. Much longer durations were initially thought to be insecure, but recent theoretical progress showed that this is not so. In this Letter, we report on the implementation of a 24-hour bit commitment solely based on timed high-speed optical communication and fast data processing, with all agents located within the city of Geneva. This duration is more than 6 orders of magnitude longer than before, and we argue that it could be extended to one year and allow much more flexibility on the locations of the agents. Our implementation offers a practical and viable solution for use in applications such as digital signatures, secure voting and honesty-preserving auctions.
Stochastic quantization of Proca field
International Nuclear Information System (INIS)
Lim, S.C.
1981-03-01
We discuss the complications that arise in the application of Nelson's stochastic quantization scheme to classical Proca field. One consistent way to obtain spin-one massive stochastic field is given. It is found that the result of Guerra et al on the connection between ground state stochastic field and the corresponding Euclidean-Markov field extends to the spin-one case. (author)
Stochastic Estimation via Polynomial Chaos
2015-10-01
AFRL-RW-EG-TR-2015-108 Stochastic Estimation via Polynomial Chaos Douglas V. Nance Air Force Research...COVERED (From - To) 20-04-2015 – 07-08-2015 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Stochastic Estimation via Polynomial Chaos ...This expository report discusses fundamental aspects of the polynomial chaos method for representing the properties of second order stochastic
Saman Chehrazi; Mehrdad Hoseini Shakib; Mohammad Hosein Askari Azad
2014-01-01
This paper presents a casual structure model between emotional intelligence and organizational citizenship behavior by using organizational commitment as mediator variable. The study is accomplished among 324 employees of united bus company in city of Tehran, Iran. Using structural equation modeling, the study has confirmed that emotional intelligence influenced on organizational citizenship behavior and commitment. The study also confirms that organizational commitment influenced on organiza...
Fryer, Ashley-Kay; Tucker, Anita L; Singer, Sara J
Recent literature suggests that middle manager affective commitment (emotional attachment, identification, and involvement) to an improvement program may influence implementation success. However, less is known about the interplay between middle manager affective commitment and frontline worker commitment, another important driver of implementation success. We contribute to this research by surveying middle managers who directly manage frontline workers on nursing units. We assess how middle manager affective commitment is related to their perceptions of implementation success and whether their perceptions of frontline worker support mediate this relationship. We also test whether a set of organizational support factors foster middle manager affective commitment. We adapt survey measures of manager affective commitment to our research context of hospitals. We surveyed 67 nurse managers from 19 U.S. hospitals. We use hierarchical linear regression to assess relationships among middle manager affective commitment to their units' falls reduction program and their perceptions of three constructs related to the program: frontline worker support, organizational support, and implementation success. Middle manager affective commitment to their unit's falls reduction program is positively associated with their perception of implementation success. This relationship is mediated by their perception of frontline worker support for the falls program. Moreover, middle managers' affective commitment to their unit's falls program mediates the relationship between perceived organizational support for the program and perceived implementation success. We, through this research, offer an important contribution by providing empirical support of factors that may influence successful implementation of an improvement program: middle manager affective commitment, frontline worker support, and organizational support for an improvement program. Increasing levels of middle manager affective
Energy Technology Data Exchange (ETDEWEB)
Tollestrup, A.V.; Dugan, G
1983-12-01
Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck equation; calculation of constants in the Fokker-Planck equation; and beam feedback. (GHT)
Schrager, D.F.
2006-01-01
We propose a new model for stochastic mortality. The model is based on the literature on affine term structure models. It satisfies three important requirements for application in practice: analytical tractibility, clear interpretation of the factors and compatibility with financial option pricing
Composite stochastic processes
Kampen, N.G. van
Certain problems in physics and chemistry lead to the definition of a class of stochastic processes. Although they are not Markovian they can be treated explicitly to some extent. In particular, the probability distribution for large times can be found. It is shown to obey a master equation. This
Entropy Production in Stochastics
Directory of Open Access Journals (Sweden)
Demetris Koutsoyiannis
2017-10-01
Full Text Available While the modern definition of entropy is genuinely probabilistic, in entropy production the classical thermodynamic definition, as in heat transfer, is typically used. Here we explore the concept of entropy production within stochastics and, particularly, two forms of entropy production in logarithmic time, unconditionally (EPLT or conditionally on the past and present having been observed (CEPLT. We study the theoretical properties of both forms, in general and in application to a broad set of stochastic processes. A main question investigated, related to model identification and fitting from data, is how to estimate the entropy production from a time series. It turns out that there is a link of the EPLT with the climacogram, and of the CEPLT with two additional tools introduced here, namely the differenced climacogram and the climacospectrum. In particular, EPLT and CEPLT are related to slopes of log-log plots of these tools, with the asymptotic slopes at the tails being most important as they justify the emergence of scaling laws of second-order characteristics of stochastic processes. As a real-world application, we use an extraordinary long time series of turbulent velocity and show how a parsimonious stochastic model can be identified and fitted using the tools developed.
Stochastic modelling of turbulence
DEFF Research Database (Denmark)
Sørensen, Emil Hedevang Lohse
previously been shown to be closely connected to the energy dissipation. The incorporation of the small scale dynamics into the spatial model opens the door to a fully fledged stochastic model of turbulence. Concerning the interaction of wind and wind turbine, a new method is proposed to extract wind turbine...
Research in Stochastic Processes.
1982-10-31
Office of Scientific Research Grant AFOSR F49620 82 C 0009 Period: 1 Noveber 1981 through 31 October 1982 Title: Research in Stochastic Processes Co...STA4ATIS CAMBANIS The work briefly described here was developed in connection with problems arising from and related to the statistical comunication
Stochastic Control - External Models
DEFF Research Database (Denmark)
Poulsen, Niels Kjølstad
2005-01-01
This note is devoted to control of stochastic systems described in discrete time. We are concerned with external descriptions or transfer function model, where we have a dynamic model for the input output relation only (i.e.. no direct internal information). The methods are based on LTI systems...
Stochastic nonlinear beam equations
Czech Academy of Sciences Publication Activity Database
Brzezniak, Z.; Maslowski, Bohdan; Seidler, Jan
2005-01-01
Roč. 132, č. 1 (2005), s. 119-149 ISSN 0178-8051 R&D Projects: GA ČR(CZ) GA201/01/1197 Institutional research plan: CEZ:AV0Z10190503 Keywords : stochastic beam equation * stability Subject RIV: BA - General Mathematics Impact factor: 0.896, year: 2005
Effects of Gender on Engineering Career Commitment
Barker, Anne M.
Engineering has been one of the most difficult fields for 'women to enter and in which to succeed. Although the percentage of female engineers has Increased, women are still seriously underrcpresented in the workforce. This study examined the effect offender on career commitment, success, satisfaction, and involvement in engineering, and the effect of personality and work environment on these variables. Alumni from an engineering school in the northeastern United States were surveyed. The questionnaire was analyzed using statistical and descriptive methods to determine relationships among these variables. Women's commitment scores were lower than men's when controlled for other variables, including satisfaction and involvement. Men had longer tenure as engineers than women, even when controlled for year of graduation, professional engineering status, and number of children. Women did not leave engineering in different proportions than men, but they did earn significantly less despite controlling for year of graduation and number of hours worked weekly. Some gender differences in workplace experience were also found, including having colleagues act protectively, being mistaken for secretaries, and seeing men progress faster in their careers than equally qualified women.
Stochastic processes in cell biology
Bressloff, Paul C
2014-01-01
This book develops the theory of continuous and discrete stochastic processes within the context of cell biology. A wide range of biological topics are covered including normal and anomalous diffusion in complex cellular environments, stochastic ion channels and excitable systems, stochastic calcium signaling, molecular motors, intracellular transport, signal transduction, bacterial chemotaxis, robustness in gene networks, genetic switches and oscillators, cell polarization, polymerization, cellular length control, and branching processes. The book also provides a pedagogical introduction to the theory of stochastic process – Fokker Planck equations, stochastic differential equations, master equations and jump Markov processes, diffusion approximations and the system size expansion, first passage time problems, stochastic hybrid systems, reaction-diffusion equations, exclusion processes, WKB methods, martingales and branching processes, stochastic calculus, and numerical methods. This text is primarily...
World Tourism Organization - 30 years of commitment to environmental protection
Energy Technology Data Exchange (ETDEWEB)
Shackleford, P
1985-01-01
The paper traces 30 years of commitment to environmental values of tourism by the intergovernmental World Tourism Organization. Such commitment was almost unfashionable in the 1950s but gradually what began as an article of faith was vindicated by results of market research showing that the protection, enhancement and improvement of man's physical and human environment were among the fundamental requirements for the harmonious development of tourism. The establishment of the United Nations Environmental Program at last gave WTO a partner with the necessary authority with which the world body could walk towards mutually agreed goals.
World Tourism Organization - 30 years of commitment to environmental protection
Energy Technology Data Exchange (ETDEWEB)
Shackleford, P.
1985-01-01
The paper traces 30 years of commitment to environmental values of tourism by the intergovernmental World Tourism Organization. Such commitment was almost unfashionable in the 1950s but gradually what began as an article of faith was vindicated by results of market research showing that the protection, enhancement and improvement of man's physical and human environment were among the fundamental requirements for the harmonious development of tourism. The establishment of the United Nations Environmental Program at last gave WTO a partner with the necessary authority with which the world body could walk towards mutually agreed goals.
Committed effective doses at various times after intakes of radionuclides
Phipps, A W; Kendall, G M; Silk, T J; Stather, J W
1991-01-01
This report contains details of committed effective doses at nine times after intake from intakes by ingestion and inhalation of 1 mu 1 AMAD particles by adults. Data are given for various chemical forms of 359 nuclides. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on committed equivalent doses to organs is given in NRPB-M288. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.
Petersen, Connie L.; Zettle, Robert D.
2009-01-01
Inpatients involuntarily committed to a chemical dependency unit and exhibiting a co-occurring depressive disorder received either individual sessions of acceptance and commitment therapy (ACT) or treatment as usual (TAU) within the context of an ongoing 12-step program. Results indicated significant, but equivalent, reductions in levels of…
Boards: Independent and Committed Directors?
Christophe Volonté
2011-01-01
Regulators, proxy advisors and shareholders are regularly calling for independent directors. However, at the same time, independent directors commonly engage in numerous outside activities potentially reducing their time and commitment with the particular firm. Using Tobin's Q as an approximation of market valuation and controlling for endogeneity, our empirical analysis reveals that neither is independence positively related to firm performance nor are outside activities negatively related t...
The dimensionality of professional commitment
Directory of Open Access Journals (Sweden)
Jeffrey J. Bagraim
2003-10-01
Full Text Available This paper examines the dimensionality of professional commitment amongst a sample of 240 South African actuaries. Data were obtained, via a mailed questionnaire, from members of the South African Actuarial Society employed in the financial services industry. Statistical analysis conducted on the data showed that the 3-component model first proposed by Meyer, Allen and Smith (1993 is appropriate for understanding professional commitment amongst South African professionals. The analysis also showed that South African actuaries are highly committed to their profession. Opsomming Hierdie artikel ondersoek die dimensionaliteit van professionele toewyding by ‘n steekproef van 240 Suid-Afrikaanse aktuarisse. Die data is verkry deur ‘n posvraelys aan lede van die Suid-Afrikaanse Aktuariële Vereniging wat in die finansiële dienstesektor werksaam was. Statistiese ontledings wat uitgevoer is op die data dui aan dat die driekomponentmodel, aanvanklik voorgestel deur Meyer, Allen en Smith (1993, geskik is om professionele toewyding by Suid-Afrikaanse beroepslui te verstaan. Die ontleding dui verder aan dat Suid-Afrikaanse aktuarisse hoogs toegewyd is aan hulle professie.
Directory of Open Access Journals (Sweden)
Saman Chehrazi
2014-06-01
Full Text Available This paper presents a casual structure model between emotional intelligence and organizational citizenship behavior by using organizational commitment as mediator variable. The study is accomplished among 324 employees of united bus company in city of Tehran, Iran. Using structural equation modeling, the study has confirmed that emotional intelligence influenced on organizational citizenship behavior and commitment. The study also confirms that organizational commitment influenced on organizational citizenship behavior. Finally, the study has confirmed that there were significant relationships between emotional intelligence and its dimensions with organizational citizenship behavior and organizational commitment of employees.
Stochastic calculus and applications
Cohen, Samuel N
2015-01-01
Completely revised and greatly expanded, the new edition of this text takes readers who have been exposed to only basic courses in analysis through the modern general theory of random processes and stochastic integrals as used by systems theorists, electronic engineers and, more recently, those working in quantitative and mathematical finance. Building upon the original release of this title, this text will be of great interest to research mathematicians and graduate students working in those fields, as well as quants in the finance industry. New features of this edition include: End of chapter exercises; New chapters on basic measure theory and Backward SDEs; Reworked proofs, examples and explanatory material; Increased focus on motivating the mathematics; Extensive topical index. "Such a self-contained and complete exposition of stochastic calculus and applications fills an existing gap in the literature. The book can be recommended for first-year graduate studies. It will be useful for all who intend to wo...
Some illustrations of stochasticity
International Nuclear Information System (INIS)
Laslett, L.J.
1977-01-01
A complex, and apparently stochastic, character frequently can be seen to occur in the solutions to simple Hamiltonian problems. Such behavior is of interest, and potentially of importance, to designers of particle accelerators--as well as to workers in other fields of physics and related disciplines. Even a slow development of disorder in the motion of particles in a circular accelerator or storage ring could be troublesome, because a practical design requires the beam particles to remain confined in an orderly manner within a narrow beam tube for literally tens of billions of revolutions. The material presented is primarily the result of computer calculations made to investigate the occurrence of ''stochasticity,'' and is organized in a manner similar to that adopted for presentation at a 1974 accelerator conference
Stochastic ice stream dynamics.
Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca
2016-08-09
Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.
Fractional Stochastic Field Theory
Honkonen, Juha
2018-02-01
Models describing evolution of physical, chemical, biological, social and financial processes are often formulated as differential equations with the understanding that they are large-scale equations for averages of quantities describing intrinsically random processes. Explicit account of randomness may lead to significant changes in the asymptotic behaviour (anomalous scaling) in such models especially in low spatial dimensions, which in many cases may be captured with the use of the renormalization group. Anomalous scaling and memory effects may also be introduced with the use of fractional derivatives and fractional noise. Construction of renormalized stochastic field theory with fractional derivatives and fractional noise in the underlying stochastic differential equations and master equations and the interplay between fluctuation-induced and built-in anomalous scaling behaviour is reviewed and discussed.
Essentials of stochastic processes
Durrett, Richard
2016-01-01
Building upon the previous editions, this textbook is a first course in stochastic processes taken by undergraduate and graduate students (MS and PhD students from math, statistics, economics, computer science, engineering, and finance departments) who have had a course in probability theory. It covers Markov chains in discrete and continuous time, Poisson processes, renewal processes, martingales, and option pricing. One can only learn a subject by seeing it in action, so there are a large number of examples and more than 300 carefully chosen exercises to deepen the reader’s understanding. Drawing from teaching experience and student feedback, there are many new examples and problems with solutions that use TI-83 to eliminate the tedious details of solving linear equations by hand, and the collection of exercises is much improved, with many more biological examples. Originally included in previous editions, material too advanced for this first course in stochastic processes has been eliminated while treatm...
Dynamic stochastic optimization
Ermoliev, Yuri; Pflug, Georg
2004-01-01
Uncertainties and changes are pervasive characteristics of modern systems involving interactions between humans, economics, nature and technology. These systems are often too complex to allow for precise evaluations and, as a result, the lack of proper management (control) may create significant risks. In order to develop robust strategies we need approaches which explic itly deal with uncertainties, risks and changing conditions. One rather general approach is to characterize (explicitly or implicitly) uncertainties by objec tive or subjective probabilities (measures of confidence or belief). This leads us to stochastic optimization problems which can rarely be solved by using the standard deterministic optimization and optimal control methods. In the stochastic optimization the accent is on problems with a large number of deci sion and random variables, and consequently the focus ofattention is directed to efficient solution procedures rather than to (analytical) closed-form solu tions. Objective an...
Stochastic porous media equations
Barbu, Viorel; Röckner, Michael
2016-01-01
Focusing on stochastic porous media equations, this book places an emphasis on existence theorems, asymptotic behavior and ergodic properties of the associated transition semigroup. Stochastic perturbations of the porous media equation have reviously been considered by physicists, but rigorous mathematical existence results have only recently been found. The porous media equation models a number of different physical phenomena, including the flow of an ideal gas and the diffusion of a compressible fluid through porous media, and also thermal propagation in plasma and plasma radiation. Another important application is to a model of the standard self-organized criticality process, called the "sand-pile model" or the "Bak-Tang-Wiesenfeld model". The book will be of interest to PhD students and researchers in mathematics, physics and biology.
Stochastic stacking without filters
International Nuclear Information System (INIS)
Johnson, R.P.; Marriner, J.
1982-12-01
The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10 8 per sec is achieved with a 4 to 8 GHz bandwidth
Multistage stochastic optimization
Pflug, Georg Ch
2014-01-01
Multistage stochastic optimization problems appear in many ways in finance, insurance, energy production and trading, logistics and transportation, among other areas. They describe decision situations under uncertainty and with a longer planning horizon. This book contains a comprehensive treatment of today’s state of the art in multistage stochastic optimization. It covers the mathematical backgrounds of approximation theory as well as numerous practical algorithms and examples for the generation and handling of scenario trees. A special emphasis is put on estimation and bounding of the modeling error using novel distance concepts, on time consistency and the role of model ambiguity in the decision process. An extensive treatment of examples from electricity production, asset liability management and inventory control concludes the book
Dynamics of stochastic systems
Klyatskin, Valery I
2005-01-01
Fluctuating parameters appear in a variety of physical systems and phenomena. They typically come either as random forces/sources, or advecting velocities, or media (material) parameters, like refraction index, conductivity, diffusivity, etc. The well known example of Brownian particle suspended in fluid and subjected to random molecular bombardment laid the foundation for modern stochastic calculus and statistical physics. Other important examples include turbulent transport and diffusion of particle-tracers (pollutants), or continuous densities (''''oil slicks''''), wave propagation and scattering in randomly inhomogeneous media, for instance light or sound propagating in the turbulent atmosphere.Such models naturally render to statistical description, where the input parameters and solutions are expressed by random processes and fields.The fundamental problem of stochastic dynamics is to identify the essential characteristics of system (its state and evolution), and relate those to the input parameters of ...
Job insecurity, organisational commitment and work engagement ...
African Journals Online (AJOL)
understanding the concept of job insecurity as represented by two core ... commitment as a unidimensional construct based on employees' emotional .... outcomes such as increased job satisfaction, organisational commitment, motivation.
Antecedents and Consequences of Affective Commitment
Bloemer, J.M.M.; Odekerken-Schröder, G.J.
2003-01-01
The primary objective of this study is to assess the impact of three psychological antecedents (position involvement, volitional choice and informational complexity) on affective commitment in a financial service setting. Furthermore, this study addresses the consequences of affective commitment on
Logic for specifying partially observable stochastic domains
CSIR Research Space (South Africa)
Rens, G
2011-07-01
Full Text Available to place it back on the floor. In situations where the oil-can is full, the robot gets 5 units of reward for grabbing the can, and it gets 10 units for a drink action. Otherwise, the robot gets no rewards. Rewards motivate an agent to behave as desired... with notions of probability. It will be shown how stochastic domains can be specified, including new kinds of axioms dealing with perception and a frame solution for the proposed logic. 1 Introduction and Motivation In the physical real world...
Identifiability in stochastic models
1992-01-01
The problem of identifiability is basic to all statistical methods and data analysis, occurring in such diverse areas as Reliability Theory, Survival Analysis, and Econometrics, where stochastic modeling is widely used. Mathematics dealing with identifiability per se is closely related to the so-called branch of ""characterization problems"" in Probability Theory. This book brings together relevant material on identifiability as it occurs in these diverse fields.
Stochastic split determinant algorithms
International Nuclear Information System (INIS)
Horvatha, Ivan
2000-01-01
I propose a large class of stochastic Markov processes associated with probability distributions analogous to that of lattice gauge theory with dynamical fermions. The construction incorporates the idea of approximate spectral split of the determinant through local loop action, and the idea of treating the infrared part of the split through explicit diagonalizations. I suggest that exact algorithms of practical relevance might be based on Markov processes so constructed
Zhang, Ning; Zhou, Zhi-min; Su, Chen-ting; Zhou, Nan
2013-11-01
Although previous research indicates that participation in a brand community may foster consumer loyalty to the brand in question, research has seldom examined the mediating effect of community commitment on brand commitment. Drawing from the typologies of organizational commitment, we divide community commitment into three components: continuance community commitment (continuance CC), affective community commitment (affective CC), and normative community commitment (normative CC). We then assess the mediating role of brand attachment in the relationship between these three components and brand commitment. We test the hypotheses using a sample of online mobile phone brand communities in China. The empirical results reveal that brand attachment exerts an indirect (but not mediated) effect on the relationship between continuance CC and brand commitment and on the relationship between normative CC and brand commitment. We also find that it exerts a partial mediating effect on the relationship between affective CC and brand commitment. The findings contribute to the branding literature and have important implications for brand community management.
Stochasticity Modeling in Memristors
Naous, Rawan; Al-Shedivat, Maruan; Salama, Khaled N.
2015-01-01
Diverse models have been proposed over the past years to explain the exhibiting behavior of memristors, the fourth fundamental circuit element. The models varied in complexity ranging from a description of physical mechanisms to a more generalized mathematical modeling. Nonetheless, stochasticity, a widespread observed phenomenon, has been immensely overlooked from the modeling perspective. This inherent variability within the operation of the memristor is a vital feature for the integration of this nonlinear device into the stochastic electronics realm of study. In this paper, experimentally observed innate stochasticity is modeled in a circuit compatible format. The model proposed is generic and could be incorporated into variants of threshold-based memristor models in which apparent variations in the output hysteresis convey the switching threshold shift. Further application as a noise injection alternative paves the way for novel approaches in the fields of neuromorphic engineering circuits design. On the other hand, extra caution needs to be paid to variability intolerant digital designs based on non-deterministic memristor logic.
Stochasticity Modeling in Memristors
Naous, Rawan
2015-10-26
Diverse models have been proposed over the past years to explain the exhibiting behavior of memristors, the fourth fundamental circuit element. The models varied in complexity ranging from a description of physical mechanisms to a more generalized mathematical modeling. Nonetheless, stochasticity, a widespread observed phenomenon, has been immensely overlooked from the modeling perspective. This inherent variability within the operation of the memristor is a vital feature for the integration of this nonlinear device into the stochastic electronics realm of study. In this paper, experimentally observed innate stochasticity is modeled in a circuit compatible format. The model proposed is generic and could be incorporated into variants of threshold-based memristor models in which apparent variations in the output hysteresis convey the switching threshold shift. Further application as a noise injection alternative paves the way for novel approaches in the fields of neuromorphic engineering circuits design. On the other hand, extra caution needs to be paid to variability intolerant digital designs based on non-deterministic memristor logic.
Stochastic quantization of instantons
International Nuclear Information System (INIS)
Grandati, Y.; Berard, A.; Grange, P.
1996-01-01
The method of Parisi and Wu to quantize classical fields is applied to instanton solutions var-phi I of euclidian non-linear theory in one dimension. The solution var-phi var-epsilon of the corresponding Langevin equation is built through a singular perturbative expansion in var-epsilon=h 1/2 in the frame of the center of the mass of the instanton, where the difference var-phi var-epsilon -var-phi I carries only fluctuations of the instanton form. The relevance of the method is shown for the stochastic K dV equation with uniform noise in space: the exact solution usually obtained by the inverse scattering method is retrieved easily by the singular expansion. A general diagrammatic representation of the solution is then established which makes a thorough use of regrouping properties of stochastic diagrams derived in scalar field theory. Averaging over the noise and in the limit of infinite stochastic time, the authors obtain explicit expressions for the first two orders in var-epsilon of the pertrubed instanton of its Green function. Specializing to the Sine-Gordon and var-phi 4 models, the first anaharmonic correction is obtained analytically. The calculation is carried to second order for the var-phi 4 model, showing good convergence. 21 refs., 5 fig
24 CFR 203.7 - Commitment process.
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Commitment process. 203.7 Section 203.7 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... Insurance, and Commitments § 203.7 Commitment process. For single family mortgage programs that are not...
Commitment among Arab Adolescents in Israel.
Ben-Ari, Adital Tirosh; Azaiza, Faisal
1998-01-01
Examines 662 Arab adolescents' commitments to their own self-development, family, Arab people, and village along with the order in which these commitments are structured. Reveals that the two prevalent patterns of adolescent commitment, individualistic and collectivistic, demonstrate the adolescents' struggle with these value systems and the…
24 CFR 200.47 - Firm commitments.
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... Eligibility Requirements for Existing Projects Commitment Applications § 200.47 Firm commitments. A valid firm...
Building commitment in a sports class
DEFF Research Database (Denmark)
Olesen, Jesper; Nielsen, Jens Christian
The literature has traditionally considered commitment as an individual characteristic or condition of the individual. This means that one is inclined to think that it is those who have commitment who have the opportunity to become excellent performers within their sport. But what if commitment...
Organizational and Client Commitment among Contracted Employees
Coyle-Shapiro, Jacqueline A-M.; Morrow, Paula C.
2006-01-01
This study examines affective commitment to employing and client organizations among long-term contracted employees, a new and growing employment classification. Drawing on organizational commitment and social exchange literatures, we propose two categories of antecedents of employee commitment to client organizations. We tested our hypotheses…
Alternative Approaches to Technical Efficiency Estimation in the Stochastic Frontier Model
Acquah, H. de-Graft; Onumah, E. E.
2014-01-01
Estimating the stochastic frontier model and calculating technical efficiency of decision making units are of great importance in applied production economic works. This paper estimates technical efficiency from the stochastic frontier model using Jondrow, and Battese and Coelli approaches. In order to compare alternative methods, simulated data with sample sizes of 60 and 200 are generated from stochastic frontier model commonly applied to agricultural firms. Simulated data is employed to co...
Stochastic and non-stochastic effects - a conceptual analysis
International Nuclear Information System (INIS)
Karhausen, L.R.
1980-01-01
The attempt to divide radiation effects into stochastic and non-stochastic effects is discussed. It is argued that radiation or toxicological effects are contingently related to radiation or chemical exposure. Biological effects in general can be described by general laws but these laws never represent a necessary connection. Actually stochastic effects express contingent, or empirical, connections while non-stochastic effects represent semantic and non-factual connections. These two expressions stem from two different levels of discourse. The consequence of this analysis for radiation biology and radiation protection is discussed. (author)
MONTE CARLO SIMULATION OF MULTIFOCAL STOCHASTIC SCANNING SYSTEM
Directory of Open Access Journals (Sweden)
LIXIN LIU
2014-01-01
Full Text Available Multifocal multiphoton microscopy (MMM has greatly improved the utilization of excitation light and imaging speed due to parallel multiphoton excitation of the samples and simultaneous detection of the signals, which allows it to perform three-dimensional fast fluorescence imaging. Stochastic scanning can provide continuous, uniform and high-speed excitation of the sample, which makes it a suitable scanning scheme for MMM. In this paper, the graphical programming language — LabVIEW is used to achieve stochastic scanning of the two-dimensional galvo scanners by using white noise signals to control the x and y mirrors independently. Moreover, the stochastic scanning process is simulated by using Monte Carlo method. Our results show that MMM can avoid oversampling or subsampling in the scanning area and meet the requirements of uniform sampling by stochastically scanning the individual units of the N × N foci array. Therefore, continuous and uniform scanning in the whole field of view is implemented.
A retrodictive stochastic simulation algorithm
International Nuclear Information System (INIS)
Vaughan, T.G.; Drummond, P.D.; Drummond, A.J.
2010-01-01
In this paper we describe a simple method for inferring the initial states of systems evolving stochastically according to master equations, given knowledge of the final states. This is achieved through the use of a retrodictive stochastic simulation algorithm which complements the usual predictive stochastic simulation approach. We demonstrate the utility of this new algorithm by applying it to example problems, including the derivation of likely ancestral states of a gene sequence given a Markovian model of genetic mutation.
Stochastic processes and quantum theory
International Nuclear Information System (INIS)
Klauder, J.R.
1975-01-01
The author analyses a variety of stochastic processes, namely real time diffusion phenomena, which are analogues of imaginary time quantum theory and convariant imaginary time quantum field theory. He elaborates some standard properties involving probability measures and stochastic variables and considers a simple class of examples. Finally he develops the fact that certain stochastic theories actually exhibit divergences that simulate those of covariant quantum field theory and presents examples of both renormaizable and unrenormalizable behavior. (V.J.C.)
DEFF Research Database (Denmark)
Koch, Alexander; Nafziger, Julia
People often overcome self-control problems by promising to reward themselves for accomplishing a task. Such strategies based on self-administered rewards however require the person to believe that she would indeed deny herself the reward if she should fail to achieve the desired outcome. Drawing...... on Koszegi and Rabin's (2006) model of endogenous reference point formation, we show how a rational forward-looking individual can achieve such internal commitment. But our results also demonstrate the limitations of self regulation based on self-rewards....
Koch, Alexander K.; Nafziger, Julia
2009-01-01
Self-administered rewards are ubiquitous. They serve as incentives for personal accomplish¬ments and are widely recommended as tools for overcoming self-control problems. However, it seems puzzling why self-rewards can work: the prospect of a reward has a motivating force only if the threat of self-denial of the reward after low performance is credible. We explain how a rational forward-looking individual may achieve commitment to self-rewards, by applying Köszegi and Rabin's (2006) model of ...
Our Commitment to Bioenergy Sustainability
Energy Technology Data Exchange (ETDEWEB)
None
2015-06-18
The U.S. Department of Energy’s Bioenergy Technologies Office (BETO) is committed to developing the resources, technologies, and systems needed to support a thriving bioenergy industry that protects natural resources and ad- vances environmental, economic, and social benefits. BETO’s Sustainability Technology Area proactively identifies and addresses issues that affect the scale-up potential, public acceptance, and long-term viability of advanced bioenergy systems; as a result, the area is critical to achieving BETO’s overall goals.
INPO and the industry: a commitment to excellence
International Nuclear Information System (INIS)
Colvin, J.F.
1985-01-01
Utilities in the United States have undergone major changes in their attitudes and methods of operating nuclear stations in the 6 yr since the accident at Three Mile Island. These changes reflect a strong commitment by the US utility industry to excellence in nuclear plant operations. Fundamental in this commitment was the formation of the Institute of Nuclear Power Operations (INPO), an organization created by the industry in the United States to serve as a focus and catalyst for these changes. With membership in INPO, nuclear utilities make a commitment to strive for excellence in the construction and operation of their nuclear plants. INPO has programs to help utilities in their efforts to achieve excellence. The most visible are the INPO evaluation programs. By the end of 1985, INPO will have evaluated most operating plants at least four times. Construction project evaluations are also being conducted. Twenty-one construction evaluations will have been conducted by the end of the year. Through each of its programs, INPO seeks to promote excellence and to help those operating and building nuclear plants in their commitment to excellence
Stochastic Analysis with Financial Applications
Kohatsu-Higa, Arturo; Sheu, Shuenn-Jyi
2011-01-01
Stochastic analysis has a variety of applications to biological systems as well as physical and engineering problems, and its applications to finance and insurance have bloomed exponentially in recent times. The goal of this book is to present a broad overview of the range of applications of stochastic analysis and some of its recent theoretical developments. This includes numerical simulation, error analysis, parameter estimation, as well as control and robustness properties for stochastic equations. This book also covers the areas of backward stochastic differential equations via the (non-li
Energy Technology Data Exchange (ETDEWEB)
Hardwick, Robert J.; Vennin, Vincent; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Byrnes, Christian T.; Torrado, Jesús, E-mail: robert.hardwick@port.ac.uk, E-mail: vincent.vennin@port.ac.uk, E-mail: c.byrnes@sussex.ac.uk, E-mail: jesus.torrado@sussex.ac.uk, E-mail: david.wands@port.ac.uk [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)
2017-10-01
We study the stochastic distribution of spectator fields predicted in different slow-roll inflation backgrounds. Spectator fields have a negligible energy density during inflation but may play an important dynamical role later, even giving rise to primordial density perturbations within our observational horizon today. During de-Sitter expansion there is an equilibrium solution for the spectator field which is often used to estimate the stochastic distribution during slow-roll inflation. However slow roll only requires that the Hubble rate varies slowly compared to the Hubble time, while the time taken for the stochastic distribution to evolve to the de-Sitter equilibrium solution can be much longer than a Hubble time. We study both chaotic (monomial) and plateau inflaton potentials, with quadratic, quartic and axionic spectator fields. We give an adiabaticity condition for the spectator field distribution to relax to the de-Sitter equilibrium, and find that the de-Sitter approximation is never a reliable estimate for the typical distribution at the end of inflation for a quadratic spectator during monomial inflation. The existence of an adiabatic regime at early times can erase the dependence on initial conditions of the final distribution of field values. In these cases, spectator fields acquire sub-Planckian expectation values. Otherwise spectator fields may acquire much larger field displacements than suggested by the de-Sitter equilibrium solution. We quantify the information about initial conditions that can be obtained from the final field distribution. Our results may have important consequences for the viability of spectator models for the origin of structure, such as the simplest curvaton models.
International Nuclear Information System (INIS)
Hardwick, Robert J.; Vennin, Vincent; Wands, David; Byrnes, Christian T.; Torrado, Jesús
2017-01-01
We study the stochastic distribution of spectator fields predicted in different slow-roll inflation backgrounds. Spectator fields have a negligible energy density during inflation but may play an important dynamical role later, even giving rise to primordial density perturbations within our observational horizon today. During de-Sitter expansion there is an equilibrium solution for the spectator field which is often used to estimate the stochastic distribution during slow-roll inflation. However slow roll only requires that the Hubble rate varies slowly compared to the Hubble time, while the time taken for the stochastic distribution to evolve to the de-Sitter equilibrium solution can be much longer than a Hubble time. We study both chaotic (monomial) and plateau inflaton potentials, with quadratic, quartic and axionic spectator fields. We give an adiabaticity condition for the spectator field distribution to relax to the de-Sitter equilibrium, and find that the de-Sitter approximation is never a reliable estimate for the typical distribution at the end of inflation for a quadratic spectator during monomial inflation. The existence of an adiabatic regime at early times can erase the dependence on initial conditions of the final distribution of field values. In these cases, spectator fields acquire sub-Planckian expectation values. Otherwise spectator fields may acquire much larger field displacements than suggested by the de-Sitter equilibrium solution. We quantify the information about initial conditions that can be obtained from the final field distribution. Our results may have important consequences for the viability of spectator models for the origin of structure, such as the simplest curvaton models.
Portfolio Optimization with Stochastic Dividends and Stochastic Volatility
Varga, Katherine Yvonne
2015-01-01
We consider an optimal investment-consumption portfolio optimization model in which an investor receives stochastic dividends. As a first problem, we allow the drift of stock price to be a bounded function. Next, we consider a stochastic volatility model. In each problem, we use the dynamic programming method to derive the Hamilton-Jacobi-Bellman…
Stochastic ontogenetic growth model
West, B. J.; West, D.
2012-02-01
An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.
Stochastic calculus in physics
International Nuclear Information System (INIS)
Fox, R.F.
1987-01-01
The relationship of Ito-Stratonovich stochastic calculus to studies of weakly colored noise is explained. A functional calculus approach is used to obtain an effective Fokker-Planck equation for the weakly colored noise regime. In a smooth limit, this representation produces the Stratonovich version of the Ito-Stratonovich calculus for white noise. It also provides an approach to steady state behavior for strongly colored noise. Numerical simulation algorithms are explored, and a novel suggestion is made for efficient and accurate simulation of white noise equations
The stochastic quality calculus
DEFF Research Database (Denmark)
Zeng, Kebin; Nielson, Flemming; Nielson, Hanne Riis
2014-01-01
We introduce the Stochastic Quality Calculus in order to model and reason about distributed processes that rely on each other in order to achieve their overall behaviour. The calculus supports broadcast communication in a truly concurrent setting. Generally distributed delays are associated...... with the outputs and at the same time the inputs impose constraints on the waiting times. Consequently, the expected inputs may not be available when needed and therefore the calculus allows to express the absence of data.The communication delays are expressed by general distributions and the resulting semantics...
Stochastic conditional intensity processes
DEFF Research Database (Denmark)
Bauwens, Luc; Hautsch, Nikolaus
2006-01-01
model allows for a wide range of (cross-)autocorrelation structures in multivariate point processes. The model is estimated by simulated maximum likelihood (SML) using the efficient importance sampling (EIS) technique. By modeling price intensities based on NYSE trading, we provide significant evidence......In this article, we introduce the so-called stochastic conditional intensity (SCI) model by extending Russell’s (1999) autoregressive conditional intensity (ACI) model by a latent common dynamic factor that jointly drives the individual intensity components. We show by simulations that the proposed...... for a joint latent factor and show that its inclusion allows for an improved and more parsimonious specification of the multivariate intensity process...
Stochastic cooling for beginners
International Nuclear Information System (INIS)
Moehl, D.
1984-01-01
These two lectures have been prepared to give a simple introduction to the principles. In Part I we try to explain stochastic cooling using the time-domain picture which starts from the pulse response of the system. In Part II the discussion is repeated, looking more closely at the frequency-domain response. An attempt is made to familiarize the beginners with some of the elementary cooling equations, from the 'single particle case' up to equations which describe the evolution of the particle distribution. (orig.)
Trajectory averaging for stochastic approximation MCMC algorithms
Liang, Faming
2010-01-01
to the stochastic approximation Monte Carlo algorithm [Liang, Liu and Carroll J. Amer. Statist. Assoc. 102 (2007) 305-320]. The application of the trajectory averaging estimator to other stochastic approximationMCMC algorithms, for example, a stochastic
Outcomes of patients who commit suicide by burning.
Castana, O; Kourakos, P; Moutafidis, M; Stampolidis, N; Triantafyllou, V; Pallantzas, Ath; Filippa, E; Alexandropoulos, C
2013-03-31
Cases in which people use fire when attempting or committing suicide are not common but nevertheless constitute a cause of admission to burns units worldwide. Usually these people are suffering from stress and have been diagnosed as mentally ill. Schizophrenia, depression, and personality disorders are the most frequently diagnosed conditions. The psychological problems appear to have been overlooked by the family or not to have been presented to them. The aim of this study is to present the clinical features, characteristics, and outcomes of patients burned during a suicide attempt. The role of the psychiatrist is important, starting in the emergency room. The incidence of patients committing self-injury by burning appears to be higher in women burn patients. Deceased patients usually have a larger extent of burns and a higher incidence of other injuries and require more surgical procedures and longer hospitalization times. The problems for burn unit staff and qualified psychiatric care are discussed.
Outcomes of patients who commit suicide by burning
Castana, O.; Kourakos, P.; Moutafidis, M.; Stampolidis, N.; Triantafyllou, V.; Pallantzas, Ath.; Filippa, E.; Alexandropoulos, C.
2013-01-01
Summary Cases in which people use fire when attempting or committing suicide are not common but nevertheless constitute a cause of admission to burns units worldwide. Usually these people are suffering from stress and have been diagnosed as mentally ill. Schizophrenia, depression, and personality disorders are the most frequently diagnosed conditions. The psychological problems appear to have been overlooked by the family or not to have been presented to them. The aim of this study is to present the clinical features, characteristics, and outcomes of patients burned during a suicide attempt. The role of the psychiatrist is important, starting in the emergency room. The incidence of patients committing self-injury by burning appears to be higher in women burn patients. Deceased patients usually have a larger extent of burns and a higher incidence of other injuries and require more surgical procedures and longer hospitalization times. The problems for burn unit staff and qualified psychiatric care are discussed. PMID:23966897
Short-term hydropower production planning by stochastic programming
DEFF Research Database (Denmark)
Fleten, Stein-Erik; Kristoffersen, Trine
2008-01-01
-term production planning a matter of spatial distribution among the reservoirs of the plant. Day-ahead market prices and reservoir inflows are, however, uncertain beyond the current operation day and water must be allocated among the reservoirs in order to strike a balance between current profits and expected......Within the framework of multi-stage mixed-integer linear stochastic programming we develop a short-term production plan for a price-taking hydropower plant operating under uncertainty. Current production must comply with the day-ahead commitments of the previous day which makes short...
Stochastic line motion and stochastic flux conservation for nonideal hydromagnetic models
International Nuclear Information System (INIS)
Eyink, Gregory L.
2009-01-01
We prove that smooth solutions of nonideal (viscous and resistive) incompressible magnetohydrodynamic (MHD) equations satisfy a stochastic law of flux conservation. This property implies that the magnetic flux through a surface is equal to the average of the magnetic fluxes through an ensemble of surfaces advected backward in time by the plasma velocity perturbed with a random white noise. Our result is an analog of the well-known Alfven theorem of ideal MHD and is valid for any value of the magnetic Prandtl number. A second stochastic conservation law is shown to hold at unit Prandtl number, a random version of the generalized Kelvin theorem derived by Bekenstein and Oron for ideal MHD. These stochastic conservation laws are not only shown to be consequences of the nonideal MHD equations but are proved in fact to be equivalent to those equations. We derive similar results for two more refined hydromagnetic models, Hall MHD and the two-fluid plasma model, still assuming incompressible velocities and isotropic transport coefficients. Finally, we use these results to discuss briefly the infinite-Reynolds-number limit of hydromagnetic turbulence and to support the conjecture that flux conservation remains stochastic in that limit.
Stochastic Blind Motion Deblurring
Xiao, Lei
2015-05-13
Blind motion deblurring from a single image is a highly under-constrained problem with many degenerate solutions. A good approximation of the intrinsic image can therefore only be obtained with the help of prior information in the form of (often non-convex) regularization terms for both the intrinsic image and the kernel. While the best choice of image priors is still a topic of ongoing investigation, this research is made more complicated by the fact that historically each new prior requires the development of a custom optimization method. In this paper, we develop a stochastic optimization method for blind deconvolution. Since this stochastic solver does not require the explicit computation of the gradient of the objective function and uses only efficient local evaluation of the objective, new priors can be implemented and tested very quickly. We demonstrate that this framework, in combination with different image priors produces results with PSNR values that match or exceed the results obtained by much more complex state-of-the-art blind motion deblurring algorithms.
Schilstra, Maria J; Martin, Stephen R
2009-01-01
Stochastic simulations may be used to describe changes with time of a reaction system in a way that explicitly accounts for the fact that molecules show a significant degree of randomness in their dynamic behavior. The stochastic approach is almost invariably used when small numbers of molecules or molecular assemblies are involved because this randomness leads to significant deviations from the predictions of the conventional deterministic (or continuous) approach to the simulation of biochemical kinetics. Advances in computational methods over the three decades that have elapsed since the publication of Daniel Gillespie's seminal paper in 1977 (J. Phys. Chem. 81, 2340-2361) have allowed researchers to produce highly sophisticated models of complex biological systems. However, these models are frequently highly specific for the particular application and their description often involves mathematical treatments inaccessible to the nonspecialist. For anyone completely new to the field to apply such techniques in their own work might seem at first sight to be a rather intimidating prospect. However, the fundamental principles underlying the approach are in essence rather simple, and the aim of this article is to provide an entry point to the field for a newcomer. It focuses mainly on these general principles, both kinetic and computational, which tend to be not particularly well covered in specialist literature, and shows that interesting information may even be obtained using very simple operations in a conventional spreadsheet.
AA, stochastic precooling pickup
CERN PhotoLab
1980-01-01
The freshly injected antiprotons were subjected to fast stochastic "precooling". In this picture of a precooling pickup, the injection orbit is to the left, the stack orbit to the far right. After several seconds of precooling with the system's kickers (in momentum and in the vertical plane), the precooled antiprotons were transferred, by means of RF, to the stack tail, where they were subjected to further stochastic cooling in momentum and in both transverse planes, until they ended up, deeply cooled, in the stack core. During precooling, a shutter near the central orbit shielded the pickups from the signals emanating from the stack-core, whilst the stack-core was shielded from the violent action of the precooling kickers by a shutter on these. All shutters were opened briefly during transfer of the precooled antiprotons to the stack tail. Here, the shutter is not yet mounted. Precooling pickups and kickers had the same design, except that the kickers had cooling circuits and the pickups had none. Peering th...
Behavioral Stochastic Resonance
Freund, Jan A.; Schimansky-Geier, Lutz; Beisner, Beatrix; Neiman, Alexander; Russell, David F.; Yakusheva, Tatyana; Moss, Frank
2001-03-01
Zooplankton emit weak electric fields into the surrounding water that originate from their own muscular activities associated with swimming and feeding. Juvenile paddlefish prey upon single zooplankton by detecting and tracking these weak electric signatures. The passive electric sense in the fish is provided by an elaborate array of electroreceptors, Ampullae Lorenzini, spread over the surface of an elongated rostrum. We have previously shown that the fish use stochastic resonance to enhance prey capture near the detection threshold of their sensory system. But stochastic resonance requires an external source of electrical noise in order to function. The required noise can be provided by a swarm of plankton, for example Daphnia. Thus juvenile paddlefish can detect and attack single Daphnia as outliers in the vicinity of the swarm by making use of noise from the swarm itself. From the power spectral density of the noise plus the weak signal from a single Daphnia we calculate the signal-to-noise ratio and the Fisher information at the surface of the paddlefish's rostrum. The results predict a specific attack pattern for the paddlefish that appears to be experimentally testable.
International Nuclear Information System (INIS)
Akroyd, Duane; Legg, Jeff; Jackowski, Melissa B.; Adams, Robert D.
2009-01-01
The purpose of this study was to examine the impact of selected organizational factors and the leadership behavior of supervisors on radiation therapists' commitment to their organizations. The population for this study consists of all full time clinical radiation therapists registered by the American Registry of Radiologic Technologists (ARRT) in the United States. A random sample of 800 radiation therapists was obtained from the ARRT for this study. Questionnaires were mailed to all participants and measured organizational variables; managerial leadership variable and three components of organizational commitment (affective, continuance and normative). It was determined that organizational support, and leadership behavior of supervisors each had a significant and positive affect on normative and affective commitment of radiation therapists and each of the models predicted over 40% of the variance in radiation therapists organizational commitment. This study examined radiation therapists' commitment to their organizations and found that affective (emotional attachment to the organization) and normative (feelings of obligation to the organization) commitments were more important than continuance commitment (awareness of the costs of leaving the organization). This study can help radiation oncology administrators and physicians to understand the values their radiation therapy employees hold that are predictive of their commitment to the organization. A crucial result of the study is the importance of the perceived support of the organization and the leadership skills of managers/supervisors on radiation therapists' commitment to the organization.
Energy Technology Data Exchange (ETDEWEB)
Akroyd, Duane [Department of Adult and Community College Education, College of Education, Campus Box 7801, North Carolina State University, Raleigh, NC 27695 (United States)], E-mail: duane_akroyd@ncsu.edu; Legg, Jeff [Department of Radiologic Sciences, Virginia Commonwealth University, Richmond, VA 23284 (United States); Jackowski, Melissa B. [Division of Radiologic Sciences, University of North Carolina School of Medicine 27599 (United States); Adams, Robert D. [Department of Radiation Oncology, University of North Carolina School of Medicine 27599 (United States)
2009-05-15
The purpose of this study was to examine the impact of selected organizational factors and the leadership behavior of supervisors on radiation therapists' commitment to their organizations. The population for this study consists of all full time clinical radiation therapists registered by the American Registry of Radiologic Technologists (ARRT) in the United States. A random sample of 800 radiation therapists was obtained from the ARRT for this study. Questionnaires were mailed to all participants and measured organizational variables; managerial leadership variable and three components of organizational commitment (affective, continuance and normative). It was determined that organizational support, and leadership behavior of supervisors each had a significant and positive affect on normative and affective commitment of radiation therapists and each of the models predicted over 40% of the variance in radiation therapists organizational commitment. This study examined radiation therapists' commitment to their organizations and found that affective (emotional attachment to the organization) and normative (feelings of obligation to the organization) commitments were more important than continuance commitment (awareness of the costs of leaving the organization). This study can help radiation oncology administrators and physicians to understand the values their radiation therapy employees hold that are predictive of their commitment to the organization. A crucial result of the study is the importance of the perceived support of the organization and the leadership skills of managers/supervisors on radiation therapists' commitment to the organization.
An empirical investigation on relationship between social capital and organizational commitment
Directory of Open Access Journals (Sweden)
Ali Alikhani
2014-02-01
Full Text Available This paper presents an empirical investigation to study the relationship between social capital and organizational commitment. The study considers the relationship between social capital with three components of organizational commitment; namely, affective commitment, continuous and normative commitment. The study has been applied among a sample of 292 regular employees who worked for an Iranian bank located in city of Tehran, Iran. The implementation of Pearson correlation has indicated that there were positive and meaningful relationships between social capital and affective commitment (r = 0.197, Sig. = 0.01, continuous (r = 0.308, Sig. = 0.01 and normative commitment (r = 0.423, Sig. = 0.01. In addition, the study has detected that women had more commitment on their organization than men did. The proposed study of this paper has also considered a regression model where organizational commitment is dependent variable and trust and communication are considered as independent variables. According to the results of regression analysis, an increase of one unit in trust and social capital communication will increase organizational commitment by 0.189 and 0.204, respectively.
Stochastic programming with integer recourse
van der Vlerk, Maarten Hendrikus
1995-01-01
In this thesis we consider two-stage stochastic linear programming models with integer recourse. Such models are at the intersection of two different branches of mathematical programming. On the one hand some of the model parameters are random, which places the problem in the field of stochastic
Thermal mixtures in stochastic mechanics
Energy Technology Data Exchange (ETDEWEB)
Guerra, F [Rome Univ. (Italy). Ist. di Matematica; Loffredo, M I [Salerno Univ. (Italy). Ist. di Fisica
1981-01-17
Stochastic mechanics is extended to systems in thermal equilibrium. The resulting stochastic processes are mixtures of Nelson processes. Their Markov property is investigated in some simple cases. It is found that in order to inforce Markov property the algebra of observable associated to the present must be suitably enlarged.
Stochastic Pi-calculus Revisited
DEFF Research Database (Denmark)
Cardelli, Luca; Mardare, Radu Iulian
2013-01-01
We develop a version of stochastic Pi-calculus with a semantics based on measure theory. We dene the behaviour of a process in a rate environment using measures over the measurable space of processes induced by structural congruence. We extend the stochastic bisimulation to include the concept of...
Alternative Asymmetric Stochastic Volatility Models
M. Asai (Manabu); M.J. McAleer (Michael)
2010-01-01
textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is
Stochastic ferromagnetism analysis and numerics
Brzezniak, Zdzislaw; Neklyudov, Mikhail; Prohl, Andreas
2013-01-01
This monograph examines magnetization dynamics at elevated temperatures which can be described by the stochastic Landau-Lifshitz-Gilbert equation (SLLG). Comparative computational studies with the stochastic model are included. Constructive tools such as e.g. finite element methods are used to derive the theoretical results, which are then used for computational studies.
Variance decomposition in stochastic simulators.
Le Maître, O P; Knio, O M; Moraes, A
2015-06-28
This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.
Variance decomposition in stochastic simulators
Le Maître, O. P.; Knio, O. M.; Moraes, A.
2015-06-01
This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.
Brownian motion and stochastic calculus
Karatzas, Ioannis
1998-01-01
This book is designed as a text for graduate courses in stochastic processes. It is written for readers familiar with measure-theoretic probability and discrete-time processes who wish to explore stochastic processes in continuous time. The vehicle chosen for this exposition is Brownian motion, which is presented as the canonical example of both a martingale and a Markov process with continuous paths. In this context, the theory of stochastic integration and stochastic calculus is developed. The power of this calculus is illustrated by results concerning representations of martingales and change of measure on Wiener space, and these in turn permit a presentation of recent advances in financial economics (option pricing and consumption/investment optimization). This book contains a detailed discussion of weak and strong solutions of stochastic differential equations and a study of local time for semimartingales, with special emphasis on the theory of Brownian local time. The text is complemented by a large num...
Variance decomposition in stochastic simulators
Energy Technology Data Exchange (ETDEWEB)
Le Maître, O. P., E-mail: olm@limsi.fr [LIMSI-CNRS, UPR 3251, Orsay (France); Knio, O. M., E-mail: knio@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708 (United States); Moraes, A., E-mail: alvaro.moraesgutierrez@kaust.edu.sa [King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)
2015-06-28
This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.
Variance decomposition in stochastic simulators
Le Maî tre, O. P.; Knio, O. M.; Moraes, Alvaro
2015-01-01
This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.
Modeling stochastic frontier based on vine copulas
Constantino, Michel; Candido, Osvaldo; Tabak, Benjamin M.; da Costa, Reginaldo Brito
2017-11-01
This article models a production function and analyzes the technical efficiency of listed companies in the United States, Germany and England between 2005 and 2012 based on the vine copula approach. Traditional estimates of the stochastic frontier assume that data is multivariate normally distributed and there is no source of asymmetry. The proposed method based on vine copulas allow us to explore different types of asymmetry and multivariate distribution. Using data on product, capital and labor, we measure the relative efficiency of the vine production function and estimate the coefficient used in the stochastic frontier literature for comparison purposes. This production vine copula predicts the value added by firms with given capital and labor in a probabilistic way. It thereby stands in sharp contrast to the production function, where the output of firms is completely deterministic. The results show that, on average, S&P500 companies are more efficient than companies listed in England and Germany, which presented similar average efficiency coefficients. For comparative purposes, the traditional stochastic frontier was estimated and the results showed discrepancies between the coefficients obtained by the application of the two methods, traditional and frontier-vine, opening new paths of non-linear research.
Models of the stochastic activity of neurones
Holden, Arun Vivian
1976-01-01
These notes have grown from a series of seminars given at Leeds between 1972 and 1975. They represent an attempt to gather together the different kinds of model which have been proposed to account for the stochastic activity of neurones, and to provide an introduction to this area of mathematical biology. A striking feature of the electrical activity of the nervous system is that it appears stochastic: this is apparent at all levels of recording, ranging from intracellular recordings to the electroencephalogram. The chapters start with fluctuations in membrane potential, proceed through single unit and synaptic activity and end with the behaviour of large aggregates of neurones: L have chgaen this seque~~e\\/~~';uggest that the interesting behaviourr~f :the nervous system - its individuality, variability and dynamic forms - may in part result from the stochastic behaviour of its components. I would like to thank Dr. Julio Rubio for reading and commenting on the drafts, Mrs. Doris Beighton for producing the fin...
Brain-inspired Stochastic Models and Implementations
Al-Shedivat, Maruan
2015-05-12
One of the approaches to building artificial intelligence (AI) is to decipher the princi- ples of the brain function and to employ similar mechanisms for solving cognitive tasks, such as visual perception or natural language understanding, using machines. The recent breakthrough, named deep learning, demonstrated that large multi-layer networks of arti- ficial neural-like computing units attain remarkable performance on some of these tasks. Nevertheless, such artificial networks remain to be very loosely inspired by the brain, which rich structures and mechanisms may further suggest new algorithms or even new paradigms of computation. In this thesis, we explore brain-inspired probabilistic mechanisms, such as neural and synaptic stochasticity, in the context of generative models. The two questions we ask here are: (i) what kind of models can describe a neural learning system built of stochastic components? and (ii) how can we implement such systems e ̆ciently? To give specific answers, we consider two well known models and the corresponding neural architectures: the Naive Bayes model implemented with a winner-take-all spiking neural network and the Boltzmann machine implemented in a spiking or non-spiking fashion. We propose and analyze an e ̆cient neuromorphic implementation of the stochastic neu- ral firing mechanism and study the e ̄ects of synaptic unreliability on learning generative energy-based models implemented with neural networks.
Beijing: a conference of commitments?
Davis, S
1996-05-01
The author of this article holds the view that the Declaration and Platform for Action at the UN Fourth World Conference on Women held in Beijing in 1995 was the product of the most highly participatory process ever organized under the auspices of the UN. The Declaration and Platform expressed the strongest views on gender equality, empowerment, and justice that governments have ever endorsed. These documents were the consolidation of gains made by women in previous UN conferences. The 135-page Platform can be used at all levels of decision making. Governments and international can be held accountable for its provisions. The Platform exposes the problems violence and exploitation against women and girls as well as the revelation that environmental destruction is due to an unsustainable pattern of consumption and production, particularly in developed countries. Conference participants included about 3000 nongovernmental groups (NGOs). The Women's Linkage Caucus and WEDO served to facilitate the advocacy process by providing briefings on text still under negotiation and providing on-line recommendations from the 1995 and 1994 Commission on the Status of Women preparatory committee meetings. A scoreboard that tracked government's commitment at the 1995 preparatory committee meetings was reinstated in Beijing. The information was conveyed on the Internet. The European Union is credited with diluting the language about government commitment to the Platform. Governments are still given responsibility for implementation, and the need for political will is stressed (paragraph 293). Paragraph 297 indicates the process for implementation of the Platform and coordination with NGOs. Although the Platform recognizes the importance of women's groups and other NGOs, the responsibility for implementation is still given to governments.
Stochastic Optical Reconstruction Microscopy (STORM).
Xu, Jianquan; Ma, Hongqiang; Liu, Yang
2017-07-05
Super-resolution (SR) fluorescence microscopy, a class of optical microscopy techniques at a spatial resolution below the diffraction limit, has revolutionized the way we study biology, as recognized by the Nobel Prize in Chemistry in 2014. Stochastic optical reconstruction microscopy (STORM), a widely used SR technique, is based on the principle of single molecule localization. STORM routinely achieves a spatial resolution of 20 to 30 nm, a ten-fold improvement compared to conventional optical microscopy. Among all SR techniques, STORM offers a high spatial resolution with simple optical instrumentation and standard organic fluorescent dyes, but it is also prone to image artifacts and degraded image resolution due to improper sample preparation or imaging conditions. It requires careful optimization of all three aspects-sample preparation, image acquisition, and image reconstruction-to ensure a high-quality STORM image, which will be extensively discussed in this unit. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.
Factors Affecting Organizational Commitment in Navy Corpsmen.
Booth-Kewley, Stephanie; Dell'Acqua, Renée G; Thomsen, Cynthia J
2017-07-01
Organizational commitment is a psychological state that has a strong impact on the likelihood that employees will remain with an organization. Among military personnel, organizational commitment is predictive of a number of important outcomes, including reenlistment intentions, job performance, morale, and perceived readiness. Because of the unique challenges and experiences associated with military service, it may be that organizational commitment is even more critical in the military than in civilian populations. Despite the essential role that they play in protecting the health of other service members, little is known about the factors that influence Navy Corpsmen's organizational commitment. This study investigated demographic and psychosocial factors that may be associated with organizational commitment among Corpsmen. Surveys of organizational commitment and possible demographic and psychosocial correlates of organizational commitment were completed by 1,597 male, active duty Navy Corpsmen attending Field Medical Training Battalion-West, Camp Pendleton, California. Bivariate correlations and hierarchical multiple regression analyses were used to determine significant predictors of organizational commitment. Of the 12 demographic and psychosocial factors examined, 6 factors emerged as significant predictors of organizational commitment in the final model: preservice motivation to be a Corpsman, positive perceptions of Corpsman training, confidence regarding promotions, occupational self-efficacy, social support for a Corpsman career, and lower depression. Importantly, a number of the factors that emerged as significant correlates of organizational commitment in this study are potentially modifiable. These factors include confidence regarding promotions, positive perceptions of Corpsman training, and occupational self-efficacy. It is recommended that military leaders and policy-makers take concrete steps to address these factors, thereby strengthening
Disaggregated Futures and Options Commitments of Traders
Commodity Futures Trading Commission — The Disaggregated Futures and Options Commitments of Traders dataset provides a breakdown of each week's open interest for agriculture, energy, metals, lumber, and...
Family Commitment and Work Characteristics among Pharmacists.
Gubbins, Paul O; Ragland, Denise; Castleberry, Ashley N; Payakachat, Nalin
2015-12-17
Factors associated with family commitment among pharmacists in the south central U.S. are explored. In 2010, a cross-sectional mailed self-administered 70 item survey of 363 active licensed pharmacists was conducted. This analysis includes only 269 (74%) participants who reported being married. Outcome measures were family commitment (need for family commitment, spouse's family commitment), work-related characteristics (work challenge, stress, workload, flexibility of work schedule), and job and career satisfaction. Married participants' mean age was 48 (SD = 18) years; the male to female ratio was 1:1; 73% worked in retail settings and 199 (74%) completed the family commitment questions. Females reported a higher need for family commitment than males ( p = 0.02) but there was no significant difference in satisfaction with the commitment. Work challenge and work load were significantly associated with higher need for family commitment ( p work status, and practice setting. Higher work challenge was associated with higher career satisfaction. Higher job related stress was associated with lower job satisfaction. High work challenge and work load may negatively impact family function since married pharmacists would need higher family commitment from their counterparts. The impact of work-family interactions on pharmacy career satisfaction should be further investigated.
Work engagement, organizational commitment, self efficacy and ...
African Journals Online (AJOL)
Information Impact: Journal of Information and Knowledge Management ... Work engagement, organizational commitment and self-efficacy will create a positive ... effective training, counseling, effective communication and leadership skills.
Family Commitment and Work Characteristics among Pharmacists
Directory of Open Access Journals (Sweden)
Paul O. Gubbins
2015-12-01
Full Text Available Factors associated with family commitment among pharmacists in the south central U.S. are explored. In 2010, a cross-sectional mailed self-administered 70 item survey of 363 active licensed pharmacists was conducted. This analysis includes only 269 (74% participants who reported being married. Outcome measures were family commitment (need for family commitment, spouse’s family commitment, work-related characteristics (work challenge, stress, workload, flexibility of work schedule, and job and career satisfaction. Married participants’ mean age was 48 (SD = 18 years; the male to female ratio was 1:1; 73% worked in retail settings and 199 (74% completed the family commitment questions. Females reported a higher need for family commitment than males (p = 0.02 but there was no significant difference in satisfaction with the commitment. Work challenge and work load were significantly associated with higher need for family commitment (p < 0.01, when controlled for age, gender, number of dependents, work status, and practice setting. Higher work challenge was associated with higher career satisfaction. Higher job related stress was associated with lower job satisfaction. High work challenge and work load may negatively impact family function since married pharmacists would need higher family commitment from their counterparts. The impact of work-family interactions on pharmacy career satisfaction should be further investigated.
Disaggregated Futures-Only Commitments of Traders
Commodity Futures Trading Commission — The Disaggregated Futures-Only Commitments of Traders dataset provides a breakdown of each week's open interest for agriculture, energy, metals, lumber, and...
A storage-based model of heterocyst commitment and patterning in cyanobacteria
International Nuclear Information System (INIS)
Brown, Aidan I; Rutenberg, Andrew D
2014-01-01
When deprived of fixed nitrogen (fN), certain filamentous cyanobacteria differentiate nitrogen-fixing heterocysts. There is a large and dynamic fraction of stored fN in cyanobacterial cells, but its role in directing heterocyst commitment has not been identified. We present an integrated computational model of fN transport, cellular growth, and heterocyst commitment for filamentous cyanobacteria. By including fN storage proportional to cell length, but without any explicit cell-cycle effect, we are able to recover a broad and late range of heterocyst commitment times and we observe a strong indirect cell-cycle effect. We propose that fN storage is an important component of heterocyst commitment and patterning in filamentous cyanobacteria. The model allows us to explore both initial and steady-state heterocyst patterns. The developmental model is hierarchical after initial commitment: our only source of stochasticity is observed growth rate variability. Explicit lateral inhibition allows us to examine ΔpatS, ΔhetN, and ΔpatN phenotypes. We find that ΔpatS leads to adjacent heterocysts of the same generation, while ΔhetN leads to adjacent heterocysts only of different generations. With a shortened inhibition range, heterocyst spacing distributions are similar to those in experimental ΔpatN systems. Step-down to non-zero external fN concentrations is also investigated. (paper)
Committed, engaged e applied anthropology - Committed, engaged and applied anthropology
Directory of Open Access Journals (Sweden)
Antonio Luigi Palmisano
2014-11-01
Full Text Available Anthropology has become very popular over the past decades. We have witnessed a proliferation of anthropologists and anthropologies but the theoretical debate and the epistemological reflection of the discipline have come to a full stop. It seems that anthropology has reduced itself to a tekhne among many others, characterizing itself – according to the author – as «Atlantic anthropology», a protocolar anthropology in thrall to the dominating ideologies of the financial markets. The renewed discussion on the concepts of development and cooperation – concepts which have deeply marked the past three decades of social sciences and the current crystallization of anthropology – that is of contemporary economy, represents an opportunity to revivify and deepen the impact of anthropological theory. It is an epistemological and political impact with remarkable social and scientific consequences which is mostly detectable in one of the declinations of anthropology, i.e. applied anthropology, when and if intended as committed anthropology that founds its methodology and its way of being on fieldwork: a continuous dialogue with “alterity” in which the only thinkable “alienity” is represented by the tekhne and by the financial markets which support and promulgate it as omnipresent and almighty verbum.
Morgan, Byron JT; Tanner, Martin Abba; Carlin, Bradley P
2008-01-01
Introduction and Examples Introduction Examples of data sets Basic Model Fitting Introduction Maximum-likelihood estimation for a geometric model Maximum-likelihood for the beta-geometric model Modelling polyspermy Which model? What is a model for? Mechanistic models Function Optimisation Introduction MATLAB: graphs and finite differences Deterministic search methods Stochastic search methods Accuracy and a hybrid approach Basic Likelihood ToolsIntroduction Estimating standard errors and correlations Looking at surfaces: profile log-likelihoods Confidence regions from profiles Hypothesis testing in model selectionScore and Wald tests Classical goodness of fit Model selection biasGeneral Principles Introduction Parameterisation Parameter redundancy Boundary estimates Regression and influence The EM algorithm Alternative methods of model fitting Non-regular problemsSimulation Techniques Introduction Simulating random variables Integral estimation Verification Monte Carlo inference Estimating sampling distributi...
Stochastic population theories
Ludwig, Donald
1974-01-01
These notes serve as an introduction to stochastic theories which are useful in population biology; they are based on a course given at the Courant Institute, New York, in the Spring of 1974. In order to make the material. accessible to a wide audience, it is assumed that the reader has only a slight acquaintance with probability theory and differential equations. The more sophisticated topics, such as the qualitative behavior of nonlinear models, are approached through a succession of simpler problems. Emphasis is placed upon intuitive interpretations, rather than upon formal proofs. In most cases, the reader is referred elsewhere for a rigorous development. On the other hand, an attempt has been made to treat simple, useful models in some detail. Thus these notes complement the existing mathematical literature, and there appears to be little duplication of existing works. The authors are indebted to Miss Jeanette Figueroa for her beautiful and speedy typing of this work. The research was supported by the Na...
Propagator of stochastic electrodynamics
International Nuclear Information System (INIS)
Cavalleri, G.
1981-01-01
The ''elementary propagator'' for the position of a free charged particle subject to the zero-point electromagnetic field with Lorentz-invariant spectral density proportionalω 3 is obtained. The nonstationary process for the position is solved by the stationary process for the acceleration. The dispersion of the position elementary propagator is compared with that of quantum electrodynamics. Finally, the evolution of the probability density is obtained starting from an initial distribution confined in a small volume and with a Gaussian distribution in the velocities. The resulting probability density for the position turns out to be equal, to within radiative corrections, to psipsi* where psi is the Kennard wave packet. If the radiative corrections are retained, the present result is new since the corresponding expression in quantum electrodynamics has not yet been found. Besides preceding quantum electrodynamics for this problem, no renormalization is required in stochastic electrodynamics
Efficiency in the Community College Sector: Stochastic Frontier Analysis
Agasisti, Tommaso; Belfield, Clive
2017-01-01
This paper estimates technical efficiency scores across the community college sector in the United States. Using stochastic frontier analysis and data from the Integrated Postsecondary Education Data System for 2003-2010, we estimate efficiency scores for 950 community colleges and perform a series of sensitivity tests to check for robustness. We…
Stochastic Predictive Control of Multi-Microgrid Systems
DEFF Research Database (Denmark)
Bazmohammadi, Najmeh; Tahsiri, Ahmadreza; Anvari-Moghaddam, Amjad
2018-01-01
This paper presents a stochastic predictive control algorithm for a number of microgrids connected to the same distribution system. Each microgrid includes a variety of distributed resources such as wind turbine, photo voltaic units, energy storage devices and loads. Considering the uncertainty...
Vandenberghe, Christian; Bentein, Kathleen; Michon, Richard; Chebat, Jean-Charles; Tremblay, Michel; Fils, Jean-François
2007-07-01
The authors examined the relationships between perceived organizational support, organizational commitment, commitment to customers, and service quality in a fast-food firm. The research design matched customer responses with individual employees' attitudes, making this study a true test of the service provider-customer encounter. On the basis of a sample of matched employee-customer data (N = 133), hierarchical linear modeling analyses revealed that perceived organizational support had both a unit-level and an employee-level effect on 1 dimension of service quality: helping behavior. Contrary to affective organizational commitment, affective commitment to customers enhanced service quality. The 2 sub-dimensions of continuance commitment to the organization--perceived high sacrifice and perceived lack of alternatives--exerted effects opposite in sign: The former fostered service quality, whereas the latter reduced it. The implications of these findings are discussed within the context of research on employee-customer encounters.
STOCHSIMGPU: parallel stochastic simulation for the Systems Biology Toolbox 2 for MATLAB
Klingbeil, G.
2011-02-25
Motivation: The importance of stochasticity in biological systems is becoming increasingly recognized and the computational cost of biologically realistic stochastic simulations urgently requires development of efficient software. We present a new software tool STOCHSIMGPU that exploits graphics processing units (GPUs) for parallel stochastic simulations of biological/chemical reaction systems and show that significant gains in efficiency can be made. It is integrated into MATLAB and works with the Systems Biology Toolbox 2 (SBTOOLBOX2) for MATLAB. Results: The GPU-based parallel implementation of the Gillespie stochastic simulation algorithm (SSA), the logarithmic direct method (LDM) and the next reaction method (NRM) is approximately 85 times faster than the sequential implementation of the NRM on a central processing unit (CPU). Using our software does not require any changes to the user\\'s models, since it acts as a direct replacement of the stochastic simulation software of the SBTOOLBOX2. © The Author 2011. Published by Oxford University Press. All rights reserved.
RES: Regularized Stochastic BFGS Algorithm
Mokhtari, Aryan; Ribeiro, Alejandro
2014-12-01
RES, a regularized stochastic version of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton method is proposed to solve convex optimization problems with stochastic objectives. The use of stochastic gradient descent algorithms is widespread, but the number of iterations required to approximate optimal arguments can be prohibitive in high dimensional problems. Application of second order methods, on the other hand, is impracticable because computation of objective function Hessian inverses incurs excessive computational cost. BFGS modifies gradient descent by introducing a Hessian approximation matrix computed from finite gradient differences. RES utilizes stochastic gradients in lieu of deterministic gradients for both, the determination of descent directions and the approximation of the objective function's curvature. Since stochastic gradients can be computed at manageable computational cost RES is realizable and retains the convergence rate advantages of its deterministic counterparts. Convergence results show that lower and upper bounds on the Hessian egeinvalues of the sample functions are sufficient to guarantee convergence to optimal arguments. Numerical experiments showcase reductions in convergence time relative to stochastic gradient descent algorithms and non-regularized stochastic versions of BFGS. An application of RES to the implementation of support vector machines is developed.
Committing to coal and gas: Long-term contracts, regulation, and fuel switching in power generation
Rice, Michael
Fuel switching in the electricity sector has important economic and environmental consequences. In the United States, the increased supply of gas during the last decade has led to substantial switching in the short term. Fuel switching is constrained, however, by the existing infrastructure. The power generation infrastructure, in turn, represents commitments to specific sources of energy over the long term. This dissertation explores fuel contracts as the link between short-term price response and long-term plant investments. Contracting choices enable power plant investments that are relationship-specific, often regulated, and face uncertainty. Many power plants are subject to both hold-up in investment and cost-of-service regulation. I find that capital bias is robust when considering either irreversibility or hold-up due to the uncertain arrival of an outside option. For sunk capital, the rental rate is inappropriate for determining capital bias. Instead, capital bias depends on the regulated rate of return, discount rate, and depreciation schedule. If policies such as emissions regulations increase fuel-switching flexibility, this can lead to capital bias. Cost-of-service regulation can shorten the duration of a long-term contract. From the firm's perspective, the existing literature provides limited guidance when bargaining and writing contracts for fuel procurement. I develop a stochastic programming framework to optimize long-term contracting decisions under both endogenous and exogenous sources of hold-up risk. These typically include policy changes, price shocks, availability of fuel, and volatility in derived demand. For price risks, the optimal contract duration is the moment when the expected benefits of the contract are just outweighed by the expected opportunity costs of remaining in the contract. I prove that imposing early renegotiation costs decreases contract duration. Finally, I provide an empirical approach to show how coal contracts can limit
Directory of Open Access Journals (Sweden)
Suhaiza Ismail
2015-08-01
Full Text Available The objective of this paper is to investigate the effect of the ethical climate on the organizational commitment, professional commitment and job satisfaction of Malaysian auditors. Using a survey questionnaire comprising instruments about the ethical climate, organizational commitment, professional commitment and job satisfaction, 263 usable responses were received. To achieve the objectives, mean scores, standard deviations, correlations and multiple regressions were performed. The study revealed that a significant positive influence of a caring ethical climate on professional and organizational commitment as well as job satisfaction existed. There was also a positive significant association between the law and code ethical climate and professional commitment. On the other hand, the study discovered that the instrumental ethical climate type had a significant negative relationship with organizational commitment and job satisfaction. A significant negative relationship was also revealed between the independent ethical climate type and organizational and professional commitment. A significant negative relationship between the rules ethical climate and job satisfaction was also discovered.
Stochastic estimation of electricity consumption
International Nuclear Information System (INIS)
Kapetanovic, I.; Konjic, T.; Zahirovic, Z.
1999-01-01
Electricity consumption forecasting represents a part of the stable functioning of the power system. It is very important because of rationality and increase of control process efficiency and development planning of all aspects of society. On a scientific basis, forecasting is a possible way to solve problems. Among different models that have been used in the area of forecasting, the stochastic aspect of forecasting as a part of quantitative models takes a very important place in applications. ARIMA models and Kalman filter as stochastic estimators have been treated together for electricity consumption forecasting. Therefore, the main aim of this paper is to present the stochastic forecasting aspect using short time series. (author)
Linear stochastic neutron transport theory
International Nuclear Information System (INIS)
Lewins, J.
1978-01-01
A new and direct derivation of the Bell-Pal fundamental equation for (low power) neutron stochastic behaviour in the Boltzmann continuum model is given. The development includes correlation of particle emission direction in induced and spontaneous fission. This leads to generalizations of the backward and forward equations for the mean and variance of neutron behaviour. The stochastic importance for neutron transport theory is introduced and related to the conventional deterministic importance. Defining equations and moment equations are derived and shown to be related to the backward fundamental equation with the detector distribution of the operational definition of stochastic importance playing the role of an adjoint source. (author)
Stochasticity in the Josephson map
International Nuclear Information System (INIS)
Nomura, Y.; Ichikawa, Y.H.; Filippov, A.T.
1996-04-01
The Josephson map describes nonlinear dynamics of systems characterized by standard map with the uniform external bias superposed. The intricate structures of the phase space portrait of the Josephson map are examined on the basis of the tangent map associated with the Josephson map. Numerical observation of the stochastic diffusion in the Josephson map is examined in comparison with the renormalized diffusion coefficient calculated by the method of characteristic function. The global stochasticity of the Josephson map occurs at the values of far smaller stochastic parameter than the case of the standard map. (author)
Introduction to stochastic dynamic programming
Ross, Sheldon M; Lukacs, E
1983-01-01
Introduction to Stochastic Dynamic Programming presents the basic theory and examines the scope of applications of stochastic dynamic programming. The book begins with a chapter on various finite-stage models, illustrating the wide range of applications of stochastic dynamic programming. Subsequent chapters study infinite-stage models: discounting future returns, minimizing nonnegative costs, maximizing nonnegative returns, and maximizing the long-run average return. Each of these chapters first considers whether an optimal policy need exist-providing counterexamples where appropriate-and the
Ismail, Suhaiza
2015-01-01
The objective of this paper is to investigate the effect of the ethical climate on the organizational commitment, professional commitment and job satisfaction of Malaysian auditors. Using a survey questionnaire comprising instruments about the ethical climate, organizational commitment, professional commitment and job satisfaction, 263 usable responses were received. To achieve the objectives, mean scores, standard deviations, correlations and multiple regressions were performed. The study re...
Functional Abstraction of Stochastic Hybrid Systems
Bujorianu, L.M.; Blom, Henk A.P.; Hermanns, H.
2006-01-01
The verification problem for stochastic hybrid systems is quite difficult. One method to verify these systems is stochastic reachability analysis. Concepts of abstractions for stochastic hybrid systems are needed to ease the stochastic reachability analysis. In this paper, we set up different ways
An introduction to probability and stochastic processes
Melsa, James L
2013-01-01
Geared toward college seniors and first-year graduate students, this text is designed for a one-semester course in probability and stochastic processes. Topics covered in detail include probability theory, random variables and their functions, stochastic processes, linear system response to stochastic processes, Gaussian and Markov processes, and stochastic differential equations. 1973 edition.
[Influence of organizational commitment and professional nurses in conflict resolution strategies].
Pinho, Paula; Albuquerque, Carlos
2013-01-01
INTRODUCE: The changes in the health area and the set of structural changes in the nursing profession and career interfere in the dynamics and stability of the future of the nurses. To study the influence of organizational and professional commitment of the nurses in the strategies of conflict resolution. This is a quantitative, transversal and non-experimental research, following a descriptive-correlational way. Non-probabilistic sample of 102 nurses to perform duties in Health Units, mostly female (82.4%) with a mean age of 39.33 years and standard deviation 9.226. The measuring instrument consists of three scales calibrated and validated for the portuguese population: Organizational Commitment Questionnaire, Professional Commitment Scale and Inventory Strategies for Conflict Resolution, which assesses how individuals deal with conflict situations before higher (Form A), subordinate (Form B) and colleagues (Form C). Nurses demonstrate a moderate organizational commitment and higher affective commitment and normative commitment to the instrumental. Nurses demonstrate a moderate professional commitment and the results show that nurses have higher values on the dimensions of that interest and challenge the relevance dimension of nursing as a profession. The organizational commitment influences the adoption of strategies of conflict resolution as a conflict situation arises with the boss, subordinates or colleagues. The higher the level of organizational commitment higher the level of professional commitment. Nurses more engaged professionally demonstrate strategies that use more integrative and compromise in conflict resolution whether against the boss, subordinates or colleagues. The results ensure the need to promote and stimulate the affective commitment by the positive consequences it entails the organization and the profession. The organizational performance benefits from the stimulation of the conflict under certain conditions and that the constructive
Decision to commit crime: rational or nonrational
Directory of Open Access Journals (Sweden)
Glenn D. Walters
2016-09-01
Full Text Available Objective to prove the necessity to take into account the influence of emotions on decision making to describe a combined model of the decision making process which unites rational and irrational components of choice in crime commitment. Methods dialectic systemic historicallegal formaljuridical methods summarization. Results the paper gives a complex analysis of the criminal decisionmaking process and reveals the factors increasing the probability of antisocial actions. The value of the combined cognitiveemotive model is that emotions can give more significant information to the decisionmaker than reasoning. Scientific novelty the author proposes a theory of decision making which says that a person chooses to act or not to act under hedonistic or moral emotions while the irrelevant emotions are increased and the relevant ones are suppressed by cognitive and situational factors serving as a basis for criminal decision making. Practical significance studying the role of emotions in the criminal and noncriminal decision making will significantly contribute to the development of criminology. The research results will be useful for researchers and lawenforcement bodies as well as for all those who are interested in the issues of crime control and prevention.
Host-country policy – commitment or no-commitment: a theoretical analysis
Mukherjee, A.
2000-01-01
This paper develops a model of foreign entry strategy and examines welfare of the host-country under two situations - (i) where host-country government commits to the tax policy, (ii) where host-country government does not commit to the tax policy. It turns out that under the non-committed
Employee commitment and performance of manufacturing firms ...
African Journals Online (AJOL)
445) between job satisfaction and employee organizational commitment. Multiple regression revealed that pay and job promotion are the important elements that influence employee commitment. It is recommended that manufacturing organizations should emphasize pay and job promotion to enhance higher employee ...
Making Commitments to Racial Justice Actionable
Diab, Rasha; Ferrel, Thomas; Godbee, Beth; Simpkins, Neil
2013-01-01
In this article, we articulate a framework for making our commitments to racial justice actionable, a framework that moves from narrating confessional accounts to articulating our commitments and then acting on them through both self-work and work-with-others, a dialectic possibility we identify and explore. We model a method for moving beyond…
Sexually Violent Predators and Civil Commitment Laws
Beyer Kendall, Wanda D.; Cheung, Monit
2004-01-01
This article analyzes the civil commitment models for treating sexually violent predators (SVPs) and analyzes recent civil commitment laws. SVPs are commonly defined as sex offenders who are particularly predatory and repetitive in their sexually violent behavior. Data from policy literature, a survey to all states, and a review of law review…
Understanding the Links between Work Commitment Constructs.
Hackett, Rick D.; Lapierre, Laurent M.; Hausdorf, Peter A.
2001-01-01
In a study of 852 nurses, work involvement (value of work in their lives) affected organizational and occupational commitment through its effect on job involvement. Job involvement indirectly affected intention to leave the organization or occupation. Work and job involvement and orgnanizational and occupational commitment were determined to be…
7 CFR 3550.70 - Conditional commitments.
2010-01-01
..., dealer-contractor, or seller must: (1) Have an adequate ownership interest in the property, as defined in... approval of an affirmative marketing plan. (b) Limitations. Conditional commitments for new or... as bad weather, materials shortages, or marketing difficulties. Conditional commitments may be...
The Influence of Culture on Teacher Commitment
Abd Razak, Nordin; Darmawan, I. Gusti Ngurah; Keeves, John P.
2010-01-01
Culture is believed to be an important factor that influences various aspects of human life, such as behaviour, thinking, perceptions and attitudes. This article examines the similarities and differences in the influence of culture on teacher commitment in three types of Malaysian primary schools. Since commitment to teaching has rarely been…
On Entry Deterrence and Imperfectly Observable Commitment
DEFF Research Database (Denmark)
Poulsen, Anders
2001-01-01
We analyse a simple entry-deterrence game, where a `Potential Intruder' only imperfectly observes the decision of an `Incumbent' to commit or to not commit to fight any entry by the Potential Intruder. Our game generalises the one studied in Bonanno (1992) by allowing for a richer information tec...
Juvenile Court Commitment Rates: The National Picture.
Sosin, Michael
There is less geographic variation in the commitment rate of juvenile offenders than is commonly assumed. Apparently, judges across the country develop a similar standard of what percentage of youths they face should be committed. This standard may be similar across the country because it represents broadly shared ideals. However, there is much…
Education on the Internet: Anonymity vs. Commitment.
Dreyfus, Hubert L.
1998-01-01
Argues that learning a skill requires the kind of commitment which is undermined by the Press (the Public) and the Internet, citing Soren Kierkegaard's "The Present Age", and states that learning by apprenticeship is impossible in cyberspace. Includes: aesthetic sphere--commitment to the enjoyment of sheer information; ethical…
The Behavioral Expression of Organizational Commitment.
Randall, Donna M.; And Others
1990-01-01
Explored within empirical study context complexity of organizational commitment construct and respondent-generated behavioral manifestations of job attitude among plant workers (N=156). Found each commitment dimension related differently to work outcomes and that none of the dimensions was able to predict absenteeism or tardiness. (Author/CM)
Dual or dueling culture and commitment: The impact of a tri-hospital merger.
Jones, Janice M
2003-04-01
This article addresses differences in RNs' commitment to their employing hospital versus the umbrella corporate organization, and the role of organizational culture during a tri-hospital merger. This study is the first to investigate the construct of dual commitment in healthcare organizations. Fiscal restraints, decreasing reimbursement, and increasing competition have made organizational mergers and acquisitions prevalent. As corporate culture changes, organizational variables previously related to organizational commitment may no longer apply. RNs employed on general nursing units at 3 hospitals involved in a merger process completed 2 versions of Mowday's Organizational Commitment Questionnaire. Commitment to hospital and corporate system were examined. Semi-structured interviews, participant observation, and analysis of company documents assessed the organizational culture changes that have occurred. Thirty-one percent of the nurses returned completed questionnaires; 9 were interviewed. RNs from the acquiring hospital demonstrated a significantly stronger commitment to the corporate system than the nurses from the acquired hospitals. The RNs at all 3 hospitals showed significantly greater commitment to their own particular hospital than to the umbrella corporate system. Moderate level of commitment reflected uncertainty of job status, work overload, and feelings of unappreciation. These attitudes prevent nurses from exerting efforts on behalf of the organization.
Organizational culture and organizational commitment: Serbian case
Directory of Open Access Journals (Sweden)
Mitić Siniša
2016-01-01
Full Text Available The paper presents the results of the impact of certain dimensions of organizational culture (Future Orientation, Power Distance, Human Orientation and Performance Orientation on organizational commitment in companies in Serbia. Through a survey, responses were obtained from a total of N = 400 middle managers from 129 companies. The results show a statistically significant correlation between the observed dimensions of organizational culture and organizational commitment dimensions. Also, there is a statistically significant predictive effect of certain dimensions of organizational culture on the dimensions of organizational commitment. The biggest influences on the dimensions of organizational commitment have dimensions Future Orientation - FO and Performance Orientation - PO. On the other hand, under the most affected dimension of organizational culture is the dimension of organizational commitment Organizational identification - OCM1.
Stochastic backgrounds of gravitational waves
International Nuclear Information System (INIS)
Maggiore, M.
2001-01-01
We review the motivations for the search for stochastic backgrounds of gravitational waves and we compare the experimental sensitivities that can be reached in the near future with the existing bounds and with the theoretical predictions. (author)
Stochastic theories of quantum mechanics
International Nuclear Information System (INIS)
De la Pena, L.; Cetto, A.M.
1991-01-01
The material of this article is organized into five sections. In Sect. I the basic characteristics of quantum systems are briefly discussed, with emphasis on their stochastic properties. In Sect. II a version of stochastic quantum mechanics is presented, to conclude that the quantum formalism admits an interpretation in terms of stochastic processes. In Sect. III the elements of stochastic electrodynamics are described, and its possibilities and limitations as a fundamental theory of quantum systems are discussed. Section IV contains a recent reformulation that overcomes the limitations of the theory discussed in the foregoing section. Finally, in Sect. V the theorems of EPR, Von Neumann and Bell are discussed briefly. The material is pedagogically presented and includes an ample list of references, but the details of the derivations are generally omitted. (Author)
International Nuclear Information System (INIS)
Faris, W.G.
1981-01-01
Dankel has shown how to incorporate spin into stochastic mechanics. The resulting non-local hidden variable theory gives an appealing picture of spin correlation experiments in which Bell's inequality is violated. (orig.)
Statistical inference for stochastic processes
National Research Council Canada - National Science Library
Basawa, Ishwar V; Prakasa Rao, B. L. S
1980-01-01
The aim of this monograph is to attempt to reduce the gap between theory and applications in the area of stochastic modelling, by directing the interest of future researchers to the inference aspects...
Stochastic singular optics (Conference paper)
CSIR Research Space (South Africa)
Roux, FS
2014-09-01
Full Text Available The study of optical vortices in stochastic optical fields involves various quantities, including the vortex density and topological charge density, that are defined in terms of local expectation values of distributions of optical vortices...
The Factors of Strategic Leadership on Commitment: An Empirical Banking in Indonesia
Directory of Open Access Journals (Sweden)
Juliansyah Noor
2013-12-01
Full Text Available This research is aimed at obtaining information related to possibility whether organizational commitment is affected by training, organization culture, and ethical practice. The data which had been analyzed by multi regression analysis after all variables had been put into principal factor analysis. In this research employees were chosen as a unit analysis and 120 samples selected randomly.The result of this study shows that organization commitment is positively affected by training, organization culture and ethical practice. Implications of organization commitment might have been effected by training, organization culture and ethical practice as a strategic leadership.
Stochastic massless fields I: Integer spin
International Nuclear Information System (INIS)
Lim, S.C.
1981-04-01
Nelson's stochastic quantization scheme is applied to classical massless tensor potential in ''Coulomb'' gauge. The relationship between stochastic potential field in various gauges is discussed using the case of vector potential as an illustration. It is possible to identify the Euclidean tensor potential with the corresponding stochastic field in physical Minkowski space-time. Stochastic quantization of massless fields can also be carried out in terms of field strength tensors. An example of linearized stochastic gravitational field in vacuum is given. (author)
Stochastic theory of fatigue corrosion
Hu, Haiyun
1999-10-01
A stochastic theory of corrosion has been constructed. The stochastic equations are described giving the transportation corrosion rate and fluctuation corrosion coefficient. In addition the pit diameter distribution function, the average pit diameter and the most probable pit diameter including other related empirical formula have been derived. In order to clarify the effect of stress range on the initiation and growth behaviour of pitting corrosion, round smooth specimen were tested under cyclic loading in 3.5% NaCl solution.
Stochastic quantization and gauge theories
International Nuclear Information System (INIS)
Kolck, U. van.
1987-01-01
Stochastic quantization is presented taking the Flutuation-Dissipation Theorem as a guide. It is shown that the original approach of Parisi and Wu to gauge theories fails to give the right results to gauge invariant quantities when dimensional regularization is used. Although there is a simple solution in an abelian theory, in the non-abelian case it is probably necessary to start from a BRST invariant action instead of a gauge invariant one. Stochastic regularizations are also discussed. (author) [pt
Stochasticity induced by coherent wavepackets
International Nuclear Information System (INIS)
Fuchs, V.; Krapchev, V.; Ram, A.; Bers, A.
1983-02-01
We consider the momentum transfer and diffusion of electrons periodically interacting with a coherent longitudinal wavepacket. Such a problem arises, for example, in lower-hybrid current drive. We establish the stochastic threshold, the stochastic region δv/sub stoch/ in velocity space, the associated momentum transfer j, and the diffusion coefficient D. We concentrate principally on the weak-field regime, tau/sub autocorrelation/ < tau/sub bounce/
Stochastic runaway of dynamical systems
International Nuclear Information System (INIS)
Pfirsch, D.; Graeff, P.
1984-10-01
One-dimensional, stochastic, dynamical systems are well studied with respect to their stability properties. Less is known for the higher dimensional case. This paper derives sufficient and necessary criteria for the asymptotic divergence of the entropy (runaway) and sufficient ones for the moments of n-dimensional, stochastic, dynamical systems. The crucial implication is the incompressibility of their flow defined by the equations of motion in configuration space. Two possible extensions to compressible flow systems are outlined. (orig.)
Stochastic Models of Polymer Systems
2016-01-01
Distribution Unlimited Final Report: Stochastic Models of Polymer Systems The views, opinions and/or findings contained in this report are those of the...ADDRESS. Princeton University PO Box 0036 87 Prospect Avenue - 2nd floor Princeton, NJ 08544 -2020 14-Mar-2014 ABSTRACT Number of Papers published in...peer-reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: Stochastic Models of Polymer Systems Report Title
Stochastic efficiency: five case studies
International Nuclear Information System (INIS)
Proesmans, Karel; Broeck, Christian Van den
2015-01-01
Stochastic efficiency is evaluated in five case studies: driven Brownian motion, effusion with a thermo-chemical and thermo-velocity gradient, a quantum dot and a model for information to work conversion. The salient features of stochastic efficiency, including the maximum of the large deviation function at the reversible efficiency, are reproduced. The approach to and extrapolation into the asymptotic time regime are documented. (paper)
Optimal Liquidation under Stochastic Liquidity
Becherer, Dirk; Bilarev, Todor; Frentrup, Peter
2016-01-01
We solve explicitly a two-dimensional singular control problem of finite fuel type for infinite time horizon. The problem stems from the optimal liquidation of an asset position in a financial market with multiplicative and transient price impact. Liquidity is stochastic in that the volume effect process, which determines the inter-temporal resilience of the market in spirit of Predoiu, Shaikhet and Shreve (2011), is taken to be stochastic, being driven by own random noise. The optimal contro...
Memory effects on stochastic resonance
Neiman, Alexander; Sung, Wokyung
1996-02-01
We study the phenomenon of stochastic resonance (SR) in a bistable system with internal colored noise. In this situation the system possesses time-dependent memory friction connected with noise via the fluctuation-dissipation theorem, so that in the absence of periodic driving the system approaches the thermodynamic equilibrium state. For this non-Markovian case we find that memory usually suppresses stochastic resonance. However, for a large memory time SR can be enhanced by the memory.
Stochastic optimization: beyond mathematical programming
CERN. Geneva
2015-01-01
Stochastic optimization, among which bio-inspired algorithms, is gaining momentum in areas where more classical optimization algorithms fail to deliver satisfactory results, or simply cannot be directly applied. This presentation will introduce baseline stochastic optimization algorithms, and illustrate their efficiency in different domains, from continuous non-convex problems to combinatorial optimization problem, to problems for which a non-parametric formulation can help exploring unforeseen possible solution spaces.
Stochastic quantization and gauge invariance
International Nuclear Information System (INIS)
Viana, R.L.
1987-01-01
A survey of the fundamental ideas about Parisi-Wu's Stochastic Quantization Method, with applications to Scalar, Gauge and Fermionic theories, is done. In particular, the Analytic Stochastic Regularization Scheme is used to calculate the polarization tensor for Quantum Electrodynamics with Dirac bosons or Fermions. The regularization influence is studied for both theories and an extension of this method for some supersymmetrical models is suggested. (author)
Stochastic Analysis and Related Topics
Ustunel, Ali
1988-01-01
The Silvri Workshop was divided into a short summer school and a working conference, producing lectures and research papers on recent developments in stochastic analysis on Wiener space. The topics treated in the lectures relate to the Malliavin calculus, the Skorohod integral and nonlinear functionals of white noise. Most of the research papers are applications of these subjects. This volume addresses researchers and graduate students in stochastic processes and theoretical physics.
Phenomenology of stochastic exponential growth
Pirjol, Dan; Jafarpour, Farshid; Iyer-Biswas, Srividya
2017-06-01
Stochastic exponential growth is observed in a variety of contexts, including molecular autocatalysis, nuclear fission, population growth, inflation of the universe, viral social media posts, and financial markets. Yet literature on modeling the phenomenology of these stochastic dynamics has predominantly focused on one model, geometric Brownian motion (GBM), which can be described as the solution of a Langevin equation with linear drift and linear multiplicative noise. Using recent experimental results on stochastic exponential growth of individual bacterial cell sizes, we motivate the need for a more general class of phenomenological models of stochastic exponential growth, which are consistent with the observation that the mean-rescaled distributions are approximately stationary at long times. We show that this behavior is not consistent with GBM, instead it is consistent with power-law multiplicative noise with positive fractional powers. Therefore, we consider this general class of phenomenological models for stochastic exponential growth, provide analytical solutions, and identify the important dimensionless combination of model parameters, which determines the shape of the mean-rescaled distribution. We also provide a prescription for robustly inferring model parameters from experimentally observed stochastic growth trajectories.
Groenenberg, Heleen
2002-01-01
A key issue in climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC) is how future commitments can be differentiated amongst countries. This thesis focuses on a more systematic differentiation of such commitments to support international decision making in
Stochastic Effects in Microstructure
Directory of Open Access Journals (Sweden)
Glicksman M.E.
2002-01-01
Full Text Available We are currently studying microstructural responses to diffusion-limited coarsening in two-phase materials. A mathematical solution to late-stage multiparticle diffusion in finite systems is formulated with account taken of particle-particle interactions and their microstructural correlations, or "locales". The transition from finite system behavior to that for an infinite microstructure is established analytically. Large-scale simulations of late-stage phase coarsening dynamics show increased fluctuations with increasing volume fraction, Vv, of the mean flux entering or leaving particles of a given size class. Fluctuations about the mean flux were found to depend on the scaled particle size, R/, where R is the radius of a particle and is the radius of the dispersoid averaged over the population within the microstructure. Specifically, small (shrinking particles tend to display weak fluctuations about their mean flux, whereas particles of average, or above average size, exhibit strong fluctuations. Remarkably, even in cases of microstructures with a relatively small volume fraction (Vv ~ 10-4, the particle size distribution is broader than that for the well-known Lifshitz-Slyozov limit predicted at zero volume fraction. The simulation results reported here provide some additional surprising insights into the effect of diffusion interactions and stochastic effects during evolution of a microstructure, as it approaches its thermodynamic end-state.
Adaptation in stochastic environments
Clark, Colib
1993-01-01
The classical theory of natural selection, as developed by Fisher, Haldane, and 'Wright, and their followers, is in a sense a statistical theory. By and large the classical theory assumes that the underlying environment in which evolution transpires is both constant and stable - the theory is in this sense deterministic. In reality, on the other hand, nature is almost always changing and unstable. We do not yet possess a complete theory of natural selection in stochastic environ ments. Perhaps it has been thought that such a theory is unimportant, or that it would be too difficult. Our own view is that the time is now ripe for the development of a probabilistic theory of natural selection. The present volume is an attempt to provide an elementary introduction to this probabilistic theory. Each author was asked to con tribute a simple, basic introduction to his or her specialty, including lively discussions and speculation. We hope that the book contributes further to the understanding of the roles of "Cha...
Kallianpur, Gopinath; Hida, Takeyuki
1987-01-01
The use of probabilistic methods in the biological sciences has been so well established by now that mathematical biology is regarded by many as a distinct dis cipline with its own repertoire of techniques. The purpose of the Workshop on sto chastic methods in biology held at Nagoya University during the week of July 8-12, 1985, was to enable biologists and probabilists from Japan and the U. S. to discuss the latest developments in their respective fields and to exchange ideas on the ap plicability of the more recent developments in stochastic process theory to problems in biology. Eighteen papers were presented at the Workshop and have been grouped under the following headings: I. Population genetics (five papers) II. Measure valued diffusion processes related to population genetics (three papers) III. Neurophysiology (two papers) IV. Fluctuation in living cells (two papers) V. Mathematical methods related to other problems in biology, epidemiology, population dynamics, etc. (six papers) An important f...
Stochastic partial differential equations
Lototsky, Sergey V
2017-01-01
Taking readers with a basic knowledge of probability and real analysis to the frontiers of a very active research discipline, this textbook provides all the necessary background from functional analysis and the theory of PDEs. It covers the main types of equations (elliptic, hyperbolic and parabolic) and discusses different types of random forcing. The objective is to give the reader the necessary tools to understand the proofs of existing theorems about SPDEs (from other sources) and perhaps even to formulate and prove a few new ones. Most of the material could be covered in about 40 hours of lectures, as long as not too much time is spent on the general discussion of stochastic analysis in infinite dimensions. As the subject of SPDEs is currently making the transition from the research level to that of a graduate or even undergraduate course, the book attempts to present enough exercise material to fill potential exams and homework assignments. Exercises appear throughout and are usually directly connected ...
AA, stochastic precooling kicker
CERN PhotoLab
1980-01-01
The freshly injected antiprotons were subjected to fast stochastic "precooling", while a shutter shielded the deeply cooled antiproton stack from the violent action of the precooling kicker. In this picture, the injection orbit is to the left, the stack orbit to the far right, the separating shutter is in open position. After several seconds of precooling (in momentum and in the vertical plane), the shutter was opened briefly, so that by means of RF the precooled antiprotons could be transferred to the stack tail, where they were subjected to further cooling in momentum and both transverse planes, until they ended up, deeply cooled, in the stack core. The fast shutter, which had to open and close in a fraction of a second was an essential item of the cooling scheme and a mechanical masterpiece. Here the shutter is in the open position. The precooling pickups were of the same design, with the difference that the kickers had cooling circuits and the pickups not. 8401150 shows a precooling pickup with the shutte...
A stochastic framework for clearing of reactive power market
International Nuclear Information System (INIS)
Amjady, N.; Rabiee, A.; Shayanfar, H.A.
2010-01-01
This paper presents a new stochastic framework for clearing of day-ahead reactive power market. The uncertainty of generating units in the form of system contingencies are considered in the reactive power market-clearing procedure by the stochastic model in two steps. The Monte-Carlo Simulation (MCS) is first used to generate random scenarios. Then, in the second step, the stochastic market-clearing procedure is implemented as a series of deterministic optimization problems (scenarios) including non-contingent scenario and different post-contingency states. In each of these deterministic optimization problems, the objective function is total payment function (TPF) of generators which refers to the payment paid to the generators for their reactive power compensation. The effectiveness of the proposed model is examined based on the IEEE 24-bus Reliability Test System (IEEE 24-bus RTS). (author)
Energy Technology Data Exchange (ETDEWEB)
Groenroos, Eija [Helsinki Metropolia University of Applied Sciences, Degree Programme in Radiography and Radiotherapy, Mannerheimintie 172, 00300 Helsinki (Finland)], E-mail: eija.gronroos@metropolia.fi; Pajukari, Arja [MHS, Hus-Roentgen, PL 809, 00029 Hus (Finland)], E-mail: arja.pajukari@hus.fi; Matinheikki-Kokko, Kaija [Helsinki Metropolia University of Applied Sciences, Mannerheimintie 172, 00300 Helsinki (Finland)
2009-11-15
Purpose: The aim of the study is to examine factors associated with the goal commitment of radiography departments' staff. The associations studied are (1) organizational change, (2) work-related factors, (3) psychosocial work environment, and (4) intention to leave. Method: The follow-up study was performed between 2005 and 2007 in co-operation with 10 radiography departments of two Finnish municipalities. In 2005 the response rate was 60% (n = 97/163) and in 2007 it was 49% (n = 73/150). Results: The goal commitment had dropped during the organizational change from 3.96 in 2005 to 3.60 in 2007 (scale 1-5) (p = 0.001). Best predictors for the goal commitment of radiography departments' staff were having children (OR 4.4) and perceiving functional environment clearly (OR 2.6). Correlation between the goal commitment and intention to leave of the staff was -0.32 (p = 0.01). Conclusion: From the viewpoint of the commitment of the radiography departments' staff, the trend of uniting quite independent health care units into larger entities seems not to be beneficial. This study reveals that commitment to one's work unit is most of all a question of stability and job security. This is a fact the leadership of the radiography departments should take into account, appreciate and support to assure the tenure and productivity of their workforce.
International Nuclear Information System (INIS)
Groenroos, Eija; Pajukari, Arja; Matinheikki-Kokko, Kaija
2009-01-01
Purpose: The aim of the study is to examine factors associated with the goal commitment of radiography departments' staff. The associations studied are (1) organizational change, (2) work-related factors, (3) psychosocial work environment, and (4) intention to leave. Method: The follow-up study was performed between 2005 and 2007 in co-operation with 10 radiography departments of two Finnish municipalities. In 2005 the response rate was 60% (n = 97/163) and in 2007 it was 49% (n = 73/150). Results: The goal commitment had dropped during the organizational change from 3.96 in 2005 to 3.60 in 2007 (scale 1-5) (p = 0.001). Best predictors for the goal commitment of radiography departments' staff were having children (OR 4.4) and perceiving functional environment clearly (OR 2.6). Correlation between the goal commitment and intention to leave of the staff was -0.32 (p = 0.01). Conclusion: From the viewpoint of the commitment of the radiography departments' staff, the trend of uniting quite independent health care units into larger entities seems not to be beneficial. This study reveals that commitment to one's work unit is most of all a question of stability and job security. This is a fact the leadership of the radiography departments should take into account, appreciate and support to assure the tenure and productivity of their workforce.
The Impact of Trust on Organization Commitment
Robinson, Kimberly; Stinson, Thomas N. (Technical Monitor)
2002-01-01
As the global economy continues to spawn competitive forces, organizations have sought to become more competitive by cutting costs, eliminating non-value added work, and using more automation. Jobs have become broader and more flexible leading to a leaner workforce with higher-level knowledge and skills and more responsibility for day-to-day decisions. More than ever, organizations depend on employees as the innovators and designers of products and processes and as a source of strategic advantage. Therefore employee commitment among knowledge workers is needed to maintain organizational viability. It would seem that stronger relationships due to greater dependency, involvement, and investment would develop between employers and high-technology workers resulting in more committed employees. However, the opposite has been evidenced as key knowledge workers are changing jobs frequently. This may be due to a perceived lack of commitment by management to its employees. The notion of exchange may dominate the development of organizational commitment whereby an individual decides what to give a firm (commitment, extra effort, better performance, etc.) based on what the firm gives them (e.g., trust and security). It is the relationship between an employee's organizational commitment and the responding level of trust in the organization that is examined in this paper. An experiment is described that will seek to identify this relationship. Preliminary results are expected to show a positive relationship whereby employee commitment is positively correlated with organizational trust.
Stochastic congestion management in power markets using efficient scenario approaches
International Nuclear Information System (INIS)
Esmaili, Masoud; Amjady, Nima; Shayanfar, Heidar Ali
2010-01-01
Congestion management in electricity markets is traditionally performed using deterministic values of system parameters assuming a fixed network configuration. In this paper, a stochastic programming framework is proposed for congestion management considering the power system uncertainties comprising outage of generating units and transmission branches. The Forced Outage Rate of equipment is employed in the stochastic programming. Using the Monte Carlo simulation, possible scenarios of power system operating states are generated and a probability is assigned to each scenario. The performance of the ordinary as well as Lattice rank-1 and rank-2 Monte Carlo simulations is evaluated in the proposed congestion management framework. As a tradeoff between computation time and accuracy, scenario reduction based on the standard deviation of accepted scenarios is adopted. The stochastic congestion management solution is obtained by aggregating individual solutions of accepted scenarios. Congestion management using the proposed stochastic framework provides a more realistic solution compared with traditional deterministic solutions. Results of testing the proposed stochastic congestion management on the 24-bus reliability test system indicate the efficiency of the proposed framework.
Stochastic Synapses Enable Efficient Brain-Inspired Learning Machines
Neftci, Emre O.; Pedroni, Bruno U.; Joshi, Siddharth; Al-Shedivat, Maruan; Cauwenberghs, Gert
2016-01-01
Recent studies have shown that synaptic unreliability is a robust and sufficient mechanism for inducing the stochasticity observed in cortex. Here, we introduce Synaptic Sampling Machines (S2Ms), a class of neural network models that uses synaptic stochasticity as a means to Monte Carlo sampling and unsupervised learning. Similar to the original formulation of Boltzmann machines, these models can be viewed as a stochastic counterpart of Hopfield networks, but where stochasticity is induced by a random mask over the connections. Synaptic stochasticity plays the dual role of an efficient mechanism for sampling, and a regularizer during learning akin to DropConnect. A local synaptic plasticity rule implementing an event-driven form of contrastive divergence enables the learning of generative models in an on-line fashion. S2Ms perform equally well using discrete-timed artificial units (as in Hopfield networks) or continuous-timed leaky integrate and fire neurons. The learned representations are remarkably sparse and robust to reductions in bit precision and synapse pruning: removal of more than 75% of the weakest connections followed by cursory re-learning causes a negligible performance loss on benchmark classification tasks. The spiking neuron-based S2Ms outperform existing spike-based unsupervised learners, while potentially offering substantial advantages in terms of power and complexity, and are thus promising models for on-line learning in brain-inspired hardware. PMID:27445650
Escalation of Commitment in the Surgical ICU.
Braxton, Carla C; Robinson, Celia N; Awad, Samir S
2017-04-01
Escalation of commitment is a business term that describes the continued investment of resources into a project even after there is objective evidence of the project's impending failure. Escalation of commitment may be a contributor to high healthcare costs associated with critically ill patients as it has been shown that, despite almost certain futility, most ICU costs are incurred in the last week of life. Our objective was to determine if escalation of commitment occurs in healthcare settings, specifically in the surgical ICU. We hypothesize that factors previously identified in business and organizational psychology literature including self-justification, accountability, sunk costs, and cognitive dissonance result in escalation of commitment behavior in the surgical ICU setting resulting in increased utilization of resources and cost. A descriptive case study that illustrates common ICU narratives in which escalation of commitment can occur. In addition, we describe factors that are thought to contribute to escalation of commitment behaviors. Escalation of commitment behavior was observed with self-justification, accountability, and cognitive dissonance accounting for the majority of the behavior. Unlike in business decisions, sunk costs was not as evident. In addition, modulating factors such as personality, individual experience, culture, and gender were identified as contributors to escalation of commitment. Escalation of commitment occurs in the surgical ICU, resulting in significant expenditure of resources despite a predicted and often known poor outcome. Recognition of this phenomenon may lead to actions aimed at more rational decision making and may contribute to lowering healthcare costs. Investigation of objective measures that can help aid decision making in the surgical ICU is warranted.
Multi-objective unit commitment problem using Cuckoo search ...
African Journals Online (AJOL)
user
Many solution strategies are available to solve the highly non-smooth problem. ... So, artificial intelligence techniques like, neural ..... For instance, let us assume that the Ton and Toff for a hypothetical thermal power ...... Energy Convers, Vol.
Syncrude's commitment to Aboriginal development
International Nuclear Information System (INIS)
Loader, R. K.
1999-01-01
Syncrude's program designed to maintain good relations with Aboriginal communities in all areas where Syncrude operation impact upon Aboriginal peoples and their traditional ways of life are described. The program extends from employment through education to business and community development, the preservation of traditional lifestyles, and the protection of the environment. As examples, some 13 per cent of Syncrude's workforce is made up of Aboriginal people, at an average annual salary of $58,000. The company offers $ 2,000 each, specifically to Aboriginal persons, wanting to further their education particularly in disciplines related to oil sands. A five-year $ 500,000 program has been established by Syncrude at the University of Alberta specifically for Aboriginal people to pursue careers in engineering, medicine , education and business. Other career programs are also offered through Keyano College, Athabasca University and the Northern Alberta Development Council, and there is a strong commitment by the company to encouraging adults to go back to school and for kids to stay in school. Last year the company spent $ 54 million with Aboriginal-owned and operated businesses; the company also support several programs to foster the appreciation of Aboriginal culture not only in Alberta but throughout the country. Environment is the fifth and final element of the Aboriginal Development Program. It involves consultation and working with local communities on environmental matters involving issues ranging from land reclamation to emission reduction. Some six million dollars are spent annually on reclaiming land and reintroducing native animal and plant species wherever possible. An outstanding example of this is the Wood Bison Trail on 210 hectares of reclaimed land managed by the Fort McKay First Nations. It is readily acknowledged that dealing with Aboriginal concerns has not been an easy road to travel and that there are still many things to do. Nevertheless, there
Collective dose commitments from nuclear power programmes
International Nuclear Information System (INIS)
Beninson, D.
1977-01-01
The concepts of collective dose and collective dose commitment are discussed, particularly regarding their use to compare the relative importance of the exposure from several radiation sources and to predict future annual doses from a continuing practice. The collective dose commitment contributions from occupational exposure and population exposure due to the different components of the nuclear power fuel cycle are evaluated. A special discussion is devoted to exposures delivered over a very long time by released radionuclides of long half-lives and to the use of the incomplete collective dose commitment. The maximum future annual ''per caput'' doses from present and projected nuclear power programmes are estimated
Green Suppliers Network Supply Chain Commitment Form
Online form to show your company desires to be a Green Suppliers Network supply chain. Expresses an intent to: commit to engage at least five suppliers to complete an assessment process within a 12-month period and more.
Organisational commitment and responses to planned ...
African Journals Online (AJOL)
Southern African Business Review Volume 15 Number 3 2011 ... This type of change is said to address surface-level issues and avoids threats to deep- .... instrumentality, and commitment to the organisation based on moral attachment by.
Identification of Determinants of Organizational Commitment and ...
African Journals Online (AJOL)
commitment. In this setting, factors such as the loyalty employees feel are based on a .... Organizational structure characteristics like size span of control, .... working environment (ii) Tools and equipment (iii) Working methods (iv) Security.
JOB ANXIETY, ORGANIZATIONAL COMMITMENT AND JOB ...
African Journals Online (AJOL)
and work experience with job satisfaction. ... were more likely to perceive the appraisal as unfair and inappropriate (Desai and ... Working freedom, salary and fringe benefits are the major factors ..... Men, women and attitudinal commitment:.
Work Engagement, Organizational Commitment, Self Efficacy and ...
African Journals Online (AJOL)
Work engagement, organizational commitment and self-efficacy will create a positive attitude in records ... counseling, effective communication and leadership skills. This study therefore ...... self-efficacy and self-esteem: Toward theoretical and ...
Organisational Commitment, Job Satisfaction and Turnover ...
African Journals Online (AJOL)
This study investigated organisational commitment, job satisfaction and turnover intentions among records management personnel in Ondo State Civil Service, Akure, Nigeria. Simple random sampling technique was used to draw 240 subjects from a population size of 275 records management personnel.
Gauging the Commitment of Clandestine Group Members
National Research Council Canada - National Science Library
Downs, Doneda D
2006-01-01
.... Until a few years ago, most research on individual commitment and organizational cohesion has been based primarily on questionnaires and open observations on groups that desire to be understood...
Stochastic models: theory and simulation.
Energy Technology Data Exchange (ETDEWEB)
Field, Richard V., Jr.
2008-03-01
Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.
Stochastic Still Water Response Model
DEFF Research Database (Denmark)
Friis-Hansen, Peter; Ditlevsen, Ove Dalager
2002-01-01
In this study a stochastic field model for the still water loading is formulated where the statistics (mean value, standard deviation, and correlation) of the sectional forces are obtained by integration of the load field over the relevant part of the ship structure. The objective of the model is...... out that an important parameter of the stochastic cargo field model is the mean number of containers delivered by each customer.......In this study a stochastic field model for the still water loading is formulated where the statistics (mean value, standard deviation, and correlation) of the sectional forces are obtained by integration of the load field over the relevant part of the ship structure. The objective of the model...... is to establish the stochastic load field conditional on a given draft and trim of the vessel. The model contributes to a realistic modelling of the stochastic load processes to be used in a reliability evaluation of the ship hull. Emphasis is given to container vessels. The formulation of the model for obtaining...
Stochastic quantization and topological theories
International Nuclear Information System (INIS)
Fainberg, V.Y.; Subbotin, A.V.; Kuznetsov, A.N.
1992-01-01
In the last two years topological quantum field theories (TQFT) have attached much attention. This paper reports that from the very beginning it was realized that due to a peculiar BRST-like symmetry these models admitted so-called Nicolai mapping: the Nicolai variables, in terms of which actions of the theories become gaussian, are nothing but (anti-) selfduality conditions or their generalizations. This fact became a starting point in the quest of possible stochastic interpretation to topological field theories. The reasons behind were quite simple and included, in particular, the well-known relations between stochastic processes and supersymmetry. The main goal would have been achieved, if it were possible to construct stochastic processes governed by Langevin or Fokker-Planck equations in a real Euclidean time leading to TQFT's path integrals (equivalently: to reformulate TQFTs as non-equilibrium phase dynamics of stochastic processes). Further on, if it would appear that these processes correspond to the stochastic quantization of theories of some definite kind, one could expect (d + 1)-dimensional TQFTs to share some common properties with d-dimensional ones
Stochastic quantization of Einstein gravity
International Nuclear Information System (INIS)
Rumpf, H.
1986-01-01
We determine a one-parameter family of covariant Langevin equations for the metric tensor of general relativity corresponding to DeWitt's one-parameter family of supermetrics. The stochastic source term in these equations can be expressed in terms of a Gaussian white noise upon the introduction of a stochastic tetrad field. The only physically acceptable resolution of a mathematical ambiguity in the ansatz for the source term is the adoption of Ito's calculus. By taking the formal equilibrium limit of the stochastic metric a one-parameter family of covariant path-integral measures for general relativity is obtained. There is a unique parameter value, distinguished by any one of the following three properties: (i) the metric is harmonic with respect to the supermetric, (ii) the path-integral measure is that of DeWitt, (iii) the supermetric governs the linearized Einstein dynamics. Moreover the Feynman propagator corresponding to this parameter is causal. Finally we show that a consistent stochastic perturbation theory gives rise to a new type of diagram containing ''stochastic vertices.''
2011-08-12
...., subsidies, standards and technical regulations, sanitary and phytosanitary measures, government procurement... Concerning China's Compliance With WTO Commitments AGENCY: Office of the United States Trade Representative. ACTION: Request for comments and notice of public hearing concerning China's compliance with its WTO...
Competency management: Balancing between commitment and control
Heinsman, Hanneke; de Hoogh, Annebel H. B.; Koopman, Paul L.; van Muijen, Jaap J.
2006-01-01
This study investigated the relationships between commitment and control approaches and the use of competency management by adopting the theory of planned behavior. Questionnaires were filled out by 43 human resource experts working in different organizations. We expected components of the theory of planned behavior to mediate the relationship between commitment and control approaches and the use of competency management (behavior). Regression analysis showed that perceived behavioral control...
COMMITMENT A Psychological Tie and Moral Value
2017-04-01
Research When I think of commitment, it is a feeling and an action with a strong moral component. However, as I began researching commitment it became...characteristics of “being committed” must be independent of behavior. One mechanism of doing this is through the analysis of bargaining and side bets .27...Becker uses Schelling’s example of bargaining to buy a house to explain side bets . In this scenario, you offer $16,000, but the seller counters with
Quantum bit commitment with misaligned reference frames
International Nuclear Information System (INIS)
Harrow, Aram; Oliveira, Roberto; Terhal, Barbara M.
2006-01-01
Suppose that Alice and Bob define their coordinate axes differently, and the change of reference frame between them is given by a probability distribution μ over SO(3). We show that this uncertainty of reference frame is of no use for bit commitment when μ is uniformly distributed over a (sub)group of SO(3), but other choices of μ can give rise to a partially or even arbitrarily secure bit commitment
Stochastic Approaches Within a High Resolution Rapid Refresh Ensemble
Jankov, I.
2017-12-01
It is well known that global and regional numerical weather prediction (NWP) ensemble systems are under-dispersive, producing unreliable and overconfident ensemble forecasts. Typical approaches to alleviate this problem include the use of multiple dynamic cores, multiple physics suite configurations, or a combination of the two. While these approaches may produce desirable results, they have practical and theoretical deficiencies and are more difficult and costly to maintain. An active area of research that promotes a more unified and sustainable system is the use of stochastic physics. Stochastic approaches include Stochastic Parameter Perturbations (SPP), Stochastic Kinetic Energy Backscatter (SKEB), and Stochastic Perturbation of Physics Tendencies (SPPT). The focus of this study is to assess model performance within a convection-permitting ensemble at 3-km grid spacing across the Contiguous United States (CONUS) using a variety of stochastic approaches. A single physics suite configuration based on the operational High-Resolution Rapid Refresh (HRRR) model was utilized and ensemble members produced by employing stochastic methods. Parameter perturbations (using SPP) for select fields were employed in the Rapid Update Cycle (RUC) land surface model (LSM) and Mellor-Yamada-Nakanishi-Niino (MYNN) Planetary Boundary Layer (PBL) schemes. Within MYNN, SPP was applied to sub-grid cloud fraction, mixing length, roughness length, mass fluxes and Prandtl number. In the RUC LSM, SPP was applied to hydraulic conductivity and tested perturbing soil moisture at initial time. First iterative testing was conducted to assess the initial performance of several configuration settings (e.g. variety of spatial and temporal de-correlation lengths). Upon selection of the most promising candidate configurations using SPP, a 10-day time period was run and more robust statistics were gathered. SKEB and SPPT were included in additional retrospective tests to assess the impact of using
Interpersonal Conflict and Organizational Commitment Among Licensed Practical Nurses.
Loes, Chad N; Tobin, Mary B
The shortage of nursing professionals in the United States is unquestionable. This shortage, which is predicted to continue into the foreseeable future, is a particularly salient problem within the nursing profession. This is especially true for long-term care facility administrators who not only are faced with the challenge of increasing numbers of aging residents but also regularly struggle with turnover among more cost-effective nursing staff, such as licensed practical nurses (LPNs). The primary purpose of this study was to examine whether perceived interpersonal conflict influences organizational commitment among LPNs. To accomplish this, we analyzed responses from 1165 LPNs throughout a Midwestern state who were queried on their perceptions of interpersonal conflict and organizational commitment in their work settings. Considering a wide range of potential confounding influences such as age and years working as an LPN, for example, we found that higher perceived interpersonal conflict was associated with significantly lower levels of organizational commitment. The implications of these findings, along with recommendations for nurse administrators to reduce LPN turnover, are discussed in the article.
Meaningful work, work engagement and organisational commitment
Directory of Open Access Journals (Sweden)
Madelyn Geldenhuys
2014-03-01
Research purpose: The aim of the study was to investigate the relationships amongst psychological meaningfulness, work engagement and organisational commitment and to test for a possible mediation effect of work engagement on the relationship between psychological meaningfulness and organisational commitment. Motivation for the study: Managers have to rethink ways of improving productivity and performance at work, due to the diverse, and in some instances escalating, needs of employees (e.g. financial support to uphold their interest in and enjoyment of working. Research approach, design and method: A quantitative approach was employed to gather the data for the study, utilising a cross-sectional survey design. The sample (n = 415 consisted of working employees from various companies and positions in Gauteng, South Africa. Main findings: The results confirmed a positive relationship between psychological meaningfulness, work engagement and organisational commitment. Further, psychological meaningfulness predicts work engagement, whilst psychological meaningfulness and work engagement predict organisational commitment. Practical/managerial implications: Employers identifying their employees’ commitment patterns and mapping out strategies for enhancing those that are relevant to organisational goals will yield positive work outcomes (e.g. employees who are creative, seek growth or challenges for themselves. Contribution/value-add: This study contributes to the literature through highlighting the impact that meaningful work has on sustaining employee commitment to the organisation.
Commitment and Switching Intentions: Customers and Brands
Directory of Open Access Journals (Sweden)
Juliana Werneck Rodrigues
2012-12-01
Full Text Available This study aims to evaluate the relationship between a customer’s brand switching intentions and his commitment to a brand. Based on a literature review, constructs related to customer brand commitment were identified (affective and continuance commitment, trust, satisfaction, switching costs and alternative attractiveness and their roles in the formation of brand switching intentions hypothesized. Through a cross-sectional survey, a sample of 201 smartphone users was collected to test the proposed relationships. Data analysis was carried out via structural equations modeling, with direct effects of trust, satisfaction, switching costs and alternative attractiveness upon the different kinds of commitment being verified. Furthermore, both types of brand commitment (affective and continuance were found to negatively impact a customer’s intention to switch brands. Regarding enterprise customer strategies, the research findings suggest that, if firms are able to track customer brand commitment, they could use such knowledge to develop better relationship strategies, minimizing customer defection and further developing customer value to the company.
The Artistic Commitment of Kenyon Cox: An American Neoclassical Artist
SMITH, Marc S.
2016-01-01
At the end of the nineteenth century, the United States had undergone deep transformations. The second Industrial Revolution had created huge amounts of new wealth and power. This led to an alteration of the urban social fabric and to a repositioning of the country on the international scene.Since the 1870s, the American Renaissance had been a vehicle for the diffusion of new values and new concepts. As a broad neoclassical movement in the arts, it was committed to a rewriting of the country’...
Campo, M. A.; Lopez, J. J.; Rebole, J. P.
2012-04-01
This work was carried out in north of Spain. San Sebastian A meteorological station, where there are available precipitation records every ten minutes was selected. Precipitation data covers from October of 1927 to September of 1997. Pulse models describe the temporal process of rainfall as a succession of rainy cells, main storm, whose origins are distributed in time according to a Poisson process and a secondary process that generates a random number of cells of rain within each storm. Among different pulse models, the Bartlett-Lewis was used. On the other hand, alternative renewal processes and Markov chains describe the way in which the process will evolve in the future depending only on the current state. Therefore they are nor dependant on past events. Two basic processes are considered when describing the occurrence of rain: the alternation of wet and dry periods and temporal distribution of rainfall in each rain event, which determines the rainwater collected in each of the intervals that make up the rain. This allows the introduction of alternative renewal processes and Markov chains of three states, where interstorm time is given by either of the two dry states, short or long. Thus, the stochastic model of Markov chains tries to reproduce the basis of pulse models: the succession of storms, each one composed for a series of rain, separated by a short interval of time without theoretical complexity of these. In a first step, we analyzed all variables involved in the sequential process of the rain: rain event duration, event duration of non-rain, average rainfall intensity in rain events, and finally, temporal distribution of rainfall within the rain event. Additionally, for pulse Bartlett-Lewis model calibration, main descriptive statistics were calculated for each month, considering the process of seasonal rainfall in each month. In a second step, both models were calibrated. Finally, synthetic series were simulated with calibration parameters; series
Stacking with stochastic cooling
Energy Technology Data Exchange (ETDEWEB)
Caspers, Fritz E-mail: Fritz.Caspers@cern.ch; Moehl, Dieter
2004-10-11
Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 10{sup 5} the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some
Stochastic models of cell motility
DEFF Research Database (Denmark)
Gradinaru, Cristian
2012-01-01
Cell motility and migration are central to the development and maintenance of multicellular organisms, and errors during this process can lead to major diseases. Consequently, the mechanisms and phenomenology of cell motility are currently under intense study. In recent years, a new...... interdisciplinary field focusing on the study of biological processes at the nanoscale level, with a range of technological applications in medicine and biological research, has emerged. The work presented in this thesis is at the interface of cell biology, image processing, and stochastic modeling. The stochastic...... models introduced here are based on persistent random motion, which I apply to real-life studies of cell motility on flat and nanostructured surfaces. These models aim to predict the time-dependent position of cell centroids in a stochastic manner, and conversely determine directly from experimental...
Stochastic Modelling of Hydrologic Systems
DEFF Research Database (Denmark)
Jonsdottir, Harpa
2007-01-01
In this PhD project several stochastic modelling methods are studied and applied on various subjects in hydrology. The research was prepared at Informatics and Mathematical Modelling at the Technical University of Denmark. The thesis is divided into two parts. The first part contains...... an introduction and an overview of the papers published. Then an introduction to basic concepts in hydrology along with a description of hydrological data is given. Finally an introduction to stochastic modelling is given. The second part contains the research papers. In the research papers the stochastic methods...... are described, as at the time of publication these methods represent new contribution to hydrology. The second part also contains additional description of software used and a brief introduction to stiff systems. The system in one of the papers is stiff....
Stochastic quantization of general relativity
International Nuclear Information System (INIS)
Rumpf, H.
1986-01-01
Following an elementary exposition of the basic mathematical concepts used in the theory of stochastic relaxation processes the stochastic quantization method of Parisi and Wu is briefly reviewed. The method is applied to Einstein's theory of gravitation using a formalism that is manifestly covariant with respect to field redefinitions. This requires the adoption of Ito's calculus and the introduction of a metric in field configuration space, for which there is a unique candidate. Due to the indefiniteness of the Euclidean Einstein-Hilbert action stochastic quantization is generalized to the pseudo-Riemannian case. It is formally shown to imply the DeWitt path integral measure. Finally a new type of perturbation theory is developed. (Author)
Applied probability and stochastic processes
Sumita, Ushio
1999-01-01
Applied Probability and Stochastic Processes is an edited work written in honor of Julien Keilson. This volume has attracted a host of scholars in applied probability, who have made major contributions to the field, and have written survey and state-of-the-art papers on a variety of applied probability topics, including, but not limited to: perturbation method, time reversible Markov chains, Poisson processes, Brownian techniques, Bayesian probability, optimal quality control, Markov decision processes, random matrices, queueing theory and a variety of applications of stochastic processes. The book has a mixture of theoretical, algorithmic, and application chapters providing examples of the cutting-edge work that Professor Keilson has done or influenced over the course of his highly-productive and energetic career in applied probability and stochastic processes. The book will be of interest to academic researchers, students, and industrial practitioners who seek to use the mathematics of applied probability i...
Stochastic carbon sinks for combating carbon dioxide emissions in the EU
International Nuclear Information System (INIS)
Gren, Ing-Marie; Carlsson, Mattias; Elofsson, Katarina; Munnich, Miriam
2012-01-01
This paper carries out numerical calculations on the potential of carbon sinks in the EU Emissions Trading Scheme (ETS) and national commitments under conditions of stochastic carbon dioxide emissions from fossil fuels and carbon sequestration by forests. Chance constraint programming is used to analyze the role of stochastic carbon sinks for national and EU-wide compliance costs. The analytical results show that the inclusion of the carbon sink option can reduce costs for low enough marginal cost and risk discount, but also that costless carbon sinks as by-products from forestry are not part of a cost-effective solution under a high reliability concern. Cost savings are reduced due to risk discounting under a reliability concern, in particular when assigning Chebyshev's inequality as compared with a normal probability distribution. It is also shown that the supply of forest sinks on the market depends on the differences in marginal abatement cost between the trading and the non-trading sectors, and in risk discounting between achievements of the ETS cap and the national commitment. Relatively low marginal abatement cost in the non-trading sector and high risk discounting of national commitment achievements increase the supply of sinks in the market and, hence, reduces the equilibrium price. The empirical application illustrates the importance of risk discounting for the magnitude of cost savings obtained from introducing forest carbon sinks in the EU ETS and national commitments.
Directory of Open Access Journals (Sweden)
Marnis Atmojo
2012-04-01
Full Text Available This research has four main objectives; first, to prove and analyze the influence of transformational leadership towards employee job satis faction; Second, to prove and analyze the influence of transformational leadership towards organizational commitment; Third, to prove and analyze the influence of transformationalleadership towards employee performance; Fourth, to prove and analyze the influence of organization commitment towards the employee performance. This research involved 146 members of middle management as our research sample namely Head of Department, Plantation Manager, Plant Manager, Head of Bureau/Division, Head Assistant, Head of Strategic Business Unit (SBU, Chief Engineer and Head of Hospital Service. Structural Equation Modeling (SEM was used to test and analyze relationship among the research variables. Research findings are transformational leadership significantly influences job satisfaction, transformational leadership significantly influences the organization commitment. The job satisfaction is shown to have significant influence on employee performance, and organization commitment significantly influences the employee performance.
Organizational commitment of a health profession faculty: dimensions, correlates and conditions.
Marchiori, Dennis M; Henkin, Alan B
2004-06-01
Health professions depend on their faculties to prepare new practitioners, conduct research and provide essential services. Organizational commitment is an important aspect of faculty effectiveness and job performance, and may impact on turnover, absenteeism and interpersonal trust. A survey of organizational commitment, including faculty demographics and workplace variables, was conducted. Respondents were full- and part-time chiropractic faculty working in the United States and Canada. More than 54% of the study population (n = 609) completed and returned the instrument. A large majority of the respondents were male (68.4%) and employed full-time (81.6%). Almost half (47.5%) of the respondents were assigned to the area of patient care at their institutions. This study provides an initial assessment of organizational commitment among chiropractic faculty. Tenure in higher education, gender and age were found to be the most important predictors of organizational commitment.
Stochastic geometry for image analysis
Descombes, Xavier
2013-01-01
This book develops the stochastic geometry framework for image analysis purpose. Two main frameworks are described: marked point process and random closed sets models. We derive the main issues for defining an appropriate model. The algorithms for sampling and optimizing the models as well as for estimating parameters are reviewed. Numerous applications, covering remote sensing images, biological and medical imaging, are detailed. This book provides all the necessary tools for developing an image analysis application based on modern stochastic modeling.
Stochastic methods in quantum mechanics
Gudder, Stanley P
2005-01-01
Practical developments in such fields as optical coherence, communication engineering, and laser technology have developed from the applications of stochastic methods. This introductory survey offers a broad view of some of the most useful stochastic methods and techniques in quantum physics, functional analysis, probability theory, communications, and electrical engineering. Starting with a history of quantum mechanics, it examines both the quantum logic approach and the operational approach, with explorations of random fields and quantum field theory.The text assumes a basic knowledge of fun
STOCHASTIC METHODS IN RISK ANALYSIS
Directory of Open Access Journals (Sweden)
Vladimíra OSADSKÁ
2017-06-01
Full Text Available In this paper, we review basic stochastic methods which can be used to extend state-of-the-art deterministic analytical methods for risk analysis. We can conclude that the standard deterministic analytical methods highly depend on the practical experience and knowledge of the evaluator and therefore, the stochastic methods should be introduced. The new risk analysis methods should consider the uncertainties in input values. We present how large is the impact on the results of the analysis solving practical example of FMECA with uncertainties modelled using Monte Carlo sampling.
Stochastic dynamics of new inflation
International Nuclear Information System (INIS)
Nakao, Ken-ichi; Nambu, Yasusada; Sasaki, Misao.
1988-07-01
We investigate thoroughly the dynamics of an inflation-driving scalar field in terms of an extended version of the stochastic approach proposed by Starobinsky and discuss the spacetime structure of the inflationary universe. To avoid any complications which might arise due to quantum gravity, we concentrate our discussions on the new inflationary universe scenario in which all the energy scales involved are well below the planck mass. The investigation is done both analytically and numerically. In particular, we present a full numerical analysis of the stochastic scalar field dynamics on the phase space. Then implications of the results are discussed. (author)
Stochastic mechanics and quantum theory
International Nuclear Information System (INIS)
Goldstein, S.
1987-01-01
Stochastic mechanics may be regarded as both generalizing classical mechanics to processes with intrinsic randomness, as well as providing the sort of detailed description of microscopic events declared impossible under the traditional interpretation of quantum mechanics. It avoids the many conceptual difficulties which arise from the assumption that quantum mechanics, i.e., the wave function, provides a complete description of (microscopic) physical reality. Stochastic mechanics presents a unified treatment of the microscopic and macroscopic domains, in which the process of measurement plays no special physical role and which reduces to Newtonian mechanics in the macroscopic limit
Probability, Statistics, and Stochastic Processes
Olofsson, Peter
2011-01-01
A mathematical and intuitive approach to probability, statistics, and stochastic processes This textbook provides a unique, balanced approach to probability, statistics, and stochastic processes. Readers gain a solid foundation in all three fields that serves as a stepping stone to more advanced investigations into each area. This text combines a rigorous, calculus-based development of theory with a more intuitive approach that appeals to readers' sense of reason and logic, an approach developed through the author's many years of classroom experience. The text begins with three chapters that d
QB1 - Stochastic Gene Regulation
Energy Technology Data Exchange (ETDEWEB)
Munsky, Brian [Los Alamos National Laboratory
2012-07-23
Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.
Stochastic geometry and its applications
Chiu, Sung Nok; Kendall, Wilfrid S; Mecke, Joseph
2013-01-01
An extensive update to a classic text Stochastic geometry and spatial statistics play a fundamental role in many modern branches of physics, materials sciences, engineering, biology and environmental sciences. They offer successful models for the description of random two- and three-dimensional micro and macro structures and statistical methods for their analysis. The previous edition of this book has served as the key reference in its field for over 18 years and is regarded as the best treatment of the subject of stochastic geometry, both as a subject with vital a
Algebraic and stochastic coding theory
Kythe, Dave K
2012-01-01
Using a simple yet rigorous approach, Algebraic and Stochastic Coding Theory makes the subject of coding theory easy to understand for readers with a thorough knowledge of digital arithmetic, Boolean and modern algebra, and probability theory. It explains the underlying principles of coding theory and offers a clear, detailed description of each code. More advanced readers will appreciate its coverage of recent developments in coding theory and stochastic processes. After a brief review of coding history and Boolean algebra, the book introduces linear codes, including Hamming and Golay codes.
Stochastic and infinite dimensional analysis
Carpio-Bernido, Maria; Grothaus, Martin; Kuna, Tobias; Oliveira, Maria; Silva, José
2016-01-01
This volume presents a collection of papers covering applications from a wide range of systems with infinitely many degrees of freedom studied using techniques from stochastic and infinite dimensional analysis, e.g. Feynman path integrals, the statistical mechanics of polymer chains, complex networks, and quantum field theory. Systems of infinitely many degrees of freedom create their particular mathematical challenges which have been addressed by different mathematical theories, namely in the theories of stochastic processes, Malliavin calculus, and especially white noise analysis. These proceedings are inspired by a conference held on the occasion of Prof. Ludwig Streit’s 75th birthday and celebrate his pioneering and ongoing work in these fields.
A Fractionally Integrated Wishart Stochastic Volatility Model
M. Asai (Manabu); M.J. McAleer (Michael)
2013-01-01
textabstractThere has recently been growing interest in modeling and estimating alternative continuous time multivariate stochastic volatility models. We propose a continuous time fractionally integrated Wishart stochastic volatility (FIWSV) process. We derive the conditional Laplace transform of
Exact Algorithms for Solving Stochastic Games
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt; Koucky, Michal; Lauritzen, Niels
2012-01-01
Shapley's discounted stochastic games, Everett's recursive games and Gillette's undiscounted stochastic games are classical models of game theory describing two-player zero-sum games of potentially infinite duration. We describe algorithms for exactly solving these games....
Transport properties of stochastic Lorentz models
Beijeren, H. van
Diffusion processes are considered for one-dimensional stochastic Lorentz models, consisting of randomly distributed fixed scatterers and one moving light particle. In waiting time Lorentz models the light particle makes instantaneous jumps between scatterers after a stochastically distributed
Theory, technology, and technique of stochastic cooling
International Nuclear Information System (INIS)
Marriner, J.
1993-10-01
The theory and technological implementation of stochastic cooling is described. Theoretical and technological limitations are discussed. Data from existing stochastic cooling systems are shown to illustrate some useful techniques
Hamidi, Yadollah; Mohammadibakhsh, Roghayeh; Soltanian, Alireza; Behzadifar, Masoud
2017-01-01
Presence of committed personnel in each organization not only reduces their absenteeism, delays, and displacements but also leads to a dramatic increase in performance and efficiency of an organization, mental freshness of employees, better manifestation of noble objectives, and organizational mission as well as fulfillment of personal goals. Therefore, the purpose of this study was to determine the relationship between organizational culture and organizational commitment of employees in administrative units of health care centers in the cities of Hamedan Province based on the Denison model in 2015. In this cross-sectional study, 177 employees in administrative units of health care centers in the cities of Hamedan Province were selected by a multistage stratified sampling method. The data collection instruments included the standardized Denison organizational culture survey and organizational commitment questionnaire by Meyer and Allen. Data were analyzed by IBM-SPSS version 21 using descriptive statistics and Pearson product-moment coefficient. Among the 12 indicators of organizational culture, the highest mean scores were assigned to empowerment (16.74), organizational learning (16.41), vision (16.4), and strategic direction (16.35); respectively. Furthermore, the indicators of capability development (14.2), core values (15.31), team orientation (15.45), and goals (15.46) received the lowest mean scores in this respect. Among the four dimensions of organizational culture, the highest mean score was related to "mission" in organizational culture and the lowest score was associated with "involvement." Meyer and Allen's organizational commitment model also had three components in which affective commitment in this study obtained the highest score (26.63) and continuance commitment received the lowest score (24.73). In this study, there was a significant correlation between all the components of organizational culture and organizational commitment of employees in
Stochastic modeling and analysis of telecoms networks
Decreusefond, Laurent
2012-01-01
This book addresses the stochastic modeling of telecommunication networks, introducing the main mathematical tools for that purpose, such as Markov processes, real and spatial point processes and stochastic recursions, and presenting a wide list of results on stability, performances and comparison of systems.The authors propose a comprehensive mathematical construction of the foundations of stochastic network theory: Markov chains, continuous time Markov chains are extensively studied using an original martingale-based approach. A complete presentation of stochastic recursions from an
Dynamical and hamiltonian dilations of stochastic processes
International Nuclear Information System (INIS)
Baumgartner, B.; Gruemm, H.-R.
1982-01-01
This is a study of the problem, which stochastic processes could arise from dynamical systems by loss of information. The notions of ''dilation'' and ''approximate dilation'' of a stochastic process are introduced to give exact definitions of this particular relationship. It is shown that every generalized stochastic process is approximately dilatable by a sequence of dynamical systems, but for stochastic processes in full generality one needs nets. (Author)
2013-01-08
... EXPORT-IMPORT BANK OF THE UNITED STATES [Public Notice 2012-0558] Application for Final Commitment...-Import Bank of the United States. ACTION: Notice. SUMMARY: This Notice is to inform the public, in accordance with Section 3(c)(10) of the Charter of the Export-Import Bank of the United States (``Ex-Im Bank...
Environmental vs Demographic Stochasticity in Population Growth
Braumann, C. A.
2010-01-01
Compares the effect on population growth of envinonmental stochasticity (random environmental variations described by stochastic differential equations) with demographic stochasticity (random variations in births and deaths described by branching processes and birth-and-death processes), in the density-independent and the density-dependent cases.
Stochastic diffusion models for substitutable technological innovations
Wang, L.; Hu, B.; Yu, X.
2004-01-01
Based on the analysis of firms' stochastic adoption behaviour, this paper first points out the necessity to build more practical stochastic models. And then, stochastic evolutionary models are built for substitutable innovation diffusion system. Finally, through the computer simulation of the
Does smoking cannabis affect work commitment?
Hyggen, Christer
2012-07-01
This study aimed to examine the associations between cannabis use and work commitment. We used a 25-year panel survey initiated in 1985 with follow-ups in 1987, 1989, 1993, 2003 and 2010. Registered data from a range of public registers were matched with individual responses for the entire period. The panel survey was a nation-wide study set in Norway. A total of 1997 respondents born between 1965 and 1968 were included in the panel. Work involvement scale (WIS) was used to assess work commitment. Involvement with cannabis was based on self-reported smoking of cannabis within the last 12 months and exposure to cannabis through friends. This information was categorized into 'abstaining', 'exposed', 'experimented' and 'involved'. Control measures included socio-economic background, mental health (HSCL-10), education, work satisfaction, unemployment, receipt of social assistance, consumption of alcohol, alcohol-related problems and use of other illicit drugs. The level of work commitment was associated with involvement with cannabis. In 1993, when the respondents were in their mid-20s, those who were involved or had experimented with cannabis displayed lower levels of work commitment than those who were abstaining or merely exposed to cannabis through friends (P labour market experiences, mental health and family characteristics (P Norway the use of cannabis is associated with a reduction in work commitment among adults. © 2012 The Author, Addiction © 2012 Society for the Study of Addiction.
On stochastic differential equations with random delay
International Nuclear Information System (INIS)
Krapivsky, P L; Luck, J M; Mallick, K
2011-01-01
We consider stochastic dynamical systems defined by differential equations with a uniform random time delay. The latter equations are shown to be equivalent to deterministic higher-order differential equations: for an nth-order equation with random delay, the corresponding deterministic equation has order n + 1. We analyze various examples of dynamical systems of this kind, and find a number of unusual behaviors. For instance, for the harmonic oscillator with random delay, the energy grows as exp((3/2) t 2/3 ) in reduced units. We then investigate the effect of introducing a discrete time step ε. At variance with the continuous situation, the discrete random recursion relations thus obtained have intrinsic fluctuations. The crossover between the fluctuating discrete problem and the deterministic continuous one as ε goes to zero is studied in detail on the example of a first-order linear differential equation
Stochastic first passage time accelerated with CUDA
Pierro, Vincenzo; Troiano, Luigi; Mejuto, Elena; Filatrella, Giovanni
2018-05-01
The numerical integration of stochastic trajectories to estimate the time to pass a threshold is an interesting physical quantity, for instance in Josephson junctions and atomic force microscopy, where the full trajectory is not accessible. We propose an algorithm suitable for efficient implementation on graphical processing unit in CUDA environment. The proposed approach for well balanced loads achieves almost perfect scaling with the number of available threads and processors, and allows an acceleration of about 400× with a GPU GTX980 respect to standard multicore CPU. This method allows with off the shell GPU to challenge problems that are otherwise prohibitive, as thermal activation in slowly tilted potentials. In particular, we demonstrate that it is possible to simulate the switching currents distributions of Josephson junctions in the timescale of actual experiments.
Perturbation theory from stochastic quantization
International Nuclear Information System (INIS)
Hueffel, H.
1984-01-01
By using a diagrammatical method it is shown that in scalar theories the stochastic quantization method of Parisi and Wu gives the usual perturbation series in Feynman diagrams. It is further explained how to apply the diagrammatical method to gauge theories, discussing the origin of ghost effects. (Author)
Stochastic Modelling of River Geometry
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Schaarup-Jensen, K.
1996-01-01
Numerical hydrodynamic river models are used in a large number of applications to estimate critical events for rivers. These estimates are subject to a number of uncertainties. In this paper, the problem to evaluate these estimates using probabilistic methods is considered. Stochastic models for ...... for river geometries are formulated and a coupling between hydraulic computational methods and numerical reliability methods is presented....
Stochastic Processes in Epidemic Theory
Lefèvre, Claude; Picard, Philippe
1990-01-01
This collection of papers gives a representative cross-selectional view of recent developments in the field. After a survey paper by C. Lefèvre, 17 other research papers look at stochastic modeling of epidemics, both from a theoretical and a statistical point of view. Some look more specifically at a particular disease such as AIDS, malaria, schistosomiasis and diabetes.
Stochastic theory of grain growth
International Nuclear Information System (INIS)
Hu Haiyun; Xing Xiusan.
1990-11-01
The purpose of this note is to set up a stochastic theory of grain growth and to derive the statistical distribution function and the average value of the grain radius so as to match them with the experiment further. 8 refs, 1 fig
Stochastic vehicle routing with recourse
DEFF Research Database (Denmark)
Gørtz, Inge Li; Nagarajan, Viswanath; Saket, Rishi
2012-01-01
instantiations, a recourse route is computed - but costs here become more expensive by a factor λ. We present an O(log2n ·log(nλ))-approximation algorithm for this stochastic routing problem, under arbitrary distributions. The main idea in this result is relating StochVRP to a special case of submodular...
Universality in stochastic exponential growth.
Iyer-Biswas, Srividya; Crooks, Gavin E; Scherer, Norbert F; Dinner, Aaron R
2014-07-11
Recent imaging data for single bacterial cells reveal that their mean sizes grow exponentially in time and that their size distributions collapse to a single curve when rescaled by their means. An analogous result holds for the division-time distributions. A model is needed to delineate the minimal requirements for these scaling behaviors. We formulate a microscopic theory of stochastic exponential growth as a Master Equation that accounts for these observations, in contrast to existing quantitative models of stochastic exponential growth (e.g., the Black-Scholes equation or geometric Brownian motion). Our model, the stochastic Hinshelwood cycle (SHC), is an autocatalytic reaction cycle in which each molecular species catalyzes the production of the next. By finding exact analytical solutions to the SHC and the corresponding first passage time problem, we uncover universal signatures of fluctuations in exponential growth and division. The model makes minimal assumptions, and we describe how more complex reaction networks can reduce to such a cycle. We thus expect similar scalings to be discovered in stochastic processes resulting in exponential growth that appear in diverse contexts such as cosmology, finance, technology, and population growth.
Stochastic control of traffic patterns
DEFF Research Database (Denmark)
Gaididei, Yuri B.; Gorria, Carlos; Berkemer, Rainer
2013-01-01
A stochastic modulation of the safety distance can reduce traffic jams. It is found that the effect of random modulation on congestive flow formation depends on the spatial correlation of the noise. Jam creation is suppressed for highly correlated noise. The results demonstrate the advantage of h...
The fermion stochastic calculus I
International Nuclear Information System (INIS)
Streater, R.F.
1984-01-01
The author describes the stochastic calculus of quantum processes with fermions. After a description of the Clifford algebra as the csup(*)-algebra generated by spinor fields the damped harmonic oscillator with quantum noise is considered as example. Then the Clifford process is described. Finally the Ito-Clifford integral and the Ito-Clifford isometry are presented. (HSI)
Stochastic and Chaotic Relaxation Oscillations
Grasman, J.; Roerdink, J.B.T.M.
1988-01-01
For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a
Stochastic processes in mechanical engineering
Brouwers, J.J.H.
2006-01-01
Stochastic or random vibrations occur in a variety of applications of mechanicalengineering. Examples are: the dynamics of a vehicle on an irregular roadsurface; the variation in time of thermodynamic variables in municipal wasteincinerators due to fluctuations in heating value of the waste; the
Testing for Stochastic Dominance Efficiency
G.T. Post (Thierry); O. Linton; Y-J. Whang
2005-01-01
textabstractWe propose a new test of the stochastic dominance efficiency of a given portfolio over a class of portfolios. We establish its null and alternative asymptotic properties, and define a method for consistently estimating critical values. We present some numerical evidence that our
Network Analysis with Stochastic Grammars
2015-09-17
rules N = 0 //non-terminal index clusters = cluster(W) //number of clusters drive the number S productions //cluster function described in text...Essa, “Recognizing multitasked activities from video using stochastic context-free grammar,” AAAI/IAAI, pp. 770–776, 2002. [18] R. Nevatia, T. Zhao
Stochastic Volatility and DSGE Models
DEFF Research Database (Denmark)
Andreasen, Martin Møller
This paper argues that a specification of stochastic volatility commonly used to analyze the Great Moderation in DSGE models may not be appropriate, because the level of a process with this specification does not have conditional or unconditional moments. This is unfortunate because agents may...
American options under stochastic volatility
Chockalingam, A.; Muthuraman, K.
2011-01-01
The problem of pricing an American option written on an underlying asset with constant price volatility has been studied extensively in literature. Real-world data, however, demonstrate that volatility is not constant, and stochastic volatility models are used to account for dynamic volatility
Stochastic cooling system in COSY
International Nuclear Information System (INIS)
Brittner, P.; Hacker, H.U.; Prasuhn, D.; Schug, G.; Singer, H.; Spiess, W.; Stassen, R.
1994-01-01
The stochastic cooler system in COSY is designed for proton kinetic energies between 0.8 and 2.5 GeV. Fabrication of the mechanical parts of the system is going on. Test results of the prototype measurements as well as data of the active RF-compontens are presented. (orig.)
Stochastic cooling system in COSY
Energy Technology Data Exchange (ETDEWEB)
Brittner, P [Forschungszentrum Juelich GmbH (Germany); Hacker, H U [Forschungszentrum Juelich GmbH (Germany); Prasuhn, D [Forschungszentrum Juelich GmbH (Germany); Schug, G [Forschungszentrum Juelich GmbH (Germany); Singer, H [Forschungszentrum Juelich GmbH (Germany); Spiess, W [Forschungszentrum Juelich GmbH (Germany); Stassen, R [Forschungszentrum Juelich GmbH (Germany)
1994-09-01
The stochastic cooler system in COSY is designed for proton kinetic energies between 0.8 and 2.5 GeV. Fabrication of the mechanical parts of the system is going on. Test results of the prototype measurements as well as data of the active RF-compontens are presented. (orig.)
Stochastic-field cavitation model
International Nuclear Information System (INIS)
Dumond, J.; Magagnato, F.; Class, A.
2013-01-01
Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian “particles” or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations
Stochastic-field cavitation model
Dumond, J.; Magagnato, F.; Class, A.
2013-07-01
Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian "particles" or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.
Distance covariance for stochastic processes
DEFF Research Database (Denmark)
Matsui, Muneya; Mikosch, Thomas Valentin; Samorodnitsky, Gennady
2017-01-01
The distance covariance of two random vectors is a measure of their dependence. The empirical distance covariance and correlation can be used as statistical tools for testing whether two random vectors are independent. We propose an analog of the distance covariance for two stochastic processes...
Bogler, Ronit; Somech, Anit
2004-01-01
The present study focuses on the relationship between teacher empowerment and teachers' organizational commitment, professional commitment (PC) and organizational citizenship behavior (OCB). It examines which subscales of teacher empowerment can best predict these outcomes. The data were collected through a questionnaire returned by a sample of…
Vandenberghe, Christian; Panaccio, Alexandra
2012-01-01
Using work on self-concepts and Conservation of Resources theory, the present research examined the motivational underpinnings of continuance commitment's subcomponents of perceived sacrifice and few alternatives. Study 1 (N=208) found job scope to be positively related to perceived sacrifice commitment, and negatively related to few alternatives…
De Goede, Irene H. A.; Branje, Susan; van Duin, Jet; VanderValk, Inge E.; Meeus, Wim
2012-01-01
This five-wave longitudinal study examines linkages between adolescents' perceptions of romantic relationship commitment and the development of adolescents' perceptions of commitment to parents and friends. A total of 218 early-to-middle adolescents (39.0 percent boys) and 185 middle-to-late adolescents (30.8 percent boys) participated.…
Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves
Tuan, Hoang-Trong Minh; Williams, George S. B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet
2011-01-01
A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...
Miedaner, Felix; Kuntz, Ludwig; Enke, Christian; Roth, Bernhard; Nitzsche, Anika
2018-03-15
Physician and nursing shortages in acute and critical care settings require research on factors which might drive their commitment, an important predictor of absenteeism and turnover. However, the degree to which the commitment of a physician or a nurse is driven by individual or organizational characteristics in hospitals remains unclear. In addition, there is a need for a greater understanding of how antecedent-commitment relationships differ between both occupational groups. Based on recent findings in the literature and the results of a pilot study, we investigate the degree to which selected individual and organizational characteristics might enhance an employee's affective commitment working in the field of neonatal intensive care. Moreover, our aim is to examine the different antecedent-commitment relationships across the occupational groups of nurses and physicians. Information about individual factors affecting organizational commitment was derived from self-administered staff questionnaires, while additional information about organizational structures was taken from hospital quality reports and a self-administered survey completed by hospital department heads. Overall, 1486 nurses and 540 physicians from 66 Neonatal Intensive Care Units participated in the study. We used multilevel modeling to account for different levels of analysis. Although organizational characteristics can explain differences in an employee's commitment, the differences can be largely explained by his or her individual characteristics and work experiences. Regarding occupational differences, individual support by leaders and colleagues was shown to influence organizational commitment more strongly in the physicians' group. In contrast, the degree of autonomy in the units and perceived quality of care had a larger impact on the nurses' organizational commitment. With the growing number of hospitals facing an acute shortage of highly-skilled labor, effective strategies on the
Policy Uncertainty, Investment and Commitment Periods
Energy Technology Data Exchange (ETDEWEB)
NONE
2007-07-01
Today's investment decisions in key sectors such as energy, forestry or transport have significant impacts on the levels of greenhouse gas (GHG) emissions over the coming decades. Given the economic and environmental long-term implications of capital investment and retirement, a climate mitigation regime should aim to encourage capital investment in climate-friendly technologies. Many factors affect technology choice and the timing of investment, including investor expectations about future prices and policies. Recent international discussions have focused on the importance of providing more certainty about future climate policy stringency. The design of commitment periods can play a role in creating this environment. This paper assesses how the length of commitment periods influences policy uncertainty and investment decisions. In particular, the paper analyses the relationship between commitment period length and near term investment decisions in climate friendly technology.
Dávila, Ma Celeste; Jiménez García, Gemma
2012-03-01
The general purpose of this work is to analyze the overlap between organizational identification and commitment. Specifically, our study focuses on the analysis of the differences and similarities between sense of belonging (a dimension of organizational identification) and affective commitment (a dimension of organizational commitment). In order to do this, we analyzed their discriminant validity and raised their relationship with variables that previous research had showed like precedent and subsequent variables of them: value congruence, perceived support, organizational citizenship behavior, and intention to continue in the organization. A total of 292 people at one organization completed surveys measuring the variables previously described. The results showed that sense of belonging and affective commitment are different concepts and they have different relationships with relation to precedent and subsequent variables. Affective commitment seems to be more useful than sense of belonging to predict organizational citizenship behavior aimed at the organization and intention to continue. Some practical implications are described.
28 CFR 522.11 - Civil contempt commitments.
2010-07-01
... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Civil contempt commitments. 522.11..., CLASSIFICATION, AND TRANSFER ADMISSION TO INSTITUTION Civil Contempt of Court Commitments § 522.11 Civil contempt commitments. Inmates can come into Bureau custody for civil contempt commitments in two ways: (a) The U.S...
Commitment Elements Reframed (Antecedents & Consequences) for Organizational Effectiveness
Fornes, Sandra L.; Rocco, Tonette S.
2004-01-01
The purpose of this paper is to identify theories of commitment in the workplace to develop a framework that helps the field create higher levels of commitment, productivity, and satisfaction. The paper is organized into five main sections: the method, commitment in the workplace, mapping workplace commitment, and the implications for HRD and…
Research on nonlinear stochastic dynamical price model
International Nuclear Information System (INIS)
Li Jiaorui; Xu Wei; Xie Wenxian; Ren Zhengzheng
2008-01-01
In consideration of many uncertain factors existing in economic system, nonlinear stochastic dynamical price model which is subjected to Gaussian white noise excitation is proposed based on deterministic model. One-dimensional averaged Ito stochastic differential equation for the model is derived by using the stochastic averaging method, and applied to investigate the stability of the trivial solution and the first-passage failure of the stochastic price model. The stochastic price model and the methods presented in this paper are verified by numerical studies
Stochastic volatility of volatility in continuous time
DEFF Research Database (Denmark)
Barndorff-Nielsen, Ole; Veraart, Almut
This paper introduces the concept of stochastic volatility of volatility in continuous time and, hence, extends standard stochastic volatility (SV) models to allow for an additional source of randomness associated with greater variability in the data. We discuss how stochastic volatility...... of volatility can be defined both non-parametrically, where we link it to the quadratic variation of the stochastic variance process, and parametrically, where we propose two new SV models which allow for stochastic volatility of volatility. In addition, we show that volatility of volatility can be estimated...
Stochastic Reachability Analysis of Hybrid Systems
Bujorianu, Luminita Manuela
2012-01-01
Stochastic reachability analysis (SRA) is a method of analyzing the behavior of control systems which mix discrete and continuous dynamics. For probabilistic discrete systems it has been shown to be a practical verification method but for stochastic hybrid systems it can be rather more. As a verification technique SRA can assess the safety and performance of, for example, autonomous systems, robot and aircraft path planning and multi-agent coordination but it can also be used for the adaptive control of such systems. Stochastic Reachability Analysis of Hybrid Systems is a self-contained and accessible introduction to this novel topic in the analysis and development of stochastic hybrid systems. Beginning with the relevant aspects of Markov models and introducing stochastic hybrid systems, the book then moves on to coverage of reachability analysis for stochastic hybrid systems. Following this build up, the core of the text first formally defines the concept of reachability in the stochastic framework and then...
Momentum Maps and Stochastic Clebsch Action Principles
Cruzeiro, Ana Bela; Holm, Darryl D.; Ratiu, Tudor S.
2018-01-01
We derive stochastic differential equations whose solutions follow the flow of a stochastic nonlinear Lie algebra operation on a configuration manifold. For this purpose, we develop a stochastic Clebsch action principle, in which the noise couples to the phase space variables through a momentum map. This special coupling simplifies the structure of the resulting stochastic Hamilton equations for the momentum map. In particular, these stochastic Hamilton equations collectivize for Hamiltonians that depend only on the momentum map variable. The Stratonovich equations are derived from the Clebsch variational principle and then converted into Itô form. In comparing the Stratonovich and Itô forms of the stochastic dynamical equations governing the components of the momentum map, we find that the Itô contraction term turns out to be a double Poisson bracket. Finally, we present the stochastic Hamiltonian formulation of the collectivized momentum map dynamics and derive the corresponding Kolmogorov forward and backward equations.
Stochastic Analysis : A Series of Lectures
Dozzi, Marco; Flandoli, Franco; Russo, Francesco
2015-01-01
This book presents in thirteen refereed survey articles an overview of modern activity in stochastic analysis, written by leading international experts. The topics addressed include stochastic fluid dynamics and regularization by noise of deterministic dynamical systems; stochastic partial differential equations driven by Gaussian or Lévy noise, including the relationship between parabolic equations and particle systems, and wave equations in a geometric framework; Malliavin calculus and applications to stochastic numerics; stochastic integration in Banach spaces; porous media-type equations; stochastic deformations of classical mechanics and Feynman integrals and stochastic differential equations with reflection. The articles are based on short courses given at the Centre Interfacultaire Bernoulli of the Ecole Polytechnique Fédérale de Lausanne, Switzerland, from January to June 2012. They offer a valuable resource not only for specialists, but also for other researchers and Ph.D. students in the fields o...
THE ASSOCIATION OF ISLAMIC BASED CARING MODEL AND COMMITMENT TO ORGANIZATION IN STAFF NURSES
Directory of Open Access Journals (Sweden)
Yuda Ayu Timorita
2017-12-01
Full Text Available Background: Strong organizational commitment is needed by hospitals to attract and retain nursing staffs in order to consistently deliver good quality of nursing services. The decrease in organizational commitment among nurses can cause many losses to the organization, including increased organizational spending, breakdown in patient care, and cause performance trends that appear not for the benefit of the organization or unit, but more for personal self-interest. Objective: To analyze the relationship of the application of Islamic Based Caring (IBC model with organizational commitment among nurses. Methods: This was a correlation analytic research with cross sectional design. There were 108 nurses selected using a propotionate stratified random sampling. Islamic Based Caring was measured using a questionnaire developed based on the theory of Suhartini Ismail (2016, and organizational commitment was measured using a questionnaire developed based on the concept of Caldwell, O’Reilly & Chatmann (1990 and Mowday, Porter dan Steers (1982 in Asmaningrum (2009. Logistic regression and forward stepwise (conditional method were used for data analysis. Results: There was a statistically significant correlation of a healing presence (p=0.000, caring relationship (p=0.010, caring environment (p=0.045 and belief in God (p=0.000. Belief in God (Allah SWT has the highest correlation (OR=6.660 with organizational commitment among nurses. Conclusion: There is a positive and significant relationship between the implementation of Islamic Based Caring with the organization's commitment among nurses.